an d f
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Development Document for the Proposed Revisions to the National
Pollutant Discharge Elimination System Regulation and the
Effluent Guidelines for
Concentrated Animal Feeding Operations
Carol M. Browner
Administrator
J. Charles Fox
Assistant Administrator, Office of Water
Sheila E. Frace '
Director, Engineering and Analysis Division
Donald F. Anderson
Chief, Commodities Branch
Janet Goodwin
Project Manager
Paul H. Shriner
Project Engineer
Engineering and Analysis Division
Office of Science and Technology
U.S. Environmental Protection Agency
Washington, D.C. 20460
January 2001
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ACKNOWLEDGMENTS AND DISCLAIMER
This report has been reviewed and approved for publication by the Engineering
and Analysis Division, Office of Science and Technology. This report was
prepared with the support of Tetra Tech, Inc., and Eastern Research Group, Inc.,
under the direction and review of the Office of Science and Technology.
Neither the United States, government nor any of its employees, contractors,
subcontractors, or other employees makes any warranty, expressed or implied, or
assumes any legal liability or responsibility for any third party's use of, or the
results of such use of, any information, apparatus, product, or process discussed in
this report, or represents that its use by such a third parity would not infringe on
privately owned rights.
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Chapter 1 Introduction and Legal Authority
1.0 Introduction and Legal Authority
1.1 Clean Water Act (CWA)
1.1.1 National Pollutant Discharge Elimination System (NPDES) .\ ........ i ~2
1.1.2 Effluent Limitations Guidelines and Standards 1 2
1.2 Pollution Prevention Act (PPA)
1.3 Regulatory Flexibility Act (RFA) as Amended by the Small --•-••-
Business Regulatory Enforcement Fairness Act of 1966 (SBREFA) 1.5
Chapter 2 Summary and Scope of Proposed Regulation 2 j
2.0 Summary and Scope of Proposed Regulation ..... 2\
2.1 National Pollutant Discharge Elimination System (NPDES) ..'........... 2-l
2.1.1 Applicability of the proposed Regulation ....... 2-1
2.1.2 Summary of Proposed Revisions to NPDES Regulations .... 2-3
2.2 Effluent Limitations Guidelines and Standards , 25
2:2.1 Applicability of the Proposed Regulations 2-5
2:2.2 Summary of Proposed Revisions to Effluent Limitations
i Guidelines and Standards
2.2.2.1 Best Practicable Control Technology (BPT) ..; '2-8
2.2.2.2 Best Control Technology (BCT) 2_8
2.2.2.3 Best Available Technology (BAT) 2_9
2.2.2.4 New Source Performance Standards (NSPS) 2-9
Chapters Data Collection Activities
3.0 Data Collection Activities 3~1
3.1 Summary of EPA's Site Visit Program 3 "l
3.2 Industry Trade Associations
3.3 U.S. Department of Agriculture (USDA) \.
3.3.1 National Agricultural Statistics Service (NASS) 3.4
3.3.2 Animal and Plant Health Inspection Service (APHIS)/
National Animal Health Monitoring System (NAHMS) 3.6
3.3r3 Natural Resources Conservation Services (NRCS) ... 3_g
3.3.4 Economic Research Services (ERS) 30
3.4 Literature Sources
3.5 References .. 3-9
3-9
in
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4-1
Chapter 4 Industry Profiles
4.0 Introduction •
4-2
4.1 Swine Industry Description
4.1.1 Distribution of Swine Operations by Size and Regin 4-4
4.1.1.1 National Overview - 4~4
4.1.1.2 Operations by Size Class ^
4.1.1.3 Regional Variation in Hog Operations 4-5
4.1.2 Production Cycles of Swine 4"9
4.1.3 Swine Facility Types and Management 4'12
4.1.4 Swine Waste Management Practices 4-1'
4.1.4.1 Waste Management Practices by Operation
Size and Geographical Location 4-21
4-29
4.1.5 Pollution Reduction
4.1.5.1 Swine Feeding Strategies 4'29
4152 Waste and Waste Water Reductions • 4-32
• ' 4 33
4.16 Waste Disposal . J '
4-39
4.2 Poultry Industry ^
' id'-Xtf)
4.2.1 Broiler Sector •
4 2.1.1 Distribution of Broiler Operations by
4-4.1
Size and Region ^^A
4.2.1.2 Production Cycles of Broilers 4-44
4.2.1.3 Broiler Facility Types and Management 4-44
4.2.1.4 Broiler Waste Management Practices : • • • 4-45
4.2.1.5 Pollution Reduction 4~46
4.2.1.6 Waste Disposal 4~47
4-49
4.2.2 Layer Sector •
4.2.2.1 Distribution of Layer Operations by Size and Region 4-50
4.2.2.2 Production Cycles of Layers and Pullets •• 4-53
4.2.2.3 Layer Facility Types and Management 4-54
4.2.2.4 Layer Waste Management Practices 4-55
4.2.2.5 Layer Egg Wash Water 4'56
4.2.2.6 Waste and Wastewater Reductions 4-57
4.2.2.7 Waste Disposal .- 4'58
4.2.3 Turkey Sector ..' 4"
4231 Distribution of Turkey Operations by Size and
Region -: • 4'61
4.2.3.2 Production Cycles of Turkeys 4'63
4.2.3.3 Turkey Facility Types and Management 4-64
4.2.3.4 Turkey Waste Management Practices 4-65
4.2.3.5 Pollution Reduction 4"65
'< iv
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4.2.3.6 Waste Disposal ..... ^; .... 4-66
4.3 Dairy Industry ? 4-66
4.3.1 Distribution of Dairy Operations by Size and Region 4-67
14.3.2 Dairy Production Cycles '. 4-70
4.3.2.1 MilkHerd 4-70
4.3.2.2 Calves, Heifers, and Bulls ., 4-71
14.3.3 Stand-Alone Heifer Raising Operations 4-72
4.3.4 Dairy Facility Management 4-74
4.3.4.1 Housing Practices '. 4-74
4.3.4.2 Flooring and Bedding .....!... 4-78
; 4.3.4.3 Feeding and Watering Practices 4-79
4.3.4.4 Milking Operations 4-80
4.3.4.5 Rotational Grazing 4-82
4.3.5 Dairy Waste Management Practices 4-85
4.3.5.1 Waste Collection 4-86
4.3.5.2 Transport 4-87
4.3.5.3 Storage, Treatment, and Disposal ... 4-87
4.4 Beef Industry 4-88
4.4.1 Distribution of Beef Industry by Size and Region 4-89
4.4.2 Beef Production Cycles 4-93
4.4.3 Beef Feedlot Facility Management 4-93
4.4.3.1 Feedlot Systems 4-93
4.4.3.2 Feeding and Watering Practices 4-95
4.4.3.3 Water Use and Wastewater Generation 4-95
4.4.3.4 Climate ;. 4-96
4.4.4 Backgrounding Operations 4-96
4.4.5 Veal Operation 4.97
4.4.6 Cow-Calf Operations 4-98
4.4.7 Waste Management Practices 4-98
4.4.7.1 Waste Collection 4-99
4.4.7.2 Transport 4-100
4.4.7.3 Storage, Treatment, and Disposal 4-100
4.5 References : 4-10.1
Chapter 5 Industry Subcategorization for Effluent Limitations Guidelines and Standards 5-1
5.0 Introduction 5-1
5.1 Factors Considered as the Basis for Subcategorization 5-2
5.1.1 Basis for Subcategorization in the Existing ELG 5-2
5.1.2 Production Processes '. 5-3
5.1.3 Animal Type 5-3
v
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5.1.4 Water Use Practices 5-5
5.1.5 Wastes and Wastewater Characteristics 5-6
5.1.6 Facility Age 5-7
5.1.7 Facility Size 5-7
5.1.8 • Geographical Location 5-8
5.1.9 Pollution Control Technologies 5-8
5.1.10 Non-Water Quality Environmental Impacts 5-9
5.2 Proposed Revised Subcategories 5-9
5.3 References ; 5-10
Chapter 6 Wastewater Characterization and Manure Characteristics 6-1
6.0 Introduction 6-1
6.1 Swine Waste : 6-1
6.1.1 Quantity of Manure Generated 6-3
6.1.2 Description of Waste Constituents and Concentrations 6-4
6.2 Poultry Waste 6-11
i
6.2.1 Broiler Waste Characteristics 6-11
6.2.1.1 • Quantity of Manure Generated 6-11
6.2.1.2 Description of Waste Constituents and Concentrations ... 6-12
6.2.2 Layer Waste Characteristics 6-15
6.2.2.1 Quantity of Manure Generated 6-15
6.2.2.2 Description of Waste Constituents and Concentrations .... 6-15
6.2.3 Turkey Waste Characteristics 6-18
6.2.3.1 Quantity of Manure Generated 6-18
6.2.3.2 Description of Waste Constituents and Concentrations ... 6-19
6.3 Dairy Waste , 6-23
6.3.1 Quantity of Manure Generated 6-23
6.3.2 Description of waste Constituents and Concentrations 6-24
6.3.2.1 Composition of "As-Excreted" Manure 6-24
6.3.2.2 Composition of Stored or Managed Waste 6-26
6.3.2.3 Composition of Aged Manure/Waste 6-28
6.4 Beef and Heifer Waste 6-29
6.4.1 Quantity of Manure Generated 6-29
6.4.2 Description of Waste Constituents and Concentrations 6-30
6.4.2.1 Composition of "As-Excreted" Manure 6-30
6.4.2.2 Composition of Beef Feedlot Waste 6-33
6.4.2.3 Composition of Aged Manure 6-35
6.4.2.4 Composition of Runoff from Beef Feedlots 6-35
6.5 Veal Waste 6-36
VI
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6.5.1 Quantity of Manure Generated ... 6-36
6.5.2 Description of Waste Constituents and Concentrations 6-37
6.6 References 5.39
Chapter 7 Pollutants of Interest 7_j
7.0 Introduction 7_j
7.1 Conventional Waste Pollutants ., 7_2
7.2 Nonconventional Pollutants 7_2
7.3 Priority Pollutants 7.6
7.4 References j_j
Chapter 8 Treatment Technologies and Best Management Practices 8-1
8.0 Introduction g.j
8.1 Pollution Prevention Practices g_l
8J.1 Feeding Strategies g-1
8.1.1.1 Swine Feeding Strategies ...8-2
8.1.1.2 Poultry Feeding Strategies 8-6
8.1.1.3 Dairy Feeding Strategies 8-9
8.1.2 Reduced Water Use and Water Content of Waste 8-16
8.2 Manure/Waste Handling, Storage, and Treatment Technologies 8-46
8.2.1 Waste Handling Technologies and Practices 8-46
8.2.2 Waste Storage Technologies and Practices 8-53
8.2.3 Waste Treatment Technologies and Practices 8-68
8.2.3.1 Treatment of Animal Waste and Wastewater 8-68
8.2.3.2 Mortality Management 8-124
8.3 Nutrient Management Planning 8-134
8.3.1 Comprehensive Nutrient Management Plant (CNMPs) 8-135
8.3.2 Nutrient Budget Analysis 8-139
8.3.2.1 Crop Yield Goals ', 8-140
8.3.2.2 Crop Nutrient Needs 8-142
8.3.2.3 Nutrients Available in Manure 8-144
8.3.2.4 Nutrients Available in Soil 8-156
: 8.3.2.5 Manure Application Rates and Land Requirements 8-160
8.3.3 Record Keeping 8-163
8.3.4 Certification of Nutrient Management Planners : 8-164
8.4 Land Application and Field Management 8-166
8.4-1 Application Timing 8-166
8.4.2 Application Methods ; 8-167
8.4.3 Manure Application Equipment 8-169
8.4.4 Runoff Control ; 8-182
vii
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8.5 References '. ,.'.. -. 8-201
Chapter 9 NPDES Regulatory Options . :... - 9-1
9.0 Introduction to NPDES Program : 9-1
9.1 • Industry Compliance with Existing Regulations 9-2
9.1.1 Approach and Assumptions for Identifying AFOs That Are
Currently Subject to Regulation 9-3
9.1.2 Livestock Categories 9-7
9.1.2.1 Beef. 1 9-7
9.1.1,2 Dairy 9-8
9.1.2.3 Swine 9-9
9.1.2.4 Layers 9-10
9.1.2.5 Broilers .. • 9-11
9.1.2.6 Turkeys 9-11
9.1.3 Summary of Feeding Operations in Compliance by Size and Type 9-12
9.2 Affected Entities Under Proposed Scenarios for Revised NPDES CAFO Rule ... 9-13
• 9.2.1 Regulatory Scenarios • • 9-14
9.2.2 Scenario 1: Three-Tier Structure • 9-14
9.2.3 Scenario 2: Three-Tier Structure with Revised Criteria for Defining a
Middle-Tier CAFOf 9-17
9.2.4 Scenario 3: Three-Tier Structure with Check Box Certification Form for
Middle Tier .......'. 9-23
9.2.5 Scenario 4: Two-Tier Structure 9-27
9.2.5.1 Scenario 4a: Two Tier Structure at 500 AU 9-27
9.2.5.2 Scenario 4b: Two-Tier Structure at 500 AU 9-29
9.2.6 Summary of CAFOs Requiring Permits/Applications Under Regulatory
Scenarios , 9-32
9.3 State and Federal Administrative Costs for General and Individual Permits 9-32
9.3.1 Unfunded Mandates Reform Act 9-32
9.3.2 State and Federal Administrative Unit Costs for General Permits 9-33
9.3.3 State and Federal Administrative Unit Costs for Individual Permits 9-35
9.4 State and Federal Administration Costs by Regulatory Scenario 9-36
9.4.1 Scenario 1: State and Federal Administrative Costs for General and
Individual Permits ', 9-36,
9.4.2 Scenario 2: State and Federal Administrative Costs for General and
Individual Permits • • • • 9-38
9.4.3 Scenarios: State and Federal Administrative Costs for General and'
Individual Permits • • • 9-39
9.4.4 Scenario 4: State and Federal Administrative Costs for General and
Individual Permits 9-41
9.4.5 Summary of State and Federal Administration Costs by
Vlll
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Regulatory Scenario 9.43
9.5 Changes to NPDES Regulations _ 9.44
9.5.1 Definition of AFO as It Relates to Pastures and Rangeland 9-44
9.5.2 Definition of AFO as It Relates to Land Application Areas 9-45
9.5.3 Elimination of the Term "Animal Units" .. 9.47
9.5.4 Elimination of Multipliers for Mixed Animal Types 9-47
9.5.5 Elimination of 25/24 Storm Permit Exemption 9.49
9.5.6 No Potential to Discharge/ Duty to Apply 9.50
9.5.7 Applicability to All Poultry 9.51
9.5.8 Applicability to Immature Animals 9.54
9.5.9 NPDES Thresholds for Animal Types not Covered by the ELG 9-56
9.5.10 Duty to Maintain Permit Coverage Until Closure 9-56
9.5.11 Assessment of Direct Hydrological Connection to Surface Water as Permit
Condition .. -'. 9_5g
9.6 Land Application of Manure 9.59
9.6.2 Other Special Permit Conditions 9_60
9.6.3 Non-CAFO Land Application Activities 9-61
9.7 NPDES Reporting and Recordkeeping Requirements 9-62
9.7.1 PNPNotification 1.9-63
9.7.2 Certification from Non-CAFO Recipients of CAFO-Generated Manure . 9-64
9.8 References 9_68
Chapter 10 Technology Options Considered 10-1
10.1 Changes to Effluent Guidelines Applicability 10-1
10.2 Changes to Effluent Limitations and Standards '. 1Q-2
10.2.1 Current Requirements jQ_2
10.2.2 Best Practicable Control Technology Limitation Currently
Available (BPT) 10_2
10.2.3 Proposed Basis for BPT Limitations 10-12
10.2.4 Best Control Technology for Conventional Pollutants (BCT) 10-13
10.2.5 Best Available Technology Economically Achievable (BAT) 10-14
10.2.6 Propose Basis for BAT . 10-21
10.2.6.1 BAT Requirements for the Beef and Dairy Subcategories . 10-21
10.2.6.2 BAT Requirements for the Swine, Veal, and Poultry
Subcategories 10-25
10.2.7 New'Source Performance Standards io-32
10.2.8 Pretreatment Standards for New or Existing
Sources (PSES and PSNS) 10-36
Chapter 11 Model Farms and Costs of Technology Bases for Regulation 11-1
IX
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11.0 Introduction 11-1
11.1 Overview of Cost Methodology 11-2
11.2 Development of Model Farm Operations 11-3
11.2.1 Swine Operations 11-5
11.2.1.1 Housing , 11-5
11.2.1.2 Waste Management Systems 11-6
11.2.1.3 SizeGroup 11-7
11.2.1.4 Region 11-8
11.2.2 Poultry Operations 11-8
11.2.2.1 Housing 11-9
11.2.2.2 Waste Management Systems 11-9
11.2.2.3 Size Group 11-9
11.2.2.4 Region 11-10
11.2.3 Turkey Operations - • 11-12
11.2.3.1 Housing 11-12
11.2.3.2 Waste Management Systems 11-12
11.2.3.3 Size Groups ..... 11-13
11.2.3.4 Region 11-13
11.2.4 Dairy Operations 11-13
11.2.4.1 Housing 11-14
11.2.4.2 Waste Management Systems 11-14-
11.2.4.3 Size Group * 11-17
11.2.4.4 Region 11-17
11.2.5 Beef Feedlots 11-17
11.2.5.1 Housing 11-18
11.2.5.2 Waste Management Systems 11-18
11.2.5.3 Size Group 11-18
11.2.5.4 Region 11-20
11.2.6 Veal Operations 11-20
11.2.6.1 Housing 11-20
11.2.6.2 Waste Management Systems 11-21
11.2.6.3 SizeGroup .11-21
11.2.6.4 Region 11-22
11.2.7 Heifer Grower Operations 11-22
11.2.7.1 Housing - H-22
11.2.7.2 Waste Management Systems 11-22
11.2.7.3 Size Group 11-22
11.2.7.4 Region H-23
11.3 Design and Cost of Waste and Nutrient Management Technologies 11-23
11.3.1 Manure and Nutrient Production 11-24
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11.3.2 Available Acreage 11-28
11.3.2.1 Agronomic Application Rates 11-28
11.3.2.2 Category 1 and2 Acreage 11-31
11.3.3 Nutrient Management Planning ........ 11-31
11.3.4 Facility Upgrades 11-32
11.3.5 Land Application .....' , .11-35
11.3.6 Off-Site Transport of Manure 11-35
11.4 Development of Frequency Factors 11-36
11.5 Summary of Estimated Model Farm Costs by Regulatory Option 11-38
11.6 'References : 11-38
Chapter 12 Pollutant Reduction Estimates 12-1
12.1 Feeding Operation Runoff Pollutant Loads 12-1
12.2 Land Application Field Runoff Loads 12-5
12.2.1 Industry Characterization 12-6
12.2.2 Estimation of Sample FarmLoads 12-8
12.2.3 Evaluation of Modeling Results 12-9
12.2.4 Results of the National Loading Analysis 12-10
12.3 Subsurface Leaching 12-12
12.4 Volatilization and Deposition 12-14
12.5 References 12-16
Chapter 13 Non-Water Quality Impacts 13-1
. 13.0 'introduction 13-1
13.1 Overview of Analysis and Pollutants 13-2
13.2 Air Emissions from Animal Feeding Operations 13-5
13.2.1 Greenhouse Gas Emissions from Manure Management
Systems 13-6
13.2.2 Ammonia and Hydrogen Sulfide Emissions From Animal
Confinement and Manure Management Systems 13^7
13.2.3 Criteria Air Emissions From Energy Recovery Systems 13-8
13.3 Air Emissions From Land Application Activities 13-8
13.4 Air Emissions From Vehicles . - - - 13-9
13.5 Energy Impacts 13-10
13.6 Industry-Level NWQI Estimates ., , 13-10
13.6.1 Summary of Air Emissions for Beef and
Dairy Subcategories 13-10
13.6.2 Summary of Air Emissions for Swine, Poultry, and Veal
Subcategories 13-12
13.6.3 Energy Impacts 13-15
xi
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LIST OF TABLES
Table 2-1. Number of Animals by Sector for 300 and 1,000 AU Equivalents '. 2-2
Table 2-2 Basis Considered for Subcategorization of CAFOs ; 2-5
Table 2-3 Summary of Technology Basisxii for CAFO Industry .2-10
•Table 3-1. Number of Site Visits Conducted by EPA for the Various Animal •:
Industry Sectors 3_2
Table 4-1. Animal Feeding Operation (AFO) Production Regions .4-2
Table 4-2. Distribution of Swine Operations by Size and Region 4.4
Table 4-3. Percentage of U.S. Hog Operations and Inventory by Herd Size 4-5
Table 4-4. Total Number of Swine Operations by Region, Operation Type, and Size in 1997 4-6
Table 4-5. Average Number of Swine at Various Operations by Region Operation Type, and
Size in 1997 ... 4.7
Table 4-6. Distribution of Swine Herd by Region, Operation Type, and Size in 1997 4-8
Table 4-7. Distribution of Animal Type in Swine Herds at Combined Facilities by Region,
Operation Type, and Size in 1997 4.9
Table 4-8. Production Measures of Pigs 4_10
Table 4-9. Age of Pigs Leaving Grow-Finish Unit in 1995 4-11
Table 4-10. Frequency of Production Phases in 1995 on Operations that Marketed Less
Than 5,000 Hogs in a 6-month Period 4_11
Table 4-11. Frequency of Production Phases in 1995 on Operations that Marketed
5,000 or More Hogs in a 6-Month Period 4_12
Table 4-12. Summary of Major Swine Housing Facilities 4-13
Table 4-13. Housing Frequency (in percent) in 1995 of Farrowing Facilities at Operations
That Marketed Fewer Tha n 5,000 Hogs in a 6-Month Period 4-15
Table 4-14. Housing Frequency (in percent) in 1995 of Farrowing Facilites at Operations
That Marketed 5,000 or More Hogs in a 6-Month Period 4-15
Table 4-15. Housing Frequency (in percent) in 1995 of Nursery Facilities at Operations
That Marketed Fewer Than 5,000 Hogs in a 6-Month Period 4-16
Table 4-16. Housing Frequency (in percent) in 1995 of Nursery Facilities at Operations
That Marketed 5,000 or More Hogs in a 6-Month Period .4-16
Table 4-17. Housing Frequency (in percent) in 1995 of Finishing Facilities at Operations
That Marketed Fewer Than 5,000!Hogs in a 6-Month Period 4-16
Table 4-18. Housing Frequency (in percent) in 1995 of Finishing Facilities at Operations
That.Marketed 5,000 or More Hogs in a 6-Month Period 4-17
Table 4-19. Percentage of Swine Facilities With Manure Storage in 1998 4-18
Table 4-20. Frequency (in percent) of Operations in 1995 by Type of Waste
Management System Used Most in the Farrowing Phase 4-22
Table 4-21. Frequency (in percent) of Operations in 1995 by Type of Waste
Management System Used Most in the Nursery Phase 4-23
Table 4-22. Frequency (hi percent) of Operations in 1995 by Type of Waste
Management System Used Most in the Finishing Phase 4-23
Table 4-23. Frequency (in percent) of Operations in 1995 That Used Any of the
Following Waste Storage Systems by Size of Operation 4-24
xii
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Table 4-24. Frequency (in percent) of Operations in 1995 That Used Any of the
Following Waste Storage Systems by Region for Operations that
Marketed 5,000 or More Hogs in a 12-Month Period 4-25
Table 4-25. Distribution of Predominant Waste Management Systems in the Pacific
Region in 1997 4-26
Table 4-26. Distribution of Predominant Waste Management Systems in the Central
Regionin 1997 4-27
Table 4-27. Distribution of Predominant Waste Management Systems in the
. Mid-Atlantic Region in 1997 4-27
Table 4-28. Distribution of Predominant Waste Management Systems in the
South Region in 1997 4-28
Table 4-29. Distribution of Predominant Waste Management Systems in the
Midwest Region in 1997 .. 4-28
Table 4-30. Theoretical Effects of Reducing Dietary Protein and Supplementing With Amino
Acids on Nitrogen Excretion by 200-lb Finishing Pig 4-30
Table 4-31. Theoretical Effects of Dietary Phosphorus Level and Phytase
Supplementation (200-lb Pig) ., 4-31
Table 4-32. Effect of Microbial Phytase on Relative Performance of Pigs 4-32
Table 4-33. Effect of Microbial Phytase on Increase in Phosphorus Digestibility by Age of
Pigs and the Recommended Rates for Inclusion of Phytase in Each Phase 4-32
Table 4-34. Percentage of Operations in 1995 That Used or Disposed of Manure and
Wastes as Unseparated Liquids and Solids 4-33
Table 4-35. Percentage of Operations hi 1995 That Marketed Fewer Than 5,000 Hogs in a
12-Month Period and That Used the Following Methods of Use/Disposal by Region. 4-34
Table 4-36. Percentage of Operations in 1995 That Marketed 5,000 or More Hogs in a 12-Month
Period and That Used the Following Methods of Use/Disposal by Region 4-34
Table 4-37. Method of Manure Application in 1995 on Land by Operations That
Marketed Fewer Than 5,000 Hogs in a 12-Month Period 4-35
Table 4-38. " Method of Manure Application in 1995 on Land by Operations That
Marketed 5,000 or More Hogs in a 12-Month Period 4-35
Table 4-39. Percentage of Swine Grow-Finish Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure 4-36
Table 4-40. Percentage of Swine Farrowing Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure 4-36
Table 4-41. Percentage of Swine Farrow-Finish Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure .' 4-36
Table 4-42. Method of Mortality Disposal on Operations That Marketed Fewer Than
2,500 Hogs in a 6-Month Period in 1995 4-38
Table 4-43. Method of Mortality Disposal on Operations That Marketed 2,500 or
More Hogs in a 6-Month Period in 1995 , 4-39
Table 4-44. Broiler Operations and Production in the United States 1982-1997 4-41
Table 4-45. Total Number of Broiler Operations by Region and Operation Size in 1997 4-42
Table 4-46. Average Number of Chickens at Broiler Operations By Region and
Operation Size in 1997 4^3
Table 4-47. Distribution of Chickens by Region and Operation Size in 1997 4-43
Table 4-48. Percentage of Broiler Dominated Poultry Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure 4-48
Xlll
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Table 4-49. Operations With Inventory of Layers or Pullets 1982-1997 4-50
Table 4-50. Number of Operations in 1997 and Average Number of Birds at Operations
with Layers or Pullets or Both Layers and Pullets in 1997 4-51
Table 4-51. Number of Operations in 1997 With Laying Hens by Region
and Operation Size in 1997 , ... 4-52
Table 4-52. Average Number of Chickens at Operations in 1997 With Laying Hens by
Region and Facility Size ; 4-52
Table 4-53. Distribution of Chickens at Operations in 1997 With Laying
Hens by Region and Facility Size 4-53
Table 4-54. Summary of Manure Storage, Management, and Disposal 4-55
Table 4-55. Frequency of Primary Manure Handling Method by Region 4-56
Table 4-56. Percentage of Operations by Egg Processing Location and Region 4-57
Table 4-57. Percentage of Operations by Egg Processing Location and Operation Size 4-57
Table 4-58. Percentage of Layer Dominated Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure 4-58
Table 4-59. Percentage of Pullet Dominated Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure 4-59
Table 4-60. Frequency of Disposal Methods for Dead Layers for All Facilities 4-59
Table 4-61. Frequency of Disposal Methods for Dead Layers for Facilities with <100,000 Birds . 4-60
Table 4-62. Frequency of Disposal Methods for Dead Layers for Facilities with >100,000 Birds . 4-60
Table 4-63. Turkey Operations (Ops) in 1997,1992,1987, and 1982 With Inventories of
Turkeys for Slaughter and Hens for Breeding 4-61
Table 4-64. Number of Turkey Operations in 1997 by Region and Operation Size 4-62
Table 4-65. Average Number of Birds at Turkey Operations in 1997 by Region and Operation
Size i 4-63
Table 4-66. Distribution of Turkeys in 1997 by Region and Operation Size ., 4-63
Table 4-67. Percentage of Turkey Dominated Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure 4-66
Table 4-68. Distribution of Dairy Operations by Region and Operation Size in 1997 4-68
Table 4-69. Total Milk Cows by Size of Operation in 1997 4-69
Table 4-70. Number of Dairies by Size and State in 1997 4-69
Table 4-71. Milk Production by State in 1997: , 4-70
Table 4-72. Characteristics of Heifer Raising Operations 4-72
Table 4-73. Distribution of Confined Heifer Raising Operations by Size and Region in 1997 4-73
Table 4-74. Percentage of U.S. Dairies by Housing Type and Animal Group in 1995 4-78
Table 4-75. Types of Flooring for Lactating Cpws 4-78
Table 4-76. Types of Bedding for Lactating Cows 4-79
Table 4-77. Percentage of Dairy Operations With Sufficient, Insufficient, and No Land for
Agronomic Application of Generated Manure 4-88
Table 4-78. Distribution of Beef Feedlots by Size and Region in 1997 4-91
Table4-79. CattleSoldin 1997 4-91
Table 4-80. Number of Beef Feedlots by Size of Feedlot and State in 1997a 4-92
Table 4-81. Distribution of Veal Operations by Size and Region in 1997 4-93
Table 4-82. Percentage of Beef Feedlots With Sufficient, Insufficient, and No
Land for Agronomic Applicatipn of Manure „. 4-101
Table 5-1. Revised ELG Applicability ,!... 5-9
xiv
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Table 6-1. Quantity of Manure Excreted by Different Types of Swine 6-3
Table 6-2. Quantity of Nitrogen Present in Swine Manure as Excreted 6-5
Table 6-3. Quantity of Phosphorus Present in Swine Manure as Excreted 6-5
Table 6^4. Quantity of Potassium Present in Swine Manure as Excreted 6-6
Table 6-5. Comparison of Nutrient Quantity in Manure for Different Storage and
Treatment Methods 6-7
Table 6-6. Percent of Original Nutrient Content of Manure Retained by Various
Management Systems 6-7
Table 6-7. Nutrient Concentrations for Manure in Pit Storage and Anaerobic
Lagoons for Different Types of Swine 6-7
Table 6-8. Comparison of the Mean Quantity of Metals and Other Elements in
Manure for Different Storage and Treatment Methods 6-8
Table 6-9. Comparison of the Mean Concentration of Pathogens in Manure
for Different Storage and Treatment Methods ..6-9
Table 6-10. Type of Pharmaceutical Agents Administered in Feed, Percent of
Operations that Administer Them, and Average Total Days Used 6-9
Table 6-11. Physical Characteristics of Swine Manure by Operation Type and Lagoon System .. 6-10
Table 6-12. Physical Characteristics of Different Types of Swine Wastes 6-10
Table 6-13. Quantity of Manure Excreted for Broilers 6-11
Table 6-14. Consistency of Broiler Manure as Excreted and for Different Storage Methods ..... 6-12
Table 6-15. Nutrient Quantity hi Broiler Manure as Excreted 6-13
Table 6-16. Broiler Liquid Manure Produced and Nutrient Concentrations
for Different Storage Methods 6-13
Table 6-17. Nutrient Quantity in Broiler Litter for Different Storage Methods 6-13
Table 6-18. Quantity of Metals and Other Elements Present in Broiler Manure as
Excreted and for Different Storage Methods 6-14
Table 6-19. Concentration of Bacteria hi Broiler House Litter 6-14
Table 6-20. Quantity of Manure Excreted for Layers 6-15
Table 6-21. Physical Characteristics of Layer Manure as Excreted and for Different
•'• Storage Methods 6-16
Table 6-22. Quantity of Nutrients in Layer Manure as Excreted 6-16
Table 6-23. Annual Volumes of Liquid Layer Manure Produced and Nutrient Concentrations ... 6-17
Table 6-24. Nutrient Quantity in Layer Litter for Different Storage Methods 6-17
Table 6-25. Quantity of Metals and Other Elements Present in Layer Manure as Excreted
. andifor Different Storage Methods 6-17
Table 6-26. Concentration of Bacteria hi Layer Litter 6-18
Table 6-27. Annual Fresh Excreted Manure Production (lb/yr/1,000 Ib of animal mass) 6-19
Table 6-28. Quantity of Nutrients Present hi Fresh Excreted Turkey Manure
(lb/yr/1,000 Ib of animal mass) 6-19
Table 6-29. Water Absorption of Bedding 6-20
Table 6-30. Turkey Litter Composition hi pounds per ton of litter 6-20
Table 6-31. Metal Concentrations hi Turkey Litter (pounds per ton of Utter) 6-21
Table 6^32. Waste Characterization of Turkey Manure Types (lb/ye/1,000 Ib of animal mass) ... 6-21
Table 6-33. Metals and Other Elements Present in Manure (lb/yr/1,000 Ib of animal mass) 6-22
Table 6-34. Turkey Manure'and Litter Bacterial Concentrations (bacterial colonies per
pound of manure) 6-22
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Table 6-35. Turkey Manure Nutrient Composition After LossesBLand Applied Quantities . 6-22
Table 6-36. Weight of Dairy Manure, "As-Excreted" '. 6-24
Table 6-37. Fresh (As-Excreted) Dairy Manure Characteristics Per 1,000 Pounds .
Live Weight Per Day "., 6-25
Table 6-38. Average Nutrient Values in Fresh (As-Excreted) Dairy Manure 6-26
Table 6-39. Dairy Waste CharacterizationCMilking Center 6-27
Table 6-40. Dairy Waste CharacterizationCLagoons 6-28
Table 6-41. Dairy Manure Characteristics Per 1,000 Pounds Live Weight Per
Day From Scraped Paved Surface 6-29
Table 6-42. Weight of Beef and Heifer Manure, "As-Excreted" 6-30
Table 6-43. Fresh Beef and Veal Manure Characteristics Per 1,000 Pound
Live Weight Per Day I 6-32
Table 6-44. Average Nutrient Values in Fresh (As-Excreted) Beef Manure 6-33
Table 6-45. Fresh Heifer Manure characteristics Per 1,000 Pounds Live Weight Per Day 6-33
Table 6-46. Beef Waste Characterization—Feedlot Waste 6-34
Table 6-47. Beef Manure Characteristics Per 1,000 Pounds Live Weight Per Day From •
Scraped Unpaved Surface 6-34
Table 6-48. Percentage of Nutrients in Fresh and Aged Beef Cattle Manure 6-35
Table 6-49. Beef Waste Characterization—Feedlot Runoff Lagoon 6-36
Table 6-50. Average Weight of Veal Manure, "As Excreted" 6-37
Table 6-51. Fresh Veal Manure Characteristics Per 1,000 Pound Live Weigh Per Day 6-38
Table 8-1. Per Cow Reductions in Manure P ;Resulting from Reduced P Intake
During Lactation 8-10
Table 8-2. Performance of Gravity Separation Techniques 8-20
Table 8-3. Summary of Expected Performance of Mechanical Separation Equipment 8-23
Table 8-4. Examples of Bedding Nutrients Concentrations 8-31
Table 8-5. Amount of Time That Grazing Systems May Be Used at Dairy Farms and
Beef Feedlots, by Geographic Region 8-37
Table 8-6. Expected Reduction in Collected Solid Manure and Wastewater at Dairies Using
Intensive Rotational Grazing, per Head r 8-38
Table 8-7. Expected Reduction in Collected Solid Manure and Wastewater at Dairies Using
Intensive Rotational Grazing, per Model Farm 8-39
Table 8-8. Expected Reduction in Collected Solid Manure at Beef Feedlots Using Intensive
Rotational Grazing, per Head 8-40
Table 8-9. Expected Reduction hi Collected Solid Manure at Beef Feedlots Using Intensive
Rotational Grazing, per Model Farm 8-40
Table 8-10. Anaerobic Unit Process Performance : 8-55
Table 8-11. Anaerobic Unit Process Performance 8-71
Table 8-12. Biogas Use Options . 8-72
Table 8-13. Anaerobic Unit Process Performance 8-75
Table 8-14. Operational Characteristics of Aerobic Digestion and Activated Sludge Processes .. 8-78
Table 8-15. Lagoon Sludge Accumulation 8-88
Table 8-16. Lagoon Sludge Accumulation Rates Estimated for Pig Manure 8-89
Table 8-17. Advantages and Disadvantages of Composting 8-107
Table 8-18. Desired Characteristics of Raw Material Mixes 8-108
Table 8-19. Swine Manure Nutrient Content Ranges : , 8-149
xvi
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Table 8-20. Poultry Manure Nutrient Content Ranges 8.150
Table 8-21. Dairy Manure Nutrient Content Ranges ..; '.'.'.'."' 8-151
Table 8-22. Beef Manure Nutrient Content Ranges 8-153
Table 8-23. Maximum P-Fixation Capacity of Several Soils of Varied Clay Contents 8-156
Table 8-24. Recommended Field Size for Soil Sampling '. " " 8_i60
Table 8-25. Correction Factors to Account for Nitrogen Volatilization Losses During Land
Application of Animal Manure 8_168
Table 8-26. Advantages and Disadvantages of Manure Application Equipment 8-169
Table 8-27. Primary Functions of Soil Conservation Practices .'.""".".' 8-188
Table 9-1. Total 1997 Facilities With Confined Animal Inventories by Livestock
Sector and Size „,
Table 9-2. Total Adjusted AFOs by Size and Livestock Sector 9-6
?u!e ol!" K^Sula**1 Beef Feeding Operations by Size Category Assuming Full Compliance " " 9-8
;able9-4. Regulated Dairy Operations by Size Category Assuming Full Compliance 9-9
Table 9-5. Regulated Swine Operations by Size Category Assuming Full Compliance '' 9-10
1 able 9-6. Regulated Layer Operations by Size Category Assuming Full Compliance 9-11
Table 9-7. Regulated Broiler Operations by Size Category Assuming Full Compliance 9-12
Table 9-8. Regulated Turkey Operations by Size Category Assuming Full Compliance 9-12
lab e 9-9. Summary of Effectively Regulated Operations by Size and Livestock Sector 9-13
T w oil Scenario 1 ~ Summa*y of AFOs by Livestock Sector Required to Apply for Permit 9-15
Table 9-11. Scenario 2 - Beef CAFOs Required to Apply for a Permit .. 9 18
Table 9-12. Scenario 2 - Dairy CAFOs Required to Apply for a Permit 919
Table 9-13. Scenario 2 - Heifer CAFOs Required to Apply for a Permit " 9 19
Table 9-14. Scenario 2 - Veal CAFOs Required to Apply for a Permit ....."."!.".'."."" 9-20
Table 9-15. Scenario 2 - Swine CAFOs Required to Apply for a Permit ' 9 20
Table 9-16. Scenario 2 - Layer CAFOs Required to Apply for a Permit 9.21
Table 9-17. Scenario 2 - Broiler CAFOs Required to Apply for a Permit .. 9-21
Table 9-18. Scenario 2 - Turkey CAFOs Required to Apply for a Permit 9 22
Table 9-19. Scenario 2- Summary of CAFOs by Livestock Sector Required
to Apply for a Permit"1 9 22
Table 9-20. Scenario 4a - Summary of CAFOs by Livestock Sector "Required to Apply
foraPermit* ; _ ** * 9_2?
Table 9-21. Scenario 4b - Summary of CAFOs by Livestock Sector Required to Apply
foraPermit 9 3Q
Table 9-22. Scenarios 1-4 - AFOs by Livestock Sector Required to Apply for a Perrnit
or Certify as to Permitting Requirements Under The Proposed Regulations 9-32
Table 9-23. Administrative Costs Associated With a General Permit " " 9.34
Table 9-24. Administrative Costs Associated with an Individual Permit '.'.'.'. 9.35
Table 9-25. State Administrative Costs under Scenario 1 " 9.37
Table 9-26. Federal Administrative Costs under Scenario 1 ........... ' 9*37
Table 9-27, State Administrative Costs under Scenario 2 '.'.'.'.'.'.'.'.'.'.'. 9^38
Table 9-28. Federal Administrative Costs under Scenario 2 '.'.'.'.'.'.'.'.'.'. 9.39
Table 9-29. State Administrative Costs under Scenario 3 9^49
Table 9-30. Federal Administrative Costs under Scenario 3 '.'.'.'.'.'.'.','.'.'.'.'.'. 9.40
Table 9-31. State Administrative Costs under Scenario 4a •'.'.'.'.'.'.'.'.'. 9.41
Table 9-32. Federal Administrative Costs under Scenario 4a ....."....... 9.42
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Table 9-33. State Administrative Costs under Scenario 4b
Table 9-34. Federal Administrative Costs under Scenario 4b • • 9-43
Table 9-35. Total Annualized State and Federal Administrative Costs by Regulatory Option 9-43
Table 9-36: Recipients and Costs for Offsite Locations Receiving Manure from CAFOs 9-65
Table 10-1. Requirements Considered in the Technology Options : 10-14
Table 11-1. Summary of Regulatory Options for CAFOs H"4
Table 11-2. Size Classes for Model Swine Farms H'8
Table 11-3. Size Classes for Model Broiler Farms 11-11
Table 11-4. Size Classes for Model Dry Layer Farms • • • • • H-H
Table 11-5. Size Classes for Model Turkey Farms I.1"13
Table 11-6. Size Classes for Model Dairy Farms n~17
Table 11-7. Size Classes for Model Beef Farms n~20
Table 11-8. Size Classes for Model Veal Farm : 11-21
Table 11-9. Size Classes for Model Heifer Farm • H'23
Table 11-10. Manure and Nutrient Production by Model Farm 11-26
Table 11-11. Crop Information • • H'30
Table 11-12. Regulatory Compliance Costs for Swine Operations 11-41
Table 11-13. Regulatory Compliance Costs for Poultry Operations • 11-76
Table 11-14. Regulatory Compliance Costs for Turkey Operations ' 11-113
Table 11-15. Regulatory Compliance Costs for Dairy Operations 11-127
Table 11-16. Regulatory Compliance Costs for Beef Operations , 11-140
Table 11-17. Regulatory Compliance Costs for Veal Operations 11-157
Table 11-18. Regulatory Compliance .Costs for Heifer Operations 11-166
Table 12-1. Nutrient Loads from Feedlot Runoff by Animal Sector and AFO Regions 12-1
Table 12-2. Constituents of Manure Presented in ASAE (1998) 12-2
Table 12-3. Annual Beef Feedlot Runoff Loading I2'3
Table 12-4. Annual Dairy Feedlot Runoff Loading • • • • I2"4
Table 12-5. Annual Poultry Feedlot Runoff Loading I2"4
Table 12-6 Nutrient Loads (and Percentage Reduction Over Baseline)
for Pre-and Post-Regulation Conditions • • • 12-10
Table 12-7 Pathogen and Metal Loads from Animal Feeding Operations 12-11
Table 12-8 Direct and Indirect Subsurface Nitrogen and Phosphorus Loads 12-14
Table 12-9 Percentages of Land and Water Areas and Runoff for Five Regions
under Consideration 12-15
Table 12-10 Annual Indirect Pollutant Loads to Surface Waters from Animal
Feeding Operations With More Than 300 Animal Units 12~16
Table 13-1. Threshold 1 NWQIs for Beef (Includes Heifers) 13-16
Table 13-2. Threshold 1 NWQIs for Dairy I3"47
Table 13-3. Threshold 1 NWQIs for Veal I3'!8
Table 13-4. Threshold 1 NWQIs for Swine • - • • • • I3'19
Table 13-5. Threshold 1 NWQIs for Chickens I3'20
Table 13-6. Threshold 1 NWQIs for Turkeys • I3'21
Table 13-7. Threshold 2 NWQIs for Beef (Includes Heifers) I3'22
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Table 13-8. Threshold 2 NWQIs for Dairy 13-23
Table 13-9. Threshold 2 NWQIs for Veal , 13-24
Table 13-10. Threshold 2 NWQIs for Swine 13-25
Table 13-11. Threshold 2 NWQIs for Chickens 13-26
Table 13-12. Threshold 2 NWQIs for Turkeys 13-27
xix
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LIST OF FIGURES
Figure 6-1. Manure Characteristics that Influence Management Options 6-1
Figure 8-1. High Rise Hog Building g_25
Figure 8-2. Manure. Scraped and Handled as a Solid on a Paved Lot Operation 8-47
Figure 8-3. Fed Hogs in Confined Area with Concrete Floor and Tank Storage Liquid Manure
Handling 3.59
Figure 8-4. Cross Section of Anaerobic Lagoons 8-57
Figure 8-5. Cross Section of Waste Storage Pond 8-58
Figure 8-6. Aboveground Waste Storage Tank (from USDA NRCS, 1996) 8-62
Figure 8-7. Roofed Solid Manure Storage (from USDA NRCS, 1996) 8-64
Figure 8-8. Cpncrete Pad Design g_67
Figure 8-9. Trickling Filter ; ; _ 3.92
Figure 8-10. Fluidized Bed Incinerator g_97
Figure 8-11. Schematic of Typical Treatment Sequence Involving a Constructed Wetland 8-100
Figure 8-12. Schematic of a Vegetated Filter Strip Used To Treat AFO Wastes 8-102
Figure 8-13. Example Procedure for Determining Land Needed for Manure Application 8-161
Figure 8-14. Example Calculations for Determining Manure Application Rate 8-162
Figure 8-15. Schematic of a Center Pivot Irrigation System 8-177
Figure 11-1. Model Swine Farms •., •. n_j
Figure 11-2. Model Broiler and Layer Farms - 1 i_io
Figure 11-3. Model Turkey Farm 11-12
Figure 11-4, Model Dairy Farms 11-16
Figure 11-5. Model Beef Farm H-19
Figure 11-6. Model Veal Farm 11-21
Figure 11-7. Sample Calculation of Manure and Nutrient Production at Model Farm 11-27
Figure 12-1. Data Used to Develop Sample Farms and the Scale of the Data Sources 12-6
Figure 12-2. Distribution of Animal Sectors by AFO Region 12-7
Figure 12-3. Overview of Methodology Used to Estimate Nutrient, Pathogen, and Metal Loads .12-9
Figure 13-1. Air Emission From Animal Feeding Operations 13.3
Figure 13-2. Basic Nitrogen Cycle ; 13.3
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CHAPTER 1
INTRODUCTION AND LEGAL AUTHORITY
1.0 INTRODUCTION AND LEGAL AUTHORITY
This chapter presents an introduction to the regulations being revised for the concentrated animal
feeding operations (CAFOs) industry and describes the legal authority that the U.S
Environmental Protection Agency (EPA) has to revise these regulations. Section 1.1 describes
the Clean Water Act; Section 1.2 reviews the Pollution Prevention Act; and Section 1.3 describes
the Regulatory Flexibility Act.
I-1 Clean Water! Act TCWA)
The Federal Water Pollution Control Act Amendments of 1972 established a comprehensive
program to "restore and maintain the chemical, physical, and biological integrity of the Nation's
waters" (Section 101(a)). The CWA gives EPA the authority to regulate point source discharges
(including CAFOs) into waters of the United States through the National Pollutant Discharge
Elimination System (NPDES) permitting program. Under the CWA, EPA issues effluent
limitations guidelines, pretreatment standards, and new source performance standards for point
sources, other than publicly owned treatment works (POTWs). Direct dischargers must comply
with effluent limitations in NPDES permits, while indirect dischargers must comply with
pretreatment standards. The remainder of this section describes the NPDES and effluent
limitations guidelines and standards, as they apply to the CAFOs industry.
On October 30,1989, Natural Resources Defense Council, Inc., and Public Citizen, Inc filed an
action against EPA in which they alleged, among other things, that EPA had failed to comply
with CWA Section 304(m). Natural Resources Defense Council, Inc., et al v Reilly Civ No
89-2980 (RCL) (D.D.C.). Plaintiffs and EPA agreed to a settlement of that action in a consent
decree entered on January 31, 1992. The consent decree, which has been modified several times
established a schedule by which EPA is to propose and take final action for eleven point source '
categones.identified by name in the decree and for eight other point source categories identified
only as new or revised rules, numbered 5 through 12. After completing a preliminary study of
the feedlots industry under the decree, EPA selected the swine and poultry portion of the feedlots
industry as the subject for New or Revised Rule #8, and the beef and dairy portion of that
industry as the subject for New or Revised Rule #9. Under the decree, as modified the
Administrator was required to sign a proposed rule for both portions of the feedlots industry on
or before December 15,2000, andmust take final action on that proposal no later than December
15, 2002. As part of EPA's negotiations with the plaintiffs regarding the deadlines for this
rulemaking, EPA entered into a settlement agreement dated December 6, 1999, under which EPA
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agreed, by December 15,2000, to also propose to revise the existing NPDES permitting
regulations under 40 CFR Part 122 for CAFOs. EPA also agreed to perform certain evaluations,
analyses, or assessments and to develop certain preliminary options in connection with the
proposed CAFO rules. (The Settlement Agreement expressly provides that nothing in the
Agreement requires EPA to select any of these options as the basis for its proposed rule.)
1.111 National Pollutant Discharge Elimination System (NPDES)
The NPDES permit program regulates the discharge, of pollutants from point sources to waters of
the United States. The term "point source" is defined in the Clean Water Act (Section 502(14))
as a discernible, confined, and discrete conveyance from which pollutants are or may be •
discharged. CAFOs are explicitly defined as point sources in Section 502(14).
EPA promulgated the current NPDES regulations for CAFOs in the mid-1970s (see 41 F.R.
11458, March 18,1976). Changes to the NPDES regulations for CAFOs are discussed in Section
9.
1.1.2 Effluent Limitations Guidelines and Standards
EPA promulgated effluent limitations guidelines and standards for the Feedlots Point Source
Category in 1974 (40 CFR Part 412) (see 39 F.R. 5704, February 14,1974). EPA is proposing to
revise these regulations as discussed in Section 2.2.
Effluent limitations guidelines and standards for CAFOs are being proposed under the authority
of Sections 301,304,306,307,308,402, and'SOl of the CWA, 33 U.S.C. 1311,1314,1316,
1317,1318,1342, and 1361. Effluent limitations guidelines and standards are summarized
briefly below for direct and indirect dischargers.
Direct Dischargers
• Best Practicable Control Technology Currently Available (BPT) (304(b)(l) of the CWA)
- In the guidelines for an industry category, EPA defines BPT effluent limits for
conventional, toxic, and non-conventional pollutants, hi specifying BPT, EPA looks at a
number of factors. EPA first considers the cost of achieving effluent reductions in relation
to the effluent reduction benefits. The Agency also considers the age of the equipment
and facilities, the processes employed;and any required process changes, engineering
aspects of the control technologies, non-water quality environmental impacts (including
energy requirements), and such other factors as the Agency deems appropriate (CWA
304(b)(l)(B)). Traditionally, EPA establishes BPT effluent limitations based on the
average of the best performances of facilities within the industry of various ages, sizes,
processes, or other common characteristics. Where existing performance is uniformly
inadequate, EPA may require higher levels of control than currently in place in an
industrial category if the Agency determines that the technology can be practically
applied.
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Best Available Technology Economically Achievable (BAT) (304(b)(2) of the CWA) - In
general, BAT effluent limitations represent the best existing economically achievable
performance of direct discharging plants in the industrial subcategory or category. The
factors considered in assessing BAT include the cost of achieving BAT effluent
reductions, the age of equipment and facilities involved, the processes employed,
engineering aspects of the control technology, potential process changes, non-water
quality environmental impacts (including energy requirements), and such factors as the
Administrator deems appropriate. The Agency retains considerable discretion in
assigning the weight to be accorded to these factors. An additional statutory factor
considered in setting BAT is economic acbievability. Generally, the achievability is
determined on the basis of the total cost to the industrial subcategory and the overall
effect of the rule on the industry's financial health. BAT limitations may be based on
effluent reductions attainable through changes in a facility's processes and operations. As
with BPT, where existing performance is uniformly inadequate, BAT may be based on
technology transferred from a different subcategory within an industry or from another
industrial! category. BAT may be based on process changes or internal controls, even
when these technologies are not common industry practice.
Best Conventional Pollutant Control Technology (BCT) (304(b)(4) of the CWA) - The
1977 amendments to the CWA required EPA to identify effluent reduction levels for
conventional pollutants associated with BCT technology for discharges from existing
industrial point sources. BCT is not an additional limitation, but replaces Best Available
Technology (BAT) for control of conventional pollutants. In addition to other factors
specified in Section 304(b)(4)(B), the CWA requires that EPA establish BCT limitations
after consideration of a two part "cost-reasonableness" test. EPA explained its
methodolpgy for the development of BCT limitations in July 1986 (51 F.R. 24974).
Section 3p4(a)(4) designates the following as conventional pollutants: biochemical
oxygen demand (BODS), total suspended solids (TSS), fecal coliform, pH, and any
additional pollutants defined by the Administrator as conventional. The Administrator
designated oil and grease as an additional conventional pollutant on July 30,1979 (44
F.R. 44501).
New Source Performance Standards (NSPS) (306 of the CWA) - NSPS reflect effluent
reductions that are achievable based on the best available demonstrated control
technology. New facilities have the opportunity to install the best and most efficient
production processes and wastewater treatment technologies. As a result, NSPS should
represent the greatest degree of effluent reduction attainable through the application of the
best available demonstrated control technology for all pollutants (i.e., conventional,
non-conventional, and priority pollutants). In establishing NSPS, EPA is directed to take
• into consideration the cost of achieving the effluent reduction and any non-water quality
environmental impacts and energy requirements.
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Indirect Dischargers
• Pretreatment Standards for Existing Sources (PSES) (307(b) of the CWA) - PSES are
designed to prevent the discharge of pollutants that pass through, interfere with, or are
otherwise incompatible with the operation of POTWs. The CWA authorizes EPA to
establish pretreatment standards for pollutants that pass through POTWs or interfere with
treatment processes or sludge disposal methods at POTWs. Pretreatment standards are
technology-based and analogous to BAT effluent limitations guidelines for removal of
priority pollutants. EPA retains discretion not to issue such standards where the total
amount of pollutants passing through a POTW is not significant.
The General Pretreatment Regulations, which set forth the framework for the
implementation of categorical pretreatment standards, are found at 40 CFR Part 403.
Those regulations contain a definition of pass-through that addresses localized rather than
national instances of pass-through and establish pretreatment standards that apply to all
domestic dischargers (see 52 F.R. 1586, January 14,1987).
• Pretreatment Standards for New Sources (PSNS) (307(b) of the CWA) - Like PSES,
PSNS are designed to prevent the discharges of pollutants that pass through, interfere
with, or are otherwise incompatible with the operation of POTWs. PSNS are to be issued
at the same time as NSPS. New indirect dischargers have the opportunity to incorporate
into thek facilities the best available demonstrated technologies. The Agency considers
the same factors in promulgating PSNS as it considers in promulgating NSPS. EPA
retains discretion not to issue such standards where the total amount of pollutants passing
through a POTW is not significant.
1.2 Pollution Prevention Act fPPA)
In the Pollution Prevention Act of 1990 (42 U.S.C. 13101 et seq., Pub. Law 101-508, November
5,1990), Congress declared pollution prevention a national policy of the United States. The PPA
declares that pollution should be prevented or reduced at the source whenever feasible; pollution
that cannot be prevented should be recycled hi an environmentally safe manner whenever
feasible; pollution that cannot be prevented or recycled should be treated;, and disposal or other
release into the environment should be chosen only as a last resort and should be conducted hi an
environmentally safe manner. This proposed regulation for animal feeding operations was
reviewed for its incorporation of pollution prevention as part of the Agency effort. Pollution
prevention practices applicable to animal feeding operations are described hi Chapters 4 and 8.
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1.3 Regulatory Flexibility Act (RFA) as Amended by the Small Business Regulatory
Enforcement Fairness Act of 1996 (SBREFA)
In accordance with Section 603 of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.),
EPA prepared an initial regulatory flexibility analysis (IRFA) that examines the impact of the
proposed rule on small entities along with regulatory alternatives that could reduce that impact.
The IRFA (available in Chapter 9 of Economic Analysis of the Proposed Revisions to the
National Pollutant Discharge Elimination System Regulation and the Effluent Guidelines for
Concentrated Animal Feeding Operations) concludes that the economic affect of regulatory
options being considered might significantly impact a substantial number of small livestock and
poultry operations.
As required by Section 609(b) of the RFA, as amended by SBREFA, EPA also conducted
outreach to small entities and convened a Small Business Advocacy Review Panel to obtain the
advice and recommendations of representatives of the small entities that potentially would be
subject to the rule's requirements. Consistent with the RFA/SBREFA requirements, the panel
evaluated the assembled materials and small entity comments on issues related to the elements of
the IRFA. Participants included representatives of EPA, the Small Business Administration
(SBA), and the Office of Management and Budget (OMB). Participants from me farming
community included small livestock and poultry producers as well as representatives of lie major
commodity and agricultural trade associations. A summary of the panel's activities and
recommendations is provided in the Final Report of the Small Business Advocacy Review Panel
on EPA's Planned Proposed Rule on National Pollutant Discharge Elimination System (NPDES)
and Effluent Limitations Guideline (ELG) Regulations for Concentrated Animal Feeding
Operations (April 7,2000). This document is included in the public record.
1-5
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CHAPTER 2
SUMMARY AND SCOPE OF PROPOSED REGULATION
i
2-0 SUMMARY AND SCOPE OF PROPOSED REGULATION
The proposed regulations described in this document include revisions of two regulations that
ensure manure, wastewater, and other process waters for concentrated animal feeding operations
(CAFOs) do not iimpair water quality. These two regulations are the National Pollutant
Discharge Elimination System (NPDES) described in Section 2.1 and the Effluent Limitations
Guidelines and Standards for feedlots (beef, dairy, swine, and poultry) described in Section 2.2,
which establish the technology-based standards that are applied to CAFOs. Both regulations
were originally promulgated in the 1970s. EPA proposes revisions to these regulations to
address changes that have occurred hi the animal industry sectors over the last 25 years, to clarify
and improve implementation of CAFO permit requirements, and to improve the environmental
protection achieved under these rules.
2-1 National Pollutant Discharge Elimination System (NPDES^
As noted in Section 1, CAFOs are "point sources" under the Clean Water Act. The regulation at
40 CFR 122.23 specifies which animal feeding operations are CAFOs and therefore are subject
to the NPDES program on that basis.
2.1.1 Applicability of the Proposed Regulation
The existing NPDES regulation uses the term "animal unit," or AU, to identify facilities that are
CAFOs. The term AU is a metric unit established in the 1970 regulations that attempted to
equate the characteristics of the wastes produced by different animal types. The existing
regulation defines facilities with 1,000 animal units or more as CAFOs. The regulation also
states that facilities with 300 to 1,000 animal units are CAFOs if they meet certain conditions.
The proposed rule presents two alternatives for how'to structure the revised NPDES program for
CAFOs, each of which offers comparable environmental benefits but differs in the administrative
approach. Additional approaches considered but not proposed are described in Section 9. The
first alternative proposal is a two-tier applicability structure that simplifies the definition of
which facilities are CAFOs by establishing a single threshold for each animal sector. This
proposal establishes a single threshold at the equivalent of 500 AU, above which operations are
defined as CAFOs, and below which facilities become CAFOs only if designated by the permit
authority. The 500 AU equivalent for each animal sector is as follows:
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500 cattle (excluding mature dairy cattle or veal calves);
500 veal calves;
350 mature dairy cattle (whether milked or dry);
1,250 mature swine weighing over 55 pounds;
5,000 immature swine weighing 55 pounds or less;
50,000 chickens;
27,500 turkeys;
2,500 ducks;
250 horses; and/or
5,000 sheep or lambs.
The second alternative retains the three-tier applicability structure of the existing regulation:
1) All operations with 1,000 AUs or more are defined as CAFOs.
2) Operations with 300 to 1,000 AU would be CAFOs only if they meet certain
conditions or if designated by the permitting authority.
3) Operations with fewer than 300 AU would be CAFOs only if designated by the
permitting authority.
All facilities with 300 to 1,000 AU must either certify that they do not meet the conditions for
being defined as a CAFO or else apply for a permit. The 300 to 1,000 AU equivalent numbers of
animals for each sector are presented in Table 2-1. .
Table 2-1. Number of Animals by Sector for 300 and 1,000 AU Equivalents
Animal Type
Cattle (excluding mature dairy or veal)
Veal
Mature dairy cattle
Swine weighing more than 55 pounds
Swine weighing 55 pounds or less
Chickens
Turkeys
Ducks
Horses
Sheep or lambs
1,000 ATI Equivalent
(Number of Animals)
1,000
1,000
700
2,500
10,000
100,000
55,000
5,000
500
10.000
300 AU Equivalent „
(Number of Animals)
300
300
200
750
3,000
30,000
16,500
1,500
150
3.000
The proposed rule also includes all types of poultry operations, regardless of manure handling
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system or watering system, and stand-alone immature swine and heifer operations.
2.1.2 Summaiy of Proposed Revisions to NPDES Regulations
EPA proposes to simplify the criteria for being designated as a CAFO by eliminating two specific
criteria that have proven difficult to implement: the "direct contact" criterion and the "man-made
device" criterion; however, the proposal retains the existing requirement for the permitting
authority to consider a number of factors to determine whether the facility is a significant
contributor of pollution to the waters of the United States. The proposal also retains the
requirement for an on-site inspection in order to make this determination. EPA proposes to
clarify its authority to designate facilities in states with NPDES authorized programs.
EPA also proposes to eliminate the 25-year, 24-hour storm event permit exemption and to
impose a duty to apply for an NPDES permit. Under the current rule, an operation that otherwise
meets the definition of a CAFO but that discharges only in the event of a 25-year, 24-hour storm
is exempt from being defined as a CAFO. Currently, there are many operations that believe that
they do not need to apply for a permit on this basis. EPA believes, however, that many operators
have underestimated their discharges of manure and wastewater from the feedlot, manure storage
areas, wastewater containment areas, and land application areas and have not applied for a permit
when, in fact, they needed one. Under this proposal, all operations meeting the definition of a
CAFO under either of the two applicability alternatives described in Section 2.1.1 would be
required to apply for a permit. However, under this proposal, if the operator could demonstrate
to the permitting authority that the facility has no potential to discharge, then the operator could
request not to be issued a permit by the permitting authority.
Under the two-tier applicability structure, EPA estimates that approximately 26,000 operations
will be required to apply for a NPDES permit. Under the three-tier applicability structure, EPA
estimates that approximately 13,000 operations will be required to apply for a permit, and an
additional 26,000; operations could either certify that they are not a CAFO or apply for a permit.
Under the existing regulation, EPA estimates that about 12,000 facilities should be permitted, but
only 2,530 have actually applied for a permit.
Under this proposal, the definition of a CAFO would explicitly include the production area
(animal confinement area, manure storage area, waste containment area) as well as the land
application area that is under the control of the CAFO owner or operator. Recent industry trends
show more and larger feedlots with less cropland for application of manure, often resulting in
significant manure excesses. EPA is concerned that as a result of these trends, manure is taking
on the characteristic of a waste and is being applied to land in excess of agricultural uses, causing
runoff or leaching into waters ;of the United States. The permit will address practices at the
production area as well as the land application area, and will impose certain other record keeping
requirements withregard to transfer of manure off site.
EPA further proposes to clarify that entities which exercise "substantial operational control" over
the CAFO would be required to obtain a permit along with the CAFO operator. This provision is
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intended to address the increasing trend towards specialized animal production under contract
with processors, packers, and other such integrators. Especially in the swine and poultry sector,
the processor provides the animals, feed, medication, specifies growing practices, or a
combination of these. This trend has resulted in growing concentrations of excess manure
beyond agricultural needs in certain geographic areas. By making both parties liable for
compliance with the terms of the permit as well as responsible for the excess manure generated
by CAFOs, EPA intends that manure will be managed to prevent environmental harm.
In summary, the following components describe the general revisions that EPA is proposing to
make to the NPDES regulations: :
• Require the CAFO operator to develop a Permit Nutrient Plan for
managing manure and wastewater at both the production area and
the land application area;
• Require certain record keeping, reporting, and monitoring;
• Revise the definition of an animal feeding operation (AFO) to
clarify coverage^ of winter feeding operations;
• Eliminate the term "animal unit" and eliminate the mixed-animal •
type calculation to simplify the regulation;
• Clarify the applicability of the regulation where there is ground
water with a direct hydrological connection to surface water;
• Clarify how the exemptions in the Clean Water Act for storm
water-related discharges relate to runoff associated with the land
application of manure both at the CAFO and off site;
• Reiterate the existing CWA requirements that apply to dry weather
discharges at AFOs;
• Require permit authorities to include special conditions in permits
to:
- require retention of a permit until proper facility closure;
- establish the method for operators to calculate the allowable
manure application rate;
• -specify restrictions on application of manure and wastewater to
frozen, snow covered, or saturated land to prevent impairment of
water quality;
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- address risk of contamination via ground water with a direct
hydrological connection to surface water;
- require that the CAFO operator obtain a certification from off-site
recipients of CAFO manure that the recipients will properly
manage the manure; and
- establish design standards to account for chronic storm events.
2-2 Effluent Limitations Guidelines and Standards
The proposed effluent limitations guidelines and standards regulations will establish the Best
Practicable Control Technology (BPT), Best Conventional Pollutant Control Technology (BCT)
and the Best Availability Technology (BAT) limitations as well as New Source Performance
Standards (NSPS) on discharges from the production area as well as the land application areas at
CAFOs. Section 2.2.1 describes the applicability of the proposed regulation; Section 222
summarizes proposed revisions to effluent limitations guidelines and standards.
2.2.1 Applicability of the Proposed Regulation
EPA has subcategorized the CAFOs Point Source Category based primarily on animal type See
Section 5 for a discussion of the basis considered for subcategorization. These subcategories
listed and described in Table 2-2.
are
Subpart:
Table 2-2. Basis Considered for Subcategorization of CAFOs
iliilHl^Sl^^
Horses, Sheep, and Lambs
CAFOs under 40 CFR 122.23 which confine horses,
sheep, or lambs
B
Ducks
CAFOs under 40 CFR 122.23 which confine ducks
C
Beef and Dairy
CAFOs under 40 CFR 122.23 which confine mature
dairy cows (either milking or dry) and cattle other
than mature dairy or veal
D
Swine, Poultry, and Veal
CAFOs under 40 CFR 122.23 with swine, each
weighing 55 pounds or more; swine, each weighing
less than 55 pounds; veal calves; chickens, and/or
turke\
EPA is not proposing to revise the effluent guidelines requirements or the applicability for
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subcategory A (horses, sheep, and lambs) and subcategory B (ducks), even though the definition
of a CAFO for these subcategories has changed.
The effluent guidelines requirements for subcategory C (beef and dairy) and subcategory D
(swine, poultry, and veal) apply to any operations that are defined as CAFOs under either the
two-tier or three-tier applicability structure of the NPDES regulation described in Section 2.1.
Under the two-tier applicability structure, the requirements apply to all operations defined as
CAFOs having at least as -many animals as listed below:
500 cattle, (excluding mature dairy cattle or veal calves);
500 veal calves;
350 mature dairy cattle (whether milked or dry);
1,250 swine weighing over 55 pounds;
5,000 swine weighing 55 pounds or less;
50,000 chickens; or
27,500 turkeys.
Under the three-tier applicability structure, the requirements apply to all operations defined as
CAFOs having at least as many animals as listed below:
• • 300 cattle (excluding mature dairy cattle or veal calves);
• 300 veal calves;
200 mature dairy cattle (whether milked or dry);
750 swine weighing over 55 pounds;
3,000 swine weighing 55 pounds or less;
30,000 chickens; or
16,500 turkeys.
EPA is proposing several changes to the applicability of the existing regulation:
1) Chickens - Chickens refer to laying hens,|pullets, broilers, breeders, and other meat-type
chickens. EPA is proposing to clarify the effluent guidelines to ensure coverage of broiler and
laying hen operations that do not use liquid ipanure handling systems or continuous overflow
watering. EPA thus proposes to regulate chicken operations regardless of the type of watering
system or manure handling system used.
2) Mixed Animal Types - EPA proposes to eliminate provisions hi the existing regulation that
apply to mixed animal operations. As discussed in Section 9, this will simplify the regulation.
Note that once a facility is defined as a CAFO, the manure associated with all animals in
confinement would be subject to NPDES requirements.
3) Immature Animals - EPA proposes to apply national technology-based standards to swine
nurseries and to operations that confine immature dairy cows or heifers apart from the dairy.
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EPA proposes to include stand-alone heifer operations under the subcategory C (Beef and Dairy).
Any feedlot that confines heifers along with cattle for slaughter would also be subject to the
subcategory C requirements. Furthermore EPA proposes to include swine facilities that confine
swine weighing under 55 pounds each under the subcategory D.
4) Veal Operations - EPA proposes to establish a new subcategory that applies to the production
of veal cattle. Veal production is included in the existing regulation as slaughter steer. However,
veal production practices and wastewater and manure handling are very different from the
practices used at beef feedlots, and meet a different BAT performance standard than beef
feedlots. Therefore EPA proposes to establish a separate subcategory for veal.
2.2.2 Summary of Proposed Revisions to Effluent Limitations Guidelines and Standards
CAFOs in the beef, dairy, swine, poultry, and veal subcategories that meet the definition of a
CAFO under either the two-tier or three-tier applicability structure of NPDES would be required
under this rule to comply with the effluent limitations guidelines and standards. The proposed
guidelines establish BPT, BCT, BAT, and NSPS by requiring effluent limitations and standards
and specific best management practices that ensure that manure storage and handling systems are
inspected and maintained adequately as described in the following subsections. EPA evaluated
the following eight regulatory options for the proposed guidelines:
• Option 1: Nitrogen-Based Application;
• Option 2: Phosphorus-Based Application;
• Option 3: Phosphorus-Based Application + Ground Water
Protection;
• Option 4: Phosphorus-Based Application + Ground Water
Protection + Surface Water Protection;
• Option 5: Phosphorus-Based Application + Drier Manure;
• Option 6: Phosphorus-Based Application + Anaerobic Digestion;
• Option 7: Phosphorus-Based Application + Timing Restrictions;
and
• Option 8: Phosphorus-Based Application + Minimized Potential
for Discharge.
These options are described-in detail in Section 10.0.
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2.2.2.1 Best Practicable Control Technology (BPT)
EPA is proposing BPT limitations based on Option 2 for the beef and dairy subcategories and the
swine, poultry, and veal subcategories.. Table 2-3 shows the technology basis of BPT for these
subcategories. Under BPT, EPA proposes zero discharge from the production area with an
overflow due to catastrophic or chronic storms allowed. If the CAPO uses a liquid manure
handling system, it must have a liquid storage structure or lagoon that is designed, constructed,
and maintained to capture all process wastewater and manure, plus all of the storm water runoff
from a 25-year, 24-hour storm.
BPT includes specific requirements on the application of manure and wastewater to land that is
owned or under the operational control of the CAFO. CAFOs are required to apply their manure
at a rate calculated to meet the requirements of the crop for either nitrogen or phosphorus,
depending on the soil conditions for phosphorus. Livestock manure tends to be phosphorus-rich,
meaning that if manure is applied to meet the nitrogen requirements of a crop, then the
phosphorus is being applied at rates higher than needed by the crop. Repeated application of
manure on a nitrogen basis may build up phosphorus levels in the soil, and result in saturation,
thus contributing to the contamination of surface waters. Therefore, EPA also proposes that
manure must be applied to cropland at rates not to exceed the crop requirements for nutrients and
the ability of the soil to absorb any excess phosphorus.
BPT establishes specific record keeping requirements associated with ensuring the limitations are
met for the production area and that the application of manure and wastewater is done in
accordance with land application requirements;. EPA also proposes to require the CAFO to
maintain records on any excess manure that is transported off site. The CAFO must provide the
recipient with information on the nutrient content of the manure transferred and the CAFO must
keep these records on site.
2.2.2.2 Best Control Technology (BCT)
EPA proposes BCT equivalent to BPT for the beef and dairy subcategories and the swine,
poultry, and veal subcategories. Table 2-3 shows the technology bases of BCT for these
subcategories.
2.2.2.3 Best AvaUable Technology (BAT)
EPA proposes BAT limitations based on Option 3 for the Beef and Dairy Subcategories and
Option 5B for the Swine, Poultry, and Veal Subcategories. Table 2-1 shows the technology
bases of BAT for these subqategories.
BAT limitations for the beef and dairy subcategories are based on the proposed BPT technology
requirements with the additional requirement to achieve zero discharge via ground water beneath
the production area, whenever the ground water has a direct hydrological connection to surface
water. The proposed BAT requirements for the swine, poultry, and veal subcategories eliminate
,2-S
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the allowance for overflow in the event of a chronic or catastrophic storm. CAFOs in these
subcategones typically house their animals under roof instead of in open areas, thus avoiding or
minimizuig contaminated storm water and the need to contain storm water.
2.2.2.4 New Source Performance Standards (NSPS)
EPA proposes NSPS based on Option 3 for the beef and dairy subcategories and a combination
ol Option 3 and Option 5B for the swine, poultry, and veal subcategories. Table 2-3 shows the
technology bases of NSPS for these subcategories.
EPA proposes to revise NSPS based on the same technology requirements as BAT for the beef
and dairy subcategones. For the swine, poultry, and veal subcategories, EPA added to the BAT
requirements that there be no discharge of pollutants through ground water beneath the
production area, when the ground water has a direct hydrological connection to surface water.
Both the BAT and NSPS requirements have the same land application and record keeping
requirements as proposed for BPT.
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CHAPTER 3
DATA COLLECTION ACTIVITIES
3.0 DATA COLLECTION ACTIVITIES
EPA coUected and evaluated data from a variety of sources during the course of developing the
proposed effluent limitations guidelines and standards for the concentrated animal feeding
operations (CAFO) industry. These data sources include EPA site visits, industry trade
associations, the U.S. Department of Agriculture, published literature, previous EPA Office of
Water studies of the Feedlots Point Source Category, and other EPA studies of animal feeding
operations. Each of these data sources is discussed below, and analyses of the data collected by
EPA are presented throughout the remainder of this document.
3.1 Summary
Site Visit Program
The Agency conducted approximately 1 10 site visits to collect information about animal feeding
operations (AFOs) and waste management practices. Specifically, EPA visited swine, poultry
dairy, beef, and veal AFOs throughout the United States. In general, the Agency visited a wide
range of AFOs, including those demonstrating centralized treatment or new and innovative
technologies. The majority of facilities were chosen with the assistance of the following industry
trade associations: • *» j
• National Pork Producers Council;
United Egg Producers and United Egg Association;
National Turkey Federation;
National Cattlemen's Beef Association;
• National Milk Producers Federation; and
• Western United Dairymen.
EPA also received assistance from environmental groups, such as the Natural Resources Defense
Council and the Clean Water Network. The Agency contacted university experts state
cooperatives and extension services, and state and EPA regional representatives when identifying
facilities for site visits. EPA also attended USDA-sponsored farm tours, as well as industry
academic, and government conferences.
Table 3-1 summanzes the number of site visits EPA conducted by animal industry sector, site
locations, and size of animal operations.
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Table 3-1. Number of Site Visits Conducted by EPA for the
Various Animal Industry Sectors
Animal
Swine
Poultry
Dairy
Beef
Number of Site
30
6 (broiler)
12 (layer)
6 (turkey)
25
30
3
Locations)
NC, PA, OH, IA, MN, TX, OK, UT
GA, AR, NC, VA, WV, MD, DE, PA,
OH,IN,WI
;PA,FL,CA,WI,CO
TX, OK, KS, CO, CA, IN, NE, IA
IN
" > '
Size of Operations
900 - 1 million head
20,000 - 1 million
birds
40 - 4,000 cows
500 - 120,000 head
500 - 540 calves
In general, the Agency considered several factors when identifying representative facilities for
site visits, including the following: •
\
• Type of animal feeding operation;
• Location; f
• Feedlot size; and :
• Current waste management practices.
Facility-specific selection criteria are contained in site visit reports (SVRs) prepared for each
facility visited by EPA. The SVRs are contained in the administrative record for this rulemaking.
During the site visits, EPA typically collected the following types of information:
• , General facility information, including size and age of facility, number of
employees, crops grown, precipitation information, and proximity to nearby
waterways;
Animal operation data, including flock or herd size, culling rate, and method for
" disposing dead animals;
Description of animal holding areas, such as barns or pens, and any central areas,
such as milking centers;
i
Manure collection and management information, including the amount generated,
removal methods and storage location, disposal information, and nutrient content;
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Wastewater collection and management information, including the amount
generated, runoff information, and nutrient content;
Nutrient management plans and any best management practices (BMPs); and
Available wastewater discharge permit information.
ite-Spedfic fcfcmafcm. » documented in the SVRs for each
3.2 Industry Trad* Associations
EPA contacted the following industry trade associations during the development of the proposed
National Pork Producers Council (NPPQ. NPPC is a marketing organization and trade
association made ;up of 44 affiliated state pork producer associations. NPPC's purpose is to
increase the quality, production, distribution, and sales of pork and pork products.
United Egg Producers and United Fre Associate (rmP/rre A) UEP/UEA promotes the egg
*n*!S I" ^ ?°T^raf PrfCe discovery' Production and marketing information, unified
industry leadership, USDA relationships, and promotional efforts.
National Turkey Federation (NTF). NTF is the national advocate for all segments of the turkey
industry, providing services and conducting activities that increase demand for its members'
products. ,
National Chicketi To^nl (NfV). NCC represents the vertically integrated companies that '
produce and process about 95 percent of the chickens sold in the United States. Hie association
provides consumer education, public relations, and public affairs support, and is working to seek
a positive regulatory, legislative, and economic environment for the broiler industry.
National Cattlemen's Beef Association (NCR A). NCBA is a marketing organization and trade
association for cattle fanners and ranchers, representing the beef industry.
National Milk Producers Federation (NMPF). NMPF is involved with milk quality and
standards, annual health and food safety issues, dairy product labeling and standards and
legislation affecting the dairy industry.
American Veal Association (AVA). AVA represents the veal industry, and advances the
industry s concerns in the legislative arena, coordinates production-related issues affecting the
industry, and handles other issues relating to the industry.
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Western United Dairymen fWUDX WUD, a dairy organization in California, promotes
legislative and administrative policies and programs for the industry and consumers.
Professional Dairy Heifer Growers Association (PDHGAX PDHGA is'an association of heifer
growers who are dedicated to growing high-quality dairy cow replacements. The association
offers educational programs and professional development opportunities, provides a
communication network, and establishes business and ethical standards for the dairy heifer
grower industry. ;
All of the above organizations, along with several of their state affiliates, assisted EPA's efforts
to understand the industry by helping with site-visit selection, submitting supplemental data, and
reviewing descriptions of the industry and waste management practices. These organizations
also participated in and hosted meetings-with EPA for the purpose of exchanging information
with the Agency. EPA also obtained copies of membership directories and conference
proceedings, which were used to identify contacts and obtain additional information on the:
industry. .;
1* TT.S. Department of Agriculture (USDA)
EPA obtained data from several agencies within the USDA, including the National Agricultural
Statistics Service (NASS), the Animal and Plant Health Inspection Service (APHIS), Natural
Resources Conservation Service (NRCS), and the Economic Research Service (ERS) in order to
better characterize the AFO industry. The collected data include statistical survey information
and published reports. Data collected from each agency are described below.
3.3.1 National Agricultural Statistics Service (NASS)
NASS is responsible for objectively providing important, usable, and accurate statistical
information and data support services of structure and activities of agricultural production in the
United States. Each year NASS conducts hundreds of surveys and prepares reports covering
virtually every facet of U.S. agricultural publications. The primary source of data is the animal
production facility. NASS collects voluntary information using mail surveys, telephone and 111-
person interviews, and field observations. NASS is also responsible for conducting a Census of
Agriculture, which is currently performed once every 5 years; the last census occurred in 1997.
EPA gathered information from the following published NASS reports:
Hogs and Pigs: Final Estimates 1993 - 1997;
Chickens and Eggs: Final Estimates 1994 - 1997;
Poultry Production and Value: Final Estimates 1994 - 1997;
Cattle: Final Estimates 1994 - 1998;
Milking Cows and Production: Final Estimates 1993 - 1997; and
1997 Census of Agriculture.
The information EPA collected from these sources is summarized below.
! 3-4
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'Hoss and Piss: Final Estimates 1993 - 1997
EPA used data from this report to augment the swine industry profile. The report presents
inventory, market hogs, breeding herd, and pig crops. Specifically, the report provides the
number of farrowings, sows, and pigs per litter. This report presents the number of operations
with hogs; however, EPA did not use this report to estimate farm counts because the report
provided limited data. Instead, EPA used the 1997 Census of Agriculture data to estimate farm
counts, as discussed later in this section.
Chickens and Eggs: Final Estimates 1994 - 1997
EPA used data from this report to augment the poultry industry profile. The report presents
national and staie-level data for the-top-producing states on chickens and eggs, including the
number laid and production for 1994 through 1997.
Poultry Production and Value: Final Estimates 1994 - 1997
EPA also used data from this report to augment the poultry industry profile. The report presents
national and state-level data for the top producing states on production (number and pounds
produced/raised), price per pound or egg, and value of production of broilers, chickens, eggs, and
turkeys for 1994 through 1997.
Cattle: Final Estimates 1994 - 1998
EPA used data from this report to augment the beef industry profile. The report provides the
number and population estimates for beef feedlots that have a capacity of over 1,000 head of
cattle, grouped by size and geographic distribution. This report provides national and state-level
data for the 13 top-producing beef states, which include the number of feedlots, cattle inventory,
and number of cattle sold per year by size class. The report also provides the total number of
feedlots that have a capacity of fewer than 1,000 head of cattle, total cattle inventory, and number
of cattle sold per year for these operations. EPA did not use this report to estimate farm counts
because the report provided limited data. Instead, EPA used the 1997 Census of Agriculture data
to estimate farm counts, as discussed later in this section.
Milking Cows and Production: Final Estimates 1993 - 1997
EPA used data from this report to augment the dairy industry profile. The report presents
national and state-level estimates of dairy cattle inventory and the number of dairy operations by
size group. This particular report presents data for all dairy operations with over 200 mature
dairy cattle in one size class. EPA did not use this report to estimate farm counts because the
report provided limited data. Instead, EPA used the 1997 Census of Agriculture data to estimate
.farm counts, as discussed below.
1997 Census of Agriculture
The Census of Agriculture is a complete accounting of U.S. agricultural production and is the
only source of uniform, comprehensive agricultural data for every county in the nation. The
census is conducted every 5-years. Prior to 1997, the Bureau of the Census conducted this
activity. Starting with the 1997 Census of Agriculture, the responsibility passed to USD A
NASS. The census includes all farm operations from which $1,000 or more of agricultural
3-5 . . • '
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products are produced and sold. The most recent census occurred in late 1997 and is based on
calendar year 1997 data. i
The census collects information relating to land use and ownership, crops, livestock, and poultry.
This database is maintained by USDA; data used for this analysis were compiled with the
assistance of staff at USDA NASS. (USDA periodically publishes aggregated data from these
databases and also compiles customized analyses of the data for members of the public and other
government agencies. In providing such analyses, USDA maintains a sufficient level of
aggregation to ensure the confidentiality of an|r individual operation's activities or holdings.)
Several size groups were developed to allow tabulation of farm counts by farm size using
different criteria than those used in the published 1997 Census of Agriculture. EPA developed
algorisms to define farm size in terms of capacity, or number of animals likely to be found on
the farm at any given time. To convert sales of hogs and pigs and feeder pigs into an inventory,
EPA divided total sales by the number of groups of pigs likely to be produced and sold in a given
year. EPA estimates that the larger grow-finish farms produce 2.8 groups of pigs per year.
Farrow-finish operations produce 2.0 groups oifpigs per year. Nursery operations produce up to
10 groups per year. Data used to determine the groups of pigs produced per year were obtained
from a survey performed by USDA APHIS (1999).
For beef operations, EPA estimates the larger feedlots produce up to 3.5 groups of cattle per year,
while the smaller operations produce only 1 to 1.5 groups per year (ERG, 2000b). The newly
aggregated data better depict the size and geographic distribution of AFOs needed for EPA's
analysis, particularly smaller beef feedlots (fewer than 1,000 head capacity) and larger dairi.es
(more than 200 mature dairy cattle). EPA used the census data to gather more details on the
larger dairies, such as the number of operations and number of head for additional size classes
(200 to 499, 500 to 999, and more than 1,000 head).
USDA NRCS also compiled and performed analyses on census data that EPA used for its
analyses. These data identify the number of feedlots, their geographical distributions, and the
amount of cropland available to land apply animal manure generated from their confined feeding
operations (based on nitrogen and phosphorus availability relative to crop need). EPA used these
estimates to identify feedlots that may not own sufficient land to apply all of the animal manure
to the land. EPA used the results of this analysis to estimate the number of AFOs that may incur
additional manure transportation costs under the various regulatory options considered under the
proposed rule (see Chapter 10). :
3.3.2 Animal and Plant Health Inspection Service (APHIS)/National Animal Health
Monitoring System (NAHMS)
APHIS provides leadership in ensuring the health and care of animals and plants, improving
agricultural productivity and-competitiveness, and contributing to the national economy and
public health. One of its main responsibilities i|s to enhance the care of animals. In 1983, APHIS
initiated the National Animal Health Monitorinjg System (NAHMS) as an information-gathering
3-6 • •
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program to collect, analyze, and disseminate data on animal health, management and
productivity across the United States. NAHMS conducts national studies to gather data and
5T2?te d*scn$lve statistics and information from data collected by other industry sources
NAHMS has published national study reports for various food animal populations (e.g. swine
dairy cattle). '
EPA garnered information from the following NAHMS reports:
Swine'95 Part I: Reference of 1995 Swine Management Practices;
Swine '95 Part II: Reference of Grower/Finisher Health & Management
Practices;
Layers '99 Parts I and II: Reference of1999 Table Egg Layer Management in the
Lf.S.;
Dairy '96 Part I: Reference of 1996 Dairy Management Practices;
Dairy '96 Part III: Reference of 1996 Dairy Health and Health Management-
Beef Feedlot'95 Parti: Feedlot Management Practices; and
Feedlot '99 Part I: Baseline Reference of Feedlot Management Practices.
EPA also collected information from NAHMS fact sheets, specifically the Swine '95 fact sheets
which describe biosecunty measures, vaccination practices, environmental practices/
management, and antibiotics used in the industry.
Swine '95 Part I: Reference of1995 Swine Management Practices
This report provides references on productivity, preventative and vaccination practices
biosecunty issues, and environmental programs (including carcass disposal). The data were
obtained from a sample of 1,477 producers representing nearly 91 percent of the U.S. hog
inventory from the top 16 pork-producing states. Population estimates are broken down into
farrowing and weiming, nursery; grower/finisher, and sows.
Swine '95 Part II- Reference of Grnwer/Fmiihe.r Health & Management Practices
This report provides additional references on feed and waste management, health and
productivity, marketing, and quality control. The data were collected from 418 producers with
operations having 300 or more market hogs (at least one hog over 120 pounds) and represent
about 90 percent of the target population. NAHMS also performed additional analyses for EPA
that present manure management information for the swine industry by two size classes (fewer
than 2,500 marketed head and more than 2,500 marketed head) and three regions (Midwest
North, and Southeast) (USDA APHIS, 1999).
Layers'99 Parts I and TT- Reference nf 1999 Table Ev? Lover Management in the U S
The Layers '99 study is the first NAHMS national study of the layer industry. Data were
obtained from 15 states, which account for over 75 percent of the table egg layers in the United
States. Part I of this report provides a summary of the study results, including descriptions of
farm sites and flocks, feed, and health management. Part H of this report provides a summary of
biosecunty, facility management, and manure handling.
1 ' 3-7
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Dairy '96 Part I: Reference of 1996 Dairy Management Practices and Dairy '96 Part III:
Reference of 1996 Dairy Health and Health Management
These reports present the results of a survey that was distributed to dairies in 20 major states to
collect information on cattle inventories; dairy herd management practices; health management;
births, illness, and deaths; housing; and biosecurity. The results represent 83 percent of U.S.
milk cows, or 2,542 producers. The reports also provide national data on cattle housing, manure
and runoff collection practices, and irrigation/land application practices for dairies with more
than 200 or fewer than 200 mature dairy cattlej. NAHMS provided the same information to EPA
with the results reaggregated into three size classes (fewer than 500, 500 to 699, and more than
700 mature dairy cattle) and into three regions; (East, West, and Midwest) (ERG, 2000a).
BeefFeedlot '95 Part I: Feedlot Management Practices
This report contains information on population estimates, environmental programs (e.g., ground
water monitoring and methods of waste disposal), and carcass disposal at small and large beef
feedlots (fewer than and more than 1,000 head capacity). The data were collected from 3,214
feedlots in 13 states, representing almost 86 percent of the U.S. cattle-on-feed inventory.
Feedlot '99 Part I: Baseline Reference of Feedlot Management Practices
This report also contains information on population estimates, environmental programs, and
carcass disposal at beef feedlots. The data weire collected from 1,250 feedlots in 12 states,
representing 77 percent of all cattle on feed inthe United States.
333 Natural Resources Conservation Services (NRCS)
NRCS provides leadership hi a partnership effort to help people conserve, improve, and sustain
our natural resources and the environment. NRCS relies on many partners to help set
conservation goals, work with people on the land, and provide assistance. Its partners include
conservation districts, state and federal agencies, NRCS Earth Team volunteers, agricultural and
environmental groups, and professional societies.
NRCS publishes the Agricultural Waste Management Field Handbook, which is an
agricultural/engineering guidance manual that explains general waste management principles,
and provides detailed design information for particular waste management systems. The
handbook reports specific design information a variety of farm production and waste
management practices at different types of feedlots. The handbook also reports runoff
calculations under normal and peak precipitation as well as information on manure and bedding
characteristics. EPA used this information to develop its cost and environmental analyses.
NRCS personnel also contributed technical expertise in the development of EPA's estimates of
compliance costs and environmental assessment framework by providing EPA with estimates of
manure generation in excess of expected crop uptake.
3-8
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3.3.4 Economic Research Service (ERS)
ERS provides economic analyses on efficiency, efficacy, and equity issues related to agriculture,
food, the environment, and rural development to improve public and private decision making.
ERS uses data from the Farm Costs and Returns Survey (FCRS) to examine farm financial
performance (USDA ERS, 1997). This report developed 10 regions that were intended to group
agricultural production into broad geographic regions of the United States: Pacific, Mountain,
Northern Plains, Southern Plains, Lake States, .Corn Belt, Delta, Northeast, Appalachian, and
Southern. EPA further consolidated the 10 sectors into 5 regions in order to analyze aggregated
Census of Agriculture data.
ERS is also responsible for the Agricultural Resource Management Study (ARMS), USDA's
primary vehicle for collection of information on a broad range of issues about agricultural
resource use and costs and farm sector financial conditions. The ARMS_is a flexible data
collection tool wjth several versions and uses. Information is collected via surveys, and it
provides a measure of the annual changes in the financial conditions of production agriculture.
3.4 Literature Sources
EPA performed several Internet and literature searches to identify papers, presentations, and
other applicable materials to use in developing the proposed rule. Literature sources were
identified from library literature searches as well as through EPA contacts and industry experts.
Literature collected by EPA covers such topics as housing equipment, fertilizer and manure
application, general agricultural waste management, air emissions, pathogens, and construction
cost data. EPA used literature sources to estimate the costs of design and expansion of waste
management system components at AFOs. EPA also used publicly available information from
several universities specializing in agricultural research for industry profile information, waste
management and modeling information, and construction cost data, as well as existing computer
models, such as the FarmWare Model that was developed by EPA's AgStar program.
3.5 References
ERG. 2000a. Development of Frequency Factors for the Beef and Dairy Cost Model.
Memorandum from Eastern Research Group, hie. to the Feedlots Rulemaking Record.
December 11,2000.
ERG. 2000b. Facility Counts for Beef, Dairy, Veal, and Heifer Operations. Memorandum from
Eastern Research Group, Inc. to the Feedlots Rulemaking Record. December 15,2000.
USDA ERS. 1997. Financial Performance of 'U.S. Commercial Farms, 1991-94. U.S.
Department of Agriculture Economic Research Service. AER-751. June 1997.
USDA APHIS. 1999. Re-aggregated Data from the National Animal Health Monitoring
System's (NAHMS) Swine '95 Study. Aggregated by Eric Bush of the U.S. Department of
3-9
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Agriculture, Animal and Plant Health Inspection System, Centers for Epidemiology and Animal
Health.
3-10
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CHAPTER 4
INDUSTRY PROFILES
4.0 INTRODUCTION
This chapter describes the current organization, production processes, and facility and waste
management.practices of the Animal Feeding Operations (AFO) and Concentrated Animal
Feeding Operations (CAFO) industries. Farm production methods, operation sizes, geographical
distributions, pollution reduction activities, and waste treatment practices in use are described
separately for the swine, poultry, beef, and dairy subcategories. Discussions of changes and
trends over the past several decades are also provided.
Information on animal production was generally obtained from USDA's 1997 Census of
Agriculture, USDA's National Agricultural Statistics Service (NASS), and information gathered
from site visits and trade associations. For information obtained from the 1997 Census of
Agriculture, EPA divided the U.S. into five production regions and designated them the South,
Mid-Atlantic, Midwest, West, and Central regions. Originally, the USDA Economic Research
Service (ERS) established ten regions so that it could group economic information. EPA
condensed these regions into the five AFO regions because of similarities hi animal production
and manure handling techniques, and to allow for the aggregation of critical data on the number
of facilities, production quantities, and financial conditions, which may otherwise not be possible
due to concerns about disclosure.' The production regions are defined in Table 4-1.
For example, USDA Census of Agriculture data are typically not released unless there is a sufficient
number of observations to ensure confidentially. Consequently, if data were aggregated on a state basis (instead of
a regional basis), many key data points needed to describe the industry segments would be unavailable.
4-1
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Table 4-1. Animal Feeding Operation (AFQ) Production Regions
Region
Central
Midwest
Mid-Atlantic
Pacific
South
States Included
Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Oklahoma, Texas, Utah,
Wyoming
Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota,
Ohio, South Dakota, Wisconsin
Connecticut, Delaware, Kentucky, Maine, Maryland, Massachusetts, New Hampshire, New
Jersey, New York, North Carolina, Pennsylvania, Rhode Island, Tennessee, Vermont,
Virginia, West Virginia
Alaska, California, Hawaii, Oregon, Washington
Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, South Carolina
4.1 Swine Industry Description
Swine feeding operations include facilities that confine swine for feeding or maintenance for at
least 45 days in any 12-month period. These facilities do not have significant vegetation in the
confinement area, during the normal growing season, thus swine pasture operations are generally
not included. Facilities that have swine feeding operations may also include other animal and
agricultural operations such as crop farming.
This section discusses the following aspects of the swine industry:
• 4.1.1: Distribution of the swine industry by size and region
• 4.1.2: Production cycles of swine
• 4.1.3: Swine facility types and management
• 4.1.4: Swine waste management practices
• 4.1.5: Pollution reduction ;
• 4.1.6: Waste disposal
The swine industry is a significant component fof the domestic agricultural sector, generating
farm receipts ranging from $9.2 billion to more than $11.5 billion annually during the past
decade (USDA NASS, 1998a). Total annual receipts from the sale of hogs average
approximately 12 percent of all livestock sales and 5 percent of all farm commodity sales.
Annual swine output ranks fourth in livestock production value, after cattle, dairy products, and
broilers. During 1997, more than 17 billion pounds of pork were processed from 93 million
hogs. The retail value of pork sold to consumers exceeded $30 billion. The National Pork
Producers Council estimates that the pork industry supports more than 600,000 jobs nationally
(NPPC, 1999).
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As described in the following sections, the swine industry has undergone a major transformation
during the past several decades. Swine production has shifted from small, geographically
dispersed family operations to large "factory farms" concentrated primarily in 10 states in the
Midwest and the South. The number of hog operations, which approached 3 million in the
1950s, had declined to about 110,000 by 1997. The rate of consolidation has increased
dramatically in the last decade, which has seen more than a 50 percent decline in the number of
swine operations (USDA NASS, 1999a). All indications are that this trend toward consolidation
is continuing.
Swine production has also changed dramatically in terms of the production process and the type
of animal produced. The hog raised for today's consumer is markedly different from the one
produced in the 1950s: Today hogs contain approximately 50 percent less fat and are the result of
superior genetics and more efficient diets. The average whole-herd feed conversion ratio
(pounds of feed per pound of live weight produced) used to be between 4 and 5 and has steadily
decreased with current averages between 3.6 and 3.8. The most efficient herds have whole-herd
feed conversion ratios under 3.0 (NPPC, 1999). Hence, a well-run swine operation can currently
produce a 250-pound hog using only 750'pounds of animal feed during its lifetime.
The domestic hog industry is increasingly dominated by large, indoor, totally confined operations
capable of handling 5,000 hogs or more at a time (USDA NASS, 1999b, and USDA NASS,
1999c). These pperations typically produce no other livestock or crop commodities. In addition,
there has been greater specialization as more swine operations serve only as nursery or finishing
operations.
Another growing trend in the industry is that more hogs are being produced under contract
arrangement whereby large hog producers, typically referred to as integrators or contractors,
establish production contracts with smaller growers to feed hogs to market weight. The producer-
integrator provides management services, feeder pigs, food, medicine, and other inputs, while the
grower operations provide the labor and facilities. In return, each grower receives a fixed
payment, adjusted for production efficiency. These arrangements allow integrators-to grow
rapidly by leveraging their capital. For example, instead of investing in all the buildings and
equipment required for a farrow-to-finish operation, the integrator can invest in specialized
facilities, such as farrowing units, while the growers pay for the remaining facilities, such as the
nurseries and finishing facilities (Martinez, 1999). Occasionally other forms of contracts maybe
used.
According to a survey conducted for the USDA, 11 percent of the nation's hog inventory at the
end of 1993 was produced under long-term contracts. This percentage was expected to increase
to 29 percent by 1998 (Martinez, 1997). Regionally, the Mid-Atlantic region has the greatest
proportion of contracted hogs, with more than 65 percent of the hogs grown at facilities where
the grower does not own the hogs (USDA NASS 1999c).
These changes at both the industry and farm levels represent a significant departure from earlier
eras, when hogs were produced primarily on relatively small but integrated farms where crop
4-3
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production and other livestock production activities occurred and where animals spent their
complete life cycle. The following sections describe the current production and management
practices of domestic swine producers. ,
4.1.1 Distribution of Swine Operations by Size and Region
EPA's 1974 CAFO Effluent Limitations Guidelines and Standards generally apply to swine
feeding operations with more than 2,500 head, but counts only those swine weighing more than.
55 pounds. (See Chapter 2 for the definition of a CAFO, and Chapter 5 for a discussion of the
basis for revisions to the swine subcategory.) Most data sources cited in this section do not
distinguish swine by weight, but may provide other information that distinguishes sows and other
breeding pigs, feeder pigs, litters, and market pigs. Where numbers of head are presented in the
following sections, feeder pigs were not included in the counts unless specified in the text.
4.1.1.1 National Overview
The estimated number of domestic.swine operations has continuously declined since the 1950s.
As recently as 1970, there were more than 870,000 producers of swine. By 1997, this number
had decreased to about 110,000 (USDA NASSj 1999b).2 The decline has been especially
dramatic over the past decade. As shown in Table 4-2, the number of operations has steadily
decreased over the years.
Table 4-2. Changes in the Number of U.S. Swine Operations and Inventory 1982-1997
Year
1982
1987
1992
1997
Operations
329,833
243,398
191,347
109.754
Inventory
55,366,205
52,271,120
57,563,118
61,206:236
Source: USDA NASS, 1999b
As the number of operations has decreased, however, hog inventories have actually risen due to
the emerging market dominance by larger operations. Inventories increased from 55.4 million
head in 1982 to 61.2 million head in 1997 (USDA NASS, 1999b).
4.1.1.2 Operations by Size Class
The general trend in the U.S. swine industry is toward a smaller number of large operations
(Table 4-3). As the percentage of smaller producers decreases, there is a consistent increase in
the percentage of herds with a total inventory of 2,000 or more head. The increase in the number
" USDA defines an operation as any place having one or more hogs or pigs on hand at any time during the
year.
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of large operations has predominantly occurred in conjunction with extended use of total
confinement operations, which separate the three production phases described in 4.1.2.
Table 4-3. Percentage of U.S. Hog Operations and Inventory by Herd Size
Year
1982
1987
1992 ,
1997
I 0-1,999 Head
Operations
99.3
98.9
97.9
94.4
Inventory
85.7
79.0
68.7
39.3
2,000-4,999 Head
Operations
0.6
1.0
1.6
3.9
9.5
129
15.2
20.8
More Than 5.000 Head
Operations
0.1
0.2
0.4
1.7
4.8
8.1
17.0
40.2
In terms of farm numbers, small operations still dominate the industry; however, their
contribution to total annual hog production has decreased dramatically in the past decade. For
example, operations with up to 1,999 head, which produced 85.7 percent of the nation's hogs in
1982, raised only 39.3 percent of the total in 1997. fci contrast, in 1982, the 0.1 percent of
operations that reported more than 5,000 head produced approximately 5 percent of the swine; in
1997 these large operations (1.7 percent of all operations) produced over 40 percent of the
nation's hogs.
4.1.1.3 Regional Variation in Hog Operations
Swine farming historically has been centered in the Midwest region of the U.S., with Iowa being
the largest hog producer in the country. Although the Midwest continues to be the nation's
leading hog producer (five of the top seven producers are still in the Midwest), significant growth
has taken place in other areas. (See Table 4-4.) Perhaps the most dramatic growth has occurred
in the Mid-Atlantic Region, in North Carolina. From 1987 to 1997, North Carolina advanced
from being the 12th largest pork producer in the nation to second behind only Iowa. Climate and
favorable regulatory policies played a major role in the growth of North Carolina's swine
industry.
North Carolina's winters are mild and summers are tolerable, and this has allowed growers to use
open-sided buildings. Such buildings are less expensive than the solid-sided buildings made
necessary by the Midwest's cold winters. Midwestern growers must also insulate or heat then-
buildings in the winter. Tobacco farmers, who found hogs a means of diversifying then-
operations, also fueled North Carolina's pork boom. The idea of locating production phases at
different sites was developed hi North Carolina. The state also has a much higher average
inventory per farm than any of the states in the Corn Belt. Whereas Iowa had an average of
fewer than 850 head per farm, North Carolina had an average of more than 3,200 head per farm
in 1997. In recent years, significant growth has occurred elsewhere as well: in the Central
Region in the panhandle area of Texas and Oklahoma, Colorado, Utah, and Wyoming as well as
in the Midwest Region in northern Iowa and southern Minnesota.
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Tables 4-4 through 4-7 present the distribution; of different types of swine operations for the key
producing regions. For the purposes of these tables, breeder operations, also known as farrowing
operations, have large numbers of sows and sell or transfer the pigs when they have been weaned
or grown to approximately 55 pounds (feeder pigs); some farrowing operations may also keep
boars. Nursery operations receive weaned pigs and grow them to approximately 55 pounds.
Grow-finish operations are operations that receive feeder pigs and grow them out to marketable
weight; these pigs are often labeled "swine for ^slaughter." Combined operations perform all
phases of production, known in the industry as "farrow-to finish," or just the final two phases
such as "wean-finish." Note that no large independent nurseries are depicted by the 1997 census
data. EPA is aware that several large nurseries have recently begun operation or are under
construction. The considerable amount of growth in the Central (Southwest) Region that has
occurred in the past 3 years is not reflected in the 1997 statistics presented in this section.
Table 4-4 shows the number of operations for six different size classes of facilities. Table 4-5
presents the average herd size by operation type, region, and operation size. Table 4-6 presents
the percentage of total swine animal counts at combined and slaughter operations by region and
operation size. Table 4-7 presents the distribution of different animal types in combined swine
operations by region and operation size.
Table 4-4. Total Number of Swine Operations by Region, Operation Type, and Size in 1997
Region1
Mid
Atlantic
Midwest
Other
National
Operation
Type"
combined
slaughter
combined
slaughter
combined
slaughter
combined
slaughter
breeder
nursery
Number of Swine Operations (Operation Size Presented by Number of Head)
XK750
6,498
8,12.0
35,263
27,081
10,821
13,502
52,582
48,703
2,227
>750-
1,875
421
344
5,212
2,194
359
83
5,992
2,621
>1,875-
,2,500
1 82
150
782
425
74
! 50
938
625
15
>2,500-
5,000
185
413
1,106
521
135
91
1,426
1,025
>5,000-
10,000
130
281
410
142
60
45
' 600
468
>10,000
: 135
119
213
48
45
1.0
393
- 177
3
83
0
Total
7,451
9,427
42,986
30,411
11,494
13,781
61,931
53,619
2,245
83
•Mid Atlantic= ME, NH, VT, NY, MA, W, CT, NJ, PA, DE, MD, VA, WV, KY, TN, NC; Midwest= ND, SD, MM, MI, WI, OH, IN, IL, IA,
MO, NE, KS; Other= ID, MT, WY, NV;UT, CO, AZ, NM, TX, OK, WA, OR, WA, OR, CA, AK, HI, AR, LA, MS, AL, GA, SC, EL
* Operation type: combined=breeding inventory, finishing (average of inventory and sold/2.8), and feeders (sold/10);
slaughter=finishing (average of inventory and sold/2.8); breeding (inventory); and nursery (feeders sold/10).
4-6
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Table 4-5. Average Number of Swine at Various Operations by Region Operation Type,
and Size in 1997
Region"
Mid-
Atlantic
Midwest
Other
National
Operation
Type"
combined
slaughter
combined
slaughter
combined
slaughter
combined
slaughter
Average Swine Animal Counts (Operation Size Presented by Number of Head)
>0-750
74
'32
209
135
51
13
160
84
>750-
1,875
1,182
1,242
1,137
1,161
1,255
1,291
1,147
1,176
>1,875-
2,500
2,165
2,184
2,152
2,124
2,150
2,215
2,153
2,146
>2,500-
5,000
3,509
3,554
3,444
3,417
3,455
3,626
3,453
3,491
>5,000-
10,000
5,021
6,877
6,761
6,791
7,052
6,830
6,413
6,846
>10,000
28,766
13,653
27,403
19,607
59,172
14,901
31,509
15,338
All
Operations
851
641
637
355
410
85
621
336
•CentraWD, MT, WY,'NV, UT, CO, AZ, NM, IX, OK; MidwesMND, SD, MN, MI, WI, OH, IN, IL, IA, MO, NE, KS; Other=ME NH
VT,>ry,MA,RI>CT,NJ,PA,DE,MD,VA>WV,KY,TN,NC,WA,OR,CA>AK,HtAR,LA,MS,AL,GA,SC,FL ' '
Operation type: combined=breeding inventory, finishing (average of inventory and sold/2.8), and feeders (sold/10);
slaughtei=finishing (average of inventory and sold/2.8).
Source: USDANASS, 1999c
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Table 4-6. Distribution of Swine Herd by Region, Operation Type, and Size in 1997
Region*
Mid
Atlantic
Midwest
Other
National
Operation
Type"
combined
slaughter
combined
slaughter
combined
slaughter
combined
slaughter
Percentage of Total Swine Animal Counts by Size Group
(Operation Size Presented by Number of Head)
XK750
1.25
1.45
19.14
20.26
1.44
0.94
21.83
22.65
>750-
1,875
1.30
2.37
15.42
14.16
1.17
0.60
17.88
17.13
>1,875-
2,500
0.46
1.82
4.38
5.02
, 0.41
0.62
5.25
7.45
>2,500-
5,000
1.69
8.16
9.91
9.89
1.21
1.83
12.81
19.88
>5,000-
10,000
1.70
10.74
7.21
5.36.
1.10
1.71
10.01
17.80
>10,000
10.10
9.03
15.18
5.23
6.93
0.83
32.21
15.09
Total
16.50
33.56
71.24
59.92
12.26
6.52
100.00
100.00
•CentraMD, MT, WY, NV, UT, CO, AZ, MM, XX, OK; Midwest=ND, SD, MM, MI, WI, OH, IN, IL, IA, MO, ME, KS; Other=ME, NH,
VT, NY, MA, 10, CT, NJ, PA, DE, MD, VA, WV, KY, TO, NC, WA, OR, CA, AK, HI, AR, LA, MS, AL, GA, SC, FL
b Operation type: combined=breeding inventory, finishing (average of inventory and sold/2i8), and feeders (sold/10);
slaughter=finishing (average of inventory and sold/2.8).
Source! USDANASS,1999c
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Table 4-7. Distribution of Animal Type in Swine Herds at
Combined Facilities by Region, Operation Type, and Size in 1997
Region "
Mid
Atlantic
Midwest
Other
National
Swine Type"
Breeding '
Finishing
Feeder
Breeding
Finishing
Feeder
Breeding
Finishing
Feeder
Breeding
Finishing
Feeder!
Percentage of Breeding, Finishing, and Feeder Hogs at Combined Facilities
(Operation Size Presented by Number of Head)
>0-750
19.84
73.96
6.20
17.85
78.33
3.82
22.47
73.03
4.48
18.27
77.73
4.00
>750-
1,875
17.38
71.74
10.88
16.14
79.59
4.26
19.95
61.02
19.04
16.50
77.70
5.79
>1,875-
2,500
15.59
72.46
11.95
16.55
76.66
6.80
19.54
69.00
11.46
16.70
75.66
7.63
>2,500-
5,000
17.68
65.56
16.75
15.88
76.38
7.73
18.38
71.39
10.23
16.36
74.44
9.21
>5,000-
10,000
16.66
59.02
24.32
15.23
77.77
7.00
20.84
64.45
14.71 .
16.16
71.78
12.05
>10,000
17.19
58.55
24.25
14.65
80.32
5.03
17.54
78.57
3.90
16.10
72.63
11.27
All
Operations
17.31
61.61
. 21.08
16.18
78.59
" 5.23
18.74
. 73.89
7.37
16.66
74.91
8.40
•CentraHTO, MT, WY, NV, UT, CO, AZ, MM, IX, OK; Midwest?=ND, SD, MN, MS, WJ, OH, IN, JL, IA, MO, ME, KS; Other=ME NH
VT, NY, MA, W, CT, NJ, PA, DE, MD, VA, W, KY, IN, NC, WA, OR, CA, AK, HI, AR, LA, MS, AL, QA,,SC,FL
Swine type: Breeding = inventory; finishing = average of inventory and sold/2.8- and feeder= sold/10
Source: USDANASS, 1999c
4.1.2 Production Cycles of Swine
Swine production falls into three phases. Pigs are farrowed, or born, in farrowing operations.
Sows are usually tired for the first time when they are 180 to 200 days old. Farrowing facilities
range from pasture systems to completely confined housing systems. A sow's gestation period is
about 114 days. Farrowings are typically 9 to 11 pigs per Utter, with a practical range of 6 to 13.
The highest death losses in the pig-raising cycle occur within 3 to 4 days of birth. 'The average
, number of pigs weaned per litter in 1997 was 8.67. See Table 4-8. Producers incur significant
expenses in keeping a sow, so the survival of each pig is critical to overall profitability. Sows
usually resume sexual activity within a week after a litter is weaned. Growers are able to roughly
synchronize production by weaning all their baby pigs on the same day. When they do this, all
the sows in a farrowing group become sexually active again at roughly the same tune and may be
bred again at the same tune. The sows will then farrow at about the same time, over a period of
about a week. In this way, growers are able to keep groups of pigs together as they move from
4-9
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one phase of production to another. Sows normally produce five to six litters before they are
culled and sold for slaughter at a weight of 400 to 460 pounds.
Table 4-8. Productivity Measures of Pigs
Year
1992
1993
1994
1995
1996
1997
Average
Number of Pigs
Weaned per Litter
8.08
8.13
8.19
8.32
8.50
8.67
8.32
Per Breeding Animal per Year
Litters
1.69
1.68
1.73
1.68
1.64
1.72
1.69
Head to Slaughter
13.08
13.06
13.36
13.64
13.51
13.79
'13.41
Average Live
Weight per Pig
(pounds)
252
254
255
256
257
260
256
Source: NPPC, 1999
Baby pigs are typically allowed to nurse from the sow, and then are relocated to a nursery, the
second phase of swine production. In the nursery phase, pigs are weaned at 3-4 weeks of age and
weigh 10 to 15 pounds. In the nursery, the pigs are raised to 8 to 10 weeks of age and 40 to 60
pounds. In practice, the weaning phase may take as few as 10 days, and may exceed 35 days.
During the third phase of production, growing pigs are raised to a market weight of 240 to 280
pounds. Finishing takes another 15 to 18 weeks, thus hogs are typically sent to market when they
are about 26 weeks old (see Table 4-9). The growing and finishing phases were once separate
production units, but are now combined in a single unit called grow-finish. In the
growiag-finishing unit, pigs are raised from 50 or 60 pounds to final market weight. The
average grow-finish facility will produce approximately 2>8 turns (also called life cycles, herds,
or groups) annually. Typically, finished pigs are from 166 to 212 days old, resulting hi a range of
2.4 to 3.4 turns (or groups) of pigs produced from the grow-finish unit per year. Average farrow-
to-finish operations will produce 2.1 groups per sow per year. The range of annual turnover
frequency at farrow-to-finish farms is from 1.8 to 2.5.
;4-10
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Table 4-9. Age of Pigs Leaving Grow-Finish Unit in 1995
Age of Pig on Leaving Grow-
Finish Unit (days)
120-159
160-165
166-180
181-209
210 or more
Weighted Average
Percentage of Operations and Pigs
Percentage of Operations
12.5
16.7
49.6
16.3
4.9
173 days
Percentage of Pigs
12.2
12.6
45.8
24.9
4.5
175 days
Source: USDA APHIS, 1995
In 1995, most operations had a farrowing facility, whereas slightly less than half of the facilities
nationwide had a separate nursery facility. Most operations (85.6 percent) did have a finishing
facility. Finishing operations get their pigs from on-site farrowing and nursery units (76.7
percent), off-site! farrowing operations (10.2 percent), feeder pig producers under both contract
and noncontract arrangements (13.8 percent), or livestock auctions or sales (5.9 percent). Large
finishing operations (>10,000 head marketed) were more likely (56.3 percent) to get their pigs
from off-site sources (USDA APHIS, 1995). Tables 4-10 and 4-11 present the frequency of the
three major production phases by region and size. The sample profile of the Swine '95 survey
indicates that 61:9 percent of respondents were farrow-to-finish operations and that 24.3 percent
were grow-finishoperations.
Table 4-10. Frequency of Production Phases in 1995 on Operations That
Marketed Less Than 5,000 Hogs in a 6-Month Period
Production Phase
Farrowing
Nursery
Finishing
USDA APHIS Region"
Midwest
76.6
20.1
78.8
North
68.6
51
79.7
Southeast
69.3
57.8
93.4
* Midwest=SD, NE, MM, IA, EL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA; Only the 16 major pork states that accounted
for nearly 91 percent of tJ.S. hog inventory were surveyed.
Source: USDA APHIS, 1995
4-11 .
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Table 4-11. Frequency of Production Phases in 1995 on Operations That
Marketed 5,000 or More Hogs in a 6-Month Period
Production Phase
Farrowing
Nursery
Finishing
USDA APHIS Region2
Midwest
44.8 ;
75
45.8
North
80.4
67.1
69.7
Southeast
89
97.4
62.8
• Midwest-SD, NE, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, OA; Only the 16 major pork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA APHIS, 1995 .
Although many large operations continue to have the full range of production phases at one
facility, these operations are no longer the norm. More frequently, in new operations, several
specialized farms are linked, or horizontally integrated, into a chain of production and marketing.
Pigs begin in sowherds on one site, move to a nursery on another, and then move again to a
finishing facility. Specialized operations can take advantage of skilled labor, expertise, advanced
technology, streamlined management, and modern housing. However, the primary advantage of
specialization is disease control. In a farrow-to-finish operation, a disease outbreak that begins in
one phase of the operation can spread to the other phases. Physically separating the phases
makes it easier to break this disease cycle. At the same time, separating phases spreads the cost
of establishing swine operations, particularly if the different operations are owned by different
persons.
Thus other categories of swine operations may comprise two or three of the three phrases
described: combined farrow-nursery operations, which breed pigs and sell them at 40 to 60
pounds to finishing operations; wean-to-finish operations, which finish weaned pigs; and fairrow-
to-finish operations, which handle all phases of production from breeding through finishing. The
emerging trend in the mid to late '90s was to produce pigs in two production phases rather than
in three. In two-phase production, the weaned pigs may go straight into the grower building or
finishing building, bypassing the nursery. The advantages of such practices are reduced
transportation costs, lessened animal stress, and reduced animal mortality.
4.1.3 Swine Facility Types and Management
Table 4-12 summarizes the five major housing configurations used by domestic swine producers.
Although there are still many operations at which pigs are raised outdoors, the trend in the swine
industry is toward larger confinement facilities where pigs are raised indoors. A typical'
confinement farrowing operation houses 3,000 sows, although some farrowing operations house
as many as 10,000 sows at one location, and farms are being planned that will house as many as
4-12
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15,000 sows at one location. Typical nursery operations are much smaller with a capacity of only
about 1,500 head, but as stated earlier, separate nursery facilities are relatively uncommon.
Table 4-12. Summary of Major Swine Housing Facilities
Facility Type"
Total confinement
Open building with no outside
access
Open building with outside access
Lot with hut or no building
Pasture with hut or no building
Description
Pigs are raised in pens or stalls in
an environmentally controlled
building.
Pigs are raised in pens or stalls but
are exposed to natural climate •
conditions.
Pigs are raised in pens or stalls but
may be moved to outdoors.
Pigs are raised on cement or soil lot
and are not confined to pens or
stalls.
Pigs are raised on natural pasture
land and are not confined to pens
or stalls.
Applicability
Most commonly used in nursery
and farrowing operations and all
phases of very large operations.
Particularly common in the
Southeast.
Relatively uncommon but used by
operations of all sizes.
Relatively uncommon, but used by
some small, to mid-sized operations.
Used by small to mid-sized
operations.
Traditional method of raising hogs
currently used only at small
operations.
" These are the main facility configurations contained in the Swine '95 Survey conducted by USDA APHIS, 1995.
The economic advantages of confined facilities have been the primary driving factor (especially
at large operations) for farmers to abandon dry lot or pasture raising of hogs. Although
controlled-environment buildings require a greater initial capital investment than traditional farm
operations, labor costs per unit output are significantly reduced. Furthermore, these facilities
allow for far greater control of the production process, protect both animals and workers from
weather, and usually result in faster growth-to-market weight and better feed efficiency. Most
: controlled-environment facilities employ "all in, all out" production, hi which pigs are moved in
groups and buildings are cleaned and disinfected between groups. It should be noted that the
success of a controlled-environment operation is highly dependent on properly functioning
ventilation, heating and cooling, and waste removal systems. A prolonged breakdown of any of
these systems during extreme weather conditions can be catastrophic to the pig herd and
economically devastating to the operator.
Facility requirements differ somewhat for each phase in a hog's life cycle, and hence farrowing,
nursery, and growrng/finishing facilities are configured differently. For example, farrowing
operations require more intense management to ensure optimal production and reduce piglet
mortality. A typical farrowing pen measures 5 by 7 feet, and the litter is provided with a
protected area of approximately 8 square feet. The sow is relegated to a section of the pen and is
separated from the piglets by low guard rails that reduce crushing but do not interfere with
4-13
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suckling. Floors are usually slatted under or tq the rear of the sow area to facilitate waste
removal (NPPC, 1996).
Newly born piglets require special care because of their vulnerability to injury and disease.
Nursery systems are typically designed to provide a warm, dry, and draft-free environment in
which animal stress is minimized to promote rapid growth and reduce injury and mortality.
Nursery rooms are regularly cleaned and sanitized to reduce the piglets' exposure to pathogens.
Nursery buildings are cleaned and disinfected thoroughly between groups of pigs to prevent the
transmission of disease from one herd to another. Nursery pens usually hold 10 to 20 pigs. Pigs
are held in the nursery from weaning until they are 8 to 12 weeks old (NPPC, 1996).
Finishing pigs at finishing facilities tend to require less intensive management than piglets and
can tolerate greater variations in environmental conditions without incurring health problems. In
an environmentally controlled building, growing and finishing pens hold 15 to 40 pigs and allow
about 6 square feet per pig. Overcrowding leads to stress and aggressive behavior and can result
in reduced growth rates and injury. Slatted concrete floors are the most common (NPPC, 1996).
As shown in Tables 4-13 through 4-18, smaller facilities tend to use open buildings, with or
without access to the outside. Usually, hogs raised in these building are also confined to pens or
stalls. Depending on the climate, the building might require ventilation and mist sprayer systems
to prevent heat stress in the summer. Bedding might be needed during the winter months to
protect the animals from the cold. :
F
Hogs raised on dry lots or pasture require care and management similar to that for animals raised
indoors, plus additional measures to protect the herds from extreme weather conditions. They
must be provided with sufficient shade to reduce heat stress in the summer. Where natural shade
is not available, facilities can be constructed to protect the herd from the sun in the summer and
from wind and cold during the winter. Windbreaks are used under certain environmental
conditions. ;
The most comprehensive information on swine facility and waste management systems currently
in use by farm type, size, and state location wa? collected in conjunction with USDA's Swine '95
study (USDA APHIS, 1995). Included in the Istudy were 16 major pork-producing states that
accounted for almost 91 percent of the U.S. hog inventory and more than 70 percent of the pork
producers. The samples for the major swine-raising operations were statistically designed to
provide inferences to the nation's swine population. Although the survey was conducted by the
Animal and Plant Health Inspection Service (APHIS) and focused on swine health issues, it
contains much information on swine production and on facility and waste management. Tables
4-13 and 4-14 present information on the housing types used in the farrowing phase. Tables 4-15
and 4-16 present information on the housing types used in the nursery phase. Tables 4-17 and 4-
18 present information on the housing types used in the finisher phase. These tables clearly
demonstrate that the larger facilities tend to use total confinement in all regions.
4-14
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Table 4-13. Housing Frequency (in percent) in 1995 of Farrowing Facilities at Operations
That Marketed Fewer Than 5,00ft Hogs in a 6-Month Period
Variable
Total Confinement
Open Building; no
outside access
Open Building; outside
access
Lot
Pasture
USDAAPfflS Region"
Midwest
22.6
13.1
25.7
16.2
22.4
North
53.1
8.0
33.8
3.2
1.9
Southeast
56
8.8
31.2
1.1
2.8
• Midwest=SD, ME, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TO, NC, GA; Only the 16 major pork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA APHIS, 1995 ' :
Table 4-14. Housing Frequency (in percent) in 1995 of Farrowing Facilities at Operations
That Marketed 5,000 or More Hogs in a 6-Month Period
Variable
Total Confinement.
USDA APHIS Region8
Midwest
98.3
North
100
Southeast
100
" Midwest=SD, NE, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA; Only the 16 major pork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA APHIS, 1995
4-15
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Table 4-15. Housing Frequency (in percent) in 1995 of Nursery Facilities at Operations
That Marketed Fewer Than 5,000 Hogs in a 6-Month Period
Variable
Total Confinement
Open Building; no
outside access
Open Building; outside
access
Lot
USDAAPfflS Region"
Midwest
52.3
9.1
27.7 '
7.0
North
55.4
, 11.5
33.8
not available
Southeast
62
8.8
31.2
3.7
• Midwest=SD, ME, MN, IA, IL; North=WL MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA; Only the 16 major pork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDAAPfflS, 1995
Table 4-16. Housing Frequency (in percent) in 1995 of Nursery Facilities at Operations
That Marketed 5,000 or More Hogs in a 6-Month Period
Variable
Total Confinement
USDA APHIS Region"
Midwest •
99
North
100
Southeast
96.4
1 Midwest=SD, ME, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA; Only the 16 major pork states that accounted
lot-nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA APHIS, 1995
Table 4-17. Housing Frequency (in percent) in 1995 of Finishing Facilities at Operations
Variable
Total Confinement
Open Building; no
outside access
Open Building; outside
access
Lot
Pasture
Midwest
19.9
15.4
24.5
i
17.1
23.0
USDA APHIS Region-
North
36.5
14.1
42.1
4.6
2.5
Southeast
23.4
9.5
55.9
9.3
1-9
" Midwest=SD, NE, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA; Only the 16 major pork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA APHIS, 1995
4-16
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Table 4-18. Housing Frequency (in percent) in 1995 of Finishing Facilities at Operations
i That Marketed 5,000 or More Hogs in a 6-Month Period
Variable
Total Confinement
Region"
Midwest
96.8
North
95.5
Southeast
83.9
' ' ''—3—' •» ~ •—9 **•» v*-*j **»> w**m**i0L AW-VS AVA, Hi, n^, \jn, \-*iiiy uic 10 uiajurporKstares mat accounieu
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA APHIS, 1995
4.1.4 Swine Waste Management Practices
Removal of manure from the animals' living space is critical for animal and farm worker well-
being. Odor, gases, and dust carried by ventilation exhaust air are also affected by the waste
management system used. Swine waste management systems can be separated into collection,
storage, and treatment practices. An overview of the major practices in each of these areas is
presented below; more detailed information on waste collection, storage, and treatment practices
is provided in Section 8 of this document. Although the practices described below do not
represent all of the waste management practices in use today, they are the predominant practices
currently used at swine operations.
Swine Waste Collection Practices
Indoor raising of hogs requires that animals be physically separated from their waste products.
Separation in larger facilities is usually accomplished through the use of concrete flooring with
slots that allow the waste to drop below the living area and be transferred to a pit or trough
beneath the pen. Smaller facilities hand clean pens to collect wastes.
The most frequently reported waste management system used in 1990 was hand cleaning (41.6
percent), which declined in use to 28.3 percent of operations in 1995 (USDA APHIS, 1995).
This decrease in hand cleaning is highly correlated to the decrease in smaller facilities. Some
facilities separate solid material from liquids before moving the material to storage. (A
discussion of solid-liquid separation is presented in Section 8.) Slatted floors are now more
commonly used to separate the manure from the animals at larger facilities. The waste is then
deposited in an under floor pit or gutter where it is stored or moved to another type of storage.
There are two main types of under-floor collection practices in which the waste is moved for
storage elsewhere.
• Pit recharge. Pit recharge is the periodic draining of the pit contents by gravity to storage,
followed by recharging the pit with new or recycled water. Regular pit draining removes
much of the manure solids that would otherwise settle and remain in the bottom of the pit.
The regular dissolution of settled solids increases the likelihood the solids will be removed at
the next pit draining. Recharge systems use a 16- to 18-inch-deep in-house pit with 6 to 8
4-17
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inches of water, which is emptied every 7 days to an anaerobic lagoon. Previously, 24-inch-
deep pits were preferred, but now shallower pits are used with the hog slat system.
!
[
• Flush. Flush systems may use fresh water lor recycled lagoon water for frequent removal of
feces and urine from under-floor collection gutters or shallow pits. Like pit recharge systems,
flush systems also improve animal health and performance as well as human working
conditions in the swine houses by avoiding prolonged storage. Flush tanks with the capacity
to release at least 1.5 gallons per 10Q pounds of live animal weight per flush are placed at the
end of the swine houses. Pit floors should be level from side to side, and wide pits should be
divided into individual channels no wider than 4 to 5 feet. The floor slope for most flush
systems is between 1 and 2 percent. Floors are flushed at least 1 to 12 times per day; the
flush tanks are filled with new or recycled lagoon water before every flush. The flushed waste
is collected and removed from the houses into storage through a system similar to that used in
pit recharge systems. .
Swine Waste Storage Practices
Waste storage is critical to the proper management of wastes from animal feeding operations
because manure nutrients are best applied to farmland only at certain times of the year, as
determined by crops, climate, and weather. Storage practices include deep pits, anaerobic .and
aerobic lagoons, aboveground and belowground slurry storage (tanks or pits), and dry storage.
Most large hog farms (more than 80 percent) nave from 90 to 365 days of waste storage capacity.
(See Table 4-19.) ;
Table 4-19. Percentage of Swine Facilities With Manure Storage in 1998
Annual
Marketed Head
NA
0-1,000
1,000-2,000
2,000-3,000
3,000-5,000
5,000-10,000
10,000-20,000
20,000-50,000
50,000 +
0-3 months
3.2
31.9
14.9
10.1
5.8
6.1
4.7
6.0
4.0
3-6 months
3.7
27.2
38.0
35.4
33.5
29.2
26.4
23.5
19.5
6-9 months
3.2
12.3
20.7
21.9
22.8
22..1
21.1
22.8
28.7
9-12 months
7.4
17.4
19.4
28.1
32.6
35.6
. 40.9
39.2
28.0
None or NA
82.5
11.3
7.1
4.4
5.3
7.0
6.8
8.6
19.8
Source: NPPC, 1998
An overview of common waste storage practices is provided below; More detailed information
can be found in Section 8 of this document.
;4-18
-------
Deep pit manure storage. Many operations use pits that are 6- to 8- feet deep and provide
for up to 6 months' storage under the house. Commonly, slurry is removed from the pit twice
a year. The slurry is disposed of through direct surface application or subsurface injection,
transferred to an earthen storage facility, or pumped to an aboveground or belowground
storage tank. This slurry system produces a waste stream with higher dry matter content (4 to
5 percent) and higher nutrient content than other liquid manure systems. The aboveground
and belowground storage systems conserve more nitrogen than other systems (nitrogen loss
of only 10 to 30 percent). Operations use this system to avoid problems associated with
lagoons, such as odor, ammonia volatilization, and ground water impact resulting from
leaking lagoons.
Lagoon Systems. Lagoon systems can serve as both storage and treatment units. Anaerobic
lagoons are the most common type of lagoon and are characterized by anaerobic
decomposition of organic wastes. When properly designed an anaerobic lagoon will have a
minimum total capacity that includes appropriate design treatment capacity, additional
storage for sludge accumulation, and temporary storage for rainfall and wastewater inputs. A
lagoon should also have sufficient freeboard and an indicator of the highest safe water level,
to prevent the wastewater from overflowing the embankment.
Lagoons usually fill to capacity within 2 to 3 years of startup due to the accumulated waste
volume and, depending on the.region, rainfall in excess of evaporation. When the lagoon is '
full, water overflow will occur unless the operator is in a position to apply the excess water to
the land. Lagoon water drawdown by irrigation or other methods is usually begun before the
water reaches the maximum wastewater storage level. Several states require that liquid level
indicators be placed in the lagoon to be sure that the liquid stays below the level required to
contain the 24-hour, 25-year storm. •
In addition to anaerobic lagoons, there are aerobic lagoons (which mix and aerate waste via
mechanical aerators or ozone generators), two-stage lagoons (typically a constant volume
covered treatment cell followed by a storage cell), and multi-stage cell lagoons. Technical
information and a discussion of the advantages and disadvantages of these types of lagoons is
presented in Section 8 of this document.
Settling and evaporation ponds. Earthen ponds are used by some swine operations for solids
separation. These ponds are designed to remove 40 percent of the total solids (in a 6 percent
solids form) based on 3 months' storage. The material is then moved to another earthen pit,
which serves as a drying bed, or flow is diverted to a parallel solids removal pond. The slurry
dries to about 38 percent solids and 3-inch thickness within 6 months. The material is then
moved with a front-end loader into a box-type spreader and applied to the land. Solids drying
ponds and beds are not covered and therefore exposed to rainfall. A floating pump is located
half the lagoon distance from the inlet, with a screen over the intake to protect sprinkler
nozzles. The .supernatant is pumped and used to irrigate fields. Another variation is to use a
single lagoon followed by an evaporation pond that is 6 feet deep and as big as possible.
Some evaporation ponds dry up during the summer. Because of odor problems, there is a
4-19
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trend away from the earthen pond for solids separation to either a single anaerobic lagoon or
an anaerobic lagoon and an evaporation pond.
• Waste runoff storage. These systems described above can also be associated with operations
that maintain hogs on an outside lot for at least part of the time. Such operations might also
use housing similar to the systems described above, but allow outside access for the animals.
Dry lot areas may be paved or dirt, and manure is stored in piles that are created by tractor or
scraping system. Although controls might be in place to contain manure from enclosed areas
through use of a deep pit or lagoon, they are not generally protective of the outside
environment. Other typical runoff controls include surface diversions to prevent rainwater
from running onto the lot and/or a crude settling basin with a slotted overflow.
• Other. Other types of waste management practices currently used include above-and
belowground tanks (possibly covered and/or aerated), and hoop housing/deep bedding
systems.
Swine Waste Treatment Practices
Many types of technology areiised to treat swjne wastes. These technologies work in a variety of
ways to reduce the nitrogen, chemical oxygen, demand, and the volatile solids content of waste or
to change the form of the waste to make it more concentrated and thus easier to handle. The
most common type of treatment practice is the anaerobic lagoon.
• Lagoon treatment systems. Lagoons designed to treat waste can reduce organic content and
nitrogen by more than 50 percent (PADER, 1986). Anaerobic lagoons are generally
preferred over aerobic lagoons because of their greater ability to handle high organic load.
Nonetheless, incomplete anaerobic decomposition of organic material can result in offensive
by-products, primarily hydrogen sulfide, ammonia, and intermediate organic acids, which can
cause disagreeable odors. Therefore, proper design, size, and management are necessary to
operate an anaerobic lagoon successfully.
New lagoons are typically half filled with water before waste loading begins. Starting up
during warm weather and seeding with bottom sludge from a working lagoon speeds
establishment of a stable bacterial population. Proper lagoon maintenance and operation is
absolutely necessary to ensure that lagoon liner integrity is not affected, that berms and
embankments are stable, and the required freeboard and rainfall storage are provided.
Even when bacterial digestion is efficient significant amounts of sludge accumulate in
anaerobic lagoons. Although lagoons can be designed with enough storage to minimize the
frequency of bottom sludge removals, at some point sludge accumulation will greatly
diminish the treatment capacity of most lagoons. Without the proper treatment volume,
anaerobic decomposition will be incomplete, and odors will usually become more
pronounced. Inadequate maintenance of treatment volume is the single most common reason
for the failure of lagoon treatment systems. The method used most frequently to remove
sludge entails vigorous mixing of sludge and lagoon water by means of an agitator/chopper
; 4-20
-------
pump or propeller agitator. The operation of the agitator/chopper must be continuously
monitored to prevent damage to the liner berms, or embankments, which could result in
contamination of surface or ground water. The sludge mixture is then pumped through an
irrigation system onto cropland.
Some lagoons are covered with a synthetic material. There can be multiple advantages to
covering a lagoon: A cover will prevent rainfall from entering the system, which can result in
additional disposal costs. Nitrogen volatilization is minimized, making the waste a more
balanced fertilizer and potentially saving expenses for the purchase of nitrogen fertilizers.
The EPA AgSTAR Program has demonstrated that biogas production and subsequent
electricity generation from covered lagoons and digesters can be cost effective, help control
odor, and provide for more effective nutrient management.
• Digesters. Conventional aerobic digestion is frequently used to stabilize biosolids at small
municipal and industrial facilities as well as at some animal feeding operations. Waste is
aerated for relatively long periods of time to promote microbial growth. Substantial
reductions intotal and volatile solids, biochemical and chemical oxygen demand, and organic
nitrogen as well as some reduction in pathogen densities can be realized. Autoheated aerobic
digesters use me heat released during digestion to increase reaction rates and allow for more
rapid reduction of pathogens. The biosolids created by digesters concentrate solids resulting
in easier handling. Additional information on the operational considerations, performance,
and advantages and disadvantages of digesters can be found in Section 8.
• Sequencing batch reactors. Manure is treated in sequence, typically in a vessel of metal
construction. The vessel is filled, reacted (aeration cycled on and off), and then allowed to
settle. Organic carbon and ammonia are reduced and phosphorus is removed through
biosolids generation or chemical precipitation. The biosolids generated are in a concentrated
form, allowing for ease in handling.
• Other. Many lother practices are used separately or in combination with the practices listed
above to treatswine wastes. Constructed wetland treatment cells, trickling filters,
composting, oxidation ditches, are a few of the other ways to treat swine wastes. Systems
being developed or under trial studies include Y- or V- shaped pits with scrapers for solid-
liquid separation at the source, membrane filtration, chemical treatments, high-rise hog
buildings, oligolysis, hydroponic cultivation, photosynthetic digesters, and closed loop water
use systems using ultraviolet disinfection. Information on the operational considerations,
performance, and advantages and disadvantages of these and other treatment practices can be
found in Section 8.
4.1.4.1 Waste Management Practices by Operation Size and Geographical Location
The use of a particular waste" management system is driven by the size of the operation and
geographic considerations (e.g., climate). For example, operation of a confined facility with the
use of a lagoon for treatment requires substantial capital investment. Below a certain number of
head, such a system would be cost-prohibitive since the high start-up and maintenance costs of
4-21
-------
such a facility have to be spread over a large number of animals to ensure economic viability.
Geographic considerations also play a role in waste management. Anaerobic lagoons are
common in the Southeast, where factors such as land availability and climate conditions are
favorable. Midwestern farms are more likely to use pit storage with slurry transport to
aboveground or belowground tanks.. The Swine '95 Survey (USD A APHIS, 1995) provides a
detailed picture of swine management practices by operation type, size, and location.
Waste Management Practice by Operation Size
As mentioned previously, large operations (greater than 2,000 head marketed in the past 12
months) are much more likely to use water for waste management than small operations.
Smaller operations (less than 500 head) typically manage waste by hand cleaning or mechanical
scraper/tractor. They also use pit-holding and [flushing systems because of their relatively lower
labor requirements. While larger operations also use pit storage and slurry storage in tanks, they
are far more likely to move waste from the housing facility to a lagoon. Tables 4-20,4-21, and
4-22 present the frequency of operations using the most common types of waste management
systems for swine farrowing, nursery, and finishing phases, respectively. Table 4-23 presents the
frequency of waste storage system use by size of operation. Table 4-24 presents the frequency of
waste storage system use by region for operations that marketed 5,000 or more hogs in a 12-
month period. It should be noted that the percentages do not add to 100 percent. This is because
an operation may use more than one waste storage system. For example, many large facilities in
the soxitheast have below floor slurry storage that is then moved to lagoon storage.
Table 4-20. Frequency (in percent) of Operations in 1995 by Type of Waste
Management System Used Most in the Farrowing Phase
Variable
None
Pit-holding
Scraper /Tractor
Hand cleaned
Flush - under slats
Flush - gutter
Other
Number of Hogs Marketed in Past 12 Months
<2,000 :
14.1
24.4
12.3
39.7
4.6 "
3.0
1.8
2,000-10,000
5.6
53.9
3.6
0.6
20.8
2.7
13
>10,000
1.7
49
6.0
0
39.3
2.6
1.5
Source: USDA APHIS, 1995
4-22
-------
Table 4-21. Frequency (in percent) of Operations in 1995 by Type of Waste
Management System Used Most in the Nursery Phase
Variable
None
Pit-holding
Scraper /Tractor
Hand cleaned
Flush - under slats
Flush - gutter
Other
Number of Hogs Marketed in Past 12 Months
<2,000
4.4
32.3
18.5
31.7
8.7
2.1
2.3
2,000 - 10,000
3.3
55
3.9
1.6
19.6
1.7
15
Source: USDA APHIS, 1995
>10,000
0
48 .
1.7
0
10.2
3.4
6.8
Table 4-22. Frequency (in percent) of Operations in 1995 by Type of Waste
Management System Used Most in the Finishing Phase
Variable
None
Pit-holding
Scraper /Tractor
Hand Cleaned
Flush -under slats
Flush - gutter
Other
Number of Hogs Marketed in Past 12 Months
<2,000
15.2
22.1
25.5
28.0
1.9
3.3
4.0
2,000 - 10,000
4.6
53
8.6
3.0
17.5
7.8
5.5
Source: USDA APHIS, 1995 ""
>10,000
0
45.3
11.4
0 •
30.0
6.0
7.4
4-23
-------
Table 4-23. Frequency (in percent) of Operations in 1995 That Used Any of the
Following Waste Storage Systems by Size of Operation
Waste Storage System
Below-floor slurry
Aboveground slurry
Belowground slurry
Anaerobic lagoon with
cover
Anaerobic lagoon without ,
cover
Aerated lagoon
Oxidation ditch
Solids separated from
liquids
Other
Percentage of Operations by Number of Head Marketed for Slaughter
<2,000 Head
43.6
4.1
17.3
2.2
17.4
1.3
2.9
4.1 i
0.6
2,000 - 10,OOQ Head
70.4
10.3
25.6
0.5
29.2
6.9
0.1
5.9
0.0
>10,000 Head
47.9
8.3
26.8
2.0
81.8
1.0
0.0
4.7
1.1
Source: USDA APHIS, 1995
With minor exceptions, there are consistent trends in operation management from one part of the
country to another. The multi-site model that separates production phases is being adopted
across the country; finishing age and number of litters per year already tend to be the same from
one part of the nation to another. With the exception of the Midwest, producers tend to farrow
small groups of sows weekly (USEPA, 1998). In the Midwest, some producers farrow only
twice a year, usually in the spring and fall. This is usually done on smaller operations, where
sows are maintained outdoors and then moved indoors for farrowing. The buildings in which
pigs are housed in the Midwest tend to differ from those in more temperate parts of the country,
and waste is managed differently in the Midwest than in other parts of the country. Confined,
three-site operations predominate in the Southeast, south-central region, and West, although there
are some smaller outdoor operations hi the south-central region and the West
4-24
-------
Table 4-24. Frequency (in percent) of Operations in 1995 That Used Any of the
Following Waste Storage Systems by Region for Operations That
Marketed 5,000 or More Hogs in a 12-Month Period
Waste Storage System
Below-floor slurry
Aboveground slurry
Belowground slurry
Anaerobic lagoon
Aerated lagoon
Solids separated from
liquids
USDA APHIS Region"
Midwest.
21.5
NA
NA
91.2
NA
NA
North
28.5
NA
NA
4.8
X"
NA
Southeast
85.7
27.2
43.3
33.3
NA
14.4
__ f 7 .7 ? —7 - ,•*•--*- .. ^y 1...U, **-»j v**j •*•**} t/w**ujw««jfc—iTj.v./j AV Ji j AA^S •Ll^'j VJ^T^ \Slliy tilt- IV UldJUL Lnjlfi. OUlLCO LUal aUbUUUUTU
for nearly 91 percent of U.S. hog inventory were surveyed.
b The standard error for the aerated lagoons in the northern region as evaluated by NAHMS exceeds 21 percent and was therefore determined by
NAHMS not to be statistically valid. Note that the aerated lagoon is reportedly found in roughly 70 percent of the operations in the north region.
Source: USDA APHIS, 1995
Most types of waste management systems are also similar across most regions with only minor
deviations. For example, the pit recharge systems with aboveground storage and land application
are nearly identical among farms in the Midwest, the south-central region, and the Northeast.
The primary waste management system that has the most variation among and within regions is
known as the hand wash system. Hand wash systems are found predominantly on operations
with fewer than 500 pigs; most of the operations using hand washing as their primary waste
management system have fewer than 100 pigs. On these operations, it is in the farrowing house
and/or nursery phases of production that hand washing is used to remove waste from the
buildings. Either the wash water exits the building and enters the environment directly or a
collection basin is located underneath or at one end of the building. In the case of collection, the
wash water is stored and used for land application at a later time or is allowed to evaporate over
time. Frequency of hand washing varies among operations from 3 times a day to once a week.
Another type of system identified as a primary waste management system on small operations in
the Midwest and New England (USDA APHIS, 1995) uses a flat blade on the back of a tractor to
scrape or remove manure from feeding floors. The popularity of this system apparently has
waned, and the system no longer represents a major means for removing wastes from swine
feeding operations (NCSU, 1998a).
4-25
-------
Swine Waste Management Systems in the Pacific Region
Descriptive information about the waste management systems in this region is provided in Table
4-25. In general, the region is characterized by operations with fewer than 500 pigs that use hand
washing and dry lots as their primary waste management system. In contrast, the majority of pigs
are raised on operations with more than 1,000 animals that use either deep pit/aboveground
storage or pit recharge/lagoon.
Table 4-25. Distribution of Predominant Waste Management
Systems in the Pacific Region8 in 1997
Farm Size
(number of pigs)
Fewer than 500
500 to 1,000
More than 1,000
i Primary Waste
Management System
1. Hand Wash/Dry Lots
2. Scraper/Aboyeground Storage/Land Application
1. Hand Wash/Dry Lots
2. Deep Pit/Aboyeground Storage/Land Application
1. Deep Pit/AboVeground Storage/Land Application
2. Pit Recharge/Covered Anaerobic Lagoon/Irrigation
'Alaska, California, Hawaii, Oregon, and Washington
Source: Adapted from NCSU, 1998a
Swine Waste Management Systems in the Central Region
Table 4-26 presents information for the Central region. It is the fastest-growing area of swine
production in the nation at the present time. As a result, large operations (>2,000 head) account
for almost all of the swine in these states. As a group, these large operations appear to rely on
evaporation from lagoons, aeration of anaerobic lagoons, or biogas production from lagoons as
the main means for storing and treating swine waste.
Circle 4, one of the largest operations in the country, uses a pit-recharge system that is emptied
about three times per week. Wastewater treatment is by a two-stage evaporative lagoon system.
The primary stage is designed for treatment of volatile solids, with additional volume for 20
years of sludge storage. The exact treatment volume design is operation- (or complex-) specific
and takes into consideration the diet, feed digestibility, and absorption arid conversion efficiency
of the animal for each group of confinement hbuses. The primary stage is sized on the basis of
volume per input of volatile solids plus an additional volume for 20 years of sludge storage. The
secondary stage lagoon volume and surface area are specified to allow evaporation of all excess
water not required for pit recharge. Waste management plans call for sludge removal on the
order of 20 years. Because the operation has not reached its design life at this time, this system
cannot be evaluated.
4-26
-------
Table 4-26. Distribution of Predominant Waste Management
Systems in the Central Region8 in 1997
Farm Size
(number of pigs)
Fewer than 500
500 to 1,000
More than 1,000
Primary Waste
Management System
1. Hand Wash/Dry Lots
1 . Flush or Pit Recharge/Anaerobic Lagoon/Irrigation
2. Deep Pit/Aboveground Storage/Land Application
1 . Flush or Pit Recharge/Aeration of Anaerobic Lagoon/Irrigation
2. Flush or Pit Recharge/Covered Anaerobic Lagoon/Land Application
3. Pit Recharge/Evaporation from Two-Stage System
' Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Oklahoma, Texas, Utah, Wyoming
Source: NCSU 1998a . ,
Swine Waste Management Systems in the Mid-Atlantic Region
Table 4-27 summarizes descriptive information for the region. Only North Carolina and
Pennsylvania grbw a significant number of swine. The medium and large operations rely on
either anaerobic, lagoons and wastewater irrigation or aboveground storage and land application
as their primary means of waste management. Operations in the remaining states typically have
fewer than 500 animals each, and they use hand washing in conjunction with dry lots as their
primary waste management system.
The design and operation of the anaerobic lagoon and irrigation system are different in the two
key states. In Pennsylvania, lagoon loading rates are lower to accommodate the lower
temperatures, arid storage requirements must be increased to accommodate the longer inactive
period during winter, Average yearly rainfall is about the same in the two states, with rainfall in
excess of evapptranspiration requiring increased storage requirements.
Table 4-27. Distribution of Predominant Waste Management
Systems in the Mid-Atlantic Region8 in 1997
Farm Size
(number of pigs)
Fewer than 500
500 to 1,000
More Than 1,000
Primary Waste
Management System
1. Hand Wash/Dry Lots
2. Gravity Drain/Collection Basin/Land Application
1. Deep Pit/Aboveground Storage/Land Application
2. Pit Recharge/Anaerobic Lagoons/Irrigation
3 . Scraper/Aboveground Storage/Land Application
1 . Deep Pit/Aboveground Storage/Land Application
2. Pit Recharge/Anaerobic Lagoons/Irrigation
• Connecticut, Delaware, Kentucky, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania,
Rhode bland, Tennessee, Vermont, Virginia, and West Virginia
Source: Adapted from NCSU 1998a
4-27
-------
Swine Waste Management Systems in the South Region
Table 4-28 summarizes descriptive information for the region. Large operations (more than
1,000 head) represent only a small fraction of tiie operations in the states of the region. The
predominant waste management system is a flush or pit-recharge system for removal of waste
from buildings, an anaerobic lagoon for treatment and storage of waste, and reincorporation of
treated wastewater back into the environment by irrigation. In these states, housing is usually
enclosed, with ventilation and a concrete floor surface.
Table 4-28. Distribution of Predominant Waste Management
Systems in the South Region8 in 1997
Farm Size
(number of pigs)
Fewer than 500
500 to 1,000
More Than 1,000
1
Primary Waste Management System
1. Hand Wash/Dry Lots
2. Scraper System/ Aboveground Storage/Land Application
1. Flush or Pit Recharge/Anaerobic Lagoon/Irrigation
1. Flush or Pit Recharge/Anaerobic Lagoon/Irrigation
•Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, and South Carolina
Source: Adapted from NCSU 1998a i
Swine Waste Management Systems in the Midwest Region
Table 4-29 summarizes descriptive information for this region. Small operations account for
most of the operations in this region; however, recent construction of large units in Iowa,
Minnesota, Missouri, and South Dakota indicate that the trend toward production in larger units
seen in the southeastern U.S. is probably occurring in the Midwest Region as well. Primary
waste management systems for operations with fewer than 500 pigs are hand wash coupled with
dry lots with and without collection basins. In contrast, medium and large operations rely on
storage of waste either under buildings with deep pits or in aboveground structures in
conjunction with direct land application for crop production.
