Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the
DAIRY PRODUCT
PROCESSING
Point Source Category
May 1974
>y
&
^ U.S. ENVIRONMENTAL PROTECTION AGENCY
* Wasliington, D.C. 20460
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DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
for the
DAIRY PRODUCTS PROCESSING
POINT SOURCE CATEGORY
Russell E. Train
Administrator
James L. Agee
Acting Assistant Administrator for Water and Hazardous Materials
Allen Cywin
Director, Effluent Guidelines Division
Richard Gregg
Project Officer
May 1974
Office of Water and Hazardous Materials
Office of Air and Water Programs
United States Environmental Protection. Agency
Washington, D.C. 20460
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402- Price ti.OS
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Abstract
This document presents the findings of an extensive study of
the dairy products processing industry by A. T. Kearney, Inc. for
the Environmental Protection Agency for the purpose of developing
effluent limitations guidelines. Federal standards of
performance, and pretreatment standards for the industry, to
implement Sections 304, 306, and 307 of the "Act."
Effluent limitations guidelines contained herein set forth
the degree of effluent reduction attainable through the
application of the best practicable control technology currently
available and the degree of effluent reduction attainable through
application of the best available technology economically
achievable which must be achieved by existing point sources by
July 1, 1977, and July 1, 1983, respectively. The Standards of
Performance for new sources contained herein set the degree of
effluent reduction which is achievable through the application of
the best available demonstrated control technology, processes,
operating methods, or other alternatives.
The development of data and recommendations in the document
relate to the twelve subcategories into which the industry was
divided on the basis of the levels of raw waste loads and
appropriate control and treatment technology. Separate effluent
limitations were developed for each subcategory on the basis of
the raw waste load as well as on the degree of treatment and
control achievable by suggested model systems.
Supportive data and rationales for development of the
proposed effluent limitations guidelines and standards of
performance are contained in this report. Potential approaches
for achieving the limitations levels and their costs are
discussed.
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TABLE OF CONTENTS
Section
II
III
IV
Conclusions
Size and Nature of the Industry
Industry Categorization
Pollutants and Contaminants
Control and Treatment of Waste Water
Recommendations
BOD5^ and Total Suspended Solids
PH
Method of Application
Multi-product Plants
Time Factor for Enforcement of the Guidelines
Introduction
Purpose and Authority
Summary of Methods
Basic Sources of Waste Load Data
General Description on the Industry
Industry Categorization
Introduction
Raw Materials Input
Processes Employed
Wastes Discharge
Finished Products Manufactured
Conclusion
Waste Characterization
Sources of Waste
Nature of Dairy Plant Wastes
Variability of Dairy Wastes
Waste Load Units
BOD
COD
Suspended Solids
pH
Temperature
Phosphorus
Nitrogen
Chloride
Waste Water Volume
Principal Factors Determining Dairy Waste Loads
Polluting Effects
1
1
1
2
2
3
3
3
3
5
7
9
9
10
11
13
33
33
33
33
34
34
35
39
39
39
43
43
47
47
49
52
52
52
53
53
53
53
57
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TABLE OF CONTENTS
(Cont'd)
Section
VI
VII
VIII
Pollutant Parameters 59
BOD£ 59
COD 60
Suspended Solids 61
pH 63
Temperature 64
Phosphorus 66
Nitrogen 67
Chloride 67
Control and Treatment Technology 71
In-Plant Control Concepts 71
Plant Management Improvement 71
Waste Monitoring 72
Engineering Improvements for In-Plant Waste
Control 72
Waste Management Through Equipment Improvements 73
Waste Management Through Systems Improvements 76
Waste Management Through Proper Plant Layout
and Equipment Selection 78
Waste Reduction Possible Through Improvement
of Plant Management and Plant Engineering 80
End-of-Pipe Waste Treatment Technology 92
Design Characteristics 94
Problems, Limitations and Reliability 94
Treatment of Whey 97
Advantages and Disadvantages of Various Systems 102
Management of Dairy Waste Treatment System 102
Tertiary Treatment 108
Pretreatment of Dairy Waste Discharged to
Municipal Sanitary Sewers 109
Performance of Dairy Waste Treatment Systems 113
Cost* Energy and Non-Water Quality Aspects 117
Cost of In-Plant Control 117
Cost of End-of-P1pe Treatment 122
Non-Water Quality Aspects of Dairy Waste Treatment 132
Energy Requirements 133
VI
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TABLE OF CONTENTS
"(Cont'd)
Section Page
IX Effluent Reduction Attainable Through the
Application of the Best Practicable Control
Technology Currently Available 135
Introduction 135
Effluent Reduction Attainable Through the
Application of the Best Practicable Control
Technology Currently Available 136
Identification of Best Practicable Control
Technology 136
Rationale for Selection of Best Practicable
Control Technology Currently Available 137
X Effluent Reduction Attainable Through the
Application of the Best Available Control Technology
Economically Achievable 141
Introduction , 141
Effluent Reduction Attainable Through the
Application of the Best Available Control
Technology Economically Achievable 142
Identification of Best Available Control
Technology Economically Achievable 144
Rationale for Selection of Best Available Control
Technology Economically Achievable 145
XI New Source Performance Standards 147
Introduction 147
Effluent Reduction Attainable in New Sources 148
XII Acknowledgements 149
XIII References , 151
XIV Glossary 161
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TABLES
Number Pagt
1 Effluent Limitation Guidelines for BOD5> and TSS 4
2 Standard Industrial Classification of the
Dairy Industry 13
3 Utilization of Milk by Processing Plants 16
4 Number of Dairy Plants and Average Production 17
5 Production of Major Dairy Products, 1963 & 1970 18
6 Employment of the Dairy Industry 18
7 Proposed Subcategorization for the Dairy
Products Industry 37
8 Upper Input Limitations for Designation as
a Small Plant 38
9 Composition of Common Dairy Products Processing
Materials 41
10 Estimated Contribution of Wasted Materials to
the BOD5_ Load of Dairy Waste Water (Fluid Milk Plant) 42
11 Summary of Calculated, Literature Reported and
Identified Plant Raw Waste BOD5. Data 48
12 Summary of Literature Reported and Identified
Plant Source BOD5;COD Ratios for Raw Dairy
Effluents 50
13 Summary of Identified Plant Source Raw Suspended
Solids Data 51
14 Summary of Literature Reported and Identified
Plant Source Raw Waste Water Volume Data 54
14A Summary of Literature Reported and Identified
Plant Source Raw Waste Water Volume Data (FPS Units) 55
14B Raw Waste Water Volume Attainable Through Good
In-Plant Control 56
15 Summary of pH, Temperature, and Concentrations of
Nitrogen, Phosphorus, and Chloride Ions -
Literature Reported and Identified Plant Sources 68
16 The Effect of Management Practices on Waste
Coefficients 84
17 Effect of Engineering Improvement of Equipment,
Processes and Systems on Waste Reduction 87
18 Recommended Design Parameters for Biological
Treatment of Dairy Wastes 96
19 Advantages and Disadvantages of Treatment Systems
Utilized in the Dairy Industry 103
20 Effect of Milk Lipids on the Efficiency of
Biological Oxidation of Milk Wastes 112
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TABLES
(Cont'd)
Number Page
21 Effluent Reductions Attained by Exemplary
Operations and Corresponding Guidelines
Limitations 114
22 General Comparison of Tertiary Treatment Systems
Efficiency 115
23 Plant Performance Data for the Tertiary Treatment
Plant at South Tahoe, California 116
24 Estimated Cost of Engineering Improvements of
Equipment and Systems to Reduce Waste 118
25 Tertiary Treatment Systems Cost 131
26 Biological System Cost Comparisons as Applied
in the Chemical Industry 132
27 Effluent Reduction Attainable Through Application
of Best Practicable Control Technology Currently
Available 139
28 Effluent Reduction Attainable Through Application
of Best Available Control Technology Economically
Achievable 143
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FIGURES
Number
1 Receiving Station - Basic Process 22
2 Fluid Milk - Basic Process 23
3 Cultured Products - Basic Process 24
4 Butter - Basic Process 25
5 Natural and Processed Cheese - Basic Process 26
6 Cottage Cheese - Basic Process 27
7 Ice Cream - Basic Process 28
8 Condensed Milk - Basic Process 29
9 Dry Milk - Basic Process 30
10 Condensed Whey - Basic Process 31
11 Dry Whey - Basic Process 32
12 Hourly Variations in ppn BOD5_, COD and
Waste Water for a Dairy Plant 44
13 Variation in Waste Strentgh of Frozen Products Drain for
Consecutive Sampling Days in One Month 45
14 Waste Coefficients for a Fluid Milk Operation Normal
Operation (#BCD/1000# Milk Processed, Gal. Waste
Water/1000# Milk Processed 82
15 Waste Coefficients After Installation of Engineering Advances
in a Fluid Milk Operation (#BCD/1000# Milk Processed, Gal.
