5783
UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION 5
230 S DEARBORN ST
CHICAGO, ILLINOIS 60604
905R76114
JULY 1976
ENVIRONMENTAL
IMPACT STATEMENT
DRAFT
Part II Organic Solids Reuse Plan
and Environmental Assessment
Prepared by Madison Metropolitan Sewerage District,
Dane County, Wisconsin
Ch;c,
-------
•• CONTENTS
Page
Letter of Transmittal
Acknowledgements i
Chapter 1 INTRODUCTION 1-1
1.1 SCOPE OF STUDY 1-1
1.2 HISTORY OF SLUDGE DISPOSAL AT NINE SPRINGS
TREATMENT WORKS 1-2
1.3 PAST REPORTS ON SLUDGE DISPOSAL 1-3
Chapter 2 REVIEW OF SLUDGE DISPOSAL ALTERNATIVES
CONSIDERED 2-1
2. 1 GREELEY AND HANSEN REPORT 2-1
2.2 WESTON REPORT 2-1
2.3 MMSD ADDENDUM TO WESTON REPORT 2-2
2.4 MMSD DECISION 2-3
Chapter 3 LAND APPLICATION OF SLUDGE
STATE OF THE ART 3-1
3.1 GENERAL 3-1
3.2 EXISTING SYSTEMS 3-2
Metropolitan Sanitary District of Greater
Chicago (MMSD) 3-2
West Hertfordshire Main Drainage Authority,
Great Britain 3-5
Los Angeles County Sanitary District
Composting System 3-8
City of Boulder, Colorado 3-9
Metropolitan Denver Sewage District No. 1 3-9
City of Salem, Oregon 3-10
Other Locations 3-10
3.3 RESEARCH AND REPORTS 3-11
University of Wisconsin Research 3-11
Other Major Reports 3-12
3.4 SUMMARY 3-12
Chapter 4 TREATMENT PLANT SLUDGE
CHARACTERIZATION 4-1
4. 1 CHARACTER OF SLUDGE PRESENTLY PRODUCED 4-1
Sampling and Analysis Procedures 4-1
ii
-------
Page
Chapter 4 (Continued)
Results of Analysis 4-2
Discussion of Results 4-3
4.2 CHARACTER OF SLUDGE PRODUCED IN THE FUTURE 4-4
Quality of Sludge 4-5
Quantity of Sludge 4-5
Implications of a Future Phosphorus Removal
Requirement 4-6
Summary 4-7
Chapter 5 SLUDGE LAGOON STUDY 5-1
5.1 BACKGROUND 5-1
5.2 DESCRIPTION OF LAGOONS AND DEPOSITS 5-2
Field Work Methodologies 5-2
Results of Field Work 5-6
5.3 CHEMICAL ANALYSES OF FIELD SAMPLES 5-7
Characterization of Lagoon Sludge 5-7
Discussion of Results 5-7
Leaching of Lagoon Constituents 5-10
Summary 5-13
5.4 LAGOON EMBANKMENT EVALUATION 5-13
Conclusions 5-13
Recommendations 5-14
Later Investigations 5-14
5.5 LAGOON ABANDONMENT 5-14
Option 1—Storage of Treatment Plant Sludge 5-15
Option 2—Removal of Lagoon Sludge 5-15
Option 3—Lagoon Supernatant Removal 5-18
Option 4—Stabilization of Lagoon Dikes 5-22
5.6 ALTERNATIVE ABANDONMENT PROGRAMS 5-23
Abandonment Program 1 5-24
Abandonment Program 2 5-24
Abandonment Program 3 5-26
Comparison of Lagoon Abandonment Programs 5-27
5.7 RECOMMENDED LAGOON ABANDONMENT PROGRAM 5-27
General Description 5-27
Implementation 5-28
5.8 SUMMARY 5-30
Chapter 6 CONSIDERATIONS FOR AGRICULTURAL REUSE
OF SLUDGE 6-1
6.1 STUDY AREA DESCRIPTION 6-1
Agriculture 6-1
Climate 6-2
Ground Water 6-2
Land Use 6-4
6.2 REGULATIONS 6-6
Local Regulations 6-6
-------
ORGANIC SOLIDS REUSE PLAN
-------
Page
Chapter 6 (Continued)
State Regulations 6-6
Federal Regulations 6-8
6.3 SLUDGE APPLICATION RATE DEVELOPMENT 6-9
Soil Suitability for Sludge Application 6-9
Crop Suitability for Sludge Application 6-14
Annual Sludge Application Limits 6-15
Total Sludge Application Limits 6-17
Summary of Sludge Application Rates 6-20
6.4 OTHER CONSIDERATIONS FOR AGRICULTURAL REUSE 6-22
Fertilizer Market 6-22
Farm Community Acceptance of Sludge Reuse 6-23
Land Ownership 6-23
Sludge Application Periods 6-25
Soil Wetting Effect of Sludge 6-26
Odors 6-27
Insects 6-27
Weeds 6-27
Public Health Aspects 6-28
Sludge Drying Considerations 6-2S
Nitrogen Losses During Application 6-30
6.5 SLUDGE APPLICATION SITE INVESTIGATION 6-30
Land Requirement for Sludge Reuse 6-30
Site Suitability Criteria 6-31
Land Available for Sludge Reuse 6-32
6.6 SUMMARY 6~33
Chapter 7 SLUDGE REUSE PROGRAMS 7-1
7,1 CRITERIA FOR PROGRAM SELECTION 7-1
Program Criteria 7-1
Reuse Programs Eliminated 7-2
7.2 ACCEPTABLE SLUDGE REUSE PROGRAMS 7-2
Reuse Program 1—Market All Sludge 7-3
Reuse Program 2--Lease Land for Sludge
Application 7-5
Reuse Program 3—Combination Sludge Marketing
and Land Leasing 7-7
7.3 SLUDGE HANDLING CONTINGENCY PLAN 7-7
7.4 PRESENT METHOD OF SLUDGE REUSE 7-8
7.5 FUTURE SLUDGE HANDLING FACILITIES CONSIDERED 7-9
Transport Facilities 7-10
Sludge Storage Facilities 7-12
Sludge Application Methods 7-14
Comparison of Sludge Application Methods 7-24
7.6 COMPARISON OF SLUDGE REUSE PROGRAMS 7-26
Farmer Acceptance 7-26
Cost Comparison 7-26
Recommended Sludge Reuse Program 7-27
IV
-------
Page
Chapter 8 RECOMMENDED SLUDGE REUSE PROGRAM 8-1
8.1 REUSE PROGRAM DESCRIPTION 8-1
8.2 PROGRAM MANAGEMENT 8-1
Program Manager 8-2
Initial Interview and Site Screening 8-2
Sludge Application Rate Determination 8-3
Recordkeeping 8-4
8.3 MONITORING PROGRAM 8-4
Sludge Monitoring 8-4
Soil Monitoring 8-4
Crop Monitoring 8-6
Ground-Water Monitoring 8-6
Records and Data Review 8-7
Monitoring Program Costs 8-7
8.4 MARKETING PROGRAM 8-7
8.5 SLUDGE HANDLING FACILITIES 8-9
Sludge Application Equipment 8-12
Sludge Transportation Facilities 8-12
8.6 REUSE PROGRAM COST 8-13
Construction Cost 8-13
Program Operation Requirements 8-14
Sludge User Fee 8-17
Program Cost Summary 8-17
Chapters SUMMARY, CONCLUSIONS, AND RECOM-
MENDATIONS 9-1
9.1 INTRODUCTION 9-1
9.2 REVIEW OF SLUDGE DISPOSAL ALTERNATIVES CONSIDERED 9-1
9.3 LAND APPLICATION OF SLUDGE STATE OF THE ART 9-2
9.4 TREATMENT PLANT SLUDGE CHARACTERIZATION 9-2
9.5 SLUDGE LAGOON STUDY 9-3
9.6 CONSIDERATIONS FOR AGRICULTURAL REUSE OF SLUDGE 9-4
9.7 SLUDGE REUSE PROGRAMS CONSIDERED 9-4
9.8 RECOMMENDED SLUDGE REUSE PROGRAM 9-7
9.9 RECOMMENDATIONS AND IMPLEMENTATION SCHEDULE 9-9
REFERENCES R-1
APPENDIX A SLUDGE LAGOON CHEMICAL DEPTH PROFILES A-1
APPENDIX B COST ESTIMATING AND CALCULATION PROCEDURES
FOR SLUDGE REUSE PROGRAM PLANNING B-1
APPENDIX C SOIL PROPERTIES AND SUITABILITY FOR
SLUDGE APPLICATION C-1
APPENDIX D SLUDGE REUSE PROGRAM MANAGEMENT TOOLS D-1
APPENDIX E MONITORING PROGRAM E-1
v
-------
TABLES
Page
Chapter 3
TABLE 3-1
TABLE 3-2
Chapter 4
TABLE 4-1
TABLE 4-2
TABLE 4-3
TABLE 4-4.
Chapter 5
TABLE 5-1
TABLE 5-2
TABLE 5-3
Chapter 6
TABLE 6-1
TABLE 6-2
TABLE 6-3
TABLE 6-4
THREE BASIC CATEGORIES FOR WASTE
ORCANICS APPLICATION TO LAND
OTHER SLUDGE REUSE PROGRAMS
CHARACTERIZATION OF TREATMENT
PLANT ORGANIC SOLIDS
SUMMARY OF NITROGEN ANALYSIS OF
MMSD DIGESTED SLUDGE
SUMMARY OF EXPECTED TREATMENT
PLANT ORGANIC SOLIDS QUALITY
SUMMARY OF EXPECTED TREATMENT
PLANT ORGANIC SOLIDS QUANTITY
CHARACTERIZATION OF LAGOON SLUDGE
SUMMARY LAGOON ORGANIC SOLIDS
CHARACTER AND QUANTITY
COMPARISON OF LAGOON ABANDON-
MENT PROGRAMS
NORMAL STUDY AREA TEMPERATURE
AND PRECIPITATION
CROP PLANTING AND HARVESTING DATES
AND RESTRICTIONS FOR SLUDGE REUSE
ANNUAL FERTILIZER REQUIREMENTS
TOTAL SLUDGE APPLICATION BASED
ON IRRIGATION WATER QUALITY
CRITERIA
3-1
3-11
4-2
4-3
4-7
4-8
5-9
5-13
5-28
6-2
6-14
6-15
6-19
VI
-------
Page
Chapter 6 (Continued)
TABLE 6-5
TABLE 6-6
TABLE 6-7
Chapter 7
TABLE 7-1
Chapter 8
TABLE 8-1
TABLE 8-2
TABLE 8-3
TABLE 8-4
Appendix B
TABLE B-1
TABLE B-2
TABLE B-3
TABLE B-4
TABLE B-5
TABLE B-6
TREATMENT PLANT ORGANIC SOLIDS
ANNUAL AND TOTAL APPLICATION
RATES ACCORDING TO SOIL CLASS
AND CROP TYPE
LAGOON ORGANIC SOLIDS ANNUAL
AND TOTAL APPLICATION RATES
ACCORDING TO SOIL CLASS AND CROP
TYPE
ESTIMATED MONTHLY DISTRIBUTION OF
SLUDGE USE ON PRIVATE FARMLAND
COMPARISON OF SLUDGE APPLICATION
METHODS
ESTIMATED INITIAL CONSTRUCTION
COST SLUDGE REUSE PROGRAM
ESTIMATED INITIAL ANNUAL
OPERATION AND MAINTENANCE COSTS
EXAMPLE SLUDGE USE FEES
PROGRAM COST SUMMARY
NEW LAGOON COST DETERMINATION
LAGOON SLUDGE REMOVAL COST
DETERMINATION
REHABILITATE WEST HALF OF
LAGOON 1 COST DETERMINATION
LAGOON SUPERNATANT TREATMENT
ALTERNATIVES
LAND LEASE COST DETERMINATION
TRUCK TRANSPORTATION COST
DETERMINATION
6-21
6-21
6-26
7-21
8-13
8-17
8-19
8-20
B-4
B-4
B-5
B-5
B-6
B-6
vn
-------
Appendix B (Continued)
TABLE B-7
TABLE B-8
TABLE B-9
TABLE B-10
TABLE B-11
TABLE B-12
TABLE B-13
TABLE B-14
Appendix C
TABLE C-1
Appendix D
TABLE D-1
TABLE D-2
TABLE D-3
TABLE D-4
TABLE D-5
TABLE D-6
TABLE D-7
TABLE D-8
PIPELINE TRANSPORTATION
DETERMINATION
SMALL ON-FARM LAGOON COST
DETERMINATION
SPRINKLER APPLICATION COST
DETERMINATION
OIL INJECTION COST
DETERMINATION
TRUCK SLUDGE SPREADER COST
DETERMINATION
TRACTOR SLUDGE SPREADING COST
DETERMINATION
MONITORING PROGRAM COST
DETERMINATION
SLUDGE REUSE PROGRAM YEAR-BY-
YEAR COST ESTIMATE
SOIL PROPERTIES AND SUITABILITY
FOR SLUDGE APPLICATION
SLUDGE USER AND FIELD
IDENTIFICATION
SITE INVESTIGATION CHECKLIST
SOIL MONITORING DATA
CROP MONITORING DATA
GROUND WATER MONITORING DATA
SLUDGE APPLICATION RECORDS
ANNUAL RECORD
TOTAL SLUDGE APPLICATION RATE
WORKSHEET
Page
B-7
B-7
B-7
B-8
B-8
B-9
B-9
B-10
C-1
D-3
D-5
D-6
D-7
D-8
D-9
D-10
D-13
vat
-------
Appendix D (Continued)
TABLE D-9
Appendix E
TABLE E-1
TABLE E-2
TABLE E-3
TABLE E-4
TABLE E-5
ANNUAL SLUDGE APPLICATION RATE
WORKSHEET
SLUDGE ANALYSIS PROCEDURES
REFERENCES
SOIL ANALYSIS PROCEDURES
REFERENCES
SUGGESTED MAXIMUM TOLERANCE
LEVELS FOR VARIOUS ELEMENTS
IN SUCCULENT PLANT TISSUE
SUGGESTED PLANT PARTS FOR
SAMPLING
PLANT TISSUE ANALYSIS PROCEDURES
REFERENCES
Page
D-17
E-3
E-6
E-7
E-7
E-8
IX
-------
FIGURES
Page
Chapter 5
FIGURE 5-1
FIGURE 5-2
FIGURE 5-3
FIGURE 5-4
FIGURE 5-5
FIGURE 5-6
FIGURE 5-7
Chapter 6
FIGURE 6-1
FIGURE 6-2
FIGURE 6-3
FIGURE 6-4
FIGURE 6-5
Chapter 7
FIGURE 7-1
SLUDGE LAGOON FAILURE ZONES
AND SAMPLING STATIONS
CORING APPARATUS
SLUDGE DEPTHS
LAGOON 1 PHYSICAL AND CHEMICAL
DEPTH PROFILE
LAGOON 2 PHYSICAL AND CHEMICAL
DEPTH PROFILE
IMPACT OF LAGOON SUPERNATANT
ON AMMONIA CONTENT OF TREATMENT
PLANT INFLUENT
AMMONIA REMOVAL AND RECOVERY
PROCESS (ARRP)
GROUND-WATER PIEZOMETRIC SURFACE
AND FLOW DIRECTIONS
ANNUAL TREATMENT PLANT SLUDGE
APPLICATION RATES FOR DIFFERENT
AVAILABLE NITROGEN REQUIREMENTS
ANNUAL LAGOON SLUDGE APPLICATION
RATES FOR DIFFERENT AVAILABLE
NITROGEN REQUIREMENTS
GENERAL SOIL MAP
LAND USE
ON-FARM LAGOON DESIGN
CONSIDERATIONS
5-3
5-5
5-8
5-11
5-12
5-19
5-21
6-5
6-16
6-17
6-34
6-35
7-13
x
-------
Chapter 7 (Continued)
FIGURE 7-2
FIGURE 7-3
Chapter 8
FIGURE 8-1
FIGURE 8-2
FIGURE 8-3
Chapter 9
FIGURE 9-1
Appendix A
FIGURE A-1
FIGURE A-2
FIGURE A-2
FIGURE A-4
FIGURE A-5
FIGURE A-6
Appendix D
FIGURE D-1
FLEXIBLE HOSE SLUDGE SUPPLY
SYSTEM WITH SUBSURFACE INJECTOR
SCHEMATIC DIAGRAM OF TRACTOR
SPREADER DEVICE
SLUDGE DISTRIBUTION FACILITIES
SITE PLAN
REUSE PROGRAM SITE PLAN
REUSE PROGRAM STAFF REQUIREMENTS
SLUDGE REUSE PROGRAM IMPLEMENTA-
TION SCHEDULE
LAGOON 1 CHEMICAL DEPTH PROFILE
LAGOON 1 CHEMICAL DEPTH PROFILE
LAGOON 1 CHEMICAL DEPTH PROFILE
LAGOON 1 CHEMICAL DEPTH PROFILE
LAGOON 1 CHEMICAL DEPTH PROFILE
LAGOON 1 CHEMICAL DEPTH PROFILE
MAP OF SLUDGE USER'S LAND
Page
7-18
7-23
8-10
8-11
8-16
9-11
A-1
A-2
A-3
A-4
A-5
A-6
D-4
-------
PHOTOGRAPHS
Page
Chapter
5 TYPICAL SLUDGE CORE 5-2
5 COLLECTING SAMPLE FROM PEAT SAMPLER 5-4
5 MUD CAT ON NINE SPRINGS LAGOON 5-17
7 LAGOON CLEAN-OUT OPERATION AND TRUCK-
LOADING FACILITY 7-10
7 HAND MOVEABLE BIG GUN SPRINKLER 7-15
7 PORTABLE SLUDGE PUMP 7-15
7 DEEP-SIX INJECTOR 7-17
7 ON-FARM LAGOON, SPRINKLER APPLICATION,
AND SOIL INJECTION 7-19
7 BIG WHEELS SLUDGE SPREADER TRUCK 7-20
7 TRUCK SPREADERS AND TANKER TRAILERS 7-21
7 TRACTOR SPREADER AND NURSE TANK SUPPLY 7-22
xn
-------
1.1 SCOPE OF STUDY
12 HISTORY OF SLUDGE DISPOSAL AT
NINE SPRINGS TREATMENT WORKS
1.3 PAST REPORTS ON SLUDGE DISPOSAL
INTRODUCTION
1
-------
Chapter 1
INTRODUCTION
This report is in partial fulfillment of an agreement dated
28 January 1975 between the Madison Metropolitan Sewerage
District (MMSD) and CH2M HILL to furnish engineering services
to MMSD for an Advanced Waste Treatment (AWT) Facilities
Plan and an Organic Solids (sludge) Reuse Program for the
Nine Springs Sewage Treatment Works. Described herein are
the investigation of alternatives and the recommended Sludge
Reuse Program. The AWT Facilities Plan by CH2M HILL is
reported separately. Another engineering consultant, O'Brien
and Gere, has been retained by MMSD to develop the long-term
wastewater discharge strategy. These studies are in compli-
ance with Wisconsin Pollutant Discharge Elimination System
(WPDES) Permit No. WI-0024597 received by MMSD on 27 September
1974. The permit requires completion of a facilities plan
prior to further work on advanced treatment, sludge disposal,
and final effluent disposal.
This report on sludge reuse precedes completion of the
discharge strategy and facilities plans so that the recom-
mended reuse plan can be more quickly implemented. Therefore,
certain estimates of the character and quantity of sludge to
be reused had to be made for this report. The reuse program
is flexible so that it can be modified upon completion of
new facilities or changes in the treatment plant operation
to allow for different organic solids character and quantity.
1.1 SCOPE OF STUDY
The work tasks required to prepare this report consisted of
the following:
• Review and analyze previous efforts related to
organic solids disposal.
• Determine present character and volume of sludge
and estimate future character and volume of sludge.
• Review local, state, and Federal regulations
regarding distribution and application of sludge
on land.
1-1
-------
• Perform a study of potential sludge application
sites including a soils survey, a ground-water
survey, and a review of current farming practices.
• Determine permissible organic solids loading
rates.
• Determine the probable extent of public and farm
community participation or concern in an agricul-
tural reuse program.
• Evaluate alternative reuse programs based on
potential sites for facilities and application,
ownership of sites, timing of organic solids
application, methods of distribution and applica-
tion, and management of application sites.
• Recommend a reuse program.
• Develop a public information and/or marketing
program.
• Outline a monitoring program which will assure the
success and safety of the reuse program.
1.2 HISTORY OF SLUDGE DISPOSAL AT NINE SPRINGS
TREATMENT WORKS
The Madison Metropolitan Sewerage District initiated the
practice of recycling sludge about 40 years ago. From the
early 1930's until World War II, the digested sludge produced
at the Nine Springs Sewage Treatment Works was dewatered on
sand drying beds and sold or given to the public for fertil-
izing lawns and gardens. This recycling program was stopped
at the beginning of World War II because the manpower required
to continually load and clean the drying beds was no longer
available.
In 1942 the District constructed a 45-acre sludge disposal
lagoon east of the Nine Springs Works. This disposal system
was relatively easy to maintain and resulted in low sludge
handling costs over the next 25 years. When the original
lagoon began approaching capacity in the 1960's, a second,
85-acre lagoon was constructed just east of the first lagoon.
The lagoon disposal system continued without problems until
April 1970 when a portion of the dike enclosing the second
lagoon broke. The resultant spill of approximately
85,000,000 gallons of lagoon supernatant into Nine Springs
1-2
-------
Creek was cited as the cause of a large fish kill. The
State of Wisconsin brought suit against the District for the
fish kill. The suit was settled when the District paid for
damages and entered into a stipulation assuring timely work
to achieve a more reliable sludge disposal method. The
District repaired the dike system and installed a pump and
pipeline to return supernatant from the east lagoon to the
plant for treatment. This was done to lower the water level
in the lagoons and to help prevent further dike failures.
The dikes have since been continuously maintained and raised
as needed.
In November 1973 another section of the second lagoon dike
began to fail. Extensive repair efforts prevented any large
supernatant spills. The decision was made in late December
1973 to discontinue using the second lagoon unless the first
lagoon filled to a level of potential failure. In order to
allow for continued use of the first lagoon, the District
began dredging sludge from it to make room for the
180,000 gallons of sludge discharged from the treatment
plant each day. This then began the existing system of
using the first lagoon for sludge storage and settling out
the solids. The supernatant is returned to the plant for
treatment and eventual discharge to Badfish Creek. The
solids are periodically dredged from the lagoon bottom and
hauled by truck to land of requesting farmers for recycle as
fertilizer and soil conditioner.
1.3 PAST REPORTS ON SLUDGE DISPOSAL
The 1970 lagoon dike failure prompted MMSD to seek more
reliable methods of sludge disposal. An investigation by
Warzyn Engineering and Service Company, Inc., showed that
the lagoon dikes were built on peat and silt with very
little bearing strength and would require extensive repair
to prevent further failures. In March 1971 Creeley and
Hansen Engineers finished a Report on Sewage Treatment-
Additions to the Nine Springs Sewage Treatment Works which
included possible courses of action for sludge handling and
disposal. The Wisconsin Department of Natural Resources
(DNR) reviewed the report and issued a pollution abatement
order which, among other things, required that MMSD provide
for the satisfactory disposal of sludge from the Nine Springs
Sewage Works and that the operation shall include provision
for the abandonment of the present method of disposal of
liquid sludge in the Nine Springs Marsh.
1-3
-------
In a report to DNR in January 1972 the District outlined
actions taken to arrive at an acceptable sludge disposal
solution and indicated the methods under consideration and
their associated costs. DNR replied that the following
sludge disposal methods would be acceptable: (a) spreading
of liquid digested sludge on farmland, (b) composting,
(c) vacuum filtration of digested sludge and disposal of
cake on land, and (d) vacuum filtration of undigested sludge
followed by incineration. During 1972 the District corre-
sponded with the City of Madison regarding composting the
City's solid waste with the District's sludge. Difficulty
in coordinating with the various organizations and
communities affected inhibited further investigation of this
alternative.
The District consulted the U. S. Soil Conservation Service
as to suitable areas for disposal of liquid sludge on lands
in Dane County. In July 1972 MMSD received a letter report
describing nine possible disposal sites. The nine sites
were selected on the basis of the soil's ability to filter
describing nine possible disposal sites. The nine sites
were selected on the basis of the soil's ability to filter
the leachate. In June 1973 MMSD retained Roy F. Weston,
Inc., Environmental Scientists and Engineers, to conduct a
study of appropriate methods for sludge handling and disposal.
The Weston report recommended that the District pursue
liquid digested sludge application on farmland as the method
of disposal. The District staff prepared an addendum to the
Weston report which examined several treatment and disposal
alternatives not considered in the Weston report. A more
detailed discussion of the alternatives considered in the
Creeley and Hansen and Weston reports is contained in Chapter 2,
Several proposals from commercial firms have been made to
MMSD for disposal of their sludge since the first dike break
in 1970. These include the Livingston Irrigation and Chemical
Company, BuhlerBros., Ltd., Browning-Ferris Industries,
Inc., and Enviro-Systems of Wisconsin. The proposals were
studied by the District and were either rejected or not
acted upon.
1-4
-------
2.1 GREELEY AND HANSEN REPORT
2.2 WESTON REPORT
2.3 MMSD ADDENDUM TO WESTON REPORT
2.4 MMSD DECISION
REVIEW OF SLUDGE
DISPOSAL ALTERNATIVES CONSIDERED
-------
Chapter 2
REVIEW OF SLUDGE DISPOSAL
ALTERNATIVES CONSIDERED
Alternative methods of sludge disposal have been studied in
detail by Greeley and Hansen, Engineers, and Roy F. Weston,
Inc., Environmental Scientists and Engineers.
2.1 GREELEY AND HANSEN REPORT
The Greeley and Hansen March 1971 Report on Sewage Treatment
Additions to the Nine Springs Sewage Treatment Works includes
a description of five alternative sludge handling and disposal
methods. The alternatives consist of the following: (A)
spread dried digested sludge on land; (B) incinerate digested
sludge; (C) incinerate raw sludge; (D) heat treat and land-
fill digested sludge; (E) apply liquid digested sludge to
land. Economic analysis of these five alternatives indicated
that Alternative E, liquid sludge application to land with
25-mile pipeline transport was the most cost effective. The
cost estimated for Alternative E treatment, disposal, and
transportation was about $23.00 per ton dry solids. The
costs for Alternative E with rail transportation was esti-
mated somewhat higher at about $30.00 per ton dry solids.
The estimated costs for the other alternatives including
25-mile truck transport, were as follows: (A) spread dried
digested sludge on land, $66.00 per ton dry solids; (B) incin-
erate digested sludge, $82 .00 per ton; (C) incinerate raw
sludge, $75.00 per ton; and (D) heat treat and landfill
digested sludge, $91.00 per dry ton, These costs were based
upon an Engineering News Record tENR) Cost Index of 1450 and
a sewage flow of 57 million gallons per day (mgd) .
2.2 WESTON REPORT
The Weston report. Nine Springs Sewage Treatment Works
Sludge Disposal Study, investigated several sludge disposal
methods. Subsurface placement disposal was rejected because
DNR stated that they would not approve of the method. The
alternative of continued lagoon disposal was eliminated
because of the recent lagoon dike failure and because it
would not receive support of public officials. Marketing
for land application of dried sludge in a form like Milorganite
was rejected because of lack of a suitable market.
2-1
-------
Incineration was also investigated in the Weston report.
Sludge dewatering, chemical addition, or use of supplemental
fuel to support combustion were considered necessary for
incineration. Mechanical dewatering was investigated, but
the moisture content of the cakes was so high that the heat
value of the cake was not adequate to support combustion.
Chemical additions, used to help achieve lower moisture in
mechanical dewatering, consumed so much heat in the recal-
cination process that again the sludge would not support
combustion. Sandbed drying and lagooning could be used to
dewater the sludge, but would not meet the requirement of
continuous sludge feed to an incinerator. It was therefore
determined that incineration could not be used without
supplemental fuel. The alternative of incineration was
abandoned because of the limited future fuel supply.
Three remaining alternatives for sludge disposal, sanitary
landfill, land application of liquid sludge, and land appli-
cation of compost, were found to be suitable and were analyzed
on the basis of costs. The estimated 1975 costs per ton dry
solids for a disposal rate of 10,676 tons per year were as
follows: Sanitary landfill system, $95.00; land application
of sludge-solid waste compost, $196.00; land application of
sludge-wood chip compost, $140,00; and land application of
liquid sludge system, $63.00. The alternative of land
application of liquid digested sludge was found to be most
economical and was recommended for implementation.
2.3 MMSD ADDENDUM TO WESTON REPORT
The MMSD staff prepared an addendum to the Weston report in
April 1974 which included additional sludge disposal alter-
natives. Seven alternatives were selected for further
study, three of which were eliminated. Alternatives 1B and
1C which included heat treatment of thickened raw sludge
followed by thickening, mechanical dewatering, and trucking
to land trench were both eliminated because of the poor
quality of thickener overflow and vacuum centrate following
the heat treatment process. Alternative 2B, anaerobic
digestion of sludge, followed by trucking to a lagoon and
land irrigation, was eliminated because of the high cost of
trucking the sludge.
Four remaining MMSD proposed alternatives and their estimated
costs per ton dry solids are as follows:
• Alternative 1A--Chemical conditioning of thickened
raw sludge followed by trucking to land trench,
$50.00.
2-2
-------
• Alternative 2A—Anaerobic digestion of thickened
raw sludge, followed by pipeline transport to a
lagoon and land irrigation, $41.00.
• Alternative 3A—Anaerobic digestion of thickened
raw sludge followed by chemical conditioning,
centrifugation, trucking to a mixing site, mixing
with milled refuse, and landfill disposal, $79.00.
• Alternative 3B—Anaerobic digestion of thickened
raw sludge followed by chemical conditioning,
centrifugation, trucking to disposal site, and
land spreading, $60.00.
Alternative 2A was found to be the least costly.
2.4 MMSD DECISION
The three aforementioned studies on methods of disposal of
sludge from the MMSD Nine Springs Sewage Treatment Works all
came to the same conclusion: Land application of liquid
digested sludge is the most economical and acceptable method
for sludge disposal. In June 1974 the MMSD Commission
resolved that liquid digested sludge from the Nine Springs
Treatment Works be handled through the process of application
on land. This report therefore deals solely with land
application as the disposal method. The other methods—
incineration, composting, mechanical dewatering—were found
to be technically unfeasible or less economical.
2-3
-------
3.1 GENERAL
3.2 EXISTING SYSTEMS
33 RESEARCH AND REPORTS
3.4 SUMMARY
LAND APPLICATION OF O
SLUDGE STATE OF THE ART O
-------
s:
Chapter 3
LAND APPLICATION OF SLUDGE
STATE OF THE ART
3.1 GENERAL
In reviewing what has been done throughout this country and
in Great Britain on the reuse of organic solids (sludge)
three basic levels of reuse came to light—fertilization,
high-rate fertilization and disposal. Table 3-1 illustrates
these three basic reuse levels.
The reuse of organic materials for "fertilization" as shown
on Table 3-1 utilizes low loading rates (less than 20 tons
dried material per acre per year) depending on sludge
characteristics, soil, and crop grown. The objective is the
maximization of crop production by full use of the nutrients
present in the organic materials. Almost any soil suitable
for high-rate agricultural production is suitable for this
type of operation. The key feature of this system is that a
balance between the nutrients added and the nutrients removed
with the crops is maintained. Only the amount of organic
material required to maximize crop production is applied.
METHOD
FERTILIZER
HIGH-RATE
FERTILIZER
DISPOSAL
(LANDFILL)
TABLE 3-1
THREE BASIC CATEGORIES FOR WASTE
ORGANICS APPLICATION TO LAND
MADISON METROPOLITAN SEWERAGE DISTRICT
LOADING RATES
MAXIMUM
ANNUAL ACCUMULATION
Less than 1-20 tons/ 100-1,000 tons/ac.
ac depending on
waste organics
characteristic, soil
and crop grown.
Less than 5 to more
than 75 tons/ac
5 to several
hundred tons/ac
prevent excess
accumulation of
heavy metals or
other pollutants
in soil
400-1,000 tons/ac.
to prevent toxir
accumulations of
pollutants in the
soil
Several hundred
to 1,000 or more
tons/ac.
OBJECTIVE
Maximize crop pro-
duction by use of
fertilizer value to
supply part or all
of primary and/or
micro nutrients.
Apply organics to
cropped soil Main-
tain crop while
maximizing organics
applications.
To dispose of
organics by incor-
poration m soil
A crop may or may
not be grown
between applications.
SUITABLE
SOILS
Any soil which is
suitable for high
agricultural produc-
tion
Generally fine-
textured soils with
a high capacity to
' adsorb or precipi-
tate large quantities
of heavy metals or
other pollutants.
Generally fine-
textured soils with
a high capacity to
adsorb or precipitate
large quantities of
heavy metals or
other pollutants
IMPACT ON
SOIL
Improves soil fertility
and organics improve
soil structure No
detrimental effects.
May reduce soil use-
fulness for some
crops or uses soil
that would probably
be improved at
lighter loadings
Accumulation of
pollutants in soil
must be monitored
Soil usefulness will
likely be greatly
reduced. Accumula-
tion of pollutants
in soil should be
monitored.
QUALITY
WATER
With a well-managed
system, there would
be no harmful effect
on ground water or
surface water.
Possibly would result
in excess nitrogen
which could be leach-
ed to ground water
Proper management
of surface runoff
would protect surface
waters
Excess nitrogen
could be leached to
ground water Proper
management would
minimize potential
for pollution from
other materials.
3-1
-------
The "high-rate fertilizer" system uses higher loading rates
(up to 75 tons per acre per year). The objective is to
maximize the amount of organic materials applied with crop
production secondary in importance. Soils suitable for this
type of operation should be fine textured with a high capac-
ity to absorb or precipitate large quantities of heavy
metals. Eventually, continued unbalanced applications of
organic materials may reduce the soil's usefulness to grow
certain crops because of accumulations of heavy metals or
salts. The application of the nitrogen contained in the
organic materials would not be balanced by crop removal or
natural denitrification, and accumulation of nitrogen in the
soil would probably occur. Nitrogen compounds could even-
tually reach the ground water or surface system if proper
precautions are not taken.
The third general method of operation involves "disposal" at
very high loading rates (up to several hundred tons of
organic materials applied per acre per year) . The objective
is to dispose of as much organic material as possible by
incorporation into the soil with little or no emphasis on
crop production. Fine textured soils will precipitate large
quantities of heavy metals or other pollutants and are
suitable for this type of operation. The end result of
continued operation using the "disposal" method is the
potential impairment of the soil due to accumulation of
salts, heavy metals, and nitrates in the soil. Leaching of
nitrates, salts, and heavy metals from the soil into the
ground water or carrying of these materials into the surface
water regime are a potential hazard that must be designed
for.
3.2 EXISTING SYSTEMS
This review of the "State of the Art" was not intended to be
all inclusive, for to do so would require a voluminous
compilation of material. Pertinent examples of the general
types of systems presently in operation are presented.
Metropolitan Sanitary District of Greater Chicago (MSD)
The Metropolitan Sanitary District of Greater Chicago (MSD)
operates two organic solids sites utilizing land disposal
and/or incorporation techniques. At Arcola, Illinois, a
subcontracted system is operated by SEMCO (Soil Enrichment
Materials Company) . In Fulton County, Illinois, MSD oper-
ates an ambitious reclamation project to reclaim abandoned
strip mined land for agricultural production.
3-2
-------
SEMCO Project-Arcola. SEMCO (Soil Enrichment Materials
Company) is under contract with MSD to clean out several of
the District's existing sludge storage lagoons. The State
of Illinois Environmental Protection Agency has jurisdiction
over the operation and has issued a permit allowing appli-
cation of 150 dry tons of organic material per acre per year
to the land.
For several years up through 1974, SEMCO used about 300 acres
of owned and leased land for organic solids application. In
1973, they grew corn on 34 acres. The remainder of the site
was used solely for application of organics with no cropping.