Table 4-29. Distribution of Predominant Waste Management
Systems in the Midwest Region8 in 1997
Farm Size
(number of pigs)
Fewer than 500
500 to 1,000
More than 1,000
Primary Waste Management System
1. Hand Wash/Dry Lots
2. Hand Wash/Dry Lots and Collection Basin/Land Application
3. Deep Pit/Land Application
1. Deep Pit/Aboveground Storage/Land Application
2. Pit Recharge/Aeration of Anaerobic Lagoons/Irrigation
3. Deep Pit/Land Application
1. Deep Pit/Aboveground Storage/Land Application
2. Pit Recharge/Covered Anaerobic Lagoon/Irrigation
* Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin
Source: NCSU 1998a
4-28 -
-------
4.1.5 Pollution Reduction
4.1.5.1 Swine Feeding Strategies
Swine producers, use a variety of feed ingredients to achieve a balanced diet for a pig at each
phase of the animal's development. Various grain products, including corn, barley, milo, and
sometimes wheat form the foundation of the growing pig's diet and supply most of the
carbohydrates and fat. Oilseed meals are the primary source of protein, and they foster muscle
and organ development (NPPC, 1999). Producers also supplement the basic diet with minerals
and vitamins as rieeded. A pig's diet changes as the animal grows. For example, finishing pigs
typically receive a diet containing 13 to 15 percent crude protein versus the 20 to 22 percent
protein diet received by young pigs. The Swine '95 survey indicates that more than 96 percent of
grower-finisher operations use multiple diets from time of entry to market weight. Almost 70
percent of the operations feed their pigs three or more diets during this phase.
Swine operations can use feeding strategies both to maximize growth rates and to reduce
excretion of nutrients. The following feeding strategies can be used to reduce nitrogen and
phosphorus manure content.
Grinding. Fine grinding and pelleting are simple but effective ways to improve feed utilization
and decrease nitrogen and phosphorus excretion. By reducing the particle size, the surface area
of the grain particles is increased, allowing for greater interaction with digestive enzymes. When
particle size is reduced from 1,000 microns to 400 microns, nitrogen digestibility increases by
approximately 5 to 6 percent. As particle size is reduced from 1,000 microns to 700 microns,
excretion of nitrogen is reduced by 24 percent. The current average particle size is
approximately 1,100 microns; the recommended size is between 650 and 750 microns. Reducing
particle size below 650 to 750 microns greatly increases the energy costs of grinding and reduces
the throughput of the mill. The use of so small a particle size will also increase the incidence of
stomach ulcers in the hogs (NCSU, 1998b).
Amino Acid Supplemental Diets. Supplementing the diet with synthetic lysine to meet a
portion of the dietary lysine requirement is an effective means of reducing nitrogen excretion by
hogs. This process reduces nitrogen excretion because lower-protein diets can be fed when
lysine is supplemented. Research studies have shown that protein levels can be reduced by 2
percentage points when the diet is supplemented with 0.15 percent lysine (3 pounds lysine-
HC I/ton of feed) without negatively affecting the performance of grow-finish pigs. Greater
reductions in protein are possible, but only if threonine, tryptophan, and methionine are also
supplemented.
Table 4-30 shows the theoretical effect of feeding low-protein, amino acid-supplemented diets on
nitrogen excretion of finishing pigs. Note that reducing the protein level from 14 percent to 12
percent and adding 0.15 percent lysine results in an estimated 22 percent reduction in nitrogen
excretion. Reducing the protein further to 10 percent and adding 0.30 percent lysine, along with
4-29
-------
adequate threonine, tryptophan, and methionine, reduces the estimated nitrogen excretion by 41
percent.
Although it is currently cost-effective to use supplemental lysine and methionine, supplemental
threonine and tryptophan are currently too expensive to use in widespread diets. However,
because of rapid technological advances in fermentation procedures for synthesizing amino acids,
the price of threonine and tryptophan will likely decrease in the next few years.
Table 4-30. Theoretical Effects of Reducing Dietary Protein and Supplementing With
Amino Acids on Nitrogen Excretion by 200-lb Finishing Pig"*
Diet Concentration
NT balance
N intake, g/d
N digested and absorbed, g/d
N excreted in feces, g/d
N retained, g/d
N excreted in urine, g/d
N excreted, total, g/d
Reduction in N excretion, %
Change in dietary costs. $/tonb
14 Percent CP
67
60 .
7
26 ;
34 :
41
—
0 1
12 Percent CP + Lysine
58
51
7
26
•25
32
22
-0.35
10%CP + Lysime +
Threonine + Tryptopham
+ Methionine
50
43
7
26
17
24
41
+$14.50
' Assumes an intake of 6.6 Ib/d and a growth rate of 1.98 Ib/d. » Costs used L-Lysine HC1, $2.00/lb; com, $2.50/bushel; SBM, $250/ton; L-
Threonine, S3.50/Ib; DL-Methionine, S1.65/Ib; Tiyptosine (70:15, Lys:Tiyp) $4.70/lb.
Source: NCSU,1998b
Phase Feeding and Split-Sex Feeding. Dividing the growth period into more phases with less
spread in weight allows producers to more closjsly meet the pig's protein requirements. Also,
since gilts (females) require more protein than barrows (males), penning barrows separately from
gilts allows lower protein levels to be fed to barrows without compromising leanness and
performance efficiency in gilts. Feeding three or four diets, compared with only two diets, (luring
the grow-finish period would reduce nitrogen excretion by at least 5 to 8 percent (NCSU, 1998b).
Formulating Diets on an Available Phosphorus Basis. A high proportion (56 to 81 percent) of
the phosphorus in cereal grains and oilseed meals occurs as phytate. Pigs do not use phosphorus
in this form well because they lack significant amounts of intestinal phytase, the enzyme needed
to remove the phosphate groups from the phytate molecule. Therefore, supplemental phosphorus
is added to the diet to meet the pig's growth requirements.
i
Because some feedstuffs are high in phytate and because there is some endogenous phytase in
certain small grains (wheat, rye, triticale, and barley), there is wide variation in the bioavailability
of phosphorus in feed ingredients. For example, only 12 percent of the total phosphorus in corn
is available, whereas 50 percent of the total phosphorus in wheat is available. The phosphorus in
dehulled soybean meal is more available than the phosphorus in cottonseed meal (23 percent vs.
1 percent), but neither source of phosphorus is as highly available as'the phosphorus in meat and
4-30
-------
bone meal (66 percent), fish meal (93 percent), or dicalcium phosphate (100 percent) (NCSU,
1998b).
Supplementing Diets with Phytase Enzyme. Supplementing the diet with the enzyme phytase
is an effective means of increasing the breakdown of phytate phosphorus in the digestive tract
and reducing the phosphorus excretion in the feces. Using phytase allows one to feed a lower
phosphorus diet because the unavailable phytate phosphorus in the grain and soybean meal is
made available by the phytase enzyme to help meet the pig's phosphorus needs. Studies at
Purdue University, at the University of Kentucky, and in Denmark indicate that the inclusion of
phytase increased the availability of phosphorus in a com-soy diet threefold, from 15 percent up
to 45 percent.
A theoretical example of using phytase is presented in Table 4-31. If a finishing pig is fed a diet
with 0.4 percent phosphorus (the requirement estimated by NRC, 1988, cited in NCSU, 1998b),
12 grams of phosphorus would be consumed daily (3,000 grams times 0.4 percent), 4.5 grams of
phosphorus would be retained, and 7.5 grams of phosphorus would be excreted. Feeding a
higher level of phosphorus (0.5, 0.6, or 0.7 percent) results in a slight increase in phosphorus
retention but causes considerably greater excretion of phosphorus (10.3,13.2, and 16.2 g/d,
respectively). Being able to reduce the phosphorus to 0.3 percent hi a diet supplemented with
phytase would reduce the intake to 9 grams of phosphorus per day and would potentially reduce
the excreted phosphorus to 4.5 g/day (a 37 percent reduction in phosphorus excretion versus
NRC's estimate): The percent reduction hi excreted phosphorus is even more dramatic (56
percent) when one compares the 4.5 grams with the 10.3 grams of phosphorus excreted daily by
finishing pigs fed at the 0.5 percent phosphorus level typically recommended by universities and
feed companies. Bone strength can be completely recovered by supplementing a low-P diet with
1,000 phytase units per kilograms of feed, while most of the grain and feed efficiency is returned
to NRC levels. In addition to returning bone strength and growth performance to control levels,
there is a 32 percent reduction in phosphorus excretion. A summary of 11 experiments (Table 4-
32) indicates that all the growth rate and feed efficiency can be recovered with the dietary
supplementation of 500 phytase units and reduced-phosphorus diets. Some analyses have
suggested that a 50 percent reduction hi excreted phosphorus by pigs would mean that land
requirements for manure applications based on phosphorus crop uptake would be comparable to
manure applications based on nitrogen.
Table 4-31. Theoretical Effects of Dietary Phosphorus Level and
Phytase Supplementation (200-lb Pig)
Dietary P(%)
0.70
0.60
0.50
0.40 (NRC, 1988)
0.30
0.30 + Phvtase
Phosphorus (g/d)
Intake
: 21.0
18.0
: 15.0 -
12.0
9.0
9.0
Retained
4.8
4.8
4.7
4.5
2.5
4.5
Excreted
16.2
13.2
10.3
7.5
6.5
4.5
Change From Industry
Average (%)
+57
+32
0
-27
-37
-56
4-31
-------
Source: Cromwell and Coffey, 1995, cited in NCSU, 1998b. i'
Previously, phytase was too expensive to use as a feed additive. However, this enzyme can now
be effectively produced by recombinant DNA techniques and the cost has decreased. A cost
evaluation indicates that under certain conditions replacing dietary phosphorus of an inorganic
phosphorus source (e.g., dicalcium phosphate); with the phytase enzyme would be cost neutral.
Swine require that phytase supplements be fed at different levels based on the age of the pig
(Table 4-33). The different levels are based on phase of production and are likely related to the
digestive enzymes and cecum of the younger pig being less developed.
Table 4-32. Effect of Microbial Phytase on Relative Performance of Pigsa
Growth Response
ADG
ADFI
Feed Conversion Ratio
Negative Control
100
100
100
Positive Control
115 (+7-6.5)
105 (+/- 5.2)
93(+/-4.9)
Effect of 500+ Phytase
Units/kg
116.7 (+/ -10.6)
107.6 (+/- 7.8)
93.2 ("+/- 5.0)
* Eleven experiments with the negative control diets set at 100 percent and the relative change in pig growth performance to the confrol diets.
Source: Jongbloedetal., 1996, citedinNCSU,1998b
Table 4-33. Effect of Microbial Phytase on Increase in Phosphorus Digestibility by Age of
Pigs and the Recommended Rates for Inclusion of Phytase in Each Phase
Approximate
Increase (%)
Inclusion Level
(Phytase Unit/lb)
Nursery
13
454-385
Grower ;
17 1
385-227
Finisher
17
27-113
Gestation
7
227
Lactation
20
227
Source: JonWoed et al., 1996, cited in NCSU, 1998b
4.1.5.2 Waste and Waste Water Reductions
Methods to reduce the quantity of waste water generated at swine operations include advanced
swine watering systems to reduce water spillage and recycling water in waste flush systems. The
feeding strategies discussed in the previous section will also reduce the quantity of waste
generated by ensuring that animals do not receive more feed than required for optimal growth.
Additional information on feeding strategies for swine can be found in Chapter 8. Advanced
swine breeding has resulted in animals that produce less waste per pound of meat produced.
Nipple water delivery systems reduce the amount of waste water and are more healthy for the .
animals. Trough or cup waters are typically placed close to the floor of the pen. This allows the
animal to spill water and add contaminates to the standing water. Nipple water delivery systems
are placed higher in the pen and only deliver water to the animal when the animal is sucking on
the nipple. Watering systems may also use water pressure sensors and automatic shutoff valves
to reduce water spillage. The sensor will detect a sustained drop in water pressure resulting from
a break in the water line. The sensor will then stop the water flow to the broken line and an
alarm will sound. The operator can then fix the broken line and restore water to the animals with
;4-32
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minimal water spillage. There is little information about the relative use of the various water
delivery systems or the relative use of water pressure sensors and shutoff valves within the swine
industry.
The use of recycled water in swine flush and pull plug waste management systems will also
reduce the amount of waste water generated at an operation. To obtain recycled water of
appropriate quality an operation can use a variety of methods to remove pollutants from the
waste stream. Such methods include solid-liquid separation, digesters, and multiple-stage lagoon
systems. Multiple-stage lagoon systems or the use of an initial settling basin will allow settling
of solids and biological processes to occur that can result in high quality water. One large
operation in Utah claims to have a completely closed system in which all waste water is treated
in a multiple-stage lagoon system and them recycled back to the manure flush system.
4.1.6 Waste Disposal
Waste is disposed in either a liquid or solid form. Handling and disposal in a solid form has
several advantages the more concentrated the waste. Hauling costs are reduced as the water
content is reduced; however, most operations prefer to handle and dispose of waste in a liquid
form because of the reduced labor cost of handling the waste in this manner. Table 4-34 shows
the percentage of operations that use or dispose of manure and wastes as unseparated liquids and
solids. Tables 4-35 and 4-36 show the percentage of operations that are using the most common
disposal methods by USDA APHIS region.
Table 4-34. Percentage of Operations in 1995 That Used or Disposed of
Manure and Wastes as Unseparated Liquids and Solids
Operation Size
Operations marketing fewer than 5,000
hogs in 12 months
Operations marketing 5,000 or more
hogs in 12 months:
USDA APHIS Region"
Midwest
92.3
100
North
99.1
19.6b
Southeast
97.7
98.5
• Midwest=SD, ME, MN.ilA, IL; North=WI, Ml, IN, OH, PA; Southeas^=MO, KY, TO, NC, GA; Only the 16 major pork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
b The standard error on this measurement is 16.0, resulting in questions of its accuracy
Source: USDA NAHMS, 1999
4-33
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Table 4-35. Percentage of Operations in 1995 That Marketed Fewer Than 5,000 Hogs in a
12-Month Period and That Used the Following Methods of Use/Disposal by Region
Waste Disposal Method
Placed on own land
Given away
USDA APHIS Region"
Midwest
97.9
NA .
North
98.5
11.0
Southeast
96.8
2.6
• Midwest-,SD, NE, MN, IA, IL; North=WI, M^ IN, OH, PA; Southeast=MO, KY, TN, NC, GA; Only the 16 majorpork states that accounted
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA NAHMS, 1999
Table 4-36. Percentage of Operations in 1995 That Marketed 5,000 or More Hogs in a 12-
Month Period and That used the Following Methods of Use/Disposal by Region
Waste Disposal Method
Placed on own land
Sold
Given away
USDA APHIS Region"
Midwest
100
NA ;
NA
North
100
NA
NA '
Southeast
97.5
7.3
11.3
• Midwest=SD, NE, MN, IA, IL; North=WI, W, IN, OH, PA; Southeast==MO, KY, TN, NC, GA
Source: USDA NAHMS, 1999 ;
Transport and land application of manure nutrients are necessary to realize the fertilizer benefit
of such, nutrients. Surface application and injection are common means of land application for
slurry. Depending on the consistency of the nianure, several types of equipment are available to
apply the nutrients to the land. The common manure spreader is a low-maintenance, relatively
inexpensive piece of equipment. The spreader is designed for solids and thick slurries; however,
because of the characteristics of the equipment, the manure is hard to apply uniformly. This type
of spreader requires loading equipment and usually takes longer to empty small loads. A flexible
drag hose can be used on relatively flat landscapes. This system unloads the manure quickly,
although it normally requires two tractors and a power unit on the pump. A flexible drag hose
system is effective on regularly shaped fields, but the equipment is expensive. Tank wagon
applications are used for liquid manure. The vjragon is adaptable to either surface broadcast or
injection, depending on the situation. Tank wagons apply liquid manure uniformly and are self-
loading; however, the pump to discharge the manure requires a large amount of horsepower,
which can be taxing on the tractor. Soil compaction is normally associated with tank wagons,
and it usually takes longer to empty the storage facility. Tables 4-37 and.4-38 show the
percentage of operations that disposed of manure and waste on owned or rented land using
various methods. Operations may use more than one method, therefore columns do not add up to
100 percent.
4-34
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Table 4-37. Method of Manure Application in 1995 on Land by Operations
that Marketed Fewer Than 5,000 Hogs in a 12-Month Period
Variable
Irrigation
Broadcast
Slurry-surface
Slurry— sSubsurface
USDAAPfflS Region-
Midwest
47.6
18.4
33.0
X
North
11.2
57.8
55.7
26.6
Southeast
2.9
69.0
46.6
22.9
• Midwest=SD, NE, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA
Source: USDANAHMS, 1999
Table 4^-38. Method of Manure Application in 1995 on Land by Operations
That Marketed 5,000 or More Hogs in 12-Month Period
Variable
Irrigation
Broadcast
Slurry-surface
Slurry-subsurface
Region8
Midwest
100
X"
X"
X
North
74.8
X
6.3
23.6
Southeast
16.4
39.4
68.1
72.1
• Midwest=SD, NE, MN, IA, IL; North=WI, MI, IN, OH, PA; Southeast=MO, KY, TN, NC, GA
b Operations in this region also use broadcast and slurry-surface methods, but NAHMS determined the standard error was too high to report
statistically valid values.
Source: USDANAHMSi 1999
Most manure and waste is disposed of on land owned or rented by the operator, thus the amount
of land available for land application of wastes is critical. Applying too much manure and waste
to the same land year after year can result in a steady increase in the soil phosphorus content.
Tables 4-39 through 4-41 present the percentage of swine operations with and without adequate
crop and pasture|land for manure application on a nitrogen- and phosphorus-basis at plant
removal rates and operations that own no land. The operations that have "no land" were
determined by running queries of the USDA 1997 Census of Agriculture data to identify facilities
that did not grow any of the 24 major crops grown in the U.S. Operations with no land available
are assumed to haul their waste to land that can use the waste as a fertilizer resource.
4-35
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Table 4-39. Percentage of Swine Grow-Finish Operations With Sufficient, Insufficient, and
No Land for Agronomic Application of Generated Manure
Size (head)*
1-749
750-1,874
1,875-2,499
2,500-4,999
> 5,000
Total
Sufficient Land
Nitrogen
76.4
84.4
80.2
73.8
48.31
76.3
i
Phosphorus
67.38
68.19
56.56
44.15
15.53
60.78 i
Insufficient Land
Nitrogen
7.2
8.98
13.81
19.45
42.04
13.54
Phosphorus
14.54
23.55
34.66
49.27
69.48
28.11
No Land
18.7
15.5
16.46
17.79
21.97
18.1
Source: USDANASS, 1999c.
* Estimated by adding head sold in the last year to inventory and dividing the sum by 2.8 turns per year.
Table 4-40. Percentage of Swine Farrowing Operations With Sufficient, Insufficient, and
No Land for Agronomic Application of Generated Manure
Size (bead)
1-749
750-2,499
> 2,500
Total
Sufficient Land
Nitrogen
70.7
13.33
20
66.1
Phosphorus
57.77
0
0
53.1
Insufficient Land
Nitrogen
8.44 •
33.33
60
11
Phosphorus
21.33
46.7
80
24.1
No Land
20.9
' 53.33
20
22.9
Source: USDANASS, 1999c.
4-36
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Table 4-41. Percentage of Swine Farrow-Finish Operations With Sufficient, Insufficient,
and No Land for Agronomic Application of Generated Manure
Size (head)"
1-749
750-1,874
1,875-2,499
2,500-4,999
> 5,000
Total
Sufficient Land
Nitrogen
0
84,4
80.2
' 73.8
48.3
76.3
Phosphorus
67.4
68.2
56.6
44.2
15.5
60.8
Insufficient Land
Nitrogen
6.6
6
7.9
12.4
23.1
8.3
Phosphorus
15.6
22.2
31.5
42
55.8
23.8
No Land
17
9.6.
12
13.9
28.6
15.4
4-37
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Estimated by adding head sold in the last year to inventory and dividing the sum by 2.1 turns per year. Inventory includes the number of head
in the breeding herd.
Source: USDA'NASS, 1999c I
Another waste product of swine farms is animal mortality. Mortalities are usually handled in an
environmentally sound and responsible manner, but improper disposal may cause problems with
odors, pathogens, biosecurity, and soil and water contamination. The 1995 USDA APHIS Swine
95 study assessed the frequency of mortality disposal methods based on whether operations
marketed more or fewer than 2,500 head in the prior 6-month period. (An operation that sold
2,500 head in the last 6-months corresponds roughly to an operation with 1,000 to 1,500 animal
unit capacity.) Tables 4-42 and 4-43 show the percentage of operations by method of disposal
for those operations which specified at least one pig had died in the 6-month period.
Table 4-42. Method of Mortality Disposal on Operations That Marketed
Fewer Than 2,500 Hogs in a 6-Month Period in 1995
Method of disposal
Burial on operation
Bum on operation
Renderer entering
operation
Renderer at perimeter of
operation
Composting
Other
USDA APHIS Region"
Midwest
73.2
9.1
2.1
2.7
10.3
7.0
North
71.6
7.2
14.1
4.2
6.4
9.8
Southeast
46.6
15.2
38.7
8.7
13.0
6.8
fbrnearlySl percent of U.S. hog inventory were surveyed.
Source: USDANAHMS, 1999
4-38
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Table 4-43. Method of Mortality Disposal on Operations That
Marketed 2,500 or More Hogs in a 6-Month Period in 1995
Method of Disposal
Burial on operation
Burn on operation
Renderer entering
operation
Renderer at perimeter of
operation
Composting
Other
USDA APHIS Region"
Midwest
23.0
9.9
39.9
27.9
x ' • '.
3.4
North
21.0
10.2
50.1
23.2
X
X
Southeast
20.8
17.1
37.5
31.4
11.1
1.8
— —,_—, ,_.,.»_, -..*»». ., ij iri*, **-,, vii, * .n., wwumfc^iot—iviw, *\.i, Aii> J-'^j \jf\ \jw.y uic ID major porK states mat accounica
for nearly 91 percent of U.S. hog inventory were surveyed.
Source: USDA NAHMS^ 1999
4.2 Poultry Industry
Poultry feeding operations include facilities that confine chickens or turkeys for feeding or
maintenance for :at least 45 days in any 12-month period. These facilities do not have significant
vegetation in the confinement area during the normal growing season, thus pasture and grazing
operations are generally not included. Facilities at which poultry are raised may also include
other animal and agricultural operations such as grazing, egg processing, and crop farming.
The specific poultry sectors are discussed in the following sections:
• 4.2.1: Broilers, roasters, and other meat-type chickens
• 4.2.2: Layers and pullets
• 4.2.3: Turkeys
Up until the 1950s most of the nation's poultry production was conducted on small family farms
in the Midwest. Midwestern states provided favorable climatic conditions for seasonal
production of poultry and close proximity to major sources of grain feed. Eventually, with the
improvement of the transportation and distribution systems, the poultry industry expanded from
the Midwest to other regions. With the advent of climate-controlled systems, poultry production
evolved to a year-round production cycle. By 1997, the value of poultry production exceeded
$21.6 billion, and much of the poultry output was generated by corporate producers on large
facilities producing more than 100,000 birds (USDA NASS, 1998a).
The poultry industry encompasses several subsectors, including broilers, layers, turkeys, ducks,
geese, and several other game fowl. This section focuses only on broilers, layers, and turkeys,
4-39
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which account for more than 99 percent of the annual farm receipts from the sale of poultry
(USDANASS, 1998a).
Together the annual sales of broilers, chicken eggs, and turkeys generate almost 10 percent of the
value of all farm commodities. Although each of the poultry subsectors has experienced
significant growth in output over the past two decades, broilers remain the dominant subsector,
accounting for approximately 65 percent ($14.2 billion) of the $21.6 billion in poultry farm sales
during 1997. Sales of eggs and turkeys accounted for 21 percent ($4.5 billion) and 13 percent
($2.9 billion), respectively. More than 15 million metric tons of poultry meat were produced in
the U.S. during that year (USDA NASS, 1998c).
Poultry production (especially broiler production) is a highly integrated industry, and as a result,
management strategies at the facility level tend to be more similar than in other sectors of animal
feeding operations. Contract growing began in the South during the 1930s, and by the 1950s the
contracts had evolved to their current form. Thus, the integrated structure seenioday was in
place by the 1960s (Sawyer, 1971, cited in Aust, 1997). For example, more than 90 percent of all
chickens raised for human consumption in the U.S; are produced by independent farmers
working under contract with integrated chicken production and processing companies. The
company provides some inputs such as the birds themselves, feed, medication, and monitoring of
flock health by company service personnel. The farmer provides the grow-out buildings,
electricity, water, fuel, bedding material ("litter"), and his or her own labor and management
skill. The company provides the newly hatched chicks that the farmer raises to market age and
weight, giving them the feed provided by the company. The farmer is paid largely on the basis of
weight gained by the flock as compared with other flocks produced during the same span of time.
When the birds reach market weight, the company picks them up and takes them to processing
plants, where they are processed into food products. Most integrated companies are stand-alone
chicken operations, although some also produce turkeys.
The poultry industry has continued to evolve in terms of the type and number of birds it
produces. Genetically designed birds have been developed with the ability to mature quickly and
reach market weight or lay eggs more rapidly. This has resulted in increased efficiency and
overall poultry production. Facilities that grow the birds have incorporated the latest automated
technology for the feed and watering systems as well as ventilation systems. The technological
advances have transformed poultry raising into a modem, mechanized industry.
4.2.1 BroDer Sector
This section describes the following aspect of the broiler industry:
• 4.2.1.1: Distribution of the broiler industry by size and region
• 4.2.1.2: Production cycles of broilers
• 4.2.1.3: Broiler facility types and management
• 4.2.1.4: Broiler waste management practices
• 4.2.1.5: Pollution reduction ;
• 4.2.1.6: Waste disposal ,:
4-40
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National Overview •
Domestic broiler production has followed the same trend as swine and other livestock industries.
Production has shifted from geographically diverse, small, family-run operations to large
industrial production facilities concentrated in a few states. The number of broiler operations
was quite stable between 1992 and.1997, with operations decreasing slightly from 23,949 broiler
operations in 1992 to 23,937 operations in 1997, down less than 1 percent (USDA NASS,
1999b); however, between 1982 and 1992, more than 6,000 broiler operations, or 20 percent of
the industry's producers, went out of business. As shown in Table 4-44, although the number of
operations decreased over the past 20 years, total broiler production increased, with new large
operations more than compensating for the small producers who have left the industry.
Table 4-44. Broiler Operations and Production in the United States 1982-19978
Year
1982
1987
1992
1997
Operations
30,100
27,645
23,949
23,937
Production
3,516,095,408
4,361,198,301
5,427,532,92"!
6,741,476,153
Broilers are young chickens of the meat-type breeds, raised for the purpose of meat production. Estimates cover a 12-month period (Dec. 1
through Nov. 30) and exclude states with fewer than 500,000 broilers.
Source: USDA NASS, 1998a, 1998b
4.2.1.1 Distribution of Broiler Operations by Size and Region
EPA's 1974 CAFO Effluent Limitations Guidelines and Standards generally apply to broiler
operations with more than 100,000 birds and with continuous overflow watering systems, and to
broiler operations with 30,000 birds and with a liquid manure system. (See Chapter 2 for the'
definition of a CAFO, and Chapter 5 for a discussion of the basis for revisions to the poultry
subcategories.) Where numbers of birds are presented, all birds regardless of age (e.g., poult,
laying age, or pullet) or function (i.e., breeder, layer, meat-type chicken) are included unless
otherwise indicated in the text.
Large operations dominate broiler production. Although large production operations are
characteristic of other livestock industries, such as the swine sector, the consolidation of the
broiler industry began earlier and was well entrenched by the 1970s. By 1982, farms that
produced fewer than 2,000 birds per flock numbered only 2,811, or about 5 percent of the total.
This number decreased by two-thirds to about 1,000 farms a decade-later (Abt, 1998). Compared
with other livestock industries, such as swine, the broiler industry has the smallest proportion of
small operators. For example, the smallest hog operations still accounted for more than 60
percent of all hog producers in 1992.
4-41
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Regional Variation in Broiler Operations
Table 4-45 presents the 1997 distribution of broiler operations by region and operation size, and
Table 4-46 presents the average flock size for these operations. In addition to being dominated
by large producers, the broiler industry is concentrated in several states. Georgia, Arkansas, and
Alabama, all in the South Region are some of the largest broiler-producing states. Table 4-47
presents the distribution of total chickens by region and operation size. It is important to note
that operations with more than 90,000 birds accounted for more than 48 percent of the broilers
even though they represented only 11.3 percent of the broiler operations. Operations with fewer
than 30,000 birds represented almost 60 percent of the operations but accounted for less than 7
percent of the total birds.
Table 4-45. Total Number of Broiler Operations by Region and Operation Size in 1997
Region •
Central
Mid Atlantic
Midwest
Pacific
South
National
Number of Chicken Broiler Operations by Size Group "
(Operation Size Presented by Number of Birds Spot Capacity)
X)-30,000
3,046
5,113
7,910
1,244
3,403
20,716
>30,000-
60,000
412
2,105
207
41
3,597
6,362
>60,000-
90,000
325
1,055
96
38
2,327
3,841
>90,000-
180,000
274
842
141
42
1,980
3,279
>180,000
78
100
43
63
377
661
Total
4,135
9,215
8,397
1,428
11,684
34,859
•CentraMD, MT, WY, NV, UT, CO, AZ, MM, XX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY,
TO, NC; Midwest=ND, SD, MN, MI, WI, OH, IN, IL, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC,
FL
* Broilers are young chickens of the meat-type breeds, raised for the purpose of meat production. Estimates cover a 12-month period (Dec. 1
through Nov. 30) and exclude states with fewer than 500,000 broilers.
Source: USDA NASS, 1999c
4-42
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Table 4-46. Average Number of Chickens at
Broiler Operations by Region and Operation Size in 1997
Region*
Central
Mid Atlantic
Midwest
Pacific
South
National
Average Chicken Broiler Animal Counts b
(Operation Size Presented by Number of Birds Spot Capacity)
>0-30,000
1,494
6,178
830
608
12,538
4,158
>30,000-
60,000
44,224
44,193
47,357
44,041
43,998
44,187
>60,000-
90,000
73,084
73,590
75,821
73,695
73,776
73,717
>90,000-
180,000
119,026
115,281
118,611
132,560
117,581
117,347
>180,000
332,030
303,155
414,945
624,380
281,453
332,073
All
Operators
25,402
35,771
6,933
35,200
60,897
35,993
• Central=ED, MT, WY, NV, UT, CO, AZ, NM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY,
TN, NC; MidwestFND, SD, MN, MI, WI, OH, IN, TL, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, BO; South=AR, LA, MS, AL, GA, SC,
FL i "
b Broilers are young chickens of the meat-type breeds, raised for the purpose of meat production. Estimates cover a 12-month period (Dec. 1
through Nov. 30) and exclude states with fewer than 500,000 broilers.
Source: USDANASS, l999c
Table 4-47. Distribution of Chickens by Region and Operation Size in 1997
Region*
Central
Mid Atlantic
Midwest
Pacific
South
National
Percentage of Total Chicken Broiler Counts b
(Operation Size Presented by Number of Birds Spot Capacity)
>0-30,000
j 0.36
2.52
0.52
0.06
3.40
6.86
>30,000-
60,000
"1.45
7.41
0.78
0.14
12.61
22.41
>60,000-
90,000
1.89
6.19
0:58
0.22
13.68
22.57
>90,000-
180,000
2.60
7:74
1.33
0.44
18.56
30.67
>180,000
2.06
2.42
1.42
3.14
8.46
17.49
Total
8.37
26.27
4.64
4.01
56.71
100.00
•Central=ID, MT, WY^NV, UT, CO, AZ, NM, TX, OK; Mid-Atlantic=ME, NH, VT,NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY,
TN, NC; Midwest=ND, SD, MN, MI, WI, OH, IN, E, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC,
FL
b Broilers are young chickens of the meat-type breeds, raised for the purpose of meat production. Estimates cover a 12-month period (Dec. 1
through Nov. 30) and exclude states with fewer than 500,000 broilers.
Source: USDANASS, 1999c -
4-43
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4.2.1.2 Production Cycles of Broilers
Broilers are usually grown for 42 to 56 days depending on the market weight desired. Female
broilers can also be grown to lay eggs for replacement stock, and these females are called broiler
breeders. Roasters are usually grown separated by sex, with the females being harvested at 42
days of age and the males given the space in the entire house until they are sent to market several
weeks later (USEPA, 1998). Other meat-type chickens (capons, game hens) comprise less than 1
percent of chickens raised for meat. Since they are raised in a similar manner to broilers, albeit
with different market weights and ages, they are not usually differentiated in the data.
Chickens are produced to meet specific requirements of the customer which can be a retail outlet,
fast-food chain, or institutional buyer, among others. A broiler is considered any chicken raised
for meat products, though the industry further 61assifies chickens primarily by the size, weight,
and age of the bird when processed.
• Poussin - Less than 24 days of age and about 1 pound or less.
• Cornish Game Hens-Less than 30 days of age and about 2 pounds.
• Fast-food Broiler - 2 pounds 4 ounces to 3 pounds 2 ounces (mostly 2 pounds 6 ounces to 2
pounds 14 ounces) and less than 42 days of age.
• 3's and Up - 3 to 4 3/4 pounds and 40 to 45 days of age.
• Broiler Roaster - 5 to 6 pounds, hens usually 55 days.
• Broiler for De-boning - 5 to 6 pounds, males usually 47 to 56 days.
• Heavy Young Broiler Roaster - The typical "roaster," 6 to 8 pounds, less than 10 weeks.
• Capon - 7 to 9 pounds, surgically de-sexed male broiler, 14 to 16 weeks.
• Heavy Hens - spent breeder hens, 5 to 5 Vz pounds, 15 months of age.
4.2.1.3 Broiler Facility Types and Management
The most common type of housing for broilers, roasters, pullets, and breeding stock is some type
of enclosed housing with bedding derived from wood shavings, rice hulls, chopped straw, peanut
hulls, or other products, depending on availability. The bedding absorbs moisture and dilutes the
manure produced by the birds. Modern houses have an automatic feeding system to distribute
the feed, a closed water system (automatic) to deliver the water for the birds, and a ventilation
system to provide clean air. Some houses have side curtains that can be retracted to allow
diffusion of air. Ventilation is typically provided using a negative-pressure system, with exhaust
fans drawing air out of the house, and fresh air returning through ducts around the perimeter of
the roof. The ventilation system uses exhaust fans to remove moisture and noxious gases during
the winter season and excess heat during the summer. Advanced systems use thermostats and
timers to control exhaust fans. These houses are also commonly integrated with an alarm signal
to notify the operator of malfunctions and a back-up electric generator during power outages.
Broilers and Roasters. Houses for broilers arid roasters are usually 40 feet wide and 400 to 500
feet long and typically designed for 25,000 to 30,000 broilers per flock. Older houses may be
somewhat smaller, holding 20,000 to 25,000 birds. The houses contain an impermeable surface
for the floor, typically clay. Wood shavings are initially added to the houses to a depth of
4-44
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approximately 4 inches. Between flocks, a small amount of litter referred to as cake (compacted
and concentrated manure/litter mix) is removed and the remaining litter may be "top dressed"
with an inch or so of new bedding material.
Pullets. Pullets are young chickens, usually less than 20 weeks of age, often raised for the
purpose of egg production. Pullet houses are similar in construction to broiler houses. The
houses are usually 40 to 45 feet in width and 300 to 500 feet in length. Most pullet houses are
equipped with nipple, trough, or bell drinkers and often use mechanical feeders (drag chain,
trough, or pan) ib distribute feed to the birds. Pullets are usually raised on a floor covered with a
bedding source, 1 to 4 inches deep. This litter mixture is either removed after each flock (20 to
21 weeks) or used for a second flock. If the litter is used for a second flock, a small amount of
litter as cake is removed and the remaining litter is top dressed with an inch or so of new bedding
material. When the house is totally cleaned out, the litter is pushed to the center of the house and
a front loader places it in a litter spreader for land application or disposal. Regular and thorough
house cleaning is required to minimize disease transmission.
Breeders. Houses are usually 40 to 45 feet in width and 300 to 600 feet in length. Most of the
breeder houses contain two rows of slats for the birds to roost. The slats are panels of wood
elevated 18 to 24 inches and laid across supports. The slats are spaced 1 inch apart to allow the
feces material to fall to the floor. Equipment can access the center section of the house to aid hi
the clean-out between flocks. These slats cover two-third? of the entire length of the house along
the outside walls, with the center one-third of the building containing bedding litter.
The center third of the house is covered with 2 to 6 inches of a bedding source before young
breeder layers are placed in the breeder house. Drinkers, mechanical feeders, and nests are
placed over the slat section of the house, which allows most of the manure produced by the birds
to fall beneath the slat area, keeping the area accessible to the birds cleaner.
4.2.1.4 Broiler Waste Management Practices
This section summarizes waste management practices for broiler, breeding stock, pullets, and
roaster production facilities. Manure as excreted by the birds has a high water content, most of
which evaporates. A typical broiler house with capacity for 22,000 birds at a time will produce
120 tons of litter per year. The litter consists mainly of wood chips or other organic plant matter
even after it has been in place for a year (NCC, 1999).
Litter Clean-out Schedules. The litter (bedding and manure) of broiler, pullet, and roaster
houses is typically cleaned out completely once a year, although there is a trend toward less
frequent complete clean-outs. Between flocks, the feeders, waterers, and brooding equipment are
winched to the ceiling. A machine is often used to clean out any clumps of litter (termed caking
out) that may build up around waterers and feeders. When the broiler or roaster house is
completely cleaned out, the litter is typically removed with a front-end loader or bobcat to a
spreader truck or flail-type spreader. Spreader trucks are similar to lime-spreading trucks, with a
moving bed that empties onto large, round metal plates that distribute the litter for use as
4-45
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fertilizer nutrients for pasture and crops. The rate of application is controlled by the rate at which
the moving bed empties and the speed of the ttuck (NCSU, 1998).
The common clean-out frequency, in broiler breeder houses is once a year. When the house is
cleaned, all the equipment (including slats) is removed from the house to allow a front-end loader
to push all of the manure to the center litter section of the house. Then a front-end loader places
the mixture of manure and litter into a spreader for land application. A thorough cleaning after
each flock (essentially once a year) removes pathogens that could be transferred to the next: flock.
After removal of all organic matter, the house is disinfected.
Litter Storage. Litter is removed from houses in large quantities during annual clean-out. Thus,
operators that have land try to time the annual clean-out to coincide with the time land is
available for litter application. If this approach is successful, the facility will need only enough
storage for cake out during the rest of the year. Traditionally, operators stack litter outside, near
the poultry houses or at the edge of fields for spreading in the spring.
However, an increasing number of states are imposing restrictions on the outdoor storage of
waste, although the stringency of these requirements vary from state to state. For example, under
Virginia's Poultry Waste Management Program, stockpiled poultry litter must be (1) covered, (2)
located to prevent storm water runoff, and (3) separated a minimum of 3 feet from the seasonally
high water table or by the use an impermeable ibarrier. Maryland's requirements for outdoor
storage are less restrictive and require only that storage be conducted in manner to be protective
from rainfall and runoff. The State of Delaware, which is also an important producer of poultry,
is less restrictive than Maryland and allows for uncovered storage of poultry litter (Hansen,
2000).
i
There are several methods for storing poultry litter ranging from open stock piles to roofed-
storage structures. The size and type of method employed varies with location and size of the
operation as well as applicable regulations. Open stockpiles are the least expensive alternative,
but pose the greatest risk of contaminating the surrounding environment. Contamination risk is
reduced if these stockpiles are put on top of ground liners. Other storage structures include
bunker-type storage structures, which are permanent aboveground concrete slabs with two
parallel walls of concrete identical to those used for storing silage on livestock farms (Brodie et
al., 2000). Storage structures with permanent roofs offer both advantages and disadvantages.
These structures eliminate the need for plastic povers and reduce the risk of runoff
contamination; however, they require a higher level of investment and higher maintenance costs
than the other types of structures. Also if these roof structures are not high enough, compacting
becomes more difficult and reduces the operator's ability to use the full capacity of the structure
(Goan, 2000).
j '
I
4.2.1.5 Pollution Reduction
New technologies in drinking water systems result in less spillage and are equipped with
automatic shutoff valves that help ensure that broiler litter stays drier. Feeding strategies reduce
the quantity of waste generated by ensuring that broilers do not receive more feed than required
4-46
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for optimal growth. State regulations have also driven many broiler operations to handle
mortalities in ways other than burials such as rendering and composting, which are increasing
(see Section 4.2.1.6).
Nipple water delivery systems reduce the amount of wasted water and are healthier for the
animals. Trough or bell type watering devices allow the animal to spill water and add
contaminants to the standing water. Nipple water systems deliver water only when the animal is
sucking on the nipple. Watering systems may also use water pressure sensors with automatic
shutoff valves to reduce water spillage. The sensor will detect a sustained drop in water pressure
resulting from a break in the water line. The sensor will then stop the water flow to the broken
line and an alarm will sound. The operator can then fix the broken line and restore water to the
animals with minimal water spillage.
Feeding strategies that reduce nitrogen and phosphorus can reduce the quantity of nutrients in the
excreta. Dietary strategies designed to reduce nitrogen and phosphorus include enhancing the
digestibility of feed ingredients, genetic enhancement of cereal grains and other ingredients
resulting in increased feed digestibility, more precise diet formulation, and improved quality
control. Although nitrogen and phosphorus are currently the focus of attention, these strategies
also have the potential to decrease other nutrients. Phytase is commonly added to broiler feed.
Phytase additions are expected to achieve a reduction in phosphorus excretion of 20 to 60 percent
depending on the phosphorus form and concentration in the diet (NCSU, 1998b). Protein
content, calcium, other mineral content, vitamin B, as well as other factors identified in the
literature influence the effectiveness of phytase use in feed. Additional information on feeding
strategies for broilers can be found in Chapter 8.
Feeding Strategies. Phosphorus excretion can be reduced by improving the utilization of feed
nutrients through; genetic improvements in poultry or by improving the availability of nutrients in
the feed ingredients through processing or genetics. Absorption of some minerals is relatively
poor and is dependent on the chemical form in the feed or supplement.
4.2.1.6 Waste Disposal
This section summarizes waste disposal practices for poultry production facilities. The two
major categories of poultry waste are manure or litter (manure mixed with bedding) and dead
animals. There is little variation in manure characteristics, but the litter composition varies by
storage, composting management, and other practices. Poultry litter can be disposed of in several
ways including land application, animal feed, and incineration. Waste may be pelletized before
its applied to the land. Pelletizing produces a more uniform product that is lighter, easily
transported in bulk, and spread more uniformly. Additional information on pelletizing poultry
wastes and other waste disposal methods can be found in Chapter 8.
Land Application of Poultry Litter. Land application of poultry litter recovers nutrients that
otherwise would be lost and improves crop yields. Poultry manure slowly releases its nutrients,
so annual applications are possible. Composting and bagging a pelleted poultry manure fertilizer
produces a marketable product for the commercial horticulture industry. One main obstacle to
4-47 •
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greater commercialization of poultry manure as a fertilizer product has been the inconsistency in
product quality from one facility to another.
Where land application is employed, operators commonly use broadcast spreaders and flail-type
spreaders for litter. Recommended application rates are based on the nutrient content of the
litter, crop type and yield goals, and current soil conditions.
Many producers with cropland apply their litteir to their own crops. However, as operations have
increased in size and have become more specialized, this option is becoming more limited. In
some cases, poultry production provides supplemental income to an otherwise small or non-
agricultural household with little or no land. Further exacerbating the problem of poultry litter
disposal is the fact that many areas of chicken production have a surplus of nutrient supply over
crop needs (USDA NRCS, 1998). In these areas, the poultry producers face difficulties in selling
litter, giving litter away, or even paying local farmers to take the litter. The percentage of broiler
operations with enough land and without enough land for application of manure on a nitrogen-
and phosphorus-basis and operations with no land are shown in Table 4-48. The facilities that
have ^'no land" were determined by running queries of the USDA 1997 Census of Agriculture
data to identify facilities that did not grow any of the 24 major crops grown in the U.S. More
details on the national and county level nutrient balance are found in Chapter 6.
Table 4-48. Percentage of Broiler Dominated Poultry Operations With Sufficient,
Insufficient, and No Land for Agronomic Application of Generated Manure
Capacity
(Number of
Birds)
1-29,999
30,000-59,999
60,000-89,999
90000-179,999
> 180,000
Total
Sufficient Land
Nitrogen
11.92
6.38
4.78
4.42
3.63
5.39
Phosphorus
9.6
2.9
2.1
1 ;
0.7
2.3
Insufficient Land
Nitrogen
37.7
53.52
57.39
64.16
68.93
59.97
Phosphorus
40.07
56.99
6.008
67.62
7.19
62.69
No Lund
50.37
40.09
37.82
31.41
27.43
35.02
Source: USDA NASS, 1999c
Use of Poultry Litter as Animal Feed. Dataion the use of poultry litter as animal feed is
inadequate to determine how prevalent it is as a waste disposal method. Anecdotal information
indicates that use of poultry litter as a food supplement for beef herds may be common in the
Mid-Atlantic and Southeast regions.
Incineration of Poultry Wastes. Incineration of poultry wastes is not dpne on a large scale in
the U.S. The practice is being successfully implemented in the United Kingdom and is actively
4-48
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being investigated in the U.S. Additional information on centralized incineration of poultry
wastes is presented in Chapter 8.
Disposal of Dead Animals. Concerns about possible ground water pollution from the burial of
dead birds have caused the poultry industry to search for alternatives for dealing safely with dead
stock. The most common methods of disposal of dead birds are composting, incineration, burial
in deep pits, rendering, and disposal in landfills. Anecdotal information indicates that some
broiler integrators have begun to distribute freezers to grower operations to store dead birds prior
to pick up for rendering. Technical information on practices for the disposal of dead animals is
presented in Chapter 8. However, there is little information available on the relative use of these
practices within the broiler industry.
4.2.2 Layer Sector
This section describes the following aspect of the layer industry:
• 4.2.2.1: Distribution of the layer industry by size and region
• 4.2.2.2: Production cycles of layers and pullets
• 4.2.2.3: Layer facility types and management
• 4.2.2.4: Layer waste management practices
• 4.2.2.5: Egg processing and wash water
• 4.2.2.6: Pollution reduction
* 4.2.2.7: Waste disposal
National Overview. Trends in the egg production subsector have paralleled those in other
livestock industries—increasing overall production on fewer and larger farms. At the end of
1997, there were 69,761 operations with hens and pullets of laying age in the U.S. (layers 20
weeks and older). This number represents a 19 percent decrease from the estimated 86,245
operations with egg-producing birds in 1992 (USDA NASS, 1999c). In the ten-year period from
1982 to 1992., the; number of operations with hens and pullets declined from more than 212,000,
a 60 percent decrease (Ab't, 1998). Table 4-49 shows the number of operations and bird
inventory for 198^, 1987,1992, and 1997. The number of operations in each category of
operation has decreased substantially while total production has increased. Table 4-49 also
provides data on operations and inventory with birds below laying age. As with other sectors,
specialization of production has gained a foothold, with a small but increasing number of
operations producing only pullets.
One major difference between the layer and egg production sector and the broiler production
sector is geographical distribution. Layer production, although primarily performed in 10 states,
is much less geographically concentrated than the broiler industry. Hence, the key regions
identified for the broiler industry in the previous section are not applicable to the layer and egg
production sector. Overall, layer production has not increased as rapidly as has broiler
production has.
4-49
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Table 4-49. Operations With Inventory of Layers or Pullets 1982-1997.
Total
Number of
Farms with
Layers 20
weeks and
older
Layer and
pullets 13
weeks and
older
Pullets
between 13
and 20
weeks old
Pullets less
than 13
weeks
1997
Ops
69,761
72,616
13,180
5,122
Production
313,851,480
366,989,851
53,138,371
51,755,985
1992
Ops
86,245
88,235
14,818
4,938
Production
301,467,288
351,310,317
49,843,029
i
44,567,993
1987
Ops
141,880
144,438
19,639
6,753
Production
316,503,065
373,577,186
57,074,121
47,409,798
1982
Ops
212,608
215,812
28,109
8,726
Production
310,515,367
362,464,997
51,949,630
40,705,085
Source: USDA NASS, 1999b
4.2.2.1 Distribution of Layer Operations by Size and Region
Layers are defined as chickens maintained for the production of table eggs. Eggs may be
produced for human consumption in the shell iform (sold in cartons) or may be used in the
production of liquid, frozen, or dehydrated eggs. Laying hen operations include facilities that
confine chickens for feeding or maintenance for at least 45 days in any 12-month period. These
facilities do not have significant vegetation in the confinement area during the normal growing
season. Facilities that raise pullets are generally included. Egg washing and egg processing
facilities located at the same site as the birds are generally included. Facilities that have laying
hen or pullet feeding operations may also include animal and agricultural operations such as
grazing and crop farming.
EPA's 1974 CAFO Effluent Limitations Guidelines and Standards generally apply to laying hen
operations with more than 100,000 birds and with continuous overflow watering systems, and to
laying hen operations with 30,000 birds and with a liquid manure system. (See Chapter 2 for the
definition of a CAFO, and Chapter 5 for a discussion of the basis for revisions to the poultry
subcategories.) Where numbers of birds are presented, all birds regardless of age (e.g., poult,
laying age, or pullet) or function (i.e., breeder, layer, meat-type chicken) are included unless
otherwise indicated in the text.'
Table 4-50 presents the number of layer, pullet, and combined operations by size class as well as
the average bird count at each type of operation. Table 4-51 presents the number of operations
with laying hens by operation size and region, and Table 4-52 presents the average number of
birds at these operations. Data on the three types of operations were obtained through special
queries of the 1997 Census of Agriculture (USDA NASS, 1999c). Each operation is uniquely
4-50
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characterized, thus the sum of all three provides the total number of operations with layers or
pullets or both (75,172 total operations). Pullet operations were assumed to be evenly distributed
so as to support layer operations. Thus the percentage of operations in a region from Table 4-51
is used to estimate the percentages of all layer and pullet operations in that region. Table 4-53
presents the distribution of egg laying chickens by facility size and region. It is important to note
that in 1997 the 326 largest operations with laying hens were less than one half of a percent of
the total operations (70,857) but had over 55 percent of the laying hens.
Table 4r50. Number of Operations in 1997 and Average Number of Birds at
Operations with Layers or Pullets or Both Layers and Pullets in 1997
National
Item
Layer Ops
Layer Count
Pullet Ops a
Pullet Count
Layer and
Pullet Ops
Layer and
Pullet Count
Number of Layer, Pullet, and combined Layer and Pullet Operations and Average Bird
Counts
(Operation Size Presented by Number of Birds Spot Capacity)
>0-30,000
57,413
926
3,694
5,010
12,011
218
>30,000-
62,500
528
43,621
516
51,162
67
. 45,963
>62,500-
180,000
419
103,048
61
133,303
•93
112,377
>180,000-
600,000
146
311,189
>600,000
25
1,013,318
44
305,679
91
358,580
64
1,367,476
Total
58,531
4,315
12,326
* Pullet size ranges vary from the others: X)-30,000; >30,000-100,000; >100,000-180,000; and>180,000.
Source: USDANASS, 1999c
4-51
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Table 4-51. Number of Operations in 1997 With Laying Hens by Region and Operation
Size in 1997
Region •
Central
Mid Atlantic
Midwest
Pacific
South
National
Number of Chicken Egg Laying Operations
(Operation Size Presented by Number of Layers in Inventory)
X)-30,000
15,067
17,445
23,069
6,509
7,334
69,424
>30,000-
62,500
76
150
123
38
208
595
>62,500-
180,000
41
133
1;82
66
90
512
>180,000-
600,000
28
48
78
, 39
44
237
>600,000
9
15
39
17
9
89
Total
15,221
17,791
23,491
6,669
7,685
70,857
•CentraWD, MT, WY, NV, UT, CO, AZ, MM, XX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY,
TN, NC; Midwest=ND, SD, MN, MI, Wf, OH, IN, IL, IA, MO, ME, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC,
FL
Source: USDANASS, 1999c :
Table 4-52. Average Number of Chickens at Operations in 1997 With
Laying Hens by Region and Facility Size
Region1
Central
Mid Atlantic
Midwest
Pacific
South
National
-
Average Chicken Egg Layer Counts
(Operation Size Presented by Number of Layers in Inventory)
>0-30,000
311
911
281
115
3,654
787
>30,000-
62,500
42,360
42,588
45,244
43,613
38,642
41,786
>62,500-
180,000
89,688
| 95,585
97,848
99,354
97,413
96,595
>180,000-
600,000
317,725
286,946
279,202
277,755
293,512
287,740
>600,000
733,354
1,007,755
1,229,095
813,356
884,291
1,027,318
AH
Operations
1,779
3,590
4,236
5,041
8,390
4,072
•CentraMD, MT, WY, NV, UT, CO, AZ, NM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, ICY,
TN, NC; Midwest=ND, SD, MN, MI, WI, OH, IN, IL, IA, MO, ME, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC,
FL
Source: USDA NASS, 1999c
4-52
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Table 4-53. Distribution of Chickens at Operations in 1997 With
Laying Hens by Region and Facility Size
Region8
Central
Mid Atlantic
Midwest
Pacific
South
National
Percentage of Total Chicken Egg Layer Counts
(Operation Size Presented by Number of Layers in Inventory)
X)-30,000
1.62
5.51
2.25
0.26
9.29
18.92
>30,000-
62,500
1.12
2.21
1.93
0.57
2.79
8.62
>62,500-
180,000
" 1.27
4.4.1
6.15
2.27
3.04
17.14
>180,000-
600,000
3.08
4.77
7.55
3.75
4.48
23.63
>600,000
2.29
5.24
1-6.61
4.79
2.79
31.69
Total
9.38
22.14
34.49
11.65
22.34
100.00
• Central=ID, MT, Wf, NV, UT, CO, AZ, NM, IX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, M, CT, NJ, PA, DE, MD, VA, WV, KY,
TN, NC; Midwest=ND, SD, MN, MI, WI, OH, IN, IL, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC,
FL
Source: USDANASS, 1999c
4.2.2.2 Production Cycles of Layers and Pullets
A layer is a sexually mature female chicken capable of producing eggs. Egg production can be
divided into two types, table and hatching. Table eggs are used for consumption, and hatching
eggs are used to supply broiler or layer production operations.
Traditionally, layers are kept through 1 year of egg production and sold for meat at 18 to 20
months of age. Depending on market conditions (relative price of eggs to hens), it has become
increasingly common to recycle layers through more than 1 year of production (Bradley et al.,
1998). Producers will recycle their flocks into a second or even a third cycle of lay. Flock
recycling involves stopping the flock's egg production, allowing a suitable rest period, and then
bringing the flock back into production. The entire process (called "force molting") of recycling
layers takes approximately 4 to 5 weeks. Producers stop egg production by reducing the length
of day (lighting) and feed supply. This period typically takes 2 to 4 weeks and involves a 7-day
fast followed by a period during which the flock is fed a low calcium diet. After this "rest
period," the flock is returned to normal lighting conditions and a nutritionally balanced diet to
support egg production (UCD, 1998). Once the flock is brought back into production, most layers
will meet or exceed original levels of egg production. Under this regime, the flock's life is
extended for 6 to 12 additional months.
4-53
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4.2.2.3 Layer Facility Types and Management
Litter-based Housing. A few litter and slat/litter houses are used to produce table eggs, These
same housing systems are used for the breeders that produce fertile eggs for the production, of
hatching eggs, which eventually replace the current flock of egg layers.
Non-litter Based Housing. Layers are often raised in cages arranged in two or four decks. Cages
have been the preferred way of housing table egg layers since the mid-1940s (Bradley et al.,
1998). They are popular because they provide good sanitation. When the birds are caged, flock
nutrition can be better managed and products (eggs) kept cleaner. Cages are designed to separate
the layers from their own feces and thereby eliminate many of the feces-related parasite and
health problems. Most commercial layer facilities employ one of the following designs.
High-rise Cage Systems. Cage systems are two-story poultry houses with cages for the laying-
hens in the top story suspended over the bottom story, where the manure is deposited and stored.
The house structure itself is usually 40 to 60 feet wide and from 400 to 500 feet long. The '
watering system is a closed (noncontinuous flow) nipple or cup system. The ventilation system
is designed so that the external air is brought into the top story, through the cages where the birds
are lopated, and then over the manure in the bottom story, exiting through fans in the bottom
story side wall. The ventilation system is designed to dry manure as it is stored. With proper
management of waterers to prevent water leaking to the bottom story, layer waste commonly has
a moisture content of 30 to 50 percent
Scrape-out and Belt Systems. Housing facilities for scrape-out and belt manure removal cage *
systems are the same dimensions as high-rise units except they have only one story. Watering
systems in these operations are also closed, using nipple or cup waterers. Ventilation varies from
fan-controlled to adjustable curtains in the side wall.
Cages in the scrape-out system are suspended over a shallow pit, which is scraped out to the end
of the house by a small tractor or a pit scraper. Belt systems have a continuous belt under the
different tiers of cages that moves the manure to the end of the house, where it is placed into a
field spreader or some other suitable storage device. Some of the newer belt systems move air
over the manure on the belt in an attempt to dry the manure before it is removed.
The manure from scrape-out and belt systems usually has a moisture content of between 70 and
85 percent. Therefore, the manure can be handled as a slurry, which is either injected or land
applied to the land with a spreader that can handle the high-moisture manure.
Flush-Cage Housing. Housing, equipment, and ventilation in flush-cage housing are similar to
the scrape-out system with the exception of how the manure is handled. Cages are suspended
over a shallow pit as in the scrape-out system, but water is used to move the manure from under
the cages to the end of the house, where the water and manure mixture is placed in an anaerobic
lagoon. The water used to flush the manure pits is recycled from the lagoon. A variation of this
system consists of solids separation by means of a primary lagoon and a secondary lagoon.
(NCSU, 1998a).
4-54
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Although storage, management, and disposal practices are quite similar for broiler and layer
operations, with the exception of layer operations using lagoon systems, there are regional
differences in how operations manage waste. A survey conducted by the United Egg Producers
during 1998 indicated significant regional differences in the way layer wastes are managed.
These differences are shown in Table 4-54. This data was used with the data in Table 4-51 to
estimate that the total number of layer operations that use water to move the wastes to a lagoon
(referred to as wet layer systems) was approximately 3,100 operations.
Table 4-54. Summary of Manure Storage, Management, and Disposal
Practice
Storage sheds in addition to high-rise housing
Housing with 6-month or longer storage of dry
manure . ' . .
Export or sale of some or all of litter
Litter use other than land application
(incineration, pelletization)
Farms with wet storage systems, such as
lagoon
Percentage of Region With Practice
Pacific
0
75
100
0
0
Central
0
40
40
0
60
Midwest
10
90
100
5
2
Mid-
Atlantic
0
90
75
5
5
South
• o
40
50
0
60
4.2.2.4 Layer Waste Management Practices
Manure handling systems vary by region. In 1999 the USDA's Animal and Plant Health
Inspection Service completed the Layers '99 Study (USDA APHIS, 2000b), which looked at a
15-state target population to develop information on the nation's table egg layer population. The
15 states accounted for over 75 percent of the table egg layers in the U.S. on December 1,1998.
The information collected was summarized by four regions. The data collected on the manure
handling methods of layer facilities are presented in Table 4-55.
4-55
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Table 4-55. Frequency of Primary Manure Handling Method by Region
Primary Manure
Handling Method
High-rise (pit at ground level
with house above
Deep pit below ground
Shallow pit (pit at ground
level with raised cages)
Flush system to lagoon
Manure belt '
Scraper system (not flush)
Total
Great Lakes
%
63.0
0.0
23.4
0.0
13.6
0.0
100
SE
12.3
—
9.6
—
6.7
_•.
Southeast
%
31.4
-0:0
19.9
41.0
43
2.5
100
SE
6.0
-
7.3
5.9
2.1
2.1
Central
%
48.1
6.4
1.6
0.0
20.2
23.7
100
SE
6.0
3.9
1-2
-
4.9
8.7
West
%
7.8
7.3
24.1
12.0
5.2
43.6
100
SE
2.1
2.5
7.2
3.6
1.5
6.4
All Farms
%
39.7
2.9
18.9
12.5
10.6
15.4
100
SE
4.4
1.0
4.4
2.5
2.7
2.6
Regions: Great Lakes: IN, OH, and PA; Southeast: AL, FL» GA, and NC; Central: AR, IA, MM, MO, and NE; West: CA, XX, WA.
SE = Standard Error '
Source: USDA APfflS, 2000b i
4.2.2.5 Layer Egg Wash Water
The majority of eggs marketed commercially in the U.S. are washed using automatic washers.
Cleaning compounds such as sodium carbonate, sodium metasilicate, or trisodium phosphate,
together with small amounts of other additives, are commonly used in these systems. In addition,
plants operating under the Federal Grading Service are required to rinse eggs with a sanitizer
following washing (Moats, 1981). Wash water is contaminated with shell, egg solids, dirt,
manure, and bacteria washed from the egg surface into the recycled water.
, A study by Hamm et al. (1974), performed to characterize the wastewater from shell egg
washers, calculated the pollutant load from 11 egg grading and egg breaking plants. Median
waste concentrations in the wash waters at the grading plants were found to be 7,300 mg/L for
chemical oxygen demand, 9,300 mg/L for total solids, and 4,600 mg/L for volatile solids; median
concentrations at the breaking plants were found to be 22,500 mg/L for chemical oxygen
demand, 27,000 mg/L for total solids, and 16,600 mg/L for volatile soilds.
Eggs may be washed either on farm or off farm. Operations that wash their eggs on farm may do
so in-line or off-line. The frequency of the egg processing location is presented in Table 4-56.
The frequency of egg processing location by operation size is presented in Table 4-57. The eggs
from over 80 percent of the operations are processed off site. Operations with fewer than
100,000 layers are more likely to have their eggs processed off site. Smaller poultry operations
primarily haul their wash water to treatment centers or sell their eggs to larger operations for
washing and processing (Thome, 1999). On the other hand, larger egg production operations
• 4-56
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collect and store egg wash water on site in large tanks or lagoons for treatment and storage. This
lagoon water may then be applied to fields using spray irrigation. These anaerobic lagoons are
earthen structures designed to provide biological treatment and long-term storage of poultry layer
waste. Treatment of waste occurs anaerobically, a process in which organic material is
decomposed to carbon dioxide and water, while stabilized products, primarily humic substances,
are synthesized. Where space is available, two-stage lagoons may be constructed for better
wastewater treatment and greater management flexibility. The first stage thus contains only the
treatment (permanent) volume and sludge volume while the second stage lagoon stores treated
wastewater for irrigation and provides additional treatment that produces a higher quality effluent
for recycling as flush water (Tyson, 1996).
Table .4-56. Percentage of Operations by Egg Processing Location and Region
Primary Egg
Processing Location
On farm in-line
On farm off-line
Offfarm
Total
Great Lakes
%
17.8
6.7
75.5
100
SE
8.4
5.4
8.1
-
Southeast
%
13.1
0.6
86.3
100
SE
4.3
0.6
4.4
-
Central
%
9.0
3.3
87.7
100
SE
3.2
3.3
4.5
-
West
%
10.9
9.3
79.8
100
SE
2.4
2.4
3.6
-
All
%
13.5
5.3
81.2
100
SE
3.0
2.1
3.2
_ .
SE = Standard Error :
Source: USDA APHIS, 2000b
Table 4-57. Percentage of Operations by Egg Processing Location and Operation Size
Primary Egg
Processing Location
On farm in-line
On farm off-line
Offfarm
Total
Egg Laying Operations with
<100,000 Layers
%
4.3
5.2
90.5
100
SE
2.8
3.1
4.1
—
Egg Laying Operations with 100,000+
Layers
%
28.9
5.5
65.6
100
SE
5.6
1.9
6.0
_
Regions: Great Lakes: IN, OH, and PA; Southeast: AL, FL, GA, and NC; Central: AR, IO, MN, MO, and NE; West: CA, TX, WA.
SE = Standard Error
Source: USDA NAHMS, 2000
4.2.2.6 Waste and Wastewater Reductions
: F
Methods to reduce the quantity of wastewater generated at layer operations include advanced
watering systems to reduce water spillage and feeding strategies. The use of feeding strategies
will reduce the quantity of waste generated by ensuring that animals do not receive more feed
than required for pptimal growth, Dietary strategies to reduce nitrogen and phosphorus content
4-57
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include developing more precise diets and improving the digestibility of feed ingredients through
the use of enzyme additives and genetic enhancement of cereal grains. Information on feeding
strategies for layer operations can be found in Chapter 8.
There are several types of water delivery systems used in layer operations. Nipple water delivery
systems reduce the amount of wastewater and result hi healthier birds. Trough or cup drinkers
allow the bird to spill water and add contaminates to the standing water. Continual overflow
watering systems reduce the health risk to the birds but produce a greater quantity of wastewater.
Nipple water delivery systems are placed in the cage and deliver water only when the bird is
sucking on the nipple. Approximately 62 percent of all layer operations use nipple drinker
systems (USDA APHIS, 2000b). However, for layer operations with more than 100,000 birds
this number increases to approximately 81.5 percent (USDA NAHMS, 2000). Watering systems
may also use water pressure sensors and automatic shutoff valves to reduce water spillage. The
sensor will detect a sustained drop in water pressure resulting from a break hi the water line. The
sensor will then stop the water flow to the broken line and an alarm will sound. The operator can
then fix the broken line and restore water to the animals with minimal water spillage. There is
little information about the relative use of water pressure sensors within the layer industry.
4.2.2.7 Waste Disposal
Practices for the disposal of layer wastes are similar to those for other poultry litter. After
removal from the housing facilities, waste can be directly applied to the land (if available), stored
prior to final disposal, or pelletized and bagged for use as commercial fertilizer. Waste storage,
application of litter, and other poultry waste disposal practices are discussed in detail hi Section
4.2.1.6. The percentage of layer and pullet operations with and without enough land for
application of manure on a nitrogen- and phosphorus-basis and operations with no land are
shown hi Tables 4-58 and 4-59. The facilities that have "no land" were determined by running
queries of the USDA 1997 Census of Agriculture data to identify facilities that did not grow any
of the 24 major crops grown hi the U.S.
Table 4-58. Percentage of Layer Dominated Operations With Sufficient, Insufficient, and
No Land for Agronomic Application of Generated Manure
Capacity
(Number of
Birds)
1-29,999
30,000-59,999
60,000-179,999
> 180,000
Total
Sufficient Land
Nitrogen
12.2
6.8
6.2
1.1
10.5
Phosphorus
9.2 ;
1
0
0
6.9
Insufficient Land
Nitrogen
49.1
60.3
52
46.6
49.5
Phosphorus
53
65
62.2
47.1
57.5
No Land
41.1
33.2
36.8
52.9
38.8
Source: USDANASS, 1999c
4-58
-------
Table 4-59. Percentage of PuUet Dominated Operations With Sufficient, Insufficient, and
No Land for Agronomic Application of Generated Manure
Capacity
(Number of
Birds)
1-29,999
30,000-59,999
60,000-179,999
> 180,000
Total
Sufficient Land
Nitrogen
11.6
11.9
14.1
2
11.6
Phosphorus
5.9
1.7
1.1
0
3.7
Insufficient Land
Nitrogen
47.3
54.9
49.2
45.1
49.5
Phosphorus
53
65
62.2
47.1
. 57.5
No Land
41.1
33.2
36.8
52.9
. 38.8
Source: USDANASS, 1999c
Mortality and the disposal of dead hens is a potentially significant source of contamination at
laying operations. A total of 6.5 percent of hens placed in the last completed flock (one flock per
farm site) died by 60 weeks of age and overall the average cumulative mortality was 14.6 percent
(USDA APHIS, 2000b). The common methods of disposing of dead hens and frequency of use
are presented in Table 4-60. Tables 4-61 and 4-62 present this information for operations with
fewer than and more than 100,000 laying hens. Larger facilities are much more likely than
smaller facilities to send dead birds to rendering plants (50.2 percent versus 21.1 percent). While
smaller facilities are more likely than larger facilities to bury their dead birds (45.6 percent versus
9.1 percent).
Table 4-60. Frequency of Disposal Methods for Dead Layers for All Facilities
Method of Disposal
Composting
Incineration
Covered deep pit
Rendering
Other
Total
Farm Sites
Percent
15.0
9.0
32.0
32.0
16.1
—
Std Error
(3.5)
(2.9)
(5.8)
(4.9)
(3.6)
Dead Hens
Percent
11.7
10.4
17.9
41.4
18.6
100.0
Std Error
(4.1)
(4.5)
(4.3)
(8.6)
(5.4)
Source: USDA APHIS, 2000b
4-59
-------
Table 4-61. Frequency of Disposal Methods for Dead Layers
for Facilities With <100,000 Birds
Method of Disposal
Composting
Incineration
Covered deep pit
Rendering
Other
Total'
Farm Sites
Percent
13.9
9.3
45.6
21.1
14.0
-
Std Error
4.7
4.2
7.2
4.5
4.7
-
Dead Hens
Percent
13.4
19.8
36.4
19.7
10.7
100.0
Std Error
7.5
9.8
8.3
6.0
3.8
—
Source: USDANAHMS, 2000
Table 4-62. Frequency of Disposal Methods for Dead Layers
for Facilities With >100,000 Birds
Method of Disposal
Composting
Incineration
Covered deep pit
Rendering
Other
Total
Farm Sites
Percent
16.8
8.7
9.1
50.2
19.7
-
Std Error
4.6
3.3
2.2
7.2
5.8
-
Dead Hens
Percent
10.6
4.6
6.5
54.8
23.5
100.0
Std Error
4.4
2.5
2.5
10.9
8.7
—
Source: USDANAHMS, 2000
E
4.2.3 Turkey Sector
i
This section describes the following aspects of the turkey industry:
i
• 4.2.3.1: Distribution of the turkey industry by size and region
• 4.2.3.2: Production cycles of turkeys ;
• 4.2.3.3: Turkey facility types and management
• 4.2.3.4: Turkey waste management practices
• 4.2.3.5: Pollution reduction '
• 4.2.3.6: Waste disposal !
4-60
-------
National Overview
Turkey production has increased steadily over the past 2 decades, and as hi the other poultry
sectors, there has been a shift hi production to fewer but larger operations. Between 1982 and
1997, almost 21 percent of the turkey operations went out of business (USDA NASS, 1998b).
As shown hi Table 4-63, the number of turkey operations decreased from 12,708 operations hi
1992 to 12,207 operations hi 1997, a 4 percent decrease. The number of turkeys produced rose
approximately 10 percent between 1992 and 1997. The number of hens held for breeding,
however, decreased by almost 6 percent during the same period.
As hi the broiler industry, most turkeys are produced under contract production arrangements.
For each contract arrangement, an integrator company provides the birds, feed, medicines, bird
transport, and technical help. The contract producer provides the production facilities and labor
to grow the birds from hatchlings to market-age birds, hi return, the contract producer receives a
guaranteed price, which may be adjusted up or down based on the performance, of the birds
compared with that of other flocks produced or processed by the company during the same span
of time. Some turkeys are raised by independent turkey producers. Even under this type of
production, however, the independent producer may arrange for feed, poults, medical care, and
possibly processing, through contracts. Finally, some turkeys are produced on farms owned by
the integrator company. The integrator company may also be the company that processes the
birds; however, some turkey integrators provide all services except the processing, which the
integrator arranges with a processing company.
Table 4-63. Turkey Operations (Ops) in 1997,1992,1987, and 1982 With Inventories of
Turkeys for Slaughter and Hens for Breeding
Total Farms
With
Turkeys
Turkeys sold for
slaughter
Turkey hens kept
for breeding
1997
Ops
6,031
5,429
747
Production
307,586,680
299,488,350
8,098,330
1992
Ops
6,257
5,658
793
Production
279,230,136
272,831,801
6,398,335
1987
Ops
7,347
6,813
761
Production
243,336,202
238,176,199
5,160,003
1982
Ops
7,498
6,838
1,040
Production
172,034,935
167,540,306
4,494,629
4.2.3.1 Distribution of 'Turkey Operations by Size and Region .
EPA's 1974 CAFO Effluent Limitations Guidelines and Standards generally apply to turkey
operations with more than 55,000 birds. (See Chapter 2 for the definition of a CAFO, and
Chapter 5 for a discussion of the basis for revisions to the poultry subcategories.) Where
numbers of birds are presented, all birds regardless of age (e.g., poult, laying age, or pullet) or
function (i.e. breeder, layer, meat-type birds) are included unless otherwise indicated hi the text.
4-61
-------
The consolidation of the turkey industry has mirrored that of other livestock industries. The
number of turkey farms with fewer than 30,000| birds decreased from 5,113 in 1987 to only 3,378
in 1997 (USDA NASS, 1999b). Concurrently, the number of operations with more than 60,000
birds increased 26 percent from 1232 in 1987 to 1671 in 1997. Although these changes are not
as dramatic as those for the swine or broiler industry, they are indicative of an industry that is
undergoing a steady transformation into one dominated by large integrated operations.
Table 4-64 presents the number of turkey operations in 1997 by size and region. Table 4-63
presents the average number of birds at these operations, and Table 4-66 presents the distribution
of turkey production by size of operation and re|gion. It is important to note that the 369 largest
operations (2.7 percent) had 43.6 percent of the| total turkey count. These tables reflect the use of
2.5 turns (flocks) per year. USDA NASS performed an analysis for EPA to estimate how
variations hi the estimated of number of turns per year would change the number of potential
CAFOs (operations with more than 55,000 birds). This analysis showed that there would be only
minor changes to the estimated number of CAFOs if the estimated number of turns was adjusted
to two or three turns.
i
State-level data from the 1997 Census of Agriculture (USDA NASS, 1999b) indicate that states
in the Midwest and Mid-Atlantic regions account for more than 70 percent of all turkeys
produced. Key production states (determined by number of turkeys produced) are North
Carolina, Minnesota, Virginia, Arkansas, California, and Missouri. Other states with significant
production include Indiana, South Carolina, Texas, Pennsylvania, and Iowa.
Table 4-64. Number of Turkey Operations in 1997 by Region and Operation Size
Region*
Central
Mid-Atlantic
Midwest
Other
National
1
Number of Turkey Operations by Size
(Operation Size Presented by Number of Birds Spot Capacity)
X)-16,500
2,301
3,265
4,016
2,035
11,617
>16,500-38,50Q
54
597
493
222
1,366
>38,500-55,000
19
143
121
83
366
>55,000
34
83
142
110
369
Total
2,408
4,088
4,772
2,450
13,718
• Central-ID, MT, WY, NV, UT, CO, AZ, MM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY,
TO, NC; Midwest-ND, SD, MN, MI, WI, OH, IN, IL, IA, MO, NE, KS; Othei=WA, OR, CA, AK, HI, AR, LA, MS, AL, GA, SC, FL
Source: USDA NASS, 1999c
4-62
-------
Table 4-65. Average Number of Birds at Turkey Operations in
1997 by Region and Operation Size
Region*
Central
Mid-Atlantic
Midwest
Other
National
Average Turkey Counts by Operation Size
(Operation Size Presented by Number of Birds Spot Capacity)
X)-16,500
311
1,705
1,231
818
1,110
>16,500-38,500
25,420
24,903
24,303
26,310
24,936
>38,500-55,000
47,310
45,193
45,469
45,520
45,486
>55,000
172,416
97,111
158,365
116,295
133,340
All Operations
3,675
8,551
9,413
. 9,827
8,223
•CentraMD, MT, WY, NV, UT, CO, AZ, MM, TX, OK; Mid-Atlantic=ME, NH, VT,NY, MA, RJ, CT, NJ, PA, DE, MD, VA, WV KY
N=, SD, MN, MI, WI, OH, IN, EL, IA, MO, ME, KS; Othei=WA, OR, CA, AK, HL AR, LA, MS, AL, GA?SC, FL '
Table 4-66. Distribution of Turkeys in 1997 by Region and Operation Size
Region"
Central
Mid-Atlantic
Midwest
Other
National
Percentage of Total Turkey Counts by Operation Size
(Operation Size Presented by Number of Birds Spot Capacity)
X)-16,500
0.64
4.93
4.38
1.48
11.43
>16,500-38,500
1.22
13.18
10.62
5.18
30.20
>38,500-55,000
0.80
5.73
4.88
3.35
14.75
>5S,000
5.20
7.15
19.94
11.34
43.62
Total
7.85
30.99
39.82
21.34
100.00
•CentraHDD, MT, WY, NV, UT, CO, AZ, NM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE MD VA, WV KY
So^U^ANA^l SD'MN> ^ ^ OH> ^ ^ ^ M0> ^ KS; 0ther=WA> OR, CA, AK, HL AR, LA, MS,'AL, GA/SC, EL '
4.2.3.2 Production Cycles of Turkeys
The growth of a turkey is commonly divided into two phases: brooding and grow out. The
brooding phase is the period of the poult's life extending from 1 day to about 6-8 weeks. During
this time, the poults are unable to maintain a constant body temperature and need supplemental
heat. Brooder stoves are used to keep the ambient temperature at 90 to 95 °F when the poults
arrive; thereafter, the producer decreases the temperature by 5 °F for the next 3 weeks until the
temperature reaches 75 °F. Poults are extremely susceptible to disease and are typically
administered special starter feeds containing antibiotics and a high percentage of protein. A
difference between turkeys and broilers is that feeding strategies such as the use of phytase to
4-63
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reduce phosphorus content in waste is not employed with turkeys through the entire life cycle
because phytase is thought be some to inhibit bone development in poults. As with the broiler
industry, further research in diet, nutrition, and the complex relationships between calcium,
vitamins, and phosphorus may overcome this limitation.
i
The grow-out phase is the period in a turkey's [life between the brooding phase and the market or
breeding phase. Depending on the sex of the birds> the grow-out phase typically lasts up to-14
weeks. Modern turkeys grow rapidly. A torn (male turkey) poult weighs about 1A pound at birth;
at 22 weeks it weighs almost 37 pounds. Hens (female turkey) are usually grown for 14 to 16
weeks and toms from 17 to 21 weeks before being marketed. Most operators start fewer toms
than hens in a given house to allow more space for the larger birds.
i
4.23.3 Turkey Facility Types and Management
Market and breeder turkeys are raised in similar housing systems. Typically, young turkey poults
are delivered to the operation on the day of or the day after hatching. The poults are placed hi
bams called brooder houses. The brooder houses for turkeys are usually as wide as broiler and
pullet houses but are usually only 300 to 400 feet long. The houses have an impermeable floor
surface made of either clay or cement. The floors are then covered with 3 to 4 niches of bedding.
'!
As with broilers, ventilation is usually provided by a negative-pressure system, with exhaust fans.
drawing air out of the house and fresh air returning through ventilation ducts around the
perimeter of the roof. Some turkey houses have side curtains that can be retracted to allow
diffusion of air. More advanced ventilation systems use exhaust fans controlled by a thermostat
and timer. Brooding heaters are normally present in one-third to one-half of the house, for the
early stages of development. As the poults get older, they are usually released into the other two-
thirds or half of the house and remain there until they are of market age. In some operations the
poults are moved to a specially designed grower house, where they stay until they are of market
age. Some operations will move poults to range.
The construction of the housing facilities varies by region and depends on climatic conditions
and production practices. Generally, hi the southern and southeastern U.S. the houses are more
open. The side walls of the houses are 6 to 8 feet high, with a 4- to 5- foot-wide opening
covered by wires and curtains. Since moderate winters are normal in the South and Southeast,
the curtains can contain the heat necessary to maintain a reasonable temperature within the
commercial poultry houses. In the northern and central states, most houses have solid side walls
and contain considerable insulation to combat the colder temperatures. These houses rely on
exhaust fans or moveable solid side walls during the hot summer days to dimmish the effects of
heat stress on the birds. ;
These traditional systems are called two-age farms because two ages of birds can be on the farm
at one time. Once the poults have been moved to the grower bam, the brooder house is totally
cleaned out for another group of poults. This [cleanup includes removal of all litter used during
the brooding phase. The second group of poults occupies the brooder house while the first group
of birds is still in the grower bam. Operations hi the Shenandoah Valley area of Virginia and
t'4-64
-------
West Virginia are known to use a modification of the typical two-age management system.
Under this system the houses are longer. Poults may occupy one end of the house, while an older
group is being grown out at the other end. The birds do not have to be moved as often under this
system.
The two-age farm system has served the turkey industry for more than 20 years. Currently,
however, there are efforts to modify this system because of morbidity and mortality. The '
modifications are directed at raising older birds in facilities removed from the poults. This
approach provides an opportunity to break any disease cycle that might put the birds, especially
the younger ones, at increased risk for disease (USEPA, 1998),
4.2.3.4 Turkey Waste Management Practices
For brooder facilities, the litter is removed after every flock of brooded poults. This practice is
necessary to provide the next group of poults with clean bedding to achieve the lowest possible
risk of disease exposure. Poult litter many be composted between flocks to control pathogens
and then reused in the grow out houses. For grower systems, the litter is removed once a year. In
between flocks, cake is removed and the old litter may be top-dressed with a thin layer of new
bedding. For single-age farms, the bedding in the brooding section is moved to the grower
section. New bedding is put in the brooder section, and the facilities are prepared for the next
group of poults.
4.2.3.5 Pollution Reduction
New technologies in drinking water systems result in less spillage and ensure that turkey litter
stays drier. Feeding strategies will also reduce the quantity of waste generated by ensuring that
turkeys do not receive more feed than required for optimal growth. State regulations have also
driven many turkey operations to handle mortalities in ways other than burial such as rendering
and composting, which are on the rise (see Section 4.2.3.6).
Nipple water delivery systems reduce the amount of wasted water and are healthier for the
animals. Trough or bell type watering devices allow the animal to spill water and add
contaminants to the standing water. Nipple water systems deliver water only when the animal is
sucking on the nipple. Watering systems may also use water pressure sensors and automatic
shutoff valves to reduce water spillage. The sensor will detect a sustained drop in water pressure
resulting from a break in the water line. The sensor will then stop the water flow to the broken
line and an alarm will sound. The operator can then fix the broken line and restore Water to the
animals with minimal water spillage.
Feeding strategies can be used to reduce the quantity of nutrients in the excreta. Dietary
strategies designed to reduce nitrogen and phosphorus include enhancing the digestibility of feed
ingredients, genetic enhancement of cereal grams and other ingredients resulting in increased
feed digestibility, more precise diet formulation, and improved quality control. Although
nitrogen and phosphorus are currently the focus of attention, these strategies also have the
potential to decrease other nutrients. There is debate on the impacts of phytase feed supplements
4-65'
-------
for turkey poults concerning bone growth and bone development. Phytase additions are expected
to achieve a reduction in phosphorus excretion of 20 to 60 percent depending on the phosphorus
form and concentration in the diet (NCSU, 1999b). Protein content, calcium, other mineral
content, vitamin B, as well as other factors identified in the literature influence .the effectiveness
of phytase use in feed. Additional information pn feeding strategies for turkeys can be found in
Chapter 8. i
i
i
4.23.6 Waste Disposal \
\
Practices for the disposal of turkey litter are similar to those for other poultry litter. After
removal from the housing facilities, waste can be directly applied to the land (if available), stored
prior to final disposal, or pelletized and baggedjfor use as commercial fertilizer. Waste storage,
application of litter, and other poultry waste management practices are discussed in detail in.
Section 4.2.1.4. The percentage of turkey operations with and without enough land for
application of manure on a nitrogen- and phosphorus-basis and operations with no land are
shown in Table 4-67. The facilities that have nb land were determined by running queries of the
USDA 1997 Census of Agriculture data to identify facilities that did not grow any of the 24
major crops grown in the U.S. '
i
Table 4-67. Percentage of Turkey Dominated Operations With Sufficient, Insufficient and
No Land for Agronomic Application of Generated Manure
Capacity
(Number of
Birds)
1-16,499
16,500-38,499
38,500-54,999
> 55,000
Total
Sufficient Land:
Nitrogen
15.6
6.8
4.1
3
9.4
s
Phosphorus
5.9 ;
0.3
1
0
0 :
2.4 i'
Insufficient Land:
Nitrogen
52.5
65.4
65.5
58.1
59.5
Phosphorus
62.2
71.9
69.9
61.1
66.5
No Land
31.8
27.9
30.4
38.9
31.1
Source: USDA NASS, 1999c
Disposal of dead birds can be handled through |composting, incineration, burial in deep pits,
rendering, and disposal in landfills. Technical information on practices for the disposal of dead
animals is presented in Chapter 8; however, there is little information available on the relative
use of these practices within the turkey industry.
43 Dairy Industry >
Dairy animal feeding operations include facilities that confine dairy cattle for feeding or
maintenance for at least 45 days in any 12-month period, and do not have significant vegetation
in the area of confinement. Dairies may also perform other animal and agricultural operations
4-66
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that are not covered by the existing dairy effluent guidelines, including grazing, milk processing,
and crop farming.
This section discusses the following about dairy operations:
• Section 4.3.1: The distribution of dairy operations by size of operation and region in 1997
• Section 4.3.2: Dairy production cycles
• Section 4.3.3: Stand-alone heifer raising operations
• Section 4.3.4: Dairy facility management practices
• ' Section 4.3.5: Dairy waste management practices
• Section 4.3.6 lists the references used, in this section
4.3.1 Distribution of Dairy Operations by Size and Region
Current effluent limitations guidelines and standards apply to dairy operations with a capacity of
700 or more mature dairy cattle (both lactating and dry cows), where the animals are fed at the
place of confinement and crop or forage growth or production is not sustained in the confinement
area.
Information presented in this section comes from USDA's National Agricultural Statistics
Service (NASS), 1997 Census of Agriculture data, and from site visits and trade associations.
The 1993 to 1997 NASS reports on dairy operations present the number of dairies by size class;
however, dairy operations with more than 200 mature dairy cattle are grouped in one size class;
therefore, an analysis of dairy operations that fall under the current effluent guidelines regulations
(i.e., those with more than 700 milking cows) cannot be completed with NASS data alone. Data
from the 1997 Census of Agriculture provide some additional information on medium and large
(more than 200 milking cows) dairy operations. Although the NASS and Census data do not
match exactly, EPA has found that there is generally a good correlation between the two data
sets. EPA used the Census data to estimate farm counts.
From 1988 to 1997, the number of dairies and milking cows in the U.S. decreased while total
milk production increased. Improved feeding, animal health, and dairy management practices
have allowed the dairy industry to continue to produce more milk year with fewer milking cattle.
Since 1988, the total number of milking cows has decreased by 10 percent and the total number
of dairy operations has decreased by 43 percent, indicating a general trend toward consolidation
(USDANASS, 1995b; 1999d).
Between 1993 and 1997, the number of operations with fewer than 200 milking cows decreased,
while the number of operations with 200 milking cows or more increased. Both NASS and the
1997 Census of Agriculture have collected data that quantify the changes by size class. Based on
the NASS data, the number of operations with 200 milking cows or more increased by almost 7
percent between 1993 and 1997, while all smaller size classes decreased in numbers of
operations. Table 4-68 shows the estimated distribution of dairy operations by size and region in
1997, and Table 4-69 shows the total number of milk cows and average cow herd size by size
class in 1997. EPA derived the data in these tables from the Census data (ERG, 2000b).
4-67
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According to Census of Agriculture data, of the 116,874 dairy operations across all size groups in
1997, Wisconsin had the most with 22,576 (19 percent), followed by Pennsylvania with 10,920
(9 percent), Minnesota with 9,603 (8 percent), and New York with 8,732 (7 percent). Table 4-70
presents the number of dairies by top-producing states for the following size groups:
• 1 to 199 milk cows;
• 200 to 349 milk cows; >
• 350 to 700 milk cows; and
• more than 700 milk cows.
Of the large dairies (more than 700 milking cows), California has the most operations (46
percent), and of the medium dairies (200 to 700 milking cows), California, New York,
Wisconsin, and Texas have the most operations.
Table 4-71 shows the annual milk production in 1997 for the top-producing states. Although
California has only 2,650 dairy farms in all, it is the largest milk-producing state in the U.S.,
according to NASS data and data received from the National Milk Producers Federation
(National Milk Producers, 1999; USDA NASS, 1999d).
Table 4-68. Distribution of Dairy Operations by Region and Operation Size in 1997
Region"
Central
Mid-Atlantic
Midwest ,
Pacific
South
National
1 Number of Operations
0-199 Milk
Cows
9,685
32,490
59,685
2,875 •
5,001
109,736
200-349
Milk Cows
593
870
943
722
253
3,381
350-700
Milk Cows
433
487
497
725
170
2,312
>7QQM3k
Cows
404
81
90
786
84
1,44.5
Total
11,115
33,928
61,215
5,108
5,508
116,874
1 Central-ID, MT, WY, NV, UT, CO, AZ, NM, TX, OK; Mid-Aflantip=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY, TN,
NC; Midwest=ND, SD, MN, Ml, WJ, OH, IN, It, IA, MO, ME, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC, FL
k-68
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Table 4-69. Total Milk Cows by Size of Operation in 1997
Size Class
0-199 Milk Cows
200-349 Milk Cows
350-700 Milk Cows
> 700 Milk Cows
Total United States
Number of
Operations
109,736
3,381"
2,312'*
l,445b
116,874
Total Number of Milk
Cows
5,186,000
795,000
1,064,000
2,050,455
9,095,455
Average Milk Cow
Herd Size
47
235
460
1,419
78
• Estimated value. Published Census of Agriculture data show 4,881 dairies with 200-499 milk cows. Assumes approximately 70 percent have
200-349 milk cows and 30 percent have 350-500 mine cows. •
b Estimated value. Published Census of Agriculture data show 1,379 dairies with 500-999 milk cows. Assumes approximately 60 percent have
500-699 milk cows and the remainder have 700-1,000 milk cows.
Table 4-70. Number of Dairies by Size and State in 1997
Location
California
Florida
Idaho
Michigan
Minnesota
New York
Pennsylvania
Texas
Washington
Wisconsin
Total United States
Size Class
1-199 Milk
Cows
969
495
1,105
3,743
9,379
8,162
10,693
3,562
925
22,041
109,736
200-349
Milk Cows
471
51
119
144
135
319
148
266
175
333
3,381
350-700 Milk
Cows
'547
58
90
81
75
194
71
188
130
171
2,312
>700Milk
Cows
663
62
90
22
14
57
8
97
72
31
1,445
Total
2,650
666
1,404
3,990
9,603
8,732
10,920
4,113
1,302
22,57.6
116,874
4-69
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Table Table 4-71. Milk Production by State in 1997
Location
California
Florida
Idaho
Michigan
Minnesota
New York
Pennsylvania
Texas
Washington
Wisconsin
Total United States
Total Milk Production
(million pounds)
27,582
2,476
5,193
5,410
9,210
11,530
10,662
5,768
5,305
22,368
156,091
Milk Produced Per Cow (pounds)
19,829
15,475
,19,092
17,680
16,186
16,495
16,951
15,259
20,968
16,057
16,871
43.2 Dairy Production Cycles
The primary function of a dairy is the production of milk, which requires a herd of mature dairy
cows that are lactating. In order to produce milk, the cows must be bred and give birth.
Therefore, a dairy operation may have several types of animal groups present, including:
• Calves (0 to 5 months)
• Heifers (6 to 24 months)
• Cows that are close to calving (close-up cows)
• Lactating dairy cows
• Dry cows
• Bulls
Most dairies operate by physically separating and handling their animals in groups according to
age, size, milking status, or special management needs. This separation allows each group to be
treated according to its needs. Section 4.3.2.1 presents a description of the typical mature dairy
herd, and Section 4.3.2.2 discusses the immature animal groups that may also be present at the
dairy.
433.1 Milk Herd '
The dairy milk herd is made up of mature dairy cows that have calved at least once. These
mature cows are either lactating or "dry" (not currently producing milk). After a cow has calved,
the milk she initially produces (called "colostrum") contains higher amounts of protein, fat,
minerals, and vitamins than normal milk. The colostrum is usually collected and fed to the
calves. After about 4 days, the milk returns to normal and the cow rejoins the lactating cow herd.
4-70
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After being milked for about 10 to 12 months after calving, the cows go through a dry period.
These dry periods allow the cow to regain body condition and the milk secretory tissue in the
udder to regenerate. The dairy industry has reported an average of 60.5 days of dry period per
cow (USDA APHIS, 1996a).
Periodically, all dairies must cull certain cows that are no longer producing enough milk for that
dairy. Cows are most often culled for the following reasons: reproductive problems; udder or
mastitis problems; poor production for other reasons; lameness or injury; disease; or
aggressiveness or belligerence. In 1995, an average of 24 percent of the herd was culled from all
size operations (USDA APHIS, 19?6a). Dairies in high milk-producing regions (e.g., California)
have reported during site visits cull rates of up to 40 percent.
Some dairies decide when a cow is to be culled by determining a milk break-even level (pounds
of milk per cow per day). Approximately 28 percent of dairies use this practice and reported an
average milk break-even level of approximately 33 pounds per cow per day. The milk break-
even levels ranged from 32.5 pounds per cow per day at small dairies (less than 100 head) up to
36.5 pounds per cow per day at larger dairies (200 or more head) (USDA APHIS, 1996a).
Nearly all culled cows (approximately 96 percent) are sent away for slaughter. Approximately 74
percent are sent to a market, auction, or the stockyards. Others (21 percent) are sold directly to a
packer or slaughter plant, and the remaining 1 percent are sent elsewhere. Cows that are not sold
for slaughter (approximately 4 percent) are usually sent to another dairy operation (USDA
APHIS, 1996a).
4.3.2.2 Calves, Heifers, andBulls
The immature animals at a dairy are heifers and calves. Typically, according to Census of
Agriculture data, for dairies greater than 200 milking cows, the number of calves and heifers on
site equals approximately 60 percent of the mature dairy (milking) cows. EPA assumes that there
are an equal number of calves and heifers on site (30 percent each). Calves are considered to be
heifers between the age of six months and the time of their first calving (between 25 and 28
months of age) (USDA APHIS, 1996a). Heifers tend to be handled in larger groups, and often
they are divided for management purposes into a breeding group and a bred heifer group (Bickert
etal., 1997). Heifers and cows are often bred artificially. They may be placed daily in
stanchions for estrus (heat) detection with the aid of tail chalk or heatmount detectors. Heifers
and cows in pastures or in pens without stanchions may be heat detected by observation and then
bred in a restraining chute. Heifers that do not conceive after attempts with artificial
insemination are often placed in groups with a breeding-age bull to allow natural service of those
animals. Approximately 45 percent of dairy operations do not keep bulls on site, and
approximately 35 percent of dairy operations keep one bull on site for breeding (USDA APHIS,
1996a).
Cows and heifers that are at the end of their pregnancy are considered to be "periparturient" or
"close-up cows." About 2 weeks before she is due, the heifer or cow is moved from her regular
herd into a smaller pen or area where she can be observed and managed more closely. When the
4-71
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cow is very near to calving, she is often moved to an isolated maternity pen. Shortly after birth,
the calves are separated from their mothers and are generally kept isolated from other calves or in
small groups until they are about 2 months old. After the calves are weaned from milk (at about
3 months of age), they are usually.moved from'their individual pen or small group into larger
groups of calves of similar age. Female calves; are raised (as replacements) to be dairy cows at
the dairy or sent to an off-site calf operation. Female Calves (heifers) may also be raised as beef
cattle. Male calves that are not used for breeding are either raised as beef cattle (see Section 4.4)
or as veal calves (see Section 4.4.5).
4.3.3 Stand-Alone Heifer Raising Operations
i
Stand-alone heifer raising operations provide replacement heifer services to dairies. It has been
estimated that 10 percent to 15 percent of all dairy heifers are raised by stand-alone heifer raisers
(Personal communication: Larry Jordan and Dr. Don Gardner). These heifer raising operations
often contract with specific dairies to raise those dairies' heifers for a specified period of time,
and many also provide replacement heifers to any dairy needing additional cows. The age at
which dairies send their animals to heifer raising operations varies significantly (USDA APHIS,
1996a). Table 4-72 shows the percentage of dairies that use heifer raising operations, the median
age at which heifers are received by these facilities, and the amount of time that the heifers
remain at these facilities. ;
Table 4-72. Characteristics of Heifer Raising Operations
Age of Heifer
0-4 months
4 months - breeding
Breeding - first calving
Percentage of Dairies '
Using Heifer Raisers |
41.2 !
47.1
11.8 :
Median Age of Heifer
1 week
6 months
Breeding age
Time That Heifers
Remain on Site
12 months
15 months
9 months
There are a number of advantages for dairies to use heifer raising operations.. Specifically,
dairies using heifer raising operations could expand then- herd size by 25 percent or more within
existing facilities, specialize hi milking cows or raising crops, and obtain healthier and better
producing milking cows. In addition, raising calves off the farm may reduce risks of
transmission of diseases for which older cows are the main source of infection. Some
disadvantages include an increased risk of introducing disease into the herd and a shortage of
replacement heifers if the raiser's breeding results are less than adequate. Also, the costs
associated with raising the heifers could run higher than what the dairies are paying if labor, feed,
and other resources are not allocated profitably! (USDA APHIS, 1993).
Custom raising of dairy heifers is becoming more common as dairy herds increase in size and
dairy farmers do not have facilities to raise all their heifers (Noyes, 1999). Throughout the U.S.,
the level of specialization is increasing for dairy farms; in fact, some large dairy farms raise no
crops, purchase all of their feedstuffs, or do not raise replacement heifers for the milking herd.
4-72
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Herd owners for these dairies must use other strategies to obtain herd replacements. As a result,
enterprises that specialize in raising dairy calves and heifers are found in many western U.S.
states (Faust, 2000). It is also believed that the poor beef market in the last few years has caused
some beef feedldts to add pens of dairy heifers or switch to heifers entirely (Personal
Communication: Dr. Roger Cady).
Stand-alone heifer operations use two primary methods for raising their animals. One method is
to raise heifers on pasture, usually in moderate to warm climates where grazing land is available.
The second method is to raise heifers in confinement (on drylots, as for beef cattle).
Confinement is commonly used at operations in colder climates or areas without sufficient
grazing land (Personal Communication: Larry Jordan).
The actual number of stand-alone heifer raising operations, as well as the number of confined
operations, is unknown. However, based on information supplied by industry representatives
(e.g., Professional Dairy Heifer Growers Association), EPA estimates that there may be 5,000
heifer raising operations in the U.S.: 300 to 400 operations with more than 1,000 head; 750 to
1,000 operations with more than 500 head; and 4,000 heifer operations with fewer than 500 head
(most of them with around 50 head) (Personal Communication: Dr. Roger Cady). Most large
dairy heifer raising operations (those with more than 1,000 head) are confinement-based while
smaller operations are often pasture-based (Personal Communication: Dr. Roger Cady). Table 4-
73 shows EPA's estimate of confined heifer raising operations by size and region (ERG 2000a-
2000b).
Table 4-73. Distribution of Confined Heifer Raising Operations by Size and Region in 1997
Region"
Central
Mid-Atlantic
Midwest
Pacific
South
National
Number of Operations
300-499
Heifers
25
0
200
25
0
250
500-1,000
Heifers
250
0
100
150-
0
500
> 1,000
Heifers
180
0
0
120
0
300
Total
455
0
300
295 '
. 0
1,050
,-_-,VT,NY,MA,RLCT,NJ,PA,DE,MD,VA,WV,KY,TN,
NC; Midwest=ND, SD, MN, ML WI, OH, IN, IL, IA, MO, ME, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC, FL
The sizes of heifer raising operations range from 50 head (typical "mom and pop" operations) to
25,000 head and tend to vary geographically. The average size of a heifer operation located west
of the Mississippi River is 1,000 to 5,000 head, while the average size in the upper Midwest,
Northeast, and South is 50 to 200 head. Nationally, the median size of a dairy heifer raising
operation is approximately 200 head (Personal Communication: Dr: Roger Cady).
Stand-alone heifer raising operations are found nationwide with more heifer raisers located where
cows are concentrated and in areas where the dairy industry is evolving toward more
4-73
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specialization (Bocher, 2000). EPA estimates lhat, of the number of heifers raised at stand-alone
heifer operations, approximately 70 percent are managed in the West, 20 percent are managed in
the South/Southeast, 7 percent are managed hi the Northeast, and approximately 3 percent are
managed in the upper Midwest. The upper Midwest is alsp believed to be the single largest
growing region with respect to small heifer operations (Personal Communication: Dr. Roger
Cady).
4.3.4 Dairy Facility Management
This section describes factors that affect the facility management of a dairy operation, including
housing by type of animal, as well as use of housing in the industry, flooring and bedding type,
feeding and watering practices, milking operations, and rotational grazing.
4.3.4.1 Housing Practices \
The purpose of dairy housing is to provide the animals with a dry and comfortable shelter, while
providing the workers with a safe and efficient working environment. Optimal housing facilities
accommodate flexibility hi management styles and routines, enhance the quality of milk
production, and allow for the protection of the environment, yet remain cost-effective (Adams,
1995). The following subsections describes housing for each type of animal group according to
age, from milking cows to calves.
Milking Cows
The primary goal in housing lactating dairy cojws is to provide an optimum environment for the
comfort, proper nutrition, and health of the lactating cow for maximum milk productivity. It is
also designed to allow for efficient milking processes. The most common'types of lactating cow
housing include freestalls, drylots, tie stalls/stanchions, pastures, and combinations of these. The
types of housing used for dry cows include loose housing and freestalls (Stull et al., 1998). These
housing types are described in detail below. [
• Freestalls - This type of housing provides individual resting areas for cows in freestalls or
cubicles, which helps to orient the cow for! manure handling. Freestalls provide the cows
with a dry and comfortable place to rest ancl feed. The cows are not restrained in the
freestalls and are allowed to roam on concrete alleys to feeding and watering areas. Manure
collects in the travel alleys and is typicallyremoved with a tractor or mechanical alley-
scraper, by flushing with water, or through slotted openings in the floor (refer to Section 4.3.5
for a more detailed description of waste haindlirig) (Adams, 1995). Recently, there has been a
trend toward using freestalls to house dairy cows and many loose housing units have been
converted to freestalls (Bickert, 1997).
• Drvlots - Drylots are outside pens that allop the animals some exercise, but do not generally
allow them to graze. The use of drylots depends upon the farm layout, availability of land,
and weather conditions. Also, milking cows are not likely to spend their entire time on a
drylot, as they need to be milked at least twice a day at a tiestall or in a milking parlor.
,4-74
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• Tie Stalls/Stanchions - Tie stalls or stanchions confine the cow to a single stall where she
rests, feeds, and is often milked. The tie stall prevents the cow from moving out of her stall
with a chained collar, but allows her enough freedom to get up and lie down without
interfering with her neighbors. Tie stalls are also designed to allow the cows access to feed
and fresh water in a natural grazing position (Adams, 1995). Cows that are housed in tie stalls
may be let out at certain times each day (e.g., between milkings) to graze in a pasture. Tie
stalls are the most predominant type of dairy cow housing for lactating cows (USDA APHIS,
1996a); however, this is true of older, smaller dairies. The current preference, particularly for
medium and large dairies, is freestalls.
• LooseHousing - Barns, shades, and corrals are considered loose housing. The design of these
facilities depends upon the number of cows, climate, and waste-handling techniques.
Overcrowding in this type of housing can lead to health problems and may reduce access to
feed, water, or resting areas for some subordinate animals. Loose housing that is hard-
surfaced typically has at least a 4 percent slope, depending on soil type and rainfall (Stull et
al, 1998).
* Pastures - Depending on the farm layout, availability of pastureland, and weather conditions,
heifers or cows may spend part or most of their day in a pasture. Milking cows do not spend
all of their day outside, since they are milked at least twice per day in a parlor or from a tie
stall. On some farms, the cows may be contained outdoors during the day, but are housed in a
tie stall or freestall overnight.
Close-Up Cows
The primary objective in housing for cows that are close to calving is to minimize disease and
stress to both the cow and calf. Sod pastures are often used in warmer climates or during the
summer; however, the pastures can become too muddy in the winter in some climates, requiring
additional worker time to keep watch over the cows. Alternatively, the cows may be housed in
multiple-animal or individual pens prior to calving. About 2 weeks before the cow is due (i.e., 2
weeks prior to freshening), she is moved to a "close-up" pen. The cow density in close-up pens
is about one-half the density in lactating cow pens to allow the calving cows some space to
segregate themselves from other cows if they go into labor, although calving in close-up pens is
usually avoided.
When birth is very near, cows are moved to a maternity area for calving. If the climate is
sufficiently mild, pastures can be used for a maternity area; otherwise, small individual pens are
used. Pens are usually designed to allow at least 100 square feet per cow and to provide a well-
ventilated area that is not drafty (Stull et al., 1998).
Approximately 45 percent of all dairy farms have maternity housing apart from the housing used
for the lactating cows. This -feature is more prevalent in larger farms than in smaller farms.
Approximately 87 percent of farms with 200 or more cows have separate maternity housing
(USDA APHIS, 1996a). .
4-75
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Bulls
When bulls are housed'on site at a dairy operation, they are typically kept in a pen or on pasture.
If possible, bulls are penned individually with sufficient space for special care and to reduce
fighting. When a bull is grazed on pasture, an electric fence is typically used to prevent the bull
from escaping and causing danger (Bodman et
Heifers
al., 1987).
According to information collected during site! visits, the majority of heifers are kept on drylots
either on or off site. Heifers may also be kept in a pasture, in which the herd is allowed to move
about freely and to graze. Pastures may be projvided with an appropriate shelter. Heifer housing
is typically designed for ease in: \
• Animal handling for treatment (e.g., vaccinations, dehorning, pregnancy checks)
• Animal breeding - |
• Animal observation ;
• Convenient feeding, bedding, and manure handling (Bickert et al., 1997)
Weaned Calves (Transition Housing)
After calves are weaned, they are usually moved from individual pens or small group pens into
housing for a larger numbers of calves. This change causes a number of stresses due to the new
social interactions with other calves, competition for feed and water,, and the new housing.
Therefore, the housing is designed such that the workers can monitor each calf s adjustment into
the social group. Transition housing is used for calves from weaning to about 5 months of age.
The most common types of housing used for weaned calves are calf shelters or superhutches,
transition barns, and calf barns (Bickert et al., 1997).. These types of housing are described
below. i
Superhutches - Superhutches are open-front, portable pens that provide a feeder, water
trough, and shelter for 5 to 12 calves. Superhutches typically provide 25 to 30 square feet per
calf and can be moved in a field, drylot, or pasture as needed to provide calves with a clean
surface. |
Transition Bams - A transition bam is composed of a series of pens for groups of six to eight
calves of up to 6 months old. Some transition barns are designed such that the back and end
walls may be open or covered, depending on the weather conditions.
Calf Barns - A calf barn combines both individual calf pens and transition barns within one
building. The pens can be designed to be easily dismantled for waste removal, to minimize
calf contact, or to provide draft protection (Bickert et al., 1997).
14-76
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Calves
Sickness and mortality rates are highest among calves under 2 months of age; therefore, the
housing for this group typically minimizes environmental stress by protecting the calves against
heat, wind, and rain. Common calf housing types include individual animal pens and hutches,
which are described below.
• Individual Pens - Pens are sized to house animals individually and separate them from others.
Individual pens make it easier to observe changes in behavior, feed consumption, and waste
production, which can indicate sickness. Calves may be raised in 2-foot by 4-foot expanded
metal or slatted wood, elevated pens; however, these pens provide little shelter from drafts
and cold in the winter (Stull, et al., 1998). Individual pens can be used inside a barn to
provide isolation for each calf. Pens are typically 4-feet by 7-feet and removable. Solid
partitions between pens and beyond the front of the pen prevent nose-to-nose contact
between the calves. A cover over the back half of the pen gives the calf additional protection,
especially in drafty locations. Pens can be placed on a crushed rock base or a concrete floor
to provide a base for bedding (Bickert et al., 1997).
• Hutches - Hutches are portable shelters typically made of wood, fiberglass, or polyethylene
and are placed in outdoor areas. Hutches allow for complete separation of unweaned calves
since one calf occupies each hutch. One end of the hutch is open and a wire fence may be
provided around the hutch to allow the calf to move outside. Lightweight construction
materials improve hutch mobility and also allow for easier cleaning. Hutches are typically 4
feet by 8 feet by 4 feet and may be placed inside a shed or structure to provide protection
from cold weather and direct sunlight (Bickert et al., 1997).
Use of Housing in Industry
Table 4-74 summarizes the relative percentages of U.S. dairies reporting various types of housing
for their animals (USDA APHIS, 1996a). These data were collected in 1996 for activities in
1995 by USDA's NAHMS. Note that some operations may have reported more than one type of
housing being used for a particular group. The NAHMS data did not include housing type for
dry cows. It is expected that dry cows are typically housed similarly to lactating cows (Stull et
al., 1998).
Multiple age groups may be housed within a single building that allows for each group to be
managed separately. Larger farms-tend to place their animals in more than one building (Bickert
et al., 1997). Superhutches, transition barns, calf barns, and loose housing were not specifically
addressed hi the NAHMS study, but maybe considered specific types of multiple animal pens.
Dairies predominantly use some sort of multiple animal area for unweaned calves, weaned
calves, and heifers.
4-77
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Table 4-74. Percentage of U.S. Dairies by Housing Type and Animal Group in 1995
Housing Type
Drylot
Freestall
Hutch
Individual animal area
Multiple animal area
Pasture
Tie stall/stanchion
Unweaned
Calves
9.1
2.5
32.5
29.7
40.0
7.4
10.5
Weaned Calves
and Heifers
38.1
9.7
i- NA
6.6
73.9
51.4
11.5
Lactating
Cows
47.2
24.4
NA
2.3
17.9
59.6
61.4
Periparturient
Cows
28.9
5.6
NA
38.3
26.3
41.9
26.3
NA-Not applicable. " [
i
i
43.4.2 Flooring and Bedding j
i
The flooring and bedding used in housing provide physical comfort for the cow, as well as a
clean, dry surface to reduce the incidence of m|astitis and other diseases. Tables 4-75 and 4-76
summarize the various types of flooring and bedding, respectively, that are used for lactating
cows, as reported by U.S. dairies in the NABOBS study (USDA APHIS, 1996b).'
The most predominantly used flooring is smooth concrete, reported by over 40 percent of the
dairies. Other fairly common flooring types include grooved and textured concrete. The less
common flooring types that were reported include slatted concrete, dirt, and pastures (USDA
APHIS, 1996b). The flooring design is important in loose housing to maintain secure footing for
the animals, as well as facilitate waste removal- The surfaces typically contain scarified concrete
areas around water troughs, feed bunks, and entrances. Both hard-surface and dirt lots are sloped
to allow proper drainage of waste and rainfall (Stull et al., 1998).
Table 4-75. Types of Flooring for Lactating Cows
Type of Flooring
Smooth concrete
Grooved concrete
Textured concrete
Pasture
Dirt
Other
Slatted concrete
Percentage of Dairies Reporting
41.6
i 27.2
16.2
1
i , • 6.9
! 5.8
! 1.5
0.8
14-78
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Table 4-76. Types of Bedding for Lactating Cows
—
Percentage of Dairies Reporting
Type of Bedding
Straw and/or hay
Wood products
————
Rubber mats
Corn cobs or stalks
•^H^M
Sand
1
Shredded newspaper
Mattresses
Other
•
Composted manure
Rubber tires
wood products and rubber ma
mattresses, shredded newspaper
percent of the dairies) (u
H *%* C0mm°n bed^ indnd«
™ *f "^ tires' comP°^d manure,
W9fflT ^ ^ repOrted by less ^ 13
4.3.4.3 Feeding and Watering Practices
. Dairies with
T"amilS' md milerals (HRC,
-aised on the farm. (v ilfof a
least 3 months i
(e'g"
(le« ftan 200 cows) i
of cows, a, which only one cow drinks
«nd
cows for at
4-79
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X* al., 1998).
Cows withta .0 ,o 16 days of calving are «£"*£",££,
few pounds of a grata concentrate mix m add-on to forages ™P^ u h is typicd of
feed intake.
innnunoglobulms) ,, ,
etal., 1998). • i
weanh.gtime,usuaUywlientheyare2to3inonthsold(Stunetal, 1!W»J.
typically avaUable to them at all times. ,
i
4.3.4.4 Milking Operations |
holding area, milk room, and treatment area (Bxckert, 1997).
the workers convenient access to the cows' udders.
4-80
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and into the pipeline by a common vacuum pump. The pipeline is usually constructed of glass or
steel and flows into a milk receiver. From the receiver, the milk is pumped through a filter and
into a bulk tank where it is stored until collection.
The milking parlor is typically cleaned several times each day to remove manure and dirt. Large
dairies tend to use automatic flush systems, while smaller dairies simply hose down the area.
Water use can vary from 1 to 3 gallons per day per cow milked (for scrape systems) to 30 to 50
gallons per day per cow milked (for flush systems) in the dairy parlor and holding area (Loudon
etal.,^1985).
Milking at Tie Stalls - Cows that are kept in tie stalls may be milked from their stalls. The
housing is equipped with a pipeline system that flows around the barn and contains ports where
the milking claws may be "plugged in" at each stall. The workers carry the necessary udder and
teat cleaning equipment as well as the milking claws from one cow to the next.
Approximately 70 percent of dairy operations reported that they milk the cows from their tie
stalls, while only 29 percent reported that they used a milking parlor; however, more than half of
the lactating cow population (approximately 55 percent) is milked hi a milking parlor (USDA
APHIS, 1996a; 1996b). Therefore, it can be interpreted that many of the large dairies are using
milking parlors, while the smaller dairies are typically using tie stalls.
Holding Area - The holding area confines cows that are ready for milking. Usually, the area is
enclosed and is part of the milking center, which in turn, may be connected to the barn or located
in the immediate vicinity of the cow housing. The holding area is typically sized such that each
cow is provided 15 square feet and is not held for more than 1 hour prior to milking (Bickert et
al., 1997). The cows' udders may sometimes be washed hi this area using ground-level
sprinklers.
Milk Room - The milk room often contains the milk bulk tank, a milk receiver group, a filtration
device, in-line cooling equipment, and a place to wash and store the milking equipment (Bickert
et al., 1997). To enhance and maintain milk quality and to meet federal milk quality standards, it
is cooled from the first milking to 40°F or less within 30 minutes. Some commonly used milk
cooling devices include precoolers, heat exchangers, bulk tank coolers, and combinations of
these. The cooling fluid used is typically fresh or chilled service water. This water is still clean
and may then be used to water the animals (Bickert et al., 1997), or more commonly as milk
parlor flush water.
Milking equipment cleaning and sterilizing processes are often controlled from the milk room.
Typically, the milking equipment is washed in hot water (95 to 160 °F) in a prerinse, detergent
wash, and acid rinse cycles. The amount of water used by an automatic washing system,
including milking parlor floor washes, can vary from 450 to 850 gallons per day (Bickert et al.,
1997).
4-81
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Treatment Area - Treatment areas are used oil farms to confine cows for artificial insemination,
postpartum examination, pregnancy diagnosis,' sick cow examination, and surgery. A single stall
or a separate barn can be used as a treatment area.
i
Other Areas of the Milking Center - Milking and processing equipment is typically stored in a
utility room. This equipment may include: '
• Milk vacuum pump [
• Compressor j
• Water heater i
• Furnace
• Storage
A separate room may also be used to store cleaning compounds, medical supplies, bulk materials,
replacement milking system rubber components, and similar products. The storage room is often
separated from the utility room to reduce the deterioration of rubber products, and is typically
designed to minimize high temperatures, light, and ozone associated with motor operation
(Bickertetal., 1997). ,1
43.4.5 Rotational Grazing
I
Intensive rotational grazing is known by many terms, including intensive grazing management,
short duration grazing, savory grazing, controlled grazing management, and.voisin grazing
management (Murphy, 1988). This practice involves rotating grazing cows among several
pasture subunits or paddocks to obtain maxirnikn efficiency of the pastureland. Dairy cows
managed under this system spend all of their time, except time spent milking, out on the
paddocks during the grazing season.
During intensive rotational grazing, each paddock is grazed quickly (1 or 2 days) and then
allowed to regrow, ungrazed, until ready for another grazing. The recovery period depends on
the forage type, the forage growth rate, and the| climate, and may vary from 10 to 60 days
(USDA, 1997). This practice is labor- and land-intensive as cows must be moved daily to new •
paddocks. All paddocks used in this system require fencing and a sufficient water supply. Many
operations using intensive rotational grazing move their fencing from one paddock to another and
have a water system (i.e., pump and tank) installed in each predefined paddock area.
The number of required paddocks is determined by the grazing and recovery periods for the
forage. For example, if a pasture-type paddock is grazed for 1 day and recovers for 21 days; 22
paddocks are needed (USDA, 1997). The total amount of required land depends on a number of
factors including the dry matter content of the pasture forage, use of supplemental feed, and the
number of head requiring grazing. Generally, this averages out to one or two head per acre of
pastureland (Personal Communication: Jim Hainnawald). Successful intensive rotational grazing,
however, requires thorough planning and constant monitoring. All paddocks are typically
monitored once a week. High-producing milk cows (e.g., more than 80 pounds of milk per day)
-------
need a large forage allowance to maintain a high level of intake. Therefore, they need to graze in
pastures that have sufficient available forage or be fed stored feed (USDA, 1997).
Due to the labor, fencing, water, and land requirements for intensive rotational grazing typically
only small dairy operations (those with less than 100 head) use this practice (Personal
Communication: Jim Hannawald; USDA NRCS, 1996; CIAS, 2000a)! Climate and associated
growing seasons, however, make it very difficult for operations to use an intensive rotational
grazing system throughout the entire year. These operations, therefore, must maintain bams
and/or drylots for the cows when they are not being grazed or outwinter their milk cows
Outwmtenng is the practice of managing cows outside during the winter months. This is not a
common practice as it requires farmers to provide additional feed (as cows expend more energy
outside in the winter), provide windbreaks for cattle, conduct more frequent and diligent health
checks on the cows, and keep the cows clean and dry so that they can stay warm (CIAS, 2000b).
There are two basic management approaches to outwintering: rotation through paddocks and
sacrifice paddocks." Some farms use a combination of these practices to manage their cows
during the winter During winter months, farmers may rotate cattle, hay, and round bale feeders
throughout the paddocks. The main differences between this approach and standard rotational
grazing practices are that the cows are not rotated as often and supplemental feed is provided to
the animals. Deep snow, however, can cause problems for farmers rotating their animals in the
winter because it limits the mobility of round bale feeders. The outwintering practice of sacrifice
paddocks consists of managing animals in one pasture during the entire winter. There are several
disadvantages and advantages associated with this practice. If the paddock surface is not frozen
during the entire winter, compaction, plugging (tearing up of the soil), and puddling can occur
Due to the large amounts of manure deposited in these paddocks during the winter, the sacrifical
paddocks must be renovated in the spring. This spring renovation may consist of dragging or
scraping the paddocks to remove excess manure and then seeding to reestablish a vegetative
cover. Some farmers place sacrifice paddocks strategically in areas where an undesirable plant
grows or where they plan to reseed the pasture or cultivate for a crop (CIAS, 2000c).
Advantages of rotational grazing compared to conventional grazing include:
* Higher live weight gain per acre. Intensive rotational grazing systems result in high stocking
density, which increases competition for feed between animals, forcing them to spend more
tune eating and less time wandering (AAFC, 1999).
• .Higher net economic return. Dairy farmers using pasture as a feed source will produce more
leed value with intensive rotational grazing than with continuous grazing (USDA NRCS
1996). Competition also forces animals to be less selective when grazing They will eat
species of plants that they would ignore in other grazing systems. This reduces less desirable
plant species in the pasture and produces a better economic return (AAFC, 1999).
• Better land. Pastureland used in rotational grazing is often better maintained than typical
pastureland. Intensive rotational grazing encourages grass growth and development of
healthy sod, which in turn reduces erosion. Intensive rotational grazing in shoreline areas
4-83
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may help stabilize stream banks and could be used to maintain and improve riparian habitats
(PPRC, 1996).
• Less manure handling. In continuous grazing systems, pastures require frequent-maintenance
to break up large clumps of manure. In a good rotational system, however, manure is more
evenly distributed and will break up and disappear faster. Rotational grazing systems may
still require manure maintenance near watering areas and paths to and from the paddock areas
(Emmicx, 2000). . [ .
Grazing systems are not directly comparable to confined feeding operations, as one system can
not readily switch to the other; however, assuining all things are equal, intensive rotational
grazing systems have a number of advantages over confined feeding operations:
i
• Reduced cost. Pasture stocking systems alre typically less expensive to invest in than
livestock facilities and farm equipment required to harvest crops. Feeding costs may also be
lowered. ;
. Improved cow health. Farmers practicing intensive rotational grazing typically have a lower
cull rate than confined dairy farmers, because the cows have less hoof damage, and they are
more closely observed as they are moved from one paddock to another (USDA, 1997).
• Less manure handling. Intensive rotational grazing operations have less recoverable solid
manure to manage than confined operatiojns.
• Better rate of return. Research indicates that grazing systems are more economically flexible
than the confinement systems. For example, farmers investing in a well-planned grazing
operation will likely be able to recover mbst of their investment in assets if they leave
farming in a few years. But farmers investing from scratch in a confinement operation would
at best recover half their investments if they decide to leave farming (CIAS, 2000d).
There are a number of disadvantages associated with intensive rotational grazing compared with
either conventional grazing or confined dairy operations. The major disadvantages are:
. Limited applicability. Implementation of intensive rotational grazing systems depends upon
available acreage, herd size, land resources (i.e., tillable versus steep or rocky), water
availability, proximity of pasture area to milking center, and feed storage capabilities.
Several sources indicate that this system is used by dairy farms with less than 100 cows.
Typical confined dairy systems are often |not designed to allow cows easy access to the
available cropland or pastureland. Large [distances between the milking center and
pastureland will increase the cows expended energy and, therefore, increase forage demands.
In most of the country, limited growing seasons prevent many operations from implementing
a year-round intensive rotational grazing |system. Southern states, such as Florida, can place
cows on pasture 12 months of the year, but the extreme heat presents other problems for cows
4-84
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exposed to the elements. Grazing operations in southern states typically install shade
structures and increase water availability to cows, which in turn increases the costs and labor
associated with intensive rotational grazing systems. Because most dairy operations cannot
.provide year-round grazing, they still must maintain barns and drylot areas for their cows
when they are not grazing, and dairy operations often prefer not to have to maintain two
management systems..
• Reduced milk production levels. Studies indicate that dairy farmers using intensive
rotational grazing have a lower milk production average than confined dairy farms (USDA
NRCS, 1996). Lower milk production can offset the benefit of lower feed costs, especially if
rations are not properly balanced once pasture becomes the primary feed source during warm
months.
* Limited manure handling options. Dairies using intensive rotational grazing systems may not
be able to apply the wastewater and solid manure collected during the non-grazing seasons to
their available pastureland as crops may not be growing.
* Increased likelihood of infectious diseases. Some infectious diseases are more likely to occur
in pastured animals by direct or indirect transmission from wild animals or presence of an
infective organism in pasture soil or water (Hutchinson, 1988).
• Limited flexibility. Intensive rotational grazing systems have limited flexibility for planning
how many animals can be pastured in any one paddock. Available forage in a paddock can
vary from one cycle to another, because of weather and other conditions that affect forage
growth rates. As a result, a paddock that was sized for a certain number of cows under
adequate rainfall conditions will not be able to accommodate the same number of cows under
drought conditions (USDA, 1997).
4.3.5 Dairy Waste Management Practices
Dairy waste management systems are generally designed based on the physical state of the waste
being handled (e.g., solids, slurries, or liquids). Most dairies have both wet and dry waste
management systems. Waste with 20 percent to 25 percent solids content can usually be handled
as a solid while waste with less than 10 percent solids can be handled as a liquid (Loudon, 1985).
In a dry system, the manure is collected on a regular basis and stored where an appreciable
amount of rainfall or runoff does not come in contact with it. Handling manure as a Solid
minimizes the volume of manure that is handled.
In a slurry or liquid system, manure is often diluted with water that typically comes from flushing
system water, effluent from the solids separation system, and/or supernatant from lagoons. When
dairy manure is handled and stored as a slurry or liquid, the milking center wastewater can be
mixed in with the animal manure, serving as dilution water to ease pumping. If a gravity system
is used to transfer manure to storage, milking center wastewater may be added at the collection
4-85
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point in the barn. Liquid systems are usually favored by large dairies for their lower labor cost
and because the larger dairies tend to use automatic flushing systems.
43.5.1 Waste Collection
The collection methods for dairy manure vary depending on the management of the dairy
operation. Dairy cows may be partially, totally, or seasonally confined. As previously
mentioned, manure accumulates in confinemeiit areas such as barns, drylots, and milking parlors
and in other areas where the herd is fed and watered. In wet climates, it is difficult to collect and
store manure from unroofed areas as a solid, but it can be done if the manure is collected daily,
stored in a roofed structure, and mixed with bedding. In arid climates, manure from unroofed
areas can be handled as a solid if collection time can be flexible.
The following methods are used at dairy operations to collect waste:
• Mechanical/Tractor Scraper - Manure and bedding from barns and shade structures are
collected normally by tractor or mechanical chain-pulled scrapers. Eighty-five percent of
operations with more than 200 milking cows use a mechanical or tractor scraper (USDA
APHIS 1996b). Tractor scraping is more common since the same equipment can be used to
clean outside lots as well as freestalls and loose housing. A mechanical alley scraper consists
of one or more blades that are wide enough to scrape the entire alley in one pass. The blades
are pulled by a cable or chain drive that is set into a groove in the center of the alley. A timer
can be set so that the scraper runs two to four times a day, or continuously in colder
conditions to prevent the blade from freezmg to the floor. Scrapers reduce daily labor
requirements, but have a higher maintenance cost due to corrosion and deterioration.
• Flushing System - Manure can be collected from areas with concrete flooring by using a
flushing system. A large volume of water is introduced at the head of a paved area, and the
cascading water removes the manure. Flush water can be introduced from storage tanks or
high-volume pumps. The required volume' of flush water varies with the size of the area to
be flushed and slope of the area. The total amount of flush water introduced can be
minimized by recycling; however, only fresh water can be used to clean the milking parlor
area. Flushing systems are predominantly used by large dairies with 200 or more head
(approximately 27 percent) that tend to house the animals in a freestall-designed barn. These
systems are much less common in dairies with fewer than 200 head (fewer than 5 percent
reported using this system) (USDA APHIS, 1996b). These systems are also more common at
dairies located in warmer climates. j .
• Gutter Cleaner/Gravity Gutters - Gutter cleaners or gravity gutters are frequently used in
confined stall dairy bams. The gutters are usually 16 to 24 inches wide, 12 to 16 inches deep,.
and flat on the bottom. Either shuttle-stroke or chain and flight gutter cleaners are typically
used to clean the gutters; About three-fourths (74 percent) of U.S. dairy operations with
fewer than 100 milking cows and approximately one-third of U.S. dairy operations with 100
to 199 milking cows use a gutter cleaner (USDA APHIS, 1996b).
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• Slotted Floor - Concrete slotted floors allow manure to be quickly removed from the animal
environment with minimal labor cost. Manure falls through the slotted floor or is worked
though by animal traffic. The waste is then stored in a pit beneath the floor or removed with
gravity flow channels, flushing systems, or mechanical scrapers. The storage of animal and
milking center waste in a pit beneath slotted floors combines manure collection, transfer, and
storage.
4.3.5.2 Transport
The method used to transport manure depends largely on the consistency of the manure. Liquids
and slurries can be transferred through open channels, pipes, and in liquid tank wagons. Pumps
can be used to transfer liquid and slurry wastes as needed; however, the greater the solids content
of the manure, the more difficult it will be to pump.
Solid and semisolid manure can be transferred by mechanical conveyance or in solid manure
spreaders. Slurries can be transferred hi large pipes by using gravity, piston pumps, or air
pressure. Gravity systems are preferred because of their low operating cost.
4.3.5.3 Storage, Treatment, and Disposal
Waste collected from the dairy operation is transported within the site to storage, treatment, and
use or disposal areas. Typical storage areas for dairy waste include above- and belowground
storage tanks and storage ponds. Handling and storage methods used at dairy operations are
discussed in detail in Section 8.2.
One common practice for the treatment of waste at dairies is solids separation. Mechanical or
gravity solids separators are used to remove bulk solids from a liquid waste stream; this
separation reduces the volume of solids entering a storage facility, which increases its storage
capacity. Separation facilitates reuse of liquid in a flushing system reduces clogging of irrigation
sprinklers and reduces waste volume going to treatment or to land application sites. Manure
slurry is often separated using mechanical separators, such as stationary screens, vibrating
screens, presses, or centrifuges, all of which recover a relatively dry byproduct (Dougherty,
1998). Sedimentation by gravity settling is also used for solid/liquid separation.
Another common technology for the treatment of waste at dairies is an anaerobic lagoon.
Anaerobic lagoons are biological treatment systems used to degrade animal wastes into stable
end products. The advantage of anaerobic lagoons is their long storage times, which allow
bacteria to break down solids. Disadvantages include odors produced during environmental or
management changes and sensitivity to sudden changes in temperature and loading rates;
Anaerobic lagoons are designed to hold the following volumes: a minimum treatment volume
(based on volatile solids loading), the volume of accumulated sludge for the period between
sludge removal events, the volume of manure and wastewater accumulated during the treatment
period, the depth of normal precipitation minus evaporation, the depth of the 25-year, 24-hour
storm event, and an additional 1 foot of freeboard.
4-87
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Typical manure and waste treatment technologies used at dairy operations are discussed in detail
in Section 8.2. i
i . •
The majority (approximately 99 percent) of small and large dairy operations (fewer than and
more than 200 milking cows) dispose of their iivaste through land application (USDA APHIS,
1996b). The amount of cropland and pastureland that is available for manure application varies at
each dairy operation. Generally, dairy operations can be categorized into three groups with.
respect to available cropland and pastureland: '(1) those with sufficient land so mat all manure
can be applied without exceeding agronomic application rates, (2) those without sufficient land
to apply all of their manure at agronomic rates!, and (3) those without any available cropland and
pastureland. Operations without sufficient land, or any land, often have agreements with cither
farmers allowing them to apply manure on their land. Depending on the size of the dairy
operation, 1997 Census of Agriculture data indicate that the average acres of cropland at dairies
with at least 300 milking cows is approximately 350 acres and the average acres of pastureland is
approximately 75 acres (Kellogg, 2000). j
USDA conducted an analysis of the 1997 Census of Agriculture data to estimate the manure
production at livestock farms (Kellogg, 2000).| As part of this analysis, USDA estimated the
number of confined livestock operations that produce more manure than they can apply on their
available cropland and pastureland at agronomic rates for nitrogen and phosphorus and the
number of confined livestock operations that do not have any available cropland or pastureland.
The analysis assumed land application of manure would occur on one of 24 typical crops or
pastureland. Using the percentage of these facilities estimated by USDA against the total number
of livestock faculties, one can also estimate the number of facilities that have sufficient cropland
and pastureland for agronomic manure application. Table 4-77 summarizes the percentage of
dairy operations that have sufficient, insufficiejnt, and no land for manure application at
agronomic application rates for nitrogen and phosphorus. EPA assumes that confined heifer
operations have similar percentages. :
Table 4-77. Percentage of Dairy Operations With Sufficient, Insufficient, and No Land for
Agronomic Application of Generated Manure
Size Class
200-700 milking cows
> 700 milking cows
Sufficient Land
Nitrogen
Application
50
27
Phosphorus
Application
25
10
* No acres of cropland (24 crops) or pastureland.
Source: Kellogg, 2000
A A Tlncif Tniliictmr
Insufficient Land
Nitrogen
Application
36
. 51
Phosphorus
Application
61
68
No Land"
14
22
Beef feeding operations include facilities that Confine beef cattle for feeding or maintenance for
at least 45 days in any 12-month period. These facilities do not have significant vegetation on
88
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the beef feedlot during the normal growing season (i.e., the feedlot area does not include grazing
operations). Facilities that have beef feedlot operations may also include other animal and
agricultural operations not considered part of the feedlots, such as grazing and crop farming.
This section discusses the following aspects of the beef industry:
• Section 4.4.1: Distribution of the beef industry by size of operation and region in 1997;
• Section 4.4.2: Beef production cycles
• Section 4.4.3: Beef feedlot facility management
• Section 4.4.4: Backgrounding operations
• Section 4.4.5: Veal operations
• Section 4.4.6: Cow-calf operations
• Section 4.4.7: Beef waste management practices
4.4.1 Distribution of the Beef Industry by Size and Region
EPA's current Effluent Limitations Guidelines and Standards apply to beef feedlot operations
with a capacity of 1,000 or more slaughter steers and heifers, where the animals are fed at the
place of confinement and crop or forage growth or production is not sustained in the confinement
area.
Information presented in this section comes from USDA's National Agricultural Statistics
Service (NASS), 1997 Census of Agriculture data, and from site visits and trade associations.
The 1994 to 1998 NASS reports on beef feedlots present annual estimates of beef operations that
have a capacity of 1,000 head of cattle or more grouped in the following categories:
• Cattle inventory and calf crop
• Number of operations
• Inventory by class and size groups
• Monthly cattle on feed numbers
• Annual estimates of cattle on feed
NASS publishes only limited data for operations that have a capacity of fewer than 1,000 head of
cattle (USD A NASS, 1999e). The 1997 Census of Agriculture collects information on cattle
inventory and the number of cattle fattened for slaughter.
The capacity of a beef feedlot is the maximum number of cattle that can be held on site at any
one time and can usually be determined by the amount of feedbunk space available for the cattle.
On average, most beef feedlots operate at 80 percent to 85 percent of capacity over the course of
a year,, depending on market conditions (NCBA, 1999). In addition, most feedlots have cattle on
site for 150 to 270 days (see Section 4.4.2); therefore, on average, the feedlot can run one and
one half to two and one half "turns" of cattle each year. However, a feedlot may have anywhere
from one to three and one half turnovers of its herd per year. For example, some feedlots only
have cattle on site during the whiter months (one turnover) when crops cannot be grown, while
other feedlots move cattle through the feedyard more quickly (three and one half turnovers).
4-89 .
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EPA estimated the maximum capacity of beef Ifeedlots reported in the 1997 Census of
Agriculture using the reported sales of cattle combined with estimated turnovers and average
feedlot capacity (ERG, 2000b). :
i
Maximum Feedlot Capacity (Head) = Cattle Sales (Head) * Average Feedlot Capacity (%) / Turnovers
For example, a feedlot that sold 1,500 cattle in; 1997 and is estimated to operate at 80 percent
capacity with one and one half turnovers has an estimated maximum capacity of 800 head.
In 1997, there were approximately 2,075 beef feedlots with a capacity of more than 1,000 head in
the U.S. (USDA NASS, 1999e). These operations represent only about 2 percent of all beef
feedlots. EPA estimates that there were approximately 1,000 additional beef feedlots with a
capacity of between 500 and 1,000 head (another 1 percent of beef feedlots), 1,000 beef feedlots
with a capacity of between 300 and 500 head, and another 102,000 beef feedlots with a capacity
of fewer than 300 head. Table 4-78 shows the [estimated distribution of these operations by size
and region. Table 4-79 shows the estimated number of cattle sold during 1997 by size class.
EPA derived these data from the 1997 Census jaf Agriculture data and NASS data (ERG, 2000b).
Table 4-80 presents the number of beef feedlots by top producing states and nationally for the
following eight size categories: i
!
• -up to 299 head j
• 300 to 999 head i
• 1,000 to 1,999 head ' i . '
• 2,000 to 3,999 head |
• 4,000 to 7,999 head i
• 8,000 to 15,999 head , !
• 16,000 to 31,999 head !
• 32,000 head and greater !
The data in this table were obtained from NASJ3 and were also derived from the 1997 Census of
Agriculture data. Note that in some cases the feedlots from several size groups have been
aggregated to avoid disclosing details on individual operations for some states.
i
As one would expect, the number of feedlots decreases as the capacity increases. For example,
there are 842 feedlots in the 1,000 to 1,999 size category but only 93 hi the greater than 32,000
size category. Of the 106,075 beef feedlots acrbss all size groups in 1997, the Midwest region
has the most with 71,183 (67 percent). Nebraska and Iowa have the most large beef feedlots
(more than 1,000 head). Texas has the largest number of feedlots with a capacity of more than
32,000 head in the U.S. (41 percent). ;
4-90
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Table 4-78. Distribution of Beef Feedlots by Size and Region in 1997
Region"
Central
Mid-
Atlantic
Midwest
Pacific
South
National
Feedlot Capacity
< 300 Head
9,990
15,441
68,235
3,953
4,381
102,000"
300-500
Head
87
150
685
35
43
1,000"
500-1,000
Head
130
34
810
19
7
1,000
1,000-8,000
Head.
332
25
1,236
55
6
1,654
> SOOO Head
182
0
217
22
0
421
Total .
10,721
15,650
71,183
4,085
4,436
106,075
* CentraHDD, MT, WY, NV, UT, CO, AZ, NM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY, TO?,
NC; Midwest=ND, SD, MN, MI, WI, OH, IN, TL, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL, GA, SC, FL
" Estimated value. Assumes 98 percent of feedlots with fewer than 1,000 head have a capacity of fewer than 300 head, and 99 percent of all
feedlots with'fewer than 1,000 head have a capacity of fewer than 500 head.
Table 4-79. Cattle Sold in 1997
Size Class
< 300 Head Capacity
300-500 Head Capacity
500-1,000 Head Capacity
> 1,000 Head Capacity
All Operations
Number of Facilities
102,000
1,000
1,000
2,075
106,075
Cattle Sold
2,362,000s
600,000"
1,088,000"
22,789,000
26,839,000
Average Cattle Sold
23
600
1,088
10,983
253
a Estimated value. Value presented is the difference between total sales for all feedlots with fewer than 1,000-head
capacity, and the estimated sales for feedlots with 300-1,000 head capacity.
" Estimated value. Calculated from using the midpoint of the size range (e.g., 400 head for the 300-500 size class)
and an average turnover rate of one and one half herds a year.
4-91
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Table 4-80. Number of Beef Feedlots by Size of Feedlot and State in 1997
Location
Arizona
California
Colorado
Idaho
Iowa
Kansas
Nebraska
New Mexico
Oklahoma
South Dakota
Texas
Washington
Other States
United States
1-299
Head
151
885
1,374
894
11,839
2,563
4,700
318
1,840
2,652
3,556
1,166 "
70,062
102,000
300-
999
Head
4
25
70
13
435
160
359
6
21
124
49.
8
726
2,000
1,000-
1,999
Head
-
4b
54
19
200
45
270
-
3b
50
8
7b
191
842
Feedlot Capacity
2,000-
3,999
Head
3"
-
46
15
110"
28
181
-
-
41
13
-
85
504
4,000-
7,999
Head
-
4
32
9
,
30
118
6"
9
17
28
-
36
308
8,000-
15,999
Head
-
4
23
17"
-
34
64
-
5
6"
25
4
8
191
16,000-
31,999
Head
3
5
11
-
-
41
25
4b
3
-
35
5b
5
137
32,000 +
Head
3
7
8
-
-
17
7
-
6
-
38
-
-
93
* The number of feedlots is the number of lots operating at any time during the year. The U.S. totals show the actual number of
feedlots hi each size group. The sum of the numbers shown by states under a specified size group may or may not add to the U.S.
total for that size group because some states size groups are combined to avoid disclosing individual operations.
b Lots from other size groups are included to avoid disclosing individual operations.
Also included in the beef industry are veal operations, which are discussed in detail in Section
4.4.5, Veal operations are not specifically rep|orted in the 1997 Census of Agriculture orNASS
data. Therefore, EPA conducted site visits to veal operations and requested distribution data
from the industry to ultimately estimate the number of veal operations in the U.S., as shown in
Table 4-81 (ERG, 2000b). j
14-92
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Table 4-81. Distribution of Veal Operations by Size and Region in 1997
Region"
Central
Mid-Atlantic
Midwest
Pacific
South
Total United States
Capacity F
300-500 Calves
5
1
119
0
0
125
> 500 Calves
3
1
81
0
0
85
'Total
8
2
200
0
0
210
i^S:K«^^^
4.4.2 Beef Production Cycles
Beef feedlots conduct feeding operations in confined areas to increase beef weight gain control
feed rations, uicrease feeding efficiency, reduce feed costs, and manage animal health Calves
are often brought in from backgrounding operations to the feedlot (Section 4.4.4). Calves usually
begin the finishing" phase when they reach 6 months of age or a weight of at least 400 pounds
Cattle are typically held on the feedlot for 150 to 180 days. As stated previously in this section' a
beet feedlot may run anywhere from one to three and one half turnovers of its herd per year The
annual average steer weight at slaughter ranges from 1,150 to 1,250 pounds, while the annual
average heifer slaughter weight ranges from 1,050 to 1,150 pounds.
Some feedlots may bring in young calves at around 275 pounds and feed them on site for
approximately 270 days. As a result, these feedlot operations have fewer turnovers of the herd
per year. Based on site visits, this type of operation is typical at feedlots in southern California
Some operations may only bring in cattle during the winter months when no crops are being
grown, also resulting in fewer turnovers of the herd per year. Other operations, the true "final
finishing operations, may bring cattle in at a heavier weight and require only approximately 100
days to feed cattle, resulting in more turnovers of the herd per year. These variations in turnovers
often make it difficult to estimate farm counts if data only show cattle inventory.
4.4.3 Beef Feedlot Facility Management
This section describes factors that affect the facility management at a feedlot operation, including
the layout of feedlot systems, feeding and watering practices, water use and wastewater
generation, and climate.
4.4.3.1 Feedlot Systems
Cattle traffic flow is an important factor in the design of a feedlot. These operations use separate
vehicle and cattle traffic lanes when possible to minimize congestion, reduce the spread of
parasites and disease, and promote drainage to make pen cleaning easier and to promote animal
4-93
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comfort and welfare. Outdoor feedlot systems! comprise the following units which can be
organized in various ways.
• Office - This is usually located on or near the main access road and has truck scales and
facilities for sampling incoming feed. All bulk feed delivered to the lot enters at this point.
Cattle trucks also use these scales for in and out weights (Thompson et al., 1983).
• Feed Mill - Truck traffic around the feed mill is typically heavy. A good design allows feed
ingredients to be received while finished rations are trucked to the pens without traffic
conflict. Feeding pens are often near the feed mill to reduce travel (Thompson et al., 1983).
• Pens - Pens are designed for efficient movement of cattle, optimum drainage conditions, and
easy feed truck access. A typical pen holds 150 to 300 head but the size can vary
substantially. Required pen space may range from 75 to 300 square feet of pen space per
head, depending on climate (see Section 4J4.3.4). Space needs vary with the amount of paved
space, soil type, drainage, annual rainfall, pd freezing and thawing cycles.
i. ' •
Large feedlots use cattle alleys behind the pens to keep the flow of cattle separate from the
feed trucks. Smaller feedlots often use feeding alleys to move the cattle. The pens should
allow for proper drainage of runoff to provide comfortable conditions. A grade of at least 3
percent is necessary to allow proper drainage in most areas (Thompson et al., 1983).
. Cattle Loading and Unloading Facilities - feedlots locate these facilities to ensure the smooth
flow of trucks to bring cattle in and out of the lot. Larger feedlots typically use two shipping
areas, with the receiving area having hospital or separate processing facilities where cattle
can receive various identification markers, vaccinations, and treatment for internal and
external parasites, and are held until they are healthy enough to go to regular feeding pens
(Thompson et al., 1983); j
• Hospital Areas - These are facilities where cattle can be medically treated. Each facility
normally has a squeeze chute, refrigerator, water, and medicine and equipment storage
(Thompson et al., 1983). Approximately io percent of the cattle in a feedlot will be treated in
hospital areas during the feeding period (NCSA, 1999).
The majority of beef feedlots are open feedlois, which are usually unpaved. These types of
operations may use mounds in the pens to improve drainage and provide areas that dry quickly,
because dry resting areas improve cattle comfort, health, and feed utilization. In open feedlots,
protection from the weather is often limited to a windbreak near the fence in the winter and
sunshade in me summer; however, treatmentfacilities for the cattle and the hospital area are
usually covered. A concrete apron is typically located along feedbunks and around waterers,
because these are heavy traffic areas (Bodmaln et al., 1987).
Open-front bams and lots with mechanical conveyors or fenceline bunks are common for
feedlots of up to 1,000 head, especially in areas with severe winter weather and high rainiall.
Confinement feeding barns with concrete floprs are also sometimes used at feedlots in cold or
i 4-94
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high rainfall areas. These barns require less land and solve feedlot problems caused by drifting
snow, severe wind, mud, lot runoff, and mound maintenance. Feeding is typically mechanical
bunk feeding or fenceline bunks. Manure is usually scraped and piled in a containment area. If
the barn has slotted floors, the manure is collected beneath slotted floors, and is scraped and
stored or flushed to the end of the barn where it is pumped to a storage area for later application
(Bodman et al., 1987).
4 A.3.2 Feeding and Watering Practices
At feedyards, all cattle are fed two or three times a day and are normally fed for 120 to 180 days,
depending on their initial weight and type. Some operations may feed as long as 270 days if they
receive young calves. Feedlots consider the following factors when determining feeding
methods: the number of animals being fed; the type and size of grain and roughage storage; the
equipment necessary to unload, meter, mix, and process feed; and the location and condition of
existing feed storage (Bodman et al., 1987).
Beef feedlots use the following types of feeding methods:
• Fenceline feeding - Bunks are located along the side of a lot or pen. This method requires
twice as much bunk length as bunks that feed from both sides, but the advantage is that feed
trucks do not have to enter the pens with the cattle. Fenceline feedbunks have 6 to 14 inches
of bunk space per head, and are typically used for feedlots with more than 100 head.
Feedbunks are cleaned routinely to remove uneaten feed, manure, and other foreign.objects.
• Mechanical bunk feeding - Bunks typically allow cattle to eat from both sides and are also
used as pen dividers. This feeding method is common with continuous feed processing
systems and small operations. Mechanical feedbunks are useful for feedlots of up to 500
head.
• Self^feeding - Feedlots use haystacks, feed from horizontal silos or plastic bags, and grain
and mixed rations m bunks or self feeders with this feeding method. Portable silage and
grain bunks are useful for up to 200 head (Bodman et al., 1987).
Twenty-four hour access to the water trough is required for the health of the animals and
maximum production efficiency. Cattle water consumption varies, depending on such factors as
animal size and season, and may range from 9 gallons per day per 1,000 pounds during winter to
18 gallons per day per 1,000 pounds during hot weather (Bodman et al., 1987). Typically, one "
watering space for each 200 head and a minimum of one watering location per pen of animals is
provided (USD A NASS, 1999e). Some water may be required to add to the feed processing or to
clean equipment.
4.4.3.3 Water Use and Wastewater Generation
The main source of wastewater to be managed is the runoff from rainfall events and snow melt.
Surface runoff from rain and snow melt can transport manure, soil, nutrients, other chemicals
4-95
-------
(e.g., pesticides), and debris off the feedlot; therefore, it is important to divert clean water atway
from contact with manure, animals, feed processing and storage, and manure storage areas to
reduce the total volume of contaminated wastewater. Runoff is affected by rainfall amount and
intensity, feedlot maintenance practices, and soil type and slope. Runoff can be controlled by
using diversions, sediment basins, and storage ponds or lagoons. Feedlots can also reduce the
volume of runoff by limiting the size of confinement areas.
Typically, pens are constructed such that runoff is removed as quickly as possible, transported
from the lot through a settling basin, and diverted into storage ponds designed to retain, at a
minimum, the 24-hour, 25-year storm. Feedlots can reduce the runoff volume by preventing all
runon water from entering clean areas and by diverting all roof runoff.
Only specially constructed barns use water to flush or transport manure. These barns are used by
a very small percentage of the industry and are| typically used at smaller feedlots.
j
4.4.3.4 Climate '\
\.
I
Climate plays a large role in the design and operation of a feedlot. The metabolic requirement
for maintenance of an animal typically increases during cold weather, reducing weight gain, and
increasing feed consumption to provide more net energy. Feed consumption typically declines
under abnormally high temperatures, therefore [reducing weight gain. Investigations in California
have shown that the effects of climate-related stress could increase feed requirements as much as
33 percent (Thompson et al., 1983). As a result, waste (manure) generation would also increase.
!'
i
In cold areas, feedlots typically provide a roof of some sort for the cattle. Sheltered cattle gain
weight faster and more efficiently during winter than unsheltered cattle. Areas that receive
substantial rainfall require mud control and payed feeding areas, since higher precipitation results
in greater runoff volumes. In hot, semiarid areas, sun shades are typically provided for the cattle.
A dry climate requires generally 75 square feet of pen space per head whereas a wet climate may
require up to 400 square feet of pen space per liead (Thompson et al., 1983). Feedlots typically
use misting sprinklers or watering trucks to control dust problems in dry climates.
4.4.4 Backgrounding Operations
!