Waste Water/1000* Milk Processed) 83
16 Fat Losses as a Function of Time During Start-up and
Shut-down of a 60,000 Pound/Hour HTST Pasteurizer .... 91
17 Recorrmended Treatment Systems for Dairy Waste Water .... 95
18 Tertiary Treatment of Secondary Effluent for Complete
Recycle 110
19 Capital Cost (August, 1971) Activated Sludge Systems
(For Dairy Wastewater) 123
20 Capital Cost (August, 1971) Trickling Filter Systems
(For Dairy Wastewater) 124
21 Capital Cost {August, 1971) Aerated Lagoon1(For
Dairy Wastewater) 125
22 Operating Costs (August, 1971) Activated Sludge System,
Trickling Filter System, and Aerated Lagoon (For
Dairy Wastewater) 126
23 Operating Costs (August, 1971) Activated Sludge, Trickling
Filter and Aerated Lagoon Systems (For Dairy
Wastewater) 127
xi
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SECTION I
CONCLUSIONS
Size and Nature of the Industry
The basic function of the dairy products processing industry is
the manufacture of foods based on milk or milk products.
However, a limited number of non-milk products such as fruit
juices are processed in some plants.
There are over 5,000 plants in the dairy products industry
located all over the United States. Plants range in size from a
few thousand kilograms to over 1 million kilograms of milk
received per day.
There are about 20 different basic types of products manufactured
by the industry. A substantial number of plants in the industry
engage in multi-product manufacturing, and product mix varies
broadly among such plants.
Industry Categorization
For the purpose of establishing effluent limitations guidelines
and standards of performance the dairy products industry can be
logically subcategorized in relation to type of product
manufactured. Available information permits a meaningful
segmentation into the following subcategories at this time;
Receiving stations
Fluid products
Cultured products
Butter
Cottage cheese and cultured cream cheese
Natural cheese and processed cheese
Ice cream, novelties and other frozen desserts
Ice cream mix
Condensed milk
Dry milk
Condensed whey
Dry whey
Factors such as size and age of plants, minor variations in
processes employed, and geographical location generally do not
have an effect that would justify additional subcategorization
based on the degree of pollutant reduction that is technically
feasible. However, a collateral economic study (conducted for
the Environmental Protection Agency by Development Planning and
Research Associates, Inc.) indicates that the costs of comparable
treatment facilities impose a severe economic impact on the
smaller plants in each subcategory. Thus, the subcategories
should be further segmented by size to permit employment by the
smaller plants of lesser technology that is within their
financial capabilities.
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pollutants and Contaminants
The most significant pollutants contained in dairy products plant
wastes are organic materials which exert a biochemical oxygen
demand and suspended solids. Raw waste waters from all plants in
the industry contain quantities of these pollutants that are
excessive for direct discharge without appreciable reduction.
The pH of many individual waste streams within a plant are
outside the acceptable range, but there is generally a tendency
for neutralization with commingling of waste streams. However,
adjustment of pH is easily accomplished and the final
discharge(s) from a plant should be kept within an acceptable
range.
Additional contaminants found in dairy plant wastes include:
phosphorus, nitrogen, chlorides, and heat. In general, control
and treatment of the primary pollutants (organics and suspended
solids) will hold these lesser pollutants to satisfactory levels.
In isolated cases where these pollutants may be critical they
should be handled on a case by case basis.
A major contributor to dairy waste BOD5 is dairy fat, which is
being treated successfully biologically. This is in contrast to
mineral based oil which inhibits the respiration of
microorganisms. The standard hexane soluble FOG (fats, oils, and
grease) test used presently does not differentiate between
mineral oil and dairy fat. Separate standards and tests should
be developed for these two parameters.
Control and Treatment of Waste Water
In-plant controls, including management and engineering
improvements, that are readily available and economically
achievable can substantially reduce waste loads in the dairy
industry. In many cases these controls can produce a net
economic return through by-product recovery or reduced cost of
waste treatment.
conventional end-of-pipe treatment technology is capable of
achieving a high degree of reduction when applied to the raw
wa stes of dairy plant s. Attainment of z ero dis charge by
complete recycle of waste waters, though a technical possibility
through employment of reverse osmosis, carbon filtration and
other advanced treatment techniques, is beyond the realm of
economic feasibility for most if not all plants in the industry.
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SECTION II
RECOMMENDATIONS
It is recommended that effluent limitation guidelines for
existing sources and standards of performance for new sources in
the dairy products industry be established for BOD5,, suspended
solids and pH. These limitations and standards are recommended
only for dairy plants discharging to navigable waters. For
dairies discharging to sanitary systems, municipalities should
adopt other standards that reflect their own particular
requirements.
1QD5 and Total Suspended Solids
Recommended effluent limitations guidelines and standards of
performance for BOD5 and total suspended solids in terms of the
average value for any consecutive thirty day period are set forth
in Table 1.
EH
It is recommended that the pH of any final discharge(s) be within
the range of 6.0-9.0.
Method of Application
Calculation of BOD5 Received.
It is recommended that in applying the guidelines and standards
the waste load of a particular plant be determined and compared
to the guidelines and standards. In doing so, it is imperative
that consistency be maintained in regard to the basis on which
the waste loads are developed.
To maintain consistency the calculation of the BOD5 received
(going into processes in the case of multi-product plants) must
be done on the following basis:
1, All dairy raw materials (milk and/or milk products) and
other materials (e.g. sugar) must be considered.
2. The BOD5 input must be computed by applying factors of 1.03
0.890 and 0.691 to inputs of proteins, fats and carbohydrate
respectively. Organic acids (such as lactic acid) when
present in appreciable quantities should be assigned the
same factor as carbohydrates. The composition of raw
materials may be obtained from the U.S. Department of
Agriculture Handbook No.8, Composition of Foods and
other reliable sources. Compositions of some common
raw materials are given in Table 8.
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Table 1
Effluent Limitation Guidelines for BOD5 and TSS
Subcategory (1)
Receiving Stations
Small
Other
Fluid Products
Small
Other
Cultured Products
Small
Other
Butter
Small
Other
Cottage Cheese
Small
Other
Natural Cheese
Small
Other
Ice Cream Mix
Small
Other
Ice Cream
Small
Other
Condensed Milk
Small
Other
Dry Milk
Small
Other
Condensed Whey
Small
Other
Dry Whey
Small
Other
NOTES: (1)
(2)
(3)
fJl
(5)
Limitations in kg/kkg BOD5 Input (2)
Level I('3) Level 11(4) Level 111(5)
BOD5 TSS BOD5 TSS BOD5
0.313 0.469 0.075 0.094 0.050
0.190 0.285 0.050 0.063 0.050
2.250 3.375 0.550 0.688 0.370
1.350 2.025 0.370 0.463 0.370
2.250 3.375 0.550 0,688 0.370
1.350 2.025 0.370 0.463 0.370
0.913 1.369 0.125 0.156 0.080
0.550 . 0.825 0.080 0.10 0.080
4.463 6.694 1.113 1.391 0.740
2.680 4.020 0.740 0.925 0.740
0.488 0.731 0.125 0.156 0.080
0.290 0.435 0.080 0.10 0.080
1.463 2.194 0.363 0.454 0.240
0.880 1.320 0.240 0.30 0.240
3.063 4.594 0.70 0.875 0.470
1.840 2.760 0.470 0.588 0.470
2.30 3.450 0.575 0.719 0.380
1.380 2.070 0.380 0.475 0.380
1.088 1.638 0.275 0.344 0.180
0.650 0.975 0.180 0.225 0.180
0.650 0.975 0.163 0.204 0.110
0.40 0.60 0.110 0.138 0.110
0.650 0.975 0.163 0.204 0.110
0.40 0.60 0.110 0.138 0.110
See Table 7 for definition of products included in
each subcategory.