In 1974, they grew corn and soybeans on about half of the
site and applied organics on the remaining half.
SEMCO has recently started selling the organics to farmers
and hauling it to them in trucks which also spread the
material. This method was begun because the site at Arcola
could not be enlarged.
The organic materials were incorporated into the top 14 inches
of the soil and spread by a tractor drawing an incorporation
mechanism. There had been public objections to application
of the organics by sprinkler irrigation because of wind
carry of the spray and odor problems. Because of public
objections, subsurface application has become the dominant
method of application.
The Illinois EPA has required construction of a berm around
the field to provide protection from the 100-year flood.
Runoff from precipitation and snowmelt is allowed to collect
behind the berm and stand for evaporation and percolation.
Because of the high application rates on the Arcola site and
the lack of continuous cropping of the majority of the area,
this site could be classified as a "disposal" site. Continued
monitoring of heavy metals buildup, nitrogen, phosphorus,
and coliform counts are presently being undertaken on the
Arcola site. As operating experience is obtained, these
data will be useful in judging the potential for pollution
of the ground water and the surrounding environment from
this type operation. The effects of the SEMCO operation on
the environment outside of the site appears to be minimal.
Fulton County Site. The Fulton County project site is owned
and operated by the Metropolitan Sanitary District of Greater
Chicago. The site is an abandoned strip mine encompassing
almost 750 acres. It is necessary to note that all this
3-3
-------
land was acquired without the need to obtain a conditional
land-use permit. The obtaining of such permits can become a
major political stumbling block to the implementation of
organic solids systems. Fulton County had no solids waste
ordinance at the time of land acquisition. They now have
such an ordinance along with all the traditional land-use
restrictions machinery and are currently negotiating with
the District on the location of additional storage basins.
The operation begins by barging the liquid organic material
200 miles down the Illinois River from the treatment plant
to the unloading docks in Fulton County. From there, it is
pumped overland about 11 miles through a pipeline to the
project site near Canton, Illinois, where it is stored in
four large lagoons. The total capacity of these lagoons is
approximately 8 million cubic yards. The lagoons encompass
an area of 260 acres at an average depth of 32 feet.
From the lagoons, the organic material is distributed to the
various fields through an overland piping system. In the
past, the material was applied to land using mainly self-
propelled big gun sprinklers. Presently, the main method of
sludge application is by tractor-drawn moldboard or chisel
plows. These soil incorporation systems are fed
3.5-4.0 percent solids content sludge by a flexible hose
which is dragged behind the plow. Sprinkler application is
now used only on certain sites which have adequate buffer
areas.
The surface runoff from the site is collected, and if not
detrimental to the receiving stream, it is discharged. If
the runoff is found to be detrimental, it is reapplied to
the fields.
The organic materials are spread by the Sanitary District
personnel as previously described. The farming operations
are all accomplished by contract. The contracted farmer
plants, cultivates, applies herbicides, and harvests and
crops for a price determined through competitive bidding.
The crop belongs to the District. Bidding interest has been
low, but the MSD personnel indicated that they have been
able to count on at least two bidders for each contract.
The cost of the farming operations appears to be about
double the going rate in the area. The reason is believed
to be the presence of the contract document with its long
list of legalities and specifications. Despite this markup,
the value of the crop has been paying for the farming opera-
tions.
3-4
-------
The Fulton County project currently has a permit to apply
75 tons of dry organics per acre for the first year, 60 tons
per acre the second year, and so on down to 20 tons per acre
during the fifth year. After this period, the permit will
be reviewed. To this date, they have only been able to
apply 5 tons per acre due to equipment limitations. They
will apply heavier loadings when they are capable.
The most significant observation made during our visits to
the Fulton County operation was the apparent lack of concern
over what we have come to consider in our studies as heavy
loadings. The crop grown on the project site is corn, and
only the grain portion of the corn is removed from the
field. The stalk and all the other foliage are left in the
field and thus the nitrogen contained therein is recycled
back to the soil. The net removal of nitrogen from the site
is much less than the amount applied each year.
The Fulton County operation can be classified as a "high-
rate fertilizer" system. The main objective is to maximize
organics application with the cropping of the site being
somewhat secondary to this end. MSD has recently come under
pressure from the U.S. EPA to change this operation because
of odor problems.
West Hertfordshire Main Drainage Authority, Great Britain
The West Hertfordshire Main Drainage Authority in Rickmans-
worth, Great Britain (HERTS) was visited to determine how
their program, which has been widely publicized by the EPA,
has actually operated.
The HERTS treatment works serves a total population of
550,000 plus several industries which produce a waste equiva-
lent to about 700,000 people. Total flow of the plant is
about 35 mgd (US). The plant provides secondary treatment
utilizing the activated sludge process. Waste activated
sludge and primary sludge are anaerobically digested and
hauled as a liquid to consenting farmers. They have more
requests for the organic materials than they can satisfy.
Several years ago, the HERTS Authority purchased 1,200 acres
of land for the purpose of "demonstrating the value of the
sludge as a fertilizer." The land was operated as a farm,
but the farmers never really accepted the system. They
viewed it as a disposal operation and would not accept the
use of the organic materials on their private farmlands.
3-5
-------
About 6 years ago, the Authority hired a marketing manager
whose job was to develop a market for organic materials. To
accomplish this task, he made several major changes in the
Authority's operation. The changes made were all in the
area of improving public relations. The Drainage Authority's
management acknowledges these changes as the key element to
their present success.
The changes made in the Drainage Authority's operation were
as follows:
1. The organic materials were given a name. The
name, "HYDIG," was established and enabled the
Authority to use a name other than "sewage sludge"
or "waste organic materials" in all of their
literature. Everyone in the vicinity of the
Authority's operation knows what HYDIG is, but
they are not reminded so blatantly that the material
is "sewage sludge." HYDIG is a much less descrip-
tive and more acceptable name for the product.
2. The public and the farmers were told explicitly
what HYDIG is. HERTS has published a pamphlet
describing in very basic language the operation of
the treatment plant, the origin and treatment of
HYDIG, the fertilizer value of HYDIG, and some
documentation on its benefit as a fertilizer.
3. A strong monitoring program was instituted. A
policy was developed by which organics would not
be applied to any land until samples of soil were
analyzed for heavy metals content. Once the soil
data are recorded, organics are applied according
to a predetermined program. A sample of the
organics is also analyzed prior to application to
the farmer's land.
The basis of control is the "zinc equivalent"
wherein the metals concentrations are related by
their relative toxicity to the toxicity of zinc.
The British admit that they are not sure they are
recording the correct data or if the data will be
of use in the future. They are sure, however,
that it is important to the farmer to know that
someone is watching over his land to make sure it
is not damaged.
3-6
-------
4. The farmer is given the quantity of material that
he wants when he wants it and where he wants it.
The British have gone out of their way to please
the farmer. In addition to trucking and spreading
the materials, they also provide free spraying, if
desired. Portable pumps and irrigation equipment
are used during the winter when the fields are too
wet to get a truck on the land.
5. The image of the truck driver was changed. The
truck drivers are first and foremost the ambass-
adors of the Authority. The public and farmers
see more of the drivers than any other individuals.
The drivers travel about 100-120 miles per day in
about eight trips. They spread organics, lay
pipe, or do anything else to speed up the operation.
They take samples as required and also keep a log
of all activities. They also must keep their
trucks clean. It was noted that it takes a great
deal of supervision to maintain a crew of drivers
that will adhere to this code of conduct. While
good conduct was lavishly recognized, bad conduct
resulted in immediate dismissal.
With the foregoing public relations program, the Authority
has been able to dispose of their entire supply of organic
materials on public farmlands.
The HERTS Authority currently operates a fleet of 22 tank
trucks ranging in size from 1,200 U. S. gallons to 6,000
U. S. gallons. They also have two portable pumps and asso-
ciated irrigation equipment. In the summer, about 85 percent
of the organics is truck spread and 15 percent is spray
irrigated. In the winter, about 85 percent is spray irrigated
and 15 percent is truck spread. They currently deliver to
about 70 farmers who own an average of 100 acres each, or a
total of 7,000 acres. Standard application rates are about
12,000 U. S. gallons of 4 percent organic material per acre
per year. This is quivalent to a dry solids loading of
about 2.0 tons per acre per year. This is considerably
lower than the 20-75-ton loading at the Chicago Fulton
County site. The HERTS Authority now puts organics on their
own land only for the purpose of maintaining current research
programs.
The cost to the Authority for utilizing their organic mater-
ials in this manner is about $3.25 per ton of dry solids.
This includes all costs from the time the material leaves
3-7
-------
the secondary digester until it is on the fields (including
the cost of management) . This compares to $12 . 50 per ton
for estuarine or ocean disposal, which is the major means of
disposal in Great Britain.
The HERTS application is a most notable example of the
"fertilizer" category of organics application shown in
Table 3-1. The organic material is utilized mainly as a
source of fertilizer for growing crops, and the growth of
crops is optimized by the individual farmers. The disposal
of organic material by the farmers is a secondary considera-
tion with maximizing of crop production being primary in
their minds.
Los Angeles County Sanitary District Composting System
Representatives of CH2M HILL visited the Los Angeles County
Joint Wastewater Treatment Facility in Willmington, California,
where air drying and composting of organic materials is
presently practiced.
The plant is a 350-mgd primary plant with single-stage
anaerobic digestion. No solids-liquid separation takes
place in the digesters, and the digested sludge is centri-
fuged in solid bowl centrifuges. Centrifuged sludge at
approximately 70 percent moisture is applied to the com-
posting system.
Approximately 100-120 tons of dry solids per day are com-
posted by constant turning in long windrows approximately
4.5 feet high. The final product is approximately 30 per-
cent moisture. Temperatures of 140°-150°F are reached
within the windrow during the composting and curing operation
which takes approximately 20 days in the summer and 40 days
in the winter.
The composting operation is extremely dependent on having
dry weather for successful operation. If prolonged periods
of rainfall occur, the entire composting operation must be
stopped and the organic material removed and buried.
During such periods, strong odors can occur. During normal
operation, the process is relatively odor free.
The composted end product is sold to a fertilizer company
located on county land adjacent to the composting operation.
The fertilizer company bags the compost without additives
and sells it for home garden use. They are able to market
all of the composted organic material that is produced by
this plant and are currently allocating it to selected
customers.
3-i
-------
City of Boulder, Colorado
James L. Smith, Associate Professor of Agricultural Engi-
neering at the Colorado State University in Fort Collins,
Colorado, has been working with the City of Boulder, Colorado,
to develop a system of subsurface injection for their organic
materials. The subsurface injection system developed by
Smith requires relative low power inputs and mixes the
sludge with the top layers of the soil (at depths as shallow
as 3-5 inches). With this type of injection plow,
1,000-1,500 gallons per minute of 4-5 percent solid material
can be injected below the surface of the soil.
One significant result achieved by Smith's work is the fact
that the injector can be used to achieve high loading rates
at low cost. Several of his test plots have received a
total of nine injections of organic material; an application
rate of 280,000 gallons per acre. The average solids con-
tent of this material was 3.8 percent and resulted in a
loading rate of 45 dry tons per acre. Most of the plots
were injected weekly during October and November.
Smith anticipates that because of the high performance
characteristics of this machine, it would be possible to
inject organic material during wet weather or with snow on
the ground and still obtain satisfactory results. The
injector has been operated successfully when the ground was
frozen 2 inches deep.
>
At Boulder, the organic material is delivered to the operating
tractor and plow through a buried pipeline to various connec-
tion points throughout the injection field. A 660-foot
6-inch-diameter rubber hose connects the plow to the distri-
bution points.
Metropolitan Denver Sewage District No. 1
In early 1971, the Metropolitan Denver Sewage Disposal
District No. 1 made a commitment tp develop a long-term
beneficial sludge reuse system to replace an interim sludge
recycle system at the Lowry Bombing Range. An investigation
of alternative systems indicated that agricultural reuse of
anaerobically digested wastewater treatment plant sludge is
the most economically and environmentally desirable solids
handling system for the District. Digested sludge used as
fertilizer has shown strong indications of being a valuable
resource. In a preliminary marketing effort, the District
has already located some potential users for its digested
sludge.
3-9
-------
Design has now begun on an agricultural reuse system which
is expected to begin operation in early 1977. The proposed
site of this new agricultural reuse system will be located
approximately 25 miles east of the Central Plant and will
initially encompass 2,000 acres. The site will serve as a
sludge drying and distribution center. Sludge treatment
will be accomplished by anaerobic digestion at the Central
Plant in Commerce City. The liquid sludge will then be
delivered from the plant to the distribution site through a
system of force mains and a booster pumping station. The
drying and distribution site will include approximately
600 acres of drying basins for open air drying of the sludge,
a storage area for stockpiling the dried material prior to
distribution to the users, an area of subsurface injection
of the sludge, demonstration plots, and miscellaneous site
facilities necessary for operation and maintenance. The
sludge material will be available for agricultural reuse in
both dry and liquid form. The dried sludge produced by the
open air drying process will be stored at the distribution
center for marketing. The liquid sludge will be distributed
to the farmers from the Central Plant, the booster pump
station, or the distribution center.
City of Salem, Oregon
A fertilizer rate reuse program has recently been started at
Salem, Oregon. This program was patterned after the HYDIC
system used in England. The sludge has been given a trade
name, BIOCRO, a brochure has been prepared and distributed
which describes BIOCRO and the reuse program, and a public
relations manager has been appointed. The City has been
truck hauling and applying 45,000-60,000 gallons of sludge
to farmland each day. The program has been an immediate
success with more than 20 farmers requesting sludge for
their land.
Other Locations
Table 3-2 briefly describes several other selected sludge
reuse programs.
3-10
-------
TABLE 3-2
OTHER SLUDGE REUSE PROGRAMS
MADISON METROPOLITAN SEWERAGE DISTRICT
LOCATION METHODS
Springfield. Illinois Sprinkler application on 66 acres Began in 1965
Ottawa, Illinois Surface irrigation on 37 acres Reclamation
of silica sand site
Shawnee National Forest, Land application on 190 acres Reclamation
Illinois of barren strip-mined land
Blue Plains, D C Plow or disk sludge into soil Trench in up to
500 tons per acre Presently 240 wet tons per
day are being processed into dried pellitized
fertilizer for sale. Land application for
reclamation, soil conditioner, or fertilizer at various
places using different methods since 1938
San Diego, California Reclamation of Mission Bay Park began in 1951
St Mary's, Pennsylvania Hauled in 1,500 gallon capacity trucks, applied
with portable irrigation system Used, on farmland.
Piqua, Ohio Hauled and applied on 380 acres with 5,000
gallon capacity tanker
Montgomery County, Ohio Liquid sludge hauled and applied with 3300
and 6,300 gallon capacity trucks. Filter cake
also used Sludge applied on county and private farms
Kankankee, Illinois Apply liquid sludge on 8,000 acre ranch
Began in 1965
England About 40% of municipal treatment works
recycle sludge to land
Marshall, Missouri Switched from drying beds to liquid sludge
recycle in early 1950's Used on farmland.
Milwaukee, Wisconsin Sludge is mechanically dried, bagged, and
marketed as fertilizer and soil conditioner
Marketed under trade name of "Mitorganite"
Grand Rapids, Michigan Sludge is mechanically dried and marketed
as a fertilizer and soil conditioner
Marketed under trade name of "Raptdgro"
Operated since 1932.
28 Cities in Southeast Recycled on land as soil conditioner and
fertilizer in towns in Alabama, Arkansas,
Florida, Kentucky, South Carolina, and
Tennessee.
3.3 RESEARCH AND REPORTS
University of Wisconsin Research
The College of Agricultural and Life Sciences, University of
Wisconsin, Madison, has been actively involved in research
on land application of sludges for several years. Their
research has shown that rye, corn, and sorghum-sudan yields
increased with moderate sludge applications (Kelling, et al,
1974) . Up to 20 cm of liquid digested sewage sludge were
applied with no detrimental effect on yields. They did
notice that where sludge or water is spread by tank truck on
established alfalfa, crown survival through the winter and
yields were markedly reduced. They also found that liquid
sludge provides residual fertility and its greatest benefit
may be improvement of the long-term fertility status of
soils.
3-11
-------
Research on phytotoxic effects of heavy metals in sludge was
reported by Cunningham in 1974. This, as most of the research
reported on by the University of Wisconsin, was performed at
Arlington and Janesville, Wisconsin. These studies indi-
cated that the cadmium application should be limited to
2 pounds Cd per acre each year and 20 pounds Cd per acre
over the life of the site. Ryan and others in 1973 and 1975
reported on nitrogen transformations and availability in
sludge-amended soils.
Other Major Reports
The current sludge handling technology is covered in many
publications. Among the more recent are the Proceedings of
the Second National Conference on Municipal Sludge Manage-
ment and Disposal which was held in August 1975, and the
Process Design Manual for Sewage Sludge Treatment and Disposal
(EPA, 1974). Burd in 1968 reported on the status of the
sludge handling art.
3.4 SUMMARY
Several important principles can be derived from the "State
of the Art" review reported herein. If a true recycle
system is to be established and the organic materials truly
utilized for beneficial purposes, then it becomes evident
that cooperation of the local farming community is essential.
Experience of the HERTS Authority in Great Britain emphasizes
that the importance of a well-managed distribution operation
cannot be overstated.
3-12
-------
4.1 CHARACTER OF SLUDGE PRESENTLY PRODUCED
4.2 CHARACTER OF SLUDGE PRODUCED
IN THE FUTURE
TREATMENT PLANT
SLUDGE CHARACTERIZATION
-------
Chapter 4
TREATMENT PLANT SLUDGE CHARACTERIZATION
The Nine Springs Sewage Treatment Works' sludge character
and quantity were required for the basis of the land applica-
tion rates. The existing sludge characteristics were deter-
mined by sampling and analyzing the digested sludge produced
by the Nine Springs Works. The future sludge character may
change due to changes in the sewage input or because of
changes in the operation or equipment of the treatment
works. Since this study precedes the final results of the
advanced waste treatment study, the expected changes in the
sludge character and volume had to be estimated for the
treatment alternatives considered.
4.1 CHARACTER OF SLUDGE PRESENTLY PRODUCED
The character of the sludge produced under the existing
conditions was determined by a sampling and chemical analysis
program and by comparison to data supplied by MMSD.
Sampling and Analysis Procedures
Analyses were performed on grab samples collected at the
digested sludge inlet pipe to the small lagoon.
The sampling procedures and analytical tests performed on
both the treatment plant sludge and lagoon deposit samples
collected during the study were in accordance with the
following publications:
• EPA: Methods for Chemical Analysis of Water and
Wastes (1974) .
• APHA, AWWA, WPCF: Standard Methods (1971).
• Roberts, S., Vodraska, R. V., Kauffman, M. D., and
Gardner, E. H.: Methods of Soil Analysis Used in
the Soil Testing Laboratory at Oregon State Univer-
sity (Special Report No. 321, April 1971). Agri-
cultural Experiment Station, Oregon State Univer-
sity, Corvallis.
4-1
-------
• EPA: Great Lakes Region Committee on Analytical
Methods: Chemistry Laboratory Manual—Bottom
Sediments (December 1969).
The treatment plant sludge samples were analyzed for the
following constituents: total solids, total volatile solids,
total soluble salts, pH, potassium, iron, zinc, copper,
titanium, lead, barium, chromium, manganese, nickel, tin,
cadmium, molybdenum, cobalt, aluminum, arsenic, boron,
selenium, mercury, sulfate, alkalinity, calcium, magnesium,
total Kjeldahl nitrogen, ammonia nitrogen, and total phospho-
rus.
Results of Analysis
The results of the analysis performed for this study and in
the recent past by Warf Institute for MMSD are shown in
Table 4-1. Because there was some question about the validity
of the analysis for nitrogen, extra analyses were performed
by CH2M HILL and MMSD. These results are shown with results
of analysis by the University of Wisconsin Soils Laboratory
in Table 4-2.
TABLE 4-1
CHARACTERIZATION OF TREATMENT PLANT ORGANIC SOLIDS
MADISON METROPOLITAN SEWERAGE DISTRICT
PARAMETER
Total Solids, %131 2.3 2.2
Total Volatile Solids, %<3> 1.6 1.6
Total Soluble Salts (EC), jimhos/cm 6.380 7.220
pH 8.11 8.12
Potassium, mg/kg 9,100 9,100
Iron, mo/kg 10.800 6,800
Zinc, mg/kg 1,600 2,200
Copper, mg/kg 500 570
Titanium, mg/kg <90 <90
Lead, mg/kg 640 380
Barium, mg/kg 1,820 1,000
Chromium* mg/kg 290 100
Manganese, mg/kg 200 170
Nickel, mg/kg 270 60
Tin, mg/kg <10 <10
Cadmium, mg/kg <40 160
Molybdenum, mg/kg < 10 < 10
Cobalt, mg/kg 40 < 20
Aluminum, mg/kg 2.640 3.100
Arsenic, mg/kg 14 < 14
Boron (hot water soluble), mg/kg 4.0 394
Selenium, mg/kg <4 < 4
Mercury, mg/kg 6.2 6.5
SO4-S (soluble), mg/kg 470 200
Alkalinity as CaC03 pH 4.5, mg/kg 5,800 6,100
Alkalinity as CaCOj pH 4.2, mg/kg 6,300 6,600
Calcium, mg/kg 13.400 62,300
Magnesium, mg/kg 6,600 7,400
Total Phosphorus, mg/kg 6,000 9,100
CH2M HILL WARF INSTITUTE
2-21-75 3-10-75 4-11-75 4-30-74 5-22-74 5-31-74 6-6-74 6-14-74
AVERAGE
TYPICAL
DIGESTED
SLUDGES12
2.5 2.92 2.41 2.21 2.28 1.88
1.6
7,840
8.11
4,820
8.950
1.910 2,192 2,448 3,032 2,877 2,712
505
175 188 245 177 246 234
600
312
198
50.5 55 45.6 54.3 61.4 53.2
2.34
1.6
7,150
8.11
7,670
8.850
2,370
525
<90
286
1,140
234
189
81
4 -
12,000 -
8,000 -
490 -
140 -
40 -
530 -
50 -
180 -
15 -
6
19,000
78.00O
12,200
10,000
4,600
1,340
32,000
1,130
1,700
60.3 37.7 62.2 63.3 87.7
69
500
4.8
77,900
12,900
26,800
10.3
10.7
17.2
19.3
17.6
73
30
2.870
14
300
11.6
336
5.950
6.450
51.200
8,970
13,970
3,600
150
06
400
12,000
750
31
42.000 -180.000
8.000 - 12,000
27.000 - 61,000
ID Results are shown on dry weight basis, except as noted,
for various sampling dates.
(2) As reported by Konrad and Klemert.
(3) Percent of sample volume.
4-2
-------
TABLE 4-2
SUMMARY OF NITROGEN ANALYSIS111 OF MMSO DIGESTED SLUDGE
MADISON METROPOLITAN SEWERAGE DISTRICT
DATE
5-16-74
5-23-74
5-30-74
6-0674
6-20-74
6-27-74
2-21-75
3-10-75
4-11-75
6-29-75
6-03-75
ANALYZED
BY
U of W Soils Lab
U of W Soils Lab
U of W Soils Lab
U of W Soils Lab
U of W Soils Lab
U of W Soils Lab
CH2M HILL
CH2M HILL
CH2M HILL
CH2M HILL
MMSD
TOTAL
NITROGEN
l%]
82
9 1
93
96
90
93
11.4
14.8
123
12 1
10.4
AMMONIA
(%]
39
48
49
52
4.3
46
6.9
79
6.6
6.3
57
ORGANIC
(%>
43'21
43'21
44121
4.5 '2I
47'21
48121
45
6.9
57
5.8
47
Average MMSD Digested Sludge 10.5 5.5 , 50
Average MMSD Lagoon Sludge 59 12 47
Typical Digested Sludge 50 1.6 34
(1) Unless otherwise noted all samples were analyzed on
a wet weight and reported on dry weight basis.
(2) These samples were oven dried before analysis for
total nitrogen. Therefore the results art only an
estimate of the organic nitrogen. The total
nitrogen content is the sum of the ammonia plus
an estimate of the organic.
The sludge analysis also indicated a high level of cadmium.
Therefore, in an attempt to find major cadmium sources,
effluent samples from five service area industries, Ray-O-
Vac, Ohio Medical Labs, Kipp Corporation, Mautz Paint
Company, and Northern Plating, were collected and analyzed.
This survey did not find any significant single source of
cadmium. Of an estimated cadmium inflow to the plant of
about 2.9 pounds per day, less than 0.15 pound per day could
be attributed to the five sampled industries.
Discussion of Results
Most of the sludge constituents, with the exception of
ammonia nitrogen and solids content, are within or near the
range of values for typical digested sludges. The high
ammonia nitrogen may be creating a problem of ammonia tox-
icity in the digesters. Under normal operating conditions,
which should be achieved in future modifications to the
treatment plant, the ammonia nitrogen content is expected to
be nearer to the typical 1.6 percent. Lagoon aging of the
sludge for a few months has also been shown to be effective
in reducing the nitrogen content to normal levels. The high
nitrogen content of the sludge, while being a benefit to the
farmer, creates a problem for the District in that more
farmland would be required for sludge application.
4-3
-------
The solids content is lower than typical for digested sewage
sludge. This low solids content results in about twice as
much liquid to be handled as would be required with a
typical 4- to 6-percent solids sludge.
The cadmium to zinc ratio of the treatment plant sludge
averages 3.1 percent. This may present a problem for land
application of the sludge because of a possible health
hazard. This problem is discussed further in Chapter 6.
Possible sources of the relatively high cadmium content
include the electroplating industries, pigments and chemi-
cals, alloys, and automobile radiators and batteries. The
District should perform an industrial waste survey to identify
the point sources and require that cadmium be removed before
discharging to sewers.
4.2 CHARACTER OF SLUDGE PRODUCED IN THE FUTURE
The character of the sludge produced in the future will
depend on the discharge strategy ultimately selected for the
project. Several discharge strategies have been considered
for this project which require a wide range of effluent
qualities and, therefore, a wide range of degrees of treat-
ment. Since the quality and quantity of sludge produced is
dependent on the degree of treatment, it is necessary to
define what levels of treatment are being considered so that
the impact on the reuse program can be assessed.
At this time, several discharge strategy alternatives have
been eliminated. Those remaining for detailed study require
the following effluent qualities or degrees of treatment.
• Effluent I: Less than 30 mg/l of BOD and suspended
solids; less than 2.0 mg/l ammonia nitrogen.
« Effluent II: Less than 10 mg/l of BOD and suspended
solids; less than 0.2 mg/l of ammonia nitrogen.
• Effluent III {for industrial reuse): Less than
100 mg/l of total hardness; less than 1,000 mg/l
of total dissolved solids; less than 0.2 mg/l
ammonia nitrogen.
The qualities required for Effluents I and II can be accom-
plished with conventional biological treatment processes.
The quality required for Effluent III will require a lime
softening treatment of the effluent from a biological treat-
ment process. A discussion follows on how these effluent
4-4
-------
quality requirements will affect the future quality and
quantity of sludge produced at the Nine Springs Works.
Quality of Sludge
Organic Sludges. The quality of the organic sludges is
expected to improve with the anticipated modifications and
expansions required to meet the effluent qualities under
consideration. The current high ammonia content and low
solids concentration may be improved by a modification of
the digester operation. This is currently under study as a
part of the AWT study. If this study fails to find an
acceptable solution, another solution would be to age the
sludge by lagoon storage. Aging the sludge would accomplish
two things; first, a portion of the ammonia will be lost by
volatilization and second, the sludge will go through a
natural freeze-thaw cycle which has proven to be effective
in improving the settleability and dewaterability of the
sludge.
Lime Softening Sludges. As stated earlier. Effluent III
will require lime softening of a high quality effluent to
make it acceptable for industrial reuse. This process will
produce large quantities of lime sludge in addition to the
organic sludges if this effluent is required. We again will
recommend that these sludges be handled separately. Depending
on the quality of the lime sludge, it may be suitable for
land application to maintain a proper pH in the soil. If
the lime sludge is of poor quality, we will recommend
landfill as the ultimate method of disposal. In the event
industrial reuse is selected as the recommended discharge
strategy, we will investigate the ultimate disposal methods
in more detail.
Quantity of Sludge
The quantity of organic sludges is, for most cases, expected
to increase with the implementation of the proposed modi-
fications and expansions to the Nine Springs Sewage Treatment
Works.
The 1974 level of sludge production was estimated, based
upon MMSD data, to be about 5,350 tons dry solids per year.
This is expected to increase in proportion to the volume of
flow treated until 1977 when the Fifth Addition goes on
line. The sludge production is then expected to increase
markedly to about 6,000 tons dry solids per year due to more
effective BOD removal. The sludge production is again
4-5
-------
expected to increase in direct proportion to the volume
treated until 1981 when the advanced waste treatment (AWT)
facilities are expected to go on line. The sludge production
with AWT will depend upon the level of treatment provided
and the treatment process selected.
There are currently several processes under consideration to
produce the levels of treatment required. One of these
processes will eliminate the need to digest and recycle
secondary waste activated sludge. It is a biophysical
treatment process* which utilizes activated carbon in the
aeration basin to absorb nonbiodegradable organics. During
the process of regenerating the spent carbon, the waste
activated sludge is converted (destroyed) to an inert ash.
This ash can then be handled separately and placed in a
landfill or it may be returned to the head of the plant and
handled with the primary sludge. If this process is selected,
there will be a significant reduction of organic sludge to
handle as there will be no waste secondary sludge. Only
primary sludge would then be available for anaerobic diges-
tion and land application.
Implications of a Future Phosphorus Removal Requirement
At the present time, the discharge strategies being con-
sidered in detail do not require phosphorus removal. However,
in the event future effluent quality requirements demand
phosphorus removal, we would recommend that a chemical
treatment system be employed. The effect of a chemical
phosphorus removal system on the quantity and quality of
sludge produced will depend upon the specific process employed
which, in turn, will depend upon the phosphorus removal
requirement.
The two most common phosphorus removal systems employed
today are:
1. Addition of alum or ferric chloride to the acti-
vated sludge aeration basins and
2. Addition of alum, ferric chloride, or lime in a
separate tertiary treatment system.
At the present time, these systems also appear to be the
most promising alternatives for future phosphorus removal at
Nine Springs.
*Developed and marketed by Zimpro, Inc.
4-6
-------
The addition of alum or ferric chloride to the activated
sludge system will result in the production of a combined
biological-chemical sludge. Experience with anaerobic
digestion of combined biological-chemical sludges has shown
that the digestion process is generally not impaired.
Achievement of 80-90 percent phosphorus removal at the Nine
Springs plant, however, would increase the quantity of
digested solids requiring disposal by 50 percent or more.
More important, the quality of organic solids would be
severely impaired by the presence of a high concentration of
aluminum or iron. Based upon irrigation water quality
criteria discussed in Section 6.3, these biological-chemical
sludges would not be suitable for land application.
Tertiary chemical treatment for phosphorus removal with
alum, ferric chloride, or lime would result in production of
a chemical sludge. We would recommend that such purely
chemical sludges be handled separately from the organic
solids. As stated earlier, lime sludge may be suitable for
land application to acid soils to maintain a proper soil pH.
Chemical sludge resulting from the addition of alum or
ferric chloride would have few beneficial qualities for land
application. Consequently, dewatering and landfill would be
appropriate for alum and iron sludges and for lime sludge
which could not be land applied.
Summary
TABLE 4-3
SUMMARY OF EXPECTED TREATMENT PLANT
ORGANIC SOLIDS QUALITY
MADISON METROPOLITAN SEWERAGE DISTRICT
PARAMETER111
Total Solids, %
Nitrogen. %
Phosphorus, mg/kg
Potassium, mg/kg
Cadmium, mg/kg
Zinc, mg/kg
Copper, mg/kg
Nickel, mg/kg
EXISTING
2.3
10.5
13,970
7,670
73
2,370
525
81
5TH ADDITION
ON LINE
1977
23
10.5
13,970
7,670
50 131
2,370
525
81
AWT
ON LINE
1981
5<21
5(2>
13,970
7,670
20 13)
2,370
525
81
Tables 4-3 and 4-4
summarize the qua-
lity and quantity of
the treatment plant
sludge (organic
solids) to be used
for the remainder of
the report.
(1) All results, except total solids are reported
on dry weight basis.
(2) Improved quality expected due to
modifications in plant operation
(3) Improved quality expected due to
source removal program
4-7
-------
TABLE 4-4
SUMMARY OF EXPECTED TREATMENT PLANT
ORGANIC SOLIDS QUANTITY")
MADISON METROPOLITAN SEWERAGE DISTRICT
LEVEL I LEVEL H LEVEL II LEVEL III
YEAR 30/30(21 10/10 10/10 10/10
1981 5,870 6,730 2,890 6,730
+Lime Sludge
1990 6,560 7,500 3.230 7.500
+Lime Sludge
2000 7,460 8,520 3.660 8,520
+Lime Sludge
(1) Tons of dry solids per year.
(2| Indicates an effluent with 30 mg/l of BOD and
30 mg/l of suspended solids.
The solids content is expected to be increased to about
5 percent and the high nitrogen content is expected to be
reduced to a more typical 5 percent with the addition of AWT
facilities in 1981 or by lagoon aging. A program to find
the major cadmium point sources and remove or reduce them
should be implemented as soon as possible. If successful,
the cadmium should be reduced to at least 20 mg/kg. This
would reduce the cadmium to zinc ratio to less than 1 percent.
The quantities of sludge expected for the various effluent
qualities and processes are shown in Table 4-4. We have
used the quantities indicated by Effluent II without bio-
physical sludge processing in preparing the remainder of
this report.
4-8
-------
5.1 BACKGROUND
5.2 DESCRIPTION OF LAGOONS AND DEPOSITS
53 CHEMICAL ANALYSES OF FIELD SAMPLES
5.4 LAGOON EMBANKMENT EVALUATION
5.5 LAGOON ABANDONMENT
5.6 ALTERNATIVE ABANDONMENT PROGRAMS
5.7 RECOMMENDED LAGOON ABANDONMENT
PROGRAM
5.8 SUMMARY
SLUDGE LAGOON STUDY
5
-------
Chapter 5
SLUDGE LAGOON STUDY
5.1 BACKGROUND
The sludge disposal lagoons at the MMSD Nine Springs Sewage
Treatment Works are located just east of the treatment plant
as shown on Figure 5-1. There are two lagoons, one approxi-
mately 45 acres in size, and one approximately 85 acres.
The smaller west lagoon (Lagoon 1) was constructed in about
1942, while the dikes for the larger east lagoon (Lagoon 2)
were installed in 1967.
The dikes were constructed on the westerly edge of an exten-
sive grass-sedge marsh area. The underlying surficial soils
are primarily peat and organic silts. These soils have low
bearing capacity, and consequently the dike sections of
Lagoon 2 have failed twice since their construction. The
two areas of embankment failure are shown on Figure 5-1.
The first failure, along the north dike in April 1970,
resulted in a supernatant spill of approximately 85 million
gallons and a large fish kill. The second failure, along
the south dike in November 1973, was contained with a major
fill hauling effort. A program of maintaining the lagoon
dikes, of pumping lagoon supernatant back to the treatment
plant, and of hauling sludge from the lagoon to farmland has
been initiated by MMSD in an effort to prevent future dike
failures.
As a result of the 1970 dike failure, WDNR required that
MMSD abandon the present method of sludge disposal and take
measures to prevent the recurrence of discharges to the
state waters. This order initiated several studies, most
notably those by Greeley and Hansen Engineers and Roy F.
Weston, Inc., which resulted in the recommendations to
dispose of the sludge on land . To complement the sludge
reuse program, CH2M HILL's study was to include evaluation
of the lagoon problem. As background for this, a lagoon
sampling program was used to provide an assessment of the
environmental impacts of lagoon abandonment alternatives and
of the suitability of the lagoon solids for reuse on land.
Also, the lagoon dikes were investigated to determine their
condition and need for stabilization.