Backgrounding operations feed calves, after weaning and before they enter a feedlot using
pasture and other forages. These operations allow calves to grow and develop bone and muscle
without becoming fleshy or gaining fat covering. Weaned calves are typically sent to
backgrounding operations to allow producers to:
• Develop replacement heifers; j
• Retain rather than sell at weaning when prices are typically low;
• Use inexpensive home-grown feeds, crop residues, pasture or a combination of these to put
weight on calves economically; !
• Put weight on small calves born late in the calving season before selling; and/or
4-96
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• Put minimal weight on calves during winter before grazing on pasture the following spring
and summer.
Calves are normally kept at the operation from 30 to 60 days but can be kept up to 6 months
(approximately 400 pounds) (Rasby et al., 1996). Typical diets consist of equal proportions of
roughage and grains that produce a moderate gain of 2 to 2.5 pounds per day. Backgrounding
operations typically keep calves on pasture during their entire stay; however, these operations
may operate similarly to a beef feedlot, using pens to confine calves, and feedbunks to feed.
4.4.5 Veal Operations
Veal operations raise calves, usually obtained from dairy operations, for slaughter. Dairy cows
must give birth to continue producing milk. Female dairy calves are raised to become dairy
cows; however, male dairy calves are of little or no value to the dairy operation. Therefore, these
male dairy calves are typically sent to feedlots or veal operations. Calves are normally separated
from the cows within 3 days after birth. Veal producers typically obtain calves through livestock
auctions, although in some cases the calves may be taken directly from the dairy farm to the veal
operation (Wilson et al., 2000).
The majority of veal calves are "special-fed" or raised on a low-fiber liquid diet until about 16 to
20 weeks of age, when they weigh about 450 pounds. Calves slated for "Bob" veal, which are
marketed up to 3 weeks of age, when they weigh about 150 pounds; these constitute about 15
percent of the veal calves sold (USDA, 1998).
Calves are fed a milk-replacer diet composed of surplus dairy products, including skim milk
powder and whey powder. Their diet also includes plant- and animal-derived fats, proteins, and
other supplements such as minerals and vitamins (Wilson et al., 2000). Calves spend their entire
growing-out period on a liquid diet.
Veal calves are generally grouped by age in an environmentally controlled building. The majority
of veal operations utilize individual stalls or pens. Floors are constructed of either wood slats or
plastic-coated expanded metal, while the fronts and sides are typically wood slats. The slotted
floors allow for efficient removal of waste. The back of the stall is usually open, and calves may
be tethered to the front of the stall with fiber or metal tethers. Individual stalls allow regulation
of ah- temperature and humidity through heating and ventilation, effective management and
handling of waste, limited cross-contamination of pathogens between calves, individual
observation and feeding, and, if necessary, examination and medical treatment (Wilson et al.,
2000). The stalls provide enough room for the calves to stand, stretch, groom themselves, and lie
down in a natural position.
Veal waste is are very fluid, diluted by various volumes of wash water used to remove them from
the building (see Section 6.4 for a discussion of veal manure characteristics). Therefore, manure
is typically handled in a liquid waste management system. Manure, hair, and feed are regularly
washed from under the stalls to reduce ammonia, odor, and flies in the room. Manure is typically
washed out twice daily so that if the calf is having health problems, it is easily observed.
4-97
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Approximately 10 percent to 30 percent of the wastewater generated at a veal operation comes
from scrubbing rooms and stalls after calves have been shipped to market.
The most common method for handling manure and wash water is using a sloping gutter under
the rear of the stalls, allowing manure to continuously drain into a manure storage system.
Tanks, pits, and lagoons are used to store manure until it is spread on fields. Storage pits may
also be built directly under buildings; however, this produces higher levels of ammonia and other
pit gases that require increased ventilation and higher fuel costs in the winter (Meyer, 1987).
4.4.6 Cow-Calf Operations j
I
i • ...
Cow-calf operations breed mature cows and yearling heifers with bulls to produce calves and can
be located in conjunction with a feedlot, but they are more often as stand-alone operations. A
herd of mature cows, some replacement heifers, and a few bulls are typically maintained at cow-
calf operations on a year-round basis. Offspring calves remain with the cows until weaned and
then maybe held in different pastures to grow.until they weigh between 650 to 750 pounds when
they are sold to feedlots as yearlings. These operations may also sell their calves to
backgrounding operations or dairy operations. Artificial insemination is not commonly used at
cow-calf operations. Bulls are typically used for breeding and are placed with cows at the proper
time to ensure spring calves. j
The number of bulls required at a cow-calf operation depends on the number of cows and heifers,
size and age of bulls, crossbreeding program, available pasture, and length of breeding season. ^
One bull is typically provided for each set of 25 cows or heifers. Bulls are usually pastured away
from the cows, and they may be penned separately from each other to prevent fighting (Bodman,
1987). !
i • • •
Outdoor calving requires clean, well-drained, and wind-protected pastures. Separate feed areas
are provided for mature cows, first calf heifers, bulls, and calves (Loudon, 1985). In cold
climates, a calving barn may be needed to reduce the risk of death. These barns typically include
a loose housing observation area, individual pens, and a chute for holding and treating cows.
Typically, a bam is provided for 5 percent to 10 percent of the cow herd in mild climates, and for.
15 percent to 20 percent of the herd in more severe weather or during artificial insemination
(Bodman, 1987).
4.4.7 Waste Management Practices
Waste from a beef feedlot may be handled as a' solid or liquid; both management methods have
advantages and disadvantages. Waste from a yeal operation is handled as a liquid. Solid waste is
typically found in calving pens and in open lots with good drainage. Semisolid waste has little
bedding and no extra liquid is added. Waste treated as a solid has a reduced total volume and
weight because it contains less water; therefore, its management may cost less and require less
power.
-98
-------
Slurry waste has enough water added to form a mixture that can be handled by solids handling
pumps. Liquid waste is usually less than 8 percent solids, and large quantities of runoff and
precipitation are added to dilute it. Wastes treated as a liquid are easier to automate and require
less daily attention; however, the large volumes of added water increase the volume of waste. As
a result, the initial cost of the liquid-handling equipment is greater (USDA NRCS, 1992).
4.4.7.1 Waste Collection
Beef cattle are confined on unpaved, partially paved, or totally paved lots, and much of their
manure is deposited around feedbunks and water troughs. Feedlots typically collect these wastes
from the feedlot surfape after shipping each pen of cattle (Sweeten, n.d.).
The following methods are used in the beef industry to collect waste:
• Scraping - This is the most common method of collecting solid and semisolid manure from
both barns and open lots. Solids can be moved with a tractor scraper and front-end loader. A
tractor scraper may be used in irregularly shaped alleys and open areas. Mechanical, scrapers
are typically used in the pit under barns with slotted floors and propelled using electrical
drives attached by cables or chains. Tractors have fewer problems and work better on frozen
manure; however, mechanical scrapers reduce labor requirements. Removing manure
regularly reduces odor in enclosed areas. Scraping is common for medium and large feedlots
(Loudon, 1985).
• Slotted Flooring - This term refers to slats and perforated or mesh flooring and is a method of
rapidly removing manure from an animal's space. Most slats are reinforced concrete, but can
be wood, plastic, or aluminum, and are designed to support the weight of the slats plus live
load, which includes animals, humans, and mobile equipment. Manure drops between slats,
which keeps the floor surface relatively clean. Wide slats (between 4 and 8 inches) are
commonly used with 1.5 to 1.75 inches between slats (Loudon, 1985).
• Flushing System - This type of system dilutes manure from beef feedlots with water to allow
for automated handling. Diluting the manure increases its volume and therefore requires a
larger capital investment for equipment and storage facilities. The system uses a large
volume of water to flush manure down a sloped gutter to storage, where the liquid waste can
be transferred to a storage lagoon or basin. The amount of water typically used for cleaning
is 100 gallons per head at least twice a day. Grade is critical for the flush alleys as is amount
of water used (Loudon, 1985). This system is not very common for large feedlots; however,
this type of system is widely used at veal operations.
Waste collection is easiest on paved lots. On unpaved lots, cattle traffic tends to form a seal on
the soil that reduces the downward movement of contaminated water; however, deep scraping
can destroy the interface layer that forms between the manure and the soil and acts as a seal to
decrease the chance of pollutants from entering the groundwater.
4-99
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To reduce the production of unnecessary waste, clean water can be diverted away from the
feedlot area. For example, uncontaminated water can be directed away from the waste and
carried outside of the feedlot area. Roof runoff can be managed using gutters, downspouts, and
underground outlets that discharge outside the feedlot area. Unroofed confinement areas can
include a system for collecting and confining contaminated runoff. Paved lots generally will
have more runoff per square foot than unpaved lots, but due to a smaller total area, they will-have
less total runoff per animal. ;
i
i
4.4.7.2 Transport
Waste collected from the feedlot may be transported within the site to storage, treatment, and use
or disposal areas. Solids and semisolids are typically transported using mechanical conveyance
equipment, pushing the waste down alleys, and transporting the waste in solid manure spreaders.
Flail-type spreaders, dump trucks, or earth movers may also be used to transport these wastes..
Liquids and slurries, typically found at veal operations, are transferred through open channels,
pipes, or in a portable liquid tank. These wastes can be handled by relying oil gravity or pumps
as needed. i
4.4.73 Storage, Treatment, and Disposal
Beef feedlot operations typically use a settling basin to remove bulk solids from the liquid waste
stream, reducing the volume of solids before die stream enters a storage pond, thereby increasing
storage capacity. A storage pond is typically designed to hold the volume of manure and
wastewater accumulated during the storage period, the depth of normal precipitation minus
evaporation, the depth of the 25-year, 24-hour storm event, and an additional 1 foot of freeboard.
Solid manure storage can also range from simply constructed mounds to manure sheds that are
designed to prevent runoff and leaching. !
Beef feedlot operations may also use other types of technologies, such as composting or
mechanical solids separation, when managing animal waste and runoff. Typical manure and
waste handling, storage, and treatment technologies used at beef feedlots are discussed in detail
in Section 8.2. The majority (approximately 83 percent) of beef feedlots dispose of their waste
through land application (USDA APHIS, 2000a).
Veal operations typically use an underground |storage pit or a lagoon for waste storage and
treatment. Veal operations also typically dispose of their waste through land application.
The amount of cropland and pastureland that is available for manure application varies at each
beef operation. Generally, operations in the bbef industry can be categorized into three groups
with respect to available cropland and pastureland: (1) those with sufficient land so that all
manure can be applied without exceeding agronomic application rates, (2) those without
sufficient land to apply all of their manure at agronomic rates, and (3) those without any available
cropland and pastureland. Operations without sufficient land, or any land, often have agreements
with other farmers allowing them to apply mahure on their land. Depending on the size of the
beef operation, 1997 Census of Agriculture data indicate that the average acreage of cropland at
[4-100
-------
beef feedlots with at least 500 head is between 550 to 850 acres and the average acreage of
pastureland is between 50 and 110 acres (Kellogg, 2000).
USDA conducted an analysis of the 1997 Census of Agriculture data to estimate the manure
production at livestock farms. As part of this analysis, USDA estimated the number of confined
livestock operations that produce more manure than they can apply on their available cropland
and pastureland at agronomic rates for nitrogen and phosphorus and the number of confined
livestock operations that dp not have any available cropland or pastureland. The analysis
assumed land application of manure would occur on 1 of 24 typical crops or pastureland
(Kellogg, 2000). Using the percentage of these facilities estimated by USDA against the total
number of livestock facilities, one can also estimate the number of facilities that have sufficient
cropland and pastureland for agronomic manure application. Table 4-82 summarizes the
percentage of beef feedlots that have sufficient, insufficient, and no land for manure application
at agronomic application rates for nitrogen and phosphorus. EPA assumes that all veal
operations have sufficient land to apply their manure.
Table Table 4-82. Percentage of Beef Feedlots With Sufficient, Insufficient,
and No Land for AgronomicApplication of Manure
Size Class
300 -1,000 head
1,000 -8,000 head
> 8,000 head
Sufficient Land
Nitrogen
Application
84
6
8
Phosphorus
Application
62
22
1
Insufficient Land
Nitrogen
Application
9
21 '
53
Phosphorus
Application
31
67
6
No Land"
7-
11
• 39
1 No acreage of cropland (24 crops) or pastureland.
Source: Kellogg, 2000
4.5 References
Abt. 1998. Preliminary study of the livestock and poultry industry: Appendices. Abt Associates
Inc., Cambridge, Massachusetts.
Adams, R. S., et al. 1995. Dairy reference manual. 3rd ed. Northeast Regional Agricultural
Engineering Service Cooperative Extension.
AAFC. 1999. Farming for tomorrow: Conservation facts. Rotational grazing: The rest and
recovery method of pasture management. Agriculture and Agri-Food Canada,
. Accessed February 2000.
Aust, P. 1997. An institutional analysis of vertical coordination versus vertical integration: The
case of the US broiler industry. Michigan State University, Department of Agricultural
Economics, East Lansing, Michigan.
4-101
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Bagely, P.C. and Evans, R.R. 1998. Broiler litter as a feed or fertilizer in livestock operations.
Mississippi State University Extension Service, cooperating with U.S. Department of
Agriculture, Washington, DC. .
I • • . .
Barflett, R, J. Laird, C. Addison, and R. McKiellar. 1993. The analysis of egg wash water for the
rapid assessment of microbial quality. Poultry Science. 72:1584-591.
Bickert, W.G., G.R. Bodman, B J. Holmes, D!.W. Kammel, J.M. Zulovich, and R. Stowell,. 1997.
Dairy freestall housing and equipment, ,6th ed. Midwest Plan Service, Agricultural and
Biosystems Engineering Department.
' ' f
Bocher, L. W. 2000. Custom heifer grower, specialize in providing replacements for dairy
herds, Hoard's Dairyman.
i • ' •
Bodman, G.R., D.W. Johnson, D.G. Jedele, V[.M. Meyer, J.P. Murphy, and H.L. Person. 1987.
Beef housing and equipment handbook. 4t!h ed. Midwest Plan Service.
i
i ,
Bradley, K, D. Bell, R. Ernst, D. McMartin, and J. Milliam. 1998. Animal care series: Egg-type
layer flock care practices. California Poultry Workgroup, University of California
Cooperative Extension, University of California Publishing, Davis, California.
Brbdie, H.L. Carr, and C. Miller. 2000. Structures for broiler litter manure storage.
Cooperative Extension System, University of Maryland System, College Park, Maryland .
. Accessed November 2000.
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Agricultural Systems, . Accessed May
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CHAPTERS
INDUSTRY SUBCATEGORIZATION FOR
EFFLUENT LIMITATIONS GUIDELINES AND STANDARDS
5.0 INTRODUCTION
The Clean Water Act requires EPA to consider a number of different factors when developing
Effluent Limitations Guidelines and Standards (ELG) that represent the best available technology
economically achievable for a particular industry category. These factors include the age of the
equipment and facilities, the manufacturing processes employed, the types of treatment
technology to reduce effluent discharges, and the cost of effluent reductions. One way the
Agency takes these factors into account is by breaking down categories of industries into separate
classes of similar characteristics. The division of a point source category into groups called
"subcategories" provides a mechanism for addressing variations among products, raw materials,
processes, and other parameters that can result in distinct effluent characteristics. This provides
each subcategory with a uniform set of effluent limitations guidelines that take into account
technology achievability and economic impacts unique to that subcategory.
hi developing the CAFO ELG, EPA assessed the factors described above and developed
additional factors that specifically address the characteristics unique to CAFOs. Furthermore,
EPA reviewed the existing ELG supporting documents for the basis for subcategorization.
Finally, it is EPA's goal to simplify this regulation by revising both the ELG and the NPDES
permit regulations together, and to develop a subcategorization scheme consistent with both
regulations. For this proposal, EPA considered Ihe following factors:
5.1.1 Basis for the existing ELG (40 CFR Part 412)
5.1.2 Production processes
5.1.3 Animal type
5.1.4 Water use practices
5.1.5 Wastes and wastewater characteristics
5.1.6 Facility age
5.1.7 Facility size
5.1.8 Geographical location
5.1.9 Pollution control technologies
5.1.10 Non-water quality environmental impacts
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5.1 Factors Considered as the Basis for Subcategorization
EPA considered a number of potential Subcategorization approaches for CAFOs. EPA used
information collected during site visits as well! as outreach communications with the industry to
develop these approaches. A brief discussion of each approach is presented below.
5.1.1 Basis for Subcategorization in the Existing ELG
EPA developed the Subcategorization in the existing ELG (40 CFR Part 412) on the basis of
animal type, housing, and numbers of animals j(USEP A, 1974). As one option for revision, EPA
considered maintaining the existing basis of Subcategorization, and refining the performance
standards for these facilities (described in Chapter 9 as Regulatory Scenario 4 where the ELG
applicability is established at 1,000 AU). EPA also considered expanding the scope of the ELG,
and considered the existing Subcategorization as the basis (described hi Chapter 9 as Regulatory
Scenarios 2 and 3). The subcategories analyzed under the existing ELG are listed below:
• beef cattle, open lot
• beef cattle, housed lot
• dairy cattle, stall barn
• dairy cattle, free stall bam
• dairy cattle, cowyard with milking center
• swine, open dirt or pasture
• swine, slotted floor house
• swine, solid concrete floor
• . chickens, broilers
• chickens, layers
• chickens, layer breed and replacement
• turkeys, open lot I
• turkey, housed lot j '••
EPA developed model farms to distinguish animal type, current housing types, and numbers of
animals that could be used to evaluate costs for each existing potential subcategory. EPA notes
that the industries have changed operational practices considerably hi the past few decades. EPA
and industry stakeholders both agreed that the basis for Subcategorization needed to reflect
current industry trends. Stakeholders suggested EPA should consider elimination of any
reference to outdated technologies such as continuous flow watering systems for poultry. EPA
also notes that changes in production processes have essentially excluded swine nurseries and
dairy heifer operations. Finally, EPA notes that the analysis for the animal types listed above
reflect assumptions regarding animal sizes, ages, and/or weights that were common to the
industry in 1974. In many cases, these parameters are substantially different today than they were
in 1974 (See Chapter 4). Nevertheless, EPA determined animal types were still an important
factor that needed to be further evaluated. Animal type is further described in section 5.1.3.
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5.1.2 Production Processes
EPA interpreted "production processes" to be the production of meat, eggs, or milk by CAFOs.
The production process also includes the housing systems commonly used. Manure handling and
treatment are discussed in section 5.1.9. One basis for subcategorization is the type of
production system in place; for example, the swine production pyramid of breeding, nursery, and
finishing could be used as a basis of subcategorizing swine CAFOs. In consultation with the
industry, EPA determined there were too many life-cycle variables to allow.reasonable
subcategorization, and that segmentation based on these variables was unlikely to result in
substantially different effluent guidelines and standards. In the case of chickens, such an
approach would result in over a dozen subcategorizations that overlap. The applicable
subcategory could also vary for each group of animals produced at a given operation. EPA
determined segmentation in this fashion would complicate rather than simplify the regulation.
Another approach could be based on building type or confinement practice; for example, open
lots, stall barns, and total confinement housing could be used as a basis for subcategorization.
EPA collected sufficient data to warrant development of a new subcategory for veal, which was
previously included in the beef cattle subcategory. Veal operations confine fewer animals than
do many beef feedlots, and veal are usually maintained in housing where wastes are stored in
lagoons or tanks. As discussed in Chapter 10, EPA also found the bases for BAT and NSPS for
veal operations are different than that for beef cattle.
EPA also determined that the previous basis for separating wet and dry poultry operations was
inappropriate. EPA developed model farms by size (number of birds), location (region), and
function (broiler or layer) to further evaluate production processes. EPA did not find that these
factors influenced the ability for the regulated industries to achieve the performance standards.
Furthermore, since broilers and layers both are mostly dry manure systems, and since it would
complicate the regulation by segmenting each subsector, EPA decided not to segment the
industry for the proposed rule.
For the other animal sectors, EPA looked at and determined that there was no reason to segment
the industry. EPA's data and site visits indicated that facilities often managed animals in more
than one fashion at a single location, and furthermore, that such a subcategorization could
actually provide disincentives for facilities to employ new technologies. Nevertheless, EPA
acknowledges production processes are an important factor in distinguishing various facilities,
and developed its cost models to reflect the differences in production processes. Cost estimates
developed for the various technology options described in Chapter 10 indicate that differences in
production processes do not consistently influence the ability of the facility to achieve the
performance standards.
5.1.3 Animal Type
EPA considered both animal type and animal maturity as a possible means of subcategorization.
Animal type is clearly a significant factor and was successfully used as the first level of
5-3
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categorization in the existing ELG. However, ithe animal breed, animal weight, number of turns
produced, feed and water consumption, manure production, manure contents, and production
system vary not only by animal type, but also by animal function and maturity. These differences
suggest further evaluation of animal function and animal maturity for the purposes of
subcategorization. For example, sows for breeding are often confined, fed, housed, and
maintained differently from nursery pigs or finishing pigs. Chickens raised for meat production
are a different breed of chicken, have a different weight, eat a different diet, and are raised
differently than those used for egg production.! Such an approach cpuld also mean a beef feedlot
would have to track the average weights of each animal breed and age on the facility. Many
other production related factors are necessarily complicated, such as fluctuating market demands,
number of rums the facility produces annually,; efficiency of a given animal or breed of animal to
assimilate feed, costs and makeup of feed, and'many other highly variable factors. These factors
do not lend themselves to industry segmentation.
EPA notes two cases where the existing regulation needed clarification regarding scope of certain
animal types: immature swine and immature dairy. The existing regulation only counted those
swine that weigh more than 55 pounds, and accounts for only the confined mature dairy (whether
milked or dry) when determining the applicability for the dairy operation. Some stakeholders
perceive an inconsistency between sectors and how CAFOs are defined, and consider the
inconsistency a major loophole. Therefore, EPA collected data on the numbers and sizes of
operations that confine immature animals.
In the 1970s, farms that confined only nursery pigs were relatively scarce. The vast majority of
these operations maintained all phases of swine production (farrow to finish) at one location.
The size of a swine operation was readily identified by the number of sows or the number of
finishing pigs kept on site. Swine nurseries may have been located in separate buildings, but the
animals were still maintained at the same site. ! Since the regulations applied to the entire facility
and all animals kept in confinement, once a facility was defined as CAFO for one group of
animals, all animals and manure generated in confinement were considered part of the CAFO.
Though half of the swine industry today still practices farrow-to-finish production, and the vast
majority of the remaining operations are grow-finish operations, the increased use of contracts to
handle certain phases of production and the increased specialization found in the swine
production pyramids has resulted in the emergence of operations that solely confine nursery pigs
(i.e. swine weighing less than 55 pounds). Even in the 1990s, there were an estimated 100
operations that only confine immature swine (i.e. nurseries). However, EPA data indicates such'
operations are increasing in both number and size, and looked at ways to subcategorize these
operations and include them under the revised regulatory scope.
i
EPA considered a number of mechanisms for covering immature swine. The simplest approach
is to count all swine, regardless of size or age. EPA determined counting all animals would
double the effective size of operations that have breeding functions. While this would include
nursery facilities, this approach also changes thle existing basis without improving the regulation.
Alternatively, all swine would be counted but a. weighting factor could be used to distinguish
animal sizes. This approach is inconsistent with EPA's attempt to simplify the regulations by
5-4
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removing mixed animal multipliers and animal unit calculations. Furthermore EPA believes the
current subcategorization is still effective for regulating all but those facilities that house
immature swine only. To target the perceived immature animal loophole, EPA selected the
approach of counting both numbers of mature swine and numbers of immature swine, either one
of which could define the facility as a CAFO. Once a facility is defined as a CAFO for either age
group of animals, all animals in confinement would be considered as part of the CAFO. This
approach minimizes changes to the applicability to most facilities with mature swine, though it is
possible some breeding facilities with high numbers of pigs per litter could now be defined as a
CAFO.
The existing regulation also applies to operations confining mature dairy, whether milked or diy.
In the 1970s, most dairies maintained calves and heifers for replacement on site, though such
animals were frequently kept on pasture. The number of heifers and calves kept varied from
year to year and by season, but the milking herd was relatively constant. Bulls, when kept on site
at all, were few in number. The threshold for dairy already takes into account housing and
management of animals at dairies, including the frequent use of pasture to keep some animals.
EPA still believes the threshold based on mature dairy inherently accounts for some calves and
heifers being kept in confinement. For reasons described above, EPA elected to continue to
count only mature animals at a dairy.
Since the 1970s, some dairy'operations have focused time and resources on the actual milking
herd, and have elected not to keep heifers and calves on site. An estimated 18% dairies use
contract heifer operations to keep the heifers until needed. Though EPA estimates there are
fewer thanlOO large heifer operations, the trend continues for offsite management of heifers.
Such heifer operations may use pasture, but more commonly use a feedlot type system for
maintaining the animals. Therefore, EPA proposes to count heifers maintained separately from
the milking herd using the same basis as beef cattle. Note that both beef cattle and heifers are
counted together under this approach.
In addition to animal type and age, EPA performed additional analysis on animal function:
pullets for replacement, turkeys for breeding, swine breeding facilities, swine finishing facilities,
swine nurseries (swine under 55 pounds), and beef backgrounding yards. However, EPA
believes segmentation of the industry to reflect these other animal functions would not improve
practicability of the regulation. Many facilities could fall under more than one applicability,
causing additional confusion in implementing applicable regulatory requirements. EPA
concluded size and age of animal was only appropriate for the purpose of including those
animals previously unspecified in the applicability of the ELG.
5.1.4 Water Use Practices
EPA considered water use practices at dairy, swine, and layer facilities employing liquid or semi-
solid based technologies such as flush waste handling systems,, deep pits, and scrapers. In
considering these practices as a basis for subcategorization, first EPA costed the dairy industry
for scrape or flush, and conservatively costed all swine facilities as utilizing flush type manure
5-5
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handling systems. EPA costed these sectors for the various technology options, and concluded
water use practices did not prevent a facility from achieving performance standards. EPA
determined a subcategorization based on wateriuse practices could in some cases provide a
disincentive for a facility to reduce fresh water consumption. Therefore, EPA did not select
water use practices as a basis for subcategorization.
5.1.5 Wastes and Wastewater Characteristics
EPA analyzed data available from USDA, universities, industry, and the literature. For a given
animal type, there is reasonably consistent manure generation, and similar pollutant generation.
However, site specific factors such as animal management, feeding regiments, and manure
handling will affect the form and quantity of the final waste products. EPA determined nutrients
were the primary pollutant of concern, and evaluated some methods of subcategorization based
on nutrient generation. !
EPA considered a method for comparing sows and nursery pigs to finishing pigs where the
method looks at manure, nitrogen, phosphorus,! BOD5, and volatile solids (VS) on a per pound
(Ib) animal basis. Depending on the metric use|d, from 9,000 to 12,000 immature pigs equate to
2,500 finishing pigs (or equivalent to 1,000 AU of swine). Therefore EPA selected 10,000 swine
under 55 pounds as the equivalent of 2,500 mature swine. See Section 5.1.3 for additional
discussion of immature animals.
Manure/litter can be treated and reused as bedding materials, and wastewaters can be recycled for
washing or flushing, but ultimately all manure nutrients will be land applied. Even manure
processed into value added products (such as pelletizing or composting) or used for alternative
uses (such as incineration or digestion) will eventually be land applied. Therefore, EPA
considered an approach that evaluated the nutrient content of the manure, namely phosphorus.
One method of nutrient based subcategorization would use published USDA NRCS manure
nutrient values to determine a threshold at which a facility would be defined as a CAFO. One
limitation to such an approach is that it would not encourage management strategies to reduce
nutrient content of the manure, and the approach does not consider the form of the nutrient, only
the presence of the nutrient. Form of the nutrient (i.e. organic or inorganic) is especially
important where land application of manure should be done with the intention of nutrient
assimilation by the crop and soil.
EPA considered another approach by which the mass of a particular nutrient (i.e. phosphorus)
could be used as a basis for categorization. This approach encourages nutrient management and
conservation, however this approach was not selected due to its costs, complexity, and potential
additional requirements for rigorous sampling. Furthermore, the approach would not allow for
site specific determination of the land application rate for any other nutrient. EPA also did not
select a. particular pollutant such as nutrients as a basis for subcategorization because nutrients :
(such as phosphorus) may be an important consideration today, but in the future the focus may
shift to some other parameter such as metals or pathogens.
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5.1.6 Facility Age
EPA evaluated the age of facilities as a possible means of subcategorization because older
facilities may have different processes and equipment which could result in different wastewater
characteristics. These differences may require significantly greater or more costly control
technologies to comply with regulations.
During site visits EPA looked at facilities of all ages. EPA believes these older facilities are
subject to full compliance with state and federal regulations just like the newer facilities, hi
addition, many older facilities are similar to newer facilities because they have improved,
replaced, or modified equipment and practices over time. For example, many wet layer facilities
are retrofitting to dry manure systems, few if any large swine facilities use open lots, and
ventilation systems are replaced with newer technologies. Even though confinement housing
may be considered to have a 20 to 30 year useful life, modifications are continuously made to
the internal structures such as replacement of floor materials, new feeding systems, and updated
drinking water equipment. These and other examples are documented hi the record (See W-00-
27, Section 5.3).
As described in Chapter 6, wastes and wastewater characteristics are predominantly dependent
on animal type' and animal age. The age of th& facility is also taken into consideration through
the production process factor. Treatment, storage, method of manure handling, and other forms
of manure management will affect the form of the manure and wastewaters generated. However,
the age of the facility does not have an appreciable impact on the wastewater characteristics and
was not considered as a basis for subcategorization.
5.1.7 Facility Size
EPA considered subcategorization on the basis of facility size. EPA analyzed several size groups
for each major livestock sector, including the existing ELG applicability threshold of 1,000 AU
(see Chapter 11 for the size groups analyzed). Within each size group EPA considered the
predominant practices, and developed cost models to reflect these baseline practices. EPA found
facilities may use different treatment, storage, and handling practices based on size, but for the
size of facilities under consideration for revisions to the ELG (i.e. >300 AU), facilities of all
sizes generally use similar practices. The animal breeds (i.e. preferred animal strains and
genetics) maintained also do not vary measurably by facility size, and therefore there is very little
variation in manure and waste characteristics.
EPA adjusted costs for each size group modeled to reflect these baseline characteristics.
Essential requirements governing waste management are closely related for all sized facilities.
For some technology options the costs to meet the performance standards may affect more
smaller operations, such as fixed costs for groundwater assessments. For other technology
options, such as land application standards, smaller facilities are better able to meet the
performance standards. EPA did not find that farm size consistently influenced the ability of the
facilities to achieve the performance standards for each technology option (see the EA for more
5-7
-------
information on impacts). Furthermore, pollution potential from AFOs (i.e. >300 AU) is
approximately the same per unit of animal production for all sizes of facilities. Finally, to
minimize confusion, inconsistencies, and administrative burden, EPA intends to set the ELG to
apply to anyone defined as a CAFO. EPA thus determined that the industry should not be
subcategorized on the basis of facility size.
5.1.8 Geographical Location .
EPA considered subcategorization on the basis ;of geographical location. EPA analyzed key
production regions for each major livestock sector (see Chapter 11 for definitions of the regions
analyzed). Animal breeds maintained and therefore manure and waste characteristics do not vary
measurably by region. Within each region EPA considered the predominant practices (see
Chapter 4), and developed cost models to reflect these baseline practices. EPA identified
different treatment, storage, and handling practices based on location for the size of facilities
under consideration for revisions to the ELG (i.;e. >300 AU). Treatment technologies vary by
location, as does performance of technologies such as anaerobic lagoons, evaporation ponds, and
methane recovery lagoons. Costs to install andioperate certain technologies such as storage and
manure handling equipment will vary by location. This distribution of costs and practices by
location suggests subcategorization based on geographic distribution. EPA also recognizes
geographic location may have an affect on the market for raw materials and products, the
predominance of contractual relationships, and "the value of the products. These issues are
addressed in the Economic Assessment Document (EA).
Two factors are especially subject to geographical location, specifically the availability of
cropland for application of manure and the selection of manure handling and storage practices
appropriate to the local climate. However, these factors encourage conservation by efficient use
of water, including recycle and reuse, and encourages the installation of practices for the entire
category to reduce treatment costs, reduce hauling costs, improve distribution of manure
nutrients, and improve pollutant removals. These new practices may also positively affect non-
water quality environmental impacts. Ultimately, the impact of location and climate is so highly
variable as to prove unreliable in defining subcategories.
i • .
5.1.9 Pollution Control Technologies ',
s*'
EPA evaluated water pollution control technologies currently being used by the industry as a
basis for establishing regulations. Treatability of wastes was not a factor for categorization since
wastes from CAFOs are concentrated and present in such quantities that no direct discharge from
the production area is allowed. Furthermore, pollution control technologies are often
complementary to or directly part of the production process, and the rationale for not using
production processes as a basis for subcategorization also apply. See 5.1.2 for a further
discussion of production processes. Finally, use of pollution control technologies to segment the
industry may result in disincentives for new and innovative treatment technologies.
5-8
-------
5.1.10 Non-Water Quality Environmental Impacts
Non-water quality impacts from the CAFO result from transportation of manure and wastes to
off-site locations, and emissions of volatile organic compounds to the air. While non-water
quality characteristics are of concern to EPA, the impacts are the result of individual facility
practices and do not apply uniformly to different industry segments. To the extent there are
similarities, these similarities do not lend themselves towards subcategorization of the industry hi
a way that provides better controls than the proposed approach. Therefore non-water quality
impacts are not an appropriate basis for subc'ategorization. Chapter 13 provides further
information concerning non-water quality impacts of CAFOs.
5.2 Proposed Revised Subcategories
Animal type is a significant factor and was used as the first level of subcategorization. Animal
age was used as the second level of subcategorization for swine and mature dairy cattle. EPA is
not proposing changes to the ELG for the sheep or lambs, horses, or ducks subcategories. The
proposed revisions to the ELG subcategories are presented in the following table. The table
indicates the minimum number of animals that defines the facility as a CAFO in the NPDES
regulations. Once defined as a CAFO, the ELG applies to that facility.
Table 5-1. Revised ELG Applicability
Subcategory
Veal
Mature dairy cattle
(whether milked or dry)
Cattle other than mature
dairy or veal
Swine each weighing over
25 kilograms
Swine each weighing less
than 25 kilograms
Turkeys
Chickens
Minimum Number of Animals to be Defined as a CAFO
Two-Tiered NPDES Scenario
500
350
500
1,250
5,000
27,500
50,000
Three-Tiered NPDES Scenario
300
200
300
750
3,000
16,500
30,000
5-9
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5.3 References .
USEPA. 1974. Development Document for Effluent Limitations Guidelines and New Source
Performance Standards - Feedlots Point Source Category. U.S. Environmental Protection
Agency, Washington, DC.
5-10
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CHAPTER 6
WASTEWATER CHARACTERIZATION
AND MANURE CHARACTERISTICS
6.0 INTRODUCTION
This chapter describes waste streams generated by the animal feeding industry. Differences in
waste composition and generation between animal types within each sector are highlighted.
The types of animal production and housing techniques determine whether the waste will be
managed as a liquid, semisolid, or solid (Figure 6-1). The type of manure and how it is collected
have a direct impact on the nutrient value of the waste and its value as a soil amendment or for
other uses.
PERCENT TOTAL SOLIDS
10 19 20
LIQUID SEMISOLID
WATER ADDED
PUMPABLE
LIQUID MANURE
HANDLING SYSTEMS
AS EXCRETED
SCRAPER Al
SOL
MDB
SOLID
BEDDING ADDED
JCKETLOAD
STACKABLE
0 MANURE
HANDLING SYSTEMS
Figure 6-1. Manure characteristics that influence management
options (after Ohio State University Extension, 1998).
6.1 Swine Waste
Swine waste contains numerous chemical and biological constituents such as nutrients, heavy
metals, and pathogens that can potentially contaminate the environment. The composition of
swine waste and rate of its excretion by the pig vary with the stage of physical development, the
pig's gender, and if a female whether she is farrowing. As noted in Chapter 4, during the course
of then: life cycle, pigs receive up to six different diets to maximize growth at each stage of
physical development. Each diet is composed of a unique mix of nutrients and minerals and
those differences are reflected in the different composition of manure generated over the pig's
life.
6-1
-------
Swine waste also undergoes physical and chemical changes after it has been excreted by the pig.
For example, swine waste volume and composition change after the waste becomes mixed with
water, feed, and bedding materials. Furthermore, microbial activity alters the chemical makeup
of the waste by metabolizing organic matter and generating chemical by-products. Additional
chemical changes can occur depending on how the waste is stored and whether it is treated.
For swine operations, typical manure handling practices are designed to produce either a liquid or
a semi-solid. Thus, the nutrient component of manure usually becomes more dilute because of
the addition of water used to aid in collection of the manure. In addition, amnionia volatilization
reduces nitrogen concentrations in both liquid and dry manure handling systems. Phosphorus
concentrations increase in manure that is handled dry as the water content decreases.
As discussed in Chapter 4, swine manure typically is collected and stored by means of pit
storage, lagoons, or a combination of the two. Most lagoons operate anaerobically. Aerated
lagoons have received less attention because of their higher costs; however, the potential for
decreased odor might increase their use. Svoboda (1995) achieved nitrogen removal ranging
from 47 to 70 percent (depending on aeration) through nitrification and denitrification in an
aerobic treatment reactor using whole pig slurry. The proportion of phosphorus and potassium
typically remaining after storage is higher than nitrogen. However, up to 80 percent of the
phosphorus in lagoons is found in the bottom sludge versus the water fraction (MWPS, 1993).
Jones and Button (1994) analyzed manure nutrient content just before land application in liquid
manure pit and anaerobic lagoon samples. On a mass basis for pit storage, nitrogen decreases
ranged from 11 to 47 percent; phosphorus, 9 to 67 percent; and potassium, 5 to 42 percent. In the
water fraction of lagoons, nitrogen decreases ranged from 76 to 84 percent; phosphorus, 78 to 92
percent; and potassium, 71 to 85 percent. Nitrogen decreases in these two storage systems were
primarily due to volatilization; phosphorus and potassium decreases were due to accumulation in
sludge. Boland et al. (1997) found that for deep pit systems almost four times as much land was
needed when applying manure based on phosphorus rather than nitrogen, 2.5 times for tank
storage, and 1.7 times for lagoon systems. These differences can be attributed to less ammonia
volatilization in deep pit systems and solids settling in lagoons.
A field study of Missouri swine lagoon surface-to-volume ratios found that large swine lagoons
have significantly higher total nitrogen concentrations than small lagoons. This finding suggests
that nutrient concentrations and thus land application of treated swine manure should be based on
the design and performance characteristics of the lagoon rather than on manure production alone
(Fulhage, 1998).
i
The use of evaporative lagoon systems has increased in arid regions. These systems rely on
evaporation to reduce wastewater with pollutants accumulating in the lagoon sludge. This
approach results in reduced or no land application of wastes. For example, due to a lack of
adequate land disposal area in Arizona, Blume and McCleve (1997) increased the evaporation of
wastewater from a 6,000-hog flush/lagoon treatment system by spraying the wastewater into the
6-2
-------
air. Although information on volatilization was not available, the evaporative increase from
spraying and pond evaporation versus pond evaporation alone was 51 percent.
The following sections characterize swine waste in terms of generation rates and chemical and
biological contaminants. Differences between swine types and operations and changes to the
waste after it leaves the pig are also characterized.
6.1.1 Quantity of Manure Generated
Table 6-1 shows the quantity of manure generated by different types of swine. Variation in these
quantities can be attributed to different ages and sizes of animals within a group (USDA, 1992).
Manure production can also vary depending on the digestibility of feed rations. For example,
corn, which is 90 percent digestible, results in less total solids in manure than a less digestible
feed such as barley, which is 70 percent digestible (USDA, 1992).
Table 6-1. Quantity of Manure Excreted by Different Types of Swine
Type of Swine
Grower-Finisher
Replacement Gilt
Boar
Gestating Sow
Lactating Sow
Sow and Litter
Nursery Pig
Manure Mass (lb/yr/1,000 Ib of animal mass)
Maximum
Reported
44,327"
29,872"
31,527"
18,250"
32,120"
21,900C
54.142"
Minimum
Reported
14,600"
ll,972"'b
7,483"
9,928"
21,900"-"
21,900°
23,981°
USDA 1998 Value
Grower-Finisher
29,380d
Farrow
12,220d
—
Farrow to Finish
38,940°
"NCSU, 1994.
"USDA,1992.
TVTWPS, 1993.
dUSDA,1998.
'Adapted from USDA, 1998.
— Not available.
As described in Chapter 3, there are three stages of swine production—farrow, nursery, and
grower-finisher. Some swine operations encompass all three stages, whereas otihers specialize in
just one. This section discusses the type of animal included in each operation and summarizes
data on the quantity of manure produced by different operations.
Farrowing Operations
Farrowing operations include boars, gestating sows, lactating sows, and the sows' litters.
Newborn pigs remain at the farrowing facility until they are weaned, which typically takes 3 to 4
weeks. Lactating sows and their litters produce the most manure, whereas boars produce the
least. Manure production values for 1,000 Ib of animal in a farrowing operation range from
7,483 (USDA, 1992) to 32,120 Ib/yr (NCSU, 1994), as shown in Table 6-2.
6-3
-------
Nursery Operations
After farrowing and weaning, young pigs are moved to a nursery, which is the second phase of
swine production, at approximately 15 pounds. They remain in the nursery for 7 to 8 weeks until
they weigh approximately 60 pounds and are then transferred to a grower-finisher operation.
Nursery pigs produce manure at rates of 23,981 (MWPS, 1993) to 54,142 lb/yr/1,000 Ib of
animal (NCSU, 1994) (Table 6-2).
Grower-Finisher Operations '
la a finishing operation pigs are raised to market weight, which is approximately 240 to 280
pounds. This third stage of swine production is typically 15 to 18 weeks long, after which
finished hogs are sent to market at approximately 26 weeks of age. A gro,wer-finisher operation
raises pigs over a relatively long period of tune, during which their weight changes substantially.
This weight change affects the quantity of manure produced (USDA, 1992). Values for manure
production from growing-finishing pigs range from 11,972 (USDA, 1992) to 44,327 lb/yr/1,000
Ib of annual (NCSU, 1994) (Table 6-2).
Farrow to Finish Operations . | . - .
A farrow to finish operation includes all three stages of swine production. Because of the large
variability in animal types present in this type of operation, manure production values vary
widely, from 7,483 lb/yr/1,000 Ib of animal forbears (USDA, 1992) to 54,142 lb/yr/1,000 Ib of
animal for nursery pigs (NCSU, 1994) (Table 6-1).
I
i
6.1.2 Description of Waste Constituents and Concentrations
Swine waste contains substantial amounts of nitrogen, phosphorus, potassium, and pathogens
and smaller amounts of other elements and Pharmaceuticals. This section provides a summary of
the constituents of swine waste as reported in the literature. There is significant variability in the
generation rates presented below; this variability can be attributed to different nutritional needs
for swine in the same operation type (sows and;boars, for example) and for swine of different
ages and sizes grouped in the same operation. Also, as shown earlier in Table 6-1, different types
of swine produce different quantities of manure.
Nitrogen . '
Nitrogen is usually measured as total nitrogen or as total Kjeldhal nitrogen (TKN). Although
TKN does not include nitrate-nitrogen (NO3-N), it may be considered equal to total nitrogen
because NO3-N is present only in very small quantities hi swine manure (0.051 to 1.241
lb/yr/1,000 Ib of animal) (NCSU, 1994; USDA, 1998). Published values for nitrogen production
range from 54.8 (USDA, 1992) to 228.8 lb/yr/1,000 Ib of animal (NCSU, 1994) in swine manure,
as shown in Table 6-2. In general, boars produce the least amount of nitrogen per thousand
pounds of animal and grower-finisher pigs produce the most.
6-4
-------
Table 6-2. Quantity of Nitrogen Present in Swine Manure as Excreted
Operation Type
Farrow to Finish
Grower-Finisher
Farrow
Nursery
Nitrogen (lb/yr/1,000 Ib of animal mass)
Maximum Reported
NA
228.8*
214.0"
224. la '
Minimum Reported
NA
87.6"
54.8°
134.0"
USDA 1998 Value
220.0C
166.0"
81.0a
—
•NCSU, 1994.
bUSDA,1992. '
cAdapted from USDA, 1998. •
*USDA, 1998.
Phosphorus
The quantity of phosphorus as excreted in swine manure is shown in Table 6-3 for different types
of swine operations. Phosphorus content ranges from 18.3 (USDA, 1992) to 168.2 lb/yr/1,000 Ib
of animal (NCSU, 1994)—boars excrete the least amount of phosphorus in manure per thousand
pounds of animal, whereas grower-finisher pigs excrete the most.
Table 6-3. Quantity of Phosphorus Present in Swine Manure as Excreted
Operation Type
Farrow to Finish
Grower-Finisher
Farrow
Nursery
Phosphorus (lb/yr/1,000 Ib of animal mass)
Maximum Reported
NA
168.2"
68.3"
93.4**
Minimum Reported
NA
29.2°
18.3°
54.6C
USDA 1998 Value
64.1"
48.3e
26.2°
—
TsTCSU, 1994.
"USDA, 1992.
•MWPS, 1993.
'Adapted from USDA, 1998.
TJSDA, 1998.
Potassium
Table 6-4 shows the range of measured potassium quantities in manure for each type of swine
operation. Boars produce the least amount of potassium at 36.50 lb/yr/1,000 Ib of animal
(USDA, 1992), whereas grower-finisher pigs produce the most at 177.4 lb/yr/1,000 Ib of animal
(NCSU, 1994).
6-5
-------
Table 6-4. Quantify of Potassium Present in Swine Manure as Excreted
Operation Type
Farrow to Finish
Grower-Finisher
Breeder
Nursery
Potassium (lb/yr/1,000 Ib of animal mass)
Maximum Reported i
NA i
177.4"
136.6" i
130.6" !
Minimum Reported
NA
47.45"
36.50"
103.88°
USDA 1998 Value
154.79"
116.79°
47.96e
—
"NCSU, 1994.
»USDA,1992. ' I •
-------
Table 6-5. Comparison of Nutrient Quantity in Manure for
Different Storage and Treatment Methods
Nutrient
Nitrogen
Phosphorus
Potassium
Mean Quantity in Manure (Ib/yr/1000 Ib of animal mass)
Paved
Surface
Scraped
Manure'
137.65
61.05
79.81
Liquid
Manure
Slurry"
164.44
. 51.28
78.20
Anaerobic
Lagoon
Liquid"
34.71
6.06
29.84
Anaerobic
Secondary
Lagoon
Liquid"
28.79
4.47
23.13
Anaerobic
Lagoon
Sludge"
6.57
6.18
1.46
Land-Applied Quantity
After Losses"
Farrow
20.29
22.12
43.01
Grower
17.23
17.11
43.75
"NCSU, 1994.
"USDA, 1998.
Table 6-6. Percent of Original Nutrient Content of Manure
Retained by Various Management Systems
Management System
Manure stored in open lot, cool humid region
Manure liquids and solids stored in an uncovered, essentially
watertight structure
Manure liquids and solids (diluted less than 50%) held hi waste
storage pond
Manure stored in pits beneath slatted floor
Manure treated in anaerobic lagoon or stored in waste storage
pond after being diluted more than 50%
Nitrogen
55-70
75-85
70-75
70-85
20-30
Phosphoru
s
65-80
85-95
80-90
90-95
35-50
Potassium
55-70
85-95
80-90
90-95
50-60
Source: Adapted from Jones and Sutton, 1994.
Table 6-7. Nutrient Concentrations for Manure in Pit Storage and
Anaerobic Lagoons for Different Types of Swine
Animal Type
Manure Produced
1000 gal/yr
Nitrogen
IbN/lOOOgal/yr
Phosphorus
Ib P/1000 gal/yr
Potassium
Ib K/1000 gal/yr
Pit Storage
Grower-Finisher
Lactating Sow
Gestating Sow
Nursery
0.53
1.4
0.5
0.13
32.75
15.00
25.00
25.00
11.55
5.25
13.55
8.44
22.41
9.13
22.41
18.26
Anaerobic Lagoon
Grower-Finisher
Lactating Sow
Gestating Sow
Nursery
0.95
2.10
0.90
0.22
5.60
4.10
4.40
5.00
1.639
0.874
1.857
1.398
3.486
1.660
3.320
2.656
Source: Adapted from Jones and Sutton, 1994.
6-7
-------
Metals and Other Elements
Other elements present in manure include the micronutrients calcium, chlorine, magnesium,
sodium, and sulfur, and heavy metals such as arsenic, cadmium, iron, lead, manganese, and
nickel. Many of these elements are found in swine feed; others, such as heavy metals, are found
in pharmaceutical feed additives. Table 6-8 shows the range of quantities of these elements in
manure as excreted, after storage, at different stages of treatment, and when it is land applied.
Table 6-8. Comparison of the Mean Quantity of Metals and Other Elements in
Manure for Different Storage and Treatment Methods
Element
Aluminum
Arsenic
Boron
Cadmium
Calcium
Chlorine
Cobalt
Copper
Chromium
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Selenium
Sodium
Sulfur
Zinc
Quantity produced in manure (lb/yr/1000 Ib animal mass)
As Excreted
1.340a
0.252s
1.132B-1.232a
0.010"-"
120.45b-121.468a
93.335a-94.9"
0.014"
0.437"-0.438b
—
5.84"-6.606a
0.030M).03r
25.55b-27.064a
0.640M).694°
O.OIO"-"
0.029a
—
23.980a-24.455b
27.192a-27.74"
1.825°-1.855a
Paved
Surface
Scraped
Manure'
0.797
—
0.239
0.001
117.932
90.615
0.013
0.960
—
16.858
0.019
33.766
4.573
0.001
0.048
—
24.536
24.791
2.414
Liquid
Manure
Slurry"
i 3.289
i 0.003
! 0.086
; 0.002
48.433
27.073
—
; 0.665
—
• 4.643
. —
16.884
i 0.790
—
0.016
•. —
18.148
; 14.702
2.210
Anaerobic
Lagoon
Liquid*
0.176
0.004
0.042
0.002
7.547
18.571
0.002
0.073
—
0.486
0.033
2.461
0.055
0.001
0.130
0.000
10.396
2.089
0.191
Anaerobic
Secondary
Lagoon
Liquid*
—
—
0.037
—
6.459
—
—
0.036
—
0.292
—
1.587
0.022
—
—
—
—
1.542
0.036
Anaerobic
Lagoon
Sludge*
—
—
0.004
0.001
6.373
0.378
—
0.082
0.007
0.713
0.007
1.837
0.082
0.003
0.003
—
0.536
1.333
0.212
•NCSU, 1994.
'ASAE, 1998. i
Swine manure contains many kinds of bacteria.; several of which are naturally present in the
digestive systems of the animals. Others are in the pigs' general environment and can be
ingested but are not a necessary component of digestion. Table 6-9 presents a summary of
measured values of these bacteria in swine manure as excreted and at various stages of treatment.
6-B
-------
Table 6-9. Comparison of the Mean Concentration of Pathogens in
Manure for Different Storage and Treatment Methods
Type of Bacteria
Enterococcus bacteria
Eschenchia coliform bacteria
Facultative bacteria
Fecal coliform bacteria
Fecal streptococcus bacteria
Streptococcus bacteria
Total aerobic bacteria
Total anaerobic bacteria
Total bacteria
Total coliform bacteria
Quantity Present in Manure (bacterial colonies per pound of manure)
Manure As
Excreted
3.128E+09
4.500E+07
—
1.106E+09
2.873E+10
1.980E+08
—
—
—
2.445E-K»9
Paved
Surface
.Scraped
Manure
1.395E+09
5.400E+07
5.400E+11
4.800E+08
—
2.205E+10
2.745E+11
5.400E+11
—
1.598E+09
Liquid
Manure
Slurry
3.839E+09
1.302E+08
5.164E+11
1.777E+07
2.276E+07
1.995E+10
1.269E+11
1.092E+11
—
9.551E+07
Anaerobic
Lagoon
Liquid
1.232E+06
—
—
2.502E+06
2.285E+06
—
—
—
3.885E+08
1.083E+07
Anaerobic
Lagoon
Sludge
—
—
- —
— -
—
—
—
—
7.769E+09
• HIM
Source: NCSU, 1994.
Pharmaceuticals
To promote growth and to control the spread of disease, antibiotics and other pharmaceutical
agents are often added to feed rations. Many of these chemicals are transformed or broken down
through digestion and then- components are excreted in manure. Table 6-10 lists several
common Pharmaceuticals added to swine feed and their frequency of use as reported in Swine '95
Part I: Reference of 1995 Swine Management Practices (USDA APHIS, 1995).
Table 6-10. Type of Pharmaceutical Agents Administered in Feed, Percent of
Operations that Administer them, and Average Total Days Used
Antibiotic/Agent in Feed
Chlortetracycline/Sulfathiazole/Penicillin
Chlorotetracyeline/Sulfamethazine/Penicillin
Tylosin/Sulfamethazine .
Carbadox
Lincomycin
Apfamycin
Chlortetracycline
Oxytetracycline
Neomycin/Oxytetracycline
Tylosin
Bacitracin (BMD)
Virgimamycin
Zinc oxide
Copper sulfate
Other
Percent
Operations
6.7
6.4
4.8
12.4
4.3
2.8
41.1
9.6
10.4
30.4
52.1
3.8
5.0
6.1
4.6
Standard
Error
2.1
2.0
2.1
2.5
1.4
1.2
4.0
2.2
3.0
3.7
4.1
1.3
2.1
1.9
2.2
Average
Total
Number
Days
33.8
23.6
45.6
31.2
60.3
50.9
58.1
39.2
55.3
57.4
72.2
65.1
81.2
62.8
. 97.6
Standard
Error
5.3
3.6
4.1
2.1
17.6
22.7
4.6
6.6
14.6
5.1
4.0
11.6
22.9
11.3
11.8
Source: USDA APHIS, 1995.
6-9
-------
Physical Characteristics
Tables 6-11 and 6-12 lists several characteristics of swine manure as excreted by pigs classified
by different operation types and with different types of storage and treatment methods.
Table 6-11. Physical Characteristics of Swine Manure by
Operation Type and Lagoon System
Characteristic
Manure
Urine
Density
Qb/fl?)
Moisture
(%)
Total solids
Total
dissolved
solids
Volatile
solids
Fixed solids
C:N ratio
Ph
Grower-
Finisher as
Excreted
11,972"-
33,830"
42.1b-49.0b
61.8b-62.8b
90a-91a
3.28a-6.34a
1.29"
2.92a-5.40a
0.36a-0.94a
6a-7a
rcical Characteristics in Swine Manure (lb/yr/1000 Ib unless otherwise noted)
Farrow as
Excreted
7,483a-
27,313"
—
—
90a-97a
1.9"-6.0a
—
l.OQ-5.40
0.30a-0.60a
3a-6a
Farrow to
Finish as
Excreted •
7,483a-!
39,586"?
39.00-74.0B
61.3-62.8
90a-97a
1.9a-11.0a
1
1.29a |
1.00-8.80
0.30a-1.80a
3a-8a
Liquid
Manure
Slurry"
6,205
• —
8.4 .
—
. —
—
—
—
' —
Anaerobic
Lagoon
Sludge"
270
—
8.9
92a
7.60%°
—
379.89 c
Ib/lOOOgal
253.27°
lb/1000 gal
8a
Anaerobic
Lagoon
Liquid"
7,381
—
8.4
100"
0.25%c
—
10.00°
lb/1000 gal
10.83 °
lb/1000 gal
— •
Anaerobic
Secondary
Lagoon
Liquid"
7,381 '
—
8.35
—
--
—
_.
—
2*
•USDA, 1992.
"NCSU, 1994.
'USDA, 1996.
Table 6-12. Physical Characteristics of Different Types of Swine Wastes
Physical
Characteristic
Manure
Density Ob/ft3)
Moisture (%)
Total solids
lb/yr/1000 Ib
Paved Surface Scraped
Manure*
21,089
62.4
. —
—
Ib/ 1000 gallons
Feedlot Runoff Water"
—
—
98.50
1.50
Settling Basin Sludge"
—
—
88.8
11.2
ANCSU, 1994
'USDA, 1996
6.2 Poultry Waste
I
Poultry wastes differ in composition between the three bird types addressed in this document -
layers, broilers, and turkeys. Each bird type is raised for a specific role and is provided with a
diet tailored to its nutritional needs. Hence, layers are fed diets to maximize egg production
6-10
-------
whereas broilers are fed diets to promote growth and development. Within each subsector,
however, variation in manure composition as excreted is quite small due to the high degree' of
integration, use of standardized feed, and total confinement (USEPA, 1999). However, there are
differences in composition and quantity generated between operations due to variations in length
and type of manure storage employed by the operation.
Broilers and turkeys have similar production regimes in terms of manure production, manure
handling, and nutrient recovery. The floor of the house is covered with a bedding material that
absorbs liquid. During the growth of the flock, continuous air flow removes ammonia and other
gasses resulting in lower nitrogen content of the litter (manure and bedding). Another result of
continuous air flow is a reduction in the moisture content of the litter over that of freshly excreted
manure. .
Manure produced by the laying industry typically includes no bedding. Two main types of
manure handling are handling as excreted manure (with no bedding) and water-flushed
collection. In high-rise cages or scrape-out/belt systems, manure is excreted onto the floor below
with no bedding to absorb moisture. The ventilation system dries the manure as it is stored.
Nutrients are more concentrated without bedding than with bedding, as in the broiler and turkey
manure handling procedures. Flushing layer manure with water results in diluted nutrient
concentrations, but increases the amount of waste that must be disposed.
As shown in Table 6-13, manure generation rates differ considerably between layers and broilers.
The maximum reported generation rate for broilers is over 30 percent greater than for layers.
Pullets have the lowest generation rate- almost half the rate of manure production for broilers and
only 70 percent of the production rate for layers.
6.2.1 Broiler Waste Characteristics
6.2.1.1 Quantity of Manure Generated
Manure production is frequently presented as volume or weight of manure produced per 1,000
pounds of animal mass. There is significant variation between the minimum and maximum
reported values for manure generation in broilers. Table 6-13 contains the minimum, maximum,
and 1998 USDA reported values for manure generation rates for broilers. The 1998 USDA
reported value for manure generation was utilized ha EPA's analyses.
Table 6-13. Quantify of Manure Excreted for Broilers
Minimum Reported
Manure Mass (lb/yr/1,000 Ib of animal mass)
Maximum Reported
31.025b
USDA 1998 Value
29,940°
"ASAE, 1998.
TJSDA, 1998.
6-11
-------
6.2.1.2 Description of'Waste Constituents and Concentrations
Broiler waste contains nitrogen, phosphorus, potassium, and smaller amounts of other elements
and pathogens. This section provides a summary of the constituents of broiler manure and litter .
as reported in the literature. '
Table 6-14 shows selected physical and chemical characteristics for broiler manure as excreted
and after application of different storage practices. Manure quantity decreases under dry storage
practices, especially when stored as a manure cake.
Table 6-14. Consistency of Broiler Manure as Excreted and for Different Storage Methods
Physical
Characteristic
Manure/Litter
Density
Moisture
Total solids
Volatile solids
Fixed solids
C:N ratio
Physical Characteristics of Manure (lb/yr/1,000 Ib of animal mass unless otherwise
noted)
As Excreted
25,550a-3 1,025"
63&-63.T
75"
7,300a-8,030D
5,475d-8,030*
1,825"
8J
Broiler
Litter"
12,775
—
24
9,673
7,811
1862
9
! Broiler
House
Litter0
, 7,449
31.7
—
5,857
: 4,666
—
—
Broiler
House
Manure
Cakec
2,364
34.3
—
1,429
1,110
—
—
Broiler
Litter
Stockpile0
6,733
33.1
—
4,083
2,903
—
—
Broiler-
Roaster
House
Litter0
5,710
29.0
—
4,349
3,349
—
. —
•ASAE, 1998.
'MWPS, 1993.
-------
Table 6-15. Nutrient Quantity in Broiler Manure as Excreted
Nutrient
Nitrogen
Phosphorus
Potassium
Quantity Present in Manure (Ib/yr/1,000 Ib of animal mass)
Minimum Reported
310.25*
71.68"
139.27"
Maximum Reported
401.50biC
124.10°
167.90"
Time-Averaged Value
401.65°
116.77e
157.04=
"USDA, 1992.
CASAE, 1998.
•"NCSU, 1994.
"USDA, 1998.
Table 6-16. Broiler Liquid Manure Produced and Nutrient
Concentrations for Different Storage Methods
Storage Method
Raw Manure
Pit Storage2
Anaerobic Lagoon Storage "
Manure Produced
(1000 gal/yr)
0.006
0.010
0.016
Nutrient Concentration (Ib nutrient/1000 gal)
Nitrogen
130.4
63.00
8.50
Phosphorus
36.3
17.48
1.88
Potassium
44.3
24.07
2.91
Source: MWPS, 1993 as presented by Jones and Sutton, 1994,
* Includes dilution water.
b Includes rainfall and dilution water.
Table 6-17. Nutrient Quantity in Broiler Litter for Different Storage Methods
Nutrient
Nitrogen
Phosphorus
Potassium
Quantity Present in Manure and Litter (lb/yr/1,000 Ib of animal mass)
Broiler Litter"
248.20
124.10
146.00
Broiler House
Litter11
26.59
112.70
144.06
Broiler House
Manure Cakeb
53.80
27.18
35.37
Broiler Litter
Stockpile"
109.87
112.70
89.52
Broiler-
Roaster House
Litterb
196.71
87.09
110.67
"•NRCS, 1994.
6-13
-------
Table 6-18. Quantity of Metals and Other Elements Present in Broiler
Manure as Excreted and for Different Storage Methods
Element
Aluminum
Arsenic
Barium
Boron
Cadmium
Calcium
Chlorine
Cobalt
Copper
Chromium
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Selenium
Silicon
Sodium
Strontium
Sulfur
Zinc
Quantity Present in Manure and Litter (lb/yr/1,000 Ib of animal mass)
As Excreted
—
—
—
0.795"
0.017a
136.626a-149.650l>
296.537"
—
0.331a-0.358"
—
29.509"
0.033"
50.336"-54.750b
2.378"
—
0.134"
0.111"
—
—
50.336"-54.750"
—
28.763a-31.025b
1.208a-1.314"
Broiler House
Litter"
4.901
0.176 :
0.148
0.211
0.012
158.424
47.694
0.007
1.984
0.566
4.381
0.151
32.871 :
2.957
0.001
0.003
0.427
0.002
5.323 '
48.668
0.339
45.749
2.652
Broiler House
Manure Cake"
—
—
• —
0.052
0.002
40.197
—
—
0.481
0.185
1.420
0.054
8.225
0.815
—
0.001
0.217
—
—
12.390
—
10.876
0.713
Broiler Litter
Stockpile"
—
—
—
0.131
0.001
212.888
51.803
—
0.968
0.006
5.991
—
27.596
2.344
—
0.002
0.008
—
—
22.290
—
33.892
2.112
Broiler-
Roaster House
Litter"
—
—
. —
0.133
0.014
117.184
—
—
1.389
0.942
4.553
0.204
24.04-6
2.170
—
0.002
0.352
—
• —
37.143
—
39.22,9
1.932
•NCSU, 1994.
VASAE, 1998.
Microbial populations are very active in broiler litter and include enterococcus, fecal conform,
salmonella, and streptococcus. Table 6-19 shows bacteria levels per pound of manure.
Table 6-19. Concentration of Bacteria in Broiler House Litter
Parameter
Total bacteria
Total coliform bacteria
Fecal coliform bacteria
Streptococcus bacteria
Salmonella
Total aerobic bacteria
Concentration of Bacteria
(bacteria colonies/lb manure)
4.775E+11
2.285E+06
7.758E+06
6.728E+09
2.048E+06
7.107E+09
Source: NCSU, 1994.
,6-14
-------
6.2.2 Layer Waste Characteristics
6.2.2.1 Quantity of Manure Generated
Manure production is frequently presented as volume or weight of manure produced per 1,000
pounds of animal mass. There is less variation between the minimum and maximum reported
values for manure generation in layers than for broilers. Table 6-20 contains the minimum,
maximum, and 1998 USDA reported values for manure generation rates for layers. The 1998
USDA reported value for manure generation was utilized in EPA's analyses.
Table 6-20. Quantity of Manure Excreted for Layers
Minimum Reported
Manure Mass (lb/yr/1,000 Ib of animal mass)
19.163"
Maximum Reported
23.722°
USDA 1998 Value
22.900C
"NCSU, 1994.
•USDA, 1998. .
6.2.2.2 Description of Waste Constituents and Concentrations
Layer waste contains nitrogen, phosphorus, potassium, and smaller amounts of other elements
and pathogens. This section provides a summary of the constituents of layer manure as reported
in the literature. Table 6-21 shows selected physical and chemical characteristics for layer
manure as excreted and after application of different storage and treatment practices. Manure
quantity decreases under dry storage practices but increases significantly when converted to a
slurry or stored and treated in an anaerobic lagoon.
6-15
-------
Table 6-21. Physical Characteristics of Layer Manure as
Excreted and for Different Storage Methods
Physical
Characteristic
Manure
Density (Ib/ft3)
Moisture (%)
Total solids
Total
suspended •
solids
Volatile solids
Volatile
suspended
solids
Fixed solids
C:N ratio
Physical Characteristics of Manure (lb/yr/1,000 Ib of animal mass unless otherwise noted)
As Excreted
19,163a-23,722b
60.0^-65.1"
74.8a-75.0a
5,512a-6,019°
2,477"
3,942"-4,440"
4810-4,380C
1,570"
7"
High-
rise
Litter*
14126
62.4
—
4979
3483
—
—
Paved
Surface
Scraped
Manure1"
9877
51.3
i. —
5216
i
3137
—
—
Unpaved
Deep Pit
Stored
Manure6
32534
7.8
• —
3646
748
2401
637
—
—
Liquid
Manure
Slurry"
53598
8.4
—
265
101
119
52
—
—
Anaerobic
Lagoon
Liguidb
9881
8.4
—
1633
722
—
—
Anaerobic
Lagoon
Sludge"
98805
8.4
—
1633
722
—
1 —
•MWPS, 1993.
*NCSU,1994. :
'ASAE.1998. i
*USDA, 1992.
Layers excrete numerous nutrients including nitrogen, phosphorous, and potassium. As shown in
Table 6-22, nitrogen is excreted at the highest rate of these three nutrients. Nutrient
concentrations of liquid manure are shown in Table 6-23. Table 6-24 shows nutrient production
after application of storage and/or treatment practices. Table 6-25 shows metals in layer manure
as excreted and for different storage and treatment methods.
Table 6-22. Quantity of Nutrients in Layer Manure as Excreted ,
Nutrient
Nitrogen
Phosphorus
Potassium
Quantity Present in Manure (lb/yr/1,000 ib of animal mass)
Minimum Reported
264.63a
99.55a
106.05"
Maximum Reported
315.43°
113.15°
124. 10C
Tune-Averaged Value
308.35°
114.27"
119.54"
•MWPS, 1993.
'NCSU, 1994.
*USDA, 1998.
6-16
-------
Table 6-23. Annual Volumes of Liquid Layer Manure
Produced and Nutrient Concentrations
Storage Method
Raw Manure
Pit Storage a
Anaerobic Lagoorl Storage b
Manure Produced
(lOOOgal/yr)
0.011
0.017
0.027
Nutrient Ob nutrient/1000 gal )
Nitrogen
110.2
60.00
7.00
Phosphorus
35.4
19.67
1.75
Potassium
37.7
23.24
2.91
Source: MWPS, 1993 as presented by Jones and Sutton, 1994.
* Includes dilution water.
b Includes rainfall and dilution water.
Table 6-24. Nutrient Quantity in Layer Litter for Different Storage Methods
Nutrient
Nitrogen
Phosphorus
Potassium
Quantity Present in Manure and Litter (lb/yr/1,000 Ib of animal mass)
High-rise
Litter"
199.44
97.60
114.40
Paved
Surface
Scraped
Manure1"
165.79
110.21
107.96
Unpaved
Deep Pit
Stored
Manureb
238.42
94.55
114.40
Liquid
Manure
Slurryb
42.35
4.77
54.75
Anaerobic
Lagoon
Liquid"
24.63
39.87
9.60
Anaerobic
Lagoon
Sludge"
24.63
39.87
9.60
"USDA, 1992.
*NCSU, 1994.
Table 6-25. Quantity of Metals and Other Elements Present in
Layer Manure as Excreted and for Different Storage Methods
Element
Aluminum
Arsenic
Boron
Cadmium
Calcium
Chlorine
Cobalt
Copper
Chromium
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Selenium
Sodium
Sulfur
Zinc
Quantity Present in Manure and Litter (lb/yr/1
As Excreted
9.987"
0.050"
0.651"-0.6570
0.014"-"
474.5008-491.891a
204.400"-242.608*
0.029"
0.303"-0.308a
—
21.900"-24.143a
0.2706-0.274a
51.100"-51.129"
1.945a-2.227"
—
0.109"-0.110"
0.09 1"-"
0.010"
36.500"-43.292"
51.053"-51.100D
1.640a-6.935B
High-rise
Litter"
2.161
—
0.157
0.001
288.598
28.394
•
0.244
0.114
2.936
0.135
58.577
2.032
—
0.002
0.351
—
19.646
49.971
2.162
Paved
Surface
Scraped
Manure*
—
—
0.178
—
375.753
—
—
0.285
0.188
14.008
0.656
28.306
2.165
—
0.002
0.418
—
16.268
23.554
1.721
Unpaved
Deep Pit
Stored
Manure*
4.039
—
0.125
—
138.050
27.554
—
0.302
—
7.089
—
. 16.495
1.579
—
—
—
—
20.082
16.762
1.609
000 Ib of animal mass)
Liquid
Manure
Slurry*
—
0.002
0.059
0.000
6.945
21.777
—
0.030
0.002
0.387
0.005
2.188
0.044
0.000
—
0.075
—
11.755
3.918
0.100
Anaerobic
Lagoon
Liquid*
—
—
0.041
0.007
55.653
— .
—
0.167
—
5.727
0.023
13.629
1.896
—
—
0.029
—
3.958
8.414
1.346
Anaerobic
Lagoon
Sludge*
—
—
0.041
0.007
55.653
—
—
0.167
—
5.727
0.023
13.629
1.896
—
—
0.029
—
3.958
8.414
1.346
•NCSU, 1994.
bASAE, 1998.
TJSDA, 1992.
6-17
-------
Microbial populations are quite active in layer litter and include enterococcus, fecal colifonn,
salmonella, and streptococcus. Table 6-26 shows bacteria levels per pound of manure. As
shown in this table, converting the litter to a slurry substantially reduces the concentration of
bacteria. :
Table 6-26. Concentration of Bacteria in Layer Litter
Type of Bacteria
Enterococcus bacteria
Fecal colifonn bacteria
Fecal streptococcus bacteria
Salmonella
Streptococcus bacteria
Total aerobic bacteria
Total bacteria
Total colifonn bacteria
Yeast
Concentration in Manure (bacterial colonies/lb manure)
As Excreted
2.786E+13
1.552E+13
3.375E+13
1.327E+10
6.237E+13
8.568E+15
9.716E+16
1.835E+14
1.327E+15
Layer Liquid Manure Slurry
—
1.058E+06
—
—
—
—
—
7.547E+06
Source: NCSU, 1994. .
6.2.3 Turkey Waste Characteristics
Turkey operations usually separate and handle the birds in groups according to age, gender, size,
or special management needs such as hatcheries or breeder farms. The types of animals are
• Poults (young turkeys)
• Turkey hens for slaughter
• Turkey toms for slaughter
• Hens kept for breeding
Although three major strains of turkeys are grown, the high degree of industry integration,
standardized feed, and complete confinement has resulted in very little variation in manure
characteristics. The exact quantity and composition of manure depends mostly on the specifics
of farm management, such as precision feeding, control of wasted feed, and ammonia
volatilization losses. Litter characteristics also vary according to material used for bedding.
6.2.3.1 Quantity of Manure Generated
Manure production is frequently presented as volume or weight of manure produced per 1,000
pounds of animal mass. Table 6-27 shows manure production as excreted for turkey hens and
turkeys for slaughter.
6-18
-------
Table 6-27. Annual Fresh Excreted Manure Production (lb/yr/1,000 Ib of animal mass)
Animal Type
Turkeys for slaughter
Hens for breeding
Range of Annual Manure Production Values
15,914"-17,155b
USDA 1998 Value
16,360C
18,240"
bASAE, 1998.
6.2.3.2 Description of Waste Constituents and Concentrations
Turkey waste contains-nitrogen, phosphorus, potassium, and smaller amounts of other elements
and pathogens. This section provides a summary of the constituents of turkey manure and litter
as reported in the literature.
Composition of Manure
Exact manure composition depends on length and type of storage, as well as other management
practices specific to each farm. Table 6-28 shows nutrients-in turkey manure as excreted.
Turkeys for slaughter produce more nitrogen and potassium in fresh excreted manure and
breeding hens produce more phosphorus. •
Table 6-28. Quantity of Nutrients Present in Fresh Excreted
Turkey Manure (lb/yr/1,000 Ib of animal mass)
Animal Type
Turkeys for
slaughter
Hens for
breeding
Nitr
Range
Includes
Minimum
248.34"
204.38"
»2en
Maximum
Reoorted
270.1b
Phosphorus
Minimum
Reported
84°
Range
Includes
•96.77"
120.48"
Potassium
Range
Includes
94.97"
69.31"
Maximum
102.20"
•USDA, 1998.
'USDA, 1992.
CASAE, 1998.
Composition of Litter
The nutrient content of turkey litter is usually lower than that for broiler litter, and brooder litter
contains less manure nutrients than grower house litter. Exact manure composition depends on
length and type of storage, as well as other management practices specific to each farm. After
stockpiling, Utter may lose up to half of the total nitrogen excreted. When manure is combined
with bedding materials, the waste litter absorbs water content from the manure. Table 6-29
displays the water absorption capacity of commonly used bedding materials. Because of
different types of litter composition for turkey operations, nutrient quantities per ton of litter vary
(Table 6-30).
6-19
-------
Table 6-29. Water Absorption of Bedding
Bedding Material !
Wood
Tanning Bark i
Fine Baric
Pine . 1
Chips . :
Sawdust
Shavings
Needles
Hardwood Chips, Shavings or Sawdust
Corn
Shredded Stover
Ground Cobs ;
Straw
Flax
Oats
Combined
Chopped
Wheat
Combined
Chopped
Hay, Chopped Mature
Sltells. Hulls
Cocoa
Peanut, Cottonseed
Oats
Pounds of Water Absorbed per Pound of Bedding
4.00
2.50
3.00
2.50
2.00
1.00
1.50
2.50
2.10
2.60
2.50
2.40
2.20
2.10
3.00
2.70
2.50
2.00
Source: MWRA, 1993.
Table 6-30. Turkey Litter Composition in pounds per ton of litter3
Manure Type
Brooder house litter after each flockb
Grower house litter after annual cleanout "
Stockpiled litter"
Tom grpwoutc
Hen growout0
Brood house"
Growout house"
Nitrogen
45
57
36
52
73
51
65
Phosphorus
23
31
30e-31
33
38
14
28e-31
Potassium
27
33
25°-27
35
38
27
33e-38
•Zublena, 1993
^080,1999 :
•Pennsylvania
'Arkansas
•NCSU.1994. ,
PjOj converted to P by multiplication of 0.437
KjO converted to P by multiplication of 0.83
In those cases where litter is recycled from the brooder barn and used in the growout barn,
nutrient values of litter increase to roughly 60 pounds of available nitrogen and phosphorus per
ton of litter. Table 6-31 presents some metal components of turkey litter.
6-20
-------
Table 6-31. Metal Concentrations in Turkey Litter (pounds per ton of litter)
Turkey,
brooder
Ca
28.0
42.0
Me
5.7
7.0
S
7.6
10.0
Na
5.9
8.4
Fe
1.4
1.3
Mn
0.52
0.65
B
0.047
0.048
Mo
0.00081
0.00092
source: NCSU, 1999. "
Zn
0.46
0.64
Cu
0.36
0.51
The physical characteristics and nutrient content of turkey manure types and litter types is
variable. As seen in Table 6-32, manure characteristics significantly differ from litter
characteristics. Fresh manure contains more nutrients than manure cakes, but litter from grower
houses may exceed fresh manure potassium amounts. Table 6-33 shows metal quantities in
excreted turkey manure and litter types by gender and age of bird.
Table 6-32. Waste Characterization of Turkey Manure
Types (lb/yr/1,000 Ib of animal mass)
Parameter
Manure
Litter
(ff/yr/lOOO Ib)
DensiryOb/ff)
TKN
NO3N
P
K
Turkey fresh
manure
15,914C-
J7,155d
251.85°.
63d-63.49a
4,179a-4,380"
3,205a-3,541c
226.3°-231.0a
84.0d-87.8a
83.2a-87.6"
Turkey hen
house
manure cake*
1905.3
—
—
32.3
1041.6
845.2
42.74
-
19.38
23.69
Turkey torn
house
manure cake*
1905.3
—
—
—
1041.6
. 845.3
42.74
-
19.38
23.69
Turkey house
Utter*
_.
5960.5
—
4365.4
3182.8
165.13
0.40
82.38
98.77
Turkey poult
(brooder)
_
6953.25
—
22.91
5527.96
4297.07
138.12
1.31
65.77
77.64
•NCSU, 1994.
Turkey
breeder
—
4967.65
—
62.43
3893.35
87.97
51.17
37.05
Turkey
' stockpiled
litter*
_
5420.25
—
24.1 •
3316.90
85.67
1.31
82.42
67.74
"USDA,1998.
CUSDA,1992.
dASAE, 1998.
6-21
-------
Table 6-33. Metals and Other Elements Present in Manure (lb/yr/1,000 Ib of animal mass)
Petals/Elements
Calcium
Magnesium-
Sulfur
Sodium
Chlorine
Iron
Manganese
Boron
Molybdenum
Aluminum
Zinc
Copper
Cadmium
Nickel
Lead
Turkey
fresh
manure
223.205"-
230.0" •
25.649"-
26.6"
25.887"
23.172"-
24.0b
16.8407"
26.556"-
27.4b
O.SSSMW
0.452"
0.076"
—
5.127"-5.5b
0.252"-0.3b
0.009"
0.063"
0.190"
Turkey hen
house
manure
cake"
25.003
5.11
5.986
5.256
—
1.168
0.548
0.037
0.001
0.694
0.438
0.475
—
' —
—
Turkey torn
house
manure
cake*
25.003
5.11
5.986
5.256
— .
1.168
0.5475
0.0365
0.001
0.694
0.438
0.475
—
—
—
Turkey
house
Utter"
112.165
22.083
25.477
22.703
35.186
4.176
2.3725
0.146
0.004
2.263
1.971
1.789
0.001
0.018
—
Turkey poult
(brooder)
house litter"
91.871
17.849
21.207
162.06
6.278
6.935
1.825
0.146
0.003
5.037
1.606
1.351
0.001
0.007
—
Turkey
breeder
house
litter"
178.376
11.498
18.287
10.622
—
2.519
1.059
0.073
, —
—
1.241
0.986
—
—
—
Turkey
stockpiled
litter"
120.888
19.199
20.039
15.367
21.608
5.585
2.044
0.110
0.003
—
1.716
1.132
0.001
0.007
—
•NCSU, 1994.
Data on bacterial concentrations in turkey manure or litter are generally sparse. However, Table
6-34 shows concentrations of fecal coliform and total bacteria for manure and litter. Land
applied quantities of turkey manure nutrients are shown in Table 6-35.
Table 6-34. Turkey Manure and Litter Bacterial Concentrations
(bacterial colonies per pound of manure)
Bacteria Type
Fecal coliform bacteria
Total bacteria
Excreted Manure
1.31E+08
i ^_
House Litter
—
2.53E+12
Source: NCSU, 1994.
Table 6-35. Turkey Manure Nutrient Composition After Losses-Land Applied Quantities
Animal
Turkeys for slaughter
Hens for breeding
Manure Composition (lb/yr/1,000 Ib of animal mass)
Nitrogen
132.35(116.0)
102.14 (102.2)
Phosphorus
82.29 (14.5)
102.42(18.1)
Potassium
85.40 (9.6)
62.38(6.9)
Source: USDA, 1998.
In parentheses are the differences between fresh excreted manure content and after losses content.
6-22
-------
6.3 Dairy Waste
This section describes the characteristics of dairy manure and waste. In this section, manure
refers to the combination of feces and urine and waste refers to manure plus other material, such
as hair, bedding, soil, wasted feed, and water that is wasted or used for sanitary and flushing
purpose. Due to the nature of dairy operations, however, even fresh manure may also contain
small amounts of hair, bedding, soil, feed, and water.
This section discusses the following:
Section 6.3.1: The quantity of manure generated; and
• Section 6.3.2: Description of waste constituents and concentrations.
6.3.1 Quantity of Manure Generated
Numerous analyses have estimated average manure quantities from dairy cattle. Four major data
sources that contain mean values for dairy manure characteristics are identified below:
American Society of Agricultural Engineers (ASAE) Standard D384.1: Manure
Production and Characteristics, 1999. This data source contains national fresh
(as-excreted) manure characteristic values by animal type (e.g., dairy, beef, veal, swine).
USDA, Agricultural Waste Management Field Handbook, Chapter 4,1996. This data
source contains national manure characteristic values for fresh and managed manure (e.g.,
lagoon supernatant, feedlot runoff) by animal type including subtypes such as lactating
cow, dry cow, heifer, sow, and boar.
North Carolina State University (NCSU), Livestock Manure Production and
Characterization in North Carolina, 1994. This data source contains regional manure
characteristic values for fresh and managed manure by animal type including subtypes.
Midwest Plan Service-18 (MWPS): Livestock Waste Facilities Handbook, 1985. This
data source contains national fresh manure characteristic values by animal type and
animal weight.
A recent analysis conducted by Charles Lander, et al. of the USDA/NRCS used a composite of
three of these data sources (Lander et al., 1998). Lander removed ASAE data before averaging to
prevent double counting of the ASAE information that is included in the Midwest Plan Service
data. This analysis assumed that the average weight of a lactating cow is 1,350 pounds and the
average weight of a heifer is 550 pounds. Table 6-36 presents the fresh or "as-excreted" manure •
estimates from this analysis. North Carolina's updated data contains the as-excreted manure
estimates for dairy calves which are assumed to weigh 350 pounds. Table 6-36 also presents the'
fresh manure estimates for dairy calves.
6-23
-------
Table 6-36. Weight of Dairy Manure, "As-Excreted"
Quantity of Manure (wet basis)
Weight (Ib/day/l.OOO-lb animal)
Weight (lb/year/l,000-lb animal)
Lactating Cow*
83.5 .
30,478
Heifer"
66
24,090
Calf*
65.8
24,017
•Source: Lander, 1998.
b Source: NCSU, 1994.
63.2 Description of Waste Constituents and Concentrations
The composition and concentrations of dairy waste varies from the time that it is excreted to the
time it is ultimately used as a fertilizer and/or soil amendment. Nutrients and metals are
expected to be present in dairy waste due to the constituents of the feed. This section discusses
the following:
• Section 6.3.2.1: Composition of "as-excreted" manure;
• Section 6.3.2.2: Composition of stored or managed waste; and ,
• Section 6.3.2.3: Composition of aged manure/waste.
i
63.2.1 Composition of "As-Excreted" Manure
Data are presented for 16 nutrients and metals found in fresh dairy manure. Nitrogen is present
in'manure in four forms: ammonium-N, nitrate-N, nitrite-N, and 6rganic-N. The total nitrogen
(N) is the sum of these four components, while the total Kjeldahl nitrogen (TKN) is the sum of
the organic-N and ammonium-N. Phosphorus is present in manure in inorganic and organic form
and presented as total phosphorus. Colonies of the pathogens coliform and streptococcus
bacteria have also been identified in dairy manure.
Manure characteristics for dairy cattle are highly variable and can be affected by animal size and
age, management choices, feed ration, climate, and milk production. For example, dairy feeding
systems and equipment often produce considerable feed waiste, which in most cases is added to
the manure. In addition, dairy stall floors are often covered with organic and inorganic bedding
materials (e.g,. hay, straw, wood shavings, sawdust, soil, sand, ground limestone, dried manure)
that improve animal comfort and cleanliness. Virtually all of this material will eventually be
pushed, kicked, and carried from the stalls and added to the manure, and their characteristics
imparted to the manure (Lander et al., 1998). In addition, the nutrient content (N, P, and K) of
dairy manure can vary significantly due to differences hi voluntary feed intake, differing
supplemental levels, and differing amounts of nutrients removed during milking (USD A NRCS,
1992). The volatile solids content of dairy manure is often compared to milk production, which
is also presented in USDA, Agricultural Waste Management Field Handbook, Chapter 4, 1996.
The volatile solids content of manure for an entire dairy herd can be calculated by using data for
lactating and dry cows. For example, EPA's analysis assumed the dairy herd is made up of 83
percent lactating and 17 percent dry cows at any given time. The volatile solids content for the
6-24
-------
dairy herd, using USDA data, therefore, was calculated as (8.5 lb/day/1,000 animal * 83 percent)
+ (8.1 lb/day/1,000 animal * 17 percent) = 8.45 lb/day/1,000 animal.
Table 6-37 presents averages for fresh dairy cow and heifer manure characteristics that are
reported in the four major data sources identified above.
Table 6-37. Fresh (As-Excreted) Dairy Manure Characteristics
Per 1,000 Pounds Live Weight Per Day
Parameter
Moisture
Weight
Total solids
Volatile solids
Biochemical oxygen demand (BOD), 5-day
Chemical oxygen demand (COD)
PH
Nitrogen (Total Kjeldahl)
Nitrogen (Ammonia)
Phosphorus (Total)
Orthophosphorus
Potassium
Calcium
Magnesium
Sulfur
Sodium
Chloride
Iron
Manganese
Boron
Molybdenum . ' .
Zinc
Copper
Cadmium
Nickel
Total coliform bacteria
Fecal coliform bacteria
Fecal streptococcus bacteria
Unif
%
Ib
Ib
Ib
Ib
Ib
unitless
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
colonies
colonies
colonies
Mean
87.2
86
12
10
1.6
11
7
0.45
0.079
0.094
0.061
0.29
0.16
0.071
0.051
0.052
0.13
0.012
0.0019
0.00071
0.000074
0.0018
0.00045
0.0000030
0.00028
500
7.2
42
Standard Deviation
-
17
2.7
0.79
0.48
2.4
0.45
0.096
0.083
0.024
0.058
0.094
0.059
0.016
0.010
0.026
0.039
0.0066
0.00075
0.00035
0.000012
0.00065
0.00014
.-
-
1,300
13
63
Source: ASAE, 1993.
6-25
-------
Lander averaged values from the Midwest Plan Service, USD A, and NCSU data sets for N, P,
and K. In all cases, EPA compared the averaged values to ASAE's data and determined them to
be comparable to the lactating cow numbers. As stated earlier in this section, the milking status
of dairy cattle can affect the excreted levels of N, P, and K. Lactating cows are expected to have
a higher nutrient content in their manure because they typically are fed a higher energy diet.
Table 6-38 presents the nutrient values in dairy manure from Lander's analysis.
i
Table 6-38. Average Nutrient Values in Fresh (As-Excreted) Dairy Manure
Parameter
Nitrogen (Total KjeldaM)
Phosphorus (Total)
Potassium
Dairy Cow Qb/day/l,000-lb animal) a
0.45
0.08
0.28
Source: Lander, 1998.
•Lander's analysis relied on 1990 North Carolina State University data, while the North Carolina State University data presented in this report is
from 1994.
6.3.2.2 Composition of Stored or Managed Waste
Dairy manure is often combined with large amounts of water and collected and stored in a
number of different ways (see Section 4.3.5 for a detailed discussion of dairy waste
management). This wastewater, therefore, has different physical properties than "as-excreted"
manure. This section presents dairy waste values for waste from milking centers and waste
managed in lagoons. :
Milking Centers
Milking centers, which include the milk room, milking parlor,, and holding area, produce about
15 percent of the total solids, at a dairy. Milking centers that do not practice waste flushing use
about 1 to 3 gallons of fresh water per day for each cow milked. However, dairies that use flush
cleaning and automatic cow washing use as much as 30 to 50 gallons/day/cow or more (London
etal., 1985).
Waste associated with milking centers varies among the different rooms. Milk room waste
typically consists of wash water associated with cleaning pipelines and holding tanks. This waste
could be disposed of via septic tank systems, but many dairies include it in then- manure waste
management systems. Milk parlor waste typically consists of some manure and wash water from
cleaning the milking equipment. Holding area waste generally contains more manure than the
milk parlor and also contains wash water from cleaning the cows and flush water from cleaning
the area. Many dairies remove solids from milking center waste prior to storing the liquid waste
in a lagoon. Table 6-39 presents USDA/NRCS data characterizing dairy waste from milking
centers.
6-26
-------
Table 6-39. Dairy Waste Characterization—Milking Center
Component
Volume
Moisture
Total Solids
Volatile Solids
Fixed Solids
COD
BOD
N
P
K
C:N ratio
Units
ftVd/l,000#
%
% wet basis
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
unitless
Milking Center
Milk Room
0.22
99.72
0.28
12.9
10.6
25.3
-
0.72
0.58
1.5
10
Milk Room +
Milk Parlor
0.6
99.4
0.6
35
15
41.7
8.37
1,67
0.83
2.5
12
Milk Room +
Milk Parlor +
Holding Area2
1.4
99.7
0.3
18.3
6.7
-
-
1
0.23
0.57
10
Milk Room +
Milk Parlor +
Holding Areab
1.6
98.5
1.5
99.96
24.99
-
-
7.5
0.83
3.33
7
' Holding area scraped and flushed - manure removed via solids separator.
b Holding area scraped and flushed - manure included.
Source: USDA/NRCS, 1992.
Lagoons
Lagoons that-receive a significant loading of waste (e.g., from the holding area, freestall barn,
and dry lots) generally operate in an anaerobic mode. Anaerobic dairy lagoon sludge
accumulates at a rate of about 0.073 fWpounds of total solids. This is equivalent to about 266
ftVyear/l ,000-pound lactating cow, assuming that 100 percent of the waste is placed in the
lagoon (USDANRCS, 1992). -
Typically, storage and/or treatment reduces nitrogen in dairy manure by 30 percent to .75 percent
through volatilization with only minor decreases in potassium and phosphorus. Although the
values of potassium and phosphorus are low in the supernatant, which is removed on a regular
basis, a disproportionate amount-of the phosphorus and potassium can be found concentrating in
the bottom sludge in lagoons and storage areas (Lander, 1999). Table 6-40 presents data on dairy
waste managed in lagoons.
• 6-27
-------
Table 6-40. Dairy Waste Characterization—Lagoons
Component
Moisture
Total Solids
Volatile Solids
Fixed Solids
COD
BOD
N
NH4-N
P
K
C:N ratio
Copper
Zinc
Units
%
% wet basis
lb/1,000 gal
lb/l,000gal
lb/1,000 gal
lb/1,000 gal
lb/l,000igal
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
unitless
Ib/lb
Ib/lb
Lagoon
Anaerobic -
Supernatant
99.75
0.25
9.16
11.66
12.5
2.92
1.67
1
0.48
4.17
3
-
-
Anaerobic -
Sludge
90
10
383.18
449.82
433.16
-
20.83
4.17
9.16
12.5 .
10
7.64 xlO"4
1.22 xlO'3
Aerobic -
Supernatant
99.95
0.05
1.67
2.5
1.25
0.29
0.17
0.1
0.08
-
-
-
-
Source: USDA/NRCS, 1992 and NCSU, 1994.
63.23 Composition of Aged Manure/Waste
Dairy manure characteristics after excretion vary from operation to operation, and within the
same operation during the year. Manure undergoes many changes after excretion, including
moisture change (dilution or consolidation), volatilization, oxidation, and reduction. These
changes always affect the "as-excreted" manure characteristics. For example, it is estimated that
as much as 50 percent to 60 percent of nitrogen in the urine portion of the manure can be lost
during the first hours after excretion if some measure is not taken to preserve it (Lander, 1999).
Phosphorus and potassium losses during storage are considered negligible except in open lots or
lagoons. In open lots, about 20 percent to 40 percent of phosphorus and 30 percent to 50 percent
of potassium can be lost by runoff and leaching. Up to 80 percent of the phosphorus in lagoons
can accumulate in bottom sludges (USDA ARS, 1998).
Characteristics of stored manure either are altered over time, or they are conserved (mass).
Nitrogen, for example, is volatilized in the form of ammonia and is lost from the system. On the
other hand, most of the compounds in manure (e.g., phosphorus, metals) remain in the manure
over time, and are considered to be conserved. Treating the manure often reduces the
concentration of nonconservative elements, such as nitrogen and the organic compounds, thus
reducing oxygen demands in further treatment (Lander, 1999). Table 6-41 presents North
Carolina State University data on scraped dairy manure from a paved surface.
6-28
-------
Table 6-41. Dairy Manure Characteristics Per 1,000 Pounds Live Weight Per Day From
Scraped Paved Surface
Parameter
Total solids
Volatile solids
Nitrogen (Total Kjeldahl)
Nitrogen (Ammonia)
Phosphorus (Total)
Potassium
Unit"
Ib
Ib
Ib
Ib
Ib
Ib
Value
13.7
11.5
0.32
0.077
0.097
0.22
"All values wet basis.
Source: NCSU, 1994.
6.4 Beef and Heifer Waste
This section describes the characteristics of beef and heifer manure and waste, hi this section,
manure refers to the combination of feces and urine and waste refers to manure plus other
material, such as hair, soil, and spilled feed. Due to the nature of beef and veal operations,
however, even fresh manure may also contain small amounts of hair, soil, and feed.
This section discusses the following:
• Section 6.4.1: The quantity of manure generated; and
• Section 6.4.2: Description of waste constituents and concentrations.
6.4.1 Quantity of Manure Generated
Numerous analyses have estimated average manure quantities from beef cattle. Four major data
sources that contain mean values for beef manure characteristics are identified below:
American Society of Agricultural Engineers (ASAE) Standard D384.1: Manure
Production and Characteristics, 1999. This data source contains national fresh (as-
excreted) manure characteristic values by animal type (e.g., dairy, beef, veal, swine).
USDA, Agricultural Waste Management Field Handbook, Chapter 4, 1996. This data
source contains national manure characteristic values for fresh and managed manure (e.g.,
lagoon supernatant, feedlot runoff) by animal type including subtypes such as lactating
cow, dry cow, heifer, sow, and boar.
North Carolina State University (NCSU), Livestock Manure Production and.
Characterization in North Carolina, 1994. This data source contains regional manure
characteristic values for fresh and managed manure by animal type including subtypes.
'6-29
-------
Midwest Plan Service-18 (MWPS): Livestock Waste Facilities Handbook, 1985. This
data source contains national fresh manure characteristic values by animal type and
animal weight
A recent analysis conducted by Charles Lander, et al. of the USDA/NRCS used a composite of
three of these data sources (Lander et al., 1998). Lander removed ASAE data before averaging to
prevent double counting of the ASAE information that is included in the Midwest Plan Service
data. Table 6-42 presents the fresh or "as-excreted" manure estimates from Lander's analysis for
beef and heifer cattle. In this analysis the average weight of a heifer was assumed to be 550
pounds and the only data source with heifer manure weight information was North Carolina State
University. ,
Table 6-42. Weight of Beef and Heifer Manure, "As-Excreted"
Quantity of Manure (wet basis)
Weight (lb/day/l,000-lb animal)
Weight (lb/year/l,000-lb animal)
Steer, Bulls, and Calves
58
21,170'
Beef Cows
63
22,995
Heifers
66
24,090
Source: Lander, 1998.
6.4.2 Description of Waste Constituents and Concentrations
The composition and concentrations of beef and heifer waste varies from the tune that it is
excreted to the time it is ultimately used as a fertilizer and/or soil amendment. Nutrients and
metals are expected to be present in beef waste due to the constituents of the feed. This section
discusses the following:
• Section 6.4.2.1: Composition of "as-excreted" manure;
• Section 6.4.2.2: Composition of beef feedlot waste;
• Section 6.4.2.3: Composition of aged manure; and
• Section 6.2.2.4: Composition of runoff from beef feedlots.
6A.2.1 Composition of "As-Excreted" Manure
Data are presented in Table 6-43 for 13 metals and nutrients found in fresh beef cattle manure.
Nitrogen is present in manure in four forms: ammonium-N, nitrate-N, nitrite-N, and organic-K
The total nitrogen (N) is the sum of these four components, while the total Kjeldahl nitrogen
(TKN) is the sum of the organic-N and ammonium-N. Phosphorus is present in manure in
inorganic and organic forms and presented as total phosphorus. Colonies of the pathogens
coliform and streptococcus bacteria have also been identified in beef manure.
Manure characteristics for beef cattle are highly variable and greatly influenced by the diet and
age of the animals. Differences in weather, season, degree of confinement, waste collection
systems, and overall management procedures used by feedlots across the nation add to the
6-30
-------
variability of manure characteristics in feedlots. The largest variable in fresh manure is moisture
content, which significantly decreases over time. Another major variable is the ash content,
which depends on the amount of soil entrained in the manure. Ash content also depends on the
degree to which the manure has been degraded, which is a function of time since deposition,
moisture conditions, temperature, and oxygen saturation (Sweeten et al., 1997). Ash content for
fresh manure has been reported as 15.3 percent dry basis (Sweeten, 1995), while ash content for
aged feedyard waste has been reported as high as 66 percent dry basis (TABS, 1996).
The nitrogen content of manure can begin to decrease rapidly after excretion. The urea-nitrogen
fraction part of the fecal protein rapidly converts to ammonia. Some measurements of ammonia
concentrations hi air around feedyards have indicated that about half of the nitrogen deposited in
urine, or about one-fourth of the total N deposition of the feedlot surface, is lost to the
atmosphere as ammonia gas (NH3). The rate of ammonia emissions depends on temperature, pH,
humidity, and moisture conditions, and it has been found to nearly triple as manure dries after
rainfall (Sweeten et al., 1997).
Table 6-43 presents beef and veal manure characteristics data, which are averages reported in the
scientific literature and compiled by ASAE. Lander averaged values from the Midwest Plan
Service, USDA-NRCS, and North Carolina State data sets for N, P, and K. Table 6-44 presents
Lander's averaged values.
6-31
-------
Table 6-43. Fresh Beef and Veal Manure Characteristics
Per 1,000 Pound Live Weight Per Day
Parameter
Moisture
Weight
Total solids
Volatile solids
BOD (5-day)
COD
pH
Nitrogen (Total Kjeldahl)
Nitrogen (Ammonia)
Phosphorous (Total)
Orthophosphorus
Potassium
Calcium
Magnesium
Sulfur
Sodium
Iron
Manganese
Boron
Molybdenum
Zinc
Copper
Total coliform bacteria
Fecal coliform bacteria
Fecal streptococcus
bacteria
Unit"
%
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ifa
Ib
Ib
Ib
Ib
Ib
Ib
colonies
colonies
colonies
Beef
Mean
88.4
58
8.5
7.2
1.6
7.8
7.0
0.34
0.086
0.092
0.030
0.21
0.41
0.049
0.045
0.0030
0.0078
6.0012
0.00088
0.000042
0.0011
0.00031
29
13
14
Standard
Deviation
-
17
2.6
0.57
0.75
2.7
0.34
0.073
0.052
0.027
!
0.061
0.11
0.015
0.0052
0.023
0.0059
J 0.00051
0.000064
-
0.00043
0.00012
27
12
21
Veal
Mean
97.5
62
5.2
2.3
1.7
,5.3
8.1
0.27
0.12
0.066
-
0.28
0.059
0.033
-
0.086
0.00033
-
-
-
0.013
0.000048
-
-
-
Standard Deviation
-
24
2.1
-
.• -
.
-
0.045
0.016
0.011
-
0.10
0.049
0.023
-
0.063
-
-
-
-
-
-
-
-
Source: ASAE, 1993.
6-32
-------
Table 6-44. Average Nutrient Values in Fresh (As-Excreted) Beef Manure
Parameter
Nitrogen (Total Kjeldahl)
Ammonia
Phosphorus (Total)
Potassium
Beef (lb/day/l,000-lb animal)'
0.32
Not provided
0.098
0.23
1 Lander's analysis relied upon 1990 North Carolina State University data, while the North Carolina State University
data presented in this report is from 1994.
Manure characteristics of heifers is limited to two data sources, North Carolina State University
andUSDA, Agricultural Waste Management Field Handbook, Chapter 4,1996. Table 6-45
presents the fresh (as-excreted) manure characteristics for heifers.
6-45. Fresh Heifer Manure Characteristics Per 1,000 Pounds Live Weight Per Day
Parameter
Moisture
Weight
Total solids
Volatile solids
Biochemical oxygen demand (BOD), 5-day
Chemical oxygen demand (COD)
Nitrogen (Total Kjeldahl)
Phosphorus (Total)
Potassium
Unit"
%
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
USDA Mean Value
89.3
85
9.14
7.77
1.3
: 8.3
0.31
0.04
0.24
NCSU Mean Value
-
68.4
7.35
5.34
0.89
5.68
0.23
0.16
0.16
aAll values wet basis.
Sources: USDA, 1996; NCSU, 1994
6.4.2.2 Composition ofBeefFeedloi Waste
The characteristics of beef cattle feedlot wastes vary widely because of differences in climate,
rainfall, diet, feedlot surface, animal density, and cleaning frequency. Wasted feed and soil in
unpaved beef feedlots is readily mixed with the manure because of animal movement and
cleaning operations (Arrington et al., 1981). Therefore, due to the incorporation of more solids
and exposure to the elements, the moisture content of beef feedlot waste is significantly lower
than for "as-excreted" beef manure.
Table 6-46 presents characteristics of beef waste, as collected, from unpaved and paved feedlots
(USDA NRCS, 1992). Most feedlots are unpaved; however, for paved lots, concrete is the most
6-33
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common paving material, although other materials (e.g., fly ash) have been used (Suszkiw,
1999),
Table 6-46. Beef Waste Characterization—Feedlot Waste
Component
Weight
Moisture
Total Solids
Total Solids
Volatile Solids
Fixed Solids
N
P
K
C:N ratio
Units
lb/d/1000#
%
% wet basis
lb/d/1000#
lb/d/l,000#
lb/d/l,000#
lb/d/l,000#
lb/d/l,000#
lb/d/l,000#
unitless
Unpaved Lot*
17.5
i 45
i 55
9.6
4.8
4.8
0.21
0.14
0.03
13
Paved Lot*
High-Forage Diet
11.7
53.3
46.7
5.5
3.85
1.65
-
'
,
-
High-Energy
Diet
5.3
52.1
47.9
• 2.5
1.75
0.76
-
-
-
•
Dry climate (annual rainfall less than 15 inches); annual manure removal.
fc Dry climate; semiannual manure removal. j
Source: USDANRCS, 1992.
Table 6-47 presents North Carolina State University data on scraped beef manure from an
unpaved surface.
6-47. Beef Manure Characteristics Per 1,000 Pounds Live Weight Per Day From Scraped
Unpaved Surface
Parameter
Total solids
Volatile solids
Nitrogen (Total Kjeldahl)
Nitrogen (Ammonia)
Phosphorus (Total)
Potassium
Unif
Ib
Ib
Ib
Ib
Ib
Ib
Value
9.4
5.3
0.20
0.38
0.062
0.14
Sweeten, et al., compiled and compared feedlot waste data representing "as-collected" waste,
composted waste, and stockpiled waste from one area of the country (Sweeten et al., 1997).
Overall, the as-collected, composted, and stockpiled data were similar, indicating that once
manure is exposed to the elements, its nutrient composition does not significantly change even if
it is composted or stockpiled.
6-34
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6.4.2.3 Composition of Aged Manure
Beef cattle feedlots typically scrape and remove the manure that is deposited on the ground about
every 120 to 365 days, as opposed to dairy operations that scrape or remove manure as often as
every day. During this "aging" process, nutrients are lost due to ammonia volatilization, runoff,
and leaching. Mathers, et al., determined average nutrient concentrations in aged manure ready
for land application from 23 beef cattle feedlots in the Texas High Plains (Mathers et al., 1972).
Since national data on aged manure characteristics have not been identified, these local data are
presented in Table 6-48 to demonstrate the significant difference in characteristics of fresh and
aged manure.
These data show the aged beef manure nitrogen concentration is 40.3 percent of the fresh manure
concentration, while phosphorus and potassium in aged manure are 50.9 percent and 64.5 percent
of their concentrations, respectively, in fresh manure. Nitrogen losses as high as 50 percent have
been reported in aged beef manure, due to temperature, moisture, pH, and C:N ratio. Phosphorus
and potassium losses are primarily due to runoff but some leaching may also occur.
Table 6-48. Percentage of Nutrients in Fresh and Aged Beef Cattle Manure
Parameter
Moisture
N .
P
K
Unit
%
% dry basis
% dry basis
% dry basis
Fresh Manure
88
5.08
1.59
3.55
Aged Manure
34
2.05
0.81
2.29
6.4.2.4 Composition of Runoff from Beef Feedlots
Numerous analyses characterizing the runoff from beef feedlots have been conducted on a local
level. However, manure characteristics data collected at a local level may not be representative
of the beef industry as a whole. Since the constituent concentration of feedlot runoff varies
among different areas of the counfty, this report presents only nationally available manure
characteristics and regional estimates of feedlot runoff characteristics.
As with feedlot wastes, constituent characteristics of beef feedlot runoff also vary across the
country. The factors that are responsible for runoff waste variations are similar to those for
feedlot wastes (i.e., climate, rainfall, diet, feedlot surface, animal density, and cleaning
frequency). Paved feedlots produce more runoff than unpaved lots and areas of high rainfall and
low evaporation produce more runoff than arid areas.
The USDA/NRCS Agricultural Waste Management Field Handbook characterizes both the
supernatant and sludge from beef feedlot runoff lagoons. Table 6-49 presents these waste
characteristics.
6-35
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Table 6-49. Beef Waste Characterization—Feedlot Runoff Lagoon
Component
Moisture
Total Solids
Volatile Solids
Fixed Solids ,
COD
N
NIVN
P
K
Copper
Zinc
Units
%
% wet basis
lb/l,000gal
, lb/1,000 gal
lb/1,000 gal
lb/l,000gal
lb/1,000 gal
lb/1,000 gal
lb/1,000 gal
Ib/lb
Ib/lb
Runoff Lagoon
Supernatant
99.7
0.3
7.5
17.5
11.67
1.67
1.5
_a
7.5
-
-
Sludge
82.8
17.2
644.83
788.12
644.83
51.66
_a
17.5
14.17
1.94X10-4
9.29 x 10-4
Data not available.
Source: USDANRCS, 1992; NCSU, 1994.
6.5 Veal Waste
This section describes the characteristics of veal manure and waste. In this section, manure
refers to the combination of feces and urine and waste refers to manure plus other material, such
as hair, soil, and spilled feed. Due to the nature of veal operations, however, even fresh manure
may also contain small amounts of hair and feed.
This section discusses the following: , >'
t
• Section 6.5.1: The quantity of manure generated; and
• Section 6.5.2: Description of waste constituents and concentrations.
6.5.1 Quantity of Manure Generated
National data on veal waste characteristics are available from the following three data sources:
• American Society of Agricultural Engineers (ASAE) Standard D384.1: Manure
Production and Characteristics, 1999. This data source contains national fresh (as-
excreted) manure characteristic values by animal type (e.g., dairy, beef, veal, swine).
• USD A, Agricultural Waste Management Field Handbook, Chapter 4,1996. This data
source contains national'manure characteristic values for fresh and managed manure (e.g.,
6-36
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lagoon supernatant, feedlot runoff) by animal type including subtypes such as lactating
cow, dry cow, heifer, sow, and boar.
North Carolina State University (NCSU), Livestock Manure Production and
Characterization in North Carolina, 1994. This data source contains regional manure
characteristic values for fresh and managed manure by animal type including subtypes.
Table 6-50 presents the average as-excreted manure characteristics for veal from these three data
sources.
f
6-50. Average Weight of Veal Manure, "As-Excreted"
Quantity of Manure (wet basis)
Weight (lb/day/l,000-lb animal)
Weight (lb/year/l,000-lb animal)
Veal Calves
61
22,265
6.5.2 Description of Waste Constituents and Concentrations
The composition and concentrations of veal waste varies from the time that it is excreted to the
time it is ultimately used as a fertilizer and/or soil amendment. Nutrients arid metals are
expected to be present in veal waste due to the constituents of the feed. This section discusses
the composition of "as-excreted" manure.
Data are presented in Table 6-51. for nine metals and nutrients found in fresh veal manure. Veal
manure is very fluid, with the consistency of a sloppy mortar mix, and is often diluted by large
volumes of wash water (Meyer, 1987). The moisture content of fresh veal manure is
approximately 98 percent (USDA NRCS, 1992).
Veal manure is typically stored in tanks, basins, and pits until it is pumped out on the land as
fertilizer. However, most of the fertilizer value of veal manure remains in the solids in a settling
tank (Meyer, 1987). Over time, the most significant compositional change in veal manure, stored
in pits, is the conversion of organic-N in fresh manure to ammonium and loss of total nitrogen to
the atmosphere in the form of ammonia. Much of the high ammonia loss is due to microbial
degradation of the organic matter including total nitrogen components (Sutton et al., 1989).
6-37
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6-51. Fresh Veal Manure Characteristics Per 1,000 Pound Live Weight Per Day
Parameter
Moisture .
Weight
Total solids
Volatile solids
BOD (5-day)
COD
PH
Nitrogen (Total Kjeldahl)
Nitrogen (Ammonia)
Phosphorous (Total)
Potassium
Calcium
Magnesium
Sodium
Iron
Zinc
Copper
Unit"
%
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Ib
Mean Values from Data Sources
ASAE
97.5
62
5.2
2.3 •
1.7.
5.3
8.1
0.27
0.12
0.066
0.28
0.059
0.033
0.086
0.00033
0.013
0.000048
USDA
97.5
60
1.5
0.85
0.37
1.5
-
0.20
—
0.03
0.25
-
-
r-
-
-.
-
NCSU
-
61.8
4.0
2.1
0.83
1.5
7.7
0.24
0.11
0.053
0.27
0.059
0.33
0.16
0.00033
0.013
0.000048
All values wet basis.
Source: ASAE, 1999; USDA, 1996; NCSU, 1994.
6-38
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6.6 References
Arlington, R.M. and C.E. Pachek. 1981. Soil Nutrient Content in Manures in an Arid Climate.
In: Livestock Waste: A Renewable Resource, Proceedings of the Fourth International
Symposium on Livestock Waste, 1980. pp. 15-152. American Society of Agricultural
Engineers, St. Joseph, Michigan.
ASAE, 1998. AS AE Standards 1998,45th Edition. American Society of Agricultural Engineers,
St. Joseph, MI.
ASAE, 1999. Manure Production and Characteristics. American Society of Agricultural
Engineers, St. Joseph, ML
Blume and McCleve. 1997. Disposal of Swine Wastewater Using Spray Nozzle. ASAE Paper
No. 974072. Presented at the ASAE Annual International Meeting. American Society of
Agricultural Engineers, Minneapolis, Minnesota, August 10-14, 1997.
Boland et al. 1997. Analysis of Manure Management Systems and Phytase Adoption by Pork
Producers. Livestock Environment 5, Volume 2. Proceedings of the Fifth International
Symposium, Bloomington, Minnesota, USA, May 29-31, 1997. Pp. 702-709.
Fulhage. 1998. Composting Dead Animals-The Missouri Experience. Presented at the ASAE
Annual International Meeting. American Society of Agricultural Engineers, Orlando
Florida, July 12-16, 1998.
Jones, Don D., and Alan Sutton. 1994. "Treatment Options for LiquidManure"in Liquid
Manure Application Systems: Design, Management, and Environmental Assessment,
Proceedings from the Liquid Manure Application Systems Conference. Rochester, New
York, Dec. 1-2, 1994. .
Lander, C.H., D. Moffitt, and K. Alt. 1998. Nutrients Available from Livestock Manure Relative
to Crop Growth Requirements. U.S. Department of Agriculture. Natural Resources
Conservation Services. Washington, D.C.
Lander, C.H. 1999. Dairy Manure Characteristics. National Milk Producers Federation
submittal to EPA.
Loudon, T.L., et. al. 1985. Livestock Waste Facilities Handbook, 2nd ed., Midwest Plan Service.
Mathers, A.C., B.A. Stewart, J.D. Thomas, andBJ. Blair. 1972. Effects of Cattle Feedlot
Manure on Crop Yields and Soil Conditions. USDA Southwestern Great Plains Research
Center Tech. Rep. No. 11, Bushland, TX.
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Meyer, D. J. 1987. Animal Manure—Veal Calf Management. Prepared under the direction of
the Manure Management Work Group of the Agricultural Advisory Committee to the
Pennsylvania Department of Environmental Resources, Robert E. Graves, Ed.
'
Midwest Planning Service. Livestock Waste Facilities Handbook, 1985.
MWPS. 1993. MWPS-18: Livestock Waste Facilities Handbook -3rdEdition. Midwest Plan
Service, Iowa State University, Ames, IA.
NCSU. 1994. Livestock Manure Production and Characterization in North Carolina. North
Carolina Cooperative Extension Service. Raleigh, NC.
Suszkiw, J. 1999. Low-Cost Way to Pave Feedlots. Agricultural Research.
Sutton. A.L., M.D. Cunningham, J.A. Knesel, andD.T. Kelly. 1989. Veal Calf Waste Production
and Composition. Applied Engineering in Agriculture, Vol 5, No. 1.
Svoboda. 1995. Nitrogen Removal from Pig Slurry by Nitrification and Denitrification.
Proceedings of the Seventh International Symposium on Agricultural and Food
Processing Wastes, Chicago, Illinois, USA, June 18-20,1995. Pp. 702-709.
Sweeten, J.M. and.SJH. Amosson. 1995. Total Quality Manure Management, Texas Cattle
Feeders Association. Chapter 4: Manure Quality and Economics.
USDAARS.' 1998. Agricultural Uses of Municipal, Animal and Industrial Byproducts.
U.S. Department of Agriculture (SDA), Agricultural Research Service (ARS).
.
Sweeten, J.M., S.H. Amosson, and B.W. Auvermann. 1997. Manure Quality and Economics.
Proceedings of Texas Biomass Energy Opportunities Workshop Series #1: Livestock
Waste Streams: Energy and Environment. Texas A&M University Agricultural Research
and Extension Center.
TABS. 1996. Manure Analysis Summary—Coal Ash Surfacing vs Control Treatments for Beef
Cattle Feedyards. Result Demonstration Report. Texas Agricultural Extension Service
(TAES). :
USDA. 1992. National Engineering Handbook: Agricultural Waste Management Field
Handbook. United States Department of Commerce, National Technical Information
Service. Springfield, VA; Handbook also revised July 1996.
USDA. 1998. Nutrients Available from Livestock Manure Relative to Crop Growth
Requirements. U.S. Department of Agriculture, Natural Resources Conservation Service, ,
6-40 • '
-------
Resource Assessment and Strategic Planning Working Paper 98-1.
. Accessed August 23, 1998.
USDA. 1999. 1997 Agricultural Resource Management Study (ARMS). Economic Research
Service, 2/18/99.
USDA APHIS. 1995. Swine '9,5 Part I: Reference of 1995 Swine Management Practices.
. File sw95desl.pdf accessed October 15,
1998. U.S. Department of Agriculture, Animal and Plant Health Inspection Service.
USDANRCS. 1992. Agricultural Waste Management Field Handbook, National Engineering
Handbook (NEH), Part 651. U.S. Department of Agriculture (USDA), Natural Resources
Conservation Service (NRCS).
Van Horn, H.H., G.L. Newton, R.A. Nordstedt, B.C. Krench, G. Kidder, D.A. Graetz, and C.F.
Chambliss. 1998. Circular 1016: Dairy Manure Management: Strategies for Recycling
Nutrients to Recover Fertilizer Value and Avoid Environmental Pollution. Dairy and
Poultry Sciences Department, Florida Cooperative Extension Service, Institute of Food
and Agricultural Sciences, University of Florida.
Zublena, J. P., Barker, Parker, and Stanislaw. 1993. Soil Facts. North Carolina Cooperative
Extension Service.
6-41
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CHAPTER 7
POLLUTANTS OF INTEREST
7.0 INTRODUCTION
Pollution generated at feedlot operations can arise from multiple sources. These sources,
including animal waste, process wash waters, litter, animal carcasses, spills of pesticides, and
Pharmaceuticals, are the primary sources of potential environmental contamination.
Excreted animal waste contains undigested and partially digested feed, partially metabolized
organic material, dead and living microorganisms from the digestive tract, cell wall material and
other organic debris from the digestive tract, excess digestive juices, and other organisms that
might have grown hi the wastes after excretion. Depending on the type of feed provided to the
animals and whether feed additives have been used, animal wastes can also contain
Pharmaceuticals and inorganics such as trace elements.
Animal carcasses, which may contain pathogens, nutrients, and chemical toxicants, can pose an
environmental problem, especially in the poultry industry where many operations have
historically used burial as a means for disposal. For example, during 1990, several state agencies
ha Arkansas tested the management of dead-bird disposal pits and found high soil concentrations
of ammonium (USEPA, 1999). Improper disposal of poultry carcasses has been implicated hi
ground water contamination; however, hi recent years, greater regulation of animal disposal has
reduced the risk of environmental contamination from buried animal carcasses. Arkansas, for
example, has outlawed the use of dead-bird disposal pits. Other states have also issued
guidelines or regulations for disposal of animal carcasses and require operators to use specific
practices such as composting.
hi the preliminary study on environmental impacts from animal feedlot operations, EPA (1998)
identified and described the major animal waste constituents that can adversely affect the
environment. Additional information on potential impacts can be found in the Environmental
Assessment of Proposed Revisions to the National Pollutant Discharge Elimination system
Regulation and Effluent Limitations Guidelines for Concentrated Animal Feeding Operations
(USEPA, 2000). As demonstrated hi Chapter 6, the physical and chemical characteristics of
manure differ between animal sectors as well as within animal sectors. The following pollutants
of interest identified by EPA hi its preliminary feedlots study are described below:
7-1
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• Biochemical oxygen demand (BOD)
• Chemical oxygen demand (COD)
• Total suspended solids
• Nutrients (nitrogen, phosphorus)
• Pathogens
• Other contaminants, including salts, trace elements, and Pharmaceuticals
7.1 Conventional Waste Pollutants
Biochemical Oxygen Demand
BOD is a measure of the oxygen-consuming requirements of organic matter decomposition.
When animal waste is discharged to surface water, it is decomposed by aquatic bacteria and other
microorganisms. Decomposing organic matter consumes oxygen and reduces the amount
available for aquatic animals. Severe reductions in dissolved oxygen levels can lead to fish kills.
Even moderate decreases in oxygen levels can adversely affect waterbodies through decreases in
biodiversity as manifested by the loss of fish and other aquatic animal populations.
Total Suspended Solids
Suspended solids can clog fish gills and increase turbidity. Increased turbidity reduces
penetration of light through the water column, thereby limiting the growth of desirable aquatic
plants that serve as a critical habitat for fish, shellfish, and other aquatic organisms. Solids that
settle out as bottom deposits can alter or destroy habitat for fish and benthic organisms. Solids
also provide a medium for the accumulation, transport, and storage of other pollutants, including
nutrients, pathogens, and trace elements. Sediment-bound pollutants often have an extended
interaction with the water column through cycles of deposition, resuspension, and redeposition.
Fecal Coliform Bacteria.
Manure contain diverse microbial populations. Included are members of the normal
gastrointestinal tract flora, such as members of the" fecal coliform and fecal streptococcus groups
of bacteria. These are the groups of bacteria commonly used as indicators of fecal contamination
and the possible presence of pathogenic species. A discussion of the different types of pathogens
found in the waste of AFOs is given in section 7.2.
7.2 Nonconventional Pollutants
Nutrients (Nitrogen, Phosphorus)
Because of its nutrient content, animal manure can serve as a valuable agricultural resource. In an
area where the amount of nutrients in manure generated from animal feedlot operations is greater
than the nutrient requirements of the crops grown in the area, excess land application might
7-2
-------
occur, leading to increased nutrient runoff and seepage and subsequent degradation of water
resources.
As noted in Chapter 6, wastes contain significant quantities of nutrients, particularly N and P.
• Manure N occurs primarily in the form of organic N and ammonia-N compounds. In organic
form, N is unavailable to plants. However, through bacterial decomposition, organic N is
transformed into ammonia, which is oxidized (by nitrification) to nitrite and ultimately nitrate.
Ammonia and nitrate are bioavailable and therefore have fertilizer value. These forms can also
produce adverse environmental impacts when they are transported hi excess quantities to the
environment.
Ammonia. "Ammonia-N" includes the ionized form (ammonium) and the un-ionized form
(ammonia). Ammonium is produced when microorganisms break down organic N products,
such as urea and proteins, in manure. This decomposition can occur in both aerobic and
anaerobic conditions. Both forms are toxic to aquatic life, although the un-ionized form
(ammonia) is much more toxic.
Ammonia is of environmental concern because it exerts a direct biochemical oxygen demand on
the receiving water. Ammonia can lead to eutrophication, or nutrient overenrichment, of surface
waters. Ammonia itself is a nutrient and is also easily transformed to nitrate (another nutrient
form of N) in the presence of oxygen. Although nutrients are necessary for a healthy ecosystem,
the overabundance of nutrients (particularly N and P) can lead to nuisance algae blooms.
Nitrate. In the biochemical process of nitrification, aerobic bacteria oxidize ammonium to nitrite
(NO2).and then to nitrate (NO3). Nitrite is toxic to most fish and other aquatic species, but it
usually does not accumulate in the environment because of its rapid conversion to nitrate in an
aerobic environment.
Nitrate is a valuable fertilizer because it is biologically available to plants. Excessive levels of
nitrate in drinking water, however, can produce adverse human health and environmental
impacts. For example, human infants exposed to high levels of nitrate can develop
methemoglobinemia, commonly referred to as "blue baby syndrome" because the lack of oxygen
can cause the skin to appear bluish in color. To protect human health, EPA has set a drinking
water maximum contaminant level (MCL) of 10 mg/L for nitrate-N.
Phosphorus. Animal wastes contain both organic and inorganic forms of P. As with N, the
organic form must mineralize to the inorganic form to become available to plants. Mineralization
occurs as the manure ages and the organic P hydrolyzes to inorganic phosphate-containing
compounds. Phosphorus is of concern hi surface waters because it is a nutrient that can lead to
eutrophication and the resulting adverse impacts—fish kills, reduced biodiversity, objectionable
tastes and odors, increased drinking water treatment costs, and growth of toxic organisms. At
concentration levels greater than 1.0 mg/L, P can interfere with coagulation in drinking water
treatment plants (Bartenhagen et al., 1994).
7-3
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Phosphorus is of particular concern in fresh waters, where plant growth is typically limited by
phosphorous levels. Under high pollutant loads, however, fresh water may become nitrogen-
limited (Bartenhagen et al, 1994). Thus, both N and P loads may contribute to eutrophication.
Chemical Oxygen Demand
COD is another measure of oxygen-consuming pollutants in water, but it measures the amount of
oxygen required to oxidize all organic material present. COD differs from BOD in that it test
oxidizes organic material regardless of how biological assimilability of the substance. BOD only
measures the oxygen required to oxidize the biologically degradable material. COD is based on
the fact that all organic compounds, with few exceptions, can be oxidized by the action of strong
oxidizing agents under acidic conditions. COD ,is usually coincident with BOD, exacerbating the
adverse effects of organic matter degradation.
Pathogens
Manure contains diverse microbial populations. There are many examples that demonstrate that
pathogens from manure can be a problem. Other studies show that manured fields do not pose a
significant threat to surface waters. Most pathogens are from the gastrointestinal tract and can be
divided into those pathogens that are highly host-adapted and not considered to be zoonoses
(diseases naturally transmissible between vertebrates and man) and those that are capable of
causing infection in humans. For example, most Salmonellae are zoonoses, but S. pulloram and
S. gallinarum, which might be present in poultry manures, are not. However, both may be
included in gross estimates of Salmonella densities. The pathogens that might be present in
poultry and swine manures also can be divided into those microorganisms which commonly are
present and those which are less common. For example in poultry manures, Campylobacter
jejuni is commonly present while Mycobacterium avium is less common. These distinctions are
important in assessing the potential public health risks associated with poultry and swine
operations, as well as other animal feeding operations.
The interactions between pathogens, cattle, and the environment are not well understood but
current literature suggests that dairy and beef cattle shed pathogens that are known to be
infectious to humans. The threat posed by pathogens in animal manure is influenced by the
source, pH, dry matter, microbial, and chemical content of the feces. Solid manure that is mixed
with bedding material is more likely to undergo aerobic fermentation in which temperature
increases reduce the number of viable pathogens. However, some pathogens grow under a wide
range of conditions that makes their control very difficult. Quantifying the risk associated with
these pathogens is thus challenging. Rapidly changing pathogen numbers, changes in the
infective status of the host, and survivability of the pathogens all make it increasingly difficult to
determine how much of a threat animal-excreted pathogens are to society. Moreover, methods of
pathogen detection produce varying results, making it difficult to compare studies that use
different analyses (Pell, 1997).
7-4
-------
Ahhough.manures may contain a variety of pathogens capable of causing infectious diseases in
numans, it appears that Salmonellae, Campylobacterjejuni, Clostridium perfrinzens type A and
source fT mUlt°Cida Sh°Uld be of&eatest con<*rn. Only swine manure is a potential
t^K^l! I6* ^ G™rdias™ or Cryptosporidiosis infections in humans, and swine manure appears
to be far less significant than cattle manure as a source of the responsible protozoans.
Other Potential Contaminants
Animal wastes can contain other chemical constituents that could adversely affect the
environment These Constituents include salts, trace elements, and Pharmaceuticals, including
antibiotics. AMiough salts are usually present in waste regardless of animal or feed type trace
elements and Pharmaceuticals are typically the result of feed additives to help prevent disease or
°f *ese "-a— -* vary with operation type
Salts and trace elements. Animal manure contains dissolved mineral salts. The major cations
contributing to salinity are sodium, calcium, magnesium, and potassium; the major anions are
chloride, sulfate, bicarbonate, carbonate, and nitrate. In land-applied wastes, salinity is a concern
ou3Th 7* OTula*m ^ soil andbecome toxic to plants; they can also deteriorate soil
quality by reducing permeability and contributing to poor tilth. Direct discharges and salt runoff
to fresh surface waters contribute to salinization and can disrupt the balance of the ecosystem
Leaching salts can deteriorate ground water quality, making it unsuitable for human
consumption. Trace elements such as arsenic, copper, selenium, and zinc are often added to
animal feed as growth stimulants or biocides (Sims, 1995). When applied to land, these elements
^cumulate in soils and become toxic to plants, and they can affect human and ecological
Antibiotics and hormones. A number of pharmacologic agents are used in the production of
poultry and swine among them a variety of antibiotics. Nonantibiotic antimicrobials, such as
sulfonamides, and some antibiotics, such as streptomycin, are used primarily for therapeutic use
However, most of the antibiotics used in both the swine and the poultry industries are used both"
tiierapeutically and as feed additives to promote growth or improve feed conversion efficiency or
both. When antibiotics are used to promote growth or improve feed conversion, the dosage rates
are substantially lower than when they are administered for therapeutic use.
While specific hormones are used to increase productivity hi the beef and dairy industries
hormones are not used in the poultry or swine industries. Thus, hormones present in pouiy and
swine manures are only hi naturally occurring concentrations.
Despite the fact that there is little information in the literature about concentrations of antibiotics
in poultry and swine manures, it is known that the primary mechanisms of elimination are in
urine and bile (Merck and Company, 1998). Essentially all of an antibiotic administered is
eventually excreted. The form excreted, the unchanged antibiotic or metabolites or some
7-5
-------
combination thereof, is antibiotic specific, as is the mass distribution among mechanisms of
excretion These compounds may pose risks to humans and the environment. For example,
chronic toxicity may'result from low-level discharges of antibiotics. In addition, estrogen
hormones have been implicated in the drastic reduction in sperm counts among men (Sharpe and
Skakkebaek, 1993) and reproductive disorders in a variety of wildlife (Colburn et al., 1993).
7.3 Priority Pollutants
The Clean Water Act (CWA) requires states to adopt numeric criteria for priority toxic pollutants
if the USEPA has published criteria guidance and if the discharge or presence of these pollutants
could reasonably be expected to interfere with the designated uses of the state's waters. The
USEPA currently lists a total of 126 toxic priority pollutants in 40 CFR 122, Appendix D. Other
metal and organic chemicals, however, can cause adverse impacts.
Animal wastes may contain a variety of priority pollutants, including the potentially toxic metals:
arsenic, cadmium, chromium, copper, lead, molybdenum, nickel, selenium, and zinc (Overcash et
aL 1983- ASAE 1999). In promulgating standards for the disposal of sewage sludges by land
application, USEPA has established maximum allowable concentrations and cumulative loading
limits for each of these metals. Although information about the concentrations of these metals in
poultry and livestock manures, and its variability, is quite limited, it generally has been assumed
that these concentrations are well below those allowable for land application of wastewater
treatment sludges. However, the issue of cumulative loading has been raised periodically m light
of long-term use of cropland for manure disposal, especially in areas where poultry and livestock
production is concentrated (Sims, 1995).
Given the degree of vertical integration that has occurred in both the poultry and the swine
industries, much of the feed manufacturing for these industries is controlled by integrators. Thus,
information about the current use of trace mineral supplements in formulating both poultry and
swine feeds is difficult to obtain because the integrators consider it proprietary. However it
appears to be a reasonable assumption that arsenic, copper, selenium, and zinc are typically
added to poultry feeds and that copper, selenium, and zinc are common components of trace
mineral premixes used in the manufacturing of swine feeds. It is probable that commonly used
feed supplements also contain some manganese.
Feed amendments of selenium (0.3 part per million) and arsenic (90 grams per ton of feed) are
regulated by the U.S. Food and Drug Administration (Title 21, Part 573:920 of the Code of
Federal Regulations). Levels of other trace minerals as feed supplements are regulated only
indirectly by the FDA through maximum allowable concentrations in specified tissues at
slaughter or in eggs.
Currently available information about metal concentrations in poultry and swine manures almost
exclusively dates back to the -1960s and 1970s (Barker and Zublena, 1995). Komegay s(1996)
data are also somewhat dated, because they are averages over a 14-year period prior to 19)2.
When compared with Barker and Zublena's data for swine, Kornegay's data suggest that the
7-6
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concentrations of copper and zinc in swine manure have increased significantly over time.
However, little is known about the current concentrations of trace metals in poultry and swine
manures except that the variations in concentrations are substantial.
7.4 References
ASAE 1999. Manure production and characteristics. AS Data: AS D384.1. American Society of
Agricultural Engineers, St. Joseph, Michigan.
Barker, J.C., and J.P. Zublena. 1995. Livestock manure assessment in North Carolina. In
Proceedings of the Seventh International Symposium on Agricultural and Food Processing
Wastes, American Society of Agricultural Engineers, St. Joseph, Michigan, pp. 98-106.
Bartenhagen, Kathryn, et al. 1994. Water, Soil, and Hydro Environmental Decision Support
System (WATERSHEDS) NCSU Water Quality Group,
-------
USEPA. 1999. Success stories, Arkansas. U.S. Environmental Protection Agency, Washington,
DC. http://www.epa.gov/owow/NPS/Success319/AR.html. December 31,1998. Accessed
September 7,1999.
7-8
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CHAPTERS
TREATMENT TECHNOLOGIES AND
BEST MANAGEMENT PRACTICES
8.0 INTRODUCTION
This chapter provides an overview of treatment technologies and best management practices
(BMPs) for pollution prevention at animal feeding operations (AFOs), as well as for the
handling, storage, treatment, and land application of wastes. The discussion focuses on
technologies and BMPs currently implemented at domestic AFOs, but it also describes
technologies and BMP.s that are under research and development, are undergoing laboratory or
field testing, or are used in other countries.
Many waste management technologies and BMPs are used by more than one animal sector, and
information on them is presented in a general discussion form. However, the manner in which a
particular technology or BMP is used or its degree of acceptance can vary among sectors. These •
differences are presented by animal sector where necessary.
8.1 Pollution Prevention Practices
Pollution prevention practices can be divided into feeding strategies that reduce the concentration
of pollutants in waste and practices that reduce the amount of water used in the handling of
wastes. Reduced water use or handling of wastes in a dry or drier form lowers the risk of
pollutants entering surface waters. Reduced water use has the added benefit of making the waste
less expensive to move from the facility site.
8.1.1 Feeding Strategies
Feeding strategies designed to reduce nitrogen (N) and phosphorus (P) losses include more
precise diet formulation, enhancing the digestibility of feed ingredients, genetic enhancement of
cereal grains and other ingredients resulting in increased feed digestibility, and improved quality
control. These strategies increase the efficiency with which the animals use the nutrients in their
feed and decrease the amount of nutrients excreted in the waste. With a lower nutrient content,
more manure can be applied to the land and less cost is incurred to transport excess manure from
the farm. Strategies that focus on reducing P concentrations, thus reducing overapplication of P
and associated runoff into surface waters, can turn manure into a more balanced fertilizer in
terms of plant requirements. -
8-1
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Feeding strategies that reduce nutrient concentrations in waste have been developed for specific .
animal sectors, and those for the swine, poultry and dairy industries are presented separately in
the following discussion. The application of these types of feeding strategies to the beef industry
has lagged behind other livestock sectors and is not discussed here.
8.1.1.1 Swine Feeding Strategies I -
|
Practice; Precision Nutrition for Swine ;
Description: Current swine feed rations can result in overfeeding proteins and other nutrients to
animals because they are designed to ensure that nutritional requirements are met and growth rate
maintained. Precision nutrition entails formulating feed to meet more precisely the animals'
nutritional requirements, causing more of the nutrients to be metabolized, thereby reducing the
amount of nutrients excreted. For more precise feeding, it is imperative that both the nutritional
requirements of the animal and the nutrient yield of the feed are fully understood.
When swine are fed typical diets, the P use efficiency is on the order of 10 to 25 percent, while
the N use efficiency is on the order of 30 percent. These figures suggest that swine use these
nutrients very inefficiently. An excess of N in the diet, principally from protein in feed, leads to
inefficient utilization of nutrients. Phytate-phosphorus1 (phytate-P), the most common form of P
in feedstuff's (56 to 81 percent), is not well utilized by pigs because they lack intestinal phytase,
the enzyme needed to remove the phosphate groups from the phytate molecule. Therefore,
supplemental P is added to the diet to meet the pig's growth requirements, while phytate-P from
the feed is excreted in the urine, thus increasing P concentrations in the manure. Because some
feedstuff's are high in phytase, and because there is some endogenous phytase in certain small
grains (wheat, rye, triticate, barley), there is wide variation in the digestibility of P in feed
ingredients. For example, only 12 percent of the total P in corn is digestible whereas 50 percent
of the total P in wheat is digestible. The P in dehulled soybean meal is more available than the P
in cottonseed meal (23 versus 1 percent), but neither source of P is as highly digestible as the P in
meat and bone meal (66 percent), fish meal (93 percent), or dicalcium phosphate (100 percent).
Application and Performance: Lenis and Schutte (1990) showed that the protein content of a
typical Dutch swine ration could be reduced by 30 grams per kilogram without negative effects
on animal performance. They calculated that a 1 percent reduction in feed N could result in a 10
percent reduction in excreted N. Monge et al. (1998) confirmed these findings by concluding
that a 1 percent reduction in feed N yielded an 11 percent reduction in excreted N. According to
Van Kempen and Simmins (1997), reducing the variation of nutrients in feed by using more
appropriate quality control measures would reduce N waste by 13 to 27 percent. Experts believe
'that N losses through excretion can be reduced by 15 to 30 percent in part by minimizing
excesses in diet with better quality control at the feed mill (NCSU, 1998).
'Most plant P occurs in the form of phytate, which is P bonded to phytic acid.
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Plant geneticists have produced strains of corn that contain less phytate-P (i.e., low-phytate com)
and are more easily digested than typical strains, resulting in less P excreted in manure. Allee
and Spencer (1998) found that hogs fed low-phytate com excreted an average of 37 percent less
P in manure, with no adverse effects on animal growth. In. a study by Bridges et al. (1995), two
weight classes of grower-finisher pigs (66.1 and 101.7 kg) were given maize-soybean meal diets
lower in protein and P to determine the reduction in N and P in pig waste when compared with
pigs fed a conventional diet. Total N waste was reduced by 32 percent and 25 percent for the two
weight classes, while total P excretion was reduced by 39 percent and 38 percent, respectively.
The study also modeled the impact of reductions in dietary protein and P over the complete
grower-finisher period using the NCPIG model developed by the North Central Regional Swine
Modeling Committee. Model results showed a reduction of approximately 44 percent in total N
and P excretion compared with the conventional diet, with little impact on the time of
production. In addition, the Federation Europeenne des Fabricants d'Adjuvants pour la
Nutrition Animate in Belgium (FEFANA,1992) calculated that the selection of highly digestible
feedstuffs should result in a 5 percent reduction in total waste.
Advantages and Limitations: Precision feeding results in a higher feed efficiency (less feed used
per pound of pig produced); however, any cost savings are at least partially offset by the cost of
analyzing the nutrient content of feedstuffs. Consumer reaction to use of genetically modified
crops to feed swine has not been determined yet. <
Operational Factors: Precision feeding requires that feed manufacturers have the necessary
equipment and procedures to create precision feeds within specified quality control limits. In
general, feed manufacturers have traditionally limited quality control to measuring N, which
correlates poorly with amino acid content hi feedstuffs (van Kempen and Simmins, 1997).
Precision feeding will also increase the costs and complexity of feed storage at the feeding
operation. .
Demonstration Status: Data on the frequency of use of precision nutrition are not available.
Much of the information available on precision nutrition is derived from small-scale research
experiments at the USDA and universities.
Practice: Multiphase and Split-Sex Feeding for Swine
Description: Multiphase feeding involves changing diet composition weekly instead of feeding
only two different diets during the period from the 45-kg size to slaughter. Multiphase feeding is
designed to better match the diet with the changing nutritional requirements of the growing
animals.
Application and Performance: Feeding three or four diets during the grow-finish period instead
of only two diets will reduce N excretion. According to models such as the Dutch Technical Pig
Feeding Model by van der Peet-Schwering et al. (1993), multiphase feeding reduces N and P
excretion by 15 percent. The modeling results have been confirmed by animal trials that showed
8-3
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a 12.7 percent reduction in N excretion in urine and a 17 percent reduction in P excretion.
Advantages and Limitations: Dividing the growth period into more phases with less spread in
weight allows producers to meet more closely the pig's protein requirements. Also, because gilts
(females) require more protein than barrows (males), separating barrows from gilts allows lower
protein levels to be fed to the barrows without compromising leanness and performance
efficiency in the gilts.
Operational Factors: Multiphase and split-sex feeding require separate feeding areas and pens
for the different types of animals. It is also more costly to produce a different feed every week.
Demonstration Status: The Swine 95 report (USDA APHIS, 1995) showed that 96.2 percent of
grower/finisher operations fed two or more different diets. Of these operations, 63.4 percent
progressed to a different diet based on animal weight, 5.3 percent changed diets based on either
age or the length of time on the feed, and 30.0 percent based diet changes on equal consideration
of weight and time. Of the 96.2 percent of grower-finisher operations that feed more than one
diet, 18.3 percent practiced split-sex feeding. Split-sex feeding is used much more frequently in
medium (2,000-9,999 head) and large operations (10,000+ head) than in small operations (less
than 2,000 head).
Practice: Improved Feed Preparation for Swine
Description: Milling, pelleting, and expanding are examples of technological treatments that
improve the digestibility of feeds. By reducing the particle size, the surface area of the grain
particles is increased, allowing greater interaction with digestive enzymes. NCSU (1998)
reported that the industry average particle size was approximately 1,100 microns and that the
recommended size is between 650 and 750 microns. Expanders and extruders are used mainly to
provide flexibility in ingredient selection and to improve pellet quality rather than to improve
nutrient digestion.
Application and Performance: As particle size is reduced from 1,000 microns to 700 microns,
excretion of N is reduced by 24 percent. Vanschoubroek et al. (1971) reviewed many articles
regarding the effect of pelleting on performance and found that not only did animals prefer
pelleted feed over mash feed, but feed efficiency improved by 8.5 percent and protein
digestibility improved by 3.7 percent witibt pelleted feed.
Advantages and Limitations: Although reducing particle size less than 650 to 750 microns can
increase feed digestibility, it also increases greatly the costs of grinding and reduces the
throughput of the feed mill. Smaller-sized particles can also result in an increased incidence of
stomach ulcers in animals. In some cases, chemical changes resulting from the high temperatures
created in grinding machines may decrease feed digestibility.
8-4
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Operational Factors: A reduction in the particle size of the feed might result in manure with
finer solids particles. This may affect the performance of manure management practices,
including possible effects on the efficiency of manure solid-liquid separators.
Demonstration Status: Data on the frequency of use of feed preparation techniques are not
available.
Practice: Feed Additives for Swine
Description: Enzymes are commonly used in feed to improve the digestibility of nutrients. For
example, plant P is often present in the form of phytate, which is digested poorly in swine,
resulting in most of the P in feedstuffs being excreted in the manure. To prevent P deficiency,
digestible P is added to swine rations, resulting in even more P in the manure. The enzyme
additive phytase has been shown to improve P digestibility dramatically, and can be used to
reduce the need for digestible P additives.
Other enzyme additives facilitate the retention of amino acids and digestive fluids, decreasing the
amount of N excreted. Enzymes such as xylanases, beta-glucanases, and proteases upgrade the
nutritional value of feedstuffs. Xylanases and beta-glucanases are enzymes used to degrade
nonstarch polysaccharides (NSP) present in cereals such as wheat and barley. Swine do not
secrete these enzymes and therefore do not have the capability to digest and use NSP. Because
the NSP fraction traps nutrients that are released only upon partial degradation of the NSP
fraction, addition of xylanase or beta-glucanase or both to cereal-containing diets can result in
improvements in both digestibility and feed efficiency. In addition, supplementing the diet with
synthetic lysine to meet a portion of the dietary lysine requirement is an effective means of
reducing N excretion by pigs. This process reduces N excretion because lower-protein diets can
be fed when lysine is supplemented. The use of other amino acid feed supplements is being
tested.
Application and Performance: Mroz et al. (1994) showed that phytase increases P digestibility
in a typical swine diet from 29.4 percent to 53.5 percent. They also demonstrated that phytase
addition improved the digestibility of other nutrients in the feed such as calcium, zinc, and amino
acids that are bound by phytase. For example, the addition of phytase to a commercial diet
increased the digestibility of lysine by 2 percent while the digestibility of protein improved from
83.3 to 85.6 percent. Van der Peet-Schwering (1993) demonstrated that the use of phytase
reduced P excretion by 32 percent in nursery pigs (a finding similar to the FEFANA [1992]
predictions). Lei et al. (1993) found that feeding pigs 750 phytase units per gram of basal diet
yielded a decrease in fecal P excretion of 42 percent without adverse health effects. This
addition resulted in a linear improvement in phytate-P utilization. Graham and Inborr (1993)
reported that enzyme additions improved the digestibility of protein in a wheat/rye diet by 9
percent.
Beal et al. (1998) used proteases on raw soybeans and observed a significant improvement hi
daily gain (+14.8 percent); feed efficiency, however, was improved by only 4.3 percent. Dierick
8-5
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andDecuypere (1994) saw a substantial improvement in feed efficiency when using proteases in
combination with amylases and beta-glucanases, an improvement larger than that achieved with
each enzyme individually. Studies have shown that protein levels can be reduced by 2 percent
when the diet is supplemented with 0.15 percent lysine (3 pounds lysine-HCl per ton of feed)
without harming the performance of grower-finisher pigs.
Advantages and Limitations: Feed additives, especially synthetic amino acids and enzymes,
increase the cost of feeding. Phytase, for example, was once too expensive to use as a feed
additive. This enzyme can now be produced at lower cost with recombinant DNA techniques.
As technology improves, it is likely that the costs associated with other feed additives will
decrease similarly.
Operational Factors: The level of phytase required in swine feed varies with the age of the
animal. These different levels are likely determined by the development of digestive enzymes
and intestines of the pig, with the younger pig being less developed. Lysine supplements can be
used to achieve even greater reductions in the level of protein in diets, but only if threonine,
tryptophan, and methionine are also supplemented.
Demonstration Status: The use of proteases in animal feeds is not widespread because of
conflicting results from trials. With the advancement of enzyme-producing technology, as well
as a better understanding of the role of enzymes in animal nutrition, proteases and other enzymes
(e.g., pentosanases, cellulase, and hemicellulases, as tested by Dierick, 1989) are likely to play a
greater role in animal nutrition. As their costs come down, the Amino Acid Council foresees an
increased use of synthetic amino acids as a method of reducing N excretion as well as improving
animal performance and decreasing feeding costs.
8.1.1.2 Poultry Feeding Strategies
Poultry operators have traditionally employed feeding strategies that focus on promoting animal
growth rates or maximizing egg production. Feed additives have also been used to prevent
disease and enhance bone and tissue development. As noted in Chapter 4, productivity has
increased dramatically over the past several decades. The decrease in the average whole-herd
feed conversion ratio (pounds of feed per pound of live weight produced) has translated into
reduced feed input per bird produced. Smaller feed requirements can mean decreased manure
output, but, until recently, development of better feeding strategies and advances in genetics have
not focused on manure quality or quantity generated. Environmental Issues associated with
animal waste runoff have compelled the poultry industry to look for improved methods of waste
prevention and management, including feeding regimes that cati reduce the nutrient content of
manure.
Dietary strategies to reduce the amount of N and P in manure include developing more precise
diets and improving the digestibility of feed ingredients through the use of enzyme additives and
genetic enhancement of cereal grains.
8-6
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Practice: Precision Nutrition for Poultry
Description: Precision nutrition entails formulating feed to meet more precisely the animals'
nutritional requirements, causing more of the nutrients to be metabolized, thereby reducing the
amount of nutrients excreted. For more precise feeding, it is imperative that both the nutritional
requirements of the animal and the nutrient yield of the feed are fully understood. Greater
understanding of poultry physiology has led to the development of computer growth models that
take into account a variety of factors, including strain, sex, and age of bird, for use in
implementing a nutritional program. By optimizing feeding regimes using simulation results,
poultry operations can increase growth rates while reducing nutrient losses in manure.
Application and Performance: The use of improved feeds tailored to each phase of poultry
growth has improved productivity significantly. Feed conversion ratios for broilers and turkeys
have decreased steadily over the past several decades. Egg production productivity has also been
boosted as operators have introduced improved nutrient-fortified feed.
Advantages and Limitations: Improved precision in feeding strategies offers numerous
advantages, including reduction of nutrients in animal manure and better feed conversion rates.
Improved formulations are also cost-effective and reduce the probability of wasteful overfeeding
ofpoultry.
Operational Factors: Precision nutrition requires detailed knowledge ofpoultry nutritional
requirements and maintenance of detailed records to ensure that dietary adjustments are
performed in a timely manner to maximize growth potential.
Demonstration Status: The use of precise nutrient formulations has already generated large
increases in productivity in the poultry sector. Many of the poultry operations are under contract
and receive feedstuffs with precise formulations from the integrator. Ongoing research will
likely continue to result in productivity improvements.
. Practice: Use ofPhytase as a Feed Supplement for Poultry
Description: Phosphorus, an essential element for poultry growth and health, is typically added
to poultry feed mixes; However, because poultry are deficient in the enzyme phytase and cannot
break down the protein phytate, much of the P contained in feed cannot be digested (Sohail and
Roland, 1999). Because poultry cannot produce phytase, up to 75 percent of the P contained in
feed grains is excreted in manure (NCSU, 1999).
One feeding strategy used by poultry operators to reduce P levels in manure is to add microbial
phytase to the feed mix.2 This enzyme is produced by a genetically modified fungus, Aspergillus
As noted in Chapter 4, some experts believe phytase should not be provided to poults because of the
enzyme's adverse effect on bone development in turkeys, while other experts believe it will enhance growth.
8-7
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niger. The final enzyme product is usually available in two forms, a powder or a liquid (Miller,
1998). The phytase enzyme reduces P excretion by releasing the phytate-P contained in the cell
walls of feed grains. The released P can then be absorbed by the bird's intestine and used for its
nutrient value. A secondary beneficial effect of using phytase is that manure P content is further
reduced because less inorganic P needs to be added to poultry diets (Edens and Simons, 1998).
Application and Performance: Phytase can be used to feed all poultry. Phosphorus reductions of
30 to 50 percent have been achieved by adding phytase to the feed mix while simultaneously
decreasing the amount of inorganic P normally added (NCSU, 1999).
Advantages and Limitations: Addition of phytase to feed significantly reduces P levels in poultry
manure. The high cost of phytase application equipment has discouraged more widespread use.