See calculation of BOD5 below for derivation of
values for BOD5 received.
Best practicabTe control technology currently
available.
Best available technology economically achievable.
Standards of performance for new sources.
TSS
0 ,063
0.063
0.463
0.463
0.463
0.463
0.10
0.10
0.925
0.925
0.10
0.10
0.30
0.30
0.588
0.588
0.475
0.475
0.225
0.225
0.138
0.138
, 0.138
0.138
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Multi-Product Plants
The guidelines and standards set forth in Table 1 apply only to
single-product plants. It is recommended that limitations for
any multi-product plant be derived from Table 1 on the basis of a
weighted average, i.e., weighting the single-product guideline by
the BOD5 processed in the manufacturing line for each product.
That is:
Multi-product Limitation -
/Guideline (in kg/kkg or lb/100
[ For each single product sub-
Vcategory present in the plant
Number of kkg or 100 Ib
units of BODS input
for each single product
subcategory present
Examples of application of guidelines to multi-product plants are
as follows:
Type of Plant: Fluid Products, Cottage Cheese and Ice Cream
Raw Materials Processed (Avg. per Day)
Purchases
1. Whole Milk
2. 40% Cream
3. 30% Condensed Skim
U. Nonfat Dry Milk
5. sugar
400,000 lb(41,560 Ib of BODS)
20,000 Ib (7,750 Ib of BODS)"
16,000 Ib (3,520 Ib of BOD5)
2,000 Ib (1,480 Ib of BODS)
6,500 Ib (4,490 Ib of BOD5)
Intra-Plant Transfers (For Further Processing)
1.
2.
Skim Milk
36X Cream
50,000 Ib (3,660 Ib of BODS)
3,000 Ib (1,100 Ib of BOD5)
Determination of BOD5 Multi-Product Guideline, Level I (BPCTCA)
Subcategory and Input
1. Fluid Products
400,000 Ib Whole
Milk (41,560 Ib
of BOD5)
Total BOD5 Input 41,560 Ib
2. Cottage Cheese
50,000 Ib Skim
Milk (3,660 Ib of
BODS) 3,000 Ib
36% Cream (1,100
Ib of BODS)
Total BOD5 Input 4,760 Ib
Guideline Value
Guideline Discharge
0.135 lb/100 Ib
56.11 Ib
0.268 lb/100 Ib
12.76 Ib
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3. Ice Cream
16,000 Ib 30*
Condensed skim
(3,520 Ib of BODS)
20,000 Ib 40X Cream
(7,750 Ib of BOD5)
2,000 Ib Nonfat Dry
Milk
(1,480 Ib of BOD5)
6,500 Ib Sugar
(4,490 Ib of BOD5)
Total BOD5 Input 17,240 Ib
0.184 lb/J.00 Ib
31.72
Recommended Discharge for Total Plant = 100.59 lb of BOD5.
Type of Plant: Natural Cheese and Dry Whey
Raw Materials Processed (Avg. per Day)
Purchases
1. Whole Milk
2. 40% Solids Whey
500,000 lb (51,950 lb of BOD5)
30,000 lb (8,210 lb of BOD£)
Intra-Plant Transfers (For Further Processing)
1. Sweet Whey
2. 40% Solids Whey
455,000 lb (21,476 lb of BOD5)
75,860 lb (20,760 Ib of BODSj
Determination of BOD5 Multi-Product Guideline, Level I (BPCTCA)
Subcategorv and Input Guideline Valise
1. Natural cheese
500,000 lb Whole Milk
(51,950 lb of BOD5)
Total BOD5 Input 51,950 0.029 lb/100 lb
2. Condensed Whey
455,000 lb Sweet Whey
(21,476 lb of BODS)
Total BOD5 Input 21,476 lb
3. Dry Whey
105,860 lb 40X Solids
Whey
(28,970 lb of BOD5J
Total BOD5 Input 28,970 0.040 lb/100 lb
Recommended Discharge for Total Plant = 35.25 lb
0.040 lb/100 lb
Guideline Discharge
15.07 lb
8.59 lb
11,59 lb
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A second decision to be made in regard to multi-product plants is
that of size designation for determination of which guideline
limitation values, those for small or those for other, should
apply. If any single subcategory representation in a multi-
product plant exceeds the size limitations suggested for
designation as a small single product plant of that subcategory,
irrespective of the size of the remaining subcategory
representations the multi-product plant should not be designated
as small. If none of the individual subcategory representations
exceed the size limitations for their corresponding
subcategories, it is recommended that each representation be
expressed as a fraction of the corresponding subcategory
limitation, and if the sum of the fractions does not exceed 1.5,
the facility should be designated a small multi-product plant.
That is
Subcateaorv Representation \^5 1.5 Facility is a Small
Subcategory Size Limitation/ Multi-Product Plant
For subcategory size limitations see Section IV.
Time Factor for *
Enforcement^of^/the Guidelines
The proposed effluent limitations and performance standards are
based on thirty-day averages. For purposes of enforcement and
determination of violations, daily maximums as multiples of the
thirty-day average should apply, reflecting variability
attributable to the reliability of technology. In the case of
best practicable control technology currently available, daily
maximum values of two times and two and one-half times the
thirty-day averages are recommended for small plants and larger
plants respectively. For best available technology economically
achievable and new source performance standards daily maximum
values of two times the thirty-day averages are recommended for
all plants.
Because of the hourly and daily fluctuations of waste
concentrations and waste water flows in the dairy products
industry, waste loads should be measured on the basis of daily
proportional composite sampling. This is particularly true for
plants utilizing treatment facilities with relatively short
retention times (e.g., activated sludge) which result in a
greater tendency for influent fluctuations to be reflected in the
effluent.
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SECTION III
INTRODUCTION
Purpose and Authority
Section 301 (b) of the Act requires the achievement by not later
than July 1, 1977, of effluent limitations for point sources,
other than publicly owned treatment works, which are based on the
application of the best practicable control technology currently
available as defined by the Administrator pursuant to Section
304(b) of the Act. Section 301 (b) also requires the achievement
by not later than July 1, 1983, of effluent limitations for point
sources, other than publicly owned treatment works, which are
based on the application of the best available technology
economically achievable which will result in reasonable further
progress toward the national goal of eliminating the discharge of
all pollutants, as determined in accordance with regulations
issued by the Administrator pursuant to Section 304 (b) of the
Act. Section 306 of the Act requires the achievement by new
sources of a Federal standard of performance providing for the
control of the discharge of pollutants which reflects the
greatest degree of effluent reduction which the Administrator
determines to be achievable through the application of the best
available demonstrated control technology,, processes, operating
methods, or other alternatives. including where practicable, a
standard permitting no discharge of pollutants.
Section 304 (b) of the Act requires the Administrator to publish
within one year of enactment of the Act, regulations providing
guidelines for effluent limitations setting forth the degree of
effluent reduction attainable through the application of the best
practicable control technology currently available and the degree
of effluent reduction attainable through the application of the
best control measures and practices economically achievable
including treatment techniques, process and procedure
innovations, operation methods and other alternatives. The
regulations proposed herein set forth effluent limitations
guidelines pursuant to Section 304 (b) of the Act for the dairy
products processing industry.
Section 306 of the Act requires the Administrator, within one
year after a category of sources is included in a list published
pursuant to Section 306 (1) (A) of the Act to propose regulations
establishing Federal standards of performances for new sources
within such categories. The Administrator published in the
Federal Register of January 16, 1973 (38 F.R. 1624), a list of 27
source categories. Publication of the list constituted
announcement of the Administrator's intention of establishing,
under Section 306, standards of performance applicable to new
sources within the dairy industry which was included within the
list published January 16, 1973.
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Summary of Methods Used for Development of the Effluent
^imitations Guidelines and standards of Performance
The effluent limitations guidelines and standards of performance
proposed herein were developed in the following manner. The
dairy products processing industry was first analyzed for the
purpose of determining whether separate limitations and standards
are appropriate for different segments within the industry. Such
analysis was based upon raw material used, product produced,
manufacturing process employed, and other factors. The raw waste
characteristics for each subcategory were then identified. This
included an analyses of (1) the source and volume of water used
in the process employed and the sources of waste and waste waters
in the plant; and (2) the constituents (including thermal) of all
waste waters including toxic constituents and other constituents
which result in taste, odor, and color in water or aquatic
organisms. The constituents of waste waters which should be
subject to effluent limitations guidelines and standards of
performance were identified.