5-1
-------
5.2 DESCRIPTION OF LAGOONS AND DEPOSITS
The lagoon deposits were characterized by sampling and
analysis at 48 locations in the two lagoons. The field
program tasks consisted of (1) determining physical dimen-
sions of each lagoon for sludge deposit quantification, and
(2) collecting samples for physical and chemical charac-
terization of the lagoon deposits and bed material. A
preliminary field study revealed the lagoon bed material to
consist of a peat layer overlying a marl layer.
Field Work Methodologies
A systematic sampling station grid network was established
in each lagoon to provide sufficient areal coverage and
detailed characterization of the two lagoons and their
deposits. Eighteen stations were located in a rectangular
pattern in Lagoon 1, and 30 stations were similarly located
in Lagoon 2. Location of each sampling station is shown on
Figure 5-1.
TYPICAL SLUDGE CORE
5-2
-------
0 300 600
SCALE IN FEET
FIGURE 8-2
REUSE PROGRAM
SITE PLAN
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
S9166.0
-------
Sludge Application Equipment
Truck spreaders should be used as the main method of sludge
application in the first few years because the farmers will
more readily accept them and because they allow the most
flexible operation. Four truck spreaders can handle most of
the first year's peak month sludge application requirement.
One soil injector and one tractor spreader should also be
available in the first year to help meet the peak sludge
handling requirements and to demonstrate the economy of
these sludge application methods. Soil injection should be
used on fields where runoff could be a problem and near
incompatible land use areas such as subdivisions, schools,
parks, etc.
As the sludge use increases in the second and third years,
soil injection and tractor spreader systems should be added
to match the increases. A total of two soil injectors, two
tractor spreaders, and four truck spreaders will be required
for sludge application between the third and tenth years of
the program.
After the lagoons are emptied, the sludge application system
could be reduced to one tractor spreader, one soil injector,
and one truck spreader. The tractor spreader could handle
about half of the acreage by itself. The soil injection
system could handle about one-third of the acreage and would
be used primarily near developments where the sludge reuse
management requires subsoil application of the sludge. The
truck spreader could handle the remainder of the sludge
application requirement.
Sludge Transportation Facilities
Transportation of the sludge to farmland during the first
2 or 3 years will be totally by tank truck. Six tanker
trucks will be required during the peak sludge application
period in the first year. The number of trucks could remain
at six in the second and third years of the reuse program if
several on-farm lagoons are constructed to help level off
the peak period sludge transportation requirement. It is
estimated that by the fifth year of the reuse program, about
20 small on-farm lagoons would be accepted by farmers. A
pipeline should not be installed until a strong market can
be identified in a particular area. By the fifth year of
the reuse program, a large market area should be developed
to make pipeline transport feasible. Several farmers in the
Cottage Grove area have already shown strong interest and
have suggested a distribution site in their area. This area
8-12
-------
would be especially well suited as a central sludge distri-
bution point if a strong market exists because it is some-
what remote from the Nine Springs Treatment Works. With
pipeline transporation, it is assumed that the number of
tanker trucks could be reduced to four.
8.6 REUSE PROGRAM COST
Construction Cost
Reuse Program. The initial construction cost requirements
for the sludge reuse program are presented in Table 8-1.
Additional capital expenditures will be required as the
program grows to install additional facilities such as the
dike across Lagoon 1, on-farm storage lagoons, sludge
transmission pipeline, and additional application equipment.
A year-by-year listing of the anticipated capital costs is
presented in Table B-14. The basis of the cost estimates
are presented in Appendix B.
TABLE 8-1
ESTIMATED INITIAL CONSTRUCTION COST
SLUDGE REUSE PROGRAM
MADISON METROPOLITAN SEWERAGE DISTRICT
ITEM
ESTIMATED*
COST
REUSE PROGRAM
Lagoon Sludge Removal Equipment
Sludge Distribution Equipment
(6 tanker trucks 1 sludge loading dock
2 nurse tanks, 1 slurry pump)
Sludge Application Equipment
(4 truck spreaders, 1 soil injector, 1 tractor spreader!
SUBTOTAL REUSE PROGRAM
UPGRADING AND EXPANSION OF EXISTING
SOLIDS HANDLING SYSTEM
Upgrading
Gravity Thickener Upgrading
Digester Upgrading
Supernatant Pretreatment System
Expansion
Gravitv Thickeners
Flotation Thickeners
Sludge Blenders
Digester and Control Building
Utility Tunnel
SUBTOTAL SOLIDS HANDLING SYSTEM
TOTAL INITIAL CONSTRUCTION COST
Estimated Total Initial Construction Cost
Less Federal Grant |75%l
Less State Grant (5%)
NET COST TO MMSD
S 130,000
457 000
312000
$ 899,000
S 5,000
425,000
2,370,000
110000
650 000
55,000
1,740,000
220,000
S5,575,000
S6 474 000
4 855 000
324 000
S 1 295 000
'Engineering Administration Legal and
Fiscal and Contingencies included
3-13
-------
Upgrading and Expansion of Existing Solids Handling System.
Chapter 4 of the Wastewater Treatment Plan discussed
the need to upgrade the solids handling system of the existing
treatment plant. In Chapters 8 and 9, we discussed the need
to expand the solids handling system to handle the increase
in solids production resulting from various levels of advanced
treatment. Since the solids handling system is an integral
part of the reuse program, we also discussed the desirability
of implementing the upgrading and expansion of the system at
the same time the reuse program is implemented. With this
plan, the sludge handling and disposal problems of the
existing plant can be resolved on a shorter schedule than if
they were implemented separately.
The initial construction cost requirements for the upgrading
and expansion of the system are presented in Table 8-1.
The costs for expansion are based on the assumption that
Effluent II will be required to meet the future discharge
strategy and that a biological nitrification process will be
used to produce an Effluent II. As the load to the treatment
plant increases in later years, additional construction will
be necessary. These costs are summarized in Appendix F of
the Wastewater Treatment Plan.
Program Operation Requirements
Personnel Requirements. Due to the scope of the proposed
reuse program, there will be a need for substantial staff
increases to manage, operate, and monitor the program. One
full-time position will be required to perform the duties
described for the program manager. A full-time position of
clerical help will also be required to support the manager.
The lagoon cleanout program will normally require two men during
the 6-9 months' period of lagoon sludge removal. These two
men should both be trained to operate the dredge. During
some peak sludge reuse periods, two 8-hour shifts may be
required each day. The two experienced dredge operators
could then work the different shifts with the help of a less
experienced man to handle the floating pipeline and guide
cables.
Ten to 14 men will be required for 6-9 months each year to
operate the sludge distribution and land application equip-
ment. The number will depend upon the amount of sludge
reused and the kinds of facilities used each year. There
should be one man for each tanker truck and sludge spreader
truck. The truck loading facilities should be designed so
that the truck drivers can load the trucks and thereby
8-14
-------
eliminate the need of an extra man at the loading facility.
All the sludge application equipment except for the truck
spreader can be operated by the farmer or his hired help.
The District, however, should have up to four men available
to operate any of the sludge application equipment for
farmers who do not supply the labor.
One or two men, depending upon the rate of sludge handling,
will be required to perform miscellaneous chores such as
transporting sludge application equipment to farms, opera-
ting the on-farm lagoon sludge slurry ing pumps, and per-
forming general maintenance of equipment. This will also be
seasonal work lasting 6-9 months a year.
The monitoring program will require one to two people to
collect samples, perform the laboratory analysis, and
assemble and record the data. A detailed breakdown of the
total staff requirements is given on Figure 8-3.
It is apparent from the foregoing that much of the sludge
reuse program staff requirements will be seasonal. The
number will vary from a minimum of three or four full-time
positions (program manager, clerical assistant, and labora-
tory technician[s]) to a possible maximum of about 24 posi-
tions during the peak sludge reuse season (four full-time
positions, four lagoon cleanout equipment operators, six
tanker truck operators, four tractor spreader and soil
injector operators, four truck spreader operators, and two
miscellaneous helpers). Off-season equipment maintenance
and filling on-farm lagoons should be used to keep part of
the seasonal labor force employed year round. The job
descriptions should be carefully written so that off-season
maintenance and related work can be done by part of the
summer sludge handling work force. The District should also
draw on available summer labor whenever possible as many
students would be available for seasonal employment.
A summary of the initial operation and maintenance costs is
presented in Table 8-2. The average cost of labor, $15,300
per year, is based on current union scale with allowances
for inflation and includes a 25-percent allowance for pay-
roll overhead and insurance. The program manager labor cost
is assumed to be about $17,000 per year.
The staff required to operate the expanded solids handling
facilities will also need to be increased. The current
staff assigned to these facilities consists of five men.
After the facilities are completed, it is estimated that the
staff requirements will increase to six men. A summary of
these requirements \s also presented in Table 8-2.
8-15
-------
PROGRAM MANAGEMENT
LAGOON CLEANOUT
SLUDGE DISTRIBUTION
SLUDGE APPLICATION
MONITORING PROGRAM
MISCELLAENOUS
INITIAL"
LAGOONS EMPTY
INITIAL
LAGOONS EMPTY
INITIAL
LAGOONS EMPTY
INITIAL
LAGOONS EMPTY
INITIAL
LAGOONS EMPTY
INITIAL
LAGOONS EMPTY
LEGEND
FULLTIME
Itl SEASONAL
i :.,::"::TJ SEASONAL AND VARIABLE
"INITIAL" REFERS TO FIRST
8-10 YEARS WHEN LAGOON
SLUDGE IS BEING APPLIED TO
LAND
,59166.0
FIGURE 8-3
REUSE PROGRAM
STAFF REQUIREMENTS
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
TABLE 8-2
ESTIMATED INITIAL ANNUAL OPERATION
AND MAINTENANCE COSTS
MADISON METROPOLITAN SEWERAGE DISTRICT
ESTIMATED*
ITEM COST
REUSE PROGRAM
Labor (4 full time, 16 part time) $178.000
Fuel 20 #00
Equipment Maintenance 20,000
Monitoring Program (labor included above) 27,000
SUBTOTAL REUSE PROGRAM $245,000
EXPANDED SOLIDS HANDLING SYSTEM
Labor (6 full timel $115,000
Power 54,000
Chemicals 74,000
Chemical Recovery -55,000
Equipment Maintenance 88,000
Lime Sludge Landfill 25,000
SUBTOTAL SOLIDS HANDLING PROGRAM $301,000
ESTIMATED ANNUAL OPERATION AND $546,000
MAINTENANCE COSTS
"Contingencies included.
Operation and Maintenance Costs. A summary of operation and
maintenance costs for the reuse program and the solids
handling facility is presented in Table 8-2. A detailed
breakdown of operation and maintenance costs for the various
elements of the reuse program and the basis for those costs
are presented in Appendix B of this report. The costs
presented for the solids handling system were developed from
costs presented in Appendix F of the Wastewater Treatment
Plan.
Sludge User Fee
The question of whether or not to charge for the sludge and
the amount of a fee is difficult to answer. If the sludge
is given away, this may imply that the material is bad.
Conversely, too high a charge may discourage use of the
sludge. Based upon the present high interest in the reuse
of sludge shown by the area farmers, we feel that a charge
will be acceptable and recommend that a fee be assessed the
sludge users. The primary objectives of charging a fee are
to control the supply and demand for the sludge and control
the type and location of sludge users. To determine the
charges for sludge users, several criteria must be con-
sidered.
• The cost of sludge must be appreciably less than
the cost of commercial fertilizers to create a
demand for the sludge.
8-17
-------
• Since transport cost is a function of distance,
the cost should be higher for those farther from
the sludge source.
• The cost schedules must be flexible in order to
provide control of sludge supply and demand.
• Special considerations should be available to
farmers who make a commitment to MMSD to accept
sludge for long periods or agree to permanent on-
farm facilities.
To meet all of the above criteria, we recommend that the
following initial sludge user fees be established:
• Assess a one-time flat fee to cover the cost of
the site inspection and recordkeeping.
• Assess a fee for the cost of the annual soil
sampling and analysis.
• Establish a maximum distance from the plant or
distribution center beyond which an extra fee will
be assessed on a ton-mile basis for sludge trans-
portation. No transportation fee would be assessed
to farmers within the maximum distance limit. The
distance can be varied to control sludge supply
and demand.
Special considerations for farmers who make a commitment to
MMSD for sludge reuse could consist of a priority rating for
sludge and application equipment or free delivery in an area
outside of the free delivery radius.
The suggested one-time flat fee for site inspection is $200
for parcels up to 200 acres. Two hundred dollars is the
estimated cost for the initial interview, site inspection,
and opening a set of records. If the parcel is larger than
200 acres, the fee should be increased by $0.25 per acre.
No charge should be made if the site is found to be unsuit-
able for sludge reuse.
The annual cost to the District of soil sampling and analysis
will be about $100 for a 200-acre field. We recommend that
this cost be passed on to the farmer at a fixed rate of
$0.50 per acre each year.
The recommended charge for supplying sludge beyond a speci-
fied free delivery radius from the sludge supply is $1 .50 per
8-18
-------
ton-mile. This rate is approximately equal to the pipeline
transport cost estimate.
Table 8-3 shows the sludge user fees for different circum-
stances. The initial flat fee and soil monitoring cost is
very minor compared to the fertilizer value of the sludge.
The delivery fee will add considerably to the cost of sludge
use, but will still be much less than the value of the
sludge. As with any marketed product, the sludge users
should be told what to expect in return for the fee paid.
In this case, it will be the complete program services of
site inspection, soil testing, product delivery, etc.
TABLE 8-3
EXAMPLE SLUDGE USE FEES
MADISON METROPOLITAN SEWERAGE DISTRICT
SIZE OF LAND PARCEL
FEE
ITEMS
One-time Flat Fee
Annual Sotl Monitoring
WITHIN FREE DELIVERY RADIUS
Total Cost First Year
Cost Each Succeeding Year
5 MILES OUTSIDE OF FREE
DELIVERY RADIUS
Transport Fee'D
Total Cost First Year
Cost Each Succeeding Year
VALUE OF SLUDGE121
40
ACRES
200
20
S 220
$ 20
$ 900
$1,120
$ 920
80
ACRES
$ 200
$ 40
$ 240
$ 40
160
ACRES
$ 200
$ 80
S 280
$ 80
500
ACRES
1.000
ACRES
$ 275 S 400
$ 250 S 500
$ 525 $ 900
S 250 $ 500
$1,800 $3,600 S11,250 $22,500
$2,040 $3,880 $11,775 $23,400
$1,840 $3,680 $11,500 $23,000
$1,800 $3,600 $7,200 $22,500 $45,000
(1) Based upon application rate of 3 tons/acre.
(2) Value of sludge as fertilizer a about $15.00/ton or $45.00/acre.
We recommend that the free delivery radius be set at
12 miles the first year. This will include several large
farmers in the Cottage Grove area who have shown a strong
interest in sludge use at the meetings. The sludge user
fees should be reevaluated every few years to ensure that
the objectives of charging fees are met or to change the
objectives. It should be possible to shorten the free
delivery distance to 10 miles or maybe even 7 miles within a
few years. Reducing the free delivery radius will likely
upset users accustomed to free delivery. Therefore, the
users should be informed from the outset that the distance
may be reduced. Also, a full year advance notice should be
given to affected users. The reuse program costs are based
upon reducing the free delivery distance to 5 miles from the
Nine Springs Works or distribution points by the sixth year
of the reuse program.
8-19
-------
Program Cost Summary
The estimated initial costs for the expanded solids handling
system and sludge reuse program are summarized in Table 8-4.
Also summarized are the cost effects of receiving Federal
grants and the effect of the annual revenue from sludge user
fees.
TABLE 8-4
PROGRAM COST SUMMARY
MADISON METROPOLITAN SEWERAGE DISTRICT
ITEM
TOTAL CONSTRUCTION COST
Annual Debt Service, 7% for 20 years
NET CONSTRUCTION COST, with grants
Annual Debt Service, 7% for 20 years
ANNUAL OPERATION AND MAINTENANCE COST
LESS ANNUAL REVENUE
TOTAL ANNUAL COST, without grants
Cost per Dry Ton Leaving System*
TOTAL ANNUAL COST TO DISTRICT, with grants
Cost per Dry Ton Leaving System*
EXPANDED
SOLIDS
HANDLING
SYSTEM
$5,575,000
526,000
$1,115,000
105,000
$ 301,000
-
$ 827,000
5010
$ 406,000
24.60
REUSE
PROGRAM
$899,000
85,000
$180,000
17,000
$245,000
$5,000
$325,000
1970
$257,000
15 60
TOTAL
SYSTEM
$6,474,000
611,000
$1,295,000
122,000
$ 546,000
$5,000
$1,152,000
69.80
$ 663,000
4020
"16,500 tons solids per year
Based on this summary, the initial annual net cost to the
District for the proposed reuse program is $266,000 per
year. The expansion of the solids handling system will add
another $433,000 per year, bringing the total annual cost of
the entire solids handling and disposal system to $699,000
per year. It has been estimated that the District is cur-
rently spending $272,000 per year for solids handling and
disposal. Of this, about $180,000 per year is spent on the
current sludge reuse program.
Program costs are also often summarized in terms of cost per
dry ton of sludge leaving the treatment plant. This allows
one to compare proposed costs to other projects with a
similar system and also allows comparison with other methods
of solids handling and disposal. The District's program
will initially handle and dispose of all the treatment plant
sludge production and also dispose of accumulated lagoon
sludge. Over the next 8-10 years, it is expected that an
average of 16,500 dry tons of digested sludge will be applied
to farmland each year. Based on this quantity, the estimated
total unit cost for solids handling and disposal will be
$69.80 per dry ton. Of this, about $19.70 per dry ton is
attributable to the reuse program alone. This reuse program
8-20
-------
unit cost is based upon the initial construction and equip-
ment purchase costs and average operation and maintenance
costs during the period of lagoon sludge removal. As shown
in Table B-14, the average cost of sludge reuse through the
year 2000 will be about $31.70 per ton solids. This is
higher due to the several construction and equipment purchase
costs which will occur after the first year of the program.
Also, the quantity of sludge recycled each year will decrease
after the lagoons are emptied.
8-21
-------
9.1 INTRODUCTION
9.2 REVIEW OF SLUDGE DISPOSAL ALTERNATIVES CONSIDERED
9.3 LAND APPLICATION OF SLUDGE STATE OF THE ART
9.4 TREATMENT PLANT SLUDGE CHARACTERIZATION
9.5 SLUDGE LAGOON STUDY
9.6 CONSIDERATIONS FOR AGRICULTURAL REUSE OF SLUDGE
9.7 SLUDGE REUSE PROGRAMS CONSIDERED
9.8 RECOMMENDED SLUDGE REUSE PROGRAM
9.9 RECOMMENDATIONS AND IMPLEMENTATION SCHEDULE
SUMMARY, CONCLUSIONS,
AND RECOMMENDATIONS
-------
Chapter 9
SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
A summary of the findings and conclusions of this report on
sludge reuse is presented here, chapter by chapter.
9.1 INTRODUCTION
The Madison Metropolitan Sewerage District (MMSD), in compli-
ance with Wisconsin Pollutant Discharge Elimination System
Permit No. WI-0024597, must prepare a facilities plan for
advanced waste treatment, sludge disposal, and effluent
disposal. This report is an investigation of sludge
disposal. The objective is to develop a plan for abandoning
sludge disposal in the existing lagoons and implementing
agricultural reuse of sludge produced in the future. MMSD
has been disposing of sludge by discharge to lagoons in the
Nine Springs Marsh during the past 33 years. In 1970 a
lagoon dike failure prompted the District to seek a more
reliable sludge disposal method.
9.2 REVIEW OF SLUDGE DISPOSAL ALTERNATIVES CONSIDERED
Major studies of sludge disposal were performed for MMSD by
Creeley and Hansen Engineers and by Roy F. Weston, Inc.,
Environmental Scientists and Engineers. Alternatives inves-
tigated by Creeley and Hansen Engineers included the fol-
lowing: A. Spread dried digested sludge on land, B. Incin-
erate digested sludge, C. Incinerate raw sludge, D. Heat
treat and landfill digested sludge, and E. Apply liquid
digested sludge to land. They determined that Alternative E
would be the most cost effective.
The 1974 Weston study investigated several methods of sludge
treatment and disposal. Their evaluations and testing
indicated that dewatering the sludge for incineration would
be costly to accomplish. Sanitary landfill, land appli-
cation of liquid sludge, and land application of compost
were found to be suitable methods and were analyzed on the
basis of costs. Of these, a system for land application of
liquid sludge was determined to be most cost effective.
The MMSD staff prepared an addendum to the Weston report
which included additional sludge disposal alternatives. Of
9-1
-------
seven alternatives investigated, anaerobic digestion of
thickened raw sludge followed by pipeline transportation to
a lagoon and land irrigation was found to be most economical.
In June 1974, based upon the aforementioned studies, the
MMSD Commission resolved that liquid digested sludge from
the Nine Springs Treatment Works would be handled through
the process of application on land.
9.3 LAND APPLICATION OF SLUDGE STATE OF THE ART
In reviewing various sludge reuse projects in this country
and in Great Britain, several basic practices were deter-
mined. Sludge has been applied at what can be described as
fertilization, high-rate fertilization, and disposal rates.
The fertilization application rate allows the most beneficial
use of sludge nutrients. It is also evident that the coopera-
tion of the local farming community is essential for a
successful sludge recycle system. Experience of the Herts
Authority in Great Britain emphasizes the importance of a
well-managed distribution operation and a strong marketing
program.
9.4 TREATMENT PLANT SLUDGE CHARACTERIZATION
The quality and quantity of sludge produced at the Nine
Springs Works were determined as a basis of the facilities
planning study. The sludge presently produced in the diges-
ters was analyzed to characterize its condition. Estimates
of the future sludge quality and quantity were also made
based upon the sludge handling methods being investigated in
the Advanced Waste Treatment (AWT) facilities plan study.
The quantity of sludge expected from the treatment plant is
as follows: The sludge production in 1976 will be approxi-
mately 5,800 dry tons. In 1977 when the Fifth Addition to
the treatment plant goes on line, the sludge production is
expected to increase to about 6,000 dry tons per year. The
sludge quantity is then expected to increase in proportion
to the influent flow volume until 1981 when the AWT facil-
ities are expected to go on line. With the addition of AWT,
the sludge quantity will again increase to about 6,700 dry
tons and will continue to increase gradually to about
8,500 tons dry per year in 2000. Level II treatment, an
effluent with 10 mg/l of biochemical oxygen demand and
10 mg/l suspended solids, was used as the basis of this
planning study. The character and quantity of sludge pro-
duced in other levels of treatment were discussed in
Section 4.2.
9-2
-------
The sludge quality is summarized in Table 4-3. The solids
content, which is now 2.3 percent, is expected to be increased
to about 5 percent; and the nitrogen content, now 10.5 per-
cent, is expected to be reduced to about 5 percent with the
addition of AWT facilities or by lagoon aging. The cadmium
content of the treatment plant sludge is currently high
compared to the zinc content. A program to find and reduce
the major cadmium point sources has been started and should
be continued.
9.5 SLUDGE LAGOON STUDY
The quantity and quality of the sludge in the Nine Springs
Lagoons were determined by extensive field sampling and
laboratory analyses. The depth of sludge in the 135 acres
of lagoons varies from 2 feet to 7.1 feet in Lagoon 1 and
3.9 feet to 6.2 feet in Lagoon 2. The percent dry solids
content averages 12.9 and 8.2 in Lagoons 1 and 2, respec-
tively. The total sludge quantity in the lagoons is approxi-
mately 89,700 dry tons.
The quality of the lagoon sludge, as shown in Table 5-1,
indicates its suitability for agricultural reuse. The
sludge sampling investigation included gathering samples of
the underlying peat and marl to determine leaching of sludge
constitutents and indicated that there is little or no
leaching past the first foot of the peat-soil layer. A
hydrogeologic investigation of the lagoon area and monitoring
of water quality in Nine Springs Creek indicate only minor
leaching occurs through the dikes.
The condition of the lagoon embankments was studied in
detail, and a special report was presented to MMSD which
concluded that failures and possible sludge spills are
imminent and recommended that certain portions of the dikes
be stabilized. The District has proceeded with the recommended
dike stabilization program.
A program for abandonment of the present method of sludge
disposal in the Nine Springs Lagoons was prepared as required
by the Wisconsin Department of Natural Resources. The
recommended program consists of removing all sludge from
Lagoon 2 and from approximately the east half of Lagoon 1.
The west half of Lagoon 1 will continue to be used for
seasonal storage of the treatment plant sludge.
9-3
-------
9.6 CONSIDERATIONS FOR AGRICULTURAL REUSE OF SLUDGE
A study area consisting of the land within a 10-mile radius
of the Nine Springs Sewage Treatment Works was delineated as
a basis for discussion of agricultural reuse of sludge. The
study area contains about 91,000 acres of very productive
farmland. Its soils, land use, and ground-water conditions
were investigated for their suitability for sludge reuse.
Based upon the site investigations, it was determined that
about 40,000 acres is suitable for sludge application.
Farmers representing more than 5,000 acres of farmland have
already shown a strong interest in having sludge applied to
their land. The amount of farmland available for sludge
reuse is expected to increase rapidly after the reuse program
is started.
The amount of land required for reuse of all the Nine Springs
Sewage Treatment Works sludge will be between 5,200 and
5,700 acres until the lagoons are emptied. Thereafter,
about 2,400 to 3,000 acres will be needed each year. The
land area required is based upon recommended annual and
total sludge application rates which are shown in
Tables 6-5 and 6-6. The sludge application rates were
established to prevent potentially harmful overapplication
of crop nutrients and heavy metals.
Chapter 6 also included criteria for determining the suit-
ability of particular sites for sludge application and the
site management necessary to protect the surrounding environ-
ment.
9.7 SLUDGE REUSE PROGRAMS CONSIDERED
Several alternatives were developed and then compared to
select a cost-effective, reliable, and farm-community-
supported sludge reuse program. The programs eliminated
from detailed consideration included the following:
• MMSD ownership and operation of a site for recycle
of all the treatment plant and lagoon sludge.
• High-rate fertilizer and disposal methods of
sludge application to the land.
District ownership and operation of a site for recycle of
all the treatment plant and lagoon sludge was eliminated
because it was concluded, based on previous experience with
the approach, that it would not be acceptable to the farm
community. This program would require the purchase of
9-4
-------
several thousand acres of Dane County farmland and reloca-
tion of many farming and rural families, which would be very
expensive and politically difficult, if not impossible to
implement. The high-rate fertilization and disposal applica-
tion rates were eliminated from consideration because they
would result in environmental degradation and wasting of
valuable nutrients.
Three alternative reuse programs were selected for further
study. They are:
• Program 1—Market all sludge to farmers.
• Program 2—Lease land for short periods for sludge
application.
• Program 3—Combination of marketing and land
leasing.
In Reuse Program 1, the District would make sludge available
to area farmers as they request it for fertilizer rate
application to their farmland. A public relations program
would be developed to aid in marketing the sludge. The
farmer would have complete control over his land. He would
contact MMSD when he wanted sludge, then he and a District
representative would determine the suitable time, location,
and application rates for sludge application. MMSD would be
responsible for monitoring and managing the program.
In Reuse Program 2, the District would lease or rent land
from farmers for sludge application. Since sludge would be
applied during the growing season, no crops would be grown
that year. The lease cost, therefore, would have to offset
the net returns the farmer would have otherwise received
from a crop plus the fixed costs of equipment and land
ownership. Two purposes for obtaining leases for the land
are: (1) assuring the District of land for sludge appli-
cation for some period in advance, and (2) scheduling of
sludge application evenly throughout the summer, thereby
reducing peak handling requirements. The farmer would
benefit from knowing he would not be hurt by crop failure,
fertilizer would be applied onto his land, and he would not
need to farm the land for one season.
Sludge Reuse Program 3 would be set up to market sludge to
farmers for use on their land as in Reuse Program 1, plus it
would include provisions for MMSD leasing land as in Pro-
gram 2. MMSD-leased land would be used to apply sludge
during the low-use months of July and August. This would
9-5
-------
spread the application period out more evenly over the year
and thus reduce peak sludge handling requirements.
Sludge Reuse Program 1, market all sludge to farmers, was
determined to be the best apparent program based upon farmer
acceptance, reliability, and costs. Program 2, leasing land
for sludge application, is not suitable because it would not
be acceptable to enough farmers. Reuse Program 3, a combina-
tion of Programs 1 and 2, is not cost effective when compared
to Program 1 but could be employed in some special cases.
In the event the sludge reuse market is lost, a contingency
plan must be available for sludge handling. Alternative
plans considered included:
• Acquisition of several thousand acres of District-
owned or option-to-control land available for
sludge application.
• Have facilities for incineration or dewatering and
landfill available for sludge disposal.
• Retain capacity to store sludge until a permanent
solution can be found.
The first and second alternatives are not feasible because
of the high cost and impracticability. The third alternative
is recommended: store the sludge until a permanent solution
can be found. The west half of the Lagoon 1 storage area
will have capacity to store 75 percent of 1 year's sludge
production at 2.3 percent solids. With concentration to
10 percent solids, as is currently achieved after a freeze-
thaw cycle, this storage area could hold 3 years' treatment
plant sludge production. Also, the dikes surrounding the
east half of Lagoon 1 should be left intact, except as
required to allow drainage, after the sludge is removed.
This area would then, with minor rehabilitation, be suitable
for storage of an additional 3 years' sludge production in
an emergency.
If loss of a sludge reuse market is to occur, it will most
likely happen in the first years of the program before
sludge reuse becomes a common, well-accepted practice.
After many years of sludge reuse, the chance of losing the
sludge market would be very remote. Sludge marketing is a
vital element of the sludge reuse program and all should be
done, especially by way of public education, to assure the
program's success.
9-6
-------
Sludge distribution and application methods were also inves-
tigated . Tanker truck and pipeline were determined to be
the most feasible transportation methods. A pipeline would
be constructed after a market for sludge develops in an area
large enough to make the investment in a pipeline cost
effective compared to truck transportation. Other facilities
which would be included in the distribution system would be
small on-farm storage lagoons and nurse tanks.
Methods considered for sludge application included sprinkler
application, soil injection, truck spreading, and tractor
spreading. The big gun sprinkler system is least suitable
because of its adverse environmental impact caused by visi-
bility and odor potential. The remaining methods are all
acceptable, but each have their own major advantage. Subsoil
injection's advantage is that it places the sludge out of
sight of the public. Truck spreading is most mobile and
flexible. Tractor spreading is the quickest and most econom-
ical method.
9.8 RECOMMENDED SLUDGE REUSE PROGRAM
The major components of the recommended sludge reuse program
are program mangement, monitoring, marketing, and sludge
handling. The reuse program operation and methods of reuse
must be managed by MMSD to ensure orderly, efficient opera-
tion and environmentally acceptable land application. The
major components of program management are a program manager,
initial interview with the farmer and site screening, rate
determination, sludge application, and recordkeeping. The
District must appoint a person to manage the sludge reuse
program.
The sludge reuse program must be monitored to protect the
environment and to provide farmer confidence in the program.
The program includes monitoring of the sludge, soils,
crops, and ground water. The monitoring program is explained
in detail in Appendix E.
The District must work to develop a large reliable market of
farmers who want sludge applied to their land. Tools which
have been used successfully to market sludge are an informa-
tional brochure, meetings with farmers, demonstration plots,
and the designation of a trade name.
In addition, it is necessary to upgrade the solids handling
system of the existing treatment plant. In Chapters 8 and 9
of the Wastewater Treatment Plant report, we discussed the
need to expand the solids handling system to handle the
9-7
-------
increase in solids production resulting from various levels
of advanced treatment. Since the solids handling system is
an integral part of the reuse program, we also discussed the
desirability of implementing the upgrading and expansion of
the system at the same time the reuse program is implemented.
With this plan, the sludge handling and disposal problems of
the existing plant can be resolved on a shorter schedule
than if they were implemented separately.
It is expected that the District can obtain regulatory
agency acceptance and begin the recommended sludge reuse
program in early 1977. As soon as the program is accepted,
the District should begin to set up the required facilities.
For the first year, 1978, four truck spreaders, one soil
injection system, one tractor spreader system, six tanker
trucks, one loading dock, and two nurse tanks are recommended,
It is estimated that about five on-farm lagoons can be
arranged and built each year during the second through fifth
years of the program. Another set of soil injector and
tractor spreader systems will probably be required in about
the third year of the program. After the existing lagoons
are emptied, in about 1987, the District will probably need
only one truck spreader, one soil injector, and one tractor
spreader. These items will probably need to be replaced in
1987 and 1997. We estimate that it will be feasible to
build a pipeline and remote loading dock in about 1982.
Also, the existing lagoons should be emptied enough by about
1984 to allow construction of a dike across Lagoon 1 for the
seasonal storage lagoon.
We recommend that sludge users be assessed a fee to provide
control of the supply and demand of the sludge. The fee
structure should include a one-time flat fee to cover the
cost of the site inspection and record keep ing, a fee for the
cost of the annual soil sampling and analysis, and a trans-
portation fee based on haul distance from a distribution
center. Also, the fee should be considerably less than the
cost of commercial fertilizer to encourage the use of sludge.
The total average annual costs for the lagoon abandonment
and sludge reuse program is estimated to be $350,000 per
year for the next 20 years. It is expected that the District
will receive up to 75 percent Federal grants to assist in
the construction of the required facilities. If this occurs,
the total average annual cost will drop to an estimated
$212,000 per year. For the average residential customer,
this will amount to an annual charge of about $1.85 per year
or about 15 cents per month. This, of course, is the cost
of only the sludge reuse program. This does not
9-8
-------
include the cost of sludge handling prior to digestion,
sludge digestion, and the treatment of wastewater itself.
In 1975 the District spent a total of $172,000 for sludge
application to farmland. For the average residential cus-
tomer, this amounted to about $1.15 per year, or about
10 cents per month of their current bill for sewer service.
The proposed program will, therefore, require an increase of
about $0.70 per year or 6 cents per month. Based on this
minimal increase, we believe the proposed project is feasible
and well within the financial capabilities of the community.
9.9 RECOMMENDATIONS AND IMPLEMENTATION SCHEDULE
Based upon the findings and conclusions of this report, we
recommend that the Commissioners of the Madison Metropolitan
Sewerage District:
• Adopt the findings of this report.
• Submit the report to the appropriate agencies as
part of the Facility Plan for the Madison Metro-
politan Sewerage District.
• Proceed with the existing sludge disposal program
until final acceptance of the proposed program.
• Authorize appropriate engineering to assist the
District in proceeding with selected elements of
the proposed sludge reuse program prior to final
regulatory agency acceptance of this report. The
elements selected will serve to upgrade the existing
program without any significant capital investment.
The elements include:
1. Appointment of a full-time sludge reuse
manager.
2. Implementation of the program management
tools outlined in Appendix D as present
equipment will allow.
3. Implementation of a sludge, soil, ground-
water, and crop monitoring program, as out-
lined in Appendix E.
4. Development of appropriate marketing tools
necessary to launch a strong marketing program.
9-9
-------
5. Implementation of an industrial waste survey
to locate sources of heavy metals, partic-
ularly cadmium.
6. Revision of the sewer service ordinance to
require users to pretreat their wastes for
the removal of heavy metals.
Separate the construction of the proposed new
solids handling facilities from the proposed
advanced waste treatment addition and combine them
with the implementation of the sludge reuse pro-
gram.
Adopt the implementation schedule shown on
Figure 9-1. A condensation of the required action
items is as follows:
1. Adopt and submit plan and EAS
to WDNR and DCRPC June 1976
2. Authorize appropriate engineer-
ing to assist District in imple-
menting selected elements of
sludge reuse program June 1976
3. Authorize final design engineer-
ing of program facilities subject
to DNR and EPA approval March 1977
4. Advertise for Bids November 1977
5. Award Contracts January 1978
6. Start up Sludge Reuse
Program August 1978
7. Start up New Solids Handling
Program November 1979
9-10
-------
REGULATORY AGENCY REVIEW
• ADOPT AND SUBMIT PLAN AND EAS
TO WDNR AND DCRPC
• AUTHORIZE ENGINEERING TO ASSIST
DISTRICT IN IMPLEMENTING SELECTED.