Operational Factors: Because phytase is heat-sensitive, it must be added to broiler and turkey
feeds after the pelleting process (NCSU, 1999). The phytase is added by spraying it on the feed.
This can result in uneven distribution and variable doses. Studies have shown that phytase
efficacy is related to calcium, protein, and vitamin B levels in a complex manner. Further,
phytase efficacy can be degraded by excess moisture, which can be a problem if mash (wet) feed
is used for broilers (Miller, 1998). The shelf life of phytase is usually not a problem, because
feed is typically consumed within 2 weeks or less at most operations.
Demonstration Status: Phytase is in use at many poultry operations. Application equipment for
adding phytase to large volumes of feed is undergoing field testing.
Practice; Genetically Modified Feed for Poultry
Description'. Using genetically modified animal feed offers poultry operators another way to
reduce P levels in bird manure. In 1992, a research scientist at the USD A Agricultural Research
Service developed a nonlethal com mutant that stored most of its seed P as P rather than as
phytate, The total P content in the mutant com was the same as that found in conventional com,
except that there was a 60 percent reduction in phytic acid. The P released by the reduction in
phytic acid P becomes available to the consuming animal as inorganic P (Iragavarapu, 1999).
Application and Performance: Genetically modified feed can be used for all poultry types. The
potential for reducing P levels is quite large. One variety of com with a high available P content
has 35 percent of the P bound in the phytate form compared with 75 percent for normal corn
(NCSU, 1999). Recent tests of a new hybrid corn, developed by USDA and the University of
Delaware, demonstrated a 41 percent decrease in P levels in manure. Soluble P levels in waste
decreased by 82 percent, compared with the amount produced by poultry fed a standard
commercial diet (UD, 1999).
Advantages and Limitations:- New hybrid varieties of grain can increase poultry utilization of
plant P. Adding phytase to the modified feed further reduces manure P levels and can eliminate
8-8
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,the need for nutrient supplements. The increased cost of feed and phytase additives might limit
their use.
Operational Factors: The use of genetically modified feed would not differ from the use of
conventional feed, although the increase in available nutrients in the feed would diminish the
need for supplements.
Demonstration Status: Since its discovery hi 1992> the mutant corn has been made available to
commercial companies for further research, development, and commercialization of hybrid
grains.. Some hybrid varieties are currently used; others are in the research or demonstration
stage. As more of these products are developed and prices are lowered, the use of hybrid grains
combined with en2yme additives will likely increase.
Practice: Other Feeding Strategies to Reduce Nutrient Excretion for Poultry
Poultry operators use additives other than phytase to reduce manure nutrient content. These
additives include synthetic amino acids and protease, and they are designed to facilitate more
efficient digestion of N compounds and allow the use of smaller proportions of nutrients in feed
while not adversely affecting animal growth rates and health. Researchers have also
demonstrated that feed enzymes other than phytase can boost poultry performance and reduce
manure production (Wyatt, 1995). Enzymes currently added to barley and wheat-based poultry
feed in Britain and Europe include xylanases and proteases. Currently, the use of additives such
as synthetic amino acids and enzymes could significantly increase feed costs. These costs,
however could be expected to decrease over tune as the technology matures and is more widely
used by animal feed operators.
8.1.1.3 Dairy Feeding Strategies
Feeding strategies to reduce nutrient losses from dairy operations, primarily N and P, are focused
on improving the efficiency with which dairy cows use feed nutrients. A more efficient use of
nutrients for milk production and growth means that a smaller portion of feed nutrients ends up
hi manure. Elimination of dietary excesses reduces the amount of nutrients in manure and is
perhaps the easiest way to reduce on-farm nutrient surpluses (Van Horn et ail., 1996). Reducing
dietary P is the primary practice being used; however, a number of related management strategies
also reduce nutrient levels hi the manure by increasing the efficiency with which dairy cows use
feed nutrients. These strategies include measuring the urea content of milk, optimizing feed crop
selection, and exposing cows to light for a longer period of the day.
Practice: Reducing Dietary Phosphorus (P) for Dairy Cattle
Description: Reducing the level of P in the diets of dairy cows is the primary and most important
feeding strategy for reducing excess nutrients given (1) P's central role as a limiting nutrient hi
many soils, (2) evidence indicating that dairy operators, as a whole, are oversupplying P hi dairy
diets, and (3) the N-P imbalance hi cow manure, which favors reductions of P to produce a more
• 8-9
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balanced fertilizer. Reducing the amount of P in dairy diets has also been shown to reduce
production costs and increase overall profitability.
The latest edition of the National Research Council's (NRC) nutrient requirements for dairy cows
recommends dietary P levels of 0.36 to 0.40 percent of dry matter for high-producing dairy cows
in lactation (NRC, 1989). Dietary P in excess of these requirements has been shown to have no
beneficial effect on animal health or production. Most excess P passes through the cows'
systems and is excreted as manure, which is later applied to land. Rations, however, typically
average 0.50 percent P or more (Knowlton and Kohn, 1999). Supplemental feeding of dicalcium
phosphate-often the second most expensive component in dairy cow diets-is the usual practice
by which a dairy cow's rations achieve this level. A number of studies have addressed the
adequacy of current dietary P recommendations. These studies include Steevens et al., 1971;
Tamminga, 1992; McClure, 1994; and Chase, 1998.
Application and Performance: This practice should be applicable to all dairy operations. The
amount of manure P resulting from a given level of dietary P is estimated using the following
equation (Van Horn, 1991):
Manure P = 9.6 +0 .472*(rntake P) + 0.00126*(rntake P)2 - 0.323*Milk
Manure and intake P are measured in grams, and milk production is measured in kilograms.
Based on this formulation, assuming that each lactating cow produces 65 pounds of milk a day,
Table 8-1 quantifies reductions in manure P resulting from reduced P intake (Keplinger, 1998).
Four scenarios are considered: a 0.53 percent P diet, which is considered the baseline, and three
reduced P diet scenarios. Comparing the 0.40 percent scenario against the baseline, P intake
during lactation is reduced by 25 percent, while manure P is reduced by 29 percent. During the
entire lactation period, manure P is reduced by 14.63 pounds per cow from the baseline level of
50.45 pounds per cow. For the entire year (lactation and nonlactation periods), manure P per
cow is reduced by 27 percent.
Table 8-1. Per Cow Reductions in Manure P Resulting from
Reduced P Intake During Lactation
Percentage of P
in Diet
0.53
0.49
0.46
0.43
0.40
Daily
P Intake
(lb)
0.265
0.245
0.230
0.215
0.200
Manure?
Ob)
0.165
0.150
0.139
0.128
0.117
Manure P (lb)
During
Lactation
50.5
45.8
42.4
39.1
35.8
Entire
Year
55.1
50.4
47.0
43.7
40.4
Reduction from Baseline (0.53%)
Amount
(lb)
0.0
4.7
8.1
11.4
14.6
During
Lactation
0
9
16
23
29
Entire
Year
0
8
15
21
27
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Advantages and Limitations: Supplemental feeding of dicalcium phosphate to dairy cows
represents a substantial expense to dairy farmers-the second most expensive nutrient in a herd's
mixed ration (Stokes, 1999). The economic advantages of reducing supplemental P, based on a
study on the Bosque River watershed of Texas (Keplinger, 1998), suggest that a dairy operator
who adopts a 0.40 percent P diet compared with the baseline 0.53 percent diet would save $20.81
per cow annually. A survey of scientific literature on the subject reveals no adverse impact on
either milk production or breeding from reducing dietary P to NRC-recommended levels.
Another advantage to producers is the impact of reduced manure P on land application practices.
Many states incorporate a P trigger in manure application requirements. For example, in Texas,
state regulation requires waste application at a P rate (versus an N rate) when extractable P in the
soil of an application field reaches 200 parts per million (ppm). Applying manure with a lower P
concentration would slow and possibly eliminate the buildup of P in application fields, thereby
delaying or eliminating the need to acquire or transform more land into waste application fields.
When manure is applied at a P rate, greater quantities can be applied if it contains a lower P
concentration. Thus, application fields would require less chemical N, because manure with
lower P concentrations is a more balanced fertilizer, hi addition, reduced land requirements for
waste application fields would represent substantial savings to dairy producers in cases in which
a P application rate is followed.
Operational Factors: It is possible that factors such as climate, temperature, and humidity, as
well as operation-specific factors, influence the effectiveness of steps taken to reduce dietary P;
however, there are no published studies that address this issue. Dairy cows, for instance, are
more prone to disease in moist climates and suffer heat stress in hot climates. Average milk
production per cow varies greatly across geographic regions of the United States-averaging
21,476 pounds in Washington state versus only 11,921 pounds in Louisiana (USDA, 1999).
Because dairy cow productivity and health are influenced by climate, it is likely that climate may
also influence the effectiveness of nutrient reducing feeding strategies, particularly those which
depend on productivity gains. The magnitude and even the direction of the influence of factors
such as temperature, humidity, and the like on nutrient-reducing feeding strategies, however,
have not been established.
Demonstration Status: Dairy rations typically average 0.50 percent P or more (Knowlton and
Kohn, 1999), much higher than the NRC recommendation of 0.40 percent. A survey of milk
producers in north Texas by a milk producers' organization indicated dietary P averaged 0.53
percent. A 1997 survey of professional animal nutritionists in the mid-south region (Sansinena et
al., 1999), indicates nutritionists' recommendations of dietary P averaged 0.52 percent, or 30
percent higher than the high end of NRC's current recommendation. -Survey respondents cited
several reasons for recommending final ration P in excess of NRC standards: "Almost half of the
respondents (15 of 31) expressed a belief that lactating cows require more P than suggested by
the NRC" (Sansinena et al., 1999). The next most prevalent reason given was that a safety
margin was required. Justifications for the safety margin included a lack of confidence in
published ingredient P values and concern for variable P bioavailability in feed ingredients.
Professional opinion also suggests that dietary P in dairy cow diets averages around 0.52 percent
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throughout the nation, although this percentage may be declining. Because of the heightened
awareness of both the environmental benefits and the cost savings attainable by reducing P in
dairy cow diets, some operators have adopted the NRC recommendation. Recent articles in 'dairy
trade magazines have recommended adoption of the NRC standard for both environmental and
economic benefits.
Practice: Milk Urea N Testing for Dairy Cattle
Description: There have been significant developments recently in the use of milk urea N (MUN)
as a method for testing and fine-tuning dairy cow diets for protein feeding. Measured MUN
concentrations are used as a proxy for the nutritional well-being of the cow.
Research has shown that mean MUN concentration levels from a group of cows should fall into
specific ranges. By comparing the results of MUN tests with these ranges, the tests can be used
as a monitoring tool to evaluate a herd's protein nutritional status. For cows fed at optimal dry
matter intake, expected mean values of MUN concentrations range from 10 to 14 milligrams per
deciliter (mg/dL) (Ferguson, 1999; Jonker et al., 1998). Field studies of MUN levels of dairy-
herds in Pennsylvania (using a very large sample-312,005 samples) have reported average MUN
concentrations of 14 ing/dL (Ferguson, 1999). Implicit in this level is that even allowing for the
inherent large variability of MUN testing, the diets of some herds contain excess MUN levels
that have no economic value; this also suggests that N in manure can be reduced by reducing
excess N in dairy diets. The importance of reducing dietary protein levels is highlighted in a
study (Van Horn, 1999) that estimates that for every 1 percent reduction in dietary protein,
excretion of N may be reduced by 8 percent.
Application and Performance: This practice should be applicable to all dairy operations. The
elimination of excess dietary protein with the use of the MUN test to evaluate protein levels in
dairy cow feeds could reduce N levels in manure by 6 percent (Kohn, 1999). In addition, further
methods to improve N utilization in dairy cows and raise the efficiency of feed delivery may be
revealed by MUN testing.
Advantages and Limitations: Through MUN testing and the evaluation of other variables,
farmers can identify which cows are eating too much protein, and fine-tune diets, thereby
reducing N output in manure. Advantages of MUN testing are the possibilities of reducing ration
costs by eliminating excess protein and improving the efficiency of feed delivery (Kohn, 1999).
A disadvantage of animal group feeding strategies is that they become more difficult to set up
and manage as group size decreases. The cost-effectiveness of custom feeding individual cows is
as yet unproven. .
Operational Factors: The large variability within and between herds and breeds of cows limits
the usefulness of MUN testing, but it does not reduce the test's important role as a monitor of
ration formulation.
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Demonstration Status: This practice is primarily at the research stage and has not become
widespread.
Practice: Diet Formulation Strategies for Dairy Cows
Description: Diet formulation strategies have received new examination. Alternative diet
formulations to the NRC recommendations-notably the Cornell Net Carbohydrate and Protein
model (CNCPS) (Sniffen et al., 1992)-that are more complicated than the NRC
recommendations have been developed and they suggest feeding about 15 percent less protein to
a herd at the same level of production for certain conditions (Kohn, 1996). Evaluations of the
CNSPS model's performance have been mixed, and further research is needed. Thus, the
CNCPS is not currently recommended for routine diet formulation.
Theoretically, protected amino acid supplements have the potential to be part of an important
strategy in increasing the efficiency of protein use by dairy cows, thereby reducing N losses. If
amino acid supplements can be made effectively for dairy cows (avoiding rumen-associated
problems), they could replace large portions of a dairy cow's protein intake, in theory, protected
amino acid supplements could significantly reduce N intake and hence N levels in manure. In
practice, the benefits of using protected amino acid supplements may not be as dramatic because
the need to balance diet formulations may create limitations.
Application and Performance: This practice should be applicable to all dairy operations. Some
evaluation of the alternative diet formulation suggested by the CNCPS implies a significant
increase in .milk production (from 24,100 pounds/cow per year to more than 26,000 pounds/cow
per year) and a large reduction in N excretion (of about one-third) (Fox et al., 1995). More recent
evaluations using two different large data sets (Kalscheur et al., 1997; Kohn et al., 1998) present
mixed results, with the CNCPS performing better in some aspects and the NRC
recommendations in others. Thus, results of the CNCPS evaluation should be considered
preliminary. In theory, the use of protected amino acid supplements has great potential to
improve nutrient efficiency. A typical lactating cow is assumed to require 1.1 pounds per day of
N intake; by successfully substituting protected methionine and lysine for feed protein, this N
intake and resulting manure N could be dramatically reduced (Dinn et al., 1996), but this research
is preliminary.
Advantages and Limitations: Alternative diet formulations could improve nutrient efficiency.
Information on limitations is unknown at this time, and EPA is continuing research in this area.
Operational Factors: The cost of preparing and storing multiple feed stuffs limits the use of this
practice to the number of diets that the operator feels justifies the additional expense. Additional
research on this practice is needed.
Demonstration Status: This practice is primarily at the research stage and has not become
widespread.
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Practice: Animal Feed Grouping for Dairy Cows
Description: Grouping strategies offer another method of realizing gains in nutrient efficiency.
When grouping does not occur and the whole herd receives the same diet, cows may receive
suboptimal diets and nutrient export to manure may be greater. Using grouping strategies to their
greatest effect to improve nutrient efficiency would entail individualized diets. Feeding
strategies already reviewed, such as the MUN concentration test, can be used in conjunction -with
grouping strategies or individual diets.
Application and Performance: This practice should be applicable to all dairy operations.
Grouping strategies have been shown to reduce nutrient intakes and manure nutrients. When all
the lactating cows are fed together according to current recommendations, they consume 7
percent more N and P, and 10 percent more nutrients are excreted in manure, compared with the
individualized feeding strategy. Half of the gains of individualized diets could be achieved vrith
two groups (Dunlap et al., 1997).
Advantages and Limitations: This practice could improve nutrient efficiency. Information on
limitations is unknown at this time, and EPA is continuing research in this area.
Operational Factors: As noted under diet formulation strategies, the cost of preparing and
storing multiple feedstuffs limits the use of this practice to the number of diets that the operator
feels justifies the additional expense. Additional management input is also required in separating
the animals into groups.
Demonstration Status: Dairy operations currently employ a range of grouping strategies (from
no grouping to individual diets) to improve the efficiency of feed nutrients.
Practice: Optimizing Crop Selection
Description: Optimizing crop selection is another potential strategy for reducing nutrient losses
in combination with dairy diets to meet annualized herd feed requirements with minimal nutrient
losses. In whole-farm simulation of various crop strategies (corn silage, alfalfa hay, and a 50:50
mixture) the 50:50 mixture was judged to have performed best (when evaluated by N losses per
unit of N in milk or meat) (Kohn et al., 1998). Converting dairy operations from confined to
pasture operations is also considered a strategy for reducing nutrient loss on a per cow or
operation basis. Kohn's model, however, found that a strategy of grazing versus confinement for
lactating cows produced higher N loss per unit of milk produced because the decline in milk
production was greater than the decline in manure nutrients (Kohn et al., 1998).
Application and Performance: This practice should be possible at operations that have sufficient
land. In simulation of crop selection strategies involving whole-farm effects, mixed alfalfa hay
and corn silage (50:50) was judged the best strategy for rninimizing nutrient flows from the farm.
N losses were rrdnimized to 2.9 units for every unit of N in meat or milk, compared with a loss of
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3.5 units in the corn-based strategy, a 21 percent reduction (Kohn, 1999). Phosphorus
accumulations did not tend to vary among the different strategies.
Advantages and Limitations: Optimal crop selection based on whole-farm effects suggests that
the strategy that was most nutrient efficient in terms of N loss per unit of N in meat and milk is
also the strategy that gains the most productivity from N; this strategy might, therefore, be the
most cost-effective (Kohn et al., 1998). A grazing (versus confinement) strategy may or may not
be cost-effective depending on the structure pf individual dairy operations.
Operational Factors: Unknown at this time.
Demonstration Status: This practice is primarily at the research stage and has not come into
widespread use. -
Practice: Increasing Productivity
Description: The literature suggests that there are several feeding strategies that focus on
increasing productivity as a route to nutrient efficiency. While the focus is on increased milk
production, an important associated benefit of these strategies is that they result in greater milk
production per unit of nutrient excreted. One approach involves exposing dairy cows to light for
longer daily periods of the day through the use of artificial lighting. A longer daily photoperiod
(18 hours light/6 hours dark) increases milk yields relative to those of cows exposed to the
natural photoperiod (Dahl et al., 1996).
Application and Performance: This practice should be applicable at all operations that confine
their animals. The artificial lighting technology to extend the, daily photoperiod of dairy cows to
18 hours a day has been shown to be effective in increasing the nutrient efficiency of the farm.
For an increase in milk production of 8 percent the herd's feed nutrients would be required to
increase by only 4.1 percent, and N and P excretions would rise by only 2.8 percent when
compared versus a typical herd.without artificial lighting (Dahl et al., 1996,1998).
Advantages and Limitations: The artificial lighting technology is expected to be cost-effective. It
is estimated that the initial investment in lighting can be recouped within 6 months. One
observed advantage of milking three times a day rather than twice a day is that it reduces stress
on the herd (Erdman and Varner, 1995). Because of the increased labor involved, the economic
advantage of milking three times a day is variable and dependent on the individual farm (Culotta
and Schmidt, 1988).
Operational Factors: To use this practice many dairy operations would need to install and
operate additional lights.
Demonstration Status: This practice is primarily at the research stage and has not come into
widespread use.
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8.1.2 Reduced Water Use and Water Content of Waste
This section presents practices that reduce the water content in the waste stream. The production
of a drier waste can be accomplished by three methods: (1) handling the waste in a dry form, (2)
reducing the use of water at the AFO, or (3) separating the solid fraction of the waste from the
liquid fraction. Most poultry operations currently handle their waste hi a dry form, and this
section does not apply to them. .
Practice: Dry Scrape Systems and the Retrofit of Wet Flush Systems
Description: Scraper systems are a means of mechanically removing manure, and they can be
used to push manure through collection gutters and alleys similar to those used in flush systems.
For best results, scrapers should have a minimum depth of 4 inches in open gutters and 12 to 24
inches in underslat gutters (MWPS, 1993).
Retrofitting a wet flush system with a dry scrape system involves reconstructing the existing
manure handling equipment within a livestock housing structure. A scraper blade replaces
flowing water as the mechanism for removing manure from the floor of the structure.
In flush systems, large volumes of water flow down a sloped surface, scour manure from the
concrete, and carry it to a manure storage facility. There are three basic types of flush systems: '
underslat gutters, narrow-open gutters, and wide-open gutters or alleys. Underslat gutters are
used primarily in beef confinement buildings and swine facilities in which animals are housed on
slats to prevent disease transmission as a result of animals coming into contact with feces.
Narrow-open gutters are typically less than 4 feet wide and are used predominately in hog
finishing buildings. Wide-open gutters or alleys are most often seen in dairy freestall barns,
holding pens, and milking parlors. The water used in a flush system can be either fresh or
recycled from a lagoon or holding basin (Fulhage et al., 1993; MWPS, 1993).
Application and Performance: Removing manure with a scraper is appropriate for semisolid and
slurry manure, as well as drier solid manure. The flush system is an appropriate means of
removal for both semisolid and slurry manure. Retrofitting a flush system to a scraper system
appears to be most feasible in underslat gutters and wide alleys. A major concern to be addressed
is the discharge area of the scraper. Existing collection gutters, pumps, and pipes used in a flush
system will likely be inadequate for handling the undiluted manure product.
Replacing a flush system with a dry scrape system dramatically reduces the amount of water used
in manure handling and also reduces the tonnage of manure by decreasing dilution with water.
There are several options for storing manure from a scrape system, including prefabricated or
formed storage tanks, from which contaminants are less likely to seep.
Retrofitting a flush system with a scrape system will not treat or reduce pathogens, nutrients,
metals, solids, growth hormones, or antibiotics. The concentrations of these components will
actually increase with the decrease in water dilution..
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Advantages and Limitations: In a building with a scrape system, the manure removed from the
livestock housing area is in slurry or semisolid form (depending on species) and no water need be
added. Compared with a wet flush system, the resulting manure product has a greater nutrient
density and increased potential for further treatment and transportation to an area where the
manure product is needed as a fertilizer. A large lagoon is usually necessary for storing and
treating flush waste and water; handling manure in a drier form, on the other hand, significantly
decreases the volume and tonnage of the final organic product. Although this is an important
advantage when it is necessary to transport manure to areas where there is an increase in
available land base, it can be a disadvantage in that an irrigation system would not be able to
transport the thicker slurry that results from the use of a scrape system.
The greater volume of contaminated water and waste created in a flush system generally dictates
that storage in a large lagoon is required. There are more options for storing manure removed
with a scrape system. These storage alternatives may be more suited to practices that reduce
odors (e.g., storage tank covers), more appropriate for areas with karst terrain or high water
tables, and more aesthetically desirable.
The drawbacks of using a scrape system rather than a flush system include an increased labor
requirement because more mechanical components need maintenance, a higher capital outlay for
installation, an increased requirement for ventilation, and less cleanliness. Using a flush system
to remove manure results in a cleaner and drier surface with less residual manure and less in-
house odor, thus creating a better environment for livestock. Furthermore, alleys can be flushed
without restricting animal access. As mentioned above, the discharge area of the scraper is a
concern. Existing pumps and pipes may be unable to handle the undiluted manure. Moreover, a
completely new manure storage structure might be needed (Vanderholm and Melvin, 1990).
Operational Factors: Both the scrape and flush systems have disadvantages when used in open
barns during winter months, but a scrape system is more likely to function properly at lower
temperatures.
If alleys are straight with continuous curbs, alley scrapers can usually be installed, but alley
lengths of up to 400 feet in dairy freestall barns may make installation of scraping systems
impractical. Scrapers work best when they can be. installed in pairs of alleys so the chain or cable
can serve each and form a loop. It might be necessary to cut a grove into the concrete alley for
the chain or cable to travel in. The decision of whether to cut a channel or let the chain rest on
the pavement is best left to the manufacturer. It should be noted that maintenance requirements
associated with the chain and cable will likely be high because of corrosion caused by continuous
contact with manure. Hydraulic scrape units that operate on a bar and ratcheting blade are also
available (Graves, 2000).
Demonstration Status: The use of scrape systems and the practice of retrofitting a flush system
are not common in the livestock industry. Inquiries regarding the use of this practice have been
made to manure management specialists, agricultural engineers, and manufacturers of scraper
systems. Very few professionals indicated that they had any experience in the area or were aware
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of the practice being used. Those professionals willing to comment on the implications of
retrofitting seemed to believe that it would be most feasible and advantageous on dairies (Graves,
2000; Jones, 2000; Lorimor, 2000; Shih, 2000).
Practice: Gravity Separation of Solids
Description: Gravity settling, separation, or sedimentation is a simple means of removing solids
from liquid or slurry manure by taking advantage of gravitational forces. The engineering
definition of a settling or sedimentation tank is any structure that is designed to retain process
wastewater at a horizontal flow rate less than the vertical velocity (settling rate) of the target
particles.
In agricultural applications, gravity settling is a primary clarification step to recover solids at a
desired location where they can be managed easily, thereby preventing those solids from
accumulating in a downstream structure where they would be difficult to manage. A wide range
of gravity separation practices are used in agriculture, including sand and rock traps, picket dams,
and gravity settling basins designed to retain 1 to 12 months' accumulation of solids.
Settling tanks can be cylindrical, rectangular, or square. Agricultural settling tanks have been
made with wood, metal, concrete, and combinations of materials. Some are earthen structures.
In agriculture, gravity separation is sometimes accomplished without a recognizable structure,
including techniques such as a change in slope that allows particles to settle when the liquid
velocity drops.
The critical design factor in sedimentation tanks is surface overflow rate, which is directly related
to the settling velocity of particles in the wastewater (Loehr, 1977). Faster settling velocities
allow for increased surface overflow rates, while slower settling velocities require decreased
overflow rates to remove settleable particles. In "ideal" settling, the settling velocity (Vs) of a
particle is equal to that particle's horizontal velocity (VH), where
VH = Q/DW
Q is the flow through the tank
D is the tank depth
W is the tank width
The American Society of Agricultural Engineers (ASAE, 1998) has defined several types-of
gravity separation techniques:
• Settling Channels: A continuous separation structure in which settling occurs over a
defined distance in a relatively slow-moving manure flow. Barries and porous dams may
be used to aid separation by further slowing manure flow rates. Solids are removed
mechanically once liquids are fully drained away.
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• Settling Tank: A relatively short-term separation structure, smaller in size than a settling
basin. The liquid is allowed to fully drain away for solids removal by mechanical means.
Settling Basin: A relatively long-term separation structure, larger in size than a settling
tank. Solids are collected by mechanical means once the liquids evaporate or have been
drained away.
Application and Performance: Gravity separation is relatively common in the United States.
Separation is used to reduce clogging of downstream treatment or handling facilities. Reduced
clogging means improved lagoon function and better wastewater treatment. Most beef feedlots
in the Midwest and Great Plains use gravity separation ponds to collect solids from rainfall
runoff, thus improving the function of runoff collection ponds. Gravity separation basins are used
across the country on hog farms to reduce solids accumulation in tanks or lagoons they discharge
to. It is likely that more dairies with flush systems use gravity settling for solids recovery rather
than mechanical separators to preserve lagoon capacity. ,
Table 8-2 shows the substantial range of treatment efficiencies for gravity settling of manure.
The performance of a gravity separation basin depends on the design goal and ability of the
operator to maintain the system in design condition. Performance will vary with animal type,
animal feed, dilution water, flow rate, percent of capacity already filled with solids, temperature,
and biological activity. The data ranges in Table 8-2 may be explained in part by the time span
separating the studies. More recent studies show reduced solids recovery from swine manure.
This may be partly due to the fact that animal diets have changed over the years, with feed more
digestible and more finely ground these days. Further, feed is ground to different particle sizes
that have different settling characteristics, thus potentially affecting separation basin
performance. In addition, ruminants are fed materials that have different settling characteristics
than those fed to nonruminants. Process variables such as overflow velocities are seldom
reported in the literature, but they are important determinants of separation basin performance.
Extra water from processing or precipitation and already settled material will increase the flow
rate across a settling basin, reducing settling time and solids capture. Li many agricultural
settling basins, biological activity resuspends some settled materials which then pass through the
separator. At best, one can conclude from these data that gravity settling can recover in swine
wastes a larger percentage of total solids (TS), volatile solids (VS), and total nitrogen (TN) than
another separation technique reviewed for the practice, mechanical solid-liquid separation, that
follows in this chapter.
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Table 8-2. Performance of Gravity Separation Techniques
Recovered in Separated Solids, Percent
Swine (Moser et al.,
1999)
Beef (Edwards et
al.,1985; Lorimore et al.,
1995) and Daiiy (Barker
and Young, 1985)
TS
39-65
50-64
ys
45-65
NA
TN
23-50
32-84
PA
17-50
20-80
K
16-28
18-34
COD
25-55
NA
TS=Total solids; VS=volatile solids; TN=total nitrogen; P2O5=pyrophosphate; K=potassmm, COD=chemical
oxygen demand.
Because of short return times, pathogen reduction through settling is minimal; however, settling
might reduce worm egg counts. No information is available on growth hormones in manure or
on how settling might affect growth hormones that may be found in manure. Degradation of
antibiotics usually hinders their detection in manure, and no information is available on the effect
of settling on antibiotics hi manure.
Taiganides (1972) measured 80 to 90 percent recovery of copper, iron, zinc, and phosphorus with
settled swine sblids. The study also reported that 60 to 75 percent of the sodium, potassium, and
magnesium settled and was recovered.
Advantages and Limitations: The mam advantage of gravity settling is the relatively low cost to
remove solids from the waste stream. Recovering solids prevents the buildup of those solids in
ditches, pipelines, tanks, ponds, and lagoons. Dairy solids consist mostly of fiber and can be
composted and recycled as cow bedding material, or they can be composted and sold as a soil
amendment Swine solids are finely textured, hard to compost aerobically, and rapidly degraded
to odoriferous material if handled improperly. Beef solids collected from lot runoff can become
ddoriferous if left in a separation basin, but they can be composted for sale to crop farms,
nurseries, or soil products companies.
Collected solids are a more concentrated source of nutrients than the separated liquid, resulting in
decreased hauling costs per ton of nutrient. The separated liquid has a reduced nutrient content
and can be applied to a smaller acreage than the original material.
Disadvantages of solids separation include the need to clean out the separator, the potential odor
emitted from the basin, the odor produced by solids removed from the basin, and attraction of
insects and rodents to the separated solids. Additional costs are incurred when the solids and
liquids from pig manure are managed separately.
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Operational Factors: Solids separators do not function if they are frozen or experience
horizontal flow rates higher than the solids settling rate. Solids tend to separate better at warmer
temperatures.
Demonstration Status: Gravity separation is the most common solids separation technique in use
in the United States.
Practice: Mechanical Solid-Liquid Separation
Description: Solids-liquid separation is used to recover solids prior to their entry into
downstream liquid manure facilities. Solids recovery reduces organic loading and potential
accumulation of solids and improves the pumping characteristics of animal manure. Mechanical
separation equipment is used to reduce the space required for separation, to produce a consistent
separated solid product amenable to daily handling, to produce a liquid product that is easily
pumped for spreading, or to recover specific particle sizes for other uses such as bedding.
Mechanical separation equipment is readily available for animal wastes. Mechanical separators
include static and vibrating screens, screw press separators, rotary strainers, vacuum filters,
centrifugal separators, belt filter presses, and brushed screen/roller presses. Static screens are the
most popular mechanical separators because they are inexpensive to buy, install, and operate.
All other mechanical separation techniques are less common.
Static screens are usually mounted above grade on a stand to allow solids accumulation beneath.
Barn effluent is typically pumped up to the screen, where the liquids pass through while the
solids collect on the screen surface. Screens are typically inclined, causing accumulating solids
to slide down from the screen toward collection. There are multiple configurations with different
screen designs, screen materials, screen opening spacing, influent distribution, post-use
washdown, and additional pressing of separated solids.
Vibrating screens are flat or funnel-shaped screens supported on springs and oscillated by an
eccentric drive. The vibrations cause, the solids to move from the screen for collection.
With screw presses, manure is pumped to the base of a turning open-flight auger that goes
through a screen tube made of welded wire, wedge wire, perforated metal, or woven screen
material. Solids collect on the screen, forming a matrix as the auger advances them. A
tensioned opening restricts the flow of materials up the auger and out from the tube. The
retained material is squeezed by the auger against the screen tube and tensioned opening until it
overcomes the tension and exits. The matrix acts as a filter allowing the collection of finer
particles than are collected by other types of screens. The auger wrings liquid from the separated
solids by forcing material against the plug of material held by the tensioned opening and screen
tube.
A rotary strainer is a slowly rotating, perforated cylinder mounted horizontally. Waste flows by
gravity onto the cylinder at one end, where solids are scraped from the cylinder surface and
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moved to the exit end. Liquids pass through the screen for collection and removal (ASAE,
1998). Vacuum filters are horizontally mounted, rotating perforated cylinders with a cloth fiber
cover. A vacuum is used to draw liquids from the wastewater. Wastewater flows onto the
cylinder surface, liquids pass through the screen, and solids are scraped from the cloth at a
separation point (ASAE, 1998).
A centrifugal separator, or centrifuge, is a rapidly rotating device that uses centrifugal force to
separate manure liquids from solids. One type, a relatively low-speed design, uses a cylindrical
or conical screen that can be installed vertically or horizontally. Manure is fed into one end, and
solids are then contained by the screen, scraped from it, and then discharged from the opposite
end. The liquid passes through the screen. A second type, a higher-speed decanter, uses a
conical bowl in which centrifugal force causes the denser solids to migrate to the bowl exterior
where they are collected. Less dense liquids are forced to the center for collection ASAE, 1998).
A belt press is a roller and belt device in which two concentrically running belts are used to
squeeze the manure as it is deposited between the belts. The belts pass over a series of
spring-loaded rollers where liquids are squeezed out or through the belt, and remaining solids are
scraped off at a belt separation point (ASAE, 1998).
Brush screen presses are rectangular containers with four vertical sides and a bottom consisting
of two half-cylindrical screens lying side by side to provide two stages of separation. Within
each screen rotates a multiple-brush and roller assembly that sweeps the manure across the
screen. Manure is pumped into one side of the separator. The liquids are forced through the
screen by the brush/roller while the solids are retained by the screen and pushed from the
separator on the opposite side (ASAE, 1998).
Application and Performance: Mechanical separation is used to reduce clogging of downstream
treatment or handling facilities. The use of this practice to preserve lagoon capacity by
separating solids is relatively common among dairies using flush manure collection. Reduced
clogging means improved lagoon function and better wastewater treatment. Mechanical
separation of solids from manure, however, is relatively rare because of the added costs.
Table 8-3 shows the range of treatment efficiencies for the mechanical separation of manure.
These systems do not perform as well as gravity separation, but they produce a more consistent
product delivered as a solid for easy collection. Most manufacturers and owners are less
concerned about the percentage of recovery or the properties of the recovered material than they
are about the total solids concentration of the separated solids. Performance will vary with
animal type, animal feed, dilution water, flow rate, percent of capacity already full of solids,
temperature, and biological activity. In general, pig manure has finer solids than cow manure,
and recovery of pig manure constituents is in the low end of the ranges in Table 8-3, whereas
cow manure constituent recovery is in the upper portion of the range.
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Table 8-3. Summary of Expected Performance of Mechanical Separation Equipment
Separation Technique
Stationary screen
Vibrating screen
Screw press
Centrifuge
Roller drum
Belt press/screen
Recovered in Separated Solids, Percent
TS
10-25
10-20
20-30
40-60
20-30
40-60
vs
10-25
10-20
20-30
40-60
20-30
40-60
TN
5-15
10-20
10-20
20-30
10-20
30-35
P205
10-20
8-15
20-30
25-70
10-15
15-20
COD
5-20
10-20
20-40
30-70
10-25
30-40
Pathogen reduction through mechanical separation is negligible. No information is available on
growth hormones in manure or on the effect of mechanical separation on growth hormones that
may be found in manure. Degradation of antibiotics usually hinders their detection in manure,
and no information is available on the effect of mechanical separation on antibiotics in manure.
No significant information was found on the effect of mechanical separation on heavy metal
content of either the solids or the liquids. Work in gravity separation suggests that metals are
associated with fine particle sizes that would pass with the liquids through mechanical
separation.
Static (stationary) screens are most commonly used for separating solids from dilute solutions
with solids concentrations of 5 percent or less. The more dilute the solution, the more likely that
discrete particles will be collected on the screen because there is less particle-versus-particle
interference. The dilute solution also washes finer particles from larger, retained particles and
through the screen.
Vibrating screens are used for separating solids from dilute solutions with solids concentrations
of 3 percent or less. Vibrating screens will generally process more flow per unit of surface area
than static screens because the vibrating motion moves the solids from the screen. Vibrating
screens are more sensitive than static screens to variations in solids content and wastewater flow
(Loehr, 1977).
Static screens and vibrating screens usually collect 10 to 15 percent of the total solids from
manure. An owner generally selects a screen that will not easily clog, or blind (i.e. one with
larger screen spacing), instead of choosing an optimized screen and feed pump to avoid both
screen blinding, when the slurry thickness changes, and the creation of a soggy solids pile.
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Screw presses can handle thicker materials than most separators, and are used to separate
manures that have between 0.5 and 12 percent total solids. Chastain et al. (1998) noted,
however, that a screw press did not separate well unless the total solids content of the waste was
above 5 percent. Because screw presses first allow the solids to form a matrix and catch fine .
solids, the percent solids recovery is generally greater than for other solids separators. The screw
press is designed to produce drier solids (up to 35 percent). Solids recovery is dependent on the
screen tube openings and the setting of the retaining tension. The higher the tension is set, the
harder the screw squeezes the separated material, and the more solids are forced out through the
screen. Tighter settings for drier solids may significantly affect the useful life of both auger and
screen.
Belt presses are expensive, require a trained operator, operate best with chemical addition, and
cannot process rocks and barn parts found in manure. With or without chemical addition,
however, they can do a good job of separating 40 percent or more of the total solids.
Nevertheless, the cost of belt presses, plus the extremely high cost of maintenance and the need
for continuous operator presence, makes their use'problematic.
The primary advantage of centrifugation over other separators appears to be in the reduction of
total P, but centrifugation is also clearly more efficient than screening for removal of all
constituents. Managed by trained operators, centrifuges will recover over 60 percent of the total
solids. Nevertheless, the large capital cost, the need for trained operators, and the high
maintenance costs have made this equipment unpractical for farm use.
Advantages and Limitations: The main advantages of mechanical separation are the consistent
level of solids removal from the waste stream and the delivery of separated solids at a recovery
location. Recovering solids prevents the buildup of those solids in ditches, pipelines, tanks,
ponds, and lagoons. Dairy solids, which consist mostly of fiber, can be composted and recycled
as cow bedding material. Dairy solids have also been composted and sold as a soil amendment.
Swine solids are finely textured, hard to compost aerobically, and rapidly degraded to odoriferous
material if handled improperly.
Collected solids are a more concentrated source of nutrients than the separated liquid, resulting in
decreased hauling costs per ton of nutrient. The separated liquid has a reduced nutrient content
and can be applied to a smaller acreage than the original material.
Disadvantages of solids separation include operation and maintenance requirements, potential
odor production from collection basins and separated solids, and attraction of insects and rodents
to the separated solids. Additional costs are incurred when the solids and liquids in swine
manure are managed separately.
Operational Factors: Mechanical solids separators do not function if the manure or the face of
the machine is frozen, but they can operate under a wide variety of other conditions.
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Demonstration Status: Mechanical solids separation is being used at thousands of dairies and
perhaps several hundred hog farms. Regarding specific technologies, static screens are most
commonly used, whereas vibrating screens and rotary strainers are seldom used on farms today.
Vacuum filters are infrequently used on farms because inorganic materials such as rocks and
metal bits tend to rip the filter fabric. High capital and operating costs have limited farm use of
centrifugal separators. Brash screen presses may occasionally be found on farms, but the low
throughput rate has limited its use. Screw presses are in use at a few hundred dairy farms, but at
a very limited number of swine farms in the United States.
Practice: Two-Story Hog Buildings
Description: The two-story, High-Rise™ hog building design (Menke et al., 1996) integrates
manure collection, storage, and treatment in a single, enclosed facility. The building is designed
to pen approximately 1,000 head of hogs on the second floor of a two-story building, with a dry
manure collection and storage system on the first (ground) level. The second floor features solid
side walls and totally slatted floors. The manure falls through the slats to the first floor area,
which is covered with 12 to 18 inches of a dry bulking agent such as sawdust, oat or wheat straw,
com fodder, or shredded newspaper. The design includes sliding doors on the ground level to
allow for tractor and loader access. 5
The building's unique, two-fold ventilation system maintains superior air quality in the swine '
holding area and dries the manure in the storage area (Figure 8-1). Clean air is pulled from the
ceiling through continuous baffle inlets and is directed down over the swine vertically (with no
horizontal, pig-to-pig air movement). Air exits the swine holding area through the floor slats and
is pulled horizontally to the outside of the first-floor pit area by 14 computer-controlled
Figure 8-1. High-Rise Hog Building
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ventilation fans mounted on the pit walls. This system prevents air from the manure pit from
rising to the animal area. The second part of the ventilation system involves pumping air through
the manure by floor aeration. PVC pipes with approximately 3,200 3/8-inch holes are installed
before the concrete floor is poured. Two large fans on either end of the building force air
through perforations in the concrete and into the composting mixture on the ground floor.
Application and Performance: Management practices, swine care, and feeding are much the
same as with conventional confinement. The High Rise facility is distinctive because it
incorporates dry manure handling and storage into a traditional confinement production scenario.
The system dries the manure mixture and maintains an aerobic environment to facilitate the
composting process. Drying and homogeneity of the mixture are also facilitated by mixing with
a tractor and loader or skid-steer loader. Frequency of mixing varies from once per production
cycle to biweekly, depending on the saturation of bedding. The semicomposted bedding mixture
is removed once per year and can be further composted, land applied, or sold. A typical 1,000-
head unit produces 500 tons of semicomposted product per year.
The High Rise facility is best suited for areas where there is limited local land base for manure
application; sandy, porous soils; limited water supply; or an existing.market for compost or
partially composted material.
The aerobic decomposition that occurs within the pit results in a significant volume reduction in
the manure. In fact, initial trials have shown that loading the pit with 12 to 18 inches
(approximately ll.tons) of bedding results in only 2.5 to 3 feet of manure to be removed at the
end of 1 year. This is estimated as a 22 percent reduction hi manure volume and a 66 percent
reduction in manure tonnage (Envirologic, 1999; Mescher, 1999). These figures are based on a
final product with 63 percent moisture. When compared with liquid/slurry hog manure that is
approximately 90 percent moisture, this presents a great advantage in areas where there is a lack
of local land base and manure must be transported more than 3 to 4 miles to alternative areas for
application. Manure with 63 percent moisture is considered to be in dry form and can be hauled
in a semi truck with an open trailer rather than hi a liquid tanker pulled by a tractor.
The aerobic decomposition and drying that reduce the volume and tonnage of the final organic
product do not result in a reduction of the overall nutrient content. In fact, with the exception of
N and sulfur (some of which volatilizes) nutrients will be more concentrated in the resulting
semicomposted product The semicomposted manure is four times more concentrated than liquid
manure from treatment lagoons. .
The High-Rise facility incorporates both manure treatment and storage in a completely
aboveground handling system. Li addition, the ground-level manure storage area is enclosed in
poured concrete. This is especially advantageous in sites with porous soils or fragmented
bedrock. Such locations are unfit or, at the least, potentially dangerous areas for earthen basin
and lagoon construction due to concerns regarding ground water contamination. Furthermore,
belowground concrete pits have an increased potential for ground water pollution if leaking .
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occurs in a region with porous soils or fragmented bedrock. The aboveground concrete manure
storage of the High-Rise building allows visual monitoring for leakage.
Information is not currently available on the reduction of pathogens, heavy metals, growth
hormones, or antibiotics in the manure product as it is removed from the High-Rise facility.
However, research on some of these topics is currently underway. Based on the composition of
the product, temperature readings within the manure pack, and knowledge of the composting
process, several speculations can be made. Destruction of pathogens in the composting process
is a result of time and temperature. The higher the temperature within the manure pack, the less
time it takes to eliminate pathogens. In general, the temperature within the manure pack needs to
exceed the body temperature of the animal and pathogen destruction is most effective at 120 °F
or higher. Temperature readings taken hi the manure pack in the High-Rise facility ranged from
only 45 to 78 °F (Keener, 1999). The predominant reason for the manure packs not reaching a
high enough temperature is the continuous aeration provided. It is unlikely that there is a
significant reduction of pathogens at this temperature. There may be some decrease in pathogen
numbers due to the length of time (up to one year) the manure pack remains in the building.
Further composting of the manure pack once it is removed from the High-Rise structure would
allow the product to reach temperatures high enough for complete pathogen destruction.
The composting process has no effect on the quantity of heavy metals in the manure. Further,
because of the decrease in volume and tonnage of the manure, heavy metals will be more
concentrated. Composting does, however, influence the bioavailability of the metals, causing
them to be less mobile. The extent to which the mobility of heavy metals is decreased in the
semicomposted product removed from the High-Rise facility is unknown.
The degree to which growth hormones and antibiotics degrade during the composting process is
unknown and is not widely studied.
Designers of the High-Rise facility claim a savings of 1.8 million gallons of water per 1,000 head
of hogs annually when compared with a conventional pull-plug flush unit. This conservation
results from using wet-dry feeders and eliminating the addition of water for manure removal and
handling. A reduction in the amount of water used in the system results in less waste product to
be handled.
Advantages and Limitations: As explained above, the dry manure handling system used in the
High-Rise facility significantly decreases the volume and tonnage of the final organic product.
This is an important advantage when transportation to areas where there is an increased land base
for manure application is necessary. However, because the semicomposted product has greater
concentrations of macronutrients, with the possible exception of N (which might volatilize), the
number of acres needed to correctly apply the manure does not decrease. Nitrogen volatilization
during the composting process creates the possibility of upsetting the nutrient balance in manure.
For example, if manure was applied to land with the application rate based on the amount of N in
the manure, P and potassium could be applied at rates 10 times the recommended rate. This
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problem is eliminated if application rates are based on the P content of manure. Additional
commercial N application might be necessary depending on the crop being produced.
Data from an initial trial show that the manure product removed from the High-Rise facility has a
fertilizer value of about $19 per ton at 60.7 percent moisture, with an organic matter content of
29.8 percent. Secondary studies show that the manure mixture is of adequate content for further
composting, which is necessary to sell manure commercially. These factors create an increased.
opportunity to broker manure and possibly provide supplemental income to the swine production
enterprise (Envirologic, 2000).
Observations and data resulting from the first year of study in the High-Rise structure indicate
that there is a significant decrease in odor using the dry manure handling system. Ammonia
measurements on the swine housing level averaged from 0 to 8 parts per million (ppm), with an
overall mean of 4.3 ppm and spikes of up to 12 ppm in times of decreased ventilation (winter
months). In a conventional confinement building with a deep, liquid pit, ammonia levels of 20
to 30 ppm are commonplace. Ammonia levels on the ground level of the High-Rise building
vary inversely with building ventilation and have exceeded a short-term exposure rate of 50 ppm
in the winter. It must be realized, however, that the basement level is not occupied during
normal conditions. Large sliding doors are opened when the facility is cleaned to let in fresh air
and facilitate the entry of a tractor/loader. Ammonia levels external to the outside exhaust fans
averaged 23.3 ppm, but quickly dissipated (Keener et al., 1999).
No hydrogen sulfide gas was detected in the swine holding area. Levels on the first floor ware
minimal (National Hog Farmer, 2000). Decreased levels of these potentially toxic gases improve
air quality and prevent excessive corrosion in the building.
Producers who plan to build a High-Rise facility can expect a 15 percent increase hi capital
outlay compared to a 1,000-head, tunnel ventilation finisher with an 8-foot-deep pit. Cost
projections prepared for the company that manufactures the High-Rise building indicate that
reduced cost for manure handling and transportation offsets the additional building cost
(Envirologic, 2000). Solid manure handling is less automated than many liquid manure handling
systems. Although solid systems have lower capital costs, labor costs are higher than those
associated with liquid systems. Labor costs are expected to be less than traditional scrape and
haul systems because the slatted floors eliminate the need to scrape animal areas frequently.
In addition to the increased capital requirement, the cost of utilities is also elevated. Additional
energy is needed to power the many ventilation fans. Electricity usage averages roughly twice
that of a naturally ventilated confinement bam. Accounting for all of these factors, the cost of
production in a High-Rise facility is approximately $180 per pig. This is 28 to 30 percent greater
than the cost of production in a confinement structure with a shallow pit, and 15 to 18 percent
greater than in a more conventional deep pit (Mescher et al., 1999).
The ventilation system that pumps air over the swine holding area keeps the swine and slats 'dry,
resulting in cleaner swine and fewer injuries. Also, there is no flow of air from pig to.pig, which
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helps prevent airborne transmission of disease. The combination of decreased moisture and
exceptional ah" quality leads to unproved animal health and decreased medication costs.
Data from a single High-Rise facility show that animal performance was the same or better than
that of conventional facilities with respect to average daily gain, days to market, feed conversion,
mortality, and the number of culls. In fact, the decreased number of days to market translates
into 0.2 to 0.3 more production cycles per year, creating potential to increase profits significantly.
It is speculated that improvement in performance measures is due to better air quality
(Envirologic, 2000).
Leachate from the manure mixture appears to be minimal if mixing is done on a regular basis.
Rodents hi the basement pit might become a problem if control measures are not taken.
tf
Operational Factors: Artificial climate control and ventilation in the building make the High-
Rise building appropriate in most climates . It is estimated that air in the building is exchanged
every 10 to 15 seconds, providing an environment of uniform temperature and humidity
throughout the building year-round. Over a 1-year span, the mean air temperature taken from
several test areas within the building varied only ± 2 °F from the desired temperature. There
were, however, differences of up to 10 °F between testing areas on the swine floor (Stowell et
al., 1999). The building is equipped with a standard sprinkling system for use in hot summer
months.
Demonstration Status: The High-Rise facility technology has been tested with finisher pigs since
1998 at a single research facility in Darke County, Ohio. The vendor has built four commercial
grow-finish buildings since that time and they are currently in production in west central Ohio.
The vendor is also developing prototypes for other phases of swine production using the same
manure handling system.
Practice: Hoop Structures
Description: Hoop structures are low-cost, Quonset-shaped swine shelters with no form of
artificial climate control. Wooden or concrete sidewalk 4 to 6 feet tall are covered with an
ultraviolet and moisture-resistant, polyethylene fabric tarp supported by 12- to 16-gauge tubular
steel hoops or steel truss arches placed 4 to 6 feet apart. Hoop structures with a diameter greater
than 35 feet generally have trusses rather than the tubing used on narrower hoops. Some
companies market hoops as wide as 75 feet. Tarps are affixed to the hoops using ropes or
winches and nylon straps.
Generally, the majority of the floor area is earthen, with approximately one-third of the south end
of the building concreted and used as a feeding area. The feeding area is designed with a slight
slope (1 to 2 percent) to the outside of the building in case of a waterline break and is raised 12 to
19 inches above the earthen floor to keep the feeding area clear of bedding material.
Approximately 150 to 200 finisher hogs or up to 60 head of sows are grouped together in one
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large, deep-bedded pen. The building should be designed so that the group housing area
provides approximately 12 square feet of space per finisher pig, or 27 square feet per sow.
Hoop structures are considered a new and viable alternative for housing gestational sows and
grow-finish pigs. Gestational housing systems being used in the United States are modeled after
conventional Swedish style, deep-bedded gestation and breeding housing. In Sweden today,
deep-bedded housing systems with individual feeding stalls are the conventional method of dry
sow housing. There are feeding stalls for each sow, with connecting rear gates and individually
opening front gates, a deep-bedded area for the group-housed sows, and bedded boar pens. The
stalls are raised approximately 16 inches above the ground to accommodate the deep-bedding
pack in the center.
la each production scenario, plentiful amounts of high quality bedding are applied to the earthen
portion of the structure, creating a bed approximately 12 to 18 inches deep. The heavy bedding.
absorbs, animal manure to produce a solid waste product. Additional bedding is added
continuously throughout the production cycle. Fresh bedding keeps the bed surface clean and
free of pathogens and sustains aerobic decomposition. Aerobic decomposition within the bedding
pack generates heat and elevates the effective temperature in the unheated hoop structure,
improving animal comfort in winter conditions.
Application and Performance: The hoop structure originated in the prairie provinces of Canada.
Recently, interest in this type of structure has increased in Iowa and other states hi the Midwest.
Swine production in this type of facility is most prevalent for finishing operations, but is also
used to house dry gestational sows. Other possible uses in swine production include gilt
development, isolation facilities, housing for light pigs, breeding barns, farrowing, and
segregated, early weaning swine development. A hoop structure is an appropriate alternative for
moderately sized operations. An "all in, all out" production strategy must be used with finishing
pigs.
The manure from hoop structures is removed as a solid with the bedding pack. The high volume
of bedding used creates an increased volume of waste to be removed. Typically, a front-wheel
assist tractor with a grapple fork attachment on the front-end loader is required to clean out the
bedding pack. In a finishing production system, the bedding pack is removed at market time,
usually two to three times per year. In gestational sow housing, slightly less bedding is required,
and the bedding pack is typically removed one to four times a year depending on the stocking
density and quality of bedding.
A limited amount of information is available on the manure characteristics, both inside the hoop
and during consequent manure management activities. The manure content within the pack is
highly variable. Dunging areas are quickly established when swine are introduced into the deep-
bedded structure. These areas contain a majority of the nutrients within the pack. Results of an
Iowa State University study are shown in Table 8-4. Samples were taken on a grid system at nine
areas throughout the bedding pack (three samples along the west side of the building, three along
the center, three along the east).
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Table 8-4. Examples of Bedding Nutrients Concentrations
Site
Westl
West2
Wests
Centerl
Center2
Centers
Eastl
Bast2
Easts
Mean
Standard Deviation
Bedding Nutrients by Location3
Total Moisture
(percent)
73.7
75.2
68.5
67.4
22.9
27.6
68.5
30.6
73.5
56.4
223
Total Nitrogen
Ob/ton)
20
22
22
14
11
22
29
36
16
21.3
76
Phosphorus
(Ib/ton)
2-1
22
31
20
21
17
24
40
13
23.2
7 6
Potassium
Ob/ton)
12
12
. 16
26
37
26
29
51
15
24.8
11 A
Adapted irorn Kicnara et al.,
Temperatures throughout the bedding pack also varied greatly. Bedding temperature was highest
in the sleeping/resting area where the moisture content is approximately 50 percent. Bedding
temperatures werelowest in the wet dunging areas that contain 60 to 70 percent moisture. The
lower temperatures were likely caused by anaerobic conditions that prevent oxidation of carbon
and, therefore, reduce the amount of heat generated (Richard et al., 1997; and Richard and Smits
1998). '
Richard et al. and Richard and Smits (1997,1998) also examined the loss of N in the hoop
structure bedding pack. One-third of the N was lost while swine were housed in the structure.
This loss was hypothesized to be caused largely by ammonia volatilization and possibly from
nitrate leaching. An additional 10 percent reduction in N occurred as the bedding pack was
removed from the hoop. This loss was also hypothesized as being a result of ammonia
volatilization. Additional N was lost during the composting process, with the amount lost
corresponding to the specific composting process demonstrated. In general, the composting
process that resulted hi the greatest reduction of volume also had the greatest N loss (Richard and
Smits, 1998).
Nitrogen leaching potential was examined in yet another study, at Iowa State University. The
hoop facility used hi this trial was located on hard-packed soil with a high clay-content.
Following one production cycle, the surface NO3-N was 5.5 times greater than the initial level.
There was no significant change in NO3-N at other depths ranging to 5 feet. Following a second
production cycle, the NO3-N levels at all depths to 5 feet increased three times compared with
those taken following the initial production cycle (Richard et al., 1997). Nitrate was the only
form of N tested.
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The Medina Research Centre in Australia studied N and P accumulation in the soil beneath hoop
structures. The hoop structures were constructed on Swan Coastal Plain sandy soils. Two trials
were conducted in the same location approximately 6 weeks apart. In each trial there was no
increase in the concentration of extractable P in the soil profile when compared with baseline
data (Jeffery, 1996).
Advantages and Limitations: The quality of the work environment in a deep-bedded hoop
structure is generally good. There is no liquid manure and therefore less odor than with
conventional systems. The building structure and recommended orientation provide for a large
volume of naturally ventilated air. Also, because the manure is solid, storage requirements are
minimized.
The high degree of variability within the bedding pack makes it difficult to predict nutrient
content Some areas can have a high fertilizer value, whereas others have high carbon and low
N content The latter can lead to N immobilization and result in crop stress if applied during or
immediately prior to the growing season. For these reasons, it is desirable to mix the bedding
pack to achieve a higher degree of uniformity. Some mixing will occur during the removal and
storage of the manure. Treatments that allow for additional mixing, such as composting in
windrows, appear to offer considerable benefits. Initial studies at Iowa State University found
that composting unproved uniformity, and provided for a 14 to 23 percent reduction in moisture
and a 24 to 45 percent reduction in volume (Richard and Smits, 1998). It should be noted that
bedding from gestational sow facilities is typically drier than that from finishing facilities. The
lack of moisture is likely to limit the extent of composting unless additional manure or moisture
is added.
Trials comparing a conventional confinement system to hoop structures have been performed at
Iowa State University. The swine raised in the hoop structure experienced similar performance.
Specifically, there was a low level of swine mortality (2.6 to 2.7 percent), comparable and
acceptable average daily gain, and a slightly poorer feed efficiency (8 to 10 percent) for swine
raised in the whiter months (Honeyman et al, 1999). Poor feed efficiency in whiter months is
due to an increased nutrient/energy requirement to maintain body heat. These findings supported
an earlier study by the University of Manitoba that found swine finished hi hoop structures to
have excellent health, similar rates of gain, poorer feed efficiency in colder months (10 to 20
percent), low swine mortality, and similar days to market (Conner, 1993). Moreover, similar
results were found hi a South Dakota State University study. Several researchers have identified
proper nutrition for swine raised hi hoops as an area needing further research.
With respect to housing dry gestational sows, providing a lockable feeding area for each sow
affords similar advantages to those of traditional gestation crates. Producers have the ability to
keep feed intake even, eliminate competition for feed, administer treatments and medication
effectively, lock sows hi for cleaning and bedding, and sort and transfer sows for breeding or
farrowing through the front gates. Furthermore, group housing stimulates estrus (the period of
time within a female's reproductive cycle in which she will stand to be bred), reduces stress to -
the sow, and alleviates many foot and leg problems common hi sows. Fighting is minimized by
• 8-32
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the use of feeding stalls and introducing new sows at optimal times, such as farrowing.
Concreting the deep-bedded section to prevent sows from rooting is an option, but it increases
capital outlay (Honeyman et al., 1997).
Iowa State University has conducted demonstration trials on gestating sows in deep-bedded hoop
structures. Conception rate, farrowing rate, number of swine born alive, and birth weight on
groups gestated in the hoop structure were all excellent. The sow performance results indicate
that hoop structures are an exceptional environment for gestating sows. It must be noted,
however, that sow groups were not mixed and new sows were not introduced during the trial.
With respect to breeding, hot weather is of greater concern than cold weather. Excessive high
temperatures can be detrimental to breeding performance. Boars exposed to elevated effective
temperatures will experience poor semen quality for a 6- to 8-week period that begins 2 to 3
weeks following exposure. Sows are more tolerant to high temperatures, except during the first 2
to 3 weeks of gestation and the final 2 weeks prior to farrowing. Litter size and birth weight can
be severely altered during these periods (Honeyman et al., 1997).
Iowa State University has also conducted preliminary trials with farrow-to-finish production,
early weaned pigs, and wean-to-finish production. These studies concluded that, although each
may be a viable alternative, many details must still be worked out before they all become
successful consistently.
The hoop system offers several benefits with respect to animal welfare and behavior. Honeyman
et al. (1997) stated that one of the most extreme stresses in livestock production results when an
animal is prevented from controlling various aspects of its environment. This lack of control is
apparent in many of today's conventional production systems and is responsible for an unduly
high level of stress that affects general health, reproduction, arid welfare. Production in a deep-
bedded hoop structure allows each animal to control its own microenvironment by burrowing
down into the bedding, huddling, or lying on top. Deep-bedded hoops also allow swine to root
through and ingest some bedding at will. This is especially advantageous in dry-sow gestational
housing. The behavior serves two purposes. First, swine have an inherent drive to root. Being
able to do so prevents frustration, boredom, and, hence, aggression. Second, consumption of
bedding material quiets any hunger the pig may feel. Increased genetic evolution has led swine
to have an increased drive to eat. Gestating sows are typically fed a limited amount of feed,
satisfying what is estimated to be only 30 to 50 percent of their appetite. Stereotypic behavior is
indicative of a suboptimal environment and will ultimately have implications on an animal's
general health and production. No evidence of Stereotypic behavior is cited in any of the deep-
bedded system studies (Honeyman etal., 1997).
The initial capital outlay for hoop structures is about 30 percent less than the capital requirement
associated with a typical double-curtain swine finishing building (Harmon and Honeyman,
1997). Additionally, hoop structures are highly versatile and have many alternative uses (e.g.,
equipment storage) if production capacity is not needed. Production in hoop structures requires a
greater amount of feed and large volumes of high quality bedding, however. Bedding is the key
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to successful production in hoop structures. These differences make the cost of production
comparable to that of a traditional confinement setting.
Hoop structures are easy to construct with on-farm labor. In Iowa State University trials, hoop
structures show no visible signs of deterioration after 4 years (Honeyman, 1995). The average
useful life of a hoop structure is estimated to be 10 years (Brumm, 1997)!
The amount of bedding used in the studies averages 200 pounds per finisher pig in each
production cycle, with a greater amount of bedding being used in the whiter months. It is
estimated that approximately 1,800 pounds of high quality bedding per gestational sow are
needed each year (Halverson, 1998). The amount of labor is directly proportional to the amount
of bedding and ranges from 0.3 to 0.6 hours per pig (Richard et al., 1997). A survey distributed
to producers of finishing pigs in hoop structures and compiled by Iowa State University found
actual labor requirements to average 0.25 hours per pig (Duffy and Honeyman, 1999). Labor
requirements rely on many factors, including farm size, level of automation, and experience with
the production system. Based on the trials conducted at each university, the labor requirement
was considered to be reasonable and competitive with other finishing systems (Conner, 1993;
Richard etal., 1997).
The large amount of bedding required in hoop structure production can limit its feasibility for
some producers. Many types of bedding can be used. Corn stalks, oat straw, wheat straw, bean
stalks, wood shavings, and shredded paper have all been used with some success, although
shredded corn stalks are the most common. Selection of the appropriate bedding type is based on
many factors. First, the availability of bedding must be considered. This is specific to
geographical area but may also be limited by climate. An early snow or a wet fall could prevent
stalk baling. Second, in several areas of the Midwest, federally mandated conservation plans on
highly erodible land require residue to be left on the land. In such cases, harvesting corn and
bean stalks may not be appropriate. Finally, bedding storage is an important consideration.
Generally, bedding baled in the fall and used by the spring can be stored outdoors. Bedding
needed for spring and summer use, however must be stored undercover in a well-drained area to
avoid loss in quality and quantity.
Internal parasite control must be aggressive because swine are continually in contact with their
feces. Several of the Iowa State University studies note that flies are a potential problem for
hoop houses in warm months. Furthermore, rodent and bird problems may be difficult to control.
Also, in the summer, incidental composting within the bedding pack can create unwelcome heat
and may lessen the animals' comfort. It has not been determined whether there is severe
potential for disease and parasite buildup in the soil beneath the hoop structure.
Operational Factors: Production in a hoop structure relies on bedding, intensive management,
and keen husbandry for success. Climate control is a major factor in determining the feasibility of
deep-bedded hoop structures.- The recommended orientation of the buildings is north to south
(depending on geographical area), to take advantage of the prevailing summer winds. Air enters
the facility through spaces between the sidewall and the tarp and at the ends. Warm, moist air
8-34
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moves toward the top of the arch and is earned out the north end by natural currents. Various
end structures are available that supply adjustable levels of ventilation. In the winter months the
north end is generally closed and the south is at least partially opened. If the ends are closed too
tightly, high levels of humidity can become a problem. On average, the inside air temperature in
the winter is only 5 ° to 8 ° F warmer than outside temperatures. This is different from the
effective temperature which the swine can alter by burrowing into the deep bedding. In summer
months, both ends are left open. Ultraviolet resistant tarp and sprinklers inside the structure help
to control the temperature within the structure. Air temperature in the summer averages 2° to 4°
F lower than outside temperature (Harmon and Xin, 1997). The length of the hoop structure also
has an effect on air temperature because of the rate of air exchange. Wider and longer hoop
structures often have ridge vents to improve ventilation.
Demonstration Status: Hoop structures have been used successfully in the United States for
housing finishing pigs and dry gestational sows. Grow-finish production is the most common
use for hoop structures in swine production. Recently, there has been an increased interest in this
type of production system in the Midwest, including the states of Iowa, Illinois, Minnesota,
Nebraska, and South Dakota. It is estimated that more than 1,500 hoop structures have been
built for swine production in Iowa since 1996 (Honeyman, 1999). Furthermore, initial
demonstrations have been conducted with early weaned pigs and in farrow-to-finish production.
Hoop structures are being used to house swine in at least seven Canadian provinces. Currently,
more than 400 hoop structures are used for swine finishing in Manitoba (Conner, 1994).
Practice; Rotational Grazing
Description: Intensive rotational grazing is known by many terms, including intensive grazing
management, short duration grazing, savory grazing, controlled grazing management, and voisin
grazing management (Murphy, 1998). This practice involves rotating grazing cattle (both beef
and dairy) among several pasture subunits or paddocks to obtain maximum efficiency of the
pasture land. Dairy cows managed under this system spend all of their time not associated with
milking out on the paddocks during the grazing season and beef cattle spend all of their time out
on the paddocks during the grazing season. Intensive rotational grazing is rarely if ever used at
swine and poultry operations. Nonruminants such as swine and poultry are typically raised in
confinement because of the large number of animals produced and the need for supplemental
feed when they are raised on pastures. .
Application and Performance: Rotational grazing is applicable to all beef and dairy operations
that have sufficient land. During intensive rotational grazing, each paddock is grazed quickly (1
or 2 days) and then allowed to regrow, ungrazed, until ready for another grazing. The recovery
period depends on the forage type, the forage growth rate, and the climate, and may vary from 10
to 60 days (USDA, 1997). This practice is labor- and land-intensive as cows must be moved
daily to new paddocks. All paddocks used in this system require fencing and a sufficient water
supply. Many operations using intensive rotational grazing move their fencing from one paddock
to another and have a water system (i.e., pump and tank) installed in each predefined paddock
area.
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The number of required paddocks is determined by the grazing and recovery periods for the
forage. For example, if a pasture-type paddock is grazed for 1 day and recovers for 21 days, 22
paddocks are needed (USDA, 1997). The total amount of land required depends on a number of
factors including the dry matter content of the pasture forage, use of supplemental feed, and the
number of head requiring grazing., Generally, this averages out to one or two head per acre of
pasture land for both beef and dairy cattle (Hannawale, 2000). Successful intensive rotational
grazing, however, requires thorough planning and constant monitoring. All paddocks should be
monitored once a week. High-producing milk cows (those producing over 80 Ibs/day) need a
large forage allowance to maintain a high level of intake. Therefore, they need to graze in
pastures that have sufficient available forage or be fed stored feed (USDA, 1997). It is also
expected that beef cattle would need sufficient forage or stored feed to achieve expected weight
gains.
The climate in many regions is not suitable for year round rotational grazing. Operations hi these
regions must maintain barns and/or dry lots for the cows when they are not being grazed or
outwinter their cows. Outwintering is the practice of managing cows outside during the winter
months. This is not a common practice because farmers must provide additional feed as cows
expend more energy outside hi the whiter, provide windbreaks for cattle, conduct more frequent
and diligent health checks on the cows, and keep the cows clean and dry so that they can stay
warm (CIAS, 2000).
There are two basic management approaches to outwintering: rotation through paddocks and
sacrifice paddocks. Some farms use a combination of these practices to manage their cows
during the whiter. During whiter months, farmers may rotate cattle, hay, and round bale feeders
throughout the paddocks. The main differences between this approach and standard rotational
grazing practices are that the cows are not rotated as often and supplemental feed is provided, to
the animals- Deep snow, however, can cause problems for farmers rotating their animals hi the
whiter because it limits the mobility of round bale feeders. The outwintering practice of
"sacrifice paddocks" consists of managing animals hi one pasture during the entire whiter. There
are several disadvantages and advantages associated with this practice. If the paddock surface is
not frozen during the entire whiter, compaction, plugging (tearing up of the soil), and puddling
can occur. Due to the large amounts of manure deposited hi these paddocks during the whiter,
the sacrificial paddocks must be renovated hi the spring. This spring renovation may consist: of
dragging or scraping the paddocks to remove excess manure and then seeding to reestablish a
vegetative cover. Some farmers place sacrifice paddocks strategically in areas where an
undesirable plant grows or where they plan to reseed the pasture or cultivate for a crop (CIAS,
2000).
EPA conducted an analysis to estimate the manure reduction achievable with intensive rotational
grazing at model beef and dairy operations (ERG, 2000a). Outwintering was not assumed to
occur in this analysis. During the months that the cows from the model dairies and feedlots were
assumed not to be on pasture,- the amount of manure that must be managed is assumed to be
equal to the amount produced at equal size confined dairy operations and beef feedlots. Table 8-
5 presents the estimated range of months that intensive rotational grazing systems might be used
8-36
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at dairy farms and beef feedlots located in each of the five geographical regions included in this
analysis. .
Table 8-5. Amount of Time That Grazing Systems May Be Used at
Dairy Farms and Beef Feedlots, by Geographic Region
Region
Pacific
Central
Midwest
Mid-Atlantic
South .
Annual Use of Grazing Systems (months)
3-12
3-12
3-6
3-9
9-12
It is estimated that approximately 15 percent of the manure generated by dairy cows is excreted
in the milking center and 85 percent is excreted in the housing areas (i.e., bams, dry lots,
pastures) (USDA NRCS, 1996). It is also estimated that 23 percent to 28 percent of the
wastewater volume generated from a flushing dairy operation comes from the milking center and
72 percent to 77 percent (median of 75 percent) of the wastewater comes from flushing the bams
(USEPA, 2000). All wastewater from a hose-and-scrape dairy system is generated at the milking
center. Thus, dairies using intensive rotational grazing systems would manage 85 percent less
solid manure and'approximately 75 percent less wastewater (for flushing operations) than
confined systems, during the months that the cows are on pasture.
All of the manure generated at beef feedlots using intensive rotational grazing systems would be
excreted on the pasture during the months that the cows are grazing. No significant amounts of
process wastewater are generated at beef feedlots. Thus, beef feedlots using intensive rotational
grazing systems would manage 100 percent less solid waste during the months that the cows are
on pasture.
Two model farm sizes were analyzed for dairy farms, assuming an average size of 454 (for
medium-sized dairies) and 1,419 milking cows (for large-sized dairies). Both of these size
groups are significantly larger than the 100 head or smaller operations expected to use intensive
rotational grazing systems. Therefore, the specific model farm calculations are viewed as
significantly overestimating the amount of collected manure and wastewater that could be
reduced at typical intensive rotational grazing operations versus confined operations. For this
reason, estimates on collected manure and wastewater reduction are presented on a per-head
basis and model farm basis for the two dairy farm types (flushing, hose and scrape) included in
EPA's Effluent Limitations Guidelines (ELG) analysis for each of the five geographical regions.
Three model farm sizes were analyzed for beef feedlots, assuming an average size of 844 (for
medium-sized feedlots), 2,628 (for large-sized feedlots), and 43,805 beef slaughter steer (for very
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large feedlots). Due to the slow weight gain associated with grazing operations for beef cattle
and required number of pasture acres, beef feedlots of these sizes are not expected to use
intensive rotational grazing systems. However, estimates on collected manure reductions are
presented on a per-head basis and model farm basis for the three sizes of beef feedlots included
in EPA's ELG analysis for each of the five geographical regions.
Table 8-6 presents the expected reduction in collected manure and wastewater for flush and hose-
and-scrape dairy operations, by head, and by region. Table 8-7 presents the expected reduction in
collected manure and wastewater for dairy operations by model farm, and by region. Table 8-8
presents the expected reduction in collected manure for beef feedlots, by head, and by region.
Table 8-9 presents the expected reduction in collected manure for beef feedlots by model farm,
and by region.
Table 8-6. Expected Reduction in Collected Solid Manure and Wastewater at Dairies
Using Intensive Rotational Grazing, per Head
Farm Type
Flush
Hose and Scrape
Region
Pacific
Central
Midwest
Mid-Atlantic
South
Pacific
Central
Midwest
Mid-Atlantic
South
Manure Reduction
(Ib/yr/head)
10,200-41,500
10,200-41,500
10,200-20,500
10,200-30,700
30,700-41,500
10,200-41,500
10,200-41,500
10,200-20,500
10,200-30,700
30,700-41,500
Wastewater Reduction
(gal/yr/head)
9,000-36,500
9,000 - 36,500
9,000-18,000
9,000-27,000
27,000-36,500
0
0
0
0
0
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Table 8-7. Expected Reduction in Collected Solid Manure and Wastewater at Dairies
Using Intensive Rotational Grazing, per Model Farm
Farm
Size
(head)
454
454
1,419
1,419
Farm
Type
Flush
Hose&
Scrape
Flush
Hose
and
Scrape .
Region
Pacific
Central
Midwest
Mid-Atlantic
South
Pacific
Central
Midwest
Mid-Atlantic
South
Pacific
Central
Midwest
Mid-Atlantic
South
Pacific
Central
Midwest
Mid-Atlantic
South
Manure Reduction
Qb/yr/farm)
4,630,800 - 18,841,000
4,630,800 - 18,841,000
4,630,800-9,307,000
4,630,800-13,937,800
13,937,800-18,841,000
4,630,800 - 18,841,000
4,630,800 - 18,841,000
4,630,800-9,307,000
4,630,800-13,937,800
• 13,937,800-18,841,000
14,473,800-58,888,500
14,473,800-58,888,500
14,473,800-29,089,500
14,473,800-43,563,300
43,563,300-58,888,500
14,473,800 - 58,888,500
14,473,800 - 58,888,500
14,473,800 - 29,089,500
14,473,800-43,563,300
43,563,300-58,888,500
Wastewater Reduction
(gal/yr/farm)
4,086,000 - 16,571,000
4,086,000 - 16,571,000
4,086,000-8,172,000
4,086,000-12,258,000
12,258,000-16,571,000
0
0
0
0
0
12,771,000-51,793,500
12,771,000-51,793,500
12,771,000-25,542,000
12,771,000-38,313,000
38,313,000-51,793,500
0
0
0
0
0
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Table 8-8. Expected Reduction in Collected Solid Manure at
Beef Feedlots Using Intensive Rotational Grazing, per Head
Region
Pacific
Central
Midwest
Mid-Atlantic
South
Manure Reduction
(ib/yr/head)
5,040-20,167
5,040-20,167
5,040-10,080
5,040 - 15,120
15,120-20,167
Table 8-9. Expected Reduction in Collected Solid Manure at
Beef Feedlots Using Intensive Rotational Grazing, per Model Farm
Farm Size (head)
844
2,628
43,805 ,
Region
Pacific
Central
Midwest
Mid-Atlantic
South
Pacific
Central
Midwest
Mid-Atlantic
South
Pacific
Central
Midwest
Mid-Atlantic
South
Manure Reduction
(Ib/yr/farm)
4,255,170-17,020,680
4,255,170-17,020,680
4,255,170-8,510,340
4,255,170 -.12,765,510
12,765,510-17,020,680
13,249,500-52,998,000
13,249,500-52,998,000
13,249,500-26,499,000 .
13,249,500-39,748,500
39,748,500-52,998,000
220,849,640-883,398,550
220,849,640 - 883,398,550
220,849,640 - 441,699,280
220,849,640-662,548,910
662,548,910-883,398,550
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Advantages and Limitations: Compared with traditional grazing, intensive rotational grazing has
been identified as environmentally friendly and, when managed correctly, is often considered
better than conventional or continuous grazing. The benefits associated with intensive rotational
grazing versus conventional grazing include:
* Higher live-weight gain per acre. Intensive rotational grazing systems result in high
stocking density, which increases competition for feed between animals, forcing them to
spend more time eating and less time wandering (AAC, 2000).
• Higher net economic return. Dairy farmers using pasture as a feed source will produce
more feed value with intensive rotational grazing than with continuous grazing (CIAS,
2000). Competition also forces animals to be less selective when grazing. They will eat
species of plants that they would ignore in other grazing systems. This reduces less
desirable plant species in the pasture and produces a better economic return (AAC, 2000).
• Better land. Pasture land used in rotational grazing is often better maintained than typical
pasture land. Intensive rotational grazing encourages grass growth and development of
healthy sod, which in turn reduces erosion. Intensive rotational grazing in shoreline areas
may help stabilize stream banks and could be used to maintain and improve riparian
habitats (PPRC, 1996).
• Less manure handling. In continuous grazing systems, pastures require frequent
maintenance to break up large clumps of manure. In a good rotational system, however,
manure is more evenly distributed and will break up and disappear faster. Rotational
grazing systems may still require manure maintenance near watering areas and paths to
and from the paddock areas (Emmicx, 2000).
Grazing systems are not directly comparable with confined feeding operations, as one system can
not readily switch to the other. However, assuming all things are equal, intensive rotational
grazing systems might have some advantages over confined feeding operations:
• Reduced cost. Pasture stocking systems are typically less expensive to invest in than
livestock facilities and farm equipment required to harvest crops. Feeding costs may also
be lowered.
• Improved cow health. Dairy farmers practicing intensive rotational grazing typically have
a lower cull rate than confined dairy farmers, because the cows have less hoof damage,
and they are more closely observed by the farmer as they are moved from one paddock to
another (USDA, 1997).
• Less manure handling. Intensive rotational grazing operations have less recoverable solid
manure to manage than confined operations.
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• Better rate of return. Research indicates that grazing systems are more economically
flexible than the confinement systems. For example, farmers investing in a well-planned
grazing operation will likely be able to recover most of their investment in assets if they
leave farming in a few years. But farmers investing from scratch in a confinement
operation would at best recover half then* investments if they decide to leave farming
(CIAS, 2000).
The disadvantages associated with intensive rotational grazing compared with either
conventional grazing or confined dairy operations include:
• Limited applicability. Implementation of intensive rotational grazing systems is
dependent upon available acreage, herd size, land resources (i.e., tillable versus steep or
rocky), water availability, proximity of pasture area to milking center (for dairy
operations), and feed storage capabilities. Typical confined dairy systems and beef
feedlots are often not designed to allow cows easy access to the available cropland or
pastureland. Large distances between the milking center and pastureland will increase the
dairy cow's expended energy and, therefore, increase forage demands.
In most of the country, limited growing seasons prevent many operations from
implementing a year-round intensive rotational grazing system. Southern states such as
Florida can place cows on pasture 12 months of the year, but the extreme heat presents
other problems for cows exposed to the elements. Grazing operations in southern states
typically install shade structures and increase water availability to cows, which in turn
increases the costs and labor associated with intensive rotational grazing systems.
Because most operations cannot provide year-round grazing, they still must maintain
bams and dry lot areas for their cows when they are not grazing, and operations often
prefer not to have to maintain two management systems.
* Reduced milk production levels. Studies indicate that dairy farmers using intensive
rotational grazing have a lower milk production average than confined dahy farms (CIAS,
2000). Lower milk production can offset the benefit of lower feed costs, especially if
rations are not properly balanced once pasture becomes the primary feed source during
warm months.
• Reduced weight gain. Beef cattle managed in an intensive rotational grazing system
would gain less weight per day than beef cattle managed on a feedlot unless they were
supplied with extensive supplemental feed.
• Increased likelihood of infectious diseases. Some infectious diseases are more likely to
occur in pastured animals due to direct or indirect transmission from wild animals or the
presence of an infective organism hi pasture soil or water (Hutchinson, 1998).
• Limited flexibility. Intensive rotational grazing systems have limited flexibility in
planning how many animals can be pastured in any one paddock. Available forage in a
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paddock can vary from one cycle to another, because of weather and other conditions that
affect forage growth rates. As a result, a paddock that was sized for a certain number of
cows under adequate rainfall conditions will not be able to accommodate the same
number of cows under drought conditions (USD A, 1997).
Operational Factors: As mentioned earlier, most dairy operations and beef feedlots cannot
maintain year-round intensive rotational grazing systems. These systems are typically operated
between 3 and 9 months of the year-with 12 months most likely in the southern states. Although
outwintering is a possibility for year round grazing in more northern states, it is not a common
practice.
Demonstration Status: Due to the labor, fencing, water, and land requirements of intensive
rotational grazing, typically only small dairy operations (those with less than 100 head) use this
practice (Hannawale, 2000; USDA NRCS, 2000; CIAS, 2000). Few beef feedlots practice
intensive rotational grazing. Climate and associated growing seasons make it very difficult for
operations to use an intensive rotational grazing system throughout the entire year.
Practice: Pasture-Based Systems at Swine Operations
Description: There are three main types of outdoor management systems at swine operations:
pasture, open lots, and buildings with outside access. In pasture systems, crops are grown and
the animals are allowed to forage for their own food. Open lots are generally nonvegetative areas
where the animals are allowed to roam. These open lots are typically available to animals that
are housed in buildings with outside access. The focus of this discussion is the pasture systems.
Application and Performance: This practice is applicable to any swine operation that has
sufficient land. However, the practicality of the practice decreases with operation size.
Wheaton and Rea (1999) found that the use of a good pasture containing such crops as alfalfa,
clover, and grasses can support about 8 to 10 sows. Stocking rates, however, will depend uppn
soil fertility, quality of pasture, and time of year. The recommended stocking rates are (Wheaton
and Rea, 1999): .
Sows with litters
Pigs from weaning to 100 pounds
Pigs from 100 pounds to market
Gestating sows
6 to 8 head per acre
15 to 30 head per acre
10 to 20 head per acre
8 to 12 head per acre
Wheaton and Rea (1999) also found that pastured swine must receive two to three pounds of
grain daily plus minerals and salt for proper weight gain. Adequate shade and water must also be
provided to pastured swine. Swine can be very tough on pastures and soil. Therefore, it is
recommended that producers rotate swine after each season and use the pasture for other animals
or harvest hay for about 2 years before using it again for swine (Wheaton and Rea, 1999). All the
waste produced by the animals while they are pastured is incorporated into the sod, and therefore
requires minimal waste disposal.
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Advantages and Limitations: A pasture-based system offers a number of advantages and
disadvantages over confinement housing to swine producers. The advantages include (Wheaton
andRea, 1999):
• Lower feed costs on good pasture;
• Exercise and nutrients for breeding sows;
• Lower capital investment per production unit;
• Good use of land not suitable for machine harvest;
• Better isolation and disease control;
• Decreased waste management handling; and
• Decreased cannibalism. ,
The disadvantages include (Wheaton and Rea, 1999):
• Increased labor for animal handling, feeding, and watering;
• Increased risk of internal parasites;
• Increase labor for farrowing;
• Increase animal production time to reach desired market weight; and
• Lack of environmental controls.
Operational Factors: The increased labor costs associated with pasture-based swine operations
are partially offset by decreased waste handling costs and reduced feed costs.
Demonstration Status: Data from the USDA's Animal and Plant Health Inspection Service -
Veterinary Service indicate pasture-based systems are used at 7.6 percent of farrowing
operations, 1.5 percent of nurseries, and 6.7 percent of finishing operations (USDA APHIS,
1995). The percentage of pigs raised on such operations is about five times less than the number
' of operations, indicating these operations are generally smaller than other types of swine
operations. NAHMS confirmed this with additional analysis of the Swine '95 data, and indicated
7 to 8 percent of swine farms with fewer than 750 total head use pasture systems, but less than 1
percent of swine operations larger than 750 head use pasture systems (USDA NAHMS, 1999).
Practice: Pasture-Based Systems at Poultry Operations
Description: Pastured poultry refers to broilers, layers, and turkeys that are raised on pasture and
feed. There are three basic methods for raising poultry on pasture: pasture pens, free range, and
day range (Lee, 2000). Pasture pens are bottomless pens that hold layers, broilers, or turkeys, and
are moved daily or as needed to give the poultry fresh pasture. This is the most commonly used
pasture poultry method at present. To accommodate layers, nest boxes, are fixed to the side of the
pen. Approximately 30 to 40 hens can be housed in one typical pasture pen. Free range
generally means a fenced pasture surrounding the barn or poultry shelter, and day range is similar
to free range except that the birds are sheltered at night from predators and weather.
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Application and Performance: The use of pasture pens has been documented at operations with
1,000 birds but is believed to be used most commonly at operations with fewer than 1,000 birds.
Lee (2000) also indicates that pastured poultry operations require up to twice the amount of feed
as confined poultry does to achieve the same weight gain and/or production goal. All wastes
produced while the birds are on pasture is incorporated into the sod, and therefore results in
minimal waste requiring disposal.
Advantages and Limitations: Some of the advantages associated with pastured poultry versus
confinement housing are:
Pasture pens are easy and inexpensive to build;
Controlled moves will harvest grass and help spread manure uniformly across the field;
• Perimeter fencing is not required;
Diseases associated with confinement housing may be less likely to occur;
Waste management handling is reduced; and
Pasture-raised birds may have a higher market value (Lee, 2000).
The limitations associated with pastured poultry include the following:
The small pens hold relatively few poultry, compared with their cost;
Pens can trap heat, leading to heat stress;
The roof height of the pens istoo low for turkeys to stretch and raise their heads to full
height;
• Pens may be difficult to move; •
Pens offer only minimal protection from weather; and
Birds often have to bed down at night in manure-soaked grass (Lee, 2000).
Operational Factors: Pasture-based poultry operations require increased labor for animal
handling, feeding, and watering (Lee, 2000). This increased labor is partially offset by a decrease
in waste management.
Demonstration Status: No data could be found to indicate the number of pasture-based poultry
operations. However, the use of pasture pens is rarely observed at operations with more than
1,000 birds. Thus few if any pastured poultry operations confine sufficient numbers of birds to
be defined as CAFOs on the basis of operation size.
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8.2 Manure/Waste Handling, Storage, and Treatment Technologies
Waste from animal feeding operations includes manure, bedding material, and animal carcasses.
There are a variety of methods for handling, storing, and treating waste. Waste is handled in a
solid form and through the use of water. As stated in earlier chapters, some facilities use water to
move the waste away from the animals and then separate the solids from the liquids prior to
storage, treatment, and disposal. Storage and treatment of waste is done in the both the solid and
liquid/slurry forms.
8.2.1 Waste Handling Technologies and Practices
Different practices are used to handle or move liquid and solid wastes, and the choice of practices
depends on the type of housing configuration. Housing configurations include total confinement,
which is the most common and used almost exclusively in the poultry industry and at larger
swine operations, open buildings with or without outside access, and lots or pastures with a hut
or with no buildings.
Practice: Handling of Waste in Solid Form
Description: The use of hoop houses for swine and high-rise hog houses to handle manure in. a
dry form was discussed in section 8.1. In facilities with open lots, manure accumulates on the
ground as a solid that can be diluted by rainfall (mostly for beef and dairy; swine and poultry are
mostly totally confined) or by spillage from watering areas. Whether the lot is paved, partially
paved, or unpaved, manure is typically handled as a solid or slurry and is scraped with tractor
scrapers or front-end loaders and stored in a pile (see Figure 8-2). There are several options for
separating solid manure from the animals at confinement facilities. Solid, unslatted floors, both
paved and unpaved, can be hand-scraped or scraped with a tractor or front-end loader into a pile,
pit, or other storage facility. Sloped floors further aid in manure collection as animal traffic
works the manure downslope. Other facilities use uncovered alley or gutter systems combined
with hand scraping, automatic scraping, or sloped floors to collect manure. Scraped manure from
underslat gutters, alleys, or shallow pits can be held temporarily in a pit or a deep collection
gutter at one end of the building, from which it can be applied to the land or transferred to a more
permanent storage structure. •
Application and Performance: Solid systems are best suited for open lot facilities, especially in
areas that have a dry climate because exposed manure is less likely to be diluted by excess
rainfall. The choice of solid or liquid handling systems, however, has been historically based on
operator preference with respect to capital investment, labor requirements, and available
equipment and facilities.
Advantages and Limitations: Solid handling systems offer both advantages and disadvantages to
facility operators. For instance, solid systems use equipment that is already present at the facility,
such as tractors and front-end loaders. Tractors and front-end loaders are flexible, have fewer
mechanical problems, are less subject to corrosion, and work well on frozen manure, but they
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Solids storage
structure (optional)
Clem water
divetslon *^-—.
Figure 8-2. Manure Scraped and Handled as a Solid on a Paved
Lot Operation (from USDA NRCS, 1996)
require more labor than automatic scrapers. Solid systems are not as automated as liquid
systems; although they involve little or no capital investment and require less maintenance, they
require much more labor than mechanical scraper systems or flushing systems. An advantage to
solid systems is that the volume of manure handled is much less than the volume associated with
liquid systems, which translates into smaller storage facility requirements. Bedding can be used
without concern for pumping or agitating equipment problems (which are a concern for liquid
handling systems).
Operational Factors: The extent of paving on an open lot determines the care with which
manure is removed. Unpaved lots develop an impervious layer from bacterial activity and hoof
action, and this layer protects against soil loss and percolation of liquids. Also, scraping of
unpaved surfaces incorporates sand and soil into the manure, which can cause problems with
storage or treatment of the manure. If scraped manure is to be stacked, it may be necessary to
add an appreciable amount of bedding to attain a more solid consistency.
Demonstration Status: Solid handling systems are fairly common at smaller swine operations.
According to Swine '95 (USDA APHIS, 1996), removal of manure by hand is used most often in
all types of operations (farrowing 38.2 percent, nursery 29.9 percent, and grower-finisher 27.2
percent). Mechanical scrapers and tractors are also used for solids handling (farrowing 12.0
percent, nursery 17.6 percent, and grower-finisher 24.9 percent).
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Poultry waste is mostly handled as a dry litter, the exception being layer operations, particularly
in the South region (USDA NAHMS, 2000a).
Manure is often handled in solid form at smaller dairy farms. According to Dairy '96 (USDA
APHIS, 1996A), gutter cleaners are used most often to remove manure from dairy cow housing
areas (63.2 percent). Mechanical scrapers or tractors are frequently used to clean alleys (57.7
percent), A number of dairies store manure in solid form: 79.2 percent of dairies with fewer than
100 cows and 59.5 percent of dairies with 200 or more cows are reported to use some form of
solid waste storage (USDA APHIS, 1996B).
Scraping is the most common method of collecting solid and semisolid manure from beef barns
and open lots. Solids can be moved with a tractor scraper and front-end loader. Mechanical
scrapers are typically used in the pit under barns with slotted floors. Scraping is common for
medium and large feedlots. (Loudon, 1985)
Practice: Teardrop, V- and Y-ShapedPits With Scraper
Description: Confinement facilities have several manure collection options for separating
manure liquids from manure solids. Several underfloor gutter systems that are applicable only to
swine will be discussed. Np comparable manure collection systems that separate liquids and
soUds are known for other animal species.
The reason for separating swine manure into solids and liquids is to concentrate pollutants and
nutrients. Kroodsma (1985) installed a plastic 0.78 mm filter net under the floor of a pig house
in which eight pigs were fed by wet feeders so that no excess water fell into the manure. Solids
fell onto the screen and liquids passed through. The results showed that the relatively
undisturbed feces contained about 80 percent of the biological oxygen demand (BOD), chemical
oxygen demand (COD), total solids (TS), phosphorus (P), calcium (Ca), magnesium (Mg), and
copper (Cu). Sixty per cent of the total kjeldahl nitrogen (TKN) and forty percent of the
potassium (K.) were also retained in the filter net. Thus, if solids can be recovered relatively
intact, parameters such as nutrients will be concentrated.
Two gutter configurations that may be useful for swine operations are Y-shaped and V-shaped.
gutters under slatted floors (Tengman, et al., undated draft). The sloping sides of the gutters
facilitate retention of solids and allow liquids to drain to the center collection area. Scrapers pull
the solids to one end of the barn for solids handling, while liquids flow with gravity in the
opposite direction for management in a liquid manure system.
V-shaped gutters are easier to build than Y-shaped gutters and may be easier to clean. Manure
movement in v-shaped gutters is not substantially different than in y-shaped gutters. The
sideslope of Y- or V-shaped gutters should be 1:1 for farrowing operations and 3/4:1 for
nurseries. A slope of 1:240 to 1:480 is recommended for the liquid gutter (Tengman, et al.,
undated draft).
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Manure that is scraped from underslat gutters, alleys, or shallow pits can be held temporarily in a
pit or a deep collection gutter at one end of the building, from which it can be applied to the land
or transferred to a more permanent storage structure.
Application and Performance: The choice of a manure handling system is based primarily on
operator preference with respect to capital investment, labor requirements, and available
equipment and facilities. Demonstration of the economic viability or the value of concentrating
nutrients using the Y-shaped gutter and V-shaped gutter is apparently lacking. No performance
data was found from full-scale demonstration of the segregation.of constituents, including
pathogens, metals, growth hormones, and antibiotics.
Advantages and Limitations: The advantage in using a Y-shaped or V-shaped scrape collection
system would be the concentration of nutrients in the solids. Nutrients concentrated in solid form
are cheaper to haul than in slurry form because water, which would increase the weight and
volume, is not added. Disadvantages include reduced air quality in hog buildings over manure
solids smeared on the collection slope, repair of cable scrapers in small spaces under slatted
floors with hogs present, the need for the operator to manage both a compost or solids stacking
operation with solids handling equipment and a liquid storage and application system with liquid
handling equipment.
Operational Factors: Climate, temperature, and rainfall generally do not affect scraper systems
in hog barns. If scraped manure solids are to be stacked or composted, it may be necessary to add
an appreciable amount of bedding to attain a more solid consistency.
Demonstration Status: Underslat manure scrape and gutter systems to direct manure liquids and
solids to different handling systems have been developed, but they are not commonly used.
Practice: Handling of Waste in Liquid Form
Description: Liquid handling systems are the alternative to scraping and hauling manure. They
are especially common in confinement housing operations because it is easier to install
automated systems inside new or existing structures and it is more difficult to maneuver tractors
or front-end loaders for scraping in small pens and tight corners. Excreted manure can be
collected in shallow, narrow, open gutters or alleys, or it can collect under slats in gutters or pits
for periodic flushing to a more permanent storage or treatment facility. The manure can also be
directly applied to land without extended storage or treatment.
Slotted floors are an efficient method for removing manure from animal areas. Floors tend to be
typically partially slotted over a pit or gutter. Feeding and resting areas are located on solid
floors, and watering areas are placed over slotted floors. Manure is worked through the slats by
hoof action and is stored beneath the slats until it is pumped or flushed to a lagoon. Fresh water
can be used for flushing or water from a secondary lagoon can be recycled as flush water. An
example of a slotted floor system is shown in Figure 8-3.
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Figure 8-3. Fed hogs in confined area with concrete floor and tank
storage liquid manure handling (from USD A NRCS, 1996).
Application and Performance: Liquid manure systems are most frequently used for large animal
facilities, where the automation of waste management systems is very important. They may also
be preferred where water is abundant or when rainfall on open lots causes considerable dilution
of manure solids. Liquid systems are especially appropriate when spray irrigation of nutrient-
laden waters is the preferred method for fertilizing and watering crops.
Advantages and Limitations: Flushing systems with liquid manure handling are less labor-
intensive and more automated than solid handling systems, but the volume of manure and water
to be stored, treated, and disposed of is greater. Flushing systems require large volumes of water
to be pumped and stored in a sump until discharged by gravity flow or pumped to a lagoon.
Consequently, where water is a valuable commodity, liquid systems might not be economical.
This limitation can be offset by recycling flush water from treatment lagoons. Equipment needed
for liquid systems, including sumps, pumps, agitators, choppers, and sprayers, brings with it high
capital, operating, and maintenance costs, although savings may be seen in decreased labor costs.
Manure consistency is very important in liquid handling systems because the equipment can be
damaged by fibrous material (bedding), sand, or other foreign materials. Periodic cleanout of
solids is necessary to maintain the capacity and proper functioning of storage structures and
handling equipment.
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Operational Factors: Slats can be made of wood, concrete, steel, aluminum, or plastic.
Concrete is the most sturdy material, is the least corrodible, and handles the weight of larger
animals, but it requires extra supports and the initial costs are higher than the costs of other
materials. Wood is the least expensive material, but it can be chipped by the animals and needs
to be replaced at least every 2 to 4 years. Plain steel and aluminum slats are subject to corrosion,
but they can be galvanized or coated with paint or plastic to extend their life. Plastic slats, metal
grates, expanded metal mesh, and stainless steel slotted planks are appropriate for swine
farrowing and nursery operations that house smaller pigs. Openings between slats should be
greater than 3/4 inch, up to 1 3/4 inches for swine operations.
Demonstration Status: The Swine '95 report (USDA APHIS, 1996) demonstrates that liquid
systems, although not the most common type on a facility-by-facility basis, are still used fairly
frequently. Flushing under slats accounts for 5.3 percent of farrowing, 9.4 percent of nursery,
and 2.4 percent of grower-finisher operations, whereas flushing with open gutter systems
accounts for 3.0,2.1, and 3.4 percent of each operation type, respectively. Liquid handling
systems are becoming increasingly popular as larger operations become more prevalent,
necessitating automated systems for manure handling.
Poultry waste is mostly handled as a dry litter, the exception being layer operations, particularly
those in the South region. Approximately 40 percent of the laying operations in the South use a
flush system with a lagoon (USDA NAHMS, 2000a).
Dairy '96 (USDA APHIS, 1996A) reports that a small number of dairy farms, 2.8 percent, use
water to remove manure from alleys. However, over 90 percent of operations with 200 or more
cows are reported to use liquid manure storage systems (USDA APHIS, 1996B). According to
the NAHMS survey results (Garber, 1999), approximately 50% of all facilities with greater than
500 mature dairy cows employ flushing as a means of cleaning the housing area.
A flushing system dilutes manure from beef feedlots with water to allow for automated handling.
The system uses a large volume of water to flush manure down a sloped gutter to storage, where
the liquid waste can be transferred to a storage lagoon or basin. This system is not common for
large beef feedlots; however, this type of system is widely used at veal operations (Loudon,
1985). Based on EPA site visits, about 67 percent of veal operations flush manure to liquid
lagoon storage systems.
Practice: Berms and Storm Water Diversions
Description: "Clean" storm water runoff from land surrounding livestock facilities can be
diverted from barns, open animal concentration areas, and waste storage or treatment facilities to
prevent mixing with wastewater. This is accomplished through earthen perimeter controls and
roof runoff management techniques.
Earthen perimeter controls usually consist of a berm, dike, or channel constructed along the
perimeter of a site. Simply defined, an earthen perimeter control is a ridge of compacted soil,
often accompanied by a ditch or swale with a vegetated lining, located at the top or base of a
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sloping area. Depending on their location and the topography of the landscape, earthen perimeter
controls can achieve one of three main goals: preventing surface runoff from entering a site,
diverting manure-laden runoff created on site to off-site waste trapping devices, and intercepting
"clean" storm water runoff and transporting it away from lagoons or belowground tanks.
Therefore, diversions are used to protect areas from runoff and divert water from areas where it is
in excess to locations where it can be stored, used, or released. Thus, it prevents the mixing of
"clean" storm water with manure-laden wastewater, reducing the volume of wast water to be
treated.
Roof runoff management techniques such as gutters and downspouts direct rainfall from roofs
away from areas with concentrated manure. Because these devices prevent storm water from
mixing with contaminated water, they also reduce the volume of wastewater to be treated.
Application and Performance: Earthen perimeter controls or diversions are applicable where it is
desirable to divert flows away from barns, open animal concentration areas, and waste storage or
treatment facilities. They can be erected at the top of a sloping area or in the middle of a slope to
divert storm water runoff around a feeding or manure storage site. However, unvegetated,
earthen channels should not be used in regions of high precipitation because of potential erosion
problems.
The design capacity of a channel is calculated using Manning's equation and is based on
precipitation, slope, wetted perimeter, water cross-sectional area, and surface roughness. Water
velocity is also a consideration in designing diversions to minimize erosion. Other types of
diversions that can be used for runoff control include grassed waterways, which are natural or
constructed channels that provide stable runoff conveyance, and lined waterways or outlets,
which are lined channels or outlets reinforced with erosion-resistant linings of concrete, stone, or
other permanent materials to provide additional stability.
Advantages and Limitations: When properly placed and maintained, earthen perimeter controls
are effective for controlling the velocity and direction of storm water runoff. Used by
themselves, they do not have any ability to remove pollutants and thus must be used in
combination with an appropriate sediment or waste trapping device at the outfall of the diversion
channel. With these diversion techniques, storm water runoff is prevented from mixing with
contaminated manure-laden wastewater and thus the volume of water for treatment is
decreased;.however, the concentrated runoff in the channel or ditch has increased erosion
potential. To such erosion, diversion dikes must be directed to sediment trapping devices where
erosion sediment can settle out of the runoff before being discharged. In addition, if a diversion
dike crosses a vehicle roadway or entrance, its effectiveness may be reduced. Wherever possible,
diversion dikes should be designed to avoid crossing vehicle pathways.
Operational Factors: The siting of earthen perimeter controls depends on the topography of the
.area surrounding a specific site. When determining the appropriate size and design of these
diversion channels, the shape of the surrounding landscape and drainage patterns should be
considered. Also, the amount of runoff to be diverted, the velocity of runoff in the diversion, and
8-52
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the credibility of soils on the slope and within the diversion channel or swale are essential design
considerations.
Both diversion channels and roof management devices must be maintained to remain effective.
If vegetation is allowed to grow in diversions, the roughness increases and the channel velocity
decreases which can cause channel overflow. Therefore, vegetation should be periodically
mowed. In addition, the dike should be maintained at the original height, and any decrease in
height due to settling or erosion should be remedied.
Roof management devices such as gutters and downspouts must be cleaned and inspected
regularly to prevent clogging and to ensure its effectiveness.
Demonstration Status: The use of earthen perimeter techniques such as berms, diversions, and
channels and the use of roof management techniques to divert storm water away from bams,
open animal concentration areas, and waste storage or treatment facilities are well-accepted
practices that prevent "clean" wastewater from mixing with manure-laden wastewater, thus
reducing the volume of wastewater to be treated.
8.2.2 Waste Storage Technologies and Practices
The USDA NRCS recommends that storage structures be designed to handle the volume of
manure produced between emptying events. The minimum storage period is based on the timing
required for environmentally safe waste utilization considering climate, crops, soil, equipment,
and local, state, and federal regulations. The design storage volume for liquid manure should
account for manure, wastewater, precipitation and runoff (if uncovered), and other wastes that
will accumulate during the storage period, such as residual solids that are not removed when
liquids are pumped. Other general considerations are inlet designs, outlets or pumping access,
and safety (such as fencing, odor and gas control, reinforcement against earth movements and
hydrostatic pressure, use of a cover, and amount of freeboard).
Practice: Anaerobic Lagoons
Description: Anaerobic lagoons are earthen basins that provide storage for animal wastes while
decomposing and liquefying manure solids. Anaerobic processes degrade high biochemical
oxygen demand (BOD) wastes into stable end products without the use of free oxygen.
Anaerobic lagoons are designed based on volatile solids loading rates (VSLR). Volatile solids
are the wastes that will decompose. The volume of the lagoon consists of the following (see
Figure 8-4):
1. Minimum Treatment Volume—The total daily volatile solids from all waste sources
divided by the volatile solids loading rate for a particular region. The minimum treatment
volume is based on the volatile solids loading rate, which varies with temperature and
therefore with geographic location. Recommended volatile solids loading rates in the
United States vary from 3 to 7 pounds per 1,000 ft3 per day.
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2. Sludge Volume—Volume of accumulated sludge between cleanouts. A fraction of
the manure solids settles to the bottom of the lagoon and accumulates as sludge. The
amount of sludge accumulation depends on the type and amount of animal waste.
3. Manure and Wastewater Volume—The volume of manure and wastewater transferred.
from feedlot operational facilities to the lagoon during the storage period. Lagoons are
typically designed to store from 90 to 365 days of manure and wastewater.
4. Net Precipitation—Precipitation minus the evaporation during the storage period.
5. Design Storm—Typically a 25-year, 24-hour storm event.
6. Freeboard—A minimum of 1 foot of freeboard. Freeboard is the extra depth added to the
pond as a safety factor. .
7. Runoff—The runoff volume from lagoon berms. In general, lagoons should not receive
runoff because runoff can shock the lagoon with an overload of volatile solids. Some
runoff will enter the lagoons from the berms surrounding them.
Anaerobic lagoons should be at least 6 to 10 feet deep, although 8- to 20-foot depths are typical.
Deeper lagoons require a smaller surface area, and they more thoroughly mix lagoon contents as
a result of rising gas bubbles and minimize odors. Lagoons are typically constructed by
excavating a pit and building berms around the perimeter. The berms are constructed with an
extra 5 percent in height to allow for settling. The sides of the lagoon should be sloped with a
2:1 or 3:1 (horizontahvertical) ratio. Lagoons can be designed as single-stage or multiple-stage
(usually two stages). Two-stage lagoons require greater total volume but produce a higher
quality lagoon effluent •
Lagoon covers can be used to control odor and collect biogas produced from the natural
decomposition of manure. Covers are usually made of a synthetic material, and are designed to -
float on the surface of the lagoon. Often, because of the large size of the lagoon, the cover is
constructed in multiple modules. Each module has flotation devices at the corners to help support
the cover, and is tied down at the edge of the pond or lagoon. Covers typically have drains
constructed hi them to allow rainwater to drain through to the lagoon.
Lagoons are sometimes used in combination with a solids separator, typically for dairy waste.
Solids separators help control the buildup of nondegradable material such as straw or other
bedding materials. These materials can form a crust on the surface of the lagoon, which
decreases its activity.
Application and Performance: Anaerobic lagoons provide effective biological treatment of
animal wastes. Anaerobic lagoons can handle high pollutant loads while minimizing manure
odors. Nondegradable solids settle to the bottom as sludge, which is periodically removed. The
liquid is applied to cropland as fertilizer or irrigation water or is transported off site. Properly
managed lagoons will have a musty odor. Anaerobic processes decompose faster than aerobic
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processes, providing effective treatment of wastes with high BOD, such as animal waste.
Anaerobic lagoons are larger than storage ponds because additional volume is needed to provide
biological treatment; however, since a constant oxygen concentration is not required, anaerobic
lagoons are generally smaller than aerobic lagoons.
Lagoons reduce the concentrations of both N and P in the liquid effluent. Phosphorus settles to
the bottom of the lagoon and is removed with the lagoon sludge. Approximately 60 percent of
the influent N is lost through volatilization to ammonia (Fulhage, Van Horn). Microbial activity
converts the organic N to ammonia N. Ammonia N can be further reduced to elemental nitrogen
(Ny and released into the atmosphere. Lagoon effluent can be used for land application or
flushing of animal barns, or can be transported off site. The sludge can also be applied to land
provided the soil is not saturated with nutrients. Information on the reduction of BOD,
pathogens, and metals in lagoons is not available. Reductions in chemical oxygen demand, total
solids, volatile solids, total N, P, and potassium are presented in Table 8-10.
Table 8-10. Anaerobic Unit Process Performance
Anaerobic Treatment
Pull plug pits
Underfloor pit storage
Open top tank
Open pond
Heated digester effluent prior to
storage
Covered first cell of two cell
lagoon
One-cell lagoon
Two-cell lagoon
HRT
days
4-30
30-180
30-180
30-180
12-20
30-90
>365
210+
COD
TS
VS
TN
P
K
Percent Reduction
—
—
—
—
35-70
70-90
70-90
90-95
0-30
30-40
— •
—
25-50
75-95
75-95
80-95
0-30
20-30
—
—
40-70
80-90
75-85
90-98
0-20
5-20
25-30
70-80
0
25-35
60-80
50-80
0-20
5-15
10-20
50-65
0
50-80
50-70
85-90
0-15
5-15
10-20
40-50
0
30-50
30-50
30-50
HRT=hydraulic retention time; COD=chemical oxygen demand; TS=total solids; VS=volatile solids; TN=total
nitrogen; P=phosphorus; K= potassium; — =data not available.
Source: Moser and Martin, 1999
Advantages and Limitations: Anaerobic lagoons offer several advantages over other methods of
storage and treatment. Anaerobic lagoons can handle high pollutant loads and provide a large
volume for long-term storage. They stabilize manure wastes and reduce N content through
biological degradation. Lagoons allow manure to be handled as a liquid, which reduces labor
costs. If lagoons are located at a lower elevation than the animal barns, gravity can be used to
transport the waste to the lagoon, which further reduces labor. Mild climates are most suitable
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for lagoons; cold weather reduces the biological activity of the microorganisms that degrade the
wastes. Lagoons can experience spring and fall turnover, in which the more odorous bottom
material rises to the surface. Foul odors can also result if biological activity is reduced or if there
is a sudden change in temperature or pollutant loading rate.
Operational Factors: To avoid ground water and soil contamination, several factors must be
considered. The lagoon should be located on soils with low to moderate permeability or on soils
that can form a seal through sedimentation and biological action (NRCS). Impervious barriers or
liners are used to reduce seepage through the lagoon bottom and sides and are described in the
following practice.
Lagoon inlets should be designed from materials that resist erosion, plugging, and freezing.
Vegetation around-the pond should be maintained to help stabilize embankments.
Lagoons must be properly maintained for effective treatment. The minimum treatment volume
of the lagoon must be maintained. Lagoons work best when the influent flow is a steady, gradual
flow rather than a large slug flow., The pH of the lagoon should be monitored. The optimum pH
for lagoon treatment is about 6.5, which maximizes the activity level of the bacteria. Lime can
be added to the lagoon to increase pH to this level. Also, since the rate of volatile solids
decomposition is a function of temperature, the acceptable volatile solids loading rate varies with
climate. The loading rate should be monitored to ensure that it is appropriate to the region in
which the lagoon is located.
Demonstration Status: Anaerobic lagoons without covers are used at 20.9 percent of all grower-
finisher swine operations. Of these, swine operations with 10,000 or more head use uncovered
lagoons most frequently (81.8 percent) (USDA APHIS, 1996). Lagoons are used on egg-laying
farms in warmer climates. Beef facilities typically use storage ponds rather than lagoons.
NAHMS estimates that 1.1 percent of dairies with more than 200 head use anaerobic lagoons
with a cover and 46.7 percent use anaerobic lagoons without a cover (USDA APHIS, 1996b).
The use of lined lagoons is dependent on site-specific conditions.
Practice: Lagoon Liners
Description: Lagoon liners are impervious barriers used to reduce seepage through the lagoon
bottom and sides.
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Application and Performance: Soil that is at least 10 percent clay can be compacted with a
sheepsfoot roller to create a suitable impervious barrier. If the soil is not at least 10 percent clay,
a liner or soil amendment should be used. There are also site conditions that may require seepage
Freeboard (1.0 minimum)
Depth of 25-year, 24-hour storm event
Depth of normal precipitation less evaporation
Manure and wastewater volume
Minimum treatment volume
Sludge volume
Figure 8-4. Cross Section of Anaerobic Lagoons
(Source: USDA NRCS, 1998)
reduction beyond what is provided by compacting the natural soil. These conditions may
include a shallow underlying aquifer, an underlying aquifer that is ecologically important or used
as a domestic water source, or highly permeable underlying bedrock or soil. There are three
options available to provide additional seepage reduction. First, the soil can be mixed with
bentonite or a soil dispersant and then compacted. Clay can be imported from another area and
compacted along the bottom and side walls. Last, concrete or synthetic materials such as
geomembranes or geosynthetic clay liners can be used.
Advantages and Limitations: Concrete and synthetic liners are usually the most expensive.
Operational Factors: The method chosen to line the lagoon depends on the type of soil, site
geography and location, available materials, and economics.
Demonstration Status: The use of lined lagoons depends on site-specific conditions.
Practice: Storage Ponds
Description: Waste storage ponds are earthen basins used to store wastes temporarily, including
runoff, solids (e.g. manure), and wastewater. The total volume of the pond consists of the
following (see Figure 8-5):
1. Sludge Volume—Volume of accumulated sludge between cleanouts. A fraction of the
manure solids settles to the bottom of the pond and accumulates as sludge. The amount
of sludge accumulation depends on the type and amount of animal waste.
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2. Manure and Wastewater Volume—The volume of manure and wastewater from feedlot
operational facilities transferred to the pond during the storage period. Ponds are
typically designed to store from 90 to 270 days of manure and wastewater. The
percentage of solids in the influent will depend on animal type and the waste management
system.
3. Runoff—The runoff from the sites (usually the drylot area at animal feeding operations).
4. Net Precipitation—Precipitation minus the evaporation for the storage period.
5. Design Storm—Typically a 25-year, 24-hour storm event.
6. Freeboard—A minimum of 1 foot of freeboard. Freeboard is the extra depth added to the
pond as a safety factor.
Ponds are typically rectangular in shape and are constructed by excavating a pit and building
berms around the perimeter. The berms are constructed with an extra 5 percent in height to allow
forsettling. The sides of the pond are typically sloped with a 1.5:1 or3:l (horizontal:vertical)
ratio. .
Ponds are typically used in combination with a solids separator. Solids separators help control
buildup of material such as straw or other bedding materials on the surface of the pond.
Pond covers can be used to control odor and collect biogas produced from the natural
degradation of manure. Covers are usually made of a synthetic material, and are designed to float
on the surface of the impoundment. Often, because of the large size of the pond, the cover is
constructed in multiple modules. Each module has flotation devices at the comers to help support
the cover, and is tied down at the edge of the pond. Covers typically have drains constructed in
them to allow rainwater to drain through to the pond.
Application and Performance: Waste storage ponds are frequently used at animal feeding
operations to contain wastewater and runoff from contaminated areas. Manure, process water,
and runoff are routed to these storage ponds, where the mixture is held until it can be used for
A
" V-
Required \
vnlnma \
Freeboard
Depth of 25-year, 24-hour storm event
Depth of normal precipitation less evaporation
/
17
7.
\
Manure and wastewater volume
Sludge volume
^—J
1
I
Figure 8-5. Cross Section of Waste Storage Pond (Source: USDA 1996)
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irrigation or transported off site. Solids settle to the bottom as sludge, which is periodically
removed. The liquid is applied to cropland as fertilizer or irrigation water, or is transported off
site.
Storage ponds hold wastewater and manure and are not intended to actively treat the waste.
Because they do not require additional volume for treatment, storage ponds are smaller hi size
than treatment lagoons.
Ponds reduce the concentrations of both N and P in the liquid effluent. Phosphorus settles to the
bottom of the pond and is removed with the sludge. Influent N is reduced through volatilization
to ammonia. Pond effluent can be used for land application or flushing animal barns, or it can be
transported off site. The sludge can also be applied to the land provided the soil is not saturated
with P.
Advantages and Limitations: Storage ponds provide a large volume for long-term waste storage
and allow manure to be handled as a liquid. If ponds are located at a lower elevation than the
animal barns, gravity can be used to transport the waste to the pond, which minimizes labor.
Although ponds are an effective means of storing waste, no treatment is provided. Because
ponds are open to the air, ;odor can be a problem.
Operational Factors: To avoid ground water and soil contamination, several factors must be
taken into consideration. Impervious barriers or liners are used to reduce seepage through the
pond bottom and sides. Soil that is at least 10 percent clay can be compacted with a sheepsfoot
roller to create a suitable impervious barrier. If the soil is not at least 10 percent clay, a liner or
soil amendment should be used. There are also site conditions that may require seepage
reduction beyond what is provided by compacting the natural soil. Conditions may include a
shallow underlying aquifer, an underlying aquifer that is ecologically important or used as a
domestic water source, or highly permeable underlying bedrock or soil. There are three options
available to provide additional seepage reduction. First, the soil can be mixed with bentonite or a
soil dispersant and then compacted. Clay can be imported from another area and compacted
along the bottom and side walls. Last, concrete or synthetic materials such as geomembranes or
geosynthetic clay liners can be used. Concrete and synthetic liners are usually the most
expensive. The method chosen to line the pond depends on the type of soil, site geography and
location, available materials, and economics.
Pond inlets should be designed from materials that resist erosion, plugging, and freezing.
Vegetation around the pond should be maintained to help stabilize embankments.
Demonstration Status: Ponds are a common method of waste storage for swine, beef, and dairy
facilities and are used on poultry farms in warmer climates. Beef feedlots tend to use storage
ponds for collection of runoff from the drylots. EPA estimates that 50 percent of the medium-size
(300-1000 head) beef feedlots in all regions and 100 percent of the large-size (>1,000 head) beef
feedlots in all regions have a storage pond for runoff. NAHMS estimates 27.8 percent of dairies
use earthen storage basins (USDA APHIS, 1999). The use of lined ponds depends on site-
specific conditions.
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Practice: Pit Storage . •
Description: Manure pits are a common method for storing animal wastes. They can be located
inside the building underneath slats or solid floors, or outside and separated from the building.
Typical storage periods range from 5 to 12 months, after which manure is removed from the pit
and transferred to a treatment system or applied to land. There are several design options for pit
storage. For example, shallow pits under slats provide temporary storage and require more
frequent manure removal to longer-term storage or for land application. Pit recharge systems,
which are common in the Midwest, involve regularly draining the pit contents to a lagoon and
recharging the pit with fresh or recycled water. The regular dissolution of solids keeps the pits
free of excessive buildup while providing temporary storage for manure. Pit recharge systems
typically have level floors with an average depth of 12 inches of recharge water, 12 inches
allowed for waste accumulation, and 12 inches of air space between the pit surface and the
slatted floor.
Application and Performance: Because agitating and pumping equipment does not handle solid
or fibrous materials well, manure with greater than 15 percent solids will require dilution. ,
Chopper-type agitators maybe needed to break up bedding or other fibrous materials that might
be present in the pit.
Advantages and Limitations: Below-floor storage systems provide ease of collection and
•minimize volume while maximizing fertilizer value, but they may cause a buildup of odors and
gases and can be difficult to agitate and pump out. Remote storage avoids odor and gas buildup
in animal housing areas and provide options for methane production and solids separation, but
entails additional costs for transfer from the housing facilities to storage.
Operational Factors: Pits must have access for pumping equipment, and outside pits must be
covered or fenced to prevent accidental entry into the pit. They should be designed to withstand
anticipated hydrostatic, earth, and live loads as well as uplifting in high-water-table areas. Before
the pit is filled with manure, water is typically added to prevent solids from sticking to the pit
floor. Depths range from 3 to 4 inches under slatted floors and 6 to 12 inches if manure is
scraped and hauled to the pit. Sand should not be used as a bedding material because it is
incompatible with pumping systems. The pits should always be free of nails, lumber, or other
foreign material that can damage equipment.
Demonstration Status: Pit holding is mostly done at .swine operations. Swine 'PJ(USDA-
APHIS, 1996) reports that pit holding accounts for 25.5, 33.7, and 23.2 percent of farrowing,
nursery, and grower-finisher operations, respectively.
Below-floor slurry or deep pit storage is reported in Dairy '96 (USDA APHIS, 1996b) at 7.9
percent of all dairy operations. Based on EPA site visits, about 33 percent of veal operations are
believed to utilize pit storage-systems. Beef feedlots do not typically utilize pit storage.
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Practice: Belowground or Aboveground Storage Tanks
Description: Belowground and aboveground storage tanks are used as an alternative to undei>
building pit storage and earthen basins. Both aboveground and belowground tanks are
commonly constructed of concrete stave, reinforced monolithic concrete, lap or butt joint coated
steel, or spiral wound coated steel with concrete floors. Current assembly practices for .
aboveground storage facilities are primarily circular silo types and round concrete designs, but
the structures may also be rectangular. Belowground storage can be located totally or partially
below grade. All storage tanks must be engineered to withstand operational constraints,
including internal and external hydrostatic pressure, flotation and drainage, live loads from
equipment, and loads from covers and supports. Belowground tanks should be surrounded by
fences or guardrails to prevent people, livestock, or equipment from accidently entering the tank.
When located directly adjacent to the animal housing facility, belowground tanks are easily filled
by scraping directly into the tank. In those situations where the storage tank is not adjacent to the
animal housing facility, a collection pit or sump is necessary for loading. In these systems a large
piston or pneumatic manure pump forces waste through a large-diameter underground pipe.
Aboveground tanks at a lower grade than the livestock housing facility can often be gravity-fed
through a similar underground pipe. The tank can be loaded from the top or bottom. Bottom
loading in aboveground tanks is most appropriate for manure that forms a surface crust, such as
cattle manure. The inlet pipe is usually located 1 to 3 feet above the bottom of the tank to
prevent blockages from solids. An advantage to bottom loading is that it pushes solids away
from the inlet pipe and distributes them more evenly. Top loading is suitable and most common
for manures that do not crust (i.e., liquid swine manure); however, top loading in an aboveground
system requires that manure be pumped against gravity. Figure 8-6 shows a typical aboveground
storage tank.
Application and Performance: Aboveground or belowground tanks are suitable for operations
handling slurry (semisolid) or liquid manure. This generally excludes open-lot waste which is
inconsistent in composition and has a higher percentage of solids. Furthermore, because of the
high cost of storage volume, prefabricated storage tanks are generally used to contain only waste,
but not runoff, from the livestock facility.
Belowground and aboveground storage tanks are appropriate and preferred alternatives in
situations where the production site.has karst terrain, space constraints, or aesthetics issues
associated with earthen basins. Storing manure in prefabricated or formed storage tanks is
especially advantageous on sites with porous soils or fragmented bedrock. Such locations may
be. unfit for earthen basins and lagoons out of concern that seepage and ground water
contamination may occur. Construction of formed storage tanks often includes installation of a
liner beneath the concrete to prevent seepage. Aboveground formed storage facilities allow
visual monitoring for leaking. Aboveground tanks may exhibit unsightly leaks at seams, bolt
holes, or joints, but these are usually quickly sealed with manure. In these storage systems the
joint between the foundation and sidewall is the greatest concern. Leaching and ground water
contamination can occur if the tank is not sealed properly.
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Figure 8-6. Aboveground Waste Storage Tank (from USDA NRCS, 1996).
Proper operational practices to maintain adequate, storage tank capacity between land
applications are critical. The holding volume of a storage tank consists of five fractions: residual
volume, manure/waste storage volume (bedding, wasted feed, water added for manure handling),
wash water volume, net rainfall and evaporation change, and freeboard capacity. .
In general, large amounts of water are not added during the handling of manure that is stored in
an aboveground or belowground storage tank. Installation costs usually dictate that capacity be
limited to manure storage requirements. Thus, water conservation is often practiced by facilities
that use aboveground or belowground storage tanks. For these facilities, recycling of wastewater
is not an option because the manure is generally in slurry form with more than 4 percent solids.
Aboveground and belowground storage tanks are simply storage facilities, and they do not
facilitate treatment of the manure. Thus, there is little to no effect on the reduction of nutrients,
pathogens, solids, heavy metals, growth hormones, or antibiotics. Nitrogen in liquid manure is
predominately in the inorganic form. This allows for some ammonia volatilization into the
atmosphere and a reduction in the total amount of N.
Advantages and Limitations: When these systems are used, manure agitation is necessary before
the contents of the storage structure are pumped into a tanker wagon for land application.
Agitation ensures uniform consistency of manure and prevents the buildup of solids, thus
maintaining the storage capacity of the tank. Agitation results hi a more even distribution of
nutrients in the manure prior to land application. It can be accomplished with high-horsepower,
propeller-type agitators or by recirculating with a high-capacity pump. The length of time the
manure needs to be agitated depends on the size of the storage tank, the volume of manure it
contains, the percent of solids hi .the manure, and the type of agitator. Manure with up to 15
percent solids can be agitated and pumped. Because of the potential for agitation and pumping
problems, only small amounts of chopped bedding are recommended for use hi systems using
storage tanks. Some types of agitators have choppers to reduce the particle size of bedding and
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solids. Dilution with additional water may be necessary to reduce agitation problems. One
design variation places the pump in a sump outside the tank, using it for both agitation, and
pumpouts.
Manure in a storage tank undergoes some anaerobic decomposition, releasing odorous and
potentially toxic gases, such as ammonia and hydrogen sulfide. Methane is also produced.
Covers can be installed to interrupt the flow of gases up from the liquid surface into the
atmosphere. Types of covers range from polyethylene, concrete, or geotextile to biocovers such
as chopped straw. Various covers have been shown to reduce odors by up to 90 percent.
Furthermore, particular types of covers can be used as methane reservoirs to collect and contain
gases from the digestion process for disposal by flaring or converting to electrical power.
Moreover, certain covers can prevent rainwater dilution and accumulation of airborne silts and
debris. Finally, it is generally accepted that some types of covers control N volatilization into the
atmosphere and maintain the N content of the manure.
The installation costs associated with prefabricated storage tanks are high when compared with
other liquid manure-handling systems. Glass-lined steel tanks are typically associated with the
highest cost. The useful life of the tanks depends on the specific manufacturer and the operator's
maintenance practices. Once they have been installed, aboveground and belowground storage
tanks have a low labor requirement, especially when designed as a gravity feed system (Purdue
Research Foundation, 1994). •
Operational Factors: Specific storage structure designs will vary by state because of climate and
regulatory requirements. Pumping manure during freezing conditions can be a problem unless all
pipes are installed below the freezing level in the ground. Design considerations in these systems
include check valves if bottom loading is used, pumping power with respect to the maximum
head, and pipe friction from the pump to the storage.
Demonstration Status: Belowground and aboveground storage tanks are in use nationwide in
swine, poultry, and dairy operations. They are appropriate for use in all slurry-based manure
handling systems, including those with shallow-pit flush systems, belt or scrape designs, or open-
gutterflush systems.
Practice: Solid Poultry Manure Storage in Dedicated Structures
Description: In the broiler and turkey segments of the poultry industry, specially designed
pole-type structures are typically used for the temporary storage of solid poultry manure-
however, horizontal (bunker) silo-type structures are also used. Manure produced in "high-rise"
houses for caged laying hens does not require a separate storage facility if handled as a solid.
A typical pole-type storage structure is 18 to 20 feet high and 40 feet wide. The length depends
on the storage capacity desired but is usually a minimum of 40 feet. The structure will have a
floor of either compacted soil or concrete, the latter being more desirable but much more
expensive. The floor elevation should be at a height above grade that is adequate to prevent any
surface runoff from entering the structure. A properly sited structure will be oriented parallel to
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the direction of the prevailing wind. Equipment access will be through the lee side, which will
have no wall. The other three sides of the structure will have walls extending from the floor to a
height of 6 to 8 feet. "Experience has shown that a higher wall on the windward side of the
building excludes precipitation more effectively. Walls may be constructed using pressure-
treated lumber or reinforced concrete. Wooden trasses covered with steel sheets are most
commonly used for roofing, although plywood roof decking covered with composition shingles
is also an option. Manure is usually stacked to a height of 5 to 8 feet. Figure 8-7 shows three
types of permanently covered solid manure storage structures.
Horizontal silo-type storage structures are also used for the temporary storage of solid poultry
manure. These storage structures can be constructed using either post-and-plank or reinforced
concrete walls on three sides. Equipment access will be through the lee side which will have no
wall. Concrete walls can be poured in place or made with prefabricated sections that are
manufactured for horizontal silo construction. Wall height can be from as low as 3 to 4 feet to as
high as 8 to 10 feet if prefabricated concrete sections are used. Usually, there is a concrete floor.
Again, floor elevation should be sufficiently above grade to prevent surface runoff from entering
the structure. With this type of storage structure, 6-mil or heavier plastic is typically used to
cover the stored manure, but tarpaulins have also been used. As with horizontal silos, old tires
are commonly used to secure the cover, although ropes or cables can also be used. Manure is
usually stacked to a height of 5 to 8 feet.
Engineered
roof
trusses
Concrete walla
with end access
Momoslope
roof
Timber walls
with nlde aceetut
Figure 8-7. Roofed Solid Manure Storage (from USDA NRCS, 1996).
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In the broiler industry, total cleanouts of production facilities occur only after a minimum of 1
year of production. A total cleanout frequency of 2 to 3 years is not uncommon. Total cleanouts
may be more frequent for brood chambers, but the frequency depends on the cost and availability
of bedding material, the incidence of disease, the concentration of gaseous ammonia within the
production facility, and the policy of the integrator. Caked manure, also known as crust, is
removed after every flock, typically a period of 49 days for 4- to 5-pound broilers. Usually,
storage structures are designed only for the storage of this caked manure because most broiler
growers view the cost of a structure large enough to store manure and litter from a total cleanout
as prohibitively high. Because caked manure production varies with the type of bedding
material, type of watering system, and climatic conditions, storage requirements may vary from
farm to farm. Also, cake production increases with bedding age. Local experience is usually
relied upon to estimate storage requirements.
In the turkey industry, total cleanouts of brooder facilities occur after every flock to control
disease, but grow-out facilities typically are totally cleaned out only once a year. Again, most
turkey growers consider the cost of storage of the manure and bedding from a total cleanout of
grow- out facilities to be prohibitively high. Therefore, structures are typically sized only for the
storage of manure and bedding from brooder houses.
Application and Performance: The temporary storage of solid poultry manure in a dedicated
structure is applicable to all poultry operations at which birds are maintained on a bedding
material. Thus, this practice is applicable to all broiler and turkey operations and the small
fraction of egg-producing operations that do not house birds in cages. The combination of
manure and bedding generated in these operations has a moisture content of less than 50 percent,
usually 25 to 35 perqeht, and is handled as a solid. This practice is not necessary for caged laying
hens in high-rise housing because the production facility has a manure storage capacity of 1 or
more years. ,
When sized and managed correctly, storage of solid poultry manure in a dedicated structure will
allow for the most efficient use of plant nutrients in the manure for crop production. This
eliminates the potential for contamination of surface and ground waters resulting from open
stacking of manure or spreading during the fall, winter, and early spring and after crop
establishment, when there is no potential for crop uptake. When the stored manure is effectively
protected from precipitation, odor and fly problems are minimal. Odor can be a problem,
however, when the manure is removed from the storage structure and spread on cropland.
The storage of caked broiler litter and turkey brooder house manure and bedding reduces the
potential impact of these materials on surface and ground water quality; however, a substantial
fraction of the manure and bedding produced by these segments of the poultry industry is not
stored because the associated cost is viewed as prohibitive. The material resulting from the total
cleanout of broiler houses and turkey grow-out facilities is often stored temporarily in open piles
or spread at inappropriate times of the year. Thus, storage, as currently practiced, probably is not
as effective in reducing water quality impacts as is presently thought.
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Advantages and Limitations: A correctly sized and managed storage structure allows application
to cropland when nutrients will be most efficiently used, thus minimizing negative impacts on
surface and ground waters as noted above. If application to cropland is not a disposal alternative,
storage can facilitate off-site disposal other than application to cropland.
The principal disadvantage of storing solid poultry manure in a dedicated structure is the cost of
the structure and additional material handling costs. Currently, sources of government assistance
are available (e.g., cost-share funds available from local soil and water conservation districts) to
partially offset construction costs and encourage the adoption of this practice.
Operational Factors: Spontaneous combustion in stored poultry manure has been a problem and
has led to the recommendation that stacking height be. limited to 5 to 8 feet to avoid excessive
compaction. Fires in solid poultry manure storage structures, like silo fires, are extremely
difficult to extinguish and often lead to the total loss of the structure.
Demonstration Status: Permanent covered structures for storage of solid manure are used
extensively in the broiler and turkey segments of the poultry industry. In a 1996 survey of broiler
growers on the Dehnarva Peninsula, 232 of 562 respondents indicated that they used a permanent
storage structure (Michel et al., 1996).
Practice: Concrete Pads
Description: Concrete pads are used as semi-impermeable surfaces upon which to place waste.
The waste pile is often open to the environment, but it can be covered with a roof or plastic
sheeting to minimize exposure to the elements. Pads are often sloped to a central location to
allow for drainage of rainwater and runoff.
The design for concrete pads varies according to the type of waste it receives (wet or dry) Waste
that includes settled solids from a settling basin or solids separator has a high moisture content.
In this case, the concrete pad typically has at least two bucking walls to contain the waste and to
facilitate the loading and unloading of waste onto the pile. The design height of the waste pile
does not exceed about 4 feet, because of the semi-liquid state of the waste. For operations with
drier waste, the concrete pad typically does not have bucking walls, and the maximum height of
the manure pile is 15 feet, because the manure is drier and can be stacked more easily.
Figure 8-8 illustrates the design of a concrete pad (MWPS,1993; USDA NRCS, 1996). Concrete
pads are between 4 and 6 inches thick and are made of reinforced concrete to support the weight
of a loading truck. The concrete pad is underlain by 4 inches of sand and 6 inches of gravel. The
pad is sloped to divert storm water runoff from the pile to the on-site waste management facility,
such as a lagoon or a pond. Bucking walls, made of reinforced concrete, are 8 niches thick and 3
to 4 feet tall.
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Application and Performance: Concrete pads are used at animal feeding operations to provide a
surface on which to store solid and semi-solid wastes that would otherwise be stockpiled directly
on the feedlot surface. Manure scraped from dry lots and housing facilities and solids separated
from the waste .stream in a solids separator can be stored on a concrete pad.
The pads provide a centralized location for the operation to accumulate excess manure for later
use on site (e.g. bedding, land application) or transportation off site. A centralized location for
stockpiling the waste also allows the operation to better control storm water runoff (and
associated pollutants). Rainwater that comes into contact with the waste is collected on the
Concrete Pad
6'
(k+10)
4'
t
Reinforced
Concrete
Pad
Sand
Gravel
Bucking walls
Bucking Wall Cross Section
Assumed Shape of Manure
Pile for Sizing Pad
8" concrete wall
Reinforced w/#4 bars
16" o.c. Both ways
Space #4 bar
L anchors, 16° o.c.
Paraboloid of Revolution
L = length of base pile
L= length of top of pile
D - depth pf pile
v =
Figure 8-8 Concrete Pad Design
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concrete pad and is directed to a pond or lagoon and is thereby prevented from being released on
the feedlot. The pad also provides an impermeable base that minimizes or prohibits seepage of
rainfall, leaching pollutants or nutrients from the waste and infiltrating into the soil beneath it
The waste is not treated once it is on the concrete pad; the pad serves as a pollution prevention
measure. However, with regular handling of the waste, the N loads in the waste will be released
into the atmosphere through volatilization, and both N and P may be contained in runoff from the
pile after storm events. Pathogen content, metals, growth hormones, and antibiotics loads are not
expected to decrease significantly on the concrete pad unless the pile ages considerably.
Advantages and Limitations: An advantage to using a concrete pad for storage is to control
runoff and prevent waste from contaminating the surrounding environment. When rainwater or
precipitation comes into contact with the pile, the water may percolate through the pile, carrying
pollutants along the way. The water may exit the pile as runoff and carry pollutants to surface
waters or seep into the ground. The concrete pad and bucking walls niinimize this potential
seepage into and runoff onto the ground around the pile.
Depending on the duration of storage required, however, these pads can take up a very large area.
An operation may not have sufficient area to install a concrete pad large enough to store waste in
one place. It can also be expensive to construct a concrete pad large enough to accommodate the
amount of waste that would accumulate over an appropriate storage time.
Waste stored on a concrete pad will still need to be further managed, either by land application or
by transportation off site. There may be some odors from the pile on a concrete pad, but no more
than would be expected from any manure stored in a pile.
Operational Factors: Operations that frequently transport then: waste will require less storage
volume than operations that have less frequent hauling schedules. Operations requiring less
storage capacity will require a smaller pad area, resulting in lower capital costs.
Demonstration Status: Concrete pads are used relatively infrequently in the livestock industry.
They are more commonly used in dairies than hi poultry, beef or swine operations, because dairy
waste is semi solid and bucking walls are needed to contain the waste effectively, given the
higher moisture content. Waste from swine operations is generally too wet to stack on a pad, and
beef and poultry waste is usually piled directly on the feedlot.
8.2.3 Waste Treatment Technologies and Practices
8.2.3.1 Treatment of Animal Wastes and Wastewater
Some treatment systems store waste as well as change the chemical or physical characteristics of
the waste. Anaerobic lagoons are the most common form of treatment for animal feeding
operations. Other technologies use oxidation to break down organic matter. These include
aerated lagoons and oxidation ditches for liquids and composting for solids.
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Practice: Anaerobic Digesters for Methane Production and Recovery
Description: An anaerobic digester is a vessel that is sized both to receive a daily volume of
organic waste and to grow and maintain a steady-state population of methane bacteria to degrade
that waste. Methane bacteria are slow growing, environmentally sensitive bacteria that grow
wimout oxygen and require a pH greater than 6.5 to convert organic acids into biogas over time.
Anaerobic digestion can be simplified and grouped into two steps. The first step is easy to
recognize because,the decomposition products are volatile organic acids that have disagreeable
odors. During the second step, methane bacteria consume the products of the first step and
produce biogas—a mixture of carbon dioxide and methane—a usable fuel by-product A
properly operating digester will produce a gas with minimal odor because methane bacteria from
the second step reach a population large enough to rapidly consume the products of the first step.
There are three basic temperature regimes for anaerobic digestion: psychrophilic, mesophilic, and
thermophilic. Psychrophilic, or low-temperature, digestion is the natural decomposition path for
manures at temperatures found in lagoons. These temperatures vary from about 38 to 85 °F (3 .to
29 °C). The hydraulic retention time (HRT) required for stable operation varies from 90 days at
low temperatures to 30 days at higher temperatures. Methane production will vary seasonally
with the variation in lagoon temperature.
Maintaining a constant elevated temperature enhances methane production. Mesophilic digestion
cultivates bacteria that have peak activity between 90 and 105 °F (32 to 40 °C). Mesophilic
digesters operate at a retention period of 12 to 20 days. Thermophilic digesters promote bacteria
that grow at between 135 to 155 °F (57 to 68 °C); these digesters operate with a retention time of
6 to 12 days.
Although there are many types of anaerobic digesters, only covered lagoons operating at ambient
temperatures, complete-mix digesters, and plug-flow digesters can be considered commercially
available, because they are the only ones that have been implemented successfully at 10 or more
sites.
A cover can be floated on the surface of a properly sized anaerobic lagoon to recover methane.
Ideally, the cover is floated on the primary lagoon of a two-cell lagoon system, with the primary
lagoon maintained as a constant volume treatment lagoon and the second cell used to provide
storage of treated effluent until the effluent can be properly applied to land. The lagoons are not
heated, and the lagoon temperature and biogas production vary with ambient temperatures.
Coarse solids, such as hay and silage fibers in cow manure, must be separated in a pretreatment
step and kept from the lagoon. If dairy solids are not separated, they will float to the top and
form a crust. The crust will thicken, reducing biogas production and eventually filling the
lagoon.
A complete-mix digester is a biological treatment unit that anaerobically decomposes animal
manures using controlled temperature, constant volume, and mixing. These digesters can
accommodate the widest variety of wastes. Complete-mix digesters are usually aboveground,
heated, insulate^, round tanks; however, the complete-mix design has also been adapted to
function in a heated, mixed, covered earthen basin. Mixing can be accomplished with gas
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recirculation, mechanical propellers, or liquid circulation. In Europe, some mixed digesters are
operated at thermophilic temperatures; however, most of these are regional digesters that are
built and operated by digester professionals. A complete-mix digester can be designed to
maximize biogas production as an energy source or to optimize volatile solids (VS) reduction
with less regard for surplus energy. Either process is part of a manure management system, and
supplemental effluent storage is required.
Plug-flow digesters are heated, unmixed, rectangular tanks. New waste is pumped into one end of
the digester, thereby displacing an equal portion of older material horizontally through the
digester and pushing the oldest material out through the opposite end. Lusk (1998) refers to a
slurry-loop digester as a separate digester category, but this system, which is built in the shape of
a horseshoe, functions by displacement in the same manner as a plug-flow digester.
Biogas formed in a digester bubbles to the surface and may be collected by a fixed rigid top, a
flexible inflatable top, or a floating cover, depending on the type of digester. Biogas from a
stable digester is saturated and contains 60 to 80 percent methane, with the balance as carbon
dioxide and trace amounts of hydrogen sulfide (1,800 to 5,000 ppm H2S). A collection system
directs the virtually odorless biogas to gas handling components. Biogas may be filtered for
mercaptan and moisture removal before being pumped or compressed to operating pressure and
then metered to equipment for use. Biogas that is pressurized and metered can be used as fuel for
heating, adsorption cooling, electrical generation, or cogeneration.
Application and Performance: Properly designed anaerobic lagoons are used to produce biogas
from dilute wastes with less than 2 percent total solids (98 percent moisture), including flushed
dairy manure, dairy parlor washwater, and flushed hog manure. Complete-mix digesters can be
used to decompose animal manures with 3 to 10 percent total solids. Plug-flow digesters are
used to digest thick wastes (11 to 13 percent total solids) from ruminant animals, including dairy
and beef animals. The plug-flow system operates best with scrape-collected, fresh dairy manure
that contains low levels of dirt, gravel, stones, or straw.
Anaerobic digestion is one of the few manure treatment options that reduce the environmental
impact of manure and produce a commodity—energy—that can be used or sold continuously.
Digesters are used to stabilize manures to produce methane, while at the same time reducing
odors.
Approximately 35 percent of the volatile solids from dairy manure and 60 percent of the volatile
solids from swine or beef manure can be converted to biogas and removed from the manure
liquid.
Table 8-11 summarizes the performance expected from anaerobic digesters. Anaerobic digesters
will reduce biological oxygen demand (BOD) and total suspended solids (TSS) by 80 to 90
percent, and virtually eliminates odor. The digester will have minimal effect on the nutrient
content of the digested manure passing through plug-flow or complete^-mix digesters. Half or
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Table 8-11. Anaerobic Unit Process Performance
Digester type
Complete-mix
Plug-flow
Covered first cell of
two-cell lagoon
HRT
(days)
12-20
18-22
30-90
Percentage Reduction
COD
35-70
35-70
70-90
TS
25-50
20-45
75-95
VS
40-70
25-40
80-90
TN
0
0
25-35
P
0
0
50-80
K
0
0
30-50
more of the organic N (Org-N) is converted into ammonia (NHj-N). In lagoons, the
concentrations of nutrients are reduced through settling, volatilization, and precipitation. With a
cover in place, ammonia volatilization losses are eliminated, leaving only settling and
precipitation as pathways for N loss. A small amount of the P and K will settle as sludge hi most
digesters.
The reductions of P, K, or other nonvolatile elements reported hi the literature for covered
lagoons are not really reductions at all. The material settles and accumulates in the lagoon,
awaiting later management. Vanderholm (1975) reported P losses of up to 58 percent. Bortone
et al. (1992) suggest that P accumulation hi anaerobic lagoons may be due to high pH driving
phosphate precipitation as Ca(PO4)2 and Mg(PO4)2. This is consistent with and supported by P-
mass-losses documented hi most lagoon studies. Water-soluble cations, such as sodium,
potassium, and ammonium N, tended to be distributed evenly throughout the lagoon. Humenik
et al. (1972) found that 92 to 93 percent of the copper and zinc hi anaerobic swine lagoon
influent was removed and assumed to be settled and accumulated hi sludge.
Pathogen reduction is greater than 99 percent hi mesophilic and thermophilic digesters with a
20-day HRT. Digesters are also very effective hi reducing weed seeds.
Advantages and Limitations: Some advantages of anaerobic digestion include the opportunity to
reduce energy bills, produce a stabilized manure,, recover a salable digested solid by-product,
reduce odor and fly breeding, and produce a protein-rich feed from the digested slurry.
The energy from biogas can be used on site as a fuel or sold to a local utility company. On-site
uses include the heating of the digester itself, fuel for boilers or electric generators, hot water
production, and refrigeration. The equipment listed m Table 8-12 can use biogas in lieu of
low-pressure natural gas or propane.
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Table 8-12. Biogas Use Options
Electrical generator
Refrigeration compressors
Irrigation pumps
Hot water boiler
Hot air furnace
Direct fire room heater
Adsorption chiller
electricity for use or sale, heat recovery optional
cooling, heat recovery optional
pumping, heat recovery optional
for space heat, hot water for process and cleanup
for space heat
for space heat
for cold water production, heat recovery optional
Dairy waste digesters partially decompose fibrous solids to a uniform particle size that is easily
separated with a mechanical separator. The recovered solids are valuable for reuse as cow
bedding or can be sold as a bagged or wholesale soil product.
Limitations include the costs associated with building and operating the digester. Furthermore,
nutrient concentrations in the semisolid anaerobic digestion product are not reduced substantially
unless they are then stored for several months. Therefore, the amount of land needed for land
application of manure is greater than that needed for uncovered lagoons and other treatment
practices.
Operational Factors: The successful operation of a properly designed digester is dependent
upon two variables: feed rate and temperature. All other operational issues are related to
ancillary equipment maintenance. Once a properly designed digester is operating, it will usually
continue to function unless management oversight is lacking. Reactor capacity is maintained
through periodic removal of settled solids and grit.
A sudden drop in biogas production or pH (from accumulation of organic acids) will indicate
digester upset. Factors that decrease the efficiency of microbial processes and might result in
digester upset include a change in temperature or feed rations, a change in manure loading rates,
or the addition of large quantities of bacterial toxins. A normal ratio of alkalinity to volatile acids
during a stable or steady-state anaerobic decomposition is 10:1. The known operating range is
4:1 to 20:1. (Metcalf and Eddy, 1979). An increase in volatile acids resulting in an alkalinity to
volatile acid ratio of 5:1 indicates the onset of failure of methane-producing anaerobic digestion
(unbalanced decomposition) (Chynoweth, 1998).
The level of hydrogen sulfide in the produced biogas can be controlled through either scrubbing
or managed operation of equipment. Scrubbing is necessary for some gas uses but is generally
expensive and maintenance intensive.
Demonstration Status: Anaerobic lagoons with covers were used at 1.8 percent of
grower/finisher operations in 1995 (USDA APHIS, 1999). Approximately 30 pig lagoons have
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been covered in the United States for odor control or methane recovery (RCM, 1999). The oldest
continuously operating covered swine waste lagoon is at Roy Sharp's Royal Farms in Tulare,
California. This system, which was installed in 1981, has been producing electricity with the
recovered methane since 1983. Not all covered lagoon projects have beneficial uses for
recovered methane; some farms either flare or release the gas.
The oldest complete-mix pig manure digester in the United States was built in 1972.
Approximately 10 units are in operation today, 6 of which were built within the last 4 years.
Many digesters are not operational, typically because the farm is no longer in the pig business.
At least 16 operating plug-flow and slurry-loop digesters are currently operating in the United
States (Lusk, 1998; RCM, 2000).
Practice: Single-Cell Lagoon With Biogas Generation
Description: In this practice, a cover is floated on the surface of a properly sized anaerobic
lagoon to recover biogas (70 percent methane and 30 percent carbon dioxide). Anaerobic
lagoons can produce biogas from any type of animal manure. The most successful arrangement
consists of two lagoons connected in series to separate biological treatment for biogas production
and storage for land application. A variable-volume, one-cell lagoon designed for both treatment
and storage can be covered for biogas recovery; however, a single-cell lagoon cover presents
design challenges due to the varying level of the lagoon surface.
In the early 1960s, the floating cover industry expanded beyond covering water reservoirs into
floating covers for industrial wastewater lagoons. Covering industrial organic wastewater
lagoons began as an odor control technique. Within the discovery mat economic quantities of
biogas could be recovered, cover systems were refined to collect and direct biogas back to the
factory producing the organic waste. Lagoon design was optimized to provide both good
BOD/COD reduction and a supply of usable biogas. Today, hundreds of industrial anaerobic
lagoons have floating covers that optimize anaerobic digestion, control odor, and recover biogas.
The industries that use such covers include pork processors and rendering plants in the United
States. Lessons learned in the development of floating covers are incorporated into today's
designs for animal waste facilities.
Psychrophilic, or low-temperature, digestion is the natural decomposition path for manures at the
temperatures found in lagoons. These temperatures vary from about 38 to 85 °F (3 to 29 °C).
The retention time required for stable operation varies from 120 days at low temperatures to 30
days at the higher temperatures. Methane production varies seasonally with lagoon temperature.
More methane is produced from warmer lagoons than from colder lagoons.
The Natural Resources Conservation Service (1998) developed NRCS Interim Practice Standard
360, Covered Anaerobic Lagoon, to guide floating cover design, installation, and operation.
Many types of materials have, been used to cover agricultural lagoons. Floating covers are not
limited in dimension. A floating cover allows for some gas storage. Cover materials must have
a bulk density near that of water and must be UV-resistant, hydrophobic, tear- and puncture-
resistant, and nontoxic to aquatic aerobes and anaerobes.
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Several types of material are used to construct floating covers, including high-density
polyethylene, XR-5, polypropylene, and hypalon. Material is selected based on material
properties (such as UV resistance), price, availability, installation, and service. Installation teams
with appropriate equipment travel and install covers.