The full range of control and treatment technologies existing
within each subcategory was identified. This included an
identifaciton of each distinct control and treatment technology,
including both in-plant and end-of-process technolgies, which are
existent or capable of being designed for each subcategory. It
aIso included an identification in terms of the amount of
constituents (including thermal) and the chemical, physical, and
biological characteristics of pollutants, of the effluent level
resulting from the application of each of the treatment and
control technologies. The problems, limitations and reliability
of each treatment and control technology and the required
implementation time were also identified. In addition, the non-
water quality environmental impact, such as the effects of the
application of such technologies upon other technology and the
required implementation time were also identified. In addition,
the non-water quality environmental impact, such as the effects
of the application of such technologies upon other pollution
problems, including air, solid waste, noise and radiation were
also idenitified. The energy requirements of each of the control
and treatment technologies were identified as well as the cost of
the application of such technologies.
The information, as outline above, was then evaluated in order to
determine what levels of technology constituted the "best
practicable control technology currently available," "best
available technology, processed, operating methods, or other
alternatives." In identifying such technologies, various factors
were considered. These included the total cost of application of
technology in relation to the effluent reduction benefits to be
achieved from such application, the age of equipment and
facilities involved, the process employed, the engineering
aspects of the application of various types of control
techniques, process changes, non-water quality environmental
impact (including energy requirements) and other factors.
10
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The data for identification and analyses were derived from a
number of sources. These sources included EPA research in-
formation, published literature, a voluntary questionaire issued
by the Dairy Industry Committee, qualified technical
consultation, and on-site waste sampling, visits, and interviews
at dairy food processing plants throughout the United States.
All references used in developing the guidelines for effluent
limitations and standards of performance for new sources reported
herein are included in Section XIV of this document.
Basic Sources of Waste Load Data
Prior Research
At the outset of this study, it was recognized that most of the
information on dairy food plant wastes available as of 1971 had
been collected and reviewed in two studies prepared for EPA:
1. "Study of Wastes and Effluent Requirements of the Dairy
Industry," July 1971, by A.T. Kearney, Inc., for the Water
Quality Office, EPA.
2. "Dairy Food Plant Wastes and Waste Treatment Practices,
"March 1971, ty Department of Dairy Technology, The Ohio State
University, for the Office of Research and Monitoring, EPA.
The purpose of the 1971 Kearney study was to establish an
informational background and recommend preliminary effluent
limitation guidelines for the dairy industry. The Ohio State
University study was a "state-of-the-art" report that set forth
in great detail practically all available technical knowledge on
dairy products processing. Dr. W. James Harper, the lead
investigator for the Ohio state University study, served as a
consultant to A. T. Kearny for the preparation of its report for
the Water Quality Office, and essentially the same data base was
utilized in both studies.
Sources of Data For This Study
Although many of the key factors affecting waste loads had been
identified in the aforementioned reports and other technical
literature, it was recognized that an expanded and refined data
and informational base was needed to meet requirements associated
with development of effluent limitations guidelines for the dairy
products industry. Furthermore, it is imperative that all data
used for development of guidelines be of a "verifiable" nature
(i.e., the result of testing in identified plants that could be
available for verification of data if necessary), and much of the
data in the technical literature is not identified as to specific
source. A concerted effort was devoted to a program to develop
new and verifiable data that would supplement or even supplant
the data available in the technical literature.
11
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The body of quantitative data on wastes available for
development of effluent limitations guidelines that resulted from
this program was an aggregate of portions obtained from the
following sources;
1. In-plant sampling of waste streams at selected dairy
plants undertaken by independent certified laboratories under the
direction of A.T. Kearney and with the assistance of dairy plant
managements.
2. In-plant sampling at selected plants performed by the
dairy companies utilizing contractors or company technical
personnel, and with quality control assured by direction and
observation of A.T. Kearney or EPA.
3. Data obtained from State and Municipal agencies (e.g.,
the Metropolitan Sanitary District of Greater Chicago) which have
monitored the waste of selected dairy plants for regulatory
purposes.
4. Data supplied by dairy companies which are the result of
sampling programs conducted by the companies since the time of
Kearney's 1971 study.
5. Plant waste survey data developed by independent
research organizations (e.g.. North Carolina Sate University) at
selected dairy operations in the last two years.
6. Data furnished by the dairy industry to Kearney and Ohio
Stae University during the 1971 studies for EPA in coded Form,
but through company cooperation now identified as to specific
plant source with pertinent operational parameters furnished.
Quality of the Data
Because of the high variability of dairy plant wastes in
hydraulic load and strength, both during a day and from day to
day, it is recognized that a composite made up of samples taken
at hourly intervals or over a few days may yield values that
depart considerably from true average loads. However, the
variance that may exist because of low frequency of sampling or
insufficient number of days in the sampling period decreases as
the number of data points (one-day composites) in the data base
increases.
While the approximately 150 plants included in the verifiable
data base constitute only 3% of the total number of plants within
the dairy products industry, it should be noted that the data
base is the most extensive one of its nature compiled to date.
The number of individual product manufacturing lines represented
in aggregate is much greater than the number of plants, since
many of the facilities are multi-product plants. Moreover, two
additional factors should be borne in mind. The major thrusts in
developing the data base were directed toward obtaining
information on exemplary operations and securing representation
of the range of size, age and other variables encountered in
plants manufacturing each type of finished product.
-------
Several control measures were imposed on the sampling program to
maintain the quality of the waste load data. All analyses
employed approved standard methods conducted under acceptable
laboratory quality control. Flow-weighted composite sampling was
used in all but a few cases, with the time interval between
taking all aliguots ranging from 2 to 60 minutes. Exceptions
were made only when information from a particular plant was
highly desirable and installation of flow-proportioned composite
sampling equipment was not possible. Constant volume sampling at
set intervals was accepted in some cases when there was
indication that variation of flow was within the limits of error
of many field-flow measurement devices.
The number of days in any one sampling period at a plant ranged
from 1 to 10 days, with the vast majority of the cases entailing
3 or more days. In a number of cases the data on plants that
was furnished by the companies covered a long-term monitoring
program.
/
General .Description of_the Industry
Production Classification
The industrial category covered by this document comprises all
manufacturing establishments included in Standard Industrial
Classification (SIC) Group No. 202 ("Dairy Products"), and "milk
receiving stations primarily engaged in the assembly and
reshipment of bulk milk for the use of manufacturing or
processing plants" (included in SIC Industry No. 5043) .
The common characteristic of all plants covered by this
definition is that milk or milk by-products, including whey and
buttermilk, are the sole or principal raw materiasl employed in
the production processes. A comprehensive list of the types of
products manufactured by the industry, as classified by the
Office of Statistical standards,appear in Table 2,
TABLE 2
STANDARD INDUSTRIAL CLASSIFICATION
OF THE DAIRY INDUSTRY
(AS DEFINED BY THE OFFICE OF STATISTICAL STANDARDS)
Group
202
Industry
DAIRY PRODUCTS
This group includes establishments primarily
engaged in; (1) manufacturing creamery
butter;natural cheese; condensed and
evaporated milk; ice cream and frozen
desserts; and special dairy products, such
as processed cheese and malted milk: and
(2) processing (pasteurizing homogenizing,
vitaminizing, bottling fluid milk and cream
13
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2021
retail for wholesale or retail distribution.
Independently operated milk receiving
stations primarily engaged in the
assembly and reshipment of bulk milk for
the use of manufacturing or processing
plants are included in Industry 5043.*
Creamery Butter
Establishments primarily engaged in
manufacturing creamery butter.
Anhydrous milkfat
Butter, creamery and whey
202
2022
Cheese. Natural and processed
Establishments primarily engaged in
manufacturing all types of natural
cheese (except cottage cheese—
Industry 2026), processed cheese,
cheese foods, and cheese spreads.
Cheese, all types and varieties
except cottage cheese
Cheese, natural
Cheese, processed
Cheese spreads, pastes, and
cheeselike preparations
Processed cheese
Sandwich spreads
2023
Condensed and Evaporated Milk
Establishments primarily engaged in
manufacturing condensed and evaporated
milk and related products, including ice
cream mix and ice milk mix made for sale
as such and dry milk products.