ELEMENTS OF PROGRAM
WDNR CERTIFIES PLAN TO EPA.
<*"
• EPA COMPLETES IMPACT STATEMENT e
V*
• STEP 2 GRANT (DESIGN) APPLICATION
• DCRPC COMPLETES A 95 REVIEW s
• STEP 1 GRANT (STUDY) PAYMENT /
• STEP 2 GRANT AWARD
IMPLEMENTATION OF REUSE PROGRAM •
• AUTHORIZE DESIGN ENGINEERING i"
H
• PREPARATION OF PLANS AND SPECIFICATI*i
'4
• WDNR REVIEW OF PLANS AND SPECIFICA1 *
• STEP 2 GRANT PAYMENT ^
A
• STEP 3 GRANT (CONSTRUCTION) APPLICAT4
*
• STEP 3 GRANT AWARD ^
• ADVERTISE FOR BIDS *
"H.
• RECEIVE BIDS ?
• AWARD CONTRACTS .
• CONSTRUCTION AND STEP 3 GRANT PAYIV'
• STARTUP SLUDGE REUSE PROGRAM _,
IMPLEMENTATION OF NEW SOLIDS HAN?
• AUTHORIZE DESIGN ENGINEERING
• PREPARATION OF PLANS AND SPECIFICAT
• WDNR REVIEW OF PLANS AND SPECS
• STEP 2 GRANT PAYMENT
• STEP 3 GRANT APPLICATION
• STEP 3 GRANT AWARD
• ADVERTISE FOR BIDS
• RECEIVE BIDS
• AWARD CONTRACTS.
• CONSTRUCTION AND STEP 3 GRANT PAYIV f
*
• STARTUP NEW SOLIDS HANDLING FACILIT*
FIGURE 9-1
SLUDGE REUSE PROGRAM
IMPLEMENTATION SCHEDULE
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
S9166.0
-------
REFERENCES
American Public Health Association, American Water Works
Association, and Water Pollution Control Federation.
1971. Standard Methods for the Examination of Water
and Wastewater. 13th Edition, New York: American
Public Health Association, Inc.
American Society of Agricultural Engineers. 1975. Agricul-
tural Machinery Management Data. ASAE D230.2.
Ayers, Roberts., and Roy L. Branson. 1975. Guidelines for
Interpretation of Water Quality for Agricuture.
University of California Cooperative Extension.
Black, C. A., Ed. 1965. Methods of Soil Analysis, Number 9
in the series Agronomy, two parts. Madison, Wis-
consin: American Society of Agronomy, Inc.
Bouchard, Aristide. 1973. Determination of Mercury After
Room Temperature Digestion by Flameless Atomic
Absorption. Atomic Absorption Newsletter,
12, 5.
Bower, C. A. and L. V. Wilcox. 1965. Soluble Salts. In
Methods of Soil Analysis, Part 2, Chemical and
Microbiological Properties. Editor-in-Chief,
C. A. Black. No. 9 in the series Agronomy.
Burd, R. S. 1968. A Study of Sludge Handling and Disposal.
Water Pollution Control Research Series Publication
No. WP-20-4. Federal Water Pollution Control
Administration, U.S. Department of Interior.
Burge, W. D. 1974. Pathogen Considerations. In Factors
Involved in Land Application of Agricultural and
Municipal Wastes. ARS, USDA.
Caldwell, James S.; Raymond J. Lishka; and Earl F. McFarrenn.
November 1973. Evaluation of a Low-Cost Arsenic
and Selenium Determination at Microgram-per-Liter
Levels. Water Technology Quality.
R-1
-------
Chapman, H. D. 1965. Cation-Exchange Capacity. In
Methods of Soil Analysis, Part 2, Chemical and
Microbiological Properties. Editor-in-Chief,
C. A. Black. No. 9 in the series Agronomy.
Chapman, Homer D., and Parker F. Pratt. August 1961.
Methods of Analysis for Soils, Plants, and Waters.
University of California, Division of Agricultural
Sciences.
Chapman, Homer D., Ed. 1966. Diagnostic Criteria for
Plants and Soils. Riverside: University of
California, Division of Agricultural Sciences.
Chemical Week. 13 August 1975. Fertilizer Shipments
Decline.
CH2M HILL. 1975. Geotechnical Evaluation of Sludge Lagoon
Embankments. Special report for MMSD.
Cline, Denzel R. 1965. Geology and Ground-Water Resources
of Dane County, Wisconsin. Water Supply Paper 1779-U.
USCS and University of Wisconsin Geological and
Natural History Survey.
Cliver, D. 0. Virus Association With Wastewater Sludges. To
be published in the November 1975 issue of Environ-
mental Letters.
Crop Reporting Board, US DA. 1973. Commercial Fertilizers,
Consumption in the United States Year Ended June 30,
1972.
Cunningham, J. D. 1974. The Phytotoxic Effects of Heavy Metals
in Sewage Sludge. Masters Thesis, University of
Wisconsin.
Dean, R. B.,andJ. E. Smith, Jr. 1973. The Properties of
Sludges. In Proceedings of the Joint Conference
on Recycling Municipal Sludges and Effluents on
Land. Champaign, Illinois.
Ellis, B. C. 1973. The Soil as a Chemical Filter. In
Recycling Treated Municipal Waste Water and Sludge
Through Forest and Cropland. Sopper, W. E. and
L. T. Kardos editors. Penn. State Press.
R-2
-------
Ellis, RoscoeJr.; John J. Hamway; George Holmgren; Dennis R.
Keeney; and O. W. Bidwell. 1975. Sampling and
Analysis of Soils, Plants, Wastewaters, and Sludge.
North Central Regional Publication 230.
EPA Great Lakes Region Committee on Analytical Methods.
1969. Chemistry Laboratory Manual—Bottom Sediments.
EPA National Environmental Research Center. 1974.
of Chemical Analysis of Water and Wastes.
Methods
Epstein, Rains, and Menis. 1975.
Spectroscopy, 20, 1.
Canadian Journal of
Ewing, B. B., and R. I. Dick. 1970. Disposal of Sludge on
Land. In Water Quality Improvement by Physical
and Chemical Processes. University of Texas
Press, Austin, Texas.
Greeley and Hanson, Engineers. 1971. Report on Sewage Treat-
ment Additions to the Nine Springs Sewage Treatment
Works for MMSD.
Holt, C. L. R., Jr., and E. L. Skinner. 1973. Ground Water
Quality in Wisconsin Through 1972. University of
Wisconsin Extension, Information Circular Number 22.
Issac, R. A., and J. D. Kerber. 1971. Instrumental Methods
for Analysis of Soils and Plant Tissue, pp 17-37.
Edited by L. M. Walsh. Soil Science Society of
America, Inc., Madison, Wisconsin.
Keeney, Dennis R.; Kwang W. Lee; and LeoM. Walsh. 1975.
Guidelines for the Application ofWastewater
Sludge to Agricultural Land in Wisconsin. Wisconsin
Department of Natural Resources Technical Bulletin
No. 88.
Kelling, K. A.; A. E. Peterson; J. A. Ryan; L. M. Walsh; and
D. R. Keeney. 1974. Crop Response to Liquid
Digested Sewage Sludge. In Proceedings of the
International Conference on Land for Waste Manage-
ment, Ottawa, Canada.
Konrad, J. G., and S. J. Kleinert. 1974. Surveys of Toxic
Metals in Wisconsin: Removal of Metals From Waste
Waters by Municipal Sewage Treatment Plants.
Technical Bulletin No. 74, Wisconsin Department of
Natural Resources.
R-3
-------
Madison Metropolitan Sewerage District Staff. 1974. Addendum
to Nine Springs Sewage Treatment Works Sludge
Disposal Study for Madison Metropolitan Sewerage
District.
. 1975. Chronological Report on Nine Springs Sewage
Treatment Plant Sludge Disposal.
Malina, J. F., Jr.; K. R. Ranganathon; B. E. D. Moore; and
B. P. Sagik. 1974. Poliovirus Inactivation by
Activated Sludge. In Virus Survival in Water and
Wastewater Systems. Center for Res. in Water
Resources, University of Texas.
Melsted, S. W. 1973. Soil-Plant Relationship, Some Practical
Considerations in Waste Management. Proceedings
of the Joint Conference on Recycling Municipal
Sludges and Effluents on Land. Champaign,
Illinois, pp 121-128.
Metropolitan Sanitary District of Greater Chicago. 1974.
U.S. EPA notice of intent to issue a policy state-
ment of acceptable methods for the utilization or
disposal of sludge from publicly owned wastewater
treatment plants.
Nebiker, John H. 1967. Drying of Wastewater Sludge in the
Open Air. Journal Water Pollution Control Federa-
tion. 39(4): 608-626.
Page, A. L. 1974. Fate and Effects of Trace Elements in
Sewage Sludge When Applied to Agricultural Lands,
A Literature Review Study. For Office of Research
and Development, U.S. EPA.
Page, A. L., and F. T. Bingham. 1973. Cadmium Residues in
The Environment. Residues Rev. 48:1-44.
Pratt, P. F. 1965. Sodium. In Methods of Soil Analysis,
Part 2, Chemical and Microbiological Properties.
Editor-in-Chief, C. A. Black. No. 9 in the series
Agronomy.
Roberts, S.; R. V. Vodraska; M. D. Kauffman; and E. H.
Gardner. 1971. Methods of Soil Analysis Used in
the Soil Testing Laboratory at Oregon State Uni-
versity Special Report No. 321. Agricultural
Experiment Station, Oregon State University,
Corvallis.
R-4
-------
Roy F. Weston, Inc. Environmental Scientists and Engineers.
1974. Nine Springs Sewage Treatment Works Sludge
Disposal Study for MMSD.
Ryan, J. A., and D. R. Keeney. 1975. Ammonia Volatilization
from Surface-Applied Wastewater Sludge. In
Journal WPCF. 47(2): 386-393.
Ryan, J. A.; D. R. Keeney; and L. M. Walsh. 1973. Nitrogen
Transformations and Availability of an Anaerobically
Digested Sewage Sludge in Soil. In J. Environ.
Quality. 2(4): 489-492.
Schneider, I. F., and A. E. Erickson. 1972. Soil Limitations
for Disposal of Municipal Waste Waters. Research
Report 195, Michigan State University, Agricultural
Experiment Station.
Schulte, E. E.; C. C. Olsen; and J. J. Censen. Revised 1975.
Wisconsin Soil Testing and Plant Analysis Pro-
cedures. Soils Department, University of Wis-
consin, Madison.
Schulte, E. E.; L. M. Walsh; and H. B. Pionke. 1968.
Sampling Soils for Testing. Circular 664. Univer-
sity Extension, University of Wisconsin, Madison.
Soil Conservation Service. 1967. Soil Survey Laboratory Data
and Descriptions for Some Soils of Wisconsin.
Soil Survey Investigations Report No. 17.
. Soil Survey Laboratory Data and Descriptions for
Some Soils of Indiana. Soil Survey Investigations
Report No. 18.
. Soil Survey Laboratory Data and Descriptions for Some
Soils of Illinois. Soil Survey Investigations
Report No. 19.
. 1970. Soil Interpretations, A Guide to Land Use and
Conservation Planning. (Interim Dane County Soil
Survey.)
U.S. Department of Commerce, National Oceanic and Atmospheric
Administration. 1972. Meteorological Data For
the Current Year at Truax Field, Madison, Wisconsin.
U.S. Environmental Protection Agency. 1974. Methods for
Chemical Analysis of Water and Wastes.
R-5
-------
. 1975. Municipal Sludge Management: Environmental
Factors supplement to the Federal Guidelines:
Design, Operation, and Maintenance of Waste-water
Treatment Facilities. In process of completion.
. Great Lakes Region Committee on Analytical Methods.
1969. Chemistry Laboratory Manual—Bottom Sedi-
ments .
. Office of Research and Development. August 1975.
Proceedings Second National Conference on Municipal
Sludge Management and Disposal.
. Technology Transfer. 1974. Process Design Manual
for Sludge Treatment and Disposal.
U.S. Public Health Service. 1962. Drinking Water Standards.
Publication 956.
University of California, Division of Agricultural Sciences.
December 1973. Advances and Innovations in Pro-
cedures for Soil, Plant, and Water Analysis.
Statewide Conference.
Ure, A. M., and C. A. Shand. 1974. The Determination of
Mercury in Soils and Related Materials by Cold-
Vapour Atomic Absorption Spectrometry. Analytica
ChimicaActa, 72.
Walsh, L. M. 1975. Mineralization of Organic Nitrogen in
Digested Sludge When Applied to Soils. Unpublished
report.
Walsh, Leo, and James Beatin, Eds. 1974. Soil Testing and
Plant Analysis. Soil Science Society of America,
Madison, Wisconsin.
Walters, H. M., Agricultural Statistician in Charge, Wisconsin
Statistical Reporting Service, 1974 Wisconsin
Agricultural Statistics.
Warzyn Engineering and Service Company, Inc. 1970. Sludge
Dike Investigation, Nine Springs Plant, Madison,
Wisconsin.
Water Resources Task Group. 1971. Planning For Dane County
Water Resources Development and Management. For
Dane County Regional Planning Commission.
R-6
-------
Wischmeier, Walter H. 1965. Predicting Rainfall-Erosion
Losses from Cropland East of the Rocky Mountains.
Agriculture Handbook No. 282. USDA, SCS.
Wisconsin Department of Natural Resources Division of Environ-
mental Standards. 1975. Wisconsin Well Construc-
tion and Pump Installation Standards and Related
Information. In Wisconsin Administrative Code.
4th Edition.
Wisconsin Statistical Reporting Service. 1967. Wisconsin
Weather Causes, Variations and Effects.
. 1970. Snow and Frost in Wisconsin.
. 1974 Wisconsin Assessor Farm Statistics for Dane
County, Wisconsin.
R-7
-------
0 300 600
SCALE IN FEET
FIGURE 5-1
SLUDGE LAGOON
FAILURE ZONES AND
SAMPLING STATIONS
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
S9166.0
-------
The field sampling was performed in March 1975 while the
lagoons were frozen. Sampling consisted of boring through
the ice with an ice auger and measuring the ice thickness.
Ice samples were collected at selected stations and placed
in plastic containers. Sludge samples were then obtained by
coring with clear plastic pipes fitted with an adjustable
rubber stopper attached to a nylon cord as shown on
Figure 5-2. With the stopper end of the pipe touching the
sludge surface, the pipe was slowly pushed into the sludge
until a solid bottom was felt. The stopper was kept at the
surface of the lagoon by the taut line as the pipe was
pushed down. This created a vacuum for recovering the
liquid sludge in the pipe. When the more resistant lagoon
bottom was reached, a measurement of the empty portion of
pipe was made and subtracted from its length (8 feet) to
yield the depth of the sludge layer. The pipe was then
pushed into the bottom to obtain a peat bottom plug, and the
additional length of pipe pushed into the peat was measured
and recorded. The core was then retrieved, capped, and
numbered. With the core in an upright position, measurement
and identification of the layered masses (peat, sludge,
marl) were then made.
At stations where a peat plug could not be obtained due to
the solidness of the sludge, the location of the peat mass
was determined with a commercial peat sampler.
COLLECTING SAMPLE FROM PEAT SAMPLER
At selected stations, peat and marl samples were taken with
the peat sampler. Peat samples were taken at 3-foot inter-
vals until the marl layer was reached. Samples were placed
5-4
-------
2" O.D. PIPE
EYEBOLT
NUT
ADJUSTING NUT
-NYLON CORD
WASHER
RUBBER STOPPER
FOR SUCTION
WASHER
S9166.0
FIGURE 5-2
CORING APPARATUS
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
in plastic containers as shown in photo. Background samples
were taken from the nearby swamp by shovelling with the ice
auger and with the peat sampler.
All sludge cores were frozen in the upright position and
packed in insulated crates with dry ice for air freight
delivery to the laboratory. Ice, peat, and marl samples
were frozen and shipped with the sludge cores for analysis.
Results of Field Work
Depth of Sludge. The sludge depths in Lagoon 1 decreased
from west to east and ranged from 2-7.1 feet as shown on
Figure 5-3. This may be attributed to the contour and slope
of the bed and the settling of solids near the sludge
discharge pipe on the west dike wall. Cores taken from
Stations 1 through 4 had the consistency of a dry paste as
opposed to sludge cores of lesser viscosity taken progres-
sively eastward. In general, the vertical profile of the
lagoon consisted of an ice-soil mass mixed with shallow
rooted vegetation approximately 1 foot thick, the sludge
layer, 2-7 feet thick, and a peat bed at least 5 feet thick
overlying a marl layer. Peat and soil layers were entrapped
between the sludge layer at Stations 2 and 10.
The sludge depths in Lagoon 2 ranged from 3.9 feet to
17.2 feet, as shown on Figure 5-3. However, the 17-foot
depth occurred only at Station 48 and was the result of
dredging the peat bed for dike reinforcement at the south-
east corner several years ago. The sludge samples from
Lagoon 2 were less viscous than those taken from Lagoon 1.
A 1- to 4-foot-thick layer of peat mixed with sludge overlays
the peat bed at Stations 32, 36, 39, and 42. The vertical
profile was similar to that of Lagoon 1, and layers of a
peat-sludge mixture were entrapped within the sludge at
Stations 32, 36, 39, 42, and 44.
Volume of Lagoon Deposits. The lagoon volumes were calcu-
lated with the aid of a computer using the sludge depth data
and the aerial photographs for dimensions and by making
assumptions of the sludge depths along the dike walls. The
results indicate Lagoon 1 has a sludge volume of over
449,000 cubic yards (90,700,000 gallons) and Lagoon 2 over
594,000 cubic yards (120 million gallons).
The average percent dry solids analyses were 12.9 and 8.2
for Lagoons 1 and 2, respectively. This is calculated to
48,700 dry tons of sludge in Lagoon 1 and 41,000 dry tons of
sludge in Lagoon 2, for a combined total of 89,700 dry tons
of sludge material.
5-6
-------
5.3 CHEMICAL ANALYSES OF FIELD SAMPLES
In addition to physically describing the lagoon contents,
several chemical analyses were performed to characterize the
quality of the lagoon contents and to determine if any of
the constituents of the lagoon sludge were leaching from the
lagoon and entering the ground water.
Fourteen lagoon sludge samples were evenly divided and
analyzed in two different CH2M HILL laboratories for mercury,
copper, and zinc. The analytical results were cross-checked
as part of a quality assurance program. There was close
agreement between the laboratories' results.
Characterization of Lagoon Sludge
To characterize the sludge in each lagoon, several selected
cores were composited and analyzed for zinc, copper, cadmium,
nickel, mercury, potassium, total phosphate phosphorus,
total Kjeldahl nitrogen, ammonia nitrogen, and total soluble
salts. The remaining cores from both lagoons were composited
and analyzed for total solids. The analysis of each sample
was performed on the "as received" sample, and the results
were reported on a dry weight basis. A summary of the
results is presented in Table 5-1.
Discussion of Results
The lagoon deposits analyses vary significantly only in
respect to percent of solids. Lagoon 1 has an average
solids content of 12.9 percent while Lagoon 2 has 8.9 per-
cent. Since Lagoon 1 is closer to the discharge pipe and
has been used for 25 years longer so the higher average
solids content was expected. The solids contents measured
for the two lagoons agrees well with the 10-percent average
solids content estimated in the Weston report.
The ammonia nitrogen content of the lagoon sludge is much
lower than that of the treatment plant sludge. This can be
explained by the fact that ammonia is lost by volatilization
from the lagoon surface.
The cadmium to zinc ratio of the lagoon sludge is about
1.3 percent. This is slightly over the of 1.0 percent
recommended in the Federal Guidelines for sludge applied to
agricultural land. The cadmium to zinc ratio is also signi-
ficantly lower in the lagoon than in the treatment plant
sludge. Increased industrial discharge of cadmium in recent
years would explain why the treatment plant sludge has
higher cadmium content.
5-7
-------
r
0 300 600
SCALE IN FEET
NOTES:
1. SLUDGE DEPTHS AT LAGOON
PERIMETER ARE ESTIMATES.
2. DEPTHS ARE IN TERMS OF FEET.
FIGURE 5-3
SLUDGE DEPTHS
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
S9166.0
-------
TABLE 5-1
CHARACTERIZATION OF LAGOOM SLUDGE1'1
MADISON METROPOLITAN SEWERAGE DISTRICT
STATION
LAGOON 1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
MIN.
MAX
MEAN
LAGOON 2
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
MIN.
MAX.
MEAN
AVERAGE
DEPTH
OF
SLUDGE
Ift)
69
7 1
7 1
65
6.0
5.2
6 1
5.5
67
2.0
5.5
5.9
5.3
54
57
53
61
5.1
2.0
7 1
574
39
4.8
49
4,8
5.5
5.2
5.7
4.7
4.6
4.2
5.4
5.9
4.2
4,6
4.3
5.6
4.3
45
5.0
2.7
4.7
5.0
4.4
4.0
4 5
62
5.1
9.0
4.0
17.2
2.7
17.2
5.30
SULlUb I
TOTAL
SOLIDS
l%)
194
18.3
24.1
192
14 1
11 6
3 1
13.2
13.8
8.3
8.2
74
98
11 8
160
10.8
12.9
10.2
3.1
24 1
1290
97
8.6
9.3
12.7
10.3
9.0
7.2
8.9
7.8
11.8
67
5.9
10.0
7.7
8.2
4.5
8.7
7.5
8.0
9.9
42
5.0
5.7
10.5
7.0
4.6
10.8
6.8
107
4.2
12.7
8.20
-UN 1 tIM 1
VOLATILE
SOLIDS
(%)
98
98
CHARACTER
OF
LAGOON
SLUDGE
552
1055
98
PRIMARY NUTRIENTS
TOTAL NH4 TOTAL TOTAL
N N P K
(%) (%) (%) (%)
HEAVY METALS
Zn
mg/kg)
Cu
(mg/kg)
Cd
(mg/kg)
Ni
(mg/kg)
446
5.94
755
2.74
6.20
3.86
9.23
2.74
9.23
6.71
8.66
4.36
6.07
1 14 1 39
1.22
1.85
0.81
1.80
1 27
1.03
1.59
2.67
0.81
1 85
1.39
267
1.30 1 88
0.12 3,200 470
0.12 2,145 476
0.20 3,456 490
0.12 2,145 470
0.20 3,456 490
0.15 2,934 479
30 50
37.5 603
39.1 60.1
30.0 50.0
39.1 60.3
35.5 56.8
1.36
0.75
1.88
0.73
0.07
2,012
541
33.3
55.5
Ho
(mg/kg)
21 0
21.7
19.4
19.4
21.7
20.7
17.3
TOTAL
SOLUBLE
SALTS
as EC
(^mhos/cm)
2,670
4,010
4,430
2,670
4.430
3,703
3,590
4.16
6.91
1.15
1.81
0.16
0.31
2,080
259
459
25.3
50.7
26.9
2,740
4.730
6 16
4.16
8.66
5.98
0.50
0.50 0.73
1.88 1.41
1.16 1.07
1 23 1 4B
0.07
0.31
0.18
2,012 259
2,080 541
2,046 420
0165 2,490
450
25.3
33.3
29.3
324
50.7
55.5
53.1
17,3
26.9
22.1
214
2,740
4.730
3,687
(1) Analyses performed on an as-received composite of
entire core and results reported on a dry weight basis.
Exceptions are cores 2 and 36, in which the listed values
are an average for several individual segments
(2) Percent of sample volume
5-9
-------
Leaching of Lagoon Constituents
The presence of the sludge lagoon represents a potential
threat of ground-water contamination. To determine if this
threat is real, several core samples were selected for
detailed chemical profile tests. The sludge cores selected
were from Station 2 in Lagoon 1 and Station 36 in Lagoon 2.
Each of these sludge cores was then segmented into 4.5-inch
sections for analysis. In addition to the sludge samples,
deeper grab samples of peat and marl were collected with the
peat sampler at Stations 2 and 36 and also at the background
Stations N-1 and N-2 located in the uncontaminated marsh
north of the lagoons. Each of these samples was then ana-
lyzed for several selected chemical constituents, and the
results were plotted as a function of depth. Concentration
profile plots for four selected constituents for Lagoon 1
are presented on Figure 5-4. The profile plots for Lagoon 2
are presented on Figure 5-5. Additional plots for Lagoon 1
are included in Appendix A. The lagoon deposits were ana-
lyzed for tin, molybdenum, cobalt, and selenium, but none
were detected.
The results of these plots indicate that there is little or
no leaching of the sludge constituents past the first 1 foot
of the peat-soil layer. The concentration of constituents
typically reach a peak about midway through the sludge
blanket. The concentration is then rapidly reduced and
approaches the background concentration about 6 inches to
1 foot below the peat-sludge interface.
The potential for leaching of lagoon constituents through
the dikes was also evaluated. Hydrogeologic investigations
by Stephenson and Hennings (1972) indicate that seepage
losses through the dikes may be on the order of 0.001 to
0.01 cubic foot per second (cfs) on the perimeter of Lagoon 2.
This seepage water is very much diluted in the estimated
annual average flow in Nine Springs Creek of about 5.8 cfs.
The factor of dilution will be about 1 part seepage water in
600-6,000 parts watershed drainage water.
The District's program of monitoring the streams around the
lagoons also indicates that leaching of polluted water
through the dikes is not a problem. Two water quality
sampling stations have been established on Nine Springs
Creek; one upstream from the lagoons, the other downstream.
Monitoring of the ammonia content of the stream indicates
that there is no significant increase in ammonia as the
stream passes the lagoons.
5-10
-------
10 20 30 40
TOTAL SOLIDS (Percent)
TOTAL SOLIDS
500
1000
COPPER CONCENTRATION.
mg/kg (ppm)
COPPER
500
1000
1500
POTASSIUM CONCENTRATION,
mg/kg (ppm)
POTASSIUM
0 1000 2000 3000 4000
TOTAL SOLUBLE SALTS (EC)
JJmhos/cm
TOTAL SOLUBLE SALTS (EC)
LEGEND
• CORE SAMPLE NUMBER 2 FROM LAGOON 1
o CONTROL SAMPLE N-2 TAKEN OUTSIDE LAGOON
S9166.0
FIGURE 5-4
LAGOON 1
PHYSICAL AND CHEMICAL
DEPTH PROFILE
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
" -
5 10 15 20
TOTAL SOLIDS (Percent)
TOTAL SOLIDS
0 200 400 600 800
COPPER CONCENTRATION, mg/kg (ppm)
COPPER
0 600 1200 1800 2400
POTASSIUM CONCENTRATION, mg/kg (ppm)
POTASSIUM
1000 2000 3000 4000 5000
TOTAL SOLUBLE SALTS (EC) ^/mhos/cm
TOTAL SOLUBLE SALTS (EC)
LEGEND
• CORE SAMPLE NUMBER 36 FROM LAGOON 2
o CONTROL SAMPLE N-1 TAKEN OUTSIDE LAGOON
LS9166.0
FIGURE 5-5
LAGOON 2
PHYSICAL AND CHEMICAL
DEPTH PROFILE
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
Summary
TABLE 5-2
SUMMARY LAGOON ORGANIC SOLIDS
CHARACTER AND QUANTITY'
MADISON METROPOLITAN SEWERAGE DISTRICT
PARAMETER CONTENT
Quantity, tons dry solids 89,700
Total Solids, % 10.55
Nitrogen, % 5 84
Phosphorus, mg/kg 14,800
Potassium, mg/kg 1,650
Cadmium, mg/kg 324
Zinc, mg/kg 2,490
Copper, mg/kg 460
Nickel, mg/kg 55
Table 5-2 summarizes the
lagoon deposits character and
volume. The quantity may have
changed slightly since it was
measured in March 1975 because
sludge has been continuously
discharged into the lagoons
and the District has also
hauled some sludge to farmers.
'All results, except quantity and total solids,
are reported on a dry weight basis.
5.4 LAGOON EMBANKMENT EVALUATION
In July 1975, we presented a special report to MMSD entitled
Geotechnical Evaluation of Sludge Lagoon Embankments. This
report included a detailed discussion of the lagoon history
and physical conditions, past embankment failures, and past
geotechnical investigations. The existing condition of the
dikes was visually inspected by a geotechnical engineer from
CH2M HILL in April 1975. Based upon this inspection and the
results of previous investigations, a stability analysis was
performed. Alternatives for embankment stabilization were
prepared when it became evident that more dike failures were
imminent. Listed below are the major conclusions and recom-
mendations of the special report.
Conclusions
Relative to the sludge lagoon embankments, CH2M HILL's
visual inspection and evaluation of record information led
to the following conclusions:
• Certain reaches of the sludge lagoon embankments
are unstable.
• Failures and possible damaging spills are imminent,
and in the case of the south dike of Lagoon 2,
incipient.
• Regardless of the disposition of the sludge in the
lagoons, the unstable reaches must be repaired as
soon as possible.
5-13
-------
« The present method of sludge removal by dragline
from the dikes contributes to embankment stability
problems by removing counterweight (surcharge)
material.
Recommendations
CH2M HILL recommended that the Madison Metropolitan Sewerage
District take the following action:
• Stabilize the south dike of Lagoon 2 and portions
of the north and west dikes of Lagoon 2 as soon as
possible.
» Stabilize the reaches recommended by replacing the
existing dikes with embankments constructed by
corduroy and berm techniques.
• Terminate the present method of sludge removal as
soon as possible.
• Continue to return supernatant to the plant to
maintain freeboard.
• Adopt a schedule which would result in the dikes
being stabilized by July 1976.
In their meeting of 8 September 1975, the District accepted
the findings of the special report and decided to proceed
with the recommended dike stabilization program.
Later Investigations
In early 1976 test borings performed in the dike stabili-
zation program were used to provide data for detailed evalua-
tion of Lagoon 1 dikes. Engineering analysis using measured
soil strengths and compressibility indicated that the dikes
surrounding the westerly half of Lagoon 1 possess an adequate
factor of safety against failure and could continue to be
used as a sludge storage facility.
5.5 LAGOON ABANDONMENT
A program is required for abandoning the current method of
sludge disposal so that no lagoon contents will spill into
waters of the State. There are four general abandonment
options available.
5-14
-------
1. Treatment plant sludge; continue discharge to
existing lagoons or discontinue discharge and
bui Id new lagoons .
2. Lagoon sludge; remove and apply to farmland or
leave in lagoons.
3. Lagoon supernatant; remove and return to treatment
plant or leave in lagoons.
4. Lagoon dikes; stabilize and maintain or leave as
they are.
The four general abandonment options were each examined
separately. The cost estimating and calculating procedures
used in comparing lagoon abandonment alternatives and in
planning this sludge reuse program are discussed in Appen-
dix B.
Option I—Storage of Treatment Plant Sludge
The advantage of continuing discharge of treatment plant
sludge to the existing lagoons is that the facilities, the
pipeline and lagoons, already exist. If discharge to the
existing lagoons is discontinued, a new lagoon must be built
for sludge storage. Both options are viable, but continuing
discharge to the existing lagoons would be less costly than
building a new lagoon. Also, it would be difficult to
obtain a site for a large sludge storage facility. As will
be shown later in this report, the required seasonal sludge
storage capacity will be about 150 acre-feet. The estimated
cost to construct and acquire land for this lagoon is
$607,000. The detailed cost estimate for the new
150-acre-foot capacity sludge lagoon is presented in Table 1
of Appendix B.
Option 2--Removal of Lagoon Sludge
Two major factors regarding removal of the lagoon sludge are
removal methods and effects of leaving the sludge in the
lagoons.
Lagoon Sludge Removal. Several alternative sludge removal
methods, including those used by the District, were investi-
gated for technical feasibility, reliability, and costs. In
1973 and 1974, the District used a crane dragline to remove
lagoon solids for use on farmland when the lagoon began to
fi II to danger of dike fai lure. One dragline kept four
trucks busy and was able to remove about 100 dry tons of
lagoon deposits per day. This method of dragline cleaning
5-15
-------
costs about $3.55 per dry ton as determined by MMSD for
1974. Two problems with this method make it infeasible for
future use. First, we noted that the dragline bucket sinks
below the sludge and picks up peat from the lagoon bottom.
While this accomplishes storage volume recovery, it does not
fully accomplish sludge removal. Second, the operator is
able to swing the bucket out into the lagoon only 50-75 feet.
After once or twice around Lagoon 1 in 1974, the draglined
strip had filled with mostly treatment plant sludge because
the higher solids content sludge from the center of the
lagoons failed to flow toward the dikes. In order to con-
tinue this method of sludge removal, about 7.8 miles of
finger dikes, placed about 125 feet apart, would be required
to clean both lagoons. At an estimated $5.00 per lineal
foot, the finger dike construction would cost approximately
$205,000. Another problem with this method is that sludge
removal by dragline from the dikes contributes to embankment
stability problems by removing counterweight (surcharge)
material.
In August 1975, the District began using a small Sauerman
type dragline to drag sludge toward the dikes. This type of
dragline allowed the District to reach farther and minimize
dike stability problems. The sludge was then removed by
clamshell and loaded onto trucks. This method of dragging
the heavier solids toward the dikes appeared to be working
satisfactorily. They were able to increase their reach to
about 300 feet but still not enough to reach the middle of
the lagoons.
As an alternative to the dragline methods presently used, we
corresponded with Sauerman Bros, of Bellwood, Illinois, who
build large slackline cableway dragscrapers. This equipment
would operate from large stationary towers and drag lagoon
deposits toward the tower where it would be deposited at a
pump or conveyor. Due to the instability of the lagoon area
soils, considerable expense would be required to install
equipment of this type capable of cleaning the entire lagoon.
The cost of the extra foundation work alone would be an
estimated $50,000. The total cost of such a system would be
between $300,000 to $400,000. Experience with the small
dragline presently used indicates that the bucket tends to
sink through the liquid sludge to the bottom of the lagoon,
picking up some peat while leaving the more liquid sludge.
Another factor which also makes this type of equipment
infeasible is that it tends to remove dike counterweight
material, contributing to embankment instability. Due to
the high cost and poor technical feasibility, this system is
not suitable for the Nine Springs Lagoons.
5-16
-------
Use of stationary sludge or mud pumps in place of dragline
was also considered but felt to be unsatisfactory because
the high solids content deposits will not flow toward the
pump, and consequently, the pump would soon deplete its
source and have to be moved.
Other methods of lagoon deposits removal which were con-
sidered were by helicopter and by dewatering the lagoon. A
helicopter operation with bucket, as used to scoop water
from lakes and dump onto wildfires, was abandoned as being
too expensive. Dewatering by pumping with a pump located on
the dikes and then going in with loaders on pads to clean
out the remainder was also abandoned as being unproven.
MUD CAT ON NINE SPRINGS LAGOON
A small portable dredge which would slurry the sludge prior
to pumping is felt to be the most feasible method of cleaning
the lagoons. Mud Cat, manufactured by National Car Rental,
is a small floating dredge which is self-propelled and can
move into sludge to be pumped. A Mud Cat demonstration was
held on the Nine Springs Lagoons on 4 September 1975. The
machine demonstrated that it could pick up and pump 3 percent
solids sludge at a rate of 2,200 gallons per minute or
10 percent solids sludge at 700 gallons per minute. At a
pumping rate of 700 gallons per minute and operating effi-
ciency of 70 percent, about 900 8-hour days would be required
to remove the 210 million gallons of lagoon deposits. The
Mud Cat will require about 2 feet of liquid to float on for
maneuverability. Therefore, after removing sludge for a
time, water may need to be left in the lagoons to provide
flotation and improve discharge pipe maneuverability.