Biogas formed in a digester bubbles to the surface and is collected and directed by the cover to a
gas use. Biogas from a stable covered lagoon is virtually odorless and saturated. It contains 70
to 85 percent methane; the balance is carbon dioxide and trace amounts of hydrogen sulfide
(1,000 to 3,000 ppm H2S). Biogas can be harmful if inhaled directly, corrosive to equipment, and
potentially explosive in a confined space when mixed with air. When properly managed, the
off-gas is as safe as any other fuel (e.g., propane) used on the farm. Safety concerns are more
completely addressed in the Handbook of Biogas Utilization (Ross, 1996).
Biogas may be filtered for mercaptan and moisture removal. Biogas is usually pumped, or
compressed to operating pressure and then metered to the gas use equipment. Biogas can be used
as fuel for heating, electrical generation, or cogeheration. Alternatively, it can simply be flared
for odor control.
Application and Performance: Covered lagoons are used to recover biogas and control. Covers
can be installed to completely cover the lagoon and capture clean rainwater. The uncontammated
rainwater can be safely pumped off, reducing the volume of lagoon liquid to be managed later.
Off-gases collected by an impermeable cover on an anaerobic manure facility are neither
explosive nor combustible until mixed with air in proper proportions to support combustion. No
reports of any explosions of biogas systems at animal production facilities were found.
Table 8-13 summarizes the performance expected from covered lagoons. Anaerobic digestion in
a covered lagoon will reduce BOD and TSS by 80 to 90 percent Odor is virtually eliminated.
The concentrations of nutrients are reduced through settling and precipitation in lagoons.
Ammonia volatilization losses are virtually eliminated with a cover in place, leaving only settling
and precipitation as pathways for N loss.
During anaerobic digestion, microbial activity converts half or more of the organic N (Org-N) to
soluble ammonia (NH3-N). Cheng (1999) found that 30 percent of the total Kjeldahl N (TKN,
which includes ammonia and organic N) entering the covered first cell of a two-cell lagoon was
retained in that cell, probably as organic N in slowly degradable organics in the sludge. A similar
loss due to settling could be expected in a covered single-cell lagoon. A covered single-cell
lagoon will not lose NH3-N to the atmosphere; however NH3-N will be volatilized from the
uncovered second cell of a two-cell lagoon. Cheng (1999) also reported that approximately 50
percent of the influent TKN was subsequently lost from the uncovered second cell of the system.
Reported reductions of P, K,.or other nonvolatile elements through a covered lagoon are not
really reductions at all. The material settles and accumulates in the lagoon awaiting later
management. This is consistent with and supported by P mass losses documented in most lagoon
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studies Humenik et al. (1972) found that 92 to 93 percent of the copper and zinc in anaerobic
swine lagoon influent was removed and assumed to be settled and accumulated in sludge. .
Table 8-13. Anaerobic Unit Process Performance
Digester type
Covered lagoon
HRT
Days
30-90
Percentage Reduction
COD
70-90
TS
75-95
VS
80-90
Source: Moser, 1999.
TN
25-35
P
50-80
K
30-50
Cheng (1999) found pathogen reduction through a North Carolina covered lagoon to be 2 to 3
orders of magnitude. J. Martin (1 999) determined that relationships between temperature and
the time required for a one loglo reduction in densities of pathogens were consistently exponential
m form. Although there is substantial variation between organisms regarding the time required
tor a one logIO reduction in density at ambient temperatures, this work suggests that variation in
die-off rates among species decreases markedly as temperature increases. For example the
predicted time required for a one loglo reduction in fecal streptococcus density decreases from
63 7 days at 15 C to 0.2 day at 50 °C. For S. aureus, the decrease is from 10.6 days at 15 °C to
U. l;day at 50 C. -Thus, for-both storage and treatment at ambient temperature, an extended
period of time is predicted for any significant reduction. A single-cell covered lagoon has a •
longer residence time than the covered first cell of a two-cell lagoon and should therefore have a
greater reduction of pathogens. However, duringpumpout of a single-cell lagoon, fresh influent
can be short-circuited to the pumpout, carrying pathogens with it, whereasthe covered first cell
of a two-cell lagoon produces a consistent pathogen reduction without short-circuiting because
wT* S Path°gen destr°ying retention time is not affected when the second cell is pumped
Advantages and Limitations: The advantages of covered anaerobic lagoons are the reduction of
lagoon odor, exclusion of rainfall from the lagoon, recovery of usable energy, reduction of
ammonia volatilization, and reduction of methane emissions. There are also significant labor
savings involved in handling manure as a liquid and being able to apply lagoon waters to the land
through irrigation. Solids are broken down through microbial activity, and organic matter is
stabilized when anaerobic digestion is complete, reducing the potential for production of noxious
by-products. A bank-anchored cover prevents the growth of weeds where the cover is placed
Finally, treated lagoon water can be recycled for flush water in confinement houses, resulting in
cost savings in areas where water is scarce.
Limitations of covered anaerobic lagoons include the cost of installing a cover, which in 1999
varied from $0.37 to $1.65 per square foot (Martin, 1999), and the occasional need for cover
maintenance such as rip repair, and rainfall pump-off. The lagoons themselves can be large
depending on the size of the hog operation, and can require a significant amount of cover
material. Spills and leaks to surface and ground water can occur if the lagoon capacity is
exceeded, or if structural damage occurs to berms, seals, or liners. The treatment capacity of
most lagoons is diminished by sludge accumulation, and sludge has to be removed and managed.
8-75 '
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Operational Factors: Lagoons should be located on sorts of low permeability or soils that seal
through biological action or sedimentation, and proper liners should be used to avoid
contamination of ground water. Proper sizing and management are necessary to effectively
operate a covered anaerobic lagoon and maintain biogas production. The niinimum covered
lagoon capacity should include treatment volume, sludge storage, freeboard, and, if necessary,
storage for seasonal rainfall and a 25-year, 24-hour rainfall event.
Temperature is a key factor in planning the treatment capacity of a covered lagoon. The lagoons
are not heated, and the lagoon temperature and biogas production vary with ambient
temperatures. Warm climates require smaller lagoons and have less variation in seasonal gas
production. Colder temperatures will reduce whiter methane production. To compensate for
reduced temperatures, loading rates are decreased and hydraulic retention time is increased. A
larger lagoon requires a larger, more costly cover than a smaller lagoon in a warmer climate.
The floating cover must be designed and operated in such a way as to keep it from billowing in
windy conditions. Coarse solids, such as hay and silage fibers in cow manure, must be separated
in a pretreatment step and kept from the lagoon. If dairy solids are not separated, they float and
form a crust The crust will thicken, reducing biogas production and eventually filling the
lagoon.
Proper lagoon inspection and maintenance are necessary to ensure that lagoon liners and covers
are not harmed by agitating and pumping, berms and embankments are stable, and the required
freeboard and rainfall storage are provided. Sampling and analysis of the lagoon water are
suggested to determine its nutrient content and appropriate land application rates.
Anaerobic lagoons accumulate sludge over time, diminishing treatment capacity. Lagoons must
be cleaned out once every 5 to 15 years, and the sludge can be applied to land other than the
spray fields receiving the lagoon liquid. Because crop P requirements are less than those for N, it
takes more land to apply the sludge from lagoon cleanout than to apply liquid wastewater.
Demonstration Status: Floating-cover technology is well developed and readily available.
Covering lagoons for odor control has been demonstrated in all sectors of the animal production
industry. The installation of floating covers specifically for methane recoveiy is a less common,
but well-known practice. There are at least 10 covered lagoon systems with biogas collection
and combustion in the pig and dairy industries (Lusk, 1998; RCM, 2000).
Practice: Aerobic Treatment of Liquids , ,
Description: Conventional aerobic digestion is a process used frequently at small municipal and
industrial wastewater treatment plants for biosolids stabilization. It is a suspended growth
process operating at ambient temperature in the stationary or endogenous respiration phase of the
microbial growth curve. In the stationary phase, the exogenous supply of energy is inadequate to
support any net microbial growth. Endogenous respiration occurs when the exogenous supply of
energy also is inadequate to satisfy cell maintenance requirements, and a net decrease in
microbial mass occurs. Operating parameters include a relatively long period of aeration,
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ranging from severa daysl to more than 30 days, depending on the degree of stabilization desired
Given the relatively long period of aeration, activated sludge recycling is not necessary and
hydrate detention and solids retention times are equal in continuous-flow systems. This is a
major difference between aerobic digestion and the various variants of the activated sludge
process, including extended aeration (see "Secondary Biological Treatment" below) When
aerobic digestion is used for biosolids stabilization, either the fill-and-draw or the continuous
mode of operation can be used. With the fill-and-draw mode of operation, an option is to
periodically cease aeration temporarily to allow settling and then decant the clarified liquid
before resuming aeration. This approach also allows the reactor to be used as a biosolids
thickener.
With conventional aerobic digestion, substantial reductions in total and volatile solids
biochemical and chemical oxygen demand, and organic N can be realized. Total N reduction can
also be substantial, with either ammonia stripping or nitrification-denitrification serving as the
primary mechanism, depending on the dissolved oxygen concentration of the mixed liquor
Actual process performance depends on a number of variables, including solids retention time
temperature, and adequacy of oxygen transfer and mixing.
An aeration basin typically is used for the aerobic digestion of municipal and industrial
wastewater biosolids. In contrast, several reactor types, including oxidation ditches and
mechanically aerated lagoons, as well as aeration basins, have been used for the aerobic digestion
of animal manures. Under commercial conditions, the oxidation ditch has been the most
commonly used because it can be located in the animal housing unit under cages for laying hens
or under slatted floors for swine. .This eliminates the need for transport of manure to the
treatment system.
It should be noted that since the oxidation ditch was originally developed to employ the activated
sludge process used in municipal wastewater treatment, the term "activated sludge" has been
used incorrectly on occasion to describe the aerobic digestion of swine, poultry, and other animal
wastes. Aerobic digestion, not the activated sludge process, is employed in oxidation ditches
mechanically aerated lagoons, and aeration basins. Table 8-14 presents technologies that use'
aerobic digestion or the activated sludge process.
Application and Performance: Conventional aerobic digestion is an option for all swine and
poultry operations where manure is handled as a liquid or slurry, and it can be used with flushing
systems using either mixed liquor or clarified effluent as flush water. With proper process design
and operation, a 75 to 85 percent reduction in 5-day biochemical oxygen demand (BODS) appears
achievable, with a concurrent 45 to 55 percent reduction in chemical oxygen demand (COD) and
a 20 to 40 percent reduction in total solids (TS) (Martin, 1999). In addition, a 70 to 80 percent
reduction of the N in both poultry and swine wastes via nitrification-denitrification also appears
possible. Total P is not reduced, but the soluble fraction may increase. As with aerobic digestion
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Table 8-14. Operational Characteristics of Aerobic
Digestion and Activated Sludge Processes
Process
Modification
Conventional
Complete mix
Step feed
Modified
aeration
Contact
stabilization
Extended
aeration
High-rate
aeration
Kraus process
High-purity
oxygen
Oxidation ditch
Sequencing
batch reactor
Deep-shaft
reactor
Single-stage
nitrification
Separate stage
nitrification
Flow Model
Plug flow
Continuous-flow
stirred-tank
reactor
Plug flow
Plug flow
Plug flow
Plug flow
Continuous-flow
stirred-tank
reactor
Plug flow ,
Continuous-flow
stirred-tank
reactors in series
Plug flow
Intermittent-flow
stirred-tank
reactor
Plug flow
Continuous-flow
stirred-tank
reactors or plug
flow
Continuous-flow
stirred-tank
reactors or plug
flow
Aeration System
Diffused-air,
mechanical aerators
Diffused-air,
mechanical aerators
Diffused air
Diffused air.
Diffused-air,
mechanical aerators
Diffused-air,
mechanical aerators
Mechanical aerators
Diffusedair-
Mechanical aerators
(sparger turbines)
Mechanical aerators
(horizontal axis type)
Diffused air
Diffused air
Mechanical aerators,
diffused-air
Mechanical aerators,
diffused-air
BOD
Removal
Efficiency
(percent)
85-95
85-95
85-95
60-75
80-90
75-95
... 75-90
. . 85-95 ...... .
85-95
75-95
85-95
85-95
85-95
85-95
Remarks '
Use for low-strength domestic wastes.
. Process is susceptible to shock loads.
Use for general application. Process is
resistant to shock loads, but is
susceptible to filamentous growths.
Use for general application for a wide
range of wastes.
Use for intermediate degree of
treatment where cell tissue in the
effluent is not objectionable.
Use for expansion of existing systems
and package plants.
Use for small communities, package
plants, and where nitrified element is
required. Process is flexible.
Use for general applications .with
turbine aerators to transfer oxygen and
control floe size.
. Use for low-N, high-strength wastes.
Use for general application with high-
strength waste and where on-site space
is limited. Process is resistant to slug
loads.
Use for small communities or where
large area of land is available. Process
is flexible.
Use for small communities where land
is limited. Process is flexible and can
remove N and P.
Use for general application with high-
strength wastes. Process is resistant to
slug loads.
Use for general application for N
control where inhibitory industrial
wastes are not present.
Use for upgrading existing systems,
where N standards are stringent, or
where inhibitory industrial wastes are
present and can be removed in earlier
stages.
Source: Metcalf and Eddy, 1991.
.8-78
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of biosolids, some reduction in' pathogen densities may also occur depending on process
temperature.
Advantages and Limitations: In addition to the potential for substantial reductions hi oxygen-
demanding organics and N, one of the principal advantages of aerobic digestion of poultry and
swine manures is the potential for a high degree of odor control. Another advantage is the
elimination of fly and other vermin problems.
Limitations include high energy requirements for aeration and mixing (e.g., pumps, blowers, or
mixers for mechanical aeration). In addition, aerobic lagoons without mechanical aeration are
generally shallow, requiring a very large land area to meet oxygen demands. The absence of a
reduction in the volume of waste requiring ultimate disposal is another limitation. In certain
situations, waste volume will be increased significantly. For example, use of an undercage
oxidation ditch versus a high-rise type system to manage the waste from laying hens will increase
substantially the waste volume requiring ultimate disposal. Also, management, maintenance and
repair requirements for aerobic digestion systems can be significant. For example, liquids and
solids must be separated in a pretreatment step when aerated lagoons are used. .
Operational Factors: Establishing and maintaining an adequate microbial population in aerobic
digestion reactors is critical to ensure optimal process performance. Failure to do so will lead to
excessive foam production, which has suffocated of animals on slatted floors above in-building
oxidation ditches. Failure to remove slowly biodegradable solids on a regular basis to maintain a
mixed liquor total solids concentration of about 1 percent in fill-and-draw systems will lead to a
substantial reduction in oxygen transfer efficiency and mixing. This results in reduced treatment
efficiency and the potential for generation of noxious odors and release of poisonous gases,
particularly hydrogen sulfide. Because ambient temperature determines process temperature,
seasonal variation in process performance occurs.
Demonstration Status: Aerobic digestion has not been adapted to any significant degree by the
poultry, dairy, or swine industries, although a number of research and demonstration scale studies
were conducted in the late 1960s and early 1970s. Problems related to process and facilities
design, together with the significant increase hi electricity costs in the early to mid-1970s, led to
a loss of interest in this animal waste treatment alternative. It is possible that no aerobic '
digestion systems for annual wastes are currently in operation in the poultry and swine industries.
Lagoons are the most popular method of treatment for livestock manure. Aerobic lagoons are
commonly used for secondary treatment and storage of anaerobic lagoon wastes. Despite the
advantages, however, aerobic lagoons are considered uneconomical for livestock manure
treatment.
Practice: Autoheated Aerobic Digestion
Description: Autoheated aerobic digestion uses heat released during the microbial oxidation of
organic matter to raise process temperature above ambient levels. This is accomplished by
minimizing both sensible and evaporative heat losses through the use of insulated reactors and
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aeration systems with high-efficiency oxygen transfer. Mesophilic temperatures, 86 °F (30 °C) or
higher, typically can be maintained even in cold climates, and thermophilic temperatures as high
as 131 to 149 °F (55 to 65 °C) can be attained. Both ammonia stripping and
mtrification-demtrification can be mechanisms of N loss at mesophilic temperatures;
nitrification-denitrification is typically the principal mechanism if the aeration rate is adequate to
support nitrification. Because both Nitrosomas and Nitrobacter, the bacteria that convert
ammonium ions into nitrate, are mesophiles, N loss at thermophilic temperatures is limited to
ammonia stripping. Typically, autoheated digestion reactors are operated as draw-and-fill
reactors to minimise influent short-circuiting, especially when maximizing pathogen reduction is
a treatment objective. •
Application and Performance: Autoheated aerobic digestion is appropriate for all livestock and
poultry operations where manure is handled as a slurry that has a niinimum total solids
concentration of at least 1 to 2 percent, wet basis. At lower influent total solids concentrations,
such as those characteristic of flushing systems, achieving process temperatures significantly
above ambient levels is problematic because of an insufficient biological heat production
potential relative to sensible and evaporative heat losses. As influent total solids concentration
increases, the potential for achieving thermophilic temperatures also increases. Influent total
solids concentrations of between 3 and 5 percent are necessary to attain thermophilic
temperatures. ,
With proper process design and operation, the previously discussed reductions in biochemical
oxygen demand (BODS), chemical oxygen demand, total solids, and total N that can be realized
with conventional aerobic digestion also can be realized with autoheated aerobic digestion
(Martin, 1999a). Autoheated aerobic digestion can also provide significant reductions in
pathogen densitiesTn a relatively short 1- to 2-day period of treatment. Reductions realized are a
function of process temperature. At a process temperature of 122 °F (50 °C) or greater, a
minimum of at least a one Iog10 reduction in the density of most pathogens is highly probable,
with two to three Iog10 reductions likely (Martin, 1999b).
Advantages and Limitations: With respect to waste stabilization and odor control, the potential
benefits of conventional and autoheated aerobic digestion are comparable. The principal
advantages of autoheated aerobic digestion relative to conventional aerobic digestion from a
process performance perspective are (1) higher reaction rates that translate into shorter detention
times to attain a given degree of stabilization and (2) more rapid reduction in densities of
pathogens. The time required to achieve comparable reductions in BOD5, chemical oxygen
demand, total solids, and total N is much shorter in autoheated than hi conventional aerobic
digestion. With autoheated aerobic digestion, these reductions occur within 1 to 3 days at
thermophilic temperatures, whereas 15 days or more are required with conventional aerobic
digestion at ambient temperatures. This translates directly into smaller reactor volume
requirements.
The ability to provide rapid and substantial (at least a one Iog10) reductions in pathogen densities
is one of the more attractive characteristics of autoheated aerobic digestion. This ability has been
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demonstrated in several" studies of autoheated aerobic digestion of biosolids from municipal
wastewater treatment, including a study by Martin et al. (1990).
The high energy requirements for aeration and mixing are limitations of autoheated aerobic
digestion. In addition, waste volume is not reduced through the treatment process. However, the
requirement of a less dilute influent waste stream, as compared with conventional aerobic
digestion, for example, to provide the necessary biological heat production potential translates
into reduced ultimate disposal requirements.
Operational Factors: A foam layer covering the mixed liquor in autoheated aerobic digestion
reactors is a common characteristic and serves to reduce both sensible and evaporative heat
losses. It is.necessary, to control the depth of this foam layer to ensure that an overflow of foam
from the reactor does not occur. Typically, mechanical foam cutters are used. Although
autoheated aerobic digestion is less sensitive to fluctuations in ambient temperature than are
other treatment processes, such as conventional aerobic digestion, some reduction in treatment
efficiency can occur, especially during extended periods of extremely cold weather.
Demonstration-Status: The feasibility of using autoheated aerobic digestion to stabilize swine
manure has been demonstrated in several studies (Martin, 1999b). Feasibility also has been
demonstrated in several studies with cattle manure, including studies by Terwilliger and Crauer
(1975) and Cummings and Jewell (1977); however, there does not appear to have been any
comparable demonstration of feasibility with poultry wastes. Given the similarities in the
composition of swine and poultry wastes, it is highly probable that autoheated aerobic digestion
of poultry wastes is also technically feasible. Although no data are available, it is probable, that
this waste treatment technology is not currently being used in any segment of animal agriculture,
primarily because of the associated energy cost.
Practice: Secondary Biological Treatment
Description: The activated sludge process is a widely used technology for treating wastewater
that has high organic content. The process was first used in the early 1900s and has since gained
popularity for treatment of municipal and industrial wastewater. Many versions of this process
are in use today, but the fundamental principles are similar. Basically, the activated sludge
process treats organic wastes by maintaining an activated mass of microorganisms that
aerobically decomposes and stabilizes the waste.
Primary clarification or solids settling is the first step hi the activated sludge process. Next, the
organic waste is introduced into a reactor. Maintained in suspension in the reactor is a biological
culture that converts the waste through oxidation and synthesis. The aerobic environment in the
reactor is achieved using diffused or mechanical aeration, which also maintains a completely
mixed state. After a specified period, known as the hydraulic retention time (HRT), the mixture
in the reactor is passed to a settling tank. A portion of the solids from the settling tank is
recycled to the reactor to maintain a balance of microorganisms. Periodically, solids from the
settling tank are "wasted" or discharged to maintain a specific concentration of microorganisms
in the system. The solids are discharged according to a calculated solids retention time (SRT),
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which is based on the influent'characteristics and the desired effluent quality. The overflow from
the settling tank is discharged from the system.
Application and Performance: The activated sludge process is very flexible and can be used to
treat almost any type of biological waste. It can be adapted to provide high levels of treatment
under a wide range of operating conditions. Properly designed, installed, and operated activated
sludge systems can reduce the potential pollution impact of feedlot waste because this technology
has been shown to reduce carbon-, N-, and P-rich compounds.
In the activated sludge process, N is treated biologically through nitrification-denitrification. The
supply of air facilitates nitrification, which is the oxidation of ammonia to nitrite and then nitrate.
Denitrification takes place in an anoxic environment, in which the bacteria reduce the nitrate to
nitrogen gas (Nj), which is released into the atmosphere. The activated sludge process can nitrify
and denitrify in single- and double-stage systems.
Phosphorus is removed biologically when an anaerobic zone is followed-by an aerobic zone,
causing the microorganisms to absorb P at an above-normal rate. The activated sludge
technology most effective for removing P is the sequencing batch reactor (see "Sequencing Batch
Reactors," below).
N and P can both be removed in the same system. The SBR is also most effective for targeting
removal of both N and P because of its ability to alternate aerobic and anaerobic conditions to
control precisely the level of treatment.
Advantages and Limitations: An advantage of the activated sludge process is that it removes
pollutants, particularly nutrients, from the liquid portion of the waste. Nutrient removal can
allow more feedlot wastewater to be applied to land without overloading it with N and P.
Furthermore, concentrating the nutrients in a sludge portion can potentially reduce transportation
volumes and costs of shipping excess waste.
A disadvantage of an activated sludge system compared with an anaerobic lagoon is the relatively
high capital and operating costs and the complexity of the control system. In addition, because
pollutants will remain in the sludge, stabilization and pathogen reduction are necessary before
disposing of it.
Because the activated sludge process does not reduce pathogens sufficiently, another way to
reduce pathogens in both the liquid and solid portions of a waste may be appropriate prior to
discharge or land application. The liquid effluent from an activated sludge system can be
disinfected by using chlorination, ultraviolet radiation, or ozonation, which are the final steps in
many municipal treatment systems. • .
Operational Factors: Many.parameters can affect the performance of an activated sludge
system. Organic loading must be monitored carefully to ensure that the microorganisms can. be
sustained in proper concentrations to produce a desired effluent quality. The principal factors hi
the control of the activated sludge process are:
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• Maintaining dissolved oxygen levels in the aeration tank (reactor);
Regulating the amount of recycled activated sludge from the settling tank to the
reactor; and
• Controlling the waste-activated sludge concentration in the reactor.
Ambient temperature can also affect treatment efficiency of an activated sludge system.
Temperature influences the metabolic activities of the microbial population, gas-transfer rates,
and settling characteristics of biological solids. In cold climates, a larger reactor volume may be
necessary to achieve treatment goals because nitrification rates decrease significantly at lower
temperatures.
Demonstration Status: Although activated sludge technologies have not been demonstrated on a
full-scale basis in the animal feedlot industry, the process may treat such waste effectively.
Studies have been performed on dairy and swine waste to determine the level of treatment
achievable in an SBR (see "Sequencing Batch Reactors," below). The SBR is simpler, more
flexible, and perhaps more cost-effective than other activated sludge options for use in the
feedlots industry.
Practice: Sequencing Batch Reactors
Description: A sequencing batch reactor (SBR) is an activated sludge-treatment-system in which
the processes are carried out sequentially in the same tank (reactor). The SBR system may
consist of one reactor, or more than one reactor operated in parallel. The activated sludge
process treats organic wastes by maintaining an aerobic bacterial culture, which decomposes and
stabilizes the waste. An SBR has five basic phases of operation, which are described below.
Fill Phase: During me fill phase, influent enters the reactor and mechanical mixing begins. The
mixing action resuspends the settled biomass from the bottom of the reactor, creating a
completely mixed condition and an anoxic environment. As wastewater continues entering the
reactor, oxygen may also be delivered, converting the environment from anoxic to aerobic.
Depending on the desired effluent quality, the oxygen supply can be operated in an "on/off'
cycle, thus alternating the aerobic and anoxic conditions and accomplishing nitrification and
denitrification.
React Phase: During the react phase, wastewater no longer enters the reactor. Influent to the
system is instead either stored for later treatment in a single-reactor system or diverted to another
reactor to begin treatment in a system with multiple reactors. Mechanical mixing continues
throughout this phase. The oxygen supply may be operated in a cyclical manner, as described in
the fill phase, to accomplish additional denitrification if necessary. Activated sludge systems,
such as SBRs, depend upon developing and sustaining a mixed culture of bacteria and other '
microbes (i.e., the biomass) to accomplish the treatment objectives.
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Settle Phase: During the settle phase, the oxygen supply system and mechanical mixer do not
operate, This phase provides a quiescent environment in the reactor and allows gravity solids
separation to occur, much like in a conventional clarifier.
Draw Phase: Following the treatment of a batch, it is necessary to remove from the reactor the
same volume of water that was added during the fill phase. After a sufficient settling phase, the
liquid near the top of the reactor is decanted to a predetermined level and discharged or recycled.
Idle Phase: The idle phase is a time period between batches during which the system does not
operate. The duration of this unnecessary phase depends on the hydraulic aspects of the reactor.
However, as a result of biological degradation and accumulation of inert materials from the
wastewater, solids must be discharged from the reactor periodically to maintain a desirable level
of mixed liquor suspended solids. This "sludge wasting" is done during the idle phase, or
immediately following the draw phase.
Application and Performance: SBR technology could be applied to reduce the potential
pollution impact of liquid manure waste from dairies because this technology has been shown to
reduce carbon-, N-, and P-rich compounds. Removing these pollutants from the liquid portion of
the waste could allow for greater hydraulic application to lands without exceeding crop nutrient
needs. Concentrating the nutrients in the sludge portion could potentially reduce transportation
volumes and cost of shipping excess waste. Although a proven technology for treatment of
nutrients in municipal wastewater, available data does not exist showing SBRs to be effective in
pathogen reduction.
Given the processes it employs, SBR treatment may allow treated dairy wastewater to be either
applied to land or discharged to a stream if a sufficient level of treatment can be achieved.
Further, Ihe sludge from the wasting procedure could be applied to land, composted, or sent off
site for disposal. Aqua-Aerobic Systems of Rockford, Illinois, (Aqua-Aerobics, 2000) estimates
a sludge production rate of approximately 1.3 pounds of waste activated sludge per pound of
BODS entering the system. The use of SBRs to treat dairy waste has been studied in the
laboratory at both Cornell University and the University of California at Davis. Both studies
have shown SBR technology to be effective in reducing pollutants in the liquid portion of dairy
waste, although neither report included specific information on sludge characteristics or P
removals (Johnson and Montemagno, 1999; Zhang et al., 1999).
In the Cornell study, diluted dairy manure was treated in bench-scale reactors (Johnson and
Montemagno, 1999). Experiments were conducted to determine the operating strategy best
suited for the diluted dairy manure. The study resulted in removals of 98 percent of ammonia
(NH3), 95 percent of chemical oxygen demand (COD), 40 percent of nitrate/nitrite (NO3/NO2),
and 91 percent of inorganic N.
The University of California .at Davis studied how SBR performance was affected by hydraulic
retention time (HRT), solids retention time (SRT), organic loading, and influent characteristics of
dairy wastewater (Zhang et al., 1999). The highest removal efficiencies from the liquid portion
of the waste were for an influent COD concentration of 20,000 milligrams per liter (a COD
8-84
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concentration of 10,000 mg/L was also studied) and an HRT of 3 days (HRTs of 1 to 3 days were
studied). With these parameters, laboratory personnel observed removal efficiencies of 85.1
percent for NH3 and 86.7 percent for COD. >
In addition, studies on SBR treatment of swine waste in Canada and of veal waste in Europehave
demonstrated high removal rates of COD, N, and P (Reeves, 1999).
Advantages and Limitations: Technology currently used at dairies includes solids settling basins
followed by treatment and storage of waste in an anaerobic lagoon. Lagoon effluent and solids
are applied to cropland in accordance with their nutrient content, and excess water or solids are
then transported off site. The SBR could replace treatment in an anaerobic lagoon, but there
would still be, a need for solids separation in advance of SBR treatment, as well as a pond or tank
to equalize the wastewater flow. In fact, Aqua-Aerobics (2000) has indicated that solids removal
and dilution of the raw slurry would be necessary to make treatment in the SBR. Following the
SBR, it is possible that some type of effluent storage would be required for periods when direct
irrigation is not possible or necessary.
Use of an SBR is expected to be advantageous at dairies that apply a portion of their waste to
land. The reduced level of nutrients in the liquid portion would allow for application of a greater
volume of liquid waste, thereby reducing the volume of waste that must be transported off site
and possibly eliminating liquid waste transport. An SBR is also beneficial in the handling of the
solids portion of the waste because no periodic dredging is required as is the case with anaerobic
lagoons. Disadvantages of an SBR system are the relatively high capital and operating costs, as-
well as the need to manage the nutrients that remainjn the sludge.
Because the activated sludge process is not a generally accepted method of pathogen reduction,
another means of reducing pathogens in both the liquid and solid portions of the dairy waste may
be appropriate. Disinfection of the liquid effluent from the SBR could be accomplished through
use of chlorination, ultraviolet radiation, or ozonation which are used as the final step in many
municipal treatment systems. Composting has also been demonstrated as a means of reducing
pathogens in organic solid waste and could be implemented for use with the SBR sludge.
Operational Factors: The five phases of SBR operation may be used in a variety of combinations
in order to optimize treatment to address specific influent characteristics and effluent goals. N in
the activated sludge process is treated biologically through the nitrification-denitrification
process. The mtrification-denitrification process in the SBR is controlled through the timing and
cyclical pattern of aeration during the react phase. The supply of air causes nitrification, which is
the oxidation of ammonia to nitrite and then nitrate. To accomplish denitrification, the air supply
is shut off, creating an anoxic environment in which the bacteria ultimately reduce the nitrate to
nitrogen gas (N2), which is released to the atmosphere. The cycle can be repeated to achieve
additional levels of denitrification. Some portion of the N in the influent to the SBR may also
volatilize prior to treatment, and a portion may also be taken up by microorganisms that are
present in the waste activated sludge (Zhang et al., 1999).
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P is removed when an anaerobic zone (or phase) is followed by an aerobic zone, causing the
microorganisms to take up P at an above-normal rate. The waste activated sludge containing the
microorganisms is periodically "wasted" as described above. As such, the bulk of the P will be
concentrated ultimately in the sludge portion with a minimal amount remaining in the liquid
effluent.
N and P can both be removed in the same system. This dual removal is accomplished by
beginning the fill phase without aeration, which creates an anoxic condition allowing for some
denitrification as well as release of P from the cell mass to the liquid medium, there follows a
period of aerated mixing, which will continue into the react phase, allowing for nitrification and
uptake of P. The settle phase, in which no aeration occurs, is extended sufficiently to allow for
additional denitrification. Again, these phases can be repeated or executed for varying durations
in order to accomplish specific treatment goals.
Demonstration Status: Although the SBR technology has not been demonstrated on a full-scale
basis in the dairy industry, SBRs are currently being evaluated for use at dairies because they
generate a high volume of wastewater. Dairy wastewater treated in the SBR includes a
combination of parlor and bam flush/hose water and runoff.
Cornell University is currently studying two pilot-scale SBR systems to further investigate the
treatabiliry of dairy waste (Johnson and Montemagno, 1999). No results from the pilot-scale
study are yet available, although preliminary results for nutrient removal have been favorable and
a full-scale system is being planned.
Practice: Solids Buildup in the Covered First Cell of a Two-Cell Lagoon
Description: This section addresses sludge accumulation, removal, and management in the first
cell of a two-cell lagoon. The first cell may or may not be covered for methane recovery. Some
sludge will be carried from the first cell to the second cell; however, the quantity is not
significant compared with potential accumulations in the first cell. No quantitative information
was found regarding the differences in the rate of accumulation of sludge in the first cell versus
accumulation in a single-cell lagoon. The removal and management of sludge from the first cell
of a two-cell lagoon will be the same as described for sludge cleaning from a single cell lagoon.
For the purpose of this section, sludge is material settled on the bottom of a lagoon receiving
waste from any animal; it has a total solids content greater than 10 percent, generally has a high
angle of repose when dewatered, and will not readily flow to a pump. Sludge includes organic
material not decomposed by lagoon bacteria, and inorganic material such as sand and
precipitates. Sludge accumulation can eventually fill a lagoon.
Accumulated sludge is removed to restore lagoon treatment and storage capacities. Two general
methods of sludge removal, slurry and solid, are described below. When managed as a slurry,
sludge is resuspended with agitation and pumped to tankers or irrigation guns for land
application. Slurry management is desirable when the sludge mixture can be pumped to an
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irrigation gun or hauled a short distance. Sludge removed from covered lagoons is removed as a
slurry.
Sludge managed as a solid is excavated from the lagoon or pumped from the bottom as slurry to
a drying area. Solid sludge is cheaper to haul than slurry because water, which increases the
weight and volume, is not added. Solid sludge can be spread with conventional manure
spreaders or dumped on fields and spread out and disced into the soil. In drier areas of the
country, a lagoon may be withdrawn from service as a parallel lagoon is restored to service. The
lagoon liquids are pumped off to field application and the sludge is allowed to dry. After 4 to 12
months, excavators, backhoes or bulldozers scrape, push, pull, or lift the material into trucks or
wagons for hauling and spreading. Some lagoons are designed to be desludged by dragline
bucket excavators while still in operation. Draglines work along the banks of these long, narrow
lagoons, excavating sludge and either dropping it into trucks for hauling or depositing it on the
lagoon embankment to dry for later hauling.
Application and Performance: Lagoon cleanout is applicable to all two-cell lagoons, regardless
of location. Reported reductions of P, K, and other nonvolatile elements through a lagoon are
not really reductions at all because these materials settle. Nitrogen is considered volatile in the
ammonia form, but some organic N associated with heavier and nondegradable organics also
settles into the lagoon sludge and stays, resulting in a high-organic N fraction of total Kjeldahl N-
(TKN) in settled solids. The settled materials accumulate in the lagoon awaiting later disposal.
Compared with lagoon liquids, lagoon sludges have higher concentrations of all pollutants that
are not completely soluble. All reported data suggest that the sludge is more stable than raw
manure based on its reduced volatile solids/total solids ratio (VS/TS). Volatile solids are a
portion of the total solids that can be biologically destroyed, and as they are destroyed the VS/TS
ratio declines.
As anaerobic digestion of manure changes the solution chemistry in a lagoon, materials such as
ammonia and P form precipitates with Ca and Mg. Fulhage and Hoehne (1999) and Bicudo et al.
(1999) both report concentrations of Ca, Mg, P, and K in lagoon sludge at 10 to 30 times that
found in raw manure. Fulhage and Hoehne also reported that Cu and Zn settle and concentrate to
40 to 100 times the concentration found in lagoon liquid.
Martin (1999), in a review and analysis of factors affecting pathogen destruction, found that time
and temperature controlled the die-off rate of pathogens. Sludge that has been in a lagoon for 10
years is expected to have very low concentrations of pathogens, and those would be associated
with the most recent 90 to 180 days of settling.
Advantages and Limitations: The advantage of lagoon cleanout is that removal of sludge
restores the volume of a first-cell lagoon that is necessary for design treatment capacity. One of
the limitations is that sludge disposal is ignored in most nutrient management plans. Sludge is a
concentrated, nutrient-rich material. The nutrients in the sludge, if applied to the same cropland
historically receiving lagoon liquids, could easily exceed the planned application rate of
nutrients. Phosphorus and other relatively insoluble nutrients are more concentrated than N in
sludge and become the basis of planning proper use of the sludge.
. 8-87
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Ideally, sludge will be managed as a high-value fertilizer in the year it is applied. As the sludge
has a higher nutrient and, hence, cash value than liquid manure, hauling to remote farms and
fields to replace commercial fertilizer application is possible and desirable. Proper management
of applied sludge will result in successful crops and minimal loss of nutrients to surface or
ground waters.
The cover is a limiting factor in covered lagoon cleanout. At least a portion of the cover is
removed to allow equipment access. Removing a complete cover is usually not practical.
Lacking complete access, covered lagoon cleanouts will not remove all of the sludge present.
Therefore, more frequent cleanouts would be expected. Most covered lagoons have been
developed with cleanout intervals of 10-15 years.
Operational Factors: The USDA allows for sludge accumulation by incorporating a sludge
accumulation volume (SAV) in its lagoon design calculations. Table 8-15 shows USDA's ratios
of sludge accumulated per.pound of total solids (TS) added to the lagoon. The higher the rate of
sludge accumulation assumed in a design, the larger the lagoon volume required. There are no
published data to compare sludge accumulation in the first cell of a two-cell lagoon versus
accumulation in a single-cell lagoon. Anecdotal observations suggest that a first cell does not
accumulate sludge faster than a single-cell lagoon as long as the first cell is sized to contain all of
the treatment volume and sludge accumulation-volume (SAV). In theory, a constant volume
first cell should accumulate less sludge over time than a single-cell lagoon because the constant
volume lagoon has a consistently higher microbial concentration than a single-cell lagoon. The
higher concentration should result in the ability to consume new manure organic solids before
they qan settle to become sludge. Also in theory, a covered first cell would accumulate less
sludge due to higher biological activity because a covered lagoon is a few degrees warmer than
an uncovered lagoon.
Table 8-15. Lagoon Sludge Accumulation
Ratios (USDA NRCS 1996)
Animal Type
Layers
Pullets
Swine
Dairy cattle
Sludge Accumulation Ratio
0.0295 fWlb TS
0.0455 fWlb TS
0.0485 fWlb TS
0.0729 fWlb TS
Information from various studies suggests that the USDA values may overestimate actual sludge
accumulation rates. Table 8-16 shows a range of long-term sludge accumulation rates reported
by various researchers. Field studies by both Fulhage and Hoehne (1999) and Bicudo et al.
(1999) show lower accumulation rates than developed by Earth and Kroes (1985) and USDA
NRCS (1996).
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Table 8-16. Lagoon Sludge Accumulation
Rates Estimated for Pig Manure
Source
Fulhage (1990)
Bicudo (1999)
Earth (1985)
USDA(1992)**
Sludge Accumulation Rate
0.002 nrVkg LAW*
0.003 m3/kg LAW*
0.008 m3/kg LAW*
0.012m3/kgLAW*
= live animal weight ** as calculated by Bicudo etal. (1999).
It is important to note that the accumulation rate of sludge is influenced by lagoon design,
influent characteristics, site factors, and management factors. Lagoon design factors such as
lagoon volume, surface fetch, and lagoon depth increase or decrease potential lagoon mixing.
More lagoon mixing encourages greater solids destruction by increasing the opportunity for
bacteria to encounter and degrade solids. Influent factors, including animal type and feed,
determine the biodegradability of manure solids. Highly degradable manure solids are more
completely destroyed, thus accumulating as sludge to a lesser degree. Site temperature and
incident rainfall impact the biological performance of the lagoon. High temperature increases
biological activity and solids destruction. High rainfall can fill the lagoon and reduce retention
time, thus slowing biological destruction of solids. Management factors also affect sludge
accumulation. Increasing animal population, adding materials such as straw or sand used for
animal bedding, or adding process water will reduce the ability of a lagoon to destroy solids and,
therefore, increase the rate of sludge accumulation. Properly managed solids separators can
reduce the quantity of solids reaching the lagoon, hence reducing sludge accumulation
Demonstration Status: First-cell cleanouts are common and have occurred since two-cell
lagoons have been used. In many areas of the country, there are companies that specialize in
lagoon cleaning.
Practice: Solids Buildup in an Uncovered Lagoon
Description: For the purpose of this section, sludge is material settled on the bottom of a lagoon
receiving waste from any animal; it has a total solids content greater than 10 percent, generally
has a high angle of repose when dewatered, and will not readily flow to a pump. This definition
is intended to distinguish sludge from a less concentrated layer of solids above the sludge surface
that can be drawn off with conventional pumping. All lagoons accumulate settleable materials in
a sludge layer on the bottom of the lagoon. Sludge includes organic material not decomposed by
lagoon bacteria and inorganic material such as sand and precipitates. Over time the sludge
accumulation decreases the active treatment volume of a lagoon and negatively impacts the
lagoon performance. Reduced treatment performance increases the rate of sludge accumulation.
Sludge accumulations can eventually fill a lagoon.
Accumulated sludge is removed to restore lagoon treatment and storage capacities. Two general *f
methods of sludge removal, slurry and solid, are described below.
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When managed as a slurry, sludge is resuspended with agitation and pumped to tankers or
irrigation guns for land application. Slurry management is desirable when the sludge mixture can
be pumped to an irrigation gun or hauled a short distance.
Sludge managed as a solid is excavated from the lagoon. Solid sludge is cheaper to haul than
slurry because water, which increases the weight and volume, is not added. Solid sludge can be
spread with conventional manure spreaders or dumped on fields and spread out and disced into
the soil. In drier areas of the country, a lagoon may be withdrawn from service when a parallel
lagoon is restored to service. The lagoon liquids.are pumped off to field application, and the
sludge is allowed to dry. After 4 to 12 months, excavators, backhoes, or bulldozers scrape, push,
pull, or lift the material into trucks or wagons for hauling and spreading. Some lagoons are
designed to be desludged by dragline bucket excavators while still in operation. Draglines work
along the banks of these long, narrow lagoons, excavating sludge and either dropping it into
trucks for hauling or depositing it on the lagoon embankment to dry for later hauling.
Application and Performance: Lagoon cleanout is applicable to all operations that have lagoons,
regardless of location. Reported reductions of P, K, and other nonvolatile elements through a
lagoon are not really reductions at all. The material settles and accumulates in the lagoon,
awaiting later disposal. Compared with lagoon liquids, lagoon sludges have higher
concentrations of all pollutants that are not completely soluble. All reported data suggest that the
sludge is more stable than raw manure based on its reduced volatile solids to total solids ratio .
(VS/TS). Volatile solids are a portion of the total solids that can be biologically destroyed, and
as they are destroyed, the VS/TS ratio declines. Some organic N associated with heavier and
nondegradable organics also settles into the lagoon sludge and stays, resulting in a high-organic
N fraction of total Kjeldahl N (TKN) in settled solids.
As anaerobic digestion of manure changes the solution chemistry in a lagoon, materials such as
ammonia and P form precipitates with Ca and Mg. Both Fulhage and Hoehne (1999) and Bicudo
et al. (1999) report concentrations of Ca, Mg, P, and K in lagoon sludge at 10 to 30 times that
found in raw manure. Fulhage and Hoehne also reported that Cu and Zn settle and concentrate to
40 to 100 times the concentration found in lagoon liquid.
Martin (1999), in a review and analysis of factors affecting pathogen destruction, found that time
and temperature controlled the die-off rate of pathogens. Sludge that has been in a lagoon for 10
years is expected to have very low concentrations of pathogens, and those would be associated
with the most recent 90 to 180 days of settling.
Advantages and Limitations: The advantage of lagoon cleanout is that removal of sludge
restores the volume of a lagoon that is necessary for design treatment and storage capacities.
One of the limitations is that sludge disposal is ignored in most nutrient management plans.
Sludge is a concentrated, nutrient-rich material. The nutrients in the sludge, if applied to the
same cropland historically receiving lagoon liquids, could easily exceed the planned application
rate of nutrients. Phosphorus and other relatively insoluble nutrients are more concentrated than
N in sludge and become the basis of planning proper use and disposal of the sludge.
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Ideally, sludge will be managed as a high value fertilizer in the year it is applied. As the sludge
has a higher nutrient and,, hence, cash value than liquid manure, hauling to remote farms and
fields to replace commercial fertilizer application is possible and desirable. Proper management
of applied sludge will result in successful crops and minimal loss of nutrients to surface or
ground waters.
Operational Factors: The USDA allows for sludge accumulation by incorporating a sludge
accumulation volume (SAY) in its lagoon design calculations. Table 8-15 shows USDA's ratios
of sludge accumulated per pound of total solids (TS) added to the lagoon. The Higher the rate of
sludge accumulation assumed in a design, the larger the lagoon volume required.
Information from various studies suggests that the USDA values may overestimate actual sludge
accumulation rates. Table 8-16 shows a range of long-term sludge accumulation rates reported
by various researchers. Field studies by both Fulhage and Hoehne(1999) and Bicudo et al.
(1999) show lower accumulation rates than were developed by Earth and Kroes (19851 and
USDA NRCS (1996). - • '
It is important to note that the accumulation rate of sludge is influenced by lagoon design,
influent characteristics, site factors, and management factors. Lagoon design factors such as
lagoon volume, surface fetch, and lagoon depth increase or decrease potential lagoon mixing.
More lagoon mixing encourages greater solids destruction by increasing the opportunity for
bacteria to encounter and degrade solids. Influent factors, including animal type and feed,
determine the biodegradability of manure solids. Highly degradable manure solids are more
completely destroyed, thus accumulating as sludge to a lesser degree. Site temperature and
incident rainfall impact the biological performance of the lagoon. High temperature increases
biological activity and solids destruction. High rainfall can fill the lagoon and reduce retention
time, thus slowing biological destruction of solids. Management factors also affect sludge
accumulation. Increasing the animal population, the addition of materials such as straw or sand
used for animal bedding, or the addition of process water will reduce the ability of a lagoon to
destroy solids and increase the rate of sludge accumulation. Properly managed solids separators
can reduce the quantity of solids reaching the lagoon, thereby reducing sludge accumulation.
Mixing a lagoon before land application will suspend some of the sludge solids, causing them to
be pumped out sooner rather than later.
Demonstration Status: Lagoon cleanouts are common and have occurred since lagoons have
been used. Companies'that specialize in lagoon cleaning are found in many areas of the country.
Practice: Trickling Filters
Description: Trickling filters are currently being evaluated for use at animal feeding operations
(AFOs) to address the high concentrations of organic pollutants in AFO wastewater. The
technology is a type of fixed-growth aerobic biological treatment process. Wastewater enters the
circular reactor and is spread over media that support biological growth. The media are typically
crushed rock, plastic-sheet packing, or plastic packing of various shapes. Wastewater
contaminants are removed biologically.
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Filter Medium
Feedpipe
Untreated Wastcwater
Effluent Channel
Figure 8-9. Trickling Fflter
The top surface of the media bed is exposed to sunlight, is in an aerobic state, contains
microorganisms that are in a rapid growth phase, and is typically covered with algae. The lower
portion of the bed is in an anaerobic state and contains microorganisms that are hi a state of
starvation (i.e., microorganism death exceeds the rate of reproduction). The biofihn covering the
filter medium is aerobic to a depth of only 0.1 to 0.2 millimeters; the microbial film beneath the
surface biofihn is anaerobic. As wastewater flows over the microbial film, organic matter is
metabolized and absorbed by the film. Continuous air flow is necessary throughout the media
bed to prevent complete anaerobic conditions (Viessman, 1993).
Components of a trickling filter include a rotary distributor, underdrain system, and filter
medium. Untreated wastewater enters the filter through a feedpipe and flows out onto the filter
media via distributor nozzles, which are located throughout the distributor. The distributor
spreads the wastewater at a uniform hydraulic load per unit area on the surface of the bed. The
underdrain system, typically consisting of vitrified clay blocks, carries away the treated effluent.
The clay blocks have entrance holes that lead to drainage channels and permit the circulation of
air through the media bed. Figure 8-9 below shows a cutaway of a typical trickling filter.
Rock media beds can be up to 200 feet hi diameter and 3 to 8 feet deep, with rock sizes ranging
from 1 to 4 niches. Plastic media beds are narrower and deeper, ranging from 14 to 40 feet deep
(Viessman, 1993). These systems look more like towers than conventional rock-media systems.
It is also common to have single-stage or two-stage systems for N removal. A two-stage system
allows for greater flexibility because each stage can be operated independently and optimized
accordingly. Flow capacity of trickling filters can range between 200 and 26,000 gallons per day;
however, units can be installed in parallel to handle larger flows (AWT Environment).
' 8-92
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Application and Performance: Traditionally, the trickling filter medium has been crashed rock or
stone; however, this type of media occupies most of the volume in a filter bed, reducing the void
spaces for air passage and limiting surface area for biological growth. Many trickling filters now
use a chemical-resistant plastic medium because it has a greater surface area and a large
percentage of free space. These synthesized media forms offer several advantages over naturally
available materials, particularly in terms of surface contact area, void space, packing density, and
construction flexibility (Viessman, 1993).
Although stone-media trickling filters are not as common, they are still used in shallow filters.
BOD loads, expressed in terms of pounds of BOD applied per unit of volume per day, are
typically 25 to 45 pounds per 1,000 ft3 per day for single-stage stone filters and 45 to 65 pounds
per 1,000 ft3 per day/day for two-stage stone filters (based on the total media volume of both
filters). The recommended hydraulic load ranges from 0.16 gallons per minute per ft2 to 0.48
gallons per minute per ft2 (Viessman, 1993).
Other shallow filters use random packing (e.g., small plastic cylinders, 3.5 x 3.5 inches), with a
specific surface area of 31 to 40 fWft3 and a void space of 91 to 94 percent. Deep filters use
corrugated PVC plastic sheets that are 2 feet wide, 4 feet long, and 2 feet deep stacked on top of
each other in a crisscross pattern. The specific surface area ranges from 26 to43 tf/fi3 and a void
space of approximately 95 percent. The BOD loads for plastic media towers are usually 50
pounds-per-l^OOO-f^per-day^or greater with surface hydraulic loadings of 1 gpm/ft2 or greater
(Viessman, 1993).
A single or two-stage trickling filter can.remove,N through,biologicaljiitrification. The
nitrification process uses oxygen and microorganisms to convert ammonia to nitrite nitrogen,
which is then converted to nitrate nitrogen by other microorganisms. Nitrate nitrogen is less
toxic to fish and can be converted to nitrogen gas, which can be released to the atmosphere
through denitrification, a separate anaerobic process following nitrification. Note that trickling
filters are not capable of denitrifying.
A single-stage trickling filter removes BOD in the upper portion of the unit while nitrification
occurs in the lower portion. A two-stage system removes BOD in the first stage while
nitrification occurs in the second stage. Trickling filters do not typically remove P, but can be
adapted to remove P from the wastewater effluent by chemical precipitation following BOD
removal and nitrification (AWT Environment, ETI, 1998).
It is critical to have a properly designed trickling filter system. An improperly designed system
can impact treatment performance and effluent quality. Media configuration, bed depth,
hydraulic loading, and residence time all need to be carefully considered when designing a
trickling filter system (Viessman, 1993).
In a study using municipal wastewater, the average BOD removal was greater than 90 percent
and TSS removal was greater than 87 percent using a trickling filter. The average effluent BOD
concentration was 13 mg/L, while the average effluent TSS concentration was 17 mg/L (AWT
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Environment). In another similar study that included municipal and dairy waste, BOD and TSS
concentrations were slightly greater, but never exceeded 100 mg/L (Bio-Systems, 1999).
In another study using municipal wastewater and an anaerobic upflow filter prior to the trickling
filter, the average effluent BOD and TSS concentrations both ranged from 5 to 10 mg/L, and. the
total N removal ranged from 80 to 95 percent. Pathogen reduction for this particular system is
expected to be good, due to the upflow filter component. The estimated cost for this system is •
approximately $18,000 in annualized present day (Year 2000) costs (annualized over 20 years
and not including design and permitting) (City of Austin, 2000).
Information on the reduction of pathogens, antibiotics, and metals hi trickling filters is not
available, but it is expected to be minimal based on engineering judgment.
Advantages and Limitations: An advantage of operating a trickling filter is that it is a relatively
simple and reliable technology that can be installed in areas that do not have a lot of space for a
treatment system. This technology is also effective in treating high concentrations of organics
and nutrients. It can be cost-effective because it entails lower operating and maintenance costs
than other biological processes, including less energy and fewer skilled operators. The wasted
biomass, or sludge, can be processed and disposed of, although it contains high concentrations of
nutrients. Finally, it also effectively handles and recovers from nutrient shock loads (ETI, 1998).
Disadvantages of operating a trickling filter are that additional treatment may be needed to meet
stringent effluent limitations, the operation generates sludge that needs to be properly disposed
of, poor effluent quality results if the system is not properly operated, and regular operator
attention is needed. The system is susceptible to clogging from the biomass as well as odors and
flies. The high solids content of CAFO waste would most likely require solids separation prior
to treatment to also prevent clogging. Only the liquid waste may be treated in this system. In
addition, a high investment cost may also prevent certain farms from installing this technology
(EH, 1998).
Operational Factors: Trickling filters are typically preceded by primary clarification for solids
separation and are followed by final clarification for collection of microbiological growths that
slough from the media bed. They can also be preceded by other treatment units such as septic
tanks or anaerobic filters. Trickling filters effectively degrade organic pollutants, but can also be
designed to remove N and P from the wastewater. .
Trickling filters are relatively simple to operate, are lower in cost than other biological treatment
processes, and typically operate at the temperature of the wastewater as modified by that of the
air, generally within the 15-25 °C range. A high wastewater temperature increases biological
activity, but may result hi odor problems. Cold wastewater (e.g., 5-10°C) can significantly
reduce the BOD removal efficiency (Viessman, 1993).
Demonstration Status: Trickling filters are most commonly used to treat municipal wastewater,
although the technology is applicable to agricultural wastewater treatment. They are best used to
treat wastewaters with high organic concentrations that can be easily biodegraded. EPA was not
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able to locate any AFO facilities that currently operate trickling filters; however, based on the
information gathered, several wastewater treatment vendors market this technology to such
facilities.
Practice: Fluidized Bed Incinerators
Description: Fluidized bed incinerators (FBIs) are
currently being evaluated for use at CAFOs given the
high volume of manure they generate. The technology is
typically used for wastewater sludge treatment (e.g.,
municipal sludge), but may be used for wastewater
treatment. The main purpose of an FBI is to break down
and remove volatile and combustible components of a
waste stream and to reduce moisture. Its most prominent
application to CAFO industries would be for animal
waste disposal and treatment, because manure has a
higher solids content than wastewater from CAFO
operations.
^.Exhaust and Ash
Feed Inlet
Ait Inlet
Preheat Burner
Figure 8-10. Fluidized Bed
Incinerator
An FBI is a vertical, cylindrical shaped apparatus that
requires media (typically sand), injected air, and an
influent fuel to operate. An FBI contains three basic
zones: a windbox, a sand bed, and a freeboard reactor chamber. Air enters the windbox and
moves upward into the media bed through orifices called "tuyeres" at a pressure of 3 to 5 pounds
per square inch. The injected-airacts to fluidize the bed and to generate combustion. The term
"fluidized bed" refers to the "boiling" action of the sand itself, which occurs when air is injected
into the reactor. The fuel, or animal waste, directly enters the fluidized sand bed and is mixed
quickly within the bed by the turbulent action. Any moisture in the animal waste evaporates
quickly, and the sludge solids combust rapidly. Combustion gases and evaporated water flow
upward through the freeboard area to disengage the bed material and to provide sufficient
retention time to complete combustion. Gases and ash exit the bed out the top of the FBI. Exit
gases may be used to preheat the injected air or may be recovered for energy. Exit ash is
removed from exit gas in an air pollution device such as a venturi scrubber. Ash can either be
disposed of or reused (typically as fertilizer) depending on its characteristics (Metcalf and Eddy,
Prior to injection, the sand media is kept at a minimum temperature of 1300 °F and controlled at
between 1400 and 1500 °F during treatment. This temperature range varies with specific design
criteria. The FBI typically ranges in size from 9 to 25 feet in diameter; the media bed is typically
2.5 feet thick, when settled (Metcalf and Eddy, 1991). The system has a capacity of up to 30 tons
per hour (UNIDO, 2000). The combustion process is optimized by varying the animal waste and
aur flow, with exit gas retention times greater than 1 second and solids retention times greater
than 30 minutes (Versar, 2000). Figure 8-10 represents a typical FBI.
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Application and Performance: Animal waste enters the FBI and quickly combusts in the media
bed. Organic constituents of the waste are burned to produce carbon dioxide and water, while
volatile pollutants are evaporated and captured in the air control device. Solid material may be
recycled through the system for further treatment. The ash contains many of the pollutants in the
animal waste itself, although waste volume is reduced and most of the N in the waste is
evaporated. The ash will still contain high levels of metals, P, and K.
The high temperature of the system typically eliminates the spread of pathogens, reducing
biosecurity concerns. Similarly, any antibiotics or hormones remaining.in the waste will also be
broken down and reduced. Although FBIs operate at very high temperatures, they typically
operate at lower temperatures than other types of incinerators, which results in lower air
emissions, particularly of NOX compounds and volatile organic compounds (VOCs).
Advantages and Limitations: Fluidized bed incineration is an effective and proven technology for
reducing waste volume and for converting the waste to useful products (e.g., energy). Resulting
ash may be used as an end- product fertilizer, or as an intermediate product used in
manufacturing commercial fertilizers. Animal waste incineration eliminates aesthetic concerns
(e.g., odors) as well as nuisan'ce concerns (e.g., pest attraction) (Versar, 2000).
r* • ' ' ,
Although fluidized bed incineration is viewed as an efficient system, it is very sensitive to
moisture content and fuel particle size. The higher the moisture content, the less efficient the
system is because the moisture acts to depress the reactor temperature, thereby reducing
combustion capabilities. Moisture can be reduced in animal waste by combining the waste with
other biomass such as wood chips or straw., Air drying or dewatering the animal waste also
reduces moisture content before treatment in the FBI. Blockages may often occur in input and
output pipes triggering shut-down and maintenance (Versar, 2000).
Air emissions must also be considered when operating any type of .incinerator. Organic and N
compounds are easily removed from the waste; however, they are then emitted to the air,
potentially creating a cross-media impact if not properly controlled. Furthermore, nutrients such
as P, K, and metals typically remain in the ash and are not treated. Finally, FBIs entail high
operating and maintenance costs, especially compared with other types of incinerators (Versar,
2000).
Operational Factors: As discussed above, FBIs are most sensitive to moisture content and fuel
particle size. The less moist the influent fuel, the more efficient the system is. Acceptable
influent moisture levels range from 15 to 20 percent moisture. Fuel particle size should also be
minimised to avoid clogging the system. Another consideration is that depending on the metals
concentrations and local regulations, the ash, if intended for disposal, may need to be handled as
hazardous waste (Versar, 2000).
FBI costs depend on size and capacity. Capital costs can range from approximately $5 to 25
million for a 5-ton-per-hour and a 30-ton-per-hour FBI, respectively (UNIDO, 2000). FBIs are
complex technologies and require operation by trained personnel. Because of this, FBIs are more
economical for medium to large facilities, or when operated in cooperation with several
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businesses that are able to provide fuel sources. Therefore, FBIs may not be a cost-effective
waste management technique for an individual farm, but, when operated on a larger scale, they
may prove to be cost-effective. Capital and annual operating costs are generally higher for FBIs
than for other types of incinerators because of the sensitive design parameters (e.g., moisture
content and solid particle size). On the other hand, the system operates efficiently, and energy
can usually be recovered from the process and may be sold to another party or used to reduce on-
site operating costs.
Demonstration Status: ERG is not aware of any U.S. feedlots currently operating FBIs or
sending animal waste to larger-scale municipal or private FBIs. According to information
gathered for this program, FBIs are more commonly used in Europe and in Japan to treat animal
waste, although some U.S. companies using waste-to-energy technology may be operating FBIs
using animal waste with other fuel sources. FBIs are most commonly used in the United States
to manage municipal sludge.
In a study done to assess the engineering and economic feasibility of using poultry litter as a fuel
to generate electric power, researchers found that combusting poultry litter (combined with wood
chips) can be an effective waste-to-energy technology (Versar, 2000). Although the study did not
specifically evaluate fiuidized bed incineration, the application and results are expected to be
similar. The study found litter samples to have a heat content between 4,500 and6,400 BTU per,:
pound at approximately 16 percent moisture, which is a slightly higher content than the wood
chips alone. The ash contenrof the litter was reportedto be between 9 and 20 percent, which is
significantly higher than the wood chips alone. However, although the air emissions data in this
study were considered preliminary, they showed that the facility could trigger air permitting
requirements. The study also found that poultry litter ash may be classified as hazardous waste
under individual state regulations (Versar, 2000).
Practice: Constructed Wetlands
Description: Constructed wetlands (CWs) can be an important tool in the management of animal
waste by providing effective wastewater treatment in terms of substantial removal of suspended
solids, 5-day biochemical oxygen demand (BOD5), fecal coliform, and nutrients such as N and P
(CH2M Hill, 1997). The treatment process in CWs generates an effluent of better quality that
can be applied on agricultural land or discharged to surface waters (CH2M Hill, 1997).
Wastewater treatment in CWs occurs by a combination of mechanisms, including biochemical
conversions, settling/filtration, litter accumulation, and volatilization. Removal of pollutants in
CWs is facilitated by shallow water depth (which maximizes the sediment-water interface), slow
flow rate (which enhances settling), high productivity, and the presence of aerobic and anaerobic
environments (Cronk, 1996).
Wetland media (soil, gravel) and vegetation provide a large surface area that promotes microbial
growth. Biochemical conversion of various chemical compounds through microbial activity is
the main factor in the wetland treatment process. Through microbial activities, organic N is
converted to ammonia (ammonification), which is used by plants as a nutrient; ammonia is
converted to nitrate and nitrite (nitrification), which is used by microbes and some plants for
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growth; and N is volatilized (denitrification) and is lost to the atmosphere (CH2M Hill, 1997).
Ammonia may be removed through volatilization, uptake by plants and microbes, or oxidized to
nitrate. Volatilization of ammonia in CWs appears to be the most significant mechanism for N
removal for animal waste treatment (Payne Engineering and CH2M Hill, 1997).
" *
Phosphorus removal is achieved mainly by fixation by algae and bacteria, plant uptake, and
adsorption onto sediments (Cronk, 1996) when oxidizing conditions promote the complexing of
nutrients with iron and aluminum hydroxides (Richardson, 1985). Plant uptake of P is only a
short-term sink because plant P is rapidly released after the death of plant tissues (Payne
Engineering and CH2M Hill, 1997). Fixation of P by microbes ultimately results in the storage of
P in the bottom sediments (Corbitt and Bowen, 1994), yet they may become saturated with P,
resulting in an export of excess P (Richardson, 1985).
Rooted emergent aquatic plants are the dominant life form in wetlands (Brix, 1993) and are the
only aquatic plants recommended for planting in CWs used for animal'waste treatment (Payne
Engineering and CH2M Hill, 1997). These aquatic plants have specialized structures that allow
air to move in and out as well as through the length of the plant, have roots that allow adsorption
of gases and nutrients directly from the water column, and are physiologically tolerant to
chemical products of an anaerobic environment (Brix, 1993). For these reasons, emergent aquatic
plants can survive and thrive in wetland environments. The most common emergent aquatic
plants used in CWs for animal waste treatment are cattail (Typha spp.), bulrush (Scirpus spp.),
and common reed (Phragmites spp.) (CH2M Hill and Payne Engineering, 1997).
Roles of emergent aquatic plants in the wastewater treatment process include the following:
(1) providing a medium for microbial growth and a source of reduced carbon for microbial
growth; (2) facilitating nitrification-denitrification reactions; (3) assimilating nutrients into then-
tissue; (4) facilitating entrapment of solids and breakdown of organic solids; and (5) regulating
water temperature by shading the water (Payne Engineering and CH2M Hill, 1997). The vascular
tissues of these plants move oxygen from overlying water to the rhizosphere and thus provide
aerobic microsites (within the anaerobic zone) in the rhizosphere for the degradation of organic
matter and growth of nitrifying bacteria (Brix, 1993). Dissolved nitrates, from nitrification, can
then diffuse into the surrounding anaerobic zone where denitrification occurs. Furthermore,
wetland macrophytes remove small amounts (<5 percent, Hammer, 1992) of nutrients, for
nutritional purposes, by direct assimilation into their tissue. Removal of nutrients, however,
increases slightly in CW systems that incorporate periodic harvesting of plants (Hammer, 1992)
or may be considerably higher (67 percent) in specially designed systems that maximize influent-
root zone contact (Breen, 1990).
The two principal types of CWs for treating wastewater are surface flow (SF) and subsurface
flow (SSF) systems. The SF systems are shallow basins or channels, carefully graded to ensure
uniform flow, planted with emergent vegetation, and through which water flows over the surface
at relatively shallow (~30 cm) depths. The SSF systems consist of a trench or bed with, a barrier
to prevent seepage, planted emergent vegetation growing in a permeable media (soil, gravel)
designed such that the wastewater flows horizontally through the media, with no open surface
flow. The base media and plant roots provide large surface areas for biofilm growth and thus,
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functions somewhat like a rock trickling filter at a municipal wastewater treatment plant (Payne
Engineering and CH2MffiU, 1997).
Some authors also refer to the SF system as the free water surface system, while the SSF type is
also referred to as the vegetated rock-reed filter, vegetated submerged bed system, gravel-bed
system, and root-zone system. Compared with SSF systems, the SF wetlands are capable of
receiving a wider range of wastewater loads, have lower construction costs, and are relatively
easy to manage (Payne Engineering and CH2M Hill, 1997). Additionally, mass removal of
ammonia-N, the major form of N in animal wastewater (CH2M Hill and Payne Engineering,
1997), in SSF wetlands is significantly less compared with the SF type because there is less time
and oxygen to support necessary nitrification reactions (USEPA, 1993). For these reasons, the SF
system is the most commonly used wetland type for treating animal waste (Payne Engineering
and CH2M Hill, 1997) and is the only one recommended for animal waste treatment by the
USDA Natural Resources Conservation Service (USDA NRCS, 1991).
Application and Performance: A database, developed by CH2M Hill and Payne Engineering
(1997), containing design, operational, and monitoring information from 48 livestock CW
systems (in the United States and Canada), indicates that CWs have been and continue to be used
successfully to treat animal waste, including wastewater from dairy, cattle, swine, and poultry
operations. The majority of CW sites included in the database have begun operations since 1992.
SF systems constitute 84 percent of cells hi the database, and the remainder consists of SSF or."
other wetland systems. Cattail, bulrush, and reed, in that order, dominate the aquatic vegetation .
planted in the surveyed CWs.
Typically, effluent from a CW treating animal waste is stored in a waste storage lagoon. Final
dispersal occurs through irrigation to cropland and pastureland, though the potential for direct
discharge of effluent exists. Direct discharge may, however, require a permit under the EPA's
National Pollutant Discharge Elimination System.
A performance summary of CWs used for treating animal waste indicates a substantial reduction
of suspended solids (53 to 81 percent), fecal coliform (92 percent), BOD5 (59 to 80 percent),
ammonia-N (46 to 60 percent), and N (44 to 63 percent) for wastewater from cattle feeding,
dairy, and swine operations (CH2M Hill and Payne Engineering, 1997). In a study by Hammer et
al. (1993), swine effluent was treated hi five CW cells, located below lagoons, that were
equipped with piping that provided a control for variable application rates and water level control
within each cell. Performance data indicate notable (70 to 90 percent) pollutant removal rates and
reliable treatment of swine lagoon effluent to acceptable wastewater treatment standards for
BOD5, suspended solids, N, and P during the first year of the reported study.
Removal efficiency of N is variable depending on the system design, retention time, and oxygen
supply (Bastian and Hammer, 1993). Low availability of oxygen can limit nitrification, whereas a
lack of a readily available carbon source may limit denitrification (Corbitt and Bowen, 1994).
Fecal coliform levels are significantly reduced (>90 percent) by sedimentation, filtration,
exposure to sunlight, and burial within sediments (Gersberg et al., 1990). Compared with dairy
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systems, higher reduction of pollutants have been reported for swine wastewater treatment in
CWs, probably because loading rates have tended to be lower at swine operations (Cronk, 1996).
Advantages and Limitations: In addition to treating wastewater and generating water of better
quality, CWs provide ancillary benefits such as serving as wildlife habitat, enhancing the
aesthetic value of an area, and providing operational benefits to farm operators and their
neighbors (CH2M Hill, 1997). CWs, in contrast to natural wetlands, can be built with a defined
(desired) composition of substrate (soil, gravel) and type of vegetation and, above all, offer a
degree of control over the hydraulic pathways and retention times (Brix, 1993). An SF system is
less expensive to construct than an SSF system, the major cost difference being the expense of
procuring and transporting the rock or gravel media (USEPA, 1993). An SSF system, however,
has the advantage of presenting an odor- and insect-free environment to local residents.
Major limitations include a need for relatively large, flat land areas for operation (Hammer,
1993), a possible decrease in SF system performance during winter in temperate regions (Brix,
1993), and a reduction in functional sustainability of the SSF systems if the pore spaces become
clogged (Tanner et al., 1998). Other limitations include (1) an inadequacy of current designs of
SF systems to store flood waters and use stored water to supplement low stream flows in dry
conditions and (2) potential pest problems and consequent human health problems from
improperly designed or operated SF systems (Hammer, 1993). Moreover, because CW
technology for animal waste treatment is not well established, long-term status and effects,
including accumulation of elemental concentrations to toxic levels, are poorly documented.
Further research is needed to better understand the nutrient removal mechanisms in CWs so that
improved designs and operating criteria can be developed.
Operational Factors: Because untreated wastewater from AFOs has high concentrations of
solids, organics, and nutrients that would kill most wetland vegetation, wastewater from AFOs is
typically pretreated in a waste treatment lagoon or settling pond prior to discharge to a CW
(Payne Engineering and CH2M Hill, 1997). Incorporating a waste treatment lagoon in the
treatment process reduces concentrations of BOD5 and solids considerably (>50 percent) and
provides storage capacity for seasonal application to the wetlands (Hammer, 1993). ,
Figure 8-11 shows the typical components and a typical treatment sequence of a CW.
Constructed wetlands maybe built with cells that are parallel or in a series. Construction of cells
needs to be determined by the overall topography as well as by the drainage slope of individual
cells to maintain shallow water depth for the wetland plants (CH2M Hill and Payne Engineering,
1997). The land slope should be small (<0.5 percent), and the length-to-width ratios should be
between 1:1 and 10:1, with an ideal ratio being 4:1 (USDA NRCS, 1991). Data for the surveyed
CWs, reported by CH2M Hill and Payne Engineering (1997), indicate the following average
Animal
Waste
Source
Waste
Treatment
Lagoon
Constructed
Wetland
Waste
Storage
Pond
Irrigation
(Possibly Direct
Discharge)
Figure 8-11. Schematic of Typical Treatment Sequence Involving a Constructed Wetland
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design conditions: water depth of 38 cm; bottom slope of 0.7 percent; length-to-width ratio of
6.5:1; hydraulic loading rate of 4.7 cm/day, and a size of 0.03 hectare.
Design criteria for CWs for animal waste treatment are described in USDA NRCS (1991),
including methods to determine the surface area of a proposed wetland, the NRCS Presumptive
Method is based on an estimate of BOD5 loss in the pretreatment process, which is used to
calculate BOD5 concentration in the pretreatment effluent. Size of the wetland is then
determined based on a loading rate of 73 kg BOD5/ha/day that would achieve a target effluent of
<30 mg/L of BOD?, <30 mg/L total suspended solids, and <10 mg/L ammonia-N. The NRCS
Field Test Method is based on laboratory data for average influent BODS concentration to the
CW. The influent BODS concentration, together with average temperature data, is used to
determine the hydraulic residence time needed to obtain a desired effluent BOD5 concentration.
Advances in research and technology of CW during the 1990s have provided additional
information to allow modification of the USDA NRCS (1991) methods. CH2M Hill and Payne
Engineering (1997) developed the Modified'-Presumptive^USDA-NRCS'Method, which takes into
account pollutant mass loading and volume of water applied, and relates the results to a data
table developed from existing CWs for animal waste treatment. The Field Test Method #2 was
also proposed by CH2M Hill and Payne Engineering (1997) based on the areal loading equation
developed by Kadlec and Knight (1996), which includes rate constants specific to concentrated
animal waste.
Operation and maintenance requirements for CWs include maintenance of water level in the
wetland cells, monitoring water quality of influent and effluent, regular inspection of water
conveyance and control structures to ensure proper flow, and maintenance of the embankments to
avoid damage from rodents.
Demonstration Status: CWs have been demonstrated successfully as a management technology
treatment for swine waste (Maddox and Kinglsey, 1990; Hammer et al., 1993) and dairy waste
(Chen et al., 1995; Tanner et al., 1995; Schaafsma et al., 2000), and have been relatively less
successful in the treatment of poultry waste (Hill and Rogers, 1997). Results of several other
successful case studies, performed in several regions of North America, are reported in DuBowy
and Reaves (1994), DuBowy (1996), and Payne Engineering and CH2M Hill (1997).
Practice: Vegetated Filter Strips
Description: Vegetated filter strips are an overland wastewater treatment system. They consist of
strips of land located along a carefully graded and densely vegetated slope that is not used for
crops or pasture. The purpose of a vegetated filter strip is to reduce the nutrient and solids
content of wastewater and runoff from animal feeding operations. The filters are designed with
adequate length and limited flow velocity to promote filtration, deposition, infiltration,
absorption, adsorption, decomposition, and volatilization of contaminants.
The wastewater is distributed evenly along the width of a slope in alternating application and
drying periods. The wastewater may be applied to the slope by means of sprinklers, sprays, or
' 8-101
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Bvmpotmspiniia&
CoHfictfan
Cbsnncl
Gncs cover crop
Figure 8-12. Schematic of a Vegetated Filter Strip
Used to Treat AFO Wastes
gated, slotted, or perforated pipe. As the wastewater flows down the slope; suspended solids are
deposited and some nutrients are absorbed into the vegetation. The effluent from the system is
collected in a channel at the bottom of the slope and then discharged (see Figure 8-12).
Application and Performance: The design of a vegetated filter strip is typically based on the
BOD concentration of the wastewater (Metcalf and Eddy, 1991). The total treatment area
required is calculated from the hydraulic loading rate, assumed length of slope (generally 100 to
150 feet), and an operating cycle. The operating cycle and application rate can be varied to
optimize the system. An operating cycle of 1 day is typical, with 8 to 12 hours of application and
12 to 16 hours of drying. Ammonia removal from primary effluent can be expected to vary
inversely with the ratio of application period to drying period. A properly designed system can
remove up to 95 percent of ammonia. The application rate is critical for considering BOD
removal because it is important to maintain aerobic conditions that are required for microbia.1
decomposition. Too high an application rate can create anaerobic conditions because the oxygen
transfer through natural aeration from the atmosphere will be insufficient.
The vegetative cover should be dense in growth, such as a grass, and well suited to the climatic
conditions. The vegetation must be dense enough to slow the wastewater flow to allow adequate
treatment and prevent erosion. Consideration should also be given to the nutrient uptake
potential of the vegetation to maximize nutrient removal rates.
Proper grading is also critical to the design of a vegetated filter strip to prevent the channeling of
wastewater and allow for efficient treatment. Sites with an existing slope of 2 to 6 percent are
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best suited for vegetated filter strips to keep regrading costs to a minimum without causing water
to pond.
Vegetated filter strips are also best suited to sites that have low permeability soils to prevent
wastewater from infiltrating the subsurface. In areas where soils are relatively permeable., it may
be necessary to amend the existing soils or install an impermeable barrier.
A study conducted to determine the effectiveness of milkhouse wastewater treatment using a
vegetative filter strip at a dairy farm in Vermont (Clausen and Schwer, 1989) found that
removals of total suspended solids, total P, and total Kjeldahl N were 92 percent, 86 percent, and
83 percent, respectively. However, the total P concentration in the effluent was more than 100
times greater than the average P concentration of streams draining agricultural areas in the
northeast. Moreover, only 2.5 percent of the total input of P and 15 percent of the input of N
were removed in the vegetation.
The EPA Chesapeake Bay Program studied the use of vegetative filter strips to reduce
agricultural nonpoint source pollutant inputs to the bay (Dillaha et al., 1988). A series of nine
experimental field plots were constructed,-each containing a simulated feedlot source area and a
vegetated filter strip of known length. A rainfall simulator was used to produce runoff, which
was collected from the base of each vegetated filter strip. Analysis indicated that 81 to 91
percent of incoming sediment, 58 to 69 percent of the applied P, and 64 to 74 percent of the
, applied N were removed.
Advantages and Limitations: Compared with many treatment technologies, vegetated filter strips
effectively reduce the nutrient and solids concentration of wastewater with relatively low
construction and maintenance costs. This is particularly true for sites where available land is
well suited for such a system.
However, to effectively treat high volumes of wastewater, such as from a milking parlor,
excessive acreage may be required. In addition, because overland flow systems such as vegetated
filter strips depend on microbiological activity at or near the surface of the soil, cold weather
adversely affects their performance. Winter use of this in colder climates will therefore be
limited and an appropriate amount of wastewater storage will be required. Storage is
recommended when the average daily temperature is below 32°F.
Operational Factors: Maintenance of a vegetated filter strip consists of periodic removal of the
vegetative growth, which contains many of the nutrients. The biomass has various potential
uses—as forage, fiber, or mulch, for example. In addition, the slope needs to be periodically
inspected and regraded to ensure a level flow surface and prevent channeling and erosion.
Demonstration Status: Vegetated filter strips have been used to treat milkhouse wastewater in
New York and North Carolina. They have also been used to treat a variety of other wastes,
including feedlot runoff. -
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Practice: Composting—Aerobic Treatment of Solids
Description: Composting is the aerobic biological decomposition of organic matter. It is a
natural process that is enhanced and accelerated by the mixing of organic waste with other
ingredients in a prescribed manner for optimum microbial growth. Composting converts an
organic waste material into a stable organic product by converting N from the unstable ammonia
form to a more stable organic form. The end product is safer to use than raw organic material
and one that improves soil fertility, tilth, and water holding capacity. In addition, composting
reduces the bulk of organic material to be spread, improves its handling properties, reduces odor,
reduces fly and other vector problems, and can destroy weed seeds and pathogens. There are
three basic methods of composting: windrow, static pile, and in-vessel.
Windrow composting consists of placing a mixture of raw organic materials in long, narrow
piles or windrows, which are agitated or turned on a regular basis to facilitate biological
stabilization. Windrows aerate primarily by natural or passive air movement (convection and
gaseous diffusion). Windrow composting is suitable for large quantities of organic material. For
composting dense materials like manure mixtures, windrows are usually no more than 3 feet high
and 10 to 20 feet wide. The equipment used for turning, ranging from a front-end loader to an
automatic mechanical turner, determines the size, shape, and spacing of the windrows.
The static pile method consists of mixing the compost materiaTand then stacking the mix on
perforated plastic pipe or tubing through which air is drawn or forced. Forcing air (by suction or
positive pressure) through the compost pile may not be necessary with small compost piles that
are highly porous or with a mix that is stacked in layers with highly porous material. If layering
is not practiced, the materials to be composted must be thoroughly blended before they are placed
in a pile. The exterior of the pile is typically insulated with finished compost or other material.
The dimensions of the static pile are limited by the amount of aeration that can be supplied by the
blowers and by the stacking characteristics of the waste. The pile height generally ranges from 8
to 15 feet, and the width is usually twice the height. The spacing between individual piles is
usually equal to about half the height.
The in-vessel method involves the mixing of manure or other organic waste with a bulking agent
in a reactor, building, container, or vessel, and may involve the addition of a controlled amount
of air over a specific detention time. This method has the potential to provide a high level of
process control because moisture, aeration, and temperature can be maintained in some of the
more sophisticated units (USDA, 1999).
Application and Performance: Composting is an accepted process for the biological stabilization
of the organic material in waste,'providing an alternative to long-term liquid and semisolid
manure storage. It turns waste organic material (dead poultry, manure, garbage, and so forth)
into a resource that can be used as a soil amendment and fertilizer substitute. Proper composting
minimizes nutrient loss while killing pathogenic organisms by process generated heat. For
example, two waste products from a municipal and a dairy source were composted in the lab
under controlled temperature and air flow rates (Hall and Aneshansley, 1997). Researchers
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found that maintaining high and constant temperatures destroys pathogens and accelerates
decomposition.
In general, only manure from confined animals is available for composting. Usually manure
must be dewatered or mixed with sawdust or wood chips to lower the moisture content, which
may range from 60 to 85 percent. The presence of plant nutrients such as N, P and K- the
organic content; and the absence of significant levels of heavy metals makes animal manure a
very attractive raw material for producing compost. In-vessel composting has been conducted
successfully with dairy cattle manure, swine manure, horse manure, and poultry and turkey litter
Advantages and Limitations: Compost and manure are both good soil conditioners that contain
some fertilizer value. On a growing number of farms, however, manure is considered more of a
liability than an asset. Animal waste generators may find themselves with surpluses of manure in
the winter, yet lacking manure by spring planting. Odor complaints associated with manure are
common in populated areas. Other concerns include polluted runoff from manure spread on
frozen ground and nitrate contamination of wells.
Composting converts the nutrients in manure into forms that are less likely to leach into ground
water or be earned away by surface runoff. Compost releases its nutrients more slowly than
commercial fertilizers, so it does not burn crops and can feed them over a longer period of time
The nutrient value of manure was demonstrated in a study in which five combinations of
composted cattle feedyard manure and liquid phosphate were appliedTto provide 100 percent of
the P requirement for corn (Auvermann and Marek, 1998).. Five replicates were tested for each
treatment. No significant difference was determined between corn yields in treatment-by-
treatment comparisons, indicating that composted feedlot manure may be an adequate substitute
for chemical fertilizers.
A well-managed composting operation generates few odors and flies, and the heat generated by
the composting process reduces the number of weed seeds contained in the manure. Composting
also reduces the weight, moisture content, and volatility of manure, making it easier to handle
and store. Because of its storage qualities, compost can be held for application at convenient
times of the year. Composted manure and composted manure solids can also be used as bedding
material for livestock.
Different types of in-house, deep litter manure management systems were tested at a 100 000-
chicken high-nse layer operation in Georgia (Thompson et al., 1998). Composting was '
conducted using raw manure, a manure and leaf mixture, and manure and wood chip mixture
The in-house composting was found to reduce the weight and volume of wastes more efficiently
than conventional methods of stacking manure under the house. Wood chip and leaf manure
both had lower moisture content and more concentrated nutrients compared with the raw manure.
Disposal is less of a problem for compost than for manure because there is usually someone
willing to take the compost. One of the strongest incentives for composting is that a market
exists for the product, especially in populated areas. Potential buyers include home gardeners,
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landscapes, vegetable fanners, garden centers, turf growers, golf courses, and ornamental crop
producers. Bulk compost prices range from $7 to $50 per cubic yard, depending on the local
market, compost quality, and the raw materials used.
Countering these advantages are several limitations. Managing and maintaining a composting
operation takes time and money, and compost windrows and storage facilities for raw materials
can take land, and possibly building space, away from other farming activities. When processing
only small volumes of farm wastes, the equipment needed is probably already available on the
farm, but composting may become a very capital- and labor-intensive task for larger operations.
Farmers might need to invest in special composting equipment, which can cost anywhere from
$7,000 to more than $100,000. The main equipment needed for composting on a moderate to
large scale is machinery to construct, mix, and move material in a compost pile or windrow. A
front-end loader and truck may be all that is required. Other equipment, such as chipping or
shredding equipment, a windrow turner, screening equipment, aeration equipment, and a
composting thermometer or temperature probe, might be needed as well.
Although the end product of composting is odor-free, the raw materials used to make compost
may not be. Even the compost piles themselves, if not maintained properly, can become
malodorous. Cold weather slows the composting process by lowering the temperature of the
composting material. Heavy precipitation adds water to the composting mix, and snow and mud
can limit access to windrows.
There is also some ambiguity as to whether manure or compost provides crops with more N.
Compost can contain less than half the N of fresh manure; however; the N in manure is less
stable than that in compost. Farmers must apply more compost than manure to farmland to
achieve Hie same results because compost nutrients are released very slowly. Generally, less than
15 percent of the N in compost is released in the first year.
Last, although compost is a salable product, selling compost involves marketing. This means
searching out potential buyers, advertising, packaging, managing inventory, matching the product
to the customer's desires, and maintaining consistent product quality.
In addition to these general limitations, there are specific limitations associated with composting
different types of animal manure. Wastes containing excessively high water content, such as
poultry manure from egg laying operations and wet manure from free-stall dairy CAFOs, may
require additional processing prior to composting. The conditions for optimal composting (see
Operational Factors below for greater detail) are not always met with these wastes; for example,
the water content is too high (usually greater than 70 percent), the biomass is poorly aerated, and
the C;N ratio is often less than 15:1. In these cases, bulking agents such as wood chips or similar
wood products are added to make the mix more suitable for efficient composting, but bulking
agents must be purchased if not readily available on the farm. Table 8-17 summarizes some of
the key advantages and disadvantages of composting.
Operational Factors: Because composting is a biological process, environmental factors
influence organism activity, thus determining the speed of decomposition and the length of the
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composting cycle. The composting period typically lasts from 3 to 8 weeks for conventional
composting methods under normal operating conditions. Users of some highly controlled
mechanical systems claim to produce compost in as little as 1 week. The length of time depends
upon many factors, including the materials used, temperature, moisture, frequency of aeration,
and ultimate use of the material. Conditions that slow the process include lack of moisture, a'
high C:N ratio, cold weather, infrequent or insufficient aeration, and large or woody materials. A
month-long "curing" period usually follows the active composting stage. Curing continues to
stabilize the compost but at a much slower pace. At this stage, the compost can be stockpiled
without turning or aeration and without the fear of odor problems (Rynk, 2000).
Table 8-17. Advantages and Disadvantages of Composting
Compost is an excellent soil conditioner.
Compost is a salable product
Compost reduces the weight, moisture content, and activity
of manure, making it easier to handle and store.
Composting converts the N content of manure into a more
stable organic form. Manure that has been composted
provides a better carbon/nitrogen ratio (C:N) in the soil,
contains fewer weed seeds, and poses a lower risk of
pollution and nuisance complaints (due to less odor and
fewer flies).
. Composting kills pathogens.
Compost is a suitable bedding substitute.
Land-applied compost has proven to suppress soil-borne
plant diseases without the use of chemical controls.
Some fanners have begun accepting payment (referred to as
"tipping fees") to compost off-site wastes.
Composting is labor and management intensive.
Selling compost involves marketing costs (advertising,
packaging, management, customer service, and so forth).
The composting site, raw materials storage, and compost
storage require a large land area.
Nutrients in compost are in complex form and, therefore,
, need to be mineralized for plant intake; thus a greater volume
of compost is needed to meet crop demands.
Effectiveness is weather dependent.
Large operations require expensive equipment
Odors can be a recurring problem.
Acceptance of off-site organic wastes may result in the
operation being classified as commercial and increase
compliance costs under zoning and environmental
regulations.
The characteristics of the raw organic material are the most important factors determining the
quality of compost, including moisture content, C:N ratio, aeration, material particle size, and
temperature. Acceptable and preferred ranges for nutrient balance (C:N ratio), moisture content,
pH, and bulk density are provided in Table 8-18 (NREAS, 1992). Additional factors considered
when formulating a raw organic material recipe are degradability, odor potential, and cleanness.
For example, swine manure is very odorous and should not be composted on locations prone to
odor complaints. Cleanness refers to the degree of contamination from unwanted materials
(glass and heavy metals), chemicals (pesticides), and organisms (human pathogens). If the
compost is to be sold offsite, the raw material content will greatly affect its market value.
The optimum moisture content for composting varies with particle size and aeration. At high
moisture content, voids fill with liquids and aeration is hindered. Low moisture levels, on the
other hand, retard or stop microbial activity, although some composting occurs with moisture as
low as 25 percent. Depending on the raw materials, there is ultimately a 30 to 60 percent
reduction in volume of the compost material, much of it due to water loss. If the water content
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falls below 40 to 50 percent, water should be added and mixed into the composting feedstocks.
Waim weather enhances water loss from compost windrows by surface evaporation. Increased
turning also results in a higher evaporation rate. This can be an advantage if a drier compost is
desired, but if the evaporation rate becomes too high, water should be added to reduce potential
fire hazards.
Periods of high rainfall can also be a problem for windrow composting. Windrows usually
absorb water from normal rainfall or snow without saturating the materials. If the windrows
become wetter than desired, more turnings are required to evaporate the added moisture. Rain
can also produce muddy conditions, making it difficult to operate turning equipment. Snow can
halt operation altogether until plowed from equipment paths. In addition, puddles and standing
water can lead to anaerobic conditions at the base of a windrow. It is important that the .
composting site has adequate drainage to compensate for periods of high rainfall.
Table 8-18. Desired Characteristics of Raw Material Mixes
Characteristic
Caibon to Nitrogen (C:N) Ratio
Moisture Content
PH
Bulk Density Qbs/y3)
Reasonable Range
20:1-40:1
40-65 percent
5.5-9
Less than 1,100
Preferred Range
25:1-30:1
50-60percent
6.5-8.5
No preferred range
Source: NREAS, 1992.
Carbon and nitrogen serve as nutrients for the microorganisms, and for efficient composting they
should be available in the right balance. A good C:N ratio falls between 25:1 and 35:1, although
recommendations vary based upon site-specific conditions. For example, a study by Virginia
Polytechnic Institute and State University concluded that the best combination of straw and raw
swine manure for composting has a C:N ratio of 16:1 and a moisture level of 50 to 70 percent
(Collins and Parson, 1993). Above the optimum range of C:N ratio, the materials break down at a
slower rate, while a lower ratio results in excess nitrogen loss. For example, a study of poultry
litter composting as a function of the C:N ratio and the pH of the starting materials showed that
ammonia emissions decreased substantially as the C:N ratio increased through addition of short
paper fiber (C:N ratio(> 200:1) to broiler litter (Ekinci et al., 1998). As composting progresses,
the C:N ratio will fall gradually because the readily compostable carbon is metabolized by
microorganisms and the nitrogen is converted to nitrate and organic forms.
In animal manure, the C:N ratio is usually 10:1 to 15:1. The C:N ratios for different manures
vary: poultry litter 10:1, layer manure 5:1, cattle feedlot manure 13:1, dairy manure 18:1, swine
feedlot manure 3:1, and horse stable manure 25:1. Bulking materials can be added to increase
the C:N ratio in the compost pile. Typical bulking materials include grass clippings (C:N ratio of
12:1 to 25:1); hay (15:1 to 32:1); oak leaves (50:1); shrub and tree trimmings (50:1 to 70:1);
straw, comhusks, and cobs (50:1 to 100:1); pine needles (60:1 to 100:1); sawdust (150:1 to
700:1); wood chips (500:1 to 600:1); or newspaper (400:1.to ;850:1). For example, dairy manure
is a good substrate for composting because it breaks down quickly and supplies the
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microorganisms with most of the required nutrients, but it is also nitrogen-rich, excessively wet,
and has a carbon-to-nitrogen ratio ranging from 12:1 to 18:1. Moisture content varies from about
75 percent for manure collected from stanchion barns to about 85 percent from free-stall
operations, with the variability determined primarily by the amount of bedding used. To make
dairy manure more suitable for composting, it must be mixed with bulking agents that can be
easily incorporated into the composting mix by using them as bedding.
The feasibility of using sawdust and chopped fescue hay as a low-cost waste carbon source to
compost with separated swine manure solids was investigated using 21-liter vessels and bin
composting units (Hoehne et al, 1998). Manure and fescue hay produced the lowest C:N ratio in
bom small and large composting units. Temperature trends were used to indicate biological
activity. Composting manure with a carbon source was recommended because the product was
easy to transport, appropriate for transport through residential areas, and odor-stable, even though
composting is labor intensive.
The rate of air exchange and effectiveness of aeration of windrows depends on the porosity of
the windrow. For example, a wet, dense windrow containing manure is less porous than a
windrow of leaves. Windrows that are too large may result in anaerobic zones occurring near the
center and causing odors when the windrow is turned. Periodic turning of window compost piles
exposes the decomposing material to the air and keeps temperatures from getting too high
(exceeding 170 °F). The most important effect of turning is rebuilding the windrow's porosity.
Turning fluffs up the windrow and restores pore spaces lost from decomposition and settling,
thereby restoring oxygen within the pore spaces for microorganisms and improving passive air
exchange. Turning also exchanges the material at the surface with material in the interior. The
materials compost evenly and, as a result, more weed seeds, pathogens, and fly larvae are
destroyed by the high temperatures. The minimum turning frequency varies from 2 to 10 days,
depending on the type of mix, volume, and ambient air temperature. As the compost ages, the'
frequency of turning can be reduced.
A study in Ohio measured ammonia concentrations from dairy manure and rice hulls composted
with various aeration rates (Hong et al., 1997). Temperature and ammonia concentrations
peaked 48 days after aeration begins and then declined steadily, leveling off after 150 hours. The
effect of intermittent aeration on composting swine waste was studied to determine changes in
ammonia emissions and dry matter loss (Hong et al., 1998). Continuous and intermittent
aeration treatments were tested on composting hog manure amended with sawdust in pilot-scale
200-liter vessels. Ammonia emissions were 39 percent lower from the intermittent aeration
treatments, and nitrogen losses as NH3-N were 26 percent lower for continuous aeration and 14
percent lower for intermittent aeration. Dry solids loss and other physicochemical properties
were similar between the two treatments. It was concluded that intermittent aeration may be a
practical method of reducing nitrogen loss and ammonia emissions when composting swine
manure with sawdust.
Smaller particle size provides greater surface area and more access for the degrading organisms
It may be necessary to reduce by grinding the particle size of some material such as corn stalks.
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Windrow turning blends raw materials and breaks up particles into smaller pieces, thus
accelerating biodegredation through increased surface area.
Heat produced during the composting process raises the temperature of the composting
materials. Because the heat produced is directly related to the biological activity, temperature is
the primary gauge of the composting process. During the first few days of composting, pile
temperatures increase to between 104 and 158°F. This range enhances the growth and activity
of the microorganisms. In addition, temperatures above 131 ° F kill most pathogens, fly larvae,
and weed seeds. The high temperature might be maintained for several days, until the
microorganisms begin to deplete their food source or until moisture conditions become less than
optimal. Mixing the composting feedstock brings more undecomposed food into contact with
the microorganisms, replenishing their energy supply: Once the optimum moisture level is
restored and the feedstocks have been remixed, the temperature increases again. After the.readily
decomposable material is depleted, the compost pile no longer heats upon remixing. The
temperature continues to drop to ambient, and only very slow decomposition continues.
Although composting can be accomplished year-round, seasonal and weather variations often
require operational adjustments. This is especially true for windrow composting. Cold weather
can slow the composting process by increasing the heat loss from piles and windrows. The lower
temperatures reduce the microbial activity, which decreases the amount of heat generated. To
compensate for cold weather, windrows should be large enough to generate more heat than they
lose to the environment, but not so large that the materials become excessively compacted.
Windrows that are too small can lose heat quickly and may not achieve temperatures high enough
to cause moisture to evaporate and kill pathogens and weed seeds. ...
Demonstration Status: Agricultural composting is experiencing a resurgence of activity,
particularly in the northeastern United States. A growing number of farmers are now composting
significant quantities of organic materials. These fanners have incorporated composting of a
wide variety of organic wastes generated on and off farm into their normal operations. Some
own large commercial enterprises; others are small "hobby" farms. A number operate otherwise
traditional dairy enterprises, and several are organic vegetable growers. Some use all or most of
the finished compost on the farm, and some produce compost and soil mixes as a primary
agricultural product. Many use existing on-farm technology to manage the compost piles, and
others have invested in specialized compost production equipment.
Several Massachusetts dairy farms have adopted composting as a manure management technique.
In a study of five farms practicing composting in that state, it was found that three used the
windrow method of composting, one used the passive method, and one experimented with
several composting methods, finding the windrow method the most successful (Rynk, 2000).
The Rosenholm-Wolfe Dairy farm in Buffalo County, Wisconsin, has successfully produced
compost for the commercial market using organic solids separated from manure that had been
flushed from a 250-head free-stall barn (Rosenow and Tiry, ). The raw composting
material has a C:N ratio of .30:1 and a moisture content of 60 percent, which is ideal for rapid
production of a high-quality product using windrow composting.
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A pilot project conducted at the Purdue Animal Science Research Center has shown that
composting can be an efficient way to manage waste from dairy farms, hog farms, beef feedlots,
and poultry operations at a lower cost than that associated with other waste management methods
(Purdue News, August 1998). The composting site has 13 rows of compost material, of them
each 5 feet tall, 10 feet wide, and 250 feet long. The rows are turned using a specialized
windrow turner.
Three fundamental factors driving this renewed interest in composting are environmental and
community constraints on traditional manure management options, increased understanding of
the agronomic benefits of compost use, and rising disposal costs for such materials as municipal
yard waste and food processing wastes, which might be managed for a profit in an agricultural
setting. Despite growing interest, however, the environmental and possible economical benefits
of composting are challenged by a variety of constraints. An agricultural composting study
conducted by Cornell University (Fabian, 1993) concluded that governmental agencies need to
take a number of steps to farther encourage agricultural composting, including minimizing
regulatory constraints on farm-composted materials, encouraging local zoning to allow compost
facilities as a normal agricultural operation, providing governmental assistance for composting
equipment and site preparation, developing procurement guidelines for state agencies to use
compost in preference to peat and topsoil, and supporting research and demonstration programs
that explore new applications for compost in the agricultural sector.
Practice: Dehydration and Pelleting
Description: Dehydration is the process by which the moisture content of manure is reduced to a
level that allows the waste to be used as a commercial product, such as fertilizer for horticulture.
Applicability and Performance: Dehydration has been used on a variety of animal waste
products, including poultry manure and litter. The output material (dried to about 10 percent
moisture content) is an odorless, fine, granular material. With a moisture content of from 10
percent to 15 percent, a slight odor may be noted. Crude protein levels of from 17 percent to 50
percent have been reported in dried poultry waste (USEPA, 1974). The material can also be
formed into pellets prior to drying. Pelleting can make the material easier to. package and use as
a commercial fertilizer.
Operational Factors: Manure is collected and dried from an initial moisture content of about 75
percent to a moisture content of from 10 percent to 15 percent. The drying process is usually
accomplished using a commercial drier. The input requirement for most commercial driers is
that the raw material be mixed with previously dried material to reduce the average moisture
content of the input mixture to less than 40 percent water.
The mixture is fed into a hammer mill, where it is pulverized and injected into the drier. An
afterburner is generally incorporated to control offensive odors. The resultant dried material is
either stockpiled or bagged, depending on the ultimate method of disposal selected. Units
reported range in size from small portable units to systems capable of processing 150 000 tons
per year (USEPA, 1974).
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Advantages and Limitations: The drying of animal waste is a practiced, commercial technology
with the dehydrated product sold as fertilizer, primarily to the garden trade. It is an expensive
process that can be economical only where the market for the product exists at the price level
necessary to support the process.
Development Status: The status of dehydrating animal manure is well established. Full-scale
drying operations have been established with animal manure, in some cases since the late 1960s.
A number of manufacturers offer a line of dehydration equipment specifically designed for this
purpose. At least one large-scale facility, currently under construction on the Delmarva
Pennisula, will be used to treat broiler manure.
Practice: Centralized Incineration of Poultry Waste
Description: Centralized incineration is an alternative method of disposing of excess poultry , ,
litter. Most poultry litter has energy content and combustion qualities similar to those of other
biomass and commercially used alternative fuels (e.g., wood and refuse-derived fuels from
municipal trash). Under a centralized incineration approach, poultry litter that is removed from
the houses is collected and transported to a centralized facility that has been designed or
retrofitted to burn poultry litter. The concentration of the poultry industry in several areas of the
country and the dry composition of the manure facilitates litter transport, which is critical to the
success of this alternative treatment technology. The centralized incineration unit could be
located at a processing plant to provide power to the plant or at a stand-alone facility that would
generate power for public use.
Application and Performance: Most of the nutrients in the litter would not be destroyed by
combustion, but would be captured in the combustion ash and could be managed safely and ,
economically: Consequently, the most immediate environmental benefit from burning litter is
that its nutrients would not be applied to cropland and therefore would not run off into
waterways.
Advantages and Limitations: The incineration of poultry litter to generate energy offers several
clear advantages over current practices. The energy recovered by burning poultry litter would
displace conventional fossil fuels and thereby avoid greenhouse gas emissions. The pollution
control equipment required for major fuel burning units would likely minimize other combustion
emissions when the manure is burned. •
»
Limitations of using poultry litter as fuel include variability in litter composition, litter
production rates, and litter caloric content. One of the most important detenninants of the
suitability of any substance as a fuel is its moisture content, and there is no guarantee that litter
would undergo any sort of drying process prior to combustion. Moisture in a fuel represents a
reduction in its heating value because some of its energy content must be used to vaporize the
moisture, reducing the fuel's effective energy output. Poultry litter has a much lower British
thermal unit (Btu) content, higher moisture content, and higher ash content than conventional.
fuels. It can pose greater operational problems (such as corrosion) and would probably be
convertible to steam at a lower efficiency than conventional fuels. Moreover, because of its
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much higher ash content, litter will yield far more unbumed residuals than other fuels. Metals, P,
and K from the litter will concentrate in the residual ash; however, bottom ash and fly ash can be
sold as fertilizer, contributing to the profitability of the technology.
Metals (e.g., copper, arsenic, zinc) may be present in litter because they are added to poultry feed
as a dietary supplement. Other metals may be unintentionally present in feed and bedding, or
may be scraped from the floor of a poultry house when the litter is removed. Aluminum may be
found in litter because alum is added to limit ammonia volatilization, and aluminum sulfate is
added to bind the P in litter, reducing P in runoff when applied to land. Metals in poultry litter
can affect its suitability for combustion in several ways. First, the concentration of metals could
affect the nature of air emissions from a poultry-fired boiler. Second, metals might pose a
problem in the ash created from litter combustion. Most toxic metals concentrate significantly in
combustion ash relative to the unbumed litter.
Although litter combustion has significant environmental advantages, adverse environmental
impacts might result from using poultry litter as a fuel source. Air emissions and treatment
residuals result from the incineration of any fuel, however, and the chemical and physical
properties of litter as a fuel do not suggest that burning litter would result in significantly worse
pollution emissions than would burning conventional fuels. When compared with the
combustion of conventional fuels, combustion of poultry litter produces fewer tons of nitrogen
oxides (NOJ, sulfur oxides (SOJ, and filterable particulate matter (PM) emissions at the boiler
than coal or residual (No. 6) oil. In comparison with distillate fuel oil, litter has a less desirable
emissions profile. A comparison with wood is mixed; litter shows lower emissions of carbon
monoxide (CO), filterable PM, and methane, whereas wood shows lower emissions of NOX, SOX,
and carbon dioxide (CO^. Despite the high N content of poultry litter, burning litter should not
increase NOX emissions. NOX emissions from combustion primarily depend on the nature of the
combustion process itself (affecting the degree to which atmospheric nitrogen is oxidized) and
only secondarily on the amount of N in the fuel. In fact, the high ammonia levels in poultry litter
may act to reduce much of the NOX that is formed during combustion back into elemental N.
This is the reaction that underlies most of the modern NOX control technologies (selective
catalytic and noncatalytic reduction) used in utility boilers.
SOX formation in combustion processes depends directly on the sulfur content of the fuel.
Therefore, SOX emissions from burning poultry litter should be lower than those from high-sulfur
fuels (residual oil or higher-sulfur coal) and higher than those from low-sulfur fuels (distillate oil,
low-sulfur coal, wood, natural gas). The relatively high alkali (potassium and sodium) content of
litter and litter combustion ash may cause problems in the combustion system: a low ash melting
point, which can lead to slagging and deposition of "sticky" ash on combustion surfaces, and
high particulate emissions in the form of volatile alkali compounds. However, this high alkali
ash content also has the likely benefit of reducing SOX in the flue gas through a "scrubbing"
effect. If the uncontrolled emissions from burning poultry litter appear likely to exceed emission
standards, an appropriate air pollution control device would be installed at the unit, just as it
would be at a conventional fuel-burning unit.
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Costs for this technology include cleanout and storage/drying costs, as well as the cost of
transporting the litter to the incineration facility. A fuel user might hire a contractor to remove
litter from a poultry house and load it onto a truck for delivery, hire a contractor to load the litter
and pay a grower for the litter and cleanout, or hire a contractor to get the litter from the shed, and
load it onto a truck, paying the grower for the litter, cleanout, and storage. In addition, fuel users
may also need to install new fuel-handling and management equipment and perform some
redesign of the combustion process. Burning litter effectively might entail new plant
construction, such as construction of a direct-fired biomass facility, retrofitting of an existing
plant for direct firing poultry litter, or retrofitting of an existing cogeneration facility or boiler to
co-fire poultry litter with conventional fuels (such as oil or coal). Most operations would also
require a storage structure and litter supply system. The costs of retrofitting a processing plant
boiler or feed mill boiler to co-fire litter do not appear excessive. The cost savings from burning
litter would continue indefinitely and would increase as fuel users find more effective and
efficient ways of burning litter.
Operational Factors: One of the first steps in using poultry litter as a fuel is to estimate the
amount of litter produced by a feedlot. This amount is then compared with the quantity of litter
that could be spread appropriately on local cropland to meet agricultural nutrient needs. The '
amount by which litter production exceeds the litter needed for crop nutrient purposes is the
measure of the amount available for fueL Several approaches are in use to project the volume of
litter that a poultry operation will generate. The differing results of these approaches are mostly a
function of the wide range of variables that affect poultry litter production—type of bird, feed
and watering programs, bird target weight, type of bedding, litter treatment for ammonia control,
house type, crusting procedures, and cleanout schedules. One method uses a calculation of 10.8
Ib of manure produced per broiler per year, another assumes an average of 35 Ib of manure per
1,000 birds per day, and another assumes an average of 2.2 Ib of litter per bird. Other more
sophisticated methods apply a rate of litter produced per unit of bird weight produced. However,
the most straightforward and commonly used calculation relies on an assumption of 1 ton of litter
per 1,000 birds. It should be noted that since a significant portion of the weight of litter is water,
having drier litter means fewer tons per bird. Therefore, the 1 ton of litter per 1,000 birds
assumption should be treated strictly as a rough estimate.
The most important characteristic of litter with regard to its value as a fuel is its caloric content.
Although the energy content of litter varies significantly, there is less variation after it is air-dried
or oven-dried. For example, research conducted on the Btu content of several Utter samples
under varying moisture conditions showed that litter with a moisture content ranging from 0
percent to 30 percent having a caloric content ranging from 7,600 Btu per pound to 4,700 Btu per
pound, respectively. Litter has a much lower caloric value than conventional fuels, but it has an
energy content similar to that of several other commonly used alternative fuels. In addition,
when litter is used as a fuel, its density affects the nature of the fuel feed systems and boiler
configurations required. The density of litter also affects how the litter can be stored, handled,
transported, and land-applied. Estimates of litter density vary widely, depending largely on the
moisture content of the litter. Estimates range from 19 to 40 pounds per ft3, with the average
being roughly 30 pounds per ft3.
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Because poultry litter is quite Variable with respect to several characteristics important to its use
as a fuel, the fuel user must develop quality control and quality assurance guidelines to ensure
that the litter is of consistent quality and well suited for combustion. Criteria for accepting litter
may include acquiring only litter that has been covered in storage for some period of time to
avoid excessive moisture and increase Btu content per ton, or mixing a large quantity of litter on
site prior to burning to reduce fluctuations in quality across individual loads of litter. One plant
in operation in the United Kingdom employs the following measures: (1) litter shipments are
examined for moisture content with infrared equipment, and shipments with excessive moisture
are rejected; (2) core samples are taken and analyzed for moisture, ash, and Btu content; (3)
based on the results of the analysis, the load is sorted into one of several storage pits; and (4) an
overhead crane draws from the different storage pits in a manner providing an appropriate blend
of wet and dry material, giving a reasonably constant caloric value when fed to the furnace.
Demonstration Status: This technology is not currently used in the United States for poultry
waste; however, existing boilers could be retrofitted to co-fire litter with conventional fuels such
as oil or coal, or litter could be burned in a direct-fired biomass facility to generate electricity,
steam, or heat at power plants or in boilers at poultry processing plants to supplement energy'
needs. Other agricultural and silvicultural wastes such as bagasse, almond shells, rice hulls, and
wood wastes are burned for energy recovery in scattered utility and industrial plants in the United
States. In the United Kingdom, several medium-sized, profitable electric power plants are fueled
by poultry litter. This indicates that centralized incineration of poultry waste has the potential to
develop into a commercially viable alternative treatment technology for poultry growers.
A British company, Fibrowatt, conceived of, developed, and operates the electricity plants hi the
United Kingdom that use poultry litter as fuel. Fibrowatt's three plants (two operating, one under
construction) are all new and are all electricity-generating plants rather than industrial boilers for
steam heat or cogeneration facilities. Fibrowatt's litter storage and handling system is
proprietary. The Fibrowatt plant at Eye in Suffolk, the first plant fueled by poultry litter, came on
line in July 1992. The second plant, hi Glanford at Humberside, came on line in November
1993. The third and largest plant is at Thetford hi Norfolk, which was scheduled to begin
operations in 1998.
' »
The basic operations at the three plants are similar. Each plant is situated hi the heart of a
poultry-producing region. Trucks designed to rninimize odor and the risk of biocontamination
transport the litter from farms to the power plants. The trucks enter an "antechamber" to the
litter storage structure, and the doors of the antechamber are closed before the track unloads.
Upon arrival, the litter is sampled for nearly 40 different traits, including Btu content and
moisture. The litter is .stored and conditioned hi a way that homogenizes the fuel. It is kept
under negative pressure to control odor, and the ah- from the fans in the storage structure is
directed to the boilers and used hi combustion.- The Glanford plant uses Detroit Air-jet spreader-
stokers (reciprocating grate, solid-fuel combustors) to burn fuel. The Eye plant employs a
stepped grate stoker. The boilers are Aalborg Ciserv three-pass, natural-circulation, single-drum
water tube boilers. There are modifications to the ash removal process because the high alkali
content of the litter can cause corrosion hi the boiler. The steam from the boiler is passed to a
turbo-alternator, and electricity is sold to the grid. The Fibrowatt plants are commercially viable
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in the United Kingdom because the prices Fibrowatt can charge for the electricity delivered to the
grid are far higher than the prices charged in the United States. In addition, farmers are charged a
disposal fee for their litter, and Fibrowatt is able to earn money on the ash produced by
combustion, which the plants collect and sell as concentrated fertilizer with a guarantee analysis.
Theoretically, the process could be replicated in the United States, but a full-market study would
be needed.
Poultry litter is not currently used.as fuel in the United States; however, research into the
feasibility of burning Utter for electricity, steam, or heat is under way. Maryland Environmental
Services (MES) has asked the Power Plant Research Program (PPRP), an arm of the Maryland
Department of Natural Resources, to help investigate the possibility of burning poultry litter at
the cogeneration plant at the Eastern Correctional Institute. In February 1998, Exeter Associates
published a report for MES projecting the costs of various scenarios for using poultry litter at the
plant. One of the recommendations in the report was that a full engineering study be done to
obtain a better estimate of the costs involved. MES submitted a request for proposals on this
basis in April 1998 and received bids from several companies. Among the companies that bid
were Fibrowatt and two companies that build gasifiers. As of July 1998, the gasifier company
bids had been rejected and the remaining bids were still under consideration. MES is determined
to rum the cogeneration plant at the Eastern Correctional Institute mto a working facility and is
interested in a Fibrowatt-style system, the technology of which is proven and currently
operational.
Other Technologies for the Treatment of Animal Wastes
Practice: Aquatic Plant Covered Lagoons
Aquatic plant covered lagoons provide low cost wastewater treatment by removing suspended
solids, BOD, N, and P in structures that are mechanically simple, relatively inexpensive to build,
and low in energy and maintenance requirements (WPCF-TPCTF, 1990). Wastewater treatment
occurs through a combination of mechanisms including biochemical conversion through plant-
microbial reactions, plant uptake, settling, volatilization, and adsorption onto sediments. Free-
floating aquatic plants such as duckweed (Lemnaceae) and water hyacinth (Eichhornia crassipes)
grow rapidly (in a matter of days) and take up large amounts of nutrients from wastewaters
(Reddy and De Busk, 1985). In addition, the extensive root system of water hyacinth provides a
large surface area for microbial growth, which promotes degradation of organic matter and
microbial transformation of N (Brix, 1993). Greater than 70 percent removal of pollutants by
aquatic plant covered lagoons has been reported for domestic wastewater treatment (Orth and
Sapkota, 1988; Alaerts et al., 1995; Vermaat and Hanif, 1998). Depending on the lagoon design,
water depth, and retention time, effluent from hyacinth and duckweed covered lagoons can
potentially meet secondary and sometimes advanced wastewater discharge standards for BOD,
suspended solids, N, and P (Buddhavarapu and Hancock, 1991; Bedell and Westbrook, 1997).
In addition to providing wastewater treatment, nutrient uptake by water hyacinth and duckweed
produces a protein rich biomass (Reddy and Sutton, 1984; Oron et al., 1988) that"can be
harvested and used as an agricultural fertilizer or a feed supplement (Oron, 1990). Furthermore,
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duckweed and hyacinths provide a dense cover that restricts algal growth by impeding sunlight at
the water surface (Brix, 1993), reduces odor by preventing gaseous exchange, and acts as a
physical barrier to" reduce the breeding of mosquitoes (Buddhavarapu and Hancock, 1991).
Limitations of aquatic plant covered lagoons include a need for large treatment areas,
pretreatment of wastewater in settling ponds, and floating grid barriers to keep plants from
drifting (Brix, 1993). Cold temperature reduces the growth rate of floating plants (Brix, 1993).
Although duckweed removes fewer nutrients than do water hyacinths (Reddy and De Busk,
1985), duckweed has higher protein and lower fiber, a faster growth rate, and lower harvesting
costs (Oron, 1990), and can grow at temperatures as low as 1 to 3°C (Brix, 1993). Duckweed
prefers ammonia over nitrate (Monselise and Kost, 1993), transforms nutrients to a protein-rich
(25-30 percent) biomass (Oron, 1990), and selected duckweed species (Lemnagibba, Lemna
minor) have been demonstrated to grow on undiluted swine lagoon effluent (Bergmann et al.,
2000). For these reasons, duckweed is potentially effective in the treatment of animal waste.'
Further studies are needed to understand better the application and performance of aquatic plant
covered lagoons for animal waste treatment.
Practice: Nitrification -Denitrification Systems—Encapsulated Nitrifiers
Description: Nitrification-denitrification refers to the biological conversion of ammonium first
to nitrate, then to nitrogen gas. Many schemes for nitrification-denitrification have been
researched, including the use of nitrifying bacteria encapsulated in polymer resin pellets to speed
up the reaction (Vanotti and Hunt, 1998). The theory is that elevated populations of nitrifying
bacteria immobilized on resin pellets that are retained in a treatment system will convert more
ammonia to nitrate faster than free swimming bacteria. There is. ample evidence that attached
media systems that retain bacteria on their surface remove the target pollutants more effectively
than bacteria that have to swim to their food and can be washed from the system.
Vanotti and Hunt demonstrated in the lab that an enriched solution of encapsulated nitrifiers in
an oxygen-saturated solution at 30 °C, with 150 ppm BOD and 250 ppm TKN, could nitrify 90
percent of the ammonia in a batch if sufficient alkalinity was added. The research also
documented that a solution with encapsulated nitrifiers had more and faster nitrification than an
aerated equivalent volume of anaerobic lagoon effluent with no nitrifiers added.
A pilot plant using imported pellets operating on anaerobic lagoon effluent followed the
laboratory work. The effluent was first screened, and then introduced into a contact aeration
treatment to reduce BOD. The aeration sludge was settled next, and then treated effluent was
introduced into a nitrification tank hi which another aeration blower was used to maintain a
dissolved oxygen concentration of 3 milligrams per liter. The pH was maintained at 7.8 or
greater with sodium hydroxide as necessary. The results of 3 months of operation were that,
given adequate pretreatment, high nitrification rates of swine wastewater could be attained using
enriched nitrifying populations immobilized on polymer resins.
Application and Performance: The technology specifically targets nitrification of ammonia, and
could reduce the loss of ammonia-N to the atmosphere. When set up and operated properly, the
treatment can convert 90 percent of the ammonia-N remaining in pretreated lagoon effluent to
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nitrate. A nitrified farm effluent can be denitrified easily by either returning it to an anaerobic
environment resulting in release of nitrogen gas (N2). This technology will have little if any
effect on pathogens, metals, growth hormones, or antibiotics. It can be assumed that most of
these constituents were removed in the process of aerating the manure to reach oxygen-saturated
conditions, which would enable the encapsulated nitrifiers to function.
Advantages and Limitations: A facility to support this process would be expensive to build,
operate, and maintain. It is difficult to imagine this process being used on a farm. One area not
considered is the sludge generated by aerobic pretreatment. Another limitation is the anaerobic
lagoon pretreatment step used to reduce initial BOD and limit sludge production.
Operational Factors: Nitrifying bacteria are temperature sensitive, but the effect of temperature
was not discussed by Vanotti. Rainfall and varying concentration should not affect performance;
however, seasonal temperature variation may reduce nitrification.
Demonstration Status: North Carolina State University has operated a pilot plant in Duplin
County, North Carolina.
Disinfection—Ozonation and UV Radiation
Ozonation is commonly used to disinfect wastewater after biological treatment. Ozone is a
highly effective germicide against a wide range of pathogenic organisms, including bacteria,
protozoa, and viruses. It oxidizes a wide range of organics, can destroy cyanide wastes and
phenolic compounds, and is faster-acting than most disinfectants. Moreover, unlike chlorine,
ozone does not generate toxic ions in the oxidation process.
UV radiation is used primarily as a disinfectant. It inactivates organisms by causing a
photochemical reaction that alters molecular components essential to cell function. It is very
effective against bacteria and viruses at low dosages and produces minimal disinfection by-
products. To enhance the inactivation of larger protozoa, UV radiation is often considered in
conjunction with ozone.
Disinfection measures such as ozonation and UV radiation are not commonly practiced in the
United States for treatment of animal wastes. Animal wastewater would require primary and/or
biological treatment prior to disinfection. Ozone is generally effective for aqueous waste streams
with less then 1 percent organic content. Both processes are costly and require higher levels of
maintenance and operator skill. Wastewater with high concentrations or iron, calcium, turbidity,
and phenols may not be appropriate for UV disinfection. The effectiveness of UV disinfection is
greatly hindered by high levels of suspended solids.
Vermicomposting
Composting is the controlled decomposition of organic materials and involves both physical and
chemical processes (see Composting—Aerobic Treatment of Solids). During decomposition,
organic materials are broken down through the activities of various invertebrates that naturally
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appear in compost, such as mites, millipedes, beetles, sowbugs, earwigs, earthworms, slugs, and
snails. Vermicomposting is accomplished by adding worms to enhance the decomposition
process. •
Vermicomposting uses "redworms" (Eisenia foetida), which perform best at temperatures
between 50 and 70 °E. .Bones, meats, fish, or oily-fats should not be added to a worm compost
box because of odors and rodent problems they could create. Successful operation requires a
great amount of maintenance because the worms are highly sensitive to alterations in oxygen
levels, temperature, moisture, pH, nutrients, and feed composition and volume. Heavy metals are
not treated by any means of composting and can be toxic to the microorganisms and invertebrate
population.
Farm-scale systems for Vermicomposting have been developed. They tend to be simple systems
using conventional material-handling equipment. Labor and equipment are required to add
material to the bed, remove composted material, separate the compost from the worms by
screening, and process the compost and worms for their respective markets (the compost as a
protein additive to animal feed; the worms as fish bait). Flies are a potential problem since this
process occurs at a lower temperature than the general composting process. Pathogen destruction
and drying are also reduced. A drying or heating step may be required to produce the desired
compost.
Chemical Amendments
Chemical amendments to poultry litter have been proven to enhance nutrient removal and odor
elimination. Ammonia volatilization from poultry litter often causes high levels of atmospheric
ammonia in poultry houses, which is detrimental to both farm workers and birds. Ammonia
emissions from houses can also result in a loss of fertilizer nitrogen and aggravate environmental
problems such as acid rain. Litter amendments, such as aluminum sulfate (alum), ferrous sulfate,
and phosphoric acid, have been proven to reduce ammonia volatilization from litter dramatically.'
Alum has also been shown to reduce water-soluble P concentrations in litter (whereas phosphoric
acid greatly increases water-soluble P levels) and alum has the ability to reduce the solubility of
metals (arsenic, copper, iron, and zinc), thereby reducing metal concentrations in rainwater
runoff. Ferrous sulfate is also effective in reducing soluble P in the runoff from land-applied
poultry litter, but is not favored as an option for use inside poultry houses because chickens
might ingest the toxic substance.
Odor control is a major concern at many CAFOs. Chemical additives such as potassium
permanganate have been used to reduce levels of sulfides, mercaptans, and other odor-causing
agents in manure storage structures, particularly lagoons. Large amounts of lime are often added
to wastewaters (raising the pH>10) to eliminate odor by reducing microbial activity. Hydrogen
peroxide is applied to liquid manure to control sulfides during waste removal and land spreading.
Zeolite (a volcanic mineral),.cement kirn, and power-plant alkaline by-products are frequently
used to reduce volatilization and odors.
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Gasification
The fuel produced by gasification is viewed today as an alternative to conventional fuel. A
gasification system consists of a gasifier unit, purification system, and energy converters (burners
or internal combustion engine). The gasification process thermochemically converts biomass
materials (e.g., wood, crop residues, solid waste, animal waste, sewage, food processing waste)
into a producer gas containing carbon dioxide, hydrogen, methane and some other inert gases.
Mixed with air, the producer gas can be used in gasoline and diesel engines with little
modification.
Gasification is a complex process best described in stages: drying, pyrolysis, oxidation, and
reduction. Biomass fuels have moisture contents ranging from 5 to 35 percent. For efficient
operation of a gasification system, the biomass moisture content must be reduced to less than 1
percent. The second stage of the process,'pyrolysis, involves the thermal decomposition of the
dried biomass fuels in the absence of oxygen. The next stage, oxidation, produces carbon
dioxide and steam. The last stage, reduction, produces methane and residual ash and unburned
carbon (char).
Gasification is one of the cleanest, most efficient combustion methods known. It eliminates
dependence on fossil fuel and reduces waste dumping. It extracts many substances, such as
sulfur and heavy metals, in elemental form. Factors limiting tihe use of this process include
stringent feed size and materials handling requirements. Process efficiency is strongly influenced
by the physical properties of the biomass (surface, size, and shape), as well as by moisture
content, volatile matter, and carbon content (see Pyrolysis below for additional limitations).
Gasification of animal wastes is still hi the developmental stages. It is currently considered a
better alternative to incineration for its lower NOX emissions. However, this treatment option is
limited to the animal feed operations that have a market hi which to sell the excess power or heat
generated by the gasification unit. Without this advantage, such facilities would be inclined to
resort to less expensive waste treatment technologies.
Pyrolysis
Pyrolysis is a major part of the gasification process described above. It is formally defined as
chemical decomposition induced hi organic material by heat hi the absence of oxygen. Pyrolysis
transforms organic materials into gaseous components, small quantities of liquid, and a solid
residue (coke or char) containing fixed carbon and ash. Pyrolysis of organic materials produces
combustible gases, including carbon monoxide, hydrogen and methane, and other hydrocarbons.
If the off-gases are cooled, liquids condense, producing an oil/tar residue and contaminated
water.
Target contaminant groups for pyrolysis are volatile organic compounds and pesticides. The
process is applicable for the separation of organics from refinery wastes, coal tar wastes,
wood-treating wastes, creosote-contaminated soils, hydrocarbon-contaminated soils, mixed
(radioactive and hazardous) wastes, synthetic rubber processing wastes, and paint waste.
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Economic factors have limited the applicability of pyfBlysis to the animal waste management
field. There are also a number of handling factors that limit applicability. Pyrolysis involves
specific feed size and materials handling requirements. The technology requires that the biomass
be dried to low moisture content (<1 percent). Slight inconsistencies in moisture content and
biomass properties (both physical and chemical) greatly increase operational costs. These
considerations make it difficult to apply this technology to animal waste. Pyrolysis is not
effective in either destroying or physically separating inorganics from the contaminated medium.
Volatile metals may be removed as a result of the higher temperatures associated with the
process but are not destroyed. Biomass containing heavy metals may require stabilization.
Pyrolysis is still an emerging technology. Although the basic concepts of the process have been
validated, the performance data for this technology have not been validated according to methods
approved by EPA and adhering to EPA quality assurance/quality control standards. Site
characterization and treatability studies are essential for further refining and screening of this
process. Pyrolysis has been considered for animal waste treatment as part of the gasification
technology, but is currently not in high demand because of operation and maintenance costs.
•i>
Freeze Drying and Freeze Crystallization or Snowmaking
Freeze drying involves freezing the waste, which causes the solids and liquids to separate. When
the frozen sludge melts, the liquid is easily drained away for reprocessing. The remaining sludge
is high in solids, completely stabilizedrand capable of being spread on land with conventional
agricultural equipment. The process has proven to lower waste management costs by reducing
waste volume., ._
Freeze crystallization, or snowmaking, is a treatment process in which wastewater is turned to
snow, thus readily stripping volatile gases from water. Other contaminants are precipitated from
the water in a process called atomizing freeze-crystallization. Meltwaters may have a nutrient
reduction of up to 60 percent, with almost 100 percent of pathogens killed (MacAlpine, 1997).
Both processes are scarcely utilized due to applicability limitations. These processes are suited
only to colder climates. The freeze drying process requires significant storage capacity, and
facilities must be capable of storing up to 1 year's production of sludge on site.
Practice: Photosynthetic Purification
A proprietary new animal waste treatment technology, Photosynthetic Purification, uses the
nutrients in concentrated animal waste to grow algae and photosynthetic bacteria that yield a
harvestable crop (Biotechna, 1998). Photosynthetic Purification technology is reported to treat
high-strength, high-moisture waste streams with mirumal loss of manure nutrients and generate a
clean effluent that can be recycled or safely discharged. The resultant biomass can be used as a
high protein animal feed supplement. Nutritional value of the biomass is at least equivalent to
that of soy protein. Along with producing a valuable biomass, the main advantage of this
technology is that it reduces the potential environmental impact of land application or discharge
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of animal waste in regions with, concentrated animal feeding operations. A possible disadvantage
is that animal waste will need to be transported to a processing facility.
The technology has been under development by Biotechna Environmental (2000) Corporation
(BE2000) since the early 1990s. .Successful tests are reported to have been carried out at pilot
scale in Ireland (1994-95) and Connecticut, USA (1998). A laboratory-scale system and a full-
scale commercial demonstration plant are planned. Photosynthetic Purification produces high-
protein feed supplements and a range of other value added products for the feed and nonfood
markets. Because of proprietary information and patent pending status, little rnformation on this
technology is currently available to the public.
Deep Stacking of Poultry Litter
Research dating back to the 1960s (Bhattacharya and Fontenot, 1965) has shown that poultry
litter has significant nutritive value as a feedstuff for ruminants. Subsequently, concerns about
the potential public health impacts-of using poultry litter as well as other animal manures as
feedstuffs emerged. The presence and impact of pathogens, such as species of Salmonella and
Clostridium, in manures being used as feedstuffs was one of these concerns. There have been a
number of reports from foreign countries of botulism in animals fed diets containing animal
wastes (Fontenot et al., 1996).
For poultry litter, the response to this concern about potential pathogen transmission was the
development of the practice known as-deep or dry stacking-(MeGaskey, 1995). It consists simply
of piling litter in a conical pile or stack after it is removed from a poultry house and raises in
temperature to a maximum of 140 °F (60 °C) by microbes. Litter with a moisture content
exceeding 25 percent may reach temperatures above 140 °F if not covered to exclude air.
McCaskey et al. (1990) have shown that higher temperatures produce a material with a "charred"
appearance and reduced nutritive value. They reported that excessively heated litter has about 50
percent of the dry matter digestibility of litter that has not been excessively heated. This estimate
was based on the percentage of litter dry matter solubilized in rumen fluid after 48 hours. Also,
it was observed that the amount of N bound to acid detergent fiber and considered not available
approximately tripled in overheated Utter.
The practice of deep stacking of poultry litter enhances its value as a feedstuff for ruminants by
reducing concern about possible pathogen transmission. However, deep stacked poultry litter
cannot be considered pathogen-free because the stacked litter is not mixed out of concern that
reaeration will create the potential for excessive heating. Thus, outer regions of the deep stacked
litter might not reach the temperatures necessary for pathogen destruction. In reality, deep
stacking is composting in which oxygen availability limits the temperature and the degree to
which dry matter (volatile solids) are destroyed.
When deep stacking is done in a roofed structure such as a litter storage shed or in covered piles,
the potential water quality impacts are essentially nil; however, deep stacking in uncovered piles
creates the potential for leaching and runoff losses of nutrients, oxygen-demanding organics, and
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pathogens, as well as producing a feedstuff with reduced nutritive value. Because of the heat
generated, some ammonia volatilization is unavoidable, but is probably no greater than the losses
associated with land application. With proper management, odor is not a significant problem.
The impact of deep stacking on land application for litter disposal is a direct function of the
ability to market poultry litter as a feedstuff. If such a market exists, on-site land application
requirements are reduced or become unnecessary; however, the impact on a larger scale is less
clear. Although the utilization of litter N by ruminants can be relatively high, much of the litter P
consumed will probably be excreted. Thus, typical values for the P content of beef cattle manure
might not be appropriate for developing nutrient management plans for beef operations that feed
significant quantities of broiler litter. Also, total manure production by the beef cattle fed poultry
litter-amended rations may increase, depending on the dry matter digestibility and the ash content
of the litter fed (Martin et al., 1983).
As with the temporary storage of solid poultry manure in a dedicated structure, fire due to
spontaneous combustion is a risk associated with deep stacking of poultry litter. Thus, structure
design to exclude precipitation and routine monitoring of Utter temperature are important
operational factors.
Although reliable data regarding the extent of the use of deep stacking are unavailable, anecdotal
evidence indicates that the use of poultry Utter as a feedstuff for beef cattle is fairly extensive in
regions with significant broiler or turkey and beef cattle production. Thus, it appears reasonable
to assume that the use of deep stacking is also fairly extensive.
Practice: The Thermo Master™process
Thermo Tech™ Technologies, Inc., is a Canadian corporation in the business of converting food
wastes into a high-energy and high-protein animal feed supplement, and converting municipal
wastewater treatment sludges into a fertilizer material. The company has constructed several
organic waste conversion facilities, known as "Thermo Master™ Plants," that employ the
company's proprietary microbial organic waste digestion technology. The technology is
protected by U.S. and Canadian patents with patent applications pending in several other
countries.
The Thermo Master™ process was originally developed to create an animal feed supplement
from relatively high solids content food wastes such as fruit and vegetable processing wastes and
wastes of animal origin including meat, dairy, and fish processing wastes. Animal manures and
wastewater treatment sludges also were considered for conversion into a fertilizer material. The
process has been modified to enable processing of materials with a lower solids content
In the Thermo Master™ process, autoheated aerobic digestion is operated at the relatively short
residence tune of 30 hours to maximize single-cell protein production using the influent waste
material as substrate. The effluent from the digestion process is then dried and pelletized.
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The Thermo Master™ process could, in theory, be a viable method for poultry and swine carcass
disposal. In addition to recovering nutrients foruse as an animal feed supplement, the absence of
any pollutant discharges is an attractive characteristic of this process. Given that the process
operates at thermophilic temperatures, at least a two- to three-log 10 reduction in pathogen
densities should be realized (Martin, 1999). The process, however, has never been used for
animal carcass disposal.
As with rendering, the problems of preserving, collecting, and transporting carcasses could limit
use of this disposal alternative. A more significant limitation is the lack of any operating Thermo
Master™ plants in the United States. Only two plants are in operation as of April, 2000, and
they are both located.in Canada near Toronto, Ontario. A third, located near Vancouver, British
Columbia, is being rebuilt following a fire. Even if new plants were to be constructed in the
United States, it is likely that they would be located in or near major metropolitan areas given the
nature of the primary sources of process feedstocks. This would exacerbate the problem of
carcass transportation.
8.23.2 Mortality Management
Improper disposal of dead animals at AFOs can result in ground water contamination and health
risks. Most mortality management is accomplished through rendering of the dead animals.
Rendering involves heating carcass material to extract proteins, fats, and other animal
components to be used for meat, bone, and meal. Beef and dairy operations handle mortality
management almost exclusively through rendering operations. In most instances the rendering
operation will pick up the dead animals, resulting in no environmental JmpacU>n,the.operation-.._
For this reason, the remainder of this section focuses on swine and poultry mortality
management, and it will cover rendering, composting, and incineration.
Mortality Management: Swine
Large swine operations must dispose of significant numbers of dead pigs on a daily basis. For
example, a 1,000 sow farrow-to-wean operation with an average of 22 piglets per litter and a
pre-wean mortality rate of 12 percent will generate almost 16 tons of piglet carcasses per year,
assuming an average weight of 6 pounds per carcass. Assuming an average sow weight of 425
pounds and a sow mortality rate of 7 percent per year, the total carcass disposal requirement
increases to over 30 tons per year.
Improper disposal of swine carcasses can lead to surface or ground water contamination, or both,
as well as noxious odors and the potential for disease transmission by scavengers and vermin.
Historically, burial was the most common method of carcass disposal. Burial has been
prohibited in many states, largely because of concerns regarding ground water contamination.
The following subsections briefly describe and discuss the principal alternatives to burial for
swine carcass disposal: composting, incineration, and rendering.
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Practice: Composting - '..
Description: Composting is the controlled decomposition or stabilization of organic matter
(Gotaas, 1956). The process may be aerobic or anaerobic. If the composting mass is aerobic
and suitably insulated, the energy released in the oxidation of organic carbon to carbon dioxide
and water will produce a fairly rapid increase in the temperature of the composting mass. With
suitable insulation, thermophilic temperature levels will be reached. The higher temperature
increases the rate of microbial activity and results in quicker stabilization. Under anaerobic
conditions, the rate of biological heat production is lower because fermentation generates less
heat than oxidation, so the temperature increase in the composting mass is less rapid.
Thermophilic temperature levels can still be attained with suitable insulation; however, the rate
will be slower.
Application and Performance: Composting is a suitable method of carcass disposal for all swine
operations. The compost produced can be spread on site if adequate Land is available. Another
recently cited disposal option for-the compost is distribution or marketing as an organic fertilizer
material or soil amendment. Thorough curing to preclude development of odor or vermin
problems and screening to remove bones are necessary to make marketing a viable option.
Another requirement for composting as a method of swine carcass disposal is the availability of a
readily biodegradable source of organic carbon, such as sawdust, wood shavings, or straw.
When carcass composting is managed correctly, potential negative impacts on water and air
quality are essentially nonexistent, assuming proper disposal of the finished compost.
Mismanagement, however, can lead to seepage from the composting mass. This seepage has \
high concentrations of oxygen-demanding organics, N, and P; is a source of noxious odors; and
attracts vermin.
Advantages and Limitations: One of the advantages of swine carcass composting is the
relatively low capital cost of the necessary infrastructure. Depending on the volume of carcasses
generated daily, one or more of a series of two composting bins are required. These bins should
be located on a concrete pad in an open or partially enclosed shed-like structure. Critical to this
capital cost advantage is the availability of a skid-steer or tractor-mounted front-end loader for
handling materials. Federal and, in some instances, state cost sharing has been used to encourage
the construction and use of swine mortality composting facilities.
A recent comparison of carcass composting and incineration for disposal of poultry mortalities
suggests that the lower capital cost of carcass composting is offset by higher labor costs
(Wineland et al., 1998). The development of more fuel-efficient incinerators has made
incineration more cost competitive in recent years.
While the temperatures that can be attained in a mass of composting carcasses (130 to 150 °F)
will result in significant reductions in pathogen densities, finished swine mortality compost
cannot be considered pathogen-free. Therefore, appropriate biosecurity measures are necessary
in the handling and ultimate disposal of the finished compost. Collection of carcasses by
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tenderers presents a higher biosecurity risk, especially the risk of introducing disease from other
operations. In contrast, the ash from carcass incineration is sterile.
Carcass composting in the swine industry appears to be best suited for the disposal of pre-wean
and nursery mortalities because of the relatively small size of these carcasses. For larger animals
(sows, gilts, boars, and feeder pigs), at least partial carcass dismemberment, an unpleasant task,
is necessary.
Operational Factors: In the composting of swine mortalities, a single layer of carcasses or
carcass parts is placed on a layer of the carbon source and finished compost or manure, followed
by another layer of the carbon source and finished compost, and then carcasses. The pattern is
repeated until a height of about 5 feet is reached. The pile is capped with a carbon source.
Inadequate moisture will retard decomposition, whereas too much moisture will result in
anaerobic conditions and process failure.
A proper facility is critical to the success of composting swine carcasses. As noted above, one or
more of a series of two composting bins are required depending on the daily volume of carcasses
generated. To maximize the rate of carcass decomposition and also to ensure complete
decomposition of soft tissue, the composting mass should be transferred to a second bin after
about 2 weeks of decomposition. This transfer process results in both mixing and aeration of the
composting mass. Following an additional 2 weeks, the compost should be ready for storage and
curing or ultimate disposal. While satisfactory decomposition can be realized without transfer
and mixing, the time required is significantly longer.
Also critical to the success of composting swine carcasses is the initial combination of carcasses,
a source of biodegradable carbon such as sawdust or chopped straw, a source of adapted
microorganisms, and moisture. Although some cooperative extension publications recommend
using manure as the source of an adapted microbial population, finished compost is equally
suitable (Martin and Barczewski, 1996). The ratio, on a volume basis, of these ingredients
should be 1 part carcasses, 1.5 parts of the carbon source, 0.5 to 0.75 part finished compost, and
0 to 0.5 part water. The objective is to create an initial C to N ratio of 20:1 to 30:1.
Demonstration Status: The first use of composting for animal carcass disposal occurred in the
poultry industry during the 1980s (Murphy, 1988; Murphy and Handwerker, 1988). Since that
time, this method of carcass disposal has also been adopted by the swine industry. It was
estimated that 10.5 percent of swine operations use composting for mortality disposal (USDA
APHIS, 1995).
Practice: Incineration
Description: Incineration or cremation is the reduction of swine carcasses to ash by burning at a
high temperature under controlled conditions using specially designed equipment. Incineration
temperatures can be as high as 3,500 °F, depending on equipment design. Incinerators using
natural gas, propane, or No. 2 distillate fuel oil as a fuel are available.
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Application and Performance: Incineration of swine garcasses is applicable to all operations
where the cost of the equipment required can be justified by the volume of carcasses generated.
The potential for surface or ground water contamination associated with incineration is minimal,
provided that liquid fuel tanks are contained properly and residual ash is disposed of properly.
The P, K, and other elements contained in the carcasses are concentrated in the ash. Because of
the high temperature_of incineration, this ash is pathogen-free if cross-contamination with
carcasses is avoided.
Odors and other air quality concerns led to a significant decline in carcass incineration in the
past. Newly designed equipment, however, incorporates secondary combustion of stack gases,
essentially eliminating these problems. Yet the emission of low levels of some air pollutants is
unavoidable, as with any combustion process. Improper operation of the incinerator (e.g.,
reducing process temperature by overloading) can result in unacceptably high air pollutant
emissions.
Advantages and Limitations: One of the more attractive aspects of incineration relative to other
swine carcass disposal options, such as composting and rendering^ is the complete destruction of
pathogens. Another advantage is the relatively small mass of residual material (ash) requiring
some form of ultimate disposal, especially in comparison with composting. Moreover,
incineration has a relatively low labor requirement.
The principal perceived limitation of incineration is cost. The initial investment required is
relatively high. A recent comparison of incineration and composting costs for poultry carcass
disposal, however, suggests that the former has become cost competitive with the latter because
of lower labor costs and improvements in incinerator fuel efficiency (Wineland et al., 1998).
Another limitation of incineration for swine carcass disposal is fixed capacity. This can be
problematic when disease or other factors such as heat stresses cause a sizable increase in the rate
of mortality.
Operational Factors: Because of the fixed capacity of incineration equipment, incineration of
swine carcasses must occur on a regular basis. Ideally, carcass incineration should occur at least
on a daily basis to rninimize the potential for disease transmission. Routine maintenance of
incineration equipment is also important to ensure reliability and nuriimize emission of air
pollutants. An air pollutant emissions permit, a siting permit, or both, may be required for an
incinerator.
Demonstration Status: Incineration has been used in the swine industry as a method of carcass
disposal for many years. With recent technological advances in incinerator fuel efficiency and
odor control, a reversal in the shift away from incineration and to other carcass disposal options,
such as composting, may occur. It was estimated that 12.5 percent of swine operations use
incineration, described as burning, for mortality disposal (USDA APHIS, 1995).
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Practice: Rendering
Description: Rendering is the process of separating animal fats and proteins, usually by cooking.
The recovered proteins are used almost exclusively as animal feedstuffs, while the recovered fats
are used both industrially and in animal feeds.
There are two principal methods of rendering (Ensminger and Olentine, 1978). The first and
older method uses steam under pressure in large closed tanks. A newer and more efficient
method is dry rendering, in which all of the material is cooked in its own fat by dry heat in open
steam-jacketed drums until the moisture has been evaporated. One advantage of dry rendering is
the elimination of a separate step to evaporate the moisture in the material being rendered.
Cooking temperatures range from 240 to 290 °F. Rendering can be a batch or a continuous flow
process.
The two basic protein feedstuffs derived from rendering are meat meal and meat and bone meal.
The basis for this differentiation is P content (National Academy of Sciences, 1971). Meat meal
contains a maximum of 4.4 percent P on an as-fed basis. Meat and bone meal contains a
minimum of 4.4 percent P.
Application and Performance: Most of the animal fat and protein recovered by rendering is
derived from meat and poultry processing, but rendering can also be used to recover these
products from swine carcasses. The ability to use rendering as a method of swine carcass
disposal depends on the presence of a rendering facility servicing the area. Rendering plants are
not widely distributed and are generally located near meatpacking and poultry processing plants.
As the meatpacking and poultry processing industries have consolidated into fewer but larger
operations, a similar pattern of consolidation in the rendering industry has also occurred.
Because swine carcasses have minimal monetary value as a raw material for rendering,
transportation only over limited distances can be justified economically.
Rendering is a capital-intensive process and requires careful process control to generate
acceptable products. In addition, product volume has'to be substantial to facilitate marketing.
Because on-farm rendering is unlikely to be a viable option for swine carcasses, performance
measures are not included.
Advantages and Limitations: For swine producers, disposal of mortalities by rendering has
several advantages. One is that capital, managerial, and labor requirements are minimal in.
comparison with other carcass disposal options. A second advantage is the absence of any
residual material requiring disposal, as is the case with both composting and incineration, albeit
to a lesser degree. If carcass volume is adequate to justify daily pickup by the renderer, capital
investment for storage is also minimal.
As discussed above, rendering is a feasible option for swine carcass disposal only if the swine
production operation is located in an area serviced by a rendering plant. Also, not all rendering
operations will accept mortalities, largely because of concerns about pathogens in the finished
products.
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Well-managed rendering operations will not accept mortalities more than 24 hours after death
because of the onset of decomposition of fats and proteins, adversely affecting the quality of the
final products. For swine operations that do not generate an adequate volume of carcasses to
justify daily pickup by the Tenderer, carcass preservation by freezing, for example, is a necessity.
While preservation of piglet carcasses by freezing may be justifiable economically, the cost of
preserving larger animals is probably not justifiable because payment by Tenderers for carcasses
is usually nominal at best. Typically, payment is no more than one to two cents per pound.
Payment can be less, or there may even be a charge for removal, depending on transport distance.
Operational Factors: Since Tenderers usually pick up carcasses, stringent biosecurity
precautions are essential to prevent disease transmission by vehicles and personnel serving
several swine operations. Ideally, trucks should be disinfected before entering individual farms,
and collection personnel should use disposable shoe coverings. Also, necessary carcass
preservation measures should be employed to ensure that the Tenderer will continue to accept
carcasses.
Demonstration Status: It was estimated that 32 percent of swine operations use .rendering for
mortality disposal, with 25.1 percent allowing the Tenderer to enter the operation and 6.9 percent
placing carcasses at the perimeter of the operation for pickup (USDA APHIS, 1995).
Mortality Management: Poultry
Large poultry operations generate significant numbers of dead birds on a daily basis. For
example, a flock of 50,000 broilers with an average daily mortality of 0.1 percent (4.9 percent
total mortality) will result in approximately 2.4 tons of carcasses over a 49-day grow-out cycle
(Blake et al., 1990). A flock of 100,000 laying hens averaging a"0.5 percent monthly mortality (6
percent annual mortality) will generate 11.25 tons of carcasses per year (Wineland et al., 1998).
For a flock of 30,000 turkeys averaging 0.5 percent weekly mortality (9 percent total mortality),
approximately 13.9 tons of carcasses will require disposal (Blake et al., 1990).
Improper disposal of poultry mortalities can lead to surface or ground water contamination, or
both, as well as noxious odors and the potential for disease transmission by scavengers and
vermin. The following subsections briefly describe and discuss the principal alternatives, to
burial used for dead bird disposal: composting, incineration, and rendering. Burial of dead birds.
has been prohibited in many states, principally because of concerns regarding ground water
contamination. These alternatives for carcass disposal are also used in the swine industry and
have been described in the previous section. Differences between the two sectors, however, are
briefly noted.
Practice: Composting •
Description: The general description of composting presented in the preceding section on swine
mortality management also applies to poultry.
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Application and Performance: As with swine, composting as a method of carcass disposal is
suitable for all poultry operations. The compost produced can be spread on site if adequate land
is available. Another disposal option for the compost is distribution or marketing as an organic
fertilizer material or soil amendment. Thorough curing to preclude development of any odor or
vermin problems and screening to remove bones are necessary to make marketing of carcass
compost disposal a viable option. Another requirement for composting as a method of poultry
carcass disposal is the availability of a readily biodegradable source of organic carbon such as
sawdust, wood shavings, or straw.
When poultry carcass composting is managed correctly, potentially negative impacts on water
and air quality are essentially nonexistent, assuming proper disposal of the finished compost.
Mismanagement, however, can lead to seepage from the composting mass. This seepage has
high concentrations of oxygen-demanding organics, N, and P; is a source of noxious odors; and
attracts vermin.
Advantages and Limitations: As with swine carcass disposal, one of the advantages of poultry
carcass composting is the relatively low capital cost of the necessary infrastructure, especially
when compared with incineration. Depending on the volume of carcasses generated daily, one or
more of a series of two composting bins are required. These bins should be located on a concrete
pad in an open or partially enclosed shed-like structure. Critical to this capital cost advantage is
the availability of a skid-steer or tractor-mounted front-end loader for handling materials.
Federal and, in some instances, state and integrator cost sharing has been used to encourage the
construction and use of poultry mortality composting facilities.
A recent comparison of carcass composting and incineration for disposal of poultry mortalities
suggests, however, that the lower capital cost of carcass composting is offset by higher labor
costs (Wineland et al., 1998). The development of more fuel-efficient incinerators has made
incineration more cost competitive in recent years. „
While the temperatures that can be attained in a mass of composting carcasses (130 to 150 °F)
will result in significant reductions in pathogen densities, finished poultry mortality compost
cannot be considered pathogen-free. Therefore, appropriate biosecurity measures are necessary
in the handling and ultimate disposal of the finished compost. Collection of carcasses by
Tenderers presents a higher biosecurity risk, especially the risk of introducing disease from other
operations. In contrast, the ash from carcass incineration is sterile.
Operational Factors: In the composting of poultry mortalities, a single layer of carcasses is
placed on a layer of the carbon source and finished compost or litter, followed by another layer of
the carbon source and finished compost, and then carcasses. The pattern is repeated until a
height of about 5 feet is reached. The pile is capped with a carbon source. Inadequate moisture
will retard decomposition, while too much moisture will result in anaerobic conditions and
process failure. . .
A proper facility is critical to the success of composting poultry carcasses. As noted above, one
or more of a series of two composting bins are required depending on the daily volume of
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carcasses generated. To maximize the rate of carcass .decomposition and also to ensure complete
decomposition of soft tissue, the composting mass should be transferredto a second bin after
about 2 weeks of decomposition. This transfer process results in both mixing and aeration of the
composting mass. Following an additional 2 weeks, the compost should be ready for storage and
curing or ultimate disposal. While satisfactory decomposition can be realized without transfer
and mixing, the time required increases significantly.