Baby formula, fresh, processed and
bottled
Buttermilk; concentrated, condensed,
dried, evaporated, and powdered
Casein, dry and wet
Cream; dried, powdered, and canned
Dry milk products; whole milk;
nonfat milk;buttermilk; whey and
cream
Ice milk mix, unfrozen; made in
condensed and evaporated milk
H
-------
plants
Lactose, edible
Malted milk
Milk; concentrated, condensed,
dried evaporated and powdered
Milk, whole; canned
Skim milk: concentrated, dried,
and powdered
Sugar of milk
Whey: concentrated, condensed,
dried evaporated, and powdered
202
2024
2026
Ice Cream and Frozen^Desserts
Establishments primarily engaged in
manufacturing ice cream and other
frozen desserts.
Custard, frozen
Ice cream: bulk, packaged, molded,
on sticks, etc.
Ice milk: bulk, packaged, molded,
on sticks, etc.
Ices and sherberts
Mellorine
Mellorine-type products
Parfait
Sherberts and ices
Spumoni
Fluid Milk
Establishments primarily engaged in
processing (pasteurizing, homgenizing
vitaminizing bottling) and distributing
fluid milk and cream, and related products.
Buttermilk, cultured
Chee se, cottage
Chocolate milk
Cottage cheese, including pot,
bakers', and farmers * cheese
Cream, aerated
Cream, bottled
Cream, plastic
Cream, sour
Kumyss
Milk, acidophilus
Milkr, bottled
Milk processing (pasteurizing,
homogenizing, vitaminizing,
bottling) and distribution:
with or without manufacture of
15
-------
dairy products
Milk products, made from fresh
milk
Route salemen for dairies
Whipped cream
Yoghurt
zoolak
Source: Standard Industrial Classification Director
In recent years, many establishments classified within the dairy
industry have also engaged in manufacturing other than products
based on milk or milk by-products. Such is the case of fluid
milk plants in which filling lines are also utilized for
processing fruit juices, fruit drinks and other flavored
beverages. The guidelines developed in this study are not
intended to cover processes where other than milk-based products
are involved.
Effluent limitations for those cases involving non-dairy products
are more logically handled by application of guidelines developed
for appropriate industries (e.g., beverages or fruits) or on an
individual basis with consideration given to the BOD5 of the raw
materials, the loss of materials and the hydraulic load that is
consistent with levels of treatment and control established for
the dairy products industry.
Number of Plants and Volume Processed
In 1970, there existed approximately 5,350 dairy plants in the
United states, which processed about 51 billion kg of milk, or
96% of the milk produced at the farm. The utilization of milk to
manufacture major types of products was as given in Table 3.
TABLE_3
Utilization of Milk by Processing Plants (1970)
Percent of
Use Total Milk Produced
Fluid Products
Butter
Natural Cheese
Ice Cream and other Frozen Products
Evaporated Milk
Cottage Cheese
Dry Milk
45.1
22.2
17.0
11.4
2.8
1.0
100.0
The dairy industry comprises plants that receive anywhere from a
few thousand to over 1 million kg of milk and milk by-products
16
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per day. The plants are located throught the country, with
regional concentrations in Minnesota, Wisconsin, New York, Iowa
and California.
Trends
Significant trends in the U.S. dairy industry which bear on the
waste disposal problem include; (a) a marked decrease in the
number of plants and increased production per plant (b) changes
in the relative production of various types of dairy foods, (c)
increasing automation of processing and handling facilities, and
(d) changes in location of the plants.
Plants and Production
Over the past 25 years, dairy food processing plants in the
United States have been decreasing in number and increasing in
size. The main reasons for this trend are economic and
technolgica1, including unit cost reductions attainable by
processing larger volumes and improvements in
transportation,storage facilities and product shelf-life which
allow the products to be handled over longer distances and longer
periods.
The change in number of plants and processsing
past decade is reflected in Table 4 below.
capacity in the
TABLE 4
Number of Dairy Plants and Average Production
Type of^Product
Fluid Products 6
Cottage Cheese
Butter
Cheese
Evaporated 6
Dry milk
Ice Cream 6
Frozen Dessert
Number of Plants
1163
4,619
1,320
1,283
281
1x081,
8,584
197Q
2,824
619
963
257
689
5,352
Average Annual Production
Per Plant
Million kg (Ib) of Product
1963
1970
5.6 (12.3) 9.7 (21.3)
0.5 (1.1)
0.5 (1.1)
0.7 (1.5)
1.0 (2.2)
18.0 (39.6)19.1 (42.0
liO (6.6) 6..? (14.7)
28.3 (62.3)37.2 (81.8)
Table 5 reflects the trends in production of dairy products.
While production of butter and condensed products has been on the
decline, the production of natural cheese, cottage cheese, ice
cream, and fluid products has been increasing:
17
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TABLE 5
Production of Major Dairy Products, 1963 and 1970
Type of Product
Total Production
Millions of Kilograms(Pounds)
1963
Butter
Condensed and Dry Products
Cheese
Ice Cream & Frozen Desserts 4,050
Cottage Cheese 410
Fluid Products 25^550
36,416
636 (1,399)
5,050 (11,110)
730 ( 1,606)
( 8,910)
( 902)
(56,110)
1970
500 (1,050)
4,910 (10,802)
1,000 ( 2,200)
4,590 (10,098)
450 ( 990)
27tO_5j) (59,510)
36,500
Percent
Change
-3X
37X
13X
in
6X
It is important to note that those sectors of the dairy products
industry that are experiencing the highest rates of growth (ice
cream, frozen deserts, and cottage cheese) are also those which
have been shown to produce proportionally the largest waste.
Because it is produced in such large volumes and is relatively
low in solids content, whey has long posed a utilization problem
for the industry. The problem has increased as plants have
become larger and more distant from farming areas where whey can
be used directly as feed. Cottage cheese whey represents the
more serious problem because its acid nature limits its
utilization as feed or food.
It is estimated that between 3056 to SOX of the whey produced is
not processed into a finished product, but fed raw to livestock
or discarded in various ways as waste, some of which goes to
municipal treatment plants. Because of its microbial inhibiting
effect, unless whey is diluted with other wastes it can
potentially shock the receiving treatment system.
Plant Automation
As plants have increased in size there has been a tendency to
mechanize and automate many processing and handling operations.
This is reflected by the decreasing employment in the industry as
shown in Table 6..
Type of Plant
Employment in the Dairy Industry
(Thousands)
Total^ Employment
Employment
per million kkg.
Produced Annually
1963
1970
1963
1970
18
-------
Butter,
Cheese
Condensed 6 Dry
Products
ice Cream S Frozen
Desserts
Fluid Products 6
Cottage Cheese
12.0
17.9
12.2
29.1
185.0
7.2
21.1
10.7
22.4
140.7
18.7
24.6
2.4
7.3
7.0
14.3
20.9
2.2
4.8
5.1
The principal technoligical developments that are being widely
applied throughout the industry and which have significance in
relation to waste loads include:
1. Receiving milk in tank trucks, with automated rinsing and
cleaning of the tanks at the plant.
2. Remote-controlled,, continous-flow processing of milk ;at rates
up to 45,000 kilograms per hours, with automatic standardizing of
fat content.
3. Use of cleaned-in-place (CIP) systems that do not require
daily dismantling of the equipment and utilize contolled amounts
of detergents and sanitizing chemicals.
4. High speed, automatic filling and packaging operations
5. Automated materials handling by means of conveyors,
and stackers
casers
Although automation can theoretically provide for lower waste
loads through in-plant waste control engineering, at the present
time other factors have greater influence in the waste loads, as
discussed later in this report.
Plant Location
As dairy plants have increased in size, the trend has been to
receive milk from and distribute products to larger areas. As a
result, the location of a plant has become independent of the
immediate market place. Quite often, the prevailing factor has
been to select a site with covenient access to major highway
system covering the area serviced, usually at some distance from
the larger urban centers.
The problem of waste disposal has frequently been given little
attention in selecting the location of large new plants. A
number of facilities with waste loads up to 3,500 kg BODS/day
have been constructed in suburban areas of cities of under 50,000
population. Where such plants utilize the municipal sewage
treatment facility they may become the largest contributor to the
municipal system, imposing on it the problems that are typically
associated with dairy wastes, such as highly variable hydraulic
19
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and BOD5 loads and the risk of shock-loads when whey is
discharged without equalization.