5-17
-------
The cost of cleaning the lagoons with a small floating
dredge like Mud Cat is estimated to be about $3.90 per ton
of dry solids or a present worth of $270,000. This includes
the capital costs of a dredge like Mud Cat, the pipeline to
a wet well, and a wet well. This does not include trans-
portation and land application of the sludge. The life of
the machine is expected to be 10 years. It is estimated
that it would remove an average of 10,000 tons of sludge per
year for 9 years. An extra year of operation was included
in the cost estimate to be used in slurrying the sludge and
to assist in weed mat removal. The cost estimates also
include the expense of applying a herbicide which would slow
weed growth and allow easier sludge removal. The development
of the cost estimates for lagoon sludge removal is detailed
in Appendix B, Table 2.
Other Considerations for Option 2. If the lagoons are
cleaned, the marsh could be allowed to return to its natural
state, and the threat of sludge spilling into the lakes
would be eliminated. If the sludge is left in the lagoons,
there would be no cost of removing the sludge, but since
supernatant and rainfall are expected to accumulate, there
would be the cost of returning this supernatant to the
treatment plant until it becomes nontoxic to fish. To
determine how long supernatant would have to be returned and
treated before it becomes nontoxic, a brief analysis was
made of the time required to dilute the ammonia-nitrogen
content of the lagoon supernatant with rainwater to the
level of 1.0 mg/l. This dilution analysis indicated that it
would take several hundred years. The reason for such a
long time is that ammonia nitrogen is continually mineralized
from the very large reservoir of organic nitrogen in the
sludge. Based upon this estimate, supernatant would have to
be pumped back every year. At the end of the planning
period of this study, the year 2000, very little improvement
would have been accomplished to the present lagoon situation.
The lagoons would still exist as a threat to the lakes, and
the supernatant quality will have improved very little.
Option 3—Lagoon Supernatant Removal
As stated earlier, it is anticipated that supernatant from
rain, snowfall, and sludge will accumulate in the lagoons.
If left to accumulate, the supernatant will overtop the
dikes. Since it is toxic to fish, it must not be allowed to
spill, but rather it must be returned to the treatment plant
for BOD and ammonia removal before discharge. At the present
time, the impact of the supernatant on the treatment process
5-18
-------
and the effluent is minimal. However, when the treatment
plant is upgraded to meet more stringent effluent standards,
the impact on the treatment process and effluent could be
significant.
Based on the discharge strategies currently under considera-
tion, it is highly probable that ammonia removal facilities
will be required to meet the required effluent quality. If
this is required, the ammonia content of the supernatant
will have the most impact on the treatment process design.
Under the present operation of the lagoons, sludge and
supernatant accumulate over the winter months. During this
period, there is minimal supernatant return due to ice cover
and there is also an increase in ammonia concentration also
due to ice cover.
12.000
FIGURE 5-6
IMPACT OF LAGOON SUPERNATANT ON
AMMONIA CONTENT OF
TREATMENT PLANT INFLUENT
MADISON METROPOLITAN SEWERAGE DISTRICT
MADISON, WISCONSIN
In the spring, shortly after
thaw, there is an urgent need
to pump the supernatant back
to the plant to avoid a spill
of supernatant over the dikes.
This pumping results in a
large flow ( 2 mgd) of super-
natant, very high in ammonia
( 250 mg/l), back to the
plant during April of each
year. As the season pro-
gresses, the flow and concen-
tration diminish very quickly;
however, the ammonia load to
the plant during April adds
another 65 percent to the
design ammonia load for the
treatment plant based on the
domestic contributions during
1980. The impact of the
supernatant ammonia load on
the plant design is illus-
trated on Figure 5-6.
As shown previously, if the
sludge is not removed from the
lagoons, the supernatant must
be returned and treated for
more than 100 years. If the
sludge is removed, the super-
natant must be handled for
about 10-15 years.
5-19
-------
Cost of Treating Supernatant. Several alternatives are
available for the removal of ammonia from the lagoon super-
natant. Due to the relatively small volume and high strength,
it can be effectively treated in a separate unit process.
This would relieve the treatment plant of a major seasonal
recycle load. On the other hand, if compatible, the super-
natant can be returned to the treatment plant and be treated
within the available capacity of the plant. The selected
mode of treatment is dependent on which one provides the
least cost of operation.
To provide a cost estimate for separate treatment, the
Ammonia Removal and Recovery Process (ARRP) was selected.
The ARRP is an ammonia stripping absorption process in which
ammonia is recovered as a byproduct that can be used as an
ammonia-based fertilizer. The ARRP has recently been applied
to only small, concentrated streams of ammonia such as
anaerobic digester supernatant and the ammonia-rich brine
produced in ion-exchange regeneration. The ARRP is sche-
matically shown on Figure 5-7.
A major factor to consider in the design of such a process
is that if the sludge rs not removed, there will be extra
freeboard on the lagoons to store the supernatant. The
supernatant treatment facilities must then be sized to
handle the very high peak ammonia concentration and flow
rate which occurs when the lagoons thaw in the spring as
shown on Figure 5-6. If sludge is removed from the lagoons,
freeboard will become available, and the supernatant treat-
ment facilities can be sized to handle a smaller load over a
longer duration. For this analysis, both cases were evalu-
ated.
The estimated present worth to construct and operate the
treatment facilities for the high peak load for 20 years is
$3,872,000. If some sludge is removed by 1981 so that
freeboard storage area is available, and if all sludge could
be removed, the facilities would have to treat lagoon super-
natant at a lower flow rate for only about 10 years. The
present worth in this case is estimated to be about
$1,469,000. The detailed costs of treating the supernatant
with the ARRP are presented in Table B-4 of Appendix B.
Cost estimates for treatment of the supernatant within the
plant were based on year-round nitrification utilizing the
rotating biological contactors. To achieve year-round
nitrification, it is necessary to design the nitrification
process to operate during the critical low temperature
winter months since the growth of nitrifying organisms is
5-20
-------
HIGH pH
INFLUENT
FAN (TYP.)
DUCTING (TYP.)
AMMONIA
LADEN GAS
STREAM
V-
GAS STREAM WITH '
AMMONIA REMOVED
EFFLUENT
RECYCLED
ABSORBENT
LIQUID
ACID AND WATER MAKEUP
AMMONIUM SALT
SLOWDOWN (LIQUID
OR SOLID). OR
DISCHARGE TO STEAM
STRIPPER FOR AMMONIA
GAS REMOVAL AND
RECOVERY
FIGURE 5-7
AMMONIA REMOVAL AND
RECOVERY PROCESS (ARRP)
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
S9166.0
-------
very temperature sensitive. At low temperatures, the growth
rate of nitrifiers is reduced substantially below that
observed at high temperatures. This requires additional
treatment capacity during the winter to accumulate the
volume of organisms required to achieve nitrification.
Therefore, since the system must achieve wintertime nitrifi-
cation, there is, in effect, additional unused capacity
during the warmer spring and summer months.
As shown on Figure 5-6, the supernatant is typically returned
to the plant during the spring months of April, May, and
June. Based on the temperature of the wastewater during
this period and the volume and strength of the supernatant,
it has been determined that the supernatant ammonia can be
treated within the unused warm weather capacity of the
proposed nitrification facility. This mode of operation
would not require any additional construction costs, but
there will be some operation and maintenance costs. These
costs include power to supply air to satisfy the oxygen
demands of the additional BOD and ammonia, power to pump the
supernatant back to the plant, maintenance of the pump, and
labor ot operate and maintain the pumping system. The
annual cost to treat supernatant in this manner is estimated
to be $33,800 per year as shown in Table B-4 of Appendix B.
The present worth of this annual cost over 10 years is
$250,000. If no lagoon sludge is removed, this cost would
probably occur over the next 100 years, in which case the
present worth would be $600,000. Based on the preceding
analysis and the cost comparison shown in Table B-4, it
appears most cost-effective to continue returning lagoon
supernatant to the treatment plant.
Option 4--Stabilization of Lagoon Dikes
As stated earlier, we have recommended stabilization of the
existing dikes. These recommendations are based on findings
of our special report to the commissioners, Geotechnical
Evaluation of Sludge Lagoon Embankments. In developing our
recommendations, we considered the options of doing nothing
which might result in an accidental spill on breaching the
dikes and causing a spill. Under these options, it was
presumed that it would be more economical to replant a fish
kill than to invest large sums of money in embankment
stabilization or lagoon cleanout. However, if the sludge
was released, it would introduce oxygen-depleting organics,
taste and odor producing constituents, toxic substances and
heavy metal ions, release tremendous amounts of nutrients,
increase the color and turbidity, increase suspended and
dissolved solids, and introduce potentially pathogenic
wastes to the receiving waters. The environmental conse-
quences would be manifested by the deposition of sludge beds
5-22
-------
in streams, the stimulation of excessive growths of weeds
and algae, particularly attached algae, deterioration of
water quality, the killing and prohibition of the existence
of certain species offish and aquatic life, and the devalu-
ation of the aesthetic and recreational values of the affected
waters.
Causing or allowing the lagoon deposits to enter the streams
and lakes would also be contrary to the purpose and success
of the present diversion of sewage effluent and wastes
around the Madison lakes to retard lake degradation. Allowing
the lagoon deposits to enter the lakes and streams would
eliminate the past accomplishments in improving the water
quality of the lower Madison lakes. In the event of a
spill, replanting fish alone will not be sufficient in
restoring any ecological balance. The excessive algae
growth will become so luxuriant that chemical treatment and
mechanical aquatic plant harvesting would be necessitated.
And finally, the public's displeasure over the condition of
a polluted Lake Waubesa and Kegonsa may bring legal action
against the parties reponsible.
Based upon the preceding analysis and the dike investigations
presented in the special report, the dikes should be stabi-
lized as soon as possible to prevent continued failures.
5.6 ALTERNATIVE ABANDONMENT PROGRAMS
Based on the foregoing examination of the options available,
the following abandonment programs were considered to be
environmentally sound and were investigated and compared to
select the most feasible.
1. Discontinue discharging sludge to lagoon and build
a new lagoon, do not remove the sludge, return
supernatant until it becomes nontoxic.
2. Discontinue discharging sludge to lagoon and build
a new lagoon, remove sludge, return supernatant
until it becomes nontoxic.
3. Continue discharging sludge to a portion of existing
lagoon, remove sludge, return supernatant.
Common requirements of each alternative abandonment program
are that the dikes be maintained or stabilized and super-
natant be returned. Dike stabilization has been implemented,
and the cost and effects will be the same for each alterna-
tive.
5-23
-------
Abandonment Program 1
Abandonment Program 1 consists of discontinuing discharge of
sludge to the lagoons, leaving the sludge in the lagoons,
and returning the supernatant for treatment.
The main advantage of this alternative stems from the stipu-
lation that the sludge would not be removed from the lagoons.
This would save the expense of handling the sludge and the
need to find land on which to apply it.
However, this abandonment program has several disadvantages.
A new storage lagoon would be needed. This would require
major construction and acquisition of land, which is a major
problem in itself. People simply do not want a "sewage
lagoon" located near them and would oppose and delay construc-
tion. The concept of farmers accepting sludge for agricul-
tural reuse requires favorable farm community attitudes
which may be lost in areas near a new large sludge lagoon.
Another disadvantage of Abandonment Program 1 is that the
sludge filled lagoons will continue to be a source of odor
and will remain a potential source of contaminants to the
surrounding swamp and waterways.
Lagoon Abandonment Program 1 will have three major costs.
One will be the direct cost of stabilizing and maintaining
the dikes. This will be a continual periodic cost lasting
for the more than 100 years estimated necessary for the
lagoons to naturally return to an environmentally safe
condition. Another major expense would be the cost of
returning the supernatant to the treatment plant and making
it safe for discharge. The construction and operation of
supernatant treatment facilities for 20 years has an esti-
mated present worth of $430,000 as shown in discussion of
Option 3. A major indirect expense would be the cost of
land acquisition for and construction of a new storage
lagoon. This was estimated to cost $607,000.
Abandonment Program 2
Abandonment Program 2 consists of discontinuing discharge of
sludge to the lagoons, removing the sludge, and returning
the supernatant for treatment.
Removing sludge from the lagoons will cause some temporary
environmental disturbances, but these will be outweighed by
the overall improvement of the lagoon situation.
The major environmental disturbances from the sludge removal
action would be noise, dust, and odors. The lagoons' appear-
ance now approaches that of the surrounding marsh in summer
5-24
-------
with lush plant growth in the lagoons and on the dikes.
Removal of the sludge would change the lagoon appearance
back to that of a sludge lagoon with the black liquid sludge
readily apparent. After the cleanout operation was completed
and the lagoons left to return to a natural state, they
would again take the appearance of the surrounding marsh.
Removing sludge from the lagoons will lessen the degree, and
may even eliminate potential environmental hazards presently
existing from the lagoon deposits.
In abiding by the MMSD Commission's resolution to dispose of
sludge on land, the sludge removed from the lagoons should
be applied to land. It would be most practical to remove
sludge from the lagoons at the same rate at which it could
be applied to farmland rather than all at once. This would
eliminate intermediate handling and construction of another
large lagoon for the lagoon deposits; however, a small
lagoon will be required for seasonal storage of the treatment
plant sludge as in Abandonment Program 1.
The allowable rates of land application of sludge are
discussed in Chapter 6. The annual lagoon sludge application
rate is about 3.0 tons dry solids per acre. The total
allowable sludge application can be about 120 tons sludge
per acre. If a single parcel of land is to accept all of
the sludge at a rate of 3.0 tons per acre per year, the
application would have to be spread out over 40 years. This
is not a suitable method due to the long time requirement.
If all of the sludge were removed in 1 year and applied to
land at the rate of 3.0 tons per acre, 30,000 acres of land
would be required. This also is not suitable since it would
be infeasible to obtain the use of such a large amount of
land and not practical to gear up for such a large sludge
handling operation for a single year.
The time frame for removal of the sludge from the lagoons
depends upon the amount of land available for sludge applica-
tion. An analysis of farmer acceptance of sludge is included
in Chapter 6. Based upon that analysis, it is expected that
enough farmers will want sludge that the District could
empty the lagoons in 8-14 years. Net removal of sludge from
the lagoons cannot begin until more than enough land becomes
available for reuse of the treatment plant sludge. Due to
the expected gradual farmer acceptance of sludge reuse,
1-3 years may be required before a full lagoon cleanout
operation could be started. With the above time frames for
lagoon cleanout, the sludge removal method must be capable
of removing between 7,000-14,000 dry tons per year. A rate
of 10,000 dry tons per year, for 9 years, was used as a
basis of comparing the lagoon abandonment programs .
5-25
-------
After the lagoon is cleaned out, the annual precipitation
into the lagoon may accumulate. This supernatant should be
monitored, and if found to be of good quality, be allowed to
drain into the marsh. If not of good quality, it should be
collected and pumped back to the treatment plant. Achieving
good quality supernatant depends upon how well the sludge is
cleaned from the lagoon and how much of the precipitation
and nutrients weeds will use.
The time expected for the supernatant to become nontoxic is,
in any case, much less than if the lagoons were not cleaned
out; and when it does become nontoxic, the treatment plant
will be relieved of a major contaminant recycle stream.
Several factors must be investigated at the time the lagoons
are emptied to determine the supernatant quality required
for drainage into the marsh. This would include a determin-
ation of the amount of runoff from the lagoon area and the
effect of various water quality parameters on the creek and
lake environment. A preliminary analysis indicates that a
supernatant with 8 mg/l of ammonia could be discharged to
Nine Springs Creek with a resultant increase in the present
average ammonia concentration from 0.5-0.6 mg/l. If the
creek ammonia concentration is allowed to be increased to
1.0 mg/l, the supernatant ammonia concentration could be
38 mg/l.
Lagoon Abandonment Program 2 will have the major costs of
stabilizing and maintaining the dikes for 10-15 years, the
cost of removing the sludge from the lagoons, $270,000; the
problems and costs of building a new treatment plant sludge
storage lagoon, $607,000; and the cost of returning the
supernatant to the plant and treating it for 10 years,
$210,000. The cost of transporting and applying the sludge
to farmland must also be considered. At an estimated $25.00
per dry ton, this would be $2,250,000.
Abandonment Program 3
Abandonment Program 3 consists of continuing discharge of
sludge to the lagoons, removing sludge from the lagoons, and
returning the supernatant for treatment.
This program is different from Program 2 only in that MMSD
would use the west half of Lagoon 1 for seasonal storage and
aging of the treatment plant sludge. This would eliminate
the need to construct another storage lagoon. The sludge in
the remaining half of Lagoon 1 and all of Lagoon 2 would be
removed.
5-26
-------
The environmental impacts at Nine Springs Marsh of this
abandonment program would be greater than for Program 2,
because a portion of the area would continue to be used for
seasonal sludge storage. However, the overall environmental
impacts will be the same because Program 2 will require
construction of a similarly sized lagoon elsewhere. Also,
the time period for cleaning the lagoons would be the same
as for Program 2. A major economic advantage of this program
over Programs 1 and 2 is that the District would not need to
construct a new lagoon to store the treatment plant sludge
in periods when it cannot be applied to land.
A Mud Cat or similar device, as described earlier, is also
recommended for lagoon sludge removal in this program. It
would be required to handle the treatment plant sludge in
addition to the lagoon deposits. The major cost items of
Program 3 would be dike stabilization and maintenance,
lagoon sludge removal, $270,000; construction of a dike
across Lagoon 1 to form the seasonal storage lagoon,
$234,000; supernatant return and treatment, $211,000; and
transporation and land application of the sludge,
$2,250,000. The costs and basis for construction of a
seasonal storage lagoon in Lagoon 1 are given in Table B-3
of Appendix B.
Comparison of Lagoon Abandonment Programs
Table 5-3 lists a comparison of the three abandonment pro-
grams. They are compared on the basis of potential for
sludge spill and environmental damage and dike stabilization
and maintenance requirements. They are also compared on the
basis of the costs of providing sludge storage, removing
sludge from the lagoons, reusing the sludge, and returning
and treating the supernatant. Based on the economic compar-
ison, Program 1 would be best because it has the lowest
cost, followed by Program 3, and with Program 2 having the
greatest cost. However, Program 1 has a lasting potential
for severe environmental degradation in the event of a dike
failure. Also, the costs of continually maintaining the
dikes, which were not included in Table 5-3 because they
could not be reasonably estimated, could reduce or eliminate
the economic advantage of Program 1. Therefore, Lagoon
Abandonment Program 3 is recommended for implementation.
5.7 RECOMMENDED LAGOON ABANDONMENT PROGRAM
General Description
The recommended program consists of removing all sludge from
Lagoon 2 and from approximately the east half of Lagoon 1.
Treatment plant sludge will be discharged to the west
5-27
-------
TABLE 5-3
COMPARISON OF LAGOON ABANDONMENT PROGRAMS
MADISON METROPOLITAN SEWERAGE DISTRICT
Description
PROGRAM 1
Discontinue sludge
discharge to lagoons,
do not remove sludge,
return supernatant
Potential for Sludge Lasting Potential
Spill and Environ-
mental Damage
Dike Stabilization
and Maintenances
Seasonal Sludge
Storage
Construction Cost
Land Acquisition
Costd)
For over 100 years
Build new lagoon
111 $ 607,000
23,000
PROGRAM 2
Discontinue sludge
discharge to lagoons,
remove sludge, return
supernatant.
None after lagoons
emptied
For about 15 years
Build new lagoon
$ 607,000
23,000
PROGRAM 3
Continue sludge discharge
to lagoon, remove sludge,
return supernatant
None after lagoons
emptied.
For about 15 years
Use west half of Lagoon 1
after about 1984
$ 136.000
0
Sludge Removal
Cos,'1'
Sludge Reuse
Con'1'
Return and Treat
Supernatant
Cost'"
None removed
0
Not reused
0
For over 100 years
$ 430,000
Less Value of Sludge121 0
Total Present Worth
Total Comparative
Annual Cost* '
111 $1.060,000
$ 92,500
Remove all
$ 270,000
Applied to land
$2.250,000
For about 10 years
$ 211,000
$1,350,000
$2,011,000
$ 175,500
Remove all
$ 270,000
Applied to land
$2,250,000
For about 10 years
$ 211.000
$1.350,000
$1,517,000
$ 132,000
(1) These costs are the present worth on January 1.
(976 of capital, operation, and maintenance costs
incurred during the study period.
(2) Value of sludge is $1500 per dry ton.
(3) Total present worth amortized over the study period.
half of Lagoon 1 when required for storage. All of the
treatment plant sludge may be aged in the lagoons before
agricultural reuse. The lagoon sludge and treatment plant
sludge will be removed and applied to farmland as required
to meet farmer demand. The supernatant in the lagoons will
be returned to the Nine Springs Plant for treatment and
discharge whenever it begins to accumulate to an unsafe
depth. The lagoon dikes will be stabilized in the ongoing
rehabilitation program. The dikes must be maintained for
about 15 years or as long as there is sludge or toxic
supernatant in the lagoons.
Implementation
Sludge Removal. Lagoon 2 should be cleaned first because
its dikes are the most unstable. Some sludge should also be
removed from Lagoon 1 each year to keep from overtopping the
dikes. It is likely that there will not be a net removal of
sludge from the lagoons in at least the first year, and
possibly the first 3 years, because the market for sludge
5-28
-------
will take some time to develop. The first years should be
utilized to break up or remove the thick mat of weeds which
now covers the lagoons. A herbicide could be used to slow
or stop weed growth on the lagoons to make weed mat removal
easier. This should be done on small areas so that the weed
mat is removed or broken up before the weeds can become
reestablished. The herbicide could be applied from the
floating dredge, from a small boat, or from the dikes. The
herbicide manufacturer's recommended procedures for use
should be followed closely to prevent damage to the marsh
surrounding the lagoons. The sludge removal dredge with
weed-cutter attachment could chew up and slurry the weed
mat. The contents should also be slurried; otherwise, the
more liquid portion would be removed first, leaving behind
the heavier consistency sludge. If a Mud Cat type of dredge
is used, it may be necessary to leave water in the lagoons
to provide flotation and increase its mobility when the
lagoons are nearly cleaned.
Supernatant Handling. The District must continue removing
supernatant when they can. Once some freeboard is obtained
by sludge removal, trie supernatant return could be spread
out over spring through fall, rather than at a high peak
rate after the spring lagoon ice thaw. After several years
of sludge removal, the supernatant might possibly be mixed
in with the lagoon deposits and handled with the sludge
applied to farmland.
Equipment Requirements. We recommend that MMSD purchase one
standard Model MC-10 Mud Cat, or equivalent, to remove
sludge from the lagoon. One machine operating about 100 days
per year could remove 10,000 tons of lagoon sludge. This
would leave at least another 100 days per year to handle
treatment plant sludge. During peak sludge use periods, two
or three 8-hour shifts may be required each day.
Several appurtenances which should be purchased with the
dredge are float-supported pipeline, a small rowboat to
provide transportation to the dredge, and pipeline to trans-
port the sludge to a wet well. A wet well should be con-
structed with its top no higher than the dike top into which
the dredge can discharge the sludge. The wet well should be
low so that the dredge pumping rate would not be reduced.
The sludge would be pumped into a loading dock, into trucks,
or through a pipeline to farmland from the wet well. Two
men will be required for the lagoon cleanout operation: one
to operate the dredge and the other to move the pipe and
guide cables.
5-29
-------
Seasonal Sludge Storage Lagoon. A dike should be constructed
across Lagoon 1 to form a storage area in the west half with
a capacity of about 150 acre-feet. The remainder of Lagoon 1
would be allowed to return to a natural state like the
surrounding marsh. This work should not be done until
Lagoon 1 is partially empty in order to minimize construction
problems. Also, Lagoon 1 can serve as the seasonal sludge
storage area until the dike is built in about 1984. The
storage capacity requirement should be refined at that time,
based upon experience of operating the sludge reuse program.
Detailed investigations of the embankment foundation should
also be performed at that time as the basis for designing
and building the new dike section.
Lagoon Cleanout Schedule. An estimated total of about
10 years will be required to remove all the sludge from the
lagoons. This allows 1 year for weed mat removal and 9 years
to remove the estimated 89,700 dry tons of sludge at a rate
of 10,000 dry tons per year. A major unpredictable variable
which could change the time required is the farm community
demand for sludge.
Program Cost. The estimated total present worth to remove
the sludge from the lagoons and apply it to land, and to
provide seasonal storage for the treatment plant sludge is
$1,517,000. This estimate includes the following: con-
struction of a dike across Lagoon 1, removal of sludge from
the lagoon, agricultural reuse of the sludge, treatment of
the supernatant, and the value of the sludge as a fertilizer.
On a unit basis, the cost is about $16.90 per dry ton.
Accomplishments. This abandonment program would end the
disposal of sludge in the Nine Springs Marsh and protect the
streams and lakes from a sludge spill. The estimated
89,700 tons of lagoon sludge, estimated to have a fertilizer
value of about $15.00 per ton, or $1.35 million total, would
be made available for agricultural reuse. Also, most of the
existing lagoon area would be returned to a natural condi-
tion, and seasonal treatment plant sludge storage would be
provided. We believe this plan will meet the WDNR directives
asking for abandonment of the present method of sludge
disposal.
5.8 SUMMARY
The quantity and quality of the sludge in the Nine Springs
Lagoons were determined by extensive field sampling and
laboratory analyses. The depth of sludge in the 135 acres
of lagoons ranges generally from 2-7.1 feet in Lagoon 1 and
3.9-6.2 feet in Lagoon 2. The percent dry solids content
5-30
-------
averages 12.9 and 8.2 in Lagoons 1 and 2, respectively. The
total sludge quantity in the lagoons was calculated to be
89,700 dry tons.
The quality of the lagoon sludge, as shown in Table 5-1,
indicates its suitability for agricultural reuse. The
sludge sampling investigation included gathering samples of
the underlying peat and marl to determine leaching of sludge
constituents and indicated that there is little or no
leaching past the first 1 foot of the peat-soil layer.
The condition of the lagoon embankments was studied in
detail and a special report was presented to MMSD which
concluded that failures and possible sludge spills are
imminent and recommended that the dikes be stabilized. The
District has proceeded with the recommended dike stabiliza-
tion program.
A program for abandonment of the present method of sludge
disposal in the Nine Springs Lagoons was prepared as required
by the Wisconsin Department of Natural Resources. The
recommended program consists of removing all sludge from
Lagoon 2 and from approximately the east half of Lagoon 1.
The west half of Lagoon 1 will be used for seasonal storage
of the treatment plant sludge. The estimated present worth
to remove the sludge from the lagoons and to provide seasonal
storage for the treatment plant sludge is $1,517,000, or
about $16.90 per dry ton.
5-31
-------
6.1 STUDY AREA DESCRIPTION
6.2 REGULATIONS
6.3 SLUDGE APPLICATION RATE DEVELOPMENT
6.4 OTHER CONSIDERATIONS FOR AGRICULTURAL REUSE
6.5 SLUDGE APPLICATION SITE INVESTIGATION
6.6 SUMMARY
CONSIDERATIONS FOR
AGRICULTURAL REUSE OF SLUDGE
-------
Chapter 6
CONSIDERATIONS FOR AGRICULTURAL REUSE OF SLUDGE
This chapter discusses the study area, regulations regarding
land application of sludge, sludge application rates, appli-
cation sites, and other considerations for agricultural
reuse of sludge. All of these factors must be investigated
to ensure that the reuse program is acceptable to the public,
that it is environmentally safe, and that the sludge will be
successfully recycled into agriculture.
6.1 STUDY AREA DESCRIPTION
A study area consisting of the land within a 10-mile radius
of the Nine Springs Sewage Treatment Works was delineated as
a basis for discussion. This study area is located within
Dane County, mostly south of Madison. It consists of about
91,000 acres of farmland and could accept all of the MMSD
sludge for many years to come.
Agriculture
The major crops grown in the study area are field corn,
40,000 acres; small grains (including oats, barley, and
wheat), 5,600 acres; and alfalfa, 15,000 acres. The field
corn consists of about 75 percent grain corn and 25 percent
silage corn. Other crops commonly grown include soybeans,
potatoes, tobacco, processing peas, sweet corn, hay other
than alfalfa, and pasture or greenchop grass and legumes.
There are approximately 550 farms in the study area, covering
91,000 acres or about 165 acres each (Wisconsin Statistical
Reporting Service, 1974).
Dane County ranks high in agricultural production in Wiscon-
sin. In 1973 Dane County led production in grain corn,
silage corn, alfalfa hay; and was a major producer of pro-
cessing peas, livestock and dairy products. Dane County's
outstanding agricultural production is further emphasized by
Wisconsin's No. 1 nationwide ranking in production of dairy
cattle, milk, cheese, corn silage, all hay, and green peas
for processing (Walters 1974). The grain crops are fed to
the farmer's own cattle or sold on grain markets. The dairy
cattle are increasingly kept on feedlots. Forage is either
in the form of dried hay or greenchop rather than pasture.
The weather and prices paid for crops play a very important
part in determining the types and amounts of crops planted.
A late wet spring, for instance, may cause substitution of
the types of crops planted.
6-1
-------
Climate
TABLE 6-1
NORMAL STUDY AREA TEMPERATURE
AND PRECIPITATION'
MADISON METROPOLITAN SEWERAGE DISTRICT
TEMPERATURE
MONTH (°F)
January
February
March
April
May
June
July
August
September
October
November
December
YEAR
175
195
291
444
56 1
66 1
71 1
695
61 0
499
340
22 1
450
PRECIPITATION
(inches)
1 40
1 13
1.84
257
334
395
358
337
332
221
2 14
1 31
30 16
Data are standard normals (1931-1960) for Madison,
Wisconsin, Truax Field, gathered and reported by
U S Department of Commerce Weather Bureau
The study area climate is
typically midwestern with most
of the precipitation coming in
summer when crops need it
most. The area climate is
also affected by the Great
Lakes (Wisconsin Statistical
Reporting Service 1967) . Few
areas are irrigated and most
rely on natural precipitation
to supply the crop water
requirements. Many areas
suffer some minor effects of
drought most years, but the
advantages of irrigation do
not offset the cost. The
monthly normal temperature and
precipitation are listed in
Table 6-1.
The summer months are charac-
terized as being hot and muggy
with frequent thunderstorms,
whereas winters are cold and
relatively dry . Normally, the
ground is frozen from mid-December through mid-March, with
the frost depth reaching below 20 inches at times. The
ground is often snow covered from December through mid-March
(Wisconsin Statistical Reporting Service 1970) .
Ground Water
Geology. The strata from which Dane County obtains its
ground-water supply are sandstones, dolomites, and shales of
Cambrian and Ordovician ages and sand and gravel deposits of
Quaternary age. The Cambrian rocks, which are the major
source of water and the overlying dolomite of the Prairie du
Chien Group of Ordovician age, were deposited in a shallow
sea environment. Following a long period of emergence,
erosion, and then submergence, the remaining rocks of
Ordovician age were deposited. Subsequent uplift and
erosion has left an irregular bedrock surface having a
maximum relief of about 1,000 feet.
In the more recent Pleistocene time, glaciers moved across
the eastern two-thirds of the county from northeast to
southwest, transporting large quantities of rock debris
6-2
-------
frozen in the ice. This unconsolidated material (drift) was
dumped on the land surface by the melting glaciers, and thus
formed the present day surface that contains glacial features
and that is poorly drained.
Glacial drift covers most of the bedrock except in the
westerly one-third of Dane County. In this area, glacial
outwash deposits and Recent alluvial deposits occur in the
valleys. In addition, this area is thinly blanketed by
loess (Cline 1965).
Occurrence. Ground water occurs under water-table and
artesian conditions in Dane County. Glacial till partially
confines ground water in many places in the eastern two-
thirds of the county, whereas water-table conditions prevail
in the western part of the county. Ground water in the
sandstones of Cambrian age generally is partially confined.
Permeability of rocks and movement of ground water in Dane
County are generally greater parallel to than perpendicular
to the rock's bedding. Rock strata having low permeability—
such as clay, shale, and dolomite—retard the vertical
movement of water. Rock fractures or joints provide paths
for ground-water movement in the less permeable rocks or
zones.
Vertical movement of water through the St. Peter Sandstone
is generally good, except in the basal part where shale and
poorly sorted material retard the movement of water. In
places where the St. Peter Sandstone rests directly on the
Cambrian rocks, circulation of ground water between the two
units is more rapid than in places where the Prairie du
Chien Group is present.
Circulation of water through the Plattevilie-Galena unit is
poor and occurs principally through fractures and solution
channels.
The outwash and alluvium are generally excellent sources of
ground water and yield small to large quantities of water.
Ground-water movement through outwash and alluvium is gen-
erally good as well as the circulation between the outwash
and alluvium and adjacent bedrock.
Ground water moves through the principal aquifers from areas
of recharge to points of discharge, such as springs, streams,
lakes, wells, and drainage ditches. The direction of ground-
water movement in the deep aquifers is shown by arrows on
Figure 6-1. The arrows run normal to lines of equal ele-
6-3
-------
vation on the piezometric surface, which is the surface to
which water will rise if the aquifer below the confining
layer is tapped. Locally, where there are no confining
layers, the piezometric surface is representative of the
water table surface.
The direction of ground-water movement is nearly coincident
with the direction of surface drainage. Generally, this
will indicate a gain in streamflow due to ground-water
seepage into the stream. Conversely, when the direction of
ground-water movement runs across the surface drainage there
will be a loss from stream flow.
Ground-water movement under natural conditions is extremely
slow. As shown on Figure 6-1, the effective velocity of
ground-water movement within the deeper aquifers ranges
between about 0.04 feet per day and 3.1 feet per day, the
difference in velocity being attributable to differences in
rock permeabilities and hydraulic gradient.
Quality. The ground water in Dane County is for the most
part of excellent chemical quality. Generally, the ground
water quality is poor only where man has added a pollutant.
One report (Holt and Skinner 1973) listed the results of
water quality measurements taken in many municipal and
private wells. Of 106 wells tested for dissolved solids,
only six were above the 500 mg/l limit for drinking water
recommended by the U.S. Public Health Service (USPHS). Of
84 wells tested for nitrate, three had levels above 45 mg/l
which is the safe limit suggested by the USPHS. The source
of the high concentration of nitrogen appears to be local-
ized contamination from feedlots and other manure sources
(Water Resources Task Group 1971) . Improper wastewater and
sludge disposal and excess fertilizer applications may also
cause a buildup of ground-water nitrate. Since the study
area ground water is generally safe for drinking, the sludge
reuse program must be designed to protect the ground water
from contamination.
Land Use
The majority of the land in the study area is used for
agriculture. However, the area is being encroached upon by
many housing developments, with some developments approach-
ing a quarter section in size. The area also contains, or
is bordered by, the villages of Oregon, Stoughton, McFarland,
Brooklyn, and Verona. There are several large marshes in
the study area which can be used only for wildlife and
recreation.
6-4
-------
_a*>"
SCALE IN MILES
LEGEND
PIEZOMETRIC SURFACE
CONTOUR LINE AND
ELEVATION (FEET)
APRIL -MAY 1960
GROUND WATER FLOW
LINE AND VELOCITY
(FEET/DAY)
FIGURE 6-1
GROUND WATER
PIEZOMETRIC SURFACE AND
FLOW DIRECTIONS
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
\S9166.0
-------
6.2 REGULATIONS
Local, state, and Federal regulations regarding distribution
and application to land of liquid sewage sludge were investi-
gated to ensure that the recommended reuse program conforms
to all applicable requirements and guidelines.
Local Regulations
Applicable local regulatory agencies in the study area were
contacted for regulations regarding land application of
sludge. The agencies and persons contacted consisted of the
following: Dane County Regional Planning Commission, Dane
County Zoning Administrator, City of Madison Environmental
Health Public Health Department, City of Madison City Plan-
ning, City of Monona Clerk, Village of Verona Clerk, Village
of Brooklyn Clerk, Village of Belleville Clerk, Village of
Oregon Clerk, City of Stoughton Clerk, Village of Cottage
Grove Clerk, and City of Middleton Clerk. This investigation
indicated that the various agencies would rely on the state
requirements for sludge application to land.
State Regulations
The Wisconsin Department of Natural Resources (WDNR) has
recently prepared "Guidelines for the Application of Waste-
water Sludge to Agricultural Land in Wisconsin," Technical
Bulletin No. 88, dated 1975. This report provides working
guidelines which may be revised as new information becomes
available in the future. This report is one of the most
comprehensive of its kind in the United States. It will be
used to assist WDNR personnel in granting discharge permits.