Also critical to the success of composting poultry carcasses is the initial combination of
carcasses, a source of biodegradable carbon such as sawdust, wood shaving, or chopped straw, a
source of adapted microorganisms, and moisture. Although some cooperative extension
publications recommend using litter or cake as the source of an adapted microbial population,
finished compost is equally suitable (Martin and Barczewski, 1996). Martin et al. (1996) have
suggested that use of cake be avoided. One recommendation, on a volume basis, is 1 part dead
birds, 1.5 parts straw, 0.5 to 0.75 part litter, and 0 to 0.5 part water (Poultry Water Quality
Handbook, 1998). Sawdust or shavings have been used successfully in place of straw. Basically,
this same combination of materials is used for swine carcass composting. Again, the objective is
to create an initial C to N ratio of 20:1 to 30:1.
Demonstration Status: The first use of composting for animal carcass disposal occurred in the
poultry industry during the 1980s (Murphy, 1988; Murphy and Handwerker, 1988). Currently,
composting for disposal of poultry mortalities is readily accepted by producers and used
extensively. In a recent survey of broiler producers on the Delmarva Peninsula, 52.7 percent of
562 respondents reported using composting for dead bird disposal (Michel et al., 1996).
Practice: Incineration
Description: The general description of incineration presented in the precedingsection on swine
mortality management also applies to poultry.
Application and Performance: As with swine, the use of incineration for poultry carcass
disposal is applicable to all operations where the cost of the equipment required can be justified
by the volume of carcasses generated.
As with swine carcass incineration, the potential for surface or ground water contamination
associated with incineration is minimal, provided that liquid fuel tanks are properly contained
and residual ash is disposed of properly. The P, potassium, and other elements contained in the
carcasses are concentrated in the ash. Because of the high temperature of incineration, this ash is
pathogen-free if cross-contamination with carcasses is avoided.
Odors and other air quality concerns led to a significant decline in carcass incineration in the
past. Newly designed equipment, however, incorporates secondary combustion of stack gases,
essentially eliminating these .problems. Yet the emission of low levels of some air pollutants is
unavoidable, as with any combustion process. Improper operation of the incinerator (e.g.,
reducing process temperature by overloading) can result in unacceptably high air pollutant
emissions.
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Advantages and Limitations: One of the more attractive aspects of incineration relative to other
poultry carcass disposal options, such as composting and rendering, is the complete destruction
of pathogens. Another advantage is the relatively small mass of residual material (ash) requiring
some form of ultimate disposal, especially in comparison with composting. Moreover,
incineration has a relatively low labor requirement.
The principal perceived limitation of incineration is cost. The initial investment required is
relatively high. A recent comparison of incineration and composting costs for poultry carcass
disposal, however, suggests that the former has become cost competitive with the latter because
of lower labor costs and improvements in incinerator fuel efficiency (Wineland, et al., 1998).
Another limitation of incineration for poultry carcass disposal is fixed capacity. This can be
problematic when disease or other factors such as heat stresses cause a sizable increase in the rate
ofmortality.
Operational Factors: Because of the fixed capacity of incineration equipment, incineration of
poultry carcasses must occur on a regular basis. Ideally, carcass incineration should occur at
least on a daily basis to minimize the potential for disease transmission. Routine maintenance of
incineration equipment is also important to ensure reliability and minimize emissions of air
pollutants. An air pollutant emissions permit, a siting permit, or both, may be required for an
incinerator.
Demonstration Status: Incineration has been used to a limited degree in the poultry industry for
carcass, disposal for many years. In recent years,, cost and odor problems resulted in a shift away
from incineration to more seemingly attractive options such as composting. In a recent survey of
broiler producers on the Delmarva Peninsula, only 3.3 percent of 562 respondents reported using
incineration for dead bird disposal (Michel et al., 1996). Improvements in fuel efficiency and
odor control, however, have renewed interest in this option for carcass disposal.
Practice: Rendering
Description: The general description of rendering presented in the previous section on swine
mortality management also applies to poultry.
Application and Performance: As with swine, the ability to use rendering as a method of poultry
carcass disposal depends on the presence of a rendering facility servicing the area. Because
on-farm rendering is unlikely to be a viable option, performance measures are not included.
Advantages and Limitations: Rendering has the same advantages for poultry producers that it has
for swine producers: (1) minimal managerial and labor requirements; and (2) the absence of any
residual material requiring disposal.
Limitations include the need to preserve carcasses, because many operations will not generate a
sufficient volume of carcasses to justify daily collection by a renderer. Several options have
been demonstrated to be technically feasible for poultry carcass preservation. They include
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freezing, preservation using organic or mineral acids (Malone et al., 1998; Middleton and Ferket,
1998), preservation using sodium hydroxide (Carey et al., 1997), and lactic acid fermentation
(Dobbins, 1988; Murphy and Silbert, 1990). All of these preservation strategies increase the cost
of carcass disposal, and all but freezing increase labor requirements.
Another factor limiting the use of rendering for poultry carcass disposal is the problems that
feathers create in the rendering process. Feathers absorb the fat separated by rendering and make
the product difficult to handle and market. Feathers also dilute the nutritional and resulting -
market value of poultry by-products meal, especially when used as a feedstuff for nonrarnmant
animals which cannot digest feathers.
Although feathers can be removed by hydrolysis, cooking at high temperature under pressure,
protein quality is degraded. It has been shown, however, that feathers can be removed
successfully up to 24 hours postmortem, using a batch scalding and picking system (Webster and
Fletcher, 1998). Thus, Tenderers with feather picking equipment can accept significant quantities
of poultry mortalities without compromising product quality.
Operational Factors: As with swine, stringent biosecuriry precautions are essential to prevent
disease transmission by vehicles and personnel serving several poultry operations. Moreover,
carcass preservation measures are generally necessary. __
Demonstration Status: Overall, the use of rendering for disposal of poultry mortalities is
minimal because of the necessity of carcass preservation and the problem of feathers described
above. In a recent survey of broiler producers on the Delmarva Peninsula, none of the 562
respondents reported using rendering for dead bird disposal (Michel et al., 1996). One of the
major broiler integrators, however, is currently evaluating the use of rendering after the grower
preserves the carcasses by freezing. The integrator supplies the freezer and the grower pays for
the electricity. Preliminary indications are that the growers are pleased with this approach.
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S3 Nutrient Management Planning
Nutrient management is a planning tool farmers use to control the amount, source, placement,
form, and timing of the application of nutrients and soil amendments (USDA NRCS, 1999).
Planning is conducted at the farm level because nutrient requirements vary with such factors as
the type of crop being planted, soil type, climate, and planting season. The primary objective of a
nutrient management plan is to balance crop nutrient requirements with nutrient availability over
the course of the growing season. By accurately determining crop nutrient requirements, farmers
are able to increase crop growth rates and yields while reducing nutrient losses to the
environment.
Proper land application of manure is dependent on soil chemistry, timing of application, and
recommended guidelines for applying at agronomic rates (the amount of manure or commercial
fertilizers needed to provide only the amount of a particular nutrient that will be used by a
specific crop or crop rotation). Manure is an excellent organic fertilizer source and is a soil
amendment that benefits a soil's chemical, physical, and biological properties. The predominant
chemical benefit of manure to the soil is the supply of the major plant nutrients—N, P, and K. In
addition, livestock manure supplies micronutrients and non-nutrient benefits such as organic
matter, which are advantageous to plant growth. The organic matter increases the nutrient- and
water-holding capacity of the soil and improves the physical structure. Finally, manure is a
source of food and energy for soil microorganisms, which can directly and indirectly benefit the
physical, chemical, and biological properties of the soil. The combination of these non-nutrient
benefits to soil health has been found to boost com yields by 7 percent, soybean yields by 8
percent, and alfalfa yields by 9 percent (Vetsch, 1999).
In spite of the benefits listed above, repeated applications of manure can cause high levels of N,
P, K, and other micronutrients, as well as acidify soils and increase salinity. Excessive
application of these nutrients can lead to surface runoff or leaching. Therefore, land application
of manure, if improperly managed, can contribute to the degradation of surface water and ground
water (Liskey et al., 1992). Excessive amounts of some nutrients in soils can also reduce crop
yields (Brown, 1995).
More efficient use of fertilizer, animal manure, and process wastewater can result in higher
yields, reduced input requirements, greater profits, and improved environmental protection. It is
possible to further reduce fertilizer expenses and diminish water pollution by employing specific
farming practices that help to reduce nutrient losses from manured fields. The best ways to
conserve manure P and K are to apply only the amount of manure needed to meet the crop's
nutrient needs and use 'conservation practices that reduce erosion and runoff from fields. This
approach also aids in preventing N losses, but N management must also include proper handling,
storage, treatment, and timing of manure application and incorporation into the soil.
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CNMPs andPNPs: ;f *
When the sources of nutrients used on a farm include animal manure and process wastewater
manure management planning is incorporated within what is referred to by USDA (and described
in Section 8.3.1) as a comprehensive nutrient management plan or CNMP (USEPA 1999b)
EPA is proposing to require all CAFO operators to develop and implement a Permit Nutrient
Plan, or PNP. A PNP is a site-specific plan that describes how the operator intends to meet the
effluent discharge limitations and other requirements of the NPDES permit. EPA's PNP and
USDA's voluntary CNMP are very similar, and EPA used USDA's Technical Guidance for
Developing Comprehensive Nutrient Management Plans as the template for developing the PNP.
The PNP, however, establishes specific regulatory requirements that must be followed by CAFO
operators to ensure adequate protection of surface water. The PNP is also narrower in scope than
a CNMP since the CNMP guidance addresses certain aspects of CAFO operations that are not
included as part of EPA's effluent guidelines and standards. For example, the CNMP guidance
indicates that a CNMP should include insect control activities, disposal of animal medical
wastes, and visual improvement considerations, but EPA's proposed regulations and PNP do not
include such requirements.
The proposed PNPs are intended to be living documents that must be updated as circumstances
change. As the primary planning document for determining appropriate practices at the CAFO
the PNP must be developed and modified by a certified nutrient management specialist The
PNP is intended to establish the allowable manure application rate for land applying manure and
wastewater and to document how the rate was derived. The PNP would also describe other site-
specific conditions that could affect manure and wastewater application, sampling techniques to
be used in sampling manure and soils, the calibration of manure application equipment, and
operational procedures for equipment used in the animal production areas.
8.3.1 Comprehensive Nutrient Management Plans (CNMPs)
As discussed in the USDA-EPA Unified National Strategy for Animal Feeding Operations
(USEPA, 1999b), site-specific CNMPs may include some or all of the six components described
below, based on the operational needs of the facility. Many of the CNMP components described
in the strategy have been addressed in other parts of this document and are cross-referenced
below. This section focuses on parts of component 2 (Land Application of Manure and
Wastewater) and component 4 (Record Keeping), however, all six of the CNMP components, as
described in the strategy, are presented here to illustrate what a CNMP may contain.
Component 1: Manure and Wastewater Handling and Storage: This portion of a CNMP
addressed more fully in Section 8.2, identifies practices for handling and storing manure to
prevent water pollution. Manure and wastewater handling and storage practices should also
consider odor and other environmental and public health concerns. Handling and storage
considerations include the following:
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• Clean water diversion. Siting and management practices should divert clean water from
contact with feedlots and holding pens, animal manure, or manure storage systems.
Clean water can include rain falling on the roofs of facilities, runoff from adjacent land,
and other sources.
• Leakage prevention. Construction and maintenance of buildings, collection systems,
conveyance systems, and permanent and temporary storage facilities should prevent
leakage of organic matter, nutrients, and pathogens to ground or surface water.
• Adequate storage. Liquid manure storage systems should safely store the quantity and
contents of animal manure and wastewater produced, contaminated runoff from the
facility, and rainfall. Dry manure, such as that produced in broiler and turkey operations,
should be stored in production buildings or storage facilities or otherwise stored in such a
way as to prevent polluted runoff. The location of manure storage systems should
consider proximity to water bodies, floodplains, and other environmentally sensitive
areas.
• Manure treatments. Manure should be handled and treated to reduce the loss of nutrients
to the atmosphere during storage; make the material a more stable fertilizer when applied
to the land; or reduce pathogens, vector attraction, and odors, as appropriate.
• Management of dead animals. Dead animals should be disposed of in a way that does not
adversely affect ground or surface water or create public health concerns. Composting
and rendering are common methods used to dispose of dead animals.
Component 2: Land Application of Manure and Wastewater: Land application is the most
common, and usually the most desirable, method of using manure and wastewater because of the
value of the nutrients and organic matter they contain. Land application should be planned to
ensure that the proper amount of nutrients are applied in a manner that does not adversely affect
the environment or endanger public health. Land application in accordance with the CNMP
should minimize the risk of adverse impacts on water quality and public health. Considerations
for appropriate land application should include the following:
• Nutrient balance. The primary purpose of nutrient management is to achieve the level of
nutrients (e.g., N and P) required to grow the planned crop by balancing the nutrients
already in the soil and provided by other sources with those which will be applied in
manure, biosolids, and commercial fertilizer. At a minimum, nutrient management should
prevent the application of nutrients at rates that will exceed the capacity of the soil and
the planned crops to assimilate nutrients and prevent pollution. Soils, manure, and
wastewater should be tested to determine nutrient content.
• Timing and methods of application. Care must be taken when applying manure and
wastewater to the land to prevent them from entering streams, other water bodies, or
environmentally sensitive areas. The timing and methods of application should minimize
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the loss of nutrients to ground or surface watefeand the loss of N to the atmosphere.
Manure and wastewater application equipment should be calibrated to ensure that the
quantity of material being applied is what was planned. These topics are discussed in
Section 8.4.
Component 3: Site Management: Tillage, crop residue management, grazing management, and
other conservation practices should be used to minimize movement to ground and surface water
of soil, organic material, nutrients, and pathogens from lands to which manure and wastewater
are applied. Forest riparian buffers, filter strips, field borders, contour buffer strips, and other
conservation practices should be installed to intercept, store, and use nutrients or other pollutants
that might migrate from fields to which manure and wastewater are applied. Site management is
addressed in Section 8.4.
Component 4: Record Keeping: CAFO operators should keep records that indicate the quantity
of manure produced and how the manure was used, including where, when^ and the amount of
nutrients applied. Soil and manure testing should be incorporated into toe record keeping -'.
system. The records should be kept after manure leaves the operation.
Component 5: Other Utilization Options: Where the potential for environmentally sound land
application is limited, alternative uses of manure, such as sale of manure to other farmers,
centralized treatment, composting, sale of compost to other users, and using manure for power
generation may also be appropriate. Several of these options are described in Section 8.2. All
manure use options should be designed and implemented in such a way as to reduce risks to
•human health and the environment, and they must comply with all relevant regulations.
;
Component 6: Feed Management: Animal diets and feed may be modified to reduce the amounts
of nutrients in manure. Use of feed management activities, such as phase feeding, amino acid-
supplemented low-protein diets, use of low-phytate-phosphorus grain, and enzymes such as
phytase or other additives, can reduce the nutrient content of manure, as described in Section 8.1.
Reduced inputs and greater assimilation of P by the animal reduce the amount of P excreted and
produce a manure that has a nitrogen-phosphorus ratio closer to that required by crop and forage
plants.
Other information that should be part of a nutrient management plan is provided in the USDA-
NRCS Nutrient Management Conservation Practice Standard Code 590 (USDA NRCS, 1999); it
includes aerial photographs or site maps; crop rotation information; realistic crop yield goals; '
sampling results for soil, manure, and so forth; quantification of all nutrient sources; and the'
complete nutrient budget for the crop rotation.
Practice: Developing a Comprehensive Nutrient Management Plan
Description: Effective nutrient management requires a thorough analysis of all the major factors.
affecting field nutrient levels. In general, a CNMP addresses, as necessary and appropriate,
manure and wastewater handling and storage, land application of manure and other nutrient
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sources, site management, record keeping, and feed management. CNMPs also address other
options for manure use when the potential for environmentally sound land application of manure
is limited at the point where the manure is generated.
Nutrient management planning typically involves the use of farm and field maps showing
acreage, crops and crop rotations, soils, water bodies, and other field limitations (e.g., sinkholes,
shallow soils over fractured bedrock, shallow aquifers). Realistic yield expectations for the crops
to be grown, soil and manure testing results, nutrient analysis of irrigation water and atmospheric
deposition, crop nutrient requirements, timing and application methods for nutrients, and
provisions for the proper calibration and operation of nutrient application equipment are all key
elements of a nutrient management plan.
Application and Performance: CNMPs apply to all farms and all land to which nutrients are
applied. Plans are developed by the grower with assistance, as needed, from qualified company
staff, government agency specialists, and private consultants. To be effective, nutrient
management plans must be site-specific and tailored to the soils, landscapes, and management of
the particular farm (Oldham, 1999).
A wide range of studies has found that implementation of nutrient management plans result in
improved nutrient use efficiency. In some cases, producers increased nutrient applications based
on nutrient budget analyses, but reduced applications of N and P are more common. For
example, average annual nutrient application rates were reduced by 14 to 129 pounds per acre for
N and 0 to 106 pounds per acre for P in 19 USDA projects from 1991 to 1995 (Meals et al.,
1996). -The introduction of improved fertilizer recommendations hi Pennsylvania resulted hi a 40
percent reduction in N use statewide (Berry and Hargett, 1984). A pilot program on 48 farms in
Iowa resulted in an average reduction of 9.6 pounds per acre N because of improved nutrient
management (Hallberg et al., 1991).
Reductions in field losses of N and P due to implementation of nutrient management plans vary
considerably, but a comprehensive review of field and modeling studies concluded that load
reductions averaged 15 percent for N and 35 percent for P (Pennsylvania State University, 1992).
In a 6-year study of nutrient management hi Pennsylvania, basefiow loads of N and P forms
decreased, but stormflow discharges of total N and total P increased by 14 and 44 percent,
respectively (Langland and Fishel, 1996).
Advantages and Limitations: A good nutrient management plan should help growers minimize
adverse environmental impacts and maximize the benefits of using litter and manure. In a
national survey of growers of corn, soybeans, wheat, and cotton, more than 80 percent of those
who had used manure in the Northeast, southern plains, Southeast, and Corn Belt reported that
they had reduced the amount of fertilizer applied to land receiving manure (Marketing
Directions, 1998). Approximately 30 percent of the respondents reported that they had saved
money through crop nutrient management, while more than 20 percent reported increased yields,
about 18 percent claimed reduced fertilizer costs, and approximately 10 percent reported that
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profits had increased and the soil quality had improved. Despite the potential savings, some
fanners are reluctant to develop nutrient management plans because of the cost Only 4 to 22
percent of respondents indicated that they have a nutrient management plan.
Proper crediting and application of hog manure has been reported to save $40 to $50 per acre in
fertilizer expenses in Iowa (CTIC, 1998a). Similarly, injecting hog manure has resulted in
savings of $60 to $80 per acre in Minnesota. Although savings vary from farm to farm, proper '
crediting and application of manure under a good nutrient management plan can result in
considerable cost savings for producers.
When animal manure and litter are used as nutrient sources, those activities which affect the
availability and characteristics of such sources need to be factored into the nutrient management
plan. For example, a nutrient management plan in which poultry litter is used as a nutrient
source should take into account the amount of litter to be removed and the time of removal'so
that sufficient land is available for proper land application shortly after removal. Alternatively,
the plan would need to consider whether storage facilities are available for the quantity of
material that must be handled prior to land application. Whenever possible, Utter removal should
be planned so that fresh litter, containing the maximum amount of nutrients, can be applied
immediately to meet crop or forage plant needs.
The CNMP will need to be revisited and possibly revised if the livestock facility increases in
size, or if there are changes in animal types, animal waste management, processes, crops, or other
significant areas.
Nutrient management services are available in the major farming regions, and both low-tech and
high-tech options, such as precision agriculture, are available to producers. A CNMP is only as
good as the information provided; the extent to which assumptions regarding yield, weather, and
similar factors prove true; and the extent to which the plan is followed precisely.
Operational Factors: Climate, temperature, and rainfall are all critical factors to be considered
in the development of a nutrient management plan. Since CNMPs are site-specific, the
requirements of each CNMP will vary depending on the conditions at each facility.
Demonstration Status: A report on state programs related to AFOs indicates that 27 states
already require the development and use of waste management plans (USEPA, 1999a). The
complexity and details of these plans vary among states, but the plans typically address waste
generated, application rate, timing, location, nutrient testing, and reporting provisions. Further,
industry data and site visits conducted by EPA indicate that practically all CAFOs have some
form of management plan in place.
8.3.2 Nutrient Budget Analysis
For animal operations at which land application is the primary method of final disposal, a well-
designed nutrient management plan determines the land area required to accept manure at a set
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rate that provides adequate nutrients for plants and avoids overloading soils and endangering the
environment The four major steps of this process are as follows:
1. Determine crop yield goals based on site-specific conditions (e.g., soil characteristics).
2. Determine crop nutrient needs based on individual yield goals.
3. Determine nutrients available in manure and from other potential sources (e.g., irrigation
water).
4. Determine nutrients already available in the soil.- -
These four steps constitute a nutrient budget analysis, which provides the operator with an
estimate of how much animal waste can be efficiently applied to agricultural crops so that
nutrient losses are minimized. Various organizations, including Iowa State University (ISU,
1995), USDA NRCS (1998b), and USEPA (1999b), have developed guidance on performing
nutrient budget analysis. The Iowa State University guidance includes detailed worksheets for
estimating nutrient needs versus supply from animal manure and other sources.
83.2.1 Crop Yield Goals
Practice: Establishing Crop Yield Goals
Description: Establishing realistic yield goals should be the first step of a nutrient management
plan. The yield goal is the realistic estimate of crop that will be harvested based on the soil and
climate in the area (USDA NRCS, 1995). Realistic yield goals can be determined through the
following:
• Historical yield information (Consolidated Farm Service Agency-USDA)
• Soil-based estimates of yield potential (county soil survey books and current soil nutrient
content reports)
• Farmer's or owner's records of past yields
• Yield records from a previous owner
Yield potential is based on soil characteristics and productivity. The soil's yield potential can be
obtained from Soil Survey Reports, county extension agencies, or Natural Resources
Conservation Service (NRCS) offices. As the equation below shows, individual yield goals are
calculated by multiplying the total acreage of a certain soil type by the yield potential of that soil,
then dividing that sum by the total acres in the field:
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Total Acreage x Yield Potential (
Total Acres in the Field ~(
bu/acre (Individual Yield Goal)
Application and Performance: Realistic yield goals apply to all farms and all land to which
nutrients are applied. Yield goals can be developed by the grower with assistance, as needed,
from qualified company staff, government agency specialists, and private consultants. To be'
effective, yield goals must be site-specific, tailored to the soils on each field.
How well this practice performs depends on both good science and good fortune. Fanners are
typically encouraged to set yield goals 5 to 10 percent above the average yield for the past 5 years
or so (Hirschi et al.,'1997). The intent is allow the farmer to benefit from a good year, while still
reducing waste in the event that an off year occurs. Hirschi reports, however, that a survey of
farmers in Nebraska showed that only one in ten reached their yield goals, with a full 40 percent
of me farmers falling more than 20 percent below their yield goals.
Estimation of realistic yield goals does not address direct treatment or reduction of any
pollutants, but is essential to determining the proper manure and commercial fertilizer
application rates.
Advantages and Limitations: Reliance on a realistic yield goal is, by its very nature, an
advantage for farmers. The challenge is to establish a yield goal that is truly realistic. Farmers
who rely on their own yield records should use an average from the past 5 to 7 years, recognizing
that it is impossible to foretell growing seasons accurately (Oldham, 1999).
If yield goals are set too high, there is the risk that nutrients will be applied in excess of crop
needs. This translates into increased expense, increased levels of nutrients in the soil and
increased risk to surface water and ground water (Hirschi et al., 1997). If yield goals 'are set too
low, the crop yield may be diminished because of a lack of nutrients. Further, if the crop yield is
low durrng a bumper crop year, the producer risks a substantial loss of profits.
Universities publish yield goal information for use by farmers in all states, providing a ready
source of information in the absence of better, site-specific records. In addition, seed suppliers
have yield information that can be shared with farmers, including the results from local field
trials.
Operational Factors: A key challenge in estimating crop yield is determining which historic
yield data, industry data, and university recommendations are most appropriate for a given farm.
Farmers need to recognize that exceptionally good years are rare (Hirschi et al, 1997).
Assumptions regarding the year's weather are also key, and, because farming is a business, crop
prices affect farmers' estimates of realistic yield as well.
If planting dates are affected-by spring weather, yields may suffer, creating the potential for
overapplication of nutrients. Similarly, extended droughts or wet periods may affect yields. Hail
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and other similar weather events can also harm crops, resulting in actual yields that fall short of
even reasonable yield goals.
Demonstration Status: Estimation of crop yield is a basic feature of farming, although the
methods used and accuracy of the estimates vary.
83.2.2 Crop Nutrient Needs
Practice: Estimating Crop Nutrient Needs
Description: Crop nutrient needs are the nutrients required by the crop and soil to produce the
yield goal. Crop nutrient needs can be calculated for detailed manure nutrient planning. For
animal feeding operations, N and P are the primary nutrients of concern, and significant research
has been conducted on specific crop requirements for these nutrients. In some cases, nutrient
planning analyses also evaluate K requirements. ;
Crop nutrient needs can be estimated by multiplying the realistic yield goal by a local factor for
each nutrient-crop combination. For example, N factors for com are provided for three regions
in Iowa (USDA NRCS, 1995). If the yield goal is 125 bushels per acre and the N factor is 0.90,
the N need for corn is 112.5 pounds per acre (125 x 0.90).
Application and Performance: Estimation of crop nutrient needs is a practice that applies to all
farms and all land to which nutrients are applied. These estimates can be developed by the
grower with assistance, as needed, from qualified company staff, government agency specialists,
and private consultants. Nutrient uptake and removal data for common crops are available from
the NRCS, the local extension office, and other sources (Oldham, 1999).
The accuracy of this calculation depends on the accuracy of the yield goal and nutrient factors for
the crop. In the case of Iowa com, for example, N factors vary from 0.90 to 1.22. A farmer
preparing for a good year might add a 10 percent cushion to the yield goal of 125 bushels per
acre used above, resulting in a revised yield goal of 137.5 bushels, per acre. The N need increases
to 123.75 pounds per acre, an increase of 10 percent as well. If the year turns sour and the yield
is 112.5 bushels per acre (10 percent less), the excess N applied becomes 22.5 pounds per acre
(123.75-101.25) instead of 11.25 pounds per acre (112.5-101.25), or 100 percent greater.
Estimation of crop nutrient needs does not address direct treatment or reduction of any pollutants,
but is essential to determining the proper manure and commercial fertilizer application rates.
Advantages and Limitations: The determination of N needs should account for any N in the
organic fraction of manure that is not available the first year, any N carryover from previous
legume crops, N carryover from previous manure applications, and any commercial N that will
be applied. The major factors deterrnining the amount and availability of carryover N are the
total amount of N applied, N uptake in the initial crop, losses to air and water, N concentration,
carbon-to-nitrogen ratio, soil temperature, and soil moisture (Wilkinson, 1992).
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In their analysis of nutrient availability froni livestock, Lander et al. (USDA NRCS, 1998a)
assumed that 70 percent of N applied in manure wcjuid be available to the crop. Ammonia
volatilization, nitrate leaching, and runoff losses reduce the amount of available nutrient, and the
percentage available also varies depending on soil temperature, soil moisture, organism
availability, and the presence of other nutrients and essentials. When dry or liquid manure is
incorporated immediately following application in the north-central region of the United States,
about 50 percent of the N is available to the crop (Hirschi et al., 1997).
In North Carolina, it is estimated that half of the total N in irrigated lagoon liquid and 70 percent
of the total N in manure slurries that are incorporated into the soil is available to plants (Barker
and Zublena, 1996). Plant availability coefficients for N range from 25 percent (dry litter or
semisolid manure broadcast without cultivation, and liquid manure slurry irrigated without
cultivation) to 95 percent (injected liquid manure slurry and lagoon liquid), depending on form of
the manure and method of application (Barker, 1996). For both P and K,"the range is 60 to 80
percent, with the higher values for injection of liquid manure slurries and lagoon liquids, and
application of lagoon liquids through broadcasting or irrigation with cultivation. The lower
values in the range apply to broadcasting dry litter and semisolid manure with no cultivation.
The results from plot studies conducted on Cecil sandy loam in Georgia indicate that carryover N
from broiler litter should be factored into nutrient management planning for periods longer than 3
years (Wilkinson- 1992):
In Ohio, only about one-third of the organic N in animal manure is available to crops during the
year it is applied (Veenhuizen et al., 1999). The P and K in the manure are available'during the
year they are applied, as are the equivalent amounts of fertilizer-grade P and K. Ohio State
University Extension has published tables that show the estimated percentage of residual organic
N that will be available in the 10 years after initial application.
In addition to organic N in manure, other sources of N can be significant and are included in the
calculation of N needs:
• Mineralization of soil organic matter
• Atmospheric deposition
• Residue mineralization
• Irrigation water
Inappropriate, contributions from these sources should be subtracted from the total amount of N
needed. A general value for calculating the N mineralized per acre from soil organic matter
(SOM) is 40 pounds per year for each 1 percent of SOM. The amount of N from atmospheric
deposition can be as much as 26 pounds per acre per year, but local data should be used for this
estimate. Irrigation additions can be estimated by multiplying the N concentration (in parts per
million) by the quantity of water applied (in acre-inches) by 0.227 (USDA NRCS, 1996a).
As discussed earlier, nutrient planning based on N levels alone could lead to excessive soil P
levels, thereby increasing the potential for P to be transported in runoff and erosion. Soil P levels
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should be determined and compared with crop needs before manure or fertilizer containing P is
applied. This can be accomplished by comparing annual P removal rates based on the type of
crop planted with the amount of P applied the previous year. As with N, data are available for
plant removal rates by specific crop.
Operational Factors: As noted above, the major factors deterrnining the amount and availability
of carryover N include losses to air and water, soil temperature, and soil moisture (Wilkinson,
1992). In addition, mineralization of soil organic matter, atmospheric deposition, residue
mineralization, and irrigation water applications are all related to climate, temperature, and
rainfall.
Demonstration Status: Estimation of crop nutrient needs is a basic feature of farming. The
methods used vary, however, as does the accuracy of the estimates.
83.2.3 Nutrients AvaUable in Manure
Manure is an excellent fertilizer because it contains at least low concentrations of every element
necessary for plant growth. The most important macronutrients in manure are N, P, and K, all of
which come from urine and feces. The chemical composition of manure when it is excreted from
the animal is determined largely by the following variables:
• Species of animal
• Breed
Age
• Gender
• Genetics
• Feed ration composition
The composition of manure at the time it is applied usually varies greatly from that at the time it
was excreted from the animal. The nutrients in manure undergo decomposition at varying rates
influenced by the following factors:
• Climate (heat, humidity, wind, and other factors)
• Length of time the manure is stored
• Amount of feed, bedding, and water added to manure before removal from the animal
housing facility
• Type of production facility ' . -
• Method of manure handling and storage
• Method and timing of land application
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Use of manure/pit additives
Soil characteristics at time of application
• Type of crop to which manure is applied
Net precipitation/evaporation in storage structure
Uncontrollable anomalies (e.g., broken water line)
Ratio of nutrients that have been transformed and/or lost to the atmosphere or soil profile
Given these many factors, it is nearly impossible to predict the nutrient content of manure in
every animal production setting. Several state extension and university publications have
attempted to predict nutrient contents for different species of animals at specific production
phases. These book values are an educated guess at best and vary widely from state to state. It is
imperative that livestock producers monitor the nutrient content of their manure on a consistent
basis. Knowing the content of macronutrients in manure is an important step to proper land
application.
Nitrogen
The.total amount.of N in manure-is excreted in two forms. Urea, which rapidly hydrolyzes to
ammonia, is the major N component of urine. Organic N, excreted in the feces, is a result of
unutilized feed, microbial growth, and metabolism in the animal.
Total N = NH3 (ammonia) + organic N
The ratio of ammonia to organic N in the manure at the time of excretion is largely dependent on
species, feed intake, and the other factors discussed above.
Before land application, inorganic N forms can be lost either to the atmosphere or into the soil
profile, decreasing the nutrient value of the manure. Depending on the type of manure- handling
and storage system and other factors described above, variable amounts of organic N can be
mineralized to inorganic forms, which then can be lost to the atmosphere or into the soil profile.
Nitrogen can be lost from manure in the following three ways:
1. NH3 (ammonia) is volatilized into the atmosphere.
2. NO3 (nitrate, a product of mineralization and nitrification) undergoes denitrification and
is released into the atmosphere as N2 (inert N gas).
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3. NO3 (nitrate, a water soluble form of N) is leached and carried down through the soil
profile, where it is unavailable to plants.
Agitation of liquid manure prior to land application is extremely important. Solids will separate
from still manure. The liquid will largely consist of the mineralized, inorganic forms of N,
whereas the solid portions will contain the organic forms of N that are unavailable to plants.
Proper agitation suspends the solids and helps ensure that the manure will be a more uniform and
predictable fertilizer. -
When manure is applied to land, the N content exists in two major forms, the ratio of which can
be determined only by manure analysis. The amount of N that will be available to fertilize the
plant will depend on the method and timing of application. The balance of the N available to the
plant will be lost in one of the three ways described above or will remain immobilized in the
organic form. It is generally agreed that 25 to 50 percent of N applied in the organic form will
undergo mineralization and become available to plants hi the first year. The remaining organic N
will mineralize and become available in subsequent years.
When manure is applied to the surface of land without incorporation into the soil, much of the
inorganic N remains on the surface, is lost, and will never be available to the plant.
Volatilization of ammonia is the most significant loss factor and is greatest when drying
conditions (dry, warm; sunny days) dominate. Field estimates of volatilization loss from surface-
applied manure range from about 10 to 70 percent of ammonia N applied (CAST, 1996).
When manure is incorporated into the-soil, inorganic forms of N available to the plant are placed
directly into the root zone and volatilization is minimized. The inorganic ammonia/ammonium
is either taken up by the plant or converted to nitrate. The nitrate can then be taken up by the
plant, denitrified, and released into the atmosphere as N gas, or carried by water through the root
zone. In addition, the organic N fraction has more contact with soil microbes when incorporated,
resulting in a greater rate of mineralization.
Phosphorus
The vast majority of P contained in manure is derived from the feces. Only small amounts of P
are present in livestock urine. As with N, the amount of P excreted by an animal depends on
several factors already discussed.
The introduction of water, bedding, and feed into the manure can affect both the nutrient
concentration and the content of the manure product. Manure handling and storage have little
influence on the P concentration. Any loss of P is a result of runoff from feedlots or solids
settling in holding basins, storage tanks, or lagoons. This will not be a loss if it is collected and
used later.
Most of the P is present in solid manure. As -stated for N, proper agitation resuspends the solids
and makes the manure a more uniform and predictable fertilizer.
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Although method and timing of land application hafe little direct effect on the transformation of
P to plant-available forms, they greatly influence the potential loss of P through runoff.
Estimates of P vary widely (CAST, 1996); however, by current estimates, somewhere near 70
percent is available for plant uptake in the first year following manure application (Koelsch,
1997). "
Potassium
In most species, K is equally present in both urine and feces. Similarly, the amount of K in
manure is fairly constant between liquids and solids and is not influenced by agitation. As with
the other macronutrients, the amount of K excreted by an animal depends on a multitude of
factors already discussed.
As with P, the introduction of water, bedding, and feed to the manure can affect both the K
concentration and the content of the manure product. Manure handling and storage have little
influence on the K concentration. Any loss of K is a result of runoff from feedlots or solids
settling in holding basins, storage tanks, or lagoons. This will not be a loss if it is collected and
used later.
As for P, the method and riming of land application have little direct effect on the transformation
of K to plant-available forms, but they greatly influence the potential loss of K through runoff.
Most of the K in manure is in the soluble form and is therefore readily available for plant uptake.
Availability is estimated to be about 90 percent (Koelsch, 1997).
Swine Specific Information
Swine excrete approximately 80 percent of the N and P and approximately 90 percent of the K in
the feed ration (Sutton et al., 1996). Swine manure can be handled as a slurry, liquid (with the
addition of wastewater), or solid (with the addition of large amounts of bedding).
Estimates of the nutrient content of swine manure classified by manure handling type and
production phase are given in Table 8-19. The values were compiled from university, extension
service, and government agency publications from around the United States. The wide range of
values is due to the many factors discussed earlier in this section.
Poultry Specific Information
Excreted poultry manure has a moisture content of around 80 percent. It can be handled as a
slurry or liquid, or in a dry form with added bedding (referred to as litter). Estimates of the
nutrient content of chicken and turkey manure are given in Table 8-20. The values were
compiled from university, extension service, and government agency publications from around
the United States. The wide range of values is due to the many factors discussed earlier in this
section.
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Dairy Specific Information
Because of the variety of housing and production options associated with dairies, many dairies
have a combination of solid-, liquid-, and/or semisolid-based handling systems. Milking parlors
commonly generate a large amount of wastewater from frequent flushing and cleaning of
facilities and cows. Dry cows are often housed outdoors in open lots, while cows being milked
may be kept in covered or completely enclosed freestall bams or holding pens.
Estimates of the nutrient content of dairy manure classified by manure handling type are given in
Table 8-21. The values were compiled from university, extension service, and government
agency publications from around the United States. The wide range of values is due to the many
factors discussed earlier in this section.
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Table 8-19. Swine Manure Nutrient Content Ranges
Source
ASAE, 1998 .
USDA NRCS, 1996a (farrow, storage tank under slats)
USDA NRCS, 1996a (nursery, storage tank under slats)
USDA NRCS, 1996a (grow/finish, storage tank under
slats)
USDA NRCS, 199a6 (breeding/gestation, storage tank
under slats)
USDA NRCS, 1996a (anaerobic lagoon liquid)
USDA NRCS, 1996a (anaerobic lagoon sludge)
USDA NRCS, 1998a (Breeding hogs, after losses)
USDA NRCS, 1 998a (Other types of hogs, after losses) 3
Jones and Sutton, 1994 (farrow, pit storage)
Jones and Sutton, 1994 (nursery, pit storage)
Jones and Sutton, 1994 (grow/finish, pit storage)
Jones and Sutton, 1 994 (breeding/gestation, pit storage)
Jones and Sutton, 1994 (farrow, anaerobic lagoon)
Jones and Sutton, 1994 (nursery, anaerobic lagoon)
Jones and Sutton, 1994 (grow/finish, anaerobic lagoon)
Jones and Sutton, 1994 (breeding/gestation, anaerobic
lagoon)
Reichow, 1995 (no bedding)
Reichow, 1995 (bedding)
NCSU, 1994 (paved surface scraped)
NCSU, 1994 (liquid manure slurry)
NCSU, 1994 (anaerobic lagoon liquid)
NCSU, 1 994 (anaerobic lagoon sludge)
Units
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal •
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
Total N
12.4
29.2
40.0
52.5
25.0
2.9
25.0
3.3
2.8
_. J5.0
24.0
32.8
•25.0
4.1
5.0
5.6
4.4
10.0
8.0
13.0
26.5
4.7
24.4
NBC,
6.9
23.3
33.3
—
. —
1.8
6.3
— ,
—
7.5
14.0
19.0
12.0
3.0
3.8
4.5
3.3
6.0
5.0
5.6
16.8
3.8
5.9
P
4.3
15.0
13.3
22.5
'10.0
0.6
22.5
3.6
2.8
5.2
8.7
11.5
13.5
0.9
1.4
1.7
1.9
3.9
3.1
5.8
8.3
0.8
23.0
K
4.4
23.3
13.3
18.3
17.5
3.2
63.3
7.0
7.2
9.1
18-.3
22.4
22.4
1.7
2.7
3.5
3.3
6.6
5.8
7.6
12.6
4.0
5.4
—, data not available.
a selected for nutrient production calculations throughout this document
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Table 8-20. Poultry Manure Nutrient Content Ranges
Source
ASAE, 1998 (layer)
USDA NRCS, 1996a (layer, anaerobic lagoon supernatant)
USDA NRCS, 1996s. (layer, anaerobic lagoon sludge)
USDA NRCS, 1996a (layer with no bedding or litter)
Jones and Sutton, 1994 (layer, pit storage)
Jones and Sutton, 1994 (layer, anaerobic lagoon)
NCSU, 1994 (layer paved surface scraped)
NCSU, 1994 (layer unpaved deep pit storage)
NCSU, 1994 (layer liquid manure slurry)
NCSU, 1994 (layer anaerobic lagoon liquid)
NCSU, 1 994 (layer anaerobic lagoon sludge)
ASAE, 1998 (broiler)
USDA NRCS, 1996a (broiler litter)
USDA NRCS, 1998a (broiler, as excreted)
USDA NRCS, 1998a (broiler, after losses) *
Jones and Sutton, 1994 (broiler, pit storage)
Jones and Sutton, 1994 (broiler, anaerobic lagoon)
NCSU, 1994 (broiler litter)
NCSU, 1994 (stockpiled broiler litter)
NCSU, 1994 (broiler house manure cake)
ASAE, 1998 (turkey)
USDANRCS, 1996a (turkey litter)
USDA NRCS, 1998a (turkeys for slaughter, as excreted)
USDANRCS, 1998a (turkeys for slaughter, after losses) •
USDA NRCS, 1998a (turkey hens, as excreted)
USDANRCS, 1998a (turkey hens, after losses) •
Jones and Sutton, 1994 (turkey torn, pit storage)
Jones and Sutton, 1994 (turkey hen, pit storage)
Jones and Sutton, 1994 (turkey torn, anaerobic lagoon)
Jones and Sutton, 1994 (turkey hen, anaerobic lagoon)
NCSU, 1994 (turkey house manure cake)
NCSU, 1994 (stockpiled turkey Utter)
Units
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1 ,000 gal
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/ton
Total N
26.3
6.3
32.5
35.4
60.0
7.0
28.2
33.6
57.3
6.6
20.8
25.9
38.9
26.8
16.1
' 63.0
8.5
71.4
32.6
45.5
26.4
72.4
30.4
16.2
22.4
11.2
53.0
60.0
8.0
8,0
44.8
31.6
NH4
6.6
4.6
7.7
13.0
5.5
14.0
11.8
36.8
5.6
6.5
—
—
—
—
13.0
5.0
12.0
6.9
11.8
3.4
0.8
—
—
—
—
16.0
20.0
6.0
6.0
20.1
5.5
P
9.4
0.8
45.8
22.9
19.7
1.7
13.8
22.3
22.7
0.7
33.7
7.1
19.4
7.8
6.6
17.5
1.9
30.3
33.5
23.0
9.8
32.9
11.8
10.1
13.2
11.2
17.5
16.6
1.7
1.7
20.3
30.4
K
9.4
8.3
6.0
25.0
23.2
2.9
16.2
21.9
27.5
8.5
8.1
9.4
22.9
10.5
9.5
24.1
2.9
38.7
26.6
29.9
10.2
37.0
11.6
10.4
7.6
6.8
24.4
26.6
3.7
3.3
24.8
25.0
—, data not available.
'selected for nutrient production calculations throughout this document
8-150
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Table 8-21. Dairy Manure Nutrient Content Ranges
Source
ASAE, 1998
USDA NRCS, 1996a (as excreted, lactating cow)
USDA NRCS, 1996a (as excreted, dry cow)
USDA NRCS, 1996a (heifer)
USDA NRCS, 1996a (anaerobic lagoon supernatant)
USDA NRCS, 1996a (anaerobic lagoon sludge)
USDA NRCS, 1996a (aerobic lagoon supernatant)
USDA NRCS, 1998a (milk cows, as excreted)
USDA NRCS, 1998a (milk cows, after losses) ".
USDA NRCS, 1998a (heifer & heifer calves, as
excreted)
USDA NRCS-, 1998a (heifer & heifer calves, after
losses)3
Reichow, 1995 (dry without bedding)
Reichow, 1995 (dry with bedding) •
Jones and Sutton, 1994 (mature cow, pit storage)
Jones and Sutton, 1994 (heifer, pit storage)
Jones and Sutton, 1 994 (dairy calf, pit storage)
Jones and Sutton, 1994 (mature cow, anaerobic lagoon)
Jones and Sutton, 1994 (heifer, anaerobic lagoon)
Jones and Sutton, 1994 (dairy calf, anaerobic lagoon)
NCSU, 1994 (paved surface scraped)
NCSU, 1994 (liquid manure slurry)
NCSU, 1994 (anaerobic lagoon liquid)
NCSU, 1994 (anaerobic lagoon sludge)
Units
pounds/ton
pounds/ton
pounds/ton
pounds/ton "
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton •-
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
pounds/1, 000 gal
pounds/ton
pounds/1,000 gal
pounds/1, 000 gal
pounds/1,000 gal
Total N
10.5
11.3
8.8
7.3
1.7
20.8
0.2
10.7
4.3
6.1
1.8
9.0
9.0
31.0
32.0
27.0
4.2
4.3
3.0
10.3
22.0
4.9
19.2
NH4
1.8
— r
—
—
1.0
4.2
0.1
- —
—
—
- —
4.0
5.0
6.5
6.0
5.0
2.3
2.1
2.0
2.5
9:2
3.2
6.2
P
2.2
1.8
1.2
0.9
0.5
9.2
0.1
1.9
1.7
1.3
1.1
1.7
—
6.6
6.1
6.1
0.8
0.9
0.4
3.1
6.0
1.2
18.3
K
6.7
6.5
5.6
5.6
4.2
12.5
—
6.7
6.0
5.0
4.5
8.3
—
15.8
23.2
1919
2.5
2.5
2.1
7.1
16.6
5.4
7.7.
—, data not available.
a selected for nutrient production calculations throughout this document
8-151
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Beef Cattle Specific Information
Most beef cattle are produced in an open-lot setting, but some moderate-sized operations produce
beef in confinement. The nutrient content of feedlot manure is extremely difficult to quantify
because of inconsistency in collection methods and content. Varying amounts of dirt, bedding,
and precipitation are mixed with the bedding at different times of the year.
Estimates of the nutrient content of beef manure are given in Table 8-22. The ranges were
compiled from university, extension service, and government agency publications from around
the United States. The wide range of values is due to the many factors discussed earlier in this
section.
Practice: Manure Testing
Description: The nutrient composition of manure varies widely among farms because of
differences in animal species and management, and manure storage and handling (Busch et al.,
2000). The only method available for determining the actual nutrient content of manure for a
particular operation is laboratory analysis. Typical laboratory reports show the moisture content
and percentage of N, P, K, Ca, Mg, and Na, as well as the concentration (parts per million) of Zn,
Fe, Cu, Mn (McFarland et al., 1998; USDA NRCS, 1996a). Other information, such as the pH
and conductivity for liquid samples, is also provided.
Sampling should be performed as close as possible to the time of land application to limit error
resulting from losses occurring during handling, storage, and application (Schmitt, 1999; Busch
et al., 2000; Bonner et al., 1998; Sharpley et al., 1994). The best time to collect a representative
manure sample is during the loading or application process (Schmitt, 1999), but the test results
from such sampling cannot be used to plan the current manure applications. Sampling during
hauling is considered more accurate and safer than sampling at storage structures (Busch et al.,
2000). Subsamples should be collected from several loads and then composited into a single
sample. This applies to liquid, solid, or semisolid systems. Because the nutrients in manure are
not distributed evenly between the urine and feces portions, mixing is critical to obtaining a
representative sample.
Barker and Zublena (1996) recommend that land-applied manure be sampled and analyzed twice
annually for nutrient and mineral content. New sampling should be conducted whenever animal
management practices change. For example, if there is a significant change in animal rations or
operation management (e.g., a change hi the size or type of animals raised), new sampling should
be conducted. If manure is applied several times a year, samples should be taken during the
period of maximum manure application. For example, if the manure that has accumulated all
winter will be used as a nutrient source, sampling should be done before application in the
spring.
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Table 8-22. Beef Manure Nutrient Content Ranges
Source
ASAE, 1998
USDA NRCS, 1996a (as excreted, high forage diet)
USDA NRCS, 1996a (as excreted, high energy diet)
USDA NRCS, 1996a (feedlot manure)
USDA NRCS, 1998a (beef cows, as excreted)
USDA NRCS, 1998a (beef cows, after losses) a
USDA NRCS, 1998a (steers, calves, bulls, & bull calves,
as excreted)
USDA NRCS, 1998a (steers, calves, bulls, & bull calves,
after losses)3
USDA NRCS, 1998a (fattened cattle, as excreted)
USDA NRCS, 1998a (fattened cattle, after losses) a
Reichow, 1 995 (dry without bedding)
Reichow, 1995 (dry with bedding)
Jones and Sutton, 1994 (pit storage) .
Jones and Sutton, 1994 (anaerobic lagoon)
NCSU, 1994 (paved surface scraped)
NCSU, 1994 (unpaved surface scraped)
NCSU, 1994 (liquid manure slurry)
NCSU, 1994 (anaerobic lagoon, liquid)
NCSU, 1994 (anaerobic lagoon, sludge)
Units
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/ton
pounds/ton
pounds/1,000 gal
pounds/1,000 gal
pounds/1,000 gal
Total N
11.7
10.5
10.2
24.0
11.0
3.3
11.0
3.3
11.0
4.4
21.0
21.0
. 20.0
4.0
13.8
25.0
35.0
3.4
38.2
NH4
3.0
—
—
• -^— •
—
—
—
—
—
7.0
8.0
—
—
1.9
4.7
14.6
2.3
P
3.2
3.7
3.2
16.0
3.8
3.2
3.4
2.9
3.4
2.9
6.1
7.9
3.1
0.6
4.2
7.8
9.9
0.8
25.7
K
7.2
8.1
7.1
3.4
8.3
7.4
7.9
7.1
7.9
7.1
19.1
21.6
16.5
2.7
10.7
17.9
61.6
4.1
12.1
—, data not available.
a selected for nutrient production calculations throughout this document
For systems that are emptied or cleaned out once a year, it is recommended that sampling be
conducted each time the manure is applied (Busch et al., 2000). This applies to uncovered
lagoons, pits, basins, and stacking slabs. Manure from under-barn concrete pits or covered
aboveground tanks will not vary as much between applications, unless the type of animal or
another significant factor changes. Systems emptied twice a year or more might differ between-
application times, so a fall analysis might not be accurate for planning spring applications.
8-153
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Application and Performance: Manure sampling is a practice that applies to all farms and all
land on which manure is applied. The farmer or trained consultants can conduct the sampling.
Manure sampling does not address direct treatment or reduction of any pollutants, but is essential
to determining the proper manure and commercial fertilizer application rates.
Advantages and Limitations: Manure analysis is the only way in which the actual nutrient content
can be determined. Standardized tables of manure nutrient content do not reflect how variable
the true nutrient content can be, but they can be useful in planning facilities and land application
areas (Hirschi et al., 1997),
Convenient laboratory reports allow farmers to easily determine the pounds per ton of nutrients
in solid manure or pounds per acre-inch in liquid manure (McFarland et al., 1998). Laboratories
are available at universities in most states, and lists of service providers can be obtained from
county offices and the Internet.
Without manure analysis, farmers might buy more commercial fertilizer than is needed or spread .
too much manure on their fields (USDA NRCS, 1996a). Either practice can result in
overfertilization, which, in turn, can depress crop yields and cut profits. Improper spreading of
manure also can pollute surface and ground water.
Sampling from manure application equipment is quick, but the test results cannot be used to plan
the current year's manure applications. Sampling before hauling allows use of the test results for
the current year, but retrieving an accurate sample is difficult because the manure is not mixed.
Further, there is the danger of falling into manure storage structures.
Operational Factors: Sample collection procedures vary considerably depending on manure
form and storage, but all are intended to provide representative samples in a safe and convenient
manner. Homogeneity is the key to simple sampling procedures, but the nutrient content of
manure usually varies considerably within storage structures and stockpiles. For this reason,
agitation of liquid manure and mixing of solid manure are generally recommended prior to
sampling. Alternatively, several samples can be taken from different locations and depths within
a lagoon, pit, or manure stack. Sampling each of several loads of hauled manure is another
option to address spatial variability of manure nutrient content. The process of agitating and
loading manure is believed to provide mixing that ensures representative sampling (Busch et al.,
2000).
The number of samples to be taken for suitable results depends on the variability of the manure
sampled (Busch et al., 2000). One sample may be adequate for agitated liquid slurries and
lagoon liquids, whereas three or more samples may be needed for stacked solids. It is
recommended that one sample be taken per poultry house.
8-154
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Hirschi et al. (1997) recommend taking solid manure samples from several locations in a manure
stack or on a feedlot, mixing them together in a tied, 1-gallon plastic bag, placing that bag inside
another bag, and then freezing the sample before shipping to a laboratory for analysis.
Buseh et al. (2000) say that 10 to 20 subsamples should be taken from different depths and
locations using a pitchfork or shovel. In Texas, five to seven random subsamples are
recommended (McFarland et al., 1998). The subsamples are placed in a pile and mixed before a
composite sample is taken.
Busch et al. (2000) recommend that samples be taken from the manure in the tank or spreader
box on its way to the field for application. For solid manure, samples should be collected from
application equipment using a pitchfork, shovel, or plastic glove, avoiding large pieces or chunks
of bedding. The sample taken to the lab should be a mixture of manure taken from several (5 to
10) loads representing the beginning, middle,,and end of the application process. Subsamples
should be mixed thoroughly, prior to filling a sample jar three-fourths full, allowing room for gas
expansion. Jars should be cleaned and sealed in a plastic bag, and samples should be frozen
before being mailed.
Bonner et al. (1998) suggest that samples can be collected by using catch pans hi the field as the
material is applied to the land. Sampler from multiple pans are mixed to form the overall
sample, and a 1-liter plastic bottle is filled halfway to allow for gas expansion. Samples should
be frozen or kept cold until delivered to a laboratory.
Rather than sampling from the lagoon or pit, samples can be retrieved with a plastic pail or a
coffee can on a pole from the top of the spreader or from the-bottom unloading port (Busch et al.,
2000). Sampling should be done immediately after fillingr
Hirschi et al. (1997) recommend agitating or mixing liquid manures prior to sampling unless it is
more practical to take samples from several areas within a lagoon or pit and then mix them. To
sample from lagoons and storage facilities, a plastic container attached to a pole or rod is
recommended (Bonner et al., 1998; McFarland et al., 1998; Busch et al., 2000). Alternatively, a
Vz- or 3/4- inch PVC pipe can be pushed into the manure to a depth no closer than 1 foot from the
bottom (Busch et al., 2000). The sample can be secured by placing a hand over the top of the
pipe and pulling the pipe up. Samples should be taken from 5 to 10 locations around the lagoon,
covering several depths to include solids. After mixing the samples in a bucket, a representative
sample is then taken to a laboratory for analysis.
Demonstration Status: Manure sampling is practiced widely across the United States, but many
farmers still do not test manure or employ a N credit from manure when determining commercial
fertilizer needs (Stevenson, 1995). A 1995 survey of1,477 swine producers showed that 92
percent of operations had not had their manure tested for nutrients within the past 12 months
(USDA APHIS, 1995). Approximately 6 percent had tested their manure for nutrients once
during the past 12 months, while another 1.5 percent had tested it twice. These findings are
supported by a crop nutrient management survey in which only 2 to 17 percent of respondents in
8-155
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various regions stated that they factored manure nutrient values into their nutrient management
plans (Marketing Directions, 1998).
83.2.4 Nutrients Available in Soil
*
A major problem in using organic nutrient sources such as animal waste is that their nutrient
content is rarely balanced with the specific soil and crop needs. For example, the N: P ratio in
applied manure is usually around 3 or less, whereas the ratio at which crops use nutrients
typically ranges from 5 to 7. Therefore, when manure is applied at rates based solely on N
analysis and crop need for N, P is applied in excess of crop needs. Because the amounts of P
added in manure exceed the amounts removed by crops, continuous use of manure can result in
accumulations of excess P in the soil, increasing the potential for P to be transported in runoff
and erosion (Sharpley et al., 1999).
A recent change of emphasis in nutrient management programs has been to base manure
application rates on both P and N needs. Different soil types can accommodate different P
concentrations before experiencing significant P export in runoff. The amount of P that a soil
can hold depends on the availability of binding sites. For example, a clayey soil will tend to be
able to retain more P than a sandy soil because clays have a greater surface area and typically
contain a greater proportion of iron, which has a strong affinity for P. Table 8-23 demonstrates
the variability of the P binding capacity of several soils. Phosphorus bound to soils is primarily
in a particulate form; however, as a soil becomes saturated with P, the finite number of binding
sites will be overwhelmed and P can be released into runoff in a soluble form.
Table 8-23. Maximum P-Fixation Capacity of
Several Soils of Varied Clay Contents
Soil Great Group (and series)
Evesboro (Quartzipsamment)
Kitsap (Xerochrept)
Matapeake (Hapludult)
Newberg (Haploxeroll)
Location
Maryland
Washington
Maryland
Washington
Percent
clay
6
12
15
38
Maximum P fixation
(mgP/kgsoil)
125
453
465
905
Source: Brady and WeH, 1996.
The concept of a P threshold (TH) has been developed to identify soil P levels at which soluble
losses of P in runoff become significant. The recently revised USDA NRCS nutrient
management policy (Part 402) addressing organic soil amendments, such as manures, proposes
that for soils with a known P TH the following P manure application rates apply:
• If soil P levels are below 75 percent of the P TH, N-based manure application is allowed.
8-156
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• If soil P levels are between 75 percent and 150 percent ofthe P TH, manure application
rates should be based on the amount of P estimated to be removed by the crop.
• If soil P levels are between 150 percent and 200 percent of the P TH, manure application
rates should be based on one-half the amount of the P estimated to be removed by the
crop.
• If soil P levels are greater than twice (200 percent) the P TH, no manure should be added
to the soil.
• When no soil-specific TH data are available, P application should be based on soil P test
levels.
• If the soil P test level is low or medium, the application rate of organic soil amendments
(e.g., manure) can be based on the soil's N content.
• If the soil P level is high, the manure application rate should be based on 1.5 times the P
estimated to be removed by the crop.
• If the soil P level is very high, the manure application rate should be based on the P
estimated to be removed by the crop.
• If the soil P level is excessive, no manure should be applied.
Using this threshold concept, several states are developing P indexes to account for site-specific
conditions that influence both soluble P losses and particulate P losses resulting from erosion
(Lemunyon and Gilbert, 1993; Sharpley, 1995). This approach would categorize agricultural
fields using a quantitative index that can be helpful in assessing the potential risk of P
contamination of local water bodies. Manure and fertilizer application programs can then be
developed accordingly. For instance, an area prone to P transport, such as a field rich in P
located on credible soils adjacent to a reservoir, would receive a high score identifying the
importance of a strict nutrient management program. The economic concerns raised by a P-based
plan may be significant because a larger land area may be required in. order to dispose of manure
from livestock operations.
Practice: Soil Testing
Description: Soil testing, an important tool for determining crop nutrient needs, evaluates the
fertility of the soil to determine the basic amounts of fertilizer and lime to apply (USDA NRCS,
1996a). Soil tests should be conducted to determine the optimum nutrient application of N and
P, pH, and organic matter. Typical laboratory reports show soil pH, P, K, Ca, Mg, Zn, and Mn
levels, plus fertilizer and lime recommendations (USDA NRCS, 1996a). Special analyses for
organic matter, nitrate-N, and soluble salts can be requested.
8-157
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The best time to sample soil is after harvest or before fall or spring fertilization. Late summer
and fall are best because 1C test results are most reliable at these times (Hirschi et al., 1997). The
worst time to sample is shortly after the application of lime, commercial fertilizer, or manure, or
when the soil is extremely wet. Samples are usually composited to determine a general
application rate for a specific field or field section. The goal is to obtain a rqjresentative view of
the field conditions. This can be achieved by sampling in areas that have similar soil types, crop
rotation, tillage type, and past fertility programs. In addition, soil samples should be taken at
random in a zigzag pattern, making sure to avoid irregularities in the land (e.g., fence lines, very
wet areas) to get samples that accurately portray the landscape. Two weaknesses of random
sampling in a zigzag pattern are the assumptions that the composite sample is representative of
the entire field and that the result of the sampling produces an average value for the field
(Pocknee and Boydell, 1995). Samples can be gathered and composited over smaller areas to
determine distinct treatment options. To evaluate the variability of the land, the grid method of
dividing the field into 5-acre plots can also be used. Treatment decisions can be made by
balancing labor requirements, environmental concerns, and economics.
Grid-cell sampling and grid-point sampling are two sampling methods used on farms where
precision farming is practiced. In grid-cell sampling, an imaginary grid is laid over the sampling
area and soil cores are taken randomly within each cell, bulked,, and mixed. A subsample is then
taken from the composite sample for analysis. This approach is considered similar to the random
sampling method, with the exception that the sampled area is divided up into many smaller
"fields." In grid-point sampling, a similar imaginary grid is used, but the soil cores are taken
from within a small radius of each grid intersection, bulked, mixed, and subsampled for analysis.
Each of these methods hasits limitations. Grid-cell .sampling is very time-intensive because
most of the field needs to be covered in the sampling process, whereas grid-point sampling will
not work well unless grid sizes are very small. Thus, both methods tend to be expensive because
of the labor involved. A newer method, directed sampling, is.based on spatial patterns defined
by some prior knowledge about a field. Sampled areas are divided into homogeneous soil units
of varying size. Factors such as field management history, soil maps, soil color, yield maps,
topography, and past soil tests are combined and analyzed using a geographic information system
(GIS) to determine optimal sampling patterns.
Sampling equipment for grid sampling includes four-wheelers and trucks equipped with global
positioning system (GPS) capabilities and mechanized sampling arms (Pocknee and Boydell,
1995). Costs for custom service range from $7 to $15 per acre, including soil sampling, analysis
of standard elements, and mapping.
Recommendations regarding sampling frequency range from once a year to once every 4 years.
In Arizona, soil sampling for residual nitrate content analysis is recommended prior to planting
annual crops (Doerge et al., 1991). For sandy soils in North Carolina, sampling is recommended
once every 2 to 3 years; testing once every 4 years is suitable for silt and clay loam soils (Baird et
al., 1997). A minimum frequency of once every 4 years is generally recommended hi the central
United States (Hirschi et al., 1997). In Mississippi, soil samples should be taken once every 3
years or once per crop rotation (Grouse and McCarty, 1998).
8-158
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Application and Performance: Soil sampling is a practice that applies to all farms and all land to
which nutrients are applied. The farmer or trained consultants can conduct the sampling.
Soil sampling does not address direct treatment or reduction of any pollutants, but is essential to
determining the proper manure and commercial fertilizer application rates.
Advantages and Limitations: Soil analysis is the only way in which the actual nutrient content
can be determined. Nitrogen testing has not been consistently reliable because N is highly
mobile in soil, but drier parts of the Corn Belt have had some success with both the early spring
nitrate-N test and the pre-sidedress N test (Hirschi et al., 1997). There is also some evidence that
the pre-sidedress test is most helpful on soils to which manure has been applied.
/
A late spring N test ensures that the proper amount of N was applied to the crops. Because this
test is used to make site-specific adjustments of application rates, following the
recommendations provided by this test can help achieve expected crop yields. For example,
where N is too high, the late spring N test will indicate that additional N application is not
needed by the crop and may contaminate water supplies. Records should be kept and
adjustments made to N applications on future crops.
Without soil analysis, farmers might buy more commercial fertilizer than is needed or spread too
much manure on their fields (USDA NRCS, 1996a). Either practice can result in
overfertilization, which, in turn, can depress crop yields and cut profits. Improper spreading of
manure also can pollute surface and ground water.
Convenient laboratory reports allow farmers to easily determine the pounds of nutrients per acre
of soil (McFarland et al., 1998). Recommendations based on soil testing results are developed
using crop response data from within a state or region with similar soils, cropping systems, and
climate (Sims et al., 1998). For this reason, it is important to send samples to a laboratory that is
familiar with the crops, soils, and management practices that will be used on the particular farm.
The better the information provided to laboratories for each soil sample—such as previous
fertilizer use, management plans, and soil series—the greater the potential for receiving a better
recommendation. Laboratories are available at universities in most states, and lists of service
providers can be obtained from county offices and the Internet.
Operational Factors: Soil samples can be taken with a probe, auger, or spade and collected in a
clean bucket. Probes and augers are preferred because they provide an equal amount of soil from
each depth (Grouse and McCarty, 1998). For uniform fields, one sample is satisfactory, but most
fields are not uniform in treatment, slope, soil type, or drainage, and so should be divided into
small areas of 5 to 10 acres each for sampling (USDA NRCS, 1996a). It is recommended that a
soil map be used to guide sampling, and a separate, composite soil sample should be taken for
each distinct kind of land, soil texture, soil organic matter, fertility level, and management unit
(Grouse and McCarty, 1998> The samples should be taken from 20 or more places in the field,
using a zig-zag pattern (USDA NRCS, 1996a). Samples should not be taken from unusual areas
such as turn rows, old fence rows, old roadbeds, eroded spots, areas where lime or manure have
8-159
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been piled, or in the fertilizer band of row crops, A soil auger, soil tube, or spade can be used for
sampling at the plow depth for cropland (6 to 8 inches or more) and at 2 to 4 inches for pasture.
Samples should be placed in a clean plastic pail, mixed thoroughly with all clods broken up, and
then sent to a laboratory in a 1/2-pint box for analysis.
Recommendations regarding the appropriate field size to be sampled vary somewhat, as shown in
Table 8-24.
Table 8-24. Recommended Field Size for Soil Sampling
Location
Arizona
Hawaii
Minnesota
North Carolina
Texas
U.S.
U.S.
Field Size
40 acres or less
2-5 acres
5-20 acres
20 acres or less
10-40 acres
20-30 acres
5-10 acres
Comments
15-20 subsamples .
5-10 subsamples
15-20 subsamples
15-20 subsamples
10-15 subsamples
20-25 subsamples
20 or more subsamples
Source
Doerge et al, 1991
Hue etal., 1997
Rosen 1994
Baird et al., 1997
McFarland etal., 1998
Sims et al., 1998
USDANRCS, 1996a
Sampling for the early spring nitrate-N test involves taking soil samples in 1-foot increments
down to a depth of 2 to 3 feet in early spring, while the pre-sidedress N test calls for sampling
from the top 1 foot of soil when corn is 6 to 12 inches tall (Hirschi et al., 1997). Guidelines on
interpretation of early spring nitrate tests vary across states.
Phosphorus soil tests are based on the chemical reactions that control P availability in soils (Sims
et al., 1998). These reactions vary among soils, so a range of soil tests is available in the United
States, including the Bray PI (used in the North Central and Midwest Regions), Mehlich 3 (in
widespread use in the United States), Mehlich 1 (Southeast and Mid-Atlantic), Morgan and
Modified Morgan (Northeast), and Olsen and AB-DTPA (West and Northwest).
Demonstration Status: Soil testing is widely practiced in the United States. In a national survey
of com, soybeans, wheat, and cotton growers, 32 to 60 percent of respondents said that they
perform soil testing (Marketing Directions, 1998).
8.3.2.5 Manure Application Rates and Land Requirements
Practice: Determining Manure Application Rates and Land Requirements
Description: The final step of a nutrient management analysis is to determine the amount of
manure that can be applied to field crops to meet crop needs while simultaneously preventing
excessive nutrient losses. This step involves using the information developed in the nutrient
budget analysis to compare crop nutrient requirements with the supply of nutrients provided per
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unit volume of animal waste. Soil testing helps in detennining the rates at which manure should
be applied by establishing which nutrients are already present in the soil and available to the
crop. Testing manure identifies the amount and types of nutrients it contains and helps to ensure
that nutrients are not overapplied to the land. Depending on the cropping system, different
amounts of nutrients will be required for optimum production. This final analysis allows the
operator to determine how much land acreage is required to apply the animal manure generated
or, conversely, how much manure can be applied to the available acreage. These final
calculations are illustrated in Figures 8-13 and 8-14.
Figure 8-13 illustrates that two possible strategies for determining the correct agronomic
application rate of manure are (1) applying enough manure to ensure the proper amount of N is
available to the crop and (2) applying manure based on desired amounts of P, then adding
commercial N and K to make up the differences in crop needs. Depending on the frequency of
application, the first method might increase the risk of oversupplying P and K, thereby
potentially adversely affecting soil and water quality (Dick et al., 1999). For this reason, the
strategy requiring the greater land area for spreading is selected in the analysis illustrated by
Figure 8-13.
Application and Performance: Determining manure application rates and land requirements
applies to all farms and all land to which manure is applied. This analysis does not address direct
treatment or reduction of any pollutants, but is essential to detennining the proper manure and
commercial fertilizer application rates.
Determine land area needed for manure application. " ' ' " *
Total pounds of usable nutrients available and pounds of nutrients available to plants in eacfi.
gallon have been calculated. This information should be used to calculate the number of
acres you need for manure application. " """ ?~ ' s V ,
From nitrogen planning:
Net usable nitrogen available
Netnitrogen amount -5-
Land area needed for spreading nitrogen: =
From phosphorus planning:
Net usable P2OS available:
Total P2O5 needs:
Jb
.IbN/acre
acres
Ib
Land area needed for spreading P2O5: =
Acres required-
Greater of the two above values (a or b):
Adapted from Iowa State University, 1995.
.lbP2
-------
Determine manure volume to apply.
Total annual volume of manure:
Land area required for spreading:
Manure volume used on field:
.galorT
.acres
. gal or T/acre
If the field is smaller than the acres calculated above, calculate the manure to apply to this '
field:
Land area in field:.
Manure volume to apply:
Manure volume used on field:
acres
.gal or T/acre
_ galorT
Determine the number of gallons or tons of manure remaining to be spread:
Total annual volume of manure:
Manure volume used on fiekk
Manure volume remaining:
Manure volume remaining:
Manure volume to apply-
Additional land area for spreading:
Adapted from Iowa State University, 1995.
,*gal orT
.galorT
.galorT
.galorT
.gal or T/acre
"acres * ,
Figure 8-14. Example Calculations for Determining Manure Application Rate
Advantages and Limitations: Without this analysis, farmers may buy more commercial fertilizer
than is needed or spread too much manure on their fields (USDA NRCS, 1996a). Either practice
can result in overfertilization, which, in turn, can depress crop yields and cut profits. Improper
spreading of manure also can pollute surface and ground water.
In cases where there is inadequate land to receive manure generated on the farm, alternative
approaches to handling the manure, described elsewhere in this document, need to be considered.
Operational Factors: Although the correct manure application rate is determined by soil and
manure nutrient composition, as well as the nutrient requirements for the crop system, further
consideration should be given to soil type and timing of application. Attention to these factors
aids in determining which fields are most appropriate for manure application. Before applying
manure, operators should consider the soil properties for each field. Coarse-textured soils (high
sand content) accept higher liquid application rates without runoff because of then: increased
permeability; however, manure should be applied frequently and at low rates throughout the
growing season because such soils have a low ability to hold nutrients, which creates a potential
for nitrate leaching (NCSU, 1998). Fall applications of animal manure on coarse-textured soils
are generally not recommended. Fine-textured soils (high clay content) have slow water
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infiltration rates, and therefore application rates of manure should be limited to avoid runoff.
Application on soils with high water tables should be limited to avoid nitrate leaching into
ground water (Purdue University, 1994).
Demonstration Status: A 1995 survey of 1,477 swine producers showed that 92 percent of
operations had not had their manure tested for nutrients within the past 12 months (USDA
APHIS, 1995). Approximately 6 percent had tested their manure for nutrients once during the
past 12 months, while another 1.5 percent had tested it twice. These findings are supported by a
crop nutrient management survey in which only 2 to 17 percent of respondents in various regions
stated that they factored manure nutrient value into their nutrient management plans (Marketing
Directions, 1998). Like manure testing, analysis of land requirements and application rates is
practiced widely across the United States, but many farmers still do not test manure or employ a '
N credit from manure when determining commercial fertilizer needs (Stevenson, 1995).
8.3.3 Record Keeping
The key to a successful nutrient management system is sound record keeping. Such a record-
keeping regime should include the following:
Practice: Record Keeping
Description: Record keeping for a CNMP includes recording manure generation; field
application (amount, rate, method, incorporation); the results and interpretation of manure, soil
and litter analysis; visual inspections of equipment and fields; manure spreader calibration
' worksheets; manure application worksheets (nutrient budget analyses); and related information
on a monthly or more frequent basis.
Application and Performance: Record keeping applies to all farms and all land to which nutrients
are applied. Record keeping does not address direct treatment or reduction of any pollutants but
is essential to tracking the results of activities associated with nutrient management.
Advantages and Limitations: Without record keeping, farmers will have little ability to
determine what works and does not work with regard to on-farm nutrient management. Failure
to learn from past successes and mistakes may cause farmers to continue in an endless loop of
buying more commercial fertilizer than is needed, spreading too much manure on their fields and
realizing smaller profits than would otherwise be obtainable. For example, tracking manure '
sampling locations, dates, and methods will help establish a firm basis for adjusting sampling
frequencies to provide an accurate assessment of manure nutrient content (Busch et al., 2000).
Record keeping can seem to'be nothing but a burden unless tools are provided with which
farmers can analyze the information for then- own benefit. Fortunately, a great number of tools
are currently available from universities and industry to help farmers use their records to make
better business decisions. For example, MAX (Farming for Maximum Efficiency Program) is a
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program designed to help fanners look at their profit margins, rather than just their yields (CTIC,
1998b). MAX software is provided to cooperators to help them document their savings.
Operational Factors: Record keeping can be performed using pencil and paper, personal
computers, portable computers, or GIS-based systems.
Demonstration Status: Record keeping of some form is conducted on all farms as a matter of
business.
83.4 Certification of Nutrient Management Planners
Practice: Training and Certification for Nutrient Management Planners
Description: CNMPs should be developed or modified by a certified specialist. Certified
specialists are persons who have a demonstrated ability to develop CNMPs in accordance with
applicable USDA and state standards and are certified by USDA or a USDA-sanctioned
organization. Certified specialists would include individuals who have received certifications
through a state or local agency, third-party organization approved by NRCS, or NRCS personnel.
In addition, USDA develops agreements with third-party vendors similar to the 1998 agreement
with the Certified Crop Advisors (CCAs) and consistent with NRCS standards and specifications
(or state standards if more restrictive).1 CCAs provide technical assistance to producers in
nutrient management, pest management, and residue management. The purpose of using a
certified specialist is to ensure that CNMPs are developed, reviewed, and approved by persons
who. have the appropriate knowledge and expertise to ensure that plans fully and effectively
address the core components of CNMPs, as appropriate and necessary, and that plans are
appropriately tailored to the site-specific needs and conditions of the farm. Because of the
multidisciplinary nature of CNMPs, it is likely that a range of expertise will be needed to develop
an effective CNMP (e.g., professional engineer, crop specialist, soil specialist).
Application and Performance: Certification of nutrient management planners applies to all farms
and all land to which nutrients are applied. Farmers may seek certification themselves or choose
to seek assistance from certified professionals when developing their nutrient management plans.
Certification provides no direct treatment or reduction of any pollutants, but is essential to
ensuring that CNMPs developed and implemented are effective in preventing pollution.
Advantages and Limitations: Without certification, those who develop CNMPs might not have
the skills or knowledge necessary to develop cost-effective plans. This could result in both water
pollution and less-than-optimal farm profits.
'Third-party vendor certification programs may include, but are not limited to, (1) the American Society of Agronomy's certification
programs, including Certified drop Advisors (CCA) and Certified Professional Agronomists (CPAg), Crop Scientists (CPCSc), and Soil
Scientists (CPSSc) (2) land grant university certification programs (3) National Alliance of Independent Crop Consultants (NAICC); and
(4) state certification programs.
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If a producer chooses to attain certification, a time commitment is required, and training and
travel expenses may be incurred. Course fees of $25 and 1 day of time lost are considered
reasonable estimates of costs based on a review of both state training programs for nutrient
management and pesticide certification costs provided by various state extension services. The
major advantage of becoming certified is that the farmer will be able to develop his or her own
CNMPs without the need for outside technical assistance. Certification would ultimately provide
benefits with regard to time commitments, convenience, and expense.
Farmers who choose not to obtain certification will need to purchase services from those who are
certified.
Operational Factors: Producers might need to travel within their state to attain certification.
Demonstration Status: Some states already have certification programs in place for nutrient
management planning, which can provide an excellent foundation for CNMP certification
programs. In addition, USDA develops agreements with third-party vendors similar to the 1998
agreement with the Certified Crop Advisors (CCAs).
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8.4 Land Application and Field Management
Two important factors that affect nutrient loss are field application timing and application
method.
8.4.1 Application Timing
The longer manure remains in the soil before crops take up its nutrients, the more likely those
nutrients will be lost through volatilization, denitrification, leaching, erosion and surface runoff.
Timing of application is extremely important. To minimize nitrogen losses, a good BMP is to
apply manure as near as possible to planting time or to the crop growth stage during which
nitrogen is most needed. Because of regional variations in climate, crops grown, soils, and other
factors, timing considerations vary across regions.
Spring is the best time for land application to conserve the greatest amount of nutrients.
Available nutrients are used during the cropping season. Nutrient losses are still possible,
however, because the likelihood of wet field conditions may result in export by surface runoff or
leaching. Spring applications result in less time for organic decomposition of manure (an issue
for manure with a low percentage of moisture) and the release of some nutrients. Four main
considerations often prevent manure application in the spring. First, a livestock producer might
not have sufficient storage capacity for an entire year of manure and might be forced to apply at
multiple times during the year. Second, time constraints and labor availability for farmers and
applicators during the spring season make it difficult to complete manure application. Third,
time constraints are complicated further if there, are wet field conditions. Finally, applying
manure in the spring creates a potential for greater soil compaction which can cause yield loss.
Field equipment,-such as heavy manure tanks, compacts the soil and can alter soil structure and
reduce water movement. Tillage to break up this compaction is not a viable option in reduced-till
cropping systems. Freezing and thawing cycles in winter months lessen the effect of compaction
caused during fall application.
Conversely, fall application usually results in greater nutrient losses (25 to 50 percent total
nitrogen loss) than spring application, especially when the manure is not incorporated into the
soil (MWPS, 1993). These nitrogen losses are a result of ammonia volatilization and conversion
to nitrate, which may be lost by denitrification and leaching. Fall applications allow soil
microorganisms time to more fully decompose manure and release previously unavailable
nutrients for the following cropping season. This is especially advantageous for solid manure,
which contains high levels of organic matter. When temperatures are below 50 °F, microbial
action of the soil slows and prevents nitrification, thereby immobilizing some of the nutrients. In
the fall, manure is best applied to fields to be planted in winter grains or cover crops. If winter
crops are not scheduled to be planted, manure should be applied to fields that require nutrients in
the subsequent crop year or have the most existing vegetation or crop residues, or to sod fields to
be plowed the next spring. •
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Summer application is suitable for small-grain stubble, noncrop fields, or little-used pastures.
Manure can also be applied effectively to pure grass stands or to old legume-grass mixtures, but
not on young stands of legume forage. Summer application allows a farmer or applicator to
spread out the workload of a busy spring and fall.
Winter is the least desirable application time, for both nutrient utilization and pollution
prevention. Late fall or winter applications might be desirable because of greater labor
availability and better soil trafficability. Although there may be significant losses of available
. nitrogen, the organic nitrogen fraction will still contribute to the plant-available nitrogen pool.
The potential for nutrient runoff is an environmental concern for applications that cannot be
incorporated, especially during winter. Winter applications of manure should include working
the manure into the soil either by tillage or by subsurface injection, thereby reducing runoff. In
northern areas, frozen soil surfaces prevent rain and melting snow from carrying nutrients into
the soil and make incorporation and injection impossible. Where daily winter spreading is
necessary, manure should be applied first to fields that have the least runoff potential.
Application on frozen or snow-covered ground should be avoided because of the possibility of
runoff.
8.4.2 Application Methods
Manure can be handled as a liquid (less than 4 percent solids), semisolid or slurry (4 to 20
percent solids), or solid (greater than 20 percent solids). The amount of bedding and water
dilution influence the form, as do the species and production phase of the animals.
Consequently, the manure form dictates the way manure will be collected, stored, and finally
applied to land (MWPS, 1993).
Liquid manure and slurry manure are applied using similar methods, but equipment needs for the
two manure forms may vary depending on percentage of solids content. Chopper pumps may be
necessary to reduce the particle size of bedding or feed. Agitation of liquid manure is extremely
important prior to land application. Inadequate agitation results in inconsistent nutrient content
and makes the manure difficult to credit as a valuable fertilizer source. A lack of uniform
application can also lead to nutrient excesses and deficiencies, yield loss, and increased incidence
of ground and surface water contamination. Furthermore, insufficient agitation can cause a
buildup of solids in the storage tank and lead to decreased capacity. A disadvantage to liquid
manure handling systems is that they may require the addition of water for collection of the
manure, increasing the amount of material that must be handled and applied.
The liquid-based manure is applied to fields by means of tank wagons, drag-hose systems, or
irrigation systems. Tank wagons can either broadcast manure (surface apply) or inject it into the
soil. The method of injection, and the corresponding level of disturbance to the soil surface, is
extremely variable. With the proper implement type, disruption to the soil surface and residue
cover can be minimal and appropriate for reduced-tillage operations. Depending on the specific
implement chosen, injection is the preferred method in reduced-till or no-till cropping systems.
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Soil incorporation occurs immediately and crop residues are left on the surface to act as a mulch.
The amount of exposed soil surface is minimized, resulting in reduced erosion. Injection systems
can reduce odor by 20 to 90 percent (Hanna, 1998). There is less nutrient loss to air and
diminished runoff as well. For injection, a liquid manure spreader or "umbilical" system and
equipment to deposit manure below the soil surface are necessary. Injection requires more
horsepower, fuel, and time than broadcasting. Liquid-based manure can also be pumped from a
tanker or storage facility located adjacent to the field through a long flexible hose. This umbilical
or drag-hose system is feasible for both broadcasting and injecting manure. Irrigation equipment
applies liquid manure pumped directly from storage (usually lagoons). Wastewater and manure
can be applied by means of sprinkler or surface (flood) irrigation.
Solid manure is broadcast using box-type or open-tank spreaders. Spreader mechanisms include
paddles, flails, and augers. Rate calibration of box spreaders is often difficult, resulting in less
uniform application, difficulty crediting fertilizer values, nutrient excesses and deficiencies
resulting in yield loss, and increased potential for ground and surface water contamination.
Surface application, or broadcasting, is defined as the application of manure to land without
incorporation. Simply applying manure to the soil surface can lead to losses of most of the
available nitrogen, depending on soil temperature and moisture. Nitrogen is lost through
volatilization of ammonia gas, denitrification of nitrates, and leaching. Volatilization losses are
greatest with lower, humidity and with increases in time, temperature, and wind speed. High-
moisture conditions can carry water-soluble nitrates through the soil profile and out of the plant
root zone; potentially causing-ground water contamination. University extension services
generally recommend a certain correction factor (Table 8-25). Environmental conditions such as
temperature, wind, and humidity influence this factor. Generally, phosphorus and potassium
losses are negligible, regardless of application method. However, some phosphorus and
potassium is lost through soil erosion and runoff.
Table 8-25. Correction Factors to Account for Nitrogen Volatilization
Losses During Land Application of Animal Manure
Application Method
Direct injection
Broadcast and incorporation within 24 hours
Broadcast and incorporation after 24 hours
Broadcast liquid, no incorporation
Broadcast dry, no incorporation-
Irrigation, no incorporation
Correction Factor
0.98
0.95
0.80
0.75
0.70
0.60
Source: Adapted from Iowa State University Extension PM-1811, November 1999.
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Solid and liquid manures can be incorporated into the soil by tillage in a row-crop system
Incorporation increases the amount of nitrogen available for crops by limiting volatilization
demtnfication, and surface runoff. Incorporation also reduces odor and encourages
mineralization of organic nitrogen by microbial action in the soil, thereby increasing the amount
of nitrogen readily available to the plants. Although incorporation by tillage makes the nutrients
less susceptible to runoff, the resulting reduction in crop residue can increase sediment runoff. If
manure nutrients are to be fully used, incorporation should be performed within 12 to 24 hours of
land application.
8.4.3 Manure Application Equipment
Livestock producers and custom manure applicators consider six predominant criteria when
choosing an application system: (1) the amount of land to be covered/fertilized; (2) the amount of
manure to be spread; (3) water content and consistency of the manure; (4) the frequency of
application and importance of timeliness; (5) soil trafficability; and (6) distance between storage
and the field to be treated. The fundamental classes of application equipment are solid waste
spreaders, liquid waste tankers, umbilical systems, and liquid waste irrigation systems Table 8-
26 presents the advantages and disadvantages of the different application systems.
Table 8-26. Advantages and Disadvantages of Manure Application Equipment
Application
Method
Description
Advantages
Disadv
spreader
Common box spreader with
aprons, paddles, or hydraulic
push system.
Depending on size, can be
pulled by as small as a 15-hp
tractor.
Equipment readily available.
Mobile. .
Equipment relatively
inexpensive.
High solids content-allows
less total volume to be
handled.
Limited capacity. High labor
and time requirement. Fairly
difficult to achieve uniform
application. Significant
nutrient loss and odor if not
incorporated immediately.
Moderate risk of soil
compaction. Uneven
applications when conditions
are windy.
spreader
V-bottom spreader with
chains attached to a rotating
shaft to sling the manure out
of the top or side of the tank.
Can be pulled by 30- to 90-hp
tractor.
Wide, even application.
Spreads solid, frozen, chunky,
slurry, semisolid, or bedded
manure. Low maintenance
because of few moving parts.
Moderate risk of soil
compaction. Higher cost and
power requirements than box
spreader. Significant nutrient
loss and odor if not
incorporated immediately.
Uneven applications when
nditions are windv.
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Application
Method
Description
Advantages
Disadvantages
Moderate risk of soil
Hopper
spreader
V-bottom spreader with large
auger across bottom of
spreader. Manure spread by
impeller on side.
Wide, even application.
compaction. Higher cost and
power requirements than box
spreader. Significant nutrient
loss and odor if not
incorporated immediately.
Uneven applications when
conditions are windy.
Liquid (Broadcast)
Tank
spreader
Mounted tank shoots manure
in widespread pattern. Can be
on one side, both sides, or
directly behind spreader.
Also can have drop hoses.
Spreading width of 15 to 25
feet Capacity of 1,000 to
5,000 gallons.
Simple to manage. Less
costly than injectors.
Requires less horsepower than
injectors.
Great nutrient loss and odor
possibilities. Uneven
applications when conditions
are windy. Air contact results
in some nutrient loss.
High risk of soil compaction.
Tractor-
pulled
flexible
hose
(drag-hose)
Manure is pumped from the
storage facility or tanker at the
edge of the field through hose
pulled by tractor. Tractor-
mounted unit consists of pipe,
nozzle, and deflector plate.
Spread pattern similar to that
of broadcast tank spreader.
Simple design. Relatively
inexpensive. Low power
required to pull hose. Low
risk of soil compaction.
Great nutrient loss and odor
possibilities. Uneven
applications when conditions
are windy. Air contact results
in some nutrient loss.
May be limited by distance
from storage to fields and by
terrain.
Liquid (Injection)
Tank
spreader
Front- or rear-mounted tank.
Soil is opened and manure
deposited below surface by
variable methods. Capacity
of 1,000 to 5,000 gallons.
Odor is minimized. .Nutrients
not lost, to atmosphere.
Nutrients can be placed near
plant's root zone in a standing
crop. Depending on
implement type, soil surface
and residue disturbed
minimally. ___
Pulling injectors requires
more horsepower. Operation
difficult in stony soil. More
expensive than broadcasting.
High risk of soil compaction.
Increased application time as
compared with broadcasting.
Tractor-
pulled
flexible
hose
(drag-hose)
Manure is pumped from
storage facility or tanker at the
edge of the field through hose
pulled by tractor and fed into
injectors. Injectors must be
lifted from ground to turn.
Rigid, swinging pipe on
equipment prevents hose
damage by tractor. 150-to
200-hp tractor needed.
Odor controlled during
spreading. Nitrogen retained.
Requires less power than
tanker injection systems.
Low soil compaction risk.
Some manure may be spilled
at end of runs.
May be limited by distance
from the storage to fields and
by terrain.
Increased application time as
compared with broadcasting
by drag-hose.
Tme
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Application
Method
Description
Advantages
Disadvantages
Surface
irrigation
Manure transported to
application site through rigid
irrigation pipes. Manure
spread on field via gated pipes
or open ditches.
Low initial investment. Low
energy requirements. Little
equipment needed.
Little soil compaction.
Few mechanical parts.
Timely manure application.
Moderate labor requirement.
High degree of management
skill needed. Limited to
slopes of less than 2%. May
be limited by distance to field.
High odor levels possible.
Difficult to control runoff and
achieve uniform application.
Significant nutrient loss if not
incorporated immediately.
Hand-
moved
sprinklers
Manure transported through
rigid irrigation pipes,
including a mainline and one
or more aluminum pipe
laterals. One parcel irrigated
at a time. Pipe is
disassembled and moved by
hand to next parcel.
Low initial investment. Few
mechanical parts. Low power
requirement. Adapts to field
shape. Little soil compaction.
Timely manure application.
High labor requirement.
Sprinklers can clog.
Significant nutrient loss if not
incorporated immediately.
•High odor levels possible.
Uneven distribution in windy
conditions.
Towline
sprinklers
Manure transported through
rigid irrigation pipes,
including a mainline and one
or.more al
uminumpipe laterals. One
parcel irrigated at a time.
Laterals are stronger and are
moved using a tractor.
Low initial investment.
Requires less labor than, hand-
move sprinklers. Few
mechanical parts. Low power
requirement. Little soil
compaction. Timely manure
application.
Not adaptable to irregular
field shapes because of fixed
laterals. Sprinklers can clog.
Require tractor lanes for
towing in tall crops.
Significant nutrient loss if not
ihcorporated'irnmediately.
High odor possible. Uneven
distribution in windy
conditions.
Stationary
big gun
Manure transported through
rigid irrigation pipes. Single
large gun sprays manure in a
circle. Must be moved by
band.
Moderate labor requirement.
Few mechanical parts.
Adaptable to irregular land
area. Requires less pipe than
small sprinklers. Big nozzle
allows spreading of manures
with more solids. Little soil
compaction. Timely manure
application.
Moderate to high initial
investment. High power
requirement. Uneven
distribution in windy
conditions. Significant
nutrient loss if not
incorporated immediately.
High odor possible.
Towed.big
gun
Manure transported through
rigid irrigation
pipes. Functions like a
towline system with the
.aterals replaced by a big gun.
Few mechanical parts.
Requires less labor than hand-
move or stationary gun
systems. Requires less pipe
than small sprinklers. Big
nozzle allows spreading of
manures with more solids.
Little soil compaction.
Timely manure application.
Moderate to high initial
investment. High power
requirement. Uneven
distribution in windy
conditions. Less adaptable to
.and area. Requires tractor
driving lanes.
Significant nutrient loss if not
incorporated immediately.
High odor possible.
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Application
Method
Traveling
gun
Description
Manure transported through
rigid irrigation pipes.
Irrigation gun travels across
field, spreading manure in
semicircular pattern. Hard or
soft hose types available. Soft
hose system is less expensive.
Advantages
Lowest labor requirement of
all sprinkler systems. Big
nozzle allows spreading of
manures with more solids.
Little soil compaction. Less
energy required than tank
spreader. Timely manure
application.
Disadvantages
High initial costs. Maybe
limited by distance to field.
Uniform application difficult
in very windy conditions.
Possibility of high odor levels.
Significant nutrient loss if not
incorporated immediately.
Environmental damage likely
if not supervised. High odor
possible.
Sources: Adapted from MWPS, 1993, and Bartok, 1994.
Practice: Solid Manure Application with Spreaders
Description: Solid and semisolid manure can be applied to land using box, V-bottom, or flail
spreaders. Spreaders are either tractor-pulled or mounted on tracks, depending on the load.
capacity. The manure is discharged from the rear, side, or bottom of the spreader with the aid of
paddles, flails, chains, or augers (MWPS, 1993).
Application and Performance: Solid waste application methods are appropriate for manure
containing 20 percent or more solids (MWPS, 1993). Spreaders are most appropriate for smaller
operations with frequent manure removal from small areas (USDA NRCS, 1996a).
Advantages and Limitations: Spreaders aje relatively inexpensive but have a limited load ;
capacity. They require power to operate and, because of the open-air application method, often
present odor problems during and after application. In addition, calibration can be difficult and
create a problem with uniform application and nutrient crediting. Most spreaders must be filled
using a tractor front-end loader. Smaller spreaders require a greater time investment because of
the number of return trips to the manure source for refilling. Increasing spreader capacity
reduces the time investment but increases the risk of soil compaction. V-box bottom spreaders
can achieve a more uniform application than box spreaders but require more power and
investment.
Operational Factors: Spreaders are constructed of treated wood or steel and include a plastic or •
fiberglass interior lining to assist with loading and unloading. The spreaders can rot or rust,
depending on the construction material, and tractor front-end loaders can damage the spreader
and lining during loading. To prevent deterioration and damage, operators should load the
spreader carefully, clean and lubricate it regularly, and protect it from the weather.
Demonstration Status: Of grower-finisher swine operations that dispose of waste on owned or
rented land, 57.8 percent use broadcast/solid spreader methods. Only 13.7 percent of large
grower-finisher operations (marketing more than 10,000 head) use broadcast/solid spreader
methods (USDA APHIS, 1996a).
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On dairy farms with fewer than 100 milk cows, 90.6 percent broadcast manure with a solid
spreader. As herd size increases, solid handling is less common. Solid handling is most
common in the northeastern and midwestern areas of the United States (USDA APHIS, 1997).
Fewer than 1 hi 7 producers with fewer than 100 milk cows incorporates manure into soil within
24 hours of application. This ratio increases with herd size to more than one-third of producers
with more than 500 cows incorporating manure into the soil in less than 24 hours (USDA
APHIS, 1997). .
Practice: Liquid Manure Application With Tankers
Description: Manure is applied to the soil surface or injected into the soil using spreader pump
tankers or vacuum tankers. The spreader pump tanker is composed of a tank and pump mounted
on a truck or wagon and requires a separate pump to load the manure. The vacuum tanker is
mounted in a similar fashion but includes a pump that both loads and unloads the manure.
Tankers usually include an agitating device (either auger or pump type) to keep solids suspended.
Chopper pumps may be needed to prevent malfunctions caused by clogging with manure solids
or fibrous material. A gated opening at the rear bottom of the tank either discharges the manure
into a spinner for broadcasting or directs it through hoses to an injection device.
Application and Performance: Tankers are used for spreading slurry and liquid manure with less
than 10 percent solids. Tankers are appropriate for moderate- to large-sized operations.
Thorough agitation prior to and during tanker loading is necessary to limit inconsistency of
manure.
Tankers using injection systems can decrease runoff by causing minimal soil surface disturbance
and maintaining a residue cover.
Advantages and Limitations: Broadcast tankers use less power and are less expensive than
injector tankers but result in greater nutrient loss and odor problems. Tankers with injector
systems decrease the loss of nitrogen and odorous gases to the atmosphere and place nutrients
near the plant's root zone where they are needed; furthermore, depending on the specific injector
system, there is a significant decrease in disturbance to the soil surface and residue, limiting the
potential for erosion. The weight of both types of tanker spreaders can cause soil compaction.
Operational Factors: Tankers must be cleaned and repaired regularly and should be protected
from the weather. Vacuum pumps, moisture traps, pipe couplers, tires, and power shafts must be
maintained regularly. Sand, often used in dairy freestall barns, can cause damage to the pumps.
A vacuum tanker used for swine manure typically lasts 10 years (USDA NRCS, 1996a).
Demonstration Status: Slurry surface application is practiced at 46.0 percent of all grower-
finisher operations that apply wastes to land, while subsurface injection of slurry is practiced at
21.9 percent of these operations (USDA APHIS, 1996a).
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Slurry surface application is practiced at 44.6 percent of dairy farms having more than 200 milk
cows. Subsurface slurry application is practiced at only 8.6 percent of dairy operations of the
same size (USDA APHIS, 1997).
Practice: Liquid Manure Application With a Drag-Hose System
Description: The drag-hose system pumps manure from the manure storage tank, or from a
portable tank adjacent to the field, through a supply line that can be up to 3 miles long. The
supply line attaches to a flexible hose that is pulled across the field by a tractor. Manure is fed
through the hose to applicator implements similar to the types found on tankers. The manure can
be broadcast or injected.
Application and Performance: Drag-hose systems are used for spreading sluirry and liquid
manure with less than 10 percent solids. They are appropriate for moderate- to large-sized
operations. Up to 40 acres of a field can be covered before the hoses must be repositioned.
Thorough agitation prior to and during pumping is necessary to limit inconsistency of manure.
Use of certain injection systems can decrease runoff and erosion by causing minimal soil surface
disturbance and maintaining residue cover.
Advantages and Limitations: The drag-hose system eliminates the need for repeated trips/with a
wagon or tanker to the manure storage site. It takes more initial setup time, but overall it has a
smaller fuel and labor requirement than other spreader systems. Another benefit is decreased soil
. compaction and decreased road traffic. The weight of the liquid-based manure is dispersed over,
a much greater surface area and there is less equipment weight.
The person using a drag-hose system must be careful to not cut the line or break the umbilical
cord during manure application.
For application rates under or around 2,000 gallons per acre, a drag-hose may not be practical
because a certain amount of pressure is needed to keep the hose from collapsing.
Operational Factors: The application of drag-hose systems is limited by the distance the supply
lines can travel, as well as by terrain.
Demonstration Status: Drag-hose systems are becoming increasingly popular as consolidation
takes place in livestock production. It should be noted that the demonstration figures given in the
tanker section also pertain to and include swine and dairy operations using the drag-hose system
for slurry application.
Practice: Liquid Waste Application by Irrigation
Description: Irrigation systems use pipes to transfer liquid manure and wastewater from the
containment facility (usually a lagoon) to the field. Wastewater can be transferred to the field
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through portable or stationary pipes or through an open ditch with siphon tubes or gated pipe.
Manure is applied to the land using either a sprinkler or surface irrigation system.
Sprinkler systems most often used for manure disposal include handmove sprinklers, towlines,
and big guns (MWPS, 1993). Surface irrigation systems include border, furrow, corrugation,
flood, and gated pipe irrigation (MWPS, 1993). Descriptions of individual irrigation systems are
included in Table 8-26.
Application and Performance: Irrigation systems are increasingly used by hog operations that
spread over a million gallons of wastewater per year (USDA NRCS, 1996a). Most irrigation
systems can handle manure that contains up to 4 percent solids (MWPS, 1993). Solid separation
practices may be necessary to achieve this level.
Irrigation system selection varies according to the percentage of solids present in the manure, the
size of the operation, the labor and initial investment available, field topography, and crop height.
Advantages and Limitations: Irrigation systems minimize soil compaction, labor costs, and
equipment needed for large operations, and they spread the manure more quickly than tank
spreaders. Also, irrigation makes it possible to move large quantities of manure in a short time
period. Finally, irrigation systems can be used to transport water during dry periods, and they are
especially effective if crop irrigation systems are already in place.
However, nitrogen is easily lost to volatilization and denitrification if not incorporated into the
soil. Odor from thewastewater can create a nuisance. Other problems that might alter the
viability of the irrigation system include windy conditions that reduce the uniformity of spreading
and increase odor problems off-site, the fact that soils might not be permeable enough to absorb
the rapidly applied liquid, and a crop height that prevents application (MWPS, 1993; USDA
NRCS, 1996a).
Although irrigation systems can reduce the overall labor cost of large spreading operations, labor
communication and coordination are needed for initiating, maintaining, and ceasing ah irrigation
cycle. System operators must agitate manure before and during pumping to keep solids in
suspension. Surface irrigation application must be closely monitored to control runoff and
application uniformity. Pipes must be flushed with clean water after manure is applied to prevent
clogs. Irrigation pipes are susceptible to breakage and should be regularly inspected.
Operational Factors: Single-nozzle sprinklers perform better where wind is a problem. Also,
one large nozzle is less likely to plug than two smaller nozzles with the same flow capacity.
Demonstration Status: Irrigation of swine wastewater is practiced at 12.8 percent of grower-
finisher operations which dispose of then: waste on owned or rented land. Nearly 80 percent of
grower-finisher operations with more than 10,000 head use irrigation for land application of
manure.
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Land application of wastewater by irrigation is also common at large dairy operations; 40.5
percent of producers with more than 200 cows used irrigation for manure application.
Practice: Center Pivot Irrigation
Description: Center pivots are a method of precisely irrigating virtually any type of crop (with
the exception of trees) over large areas of land. In a center pivot, an electrically driven lateral
assembly extends from a center point where the water is delivered, and the lateral circles around
this point, spraying water. A center pivot generally uses 100 to more than 150 pounds of
pressure per square inch (psi) to operate and therefore requires a 30- to 75-horsepower motor.
The center pivot system is constructed mainly of aluminum or galvanized steel and consists of
the following main components:
Pivot: The central point of the system around which the lateral assembly rotates. The
pivot is positioned on a concrete anchor and contains various controls for operating the
system, including timing and flow rate. Wastewater from a lagoon, pond, or other storage
structure is pumped to the pivot as the initial step hi applying the waste to the land.
Lateral: A pipe and sprinklers that distribute the wastewater across the site as it moves
around the pivot, typically 6 to 10 feet above the ground surface. The lateral extends out
from the pivot and may consist of one or more spans depending on the site characteristics.
A typical span may be from 80 to 250 feet long, whereas the entire lateral may be as long
as 2,600 feet
Tower: A structure located at the end point of each span that provides support for the pipe.
Each tower is on wheels and is propelled by either an electrically driven motor, a
hydraulic drive wheel, or liquid pressure, which makes it possible for the entire lateral to
move slowly around the pivot.
The center pivot is designed specifically for each facility, based on wastewater volume and
characteristics, as well as site characteristics such as soil type, parcel geometry, and slope. The
soil type (i.e., its permeability and infiltration rate) affects the selection of the water spraying
pattern. The soil composition (e.g., porous, tightly packed) affects tire size selection as to
whether it allows good traction and flotation. Overall site geometry dictates the location and
layout of the pivots, the length of the laterals, and the length and number of spans and towers.
Center pivots can be designed for sites with slopes of up to approximately 15 percent, although
this depends on the type of crop cover and methods used to alleviate runoff. Figure 8-15 presents
a schematic of a central pivot irrigation system.
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Application and Performance: Using a center pivot, nutrients in the wastewater, such as nitrogen
and phosphorus, can be efficiently applied to the cropland to meet crop needs. With a known
nutrient concentration in the wastewater, the animal waste can be agronomically applied to
cropland very precisely by appropriately metering the flow based on crop uptake values.
Agronomic application helps reduce runoff of pollutants from cropland and overapplication of
nutrients to the soil.
Center pivot irrigation does not provide wastewater treatment. Nutrients, pathogens, and other
pollutants simply pass through and are distributed by the center pivot.
Figure 8-15. Schematic of a Center Pivot Irrigation System
Operational Factors: According to one manufacturer (Valley Industries), center pivot systems
can be designed to handle wastes containing up to 5 percent solids. Thus, it may be necessary to
have a solids removal step (e.g., settling basin or mechanical separator) prior to wastewater
storage and subsequent land application. It is also a good practice to flush the pipes with clean
water following waste application to prevent clogging of pipes and sprinkler nozzles.
Salt accumulation in the soil may be an issue, especially in drier climates. Salt concentrations in
the wastewater and soil should be monitored to determine if salinity is a problem at a particular
site. .
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Odor may also be a problem when using a center pivot to apply liquid animal wastewater to the •
land. However, techniques can be implemented to reduce the dispersion of the waste stream into
the wind, such as positioning the sprinklers closer to the ground, using low trajectory sprinklers,
and using low pressure sprinklers. Proper timing of application based on environmental
conditions (i.e, monitoring wind velocity and direction) can also help reduce odor problems.
Application efficiency (i.e., the percentage of the total water pumped that reaches the ground or
plant surface) depends primarily on climatic factors such as ambient temperature, relative
humidity, and wind velocity and direction. A typical application efficiency is about 90 percent,
provided that at least 1 inch of water is applied.
Advantages and Limitations: As noted above, a center pivot is an effective means of distributing
liquid animal waste and supplying nutrients to cropland at agronomic rates. The center pivot
design is fairly flexible and can be adapted to a wide range of site and wastewater characteristics.
Center pivots are also advantageous because they can distribute the wastewater quickly,
uniformly, and with minimal soil compaction. Center pivots have low operating labor costs
compared with manual application methods.
One limitation of a center pivot system is the relatively high capital investment it entails. Other
limitations may result from sloped lands, high solids content of waste, and potential odor
problems. Center pivots are also vulnerable to high winds and lightning. Additionally, swine.
waste is fairly corrosive so the waste either needs to be treated to reduce its corrosivity or system
components such as piping need to be corrosion-resistant (e.g., galvanized or lined pipe).
Another concern with center pivot spraying is nitrogen loss through volatilization,.which.is.,
estimated to be as high as 25 percent (USDA NRCS, 1996a).
Demonstration Status: Center pivots have been in operation in the United States since the l-950s.
In the 1970s, center pivots started to become popular as a means of land-applying wastewater
from municipal, industrial, and agricultural sources. Today, center pivots are widely used hi
agriculture, including land application of wastewater from swine, beef, and dairy facilities.
Practice: Calibration of Application Equipment
Description: Three conditions must be addressed to ensure that application rates are accurate
(Schmitt and Rehm, 1998). First, analysis of a properly collected manure sample is needed to
quantify nutrient content. Second, the rate of manure being applied to the field must be known
and kept constant; calibration must be conducted for all manure applications. Third, the
application or spread pattern of the manure must be uniform throughout the field:
Manure spreaders can discharge manure at varying rates, depending on forward travel speed,
power take-off speed, gearbox settings, discharge opening, width of spread, overlap patterns, and
other parameters (USDA NRCS, 1996a). Calibration defines the combination of settings and
travel speed needed to apply manure at a desired rate.
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The actual rate at which a spreader applies manure will differ from the manufacturer's estimates,
so calibration is necessary to ensure accurate manure application (Hirschi et al., 1997). Two basic
methods, the load-area method and weight-area method, can be used for calibration (USDA
NRCS, 1996a). In the load-area method, the amount of manure in a loaded spreader is measured
and the rate is determined based on the number of loads needed to cover a known area of land. In
the weight-area method, manure spread over a small surface is weighed, and the weight per unit
area is calculated. Although there are only two basic calibration methods, a variety of specific
calibration procedures are available, many of which require knowledge of the tank's or spreader's
load size (Hirschi et al., 1997).r
For solid systems, the spreader can be weighed before and after going to the field to determine the
weight of manure spread (Schmitt and Rehm, 1998). Using the width of the spread manure and
the distance traveled per load, the weight of manure applied per acre can be calculated.
Alternatively, the rate per acre can be estimated using the weight of a full load as determined with
a scale, the number of loads per field, and the field acreage. A third method is to lay a tarp or
sheet of strong plastic in a field and make a pass over it with the spreader. The manure deposited
on the tarp or sheet of plastic is then collected and weighed. Using the area of the tarp or plastic
sheet, the weight of manure applied per unit area can be determined. Because of the small area
involved in this method, there is high variability, so multiple samples should be collected.
Knowledge of the variability in application rate, however, is useful information when one
considers that uniform application is desired.
For liquid systems, calibration requires that the manure be measured in gallons per acre. The best
way to determine the volume applied is .to weigh the tank before and after spreading the manure
and then to divide by the density of liquid manure (8.3 Ib/gallon) (Schmitt and Rehm, 1998).
Combining this information with the width of the spread pattern and the distance the tank travels
before emptying the tank will provide the data necessary to determine the application rate. A
second option for liquid systems that does not involve a scale is to fill the tank, count the number
of loads applied uniformly per unit area of field, and then calculate the volume per acre using, the
known volume of a filled tank.
Manure application rates must often be adjusted to match the recommended rate (Schmitt and
Rehm, 1998). The most common method of changing the application rate is to change the speed
at which the spreader is driven across the field. Solid manure equipment may also have an
adjustment that changes the chain speed hi the box, thereby changing the application rate. Liquid
manure application equipment may have valve opening adjustments to alter the rate. Because the .
flow rate may change from the beginning to the end of a tank of liquid manure, some equipment
uses pressurized tanks, flow pumps, and newer distributor designs to address the problem of
variable flow. Once equipment is adjusted or driving rates are changed to achieve new
application rates, recalibration is necessary to maintain the accuracy in calculating application
rates.
A wide range of water measurement devices is available, including some that primarily measure
rate or volume of flow and some that primarily measure rate of flow (USDA NRCS, 1997). A
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suitable measuring device, calibrated in the laboratory or field, can be used to determine total
application volume, which, combined with the measured nutrient concentration in the applied
liquid, can be used to determine the quantity of nutrients applied to the receiving land. Dividing
the quantity of nutrients by the land acreage provides the nutrient application rate. Rain gauges
can be used in the field to check the uniformity of application of sprinkler systems.
Application and Performance: Calibration is a practice that applies to all farms and all land on
which manure is applied, and it can be performed by the producer with little training.
Calibration of manure application equipment provides no direct treatment or reduction of any
pollutants, but it is essential to accurate application of manure.
Advantages and Limitations: Calibrating manure applicators helps to ensure that applications are
adequate for crop needs, but not excessive and a source of water quality problems (USD A NRCS,
1995).
Calibration of spreaders should take less than 1 hour (Hirschi et al., 1997).
Operational Factors: Agitation of liquid manure is extremely important prior to land application.
Inadequate agitation results hi inconsistent nutrient content and makes the manure difficult to
credit accurately as a valuable fertilizer source. A lack of uniform application can also lead to
nutrient excesses and deficiencies, yield loss, and increased incidence of ground and surface water
contamination.
Solid manure is broadcast using box-type or open-tank spreaders. Spreader mechanisms include
paddles, flails, and augers. Rate calibration of box spreaders is often difficult, resulting in less
uniform application, difficulty crediting fertilizer values, nutrient excesses and deficiencies
resulting in yield loss, and increased potential for ground and surface water contamination!
Windy conditions can affect the uniformity of applications with sprinklers. System operators
must agitate manure before and during pumping to keep solids in suspension. Surface irrigation
application must be closely monitored to control runoff and application uniformity.
Demonstration Status: Calibration of manure spreaders is a topic that has been addressed in
technical guidance and extension service publications across the United States. Information
regarding the extent to which farmers calibrate manure applicators was not found, but information
regarding the extent to which manure is sampled is probably indicative of the maximum extent to
which calibration is practiced.
Manure sampling is practiced widely across the United States, but many farmers still do not test
manure or employ a nitrogen credit from manure when determining commercial fertilizer needs
(Stevenson, 1995). A 1995 survey of 1,477 swine producers showed that 92 percent of operations
had not had their manure tested for nutrients within the past 12 months (USDA NAHMS, 1999).
Approximately 6 percent had tested their manure for nutrients once during the past 12 months,
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while another 1.5 percent had tested it twice. These findings are supported by a crop nutrient
management survey in which only 2 to 17 percent of respondents in various regions stated that
they factored manure nutrient value into their nutrient management plans (Marketing Directions
1998).
Practice: Transportation of Waste Off Site
Description: Animals-at an animal. feeding.operation,generate a large amount of liquid and semi-
solid waste every day. This waste is rich in nutrients and can be applied to cropland as fertilizer.
Often, there are more nutrients present in the waste than can be used by the crops on site. In this
case, or in the case where the operation has no cropland, the waste must be transported off site to
a facility that can manage the waste properly.
Application and Performance: At an agronomic application rate, some facilities will be able to
apply all produced animal waste to on-site cropland. However, some animal feeding operations
do not have sufficient land to accommodate all of the waste on site. These facilities must
transport the waste off site using farm equipment or by hiring a contractor to haul the waste away.
Hiring a contractor,is_a-viable option for.operations that do.not have the capital to purchase then-
own trucks to haul excess waste. .
Transportation does not "treat" the waste; however, it does move the waste off the farm. By
transporting the waste off site, the operation prevents potential pollution by limiting the time that
waste remains on the feedlot, and thereby reduces the likelihood of nutrients, pathogens, and
other pollutants being carried from the stockpile by rainfall, runoff, seepage, or volatilization.
The cost of transporting waste off site is determined by the quantity and consistency of the waste
as well as the distance the waste must be transported to be managed properly. Semisolid or liquid
manure can be more expensive to haul because it requires a tanker truck for transport and is
heavier due to a higher moisture content. Solid waste is easier to handle and is therefore less
expensive to transport. Because the amount of manure transported off site is dictated by the
amount that is applied to on-site cropland, it is expected that facilities will apply semisolid waste
to fields before they apply solid waste. The distance manure must be hauled to be properly
managed depends on the proximity of crops that need additional nutrients.
Advantages and Limitations: One advantage of transportation as a waste management practice is
not having to treat and dispose of the waste on site. Excess waste at one operation can be
transported to and used as fertilizer at another operation, distributing the nutrient load among
cropland at multiple facilities. In addition, in some cases the operation owner is able to sell the
waste to a compost or fertilizer facility or another farm operation. This income can potentially
offset the" cost of the transportation.
It is important to consider the potential non-water-quality impacts that result from increased
diesel truck traffic. EPA assumes that some facilities do not currently apply at agronomic rates,
and therefore, there will be an increase in excess waste once operations begin applying
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agronomically. This increase in excess waste requires an increase in truck traffic, causing an
increase in exhaust emissions from the trucks transporting the waste.
Operational Factors: There are three operational factors considered in detennining transportation
practices: the amount of waste to be transported, type of waste to be transported (semisolid or
liquid), and the distance from the operation to the off-site destination. The amount of waste to be-
transported per year determines the size of the trucks that are required and the time that is spent
hauling the waste. The consistency of the waste determines the type of truck that is used and the
cost of handling that waste.The distance of the off-site facility from the operation determines
how far the waste must be hauled and the cost of transporting the waste. The regional location of
the operation also plays a role in detennining how frequently the waste needs to be transported
(e.g., if there are seasons in which the waste is not applied, due to climate or crop cycles).
Demonstration Status: It is not known what portion of animal feeding operations have their waste
hauled by contractors and what portion opt to own and operate then* own vehicles. It is assumed
that each operation chooses the most economically beneficial option, which hi most cases is to
contract-haul the waste off site.
Beef: Eleven percent of beef feedlots across the country currently sell excess manure waste, and
27 percent give away their manure waste. Approximately 3 percent of beef operations currently
pay to have manure waste hauled off site (USDA APHIS, 2000).
Dairy: In 1997,23 percent of dairies with more than 200 head give away some portion of their
manure waste, and 18 percent sold or received compensation for their manure waste (USDA
APHIS, 1997).
Poultry: Most poultry operations are currently transporting their waste off site. Nationwide,
broiler operations transport about 95 percent of their waste. The percentage of layer operations
transporting waste varies by region: 40 percent in the Central region, 100 percent in the Midwest
region, 75 percent in the Mid-Atlantic region, 95 percent in the Pacific region, and 50 percent hi
the South region (USDA NAHMS, 2000).
Swine: Four to six percent of swine operations currently transfer some manure off site (USDA
APHIS 1995), while 23 percentof small swine operations and 54 percent of large swine
operations do not have enough land to apply agronomically under an N-based application scenario
(Kellogg etal., 2000).
8.4.4 Runoff Control
Fields to which manure is to be applied should have an appropriate conservation management
system in place to prevent nutrients from leaving the landscape. In the event of mismanaged
manure application, such as applying manure prior to an unexpected rainfall, conservation
practices that reduce soil erosion and water runoff, including grassed waterways, sediment basins,
and buffers, can help to niinimize the transport of nutrients off-site.
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Susceptibility to erosion and the rate at which it occurs depend on land use, geology,
geomorphology, climate, soil texture, soil structure, and the nature and density of vegetation in
the area. Soil erosion can be caused by wind or water and involves the detachment of soil
particles, their transport, and their eventual deposition away from their original position.
Movement of soil by water occurs in three stages: (1) soil particles, or aggregates, are detached
from the soil surface when raindrops splash onto the soil surface or are broken loose by fast-
moving water; (2) the detached particles are removed or transported by moving water; and (3) the
soil particles fall out of suspension when the water velocity slows, and are deposited as sediment
at a new site.
Soil erosion caused by water is generally recognized in four different forms: sheet erosion, rill
erosion, ephemeral erosion, and gully erosion. Erosion occurs during or immediately after
rainstorms or snowmelt. Sheet erosion is the loss of a uniform, thin layer of soil by raindrop
splash or water runoff. The thin layer of topsoil, about the thickness of a dime, disappears
gradually, making soil loss visibly imperceptible until numerous layers are lost.
Rill erosion often occurs in conjunction with sheet erosion and is a process in which numerous
channels, a few inches deep, are formed by fast-flowing surface water. The detachment of soil
particles results from the shear stress that water exerts on the soil. The shear stress is related to
the velocity of water flow. Therefore, when water gains velocity on steeper and longer slopes, rill
erosion increases. Sheet and rill erosion carry mostly fine-textured small particles and aggregates.
Fine-textured particles contain the bulk of plant-available nutrients, pesticides, and other
absorbed pollutants because there is more surface area per given volume of soil.
Ephemeral erosion occurs when concentrated water flows through depressions or drainage areas.
The water forms shallow channels that can be erased by tillage practices. Ephemeral erosion is a
precursor to gully erosion if left untreated.
Once rills become large enough to restrict vehicular access, they are referred to as gullies. Gully
erosion results from the removal of vast amounts of topsoil and subsoil by fast-flowing surface
water through depressions or drainage areas. Gully erosion detaches and transports soil particles
that are the size of fine to medium sand. These larger soil particles often contain a much lower
proportion of absorbed nutrients, organic material, and pollutants than the fine-textured soil
particles from sheet and rill erosion.
It is not practical to prevent all erosion, but the preferred strategy is to reduce erosion losses to
tolerable rates. In general terms, tolerable soil loss, sometimes referred to as T, is the maximum
rate of soil erosion that can occur while still maintaining long-term soil productivity. These
tolerable soil loss levels determined by USDA NRCS are based on soil depth and texture, parent
material, productivity, and previous erosion rates. The levels range from 1 to 5 tons/acre/year (2
to 11 metric tons/hectare/year). The strategies for controlling erosion involve reducing soil
detachment and reducing sediment transport.
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Surface water runoff contains pollutants, including nutrients (e.g., nitrogen and phosphorous) and
some pathogens. Excessive manure application can cause increased nitrate concentration in
water. If the rate of manure application exceeds plant or crop nitrogen needs, nitrates may leach
through the soil and into ground water. Nitrates in drinking water are the cause of
methemoglobhiemia ("blue baby syndrome").
Agricultural nonpoint source pollutants, such as those contained in manure, can migrate off the
field and into surface water through soil erosion. Excessive nutrients attached to the sediment
and carried into surface water bodies can cause algae blooms, fish kills, and odors. Combinations
of BMPs can be used to protect surface water by reducing the amount of nutrient-rich sediment
that is detached and transported away from a field.
A BMP is a practical, affordable strategy for conserving soil and water resources without
sacrificing profitability. BMPs that reduce soil erosion are part of a broader integrated soil
management system that improves overall soil health and water quality. In addition, BMPs
benefit crop production in a variety of ways, such as improved drainage, improved moisture-
holding capacity, pest management, and ultimately, long-term profitability.
Runoff Control Practices
Livestock manure can be a resource if managed correctly. A large proportion of livestock manure
is returned to the land as organic fertilizer. Unfortunately, if manure is handled incorrectly, it can
become a source of pollution that ends up in streams or lakes. The nutrients in animal manure,
especially phosphorus and nitrogen, can cause eutrophication of water.
Eutrophication is a natural process that takes place in all surface water bodies. The natural
process is accelerated by increased sediment and nutrient loading in the water. It is characterized
by an aquatic environment rich in nutrients and prolific plant production (algae). As a result of
nutrient enrichment, the biomass of the water body increases and eventually produces a noxious
environment that accelerates algae growth, leading to a reduction in water quality.
The transport of manure nutrients to streams and lakes is very similar to the transport of nutrients
from commercial fertilizers. Nitrogen is water-soluble and moves largely with the flow of water.
Injecting or incorporating manure into the land however, significantly reduces the amount of
nitrogen transported with runoff. Yet nitrogen can still move with ground water or subsurface
water flow.
Reducing phosphorous levels in surface water is the best way to limit algae growth. Most of the
phosphorous transported by surface water is attached to sediment particles. Therefore, reducing
soil erosion is essential to protecting water quality.
Manure from properly managed grazing animals has little detrimental effect on water quality. In
a grazing system, 100 percent of the manure generated by the grazing animal is applied to ihe land
daily. In addition, the runoff from a well-managed grazing system carries very little sediment or
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nutrients; however, manure from feedlots or overgrazed pastures is more susceptible to runoff and
sediment delivery (Hatfield, 1998).
Practices to Reduce Soil Detachment
The most effective strategy for keeping soil on the field is to reduce soil detachment. Crop
canopy and crop residue on the soil surface protect against soil detachment by intercepting falling
raindrops and dissipating their energy. In addition, a layer of plant material on the ground creates
a thick layer of still air next to the soil to buffer against wind erosion. Keeping sufficient cover
on the soil is therefore a key factor to controlling both wind and soil erosion.
Conservation practices, such as no-tillage, preserve or increase organic matter and soil structure.
No-tillage reduces soil detachment and transport and results hi improved water infiltration and
surface stability. No-tillage also increases the size of soil aggregates, thereby reducing the
potential of wind to detach soil particles.
Combinations of the following practices can be used to effectively reduce soil detachment by
wind or water erosion:
Conservation tillage (including mulch-tillage, no-tillage, strip-tillage, and ridge-tillage)
• Cover crops
• Contour stripcropping/contour buffer strips
• Crosswind trap strips
• Crosswind ridges
• Crosswind stripcropping
• Crop rotation, including small grains, grasses, and forage legumes
Chemical fallow or no fallow
• Grassed waterways • •
• Pasture management
Shelterbelts/field windbreaks
Practices to Reduce Transport Within the Field
Sediment transport can be reduced in several ways, including the use of vegetative cover, crop
residue, and barriers. Vegetation slows runoff, increases infiltration, reduces wind velocity, and
traps sediment. Strips of permanent vegetation (e.g., contour strip cropping and contour grass
strips) slow runoff and trap sediment. Contour farming creates rough surfaces that slow surface
water velocity and reduce transport of sediment.
Reductions in slope length and steepness reduce sedunent-carrying capacity by slowing velocity.
Terraces and diversions are common barrier techniques that reduce slope length and slow, or stop,
surface runoff. .
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By decreasing the distance across a field that is unsheltered from wind, or by creating soil ridges
and other barriers, sediment transport by wind can be reduced.
Combinations of the following practices can be used to effectively reduce soil transport by wind
or water erosion:
Buffers
— Shelterbelts/field windbreaks
— Contour strip cropping/contour buffer strips
— Riparian buffers
— Filter strips
— Grassed waterways
- Field borders
— Crosswind trap strips
— Contour or cross slope farming
• Conservation tillage, (including mulch-tillage, no-tillage, strip-tillage, and ridge-tillage)
• Crop rotation including grains, grasses and forage legumes
• Chemical fallow or no fallow
• Cover crops
• Crosswind ridges
• Crosswind stripcropping
• Diversions •
• Ponds
• Sediment basins
• Terraces
Practices to Trap Sediment Below the Field or Critical Area
Practices are also typically needed to trap sediment leaving the field before it reaches a wetland or
riparian area. Deposition of sediment is achieved by practices that slow water velocity and
increase infiltration. Combinations of the following practices can be used to effectively trap
sediment below the field or critical area:
• Contour strip cropping/contour buffer strips
• Crosswind traps strips .
• Crosswind stripcropping
• Diversions
• Filter strips
• Grassed waterways
• Ponds
Riparian buffers
• Sediment basins
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Shelterbelts/field windbreaks
• Terraces
• Wetlands
Practices That Have Multiple Functions to Reduce Detachment, Transport, and Sediment
Delivery
Many conservation practices have multiple functions. Table 8-27 identifies the primary functions
of each practice.
Considerations in BMP Selection
The selection of the most effective BMPs to protect water quality depends on the objectives of the
farmer and the specific site conditions of individual fields. The best combination of BMPs for
any specific field depends on factors such as the following:
Rainfall—more rainfall means more erosion potential.
• Soil type—some soils erode more easily than others.
Length of slope—a longer slope has increased potential for erosion due to increased
runoff energy.
• Steepness of slope—steep slopes erode more easily than gradual slopes.
• Ground cover—the-more the soil is covered with protective grasses, legumes, or crop
residues, the better the erosion control.
Other factors to consider include:
• Type of farm operation
Size of the field or farm
• Nutrient levels of manure-
• Nutrient requirements of crops
Proximity to a waterway (stream, lake), water source (drinking water well), or water of the
state
• Relationship of one erosion control practice to other supporting conservation practices
• Conservation plan if required by USDANRCS
• Economic feasibility
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Table 8-27. Primary Functions of Soil Conservation Practices
Conservation Practice
Chemical fallow or no fallow
Conservation Tillage (mulch-till, ridge-
till, strip-till, and no-till)
Contour or Cross Slope
Contour Stripcropping/Contour Buffer
Strips
Cover Crops
Crop Rotation, including small grains,
grasses, and forage legumes
Crosswind Trap Strips
Crosswind Ridges
Crosswind Stripcropping
Diversions
Field Borders
Filter Strips '" '
Grassed Waterways
Ponds
Riparian Buffers
Sediment Basins
Shelterbelts/Field Windbreaks
Terraces
Wetlands
Detachment
O
x/o
X
X
X
0
O
O
X
O
Transport
O
X/O
X
X
X
X
O
O
O
X
X
X
X
X
X
X
O
X
Sedimentation
x
O
0
X
X
X
X
X
X
O
X
X
Note: X m water erosion; O s wind erosion
Agricultural nonpoint source runoff management practices that protect natural resources generally
have two principal goals: (1) to reduce runoff volume and (2) to contain and treat agricultural
runoff. An effective runoff control system meets both of these goals by integrating several
practices in a way tihat meets the needs of the particular management'system. Strategies for
controlling erosion involve reducing soil detachment, reducing sediment transport, and trapping
sediment before it reaches a water body.
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Soil erosion can be reduced by using a single conservation practice or a combination of practices.
The following section explains conservation practices that can be used separately or in
combination to reduce manure runoff and improve water quality.
Practice: Crop Residue Management
Description: Tillage operations influence the amount and distribution of plant residues on or near
the soil surface. In the past, the preferred system, conventional tillage, was designed to bury as
much residue and leave the soil surface as smooth as possible, which unfortunately led to
significant soil erosion, hi contrast, residue management systems are designed to leave residue on
top of the soil surface to increase infiltration and reduce erosion. In general, the more residue left
on the soil surface, the more protection from erosion the soil has. The amount of crop residue left
after planting depends on the original amount of residue available, the tillage implements used,
the number of tillage passes, and the depth and speed at which tillage was performed.
Crop residue management has been designated by many terms since its inception. The Natural
Resources Conservation Service (NRCS) and the Conservation Technology Information Center
(CTIC) have adopted the following terms and definitions.
• Conventional-till: Tillage types that leave less than 15 percent residue cover after
planting. Generally this involves plowing or intensive (numerous) tillage trips.
Reduced-till: Tillage types that leave 15 to 30 percent residue cover after planting.
Conservation tillage: Any tillage and planting system that leaves 30 percent, or more, of
the ground covered after planting with the previous year's crop residues. Conservation
tillage systems include mulch-till, no-till, strip-till, and ridge-till.
Mulch-till: Full-width tillage that disturbs the entire soil surface is performed
prior to and during planting. Tillage tools such as chisels, field cultivators, discs,
sweeps, or bands are used. Weed control is accomplished with herbicides and/or
cultivation.
No-till and strip-till: The soil is left undisturbed from harvest to planting except
strips up to one-third of the row width (strips may involve only residue disturbance
or may include soil disturbance). Planting or drilling is accomplished using disc
openers, coulter(s), row cleaners, in-row chisels, or roto-tillers. Weeds are
controlled primarily with herbicides. Cultivation may be used for emergency weed
control. Other common terms used to describe no-till include direct seeding, slot
planting, zero-till, row-till, and slot-till.
Ridge-till: The soil is left undisturbed from harvest to planting except for strips up
to one-third of the row width. Planting is completed on the ridge and usually
involves the removal of the top of the ridge. Planting is completed with sweeps,
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disc openers, coulters, or row cleaners. Residue is left on Hie surface between
ridges. Weeds are controlled with herbicides (frequently banded) and/or
cultivation. Ridges are rebuilt during cultivation (CTIC, 1998a).
No-till, strip-till, and ridge-till provide the most soil conservation protection.
Application and Performance: Plant residues can aid in soil erosion control. Residues can
protect the soil from the time of rowcrop harvest through the time the succeeding crop has
developed sufficiently to provide adequate canopy protection. Conservation tillage reduces soil
erosion by reducing detachment. It also reduces transport by minimi/JTig soil crusting and
increasing infiltration, which reduces runoff. The residue acts as small dams, slowing the
movement of water across the field and reducing its ability to carry soil particles.
Conservation tillage increases the size of soil aggregates, which reduces the potential of wind to
detach soil particles and thereby reduces wind erosion. The residue also slows the wind speed at
ground level, reducing its ability to carry soil particles.
Advantages and Limitations: Benefits other than soil conservation that can be gained include the
following:
• Reduced tillage costs
• Reduced labor
• Reduced runoff
• Reduced fuel use
• Reduced machinery wear
• Reduced particulate matter in air from wind erosion
• Increased soil moisture
• Improved surface water quality
• Increased water infiltration
• Decreased soil compaction
• Improved soil tilth
• Increased populations and diversity of wildlife
• Increased sequestration of greenhouse gases (carbon dioxide)
Normally, the cost of changing from a conventional tillage system to a conservation tillage system
is minimal if current equipment can be adapted. The cost of changing is associated with the
purchase of additional attachments for equipment and depends on the type of conservation tillage
to be done (no-till, ridge-till, mulch-till, and so forth). The incremental cost of these attachments
may range from $1.00 to $3.00/acre/year. However, if equipment is impossible to adapt or needs
extreme adaptations, the investment in changing to a conservation tillage system can become
significant.
Intensive overall management is critical to the success of a no-tillage or ridge-tillage system.
Constraints and challenges within the system should be considered before choosing a no-tillage or
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ridge-tillage method. The most successful system needs a strong commitment from a
knowledgeable manager. Management considerations and system constraints include the
following:
• Manure application and the need to incorporate
• Alternative methods or equipment modifications for nutrient placement
The need to apply and/or incorporate lime
• Planter and harvesting attachments need to be correctly installed and maintained
Critical timing of field operations
• Greater reliance on herbicides for weed control
• Shifts in weed populations and weed varieties
Increased nitrogen requirements due to an increase in residue that has a high carbon-to-
nitrogen ratio
• Delays hi spring field operations due to cold, wet soils .
Delayed seed germination due to cold, wet soils-
Conservation tillage can be used on cropland fields where excess sheet and rill erosion and wind
erosion are a concern. Conservation tillage is most effective when used with other supporting
" conservation practices such as grassed.waterways, contouring, and field borders.
Operational Factors: In the northern areas of the United States where soil temperatures stay
colder for longer periods of time, no-till may not be as well adapted as some of the other
conservation tillage systems. In these areas strip-till or ridge-till may be better options.
Demonstration Status: Conservation tillage is used across the United States and in conjunction
with all the major crops.
Practice: Crop Rotation
Description: Crop rotation is the practice of alternating high-residue crops with low-residue
crops on the same piece of land, from year to year. Although crop rotations can vary
significantly, a typical rotation giving significant erosion protection could include high-residue-
producing crops like small grains and hay, and low-residue-producing row crops like com and
soybeans. A typical rotation using these crops would be corn-soybeans-corn-small grain-hay-hay.
Application and Performance: The soil conservation purpose of a crop rotation is to alternate
crops that, have high erosion potential with crops that have low erosion potential because it is the
average soil loss over time that is critical. It is expected that in those years when low-residue
crops are planted, significant erosion may occur. However, in years when high-residue crops are
planted, very little erosion will occur. Therefore, the average rate of soil erosion throughout the
rotation sequence will be significantly lower than it would be if only low-residue crops had been
planted. A rotation of com-soybeans-corn-small grain-hay-hay could be expected to reduce soil
erosion by 50 percent as compared with just corn and soybeans, depending on the tillage system
(Renard et al, 1997). "
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Advantages and Limitations: Weather conditions, unexpected herbicide carryover, and marketing
considerations may result in a desire to change a scheduled crop rotation. Since most fanners
want to balance production acres of different crops, they need to have the flexibility of changing
the rotations in one field because of an unexpected condition in another field.
Operational Factors: Crop rotation can be used where sheet and rill erosion is a problem on
cropland. Crop rotation works best with other supporting conservation practices such as
conservation tillage, contouring, and grassed waterways. A market or use for the small grains or
hay is needed before farmers will adopt the use of crop rotation.
Demonstration Status: The use of crop rotations is generally adopted in those regions that have
dairy herds because of the need for hay.
Practice: Contouring and Cross-Slope Farming
Description: Contour fanning is the practice of -tilling; planting; and cultivating-crops around a
slope on a nearly level line that slowly grades water to a nonerosive area that can handle
concentrated flow. In gentle rains, the contoured rows are able to slowly grade the water to a
nonerosive area such as a grassed waterway or field border. In heavier rains, when the water runs
over the tops of the rows, the rows serve as mini-dams to slow the water. Slowing the water
allows for more infiltration of water into the soil profile and reduces sediment transport in the
field.
On some slopes, strict contour farming that results in sharp turns and endless point rows is
impractical. Farm machinery may be too large to accommodate the tight turns and numerous
point rows and increases the amount of time required to complete field operations. In this case,
an alternative to contouring is cross-slope farming, which allows greater deviation from the
contour line. Although cross-slope makes farming easier, it is generally only half as effective as
contouring in reducing soil erosion.
In some areas of the country, using a rollover plow on the contour is beneficial to turn the soil
uphill while performing conventional tillage. By using a rollover plow on the contour, soil is
mechanically moved up-slope.
To allow for the removal of water in a concentrated flow, waterways need to be seeded, or shaped
and seeded.
Application and Performance: Contouring can reduce soil erosion by 25 to 50 percent and cross-
slope farming can reduce soil erosion by 10 to 25 percent depending on slope length, slope
steepness, field roughness, and row grade (Renard et al, 1997).
Advantages and Limitations:- Because contouring and cross-slope farming slow the runoff of
water, water infiltration is increased and soil erosion is reduced. The increased water infiltration
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may also mean more available subsoil moisture during the growing season. Horsepower
requirements may also be lower when farming on the contour or cross-slope.
On longer slopes, both contouring and cross-slope farming become less effective and should then
be used in combination with a supporting conservation practice such as terraces or contour strip
cropping.
The major disadvantage of contouring, and to a lesser extent cross-slope farming, is the increased
time needed to perform the tilling, planting, spraying, cultivating, and Harvesting operations.
Contouring may require 25 to 50 percent more time as compared with farming straight rows.
Cross-slope farming may require 10 to 25 percent more time as compared to farming straight
rows. This increased time leads to higher labor, fuel, and equipment costs on a per acre basis.
Operational Factors: Contouring or cross-slope farming can be used on most slopes on which
row crops are planted.
Demonstration Status: Contouring or cross-slope farming is widely adopted across the United
States.
•Practice: Contour Stripcropping/Contour Buffer Strips
Description: Contour stripcropping is a system of growing crops in approximately even-width
strips or bands on the contour. The crops are arranged so that a strip of meadow or close-
growing crop is alternated with a strip of row crop. Contour stripcropping combines the soil-,.
protection of both contouring and crop rotation. The widths of rowcrop strips should equal the
widths of the hay or small grain strips. The strips of hay or small grain slow water flow and trap
sediment from the row crop strips above them.
Contour buffer strips can be used when a higher percentage of row crop acres are needed. A
contour buffer strip system allows for the hay or small grain strips to be narrower than the strips
of row crop. Because a^contour buffer strip system results in more row crop acres, it is less
effective than contour strip cropping in reducing soil erosion.
The strip width depends on the steepness of the slope and the management practices being used.
It is also designed to accommodate the width of equipment (planters, sprayers, and harvesters).
An even number of equipment passes along each strip improves field operation efficiency by
starting and finishing a pass at the same end of the field. Grassed field borders and grassed
waterways are an integral part of any stripcropping system. They provide access lanes and safe
areas for concentrated water runoff.
Application and Performance: Contour stripcropping is very effective in reducing sheet and rill
erosion. It can reduce soil loss by as much as 75 percent, depending on the type of crop rotation
and the steepness of the slope. Depending on the width of the grass strip and the row crop strip
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and the steepness of the slopej contour buffer strips can reduce sheet and. rill erosion by as much
as 75 percent or as little as 20 percent (Renard et al., 1997).
Advantages and Limitations: Choosing to use contour stripcropping or contour buffer strips is an
excellent conservation practice for a farmer who can use small grains or hay. Instead of planting
one entire field to small grains or hay and another entire field to row crops, strips of hay or grain
can be alternated, thereby reducing soil erosion.
Effective stripcropping systems require strips that are wide enough to be fanned efficiently. If
possible, consolidation of fields may be necessary. The major disadvantage of using contour
stripcropping or contour buffer strips as an erosion control practice is the same as that of
contouring: increased time to perform the field operations (e.g., tillage, planting, spraying, and
harvesting). These practices may require 25 to 50 percent more time than farming straight rows.
Increased time used hi field operations leads to higher labor, fuel, and equipment costs on a per
acre basis.
Operational Factors: Contour stripcropping and contour buffer strips can be used where sheet
and rill erosion are a problem in cropland, and they work best with other supporting conservation
practices such as conservation tillage and grassed waterways. The use of contour stripcropping
and contour buffer strips is practical only if there is a market or use for the small grains or hay.
Demonstration Status: The use of crop rotations is generally adopted in those regions that have
dairy herds, beef cattle, or sheep because of the need for hay.
Practice: Grassed Waterways
Description: Grassed waterways are areas planted to grass or other permanent vegetative cover
where water usually concentrates as it runs off a field. They can be either natural or man-made
channels. Grass in the waterway slows the water as it leaves the field. Grassed waterways can
serve as safe outlets for graded terraces, diversions, and contour rows. They can also serve as
passageways for water that enters a farm from other land located higher in the drainage basin.
Grassed waterways significantly reduce gully erosion and aid in trapping sediment.
Application and Performance: Grassed waterways protect the soil from erosion at points of
concentrated water flow. They are designed to safely carry runoff water from the area that drams
into them to a stable outlet. Small waterways are designed in a parabolic shape and are built wide
enough and deep enough to carry the peak runoff from a 24-hour storm that would be expected to
occur once every 10 years.
The decision to mow or not to mow grassed waterways depends on supporting conservation
practices and other management concerns. To increase the lifespan of the waterway, it is best to
mow or clip the grass in the-waterway. If grasses are allowed to grow, the flow rate of the
waterway is slowed, increasing the rate of sedimentation in the waterway, which in turn increases
the cost of maintaining the waterway. If waterways are clipped, however, water flows faster and
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the sediment is carried farther down slope before being dropped out. If manure is applied in the
waterway drainage area, grassed waterways should not be mowed. To prevent excessive
sedimentation in the unmowed waterways, other supporting conservation practices, such as
contouring, conservation tillage, or barrier systems, should be in place.
Advantages and Limitations: The goal of a waterway design is to protect against soil loss while
minimizing siltation and gullying in the waterway. Gullies can form along the side of a waterway
if the water does not enter the waterway or if the runoff spills out .of the waterway and runs
parallel to it. This can be caused by inadequate design (too shallow or too narrow) or inadequate
maintenance, and in some cases by flooding. Even under the best conditions, grassed waterways
tend to either silt in or develop channels or gullies. Timely maintenance and repairs can prevent
major reconstruction. Silt can be cleaned out and small gullies can be filled in. However, if the
waterway is damaged too badly, it will need to be completely reshaped and reseeded. Often
heavy equipment such as a bulldozer or a scraper is required.
Grassed waterways permanently take land out of cereal and row crop production, but they can be
harvested for forage production if the farmer has a use and/or market for the forage and the
equipment to harvest the forage.
The cost of waterway construction depends on the depth and width of the waterway. It ranges
from $1.50 to $3.50 per linear foot, with mulch and seed. In addition to the construction cost,
there is a maintenance cost. The cost to maintain a waterway is highly variable depending on
drainage area size, soil type, grade of the waterway, and level of control of soil erosion above the
waterway.. Some waterways can function for 10 years without maintenance, whereas others need
maintenance on a yearly basis,
Operational Factors: Grassed waterways can be used where ephemeral erosion and gully erosion
are a problem.
Demonstration Status: Grassed waterways are used across the United States and in conjunction
with all the major crops.
Practice: Terraces
Description: Terraces are earthen structures that run perpendicular to the slope and intercept
runoff on moderate to steep slopes. They transform long slopes into a series of shorter slopes.
On shorter slopes, water velocity is slower and therefore has less power to detach soil particles.
Terraces slow water, catch water at intervals down slope, and temporarily store it in the terrace
channel.
Depending on the soil type, the water can either infiltrate into the ground or be delivered into a
grassed waterway Or an underground tile. Terraces are spaced to control rill erosion and to stop
ephemeral gullying. Terrace spacing is determined by several factors, including soil type, slope,
and the use of other supporting conservation practices such as conservation tillage and crop
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rotation. When more than one terrace is placed on a hillside, it is best to construct the terraces
parallel to each other and at spacings that are multiple widths of field equipment. This approach
helps eliminate short rows and improves the efficiency of field operations.
Application and Performance: Terraces reduce the rate of runoff and allow soil particles to settle
out.
Advantages and Limitations: One of the biggest advantages of terraces is that they are permanent
conservation practices. A farmer usually does not adopt terracing one year and decide the next
year not to use it, unlike such management practices as conservation tillage or contouring, hi
almost all cases, terraces will not be removed until they have exceeded their life expectancy of 20
years.
/
A disadvantage of terraces is that they are built with heavy construction equipment and the soil
structure around the terrace can be permanently altered. Terraces are built by pushing soil, up, and
they usually require a bulldozer. Compaction on the lower side of the terrace is always a concern
and can last for years after the terrace is constructed.
Terraces can permanently remove land from production. The amount of land removed from
production depends on the terrace system installed, but it normally ranges from 0 to 5 percent of
the overall land base. The cost to install terraces ranges between $0.75 and $3.00 per linear foot,
including seeding. In many cases terraces also require either a tile line or a waterway as an outlet
for the water. The cost of installing tile can range from $.75 to $1.50 per linear foot. Waterway
costs are covered in the section on grassed waterways. It can cost in the range of $100 to $165 to
protect 1 acre of land with terraces and suitable outlets. In addition to construction costs, there
are always maintenance costs. If excessive rains occur, terraces will overtop and require
maintenance. The sediment collected in terrace channels should be cleaned out periodically, at
least every 10 years, or sooner, depending on the sedimentation rate. Maintenance also includes
removing trees and shrubs from the terrace and repairing rodent damage.
In addition to the loss of cropland and cost of construction and maintenance, terraces are laid out
on the contour, which can increase the time, fuel, and equipment costs associated with field
operations. See the section on contouring and cross-slope farming for costs associated with
contouring.
Operational Factors: Terraces can be used when sheet, rill, or ephemeral erosion are a concern.
Demonstration Status:' Terraces are widely adopted across the United States.
Practice: Field Borders
Description: A field border-is a band or strip of perennial vegetation, usually grass and/or
legume, established at the edge of a field. From a soil conservation standpoint, field borders are
used to replace end rows that run up and down a hill. Sometimes field borders replace end rows
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aU the way around the field, and other times they are used where slope length and steepness
present a concern for son erosion. Field borders can be used in fields that are contoured, cross-
sloped, contour stripcropped, contour buffer stripped, or terraced.
Application and Performance: Field borders reduce detachment, slow transport, and help reduce
sediment load in water.
Advantages and Limitations: Field borders reduce acres of cereal crops or row crops in
production. However, if the field border is planted to forage, it can be harvested, as long as the
farmer has the proper equipment and a use or market for the crop. The cost of seeding an acre of
field borders is approximately $50 to $70 per acre.
Operational Factors: Field borders can be used with all crops and in all regions of the United
States.
Demonstration Status: Field borders are commonly used as a conservation practices in
combination with other practices.
Practice: Sediment Basin
Description: A sediment basin is a barrier structure constructed to collect and store manure,
sediment, or other debris.
Application and Performance:. Sediment basins are constructed to accumulate and temporarily
store water runoff. For controlling manure runoff, sediment basins may be used in two types of
settings: to capture feedlot runoff or to capture field runoff. As runoff accumulates and water is
slowly discharged through an outlet, soil particles settle out and are trapped in the basin.
Frequently, a filter strip is positioned as a secondary treatment practice below the sediment basin
to catch the additional sediment flowing through the outlet. Sediment basins reduce the transport
of soil and manure by flowing water.
Advantages and Limitations: The construction cost of sediment basins is quite variable,
depending on the steepness of the land and the size of the drainage area flowing into the basin.
However, basins are normally a cost-effective practice to capture sediment.
On-site erosion control cannot be achieved with sediment basins, because they do little to stop
detachment and transport of soil.
Operational Factors: Sediment basins can be used with all crops and in all regions of the United
States.
Demonstration Status: Sediment basins are commonly used as a conservation practices in all
cropland systems.
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Practice: Cover Crops .
Description: A cover crop is a crop of close-growing grass, legumes, or small grain grown
primarily for seasonal protection and soil improvement. These crops are also known as green
manure crops. Cover crops are usually grown for 1 year or less, except where there is permanent
cover (e.g., orchards). They increase vegetative and residue cover during periods when erosion
energy is high, and especially when primary crops do not furnish adequate cover. Cover crops
may be established by conventional or conservation tillage (no-till or mulch-till) methods or by
aerial seeding.
Cover crops should be planted immediately after harvest of a primary crop to maximize the
erosion control benefits. Recommended seeding dates vary from year to year and depend on soil
type, local climatic conditions, field exposure, and the species of cover crop being grown.
Application and Performance: Cover crops control erosion during periods when the major crops
do not furnish adequate cover. Since cover crops provide a quick canopy, they reduce the impact
of raindrops on the soil surface, thereby reducing soil particle detachment. Cover crops also slow
the surface flow of water, reducing transport of sediment and increasing water infiltration. Cover
crops can add organic material to the soil; they improve water infiltration, soil aeration, and soil
quality. In addition, cover crops can control plant nutrients and soil moisture in the root zone. If
a legume crop is used as a cover croprit-will provide nitrogen for the next year's crop.
Actively growing cover crops use available nutrients in the soil, especially nitrogen, thus
preventing or decreasing leaching or other loss. These nutrients may then become available to the
following crop during the decaying process of the green manure.
Advantages and Limitations: Cover crops increase transpiration. In areas of the United States
where moisture is limited, cover crops may use up too much of the available soil moisture. Loss
of available soil moisture may reduce the yield of the primary crop planted after the cover crop,
reducing profits.
Preparing a seedbed and drilling in a winter cereal crop costs $40 to $45 per acre. Broadcast
seeding after harvest, followed by a tillage pass that levels the .soil surface, costs $35 per acre.
Broadcast seeding prior to harvest costs $ 15 per acre.
Operational Factors: Cover crops can be used when major crops do not furnish adequate cover
and sheet and rill erosion is a problem.
Demonstration Status: Cover crops are used throughout the United States.
Practice: Filter Strip/Riparian Buffer
Description: Filter strips are strips of grass used to intercept or trap field sediment, organics,
pesticides, and other potential pollutants before they reach a body of water.
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Riparian buffers are streamside plantings of trees, shrubs, and grasses that can intercept
contaminants from both surface water and ground water before they reach a stream.
Application and Performance: Filter strips and riparian buffers are designed to intercept
undesirable contaminants such as sediment, manure, fertilizers, pesticides, bacteria, pathogens,
and heavy metals from surface and subsurface flows of water to a waterbody. They provide a
buffer between a contaminant source and waterbodies. Buffers and filter strips slow the velocity
of water, allowing soil particles to. settle out.
Advantaged and Limitations: Buffer strips and riparian buffers reduce the acreage in cereal crops
or row crops, but they can be harvested for forage production if the fanner has a use or market for
the forage and the equipment to harvest the forage. Depending on whether the filter strip or
riparian buffer strip is seeded to grass or planted to trees, the cost of seeding can range from $50
to $500 per acre.
Operational Factors: Buffer strips and riparian buffers can be used with all crops and in all
regions of the United States.
Demonstration Status: Filter strips and riparian buffers have been widely promoted and adopted
throughout the United States with programs like the Conservation Reserve Program (CRP).
Practice: Crosswind Trap Strips, Crosswind Ridges, Crosswind Stripcropping, and
Shelterbelts/Field Windbreaks
Description: Crosswind trap strips are rows of perennial vegetation planted in varying widths and
situated perpendicular to the prevailing wind direction. They can effectively prevent wind
erosion in cropping areas with high, average annual wind speeds.