Processing Operations
A great variety of operations are encountered in the dairy
products industry, but in oversimplication they can be considered
a chain of operations involving receiving and storing of raw
materials, processing of raw materials into finished products,
packaging and storing of finished product, and a group of
ancillary operations (e.g., heat transfer and cleaning) only
indirectly involved in processing of materials.
Facilities for receiving and storing raw materials are fairly
consistent throughout the industry with few if any major
modifications associated with changes of raw materials.
Basically they consist of a receiving area where bulk carriers
can be attached to flexible lines or cans dumped into hoppers,
fixed lines and pumps for transfer of materials, and large
refrigerated tanks for storage. Wastes arise from leaks, spills
and removal of adhering materials during cleaning and sanitizing
of equipment. Under normal operations, and with good
housekeeping, receiving and storing raw materials is not a major
source of waste load*
It is in the area of processing raw materials into finished
products that the greatest variety is found, since processes and
equipment utilized are determined by raw material inputs and the
finished products manufactured. However, the initial operations
of clarification, separation and pasteurization are common to
most plants and products.
Clarification (removal of suspended matter) and separation
(removal of cream, or for whole milk standardization to 3.556
butterfat content) generally are accomplished by using large
Centrifuges of special design. In some older installations
clarification and separation are carried out in separate units
that must be disassembled for cleaning and sanitizing, and for
sludge removal in the case of clarification. In most plants
clarification and separation are accomplished by a single unit
that automatically discharges the sludge and can be cleaned and
sanitized without disassembly (cleaned in place or CIP).
Following clarification and separation, those materials to be
subjected to further processing within the plant are pasteurized.
Pasteurization is accomplished in a few older plants by heating
the material for a fairly long period of time in a vat (vat
pasteurization). In most plants pasteurization is accomplished
by passing the material through a unit where it is first rapidly
heated and then rapidly cooled by contact with heated and cooled
plates or tubes (high temperature short time or HTST
pasteurization).
20
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After the initial operations mentioned above, the processes and
equipment employed become highly dependent on product. Examples
of equipment encountered are; tanks and vats for mixing
ingredients and culturing products, homogenizers (enclosed high-
pressure spray units), evaporators and various driers for removal
of water, churns and freezers. The processes employed for
manufacture of various products are indicated in Figure 1 through
11. The Finished products are then packaged, cased and sent to
storage for subsequent shipment.
The product fill lines employed in the dairy products industry
are typical liquids and solids packing units, much like those
employed in many industries, with only minor modifications to
adapt them to the products and containers of the industry.
Storage is in refrigerated rooms with a range of temperaturs from
below zero to above freezing.
The product manfacture and packaging areas of a plant are the
major sources of wastes. These wastes result from spills and
leaks, wasting of by-products (e.g., whey from cheese making),
purging of lines during product change in such as freezers and
fillers, product washing (e.g., curd washing for cheese) and
removal of adhering materials during cleaning and sanitizing of
equipment. Wastes from storage and shipping result from rupture
of containers due to mishandling and should be minimal.
It should be noted that most plants are multi-product facilities,
and thus the process chain for a product may differ from the
single product chain indicated in Figures 1 through 11.
Frequently in multi-product plants a single unit such as a
pasteurizer may be utilized for processing more than one product.
This represents considerable savings in capital outlay as process
equipment, being of special design and constructed of stainless
steel, is quite expensive.
21
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FIGURE 1
Basic Process
RECEIVING STATION
(Alternate
Recycling)
1 *•
1
^tf -— rf FrV— \
1
L
1 —
-*"© 1
1 . Receiving
1
u -/£T
i ^
r .^ ^7
2, Cooling
1
•
3. Storage Tanks
,
4. Shipping
1
[^. tfw
1
1
1
1
J
"n -r
r
-------
FIGURE 2
KLl'lD Mll.K
Basic i'rocess
CS - Cleaning and Sanitizing Solutions
WW - Wash Water (cold or hot)
CW - Cooling Water
ST - Steam
EF - Effluent to drain
23
-------
FIGURE 3
CULTURED PRODUCTS
Bagi&J'roceas
1
1
I
1. Receiving
2. Storage
1
x-x 1
l_
,„ 0
1 ^-N.
_|
"1- 0
3. Separation
t
' *
1
1
1
4. Hllk
1
Cream '
"^ Storage f~^
1 '
eurizatian
'
1 . Culturing
1
Recycling |
[7^ !
i
8. Cooling
1
•~-Q-\
•
9. Packaging
WW - Wash Water (cold or hot)
CM • Cooling Mater
ST - Steam
'
10. Shipping
5, Cream /~^
/*-*•
^ ( WW
H* ( cw
M f ST
24
-------
FIGURE 4
BUTTER
By-Pi-oducts
Basic Process
CS - Cleaning and SanltUlng Solution
WW - Wash Water (cold or hot)
CW - Cooling Water
ST - Steam
EF - Effluent to drain
14. Cold
Storage
15. Shipping
25
-------
FIGURE 5
UATURAL ASP PROCESSED CHEESE
By-Product a
Baaic Proceit
I. Receiving
EF
Excess
Cream
2. Storage Tanks
3. Clarification/
Separation
r
Alternate
Recycling '
u—fc^
. P«steurication
Sweet Whey
. Cheese
Manufacture
6. Pressing In
Hoopj
7. Drying
8. Curing
9. Process Chees*
Preparation
10. Blending
11. Pastaurltatlor
and Cooling
L2. Packaging
.J
L3. Cold Storage
Laaand
CS • CLt«iung end SaniClclng Solution
WW • Waah W«t»r ( cold or hot)
CW • Cooling W«tar
ST • St««m
EF - Efflutnt to drain
14. Shipping
-------
FIGURE 6
COTTAGE CHEESE
By-Products
Basic Process,
1. Receiving
2. Storage
1 '
' 1
3. Separating
4. Pasteurization
n
5. Cottage Cheese
Manufacture
6. Cheese
Dressing
7. Packaging
| '
! 1
8, Storage
CW)
fcs]
Lege nd
9. Shipping
CS - Cieaning and Sanitizing Solution
WW - Wash Water (cold or hot)
CW - Cooling Water
ST - Steam
EF - Effluent to drain
-------
no
CD
i I
.J L.
I
1) (t
I— 1
L , I
H
o
c:
-------
FIGURE 8
Shipping
CS ricanln? «nd ban)tiling Solution
WW - 'ash Water (cold o^ hot)
CW - .-ulinn Water i
ST - St.-am
EF - Elflutsnt to drain
29
-------
FIGURE 9
DRY MILK
Basle Process
I,onen<
Cs " Cleaning and Sjnitizin£>
WW - Wash Water icoLd or hot)
CW ~ Cooli nn Water
EF - Effluent to drain
30
-------
FIGURE 10
CONDENSED WHEY
Basic Process
r
L
t- — ©
L. Receiving
L
h — ©
|
~L — ^^
2. Storage
r
Alternate
Recycling
r~ *•
1
1
Condensate
1 *"
i -g) 1
L
'
w
U (ww
_ i
3. Pasteurization
1
4. Condensing
i
5 . Cooling and
Storage
1
6, Packaging
'
7. Storage
1
8. Shipping
n
. j
Legend
CS - Cleaning
WW • Wash Wate
CW - Cooling H
ST - Steam
EF - Effluent
-------
FIGURE 11
r
* ©
t
i
i —
i
H«£X£J-i2fi_ 1
l__/£j\— _]
1 '~ *"
i — (sr) 1
1
1,
•« /^"h
L
DRY WHEY
Basic Process
i
1. Storage
1
3. Pasteurization
• •
4. Condensing
'
i •
1
7. Final Drying
1 •
8. Packaging
1
1
9, Storage
'
10, Shipping
L fc?\
U (CSJ
c\
,
L« (cs)
« (C^i
.- ^wwj
1 ^-^
~I
r* (ww)
. ,.._,)
1
..y""^
1^
• /wih
^J
J
Legend
CS - Cleaning and
WW • Wash Water (c
ST - Steam
EF - Effluent to d
32
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SECTION IV
INDUSTRY CATEGORIZATION
Introduction
In developing the effluent limitations guidelines and standards
of performance, a judgement must be made as to whether the dairy
products industry should be treated as a single entity or divided
into subcategories for the application of these guidelines and
standards. The most cursory examination, especially if augmented
by even minimal data, indicates the inadvisability of attempting
to apply a single set of guidelines and standards to segments of
an industry displaying such wide variation in raw material input,
processes employed, end products manufactured, and levels of
waste generation. The problem then becomes one of developing a
logical subcategorization that will facilitate orderly
development of effluent limitations and standards, taking into
account the affect of factors such as raw materials input,
processes employed, finished products manufactured, wastes
discharged, age and size of plants, and other factors.