The WDNR guidelines contain detailed explanations of methods
to determine acceptable annual and total sludge application
rates. It also contains guidelines for program management
and operation and site selection. The following list is a
summary of recommendations from the WDNR guidelines:
• Raw sludge should not be applied to agricultural
land.
• Sludges should be applied to soils consistent with
the nitrogen needs of the crops being grown.
• At least 2 feet and preferably greater than 4 feet
of soil should exist between the sludge application
zone and bedrock, any impermeable layer, or the
water table.
6-6
-------
• Sludge should not be applied to soil in the year
the area is used for any root crops or other
vegetables which are consumed uncooked.
• If sludge is surface applied to sloping land,
runoff should be minimized by use of contour
strips, terraces and border areas. Also, runoff
can be reduced by injection or immediate incorpor-
ation of the sludge.
• Pasture land (or crops which are harvested green)
should not be used for milk cow feeding for 2 months
following sludge application. Other animals
should not graze pasture land or be fed greenchop
material for at least 2 weeks after sludge applica-
tion.
• Metal loadings must be kept within acceptable
limits to minimize the potential of crop damage or
food chain accumulation. The soil pH must be
maintained at 6.5 or greater.
• Application systems must be such that they minimize
the runoff potential and odor problems while
remaining cost-effective.
• Sludge application sites should be at least 500
feet from the nearest residence. If the sludge is
injected or incorporated into the soil, a reduction
in this distance may be possible.
• Site management must be such that nutrient defi-
ciency and soil acidity problems do not occur,
public access is limited, and crop yields are
maximized.
• Site monitoring should be the responsibility of
the municipality. If sludge additions consistent
with nitrogen requirements are used, monitoring
needs include only sludge and plant analyses as
well as routine soil testing. If higher rates, on
dedicated land, are used, comprehensive ground-
water monitoring must be included.
• To ensure adequate protection of water supplies,
the sludge application site should be a minimum of
1,000 feet from the nearest public water supply
well and 500 feet from the nearest private water
supply well.
6-7
-------
The last list item which recommends a 500-foot radius (18
acres) buffer area around all private water supply wells may
be too stringent. In the study area, where most farm homes
will have a private well, this requirement alone will prevent
sludge application on about 15 percent of the area. This
will also create an inconvenience for the farmer in that he
would need to use an alternate fertilizer method in the
large buffer area. Section NR 112.07 (k) of the Wisconsin
Administrative Code on Well Construction and Pump Installa-
tion Standards and Related Information, by WDNR, requires
200 feet between any well and any sludge disposal area if
that well is used to supply ground water for human consump-
tion or for preparation of food products. We have recommended
a 200-foot buffer radius and periodic ground-water monitoring
for nitrates.
Federal Regulations
The U.S. Environmental Protection Agency (U.S. EPA) is
completing a supplement to be entitled, "Municipal Sludge
Management; Environmental Factors" to the Federal Guidelines:
Design, Operation, and Maintenance of Wastewater Treatment
Facilities, which includes guidelines for land application
of sludge. The U.S. EPA guidelines, which must be used by
Federal grant applicants, are summarized in the following
list:
• The sludge nutrient value, heavy metals and other
constituents which may economically recycle or
cause environmental damage should be determined.
• The site soils should be tested for cation exchange
capacity (C.E.C.), pH, and background heavy metals.
• The soils and ground-water conditions should be
investigated at each site.
• Sludge must be stabilized before land application.
• Pathogen reduction may be required in some projects.
• The suitabi lity of the crop for sludge amended
soils must be determined.
• The project should be designed so that ground
water will be protected from pollution.
• Surface water runoff must be controlled.
6-8
-------
• The annual application rate must be such that the
amount of plant available nitrogen added is not
greater than twice the nitrogen requirement of the
crop.
» The grant applicant must show the capability to
manage and operate the system.
« The grant applicant must develop and implement a
monitoring program. The monitoring data must be
periodically reviewed.
• The sludge heavy metal additions calculated as
zinc equivalent must not exceed 10 percent of the
CEC of the unsludged soi I.
•" The soil pH must be maintained at 6. 5 or greater
for a period of at least 2 years after sludge
application.
• Sludge having a cadmium content greater than
1 percent of its zinc content should not be applied
to cropland except under certain specified con-
ditions.
*• Special precautions should be taken when sludge is
applied to pasture.
• The facility plans should be reviewed by the U.S.
Department of Agriculture (USDA) and Food and Drug
Administration (FDA).
« Products in the human food chain grown on sludge
amended land should be monitored for heavy metals,
persistent organics, and pathogens.
6.3 SLUDGE APPLICATION RATE DEVELOPMENT
Three major factors are required to determine sludge appli-
cation rates. These are the sludge characteristics, the
soil suitability for sludge application, and the types of
crops grown. The character of the treatment plant sludge
and the lagoon deposits were reported in Chapters 4 and 5.
Soil Suitability for Sludge Application
Seven soil parameters; erosion hazard, depth to ground
water, depth to bedrock, flood hazard, soil texture, soil
permeability, and cation exchange capacity were investigated
6-9
-------
to determine soil suitability for sludge application. Each
parameter was given a point rating. The ratings were then
combined to classify each soil series and phase. The source
of information was the interim soil survey for Dane County
titled, Soil Interpretations, A Guide to Land Use and Conser-
vation Planning, by the Soil Conservation Service (SCS),
1970.
Erosion Hazard. Soil erosion is a potential source of
pollution through runoff and sediment loading of surface
waterways. Soil erodibility was evaluated and each soil
assigned an erosion hazard of none, slight, moderate, or
severe from values calculated from known K (soil erodibility
factor) and T (permissible soil loss, ton per acre per
year) . The K and T factors are listed for each soil in the
interim soil survey. The Universal Soil Loss equation was
used to calculate the estimated soil loss in tons per acre
per year. In addition to the known K value, this equation
considers the variables (L) length of slope, (S) slope
gradient, (C) cropping management, (P) erosion protection
practices, and (R) rainfall index where A (soil loss) = K x
LxSxCxPxR. Values for L, S, C, P, and R were taken
from USDA Handbook 282 and information supplied by the State
SCS Agronomist in Madison.
The estimated soil loss in tons per acre per year was calcu-
lated by assuming several values for each variable. These A
values were compared to the individual T (permissible soil
loss) value for each soil. Each soil was assigned an erosion
hazard classification point rating according to the following:
No erosion hazard 1.00
Slight erosion hazard .90
Moderate erosion hazard .80
Severe erosion hazard .60
Slopes greater than 12% were given a zero (unsuitable)
rating. A particular soil may show more than one erosion
hazard rating as a result of a difference in management
conditions.
Depth to Ground Water. A fluctuating water table may cause
a flushing action on the chemical constituents and increase
weathering within the soil profile. Any soil with a seasonal
high-water table within 3 feet of the surface was eliminated
by a zero rating due to possible ground-water contamination
from nitrates and soluble salts. The DNR guidelines suggest
at least 2 feet and preferably 4 feet to ground water.
Three feet is used here because the soils are mapped for
either 3 or 5 feet rather than 4 feet. Setting the limit at
6-10
-------
5 feet would be too restrictive for the study area. The
soils were evaluated and given a point rating for depth to
ground water as follows:
>5 feet 1.00
3-5 feet .70
<3 feet 0
Depth to Bedrock. The soil has a finite capacity to absorb
heavy metals, store nutrients for plant uptake, and hold
pathogens until they are biologically inert. The deeper the
soil, the greater the soil mass for removal of possible
pollutants. Shallow soils over bedrock, or other imperme-
able layer, have a seriously reduced ability to remove
possible sources of pollution; therefore, any soil with
bedrock within 3.5 feet of the surface was eliminated by a
zero rating. All other soils were evaluated and given a
point rating according to the depth to bedrock as follows:
>5 feet 1.00
3.5-5 feet .45
<3.5 feet 0
The DNR guidelines suggest at least 2 feet and preferably
4 feet to bedrock or other impermeable layer. This depth is
mapped mostly according to 20, 40, or 60 inches in Dane
County. Therefore, 40 inches, 3.5 feet, was used as the
cutoff point.
Flood Hazard. Soils that are subject to frequent flooding
were eliminated due to possible pollution hazards. Pathogens,
heavy metals, and sediments may be introduced into surface
waters from soils that are flooded. A point rating was
assigned according to the flood frequency as follows:
None 1.00
Rare (less than once in
20 years) .80
Occasional (less than once
in 5 years) . 40
Frequent (more than once
in 5 years) 0
Soil Texture and Permeability. Texture and permeability are
two closely related soil characteristics that must be con-
sidered in an evaluation of the soil. Both characteristics
are important in determining the movement of moisture and
nutrients into and through the soil profile. With sludge
applications on sandy soils, there is concern about the
6-11
-------
rapid movement of nitrates and other potential pollutants
into the ground water. With fine-textured soils, there is
concern about slow water movement and the possibility of
surface runoff or ponding.
The soil textures are grouped in accordance with USDA Soil
Taxonomy textural classes with the control section generally
from 10-40 inches. Contrasting textural classes within the
control section are indicated. Soil textures were evaluated
and given a point rating as follows:
Fine loamy or fine silty .90-1.00
Loamy .70-1.00
Fine (clayey) .80- .95
Coarse loamy or coarse
silty .70- .90
Sandy (sands) .65- ,85
Sandy (skeletal) .50- .70
A variable point rating has been established because in
certain textural classes, particle size percentages are
grouped within a specified range; i.e., coarse loamy contains
less than 18 percent clay and more than 15 percent sand.
Soil permeabilities are listed by USDA permeability classes
in inches per hour. Soil permeabilities were evaluated and
given a point rating according to the following:
Slow (0.06-0.2 in.hr) .80
Moderately Slow (0.2-0.6 in./hr) .95
Moderate (0.6-2.0 9n./hr) 1.00
Moderately Rapid (2.0-6.0 in./hr) .95
Rapid (6.0-2.0 in./hr) .85
Cation Exchange Capacity. Cation exchange capacity (CEC) is
a measure of the soil's ability to exchange and adsorb
cations, thereby reducing the cation mobility within the
soil. This soil characteristic is important in determining
the heavy metal loading rates for each soil.
Cation exchange information was obtained from USDA-SCS Soil
Survey Investigations Report No. 17, Wisconsin; No. 19,
Illinois; and No. 18, Indiana. CEC information from soils
in adjoining states is assumed to be valid for the same
series mapped in Wisconsin. Additional pertinent infor-
mation was provided by Dr. Leo Walsh of the University of
Wisconsin, Madison.
6-12
-------
Soils were grouped by soil taxonomic classification so that
similar soils could be assigned comparable CEC when no other
information was available. Soils were evaluated and given a
point rating according to their CEC as follows:
>16 meq/100 grams 1.00
10-16 meq/100 grams .80
6-10 meq/100 grams .60
4-6 meq/100 grams .40
<4 meq/100 grams .20
Computations. A numerical rating from 0 to 1.00 was computed
for each soil series and phase by multiplying all individual
item points together. The suitability classification for
sludge application was prepared based on the following
numerical rating system:
Class 1 .66-1.00
Class 2 .35- .65
Class 3 .01- .34
Class 4 0
Class 1 soils are the most suitable for sludge application.
Class 2 soils are suitable with minor limitations. Class 3
soils should be used only if enough Class 1 and 2 soil areas
are not available. Class 4 soils are not suitable for
sludge application.
Summary of Suitability Classes. The properties and suit-
ability for sludge application of the Dane County soils are
summarized in Appendix C. Class 1 soils have ground water
at a depth of more than 5 feet, bedrock at 5 feet or more,
no flood hazard, and a cation exchange capacity equal to or
greater than 15 meq/100 grams.
Many of the Class 2 soils are the steeper phases of the
Class 1 soils with at least one additional major limitation.
Most of these soils have a combination of limitations which
are not severe enough to place them in a lower class. All
of the Class 2 soils have bedrock at greater than 5 feet
depth and ground water at greater than 3 feet depth.
The Class 3 soils often represent steeper phases of Class 1
and 2 soils with additional major limitations. All but four
of the Class 3 soils have bedrock at greater than 5 feet.
The four that have bedrock at 3. 5 to 5 feet have ground
water at greater than 5 feet.
6-13
-------
Class 4 soils have major limitations making them unsuitable
for sludge application. Any soil factor evaluated with a
zero rating places the soil into Class 4.
A comparison of this suitability classification with the
Wisconsin DNR guidelines shows the following: Class 1 and
Class 2 are equivalent to soils having slight limitations;
Class 3 soils are similar to soils with moderate
limitations; and Class 4 soils correspond to soils having
moderate to severe limitations. This soil suitability
classification system is very restrictive. Of over 200 soil
series and phases investigated, only 83 were placed in
suitability Classes 1 and 2.
Crop Suitability for Sludge Application
Dane County crops were studied to determine their annual
nitrogen fertilizer requirement, cultural practices, and
their use. The annual nitrogen requirement is important in
determining the annual sludge application rate. The crop
type and use is important in determining the allowable
method, time, and total quantity of sludge application. The
planting and harvesting dates and restrictions for sludge
use on common Dane County crops are shown in Table 6-2.
TABLE 6-2
CROP PLANTING AND HARVESTING DATES AND
RESTRICTIONS FOR SLUDGE REUSE
MADISON METROPOLITAN SEWERAGE DISTRICT
CROP
Grain Corn
Silage Corn
Small Grains
Spring
Winter
Soybeans
Sweet Corn
Processing Peas
Tobacco
Vegetables c'ooked
before consumption
Vegetables eaten
raw
Alfalfa
Forage Grasses
PLANTED
May
May
Apr:
, Sept.
Mav
May
Apr.
May
Apr -June
HARVESTED
late Sept.-Nov.
Aug.-Sept
Aug.
Aug.-Sept.
late June
July-Sept
July-Sept
Apr -June July-Sept
Perennial
Perennial
* General restrictions apply to all crops
-------
TABLE 6-3
ANNUAL FERTILIZER REQUIREMENTS
(pounds of element per acre)
MADISON METROPOLITAN SEWERAGE DISTRICT
NITROGEN PHOSPHORUS POTASSIUM
CROP
Grain Corn
Silage Corn
Oats
Barley
Rye
Wheat
Sorghum
Soybeans
Alfalfa
Pasture
Processing Peas
Sweet Corn
Tobacco
Potatoes
Other Vegetables
NITROGE1
125
175
35
35
35
35
100
5'
o-
75
5*
75
100
160
100-200
35
35
20
20
20
20
40
20
35
25
20
35
40
85
15-60
40
40
50
50
50
50
160
50
400
50
50
40
75
160
130-250
'Legumes can get most of their nitrogen from the air,
but thev will also use soil nitrogen when readily
available.
Fertilizer requirements for
crops grown in the study are
shown in Table 6-3. These
values are based upon general
literature and discussions
with local agricultural exten-
sion personnel. The fertili-
zer requirements vary from
field to field and from year
to year in a single field
depending upon natural soil
fertility, past cropping and
fertilizer applications, and
crop management. The ferti-
lizer values in Table 6-3 are
meant only to be used as a
basis of determining general
study area sludge application
rates.
Annual Sludge Application
Limits
NOTE' The crops are listed with their planting and
harvest dates and restrictions for sludge reuse
in Table 6-2 The local crop management
practices were determined by discussions with
Dane County Agricultural Extension personnel
and local farmers.
In general, the annual sludge
application rates will be
limited by the nitrogen appli-
cation rate. If the amount of
applied nitrogen that becomes available to crops is greater
than that which the crop can use, the excess could be leached
into the ground water where it could be a health hazard.
Ideally, the applied nitrogen which becomes available to the
crop should equal the crop nitrogen requirement. Not all of
the nitrogen in the sludge is available to crops in the year
it is applied. Most nitrogen used by crops is in the nitrate
form. Since the nitrogen in the sludge is mainly in the
ammonia and organic forms, it must be converted or miner-
alized into the nitrate form which crops can use.
Ammonia nitrogen is rapidly mineralized. It is estimated
that about 90 percent of the applied ammonia nitrogen which
is not lost by volatilization will become available in the
year applied. The remainder should become available in the
second year. The amount of ammonia nitrogen lost by volati-
zation to the atmosphere will depend upon the method of
application to land.
The organic nitrogen requires a longer period for minerali-
zation. It is estimated that about 20 percent of the applied
organic nitrogen will become available to plants in the year
6-15
-------
it is applied. In the second year, 6 percent of the
remaining organic nitrogen should become available. In the
third year, about 4 percent will become available. In the
fourth year and each year thereafter, about 2 percent of the
remaining soil organic nitrogen should become available to
plants. These organic nitrogen mineralization rates are
based upon University of Wisconsin research (Walsh 1975) .
The annual sludge application rates will vary for the treat-
ment plant and lagoon sludges because the nitrogen contents,
especially ammonia nitrogen, are different. The annual
application rates required to achieve a certain amount of
available nitrogen must be reduced to allow for the miner-
alization of organic nitrogen applied in previous years.
The yearly decrease in the treatment plant and lagoon sludge
annual application rates are shown on Figures 6-2 and
6-3. The treatment plant sludge annual application rates
could change considerably depending upon future plant oper-
ation.
FIGURE 6-2
ANNUAL TREATMENT PLANT SLUDGE
APPLICATION RATES FOR DIFFERENT
AVAILABLE NITROGEN REQUIREMENTS
MADISON METROPOLITAN SEWERAGE DISTRICT
MADISON, WISCONSIN
The annual sludge application rate for Class 3 soils should
be reduced by one-third because the soils in this class are
generally less capable of supporting crops which could
utilize a full nitrogen application. These less suitable
soils also may have shallow depths to ground water and
bedrock. Reducing the annual sludge application is recom-
mended as an added precaution against ground-water pol-
lution.
6-16
-------
:, VEAM
FIGURE 6-3
ANNUAL LAGOON SLUDGE
APPLICATION RATES FOR DIFFERENT
AVAILABLE NITROGEN REQUIREMENTS
MADISON METROPOLITAN SEWERAGE DISTRICT
MADISON, WISCONSIN
The WDNR guidelines for sludge reuse recommends limiting the
annual cadmium (Cd) application to 2 pounds per acre per year.
For the treatment plant sludge, the annual application is
limited by Cd to 14 tons per acre per year. Cadmium limits
the lagoon sludge annual application to 31 tons/acre/year.
Nitrogen will control the annual sludge application rates
because it is more limiting than cadmium.
Total Sludge Application Limits
The limits set for total sludge application are based upon
constituents which accumulate in the soil. Heavy metals
will generally be the limiting constituents.
6-17
-------
Heavy Metals. Heavy metals have been shown to be phytotoxic
to crops when applied to soil in large amounts. Heavy
metals, when accumulated in plants, may also be toxic to
humans and animals (Page 1974). If the metals are retained
in the soil, unavailable for uptake by roots, they will not
be a problem. The mechanisms which cause soil retention of
heavy metals are numerous, complex, and interrelated. The
sludge application rates recommended are conservative, based
upon the best information currently available.
Several empirical methods have been used to estimate total
safe metal loadings. The "zinc equivalent" method, developed
in England and recommended by U.S. EPA and WDNR guidelines,
limits the total metal loading calculated as "zinc equiva-
lent" to 10 percent of the soil cation exchange capacity.
This limits the combined zinc, copper, and nickel additions
below phytotoxic levels. The equation used to compute total
allowable sludge application is
_ . . . 32,700 x CEC
I otai siuage ppm Zn+2 (ppm Cu)+4(ppm Ni)
Total sludge - tons dry solids/acre
CEC - cation exchange capacity of the unsludged soil
in meq/100 g
ppm - mg/kg dry wt. of sludge
The calculated allowable total application rates for the
treatment plant and lagoon sludges both equal about 140 tons
for Class 1 soils, 90 tons for Class 2 soils, and 60 tons
dry solids per acre for the Class 3 soils. These were
computed using CEC's of 15, 10, and 6 meq/100 g, respectively.
The WDNR guidelines suggest limiting the total cadmium
application to less than 20 pounds per acre because of
potential health hazards. This is based in part upon the
research performed by the University of Wisconsin. For the
treatment plant sludge, this equals about 137 tons of sludge
per acre. For the lagoon sludge, this equals 308 tons of
sludge per acre.
There are other heavy metals which may also be of concern.
As yet no standards have been developed for these based upon
sludge application. The University of California, however,
has developed guidelines for irrigation water quality criteria
(Ayers and Branson 1975). Using this, the allowable loading
rates were computed for metals other than zinc, copper,
nickel, and cadmium. This method bases the total loading
rate for individual heavy metals on the amount which would
be applied with 3 acre-feet per acre of irrigation water
6-18
-------
each year for 20 years at the limiting quality criteria.
Table 6-4 lists the sludge application limits imposed by
metals other than Zn, Cu, Ni, and Cd. According to this
method, iron may be a problem with lagoon sludge applica-
tions over 120 tons dry solids per acre.
TABLE 6-4
TOTAL SLUDGE APPLICATION BASED ON
IRRIGATION WATER QUALITY CRITERIA
MADISON METROPOLITAN SEWERAGE DISTRICT
CONCENTRATION IN SLUDGE WATER OUALTIV CRITERIA SLUDGE APPLICATION LIMIT
QUANTITY TREATMENT
ELEMENT
Aluminum
Arsenic
Boron
Chromium
Cobalt
TREATMENT CONCEN- IN
PLANT LAGOONS TRATION 60 AC.-FT.
Manganese
tmg/kg)
2.870
14
300
234
30
8.850
286
189
(mg/kg)
5,850
11
75
200
ND
13,980
520
350
(me/1)
20.0
2.0
20
1 0
50
200
100
100
(Ib/acl
3,260
326
326
163
816
3.260
1,630
1.630
PLANT
SLUDGE
Iton/ac)
570
11,600
543
348
13,600
184
2.850
4310
LAGOON
SLUDGE
(ton/ae)
279
14,800
2,170
408
116
1,570
2.330
ND means not detectable
Mercury was investigated individually because it accumulates
in animals and can be toxic. Plants are not very sensitive
to mercury and exclude it at the soil-root interface.
Therefore, at the low sludge application rates we have
recommended it should not accumulate in the plants or be
magnified in the food chain.
Phosphorus. Ground water is usually protected from phos-
phorus contamination because soil has a very high degree of
retention capacity for phosphorus. However, the phosphorus
fixating capacity is limited and must not be exceeded.
Methods for estimating the phosphorus sorption capacity are
now being developed. When perfected, these procedures could
be used for site evaluation (Ellis 1973 and Schneider and
Erickson 1972). Meanwhile, the total phosphorus applica-
tion should be limited to about 5,000 pounds per acre, or
180 dry tons sludge per acre.
Salts. The dissolved salts in the sludge should not cause
salinity problems to crops. The major study area field
crops, corn, grain, and alfalfa are tolerant of soil satur-
ation extract salt content (ECe) of about 3.3, 4.7, and 2.0
mmhos/cm of salt, respectively (Ayers and Branson 1975).
More than 26 tons per acre of treatment plant sludge and 230
6-19
-------
230 tons per acre lagoon sludge would be required to
increase the ECe of the soil by even 1 mmho/cm. The total
salts in the sludge will not contribute to soil salinity
since over time, some salts will be precipitated, others
will be removed by crops, and still others will be leached
below the root zone. Ammonium salts, for example, will be
nitrified and over a period of time be consumed by plants or
be lost by leaching or denitrification. If it is assumed
that half of the applied salts do not contribute to soil
salinity and that the soil is now low in salts, over 170
tons of sludge could be added over a period of several years
with no detrimental accumulation of salts in the soil. Salt
accumulation in soils is easily monitored and therefore
controlled with good sludge reuse management.
Total Sludge Application Rates Summary. The total sludge
application rates based upon the zinc equivalent, cadmium,
water quality, phosphorus, and salts were compared to deter-
mine recommended rates. The total recommended treatment
plant sludge application is 140 tons per acre for Class 1
soils. This corresponds to the limits set by both the zinc
equivalent and cadmium criteria. The recommended total for
lagoon sludge on Class 1 soils is 120 tons per acre. This
is due to the iron limitation as determined by the irrigation
water quality criteria. The water quality criteria were
determined for the arid west where the soils are seldom, if
ever, flushed out by excess water moving through the soil as
they are in the midwest. Therefore, the irrigation water
quality criteria are very conservative for Madison. The
total recommended sludge application for the Class 2 soils
is 90 tons per acre as determined by the zinc equivalent
method. The total recommended sludge application limit for
the soil Class 3 should be 60 tons per acre as determined by
the zinc equivalent method.
The total sludge applications should be reduced by at least
one-quarter for all direct human consumption vegetables such
as processing peas and sweet corn. The total loading should
be reduced for land which will be used for leaf vegetables,
such as lettuce, by one-half because cadmium tends to
accumulate in the leaves.
Summary of Sludge Application Rates
The annual and total sludge application rates according to
soil class and crop type are shown in Tables 6-5 and 6-6
for the treatment plant sludge and the lagoon sludge, respec-
tively.
6-20
-------
SOIL
121 12)
VEGETABLES
TABLE 6-5
TREATMENT PLANT ORGANIC SOLIDS ANNUAL AND
TOTAL APPLICATION RATES"! ACCORDING TO
SOIL CLASS AND CROP TYPE
(tons dry solidi p« «cf«)
MADISON METROPOLITAN SEWERAGE DISTRICT
ANNUAL AVAILABLE NITROGEN REQUIREMENT db/ac)
35 50 75 75 100 125 150 175 200
250
PROCESSING SMALL
CLASS LEAF ROOT SOYBEANS PEAS GRAINS
1 121/70 (31/105 0.05/140 005/105 03/140 04/140
SWEET GRAIN
FORAGE GRASS CORN TOBACCO CORN
SILAGE
CORN
0 6/140
0.6/105 09/105 11/140 13/140 15/140 17/140 21/140
2 (2l/45 (3j,70 Q05/90 005/70 03/90 0.4/90
0.6/90
0.6/70 09/90 11/90 13/90 15/90 17/90 21/90
I2'/30 (3l/45 003/60 003/45 0.2/60 0.3/60
04/60
04/45 06/45 07/60 0.9/60 10/60 11/60 14/60
NONE NONE NONE
NONE
NONE NONE
NONE
NONE NONE NONE NONE NONE NONE NONE
(1) Application rates shown as annual/total, annual rate shown for first year applicaton
Rates shown are for sludge which has not been aged.
(2) Wide variation in annual nitrogen requirements.
(3) Waste organics should not be applied in year crop is grown.
TABLE 6-6
LAGOON ORGANIC SOLIDS ANNUAL AND TOTAL APPLICATION RATES'"
ACCORDING TO SOIL CLASS AND CROP TYPE
(tons dry solids per acre)
MADISON METROPOLITAN SEWERAGE DISTRICT
VEGETABLES
ANNUAL AVAILABLE NITROGEN REQUIREMENT llta/ac)
35
50
SOIL veuEi«DLE» PROCESSING SMALL
CLASS LEAF ROOT SOYBEANS PEAS GRAINS
I2:/60 I3'/90 01/120
0.1/90
09/120 1.3/120
75
75
100
125 150
SWEET GRAIN
FORAGE GRASS CORN TOBACCO CORN
1 9/120
SILAGE
CORN
200
19/90 26/120 31/120 37/150 44/120 50/120 62120
2 121/45 I3I/70 01/90 0.1/70 0.9/90 1.3/90
1.9/90
1.9/70 2 5/90 31/90 3.7/90 44/90 50/90 62/90
"/30 ' ,'45 006/60 006/45 0.6/60 0.9/60
1.3/45 17/60 21/60 25/60 29/60 3360 4 1'60
NONE NONE NONE
NONE NONE NONE
NONE
NONE NONE NONE NONE NONE NONE NONE
0) Applicaton rates shown as annual/total, annual rate shown for first year application
(2) Wide variation in annual nitrogen requirements.
(3) Sludge should not be applied m year crop is grown.
6-21
-------
The application rate values shown in Tables 6-5 and 6-6 are
presented as an estimate and should not be used until
verified in the field. The CEC of the unsludged soil and
the other factors used to determine the soil classification
should be checked on each site before sludge is applied.
The annual application rates will vary because the cropping
patterns will change and because soil organic matter will
also change, depending upon site management. The total
application rate will be determined by monitoring each site.
The sludge character, which has a direct influence upon
application rates, may change and must be monitored also.
The loading rate tables presented will be used as the basis
of land requirements for this report.
6.4 OTHER CONSIDERATIONS FOR AGRICULTURAL REUSE
Fertilizer Market
The fertilizer market situation will have great impact upon
how willing the farm community is to accept sludge as a
substitute for commercial fertilizers. The fertilizer
industry has recently experienced a shortage of the natural
resources and energy necessary to produce fertilizers while
the demand for fertilizer has grown tremendously in certain
areas of the country. These factors have resulted in greatly
increased prices for nitrogen and phosphorus fertilizers all
across the United States.
In Wisconsin, about 594,000 tons of fertilizer mixtures and
materials were used in the year ended June 30, 1965. By
1972, seven years later, fertilizer use had grown to 942,000
tons per year. About 11,300 tons of natural organic ferti-
lizers were sold in 1972 (Crop Reporting Board, USDA 1973).
With the high prices of fertilizers, farmers have reduced
their use of commercial fertilizer somewhat and have begun
to use available natural organic sources. As long as the
fertilizer prices stay high, the farm community is expected
to use natural organics, including sludge, as lower cost
nutrient sources. The decreased use of fertilizer has
resulted in some increase in fertilizer producers' inven-
tories in the last year. Supply should not be as great a
problem in the next few years as it has been in the recent
past (Chemical Week, August 1975), but natural resources and
energy shortages are expected to keep prices high.
Reuse of sludge should have little impact on the commercial
fertilizer market in the Madison area. It is estimated that
the Nine Springs Sewage Treatment Works sludge could supply
6-22
-------
only about 3 percent of the study area nitrogen requirement.
This should assure a high demand because of the apparent
limited supply.
Farm Community Acceptance of Sludge Reuse
It was necessary to estimate the number of farmers which
will want to use sludge to determine if a program based upon
farmers wanting sludge will succeed. Two public meetings,
to which the farm community was invited, were held to deter-
mine their interest in the program. These meetings were
also used to inform the farmers about the requirements of
sludge reuse and to show them how sludge can be used and
applied and how the program could operate. Feedback from
the farmers was used in developing the reuse program wher-
ever possible.
Eighteen farmers, representing about 3,000 acres, who attended
the meetings and returned questionnaires, all said they
would use sludge. Several want it as soon as they can get
it. Based upon MMSD records on those who have already used
sludge and the results of a MMSD letter and questionnaire
sent to farmers on 2 August 1974, there are now about 26
farmers, representing about 5,000 acres, who apparently are
willing to use sludge. The District has also been approached
by several other farmers in the area who want sludge. Based
upon the preceding, the District already has a strong poten-
tial market for sludge reuse represented by more than 5,000
acres of land.
Land Ownership
The farmland in the study area is presently about 80 percent
owner operated and 20 percent leased. The trend is toward
fewer, larger landowners and operators. Small farms simply
are not large enough for most efficient and economical
operation. Many small farms (less than 100 acres) are
leased to persons operating combined areas of over 100 acres.
The cost of farmland in the study area has been rising
rapidly in the last year. It now varies from about $700 per
acre for medium to poor land several miles from cities up to
$2,500 per acre in areas under pressure of subdivision and
land speculation. This cost includes the value of improve-
ments such as the farmhouse, barns, and fencing. The cost
of leasing or renting farmland is normally about $50 per
acre per year.
Public ownership of the land required for sludge application
would be a distinct advantage to the District because it
6-23
-------
would then be assured of a place to apply the sludge. The
land availability would not be affected by public attitudes
or variations in the economy as could happen if the sludge
is applied on privately controlled farmland. However,
private ownership has several advantages which, in this
case, outweigh public ownership.
Acquisition of several hundred or thousand acres of land by
the District would be a major institutional and economic
problem. Many families would need to be displaced from land
that in many cases may have been in the family for genera-
tions. Long and expensive condemnation proceedings would
most likely be required if MMSD were to attempt to purchase
any large land areas for sludge application. Neighbors to a
large sludge application site would most likely complain
about environmental conditions, whereas relatively small,
widespread sludge reuse areas in private ownership would
cause much less concern by neighbors to the sites.
Other problems of public ownership are that a public insti-
tution would become engaged in the production of crops for
competitive markets, and the land could be removed from the
tax rolls. The adverse effects of these factors could be
minimized if the farming operation were leased to a local
farmer and if the District elected to make a payment in lieu
of taxes.
The cost to the District to own and operate an application
site would be very high; about $1,250 to $1,600 per acre or
$21 to $26 per dry ton of sludge applied. This is the
present worth cost of owning and operating an application
site for 20 years. The analysis considered the cost of the
land; taxes or payment in lieu of; cost of condemnation;
potential revenue from the crops; the salvage value at the
end of the 20-year operating period, and the potential
savings in transporting, applying and monitoring the sludge
at a District-owned site.
A similar analysis was performed for the marketing alterna-
tive (see Section 7.2). The estimated cost to the District
to operate this type of program is expected to range from
$500 to $1,200 per acre, or $8 to $20 per dry ton of sludge
applied. The high range assumes no revenue from the sale of
sludge, and the low range assumes receiving revenue equal to
one-half its value as a commercial fertilizer.
6-24
-------
Sludge Application Periods
Several factors will control the periods during which sludge
can be applied to land. These include cultural practices,
crop growth stages, weather, application equipment capabil-
ities, and animal and human health protection.
Cultural Practices. Sludge application should not interfere
with cultural practices. Certain practices must generally
be performed at specific times to maximize crop production
and to minimize farming expenses. Sludge application should
be scheduled around seedbed preparation, planting, harvest,
and fertilizer, herbicide, and pesticide application. These
cultural practices vary from crop to crop and year to year.
Crop Growth Stages. Crops go through several growth stages
where sludge application could be detrimental. Liquid
sludge is high in soluble salts which may inhibit seed
germination. Therefore, sludge must not, in general, be
applied within 2 weeks before or after planting. If the
soil is dry, the required buffer period may be more than
2 weeks to allow sufficient time for the soluble salts to
dissipate before planting. Sludge should not be applied to
crop foliage within 2 weeks before or after the pollination
period to prevent washing off pollen or disturbing pollen-
carrying insects. Application on growing plants could
result in injury to the leaves. Application in fall could
result in less efficient nitrogen use due to denitrification
or nitrate leaching.
Weather. The weather in Dane County is a significant factor
which must be considered in sludge application. The climate
is typically midwestern with much of the precipitation
falling during the summer. Sludge should not be applied
onto saturated or frozen sloping ground because subsequent
precipitation or thawing could cause surface runoff. The
ground is generally frozen from about mid-December to mid-
March .
Equipment. The time of sludge application will be limited
to that which the application equipment can effectively
operate without causing rutting or excessive soil compaction.
Heavy equipment such as trucks or farm tractors are not
usable while the ground is wet and soft. Subsurface injec-
tion is not usable in wet, hard, or frozen soil.
Health. To protect the public and animal health in use of
the crop, sludge must be applied so that it will not contam-
inate the harvested portions of the crop. In general,
6-25
-------
sludge must not be applied within 1 month before harvest.
Rains will wash sludge from the crop but cannot always be
depended upon. Sludge must not be applied to pasture or
forage crops within 2 months before the crop is grazed or
harvested. The major method of dairy cow feeding in the
study area is greenchopping and hauling it to feed lots.
This is performed about every 5 weeks, so sludge application
on greenchop land will not be permitted during the summer
months. Crazing animals should not be allowed on pasture
until the sludge is removed from the plant by rain or other
method; this can be determined visually. The minimum time
between sludge application and feeding should be 2 weeks for
general livestock. Sludge should not be applied to land
used to grow vegetables within the calendar year before
harvest.