Crosswind ridges are formed by tillage or planting and are aligned across the prevailing wind
erosion direction. The ridges reduce wind velocity near the ground, and the soil particles that do
start to move are trapped in the farrows between the ridge crests.
Crosswind Stripcropping is growing crops in strips established across the prevailing wind
direction and arranged so that the strips susceptible to wind erosion are alternated with strips
having a protective cover that is resistant to wind erosion.
A shelterbelt or field windbreak is a row (or rows) of trees, shrubs, or other plants used to reduce
wind erosion, protect young crops, and control blowing snow. Shelterbelts also provide excellent
protection from the elements for wildlife, livestock, houses, and farm buildings. Field
windbreaks are similar to shelterbelts but are located along crop field borders or within the field
itself. In some areas of the country, they may also be called hedgerow plantings.
Application and Performance: These practices are designed to reduce soil erosion by increasing
the soil roughness and reducing the wind speed at the soil surface.
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Advantages and Limitations: The same practices that reduce wind erosion also reduce moisture
loss. Snow is more likely to stay on the field than to blow off, thereby increasing soil moisture.
A drawback to crosswind trap strips, shelterbelts, and field windbreaks is that they take cropland
out of production. Also, they are a physical barrier to operations such as manure application with
an umbilical cord system.
Operational Factors: These practices can be used anywhere that wind erosion is a concern in
row crops.
Demonstration Status: These practices are used where row crops are planted in the Plains states.
8-200
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CHAPTER 9
NPDES REGULATORY OPTIONS
9.0 INTRODUCTION TO NPDES PROGRAM
Under the National Pollutant Discharge Elimination System (NPDES) permit program, all point
sources that discharge pollutants to waters of the United States must apply for an NPDES permit
and may discharge pollutants only under the terms of that permit. Such permits include
nationally established technology-based effluent discharge limitations. In the absence of national
effluent limitations, NPDES permit writers must establish technology-based limitations and
standards on a case-by-case basis, based on the permit writer's best professional judgment.
In addition to the technology-based effluent limits, permits may also include water quality-based
effluent limits where technology-based limits are not sufficient to ensure compliance with the
water quality standards or to implement a Total Maximum Daily Load (TMDL). Permits may
include specific-best management practices to achieve effluent limitations, typically included as
special conditions. In addition, NPDES permits normally include monitoring and reporting
requirements, as well as standardjconditions that apply to all permits (such as duty to properly
operate and maintain equipment)? ~ ~ - - , ._
Under the existing NPDES regulations, a facility must first be defined as an Animal Feeding
Operation (AFO). An AFO is a "lot or facility" where animals "have been, are, or will be stabled
or confined and fed or maintained for a total of 45 days or more in any 12 month period" and
where "crops, vegetation, forage growth, or post-harvest residues are not sustained in the normal
growing season over any portion of the lot or facility." The existing NPDES program then has a
three-tier structure, based primarily on facility size, under which an AFO is either defined or
designated as a Concentrated Animal Feeding Operations (CAFO). The size of an AFO, based on
numbers of animals, is expressed in terms of animal units, or AU. Each major livestock type,
except poultry, is assigned a multiplication factor to determine the number of AU at the facility.
Facilities with more than 1,000 AU are automatically defined as CAFOs. Facilities with more
than 300 AU are also defined as CAFOs if they either discharge pollutants into navigable waters
through a man-made ditch, flushing system, or other similar device or discharge pollutants
directly into waters that originate outside of and pass over, across, or through the facility or come
into direct contact with the confined animals. However, no AFO is defined as a CAFO if the
facility discharges only in the event of a 25-year, 24-hour storm. Finally, where an operation does
not meet the definition of a CAFO (including those with fewer than 300 AU), the permitting
authority may still designate it a CAFO on a case-by-case basis after an inspection and based on
9-1
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the finding that the facility "is a significant contributor of pollution to the waters of the United
States."
The current NPDES permit program for CAFOs is being revised to more effectively address
water pollution problems. Currently, several scenarios are being considered to revise the
structure of the NPDES rule. EPA is also proposing changes to strengthen, clarify, and simplify
the NPDES regulation. The purpose of this section is to:
• Describe industry compliance with existing regulations
• Describe the permit scenarios under consideration
• Estimate the number of AFOs that would be affected under the different scenarios
• Estimate the administrative burden
• Describe additional changes to the NPDES regulation
• Cost these additional changes to the NPDES regulation
9.1 Industry Compliance with Existing Regulations
EPA promulgated the current NPDES regulations for CAFOs in 1976. For the purposes of this
analysis, EPA assumes that all operations are currently fully complying with the existing
regulatory program. This assumption represents the "baseline," and the costs EPA is attributing
to the proposed regulatory revisions consist of the increment between these baseline costs and the
costs of new regulatory requirements.
More specifically, EPA assumes that all operations are fully complying with the existing
regulations because they fall into one of two categories. The first category consists of those
operations that are defined or designated as CAFOs and that have in fact obtained a permit. EPA
assumes, for purposes of costing the new regulations, that these CAFOs are in full compliance
with their existing permits. The second category consists of all of the other unpermitted AFOs.
EPA assumes that these operations do not need a permit because they fall outside the definition
of a CAFO. For example, they might not meet the basic terms for being defined as a CAF'O, or
they might meet those terms but are excluded from the definition because they do not discharge
except in the event of a 25-year, 24-hour storm. This second group of operations are also
complying with the regulations in the sense that they are assumed not to be subject to the CAFO
regulations in the first instance. In reality, however, there probably are a number of unpermitted
operations that are subject to the regulations and should have a permit (for example, they
incorrectly claim they are a "no discharge" facility, as discussed in the preamble). Consequently,
EPA's assumptions are conservative: they tend to underestimate the number of facilities that
should be subject to baseline costs today as permitted facilities, and therefore they overestimate
the incremental costs of the new regulatory revisions.
This section presents EPA's approach and assumptions for identifying the population of AFOs
that are subject to permitting under the existing CAFO permitting regulations. The universe of
AFOs and CAFOs is discussed in this section by livestock category, size of operation, and
production region. EPA's assumptions about what is needed to comply with the current CAFO
9-2
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regulations are consistent with the Agency's views as stated in its 1995 CAPO guidance manual,
Guidance Manual on NPDES Regulations for Concentrated Animal Feeding Operations
(USEPA, 1995; USEPA, 1999).
To be authorized by EPA to implement the NPDES program, states must adopt requirements that
are at least as stringent as those set forth in the federal regulations. Many states have adopted
stricter requirements that either lower the size threshold for animal feedlots or require additional
controls designed to prevent water quality impairment. Note that the costs presented in Chapter
11 also account for individual state requirements that are more stringent than those of the federal
NPDES program.
9.1.1 Approach and Assumptions for Identifying AFOs That Are Currently Subject to
Regulation
The primary livestock sectors have been divided into five production regions consistent with
development of the Cost Models. The designation and use of production regions allows for the
aggregation of critical data on the number of facilities, production quantities, and financial
conditions, which might otherwise not be possible because of concerns about disclosure.' The
production regions are defined in Table 4-1.
The numbers of AFOs by livestock category, facility size, and region were generally obtained
from the 1997 U.S. Census of Agriculture, from NASS bulletins (such as Cattle: Final Estimates
and Layers), and from additional census analysis requested by EPA; they were supplemented by
data and comments from industry. See Chapter 3 for more.infbrmation on data collection. ....
Swine, layer, and dairy operation data were estimated from "farms with inventory." All other
livestock operation data were estimated from "farms with sales" and were divided by an assumed
turnover rate—broilers = 5.5, swine = 2.8, turkeys = 3, beef = variable depending on size—but
were assumed to be 2.2 for facilities with 301 to 1,000 AU. See Chapter 4: Industry Profiles for
more details regarding EPA estimates of turnovers.
Livestock numbers were converted to EPA animal units assuming 1,000 AU are equal to 2,500
swine over 55 pounds, 55,000 turkeys, 30,000 laying hens using wet manure systems, 100,000
laying hens or broilers using dry manure systems, 700 mature dairy, or 1,000 beef cattle. Where
data were not available for swine and poultry in the desired size ranges, the data were linearly
interpolated to estimate the size group needed (e.g., 301 to 1,000 AU). For the beef and dairy
sectors, the interpolation assumes for any given size range of farm, the smaller farms are the
more numerous. Table 9-1 provides a summary of the number of facilities with animal
inventories (or livestock sales as described above) by livestock sector, all production regions, and
size of operation. See Chapter 4: Industry Profiles for more details regarding EPA estimates of
numbers of farms.
Fpr example USDA Census of Agriculture data are not typically released unless there is a sufficient
number of observations to ensure confidentially. Consequently, if data were aggregated on a state basis (instead of
a regional basis), many key data points needed to describe the industry segments would be unavailable
9-3
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Table 9-1. Total 1997 Facilities With Confined Animal Inventories
by Livestock Sector and Size*
BEEF
DAIRY
SWINE
LAYERS
Region
Central
Midwest
MidAflantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
•South
Total
<300 AUs
10,000
68,340
15,370
3,940
4,350
102,000
9,690
59,680
32,490
2,870
5,000
109,730
8,270
63,750
14,950
8,270
8,270
95,240
15,460
18,600
24,610
6,950
7,500
73,120
300 to 499
AUs
110
750
90
20
30
1,000
610
860
.820
840
260-
3^390
80
540
4,990
30
180
5,820
40
100
120
30
130
420 ,
500 to 999
AUs
110
750
90
30
20
1,000
410
590
560
580
L70-
2,310 -
90
3,710 '
460
20
180
4,460
80
250
210
120
340
1,000
2:1,000 AUs
510
1,450
20
80
10
2,070
410
90
80
790
... .80-
1,450
130
2,440
1,260
20
240
3,850
70
210
120
110
130
640
9-4
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BROILERS
TURKEYS
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Grand Total
<300 AUs
3,050
7,920
5,110
1,240
3,400
20,720
2,300
4,020
3,260
1,020
1,020
10,600
420,700
300 to 499
AUs
290
140
1,440
30
2,460
4,360
30
290
360
50
80
810
15800
500 to 999
• AUs
450
160
1,720
50
3,460
5,840
40
320
380
70
100
910
12 520
^1,000 AUs
350
180
940
110
2,360
3,940
30
140
80
50
70
370
12 560
TMumoers rounded to nearest 10. Numbers may not add due to independent rounding.
The numbers in Table 9-1 must be further adjusted to account for operations that have multiple
livestock inventories (e.g., swine and layers at the same facility). EPA's analysis of 1992 Census
'data indicates that approximately 20 percent of facilities with fewer than 1,000 AU maintain
multiple animal types. Hence, the number of small and medium facilities with livestock
inventories is reduced by 20 percent to arrive at the actual number of AFOs. Thus for every 100
AFOs reported hi the Census with fewer than 1,000 AU, 20 have multiple animal types, leaving
only 80 unique facilities that are potentially permitted. For large facilities, EPA's analysis
indicates 200 facilities have multiple livestock types that have more than 1,000 AU only when all
animal types are summed; at these facilities no single animal type is present at more than 1,000
AU. A corresponding reduction in large facility numbers is necessary to arrive at the total
number of AFOs in this size category. Note this reduction in facility counts applies only to the
potential number of permits; industry costs of compliance discussed elsewhere in this document
are assessed for all animal types that might be present at a given facility.
Table 9-2 displays the adjusted total number of AFOs by livestock category, production region,
and facility size basedpn the estimates presented in Table 9-1. The adjusted numbers of AFOs
presented in Table 9-2 are used throughout this section.
9-5
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Table 9-2. Total Adjusted AFOs by Size and Livestock Sector*
SEEF
DAIRY
SWINE
LAYERS
E
BROILERS
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
<300AUs
8,000
54,660
12,290
3,150
3,480
81,580
7,750
47,750
25,990
2,300
4,000
87,780
6,620
50,990
11,960
6,620
6,620
82,810
12,370
14,880
19,690
5,560
6,000
58,500
2,440
6,340
4,090
990
2,720
16,580
300 to 499
AUs
80
600
80
20
20
800
490
690
650
670
200
2,700
60
3,990
440
30
150
4,670
30
80
90
30
100
330
230
110
1,160
20
1,970
3,490
500 to 999
AUs
90
600
70
20
20
800
330
470
450
460
140
1,850
70 '
2,970
370
10
140
3,560-
70
200
170
90
270
800
360
130
1,370
40
2,770
4,670
;>1,000 AUs
510
1,430
20
70 ,
10
2,040
400
90
80
770
80
1,420
120
. 2,400
1,240 '
20
240
4,020
70
210
110
110
130
630 '
350
180
930
100
2,320
3,880
9-6
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TURKEYS
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Grand Total
<300 AUs
1,840
3;220
2,610
820
820
9,310
336.570
300 to 499
AUs
30
240
280
40
70
660
12.650
500 to 999
AUs
30
250
310
60
80
730
* 1,000 AUs
30
140
80
50
60
360
*Numbers rounded to nearest 10. Numbers may not add due to independent rounding.
9.1.2 Livestock Categories
The following subsections describe many of the livestock categories that would be affected by
the revised rule, including beef, dairy, swine, broilers, layers, and turkeys. Operations with 300 to
999 AU may be either defined or designated as a CAFO. Operations under 300 AU must be
designated as a CAFO.
9.1.2.1 Beef
The beef industry is concentrated in the Central and Midwest production regions. Smaller
concentrations of beef feeding operations exist in the MidAtlantic, South, and Pacific production
regions. —• — -,. ™.., - ..,.,.,.— ,,.,^-,_. ... . . ._... .. ... _.,..._, . ... .
Large AFOs. All large beef AFOs are assumed to be in full compliance, being either permitted or
exempt because they have no discharges except in the event of a 25-year, 24-hour storm.
Medium AFOs. EPA assumes approximately 7 percent of medium-sized AFOs in the Midwest,
Mid Atlantic, Pacific, and South production regions are CAFOs because at direct contact with
waters of the United States (WOUS) or discharge through a man-made device (MMD); 3 percent
of the AFOs hi the Central region are CAFOs because of direct contact or discharge through
MMD (Bracht, 1999; Bryon, 1999; Wilson, 1999; Funk, 1999; Gunter, 1999). Additionally,
EPA assumes that 5 percent of all medium-size AFOs are designated as CAFOs because of the
potential to discharge based on their infrequent use of effluent control systems and the
topography of the facilities hi relation to nearby WOUS (Bredencamp, 1999; Harrelson, 1999).
EPA believes 5 percent is a conservative estimate based on how many operations should be
designated and also because many operations are hicurring costs under separate State regulatory
(non-NPDES) and voluntary programs. Thus, based on the proposed new regulations, the
formula used to estimate medium-sized facilities that are CAFOs is
(Total AFOs x percentage that meet the CAFO definition, e.g., direct contact/conveyance
via MMD) + (Total AFOs x percentage that would be designated)
9-7
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Small AFOs. EPA assumes the same estimates as in the medium size category regarding direct
contact/discharge via MMD are applied (7 and 3 percent, depending on region), however, the
potential for significant discharge is estimated at approximately 0.1 percent. In. general, EPA and
States have not focused on facilities with fewer than 300 AU. Consequently, the number of
small facilities designated as CAFOs has been very small for all livestock categories. Thus, the
calculation used to estimate small regulated facilities is
(Total AFOs x percentage with direct contact or conveyance via MMD x designation rate)
Table 9-3 presents the number of beef feeding operations estimated to be in full compliance by
region and size. These estimates were derived by multiplying numbers of AFOs by the direct
contact/conveyance and designation rates discussed above.
Table 9-3. Regulated Beef Feeding Operations by Size
Category Assuming Full Compliance*
R€&!OB
Central
Midwest
Mid Atlantic
Pacific
South
Total
Total
, 520
1,570
40-
70
10
2,210
<300AU
0 ,
0
o
0
0
0
300 to 999 AU
10
140
20
o
0
170
;>1,000 AU
, 510
1,430
.. ... 20
70
10
2,040
*Numbers rounded to nearest 10.
Estimates of .the number of facilities with direct contact or with an MMD were derived based on
conversations with USDA Extension personnel, state water quality staff, industry representatives,
and others. (Bracht, 1999; Bredenkamp, 1999; Byron, 1999; Funk, 1999; Gunter, 1999;
Harrelson, 1999; Wilson, 1999). The estimate of the number of small facilities that would be
designated CAFOs is based on best professional judgment.
9.1.1.2 Dairy
The largest number of dairies assumed to be in compliance are in the Midwest and MidAtlantic
production regions, as described in Chapter 4. Smaller numbers of dairies in compliance are
located in the Central, Pacific, and South production regions. Note that although there are more
dairies in the Midwest and MidAtlantic, the Central and Pacific regions actually have the most
large dairies.
9-8
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Large AFOs. EPA assumes all large dairy AFOs are in compliance, being either permitted or
exempt because they have no discharges except in the event of a 25-year, 24-hour storm.
Medium AFOs. The dairy industry is dominated by medium and small operations in the Midwest
and MidAtlantic regions. Many of these dairies were designed and built on or near WOUS and
therefore have direct contact; others have some type of MMD. Estimates for the percentage of
dairies hi these two regions with direct contact or.MMD range from less than 20 percent to 75
percent (Bickert, 1999; Groves, 1999; Holmes, 1999). Based on this information, it is estimated
that 40 and 50 percent of the dairies in the Midwest and MidAtlantic regions, respectively, have
direct contact or use an MMD, and are thus defined as CAFOs. In the other production regions,
10 to 20 percent of the dairies are assumed to be CAFOs because direct contact or use of an
MMD2 (Johnson, 1999). The designation rates in this size class range from 5 percent (Midwest,
MidAtlantic, Pacific) to 10 percent (Central) to 15 percent (South) (Bickert, 1999; Orth, 1999).
Small AFOs. The same estimates as in the medium size category regarding direct
contact/discharge via MMD are applied to the small category. Of these dairies, it is estimated
that less than 0.1 percent would be subject to designation as CAFOs based on their potential to
significantly contribute pollution to WOUS (designation rate = 0.1 percent). Table 9-4 provides
estimates of the number of regulated dairies by size category for the various regions under the
assumption of full compliance.
Table 9-4. Regulated Dairy Operations by Size Category Assuming
Full Compliance With Existing Regulations*
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
560
620
690
1,050
200
3,120
<300 Alls1
0
10 .
0
0
0
10
300 to 999 AUs2
160
520
610
280
120
1 690
^1000 AUs
400
90
80
770
80
1 420
'Numbers rounded to nearest 10.
9.1.2.3 Swine
The swine industry is concentrated in the Midwest and MidAtlantic production regions. The
remaining swine facilities are in the Pacific region, emergent areas in the South Central region,
and to a lesser extent in the South region.
Central = 10 percent; South and Pacific = 20 percent.
9-9
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Large AFOs. All large swine AFOs are assumed to be in compliance, being either permitted or
exempt because they have no discharges except in the event of a 25-year, 24-hour storm.
Medium AFOs. Based on contacts with USDA Extension personnel, approximately 10 percent of
facilities in this size category (across all regions) are assumed to have direct contact or use an
MMD (Greenless,1999; Steinhart, 1999); all of these facilities are defined as CAFOs.
Additionally, it is estimated (based on best professional judgment) that an additional 5 percent of
the facilities have been designated. ;
Small AFOs. Estimates from a number of USDA Extension specialists concerning direct contact
or use of an MMD by small operations range from 0 to 15 percent (Funk, 1999; Jacobson, 1999;
Steinhart^ 1999); 10 percent is assumed for all regions based on best professional judgment. Of
these facilities, it is assumed that less than 0.1 percent are designated as CAFOs. Table 9-5
provides estimates of the number of regulated swine operations by size category under
assumptions of fall compliance.
Table 9-5. Regulated Swine Operations by Size Category Assuming Frail Compliance*
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
140
3,440
1,360
30
280
5.250
<300ATJ
0
0
0
0
0
0
300 to 999 AIT
20
1,040
120
10
40
1.230
;>1000 AU
120 •
2,400
1,240
20
240
4.020
*Numbers rounded to nearest 10.
9.1.2.4 Layers
A layer operation is defined as a CAFO if it maintains more than 30,000 birds and uses a wet
manure management system (a technology that has fallen out of favor in the industry and is not
being used by new operations) or if it maintains more than 100,OQO birds using continuous
overflow watering and has the potential to discharge pollutants to WOUS. EPA recognizes that
continuous overflow watering is an outdated technology that has fallen out of favor in both the
layer and broiler industries.
Currently, as many as 60 percent of the operations in the South and Central production regions
use a wet manure handling system, whereas only 0 to 5 percent of the facilities use a wet system
in the other regions. These estimates are further discussed in Chapter 4 of this document. Of
these operations, EPA assumes the large facilities have either been defined as CAFOs and are
permitted or are in compliance, not having any discharge.
9-10
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As noted in EPA's 1995 permitting guidance, dry poultry operations are subject to the NPDES
regulations if they establish a "crude liquid manure system" by stacking manure or litter in an
outside area unprotected from rainfall and runoff. This analysis assumes that 10 percent of large
operations and 5 percent of medium operations would be defined as CAFOs for this reason. This
assumption is based on conversations with industry personnel, who indicate that layer facilities
generally have long-term (> 6 months) storage, after which the manure is either sold or land
applied (Funk, 1999; Jacobson, 1999; Patterson, 1999; Thomas, 1999; Tyson, 1999; York, 2000).
The number of regulated layer operations is presented in Table 9-6 under assumptions of full
compliance.
Table 9-6. Regulated Layer Operations by Size
Category Assuming Full Compliance*
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
110
20
10
10
300
450
<300 AU
0
0
0
0
0
0
300 to 999 ATI
60
10
10
0
220
300
>I 000 ATI
50
' 10
0
10
80
150
'Numbers rounded to nearest 10.
9.L2.5 Broilers
Broiler operations with more than 30,000 birds are defined as CAFOs only if they use a liquid
manure handling system. Because few, if any, broiler operations use a liquid manure handling
system, the only way by which a broiler operation is defined as a CAFO currently is if, through
its manure handling practices, it creates a form of liquid manure handling system (Carey, 1999).
As noted, dry poultry operations may establish a "crude liquid manure system" by stacking litter
in an outside area unprotected from rainfall or runoff. This analysis assumes that at least 10
percent of the large broiler operations and 5 percent of the medium operations stack litter
temporarily, in a manner consistent with EPA's interpretation of a liquid manure handling system
and therefore would be defined as CAFOs (York, 2000). Furthermore, it is assumed that no
broiler operations have direct contact with WOUS or an MMD (Carey, 1999; Gale, 1999; Lory,
1999; Patterson, 1999; Thomas, 1999; Tyson, 1999). No small broiler operations are assumed to
be designated as CAFOs because this size category falls below the size that would typically be of
concern to the permitting authorities. Table 9-7 presents regulated broiler operation numbers.
9-11
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9.1.2.6 Turkeys ,
EPA assumes turkey operations with more than 55,000 birds (1,000 AUs) are in compliance,
being either permitted or exempt because they have no discharges except in the event of a 25-
year, 24-hour storm. The only other turkey AFOs subject to the NPDES program are those which
discharge to WOUS. Because virtually all turkey operations use dry litter systems (Battaglia,
1999; Carey, 1999; Jones, 1999), the only operations that have the potential to discharge are
those operations which have established a liquid manure system through the use of waste
management practices that allow contact between manure and rainwater. It is estimated that 5
percent of the medium facilities in the South production region and 2 percent in the other regions
are defined as GAFOs for this reason. As with broiler operations, it is assumed that no turkey
facilities have direct contact or an MMD. Table 9-8 presents the number of turkey feeding
operations in full compliance by region and size.
Table 9-7. Regulated Broiler Operations by Size Category
Assuming Full Compliance*
Region
Central .
Midwest
MidAtlantic
Pacific
South
Total
Total
60
30
220
10
470
790
<300AU
0
o
0
0
0
0
300 to 999 ATI
30
IP
130
0
240
410
s 1.000 ATI
30
20
90
10
' , 230
380
*Numbers rounded to nearest 10.
Table 9-8. Regulated Turkey Operations by Size Category
Assuming Full Compliance*
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
30
150
90
50
70
390
<300AU
0
0
0
• o
0
0
300 to 999 ATI
0
10
10
0
10
30
>1.000 ATI
30
140
80
50
60
360
*Numbers rounded to nearest 10.
9-12
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9.1.3 Summary of Feeding Operations in Compliance by Size and Type
The estimated number of regulated animal feeding operations based on an assumption of full
compliance with the existing regulations is presented in Table 9-9.
Table 9-9. Summary of Effectively Regulated
Operations by Size and Livestock Sector*
Livestock
Beef
Dairy
Swine
Layers
Broilers
Turkeys
Total
Total
2,210
3,120
5,250
450
790
390
12.210
2,040
1,420
4,020
150
410
360
8.400
170
1,690
1,230
300
380
30
0
10
0
0
0
0
This summary of animal operations that should currently have NPDES permits does not
correspond with the number of NPDES permits issued to date. Most sources place the estimate
9lfte,number of facilities covered by NPDES permits at approximately 2,500 (SAIC, 1999).
Several reasons explain the large disparity between these numbers. First, many of the large
facilities opt out of the NPDES program because they claim they do not discharge except in the
event of a 25-year, 24-hour storm. Second, many authorized states have declined to issue NPDES
permits for CAFOs, relying instead on regulatory mechanisms other than the NPDES program to
regulate CAFOs. The balance between the NPDES program and the other state programs is
discussed in more detail in following sections.
9-2 Affected Entities Under Proposed Scenarios for Revised NPDES CAFO Rule
EPA is proposing to revise the current three-tier structure in 40 CFR 122.23 for determining
which facilities are CAFOs that are subject to NPDES requirements. Five scenarios are under
consideration. Scenarios 1 through 3 have a three-tier structure similar to the current rule. Tier 1
is 1,000 AU and greater; Tier 2 is 300 to 999 AU; Tier 3 is fewer than 300 AU. Scenarios 4a
and 4b have a two-tier structure. Under Scenario 4a, Tier 1 is 500 AU and greater; Tier 2 is
fewer than 500 AU. Under Scenario 4b, Tier 1 -is 300 AU and greater; Tier 2 is fewer than 300
AU. The following sections discuss the universe of AFOs that would be affected by the
proposed scenarios by livestock category, size of operation (which varies by scenario), and
production region. The tables for each of the scenarios give both the tier and the corresponding
9-13
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animal units. Note that Tier 1 of the three-tier structure is not the same as Tier 1 of the two-tier
structure.
9.2.1 Regulatory Scenarios
In this section EPA identifies the five regulatory scenarios for the NPDES permit rule. These
scenarios, briefly described below, consider different facility size thresholds and variations in
regulatory requirements. Under all five regulatory scenarios, the following conditions apply:
• Clarify the definition of an AFO.
• Eliminate the 25-yr/24-hr storm exemption.
• Include dry poultry operations.
Duty to apply:-If the AFO meets the definition of a CAFO, it must apply for a
permit. .
• Include stand-alone immature swine and heifer operations.
• Eliminate use of the term "Animal Unit."
• Eliminate the mixed animal multiplier.
• Include facility closure requirements.
More details on the above conditions are provided in sections 9.3 and 9.4.
9.2.2 Scenario 1: Three-Tier Structure
Scenario 1 maintains the current rule-structure but adds the conditions listed in Section 9.2.1
(eliminate 25-yr/24-hr storm exemption, include dry poultry operations, etc.). The primary effect
as far as the number of faculties which would be impacted is the addition of dry poultry
operations, stand- alone immature operations, and facilities previously exempt due to the 25-
yr/24-hr storm provisions. Tier 2 facilities would still be defined as CAFOs if pollutants are
discharged through a man-made ditch, flushing system or other similar man-made device or if
pollutants are discharged directly into WOUS that originate outside of and pass over, across, or
through the facility or otherwise come into direct contact with the animals confined in the
operation. Faculties can also be designated CAFOs if they are significant contributors of
pollutants through any other means of conveyance. Small facilities (Tier 3) can be designated
only if pollutants are discharged into navigable waters through a man-made ditch, flushing
system or other similar man-made device or pollutants are discharged directly into WOUS that
originate outside of and pass over, across, or through the facility or otherwise come into direct
contact with the animals confined in the operation. A summary of the number of AFOs that
would be defined as CAFOs under this scenario is presented in Table 9-10. In total, 16,520
facilities would have to apply for a permit under Scenario 1.
EPA assumes that nationwide there are only a small number (estimated as 10) of AFOs in Tier 3
that have been designated as CAFOs. Because Scenario 1 maintains the same conditions for
designation, EPA assumes that the same number of operations will be designated under this
9-14
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scenario. For purposes of presentation, it is assumed that five of these small CAFOs are dairies
and five are swine; in reality, they are spread across the various livestock categories.
Table 9-10. Scenario 1: Summary of AFOs by Livestock Sector
Required to Apply for Permit
Livestock Sector
Beef
Dairy
Heifers
Veal
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South -
Total
Total
CAFOs
520
1,570
40
70
10
2,210
560
620
690
1,050
200
3,120
100
90
100
200
40
530
0
0
0
20
0
20
Tier 1
(>1,000 AU)
510
1,430
20
70
10
2,040
. 400
90
80 . . '
770
80
1,420
80
20
20
160
20
300
0
0
0
10
0
10
Tier 2
(300-999 AU)
10
140
20
0
0 ,
170
160
520
610
280
120
1,690
20
70
80
40
20
230
0
0
0
10
0
10
TierS
(<300 AU)
0
0
0
0
0
0
0
5
0
0
o
5
0
0
0
0
0
0
0
0
0
0
0
0
9-15
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»
Livestock Sector
Swine
Layers
Broilers
Turkeys
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Central
Midwest
MidAtlantic
Pacific
South
Total
Grand Total
Total
CAFOs
140
3,440
1,360
30
280
. 5^250
100
230
130
120
240
820
360
180
980
100
2,560
4,180
30
150
100
40
70
390
16,520
Tierl
(>1,000 AU)
120
2,400
1,240
20
240
4,020
70
210
110
110
130
630
350
180
930
100
2,320
3,880
30
140
80 .
50
60
360
12,660
Tier 2
(300-999 AU)
20
1,040
120
10
40
1,230
30
20
20
10
100
180
10
0
50
0
240
300
0
10
20
0
10
40
3,850
Tier 3
(<300 AU)
0
5
0
0
0
5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10
*Numbers rounded to nearest 10. Numbers may not add due to independent rounding.
9-16
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9.2.3
Scenario 2: Three-Tier Structure with Revised Criteria for Defining a Middle-Tier
CAFO
Scenario 2 specifies that any Tier 2 AFO (i.e., 300 to 1,000 AU) that meets any one of the
following criteria is defined as a CAFO and is required to apply for an NPDES permit:
• Operation has insufficient storage capacity to contain all manure and wastewater
from a 25-year, 24-hour storm event. (Also see Chapter 4)
Operation has animals in direct contact with WOUS.
Operation has a feedlot or storage area within 100 feet of WOUS.
Operation has been the subject of an enforcement action in the past 5 years.
Operation does not have or is not implementing a nutrient management plan.
Operation transports manure off-site for land application and there is no nutrient
management plan at the recipient's site. This also reflects operations that do not
have any cropland, as described in Chapter 4.
The case-by-case designation of facilities as CAFOs is maintained as in Scenario 1.
Who Must Apply for a Permit
Estimating the number of total AFOs that will have to apply for a permit under Scenario 2 is
difficult because the defining criteria are not mutually exclusive (e.g., many facilities without
adequate storage may also transport manure off-site for land application, etc.). While estimates
of the individual criteria have been obtained, determining how many facilities would be.defined
as CAFOs under all of the criteria is a judgement based on available data and contacts with
industry representatives.
Tables 9-11 through 9-19 indicate the number of CAFOs that would be required to apply for a
permit, by livestock category and region. While facilities may change operating practices in
order to avoid the permit requirements, it is assumed that the following six categories of facilities
will be required to apply for a permit:
• Facilities with insufficient storage.
Facilities that have been the subject of enforcement actions in the past 5 years.
Facilities that do not have a nutrient management plan.
Facilities that transport manure off-site to land without a nutrient management
plan.
Facilities that have animals in direct contact with WOUS.
Facilities where the production areas are within 100 feet of WOUS.
Estimates of facilities that would be included because of enforcement actions in the past 5 years
were made by using data on recent enforcement actions in individual states. Data on
enforcement actions are reported in the State Compendium (SAIC, 1999). Data obtained for
eight states (Illinois, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Carolina, and
9-17 • .
-------
Ohio) indicate there were approximately 119 enforcement actions annually, or 595 when
extrapolating over a 5-year period. The total number of Tier 1 and 2 AFOs in these states is
approximately 15,380. Thus, it is estimated that nearly 4 percent (595/15,380 = 0.04) of the
AFOs had an enforcement action in the past 5 years. However, it is not known how many of the
enforcement actions were taken against Tier 2 AFOs. Further, it is not known if the eight states
are representative of the nation. Consequently, the assumption used in this analysis is that only
1 percent of the Tier 2 AFOs have been the subject of enforcement actions in the past 5 years.
Beef CAFOs required to apply for a permit are presented in Table 9-11. These include facilities
where cattle have direct contact with water, facilities that have been the subject of enforcement
actions, and facilities with insufficient waste storage. In total it is estimated that approximately
57 percent of the Tier 2 beef facilities nationwide are assumed to be defined as CAFOs under this
scenario.3 Many of the Tier 2 beef feedlots have limited controls for effluents, principally storm
water discharges, which EPA considers insufficient storage (Funk, 1999; Hanrelson, 1999). Most
of these facilities are thus defined as CAFOs because the lack of available land for manure
application and inadequate storage.
Table 9-11. Scenario 2: Beef CAFOs Required to Apply for a Permit
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
610
2,110
110
90
30
2,950
Tierl
0>1,000 AU)
510
1,430
20
70
• 10
2,040
Tier2
(300-999 AU)
100
680
90
20
20
910
TierS
«300 All)
0
0
0
0
0
0
Dairy CAFOs required to apply for a permit are presented in Table 9-12. Dairies were
historically located such that they are within 100 feet of water, especially in the MidAtlantic and
Midwest production regions. Facilities within 100 feet of water are estimated at 60 percent in the
MidAtlantic and 50 percent in the Midwest; other regions range from 15 percent (Central) to 25
percent (South) (Bickert, 1999; Groves, 1999; Johnson, 1999; Holmes, 1999). Additionally,
many of the dairies, estimated at 50 percent nationally (Bickert, 1999; Holmes, 1999), have
3 This calculation is made step by step, with each factor considered incrementally. For illustration
purposes, assume there are only two reasons why a facility would be defined as a CAFO: inadequate storage (a
characteristic of 40 percent of facilities) and close proximity to water (a characteristic of 30 percent of facilities).
Assuming there are 300 AFOs, the calculation for the number of CAFOs would be 300 * 40% = 120, plus (300-
120) x 30% = 54, for a total of 174 (120 + 54).
9-18
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inadequate manure storage. Various sources indicate that these dairies practice daily spreading
of manure (Holmes, 1999; Bickert, 1999), including applications on frozen and potentially
saturated ground. It is estimated that approximately 88 percent of the Tier 2 dairies would be
defined as CAFOs under Scenario 2.
Table 9-12. Scenario 2: Dairy CAFOs Required to Apply for a Permit
Region
Central
Midwest
MidAtlantic
Pacific
South
11===^=!.
Total
1,090 .
1,145
1,100
1,740
370
1 5.445
Tierl
f>1.000 ATI)
400
90
80
770
80
1,420
Tier 2
690
1,050
1,020
970
290
4.020
Tier3
0
5
0
0
0
5
Heifer CAFOs required to apply for a permit are shown in Table 9-13. The assumptions
regarding the percentage of dairy heifers with direct contact with water and inadequate manure
storage were based on information obtained on dairy facilities discussed above.
Table 9-13. Scenario 2: Heifer CAFOs Required to Apply for a Permit
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
=^===^=
Total
170
160
160
290
60
840
Tier 1
f>1.000 AU)
80
20
20
160
20.
300
Tier 2
90
140
140
130
40
TierS
0
0
0
0
0
Veal CAFOs required to apply for a permit are shown in Table 9-14. The assumptions regarding
the percentage of veal operations with direct contact with or a man-made conveyance to water,
facilities thathave been the subject of enforcement actions, and facilities with inadequate manure
storage were based on information obtained on beef facilities. Although EPA recognizes that the
veal feeding industry is markedly different from the beef cattle industry, little information
specific to veal is available.
9-19
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Table 9-14. Scenario 2: Veal CAFOs Required to. Apply for a Permit
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
20
20
20
40
10
110
Tierl
(>1,000 AID
- 0
0
0
10
0
10
Tier 2
(300-999 AID
20
20
20
30
10
100
TierS
«300 AU)
0
0
0
0
0
0
Swine CAFOs required to apply for a permit are summarized in Table 9-15. Only a limited
number of Tier 2 facilities are added because of inadequate storage. Nationality, it is estimated
that approximately 41 percent of the Tier 2 facilities would be defined as CAFOs, primarily
because of the lack of available land on which to apply manure and wastewater.
Table 9-15. Scenario 2: Swine CAFOs Required to Apply for a Permit
Region
Central
Midwest
MidAtlantic
Pacific
South
Total
Total
170
5,255
1,600
40
360
7425
Tier 1
- (>1,OOOAU)
120
2,400
1,240
20
240
4,020
Tier 2
(300-999 AU)
50,
2,850
360
20
120
3,400
TierS
(<300 AU)
0
5
0
0
0
5
Layer AFOs required to apply for a permit under Scenario 2 are presented in Table 9-16. Very
few of the Tier 2 facilities are located within close proximity to water (Patterson, 1999; Ernst,
1999) or have inadequate storage (Funk, 1999; Patterson, 1999). However, based on the analysis
of Census of Agriculture data summarized in Chapter 4, very few of the operations have adequate
land on which to apply manure. Consequently, 97 percent of the Tier 2 AFOs would be defined
as CAFOs under Scenario 2.
9-20
-------
Table 9-16. Scenario 2: Layer CAFOs Required to Apply for a Permit
Region
==
Central
Midwest
MidAtlantic
Pacific
Total
=^=
170
480
360
230
Tierl
Ol,000 AU)
——
70
210
110
110
Tier 2
(300-999 AU)
==
100
270
250
120
TierS
(<300 AU)
g^™
0
Broiler AFOs required to apply for a permit are presented in Table 9-17. As with layers, very
few of the operations have adequate land on which to apply manure and would be defined as
CAFOs for this reason. Regarding storage, numerous contacts indicated that storage was usually
adequate, especially since the litter is removed only on an annual basis (Malone 1999; Patterson,
1999; Ramsey, 2000). However, as some contacts indicated, there is a high incidence of
improper storage stemming from the fact that when litter is removed from the houses it may be
temporarily stacked outside prior to land application (Johnson, 1999). Nationally, an estimated
96 percent of the Tier 2 broiler facilities would be defined as CAFOs under this scenario.
Table 9-17. Scenario 2: Broiler CAFOs Required to Apply for a Permit
Region
==
Central
Total
920
Tierl
(>1,000 AU)
350
Tier 2
(300-999 Al
570
Tier3
(<300Al
0
Midwest
410
180
230
MidAtlantic
3,360
930
2,430
Pacific
160
100
60
South
6,870
2,320
4,550
Total
11,720
3,880
7,840
Table 9-18 presents the estimated number of turkey AFOs required to apply for a permit under
Scenario 2. As with other poultry operations, most of the Tier 2 turkey operations have
inadequate land on which to apply the manure. Largely because of the lack of available land
approximately 97 percent of the Tier 2 facilities are defined as CAFOs under this scenario
9-21
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Table 9-18. Scenario 2: Turkey CAFOs Required to Apply for a Permit
Region
Central
Midwest
MidAttantic
Pacific
South
Total
Total
90
620
650
150
200
1 710
Tierl
(>1,000 AU)
30
140
80
50
60
360
Tier 2
(300-999 AU)
60
480
570
100
140
1,350
TierS
r<300 AU)
0
0
0
0
0
0
A summary of all AFOs required to apply for a permit under Scenario 2 is presented in Table 9-
19.
Table 9-19. Scenario 2: Summary of CAFOs by Livestock Sector
Required to Apply for a Permit*
Livestock
Beef
Dairy
Heifers
Veal
Swine
Layers
Broilers
Turkeys
Total
2,950
5,445
840
110
7,425
1,730
11,720
1,710
31,930
Tierl
O1.000 AU)
2,040
1,420
300
10
4,020
630
3,880
360
12.660
Tier 2
GOO-999 AU)
910
4,020
540
100
3,400
1,100
7,840
1,350
19,260
TierS
f<300 AU)
0
5
0
0
5
0
0
0
10
* Numbers rounded to nearest 10
9-22
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9.2.4 Scenario 3: Three-Tier Structure with Check Box Certification Form for Middle
Tier
Under Scenario 3, the certification scenario, the definition criteria are the same as those for
Scenario 2 and the threshold is again maintained for large facilities (Tier 1). Under Scenario 3
all medium AFOs (Tier 2) are also automatically defined as CAFOs. However, operations in
Tier 2 that can certify they meet the following conditions do not have to apply for a permit:
Operation has sufficient storage capacity to contain all manure and wastewater
from a 25-year, 24-hour storm event.
Operation does not have animals in direct contact with WOUS.
Operation has a feedlot or storage area not within 100 feet of WOUS.
Operation has not been the subject of an enforcement action in the past 5 years.
• Operation has a nutrient management plan.
If operation transports manure off-site for land application, there is a nutrient
management plan at recipient's site.
Those operations in the Tier. 2 size-category that cannot certify to the conditions described above
must apply fora permit. Tier 3 operations may also be designated as CAFOs on a case-by-case
basis. The effect of this scenario is that all Tier 2 facilities (approximately 25,820) would have to
either certify or apply for a permit. Additionally, all Tier 1 facilities would have to apply for a
permit.
Who Must Certify or Apply for a Permit
The number of facilities required to certify or apply for a permit under Scenario 3 is the total of
all Tier 1 and Tier 2 facilities. .The number actually estimated to obtain a permit is the same as in
Scenario 2, and the numbers are summarized in Table 9-19. A sample certification form is
shown below.
9-23
-------
Form for Certifying Out of the Concentrated Animal Feeding Operation Provisions of the
National Pollutant Discharge Elimination System
This checklist is to assist you in determining -whether your animal feeding operation (AFO) is, or
is not, a concentrated animal feeding operation (CAPO) subject to certain regulatory provisions.
For clarification, please see the attached fact sheet.
Section 1. Determine whether your facility is an AFO.
A facility that houses animals is an animal feeding operation if animals (other than aquatic
animals) have been, are, or will be stabled or confined and fed or maintained for a total of 45
days or more in any 12-month period. Animals are not considered to be stabled or confined
•when they are in areas such as pastures or rangeland that sustain crops or forage growth during
the entire time that animals are present.
D Yes, my facUity is an AFO. PROCEED TO SECTION 2.
D No, my facility is not an AFO. STOP. YOU DO NOT NEED TO SUBMIT THIS FORM.
Section 2. Determine the size range of your AFO.
If your facility is an AFO and the number of animals is in the size range for any animal type
listed below, your facility might be a concentrated animal feeding operation.
200-700 mature dairy cattle (whether milked,or dry)
300-1000 head of cattle other than mature dairy cattle
750-2,500 swine each weighing over 25 kilograms (55 pounds)
3,000-10,000 swine each weighing under 25 kilograms (55 pounds)
30,000-100,000 chickens ,
16,500-55,000 turkeys
150-500 horses
3,000-10,000 sheep or lambs
1,500-5,000 ducks
D Mv AFO is within this size range. PROCEED TO SECTION 3.
D Mv AFO has fewer than the lower threshold number of animals for any animal type so it is
not a CAFO under this description. STOP.
n Mv AFO has more than the upper threshold number of animals for any animal type. STOP.
PLEASE CONTACT YOUR PERMTT AUTHORITY FOR INFORMATION ON HOW TO
APPLY FOR AN NPDES PERMIT.
9-24
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D
D
Section 3. Minimum Requirements
Check all boxes that, apply to your operation.
My. production area is not located within 100 feet of waters of the U.S.
There is no direct contact of animals with waters of the U.S. in the production area
D I am currently maintaining properly engineered manure and wastewater storage and
containment structures designed to prevent discharge in either a 25-year, 24-hour storm (for
beef and dairy facilities) or all circumstances (for all other facilities), in accordance with the
effluent guidelines (40 CFR Part 412).
D There are no discharges from the production area and there have been no discharges in the
past 5 years.
D I have not been notified by my state permit authority or EPA that my facility needs an
NPDES permit. •
If all of the boxes in this section are checked, PROCEED TO SECTION 4. If any box in this
section is not checked, you may not use this certification and you must apply for an NPDES
permit. STOP. PLEASE CONTACT YOUR PERMIT AUTHORITY FOR MORE
INFORMATION.
Section 4. Land Application ~ ~ -
™ £f ' °ffhe bOX6S tn SeCti°n 3 are checked> y°u mi§ht be able to certify that you are not a
CAFO on the basis of ensuring proper agricultural practices for land application of CAPO
manure: J
0 I either do not land apply manure or, if land applying manure, I have and am implementing a
certified Permit Nutrient Plan (PNP). I maintain a copy of my PNP at my facility, includiJg
records of implementation and monitoring; and
B. Check One:
D My state has a program for excess manure in which I participate.
D [Alternative 1 : I do not transfer more than 12 tons of manure to any off-site recipients unless
they have signed a certification form assuring me that they are (1) applying manure
according to proper agricultural practices; (2) obtaining an NPDES permit for discharges- or
(3) transferring manure to other non-land application uses; and]
O {Tor Alternative 2, this box is not needed] I maintain records of recipients receiving greater
than 12 tons of manure annually, including the quantity and dates transferred, and I provide
recipients an analysis of the content of the manure as well as information describing the
recipients' responsibilities for appropriate manure management. If I transfer manure or
wastewater to a manure hauler, I also obtain the name and location of the recipients of the
manure, if known.
™b0th subsection A ™d subsection B above, you may certify that you are not
PROCEED TO SECTION 5 If a box is not checked in both subsection A and
9-25
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subsection B above, you may not use this certification form. STOP. YOU MUST APPLY FOR
AN NPDES PERMIT.
Sections. Certification
I certify that I own or operate the animal feeding operation described herein and have legal
authority to make management decisions about the operation. I certify that the information
provided is true and correct to the best of my knowledge.
'I understand that in the event of a discharge to waters of the U.S.from myAFO, I must report
the discharge to the Permit Authority and apply for a permit. I will report the discharge by
phone within 24 hours, submit a written report within 7 calendar days, and make arrangements
to correct the conditions that caused the discharge.
In the event any of these conditions can no longer be met, I understand that my facility is a
CAFO and I must immediately apply for apermit. I also understand that I am liable for any
unpermitted discharges. This certification must be renewed every 5 years.
I certify under penalty of law that this document was either prepared by me or prepared under
my direction or supervision. Based on my inquiry of the person or persons who gatheried the
information, the information provided is, to the best of my knowledge and belief, true, accurate
and complete. lam aware that there are penalties for submitting false information, including the
possibility of fine and imprisonment for known violations.
Facility Name.
Signature
NameofCertifier.
Date
Check one: o owner
n operator
Name and address of other entity that exercises substantial operational control of this
CAFO:_ :
Address of animal feeding operation:.
County:.
State:.
Latitude/Longitude:.
Phone:
Email:
Name of closest waters of the U.S.:.
Distance to Waters:.
Description of closest waters: (e.g., intermittent stream, perennial stream, ground water
aquifer):____ : —
9-26
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9.2.5 Scenario 4: Two-Tier Structure
Under Scenario 4 EPA established a two-tier structure based on facility size. Tier 1 operations
must apply for a permit. Tier 2 operations may be designated CAFOs, in which case they, too,
would have to apply for a permit. Small facilities—those in Tier 2—can be designated CAFOs if
they are significant contributors of pollutants. EPA analyzed two thresholds for Scenario 4- 300
AUandSOOAU.
9.2.5.1 Scenario 4a: Two-Tier Structure at 500 AU
For Scenario 4a Tier 1 CAFOs are all operations with 500 or more AU. Tier 2 CAFOs for this
scenario are those operations fewer than 500 AU. As an alternative EPA considered Scenario 4b,
under which Tier 1 CAFOs are all operations with 300 or more AU.
The Unified AFO Strategy (hereafter called the Strategy) suggests that most facilities will have a
voluntary CNMP and that approximately 5 percent of the facilities will be covered by a permit.
The Strategy strongly promotes the use of CNMPs for AFOs as a means of protecting water
quality. The regulatory role outlined in the Strategy is for EPA to permit those facilities that pose
the greatest risk to water quality. EPA has made this determination based on the size of
operation. EPA expects, at most, that states and EPA would designate 250 Tier 2 AFOs (50 per
year) based on egregious water quality problems. EPA expects that USDA will focus on those
facilities (to obtain a CNMP) that are defined as CAFOs under the current regulations but would
no longer be defined as CAFOs and would not be designated CAFOs under the proposed
regulations. Table 9-20 presents the number of facilities that would be required to apply for an
NPDES permit under Scenario 4a.
Table 9-20. Scenario 4a: Summary of CAFOs by Livestock Sector
Required to Apply for a Permit*
Livestock Total CAFOs
Tier!
(:>500 AUs)
BEEF
Central
Midwest
MidAtlantic
Pacific
South
Total
600
2,050
90
90
30
2,860
600
2,030^.
90
90
30
2,840
Tier 2
(<500 AUs)
0
20
0
0
0
20
9-27
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»,
Total CAFOs
Tierl
(;>500 Alls)
Tier 2
(<500 AUs)
DAIRY
Central
Midwest
MidAtlantic
Pacific
South
Total •
730
630
570
1,230
220
3,380
730
560
530
1,230
220
3,270
0
70
40
0
0
110
HEIFERS
Central
Midwest
MidAtlantic
Pacific
'South
Total
150
120
120
260
50
700
150
120
120
260
50
700
0
0
o
0
0
0
VEAL
Central
Midwest
MidAtlantic
Pacific
South
Total
10
10
10
30
0
60
10
10
10
30
0
60
0 .
0
0
0
0
0
SWDfE
Central
Midwest
MidAtlantic
Pacific
South
Total
190
5,450
1,630
30
380
7,680
190
5,370
1,610
30
380
7,580
0
80
20
0
0
100
9T28
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Livestock Total CAFOs
LAYERS
Central
Midwest
MidAtlantic
Pacific ,
South
Total
BROILERS
Central
Midwest
MidAtlantic
Pacific
South
Total
TURKEYS
Central
1 Midwest
MidAtlantic
Pacific
South
Total
Tierl
OSOOAUs)
140 .
410
280
200
410
1,440
140
410
280
200
400
1,430
710
310
2,310
140
5,090
8,560
710
310
2,300
140
5,090
8,550
60
400
390
110
140
1,100
25.770
60
390
390
110
140
1,090
25,520
Tier 2
(<500AUs)
0
0
0
0
10
10
0
0
10
0
0
10
•
0
0
0
0'
0
o 1
* Numbers rounded to nearest 10.
9.2.5.2 Scenario 4b: Two-Tier Structure at 300 AU
Under Scenario 4b, EPA established a two-tier structure based on size. Tier 1 CAFOs for this
scenario are all operations with 300 or more AU. Tier 2 CAFOs for this scenario are those
operations fewer than 300 AU. Tier 1 operations must apply for a permit; Tier 2 operations may
be designated CAFOs and then would have to apply for a permit. It is anticipated that
approximately 10 Tier 2 AFOs would be designated based on egregious water quality problems.
Table 9-21 presents the number of facilities that would be required to apply for an NPDES
permit under Scenario 4b.
9-29
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Table 9-21. Scenario 4b: Summary of CAFOs by Livestock Sector
Required to Apply for a Permit
Livestock
BEEF
Central
Midwest
MidAtlantic
Pacific
South
Total
Total CAFOs
680
2,630
170
110
50
3,640
Tierl
(:>300 AUs)
680
2,630
170
110
50
3,640
Tier 2
(<300 AUs)
0
0
0
0
0
0
DAIRY
Central
Midwest
MidAtlantic
Pacific
South
Total
1,220
1,255
1,180
1,900
420
5,975
1,220
1,250
1,180
1,900 .
420
5,970
0
5
0
0
0
'5
HEIFERS
Central
Midwest
MidAtlantic
Pacific
South
Total
190
170
170
310
70
910
190
170
170
310
70
910
0
0
0
0
0
0
VEAL
Central
Midwest
MidAtlantic
Pacific
South
Total
30
30
30
60
10
160
30
30
30
60
10
160
0
0
0
0
0
0
9-30
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Livestock Total CAFOs
SWINE
Central
Midwest
MidAtlantic
Pacific
South
Total
LAYERS
Central
Midwest
MidAtlantic
Pacific
South
Total
BROILERS
Central
Midwest
MidAtlantic
Pacific
South
Total
Tierl
O300 AUs)
Tier 2
(<300 AUs)
250
9,365
2,050
60
530
12,255
250
9,360
2,050
60.
530
12,250
170
490
370
230
500
1,760
170
490
370
230
500
1,760
0
5
0
0
0
5
0
0
0
0
0
0
-
940
420
3,460
160
7,060
12,040
940
420
3,460
160
7,060
12,040
0
0
0
0
0
0
TURKEYS
Central
Midwest
MidAtlantic
Pacific
South
Total
Grand Total
90
630
670
150
210
1,090
38,490
90
630
670
150
210
1,750
38480
0
0
0
0
0
0
I
iNumDers rounded to nearest 10
9-31
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9.2.6 Summary of CAFOs Requiring Permits/Applications Under Regulatory Scenarios
Table 9-22 provides a summary of the total number of AFOs that will be required to apply for a
permit (or certify they meet certain requirements, as described in Scenario 3), under all regulatory
scenarios.
Table 9-22. Scenarios 1-4: AFOs by Livestock Sector
Required to Apply for a Permit or Certify as to Permitting Requirements Under the
Proposed Regulations
Livestock
Beef
Dairy
Heifers
Veal
Swine
Layers
Broilers
Turkeys
Total
Scenario 1
2,210
3,120
530
20
5,250
820
4,180
390
16,520
Scenario 2
2,950
5,445
840
110
7,425
1,730
11,720
- 1,710
31,930
Scenario 3
2,950
5,445
840
110
7,425
1,730
11,720
1,710 -
31,930
Scenario 4a
2,860
3,380
700
60
7,680
1,440
8,560
1,100
25,770
Scenario 4b
3,640
5,975
910
160
12,255
1,760
12,040
1,750
38,490
* Numbers rounded to nearest 10. Numbers may not add due to independent rounding.
9.3 State and Federal Administrative Costs for General and Individual Permits
States and the Federal government (EPA) incur administrative costs related to the development,
issuance, and tracking of general or individual permits. In describing these administrative costs,
this section first discusses findings regarding the Unfunded Mandates Reform Act of 1995
(UMRA). Subsequently, permitting cost estimates related to the issuance of general and
individual permits for both states and the Federal government are presented. Finally, the section
presents the total costs for both general and individual permits, for states and the Federal
government, under the regulatory scenarios being considered.
93.1 Unfunded Mandates Reform Act
Title n of UMRA, Public Law 104-4, establishes requirements for federal agencies to assess the
effects of their regulatory actions on state, local, and tribal governments and the private sector.
Under section 202 of the UMRA, EPA generally must prepare a written statement, including a
cost-benefit analysis, for proposed and final rules with Federal mandates that might result in
9-32
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costs to state, local, and tribal governments, in the aggregate, or to the private sector, of $100
million or more in any one year.
EPA has determined that the options being considered for the NPDES CAFO rule do not include
a federal mandate that might result in estimated costs of $100 million or more to State, local, or
tribal governments in the aggregate. State-incurred costs under the regulatory options being'
considered are discussed in the remaining portions of this section, along with Federal costs.
Tribal governments might also incur compliance costs; however, these costs are expected to be
modest and have not been estimated. EPA has determined that the options considered include no
regulatory requirements that might significantly or uniquely affect local governments,
9.3.2 State and Federal Administrative Unit Costs for General Permits
A general permit will require states and EPA to issue public notices, answer any public
comments received, and possibly conduct public hearings. States and EPA will also incur costs
each time a facility operator applies for coverage under a general permit because of the expenses
associated with a notice of intent. These per facility administrative costs include annual record
keeping expenses associated with tracking notices of intent and performing initial facility
inspections.
Table 9-23 provides estimates of administrative costs associated with a general permit. Unit
general permit costs for public hearings, public notifications, and response to comments were
provided by a number of state permitting branch employees (Alien, 1999; Kauz Loric, 1999).
The most pertinent of these costs came.from.the state of Maryland, which has recently developed
a general permit. Although the state of Washington also provided costs on general permit
development, the state had incurred some exceptional expenses that were deemed
unrepresentative. (The state had held 23 public meetings and had taken 4 years to answer all
comments.)
Information regarding costs (for both general and individual permits) was typically provided in.
terms of labor hours. Hours were monetized using estimated average wage rates. For states, the
annual average salary was estimated at $42,000, or $20.19 per hour assuming 2,080 work hours
per year. This rate was multiplied by 1.4 to account for benefits to obtain a final loaded hourly
wage rate of $28.27. Federal wage rates were estimated based on an annual rate of $47,891 (GS
12, Step 1), which was divided by 2,080 hours per year and then multiplied by 1.6 to account for
benefits, resulting in a final loaded hourly labor rate of $36.84 (SAIC, 2000). State costs to issue
one general permit and provide for public notification of applicants are estimated at
approximately $35,820. Federal administrative costs are higher at $40,630.
Table 9-23 presents the administrative costs associated with a general permit. Permit
development estimates were made based on the assumption that many states would adapt with
relatively minor changes to the EPA model permit. Some states have experienced much higher
costs, but that is believed to be the result of developing a permit without adapting EPA's model.
The estimated permit development costs shown in the table appropriately account for states that
9-33.
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might decide to develop a general permit independently as well as those states that will adapt
EPA's model general permit. EPA obtained public notice/response to comment estimates from
the Maryland and Washington state programs. Maryland mailed public notices to 10 papers (est.
10 hours), and responding to comments required 2 weeks of one FTE (80 hours); thus the
Maryland total is 90 hours. Washington's costs for public notice were nominal, but responding
to comments took four FTE working 25 percent for 4 years (2080 x 4). It is assumed that this
Table 9-23. Administrative Costs Associated With a General Permit
Item
Range
(hours or $)
Low High
Representative
Average
State
Cost
Federal
Cost
'!) Permit development
(2) Public notice/response to
comments
(3) Public hearing(s)
(4) Quarterly public notification
TOTAL
100 300
90 8,000
120 360
$400 $8,000
200
120
240
$4,000 .
$5,650
$3,390
$6,780
$20,000
$35,820
Review/approve notice of intent
(5) Facility inspection
1 1
$1,000 $1,000
1
$1,000
$30
$1,000
$7,370
$4,420
$8,840
$20,000
$40,630
$40
$1,000
cost was unusually high and that the Maryland experience is more representative. Public hearing
estimates were based on an estimated time per meeting of 60 hours. EPA assumed states would
have two to six meetings. Inspection costs were based on Region 6's and Texas's average costs
per inspection of $1,000. EPA estimates 10 percent of facilities will be inspected. Hourly costs
were monetized using a loaded rate of $28.27 per hour. This rate is based on $42,000 (1999
dollars) per year or $20.19/hour assuming 2,080 work hours multiplied by 1.4 to account for
benefits. All costs were rounded to the nearest $10. Federal costs were based on $46,744/year
(GS 12, Step 1, 1999), divided by 2,080 hours, then multiplied by 1.6 to account for benefits,
resulting in a final loaded hourly labor rate of $36.84 (SAIC, 2000).
9-34
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9.3.3 State and Federal Administrative Unit Costs for Individual Permits
Table 9-24 shows the administrative costs associated with individual permits for both states and
the Federal government. Obtaining an individual permit requires a state or EPA to review the
permit application, provide public notice,, and possibly respond to public comments. In a
percentage of cases (estimated in this analysis at 12 percent based on conversations with
permitting authorities in Kansas, Indiana, Missouri, Ohio, and Wisconsin), a public hearing
might be necessary. Additionally, an initial facility inspection might be necessary, estimated to
cost the state or EPA approximately $1,000. Unit individual permit costs for permit review,
public hearings, and inspections were provided by several state permitting branch contacts who
issue individual permits (Clark, 1999; Foley, 1999; Nicholson, 1999; league, 1999).
Additionally, public hearing costs were based on information obtained from general permit costs.
EPA used response-to-comments estimates from Kansas. Kansas estimates 2 to 3 FTEs
dedicated to responding to comments, or from 4,160 to 6,240 hours divided by 50 to 100 permits
per year. Washington provided hearing estimates, which indicated each hearing required
approximately 100 to 150 hours of State employee time. Using best professional judgment, EPA
assumes 1 to 2 public meetings or hearings per permit at 100 to!50 hours per hearing. The
percentage of applications requiring a hearing is based on data from Kansas (4 to 8 percent) and
Indiana (15 to 20 percent). EPA based the average cost per inspection of $1,000 on data from
Region 6 and Texas. EPA estimates 10 percent of facilities will be inspected.
Table 9-24. Administrative Costs Associated with an Individual Permit
Item
Range
(hours)
Low
_ Representative State Federal
High Average Cost Cost
INDIVIDUAL PERMIT COST CATEGORIES FOR EACH FACILITY COVERED
(1) Permit review/public
notification/response to comments 60 80
(2) Public hearing
(3) Percent of applications requiring
hearing
Aye. Public Hearing Cost/Permit
TOTAL
(4) Inspections
100
4
300
20
70 $1,980 $2,580
200
12
$680 $880
$2,660 $3,460
$1,000 $1,000
$1,000
9-35
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9.4 State and Federal Administration Costs bv Regulatory Scenario
In this subsection, the estimated state and Federal permit administrative costs discussed in section
9.3 are applied to the number of livestock facilities that will be permitted or certified as described
in section 9.2. The resulting costs are presented by the five regulatory scenarios.
In determining the total costs for each scenario, note that 70 percent of all permits issued were
assumed to be general permits and the remaining 30 percent were assumed to be individual; EPA
notes this is a somewhat heavier reliance on general permits than has historically been the case,
but believes the trend toward general permits for the vast majority of CAFOs will continue. EPA
estimates facility inspections are necessary for 10 percent of all permit applications. Finally, note
that the 42 NPDES-authorized states were assumed to account for 96 percent of the total permits
issued.4 AU'costs are armualized using a 7 percent discount rate over a period of 5 years.
/
9.4.1 Scenario 1: State and Federal Administrative Costs for General and Individual
Permits
Table 9-25 presents the breakout of state administrative costs for general and individual permits,
and Table 9-26 shows Federal permit costs; both tables represent administrative costs for
regulatory Scenario 1. Total administrative permitting costs over the 5-year permitting cycle are
estimated at about $16.1 million for states and $1.1 million for the Federal government.
Annualized costs are estimated at $3.9 million for the states and $0.3 million for the Federal
government. The 16,520 total CAFOs permitted under Scenario 1 consist of 11,100 general
(NOI) permits and 4,760 individual permits for a State total of 15,860, plus 460 general (NOT)
permits and 200 individual permits for a Federal total of 660.
4 The AFOs located in the eight states that do not have NPDES authorization for their CAFO programs
account for less than 4 percent of the national total.
9-36
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Table 9-25. State Administrative Costs Under Scenario 1
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRANDTOTAL
ANNUALIZED TOTAL
Unit Cost
$35,820
$30
$1,000
$2,660
$1,000
Number
Red
• 42
11,100
1,110.
4,760
476
Total Cost
$1,504,440
$333,000
$1,110,000
$2,947,440
$12,661,600
$476,000
$13,137,600
$16,085,040
$3 922 990
, Table 9-26. Federal Administrative Costs Under Scenario 1
Number
Unit Cost Required Total flnst
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
$40,630 , 8 $325,040
$40 460 $18,400
$1,000 46 $46,000
$389,440
$3,460 200 $692,000
$1,000 20 $20,000
$712,000
$1,101,440
$268 630
9-37
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9.4.2 Scenario 2: State and Federal Administrative Costs for General and Individual
Permits
Scenario 2 requires that all Tier 1 facilities apply for an NPDES permit. AFOs in Tier 2 that meet
specific criteria (insufficient waste storage capacity, direct contact with water, past violation, etc.)
are defined as CAFOs and are required to apply for a permit. Both Tier 1 and Tier 2 facilities
would be issued permits except in those cases (assumed to be infrequent) when an operation can
demonstrate that it has "no potential to discharge." EPA estimates that a total of 31,930 facilities
will be required to apply for a permit because of discharges or potential to discharge from the
feeding operation itself or because of improper management of manure or wastewater.
Under Scenario 2, states may incur costs associated with permitting—both general and individual
permits—of approximately $29.7 million, as shown in Table 9-27. Additionally, the Federal
government is expected to spend approximately $1.7 million to permit CAFOs under Scenario 2,
as shown in Table 9-28. Annualized costs to states are approximately $7.2 million and costs to
the Federal government are $0.4 million. The 31,930 total CAFO permits under Scenario 2
consist of 21,460 general (NOI) permits and 9,190 individual permits for a State total of 30,650,
plus 900 general (NOI) permits and 380 individual permits for a Federal total of 1,280.
Table 9-27. State Administrative Costs Under Scenario 2
Number
Unit Cost Req. Total Cost
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
$35,820
42
$30 21,460
$1,000 2,146
$2,660
$1,000
9,190
919
$1,504,440
$643,800
$2.146,000
" $4,294,240
$24,445,400
$919,000
$25,364,400
$29,658,640
$7,233,470
9-38
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Table 9-28. Federal Administrative Costs Under Scenario 2
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
Unit Cost
$40,630
$40
$1,000
$3,170
$1,000
Number
8
900
90
380'
38
$325,040
$36,000
$90.000
$451,040
$1,204,600
$38,000
$1,242,600
$1,693,640
$413 060
9.4.3 Scenario 3: State and Federal Administrative Costs for General and Individual
Permits
Under Scenario 3, the certification scenario, facilities in Tier 1 are CAFOs and, as described
above, must obtain a permit unless they have demonstrated no potential to discharge. All Tier 2
AFOs are also initially defined as CAFOs and must either certify they do not meet specific
conditions to be a CAFO or obtain a permit. Designated Tier 3 facilities must also obtain a
permit. EPA estimates that a total of 38,490 facilities will be required to apply for a permit or
certify that they do not meet the criteria specified in the scenario. For purposes of estimating
administrative costs it is assumed that 31,930 facilities will actually obtain a permit.
Tables 9-29 and 9-30 present the estimated state and Federal administrative costs to permit
CAFOs under Scenario 3. States will experience costs of approximately $29.8 million or $7.3
million annualized. The Federal government is estimated to incur approximately $1.7 million in
costs or $0.4 million annualized to permit facilities under this scenario. The combined total
number of CAFOs either certifying or obtaining permits is 38,490. The 31,930 total CAFO
permits under Scenario 3 consist of 21,460 general (NOI) permits and 9,190 individual permits
for a State total of 30,650, plus 900 general (NOI) permits and 380 individual permits for a
Federal total of 1,280.
9-39
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Table 9-29. State Administrative Costs Under Scenario 3
CERTIFICATION COSTS
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
Unit Cost
$30
$35,820
$30
$1,000
$2,660
$1,000
Table 9-30. Federal Administrative Costs
CERTIFICATION COSTS
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
Unit Cost
$40
$40,630
$40
$1,000
$3,170
$1,000
Number
Req.
6,300
42
21,460
2,146
9,190
919
Total Cost
$189,000
$1,504,440
$643,800
$2.146,000
$4,483,240
$24,445,400
$919,000
$25,364,400
$29,847,640
$7,279,560
Under Scenario 3
Number
Req.
260
8
900
90
380
38
Total Cost
$10,400 1
$325,040
$36,000
$90,000
$461,440
$1,204,600
$38,000
$1,242,600
$1,704,040
$415,600
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9.4.4
Scenario 4: State and Federal Administrative Costs for General and Individual
Permits
Under Scenario 4a, facilities in Tier 1 are CAFOs and must obtain a permit as described above
. Designated Tier 2 facilities, estimated at 250, must also obtain a permit. In total it is estimated
that 25,770 facilities will be required to apply for a permit. Tables 9-31 and 9-32 present the
estimated state and Federal administrative costs to permit CAFOs under regulatory Scenario 4a
Pi™5'7,70-*0**1 CAF°S Pennitted ^"fcr Scenario 3 consist of 17,320 general (NOI) permits and
7,420 individual permits for a State total of 24,740, plus 720 general (NOI) permits and 310
individual permits for a Federal total of 1,030.
Under Scenario 4b, facilities in Tier 1 are CAFOs and must apply for a permit as described
above. Designated Tier 2 CAFOs must also obtain a permit. EPA estimates that a total of 38 490
facilities will be required to apply for a permit. Tables 9-33 and 9-34 present the estimated state
and Federal administrative costs to permit CAFOs under regulatory Scenario 4b. The 38 490
total CAFO permits under Scenario 4b consist of 25,870 general (NOI) permits and 11 080
individual permits for a State total of 36,950, plus 1,080 general (NOI) permits and 460
individual permits for a Federal Total of 1,540.
Table 9-31. State Administrative Costs Under Scenario 4a
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
fnspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
hspections .
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
Number
$35,820 42 $1,504,440
$30 17,320 $519,600
$1,000 1,732 $1,732,000
$3,756,040
$2,660 7,420 $19,737,200
$1,000 742 $742,000
$20,479,200
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Table 9-32. Federal Administrative Costs under Scenario 4a
jNumoer
Unit Cost Reg. Total Cost
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs.
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
$40,630
$40
$1,000
8
720
72
$325,040
$28,800
$72,000
$3,170
$1,000
310
31
$425,840
$982,700
$31,000
$1,013,700
$1,439,540
$351,090
Table 9-33. State Administrative Costs under Scenario 4b
Number
Unit Cost Req.
Total Cost
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
AAnMTTAT.T7.FT) TOTAL
$35,820 42 $1,504,440
$30 25,870 $776,100
$1,000 2,587 $2.587.000
$4,867,540
$2,660 11,080 $29,472,800
$1,000 1,108 . $1,108,000
$30,580,800
$35,448,340
$8,645,520
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Table 9-34. Federal Administrative Costs Under Scenario 4b
GENERAL PERMIT COSTS
General Permit Development Costs
General Permit Tracking Costs
Notification of Intent
Inspections ~ ~
Total General Permit Costs
INDIVIDUAL PERMIT COSTS
Permit Review/Approval
Inspections
Total Individual Permit Costs
GRAND TOTAL
ANNUALIZED TOTAL
Unit Cost
$40,630
$40
$1,000
$3,170
$1,000
Number
Req.
8
1080
108
460
46
$325,040
$43,200
$108,000
$476,240
$1,458,200
$46,000
$1,504,220
$1,980,440
$483,010
9.4.5 Summary of State and Federal Administration Costs by Regulatory Scenario
Total annualized state and Federal administrative expenses for permitting CAFOs vary from
approximately $4.2 million under Scenario 1 to $9.1 million under Scenario 4b (see Table 9-35).
Under-the-mbst inclusive permitting scenario, State costs do not exceed $8.7 million per year
annualized, which is well below the $ 100 million threshold for UMRA.
Table 9-35. Total Annualized State and Federal Administrative
Costs by Regulatory Option
Regulatory Scenario
Scenario 1
Scenario 2
Scenario 3
Scenario 4a
Scenario 4b
State
$3,922,990
$7,233,470 .
$7,279,560
$5,910,750
$8>645,520
Federal
$268,630
$413,060
$415,600
$351,090
$483,010
Total
$4,191,620
$7,646,530
$7,695,160
$6,224,040
$9 128 530
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9.5 Changes to NPDES Regulations
In addition to changing the threshold for determining which facilities are CAFOs, EPA is
proposing a number of other changes that address how the permitting authority determines
whether a facility is an AFO or a CAPO, which must apply for an NPDES permit. These changes
also simplify, clarify, and strengthen the NPDES regulation.
9.5.1 Definition of AFO as It Relates to Pastures and Rangeland
EPA proposes to clarify the regulatory language that defines the term "Animal Feeding
Operation," or "AFO," to remove ambiguity. (See proposed §122.23(a)(2).) The revised rule
language would clarify that animals are not considered to be "stabled or confined" when they are
in areas such as pastures or rangeland that sustain crops or forage during the entire time the
animals are present. AFOs are enterprises where animals are kept and raised hi confined
situations. AFOs concentrate animals, feed, manure and urine, dead animals,, and production
operations on a small land area. Feed is brought to the animals rather than the animals grazing or
otherwise seeking feed hi pastures, hi fields, or on rangeland. The current regulation (40 CFR
122.23(b)(l)) defines an AFO as a "lot or facility where animals have been, are, or will be stabled
or confined and fed or maintained for a total of 45 days or more in any 12 month period; and
•where crops, vegetation [,] forage growth, or post-harvest residues are not sustained over any
portion of the lot or facility in the normal growing season" [emphasis added].
The existing definition states that animals must be kept on the lot or facility for a minimum, of 45
days in a 12-month period. If .an animal is at a facility for any portion of a day, it is considered to
be at the facility for a full day. This definition does not mean that the same animals must remain
on the lot for 45 consecutive days or more; it means only that some animals are fed or maintained
on the lot or at the facility for 45 days out of any 12-month period. The 45 days do not have to be
consecutive, and the 12-month period does not have to correspond to the calendar year. For
example, June 1 to the following May 31 would constitute a 12-month period.
The definition has proven to be difficult to implement and has led to some confusion. Some
CAFO operators have asserted that they are not AFOs under this definition where incidental
growth occurs on small portions of the confinement area. In the case of certain wintering
operations, animals confined during winter months quickly denude the feedlot of growth that
grew during the summer months. The AFO definition includes those confinement areas that have
growth over only a small portion of the facility or that have growth during only a portion of the
time that the animals are present. The definition excludes pastures and rangeland that are largely
covered with vegetation that can assimilate the nutrients hi the manure. The intention is for
AFOs to include areas where animals are confined hi such a density that significant vegetation
cannot be sustained over most of the confinement area.
As indicated hi EPA's 1974-Development Document, the reference to vegetation hi the definition
is intended to distinguish feedlots (whether outdoor confinement areas or indoor covered areas
with constructed floors) from pasture or grazing land. If a facility maintains animals in an area
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without vegetation, including dirt lots or constructed floors, the facility meets this part of the
definition. EPA also considers dirt lots with nominal vegetative growth while animals are present
to meet the second part of the AFO definition, even if substantial growth of vegetation occurs
during months when animals are kept elsewhere. Thus, in the case of a wintering operation, EPA
considers the facility an AFO potentially subject to NPDES regulations as a CAFO. It is not
EPA's intention to include within the AFO definition pasture or rangeland that has a small, bare
patch of land, in an otherwise vegetated area, that is caused by animals frequently congregating if
the animals are not confined to the area.
The following examples are presented to further clarify EPA's intent. (1) When animals are
restricted to vegetated areas as in the case of rotational grazing, they would not be considered to
be confined in an AFO if they are rotated out of the area while the ground is still covered with
vegetation. (2) If a small portion of a pasture is barren because, for example, animals congregate
near the feed trough in that portion of the pasture, that area is not considered an AFO because
animals are not confined to the barren area. (3) If an area has vegetation when animals are
initially confined there, but the animals remove the vegetation during their confinement, that area
would be considered an AFO. This situation might occur, for instance, at some wintering
operations.
To address the ambiguities noted above, EPA is proposing regulatory language that defines the
term "animal feeding operation" as follows: "An animal feeding operation or AFO is a facility
where animals (other than aquatic animals) have been, are, or will be stabled or confined and fed
or maintained for a total of 45 days or more in any 12-month period. Animals are not considered
to be stabled or confined when they are in areas such as pastures or rangeland that sustain crops
or forage growth during the entire time that animals are present. Animal feeding operations
include both the production area and land application area as defined below."
9.5.2 Definition of AFO as It Relates to Land Application Areas
EPA revised the definition of an AFO to include both the animal production areas of the
operation and the land areas, if any, under the control of the owner or operator, on which manure
and associated wastewaters are applied. (See proposed §122.23(a)(2).) The definition of a
CAFO is based on the AFO definition and thus would include the land application areas as well.
Accordingly, a permit for a CAFO would include requirements to control not only discharges
from the production areas but also discharges from the land application areas. Under the existing
regulations, discharges from a CAFO's land application areas that result from improper
agricultural practices are already considered to be discharges from the CAFO and therefore are
subject to the NPDES permitting program. However, EPA believes it would be helpful to clarify
the regulations on this point.
By the term "production area" EPA means the animal confinement areas, the manure storage
areas (e.g., lagoon, shed, pile), the feed storage areas (e.g., silo, silage bunker), and the waste
containment areas (e.g., berms, diversions). The land application areas include any land to which
a CAFO's manure and wastewater is applied (e.g., crop fields, fields, pasture) that is under the
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control of the CAFO owner or operator whether through ownership or a lease or contract. The
land application areas do not include areas that are not under the CAFO owner's or operator's
control. For example, where a nearby farm is owned and operated by someone other than the
CAFO owner or operator, and the nearby farm applies manure from the CAFO to its own crop
fields, those crop fields are not part of the CAFO.
The definition of an AFO under the existing regulations refers to a "lot or facility" that meets
certain conditions, including that "[c]rops, vegetationf,] forage growth, or post-harvest residues
are not sustained in the normal growing season over any portion of the lot or facility" (40 CFR
122.23(b)(l)). In addition, the regulations define "discharge of a pollutant" as the addition of any
pollutant to waters of the United States from any point source (40 CFR 122.2). EPA interprets
the current regulations to include discharges of CAFO-generated manure and wastewaters from
land application areas under the control of the CAFO as discharges from the CAFO itself.
Otherwise, a CAFO could simply move its wastes outside the area of confinement and oyerapply
or otherwise improperly apply those wastes, which would render the CWA prohibition on
unpermitted discharges of pollutants from CAFOs meaningless. Moreover, the pipes and other
manure-spreading equipment that convey CAFO manure and wastewaters to land application
areas under the control of the CAFO are an integral part of the CAFO. Under the existing .
regulations, this equipment should be considered part of the CAFO, and discharges from this
equipment that reach the waters of the United States should be considered discharges from the
CAFO for this reason as well. In recent litigation brought by citizens against a dairy farm,, a
federal court reached a similar conclusion. See CARE v. SidKoopman Dairy, et al, 54 F. Supp.
2d 976 (E.D. Wash., 1999). .
Land application areas are integral parts of many or most CAFO operations. Land application is
typically the endpoint in the cycle of manure management at CAFOs. Significant discharges to
the nation's waters in the past have been attributed to the land application of CAFO-generated
manure and wastewater. EPA does not believe that Congress intended to exclude the discharges
from a CAFO's land application areas from coverage as discharges from the CAFO point source.
Moreover, defining CAFOs in this way is consistent with EPA's effluent limitations guidelines
for other industries, which consider on-site waste treatment systems to be part of the production
facilities in that the regulations restrict discharges from the total operation. Thus, it is reasonable
for EPA to clarify the regulations by including land application areas hi the definition of an AFO
and CAFO.
EPA believes that amending the definition of an AFO (and, by extension, CAFO) to expressly
include land application areas will help achieve clarity and will enable permitting authorities both
to more effectively implement the proposed effluent guidelines and to more effectively enforce
the CWA's prohibition on discharging without a permit. This revision clarifies that the term
"CAFO" means the entire facility, including land application fields and other areas under the
CAFO's control to which it land applies its manure and wastewater. By proposing to include
land application areas in the definition of an AFO (and therefore, a CAFO), discharges from those
areas would, by definition, be discharges from a point source, i.e., the CAFO. There would not
need to be a separate showing of a discernible, confined, and discrete conveyance such as a ditch.
9-46
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Although the proposal would clarify that land application areas are considered to be part of the
AFO and CAFO, it would continue to count only those animals that are confined in the
production area when determining whether a facility is a CAFO.
9.5.3 Elimination of the Term "Animal Units"
To remove confusion for the regulated community concerning the definition of the term "animal
unit" or "AU," EPA is proposing to eliminate the use of the term in the revised regulation.
Instead of referring to facilities as having greater or fewer than 500 animal units, for example,
EPA will use the term "CAFOs" to refer to those facilities that are defined or designated as such
and the term "AFOs" for all others. However, the term AU will be used in descriptive text to
help the reader understand the differences between the existing regulation and the revisions. If
this revision is adopted, the term AU will not be used hi the final regulation.
EPA received comment on the concept of animal units during the AFO Strategy listening sessions
and the small business outreach process, and in comments submitted for the draft CAFO NPDES
Permit Guidance and Example Permit. EPA's decision to move away from the concept of
animal units is supported by the inconsistent use of this concept across a number of federal
programs, which has resulted in confusion in the regulated community. A common thread across
all of the federal programs is the need to normalize numbers of animals across animal types.
Animal units have been established based on a number of different values that include live
weight, forage requirements, and nutrient excretion. Among others, USDA and EPA have
different "animal unit" values for the livestock sectors. Annual unit values most often used by
USDA are live-weight based and account for all sizes and breeds of animals likely to be at a
given operation. This is particularly confusing because USDA's animal unit descriptions result in
different values in each sector and at each operation.
The United States Department of the Interior (Bureau of Land Management and NationaLPark
Service) also references the concept of animal unit in a number of programs. These programs are
responsible for the collection of grazing fees for federal lands. The animal unit values used in
these programs are based upon forage requirements. For federal lands an animal unit represents
one mature cow, bull, steer, heifer, horse, or mule, or five sheep, or five goats, all over 6 months
of age. An animal unit month is based on the amount of forage needed to sustain one animal unit
for one month. Grazing fees for federal lands are charged by animal unit months.
Li summary, using the total number of head that defines an operation as a CAFO will minimize
confusion with animal unit definitions established by other programs.
9.5.4 Elimination of Multipliers for Mixed Animal Types
EPA proposes to eliminate the existing mixed animal provision,, which currently requires an
operator to add the number of animal units from all animal sectors at the facility when
determining whether it is a CAFO. Poultry, dairy calves, and swine under 55 pounds are
currently excluded from this mixed animal type calculation. Although the mixed calculation
9-47
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would be eliminated, once the number of animals from any one livestock sector causes an
operation to be defined as a CAFO, manure and animals from all confined animal types at the
facility would be covered by the permit. In the event waste streams from multiple livestock
species are commingled, the permit must apply the more stringent limitations as permit
conditions.
In the existing regulation, a facility is a CAFO when the cumulative number of animal units
exceeds 1,000. Animal unit means a unit of measurement for any animal feeding operation
calculated by adding the following numbers: the number of slaughter and feeder cattle multiplied
by 1.0, plus the number of mature dairy cattle multiplied by 1.4, plus the number of swine
weighing more than 25 kilograms (approximately 55 pounds) multiplied by 0.4, plus the number
of sheep multiplied by 0.1, plus the number of horses multiplied by 2.0. As mentioned, poultry
operations are excluded from this mixed unit calculation because the current regulation simply
stipulates the number of birds that define the operation as a CAFO and assigns no multiplier.
Because simplicity is one objective of these proposed regulatory revisions, the Agency believes
that either (1) all animal types covered by the effluent guidelines and NPDES regulation,
including poultry and immature animals, should be included in the formula for mixed facilities, or
(2) EPA should eliminate the animal multipliers from the revised rule. Note the revised rule also
changes those animal types and sizes that would have to be factored into a revised mixed animal
calculation, which could make the regulation more complicated.
EPA believes that the effect of this change would be sufficiently protective of the environment
while maintaining a consistently enforceable regulation. EPA estimates 25 percent of AFOs with
fewer than 1,000 AU have multiple animal types present simultaneously at one location, and only
a small fraction of these AFOs would be CAFOs larger than either 300 AU or 500 AU when all
animal types are counted. Census data suggest that few large AFOs house more than one animal
type due to the increasingly specialized nature of livestock and poultry production. Most
facilities with mixed animal types tend to be much smaller farms, tend to be less specialized, and
typically engage in both animal and crop production. These farms have sufficient cropland and
fertilizer requirements to land apply most, if not all, manure nutrients generated by the farm.
Therefore, EPA believes that a rule requiring mixed animal types to be part of the threshold
calculation to determine whether a facility is a CAFO would result in relatively few additional
operations meeting the definition of a CAFO. Nevertheless, should such an AFO be found to be
a significant contributor of pollution to waters of the United States, it could still be designated a
CAFO by the permit authority.
EPA, therefore, proposes to eliminate the mixed animal calculation in determining which AFOs
are CAFOs. Once an operation is a CAFO for any reason, manure from all confined animal types
at the facility is subject to 'the permit requirements.
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9.5.5 Elimination of 25/24 Storm Permit Exemption
The existing NPDES definition of a CAFO provides that "no animal feeding operation is a
concentrated animal feeding operation... as defined above... if such animal feeding operation
discharges only as the result of a 25-year, 24-hour storm event" (40 CFR 122.23, Appendix B).
This provision applies to AFOs with 300 AU or more that are defined as CAFOs under the
existing regulation. Facilities of any size that are CAFOs by virtue of designation are not eligible
for this exemption because, by the terms of designation, the exemption does not apply to them.
Moreover, they have been determined by the permit authority to be a significant contributor of
pollution to waters of the United States. EPA proposes to eliminate the 25-year, 24-hour storm
event exemption from the CAFO definition (40 CFR 122.23, Appendix B) and to require any
operation that meets the definition of a CAFO either to apply for a permit or to establish that it
has no potential to discharge.
The 25-year, 24-hour standard is an engineering standard used for construction of storm water
detention structures. The term "25-year, 24-hour storm event" means the maximum 24-hour
precipitation event with a probable recurrence of once in 25 years, as defined by the National
Weather Service (NWS) in Technical Paper Number 40 (TP40), "Rainfall Frequency Atlas of the
United States," May 1961, and subsequent amendments, or by equivalent regional or state rainfall
probability information developed therefrom. As discussed in Chapter 8, the 25-year, 24-hour
storm event is used as a design standard hi the effluent limitation guideline.
The circularity of the 25-year, 24-hour storm event exemption in the existing CAFO definition
has created confusion and has led to difficulties in implementing the NPDES regulation. .The
effluent guidelines regulation, which is applicable to permitted CAFOs, requires that CAFOs be
designed and constructed to contain such an event. However, the NPDES regulations allow
facilities that discharge only as a result of such an event to avoid obtaining a permit. This
exemption has resulted hi very few operations actually obtaining NPDES permits, which has
hampered implementation of the NPDES program. Although an estimated 12,000 AFOs are
likely to meet the current definition of a CAFO, only about 2,500 such facilities have obtained an
NPDES permit. Many of these unpermitted facilities may incorrectly believe they qualify for the
25-year, 24-hour storm permitting exemption; these unpermitted facilities operate outside the
current NPDES program. Consequently, state and EPA NPDES permit authorities lack the basic
information needed to determine whether the exemption has been applied correctly and whether
the CAFO operation is hi compliance with NPDES program requirements.
EPA proposes to eliminate the 25-year, 24-hour storm exemption from the CAFO definition to
(1) ensure that all CAFOs with a potential to discharge are appropriately permitted; (2) ensure
through permitting that facilities are, in fact, properly designed, constructed, and maintained to
contain a 25-year, 24-hour storm event, or to meet a zero discharge requirement, as the case may
be; (3) improve the ability of EPA and state permit authorities to monitor compliance; (4) ensure
that facilities do not discharge pollutants from then: production areas or from excessive land
application of manure and wastewater; (5) make the NPDES permitting provision consistent with
the proposal to eliminate the 25-year, 24-hour storm design standard from the effluent guidelines
9-49
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for swine, veal, and poultry; and (6) achieve EPA's goals of simplifying the regulation, providing
clarity to the regulated community, and improving the consistency of implementation.
EPA considered limiting this change to the very largest CAFOs (e.g., operations with 1,000 or
more animal units) and retaining the exemption for smaller facilities. However, EPA is
concerned that this approach would allow significant discharges resulting from nonagricultural
land application of manure and wastewater to remain beyond the scope of the NPDES permitting •
program, thereby resulting in ongoing discharge of CAFO-generated pollutants into waters of the
United States. EPA is also concerned about reports of small facilities in aggregate contributing
large quantities of pollutants to waters of the United States. Moreover, EPA believes that
retaining the exemption for certain operations adds unnecessary complexity to the CAFO
definition.
9.5.6 No Potential to Discharge/Duty to Apply
EPA is proposing to adopt regulations that would expressly require all CAFO owners or operators
to apply for an NPDES permit. That is, owners or operators of all facilities defined or designated
as CAFOs would be required to apply for an NPDES permit. The existing regulations contain a
general duty to apply for a permit, which EPA believes applies to virtually all CAFOs. The
majority of CAFO owners or operators, however, have not applied for an NPDES permit. The
proposed revisions would clarify that all-CAFO owners or operators must apply for an NPDES
permit; however, if the owner or operator believes the CAFO does not have a potential to
discharge pollutants to waters of the United States from either its production area or its land
application area(s), he or she could make a no,potential discharge demonstration to the permit
authority in lieu of submitting a full permit application. If the permit authority agrees that the
CAFO does not have a potential to discharge, the permit authority would not need to issue a
permit However, if the unpermitted CAFO does indeed discharge, it would be violating the
CWA prohibition against discharging without a permit and would be subject to civil and criminal
penalties. Thus, an unpermitted CAFO does not receive the benefit of the 25-year, 24-hour storm
standard established by the effluent guidelines for beef and dairy, nor does it have the benefit of
the upset and bypass affirmative defenses.
EPA believes that virtually all facilities defined as CAFOs already have a duty to apply for a
permit under the current NPDES regulations because of their past or current discharges or
potential for future discharge. Large CAFOs pose a risk of discharge in a number of different
ways. For example, a discharge of pollutants to surface waters can occur through a spill from the
waste handling facilities, from a breach or overflow of those facilities, or through runoff from the
feedlot area. A discharge can also occur through runoff of pollutants from application of manure
and associated wastewaters to cropland, or through seepage from the production area to ground
water where there is a direct hydrologic connection between ground water and surface water.
Given the large volume of manure these facilities generate and the variety of ways they may
discharge, and based on EPA's and the states' own experience in the field, EPA believes mat all
or virtually all large CAFOs have had a discharge in the past, have a current discharge, or have
the potential to discharge hi the future. A CAFO that meets any one of these three criteria would
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be a facility that "discharges or proposes to discharge" pollutants and would, therefore, need to
apply for a permit under the current regulations.
Where a CAFO has not discharged pollutants in the past, does not now discharge pollutants, and
does not expect to discharge pollutants in the future, EPA believes that the owner or operator of
that facility should demonstrate during the NPDES permit application process that it is, in fact, a
"no discharge" facility. EPA anticipates that very few large CAFOs will be able to successfully
demonstrate that they do not discharge pollutants and do not have a reasonable potential to
discharge hi the future. Furthermore, very few large CAFOs will wish to forego the protections
of an NPDES permit. For instance, only those beef and dairy CAFOs with an NPDES permit will
be authorized to discharge in a 25-year, 24-hour storm.
The nature of these operations is that any discharges from manure storage structures to waters of
the United States are usually only intermittent, due to either accidental releases from equipment
failures or storm events or, in some cases, deliberate releases such as pumping out lagoons or pits.
The intermittent nature of these discharges, combined with the large numbers of animal feeding
operations nationwide, makes it very difficult for EPA and state regulatory agencies to know
where discharges have occurred (or, in many cases, where AFOs are even located), given the
limited resources for conducting inspections. In this sense, CAFOs are distinct from typical
industrial point sources subject to the NPDES program, such as manufacturing plants, where a
facility's existence and location and the fact that it is discharging wastewaters at all are usually
not in question. Accordingly, it is much easier for CAFOs to avoid the permitting system by not
reporting their discharges, and there is evidence that such avoidances have taken place.
EPA believes that virtually all large CAFOs have had a past discharge or have a current discharge
or have the potential to discharge in the future, and that meeting any one of these criteria would
trigger a duty to apply for a permit. EPA proposes to revise the regulations by finding that, as a
rebuttable presumption, all CAFOs do have a potential to discharge and, therefore, are required to
apply for and to obtain an NPDES permit unless they can demonstrate that they will not
discharge. EPA has not previously sought to categorically adopt a duty to apply for an NPDES
permit for all facilities within a particular industrial sector. EPA proposes to do so for CAFOs for
reasons that involve the unique characteristics of CAFOs and the zero discharge regulatory
approach that applies to them.
9.5.7 Applicability to All Poultry
The existing NPDES CAFO definition is written such that the regulations apply only to laying
hen or broiler operations that have continuous overflow watering or liquid manure handling
systems (i.e.,"wet" systems) (40 CFR 22.23, Appendix B). EPA has interpreted this language to
include poultry operations in which dry litter is removed from pens and stacked in areas exposed
to rainfall or in piles adjacent to a watercourse. These operations may be considered to have
established a crude liquid manure system (see 1995 NPDES Permitting Guidance for CAFOs).
The existing CAFO regulations also specify different thresholds for determining which AFOs are
CAFOs depending on which of these two types of systems the facility uses (e.g., 100,000 laying .
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hens or broilers if the facility has continuous overflow watering; 30,000 laying hens or boilers if
the facility has a liquid manure system). When the NPDES CAFO regulations were promulgated,
EPA selected these thresholds because the Agency believed that most commercial operations
used wet systems (38 FR 18001,1973). Note that turkeys were regulated at 55,000 birds (1,000
AU) irrespective of manure handling system.
In the 25 years since the CAFO regulations were promulgated, the poultry industry has changed
many of its production practices. Many changes to the layer production process have been
instituted to keep manure as dry as possible, such as high-rise houses or houses with belts under
the cages. The broiler industry uses litter-based systems almost exclusively. Consequently, the
existing regulations do not apply to most broiler and laying hen operations despite the fact that
chicken production poses risks to surface water and ground water quality from improper storage
of dry manure and improper land application. It is EPA's understanding that continuous overflow
watering has been largely discontinued, and has been replaced with more efficient watering
methods (on-demand watering), and that liquid manure handling systems represent few layer
operations overall, although in the South approximately half of the layer operations might still
have wet manure systems (see Chapter 4).
Despite the CAFO regulations, nutrients from large poultry operations continue to contaminate
surface water and ground water because of rainfall coming into contact with outdoor manure
stacks, accidental spills, faulty watering lines, open lagoons for egg wash water, and so forth.
Poultry production concentrated in areas such as the Southeast, the Delmarva Peninsula in the
Mid Atlantic, and key midwestern states has been shown to cause serious water quality
impairments (see Environmental Impact Assessment document). In addition, land application
remains the primary management method for significant quantities of poultry litter (including
manure generated from facilities using "dry" systems). Many poultry operations are located on
smaller parcels of land in comparison to other livestock sectors, oftentimes owning no significant
cropland or pasture, placing increased importance on the proper management of the potentially
large amounts of manure they generate. EPA also believes that all major livestock operations
should be treated equitably under the revised regulation.
The existing regulation already applies to laying hen and broiler operations with 100,000 birds
when a continuous flow watering system is used, and to operations with 30,000 birds when a
liquid manure handling system is used. In revising the threshold for poultry operations, EPA
evaluated several additional methods for equating poultry to the existing definition of an animal
unit EPA considered laying hens, pullets, broilers, and roasters separately to reflect the
differences in size, age, production, feeding practices, housing, waste management, manure
generation, and nutrient content of the manure. Manure generation and pollutant parameters
considered include nitrogen, phosphorus, BODS, volatile solids, and COD. Analysis of these
parameters consistently results in a threshold of 70,000 to 140,000 birds as being equivalent to
1,000 animal units. EPA also considered a live-weight basis for defining poultry. The live-weight
definition of animal unit used by USDA defines 455,000 broilers and pullets and 250,000 layers
as being representative of 1,000 animal units. EPA data indicate that using a live-weight basis at
1,000 AU would exclude virtually all broiler operations from the regulation.
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Consultations with industry indicated EPA should evaluate the different sizes (ages) and purposes
(eggs versus meat) of chickens separately. However, when evaluating broilers, roasters, and other
meat-type chickens, EPA concluded that a given number of birds capacity represented the same
net annual production of litter and nutrients. For example, a farm producing primarily broilers
would raise birds for 6 to 8 weeks with a final weight of 3 to 5 pounds, and a farm producing
roasters would raise birds for 9 to 11 weeks with a final weight of 6 to 8 pounds, whereas a farm
producing game hens might keep birds for only 4 to 6 weeks with a final weight of less than 2
pounds. The housing, production practices, waste management, and manure nutrients and
process wastes generated in each case, however, are essentially the same. Layers are typically fed
less than broilers of equivalent size and are generally maintained as smaller chickens. However,
a laying hen is likely to be kept for a year of egg production. The layer is then sold or molted for
several weeks, followed by a second period of egg production. Pullets are housed until a laying
age of approximately 18 to 22 weeks. In all cases manure nutrients and litter generated result in a
threshold of 80,000 to 130,000 birds as being the equivalent of 1,000 animal units. (See Chapters
4 and 6 for more information.)
The proposed NPDES (and effluent guidelines) requirements for poultry eliminate the distinction
between how manure is handled and the type of watering system used. EPA is proposing this
change because it believes there is a need to control poultry operations regardless of the manure
•handling or watering system. EPA believes that improper storage, as well as land application
rates that exceed agricultural use, has contributed to water quality problems, especially in areas
with large concentrations of poultry production. Inclusion of poultry operations in the proposed
NPDES regulation is intended to be consistent with the proposed effluent guidelines regulation.
EPA is proposing that 100,000 laying hens or broilers be considered the equivalent of 1,000
animal units.
Consequently, EPA proposes to establish 50,000 birds as the threshold under the two-tier
alternative structure (Scenario 4) that defines which operations are CAFOs at 500 animal units.
Facilities subject to designation are those with fewer than 50,000 birds. This threshold would
address approximately 10 percent of all chicken AFOs nationally and more than 70 percent of all
manure generated by chickens. On a sector-specific basis, this threshold would address
approximately 28 percent of all broiler operations (including all meat-type chickens) while
addressing more than 70 percent of manure generated by broiler operations. For layers (including
pullets) the threshold would address less than 5 percent of layer operations while addressing
nearly 80 percent of manure generated by layer operations. EPA believes this threshold is
consistent with the threshold established for the other livestock sectors.
Under the proposed alternative three-tier structures (Scenarios 1,2, and 3), any operation with
more than 100,000 chickens is automatically denned as a CAFO. This upper tier reflects 4
percent of all chicken operations. Additionally, those poultry operations with 30,000 to 100,000
chickens are defined as CAFOs if they meet certain unacceptable conditions (see section 9.2).
This middle tier would address an additional 10 percent of poultry facilities. By sector this
middle tier would potentially cover an additional 45 percent of broiler manure and 22 percent of
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layer manure. In aggregate this scenario would address 14 percent of chicken operations and 86
percent of manure.
The revision would remove the limitation on the type of manure handling or watering system
employed at laying hen and broiler operations and would, therefore, address all poultry operations
equally. This approach would be consistent with EPA's objective of better addressing the issue
of water quality impacts associated with both storage of manure at the production area and land
application of manure while simultaneously simplifying the regulation.
EPA acknowledges that this poultry threshold pulls in a substantial number of broiler operations
in select regions. However, a higher threshold would include very few poultry facilities in other
select regions. Geographic regions with high density of poultry production have experienced
water quality problems related to an overabundance of nutrients, to which the poultry industry has
contributed. The chicken and turkey sectors also have higher percentages of operations with
insufficient or no land under the control of the AFO on which to apply manure. Thus EPA
believes this threshold is appropriate to adequately control the potential for discharges from
poultry CAFOs.
9.5.8 Applicability to Immature Animals
Only swine over 55 pounds and mature dairy cows are specifically included in the current
definition (although manure and wastewater generated by immature animals confined at the same
operation with mature animals are subject to the existing requirements). Immature animals were
not a concern in the past because they were generally part of operations that included mature
animals and, therefore, their manure was included in the permit requirements of the CAFO. In
recent years, however, these livestock industries have become increasingly specialized with the
emergence of increasing numbers of large stand-alone facilities such as nurseries and contract
heifer operations. Further, manure from immature animals tends to have higher concentrations of
pathogens and hormones and thus poses greater risks to the environment and human health.
Since the 1970s the animal feeding industry has become more specialized, especially at larger
operations. Dairies often move immature heifers to a separate location until they reach maturity.
These off-site operations may confine the heifers in a manner that is very similar to a beef feedlot,
or the heifers may be placed on pasture. The existing CAFO definition does not address
operations that confine only immature heifers. EPA acknowledges that dairies may keep heifers
and calves and a few bulls on site. EPA data indicate some of these animals are in confinement,
some are pastured, and some are moved back and forth between confinement, open lots, and
pasture. However; the actual milking herd tends to be a more constant number of animals that
are confined at least during milking. The current CAFO definition thus considers only the mature
milking cows. This has raised some concerns that many dairies with significant numbers of
immature animals could be excluded from the regulatory definition even though they might
generate as much manure as a dairy with a milking herd large enough to make the dairy a CAFO.
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EPA considered options for dairies that would take into account all animals maintained in
confinement, including calves, bulls, and heifers, when determining whether a dairy is a CAFO.
EPA examined two approaches for this option—one that would count all animals equally and
another based on the proportion of heifers, calves, and bulls likely to be present at the dairy. The
milking herd is usually a constant at a dairy, but the proportion of immature animals can vary
substantially among dairies and even at a given dairy over time. Some operations maintain their
immature animals on-site but keep them on pasture most of the time. Some operations keep
immature animals on-site and maintain them in confinement all or most of the time. Some
operations may also have one or two bulls on-site,, which can also be kept either in confinement
or on pasture, while many keep none on-site. Some operations do not keep their immature
animals on-site at all; instead, they place them off-site, usually in a stand-alone heifer operation.
The variety of practices at dairies makes it very difficult to estimate how many operations have
immature animals on-site in confinement. EPA believes that basing the applicability on the
numbers of immature animals and bulls would make implementing the regulation more difficult
for the permit authority and the CAFO operator.
When the CAFO regulations were issued, it was typical to house swine from birth to slaughter
together at the same operation, known as a farrow-to-finish operation. Although more than half
of swine production continues to occur at farrow-to-fimslLoperations,today it is common for
swine to be raised in phased production systems. Though EPA could not identify any large stand-
alone nursery facilities in 1997, other data indicate the emergence of several large nursery
operations. EPA proposes to count either swine over 55 pounds or swine under 55 pounds to
determine the size of the AFO and the applicability of the NPDES and effluent limitations
guidelines (ELG) regulations.
The proposed thresholds for swine were established on the basis of the average phosphorus
excreted from immature swine in comparison to the average phosphorus excreted from swine
over 55 pounds. A similar threshold would be obtained when evaluating live-weight manure
generation, nitrogen, COD, and volatile solids (VS). See Chapter 6 for more information on
manure constituents. The thresholds for heifers are based on the thresholds for beef cattle.
EPA's data on contract heifer operations indicate the heifers are often.maintained on feedlots hi a
manner identical to the manner in which beef cattle are raised; additionally, some beef feedlots
have been known to temporarily maintain heifers on-site.
Thus, EPA proposes to include immature swine and heifer operations under the CAFO definition.
In the proposed three-tier structure, the 300 AU and 1,000 AU equivalents, respectively, for each
animal type would be 3,000 head and 10,000 head for immature swine and 300 head and 1,000
head for heifers. In the proposed two-tier structure, EPA would establish the 500 AU threshold
equivalent for defining which operations are CAFOs as operations with 5,000 or more swine
weighing 55 pounds or less; those with fewer than 5,000 swine under 55 pounds are AFOs that
may be designated CAFOs. Immature dairy cows, or heifers, would be counted equivalent to beef
cattle; that is, the 500 AU threshold equivalent for defining CAFOs would be operations with 500
or more heifers, and those with fewer than 500 heifers could be designated CAFOs.
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9.5.9 NPDES Thresholds for Animal Types Not Covered by the ELG
The animal types covered by the NPDES program are defined in the current regulation (40 CFR
Part 122, Appendix B). The beef, dairy, swine, poultry, and veal sectors are being addressed by
both revisions to the ELG and NPDES regulations. However, EPA is not revising the ELG for
any animal sector other than beef (including veal), dairy, swine, and poultry. Therefore, any
CAFO in the horse, sheep, lamb and duck sectors with fewer than 1,000 AU will not be subject to
the ELG, but will have NPDES permits developed on a best professional judgment basis. EPA is
proposing to lower the threshold for defining which AFOs are CAFOs for these sectors if the
two-tier structure is adopted. This action is being taken to be consistent with the NPDES
proposed revisions for beef, dairy, swine, and poultry. Under the three-tier structures, the existing
thresholds would remain as they are under the existing'regulation. A facility confining any other
animal type that is not explicitly mentioned in the NPDES and ELG regulations is still subject to
NPDES permitting requirements if it meets the definition of an AFO and if the permit authority
designates it a CAFO on the basis that it is a significant contributor of pollution to waters of the
United States.
The economic analysis for the NPDES rule does not cover animal types other than beef, dairy,
swine, and poultry. EPA chose to analyze those animal types that produce the greatest amount of
manure and wastewater in the aggregate while in confinement. EPA believes that most horse,
sheep, and lamb operations are not confined and, therefore, will not be subject to permitting.
Thus the Agency expects the impacts in these sectors to be minimal.
9.5.10 Duty to Maintain Permit Coverage Until Closure
EPA proposes to require operators of permitted CAFOs that cease operations to retain NPDES
permits until the facilities are properly closed, i.e., no longer have the potential to discharge.
Similarly, if a facility ceases to be an active CAFO (e.g., it decreases the number of animals to
below the threshold that defined it as a CAFO, or ceases to operate), the CAFO must remain
permitted until all wastes at the facility that were generated while the facility was a CAFO no
longer have the potential to reach waters of the United States. If a permit is about to expire and
the manure storage facility has not yet been properly closed, the facility would be required to
apply for a permit renewal because the facility has the potential to discharge to waters of the
United States until it is properly closed. Proper facility closure includes removal of wastes from
lagoons and stockpiles, proper land application-of manure and wastewater, and proper disposal of
other wastes in accordance with NPDES permit requirements.
The existing regulations do not explicitly address whether a permit should be allowed to expire
when an owner or operator ceases operations. However, the public has expressed concerns about
facilities that go out of business, leaving lagoons, stockpiles, and other contaminants unattended
and unmanaged. Moreover, there are a number of documented instances of spills and breaches at
CAFOs that have ceased operations, leaving behind environmental problems that became a public
burden to resolve (NGDENR, 1999).
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EPA considered five options for NPDES permit requirements to ensure that CAFO operators
provide assurances for proper closure of their facilities (especially manure management systems
such as lagoons) in the event of financial failure or other business curtailment. EPA examined
the costs to the industry and the complexity of administering such a program for all options.
Closure Option 1 would require a closure plan. The CAFO operator would be required to have a
written closure plan detailing how the facility plans to dispose of animal waste from manure
management facilities. The plan would be submitted with the permit application and be approved
with the permit application. The plan would identify the steps necessary to perform final closure
of the facility, including at least the following:
A description of how each major component of the manure management facility(e.g.,
lagoons, settlement basins, storage sheds) will be closed.
An estimate of the maximum inventory of animal waste ever on-site, accompanied with a
description of how the waste will be removed, transported, land applied or otherwise
disposed.
A closure schedule for each component of the facility, along with a description of other
activities necessary during closure (e.g., control runoff/run-on, ground water monitoring if
necessary).
EPA also investigated several options that would provide financial assurances in the event the
CAFO went out of business, such as contribution to a sinking fund, commercial insurance, surety
bond, and other common commercial mechanisms. Under Closure Option 2, permittees would
have to contribute to a sinking fund to cover .closure, costs of facilities that abandon, their manure
management systems. The contribution could be on a per-head basis and could be levied on the
permitting cycle (every 5 years) or annually. The sinking fund would be available to clean up any
abandoned facility (including those which are not permitted). Data on lagoon closures in North
Carolina (NCDENR, 1999) indicate that the average cost of lagoon closure for which data are
available is approximately $42,000. Assuming a levy of $0.10 per animal, the sinking fund
would cover the cost of approximately 50 abandonments nationally per year, not accounting for
any administrative costs associated with operating the funding program.
Closure Option 3 would require permittees to provide financial assurance by one of several
generally accepted mechanisms, including the following: (1) commercial insurance, (2) financial
test, (3) guarantee, (4) certificate of deposit or designated savings account, (5) letter of credit, or
(6) surety bond. The actual cost to the permittee would depend on which financial assurance
option was available and implemented. The financial test would likely be the least expensive for
some operations, entailing documentation that the net worth of the CAFO operator is sufficient to
make it unlikely that the facility will be abandoned for financial reasons. The guarantee would
also be inexpensive, consisting of a legal guarantee from a parent corporation or other party
(integrator) that has sufficient levels of net worth. The surety bond would likely be the most
expensive, typically requiring an annual premium of 0.5 to 3.0 percent of the value of the bond;
this mechanism would likely be a last resort for facilities that could not meet the requirement of
the other mechanisms.
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Option 4 is a combination of Options 2 and 3. Permittees would have, to provide financial.
assurance by using one of several generally accepted mechanisms or by participating in a sinking
fund. CAFO operators could meet closure requirements through the most economical means
available for their operations.
Option 5 simply requires CAFOs to maintain NPDES permit coverage until proper closure.
Under this option, facilities would be required to maintain their NPDES permits, even upon
curtailment of the operation, for as long as the facility has the potential to discharge. The costs
for this option would be those costs associated with maintaining a permit.
EPA selected Option 5: to require NPDES permits to include a condition that imposes a duty to
reapply for a permit unless an owner or operator has closed the facility such that there is no .
potential for discharges. The NPDES program offers legal and financial sanctions that are
sufficient, in EPA's view, to ensure that operators comply with this requirement. EPA believes
that this option would accomplish its objectives and would be generally easy and effective to
implement However, there are concerns that it would not be effective for abandoned facilities
because, unlike some of the other options, no financial assurance mechanism would be in place.
9.5.11 Assessment of Direct Hydrological Connection to Surface Water as Permit Condition
Because of its relevance to today's proposal, EPA is restating that the Agency interprets the Clean
Water Act to apply to discharges of pollutants from a point source via ground water that has a
direct hydrologic connection to surface water. Specifically, the Agency is proposing that all
CAFOs, including those that discharge or that have the potential to discharge CAFO wastes to
navigable waters via ground water with a direct hydrologic connection, must apply for an NPDES
permit. In addition, the proposed effluent guidelines will require some CAFOs to achieve zero
discharge from their production areas, including via ground water that has a direct hydrologic
connection to surface water. Further, for CAFOs not subject to such an effluent guideline, permit
writers would in some circumstances be required to establish special conditions to address such
discharges. In all cases, a permittee would have the opportunity to provide a hydrologist's report
to rebut the presumption that there is likely to be a discharge from the production area to surface
waters via ground water with a direct hydrologic connection.
For subcategories that would be subject to an effluent guideline that includes requirements for
zero discharge from the production area to surface water via ground water, the proposed
regulations would presume that there is a direct hydrologic connection to surface water. The
permittee would be required to either achieve zero discharge from the production area via ground
water and perform the required ground water monitoring, or provide a hydrologist's statement
that there is no direct connection of ground water to surface water at the facility.
Other subcategories are'subject to an effluent guideline that does not include ground water
requirements. In these cases -the permit writer first determines whether the facility is in an area
with topographical characteristics that indicate the presence of ground water that is likely to have
a direct hydrologic connection to surface water. If the permit writer determines that pollutants
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may be discharged at a level that might cause or contribute to an excursion above any State water
quality standard, the permit writer would be required to include special conditions to address
potential discharges via ground water. EPA proposes that the permittee must either comply with
those conditions or provide a hydrologist's statement that the facility does not have a direct
hydrologic connection to surface water.
If an ELG does not apply to the particular CAFO subcategory, the permit writer would be
required to decide on a case-by-case basis whether effluent limitations (technology-based and
water quality-based, as necessary) should be established to address potential discharges to surface
water via hydrologically connected ground water. Again, the permittee could avoid or satisfy
such requirements by providing a hydrologist's statement that there is no direct hydrologic
connection.
9.6 Land Application of Manure
EPA proposes to improve control of discharges that occur from land-applied manure and - -
wastewater. Analysis conducted by USDA indicates that, in some regions, the amount of
nutrients present in land-applied manure has the potential to exceed the nutrient needs of the
crops grown in those regions. Actual soil sample information compiled by researchers at various
land grant universities provides an indication of areas where there is widespread phosphorus
saturation. Other research by USDA documents the runoff potential of land-applied manure
under normal and peak precipitation. Furthermore, research from a variety of sources indicates
that there is a high correlation between areas with impaired lakes, streams, and rivers due to
nutrientenrichment and areas where there is dense livestock and-poultry.production.. ,,,. .
For CAFOs that land apply their manure, EPA is proposing that owners or operators implement
specific agricultural practices, including land application of manure and wastewater at a specified
rate, development and implementation of a Permit Nutrient Plan, a prohibition on the application
of CAFO manure or wastewater within 100 feet of surface water, and, as determined to be
necessary by the permit authority, restrictions on application of manure to frozen, snow-covered,
or saturated ground. The Agency is proposing to require these specific agricultural practices
under its GWA authority both to define the scope of the agricultural storm water discharge
exemption and to establish the best available technology for specific industrial sectors. Given the
history of improper disposal of CAFO waste and Congress's identification of CAFOs as point
sources, the Agency believes it should clearly define the agricultural practices that must be
implemented at CAFOs.
The Agency is proposing to allow AFO owners or operators who land apply manure obtained
from CAFOs and more traditional row crop farmers who land apply manure obtained from
CAFOs to qualify for the agricultural storm water exemption as long as they are applying manure
and wastewater at proper rates established by the state. Under the proposal, EPA is co-proposing
whether to require CAFOs that transfer manure to off-site recipients obtain a letter of certification
from the recipient land applier that the recipient intends to determine the nutrient needs of its
crops.based on realistic crop yields for its area, sample its soil at least once every 3 years to
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determine existing nutrient content, and not apply the manure in quantities that exceed the land
application rates calculated using the Phosphorus Index, Phosphorus Threshold, or Soil Test
Phosphorus method as specified in the revised ELG. For purposes of the CAFO's permit,
recipient land appliers need not implement all of the proper agricultural practices identified above
that CAFOs would be required to implement at their own land application areas. EPA believes
that this proposal enables the Agency to implement Congress's intent to both exclude truly
agricultural discharges due to storm water and regulate the disposition of the vast quantities of
manure and wastewater generated by CAFOs.
9.6.2 Other Special Permit Conditions
Permit writers establish effluent limits for land application areas in the form of rates and practices
that constitute proper agricultural practices to the extent necessary to fulfill the requirements of
the effluent guidelines or based on best professional judgment as well as to the extent necessary
to ensure that a CAFO's practices are agricultural in that they minimize the operation's impact on
water quality. Standard conditions in an NPDES permit list preestablished conditions that apply
to all NPDES permits. The special conditions in an NPDES permit are used primarily to
supplement effluent limitations and ensure compliance with the CWA.
In addition to closure, ground water, and off-site certification, EPA is proposing to require permit
authorities to develop special conditions that specify:
• How the permittee is to calculate the allowable manure application rate.
.».. Timing.restrictions, if necessary, on land application of manure and wastewater, including
restrictions on application to frozen, snow-covered, or saturated ground.
The ELG specifies three methods for determining the basis of manure application rates: (1) the
Phosphorus Index, (2) the Soil Phosphorus Threshold Level, and (3) the Soil Test Phosphorus
Level. EPA adopted these three methods from the USDA Natural Resource Conservation
Service's nutrient management standard (Standard 590, USDA NRCS, 2000). State Departments
of Agriculture are developing state nutrient standards that incorporate one of these three methods.
EPA is proposing to require that each authorized state permit authority adopt one of these three
methods as part of the state NPDES program, in consultation with the State Conservationist.
EPA considered establishing a national prohibition on applying CAFO-generated manure to
frozen, snow-covered or saturated ground in the ELG (Technology Option 7). Disposal of
manure or wastewater to frozen, snow-covered, or saturated ground is generally not a beneficial
use for agricultural purposes. Although such conditions can occur anywhere in the United States,
pollutant runoff associated with such practices is a site-specific consideration and is dependent on
a number of variables, including climate and topographic variability, distance to surface water,
and slope of the land. Such variability makes it difficult to develop a national technology-based
standard that is consistently reasonable and does not impose unnecessary cost on CAFO
operators.
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Although EPA believes that many permit writers will find a prohibition on applying CAFO-
generated manure to frozen, snow-covered, or saturated ground to be reasonably necessary to
achieve the effluent limitations and to carry out the purposes and intent of the CWA, EPA is
aware that there are areas where these practices might be allowed provided they are restricted.
Application on frozen ground, for example, might be appropriate in some areas provided there are
restrictions on the slope of the ground and proximity to surface water. Many states have already
developed such restrictions. The permit writer could further develop the restrictions based on a
consideration of local crop needs, climate, soil types, slope, and other factors.
Although the proposed regulations would not establish a national technology-based limitation or
BMP, EPA is proposing at section 122.23(j)(2) that permit writers consider the heed for these
limits. Permit authorities would be expected to develop restrictions on timing and method of
application that reflect regional considerations, which restrict applications that are not an
appropriate agricultural practice and have the potential to result in pollutant discharges to waters
of the United States. It is likely that the operators would need to consider means of ensuring
adequate storage to hold manure and wastewater for the period during which manure may not be
applied. EPA estimates that storage periods might range from 45 to 270 days, depending on the
region and the proximity to surface water, and to ground water with a direct hydrologic
connection to surface water. Permit authorities are .expected to work with state agricultural
departments, USDA's Natural Resource Conservation Service, the EPA regional office, and other
local interests to determine the appropriate standard, and include the standard consistently in all
NPDES permits for CAFOs.
EPA's, estimate that storage periods would range from 45 days to 270 days is derived using
published freeze/frost data from the National Oceanic and Atmospheric Administration, National
Center for Disease Control. For the purpose of estimating storage requirements to prevent
application to frozen ground, EPA assumed CAFOs could apply manure only between the last
spring frost and the first fall frost, called the "freeze free period." With a 90 percent probability,
EPA could also use a 28 degree temperature threshold to determine the storage time required,
rounded to the nearest 45-day increment. This calculation results in 45 days of storage in the'
South, 225 days in parts of the Midwest and the Mid-Atlantic, and as high as 270 days storage in
the Central region.
EPA believes the costs for this provision are minimal because the ELG already restricts manure
application to a rate that can be assimilated by the crops and soil. Where whiter spreading results
in runoff of the manure nutrients, the CAFO could not apply additional nutrients to compensate.
In other words, the PNP creates an incentive to apply nutrients only in a manner where they are
available to crops.
9.6.3 Non-CAFO Land Application Activities
In some instances, CAFO owners or operators transport their manure and/or wastewater off-site.
If off-site recipients land apply the CAFO-generated manure, they may be subject to regulation
under the Clean Water Act. In addition, AFOs may land apply their own manure and wastewater,
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and they, too, may be subject to regulation under !the Clean Water Act. A land applier could be
subject to regulation if (1) its field has a point source, as defined under the CWA, through which
(2) a discharge occurs that is not eligible for the agricultural storm water exemption, and (3) the
land applier is designated on a case-by-case basis as a regulated point source of storm water (40
CFR 122.26(a)(l)(v)). EPA notes that under the three-tier structure, an AFO with between 300
AU and 1,000 AU that has submitted a certification that it does not meet any of the conditions for
being a CAFO and, therefore, does not receive an NPDES permit, would be immediately subject
to enforcement and regulation under the Clean Water Act if it has a discharge that is not subject
to the agricultural storm water discharge exemption; EPA and the state do not need to designate
such a facility either a CAFO or a regulated storm water point source.
EPA emphasizes again that this regulatory approach is relevant only to discharges composed
entirely of storm water. If it is not due to precipitation, a discharge of manure or wastewater
through a point source, such as a ditch, into the waters of the United States need not be
designated subject to enforcement and regulation under the Clean Water Act.
As noted above, case-by-case designation of point sources at land application areas that are not
under the control of a CAFO owner or operator may already occur under existing regulations.
Either the permitting authority or EPA may designate a discharge that he or she determines
contributes to a violation of a water quality standard or is a significant contributor of pollutants to
waters of the United States. EPA is soliciting comment on whether to clarify the term "significant
contributor of pollutants" for the purposes of designating a discharge of manure and/or
wastewater. If a land applier is applying manure and/or wastewater such that lie or she is not
eligible for Jhe agricultural storm water discharge exemption and if the receiving waterbody (into
which there are storm water discharges associated with manure and/or wastewater) is not meeting
water quality standards for a pollutant in the waste (such as phosphorus, nitrogen, dissolved
oxygen, or fecal coliforms), EPA could propose that, by regulation, such a discharge constitutes a
"significant contributor of pollutants." For example, if a land applier is applying manure and/or
wastewater at a rate above the rate that qualifies the recipient for the agricultural storm water
discharge exemption, and if, due to precipitation, waste runs off the land application area through
a ditch into a navigable water that is impaired due to nutrients, the permit authority may designate
that point source as a regulated storm water point source. The designee would then need to apply
for an NPDES permit or risk being subject to enforcement actions for unpermitted discharges.
9.7 NPDES Reporting and Recordkeeping Requirements
The section of the NPDES permit on monitoring and reporting requirements identifies the
specific conditions related to the types of monitoring to be performed, the frequencies for
collecting samples or data, and how to record, maintain, and transmit the data and information to
the permit authority. This information allows the NPDES permit authority to determine
compliance with the permit requirements.
EPA is proposing revisions to the effluent guidelines that would require the operator to conduct
periodic visual inspection and to maintain all manure storage and handling equipment and
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structures, as well as all runoff management devices. The NPDES permit would also require the
permittee to (1) test and calibrate all manure application equipment annually to ensure that
manure is land applied in accordance with the proper application rates established in the NPDES
permit; (2) sample manure for nutrient content at least once annually, and up to twice annually if
manure is applied more than once or removed to be sent off-site more than once per year; and (3)
sample sorts for phosphorus once every 3 years. The proposed effluent guidelines would also
require the operator to review the PNP annually and amend it if practices change either at the
production area or at the land application area and submit notification to the permit authority.
Examples of changes in practice necessitating a PNP amendment include a substantial increase in
animal numbers (e.g., more than 20 percent) that would significantly increase the volume of
manure and nutrients produced on the CAFO; a change in the cropping program that would
significantly alter land application of animal manure and wastewater; elimination or addition of
fields receiving animal waste application; or changes in animal waste collection, storage
facilities, treatment, or land application method.
CAFO operators would be required to submit their PNPs, as well as any information necessary to
determine compliance with then- PNPs and other permit requirements, to the permit authority
upon request. The CAFO operator would also be required to make a copy of the PNP cover sheet
and executive summary available to the public in any of several ways. Operators of new facilities
seeking coverage under a general permit and applicants for individual permits would be required
to submit a copy of their draft PNP cover sheet and executive summary to the permit authority at
me time of NOI submittal or application.
EPA is also proposing to require operators to submit a written notification to the permit authority,
signed by the certified planner, that the PNP has been developed or amended and is being
implemented, accompanied by a fact sheet summarizing certain elements of the PNP. This
written notice of PNP availability would play an important role in verifying that the permittee is
complying with one of the requirements of the NPDES permit.
9.7.1 PNP Notification
EPA is proposing to require that applicants for individual permits and operators of new facilities
submitting notices of intent for coverage under a general permit submit a copy of the draft PNP
cover sheet and executive summary to the permit authority at the time of application or NOI
submittal (§§122.21(i)(l)(iv) and 122.28(b)(2)(ii)). Operators of existing facilities seeking
coverage under a general permit must submit a notice of final PNP development within 90 days
of seeking coverage but are not required to provide a copy of the PNP to the permit authority
unless requested. The reporting requirements,, including the notice of PNP development and
notice of PNP amendment, are discussed in more detail in preamble section VH.E.3.
.Initial installation of manure control technologies is significantly less costly than retrofitting
existing facilities, and early development of a PNP will help to ensure that, when a new facility is
being designed, the operator is considering optimal control technologies. In addition, in
situations where individual permits are warranted, the public interest demands early review of the
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summary of the PNP, rather than waiting for its ayailability after the permit has been in effect for
some time.
EPA is proposing that the permit authority be required, upon request from the public, to obtain a
copy of the PNP cover sheet and executive summary and make it available to the public if it is not
available by other means. The CAFO operator would be required to provide a copy to the permit
authority unless the operator has made it available through other means. For example, the CAFO
operator may choose to (1) maintain a copy of the PNP cover sheet and executive summary at the
facility and make it available to the permit authority as a publicly viewable document upon
request; (2) maintain a copy of the PNP cover sheet and executive summary at the facility and
make it available directly to the requestor, (3) place a copy of the PNP cover sheet and executive
summary at a publicly accessible site, such as a public library; or (4) submit a copy to the permit
authority. It is important to ensure that the public has access to information needed to determine
whether a CAFO is complying with its permit, including the land application provisions.
9.7.2 Certification from Non-CAFO Recipients of CAFO-Generated Manure
Inappropriate land application of CAFO-generated manure poses a significant risk to water
quality. Further, EPA estimates that the majority of CAFO-generated manure is in excess of
CAFO's crop needs and will very likely be transferred off-site. The ultimate success of the
CAFO program depends on whether recipients handle manure appropriately and in_a manner that
prevents discharge to waters.
EPA considered a range of approaches including no consideration of off-site manure transfer,
basic recordkeeping, and reporting requirements; requiring certification from manure recipients
that they will apply the manure using proper agricultural practices; and requiring certification
from the manure recipient that a nutrient management plan has been written and implemented by
the recipient To estimate the number of recipients needed to accept manure transferred off-site,
EPA used the following baseline assumptions:
• Hauling of excess manure is paid for by the CAFO.
• Crop farmers already maintain records and have a nutrient management plan, though the
plan is not necessarily a certified CNMP.
• Recipients will apply manure at nitrogen rate; i.e., assume that the crop farmer will accept
manure only if spreading is on a nitrogen basis.
• To calculate the amount of excess manure generated at CAFOs, excess manure nitrogen
was obtained from a USD A analysis of 1997 census data (Kellogg et al., 2000).
• To calculate the number of farms needed to properly apply excess manure, the average
crop farm size was assumed to be 487 acres (per 1997 Census of Agriculture summary
statistics).
• Fifty four percent of crop farmers already sample soils every 3 years (CTIC, 2000).
Costs include soil sampling and incremental recordkeeping costs identical to those costs
developed for CAFOs in Chapter 11. They include $10 labor and $10 analytical costs for every
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10 acres of cropland. For upper-bound costs an additional cost of $5 per acre was included if a
full PNP or CNMP is written by the recipient as a result of this requirement. Setbacks for manure
spreading are not included. Training and certification for manure spreaders costs $117, as
identified in Chapter 11. Calibration of manure spreading equipment is paid for by the CAFO.
The following table presents the range of costs for various approaches to managing manure
transferred off-site.
Table 35. Recipients and Costs for Off-Site Locations Receiving Manure from CAFOs
Number of off-site manure recipients
Cost per recipient for records
Total costs to all recipients for records
Upper-bound costs for nutrient plan
(assuming PNP or CNMP development)
NPDES Scenario (Definition of CAFO)
> 1,000 AU
13,489
$994
$7.2 million
$33.1 million
>#500AU
17,923
$994
$9.6 million
$44.0 million
>#300AU
21,155
$994
$11. 3 million
$51.9 million
IS
EPA is not proposing to regulate off-site recipients through CAFO permit requirements; however,
EPA is proposing two alternatives for ensuring that CAFO-generated manure that is transferred to
off-site recipients is managed to prevent water quality impairment. In the first alternative, EPA i
proposing certain certification and recordkeeping requirements to help ensure responsible'
handling of manure. In the second alternative, EPA is proposing recordkeeping requirements
only.
In the first alternative, EPA is proposing to require CAFO operators to obtain a certification from
recipients (other than manure haulers that do not land apply the waste) of more than 12 tons per
year of CAFO-generated manure and wastewater certifying the recipients will, do one of the
following: (1) land apply according to proper agricultural practices (which the proposal would
define to mean that the recipient determines the nutrient needs of its crops based on realistic crop
yields for its area, sample its soil at least once every 3 years to determine existing nutrient
content, and does not apply the manure in quantities that exceed the land application rates
calculated using one of the methods specified in the proposed rule); (2) obtain an NPDES permit
for discharges resulting from nonagricultural land application; or (3) utilize the manure for
purposes other than land application. (See proposed § 122.23(j)(4)).
EPA is proposing both requirements: (1) that CAFOs obtain a certification and (2) that recipients
of CAFO-generated manure so certify, pursuant to section 308 of the CWA. Under section 308,
EPA has the authority to require the owner or operator of a point source to establish and maintain
records and provide any information the Agency reasonably requires. The Agency has
documented historic problems associated with overapplication of CAFO waste by both CAFO
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operators and recipients of CAFO waste. The proposal would establish effluent limitations
designed to prevent discharges due to overapplication. To determine whether CAFOs are
meeting the effluent limitations that would be established under the proposals, EPA believes it is
necessary for the Agency to have access to information concerning where a CAFO's excess
manure is sent. Furthermore, to determine whether the recipients of CAFO manure should be
permitted (which might be required if they do not land apply the CAFO manure in accordance
with proper agricultural practices arid they discharge from a point source), EPA has determined
that it will be necessary for such recipients to provide information about their land application
methods. Recipients who certify that they are applying manure in accordance with proper
agricultural practices are responding to a request under section 308 of the CWA. Therefore., a
recipient who falsely certifies is subject to all applicable civil and criminal penalties under section
309 of the CWA.
In some cases, CAFOs give or sell manure to many different recipients, including those taking
small quantities, and this requirement could result in an unreasonable burden. EPA is primarily
concerned with recipients who receive and dispose of large quantities, presuming that recipients
of small quantities pose less risk of inappropriate disposal or overapplication. To relieve the
paperwork burden, EPA is proposing that CAFOs not be required to obtain certifications from
recipients that receive less than 12 tons of manure per year from the CAFO. The CAFO would,
however, be required to keep records of transfers to such recipients, as describe below.
The Agency believes that it would be reasonable to exempt from the PNP certification
requirements recipients who receive small amounts of manure from CAFOs. EPA considered
exempting amounts such as a single truckload per day or a single truckload per year. EPA
decided that an appropriate exemption would be based on an amount that would typically be used
for personal, rather than commercial, use. The exemption in the proposed regulation is based on
the amount of manure that would be-appropriately applied to 5 acres of land because 5 acres is at
the low end of the amount of land that can be profitably farmed. See, for example, "The New
Organic Grower," Eliott Coleman (1995)).
To determine the maximum amount of manure that could be appropriately applied to five acres of
land, an average nutrient requirement per acre of cropland and pastureland was computed. Based
on typical crops and national average yields, 160 pounds of nitrogen (N) and 14.8 pounds of
phosphorus (P) are required annually per acre. See Manure Nutrient Relative to the Capacity of
Cropland and Pastureland to Assimilate Nutrients, (USDA, 2000). The nutrient content of
manure was based on a USDA-NRCS (1998) report, Nutrients Available from Livestock Manure
Relative to Crop Growth Requirements.
The nitrogen content of manure at the time of land application ranges from 1.82 pounds per ton
for heifers and dairy calves to 18.46 pounds per ton for hens and pullets. Using the low-end rate
of 1.82 pounds of nitrogen per ton, 87.4 tons of manure would be needed for a typical acre, or
439 tons of manure for 5 acres, to achieve the 160 pounds per acre rate. Using the high-end rate
of 18.46 pounds of nitrogen per ton, 8.66 tons of manure would be needed for a typical acre, or
43.3 tons of manure for 5 acres, to achieve the 160 pounds per acre rate. Thus, the quantity of
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manure needed to meet the nitrogen requirements of a 5 acre plot would range from 43.3 tons to
439 tons, depending on the animal type.
The phosphorus content of manure at the time of land application ranges from 1.10 pounds per
ton for heifers and dairy calves to 11.23 pounds per ton for turkeys for breeding. Using the high-
end 11.23 pound per ton rate for phosphorus, only about 1.3 tons would be needed for an average
acre, or 6.5 tons for 5 acres, to meet the 14.8 pounds of phosphorus required annually for a typical
acre of crops. Using the low-end 1.1 pound per ton rate for phosphorus, about 13.2 tons would be
needed for an average acre, or 66 tons for 5 acres. Using the phosphorus content for broilers of
6.61 pounds per ton is more typical of the content of manure and would result in 2.23 tons per
acre being needed for an average acre, or 11.2 tons for 5 acres.
Clearly, exempting the high-end amount of manure based on nitrogen content could lead to
excess application of phosphorus. Regulating based on the most restrictive P requirement could
lead to manure not being available for personal use. The exemption is only an exemption from
the requirement that the CAFO obtain a certification. The recipient would remain subject to any
requirements of state or federal law to prevent discharge of pollution to waters of the United
States.
EPA is proposing to set the threshold at 12 tons per recipient per year. This is rounding the
amount based on typical P content. It also allows 1 ton pickup load per month, which is
consistent with one of the alternative approaches EPA considered. Recipients that receive more
than 12 tons would have to certify that the waste will be properly managed.
For CAFO owners or operators who transfer CAFO-generated manure and wastewater to manure
haulers who do not land apply the waste, EPA is proposing that the CAFO owner or operator
must (1) obtain the name and address of the recipients, if known; (2) provide the manure hauler
with an analysis of the nutrient content of the manure, to be provided to the recipients; and (3)
provide the manure hauler with a brochure to be given to the recipients describing the recipients'
responsibility to properly manage the land application of the manure to prevent discharge of
pollutants to waters of the United States.
In the second alternative proposal for ensuring proper management of manure that is transferred
off-site, EPA is not proposing to require CAFO owners or operators to obtain the certification
described above. Rather, CAFO owners or operators would be required to maintain records of
transfer. ......
Concern has been expressed that many potential recipients of CAFO manure will choose to
forego CAFO manure and buy commercial fertilizers instead to avoid signing such a certification
and being brought under EPA regulation. The result could be that CAFO owners and operators
might be unable to find a market for proper disposal, thereby turning the manure into a waste
rather than a valuable commodity.
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This alternative is potentially protective of the environment because non-CAFO land appliers
would be liable for being designated as a point source in the event that there is a discharge from
improper land application. EPA's proposed requirements for what constitutes proper agricultural
practices would ensure that CAFO-generated manure is properly managed. •
9.8 References
Allen, P. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. May 19.
Bickert,W. 1999. Record of communication CAFO permitting rule. Telephone conversation
with R. Johnson, DPRA, Alexandria, Virginia. May 18.
Bracht, G. 1999. Regarding the CAFO Questions. E-mail message to DPRA, .Arlington,
Virghinia. November 15.
Bredencamp, T. 1999. Facility Comments - Draft Final SVR - Nebraska Site Visits. E-mail
message to DPRA, Arlington, Virginia. August 16.
Byron, T. 1999. Regarding the CAFO Questions. E-mail message to DPRA, Arlington, Virginia.
November 12.
Carey, J.B. 1999. Swine and Poultry Survey. E-mail message to DPRA, Arlington, Virginia. April
16.
Clark, J. 1999. KDHE response. E-mail message, to DPRA, Arlington, Virginia, April 13.
Coleman, E. 1995. The organic grower: a master's manual of tools and techniques for the home
and market gardener. United States.
CTIC. 2000. Nutrient management research. Prepared for the Conservation Technology
Information Center by Marketing Directions.
Ernst, R. 1999. Regarding Estimates on the Percentage of Swine Facilities. E-mail message to
DPRA, Arlington, Virginia. November 11.
Foley, G. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. April 14.
Funk, T. 1999. FYI. E-mail message to DPRA, Arlington, Virginia. November 23.
Gale, J.A. 1999. Utah - response. E-mail message to DPRA, Arlington, Virginia. May 5.
Greenless, W. 1999. Completed Survey—Iowa. E-mail message from J. Blair, DPRA,
Alexandria, Virginia. April 27.
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Groves, R. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. May 14.
Gunter, T. 1999. Regarding the Requested Numbers of CAFO Operations with 300 to 1000
Animal Units. E-mail message to DPRA, Arlington, Virginia. December 7.
Harrelson. 1999. KS Beef. E-mail message from C. Simons, DPRA, Alexandria, Virginia. August
16.
Holmes, B. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. May
Jacobson, L.D. 1999. Survey Response - MN. E-mail message to DPRA, Arlington, Virginia.
April 14.
Johnson, D. 1999. Regarding responses and questions for the dairy industry. E-mail message to
DPRA, Arlington, Virginia. May 17.
Kauz Loric, P. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. May
Kellogg, R.L., C.H. Lander, D. Moffitt, and N. Gollehon. 2000. Manure nutrients relative Jo the
capacity of cropland and pastureland to assimilate nutrients: Spatial and temporal trends
for the United States. U.S. Department of Agriculture, Natural Resources Conservation
Service, Washington DC. • • - .
Lory, J. 1999. Feeding Operations. E-mail message to DPRA, Arlington, Virginia. April 16.
Malone, G. 1999. Record of Communication. Memorandum to DPRA, Arlington, Virginia.
November 19.
NCDENR. 1999 Lagoon closure information. North Carolina Department of Environmental and
Natural Resources, Division of Soil and Water Conservation. Raleigh, North Carolina.
Nicholson, B. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. April
16.
Orth, R. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia. May 17.
Patterson, P. 1999. Record of Communication. E-mail message to DPRA, Arlington, Virinia
March 25. -
Ramsey, D. 1999. CAFOs. E-mail message to DPRA, Arlington, Virginia. March 2.
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SAIC. 1999. Aggregated ARMS financial data received by USDA, ERS, and spreadsheet
versions of files converted by M. Beljak: May 7.
SAIC. 2000. Memorandum: Federal wage rate discrepancy between CAFO documents. S.
Ragland and T. Carpenter, Science Applications International Corporation. May 30.
Steinhart, T. 1999. Answers to recent questions - Iowa. E-mail message to DPRA. Arlington,
Virginia. April 15.
Teague, F. 1999. CAFO Permitting Rule. E-mail message to DPRA, Arlington, Virginia, May 17.
Thomas, J. 1999. Completed Survey - MS. E-mail message to DPRA, Arlington, Virginia. April
15.
Tyson, T.W. 1999. Survey response - Alabama. E-mail message to DPRA, Arlington, Virginia.
April 22.
USDA NRCS. 1998. Nutrients available from livestock manure relative to crop growth
requirements. U.S. Department of Agriculture, Natural Resources Conservation Service,
Washington DC.
USDA NRCS. 1998. National Handbook of Conservation Practices. U.S. Department of
Agriculture, Natural Resources Conservation Service, Washington DC.
USDA NRCS. 2000. National handbook of conservation practices. U.S. Department of
Agriculture, Natural Resources Conservation Service, Washington DC.
USEPA. 1995. Guidance manual on NPDES regulations for concentrated animal feeding
operations. EPA 833-B-95-001. U.S. Environmental Protection Agency, Washington,
DC.
USEPA. 1999. State Compendium: Programs and regulatory activities related to animal feeding
operations. U.S. Environmental Protection Agency, Washington, DC.
Wilson, R. 19991. Questions Regarding Beef Feeding Industry. E-mail message to DPRA,
Arlington, Virginia. • .
York, K. 1999. CAFO Permitting. E-mail message to DPRA, Arlington, Virginia. March 3..
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CHAPTER 10
TECHNOLOGY OPTIONS CONSIDERED
10-1 Changes to Effluent Guidelines Applicability
The existing effluent guidelines regulations for feedlots apply to operations with 1,000 AU and
greater. EPA is proposing to establish effluent guidelines requirements for the beef, dairy, swine,
chicken and turkey subcategories that would apply to any operations in these subcategories that '
are defined as a CAFO under either the two-tier or three-tier structure.
EPA also proposes to establish a new subcategoiy that applies to the production of veal cattle.
Veal production is currently included in the beef subcategory. However, veal production
practices and wastewater and manure handling are very different from the practices, used at beef
feedlots; therefore, EPA proposes to establish a separate subcategory for veal.
Under the three-tier structure the proposed effluent guidelines requirements for the beef, dairy,
swine, veal and poultry subcategories will apply to all operations defined as GAFOs by today's
proposal having at least as many animals as listed below.
200 mature dairy cattle (whether milked or dry); --•-'-
300 veal cattle;
300 cattle other than mature dairy cattle or veal;
750 swine weighing over 55 pounds;
3,000 swine weighing 55 pounds or less;
16,500 turkeys; or
30,000 chickens.
Under the two-tier structure, the proposed requirements for the beef, dairy, swine, veal and
poultry subcategories will apply to all operations defined as CAFOs by today's proposal having
at least as many animals as listed below. .
350 mature dairy cattle (whether milked or dry);
500 veal cattle;
500 cattle other than mature dairy cattle or veal;
1,250 swine weighing over 55 pounds;
5,000 swine weighing 55 pounds or less;
27,500 turkeys; or
50,000 chickens.
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EPA is proposing to apply the effluent guidelines requirements for the beef, dairy, veal, swine,
chicken and turkey subcategories, to all operations in these subcategories that are defined as
CAFOs under either of these permitting scenarios. Operations below the 500 AU threshold or
the 300 AU threshold in the three-tier structure that are designated as CAFOs are not subject to
the proposed effluent guidelines.
EPA has evaluated the technology options described in this section and evaluated the economic
achievability for these technologies for all operations with at least as many animals listed above
for both the two-tier and three-tier NPDES structures. The technology requirements for
operations defined as CAFOs under the two-tier structure are the same reqmrements for
operations defined as CAFOs under the three-tier structure.
10.2 Changes to Effluent Limitations and Standards
EPA is proposing to revise BAT and new source performance standards for the beef, dairy, veal,
swine and poultry subcategories. EPA is proposing to establish technology-based limitations on
land application of manure to lands owned or operated by the CAFO, maintain the zero discharge
standard and establish management practices at the production area.
10.2.1. Current Requirements
The existing regulations, which apply to operations with 1,000 AU or greater, require zero
discharge of wastewater pollutants from the production area. Discharge is allowed when rainfall
events, either chronic or catastrophic cause an overflow of process wastewater from a facility
designed, constructed and operated to contain all process generated wastewaters plus runoff from
a specific storm event. The magnitude of the storm event depends varies on the requirement, for
the existing BPT requirements EPA established the design criteria on the 10-year, 24-hour event
and based the existing BAT and New Source requirements on a 25-year, 24-hour storm event. In
other words, wastewater and wastewater pollutants are allowed to be discharged as the result of a
chronic or catastrophic rainfall event so long as the operation has designed, constructed and
operated a manure storage and/or runoff collection system to contain all process generated
wastewater, including the runoff from a specific rainfall event. The effluent guidelines do not set
discharge limitations on the pollutants in the overflow.
10.2.2. Best Practicable Control Technology Limitations Currently Available (BPT)
EPA is proposing to establish BPT limitations for the beef, dairy, swine, veal chicken and turkey
subcategories. There are BPT limitations in the existing regulations which apply to CAFOs with
1,000 AU or more in the beef, dairy swine and turkey subcategories. BPT requires that these
operations achieve zero discharge of process wastewater from the production area except in the
event of a 10-year, 24-hour storm event. EPA is proposing to revise this BPT requirement and to
expand the applicability of BPT to all operations defined as CAFOs in these subcategories
including CAFOs with fewer than 1,000 AU.
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The Clean Water Act requires that BPT limitations reflect the consideration of the total cost of
application of technology in relation to the effluent reduction benefits to be achieved from such
applications. EPA considered two options as the basis for BPT limitations.
Option 1. This option would require zero discharge from a facility designed, maintained and
operated to hold the waste and wastewater, including storm water, from runoff plus the 25-year
24-hour storm event. Both this option and Option 2 would add record keeping requirements and
practices that ensure this zero discharge standard is met. As described in Section V there are
numerous reports of operations discharging pollutants from the production area during dry
weather. The reason for these discharges varies from intentional discharge to poor maintenance
of the manure storage area or confinement area. As described in Chapter 11 and in the cost
methodology appendices, EPA's cost models reflect the different precipitation and climatic
factors that affect an operations ability to meet this requirement.
Option 1 would require weekly inspection to ensure that any storm water diversions at the animal
confinement and manure storage areas are free from debris, and daily inspections of the
automated systems providing water to the animals to ensure they are not leaking or spilling. The
manure storage or treatment facility would have to be inspected weekly to ensure structural
integrity. For liquid impoundments, the berms would need to be inspected for leaking, seepage,
erosion and other signs of structural weakness. The proposal requires that records of these
inspections would be maintained on-site, as well as records documenting any problems noted and
corrective actions taken. EPA believes these inspections are necessary to ensure proper
maintenance of the production area and prevent discharges apart from those associated with a
storm event from a catastrophic or chronic storm. ..',.,.
Liquid impoundments (e.g., lagoons, ponds and tanks) that are open and capture precipitation
would be required to have depth markers installed. The depth marker indicates the maximum
volume that should be maintained under normal operating conditions allowing for the volume
necessary to contain the 25-year, 24-hour storm event. The depth of the impoundment would
have to be noted during each week's inspection and when the depth of manure and wastewater in
the impoundment exceeds this maximum depth, the operation would be required to notify the
Permit Authority and inform him or her of the action that will be taken to address this
exceedance. Closed or covered liquid impoundments must also have depth markers installed,
with the depth of the impoundment noted during each week's inspection. In all cases, this liquid
may be land applied only if done in accordance with the permit nutrient plan (PNP) described
below. Without such a depth marker, a CAFO operator may fill the lagoons such that even a
storm less than a 25-year, 24-hour storm causes the lagoon to overflow, contrary to the discharge
limit proposed by the BPT requirements.
Option 1 would require operations to handle dead animals in ways that prevent contributing
pollutants to waters of the U.S. EPA proposes to prohibit any disposal of dead animals in any
liquid impoundments or lagoons. The majority of operations have mortality handling practices
10-3
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that prevent contamination of surface water. These practices include transferring mortality to a
rendering facility, 'burial in properly sited lined pits, and composting.
Option 1 also would establish requirements to ensure the proper land application of manure and
other process wastes and wastewaters. Under Option 1 land application of manure and
wastewater to land owned or operated by the CAFO would have to be performed in accordance
with a PNP that establishes application rates for manure and wastewater based on the nitrogen
requirements for the crop. Pollutants in runoff are directly related to quantity of chemicals or
fertilizer applied. EPA believes that application of manure and wastewater in excess of the
crop's nitrogen requirements would increase the pollutant runoff from fields.
In addition, Option 1 includes a requirement that manure be sampled at least once per year and
analyzed for its nutrient content including nitrogen, phosphorus and potassium. EPA believes
that annual sampling of manure is the minimum frequency to provide the necessary nutrient
content on which to establish the appropriate rate. If the CAFO applies its manure more
frequently than once per year, it may choose to sample the manure more frequently. Sampling
the manure as close to the time of application as practical provides the CAFO, with a better
measure of the nitrogen content of the manure. Generally, nitrogen content decreases through
volatilization during manure storage when the manure is exposed to air.
The manure application rate established in the PNP would have to be based on the following
factors: (1) the nitrogen requirement of the crop to be grown based on the agricultural extension
or land grant university recommendation for the operation's soil type and crop; and (2) realistic
crop yields that reflect the yields obtained for-the given field in prior years or, if not available,
from yields obtained for same crop at nearby farms or county records. Once the nitrogen
requirement for the crop is established the manure application rate would be determined by
subtracting any other sources of nitrogen available to the crop from the crop's nitrogen
requirement These other sources of nitrogen can include residual nitrogen in the soil from
previous applications of organic nitrogen, nitrogen credits from previous crops of legumes, and
crop residues, or applications of commercial fertilizer, irrigation water and biosolids.
Application rates would be based on the nitrogen content hi the manure and should also account
for application methods, such as incorporation, and other site specific practices.
The CAFO would have to maintain the PNP on-site, along with records of the application of
manure and wastewater including: (1) the amount of manure applied to each field; (2) the
nutrient content of manure; (3) the amount and type of commercial fertilizer and other nutrient
sources applied; and (4) crop yields obtained. Records must also indicate when manure was
applied, application method and weather conditions at the time of application.
While Option 1 would require manure to be sampled annually, it would not require soil sampling
and analysis for the nitrogen-content in the soil. Nitrogen is present in the soil in different forms
and depending on the form the nitrogen will have different potential to move from the field.
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Nitrogen is present in an organic form from the decay of proteins and urea found in livestock
manure and biosolids, or from other organic compounds that result from decaying plant material
These organic compounds are broken down by soil bacteria to inorganic forms of nitrogen such
as nitrate and ammonia. Inorganic nitrogen or urea may be applied to crop or pasture land as
commercial fertilizer. Inorganic nitrogen is the form taken up by the plant. It is also more
soluble and readily volatile, and can leave the field through runoff or emissions. Nitrogen can
also be added to the soil primarily through cultivation of legumes which will "fix" nitrogen in the
soil. At all times nitrogen is cycling through the soil, water, and air, and does not become
adsorbed or built up in the soil in the way that phosphorus does, as discussed under Option 2.