Raw Materials Input
Raw materials for dairy products processing typically consist of
milk and milk products (cream, condensed or dried milk and whey,
etc.). Non-dairy ingredients (sugar, fruits, flavors, nuts, and
fruit juices) are utilized in certain manufactured products such
as ice cream, flavored milk, frozen desserts, yogurt, and others.
A raw material may be involved in manufacture of a number of
finished products; for example, cream may serve as a raw material
for such varied finished products as fluid milk and cream,
butter, ice cream, and cultured products. Moreover, considerable
variation is encountered in the raw materials employed in
manufacture of a single product such as ice cream. Hence, raw
materials input is poorly adapted to use as a single criterion
for subcategorization, as it would require a separate subcategory
for most individual plants.
Processes Employed
The processes employed in the dairy products industry can be
divided into two groups, those essentially common to the entire
industry such as receiving, storage, transfer, separation,
pasteurization and packaging, and these employed in more limited
segments of the industry such as churning, flavoring, culturing,
and freezing.
In attempting to base subcategorization primarily or solely on
processes employed several problems are encountered. The
physical setup of dairy products plants is seldom if ever such
that it is possible to isolate the waste discharge from a single
process and thus generate the data base necessary for development
33
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of valid effluent limitations and standards applicable to
processes. In addition, subcategorization based on process alone
fails to account for the differences in potential waste
generation that result from application of a common process
(e.g., pasteurization) to a variety of materials such as milk,
cream, ice cream mix, and whey.
Wastes Discharged
Pollutants contained in the wastes discharged by dairy products
plants represent materials lost through direct processing of raw
materials into finished products and materials lost from
ancillary operations. The former group consists of milk, milk
products and non-dairy ingredients (sugar, fruits, nuts, etc.),
while the latter consist of cleaners and sanitizers used in
cleaning equipment, lubricants (primarily soap and silicone-
based) used in certain handling equipments, and sanitary and
domestic sewage from toilets, washrooms and kitchens.
These wastes with the possible minor exceptions of some
lubricants, cleaners, sanitizers, and concentrated wheys
(especially acid wheys from production of cottage cheese), are
readily degradable in typical biological treatment systems. Any
refractive materials that are represented are generally present
in such low concentrations as to pose no taste and odor problems.
Since there are no clear cut differences (other than their
concentrations) in wastes discharged by dairy products plants,
subcategorization based on wastes dicharged would be arbitrary
and questionable.
Finished Products Manufactured
The finished products manufactured in dairy products plants are
the results of application of specific sets of processes to
selected groups of raw materials; hence, waste discharges
associated with production of specific finished products reflect
all variations attributable to raw materials, direct production
processes, and associated ancillary operations. Therefore, a
subcategorization based on finished products has been adopted.
The subcategories proposed and their associated finished products
are given in Table 7. Multiple-product plants should be treated
as weighted composites of the subcategories.
One would expect age and size of plant, modifications of process
and other miscellaneous factors to affect the raw waste loads
generated by plants, especially for those manufacturing the same
finished products, but in general, no such correlation is borne
out by the data compiled during the course of this study. In
fact, tests in several of the newer, highly-automated plants of
large size yielded higher than average waste loads for their
subcategories. Apparently any minor variations attributable to
age and size of plant, raw materials in£ut and process
34
-------
modifications are overshadowed by variations caused by "quality
of management" (housekeeping, maintenance, personnel attitudes,
etc.)- Refinement of guidelines on a technology basis for size
and age must await greater standardization of intangibles such as
management, which should result from implementation of
guidelines.
The exceptions to the foregoing that were noted and documented
fall within the subcategories of receiving stations and natural
cheese plants, the least complex operations in the industry and
ones in which variation of intangibles is minimal. Here the data
indicates a consistent difference in the waste loads generated by
stations receiving milk in cans versus those receiving milk in
bulk and large versus small cheese plants. Since these
exceptions are accommodated within the segmentation of the
subcategories by plant size that is based on economic
considerations (i.e., receiving stations that receive appreciable
portions of milk in cans and the affected natural cheese plants
all fall within the small size designation), they have not
resulted in further modification of the categorization or
guidelines.
With the two minor exceptions noted in the preceeding paragraph,
there is no justification for further segmentation of the dairy
industry on the basis of the degree of effluent reduction that is
technically feasible. However, when the economic impact of the
guidelines (determined in a collateral economic study conducted
by Development Planning and Research Associates, Inc.) is
utilized as a basis for judgment, the converse is true and a need
for further segmentation of the subcategories by plant size is
indicated. The DPRA study concludes that costs imposed on small
plants by implementation of a uniform level of control technology
across the industry (e.g., equivalency of activated sludge as
end-of-pipe treatment for all point sources) would result in
closure of"about 573 small plants. This severe impact on small
plants is the result of both lower profitability of small
operations, many of which are of questionable long-term viability
even without imposition of high waste treatment costs, and their
higher per unit of production waste control costs attributable to
the economics of size in waste treatment. To lessen the economic
impact of the , guidelines a small plant segment has been
designated in each subcategory; and for these segments less
stringent effluent limitations based on the pollutant reduction
attainable utilizing treatment technology with much lower
associated costs are recommended. The upper input limitations
for designation as a small plant that are recommended by
economists are shown in Table 8.
Conclusion i
On the basis of the preceeding discussion it can be concluded
that, for the purpose of establishing effluent limitations
guidelines and standards of performance for new sources, the
35
-------
dairy industry can logically be sufccategorized on
the type of products manufactured.
the basis of
Subcategorization can be meaningful only to the extent that a
valid basis (such as quantitive data, clearly identifiable
technical, considerations, or economic considerations) exist for
developing a sound guideline or standard for each category
defined. On the basis of existing data and knowledge it is
suggested that the dairy industry be subcategorized as indicated
in Table 7, and that the subcategories be further segmented by
size as indicated in Table 8.
The typical manufacturing processes for the products that
characterize the proposed subcategories are illustrated in
Figures 1 through 11.
The proposed subcategories represent single-product plants.
Because of the large number of product combinations manufactured
by individual plants in the industry and their varying
proportions in relation to total plant production, further
subcategorization for multi-product plants is impractical.
Rather, it is proposed that guidelines and standards for multi-
product plants be the summation of weighted averages of the
guidelines for the corresponding single product processes
(plants), using the total BOD input for each manufacturing
subcategory representation as the weighing factor to which the
appropriate limitation value is applied.
36
-------
TABLE 7
Proposed Subcateqorization for the Dairy Products Industry.
Name of Subcategory
Products Included
Receiving Station
Fluid Products
Cultured Products
Butter
Natural and Processed Cheese
Cottage cheese
Ice cream. Frozen Desserts,
Novelties and other Dairy
Desserts
Ice Cream Mix
Condensed Milk
Dry Milk
Condensed Whey
Dry Whey
Raw Milk
Market milk (ranging from 3.5%
to fat-free), flavored milk
(chocolate and other) and cream
(of various fat concentrations,
plain and whipped).
Cultured skim milk ("cultured
buttermilk") yoghurt, sour cream
and dips of various types.
Churned and continuous*process
butter.
All types of cheese
foods except cottage cheese
and cultured cream cheese.
Cottage cheese and cultured
cream cheese
Ice cream, ice milk, sherbert,
water ices, stick confections,
frozen novelty products, frozen
mellorine, puddings, other
dairy-based desserts.
Fluid mix for ice cream and other
frozen products.
Condensed whole milk, condensed
skim milk, sweetened condensed
milk and condensed buttermilk.
Dry whole milk, dry skim milk, and
dry buttermilk.
Condensed sweet whey and condensed
acid whey.
Dry sweet whey and dry acid whey.