TABLE 6-7 The foregoing factors affecting the
ESTIMATED MONTHLY DISTRIBUTION OF time of sludge application were
SLUDGE USE ON PRIVATE FARMLAND considered for each croo nrown in
MADISON METROPOLITAN SEWERAGE DISTRICT conbioerea TUT edt.n <_rup grown m
the study area. Based on the
PERCENT OF period of sludge application for
MONTH ANNUAL TOTAL each crop , and the re I ati ve amount
°0 of sludge applied to each crop, an
o overall monthly distribution of
M^V" 15 sludge application on private
June 10 farmland was determined and is
A^ust 5 shown in Table 6-7.
September 10
October 15
November 10 Soi I Wetting Effect of S ludge
December 0
The time required for soil to dry
is important to a farmer who is
waiting to plant his crops in the spring. The amount of water
applied with a 3-ton-solids per acre sludge application is
about 0.5 inch depth. This amount of moisture is not a
significant problem in drying the soil. However, if the
sludge is spread on the surface and not then incorporated
into the soil, a film may form which can delay soil drying
time considerably. University of Wisconsin researchers have
noticed that the time for a soil to dry with sludge applied
can be about twice as long as required where an equivalent
amount of water was applied. Therefore, whenever soil
wetness could be a problem, the sludge should be incorporated
into the soil directly after spreading or at least harrowed
and broken up when dried sludge film forms.
6-26
-------
Odors
Well-digested liquid sewage sludge will emit a faint tar-
like odor immediately after application which is not objec-
tionable to most people and which dissipates rapidly. When
air dried, sludge has an earthy odor. The odors caused by
well-digested sludge can be minimized or made undetectable
by subsurface application or incorporation into the soil.
Incompletely digested sludge or sludge from an upset digester,
however, can be very malodorous and should not be applied to
land. It should first be stored or treated to reduce the
odor.
The odors experienced by passersby or neighbors to the land
application site should be less than the magnitude of odor
caused by manure spreading. The fact that it is sewage
sludge, though, may cause them to imagine that the odor is
stronger or more offensive than manure. Where complaints
have been received, or could be in the future, such as near
major roads or subdivisions, the sludge odor should be
minimized by applying only by subsurface methods or when it
can be incorporated into the soil within 2 days. The wind
direction while surface applying should also be considered
and application be made only while adverse effect would be
minimized.
Insects
Flies and other nuisance insects can be a problem if careful
management is not used. Sludge which has been lagooned will
have fewer insect problems because it is more stabilized
than fresh digested sludge. Insects should not be a problem
where good housekeeping is practiced. Sludge handling
equipment should be kept clean, and spillage onto roads,
into ditches, etc., must not be allowed. Liquid sludge
should not be allowed to drain into low wet spots in fields
as insects will breed in ponded areas. Incorporation into
the soil during or soon after application will prevent
insect problems.
Weeds
Most weed seeds will not survive the sludge digestion process.
Tomatoes and melons are the most common exception and will
sprout in sludge applied to fields. These plants can easily
be controlled by herbicides or cultivation and generally are
not considered a problem by farmers. Plants normally con-
sidered to be noxious weeds by farmers do not enter the
6-27
-------
sludge with the sewage because they are not part of the
waste normally put into sewers. Sludge which is stored in
open lagoons will collect weed seeds just as farmland does
by natural processes. These weed seeds should be minimized
by controlling weed growth around lagoons.
Farmers who have used MMSD sludge report that they need to
apply more herbicide than normal to sludged land. This is
because the sludge additions add organic matter to the soil
which buffers the effect of herbicides and, consequently,
more herbicide must be applied. Also, the lagoon sludge
contains many weed seeds. Some farmers report that 10-
20 percent more herbicide is required.
Public Health Aspects
Sludge reuse on agricultural land must be done with caution
because digestion does not remove all pathogens. Research
on Nine Springs Sewage Treatment Works digested sludge
(Oliver 1975) showed viruses to be present. Bacteria,
protozoans, and intestinal worms are also found in processed
sludges (Surge 1974). Anaerobic digestion, which is presently
used at Nine Springs, has been shown to be very effective in
reducing pathogens (MSDG Chicago 1974; Malina et al. 1974;
Ewing and Dick 1970; and Dean and Smith 1973). Prolonged
storage of sludge, such as the lagoon solids have received,
has also been shown to be an effective method for pathogen
reduction (MSDG Chicago 1974). Pathogens which are applied
with sludge to land are readily removed by soil through the
mechanics of filtration and sorption-inactivation and by die
off. Pathogens usually do not move more than a few feet in
soil unless the soil is very coarse textured or contains
cracks or channels.
The question still to be answered by research is not whether
or not there are pathogens in sludge, but rather, what
levels are required to constitute a health haazard. There
have been no cases reported of a health hazard being traced
to digested sewage sludge (Ewing and Dick 1970). Sludge can
be disinfected by pasteurization, composting, heat drying,
and lime treatment. These procedures are all expensive, but
if required as a means to protect public health, should be
investigated and utilized. The following list of criteria,
if adhered to, should prevent any health hazard:
• Sludge must be stabilized by anaerobic digestion
or equivalent before being applied to agricultural
land.
6-28
-------
• The depth of soil between zone of sludge appli-
cation and bedrock should be at least 2 feet and
preferably 4 feet.
• Sludge should not be applied to soil in the year
the area is used for any root crops or other
vegetables which are cooked or processed. Sludge-
treated land should not be used for human food
crops to be eaten raw until 3 years after sludge
application.
• If sludge Is surface applied to sloping land,
runoff to streams or lakes should be prevented by
use of contour strips, terraces, or border areas.
• Pasture land and harvested forage should not be
used for milk cow feeding for 2 months following
sludge application. Other animals should not
graze pasture land or be fed greenchop material
for at least 2 weeks after sludge application.
• Public access must be limited in areas of sludge
application.
Heavy metals in the food chain are another potential public
health problem that must be controlled. Cadmium, in parti-
cular, is mobile in the soil and not excluded by plants.
Therefore, it can enter the food chain. Cadmium can accum-
ulate in the human body and has deleterious effects on the
kidneys and liver (Page and Bingham 1973). Public health
problems can be prevented by limiting the cadmium application
rate and monitoring crop tissue for cadmium content.
In this reuse program the cadmium application rate will be
limited to 2 pounds per acre per year and 20 pounds per acre
total over the life of the site. These limits are as recom-
mended in the DNR guidelines and are based upon research at
the University of Wisconsin (Kenneyetal. 1975). Also,
crop tissue will be monitored to detect increases in cadmium
and other trace elements.
Sludge Drying Considerations
Drying the digested sludge was studied but found unfeasible
as a means to reduce the volume of sludge to be handled.
Mechanical drying, as the Weston report discussed, is not
feasible because of the poor dewatering characteristics of
the Nine Springs Treatment Works sludge.
6-29
-------
sludge with the sewage because they are not part of the
waste normally put into sewers. Sludge which is stored in
open lagoons will collect weed seeds just as farmland does
by natural processes. These weed seeds should be minimized
by controlling weed growth around lagoons.
Farmers who have used MMSD sludge report that they need to
apply more herbicide than normal to sludged land. This is
because the sludge additions add organic matter to the soil
which buffers the effect of herbicides and, consequently,
more herbicide must be applied. Also, the lagoon sludge
contains many weed seeds. Some farmers report that 10-
20 percent more herbicide is required.
Public Health Aspects
Sludge reuse on agricultural land must be done with caution
because digestion does not remove all pathogens. Research
on Nine Springs Sewage Treatment Works digested sludge
(Cliver 1975) showed viruses to be present. Bacteria,
protozoans, and intestinal worms are also found in processed
sludges (Burge 1974). Anaerobic digestion, which is presently
used at Nine Springs, has been shown to be very effective in
reducing pathogens (MSDC Chicago 1974; Malina et al. 1974;
Ewing and Dick 1970; and Dean and Smith 1973). Prolonged
storage of sludge, such as the lagoon solids have received,
has also been shown to be an effective method for pathogen
reduction (MSDC Chicago 1974). Pathogens which are applied
with sludge to land are readily removed by soil through the
mechanics of filtration and sorption-inactivation and by die
off. Pathogens usually do not move more than a few feet in
soil unless the soil is very coarse textured or contains
cracks or channels.
The question still to be answered by research is not whether
or not there are pathogens in sludge, but rather, what
levels are required to constitute a health haazard. There
have been no cases reported of a health hazard being traced
to digested sewage sludge (Ewing and Dick 1970). Sludge can
be disinfected by pasteurization, composting, heat drying,
and lime treatment. These procedures are all expensive, but
if required as a means to protect public health, should be
investigated and utilized. The following list of criteria,
if adhered to, should prevent any health hazard:
• Sludge must be stabilized by anaerobic digestion
or equivalent before being applied to agricultural
land.
6-28
-------
• The depth of soil between zone of sludge appli-
cation and bedrock should be at least 2 feet and
preferably 4 feet.
• Sludge should not be applied to soil in the year
the area is used for any root crops or other
vegetables which are cooked or processed. Sludge-
treated land should not be used for human food
crops to be eaten raw until 3 years after sludge
application.
• If sludge is surface applied to sloping land,
runoff to streams or lakes should be prevented by
use of contour strips, terraces, or border areas.
• Pasture land and harvested forage should not be
used for milk cow feeding for 2 months following
sludge application. Other animals should not
graze pasture land or be fed greenchop material
for at least 2 weeks after sludge application.
• Public access must be limited in areas of sludge
application.
Heavy metals in the food chain are another potential public
health problem that must be controlled. Cadmium, in parti-
cular, is mobile in the soil and not excluded by plants.
Therefore, it can enter the food chain. Cadmium can accum-
ulate in the human body and has deleterious effects on the
kidneys and liver (Page and Bingham 1973). Public health
problems can be prevented by limiting the cadmium application
rate and monitoring crop tissue for cadmium content.
In this reuse program the cadmium application rate will be
limited to 2 pounds per acre per year and 20 pounds per acre
total over the life of the site. These limits are as recom-
mended in the DNR guidelines and are based upon research at
the University of Wisconsin (Kenneyetal. 1975). Also,
crop tissue will be monitored to detect increases in cadmium
and other trace elements.
Sludge Drying Considerations
Drying the digested sludge was studied but found unfeasible
as a means to reduce the volume of sludge to be handled.
Mechanical drying, as the Weston report discussed, is not
feasible because of the poor dewatering characteristics of
the Nine Springs Treatment Works sludge.
6-29
-------
Nebiker (1967) has performed research on open air drying of
sludge. He notes that the rate of drying would initially be
approximately equal to the evaporation from a free water
surface. After a certain solids content is reached, the
free water surface in the sludge will be lost, and drying
will slow greatly.
On an annual basis, the evaporation exceeds the precipitation
by only about 5 inches. During May through October, the net
evaporation is about 15 inches. Application to drying beds
on a year-round basis would not be feasible due to the small
amount of drying which could be achieved. About 100 acres
of drying bed area and 6 months sludge storage capacity
would be required. Due to the extensive facilities required
and the fact that one heavy rainstorm late in the summer
could rewet all the sludge, air drying is considered infeas-
ible.
Nitrogen Losses During Application
Research reported by Ryan and Keeney (1975) indicates that
when wastewater sludge is surface applied, between 11-60 per-
cent of the applied ammonia nitrogen can be lost by volatili-
zation. The amount lost depends on the type of soi I, the
rate of application, and the length of time before the
sludge is incorporated into the soil. When surface applica-
tion methods are used, the sludge application rate should be
adjusted upward to account for ammonia losses. The WDNR
guidelines suggest using an average 50 percent ammonia loss.
6.5 SLUDGE APPLICATION SITE INVESTIGATION
The study area was investigated to determine how much farm-
land is suitable for sludge reuse and where it is located.
This was then compared to the amount of land required to
determine the potential for success of a sludge reuse program.
Land Requirement for Sludge Reuse
The amount of land required was estimated based upon an
average sludge application of 3 tons dry solids per acre per
year. In the first year of the reuse program, it is expected
that only the amount of sludge produced by the treatment
plant, about 5,800 tons, could be used on farmland. The
lagoon weed mat removal program, other startup problems, and
arranging for farmers to use sludge is expected to prevent
large-scale use of sludge in the first year. The land
requirement for the first year will therefore be about 1,930
acres. In succeeding years much more land will be required
6-30
-------
to accept an estimated 10,000 tons of lagoon sludge each
year, plus the annual treatment plant production. The land
requirement is expected to be between 5,200 and 5,700 acres
until the lagoon is emptied. After the lagoon is emptied,
about 1986, only the treatment plant sludge will need dis-
posing. The land requirement is then expected to be from
2,400 to 3,000 acres each year.
If the same farmland is used every year, the amount of
sludge applied would not exceed about 72 tons of sludge by
the year 2000. This is well below total application limits
for the Class 1 and 2 soils. It is most likely that many
different parcels of land will have sludge applied rather
than the same land every year.
Site Suitability Criteria
Previous sections of this report have explained many of the
requirements for safe agricultural reuse of sludge. Those
requirements and several others relating to site suitability
are listed below:
• Sludge should not be applied within 1,000 feet of
public water supply wells or within 200 feet from
private water supply wells.
• Sludge should not be applied anywhere that it
could be carried by runoff to surface waters. A
buffer strip of at least 300 feet is recommended
unless it can be shown by site inspection that a
specific site has characteristics which would
allow a lower limit (between 300 and 100 feet)
without runoff or contamination problems.
• Sludge should not be used where it would endanger
rare and endangered plants or animals.
• Sludge application should be limited to sites
which are actively farmed.
• Sludge application sites should be at least 500
feet from concentrated population areas, urban and
suburban housing tracts, rural subdivisions,
commercial areas, recreation spots, or schools if
the sludge is surface-applied. If it is subsur-
face injected, the buffer shall be a minimum of
300 feet.
6-31
-------
• Sludge may not be applied within 300 feet of rural
homes and gardens unless the District first contacts
affected residents, explains the program, and
obtains their permission to apply sludge closer.
The minimum buffer distance may be 200 feet if the
sludge is surface applied or 100 feet if subsurface
injected. Sludge must not be applied where it
could be carried by runoff onto the farmstead.
• Sludge lagoons, sprinkler application systems, and
other unsightly facilities or operations shall be
located so as to be screened from major public
view.
• Sites subject to occasional or frequent flooding,
more than once in 20 years, are not suitable for
sludge application. Areas subject to rare flooding,
less than once in 20 years, will have the require-
ment that sludge be applied and mixed into the
soil at least 2 months before any potential flood
season.
• Sludge application sites must have depth to season-
ally high ground-water table of at least 3 feet
and preferably 5 feet.
• Sludge application sites must have depth to bedrock
or other impermeable layer of at least 3.5 feet
and preferably 5 feet. Areas with bedrock less
than 5 feet shall be used only if better sites are
not available.
• Sites with both bedrock and ground-water depths
less than 5 feet are not suitable for sludge
application.
• Sites with slopes greater than 12 percent are not
suitable for sludge application unless special
measures are taken to prevent erosion.
• All District-owned sites and facilities should be
located within Dane County.
Land Available for Sludge Reuse
Soil suitability and land use are the two major factors of
land availability for sludge reuse. These two factors were
mapped to determine their extent.
6-32
-------
Soils. The soils in the study area were mapped by sludge
application suitability class on the detailed soils maps of
Dane County. The detailed maps were used as the basis of
determining amounts and locations of suitable soils. Due to
the size and detail of the detailed soils maps, they could
not be incorporated into this report. Therefore, a more
general soil suitability map was prepared. This general map
of soil suitability for sludge application appears on Fig-
ure 6-4. The general soils map groups are comprised of the
following soil classes. General Soil Croup A is about 75
percent Class 1 and up to 25 percent Classes 2,3, and 4.
General Soil Group B is about 75 percent Classes 2 and 3
with up to 25 percent of Classes 1 and 4. General Soil
Group C is about 75 percent Class 4 soils and up to 25
percent of Classes 1,2, and 3. The general soil map is
meant for illustrative purposes only. The detailed soil
survey maps must be used when looking at individual farms.
Land Use. Areas of land unsuited for sludge reuse including
cities, population centers, recreational areas, schools,
subdivisions, commercial, and industrial areas, are shown on
Figure 6-5. These areas must be avoided for sludge reuse as
much as possible. Figure 6-5 also indicates the locations
and densities of rural homes. Areas with many clustered
homes should also be avoided.
The soils and land use maps were overlain together to deter-
mine the amount of land suitable for sludge reuse. About
40,000 acres, or 44 percent of the 91,000 acres of cropland,
in the study area can be used for sludge reuse. In comparing
this to the highest expected land requirement of less than
6,000 acres, it is apparent that more than enough land is
available in the study area.
6.6 SUMMARY
This chapter has discussed the many factors related to
agricultural reuse of sludge. A study area consisting of
the land within a 10-mile radius of the Nine Springs Sewage
Treatment Works was delineated as a basis for discussion.
The study area contains about 91,000 acres of very produc-
tive farmland. Its soils, land use, and ground-water condi-
tions were investigated for their suitability for sludge
reuse. Based upon the site investigations, it was determined
that about 44 percent of the study area, or 40,000 acres, is
suitable for sludge application. Farmers representing more
than 5,000 acres of farmland have already shown a strong
interest in having sludge applied to their land. The amount
of farmland available for sludge reuse is expected to increase
rapidly after the reuse program is started.
6-33
-------
SCALE IN MILES
LEGEND
MOST OF SOILS
SUITABLE FOR
SLUDGE APPLICATION
SOME SOILS
SUITABLE FOR
SLUDGE APPLICATION
FEW OF THE SOILS
SUITABLE FOR
APPLICATION
FIGURE 6-4
GENERAL SOIL MAP
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
S9166.0
-------
0 2
1 1
SCALE IN MILES
LEGEND
AREAS CF LAND USE
UNSUITABLE FOR
SLUDGE RE1 'SF
o RURAL HOMESITES
FIGURE 6-5
LAND USE
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
^89166.0
4
H
CH2M
BHILL
-------
The amount of land required for reuse of all the Nine Springs
Sewage Treatment Works sludge will be between 5,200 and
5,700 acres until the lagoons are emptied. Thereafter, only
about 2,400 to 3,000 acres will be needed each year. The
land area requirement is based upon recommended annual and
total sludge application rates which were developed in this
chapter. The sludge application rates were set to guard
agamst potentially harmful overapplication of crop nutrients
and heavy metals.
This chapter also included criteria for determining the
suitability of particular sites for sludge application and
site management necessary to protect the surrounding
environment.
6-36
-------
7.1 CRITERIA FOR PROGRAM SELECTION
7,2 ACCEPTABLE SLUDGE REUSE PROGRAMS
73 SLUDGE HANDLING CONTINGENCY PLAN
7.4 PRESENT METHOD OF SLUDGE REUSE
7.5 FUTURE SLUDGE HANDLING FACILITIES CONSIDERED
7.6 COMPARISON OF SLUDGE REUSE PROGRAMS
SLUDGE REUSE PROGRAMS
7
-------
Chapter 7
SLUDGE REUSE PROGRAMS
An organized program will be required to ensure successful
and safe sludge reuse. The program must outline procedures
for management and for distribution and land application of
sludge. Management considerations include the application
rate categories of fertilizer rate, high-rate fertilizer,
and disposal. For distribution and application, the reuse
program considerations include District-owned land, land
leased by District, and farmer-owned and controlled land.
7.1 CRITERIA FOR PROGRAM SELECTION
Program Criteria
To choose between the many possible alternative systems for
recycling sludge, it is necessary to first determine criteria
which the reuse program must meet. The criteria are as
follows:
• The program must be able to handle all of the
annual treatment plant sludge production plus the
sludge to be removed from the lagoons.
• The program must recycle the sludge back into
agriculture.
• The program must be flexible.
• The program must be acceptable to the farm com-
munity.
• There must be no pollution of ground or surface
waters.
• There must be minimum detriment to other environ-
mental factors.
• The program must be cost effective.
7-1
-------
Reuse Programs Eliminated
Use of the above criteria and the findings of previous
chapters eliminate the following alternatives from further
consideration:
1. MMSD ownership and operation of a site for recycle of
all the treatment plant and lagoon sludge.
2. High-rate fertilizer and disposal methods of sludge
application to land.
The first system would require MMSD purchase and management
of several thousand acres of the better farmland in Dane
County. Purchase of a large tract of land for this purpose
would be very expensive and politically difficult if not
impossible. As discussed in Chapter 6, MMSD takeover of
land and the relocation of many farming and rural families
would certainly not be acceptable to the farm community.
The high-rate fertilizer and disposal methods of land appli-
cation would result in environmental degradation and wasting
of valuable nutrients. As was indicated in Chapter 3, the
high-rate fertilizer and disposal methods apply more nutri-
ents than crops can use. Consequently, excess nitrate would
be leached below the root zone and eventually into ground-
water and surface water supplies. These methods would also
overload the soil with salts and heavy metals which would
reduce or prevent crop production and become a health hazard
in the food chain. These methods would also result in the
valuable nutrients in the sludge being wasted, rather than
being recycled into agricultural production.
7.2 ACCEPTABLE SLUDGE REUSE PROGRAMS
Several alternative reuse programs were developed and then
compared to select a cost effective, reliable, and farm-
community-supported sludge reuse program. They are similar
to the HYDIC and BIOGRO programs in which digested liquid
sludge is made available for fertilizer rate agricultural
reuse by farmers who request it. Two requirements common to
reuse programs of this type are (1) the District must develop
a market for the sludge, and (2) a contingency plan must be
available in case the market for sludge is lost. The reuse
programs developed for further study and comparison are as
follows:
7-2
-------
• Reuse Program 1—Market ail sludge to farmers.
* Reuse Program 2—Lease land for short periods for
sludge application.
* Reuse Program 3—Combination marketing and land
leasing.
Reuse Program 1—Market All Sludge
Description. The District would make sludge available to
area farmers as they request it for fertilizer rate applica-
tion to their farmland. A public relations program would be
developed to aid in marketing the sludge. The farmer would
have complete control over his land. He would contact MMSD
when he wanted sludge, then he and a District representative
would determine the suitable time, location, and application
rates for sludge application.
Facilities Requirements. In this program, sludge demand is
expected to be high during April and May and again in Septem-
ber through November, whereas the supply of sludge is uniform
each month. Therefore, facilities for sludge storage and
high seasonal sludge distribution and application will be
required.
The storage requirement for Program 1 was calculated based
upon the monthly use shown in Table 6-7 and upon the esti-
mated uniform sludge production each month. The calculated
storage capacity required is 33.4 percent of annual treatment
plant production. The recommended design storage capacity
is 75 percent of annual production (150 acre-feet) to allow
5 months extra capacity in case adverse weather delays or
prevents spring sludge use. The sludge would be stored in
Nine Springs Lagoon 1, in small on-farm lagoons,, or at
distribution centers. Lagoon 2 will be abandoned as recom-
mended in Chapter 5. The storage facilities would be filled
during the winter months of no sludge use and the midsummer
months of expected low sludge use. All storage should be
emptied by about November each year.
In addition to providing some seasonal sludge storage, on-
farm lagoons would relieve some of the peak season distribu-
tion requirements. The District would need to obtain a
commitment from the farmer to accept sludge for several
years before helping to build a small lagoon. A 3-5 acre-
foot-capacity lagoon would be required to hold enough sludge
for application to 100 acres.
7-3
-------
The sludge handling facilities should be sized to distribute
and apply, in 1 month, 35 percent of the amount of sludge
used in the year. This is based upon Table 6-7 which indi-
cates that the peak month use will be about 30 percent of
annual use. An extra 5 percent was added for contingency.
If the distribution and application system fails to meet
demand for even one season, many farmers may stop using
sludge because they may feel they cannot rely on the system
to meet their needs.
Distribution centers could be used after strong sludge reuse
market areas develop. These would serve as a central point
from which sludge would be supplied to surrounding farmers.
Sludge would be pumped via pipeline from the Nine Springs
Works as used or be stored at the distribution center until
used. The advantage of using a pipeline is that, in general,
it will be more economical to transport the sludge longer
distances by pipeline than by truck. The distribution
center could also be used for research, demonstration, and
monitoring. The storage capacity at a distribution center
would depend upon the size of the market served from it.
Strong interest has been shown for a sludge distribution
center in the Cottage Grove area. The area around Oregon
may also be suitable for a distribution point. The District
should wait until a strong market is developed in an area
before locating distribution centers. Potentially strong
market areas cannot be determined with enough reliability to
select sites at this time.
The land application sites would be located wherever a
farmer wanted sludge applied, as limited by the site selec-
tion criteria. Farms nearer to the Nine Springs plant
should be given first preference as this will reduce the
District's transportation costs.
Program Management. The District must appoint a person to
manage the sludge reuse program. Duties of this manager
would include scheduling distribution and application,
answering farmers' questions, reviewing requested sites and
application rates, directing the monitoring program, and
marketing sludge for reuse. This person should be capable
of talking to farmers in their terms, be familiar with the
local agriculture, and be enthusiastic about the project.
Marketing Program. In order for the concept of farmers
asking for sludge to become reality, the District must
develop a strong community involvement program. This has
already been started by the District staff and has been
7-4
-------
continued with the farm community meetings which were a part
of this planning study. This should be continued by the use
of educational programs sponsored by MMSD.
The public's view of the sludge reuse facilities and opera-
tion must be carefully maintained by the District. For
instance, the truck drivers should be considered as ambassa-
dors of the District because they are in everyday contact
with the farmers and rural public. Clean trucks and cour-
teous, helpful operators can be very important in achieving
a successful program.
Another marketing concept that should be used is an attrac-
tive informational brochure which would explain to the
public what sludge is, how it is beneficial to agriculture,
and how farmers can contact MMSD and arrange to get sludge
applied on their land. Also, the sludge should be given a
trade name such as HYDIC or BIOCRO. This would eliminate
the need for calling it sewage sludge, which admittedly is a
negative term. The farm community knows that it is sludge,
but they need not be continually reminded.
Monitoring Program. The District must implement a program
to monitor the effects pf sludge reuse for two reasons:
(1) it is required by State and Federal regulations and,
just as important, (2) the farmers will feel more confident
using sludge if they are assured that someone competent is
guarding their soil and crop production.
Reuse Program 2—Lease Land for Sludge Application
Description. In this program, the District would lease or
rent land from farmers for sludge application. Since sludge
would be applied during the growing season, no crops would
be grown that year. The lease cost, therefore, would have
to offset the net returns the farmer would have otherwise
received from a crop plus the fixed costs of equipment and
land ownership.
The amount of leased land and consequently the program cost
could be reduced by applying enough sludge to satisfy the
crop nutrient requirements for more than 1 year. U. S. EPA
guidelines limit available nitrogen application to twice the
crop nitrogen requirement in a single year. Only heavy,
moderate to slow permeability soils are suitable for this
program because they would not allow the excess nitrogen to
be leached below the root zone in the first year. The cost
of leasing land for this program is estimated to be $38.60
per acre or $5.68 per dry ton of sludge applied where
7-5
-------
2 years of sludge is applied in 1 year. The basis of the
land lease cost is shown in Table B-5. The lease cost would
be reviewed each year to allow for different farming costs
and crop sale values.
Two purposes for obtaining leases for the land are (1) the
District would be assured of land for sludge application for
some period in advance, and (2) sludge application could be
scheduled evenly throughout the summer, thereby reducing
peak handling requirements. The farmer would benefit from
knowing he would not be hurt by crop failure, fertilizer
would be applied onto his land, and he would not need to
farm the land for one season. Depending upon the interest
in this program, the leases could be procured by competitive
bidding or by the program manager approaching individual
landowners with the program.
Facilities Required. The facilities would be set up to
supply sludge to land according to a schedule set up by the
District. If weather permits, sludge would be applied
evenly over the 8-month period, April through November.
This results in 12.5 percent of the annual sludge reused
being applied in each month. The handling facilities should
be sized to handle an extra 5 percent to allow for contin-
gency .
The total storage capacity should be designed for 75 percent
of annual treatment plant sludge production. This is based
on the same estimates as used for Reuse Program 1. Workable
storage locations would be in the Nine Springs Lagoon 1 and
at one or more central distribution points as described for
Reuse Program 1.
In a leased land program, it is likely that the application
sites would be smaller and more widely scattered than as in
Reuse Program 1 because an actively farming landowner would
be reluctant to lease all of his land to MMSD for 1 year.
Rather, he would likely lease a small portion 1 year, a
different portion the next year, etc.
Program Management. As in Reuse Program 1, the District
should appoint a program manager. His duties would include
finding and arranging land leases in addition to scheduling
sludge handling, talking to farmers, reviewing sites and
on-farm management, directing monitoring, and marketing the
sludge.
7-6
-------
Marketing and Monitoring Programs. The District will need
to both market the sludge and monitor the reuse as in Reuse
Program 1. The success of this program depends upon making
farmers aware of the program, how it works, and showing them
the benefits. The program must be monitored to satisfy
regulatory agency requirements and, more important, to show
the farmer that MMSD cares about their crops and land.
Reuse Program 3—Combination Sludge Marketing and Land
Leasing
This program would be set up to market sludge to farmers for
use on their land as in Reuse Program 1, plus it would
include provisions for MMSD leasing land as in Program 2.
MMSD-leased land would be used to apply sludge during the
low-use months of July and August. This would spread the
application period out more evenly over the year and thus
reduce peak sludge handling requirements. The amount of
land leased versus that kept in private management would
depend upon the farm community.
The sludge storage capacity, the program management, and the
marketing and monitoring programs would be the same as
described for Reuse Programs 1 and 2. The capacity of the
sludge distribution and application facilities would be
between the estimated requirements for Reuse Programs 1 and
2.
7.3 SLUDGE HANDLING CONTINGENCY PLAN
A contingency plan must be available for sludge handling in
the event that the sludge reuse market is suddenly lost. A
marked decrease in the number of farmers requesting sludge
could be caused by a reduction in the price of commercial
fertilizer, a publicity scare, or a change in the sludge
character. If a problem does develop, the District's first
effort should be to find the cause of the problem and correct
it. In the case of lower commercial fertilizer prices, the
District must simply make sludge reuse more economically
attractive by lowering or cutting out any cost to the farmer,
or maybe even paying them to take sludge.
A continuing public relations and educational program must
be used to prevent the farmers from being frightened of
sludge reuse by unfounded claims. If the sludge character
changes, making it undesirable for agricultural reuse, the
reason for the change should be found and corrected. If,
for instance, a particularly high toxic metal concentration
occurs in the sludge, the source should be found and removed.
7-7
-------
In the event that it is not possible to prevent loss of the
sludge market, an alternative temporary sludge handling and
disposal method should be available. The sludge handling
alternative should be able to handle the sludge for about
3 years until the sludge market can be restored or until
another disposal method could be developed. Possible alter-
native temporary programs would be to (1) have several
thousand acres of District-owned or option-to-control land
available for sludge application, (2) have facilities for
incineration or dewatering and landfill available for sludge
disposal, or (3) have capacity to store sludge for 3 years.
The first and second alternatives are not feasible because
of the high cost and impracticability. The third alternative
is recommended: store the sludge until a permanent solution
can be found. The west half of the Lagoon 1 storage area
will have capacity to store 75 percent of 1 year's sludge
production at 2.3 percent solids. With concentration to
10 percent solids, as is currently achieved after a freeze-
thaw cycle, this storage area could hold 3 years' treatment
plant sludge production. Also, the dikes surrounding the
east half of Lagoon 1 should be left intact, except as
required to allow drainage, after the sludge is removed.
This area would then, with minor rehabilitation, be suitable
for storage of an additional 3 years' sludge production in
an emergency. The Mud Cat and supernatant return and treat-
ment facilities will be available to concentrate the lagoon
solids.
If loss of a sludge reuse market is to occur, it will most
likely happen in the first years of the program before
sludge reuse becomes a common, well-accepted practice.
After many years of sludge reuse, the chance of losing the
sludge market would be very remote. Sludge marketing is a
vital element of the sludge reuse program, and all should be
done, especially by way of public education, to assure the
program's success.
7.4 PRESENT METHOD OF SLUDGE REUSE
The present method of sludge reuse is a form of Reuse Pro-
gram 1. The farmers, upon hearing that MMSD had sludge to
dispose of, asked for it, and the District hauled and applied
it for them. The present program includes monitoring of
streams near sludge application sites.
7-8
-------
The present method of handling and disposing of the anaerobic-
ally digested sludge produced at the Nine Springs Treatment
Plant consists of two steps. First, the sludge is piped
from the digesters to Lagoon 1. The average rate for the
last 4 months of 1974 was 184,000 gallons per day. A drag-
line is then used to remove sludge from the lagoons. The
sludge is put into trucks which haul it to nearby farms
where it is dumped into piles. The piles are then spread by
a grader.
In 1974-6,682 tons of sludge were removed from the lagoons
and hauled to farmland or on-site stockpile. Sludge was
hauled for 29 days between 23 January and 4 March and for
another 37 days between 21 October and 31 December. Sludge
was also hauled until early February 1975 and again in the
fall. The application rates during 1974 ranged from 2.8 dry
tons to 28.2 dry tons per acre.
The District estimated that the cost of the dragline and
trucking operation in 1974 was $9.06 per dry ton. To this
we added an estimate of the cost of spreading, supervision,
and sampling and testing. This produced an estimated total
cost for sludge reuse in 1974 of about $11 per dry ton.
The District takes care while loading sludge into the trucks
so that none will spill onto roads. There are some problems,
though, with the present method of sludge disposal. It was
noted on one farm in February 1975 that large frozen pieces
of sludge lay on top of the frozen soil. When the spring
thaw came, this sludge was apparently washed down a draw
past several homes toward Lake Waubesa. This caused some
complaints from residents located between the fields and the
lake. Also, the sludge application rates used on some
fields are considerably higher than required to meet the
nitrogen requirements of the crops.
7.5 FUTURE SLUDGE HANDLING FACILITIES CONSIDERED
The sludge handling facilities, namely the transport, storage,
and application methods, and their costs must be determined
in order to select the best sludge reuse program. All
sludge handling facilities were compared using a 3.0 dry
tons per acre application of 5 percent solids sludge. This
is equivalent to a liquid application of 14,400 gallons per
acre or 0.53 acre-inch of liquid per acre.
7-9
-------
Transport Facilities
The two most feasible methods of transporting the liquid
sludge are by pipeline and tanker truck. Rail transpor-
tation may be feasible in some instances, but was not
studied in detail here.
LAGOON CLEAN-OUT OPERATION AND TRUCK-
LOADING FACILITY
The source of sludge at the Nine Springs Works will be a
transfer-loading-pumping facility to which both the lagoon
and digester sludge will be pumped or drained to. The
digester sludge will normally be routed through the lagoon
for storage, and because lagoon aging and/or dewatering may
be desirable or necessary before land application of the
sludge.
Truck Transport. Trucks with closed tanks would be used to
prevent sludge spillage. They would be filled by either
pumping directly into the tank or by first pumping to a
loading dock and then discharging into the truck tank. The
trucks could be filled at the Nine Springs site or at a
7-10
-------
remote loading dock fed by a pipeline. The tanker trucks
would transport the liquid sludge to fields or temporary
storage facilities for eventual land application by other
equipment. Special on-off road trucks which can transport
and apply sludge have also been developed; in this report
they are considered in the sludge application methods discus-
sions.
Many of the county and town roads in the study area are
posted with reduced load limits in spring because of soft
conditions resulting from thawing of the ground. This
occurs mostly in March through May and has to be considered
in studying truck transport of sludge. The trucks should be
equipped with aluminum tanks and any other cost effective
weight reducing designs. The tank capacity should be limited
to 5,000 gallons maximum. If the trucks are kept on Class A
county roads or better, 6,000-gallon tanks could be used.
The cost for 5-mile transport with a 5,000-gallon tanker
truck is estimated to be $2.69 per dry ton-mile. One truck
could haul about 50,000 gallons per 8-hour day. See
Table B-6 for the cost and capacity development. The cost
of a loading dock capable of holding three truckloads of
liquid sludge is about $50,000.