Thus, EPA is not proposing to require soil sampling for nitrogen. EPA would, however, require
that, in developing the appropriate application rate for nitrogen, any soil residue of nitrogen
resulting from previous contributions by organic fertilizers, crop residue or legume crops should
be taken into account when determining the appropriate nitrogen application rate. State
Agricultural Departments and Land Grant Universities have developed methods for accounting
for residual nitrogen contributed from legume crops, crop residue and organic fertilizers.
Option 1 would also prohibit application of manure and wastewater within 100 feet of surface
waters, tile drain inlets, sinkholes and agricultural drainage wells. EPA strongly encourages
CAFOs to construct vegetated buffers, however, Option 1 only prohibits applying manure within
100 feet of surface water and would not require CAFOs to take crop land out of production to
construct vegetated buffers. CAFOs may continue to use land within 100 feet of surface water to
grow crops.,
Under Option 1, EPA included costs for facilities to construct minimal storage, typically three to
six months, to comply with the manure application rates developed in the PNP. Data indicate
that when the manure has-been-stored and aged prior to land application, pathogen
"concentrations" in surface waters adjacent to land that received manure does not vary
significantly from pathogen "concentrations" adjacent to land that did not receive manure. In
addition to pathogen reductions achieved through storage, EPA believes the 100 foot setback and
proper manure application, will minimize the potential runoff of pathogens, hormones and metals
and reduce the nutrient and sediment runoff.
EPA chose not to propose requiring operations to take land out of production and construct a
vegetated buffer because a buffer may not be the most cost-effective application to control
erosion in all cases. There are a variety of field practices that should be considered for the
control of erosion. EPA encourages CAFOs to obtain and implement a conservation
management plan to minimize soil losses, and also to reduce losses of pollutant bound to the
soils. Erosion and sediment controls are discussed in Chapter 8.
Today's proposal requires a greater setback distance than the distance that would be needed for a
cost effective buffer under most circumstances. Since EPA is not requiring the construction of a
vegetated buffer, the additional setback distance will compensate for the loss of pollutant
10-5
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reductions in the surface runoff leaving the field that would have been achieved with a vegetated
buffer without requiring CAFOs to remove this land from production.
Farmers entering stream buffers hi the Conservation Reserve Program's (CRP) Continuous Sign-
Up receive bonus payments, as an added incentive to enroll, include a 20 percent rental bonus, a
S100 per acre payment up-front (at the time they sign up), and another bonus at the time they
plant a cover. These bonus payments more than cover costs associated with enrolling stream
buffers, (i.e., rents forgone for the duration of their 10 or 15 year CRP contracts, and costs such
as seed, fuel, machinery and labor for planting a cover crop). The bonuses provide a
considerable incentive to enroll stream buffers because the farmers receive payments from
USDA well in excess of what they could earn by renting the land for crop production. Farmers
can enter buffers into the CRP program at any time.
EPA may also consider providing CAFOs the option of prohibiting manure application within
100 feet or constructing a 35 foot vegetated buffer. As discussed in more detail in Chapter 11 and
the cost methodology appendices, the cost associated with taking land out of production and
planting with a vegetated buffer is included in the cost for Option 1 and all subsequent options,
even though it is not a requirement. Chapter 8 describes the application of a buffer and its
advantages and disadvantages.
Option 1 is estimated to cost $432.1 million annually for all operations defined as CAFOs under
the two-tier structure and $462.8 milh'on annually for all operations defined as CAFOs under the
three-tier structure. These estimates account for practices and technologies already in place at
operations and thus represent the incremental costs that would be incurred by. operations to
comply with the requirements of Option 1. Option 1 is estimated to reduce nutrient loads
reaching the edge of the field amounting to 624 million pounds under the three-tier structure.
Option 1 is also estimated to achieve a 37 million pound reduction of the metals reaching the
edge of the field and reduce fecal coliform by 135 billion colony forming units (cfu) and fecal
streptococcus by 218 billion cfu under the three-tier structure. Under the two-tier structure the
reductions are estimated to be 553 million pounds of nutrients, 31 million pounds of metals and
116 billion cfu, and 206 billion cfu of fecal coliforms and streptococcus, respectively.
Option 2. Option 2 retains all the same requirements for the feedlot and manure storage areas
described under Option 1 with one exception: Option 2 would impose a BMP that requires
manure application rates be phosphorus based where necessary, depending on the specific soil
conditions at the CAFO.
Manure is phosphorus rich, so application of manure based on a nitrogen rate may result in
application of phosphorus in excess of crop uptake requirements. Traditionally, this has not been
a cause for concern, because the excess phosphorus does not usually cause harm to the plant and
can be adsorbed by the soil where it was thought to be strongly bound and thus environmentally
benign. However, the capacity for soil to adsorb phosphorus will vary according to soil type, and
recent observations have shown that soils can and do become saturated with phosphorus. When
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saturation occurs, continued application of phosphorus in excess of what can be used by the crop
and adsorbed by the soil results in the phosphorus leaving the field with storm water via leaching
or runoff. Phosphorus bound to soil may also be lost from the field through erosion.
Repeated manure application at a nitrogen rate has now resulted in high to excessive soil
phosphorus concentrations in some geographic locations across the country. Option 2 would
require manure application be based on the crop removal rate for phosphorus in locations where
soil concentrations or soil concentrations in combination with other factors indicate that there is .
an increased likelihood that phosphorus will leave the field and contribute pollutants to nearby
surface water and groundwater. Further, when soil concentrations alone or hi combination with
other factors exceed a given threshold for phosphorus, the proposed rule would prohibit manure
application. EPA included this restriction because the addition of more phosphorus under these
conditions is unnecessary for ensuring optimum crop production.
Nutrient management under Option 2 includes all the steps described under Option 1, plus the
requirement that all CAFOs collect and analyze soil samples at least once every 3 years from all
fields that receive manure. EPA would require soil sampling at 3 year intervals because this
reflects a minimal but common interval used in crop rotations. This frequency is also commonly
adopted in nutrient management plans prepared voluntarily or under state programs. When soil
conditions allow for manure application on a nitrogen basis, then the PNP and record keeping
requirements are identical to Option 1. Permit nutrient plans would have to be reviewed and
updated each year to reflect any changes in crops, animal production, or soil measurements and
would be rewritten and certified at a minimum of once every five years or concurrent with each
permit renewal, .
The CAFO's PNP would have to reflect conditions that require manure application on a
phosphorus crop removal rate. The manure application rate based on phosphorus requirements
takes into account the amount of phosphorus that will be removed from the field when the crop is
harvested. This defines the amount of phosphorus and the amount of manure that may be applied
to the field. The PNP must also account for the nitrogen requirements of the crop. Application
of manure on a phosphorus basis will require the addition of commercial fertilizer to meet the
crop requirements for nitrogen. Under Option 2, EPA believes there is an economic incentive to
maximize proper handling of manure by conserving nitrogen and minimizing the expense
associated with commercial fertilizer. EPA expects manure handling and management practices
will change in an effort to conserve the nitrogen content of the manure, and encourages such
practices since they are likely to have the additional benefit of reducing the nitrogen losses to the
atmosphere.
EPA believes management practices that promote nitrogen losses during storage will result in
higher applications of phosphorus because in order to meet the crops requirements for nitrogen a
larger amount of manure must be applied. Nitrogen volatilization exacerbates the imbalance in
the ratio of nitrogen to phosphorus in the manure as compared to the crop's requirement. Thus
application of manure -to meet the nitrogen requirements of the crop will result in over
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application of phosphorus and the ability of the crops and soil to assimilate phosphorus will
reach a point at which the facility must revise the PNP to reflect phosphorus based application
rates.
Under both Option 1 (N) and Option 2 (P), the application of nitrogen from all sources may not
exceed the crop nutrient requirements. Since a limited amount of nutrients can be applied to the
field in a given year, EPA expects facilities will select the site-specific practices necessary to
optimize use of those nutrients. Facilities that apply manure at inappropriate times run the risk of
losing the value of nutrients applied and will not be permitted to reapply nutrients to compensate
for this loss. Consequently crop yields may suffer, and in subsequent years, the allowable
application rates will be lower. For these reasons, facilities with no storage are assumed to need
a iriinimal storage capacity to allow improved use of nutrients. Costs were estimated for
operations which do not currently have adequate storage, see Chapter 11 and the cost
methodology appendices for a discussion of how these costs were determined and how many
operations were costed for this requirement.
Option 2 provides three methods for determining the manure application rate for a CAFO. These
three methods are:
• Phosphorus Index
• Soil Phosphorus Threshold Level
• Soil Test Phosphorus Level .. ..,,. ... , .-
These three methods are adapted from NRCS' nutrient management standard (Standard 590),
which is being used by States' Departments of Agriculture to develop State nutrient standards
that incorporate one or a combination of these three methods. EPA is proposing to require that
each authorized state Permit Authority adopt one or a combination of these three methods in
consultation with the State Conservationist. CAFOs would then be required to develop their
.PNP based on the State's method for establishing the application rate. In those states where EPA
is the permitting authority, the EPA Director would adopt one of these three methods in
consultation with that State's Conservationist.
Phosphorus Index - This index assesses the risk that phosphorus will be transported off the field
to surface water and establishes a relative value of low, medium, high or very high, as specified
in §412.33. Alternatively, it may establish a numeric ranking. At the present tune there are
several versions of the P-Ladex under development. Many states are working on a P-rndex for
their state in response to the NRCS 590 Standard, and NRCS itself developed a P-Index template
in 1994 and is in the process of updating that template at the present time. There are efforts
underway in the scientific communiry to standardize a phosphorus index and assign a numeric
ranking.
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At a minimum the phosphorus index must consider the following factors:
• soil erosion
• irrigation erosion
• runoff class
• soil P test
• P fertilizer application rate-
• P fertilizer application method
• organic P source application rate
• organic P source application method
Other factors could also be included, such as:
•• subsurface drainage
• leaching potential •
• distance from edge of field to surface water
• priority of receiving water
Each of these factors is listed in a matrix with a score assigned to each factor. For example, the
distance from edge of field to surface water assigns a score to different ranges of distance. The
greater the measured distance, the lower the score. Other factors may not be as straightforward.
For example, the surface runoff class relates field slope and soil permeability in a matrix, and
determines a score for this element based on the combination of these factors. The same kind of
approach could also be used for the subsurface drainage class, relating soil drainage class with
the depth to the seasonal high water table. The values for all variables that go into determining a
P-hidex can either be directly measured, such as distance to surface water, or can be determined
by data available from the state, such as soil drainage class that is based on soil types found in the
state and assigned to all soil types. Finally, each factor is assigned a weight depending on its
relative importance in the transport of phosphorus.
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When a P-Index is used to determine the potential for phosphorus transport in a field and the
overall score is high, the operations would apply manure on a phosphorus basis (e.g., apply to
meet the crop removal rate for phosphorus). When a P-Ladex determines that the transport risk is
very high, application of manure would be prohibited. If the P-Index results in a rating of low or
medium, then manure may be applied to meet the nitrogen requirements of the crop as described
under Option 1. However, the CAFO must continue to collect soil samples at least every three
years. If the phosphorus concentration in the soil is sharply increasing, the CAPO may want to
considertoanaging its manure differently. This may include changing the feed, formulations to
reduce the amount of phosphorus being fed to the animals, precision feeding to account for
nutrient needs of different breeds and ages of animals. It may also include changing manure
storage practices to reduce nitrogen losses. These practices are discussed in detail in Chapter 8.
The CAFO may also consider limiting the application of manure. For example, the CAFO may
apply manure to one field to meet the nitrogen requirements for that crop but not return to that
field until the crops have assimilated the phosphorus that was applied from the manure
application.
Phosphorus Threshold - This threshold which would be developed for different soil types is a
measure of phosphorus hi the soil that reflects the level of phosphorus at which phosphorus
movement in the field is acceptable. Scientists are currently using a soluble phosphorus
concentration of 1 part per million (ppm) as a measure of acceptable phosphorus movement.
When the soil concentration of phosphorus reaches this threshold the concentration of ,
phosphorus in the runoff would be expected to be 1 ppm. The 1 ppm value has been used as an
indicator of acceptable phosphorus concentration because it is a concentration that has been
applied to POTWs in their NPDES permits. An alternative phosphorus discharge value could be
the water quality concentration for phosphorus in a given receiving stream.
States which adopt this method in their state nutrient management standard would need to
establish a phosphorus threshold for all types, of soils found in then- state.
Use of the phosphorus threshold in developing an application rate allows for soils with a
phosphorus concentration less than three quarters the phosphorus threshold to apply manure on a
nitrogen basis. When soils have a phosphorus concentration between 3/4 and twice the
phosphorus threshold then manure must be applied to meet the crop removal requirements for
phosphorus. For soils which have phosphorus concentrations greater than twice the phosphorus
threshold, no manure may be applied.
Soil Test Phosphorus — The soil test phosphorus is an agronomic soil test that measures for
phosphorus. This method is intended to identify the point at which the phosphorus concentration
in the soil is high enough to ensure optimum crop production. Once that concentration range
(often reported as a "high" value from soil testing laboratories) is reached, phosphorus is applied
at the crop removal rate. If the soil test phosphorus level reaches a very high concentration, then
no manure may be applied. Most soils need to be nearly saturated with phosphorus to achieve
10-10
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optimum crop yields. The soil phosphorus concentration should take into account the crop
response and phosphorus application should be restricted when crop yield begins to level off.
The soil test phosphorus method establishes requirements based on low, medium, high and very
high soil condition, and applies the same restrictions to these measures as are used in the P-
Index. States that adopt this method must establish the soil concentration ranges for each of
these risk factors for each soil type and crop in their state.
EPA anticipates that in most states, the permit authority will incorporate the State's nutrient
standard (590 Standard) into CAFO permits. For example, if the permit authority, in
consultation with the State Conservationist, adopts a Phosphorus Index, then CAFO permits
would include the entire P-Index as the permit condition dictating how the application rate must
be developed. If a permit authority selects the Phosphorus Threshold, then the CAFO permits
must contain soil concentration limitations that reflect phosphorus-based application, as well as
the level at which manure application is prohibited.
Finally; under Option 2 EPAIs proposing to require CAFOs that transfer manure off-site to
provide the recipient of the manure with information as to the nutrient content of the manure and
provide the recipient with information on the correct use of the manure.
EPA estimates Option 2 would cost $548.8 million annually for all operations defined as CAFOs
under the two-tier structure and $582.8 million annually under the three-tier structure. EPA
estimates that Option 2 will achieve reductions at the edge of field of 760 million pounds of
nutrients (nitrogen and phosphorus)under the two-tier structure and 860 million pounds under the
three-tier structure. The two-tier structure would also achieve a reduction at the edge of the field
of 95 million pounds of metals under the two-tier structure and 103 million pounds of metals
under the three-tier structure. Option 2 would also achieve reductions in the numbers of pathogen
colonies which reach the edge of the field, under the two-tier structure the reduction is estimated
to be 125 billion cfu of fecal coliform and 244 billion cfu of fecal streptococcus, the three-tier
structure would achieve additional reductions of 21 billion cfu fecal coliforms and 26 billion cfu
of fecal streptococcus.
As discussed hi Chapter 8, compliance costs for manure transfer assessed to the CAFO include
hauling costs and record keeping. If the recipient is land applying the manure, the recipient is
most likely a crop farmer, and the recipient is assumed to already have a nutrient management
plan that considers typical yields and crop requirements. The recipient is also assumed to apply
manure and wastes on a nitrogen basis, so the application costs are offset by the costs for
commercial fertilizer purchase and application. EPA assumes the recipient may need to sample
soils for phosphorus, and costs for sampling identically to the CAFO, i.e. every three years. EPA
has not accounted for costs that would result from limiting the amount or way recipients are
currently using manure.
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EPA is considering requiring training for persons that will apply manure. There are some slates
which have these requirements. Proper application is critical to controlling pollutant discharges
from crop fields. Some states have established mandatory training for persons that apply manure.
EPA will consult with USDA on the possibility of establishing a national training program for
manure applicators.
10.23 Proposed Basis for BPT Limitations.
EPA is not proposing to establish BPT requirements for the beef, dairy, swine, veal and poultry
subcategories on the basis of Option 1, because it does not represent the best practicable control
technology. In areas that have high to very high phosphorus build up in the soils, Option 1 would
not require that manure application be restricted or eliminated. Thus, the potential for
phosphorus to be discharged from land owned or controlled by the CAFOs would not be
controlled by Option 1. Consequently Option 1 would not adequately control discharges of
phosphorus from these areas. Option 2 would reduce the discharge of phosphorus in field runoff
by restricting the amount of phosphorus that may be applied to the amount that is appropriate for
agricultural purposes or prohibiting the application of manure when phosphorus concentrations
in the soil are very high and additional phosphorus is not needed to meet crop requirements.
EPA's cost estimates assume that a percentage of operations will have to apply manure to crop
land on a phosphorus basis dependent on the region and information available in the USDA's
ARS publication entitled "Agricultural Phosphorus and Eutrophication" (ARS-149). This is
discussed in more detail in Chapter 11.
EPA is proposing to establish BPT limitations for the beef, dairy, swine, veal and poultry
subcategories on the basis of Option 2. EPA's decision to base BPT limitations on Option 2
treatment reflects consideration of the total cost of application of technology in relation to the
effluent reduction benefits to be achieved from such application. Option 2 is expected to cost
$549 million under the two-tier structure and achieve a reduction of pollutants reaching surface
waters over baseline (current) practices 624 million pounds of nutrient and metals for a total cost
to pound ratio of $0.88. The three-tier structure is estimated to cost $583 and achieve a reduction
of 703 million pounds of pollutants for a total cost to pounds removed ratio of $0.82.
The Option 2 technology is one that is readily applicable to all CAFOs. The production area
requirements represent the level of control achieved by the majority of CAFOs in the beef, dairy,
swine, poultry and veal subcategories. USDA and the American Society of Agricultural
Engineers cite the 25-year, 24-hour storm as the standard to which storage structures should
comply. This has been'the standard for many years, and most existing lagoons and other open
liquid containment structures are built to this standard. As described above, the land application
requirements associated with Option 2 are believed to represent proper agricultural practice and
to ensure that CAFO manure is applied to meet the requirements of the crops grown and not
exceed the ability of the soil-and crop to absorb nutrients.
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EPA believes any of the three methods for determining when manure should be applied on a
phosphorus basis would represent BPT. Each method has distinct advantages which depending
on the circumstances, could make one method preferred over another. There has been
considerable work done in this area within the past few years and this work is continuing EPA
believes that this proposed BPT approach provides adequate flexibility to allow states to develop
an approach that works best for the soils and crops being grown within then: state.
CAFOs must also develop and implement a PNP that establishes the appropriate manure
application rate. EPA believes the land application rates established in accordance with one of
the three methods described in today's proposed regulation, along with the prohibition of manure
application within 100 feet of surface water, will ensure manure and wastewater are applied in a
manner consistent with proper agricultural use. For a detailed discussion of how a PNP is
expected to be developed refer to the Draft Guidance Manual for PNPs.
EPA believes that state sampling and analytical protocols are effective; however, soil phosphorus
levels can vary depending on how the soil samples are collected. For example, a CAFO that
surface-applies manure will deposit phosphorus in the surface layer of the soil and should collect
soil samples from the top layer of soil. If this CAFO collects soil samples to a depth of several
niches the analysis may understate the phosphorus build-up near the soil surface. Thus EPA may
evaluate the need to establish specific soil sampling protocols.
10.2.4 Best Control Technology for Conventional Pollutants (BCT)
In evaluating possible BCT standards, EPA first considered whether there are any candidate
technologies (i.e., technology options); that are technologically feasible and achieve greater
conventional pollutant reductions than the proposed BPT technologies. (Conventional pollutants
are defined in the Clean Water Act as including: Total Suspended Solids (TSS), Biochemical
Oxygen Demand (BOD), pH, oil and grease and fecal coliform.) EPA considered the same BAT
technology options described below and their effectiveness at reducing conventional pollutants
EPA's analysis of pollutant reductions has focused primarily on the control of nutrients, nitrogen
and phosphorus. However, the Agency has also analyzed what the technology options can
achieve with respect to sediments (or TSS), metals, and pathogens. Although livestock waste
also contains BOD, EPA did not analyze the loadings or loadings reductions associated with the
technology options for BOD. Thus, the only conventional pollutant considered in the BCT
analysis is TSS. EPA identified no technology option that achieves greater TSS removals than
the proposed BPT technologies see Chapter 12. EPA does not believe that these technology
options would substantially reduce BOD loads. There are therefore no candidate technologies for
more stringent BCT limits. If EPA had identified technologies that achieve greater TSS
reductions than the proposed BPT, EPA would have performed the two part BCT cost test. (See
51 FR 24974 for a description of the methodology EPA employs when setting BCT standards.)
EPA is proposing to establish BCT limits for conventional pollutants equivalent to the proposed
BPT limits.
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10.2.5. Best Available Technology Economically Achievable (BAT)
EPA is considering six technology options to control discharges from CAFOs in the beef, veal
and poultry subcategories, and seven technology options for the dairy and hog subcategories. All
of the technology options include restrictions on land application of manure, best management
practices (BMPs), inspections and record keeping for the animal confinement areas, and
wastewater storage or treatment structures. The following table summarizes the requirements for
each of the seven technology options. Note that a given technology option may include a •
combination of technologies
Table 10-1. Requirements Considered in the Technology Options
Zero Discharge w/
overflow when a 25-24
Design Standard is met
Depth markers for lagoons
Annual Manure Testing
N-basedPNP
100' LA setback
P-basedPNP (where
necessary)
Soil Test - every 3yrs.
Zero discharge without any
allowance for overflow
Hydrologjc Link
Assessment & Zero
Discharge to Groundwater
beneath Production Area
Ambient Surface Water
Sampling (N.P.TSS)
Anaerobic Digestion
w/power generation
Frozen/snow
covered/saturated
application prohibitions
Option!
X
X
X
X
X
Option 2
X
,'
X
X
X
X
X
Options
X
X
X
X
X
X
X
Option 4v
X
X
X
X
X
X
X
X
Options
Cattle &
Dairy
Cattle &
Dairy
X
X
X
X
Swine &
Poultry
Swine
OptionS
X
X
X
X -
X
Swine &
Dairy
Option.'?,.:
„
X
X ...
X
X
X
-
X
X = All Subcategories
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Option 1. This option is equivalent to Option 1 described under BPT. Option 1 would require'
zero discharge from the production area and that liquid storage be designed, constructed and
maintained to handle all process wastewater and storm water runoff from the 25-year, 24-hour
storm event. In addition, Option 1 requires management practices to ensure that the production
area (which includes manure and wastewater storage) is being adequately maintained.
Option 1 also would establish a requirement to develop a PNP which establishes the proper land
application rate for manure and wastewater to meet the nitrogen requirements for the crops being
grown by the CAFO and require a 100 foot setback from surface water, sinkholes, tile drain inlets
and agricultural drainage wells.
Option 2. This option is equivalent to Option 2 described under BPT (See section 10.2.2 of this
Chapter). Option 2 includes all of the requirements established under Option 1. However
Option 2 would further restrict the amount of manure that can be applied to crop land owned or
controlled by the CAFO. The CAFO would be required to apply manure and wastewater at the
appropriate rate taking into account the nutrient requirements of the crop and soil conditions.
Specifically, Option 2 would require that manure be applied at crop removal rate for phosphorus
if soil conditions warrant and, if soils have a very high level phosphorus build-up, no manure or
wastewater could be applied to the crop land owned or controlled by the CAFO.
Option 3. Option 3 includes all the requirements for Option 2 and would require that all
operations perform an assessment to determine whether the ground water beneath the feedlot and
manure storage area has a direct hydrological connection to surface water. EPA has authority to
control discharges to surface water through ground water that has a direct hydrological
connection to surface water. A hydrological connection refers to the interflow and exchange
between surface impoundments and surface water through an underground corridor or ground
water. EPA is relying on the permitting authority to establish the region-specific determination
of what constitutes a direct hydrological link. Option 3 would require all CAFOs to determine
whether they have a direct hydrological connection between the ground water beneath the
production area and surface waters. If a link is established, the facility would have to monitor
ground water up gradient and down gradient of the production area to ensure that they are
achieving zero discharge to ground water.
The literature indicates earthen basins and:clay liners leak, and EPA believes clay is not
sufficient to prevent discharges to groundwater. Clay liners are routinely constructed from
materials obtained locally. These clays vary in their conductivity, and are subject to cracking due
to drying of the sidewalls. Therefore clays do not consistently pose an impermeable barrier.
Similarly, concrete basins may crack and leak over time, particularly in climates with frequent
freeze thaw cycles. EPA has assumed that CAFOs would comply with the zero discharge
requirement by installing liners of synthetic material beneath lagoons and ponds, and impervious
pads below storage of dry manure stockpiles. EPA's costs for liners reflect both a synthetic liner
to provide an impervious layer, and compacted clay to protect the liner and prolong its useful life.
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The clay serves to prevent tearing of the liner by heavy equipment, and also serves to prolong
the life of the synthetic material.
USDA's Natural Resources Inventory (NRT) database for land cover/use which is in close
proximity to animal agricultural facilities (i.e., barns, feedlots, corrals, pens, etc.) were assumed
to be potential sites for animal waste storage structures. Thus NRI subcategories of "Other
Farmland," Farmstead and Ranch Headquarters," and "Other Land in Farms" as well as two other
categories for "Agricultural Production, Facilities" and "Waste, Agricultural Waste" categories
were compiled as potential sites for manure storage structures. Next the NRI soil/hydrologic data
were overlaid onto these potential sites. Soil conditions which were indicative of a potential
hydrologic connection were identified. These conditions included sandy soil textures, shallow
depth to groundwater and karst or karst-like conditions. A percentage of acres which met the
cover/use descriptions and had the characteristics indicative of a potential for a hydrologic
connection was determined for each of the five regions and for the nation as a whole. This
percentage was determined to be 23 percent nationally and this was used to estimate the number
of CAFOs that could incur the costs associated with lining lagoons and monitoring groundwater.
The remaining CAFOs were assumed to incur the cost of obtaining a hydrologic assessment.
CAFOs with a direct hydrologic link would be required to sample the groundwater from the
monitoring wells (located up gradient and down gradient of the production area) at a minimum
frequency of twice per year. These samples are necessary to ensure that pollutants are not being
discharged through groundwater to surface water from the production area. The samples shall be
monitored for nitrate, ammonia, total coliform, fecal coliform, Total Dissolved Solids (TDS) and
total chloride. Differences in concentration of these pollutants between the monitoring well(s)
located up gradient and down gradient of the production area are assumed to represent a
discharge of pollutants and must be prevented. As noted below, coliforms are not necessarily
good indicators of livestock discharges. Also, it is difficult to determine "concentrations" of
coliforms as they are not necessarily evenly distributed in the way chemical contaminants
generally are. EPA requests comment on technical concerns associated with including total and
fecal coliforms in the groundwater monitoring and protection requirements and on ways to
address such concerns.
Option 3 is estimated to cost $746.7 million annually for operations defined as CAFOs under the
two-tier structure. This is an incremental annual cost of $198.1 million over Option 2 costs. For
operations defined as CAFOs under the three-tier structure, Option 3 is estimated to cost $854.1
million annually, which is an incremental annual cost above Option 2 of $271.3 million. Option
3 is estimated to achieve an incremental reduction of pollutants of 5 million pounds of nitrogen
annually. This reflects the pounds lost from nitrogen leaching to groundwater which is directly
connected to surface water.
Option 4. Option 4 includes all the requirements for Option 3 and would require sampling of
surface waters adjacent to feedlots and/or land under control of the feedlot to which manure is
applied. This option would require CAFOs to sample surface water both upstream and
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downstream from the feediot and land application areas following a one half inch rain fall (not to
exceed 12 sample events per year). The samples would be analyzed for concentrations of
nitrogen, phosphorus and total suspended solids (TSS). EPA selected these pollutants because it
believes these pollutants provide an adequate indication of whether a discharge is occurring from
the operation. All sampling results would be reported to the permit authority. Any difference in
concentration between the upstream,and downstream samples would be noted. This monitoring
requirement could provide some indication of discharges from the land application or feediot
areas.
EPA also considered requiring that pathogens and BODS be analyzed in samples collected. EPA
decided that this would not be practical, because sampling under Option 4 is linked to storm
events which limits the ability to plan in advance for analysis of the samples and making
arrangements for shipping samples to laboratories. Fecal coliform and BOD samples all have
very short holding times before they need to be analyzed. Most CAFOs are located in rural areas
with limited access to overnight shipping services and are probably not near laboratories that can
analyze for these pollutants. Further, fecal coliform and similar analytes that are typically used as
indicators in municipal wastewater are not necessarily good indicators of livestock discharges. If
CAFOs were required to monitor for pathogens which could indicate discharges of manure or
CAFO wastewater, it would be better to require monitoring for fecal enterococci, or even specific
pathogens such as salmonella, Giardia, and Cryptosporidium. However, the cost for analyzing
these parameters is very high and the holding times for these parameters are also very short.
Furthermore, EPA determined pathogen analyses are also inappropriate because the pathogens in
manure are found in areas without animal agriculture. For example Enterobacter, Klebsiella,
Bacillus cereus, Clostridium, and Listeria are all naturally occurring soil and plant
microorganisms' and are found in soils that have never received manure. Pathogens may also be
deposited onto land from wildlife. Thus, EPA concluded that requiring analysis for these
pollutants was unpractical at best and potentially very expensive.
EPA estimated the annual cost of Option 4 to be $903.9 million under the two-tier structure
which is $154.2 million incremental to Option 3 . Under the three-tier structure the estimated
annual cost of Option 4 is $ 1.088 billion which is an incremental annual cost of $234.1 million.
The monitoring requirements associated with Option 4 do not directly reduce the pollutants
discharged from CAFOs thus no incremental pollutants reductions were estimated. There could
be some pollutant reductions associated with increased vigilance associated with the monitoring,
however it is not possible to quantify this reduction.
Option 5. Option 5 includes the requirements established by Option 2 and would establish a zero
discharge requirement from the production area that does not allow for an overflow under any
circumstances. By keeping precipitation from contacting with the animals, raw materials, waste
handling and storage areas, CAFOs could operate the confinement areas and meet zero discharge
regardless of rainfall events. Option 5 includes the same land application requirements as Option
2, which would restrict the rate of manure and wastewater application to a crop removal rate for
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phosphorus where necessary depending on the specific soil conditions at the CAFO.
Additionally, as in Option 2, application of manure and wastewater would be prohibited within
100 feet of surface water.
EPA considered Option 5 for the poultry, veal and hog subcategories, where it is common to
keep the animals in total confinement, feed is generally maintained in enclosed hoppers and the
manure and wastewater storage can be handled so as to prevent it from contacting storm water.
EPA considered a number of ways a facility might meet the requirements of no discharge and no
overflow. In estimating the costs associated with Option 5, EPA compared the total costs and
selected the least expensive technology for a given farm size, geographic region, and manure
management system. Costs also depend on whether the facility's PNP indicates land application
must be based on nitrogen or phosphorus, and how many acres the facility controls. The
technologies described below were used singularly or in combination to meet the requirements of
Option 5.
Many facilities can achieve Option 5 by covering open manure and storage areas, and by
constructing or modifying berms and diversions to control the flow of precipitation. EPA costed
broiler and turkey operations for storage sheds sufficient to contain six months of storage. Some
poultry facilities, particularly turkey facilities, compost used litter in the storage sheds, allowing
recycle and reuse of the litter. EPA costed swine, veal, and poultry facilities which use lagoons
or liquid impoundments for impoundment covers.
EPA believes that operations which have excess manure nutrients and use flush systems to move
manure out of the confinement buildings will have an incentive to construct a second lagoon cell.
A second storage or treatment cell should accomplish more decomposition of the waste and will
allow flush water to be recycled out of the second cell or lagoon, thus reducing the addition of
fresh water to the system. Reducing the total volume of stored waste reduces the risk of a
catastrophic failure of the storage structure. In the absence of large volumes of water, facilities
with an excess of manure nutrients will be able to transfer the excess manure off-site more
economically due to a lower volume of waste needing to be hauled. Water reduction also results
hi a more concentrated product which would have a higher value as a fertilizer.
Covered systems substantially reduce ah" emissions, and help maintain the nutrient value of the
manure. Covered systems also may benefit facilities by reducing odors emanating from open
storage. This option also creates a strong incentive for facilities to utilize covered lagoon
digesters or multistage covered systems for treatment. The use of covers will allow smaller and
more stable liquid impoundments to be constructed. Finally, the use of covered impoundments
encourages treatment and minimal holding times, resulting in pathogen die-off and reduction of
BOD and volatile solids.
Other technologies can be effectively used at some facilities, such as conversion of flush systems
to scrape systems, or by retrofit of slatted floor housing to V-shaped under house pits that
facilitate solid liquid separation. Solids can be stored or composted in covered sheds, while the
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urine can be stored in small liquid impoundments. Solid-liquid separation is discussed in •
Chapters.
In the event the facility has insufficient land to handle all nutrients generated, EPA evaluated
additional nutrient management strategies. First, the manure could pass through solid separation,
resulting in a smaller volume of more concentrated nutrients that is more effectively transported '
offsite. Second, land application could be based on the uppermost portion of a covered lagoon
containing a more dilute concentration of nutrients. Data indicates much of the phosphorus
accumulates in the bottom sludge, which is periodically removed and could be transported offsite
for proper land application. Though many facilities report sludge removal of a properly
operating lagoon may occur as infrequently as every 20 years, EPA assumed facilities would
pump out the phosphorus and metals enriched sludge every three years. This is consistent with
the ANSI/ASAE standards for anaerobic treatment lagoons (EP403.3 JUL99) that indicates
periodic sludge removal and liquid draw down is necessary to maintain the treatment volume of
the lagoon. Third, swine and poultry farms can implement a variety of feeding strategies, as
discussed under Option 2 (see Section VH.C.3). Feed management including phytase, multistage
diets, split sex feeding, and precision feeding have been shown to reduce phosphorus content hi
the manure by up to 50%. This results in less excess nutrients to be transported offsite, and
allows for more manure to be land applied at the CAFO.
EPA is aware of a small number of swine facilities that are potentially CAFOs and use either
open lots or some type of building with outside access to confine the animals. EPA data indicate
these types of operations are generally smaller operations that would need to implement different
technologies than those described above. CAFOs that provide outdoor access for the animals.
need to capture contaminated storm water that falls on these open areas. Open hog lots would
find it difficult to comply with a requirement that does not allow for overflows in the event of a
large storm. EPA costed these facilities to replace the open lots with hoop houses to confine the
animals and storage sheds to contain the manure. Hoop structures are naturally ventilated
structures with short wooden or concrete sidewalls and a canvas, synthetic, or reflective roof
supported by tubes or trusses. The floor of the house is covered with straw or similar bedding
materials. The manure and bedding is periodicallyremoved and stored. The drier nature of the
manure lends to treatment such as composting as well as demonstrating reduced hauling costs as
compared to liquid manure handling systems.
EPA considered a variation to Option 5 that would require CAFOs to use dry or drier manure
handling practices. This variation assumed conversion to a completely dry manure handling
system for hogs and laying hens using liquid manure handling systems. In addition to the
advantages of reduced water use described above, a completely dry system is more likely to
minimize leaching to ground water and, where directly connected hydrologically to surface
water, will also reduce loads to surface waters. Tor the beef and dairy subcategories EPA
assumes that the liquid stream would be treated to remove the solids and the solids would be
composted. It is not practical to assume existing beef and dairy operations can avoid the
generation of liquid waste because operations in both subcategories tend to have animals in open
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areas exposed to precipitation resulting in a contaminated storm water that must be captured.
Also dairies generate a liquid waste stream from the washing of the milking parlor.
Option 5 is estimated to cost $1,515.9 million annually under the two-tier structure and $1,632.9
annually under the three-tier structure. The amount of manure and application methods under
Option 5 are no different than required under Options 2. Therefore, the quantify of pollutants
which reach the edge-of-field under Option 5 is not expected to be any less than under Option 5.
Options 5 will reduce pollutants discharged from the production area during chronic or
catastrophic storms that exceed the design standard, however, EPA has not quantified this
amount
Option 6. Option 6 includes the requirements of Option 2 and requires that large hog and dairy
operations (hog operations and dairies with 2,000 AU) would install and implement anaerobic
digestion to treat their manure and use the captured methane gas for energy or heat generation.
With proper management, such a system can be used to generate additional on-farm revenue.
The enclosed system will reduce air emissions, especially odor and hydrogen sulfide, and
potentially reduces nitrogen losses from ammonia volatilization. The treated effluent will also
have less odor and should be more transportable relative to undigested manure, making offsite
transfer of manure more economical. Anaerobic digestion under thermophilic or heated
conditions would achieve additional pathogen reductions. Digester technology is described in
Chapters, see 8.2.3.1.
Option 6 is estimated to cost $621.6 million annually under the two-tier structure and $736.9
million annually under the three-tier structure., As described under Option 5, Option 6 does.not
affect the amount of manure or the chemical characteristics of the manure applied to the land,
thus the pollutant loads expected to reach the edge of the field are the same as under Option 2.
There could be some reduction from fewer discharges at the production area, but the requirement
to use a anaerobic digester does not eliminate the need for storage which is not assumed to be
covered under Option 6, thus the requirement would allow for an overflow.
Option 7. Option 7 includes the requirements of Option 2 and would prohibit manure application
to frozen, snow covered or saturated ground. This prohibition requires that CAFOs have
adequate storage to hold manure for the period of time during which the ground is.frozen or
saturated. The necessary period of storage ranges from 45 to 270 days depending on the region.
In practice, this may result in some facilities needing storage to hold manure and wastes for 12
months. EPA assumed storage would be needed to contain manure and precipitation generated
for the entire period between the first frost in the fall until the last frost in the spring rounded to
the nearest 45 day interval. In northern states this period can be as long as 270 days. It is likely
that there could be opportunities to apply manure during this period, depending on how the
restrictions on application are defined, thus EPA's cost estimates for this option should represent
a worst-case cost.
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EPA estimates the cost for Option 7 to be $671,3 million annually under the two-tier structure,
and $781.9 million annually under the three-tier structure. EPA did not estimate pollutant
reductions from this technology option because the Agency has limited information on how
frequently manure is being applied by existing CAFOs, and the runoff associated with
application on frozen, snow-covered or saturated ground is dependent on regional factors such as
rainfall patterns and site-specific factors sucLas topography.
10.2.6 Proposed Basis for BAT
10.2.6.1 BAT Requirements for the Beef and Dairy Subcategories
EPA is proposing to establish BAT requirements for both the beef and dairy subcategories based
on the same technology option. The beef subcategory includes stand-alone heifer operations and
applies to all confined cattle operations except for operations that confine mature dairy cattle or
veal. Under the two-tier structure, the BAT requirements would apply to any beef operation with
500 head of cattle or more. Under the three-tier structure, the BAT requirements for beef would
apply to any operation with more than 1,000 head of cattle and any operation with 300 to 1,000
head which meets the conditions that define the operation as a CAFO.
EPA proposes to establish BAT requirements for dairy operations which meet the following
definitions: under the two-tier structure, all dairy with 350 head of mature dairy cows or more
would be subject to the proposed BAT requirements. Under the three-tier approach any dairy
with more than 700 head of mature dairy cows or 250 to 700 head of mature dairy cows which
meets the conditions that define the operation as a CAFO (see Chapter 9) would be subject to
today's proposed BAT requirements.
EPA proposes to establish BAT requirements for the beef and dairy subcategories based on
Option 3. BAT would require all beef and dairy CAFOs to monitor the ground water beneath the
production area by drilling wells up gradient and down gradient to measure for a plume of
pollutants discharged to ground water at the production area. A beef or dairy CAFO can avoid
this ground water monitoring by demonstrating, to the permit writer's satisfaction, that it does
not have a direct hydrological connection between the ground water beneath the production area
and surface waters.
EPA proposes to require CAFOs in the beef and dairy subcategories to monitor their ground
water unless they determine that the production area is not located above ground water which has
a direct hydrological connection to surface water. CAFOs would have to monitor for ammonia,
nitrate, fecal coliform, total coliform, total chlorides and TDS. EPA selected these pollutants
because they may be indicators of livestock waste and are pollutants of concern to ground water
sources. If the down gradient concentrations are higher than the up gradient concentration this
indicates a discharge which must be controlled. For operations have a direct hydrologic
connection, EPA based the BAT zero discharge requirement on the installation of liners in liquid
storage structures such as lagoons and storm water retention ponds and concrete pads for the
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storage of dry manure stockpile's. If the CAFO is determined to have a direct hydrologic
connection between the groundwater beneath the production area and surface wafer, the CAFO
would need to line lagoons to prevent leaching and construct concrete pads on which to store .
manure stockpiles. EPA's cost estimates assumed operations would construct new liquid storage
structures with both a synthetic and clay liner.
Beef and dairy CAFOs must also develop and implement a PNP that is based on application of
manure and wastewater to crop land either at a crop removal rate for phosphorus where soil
conditions require it, or otherwise on the nitrogen requirements of the crop. EPA believes the
land application rates established in accordance with one of the three methods described hi
today's proposed regulation, along with the prohibition of manure application within 100 feet of
that surface water will ensure manure and wastewater are applied in a manner consistent with
proper agricultural use. See the draft guidance entitled "Managing Manure Nutrients at
Concentrated Animal Feeding Operations" for a detailed discussion of how a PNP is developed.
EPA believes that technology option 3 is economically achievable and represents the best
available technology for the beef and dairy subcategories, and is therefore proposing this option
as BAT for these subcategories. The incremental annual cost of Option 3 relative to Option 2 for
these subcategories is $170 million pre-tax under the two-tier structure, and $1205 million pre-
tax under the three tier structure. EPA estimated annual ground water protection benefits from
the proposed requirements of $70-80 million. EPA estimates Option 3 for the beef and daily
subcategories will reduce loadings to surface waters from hydrologLcally connected ground water
by 3 million pounds of nitrogen. To determine economic achievability, EPA analyzed how many
facilities would experience financial stress severe enough to make them vulnerable to closure
under each regulatory option. As explained in more detail in the Economic Analysis, the number
of facilities experiencing stress may indicate that an option might not be economically
achievable, subject to additional considerations. Under Option 2, no facilities in either the beef
or dairy sectors were found to experience stress, while under Option 3, the analysis projects 10
beef and 329 dairy CAFOs would experience stress under the two-tier structure, and 40 beef and
610 dairy CAFOs would experience stress under the three-tier structure. Of these, EPA has
determined that 40 beef operations are considered small businesses based on size standards
established by the Small Business Administration. This analysis assumes that 76% of affected
operations would be able to demonstrate that then- ground water does not have a hydrological
connection to surface water and would therefore not be subject to the proposed requirements.
EPA projects the cost of making this demonstration to the average CAFO would be $3,000.
EPA is not proposing to establish BAT requirements for the beef and dairy subcategories on the
basis of Option 4 due to the additional cost associated with ambient stream monitoring and
because the addition of in-stream monitoring does not by itself achieve any better controls on the
discharges from CAFOs as compared to the other options. In-stream monitoring could be an
indicator of discharges occurring from the CAFO; however, it is equally likely that in stream
monitoring will measure discharges that may be occurring from adjacent non-CAFO agricultural
sources. Through the use of commercial fertilizers these non-CAFO sources would likely be
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contributing the same pollutants being analyzed under Option 4. EPA has not identified a better
indicator parameter which would isolate constituents from CAFO manure and wastewater from
other possible sources contributing pollutants to a stream. Livestock specific pathogen analysis
could be an indicator if adjacent operations do not also have livestock or are not using manure or
biosolids as fertilizer sources. However, as described earlier, EPA has concerns about the ability
of C AFOs to collect and analyze samples for these pollutants because of the holding time
constraints associated with the analytical methods for these parameters. Accordingly, EPA does
not believe that specifying these additional in-stream monitoring BMP requirements would be
appropriate; and would not be useful in ensuring compliance with the .Clean Water Act.
Moreover, in-stream monitoring would be a very costly requirement for CAFOs to comply with.
EPA is not proposing to establish BAT requirements for the beef and dairy subcategories on the
basis of Option 5. Option 5 would require zero discharge with no overflow from the production
area. Most beef feedlots are open lots which have large areas from which storm water must be
collected; thus, it is not possible to assume that the operation can design a storm water
impoundment that will never experience an overflow even under the most extreme storm. Stand
alone heifer operations (other than those that are pasture-based) are configured and operated hi a
manner very similar to beef feedlots. Unlike the hog, veal and poultry subcategories, EPA is not
aware of many large beef operations that keep all cattle confined under roof at all times.
Dairies also frequently keep animals in open areas for some period of time, whether it is simply
the pathway from the bam to the milk house or an open exercise lot. Storm water from these
open areas must be collected in addition to any storm water that contacts food or silage. As is the
case for beef feedlots, the runoff volume from the exposed areas is a function of the size of the
area where the cattle are maintained, and the amount of precipitation. Since the CAFO operator
cannot control the amount of precipitation, there always remains the possibility that an extreme
storm event can produce enough rainfall that the resulting runoff would exceed the capacity of
the lagoon.
EPA did consider a new source option for new dairies that would enforce total confinement of all
cattle at the dairy. The new source option as analyzed, poses a barrier to entry for new sources,
therefore, EPA assumes that this option if applied to existing sources would be economically
unachievable. EPA plans to continue evaluating this option and will consider other technology
approaches that could be applied. EPA has also evaluated a variation of Option 5 that would
apply to existing beef and dairy operations and would require the use of technologies which
achieve a less wet manure. These technologies include solid-liquid separation and composting
the solids. EPA is not proposing to establish BAT on the use of these technologies, but does
believe these technologies may result in cost savings at some operations. Additionally,
composting will achieve pathogen reductions. As described in Chapter 7, EPA is continuing to
examine pathogen controls and may promulgate requirements on the discharge of pathogens. If
EPA set limitations on pathogens, composting technology would likely become a basis for
achieving BAT limits.
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For any operation that has inadequate crop land on which to apply its manure and wastewater,
solid-liquid separation and composting could benefit the CAFO, as these technologies will make
the manure more transportable. Drier manure is easier to transport; and therefore, EPA believes
solid liquid separation and composting will be used in some situations to reduce the
transportation cost of excess manure that has been treated to concentrate and compost the solids.
In addition, composting is a value-added process that improves the physical characteristics (e.g.,
reduces odor and creates a more homogenous product) of the manure. It can also make the
manure a more marketable product. As a result, a CAFO with excess manure may find it easier
to give away, or even sell, its excess manure. EPA encourages all CAFOs to consider
technologies that will reduce the volume of manure requiring storage and make the manure easier
to transport.
Option 6, which, requires anaerobic digestion treatment with methane capture, was not considered
for the beef subcategory, but was considered for the dairy subcategory for treatment of liquid
manure. Anaerobic digestion can only be applied to liquid waste. As described previously in
Chapter 4, beef feedlots maintain a dry manure, yet they capture storm water runoff from the dry
lot and manure stockpile. The storm water runoff is generally too dilute to apply digestion
technology.
Most dairies, however, handle manure as a liquid or slurry which is suited to treatment through
anaerobic digestion. EPA concluded that application of anaerobic digesters at dairies will not
necessarily lead to significant reductions in the pollutants discharged to surface waters from
CAFOs. An anaerobic digester does not eliminate the need for liquid impoundments to store
dairy parlor water and bam flush water and to capture storm water runoff from the open, areas at
the dairy. Neither do digesters reduce the nutrients nitrogen or phosphorus. Thus, basing BAT
on digester technology would not change the performance standard that a production area at a
CAFO would achieve and would not reduce or eliminate the need for proper land application of
manure. Digesters were considered because they achieve some degree of waste stabilization and
more importantly they capture air emissions generated during manure storage. The emission of
ammonia from manure storage structures is a potentially significant contributor of nitrogen to
surface waters. Covered anaerobic digesters will prevent these emissions while the waste is in
the digester, but the digester does not convert the ammonia into another form of nitrogen, such as
nitrate, which is not as volatile. Thus as soon as the manure is exposed to air the ammonia will
be lost. Operations may consider additional management strategies for land application such as
incorporation in order to maintain the nitrogen value as fertilizer and to reduce emissions.
As mentioned above, the application of ambient temperature or mesophilic anaerobic digesters
would not change the performance standard that a CAFO would achieve. Thermophilic digestion
or pasteurization processes which apply heat to the waste will reduce pathogens. As described in
Chapter 7 EPA is still evaluating effective controls for pathogens and thermophilic process is one
of the controls EPA will continue to evaluate. At present thermophilic anaerobic digestion is
only used for centralized treatment of animal waste in Europe. Thermophilic aerobic treatment is
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practiced on municipal waste. This technology has also been evaluated for transferability to
CAFOs. These technologies, their advantages and limitations are discussed in Chapter 8.
EPA is not proposing to base BAT requirements on Option 7 for the beef and dairy
subcategories. Option 7 would prohibit manure application on saturated, snow covered or frozen
ground. Pollutant runoff associated with application of manure or wastewater to saturated, snow
covered or frozen ground is a site specific consideration, and depends on a number of site
specific variables, including distance to surface water and slope of the land. EPA believes that
establishing a national standard that prohibits manure or wastewater application is inappropriate
because of the site specific nature of these requirements and the regional variability across the
nation.
Requirements for the beef and dairy subcategories would still allow for an overflow in the event
of a chronic or catastrophic storm that exceeds the 25-year, 24-hour storm. EPA believes this
standard reflects the best available technology. Under the proposed revisions to Part 122,
permits will require that any discharge from the feedlot or confinement area be reported to the
permitting authority within 24 hours of the discharge event. The CAFO operator must also
report the amount of rainfall and the approximate duration of the storm event.
10.2.6.2 BAT Requirements for the Swine, Veal and Poultry Subcategories
EPA is proposing to establish BAT requirements for the swine, veal and poultry subcategories
based on Option 5. Option 5 requires zero discharge of manure and process wastewater and
provides no overflow allowance for manure and wastewater storage. Land application
requirements for these operations would be the same as the requirements under Option 2.
EPA is proposing Option 5 because swine, veal and poultry operations can house the animals
under roof and feed is also not exposed to the weather. Thus, there is no opportunity for storm
water contamination. Broiler and turkey operations generate a dry manure which can be kept
covered either under a shed or with tarps. Laying hens with dry manure handling usually store
manure below the birds' cages and inside the confinement building. Veal and poultry operations
confine the animals under roof, thus there are no open animal confinement areas to generate
contaminated storm water. Those operations with liquid manure storage can comply with the
restrictions proposed under this option by diverting uncontaminated storm water away from the
structure, and covering the lagoons or impoundments.
The technology basis for the poultry BAT requirements at the production area are litter sheds for
broiler and turkey CAFOs, and under house storage for laying hens with dry manure handling
systems. For laying hen CAFOs with liquid manure handling systems, EPA's technology basis is
solid separation and covered storage for the solids and covered lagoons.
Laying hen farms may also have egg wash water from in-line or off-line processing areas.' Only
10% of laying hen operations with fewer than 100,000 birds have on farm egg processing, while
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35% of laying hen operations with more than 100,000 birds have on farm egg processing. The
wash water is often passed through a settling system to remove calcium, then stored in above
ground tanks, below ground tanks, or lagoons. Today's proposal is based on covered storage of
the egg wash water from on-farm processing, to prevent contact with precipitation. The ultimate
disposal of egg wash water is through land application which must be done in accordance with
the land application rates established in the PNP. EPA believes the low nutrient value of egg
wash water is unlikely to cause additional incremental costs to laying hen facilities to comply
with the proposed land application requirements.
EPA assumes large swine operations (e.g., operations with more than 1,250 hogs weighing 55
pounds or greater) operate using total confinement practices. EPA based BAT Option 5 on the
same approach described above of covering liquid manure storage. CAFOs can operate covered
lagoons as anaerobic digesters which is an effective technology for achieving zero discharge and
will provide the added benefits of waste stabilization, odor reduction and control of air emissions
from manure storage structures. Anaerobic digesters also can be operated to generate electricity
which can be used by the CAFO to offset operating costs.
Although Option 5 is the most expensive option for the hog subcategory, EPA believes this
option reflects best available technology economically achievable because it prevents discharges
resulting from liquid manure overflows that occur in open lagoons and ponds. Similarly, the
technology basis of covered treatment lagoons and drier manure storage is believed to reduce the
likelihood of those catastrophic lagoon failures associated with heavy rainfalls. Option 5 also
achieves the greatest level of pollutant reductions from runoff reaching the edge of the field.
Non-water quality environmental impacts include reduced emissions and odor, with a concurrent
increase in nitrogen value of the manure, however as mentioned previously, the ammonia
concentration is not reduced and once the manure is exposed to air the ammonia will volatilize.
Water conservation and recycling practices associated with Option 5 will promote increased
nutrient value of the manure, reduced hauling costs via reduced water content, and less fresh
water use.
One technology basis evaluated for Option 5, solid-liquid separation and storage of the solids,
has the advantage of creating a solid fraction which is more transportable, thus hog CAFOs that
have excess manure can use this technology to reduce the transportation costs.
EPA is aware of three open lot hog operations that have more than 1,250 hogs and there may be a
small number of others, but the predominant practice is to house the animals in roofed buildings
with total confinement. For open lot hog CAFOs, EPA is proposing to base BAT on the
application of hoop structures as described above. Under EPA's proposed three-tier structure,
operations defined as CAFOs in the middle tier that are smaller than 1,250 hogs have a greater
potential for being an open lot type of operation. These operations would also be subject to the
proposed zero discharge requirement, which is based on the application of hoop houses and
covered manure storage.
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Veal operations use liquid manure management and store manure in lagoons. EPA has based
BAT on covered manure and feed storage. The animals are housed in buildings with no outside
access. Thus, by covering feed and waste storage the need to capture contaminated storm water
is avoided.
In evaluating the economic achievability of Option 5 for the swine, veal and poultry
subcategories, EPA evaluated the costs and impacts of this option relative to Option 2. For these
subcategories, the incremental annual cost of Option 5 over Option 2 would be $110 million pre-
tax under the two-tier structure, and $ 140 million pre-tax under the three-tier structure. Almost
all of these incremental costs are projected to be hi the swine sector. EPA projects that there
would be no additional costs under the two-tier structure, and only very small additional costs
under the three-tier structure for the veal and poultry subcategories to move from Option 2 to
Option 5. Under Option 2, EPA estimates 300 swine operations and 150 broiler operations
would experience stress under the two-tier structure, and 300 swine operations and 330 broiler
operations would experience stress under the three-tier structure. Under Option 5 an additional
1,120 swine operations would experience stress under both the two-tier and three-tier structures.
All affected hog operations have more than 1000 AU. None of these affected hog operations are
small businesses based on the Small Business Administration's size standards. There would be
no additional broiler operations experiencing stress under Option 5, and no veal, layer, or turkey
operations are projected to experience stress under either Option 2 or Option 5. EPA did not
analyze the pollutant reductions.of Option 5 relative to Option 2. Under Option 2 operations are
required to be designed, constructed and operated to contain all process generated waste waters,
plus the runoff from a 25-year, 24-hour rainfall event for the location of the point source. Thus,
the benefit of Option 5 over Option 2 would be the value of eliminating discharges during
chronic or .catastrophic rainfall events of a magnitude of the 25-year, 24-hour rainfall event or
greater. Further benefit would be realized as a result of increased flexibility on the timing of
manure application to land. By preventing the rainfall and run-off from mixing with wastewater,
CAFOs would not need to operate such that land application during storm events was necessary.
EPA is not proposing Option 2 for these sectors. As mentioned previously, all of these sectors
maintain then- animals under roof eliminating the need to capture contaminated storm water from
the animal confinement area, hi addition,-most poultry operations generate a dry manure, which
when properly stored, under some type of cover, eliminates any possibility of an overflow in the
event of a large storm.x Therefore EPA believes that Option 5 technology which prevents the
introduction of storm water into manure storage is achievable and represents Best Available
Technology, without redesigning the capacity of existing manure storage units.
EPA is not proposing to base BAT for the swine, poultry and veal subcategories on Option 3,
because EPA believes Option 5 is more protective of the environment. If operators move
towards dry manure handling technologies and practices to comply with Option 5, there should
be less opportunity for ground water contamination and surface water contamination through a
direct hydrological connection. EPA strongly encourages any newly constructed lagoons or
anaerobic digesters to be done in such a manner as to minimize pollutant losses to ground water.
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A treatment lagoon should be lined with clay or synthetic liner or both and solid storage should
be on a concrete pad or a glass-Ikied steel tank as EPA has included in its estimates of BAT
costs. Additionally, Option 5 provides the additional non-water quality benefit of achieving
reductions in air emissions from liquid storage systems. EPA estimates that the cost of
complying with both Option 3 and 5 at existing facilities would be economically unachievable.
EPA believes the proposed technology basis for broilers, turkeys and laying hens with dry
manure management will avoid discharges to ground water since the manure is dry and stored in
such a way as to prevent storm water from reaching it. Without some liquid to provide a
transport mechanism, pollutants cannot move through the soil profile and reach the ground water
and surface water through a direct hydrological connection.
EPA is not proposing to base BAT on Option 4 for the same reasons described above for the beef
and dairy subcategories.
EPA is not proposing to base BAT on Option 6, because EPA believes that the zero discharge
aspect of the selected option will encourage operations to consider and install anaerobic digestion
in situations where it will be cost effective.
As with beef and dairy, EPA is not proposing to base BAT for swine, veal and poultry on Option
7, but believes that permit authorities should establish restrictions as necessary in permits issued
to CAFOs. Swine, veal and poultry operations should take the timing of manure application into
account when developing the PNP. Any areas that could result in pollutant discharge from
application of manure to frozen, snow covered or saturated ground should be identified in the
plan and manure or wastewater should not be applied to those areas when there is a risk of
discharge.
Mixed Animal CAFOs. As described in the preamble of the proposed regulation, EPA is
proposing to drop from the definition of CAFO the mixed animal calculations. Nonetheless,
there are operations that will be CAFO by virtue of having a livestock enterprise which meets the
definition of CAFO. If an operation is defined as a CAFO for one or more livestock enterprises,
then all livestock which is maintained in confinement will be covered under the NPDES permit
requirements. EPA assumes that each distinct livestock sector would be subject to the
appropriate requirements for that sector, however, if the waste or wastewater from two sectors
are commingled then the more stringent requirements would apply to the commingled waste
stream.
PNP Requirements
There are a number of elements that are addressed by both USDA's "Guidance for
Comprehensive Nutrient Management Plans (CNMPs)" and EPA's PNP which would be
required by the effluent guidelines and NPDES proposed rules and is detailed in the guidance
document "Managing Manure Nutrients at Concentrated Animal Feeding Operations." EPA's
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proposed PNP would establish requirements for GAFOs that are consistent with the technical
guidance published by USDA experts, but go beyond that guidance by identifying specific
management practices that must be implemented. What follows is a brief description of what
must be included in a PNP.
General Information. The PNP must have a Cover Sheet which contains the name and location
of the operation, the name and title of the owner or operator and the name and title of the person
who prepared the plan. The date (month, day, year) the plan was developed and amended must
be clearly indicated on the Cover Sheet. The Executive Summary would briefly describe the
operation in terms of herd or flock size, total animal waste produced annually, crop identity for
the full 5 year period including a description of the expected crop rotation and, realistic yield
goal. The Executive Summary must include indication of the field conditions for each field unit
resulting from the phosphorus method used (e.g., phosphorus index), animal waste application
rates, the total number of acres that will receive manure, nutrient content of manure and amount
of manure that will be shipped off-site. It should also identify the manure collection, handling
storage, and treatment practices, for example animals kept on bedding which is stored in a shed
after removal from confinement house, or animals on slatted floors over a shallow pull plug pit
that is drained to an outdoor in-ground slurry storage inpoundment. Finally, the Executive
Summary would have to identify the watershed(s) in which the fields receiving manure are
located or the nearest surface water body. While the General Information section of a PNP
would give a general overview of the CAFO and its nutrient management plan, subsequent
sections would provide further detail.
•Animal Waste Production.* This subsection details types-and quantities of animal waste produced
along with manure nutrient sampling techniques and results. Information would be included on
the maximum number of livestock ever confined and the maximum livestock capacity of the
CAFO, in addition to the annual livestock production. This section would provide an estimate of
the amount of animal waste collected each year. Each different animal waste source should be
sampled annually and tested by an accredited laboratory for nitrogen, phosphorous, potassium,
and pH.
Animal Waste Handling, Collection, Storage, and Treatment. This subsection details best
management practices to protect surface and groundwater from contamination during the
handling, collection, storage, and treatment of animal waste. A review would have to be
conducted of potential water contamination sources from existing animal waste handling
collection, storage, and treatment practices. The capacity needed for storage would be calculated.
Contaminated feedlot runoff would have to be contained and adequately managed. Runoff
diversion structures and animal waste storage structures would have to be visually inspected for
seepage, erosion, vegetation, animal access, reduced freeboard, and functioning rain gauges and
irrigation equipment, on a weekly basis. Deficiencies based on visual inspections would have to
be identified and corrected within a reasonable time frame. Depth markers would have to be
permanently installed in all open lagoons, ponds, and tanks. Lagoons, ponds, and tanks at beef
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and daiiy CAFOs would have to be maintained to retain capacity for the 25-year, 24-hour storm
event. Dead animals, required to be kept out of lagoons, would have to be properly handled and
disposed of in a timely manner. Finally, an emergency response plan for animal waste spills and
releases would have to be developed.
Land Application Sites. This subsection details field identification and soil sampling.
County(ies) and watershed code(s) where feedlot and land receiving animal waste applications
are located would be identified. Total acres of operation under the control of the CAFO (owned
and rented) and total acres where animal waste will be applied would be included. A detailed
farm map or aerial photo, to be included, would have to indicate: location and boundaries of the
operation, individual field boundaries, field identification and acreage, soil types and slopes, and
the location of nearby surface waters and other environmentally sensitive areas (e.g., wetlands,
sinkholes, agricultural drainage wells, and aboveground tile drain intakes) where animal waste .
application is restricted.
Separate soil sampling, using an approved method, would have to be conducted every 3 years on
each field receiving animal waste. The samples shall be analyzed at an accredited laboratory for
total phosphorous. Finally, the phosphorous site, rating for each field would have .to be recorded
according to the selected assessment tool.
Land Application. This subsection details crop production and animal waste application to crop
production areas. Details of crop production would have to include: identification of all planned
crops, expected crop yields and the basis for yield estimates, crop planting and harvesting dates,
crop residue management practices, and nutrient requirements of the crops to be grown.
Calculations used to develop the application rate, including nitrogen credits from legume crops,
available nutrients from past animal waste applications, and nutrient credits from other fertilizer
and/or biosolids applications would have to be included.
Animal waste application rates cannot exceed nitrogen requirements of the crops. However,
animal waste application rates would be limited to the agronomic requirements for phosphorous
if the soil phosphorous tests are rated "high", the soil phosphorous tests are equal to 3/4, but not
greater than twice the soil phosphorous threshold value, or the Phosphorous Index rating is
"high." Finally, animal waste could not be applied to land if the soil phosphorous tests are rated
"very high", the soil phosphorous tests are greater than twice the soil phosphorous threshold
value, or the Phosphorous Index rating is 'Very high." In some cases, operators may choose to
further restrict application rates to account for other limiting factors such as salinity or pH.
Animal wastes cannot be applied to wetlands or surface waters, within 100 feet of a sinkhole, or
within 100 feet of water sources such as rivers, streams, lakes, ponds, and intakes to agricultural
drainage systems (e.g., aboveground tile drain intakes, agricultural drainage wells, pipe outlet
terraces). EPA requests comment on how serious would be the limitations imposed by these
requirements. Manure spreader and irrigation equipment would have to be calibrated at a
minimum once each year, but preferably before each application period. Finally, the date of
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animal waste application and calibration application equipment, and rainfall amounts 24-hours
before and after application would be recorded.
Other Uses/Off-Site Transfer. The final required subsection for a PNP details any alternative
uses and off-site transport of animal wastes. If used, a complete description of alternative uses of
animal waste would have to be .included. If animal wastes are transported off-site the following
would have to be recorded: date (day, month, year), quantity, and name and location of the
recipient of the annual waste.
Voluntary Measures. Many voluntary best management practices can be included within various
subsections of a PNP. These voluntary best management plans are referenced in EPA's guidance
document for PNP "Managing Manure Nutrients at Concentrated Animal Feeding Operations."
Annual Review and Revision. While a PNP is required to be renewed every 5 years (coinciding
with NPDES permitting), an annual review of the PNP would have to occur and the PNP would
be revised or amended as necessary.
The most likely factor which would necessitate an amendment or revision to a PNP is a change in
the number of animals at the CAFO. A substantial increase in animal numbers (for example an
increase of greater than 20%) would significantly increase the volume of manure and total
nitrogen and phosphorous produced on the CAFO. Because of this, the CAFO will need to re-
evaluate animal waste storage facilities to ensure adequate capacity, and may need to re-examine
the land application sites and rates.
A second reason which would require an amendment or revision to a PNP is a change in the
cropping program which would significantly alter land application of animal waste. Changes in
crop rotation or crop acreage could significantly alter land application rates for fields receiving
animal waste. Also the elimination or addition of fields receiving animal waste application
would require a change hi the PNP.
Changes in animal waste collection, storage facilities, treatment, or land application method
would require an amendment or revision to a PNP. For example, the addition of a solid-liquid
separator would change the nutrient content of the various animal waste fractions and the method
of land application thereby necessitating a revision in a PNP. Changing from surface applicatL
to soil injection would alter ammonia volatilization subsequently altering animal waste nutrient
composition requiring a revision of land application rates.
When CAFOs Must Have PNPs. EPA proposes to allow two groups of CAFOs up to 90 days to
obtainaPNP: y
1. existing CAFOs which are being" covered by a NPDES permit for the first time; or
2. existing CAFOs that are already covered under an existing permit which is
reissued within 3 years from the date of promulgation of these regulations.
.on
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EPA proposes that all other existing CAFOs must have a PNP at the time permits are issued or
renewed.
10.2.7 New Source Performance Standards
For purposes of applying the new source performance standards (NSPS) being proposed today, a
source would be a new source if it commences construction after the effective date of the
for&coming final rule. Each source that meets this definition would be required to achieve any
newly promulgated NSPS upon commencing operation of the CAFO.
EPA proposes to consider an operation as a new source if any of the following three criteria
apply. The definition of new source being proposed for Part 412 states three criteria that
determine whether a source is a "new source."
First, a facility would be a new source if it is constructed at a site at which no other source is
located. These new sources have the advantage of not having to retrofit the operation to comply
with BAT requirements, and thus can design to comply with more stringent and protective
requirements.
The second criterion for defining a new source would be where new construction at the facility
"replaces the housing, waste handling system, production process, or production equipment that
causes the discharge or potential to discharge pollutants at an existing source." Confinement
housing and barns are periodically replaced, allowing the opportunity to install improved systems
that provide- increased environmental protection. The modern confinement housing used at many
swine, dairy, veal, and poultry farms allows for waste handling and storage in a fashion that
generates little or no process water. Such systems negate the need for traditional flush systems
and storage lagoons, reduce the risks of uncontrollable spills, and decrease the costs of
transporting manure.
Third, a source would be a new source if construction is begun after the date this rule is
promulgated and its production area and processes are substantially independent of an existing
source at the same site. Facilities may construct additional production areas that are located on
one contiguous property, without sharing waste management systems or commingling waste
streams. Separate production areas may also be constructed to help control biosecurity. New
production areas may also be constructed for entirely different animal types, in which case the
more stringent NSPS requirements for that subcategory would apply to the separate and newly
constructed production area. In determining whether production and processes are substantially
independent, the permit authority is directed to consider such factors as the extent to which the
new production areas are integrated with the existing production areas, and the extent to which
the new operation is engaging in the same general type of activity as the existing source.
EPA also considered whether a certain level of facility expansion, measured as an increase in
animal production, should cause an operation to be subject to new source performance standards.
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Ifso, upon facility expansion, the CAFO would need to go beyond compliance with BAT
requirements to meet the more stringent standards represented by NSPS. In today's proposal,
that increment of additional control, for the swine, poultry and veal subcategories, would amount
to the need to monitor ground water and install liners in lagoons and impoundments to prevent
discharges to ground water that has a direct hydrological connection to surface water; unless the
CAFO could demonstrate that no such direct hydrological link existed. In the beef and dairy
subcategories, the NSPS proposed today are the same as the BAT standards.
EPA considered the same seven options for new source performance standards (NSPS) as it
.considered for BAT. EPA also considered an additional option for new dairies, which if
selected, would prohibit dairies from discharging any manure or process wastewater from animal
confinement and manure storage areas (i.e., eliminating the allowance for discharging overflows
associated with a storm event). New sources have the advantage of not having to retrofit the
operation to comply with the requirements and thus can design the operation to comply with
more stringent requirements. In selecting new source performance standards, EPA evaluates
whether the requirements under consideration would impose a barrier to entry to new operations.
EPA is proposing to select Option 3 as the basis for NSPS for the beef and dairy subcategories.
Option 3 includes all the requirements proposed for existing sources including complying with
zero discharge from the production area except in the event of a 25-year, 24-hour storm and the
requirement to develop a PNP which establishes the rate at which manure and wastewater can be
applied to crop or pasture land owned or controlled by the CAFO. The application of manure
and wastewater would be restricted to a phosphorus based rate where necessary depending on the
specific soil conditions at the CAFO. Additionally, other best management practice requirements
would apply, including the prohibition of manure and wastewater application within 100 feet of
surface water. The proposed new source standard for the beef and-dairy subcategories includes a
requirement for assessing whether the ground water beneath the production area has a direct
hydrological connection to surface water. If a direct hydrological connection exists, the
operation must conduct additional monitoring of ground water up gradient and down gradient
from the production area, and implement any necessary controls based on the monitoring results
to ensure that zero discharge to surface water via the ground water route is achieved for manure
stockpiles and liquid impoundments or lagoons. For the purpose of estimating compliance costs,
EPA has assumed that operations located in areas with a direct hydrological connection will
install synthetic material or compacted clay liners beneath any liquid manure storage and
construct impervious pads for any dry manure storage areas. The operator would be required to
collect and analyze ground water samples twice per year for total dissolved solids, chlorides,
nitrate, ammonia, total coliforms and fecal coliform. EPA is believes that Option 3 is
economically achievable for existing sources. Since new sources are able to install impermeable
liners at the tune the lagoon or impoundment is being constructed, rather than retrofitting
impoundments at existing source, costs associated with this requirement should be less for new
sources hi comparison to existing sources. EPA has concluded that Option 3 requirements will
not pose a barrier to entry for new sources.
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EPA is proposing to establish NSPS for all swine and poultry operations based on Option 5 and
Option 3 combined. In addition the BAT requirements described in Section VQI.C.6, the
proposed new source standards would require no discharge via any ground water that has a direct
hydrological link to surface water. As described above, Option 3 requires all CAFOs to monitor
the ground water and impose appropriate controls to ensure compliance with the zero discharge
standard, unless the CAFO has demonstrated that there is no direct hydrological link between the
ground water and any surface waters. The proposed new source standard also restricts land
application of manure and wastewater to a phosphorus based rate where necessary depending on
the specific soil conditions at the CAFO. Additionally, the same land application best
management practice requirements as required under BAT would apply, including the prohibition
from applying manure and wastewater within 100 feet of surface water.
EPA encourages new swine and poultry facilities to be constructed to use dry manure handling.
Dry manure handling is currently the standard practice at broiler and turkey operations. As
described previously, some existing laying hen operations and most hog operations use liquid
manure handling systems. The proposed new source performance standard would not require the
use of dry manure handling technologies, but EPA believes this is the most efficient technology
to comply with its requirements.
EPA has analyzed costs of installing dry manure handling at new laying hen and swine
operations. Both sectors have operations which demonstrate dry manure handling can be used as
an effective manure management system. The dry manure handling systems considered for both
sectors require that the housing for the animals be constructed in a certain fashion, thus making
this practice less practical for existing sources. Both sectors have developed a high rise housing
system, which houses the animals on the second floor of the building allowing the manure to
drop to the first floor or pit. In the laying hen sector this is currently a common practice and with
aggressive ventilation, the manure can be maintained as a dry product. Hog manure has a lower
solids content, thus the manure must be mixed with a bedding material (e.g., wood chips, rice or
peanut hulls and other types of bedding) which will absorb the liquid. To further aid in drying
the hog manure, air is forced up through pipes installed in the concrete floor of the pit. With
some management on the part of the CAFO operator, involving mixing and turning the hog
manure in the pit periodically, the manure can be composted while it is being stored. The
advantages of the high rise system for hogs and laying hens include a more transportable manure,
which, in the case of the hog high rise system, has also achieved a fairly thorough decomposition.
The air quality inside the high rise house is greatly improved, and the potential for leaching
pollutants into the groundwater is greatly reduced. The design standard of these high rise houses
include concrete floors and also assume that the manure would be retained in the building until it
will be land applied, thus there is no opportunity for storm water to reach the manure storage and
virtually no opportunity for pollutants to leach to groundwater beneath the confinement house.
EPA believes that the cost savings associated with ease of manure transportation, as well as
improved animal health and performance associated with the dry manure handling system for
hogs will off-set the increased cost of operation and maintenance associated with the high rise
hog system. Thus, EPA concludes the proposed;new source performance standards based on the
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high-rise house, does not pose a barrier to entry for either the laying hen and hog sectors.
Although the high rise house is the basis of the new source standards for the swine and laying
hen sectors, operations are not prevented from constructing a liquid manure handling system. If
new sources in these sectors choose to construct a liquid manure handling system, they would be
required to line the lagoons if the operation is located in an area that has a direct hydrologic
connection, but the cost associated with lining a lagoon at the time it is being constructed is much
less than the cost to retrofit lagoon liners. New operations that chose to use a liquid manure
handling system would still be expected to cover these structures to avoid capturing precipitation
which causes an overflow. Covered liquid storage would be smaller than an open storage,
because there wouldn't be capacity included hi the design to accommodate storm water.
EPA proposes to establish new source requirements for the veal subcategory on the basis of
Option 5 which requires zero discharge with no overflow from the production area and Option 3
which requires zero discharge of pollutants to groundwater which has a direct hydrological
connection to surface water, with the ground water monitoring or hydrological assessment
requirements described above. EPA believes that a zero discharge standard without any overflow
will promote the use of covered lagoons, anaerobic digesters or other types of manure treatment
systems. Additionally, this will minimire the use of open air manure storage systems, thus
reducing emission of pollutants from CAFOs.
New veal CAFOs would not be expected to modify existing housing conditions since EPA is not
aware of any existing veal operations that use dry manure handling systems. New veal CAFOs
would be expected to also use covered lagoons to comply with the zero discharge standard. New
veal CAFOs would be required to line their liquid manure treatment or storage structures with
either synthetic material or compacted clay to prevent the discharge of pollutants to ground water
which has a direct hydrological connection to surface water, hi addition, the CAFO would have
to monitor the groundwater beneath the production area to ensure compliance with the zero
discharge requirement. The CAFO would not need to install liners or monitor ground water if it
demonstrates that there is no direct hydrologic link between the ground water and any surface
waters.
In addition to the seven options considered for both existing and new sources, EPA also
investigated a new source option for dairies that would prohibit all discharges of manure and
process wastewater to surface waters, eliminating the current allowance for the discharge of the
overflow of runoff from the production area. To comply with a zero discharge requirement,
dairies would need to transform the operation so they could have full control over the amount of
manure and wastewater, including any runoff, entering impoundments. Many dairies have drylot
areas where calves, heifers, and bulls are confined, as well as similar drylot areas where theO
mature cows are allowed access. EPA estimated compliance costs for a zero discharge
requirements assuming that the following changes would occur at new dairies:
(1) Freestall barns for mature cows would be constructed with six months underpit
manure storage, rather than typical flush systems with lagoon storage;
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(2) ' Freestall barns with six months underpit manure storage would be constructed to
house heifers;
(3) Calf bams with a scrape system would be constructed with a scrape system and
six months of adjacent manure storage; and
(4) New dairies would include covered walkways, exercise areas, parlor holding, and
handling areas.
Drylot areas are continually exposed to precipitation. The amount of contaminated runoff from
such areas that must be captured is directly related to the size of the exposed area and the amount
of precipitation. Under the current regulations, dairies use the 25-year, 24-hour rainfall event (in
addition to other considerations) when determining the necessary storage capacity for a facility.
Imposing a zero discharge requirement that prevents any discharge from impoundments would
force dairies to reconfigure in a way that provides complete control over all sources of
wastewater. EPA considered the structural changes in dairy design described here to create a
facility that eliminates the potential for contaminated runoff.
While EPA believes that confining all mature and immature dairy cattle is technically feasible,
the costs of zero discharge relative to the costs for Option 3 are very high. Capital costs
associated with the construction of the additional bam space to comply with zero discharge
increase the overall cost for this option by two orders of magnitude over the selected option. For
dairies that send their heifers off-site and use hutches for their calves, the costs associated with-
this options would be considerably less. EPA estimates annual operating and maintenance costs
would rise between one to two orders of magnitude above the costs for Option 3. These costs
may create a barrier to entry for new sources. In addition, EPA believes selecting this option
could have the unintended consequence of encouraging dairies to shift calves and heifers offsite
to standalone heifer raising operations (either on land owned by the dairy or at contract
operations) to avoid building calf and heifer bams. If these offsite calf/heifer operations are of a
size mat they avoid being defined as a CAFO, the manure from the immature animals would not
be subject to the effluent guidelines.
EPA is not basing requirements for new dairies on the zero discharge option for the reasons!
discussed above. As an alternative to underpit manure storage, dairies could achieve zero
discharge for parlor wastes and barn flush water by constructing systems such as anaerobic
digesters and covered lagoons. These covered systems, if properly operated, can facilitate
treatment of the manure and offer opportunities to reduce air emissions. The resulting liquid and
solid wastes would be more stable than untreated manure. EPA has not identified any basis for
rejecting the zero discharge option for dairies solely due to animal health reasons.
10.2.8 Pretreatment Standards for New or Existing Sources (PSES AND PSNS)
EPA is not proposing to establish Pretreatment Standards for either new or existing sources.
Further, EPA is withdrawing the existing provisions entitled "Pretreatment standards for existing
sources" at §§412.14,-412.16,412.24,412.26. Those existing provisions establish no limitations.
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The vast majority of CAFOs are located in rural areas that do not have access to municipal
treatment systems. EPA is not aware of any existing CAFOs that discharge wastewater to
POTWs at present and does not expect new sources to be constructed in areas where POTW
access will be available. For those reasons, EPA is not establishing national pretreatment
standards. However, EPA also wants to make it clear that if a CAFO discharged wastewater to a
POTW, local pretreatment limitations could be established by the Control Authority. These local
limits are similar to BPJ requirements in an NPDES permit.
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CHAPTER 11
MODEL FARMS AND COSTS
OF TECHNOLOGY BASES FOR REGULATION
11.0 INTRODUCTION
This Chapter describes the methodology used to estimate engineering compliance costs
associated with implementing the regulatory options proposed for the concentrated animal
feeding operations (CAFOs) industry. Chapter 8 describes in detail the technologies and
practices used as the bases for these options. Chapter 10 describes the regulatory options
considered by the Agency. The results of the economic impact assessment for the regulation are
found in the Economic Analysis of the Proposed Revisions to the National Pollutant Discharge
Eliminations System Regulation and the Effluent Guidelines for Concentrated Animal Feeding
Operations (EA) for the proposed final rulemaking.
The information contained in this Chapter provides an overview of the methodology and
assumptions built into the cost models. More detailed information on the cost methodology and.
specific technologies and practices is contained in the following cost model reports: Cost
Methodology Report for Beef and Dairy Animal Feeding Operations (ERG, 2000a) and Cost
Model for Swine and Poultry Sectors (Tetra Tech, Inc., 2000a).
The following information is discussed in this section:
Section 11.1: Overview of cost methodology;
• Section 11.2: Development of model farm operations;
• Section 11.3: Design and cost of waste and nutrient management technologies;
• Section 11.4: Development of frequency factors;
• Sectionll.5: Summary of estimated model farm costs by regulatory option; and
• Section 11.6: References.
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11.1 Overview of Cost Methodology
To assess the economic impact of the effluent limitations guidelines and standards on the CAFOs
industry, EPA estimated the costs associated with regulatory compliance for each of the
regulatory options described in Chapter 10. The economic burden is a function of the estimated
costs of compliance to achieve the proposed requirements, which may include initial fixed and
capital costs, as well as annual operating and maintenance (O&M) costs. Estimation of these
costs typically begins by identifying the practices and technologies that can be used to meet a
particular requirement The Agency then develops a cost model to estimate costs for their
implementation.
EPA used the following approach to estimate compliance costs for the CAFOs industry:
• EPA collected data from published research, meetings with industry organizations,
discussions with USDA cooperative extension agencies, review of USD A's Census of
Agriculture data, and site visits to swine, poultry, beef, veal, and dairy CAFOs. These
data were used to define model farms and to determine waste generation and nutrient
concentration, current waste and nutrient practices, and the viability of waste
management technologies for the model farms.
* EPA identified candidate waste and nutrient management practices and grouped
appropriate technologies into regulatory options. The regulatory options serve as the
bases of compliance cost and pollutant loading calculations.
• EPA developed cost equations for estimating capital, fixed, 3-year recurring, and annual
O&M costs for the implementation and use of the different waste and nutrient practices
targeted under the proposed regulatory options. Cost equations were developed from
information collected during the site visits, published information, vendor contacts, and
engineering judgment.
• EPA developed and used computer cost models to estimate compliance costs and nutrient
loads for each regulatory option.
• EPA used output from the cost model to estimate total annualized costs and the economic
impact of each regulatory option on the CAFOs industry (presented in the EA).
EPA estimated facility compliance costs for eight regulatory options. Table 11-1 presents the
regulatory options and the waste and nutrient management components that make up each option.
To assess the incremental costs attributable to the proposed rules, EPA evaluated current federal
and state requirements for animal feeding operations and calculated compliance costs of the
proposed requirements that exceed the current requirements. Operations located in states v/hose
requirements meet or exceed the proposed regulatory changes would already be in compliance
with the proposed regulations and would not incur any additional cost. A review of current state
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waste management requirements for determining baseline conditions is included in the record
(See State Compendium: Programs and Regulatory Activities Related to Animal Feeding
Operations Compiled by EPA).
11-2 Development of Model Farm Operations
For the purpose of estimating total costs and economic impacts, EPA calculated the costs of
compliance for CAFOs to implement each of the regulatory options being considered. These
costs reflect the range of capital costs, annual operating and maintenance costs, start-up or first-
year costs, as well as recurring costs that may be associated with complying with the proposed
regulations. EPA traditionally develops either facility-specific or model facility costs. Facility-
specific compliance costs require detailed process information about many, if not all, facilities in
the industry. These data typically include production, capacity, water use, wastewater generation
waste management operations (including design and cost data), monitoring data, geographic
location, financial conditions, and any other industry-specific data that maybe required for the
analyses. EPA then uses each facility's information to determine how the potential regulatory
options will impact that facility, and to estimate the cost of installing new pollution controls.
When facility-specific data are not available, EPA develops model facilities to provide a
reasonable representation of the industry. Model facilities are developed to reflect the different
characteristics found in the industry, such as the size or capacity of operations, types of
operation, geographic locations, modes of operation, and types of waste management operations.
These models are based on data gathered during site visits, information provided by industry
members and their trade associations, and other available information. EPA estimates the
number of facilities that are represented by each model. Cost and financial impacts are estimated
for each model farm, then industry-level costs are calculated by multiplying model farm costs by
the number of facilities represented by each particular model. Because of the amount and type of
information that is available for the CAFOs industry, EPA has chosen a model-facility approach
to estimate compliance costs.
EPA estimated compliance costs using a representative facility approach based on more than 170
farm-level models that were developed to depict conditions and to evaluate compliance costs for
select representative CAFOs. The major factors used to differentiate individual model CAFOs
include the commodity sector, the farm production region, and the facility size (based on herd or
flock size or the number of animals on site). EPA's model CAFOs primarily reflect the major
animal sector groups, including beef cattle, dairy, hog, broiler, turkey, and egg laying operations.
Practices at other subsector operations are also reflected by the cost models, such as replacement
heifer operations, veal operations, flushed caged layers, and hog grow-finish and farrowrto-finish
facilities. Model facilities with similar waste management and production practices were used to
depict operations in regions that were not separately modeled.
11-3
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upstream and downstream of both feedlot and land application areas, 12 times
per year. One composite sample collected once per year at stockpile and surfa
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walkways and handling areas at dairy operations; 100-year, 24-hour storm
capacity requirement at beef and stand-alone heifer operations)
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1 There are no additional compliance costs expected for beef and dairy operations related to
2 Option 5 mandates "drier waste management." For beef feedlots and dairies, this technolo
3 Option 5B mandates "no overflow" systems. For swine operations, the technology basis is
(ERG, 2000a; Tetra Tech, Inc., 2000a).
-------
Another key distinguishing factor incorporated into EPA's model CAFOs is the availability of
cropland and pastureland to apply manure nutrients to land. For this analysis, nitrogen and
phosphorus rates of land application are evaluated for three categories of cropland use:
Category 1 CAFOs have sufficient land for all on-farm nutrients generated, Category 2 CAFOs
have insufficient land, and Category 3 CAFOs have no land. The number of CAFOs within a
given category of land availability is drawn from 1997 USDA data and varies depending on
which nutrient (nitrogen or phosphorus) is used as the basis to assess land application and
nutrient management costs. For Category 2 and 3 CAFOs, EPA evaluated additional
technologies that may be necessary to balance on-farm nutrients. These technologies may also be
used to reduce off-site hauling costs associated with excess on-farm nutrients, as well as to
address ammonia volatilization, pathogens, trace metals, and antibiotic residuals. Such
technologies may include best management practices (BMPs) and various farm production
technologies, such as feed management strategies, solid-liquid separation, composting, anaerobic
digestion, and other retrofits to existing farm technologies.
EPA's model CAFOs also take into account such production factors as climate and farmland
geography, as well as land application and waste management practices and other major
production practices typically found in the key producing regions of the country. Required
practices under existing state regulations are also taken into account. Model facilities reflect
major production practices used by larger confined animal farms, generally those with more than
300 animal units. Therefore, the models do not reflect pasture and grazing type farms, nor do
they reflect typical costs to small farms. EPA's cost models also reflect cost differences within
sectors, depending on manure composition, bedding use, and process water volumes.
11.2.1 Swine Operations
EPA developed the parameters describing the model swine farm using information from the U.S.
Department of Agriculture National Agricultural Statistics Service (NASS), site visits to swine
farms across the country, discussions with the National Pork Producers Council, and the USDA
Natural Resources Conservation Service (NRCS). A description of the various components that
make up the model farm is presented in the following discussion, and the sources of the
information used to develop each piece of the model farm are noted. The Cost Model for Swine
and Poultry Sectors provides more detailed information on the development of the swine model
farm (Tetra Tech, Inc., 2000a). -
11.2.1.1 Housing
Swine are typically housed in total confinement barns, and less commonly hi other housing
configurations such as open buildings with or without outside access and pastures (USDA,
1995). On many farms, small numbers of pigs (fewer than the number covered by this
regulation) are raised outdoors; however, the trend in the industry is toward larger confinement
farms at which pigs are raised indoors (North Carolina State University, 1998). For these
reasons, the model swine farm is assumed to house its animals in total confinement barns.
11-5
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11.2.1.2
Waste Management Systems
The waste produced at an operation depends on the type of animals that are present. In farrow-to-
finish operations, the pigs are born and raised at- the same facility. In grow-finish facilities, young
pigs are first born and cared for at a nursery, and then brought onto the finishing farm. These are
the two predominant types of swine operations in the United States for the size classes that would
be covered under this proposed regulation (North Carolina State University, 1998).
Swine houses typically use slatted floors to separate manure and wastes from the animal. For
example, approximately 40 percent of swine barns have slatted floors directly above a storage pit
or flush alley (USDA, 1995; USDA APHIS, 1996b). This configuration allows the manure to be
worked through the slats and drop into the area below for removal without disturbing or moving
the animals.
The manure collects in a pit under the slats. In the southeast, it is common to allow manure to
collect in the pit, and wash the pit once a day or more with a large volume of water to move the
waste from the pit to a lagoon. The waste is stored in the lagoon until it is applied to land or
transported off site. Storing the waste in an anaerobic lagoon provides some treatment during
storage, conditioning the wastewater for later land application, and reducing odors (North
Carolina State University, 1998).
In the Midwest, a deep pit storage system is more common. Deep pit systems start with several
inches of water in the pit, and the manure is collected and stored under the house until it is
pumped out for field application, typically twice a year, This,system uses less water, creating a
manure slurry that has higher nutrient concentrations than the liquid manure systems.
A 1995 survey of swine operations shows that both lagoons and deep pits are commonly used for
waste storage in the Midwest region (USDA APHIS, 1996c). However, other than a general
increase in the use of deep pits in the northern areas, the extent of the use for each system could
not be determined. EPA intended to model the Mid-Atlantic region as having lagoons, and the
Midwest region as having under house pits. However, the retrofits required for lagoon systems
are more expensive than those for deep pit systems. Therefore, EPA decided to assume that all
facilities use lagoon systems to avoid undercosting retrofit requirements. This is also consistent
with the concept that the Midwest region model represents the Midwest region plus a portion of
all the other regions except the Mid-Atlantic region. In other words, the Midwest region model
reflects parts of the South, Central, and Pacific regions because census data could not be obtained
for all desired regions and size groups (USDA NASS, 1999).
EPA proposes another model farm under Option 5B to provide a dry manure option—the high-
rise swine house, which is a two-story confinement housing design that allows manure to fall
though open slats onto the first floor where it is combined with carbon-rich material. The two
waste management systems used for the model swine farms in this cost model are shown in
Figure 11-1.
-------
Flush System
High-Rise House
11.2.1.3 Size Group
Figure 11-1. Model Swine Farms
The general trend in the U.S. swine industry is toward a smaller number of large operations that
have a larger number of animals on site. The number of smaller facilities, which tend to:house
the animals outdoors, has significantly decreased over the past 10 years (North Carolina State
University, 1998). The trend in the larger operations is toward extended use of confinement
operations.
For this proposed regulation, four size groups were modeled for each type of model farm. The
size groups are provided in Table 11-2.
11-7
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Table 11-2. Size Classes for Model Swine Farms
Region*
Mid-Atlantic
Midwest
Other
National
Operation Type"
combined
slaughter
combined
slaughter
combined
slaughter
combined
slaughter
Average Swine Animal Counts -
(Operation SizePresented by Number of Head)
Medium 1
>750-l,875
1,182
1,242
1,137
1,161
1,255
1,291
1,147
1,176
Medium 2,
>1,875-2,SOO
2,165
2,184
2,152
2,124
2,150
2,215
2,153
2,146
Large 1
>2J500-5,000
3,509
3,554
3,444
3,417
3,455
3,626
3,453
J3,491
Large 2
>5,000-10,000
33,787
20,530
34,164
26,398
66,224
21,731
37,922
22,184
•Mldwest-ND, SD, MN, MI, Wl, OH, IN, tt, IA, MO, ME, KS; Mid-Aflantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV,
KY, TN, NC; Other-ID, MT, WY, NV, UT, CO, AZ, NM, TX, OK, WA, OR, CA, AK, H, AR, LA, MS, AL» GA, SC, FL;.
k Operation type: Combined=breeding inventory, finishing (average of inventoiy and sold/2.8), and feeders (sold/10); Slaughter=finishing
(average of inventory and sold/2.8).
Source: USDANASS, 1999.
11.2.4.4 Region
Data from site visits and North Carolina State University's draft Swine and Poultry Industry
Characterization indicate that the predominant type of waste management system at swine
operations varies from region to region (Norfh Carolina State University, 1998). As previously
mentioned, in the southeast, flush systems are common; in the Midwest, deep-pit storage systems
are more common. Given the regional variances in waste management systems, swine operations
were modeled in two regions across the country: the Midwest and Mid-Atlantic. Facility totals in
other regions were combined into the two regions modeled to account for all facilities
nationwide.
11.2.2 Poultry Operations
EPA developed three model farms to represent poultry operations in the United States. The
model farms are broiler, dry layer, and wet layer operations. The parameters describing the model
poultry farms were developed using information from NASS, site visits to poultry farms across
the country, and the USDA NRCS. A description of the various components of each model farm
is presented in the following discussion, and the sources of the information used to develop each
11-8
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piece of the model farm are noted. The Cost Model for Swine and Poultry Sectors provides more
detailed information on the development of the model poultry farms (Tetra Tech, Inc., 2000a).
11.2.2.1
Housing
The poultry sector includes broilers and layers (layers, pullets, and layer/pullets). Broilers are
typically housed in long bams (approximately 40 feet wide and 400 to 500 feet long; North
Carolina State University, 1998) and are grown on the floor of the house. The floor of the barn is
covered with a layer of bedding, such as wood shavings, and the broilers deposit manure directly
onto the bedding. Approximately 4 inches of bedding are initially added to the houses and top
dressed with about 1 inch of new bedding between flocks.
Layers are typically confined in cages in high-rise housing or shallow pit flush housing. In a
high-rise house, the layer cages are suspended over a bottom story, where the manure is
deposited and stored. In shallow pit flush housing, a single layer of cages is suspended over a
shallow pit. Manure drops directly into the pit, where it is flushed out periodically using recycled
lagoon water. •
These poultry housing systems are considered typical systems in the broiler and layer industry
(North Carolina State University, 1998). Therefore, the cost model uses these housing systems in
the model broiler and wet and dry layer farms.
11.2.2.2
Waste Management Systems
Manure from broiler operations accumulates on the floor where it is mixed with bedding,
forming litter. Litter close to drinking water forms a cake that is removed between flocks. The
rest of the litter in a broiler house is removed periodically (6 months to 2 years) from the bams,
and then transported off site or applied to land. Typically, broiler operations are completely dry
waste management systems (North Carolina State University, 1998).
Layer operations may operate as a wet or a dry system. Approximately 12 percent of layer
houses use a liquid flush system, in which waste is removed from the house and stored in a
lagoon (USDA APHIS, 2000). The remaining layer operations typically operate as dry systems,
with manure stored in the house for up to a year. A scraper is used to remove waste from the
collection pit or cage, area (North Carolina State University, 1998). The lagoon wastewater and
dry manure are stored until they are applied to land or transported off site.
Figure 11-2 presents the waste management systems for broilers and layers.
11.2.2.2 Size Group
For the proposed regulation,-EPA modeled four size groups for broiler and dry layer operations,
and two size groups for wet layer operations. The size groups are presented in Table 11-3 and
Table 11-4.
11-9
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BroflarHouM
CagadUyarHfgh-RlM
Homo
CagtdLayar Shallow Pit
Flush HOUM
Figure 11-2. Model Broiler and Layer Farms
11.2.23
Region
Data from site visits and North Carolina State University's draft Swine and Poultry Industry
Characterization indicate that the predominant type of waste management system at poultry
operations varies from region to region (North Carolina State University, 1998). Most of the
broiler operations in the United States are located in the South and Mid-Atlantic regions, while
most of the egg-laying operations are located in the Midwest and South regions. Therefore, the
model broiler farm reflects the South and Mid-Atlantic regions, and the model layer farm reflects
the Midwest and South regions.
11-10
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Table 11-3. Size Classes for Model Broiler Farms
Region8
Central
Mid-Atlantic -
Midwest
Pacific
South
National
"• Average Chicken BroHerAiiimal Counts* *
Medium 1
>30,000-60,000
44,224
44,193
47,357
44,041
43,998
44.187
Medium 2 -
>60,000-90.,000
73,084
73,590
75,821
73,695
73,776
73,717
Large 1
>90,000-180,000
119,026
• 115,281
118,611
132,560
117,581
117,347
Large^ „
>180,000
332,030
303,155
414,945
624,380
281,453
• Central=ID, MX, WY, NV, UT, CO, AZ, MM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, KS, CT, NJ, PA, DE MD VA, WV KY TN
NC; Midwest=ND, SD, MN, MI, Wf, OH, IN, E, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, ffl; South=AR, LA, MS, AL, GA, SC, FL
BroUers are young chickens of the meat-type breeds, raised for the purpose of meat production. Estimates cover a 12-month period (Dec. 1
through Nov. 30) and exclude states with fewer than 500,000 broilers.
Source: USDANASS, 1999. . • ,
Table 11-4. Size Glasses for Model Dry Layer Farms
Region*
Central
.Mid-Atlantic
Midwest
Pacific
South
National
* •-« Average Chicken EggXayer Counts ~~ ><• ~ ''
Medium 1
>30,000-62,500
42,360
42,588
45,244
43,613
38,642
41,786
Medium 2
>62,500-180,000
89,688
95,585
97,848
99,354
97,413
96,595
Xarge t
>180,000-600,000
317,725
286,946
279,202
277,755
293,512
Xarge 2 ^ ,
>6oo,ooa
733,354
1,007,755
1,229,095
813,356
884,291
•Central=ID, MT, WY, NV, UT, CO, AZ, NM, XX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE MD VA, WV KY TN
NC; Midwest=ND, SD, MN, MI, WI, OH, IN, IL, IA, MO, NE, KS; Pacific=WA, OR, CA, AK, HI; South=AR, LA, MS, AL GA, SC FL '
Source: USDANASS, 1999. . .
11-11
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11.2.3 Turkey Operations
EPA developed one model turkey farm to represent turkey operations in the United States. The
parameters describing the model farm were developed using information from USDA NASS, site
visits to turkey farms across the country, and USDA NRCS. A description of the various
components of the model farm is presented in the following discussion, and the sources of the
information used to develop that piece of the model farm are noted. The Cost Model for Swine
and Poultry Sectors provides more detailed information on the development of the model turkey
farm (Tetra Tech, Inc., 2000a).
11.23.1 Housing
Turkeys are typically housed in long bams (approximately 40 feet wide and 400 to 500 feet long),
similar to broiler systems (North Carolina State University, 1998). The floor of the barn is
covered in a layer of bedding, such as wood shavings, and the turkeys deposit manure directly
onto the bedding. Approximately 4 inches of bedding are initially added to the houses and top
dressed with about 1 inch of new bedding between flocks.
11.23.2
Waste Management Systems
The waste management system at a turkey operation is similar to that at a broiler operation.
Manure from turkey operations accumulates on the floor where it is mixed with bedding, farming
litter. Litter close to drinking water forms a cake that is periodically removed between flocks.
The rest of the litter in the turkey house is removed periodically (6 months to 2 years) from the
bams, and then transported off site or applied to land. Typically, turkey operations are completely
dry waste management systems, and the waste management system at the model turkey farm is
based on this dry system, as shown in Figure 11-3 (North Carolina State University, 1998).
Figure 11-3. Model Turkey Farm
11-12
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11.2.3.3
Size Groups
Three size groups were modeled for each type of facility. The size groups are presented in Table
11-5.
11.2.3.4
Region
State-level data from the 1997 Census of Agriculture indicate that states in the Midwest and Mid-
Atlantic regions of the United States account for over 70 percent of all turkey turkeys produced.
For this reason, model turkey farms are located in the Mid-Atlantic and Midwest regions (USDA
NASS, 1999).
Table 11-5. Size Classes for Model Turkey Farms
Region*
Central
Mid-Atlantic
Midwest
Other
National
Average Turkey Counts Jby Operation Size
Medium 1
>16,500-38,500
25,420
24,903
24,303
26,310
24,936
Medium 2
>38,500-55,pOO "~"
47,310
45,193
45,469
45,520
45,486
Largel
>55,iOOO
172,416
97,111
158,365
116,295,
133,340
•Central=ID, MT, WY, NV, UT, CO, AZ, NM, TX, OK; Mid-Atlantic=ME, NH, VT, NY, MA, RI, CT, NJ, PA, DE, MD, VA, WV, KY, TN,
NC; Midwest=ND, SD, MN, MI, WI, OH, IN, IL, IA, MO, NE, KS; Othet=WA, OR, CA, AK, W, AR, LA, MS, AL, GA, SC FL
Source: USDA NASS 1999.
11.2.4 Dairy Operations
EPA developed two model farms to represent dairy operations in the United States. The model
farms are a complete flush dairy and a hose/scrape dairy. The parameters describing the model
dairy farms were developed using information from NASS, Census of Agriculture, site visits to
dairy farms across the country, meetings with USDA extension agents, and meetings with the
National Milk Producers Federation. A description of the various components that make up the
model farms is presented below, with the sources of the information used to develop that piece of
the model farm. The Cost Methodology Report for Beef and Dairy Animal Feeding Operations
provides more detailed information of the development of the model dairy farm (ERG, 2000a).
11-13
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11.2.4.1 Housing
To determine the type of housing used at the model farm, the type of animals on the farm must be
considered. In addition to the mature dairy herd (including lactating, dry, and close-up cows),
there are often other animals on site, including calves, heifers, and bulls. The number of
immature animals (calves and heifers) at the operation is assumed to be proportional to the
number of mature cows in the herd and depends on the farm's management. For example, the
operation may house virtually no immature animals on site, and obtain replacement heifers from
stand-alone operations, or could have close to a 1:1 ratio of immature animals to mature animals.
The percentage of immature animals on site varies with the size and location of the operation.
For farms with more than 200 dairy cows, there is typically one calf or heifer for every 1.7
mature cows, or 0.6 immature animals for every mature dairy cow (Stall et al., 1998).
For the model farm, EPA estimates the number of calves on site to be 30 percent of the mature
cows, and another 30 percent of the mature cows is used to estimate the number of heifers on
site. The percentage of bulls on site is typically small. For this reason, EPA assumes that their
impact on the model farm waste management system is insignificant, and these animals are not
considered in the model farm.
The most common types of housing for mature cows include freestall barns, tie stalls/stanchions,
pasture, drylots, freestall barns, and combinations of these (Stull et al., 1998). Based on site.
visits, most medium to large dairies (>200 mature dairy cows) house their mature cows in
freestall bams; therefore, EPA assumes that mature dairy cows are housed in freestall barns for
the dairy model. ....... , .-•...•
The most common types of calf and heifer housing are drylots, multiple animal pens, and pasture
(USDA APHIS, 1996a). Based on site visits, most moderate to large facilities use drylots to
house their heifers and calves, so drylots were used in the model farm definition as the housing
for calves and heifers at dairy operations. The size of the drylot for the model farm was
calculated using animal space requirements suggested by Midwest Plan Service (Midwest Plan
Service, 1987).
Under the NSPS Option 8, the model dairy farm is required to eliminate the potential for
discharge; therefore, EPA costed confinement barns for heifer and calf housing to avoid
contaminated runoff from drylots (ERG, 2000a).
11.2.4.2
Waste Management Systems
Waste is generated in two main areas at dairy operations: the milking parlor and the housing
areas. Waste from the milking parlor includes manure and wash water from cleaning the
equipment and the parlor after each milking. Waste from the confinement barns includes
bedding and manure for all bams, and wash water if the barns are flushed for cleaning. Waste
generated from the drylots includes manure and runoff from any precipitation that falls on the
drylot.
11-14
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Site visits showed that most dairy operations send their Waste water from the parlor and flush
barns to a lagoon for storage and .treatment. The wastewater is sometimes passed through a
solids separator to remove solids before the wastewater enters the lagoon. The operator removes
solids from the separator frequently to prevent buildup, and the solids are stockpiled on site.
Solid waste scraped from a barn is typically stacked on the feedlot for storage for later use or
transport. Solid waste on the drylot is often mounded and is later removed for transport off site
or land application. Wastewater in the lagoon is held in storage for later use as fertilizer on site or
transportation off site. The waste management systems used for the model dairy farm in this cost
model are shown in Figure 11-4.
Under the NSPS Option 8, the dairy waste management system is contained in three separate
areas for each animal: the mature dairy cow freestall bam with underpit storage, the heifer
freestall barn with underpit storage, and the calf barn with adjacent manure storage. All manure
and wastewater generated in the milking parlor are channeled to the mature cow manure storage
pit. The manure pits provide storage for the waste until it is applied to the land or transported off
site. The calves at this model farm are also housed in a confinement barn; however, the barn has
a solid floor and the manure waste is scraped to a covered storage area, where is its stored until
the waste is applied to the land or transported off site.
The amount of waste generated at a facility depends on how the operation cleans the barn and
parlor on a daily basis. Some dairy operations flush the waste (a flush dairy); others use less
water, hosing down the parlor and scraping the manure from the barns (a hose/scrape dairy). The
number of facilities that operate as a flush dairy or a hose/scrape dairy was estimated from site
.visits. Both flush and hose/scrape dairy systems were modeled as part of the model farm, and
then the results of each were ultimately weighted to reflect the percentage of operations that are
assumed to be flush versus hose/scrape for a single model farm.
11-15
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Rush Dairy
Solid.
Figure 11-4. Model Dairy Farms
11-16
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11.2.4.3 Size Group
Data collected during site visits indicate that dailies operate differently depending on their size.
For example, larger dairies tend to already have lagoon storage, while moderate-sized dairies
may have only a small amount of storage. Also, because feedlots with more than 700 animals are
already regulated under the current rule, it was assumed for the cost model that these facilities are
already in compliance for many components of the proposed rule. Therefore, three different size
groups were used to model dairy operations with more than 200 animals. The size groups are
presented in Table 11-6.
Table 11-6. Size Classes for Model Dairy Farms
Size Class
Medium 1
Medium 2
Large 1
Size Range
200-350
350-700
>700
Average Head
235
460
1 419
11.2.4.4
Region
Data from site visits indicate that dairies in various regions of the country have different
characteristics primarily related to climate. For example, a dairy in the Pacific region receives a
high amount of rainfall annually, and therefore will produce a high amount of runoff from
drylots. A dairy in the Central region may not have as high rainfall, and will therefore produce
less runoff from drylots. Because operating characteristics may vary between regions, dairies
were modeled in five separate regions: Central, Pacific, South, Mid-Atlantic, and Midwest.
In the Large 1 size group, more than 80 percent of dairy operations are located in the Central and
Pacific regions. In the medium-sized groups, most operations are located hi the Midwest and
Mid-Atlantic regions.
11.2.5 Beef Feedlots
EPA developed one model farm to represent beef feedlot operations in the United States. The
parameters describing the beef model were developed using information from NASS, site visits
to beef feedlots across the country, meetings with USDA extension agents, and meetings with the
National Cattlemen's Beef Association. A description of the various components of the model
farm is presented below, and the sources of the information used to develop that piece of the
model farm are referenced. The Cost Methodology Report for Beef and Dairy Animal Feeding
Operations provides more detailed information of the development of the model beef farm
(ERG, 2000a).
11-17
-------
11.2.5.1
Housing
The large majority of beef feedlot operations in the United States house the cattle on drylots
(USD A, 1996a). There is a small number of operations that use confinement bams at beef
feedlots, but the vast majority use open lots as do most new operations. Therefore, drylots were
assumed as the housing for the model beef farm. The size of the drylot was calculated using
Animal space requirements suggested by Midwest Plan Service ((Midwest Plan Service, 1987).
11.2.5.2
Waste Management System
The drylot is the main area where waste is produced at beef operations. Waste from the drylot
includes solid manure, which has dried on the drylot, and runoff, which results from precipitation
that falls on the drylot
Most beef operations hi the United States divert runoff from the drylot to a storage pond (USDA,
1996a). A solids, separator is sometimes used to remove solids from the waste stream before it
enters the lagoon. Solid waste on the drylot is often mounded to promote drainage away from the
lot to provide consistently dry areas for the cattle to rest, and is later moved from the drylot for
transportation off site or land application on site (USDA APHIS, 1996a).
The beef model farm was developed following these typical characteristics of beef operations.
Figure-11-5 presents the waste management system used as part of the model beef farm.
11.2.53
Size Group
Data collected during site visits indicate that beef feedlots operate differently depending on their
size. For example, larger feedlots frequently put waste through a solid separators before
transferring it to a holding pond, and moderate sized facilities are less frequently equipped with
solids separators. Moreover, feedlots with more than 1,000 beef cattle are already regulated under
the current rule. EPA therefore assumes that these facilities are already hi compliance for many
components of the proposed rule. To account for these differences, four different size groups
were used to model beef operations with more than 300 animal units. The size groups are
presented hi Table 11-7.
11-18
-------
Solids (98.5%)
Figure 11-5. Model Beef Farm
11-19
-------
Table 11-7. Size Classes for Model Beef Farms
Size Class
Medium 1
Medium 2
Large 1
Large 2
.' .'""S£»::kaiige.- '.-;'_;.:?'.'•, ;,'
300-500
500-1,000
1,000-8,000
>8,000
. ' • , ' ''•'.'• AyerageHead "(_ •--.. /^ ,;|
600
1,088
2,628
43,805
11.2.5.4
Region
Data from site visits to beef feedlots indicate that beef operations in various regions of the
country have different characteristics primarily related to climate. For example, a beef feedlot in
the Pacific region receives a high amount of rainfall annually, and therefore will generate a
higher volume of runoff than an operation that receives less annual precipitation. To
accommodate these climatological differences, beef feedlots were modeled for five separate
regions: Central, Pacific, South, Mid-Atlantic, and Midwest.
Approximately 95 percent of Large 1 and Large 2 operations are located in the Central and
Midwest regions. Of the Medium 2 facilities, nearly 75 percent are located in the Midwest
region.
11.2.6 Veal Operations
EPA developed one model farm to represent veal operations in the United States. The parameters
describing the veal model farm were developed using information collected during site visits to
veal operations in Indiana and discussions with the American Veal Association. A description of
the various components of the model farm is presented below, and the sources of the information
used to develop that piece of the model farm are referenced. The Cost Methodology Report for
Beef and Dairy Animal Feeding Operations provides more detailed information of the
development of the model veal farm (ERG, 2000a).
11.2.6.1 Housing
Veal calves are generally grouped by age in an environmentally controlled building. The
majority of veal operations in the United States are equipped with individual stalls or pens with
slotted floors, which allow for efficient removal of waste (Crouch, 1999). Since this type of
housing is the predominant type of housing used in the veal producing industry, environmentally
controlled buildings with individual stalls were designated as the housing for the model veal
farm.
11-20
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11.2.6.2 Waste Management Systems
Based on site visits, the only significant source of waste at veal operations is from the veal
confinement areas. Veal feces are very fluid; therefore, manure is typically handled in a liquid
waste management system. Manure and waste that fall through the slotted floor are flushed
regularly out of the barn. (Typically, flushing occurs twice daily.) Most veal operations have a
lagoon to receive and treat their wastewater from flushing, although some operations have a
holding pit system in which the manure drops directly into the pit, which provides storage until
land application or transport off site. Wastewater in the lagoon is held in storage for later use as
fertilizer on site or for off-site transportation.
EPA developed the veal model farm used in this cost methodology from these general
characteristics. The animals are totally confined, and therefore the only source of wastewater is
from flushing the manure and waste from the barns. Figure 11-6 presents a diagram of the model
veal farm waste management system.
Solids
Freestall
Bam (Flush)
^
Solids
(sometimes
present)
»^
J>
Lagoon
•
i
End Use
Figure 11-6. Model Veal Farm
11.2.6.3
Size Group
The veal industry standard operating procedures do not vary significantly based on the size of
the operation, according to data collected during site visits and discussions with the American
Veal Association (Crouch, 1999). Two size groups were used to model the industry, as presented
in Table 11-8.
Table 11-8. Size Classes for Model Veal Farm
Size Class
Medium 1
Medium 2
Size Range
300-500
>500
Average Head
400
540
.11-21
-------
11.2.6.4
Region
The American. Veal Association indicates that veal producers are located predominantly in the
Midwest and Central regions (Crouch, 1999). Therefore, only these two regions were
incorporated in the model veal farm.
11.2.7 Heifer Grower Operations •<-
EPA developed one model farm to describe heifer grower operations in the United States. The
parameters describing the heifer model farm were developed from information collected during
meetings with the National Milk Producers Federation and discussions with the Professional
Heifer Growers Association. A description of the various components of the model farm is
presented below, and the sources of the information used to develop each piece of the model
farm are noted. The Cost'Meihodology Report for Beef and Dairy Animal Feeding Operations
provides more detailed information of the development of the heifer model farm (ERG, 2000a).
11.2.7.1
Housing
Stand-alone heifer raising operations use two primary methods of housing the animals. One
method is to raise the heifers on pasture, and the second method is to raise the heifers on
confined drylots. Because this regulation addresses only confined operations, the model heifer
farm accounts for animals housed on drylots.
11.2.7.2
Waste Management System
The drylot is the main area where waste is produced at heifer operations. Waste from the drylot
includes solid manure, which has dried on the drylot, and runoff, which results from precipitation
that falls on the drylot.
Heifer operations typically operate like beef feedlots (Cady, 2000). As such, it is assumed that
runoff from the drylot is channeled to a storage pond, sometimes passing through a solids
separator before entering the pond, while solid waste from the drylot is mounded on the drylot,
and is later removed for transportation off site or land application on site.
The waste management system of the model heifer farm is identical to the model beef farm, waste
management system, which is presented in Figure 11-5.
11.2.73 Size Group
There is very little information available on the number of operations raising heifers in
confinement It is believed that most large heifer raising operations (more than 1,000 head) are
confinement-based, while smaller operations are often pasture-based (Cady, 2000). The average
size of heifer grower operations ranges from 50 head to 25,000 head, and varies geographically.
The average size of a heifer operation located west of the Mississippi River is 1,000 to 5,000
11-22
-------
head, while the average size in the upper Midwest, Northeast, and South is 50 to 200 head.
Nationally, the median size of a dairy heifer raising operation is approximately 200 head CCadv
2000). ,
Because of the lack of information on the size distribution of confined heifer grower operations,
EPA chose three size groups for consistency with the model beef farm size groups, as presented'
in Table 11-9. The average head for each size group was calculated as the median on the size
grouprange. .
Table 11-9. Size Classes for Model Heifer Farm
Size Class
Medium 1
Medium 2
Large 1
Size Range
300-500 animals
500-1,000 animals
>1,000 animals
- Average Head -.-: ;' •'•••'.
400
750
1 500
11.2.7.4 Region
There is very little information on the location of heifer grower operations in the United States;
however, since they directly support the dairy industry, it can be assumed that they are
concentrated in areas where the dairy industry is moving toward specialization (Bocher, 2000).
EPA estimates that heifer grower operations are located in four areas of the country: 70 percent
in the west, 20-pereent-in the south/southeast, 7 percent in the northeast, and 3 percent in the
upper Midwest. .
113
Design and Cost of Waste and Nutrient Management Technologies
EPA developed computer cost models to estimate compliance costs for each model farm and
regulatory option.
The cost models calculates model farm costs in three major steps:
1) Costs are calculated for each technology or practice that makes up each regulatory option
for each model farm, based on model farm characteristics, including number of head,
waste characteristics, and facility characteristics.
2) The costs for each technology or practice are then weighted for the entire model farm
population, using frequency factors to indicate the portion of the model farm population
that will incur that cost.
11-23
-------
3) The weighted costs for each model farm population are summed, resulting in an average
model farm cost for each model population.
The resulting model farm cost represents the average cost that all of the operations within that
model population are expected to incur. The compliance costs that a single model farm incurs
may be more or less than this average cost.
The cost estimates generated contain the following types of costs:
• Capital costs—Costs for facility upgrades (e.g., construction projects);
• Fixed costs—One-time costs for items that cannot be amortized (e.g., training);
• Annual operating and maintenance (O&M) costs—Annually recurring costs, which may
be positive or negative. A positive O&M cost indicates an annual cost to operate, and a
negative O&M cost indicates a benefit to operate, due to cost offsets;
• Three-year recurring O&M costs—Costs that occur only once every three years; and
• Annual fertilizer costs—Costs for additional commercial nitrogen fertilizer needed to
supplement the nutrients available from manure application.
These costs provide the basis for evaluating the total annualized costs, cost effectiveness, and
economic impact of the regulatory options proposed for the CAFOs industry.
The following sections discuss the six primary components of the costing methodology:
• The calculation of manure and nutrient production at each operation;
• Cropland acreage; :
• Nutrient management planning;
Facility upgrades; .
Land application; and
• Off-site transportation of manure.
Further detail on the cost methodology may be found in the Cost Methodology Report for Beef
and Dairy Animal Feeding Operations and the report on the Cost Model for Swine and Poultry
Sectors (ERG, 2000a; Tetra Tech, Inc. 2000a).
113.1 Manure and Nutrient Production
* '
The manure produced at each model farm provides the basis for the design of the technology
components and model farm parameters, including determining farm acreage, nutrient
management practices, equipment sizes, and the agronomic rate of applying waste to land. The
quantity and characteristics of the waste for each model farm are calculated from values provided
11-24
-------
in the Agriculture Waste Management Field Handbook for beef and dairy operations, and from
values in Nutrients Available from Livestock Manure Relative to Crop Growth for swine and
poultry operations (USDA NRCS, 1992; USDA NRCS, 1998).
The quantity of manure generated from a feedlot operation depends on the animal type and the
number of mature and immature animals that are present. Nutrient production at each model farm
is calculated using waste characteristics data for excreted manure for each animal type. The mass
production of each of these nutrients is calculated using the average weight of the animal while
housed at the model farm, the waste concentration data, and the number of animals on site. The
total daily rate of manure and nutrient production for each model farm is presented in Table 11-
10, and an example of these calculations is shown in Figure 11-7.
11-25
-------
Table 11-10. Manure and Nutrient Production by Model Farm
Animal Type
3eef
3airy
Dairy-Heifer
)airy-Calves
^eal
leifers
>wine:GF
5wine:FF
-ayers:All
Broiler
Turkey
Size Class
Medium 1
Medium 2
Large 1
Large 2
Medium 1
Medium 2
Large 1
Medium 1"
Medium 2
Large 1
Medium 1
Medium 2
Large 1
Medium 1
Medium 2
Medium 1
Medium 2
Large 1
Medium 1
Medium 2
Large 1
Large 2
Medium 1
Medium 2
Large 1
Large 2
Medium 1
Medium 2
Large 1
Large 2
Medium 1
Medium 2
Large 1
Large 2
Medium 1
Medium 2
Larce 1
Average
Head
600'
1,088
2,628
43,805
235
460
1,419
71
138
426
71
138
. • 426
400
540
400
750
1,500
1,176
2,146
3,491
22,184
1,147
2,153
3,453
37,922
41,786
96,595
287,740
1,027,318
44,187
73,717
117,347
332,073
24,936
45,486
133 340
Total Manure
flbs/day)
33,151
60,113
145,200
2,420,270
30,673
60,041
185,214
2,559
5,009
15,453
1,624
3,178
9,804
6,710
9,059
14,520
27,225
54,450
16,937
30,906
50,277
319,490
12,463
23,395
37,521
. 412,066
: 9,083
, 20,997
62,547
223,313
18,835
31,422
50,019
141,546
12,764
23,284
68255
Nitrogen
Production
Ob/day^
179
324
784
13,062
155.45
304.29
938.67
8
15
47
5
10
30
30
40
44
83
165
72
132
214
1,363
93
175
281
3,082
130
302
899
3,208
267
446
710
2,009
192
350
1.025
Phosphorus
Production ,
(Ib/day)
48
88
212
3,534
28.11
55.02
169.73
2
3
10
1
2
6
7
10
9
18
' 35
21
38
62
395
27
51
82
901
48
112
333
1,190
78
130
206
584
75
136
399
GF «• Grower-Finisher
FF=Farrow-to-Finish
Source: Calculated from manure nutrient values presented in USDA NRCS, 1998 and model farm average head.
11-26
.
-------
Mature dairy cattle (DAIRY, MEDIUM 2 ^&EL FARMED head) produce: •
83.5 Ib manure /day-l,0001b live weight
0.45 Ib nitrogen ClkN)/day-l,000 Ib live weight
0.08 lbphosphorus/day-1, 000 Ib live weight
Average weight = 1,350 pounds
Mature cattle manure (Ib/day) =83.51b * 1.350 Ib * 460 head = 51.854 Ib/dav
day 1,000 Ib farm farm
Nitrogen production frommature cattle (lb/day>= 0.45 Ib * 1350 Ib * 460 head = 279 Ib/dav
day 1,000 Ib farm farm
Phosphorus production from mature cattle (lb/day)= 0.08 Ib * 1.350 Ib * 460 head = 50 Ib/dav
Heifers on site (138 head) produce: Y '
66 Ib manure/day-1,000 Ib live weight
0.2 Ib nitrogen (TKN)/day-l,0001b live weight
0.04 Ib phosphorus/day-1,000 Ib live weight
Average weight = 550 pounds
Heifer manure (Ib/day) = 66 Ib * 550 Ib *138 head = 5.009, Ib/dav
day 1,000 Ib farm farm
Nitrogen production from heifers (lb/dav)= 0.21b*5501b *138 head = 15 Ib/dav
day 1,000 Ib farm farm
Phosphorus production from heifers (Ib/day) = 0.04 Ib * 550 Ib *138 head = 3 lb/d
. , ,',''.'• . day 1,000 Ib farm farm
Calves on site (136 head) produce: ' ' ' ...
65.8 Ib manure/day-1,000 Ib live weight
' 0.2 Ib nitrogen (TKN)/day-l,0001bKve weight
0.04 Ib phosphorus/day-1,000 Ib live weight
Average weight =350 pounds
. Calf manure (Ib/day) = 65.8 Ib * 350 Ib *138faead =3.178 Ib/dav
day 1,000 Ib farm farm
Nitrogen production from calves (lb/dav)= 0.2 Ib * 350 Ib *138 head = 10 Ib/dav
day 1,000 Ib farm farm
Phosphorus production from calves (Ib/day) = 0.04 Ib *350Ib *138 head =2 Ib/dav
• day 1,000 Ib farm farm
TOTAL PHOSPHORUS PRODUCTION = 50 ib + 3 lb + 2 Ib
=551b/da
Figure 11-7. Sample Calculation of Manure and Nutrient Production at Model Farm
11-27
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113.2 Available Acreage
Data on the amount of cropland and pastureland available to facilities for land application of
manure are limited. Therefore, EPA classified the model farms into three categories that define
how much land they have available and how the operation ultimately manages its waste:
Category 1: Facilities with sufficient land to apply all of their generated manure at appropriate
agronomic rates. No manure is transported off site.
Category 2: Facilities without sufficient land to apply all of their generated manure at
appropriate agronomic rates. The excess manure after agronomic application is
transported off site.
Category 3: Facilities without any available land for manure application. All of the manure is
transported off site regardless of the regulatory options considered by EPA.
EPA defines Category 1 operations as having a sufficient amount of land, and at a minimum, the
available land equals the amount of land required to agronomically apply all of the manure
generated at the operation. Category 2 acreages are based on a 1999 USDA analysis that
calculated the amount of nutrients present in manure that exceeded the amount that could be
applied agronomically (Kellogg et al., 2000). These calculations are discussed in detail below.
EPA assumes Category 3 operations have no available land.
11.3.2.1 Agronomic Application Rates
Under all regulatory options considered, all operations are required to implement nitrogen-based
agronomic application rates when applying animal waste or wastewater. Under Options 2
through 8, however, operations that are located hi areas with certain site conditions (e.g.,
phosphorus-saturated soils) are required to follow more stringent phosphorus-based agronomic
application rates. Costs for nitrogen-based application are different than costs for phosphorus-
based application. These costs are weighted for a model farm using a "nutrient-based application
factor" to account for these different costs, based on the percent of facilities in that region that
would apply on a phosphorus-basis verses a nitrogen-basis. The nutrient-based application
factors vary according to the type of facility (beef, dairy, swine, or poultry), and they are
presented in the cost methodology reports (ERG, 2000a; Tetra Tech, Inc., 2000a).
Agronomic application rates are calculated using crop yields, crop uptakes, and crop utilization
factors. These crops vary by region and animal type. EPA selected representative crops for each
model farm by contacting USDA state and county cooperative extension services and
incorporating data from USDA''s Agriculture Waste Management Field Handbook (USDA
NRCS, 1992). The methods used to calculate nutrient requirements and application rates for the
beef and dairy subsectors and the swine and poultry subsectors are described below.
11-28
-------
Beef and Dairy
For the beef and dairy cost model, extension agents identified typical crops grown by'dairy and
beef feedlots in that state, specifying the type of crops grown and typical yields. Crop nutrient
requirements are calculated by multiplying the expected crop yields (obtained from state
cooperative extension services or Census of Agriculture data) by the crop uptake (Lander, 1998)
for both nitrogen (N) and phosphorus (P).
Crop N Requirements (Ib/acre) = Crop Yield (tons/acre) x Crop Uptake (Ib/ton)^^
Crop P Requirements (lb/acre).= Crop Yield (tons/acre) x Crop Uptake (lb/ton)phosphorus
Table 11-11 presents the representative crops, crop yields, crop uptakes, and crop nutrient
(nitrogen and phosphorus) requirements for all animal types by region. EPA does not expect
crops to vary significantly based on the size of the animal operation. Because veal operations are
located predominantly in the Midwest, EPA developed only one set of crop assumptions for veal
that reflect the Midwest region.
When more than one crop is grown on the land over the year (double or triple cropping), EPA set
the total crop nutrient requirement for that land equal to the sum of the individual crop nutrient
requirements.
EPA assumed that 70 percent of the nitrogen and 100 percent of the phosphorus in cattle manure
that is applied to the land would be available for crop uptake and utilization over time (Lander,
1998). Therefore, the agronomic application rate is Calculated as the total crop nutrient
requirement divided by the appropriate utilization factor.
Nitrogen-Based Manure Application Rate (Ib/acre) = Total Crop Nitrogen Requirements (Ib/acre) /70%
Phosphorus-Based Manure Application Rate (Ib/acre) =Total Crop Phosphorus Requirements (Ib/acre) /100%
11-29
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Table 11-11. Crop Information
Animal
Type
Bees'
Heifers
Dairy
Swine
Poultry
Veal
Region
Central
Mid-
Atlantic
Midwest
Pacific
•South
Central
Mid-
Atlantic
Midwest
Pacific
South
Central
Mid-
Atlantic
Midwest
Pacific
South
Central
Mid-
Atlantic
Midwest
Pacific
South
All
(based on
Ivfidwest"^
Crops
Corn-silage
Hay
Com-silage
Alfalfa
Com-silage
Alfalfa
Com-silage
Alfalfa
Winter wheat
Com-silage
Hay
Rye
Com-silage
Hay
Corn-silage
Hay
Corn-silage
Hay
Com-silage
Alfalfa,
Winter wheat
Corn-silage
Hay
Rye
Com
Corn
Soybean
Rye
Com
Soybean
Com chop
Oats
Alfalfa
Bermuda
Bermuda
Com
Soybean
Wheat
Fescue
Com chop
Oats
Alfalfa
Fescue
Com-silage**
Soybeans
"Winter wheat
Crop
yield*
20 tpa
3tpa
27 tpa
6 tpa
20 tpa
6 tpa
24 tpa
8 tpa
18 tpa
17 tpa
2 tpa
3 tpa
20 tpa
3 tpa
17 tpa
2 tpa
17 tpa
2 tpa
24 tpa
8 tpa
18 tpa
17 tpa
2 tpa
3 tpa
162 bpa
83bpa
28 bpa
25 bpa
135 bpa
48 bpa
23 tpa
90 bpa
7 bpa
8 tpa
8 tpa
123 bpa
-27 bpa
63 bpa
5 bpa
23 tpa
102 bpa
7 tpa
5 tpa
138 bpa
42 bpa
46 boa
'.-<'. Crop 1Jptake!(lb/ton) , . , ;
;Nitrogen
7,1
25.6
7.1
0
7.1
0
7.1
0
0.03
7.1
19.8
0.03
7.1
25.6
7.1
19.8
7.1
19.8
7.1
0
0.03
7.1
19.8
0.03
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
0.8 (Ib/bu)
3.6 (Ib/bu)
1 0 (lb/buj
Phosphorus- C
1.1
4.5
1.1
4.7
1.1
4.7
1.1
4.7
0.01
1.1
15.3
0.01
1.1
4.5
1.15
15.3
1.1
15:3-
1.1
4.7
0.01
1.1
15.3
0.01
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
Not calculated
0.2 (Ib/bu)
0.4 ' (Ib/bu)
0 2 (lb/bu)
Crop Requirement ijb/ton)
Nitrogen .,
"147"
77
191
0
142"
0
170
0
0.5
nr
40
0.1
I4T
77
I2T
40
ill
. 40
170
0
1
12T
40
0.1
I39~
67
100
26
ToT
170
160
53
356
15(5
150
98
94
64
99
165
60
352
~w
110
150
47
Phosphorus
" 2T
13
SS"
28
28
38
0.1
IS
31
0.02
13
18
31
18
31
38
0.1
IS
31
0.02
24
12
10
4
2TJ
17
53
10
33
3
5
18
10
13
10
24
11
33
10
67
* tpa=tons per acre; bpa=bushels per acre
** Veal crops based on com-silage 50%, soybeans 50%, and winter wheat 100%
Source: ERG, 2000a; Tetra Tech, 2000a.
11-30
.
-------
Swine and Poultry f
For the swine and poultry model, EPA used published 1997 Census of Agriculture data to
determine the cropland acres of selected crops as apercentage of total harvested crop acres. EPA
determined crop yields by dividing the harvested quantity by the acreage obtained from the 1997
Census of Agriculture and from the yields found in USDA's Agriculture Waste Management
Field Handbook. Using the actual yield data, nutrient requirements and nutrient removal rates
were determined from USDA's Agriculture Waste Management Field Handbook. The average
annual nitrogen and phosphorus crop removal and application rates were calculated by dividing
the total crop requirements over the time to complete a full crop rotation.
11.3.2.2 Category 1 and 2 Acreage
Category 1 acreages are calculated using the agronomic application rates, number of animals,
manure generation estimates, nutrient content of the manure, and manure recoverability factors:
Category 1 Acreage = #Animals * Manure Generation (tons/head) x Nutrient Content fibs/ton manurel x Recoverabilifr
Agronomic application rate (Ib/acre)
Factc
EPA defines recoverability factors as the percentage of manure, based on solids content, that it
would be practical to recover. Recoverability factors are developed for each region, using USDA
state-specific recoverability factors, and are based on the assumption that the decrease in nutrient
value per ton of manure mirrors the reduction in solids content of the recoverable manure (TJSDA
NRQS, 1998). v
Category 2 acreages are estimated using excess manure from USDA's analysis of acres required
to apply excess manure (Kellogg et al., 2000) and, in some cases, Category 1 acreage.
11.3.3 Nutrient Management Planning
To minimize the release of nutrients to surface and ground waters, confined animal feeding
operations must prevent excess application of manure nutrients on cropland through the process
of nutrient management planning. Confined animal feeding operations apply manure nutrients to
the land in the form of solid, liquid, or slurry. Manure is also stored prior to application in
stockpiles, tanks, pits, storage ponds, or lagoons. Confined animal feeding operations prevent
excess application by developing and abiding by appropriate manure application rates that are
designed to add only the nutrients required by the planned crops at the expected yields. Nutrient
management planning may also niinimize releases of nutrients by specifying the timing and
location of manure application.
Five nutrient management practices are included in the costing methodology:
1,
Nutrient management plan—a documented plan developed for each facility to ensure
agronomic application of nutrients on cropland and management of waste on site. The
11-31
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plan includes costs for development of the plan, training and certification, manure
sampling and analysis (collecting samples from solid and liquid waste before each land
application period), soil sampling and analysis (once every 3 years for all phosphorus-
based options), hydrogeologic assessment for facilities located in ground water protection
areas, periodic inspections of on-site facility upgrades, identification and protection of
crop setback areas to protect waterfront areas, calibration of the manure spreader before
each application period, and ongoing recordkeeping and recording. The plan must be
updated at least once every 5 years.
2. Surface water monitoring—a practice in which surface water samples are periodically
collected and analyzed for indications of contaminated runoff into adjacent waters. Costs
account for 12 sampling events per year, including 4 grab samples and 1 quality assurance
sample per event, measuring for nitrate-nitrite, total Kjeldahl nitrogen, total phosphorus,
and total suspended solids.
3. Ground water monitoring—a practice for operations where ground water has a direct
hydrogeologic link to surface water. Costs include installation of four 50-foot ground
water wells and the collection of a sample from each well twice annually for indications
of ground water contamination from the feedlot operation.
4. Feeding strategies—a practice in which the animal feed is monitored and adjusted, to
reduce the quantity of nutrients that are excreted from the animal. Costs include feeding
strategies to reduce nitrogen and phosphorus in excrement from poultry and swine.
5. Timing restrictions—a practice in which manure is land applied only when the land and
crops are most amenable to nutrient utilization. Costs for this practice are calculated for
all animal sectors. .
Each of these practices is discussed in Section 8.0 of this report, and further detail on the design
of each practice may be found in the Cost Methodology Report for Beef and Dairy Animal
Feeding Operations and the report on the Cost Model for Swine and Poultry Sectors (ERG,
2000a; Tetra Tech, Inc., 2000a).
113.4 Facility Upgrades
Section 8.0 of this report describes treatment technologies and facility upgrades that are
presented as part of this cost methodology. These facility upgrades include:
Anaerobic digestion with energy recovery;
Anaerobic lagoons;
Confinement barns for immature animals;
Covered walkways;
Field runoff controls;
11-32.
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• Lagoon covers; * ;
• Liners for lagoons and ponds;
• Manure composting equipment;
• Manure storage;
• Solids separation (settling basin);
• Storage ponds;
• Storm water diversions (berms); and,
• Underpit storage.
An overview of the costs and applicability of each of these upgrades to each of the animal sectors
is presented below:
Anaerobic digestion with energy recovery: Option 6 requires the use of anaerobic
digestion for the largest dairy and swine operations, prior to discharge to a storage lagoon.
The digester is designed to receive waste from all flushing, hose, and scrape operations,
and combines this waste into a reactor to produce methane for energy use at the operation.
Covered lagoon digesters are costed for large flush dairies and swine operations, and
complete mix digesters are costed for large hose dairies. Runoff from the dairy feedlot is
collected separately into a storage pond or lagoon.
Anaerobic lagoons: Costs for anaerobic lagoons are included for facilities that collect
mixtures of water and manure, such as dairies, veal operations, swine, and wet layer
operations. Lagoons receive wastewater from flush bams, flush and hose milking parlors
' (for dairies), and runoff from drylots. They are designed to accommodate a 25-year, '24-
hour storm event and average rainfall for the storage period. The dairy cost model
assumes a minimum depth of 10 feet for an anaerobic lagoon and adjusts this depth to
account for direct precipitation and freeboard, and to optimize the cut-and-fill ratios for
constructing the lagoon. The swine and poultry models design all lagoons as 12 feet deep.
Confinement barns for immature animals: Under NSPS Option 8 for dairies, all
immature animals are housed in confinement barns. This eliminates the need for drylots
and therefore contaminated runoff from the drylots. For calf barns, additional storage area
is included for manure storage.
Covered walkways: Under NSPS Option 8 for dairies, all potential sources of
contaminated runoff are eliminated. Therefore, costs are included to cover animal
walkways and handling areas. The cost to cover holding areas and silage areas per barn
are also included for dairies in this option.
Field runoff controls: Under all options, costs are included to implement and maintain
setbacks along waterbodies contained within land-applied cropland for all animal
operations. The size and therefore the cost of the setback were calculated based on
11-33
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national.estimates of land area and stream miles and the average size and cost of filter
strips (USEPA, 2000; USEPA, 1993).
Lagoon covers: Under Option 5, the regulation requires that facilities have zero potential
for discharge from the feedlot. This requirement may be met by covering liquid storage
basins and preventing direct precipitation from entering and adding to the storage volume.
Swine, wet layers, and veal operations under Option 5 have costs for lagoon covers.
Liners for lagoons and ponds: The regulation requires mat operations that store animal
waste (e.g., runoff and/or process water) in a lagoon or pond have a liner in place if they
are located in an area-where ground water has a hydrogeologic connection to surface
water. The liner is composed of two parts: a synthetic portion and a clay portion. The
liner is designed to cover the floor of the pond or lagoon, including sloped side walls.
Costs are calculated for all animal sectors to install liners in their lagoons and ponds.
Manure composting equipment: EPA designed windrow composting systems to-treat
and manage manure waste from drylots, separated solids, and scraped manure under
Option 5 for beef, dairy, and'heifer operations. Mortality composting systems are
designed for swine and poultry operations ,to manage mortality waste under all options.
Manure storage: The cost model includes costs for the installation and maintenance of
concrete pads as part of the waste management system for beef, heifer, and dairy
operations under Options 3 and 4. The pads are designed to store waste from drylots,
'separated solids, and scraped manure: The cost model also includes costs for dry storage
of poultry manure as part of all regulatory options. Storage for poultry litter includes a
storage structure with a roof, a foundation, and a floor; and the structure receives poultry
manure and bedding waste from the poultry house after each cleanout.
Solids separation (settling basin): The cost model includes solids separation as part of
facility upgrades for beef and dairy operations, to facilitate the management of manure
waste by separating the solid portion from the liquid portion. EPA costed earthen
separators for beef feedlots, where runoff is the largest expected flow through the
separator, and concrete-lined separators for dairy operations, where large amounts of
flush water pass through the separator. Concrete is used to prevent erosion of the side
slopes of the separator.
Storage ponds: The cost model includes the costs of storage ponds for facilities that
collect runoff from the feedlot, such as beef facilities in which the cattle are confined on
dry lots. The storage pond receives waste from drylot runoff only and is designed to
accomodate a 25-year, 24-hour storm event and average rainfall for the storage period.
Storm water diversions (berms): Under all regulatory options, EPA requires that all
animal operations contain any runoff collecting in potentially contaminated areas. EPA
11-34
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assumes that large facilities already have storm water diversions in place, because it is
required by the current regulation.
Underpit storage: Under NSPS Option 8 for dairies, the cost model includes the costs of
underpit storage as the waste management system for the mature cow confinement barns
and the heifer barns. The cost model includes a bam designed with a slatted floor, and
the cows work the manure through the slats into a storage pit underneath the barn.
Ventilation in the pit is required for the pit to remove toxic gases, and the manure is
stored in the pit until it can be agronomically applied to the land or transported off-site.
EPA calculated the costs of facility upgrades using design specifications in combination with
cost estimates for each portion of the upgrade (e.g., excavation, compaction, gravel fill, etc.).
Design specifications were obtained from various sources, including the Natural Resources
Conservation Service (Conservation Practice Standards), the Midwest Plan Service, the
Agricultural Waste Management Field Handbook, and other engineering design sources. EPA
combined these design specifications with model-farm information—such as the animal type,
manure generation, housing methods, and the type of farm—to calculate the required size of the
component as well as the materials and labor required to construct and operate the upgrade. Then
cost-estimation guides—including Means Building Construction Cost Data, Means Heavy
Construction Cost Data, Richardson's, EPA's FarmWare Model, and vendor-supplied cost-
data—were used to determine the costs of each component of the upgrade.
11.3.5 Land Application
The cost model calculates costs for land application of manure and other waste for those
operations which have land, but are not currently applying their waste. Based on site visits, EPA
estimates that all beef, dairy, veal, and heifer operations that have land already have equipment to
apply dry waste. Operations that have ponds or lagoons in place similarly have some form of
liquid application method available. However, operations that are estimated to build lagoons or
ponds in response to the regulation are costed for new equipment to apply liquid waste. These
costs are based on installation and operation of a center pivot irrigation system from vendor
supplied cost data (Zimmatic, Lie., 1999). For swine and poultry operations, EPA estimated
(based on site visits) that all facilities already apply their waste to the land, and no additional
costs would be incurred under the regulatory options.
11.3.6 Off-Site Transport of Manure
Animal feeding operations use different methods of transportation to remove excess manure
waste and wastewater from the feedlot operation. The costs associated with transporting excess
waste off site were calculated using two methods: contract hauling waste or purchasing
transportation equipment. For poultry and swine operations, EPA based transportation costs on
operations contract hauling their waste. For beef and dairy operations, EPA based transportation
11-35
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costs on either contract hauling or purchasing equipment to self-haul waste (whichever was least
expensive).
Contract Hauling: EPA evaluated contract hauling as a method of transporting manure waste
off site. In this method, the animal feeding operation hires an outside company to transport the
excess waste. This method is advantageous to-facilities that do not have the capacity to store
excess waste on site, or the cropland acreage to agronomically apply the material. In addition,
this method is useful for facilities that do not generate enough excess waste to warrant
purchasing their own waste transportation trucks.
No capital costs are associated with contract hauling—only the operating cost to haul the waste.
For beef and dairy operations, EPA calculated a set rate per mile for solid waste and for liquid
waste, using vendor-supplied quotations and the average hauling distance for each region (ERG,
2000b; Tetra Tech, Inc., 2000b). For swine and poultry operations, EPA extracted the costs of
contract hauling solid waste and liquid waste from many published articles (Tetra Tech, Inc.,
1999).
Purchase Equipment: Another method evaluated for the transport of manure waste off site
involves purchasing transportation equipment, hi this method, the feedlot owner is responsible
for purchasing the necessary trucks and hauling the waste to an off-site location. Depending on
the type of waste to be transported, a solid waste truck, a liquid tanker truck, or both types of
trucks would be required. In addition, the feedlot owner is responsible for determining a suitable
location to transport the waste, as well as all costs associated with loading and unloading the
trucks, driving the trucks to the off-site location, and marntaining the tracks. EPA did not base
compliance costs for swine and poultry operations on purchasing transportation equipment, and
therefore no costs are calculated for these facilities under this transportation option.
The capital and annual costs associated with the purchase and operation of a truck for waste
transport depend on the type of waste (solid or liquid) and the quantity of waste to be transported.
The cost model includes an evaluation of the amount of solid and/or liquid waste the operation
will ship off site, and a determination of the capital costs based on that information. Annual costs
are also calculated using the quantity of liquid or solid waste, as well as the hauling distance,
maintenance costs, labor, fuel rates, and other parameters (ERG, 2000b).
i r ''•" -.
4 £ .^V-.;1,
11.4 Development of Frequency Factors 3|PsK-
EPA recognizes that individual farms have already implemented certain waste management
techniques or practices described in Section 11.3. When estimating costs for the implementation
of the proposed options, EPA did not include costs for practices or techniques akeadydn*place at
the farm.
To do this, EPA estimated the current frequency of existing waste management practices at
swine, poultry, beef, veal, heifer, and dairy operations to estimate the portion of the operations
11-36
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that would incur costs to comply with the new regulation. EPA used the frequency information
to estimate compliance costs for specific model farms for the regulatory options being
considered. For example, based on site visits, all broiler operations are assumed to own or have
access to tractors with front-end loaders for use in cleaning out the broiler houses (the frequency
factor is 100 percent); therefore, no costs are included for cleaning out the broiler houses. As
another example, 40 percent of large beef feedlots are estimated to have settling basins (based on
site visits); therefore, only 60 percent of large beef feedlots incur a cost for a settling basin.
Applying the frequency factors to the unit component costs reduces the effective cost of that
component for the model farm. Essentially, EPA adjusts the component cost to account for those
facilities which already have the component in place, and would not have to install and operate a
new component as a result of the proposed regulation.
EPA estimated frequency factors based on the sources below (each source was considered along
with its limitations):
• EPA site visit information—This information was used to assess general practices of
animal feeding operations and how they vary between regions and size classes.
Observations by industry experts—Experts on animal feeding operations were
contacted to provide insight into operations and practices, especially where data were
limited or not publicly available.
USDA NASS—-The data currently available from NASS were used to determine the
distribution of animal feeding operations across the regions by size class.
USDA APHIS National Animal Health Monitoring System (NAHMS)—This source
provides information on animal housing practices, facility size, and waste system
components sorted by size class and region. These data have limited use because of the
small number of respondents in the size classes of interest..
State Compendium: Programs and Regulatory Activities Related to AFOs—This
summary of state regulatory programs was used to estimate frequency factors based on
current waste-handling requirements that already apply to animal operations in various
states and in specific size classes.
11-37
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11.5 Summary of Estimated Model Farm Costs bv Regulatory Option
A summary of the estimated regulatory compliance costs is provided in the following tables.
Capital, fixed, annual, and 3-year recurring (and, in some cases, 5-year) costs are included for
each animal sector and each of the eight regulatory options. Costs are presented in 1997 dollars.
Table 11-12:
Table 11-13:
Table 11-14:
Table 11-15:
Table 11-16:
Table 11-17:
Table 11-18:
Regulatory Compliance Costs
Regulatory Compliance Costs
Regulatory Compliance Costs
Regulatory Compliance Costs
Regulatory Compliance Costs
Regulatory Compliance Costs
Regulatory Compliance Costs
for Swine Operations
for Poultry Operations
for Turkey Operations
for Dairy Operations
for Beef Operations
for Veal Operations
for Heifer Operations
11.6 References
Bocher, L.W. 2000. Custom Heifer Grower...Specialize in Providing Replacements for Dairy
Herds. Hoards Dairyman. January 10,2000.
Cady, R. 2000. Telephone conversation with Dr. Roger Cady, Monsanto Company and-Founder
of the Professional Dairy Heifer Growers Association. February 18, 2000.
Crouch, A. 1999. Telephone conversation with Alexa Crouch, American Veal Association.
October 14,1999.
ERG. 2000a. Cost Methodology Report for Beef and Dairy Animal Feeding Operations.
Prepared for U.S. Environmental Protection Agency, Office of Water, Washington, DC.
December 2000.
ERG. 2000b. Transportation of Waste Off Site for Beef and Dairy Cost Model Memorandum
prepared for U.S. Environmental Protection Agency, Office of Water, Washington, DC.
December 2000.
Kellogg, R., C. H. Lander, D. Moffitt, and N. GoUehon. 2000. Manure Nutrients Relative to the
Capacity of Cropland and Pastureland to Assimilate Nutrients: Spatial and Temporal
Trends for the U.S. U.S. Department of Agriculture, National Resource Conservation
Service, Washington, DC.
Midwest Plan Service. 1987. Beef Housing and Equipment Handbook. Fourth Edition, MWPS-6,
Iowa State University, Ames, Iowa. February 1987.
NCSU. 1998. Draft Swine and Poultry Industry Characterization, Waste Management Practices
and Model Detailed Analysis of Predominantly Used Systems. Prepared for
11-38
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Environmental Protection Agency (WA 1-27) by North Carolina State University,
September 30,1998.
Stull, C. E., Steven B., and E. DePeters, eds. 1998. Animal Care Series: Dairy Care Practices.
2nd ed. Dairy Workgroup, University of California Cooperative Extension, Davis,
California. June 1998.
Tetra Tech. 2000a. Cost Model for Swine and Poultry Sectors. Prepared for U.S. Environmental
Protection Agency, Office of Water, Washington, DC. November 2000.
Tetra Tech. 2000b7 Revised Transportation Distances for Category 2 and 3 Type Operations.
Memorandum prepared for U.S. Environmental Protection Agency, Office of Water,
. Washington, DC. January 7,2000.
Tetra Tech. 1999. Costs of Storage, Transportation, and Land Application of Manure.
Memorandum prepared for U.S. Environmental Protection Agency, Office of Water,
Washington, DC. February 1999.
USDA APHIS. 2000. Pan II: Reference of 1999 Table Egg Layer Management in the United
States-(L,ayer-'99):'~(3.Sr. Department of Agriculture, Animal Plant Health Inspection
Service, Fort Collins, CO.
USDA APHIS. 1996a. National Animal Health Monitoring System, Parti: Feedlot Management
'Practices, http://www.aphis.usda.gov/vs/ceah/cahm/ File cofdesl.pdf. U.S. Department
of Agriculture, Animal and Plant Health Inspection Service, Washington, DC.
USDA APHIS. 1996b. Swine '95: Part II: Reference of 1995 Grower/Finisher Health and
Management. U.S. Department of Agriculture, Animal and Plant Health Inspection
Service, Washington, DC.
USDA APHIS. 1996c. National Animal Health Monitoring System, Pan 1: Reference of 1996
Dairy Management Practices. U.S. Department of Agriculture, Animal and Plant Health
Inspection Service, Washington, DC.
USDA APHIS. 1995. Swine '95: Pan I: Reference of1995 Swine Management Practices. U.S.
Department of Agriculture, Animal and Plant Health Inspection Service, Washington,
DC:
USDA NASS. 1999. Queries run by NASS for USEPA on the 1997 Census of Agriculture data.
U.S. Department of Agriculture, National Agricultural Statistics Service, Washington,
DC.
11-39
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USDANRCS. 1992. Agricultural Waste Management Field Handbook, National Engineering
Handbook (NEH), Part 651. U.S. Department of Agriculture, Natural Resources
Conservation Service, Washington, DC.
USDANRCS. 1998. Nutrients Available from Livestock Manure Relative to Crop Growth
Requirements. Resource-Assessment and Strategic Planning Working Paper 98-1.
USEPA. 1993. Guidance Specifying Management Measures for Sources of'Nonpoint Pollution in
Coastal Waters. EPA840-B-92-002. U.S. Environmental Protection Agency, Office of
Water Washington, DC. :
USEPA. 2000. Water Quality Conditions in the United States. EPA#841-F-00-006. U.S.
Environmental Protection Agency, Office of Water. Washington, D.C.
Zimmatic, Inc. 1999. Cost Estimate for Center Pivot Irrigation Systems,
.
11-40
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