Pipeline Transport. A 5-mile transportation distance was
also used in considering a pipeline to make the costs
comparable to truck transportation. The pipeline transport
cost development is given in Table B-7 and is for a
500-gallon-per-minute capacity system. The cost is estimated
to be $1.57 per dry ton-mile. This system would include a
pump station and buried pipeline. The cost could change,
depending upon the designed capacity, pipeline route, and
discharge point elevation. A higher-capacity system will
generally have a lower per ton-mile cost, whereas a lower
capacity system will normally be more costly. The 500-gpm
system capacity used here is about four times as great as
the average sewage treatment plant output. This excess
capacity will be required during peak sludge use periods and
to handle the lagoon sludge.
Pipeline transportation has the advantage of being more cost
effective than truck transportation. Also, if possible, it
should be routed to serve some farmers along its length. A
major disadvantage of a pipeline is that it can serve only
areas which it passes over or borders on, and its use at all
depends upon the market area served by it. The end point
and location of the pipeline cannot be determined until a
reliable market for sludge large enough to make a pipeline
cost effective is developed.
7-11
-------
Sludge Storage Facilities
Intermediate sludge storage facilities may be useful between
the transportation and application systems to increase the
efficiency of those systems. For instance, small on-farm
storage ponds, which would be filled by tanker truck during
the offseason, could supply sludge for land application
when needed. This would reduce the peak period sludge
transportation requirement. Another intermediate sludge
handling system would be to use portable nurse tanks in
fields to provide a continuous supply of sludge to the
application equipment. The nurse tanks would be intermit-
tently filled by tanker trucks.
Storage of the treatment plant sludge will be provided in
Lagoon 1 as recommended in Chapter 5 of this report.
On-Farm Storage Lagoons. A lagoon with about 4.5 acre-feet
of storage capacity would be required to hold enough 5 per-
cent solids sludge for application to 100 acres. This is
about the size that would be required by most farmers. On
large farms with several hundred acres, several lagoons
would be placed in different locations to serve separate
fields.
The on-farm lagoons should be located away from shallow
ground water and bedrock, out of frequent public view, where
they could be reached by tanker truck or pipeline source,
and where they could effectively serve the fields. A quali-
fied District representative would perform the necessary
site investigations and select a lagoon site that would
conform to District requirements and be acceptable to the
landowner and WDNR. Figure 7-1 shows the design consider-
ations for an on-farm lagoon. The lagoons must be designed
to ensure that they would not leak and have stable dikes.
The lagoons should be built by the District to assure proper
construction. Concrete ramps and other necessary appurte-
nances would be provided so that the lagoons can be maintained
The sludge solids will probably settle out in the lagoons
after some time as experience has shown in the Nine Springs
Lagoons. Therefore, the sludge may require slurry ing before
removal for application to land. The District should supply
a portable slurrying pump, as commonly available for manure
pits, to slurry the lagooned sludge. One such pump can
slurry the sludge in a pond within 1 day's time and therefore
be able to handle all of the small on-farm lagoons. District
ownership of the slurry pump and the pumps to remove sludge
7-12
-------
190'
CONCRETE
RAMP.
1
10' TOP
WIDTH (TYP )
I
'f
V
GATE
, 2' FREEBOARD
CLAY LINER MAY
BE REQUIRED ON
SANDY SOILS
FENCE
(ALL AROUND)
. S9166.0
FIGURE 7-1
ON-FARM
LAGOON DESIGN CONSIDERATIONS
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
from the lagoons would assure District involvement in the
application of the sludge.
The District would need to obtain a commitment from a farmer
to accept sludge for many years before constructing a lagoon
or any permanent facility on the farmer's land. The ques-
tion as to whether farmers would accept such an arrangement
was asked by questionnaire at the 2 October 1975 meeting
with the farm community. Four out of six respondents to the
question said they would. The other farmers at the meeting
showed positive interest in such an arrangement but did not
state so on a questionnaire. After the farmers have used
sludge for a few years, it is expected that many more will
want permanent facilities on their land. They would benefit
from permanent facilities by being assured of sludge on a
priority basis and possibly at less cost than other farmers.
As shown in Table B-8, the cost of a small 4. 5-acre-foot
capacity on-farm lagoon has been estimated to be $8,500 for
average site conditions.
Nurse Tank. A nurse tank could be used to provide a contin-
uous supply of sludge to application equipment where a
pipeline or lagoon source is not located close by. This
nurse tank could be the trailer from a tractor-trailer
tanker truck or a very large capacity tank on wheels. The
very large nurse tank could have a capacity of over
15,000 gallons when filled and would be towed to the field
empty. It would be filled by tanker truck, whereas an empty
trailer tank would be exchanged for a full trailer when
empty. The estimated cost of either type of nurse tank
would be about $15,000.
Sludge Application Methods
Four methods of liquid sludge application were investigated:
sprinkler application, soil injection, truck spreading, and
tractor spreading. These were studied to determine their
cost, ground coverage rate, effects on the fields, and
farmer and public acceptance.
Sprinkler Application. Big gun sprinklers are required
rather than the smaller sprinkler systems in order to spray
the large sized particles in sludge. Big gun sprinkler
systems have been used successfully for sludge application.
The system would consist of a source which could provide a
continuous supply of sludge such as an on-farm lagoon, nurse
tank, or main sludge pipeline. An on-farm lagoon or nurse
7-14
-------
HAND MOVEABLE BIG GUN SPRINKLER
PORTABLE SLUDGE PUMP
7-15
-------
DEEP-SIX INJECTOR
Flexible hose supply systems, which were originally per-
fected for traveling big gun sprinklers, have been adapted
to provide a continuous supply to sludge application sys-
tems. A soil injection system works very efficiently with
this type of supply line. Up to 15 acres can be covered
with a single hookup with a typical 660-foot-long flexible
hose as shown on Figure 7-2. The sludge source could again
be an on-farm lagoon, nurse tank, or pipeline. A pump would
be required if a lagoon or nurse tank source is used. Hand-
movable irrigation pipe or a permanent buried pipeline could
be used to carry sludge from the source to the flexible hose
feed line. A method to anchor the pipeline where the flex-
ible hose is attached would be required with movable pipe.
Injectors till the soil and therefore need a tractor with
considerable power to pull them. A 40-hp crawler tractor or
60-hp wheel tractor will generally be required to pull a
five- or seven-sweep injector. It is assumed that the
District would need to provide the tractor and injector for
the farmer to use. The equipment could be transported to
the field on a1 loboy trailer. The farmer could operate the
soil injection application equipment after some instruction.
Many farmers would not allow someone unfamiliar with farming
to operate this type of equipment on their land.
7-17
-------
tank would require a portable pump. The pipeline from the
source to the sprinkler could be either hand-move irrigation
pipe or a permanent buried lateral.
A major advantage of the sprinkler method over other appli-
cation methods is that the system could be used on growing
grain crops and while the soil is too soft for heavy equip-
ment. A hand-movable sprinkler was used for this analysis,
but a self-propelled big gun system could also be used.
Other advantages of a big gun sprinkler system are that it
will cause little or no soil compaction, it is suitable on
soft soils, and continuous feed is possible. Continuous
feed allows much more efficient operation of the application
equipment than a system where the equipment must travel
across the field to fill up, then return to where it was
working for a short period until it empties again.
Two major disadvantages of this system are its adverse
visual impact and soil sealing effect. This system could
not be used close to roads or homes where easi ly seen by the
public. The sight of black sludge being sprayed several
hundred feet across a field is certain to cause complaints.
These complaints would be for imagined or real odors and/or
wind-carried aerosols. Also, when sludge is sprayed onto
soil, it will form a thin crust or seal when it dries. This
seal is a problem in that it slows soil drying and could
cause excessive rainfall runoff and washoff of sludge in a
rainstorm. The sludge film should be broken up by soil
incorporation or harrowing as soon as possible after applica-
tion.
A big gun sprinkler application system, as shown in
Table B-9, could cover about 6.0 acres per 8-hour day. The
cost is estimated to be about $3.56 per ton dry solids. The
farmer could provide the labor to operate the system.
Soil Injection. Many types of soil or subsurface injection
systems have been developed and used. A commercially avail-
able system developed at Colorado State University was used
in this discussion because it is designed to mix the sludge
with the soil better and has a faster application rate than
most other systems.
7-16
-------
750'
SOURCE:
PIPELINE
LAGOON, OR
NURSE TANK
PERMANENT OR HAND
MOVEABLE PIPELINE
S9166.0
FIGURE 7-2
FLEXIBLE HOSE SLUDGE SUPPLY SYSTEM
WITH SUBSURFACE INJECTOR
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
ON-FARM LAGOON, SPRINKLER APPLICATION,
AND SOIL INJECTION
Soil injection is the best application method in terms of
effects on the environment and the public. The sludge is
placed beneath the soil surface and would not be visible to
the public. Subsoil placement also prevents the loss of any
nutrients and washing of the sludge from the surface. It
will be permissible to use soil injection closer to housing
and other such developed areas than would be allowed with
other sludge application methods. Subsurface injection
cannot be used on cropped land because the injector sweeps
would cut the crop roots and tear out plants.
A subsurface injection system can cover about 9 acres in an
8-hour day. The cost would be about $5.93 per ton solids.
The land coverage rate and costs are developed in Table B-10.
Truck Spreader. This system would consist of a truck capable
of hauling a 1,500- to 2,500-gallon tank of liquid sludge in
the fields. The sludge is spread across a 10- to 30-foot-
wide strip behind the truck by pumping at low pressure
7-19
-------
against a deflector plate or through a large nozzle. Two or
three passes may be required to apply one-half inch of
liquid sludge without causing it to run off and pond. The
truck can empty itself in a matter of a few minutes, which
requires that it spend a great deal of time traveling back
and forth across the field to be filled. Some commercially
available units are also capable of traveling on the highway
to transport the sludge. A 1,600-gallon capacity Big Wheels
brand liquid sludge spreader truck as demonstrated at the
Nine Springs Works on 30 May 1975 was used as the basis of
the costs and capacity development.
BIG WHEELS SLUDGE SPREADER TRUCK
The major advantage of truck spreading is that it is not
restricted to any field or portion of a field. This flexi-
bility would allow a single truck to quickly serve any
portion of a farmer's land or several different fields in a
single day. The truck spreader would require special
operating skills and therefore should be operated by MMSD
personnel.
Truck spreading has several disadvantages related to its
effects on soils. Special high flotation tires are required
to minimize soil compaction. Even with these special tires,
the truck cannot be used on wet, soft soils or on steep
7-20
-------
hillsides. The tires, being quite wide, would do much
damage to crops such as corn or grain. The trucks would
most suitable for sludge application in the fall after crop
harvest while the soil is dry.
be
TRUCK SPREADERS AND TANKER TRAILERS
A single truck which would be filled from tankers at the
edge of the field could cover about 4.2 acres per 8-hour
day. The estimated cost of truck spreading in this case
would be about $11.90 per ton solids. The development of
the costs and capacity are shown in Table B-11.
Tractor Spreading. This is a term we have applied to a new
concept in liquid sludge application. It consists of a
tractor which carries or pulls a liquid sludge spreader on a
small trailer. This spreader device consists of an appara-
tus for connecting a flexible feed hose to it, a valve
controlled from the tractor, and a spreader deflector plate
or nozzle for spreading the sludge. The spreader would be
fed by dragging a flexible hose as described for the soil
injection system and shown on Figure 7-2. It spreads sludge
7-21
-------
TRACTOR SPREADER AND NURSE TANK SUPPLY
in a 10- to 30-foot-wide path behind the tractor. This
system has the advantage of being continuously fed by a
flexible hose plus it applies sludge with a relatively
inexpensive uncomplicated piece of equipment. A schematic
diagram of the spreader device is shown on Figure 7-3.
The tractor could be owned and operated by the farmer and
could have low power. The only requirement would be that a
cab be provided to protect the operator from the sludge
spray. Many farmers already have cabs installed on their
tractors. The pump, hose, and spreader device would be
supplied by the District.
This system has the disadvantage of crop damage by the
effect of the hose being dragged across the field, pro-
hibiting its use on crops such as grain or corn. It would
be best suited for fallow or harvested land, although it
could be used on recently mowed or grazed forage crops.
-------
DEFLECTOR PLATE
CONNECTOR
FLEXIBLE
HOSE
.59166.0
FIGURE 7-3
SCHEMATIC DIAGRAM OF
TRACTOR SPREADER DEVICE
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
-------
Of the four sludge application methods discussed, tractor
spreading has the fastest ground coverage rate, about
15 acres per day. This high efficiency and the relatively
minor equipment specialization account for the low cost,
estimated to be about $2.44 per ton solids. The basis for
the costs and system capacity is given in Table B-12.
Other Sludge Application Methods, Many other sludge appli-
cation methods are available and have been used success-
fully. No attempt was made to determine the cost of or
investigate all variations in detail since the four described
methods cover the major basic types. Some variations from
the described methods could be used in order to meet the
special needs of MMSD and the local farmers.
One different type of feed system which should be discussed
is the use of a tank trailer pulled by a tractor which would
supply sludge to either a soil injector or spreader. Many
dairy farmers will already own equipment of this type for
manure handling. A trailer tank would have the same dis-
advantage of a truck spreader: the necessity of traveling
back to the source to fill. This method would be most
suitable where the farmer already has the equipment, where a
long time period for application to the field is available,
and on small fields.
Comparison of Sludge Application Methods
The four described sludge application methods are compared
in Table 7-1. The big gun sprinkler system is least suit-
able because of its adverse environmental problems of great
visual impact and odor potential. The restrictions which
would be required for separating distance between the
sprinkler system and houses, roads, water courses, etc.,
also make this method generally unfeasible. The remaining
methods are all acceptable, but each have their own major
advantage. Subsoil injection's advantage is that it places
the sludge out of sight of the sensitive public. Truck
spreading is most mobile and flexible. Tractor spreading is
the most efficient and most economical method.
7-24
-------
TABLE 7-1
COMPARISON OF SLUDGE APPLICATION METHODS
MADISON METROPOLITAN SEWERAGE DISTRICT
SLUDGE APPLICATION METHOD
FACTORS OF
COMPARISON
Soil Compaction
Suitability on Wet on Soft SQI!
Suitability on Slopes
Soil Sealing Potential
Suitability on Crops
Corn and Grain
Harvested Forage
Field Efficiency"
Tied to Source Location
Feed Methods
Visual Impact
Odor Potential
Nitrogen Loss
Labor Required
Land Coverage Rate
Cost"
BIG GUN
SPRINKLER
None
Suitable
Suitable
Moderate
Suitable
Suitable
Medium (56%)
Yes
Continuous
Yes
Yes
Highest
Medium 10.08 man-day/Ac)
Low (6 Ac/day)
Low l$3.56/tpn)
SOIL
INJECTION
None
Moderately Suitable
Suitable
None
Not Suitable
Not Suitable
High (80%]
Yes
Continuous Possible
None
None
None
High (0.11 man-day/Ac)
Medium (9 Ac/day)
Medium l$593/ton)
TRUCK
SPREADING
Minor in Fall
High in Spring
Not Suitable
Least Suitable
Moderate
Not Suitable
Suitable
Very Low (18%)
No
Intermittent
Moderate
Moderate
Moderate
Very High (0.24 man-di
Low (4 Ac/day)
High(S11 90/ton)
TRACTOR
SPREADING
Minor
Moderately Suitable
Suitable
Moderate
Not Suitable
Suitable
Medium (64%)
Yes
Continuous Required
Moderate
Moderate
Moderate
>y/Ac) Low (007 man-day/Ac)
High (15 Ac/day)
Low l$2.44/ton)
'Field efficiency is the time actually spent applying sludge
divided by the time in the wprkday.
"Cost per ton for 5% solids content liqytd sludge applied at
rate of 14,400 gat Ions/ acre or 3 dry tons/acre.
The four sludge application methods were explained to the
farmers at the 2 October 1975 public meeting. Results from six
farmers who completed the questionnaire on which method they
would prefer indicated that truck spreading was most pre-
ferred and tractor spreading was second most preferred.
These results are not conclusive enough to base a recom-
mendation on because of the few respondents and because the
farmers have actually seen only truck spreading in opera-
tion. It is expected that initially truck spreading will be
most acceptable to the farmers because it is flexible and
does not require their labor. After the farmers have seen
the advantages of soil injection and tractor spreading,
though, many should accept those methods also. From the
District's point of view, it may be best to first use mainly
trucks, even though the cost would be higher, in order to
build a market for sludge reuse. After a market is estab-
lished and some permanent on-farm facilities are arranged,
then the District should promote the less costly tractor
spreading and more environmentally acceptable soil injection
methods.
It is recommended that in the first year of operation, MMSD
purchase equipment for one soil injection system and one
tractor spreading system and enough truck spreaders to
7-25
-------
handle land application of most of the sludge. The soil
injector and tractor spreader systems would primarily be
used for demonstrations in the first year. The combined
systems' capacity should be sized to handle the amount of
sludge produced by the treatment plant. Net recovery of
sludge from the lagoons is not expected to be possible until
the market for sludge grows in the second and third years.
Then, as farmers begin to accept the soil injection and
tractor spreading methods, these types of equipment should
be purchased to match the increasing total sludge handling
requirements. The District should by then have received
commitments from some farmers and have constructed some
permanent on-farm facilities. The permanent on-farm facil-
ities, such as small lagoons and pipelines across fields,
are desirable for most efficient soil injection and tractor
spreader operations.
7.6 COMPARISON OF SLUDGE REUSE PROGRAMS
Farmer Acceptance
The farmers at the second farm community meeting were asked
by questionnaire which type of reuse program they would
prefer: Program 1, sludge supplied by MMSD at the farmer's
request; Program 2, lease land to MMSD for 1 year; or Pro-
gram 3, combination of Programs 1 and 2. Five out of six
respondents preferred Reuse Program 1. One farmer indicated
he would prefer Program 3. Sludge Reuse Program 2 apparently
is not acceptable to the farmers and therefore was not
considered further in this study.
Reuse Program 1 has been shown by the questionnaire and by
the interest in the existing sludge reuse program to be most
acceptable to the farmers. Reuse Program 3 will apparently
be acceptable to only a very few farmers. These few farmers
would most likely consider leasing only a part of their land
to the District for sludge application.
Cost Comparison
The only major cost differences between Reuse Programs 1 and
3 are the cost of leasing land for sludge application and
the cost of the sludge handling system. The cost of leasing
land would occur only in Program 3. To realize the cost
saving feature of Program 3, that of providing a lower
capacity sludge handling system, requires a large amount of
land available for leasing every year. Indications are that
few farmers will want to lease their land for sludge applica-
tion. Therefore, the sludge handling system would have to
7-26
-------
be designed for the same capacity in Program 3 as in Program 1.
Since Program 3 has the added expense of leasing land, but
no offsetting cost saving. Reuse Program 1 will be more cost
effective.
Recommended Sludge Reuse Program
Sludge Reuse Program 1, market all sludge to farmers, is the
best apparent program based upon farmer acceptance, relia-
bility, and costs.
Program 2, leasing land for sludge application, is not
suitable because it would not be acceptable to enough farmers.
Reuse Program 3, combination of Programs 1 and 2, is not
cost effective compared to Program 1. However, the concept
of leasing land from farmers should not be completely abandoned,
Even though it would cost extra to lease land for sludge
application, this may become necessary if the sludge supply
greatly exceeds the demand.
7-27
-------
8.1 REUSE PROGRAM DESCRIPTION
8.2 PROGRAM MANAGEMENT
8.3 MONITORING PROGRAM
8.4 MARKETING PROGRAM
8.5 SLUDGE HANDLING FACILITIES
8.6 REUSE PROGRAM COST
RECOMMENDED Q
SLUDGE REUSE PROGRAM O
-------
Chapter 8
RECOMMENDED SLUDGE REUSE PROGRAM
The recommended sludge reuse program, its management, opera-
tion, and costs are described in this chapter.
8. 1 REUSE PROGRAM DESCRIPTION
The initial reuse program should consist of marketing liquid
anaerobically digested sludge to farmers near the Nine
Springs Sewage Treatment Works. The District should manage
the program and provide for distribution and application of
the sludge to land. The sludge will be stabilized by anaero-
bic digestion to make it acceptable for land application.
The sludge from both the existing lagoons and from the
treatment plant will be disposed of by this program. The
lagoons will be abandoned for sludge disposal as described
in Chapter 5.
Seasonal storage of the treatment plant sludge will be
provided in the west side of Lagoon 1. The sludge now in
the existing large lagoons will be removed and applied to
farmland. This will allow the lagoons, which have been a
threat to the environment of the marsh and downstream
waterways, to return to a natural and safe condition.
The sludge will be transported to farmland initially by
tanker trucks and possibly later by pipeline. The sludge
will be applied to farmland by three main methods: truck
spreader, soil injector, and tractor spreader. The District
will be responsible for managing and monitoring the sludge
reuse program. The District will maintain control over
sludge reuse to ensure that the requirements for site
location, application rates and methods, and site management
as described in this report will be followed. The District
control of sludge reuse will be in the form of site inspec-
tions, site monitoring, and control of sludge handling
facilities.
8.2 PROGRAM MANAGEMENT
The reuse program operation and methods of reuse must be
managed by MMSD to ensure orderly, efficient operation and
environmentally acceptable land application. The major
components of program management will be a program manager.
8-1
-------
initial farmer interview and site inspection, rate determin-
ation, sludge application, and recordkeeping.
Program Manager
The District should appoint a person to manage the sludge
reuse program. The reuse program manager will be respon-
sible for overseeing the required sludge handling facilities,
developing and maintaining a market for the sludge, sched-
uling sludge distribution and application, farmer contact,
performing site inspection, and directing the monitoring
program. This will require a full-time position for the
program. The program manager must be able to relate to the
farmers, be familiar with Dane County agriculture, and be
enthusiastic about the program.
The manager must keep abreast of the latest technology of
sludge reuse in agriculture in order to make needed changes
in the reuse program. He should review the monitoring data
to detect potential problems. When an apparent or potential
problem develops, the program manager must be able to remedy
it or know whom to ask for assistance.
Initial Interview and Site Screening
When a farmer first contacts the District and requests that
sludge be applied to his land, the program manager should
set up an informal interview. At this interview, the farmer
will indicate his land location on a suitability map devel-
oped from the soil suitability classification for sludge
reuse which is contained in Appendix C. The program manager
will determine from the map how suitable the farmer's land
is for sludge reuse. If the farmer's land is suitable, the
next step will be to open a set of records under the
farmer's name. These records must include the farmer's
name, address, phone number, and field locations. The
farmer's fields should be outlined on small Agricultural
Stabilization and Conservation Service (ASCS) maps, and each
field should be denoted by a field number. Thereafter, each
field can be referred to by farmer's name and field number.
The ASCS field maps should be used by the program manager
when he checks the site conditions. Examples of record
sheets and field map are given in Appendix D.
After the initial interview and before sludge is applied to
the farmer's land, the program manager should walk over each
field on which sludge will be applied to visually check the
site and surrounding conditions. He should determine buffer
widths and areas requiring special management for erosion
8-2
-------
control and mark these on the file copy of the ASCS map. He
should also determine the location of all water supply wells
on and within 500 feet of the site. These wells should also
be denoted on the ASCS map and this information used for
ground-water monitoring. In determining buffer widths, the
program manager should also contact all residents bordering
the sludge application site to explain the sludge reuse
methods and to ask their permission to apply sludge within
200 feet of their home or garden. The program manager will
use a checklist to be sure that the site meets all criteria
for sludge application. An example checklist is contained
in Appendix D.
During the initial interview and site inspection, the program
manager should explain to the farmer the importance of using
careful management and the reasons for the buffer areas of
no sludge application. An ASCS map showing buffer areas and
other areas of special concern should be given to the farmer
so that he can plan his farming and fertilizing operations.
If possible, the interview and site inspection should be
performed a few months before sludge is needed and should
cover all the farmer's land, not just the portion using
sludge that year.
Sludge Application Rate Determination
Tables 6-5 and 6-6 gave suggested total and annual sludge
application rates based upon certain assumptions which were
explained in Section 6.3. In the sludge reuse program, the
application rates should be determined according to each
field condition and its management. Before sludge is applied
the first time, the soil should be tested for cation exchange
capacity (CEC) and background heavy metals. The CEC of the
unsludged soil and the zinc equivalent method will be used
to determine the total allowable sludge application rate as
shown in Appendix D. As explained in Chapter 6, the total
application limits determined by this method are very conser-
vative. Before the preliminary total application rate
limits are reached, in 30-60 years, more research results
should be available to better determine allowable rates.
On sites which have had sludge applied in the past, the
total application limits should be checked against the
amount already applied. If the application rate is excessive,
no additional sludge should be applied to those sites.
The annual sludge application rates should be based upon
results of the University of Wisconsin Soil Testing and
Fertilizer Recommendation program. This annual soil sampling
8-3
-------
program will be required as part of the soil monitoring
program which will be explained later in this chapter. The
fertilizer rate recommendations from the University of
Wisconsin Extension program will be used in determining the
sludge application rate. Example computations of annual
sludge application rates are given in Appendix D.
Recordkeeping
The District should keep records of the dates, locations,
and rates of sludge application on every field. The date of
sludge application can be used with sludge monitoring data
to determine the characteristics of the sludge applied to
the land. The location should be denoted by farmer name and
field number. The rate of sludge application in tons dry
solids per acre should also be recorded. This must be done
carefully so that the total amount of sludge applied to each
field can be determined long after the data are recorded.
An accumulated total of sludge applied to every field should
also be kept to determine when the total limit is reached.
A sludge application record sheet similar to that shown in
Appendix D should be used for each field. Copies of the
record sheets should be made available to the farmer.
The monitoring program records will be discussed in
Section 8.3.
8.3 MONITORING PROGRAM
The sludge reuse program should be monitored to protect the
environment, to provide farmer confidence in the program,
and to comply with regulatory agency requirements. The
program should include monitoring of the sludge, soils,
crops, and ground water. The monitoring program is explained
in detail in Appendix E. A summary of the monitoring program
is given here.
Sludge Monitoring
The objective of sludge monitoring is to define the quality
of the sludge, and from this the allowable loading rates
will be determined.
A detailed characterization of the existing Nine Springs
lagoon sludge has been determined as a part of this study.
The results of this characterization revealed that the
quality of the lagoon sludge was relatively uniform through-
out the lagoons with the exception of the nitrogen and
solids content. Therefore, only the total solids and ammonia
8-4
-------
and organic nitrogen need to be continually monitored in the
existing lagoons to determine application rates. Normally,
total Kjeldahl and ammonia nitrogen are measured and organic
nitrogen is computed as the difference between the two.
These should be measured daily in composite samples collected
as the sludge is removed from the lagoons for application to
land.
The quality of the sludge taken from the digesters, storage
lagoon, and on-farm lagoons may change from time to time.
Therefore, extra analyses must be performed on these sludges.
Daily composite samples should be obtained at these sources
whenever sludge is taken directly from them for land applica-
tion. These daily composite samples should also be analyzed
for solids content and ammonia and organic nitrogen. The
digester sludge should be monitored on a monthly grab
sample basis for solids content, ammonia and organic nitrogen,
total phosphorus, potassium, cadmium, zinc, copper, and
nickel. Quarterly grab samples should also be taken from
the digesters and storage lagoon for a complete characteriza-
tion. The complete characterization should include the
following: ammonia and organic nitrogen, total phosphorus,
potassium, total solids, total volatile solids, total soluble
salts, pH, iron zinc, copper, titanium, lead, barium, chro-
mium, manganese, nickel, tin, cadmium, molybdenum, cobalt,
aluminum, arsenic, boron, selenium, mercury, sulfate, alka-
linity, calcium, magnesium, and sodium. Techniques for
sludge sampling and analysis are discussed in Appendix E.
Soil Monitoring
The soil monitoring program should consist of two parts.
One will be to make use of the University of Wisconsin Agri-
cultural Extension soil testing, fertilizer recommendations,
and lime recommendations program. Another part will be to
determine background levels of sludge constituents which may
accumulate in the soil and to determine the factors used in
computing the total allowable sludge application rate.
The extension program consists of gathering soil samples
every year before the crop is fertilized and planted. The
extension service or their selected laboratories then
analyze the samples for available phosphorus, potassium,
organic carbon, and pH. They then make a recommendation for
fertilizer and lime application based upon the test results,
soil type, immediate past cultural practices, and crop to be
grown. As part of the MMSD sludge reuse program, the fertili-
zer and lime recommendations will be used to determine the
sludge application rate and will be required before each
8-5
-------
sludge application. MMSD should perform the soil sampling
and deliver the soil samples for testing.
The background level soil monitoring samples should be
collected before sludge is applied the first time. The
results of the first analysis will be recorded as background
levels and kept on file. All of the soil monitoring results
should be provided to the farmer as a service to aid in
determining basic soil fertility. The initial soil samples
should be analyzed for CEC, electrical conductivity, exchange-
able calcium, magnesium and sodium, total iron, aluminum,
zinc, copper, nickel, cadmium, molybdenum, mercury and
manganese, and boron. Techniques for sampling and testing
are discussed in Appendix E.
Crop Monitoring
The final effect of application to the land of the various
constituents in the sludge is on the plants grown on the
land. Plant tissue analysis will provide the most sensitive
and accurate assessment of these effects. Regular monitoring
by tissue analysis of the crops grown on the sludge applica-
tion sites will be used, along with the soils, sludge, and
ground-water monitoring, to determine the effects realized
by the sludge applications. The first crop sampling should
be performed during the first crop season following the
first sludge application. Thereafter, crop sampling will be
performed in the crop season following every third sludge
application. The plant tissue samples should be analyzed
for boron, cadmium, copper, manganese, mercury, nickel,
zinc, arsenic, chromium, cobalt, lead, molybdenum, selenium,
and vanadium. Techniques for sampling and testing are
discussed in Appendix E.
Ground-Water Monitoring
The ground-water monitoring program should consist of sampling
and analyzing the water from all wells or other ground-water
supplies on or within 500 feet of all sludge application
sites. An initial sample should be collected before the
first sludge application to establish background levels of
particular indicator and health problem sludge constituents.
The constituents monitored in the initial samples should
consist of MBAS, nitrate-nitrogen, total dissolved solids
(TDS), coliform, mercury, and arsenic. The main purpose of
the background testing is to protect MMSD and the farmer
against claims of ground-water degradation. Nitrate nitrogen
and TDS content of all wells or other ground-water sources
should also be measured every third year as a general indica-
tor of sludge constituents reaching the ground water.
8-6
-------
Techniques for sampling and testing of ground water are
discussed in Appendix E.
Records and Data Review
Collecting the data must not become the final step of the
monitoring program. Rather, the data must be reviewed
thoroughly each year to determine the effects of sludge
reuse and to be able to detect where problems may be develop-
ing. Suggested procedures to ensure adequate review of the
data are as follows:
• Tabulate or graph data when it is developed in a
form such that it can be quickly scanned to deter-
mine trends.
• Obtain University of Wisconsin Agricultural Exten-
sion review of soils and crop monitoring data.
• Prepare an annual report for the District Engineer
on the monitoring program which summarizes signi-
ficant differences or trends in constituents
measured.
• Provide copy of monitoring data report to WDNR for
their review.
• Provide copies of monitoring data to each sludge
user.
Monitoring Program Costs
The costs of each element of the monitoring program are
shown in Table B-13 in Appendix B. The costs will be at
their highest in the first few years of the reuse program
when most of the background soil and ground-water samples
will be analyzed. Also, after the existing lagoons are
emptied, the quantity of sludge available for reuse and
consequently the monitoring requirements will both decrease.
8.4 MARKETING PROGRAM
The District should work to develop a large reliable market
of farmers who want sludge applied to their land. Tools
which have been used successfully to market sludge are an
informational brochure, meetings with farmers, demonstration
plots, and the designation of a trade name.
8-7
-------
An attractive brochure which would inform the farmers on
what the product is, what its benefits to them would be, and
how they can obtain it should be prepared and distributed to
all farmers in the study area. An example is the BIOCRO
brochure which has proven highly successful.
The District should conduct a meeting in the winter of every
year to which all sludge users and prospective users are
invited. The meetings can be used to obtain farmers' sugges-
tions for better operation, to explain the program, and to
present new information. Farmers who have had sludge
applied to their land and are pleased with the results could
be asked to help the marketing effort by written or stated
endorsement of sludge use.
Interested farmer cooperations could assist in marketing
sludge by informing their members of the program, sponsoring
meetings, etc. Some cooperatives now have equipment suitable
for sludge application. Cooperative participation in the
reuse program should be allowed and encouraged to the extent
that MMSD can still maintain the control necessary to ensure
acceptable reuse methods.
The District should use demonstration plots to show the
effect of sludge application. One demonstration site should
be located near the Nine Springs Works which the program
manager can readily show to prospective sludge users. Other
plots should be set up in more distant areas where sludge is
used. The District should attempt to set up the demonstra-
tion plots on land of sludge users. Several farmers have
already offered to provide land for such plots. The demon-
stration plots should consist of an area with no fertilizer,
an area with sludge applied, and an area with commercial
fertilizer applied. The plots should be visible from fre-
quently traveled roads, and signs could be used to bring
attention to the plots. The plots need not necessarily be
set up in a scientific manner to prove effects with extensive
data, but rather just to demonstrate the general effect of
sludge use. The University of Wisconsin Extension should be
asked to cooperate in this program because county agents are
quite experienced in setting up demonstration plots.
The general public's image of the sludge reuse facilities
and operation should be enhanced and maintained. The sludge
should be given a trade name and logo such as HYDIG or
BIOCRO. It would be used on sludge handling equipment and
all promotional literature. This name would avoid the need
to call it sewage sludge, which admittedly is a negative
term.
8-8
-------
The public image of the program will also be influenced by
the program staff. The sludge handling field men and their
equipment will be in closest, most frequent contact with the
farmers and rural public. They must therefore be courteous
and helpful and keep the trucks and other sludge handling
equipment clean.
Many of the foregoing elements of a successful marketing
program have already been initiated as a part of this study.
This work should be expanded and continued. In summary, the
essential elements are:
• Public informational meetings.
• Use of a trade name.
• Use of an informational brochure for distribution.
• Maintenance of public image.
• Annual progress meetings with the farmers.
8.5 SLUDGE HANDLING FACILITIES
Sludge handling will include storage, transportation, distri-
bution, and land application. The number and types of
facilities required are difficult to estimate because of the
possible differences in size and location of the sludge
market. This discussion of facilities requirements is based
upon our best estimate of the development of an orderly
sludge reuse program. Plot plans of the major facilities
are shown on Figures 8-1 and 8-2.
The major sludge storage will be provided in the west half
of Lagoon 1 as described in Chapter 5.
The sludge distribution and land application facilities must
have capacity for the peak handling requirement. This peak
is expected to be about 35 percent of the amount of sludge
handled in a year and is expected to occur in April, before
corn planting. The amount and kind of sludge handling
equipment will increase and change as the market for sludge
grows. The amount of land to which sludge will be applied
each year is estimated as follows: first year, 2,000 acres;
second through tenth years, 5,000-6,000 acres; and after the
lagoons are emptied, 2,500-3,000 acres.
8-9
-------
FENCE LINE OF
EXPANDED
PLANT SITE
SLUDGE LAGOON NO. 1
DIKE ROAD
(GRAVELED)
DREDGE ACCESS
RAMP(PAVED)
TO SUPERNATANT
TREATMENT FACILITIES
AT TREATMENT PLANT,
DREDGE DOCK
SLUDGE PUMP STATION,
TOILET & SHOWER
TRUCK
PARKING
AREA
(PAVED)
EXISTING
TREES TO
REMAIN
SLUDGE LOADING
SUPERNATANT
WET WELL
TANKER TRUCK
SUPERNATANT
RETURN
PIPELINE
BADGER ROAD
.89166.0
100
SCALE IN FEET
200
FIGURE 8-1
SLUDGE DISTRIBUTION FACILITIES
SITE PLAN
MADISON METROPOLITAN
SEWERAGE DISTRICT
MADISON, WISCONSIN
CHJM
"HILL!
------- |