37
-------
Table 8
Upper Input Limitations
For Designation As A small Plant
Subgategory
Receiving Stations
Fluid Products
Cultured Products
Butter
Cottage cheese and
Cultured Cream cheese
Natural and
Processed Cheese
Fluid Mix for Ice
Cream S Other
Frozen Desserts
Ice Cream and
Frozen Desserts
Condensed Milk
Dry Milk
Condensed Milk
Dry Whey
Units^of^Input
150,000 Ib/day M.E.
250,000 Ib/day M.E.
60,000 Ib/day M.E.
150,000 Ib/day M.E.
(40,000 Ib 40X Cream)
25,000 Ib/day M.E.
100,000 Ib/day M.E.
Dairy Products Input
of 85,000 Ib/day M.E.
Dairy Products Input
of 85,000 Ib/day M.E.
100,000 Ib/day M.E.
145,000 Ib/day M.E.
300,000 Ib/day Fluid
Raw Whey (20,700 Ib/day
of Solids)
57,000 Ib/day 40*
Solids Whey (22,800
Ib/day of Solids)
Corresponding
BODS Input
15,600 Ib/day
25,900 Ib/day
6,200 Ib/day*
18,800 Ib/day
2,600 Ib/day
10,390 Ib/day
8,830 Ib/day*
8,830 Ib/day*
10,390 Ib/day
15,070 Ib/day
14,160 Ib/day
15,620 Ib/day
*BOD5_ of dairy products only; does not include BOD5
of sugar, fruits, nuts and other non-dairy ingredients.
38
-------
SECTION V
WASTE CHARACTERIZATION
Sources of Waste
The main sources of waste in dairy plants are the following:
1. The washing and cleaning out of product remaining in
tank trucks, cans, piping, tanks, and other equipment
performed routinely after every processing cycle.
2. Spillage produced by leaks, overflow, freezing-on,
boiling-over, equipment malfunction, or careless
handling.
3. Processing losses, including:
(a) Sludge discharges from GIF clarifiers;
(b) Product wasted during HTST pasteurizer start-up,
shut-down, and product change-over;
(c) Evaporator entrainment;
(d) Discharges from bottle and case washers;
(e) Splashing and container breakage in automatic
packaging equipment, and;
(f) Product change-over in filling machines.
4. Wastage of spoiled products, returned products, or by-
products such as whey.
5. Detergents and other compounds used in the washing and
sanitizing solutions that are discharged as waste.
6. Entrainment of lubricants from conveyors, stackers and
other equipment in the waste water from cleaning
operations.
7. Routine operation of toilets, washrooms, and restaurant
facilities at the plant.
8. Waste constituents that may be contained in the raw
water which ultimately goes to waste.
The first five sources listed relate to the product handled and
contribute the greatest amount of waste.
Nature of Dairy. Plant Wastes
Materials Wasted
Materials that are discharged to the waste streams in practically
all dairy plants include:
39
-------
1. Milk and milk products received as raw materials.
2. Milk products handled in the process and end products
manufactured.
3. Lubricants (primarily soap and silicone based) used
in certain handling equipment.
4. Sanitary and domestic sewage from toilets, washrooms
and kitchens.
Other products that may be wasted include:
1. Non-dairy ingredients (such as sugar, fruits, flavors,
nuts, and fruit juices) utilized in certain manufactured
products (including ice cream, flavored milk, frozen
desserts, yoghurt, and others).
2. Milk by-products that are deliberately wasted,
significantly whey, and sometimes, buttermilk.
3. Returned products that are wasted.
Uncontaminated water from coolers and refrigeration systems,
which does not come in contact with the product, is not
considered process waste water. Such water is recycled in many
plants. If wasted, it increases the volume of the effluent and
has an effect on the size of the piping and treatment system
needed for disposal. Roof drainage will have the same effect
unless discharged through separate drains.
Sanitary sewage from plant employees and domestic sewage from
washrooms and kitchens is usually disposed of separately from the
process wastes and represents a very minor part of the load-
The effect on the waste load of the raw water used by the plant
has often been overlooked. Raw water can be drawn from wells or
a municipal system and may be contributing substantially to the
waste load arising from cooling water and barometric condensers
unless periodic control of its quality indicates otherwise.
Composition of Wastes
The principle organic constituents in the milk products are the
natural milk solids, namely fat, lactose and protein. Sugar is
added in significant quantities to ice cream and has an important
effect in the waste loads of plants producing that product. The
average composition of selected milk, milk products and other
selected materials is shown in Table 9.
Cleaning products used in dairy plants include alkalis (caustic
soda, soda ash) and acids (muriatic, sulfuric, phosphoric,
acetic, and others) in combination with surfactants, phosphates,
and calcium sequestering compounds. BOD5 is contributed by acids
and surfactants in the cleaning product. However, the amounts of
cleaning products used are relatively small and highly diluted.
40
-------
Table 9
Composition of Common
Dairy Products Processing Materials
Material
Almonds (dried)
Blackberries (canned. Light syrup)
Buttermilk
Flu1d(cultured skim milk)
Dri ad
Chocolate (semi-sweet)
Cheese
Brick
Cheddar
Cottage (uncreamed)
Cherries (sweet, Light syrup)
Cocoa (dry powder, Low-med fat)
Cream (fluid)
Half er.d Half
Light (coffee or table)
Light whipping
Heavy whioping
403
Kilk (fluid)
Whole,' 3.7% Fat
Whole, 3.5% Fat
Ski in
f-'ilk (canned)
Evaporated (unsweetened)
Condensed (sweetened)
Milk (dried)
Whole
Skim
Orange Juice
All cc-rasrcfal varieties
Peaches, canned
Water pack
Juice pack
Pecans
Strawberries
Canned, water pack
Frozen, sweetened
Sugar
Walnuts, Black
Whey
Fluid
Dried
40% SolIds
% Protein
18.6
0.8
3.6
- 34.6
4.2
22.2
25.0
17.0
0.9
19.2
3.2
3.0
2.5
2.2
2.1
3.5
3.5
3.6
7.0
8.1
26.4
35.9
0.7
0.4
0.6
9.2
0.4
0.4
0.0
20.5
0.9
12,9
5.3
% Fat
54.2
0.6
0.1
5.3
35.7
30.5
32.2
0.3
0.2
12.7
11.7
20.6
31.3
37.6
40.0
3.7
3.5
0.1
7.9
8.7
27.5
' 0.8
0.2
0.1
0
71
0.1
0.2
0.0
59.3
% Carbohydrate
19.5
17.3
5.1
50.0
57.0
1,9
2.1
2.7
16.5
53.8
4.6
4.3
3.6
3.1
2.9
4.9
4.9
5.1
9.7
54.3
3B.2
52.3
10.4
0.3
1.1
0.5
11
14
23,
99.
14,
5,
73.
30.1
BOD5_ Kg/100Kg (lb/100 Ib)
80.89
13.30
7.22
74.63
65.49
51.35
55.89
19.66
12.51
68.17
16.89
24.39
32.93
37.87
39.77
10.39
10.23
7.44
21.74
53.76
78.85
75.01
7.85
6.11
8.75
83.17
4.40
17.06
68.75-
85.15
4.72
65.07
26.71
-------
Sanitizers utilized in dairy facilities include chlorine
compounds, iodine compounds, quaternary ammonium compounds, and
in some cases acids. Their significance in relation to dairy
wastes has not been fully evaluated, but it is believed that
their contribution to the BOD5 load is quite small.
Most lubricants used in the dairy industry are soaps or
silicones. They are employed principally in casers, stackers and
conveyors. Soap lubricants contribute to BQD5 and are more
widely used than silicone based lubricants.
The organic substances in dairy waste waters are contributed
primarily by the milk and milk products wasted, and to a much
lesser degree, by cleaning products, sanitizing compounds,
lubricants, and domestic sewage that are discharged to the waste
stream. The importance of each source of organic matter in dairy
waste waters is illustrated in Table 10.
Table 10
Estimated Contribution of Wasted Materials to the BOD5
Load of Dairy Waste Water. (Fluid Milk Plant) . """
kg BOD5/kkg
(lb/1000 Ib)
Milk Eqivalent
Processed
Milk, milk products, and
other edible materials
Cleaning products
Sanitizers
Lubricants
Employee wastes (Sani-
tary and domestic)
3.0
0.1
Undetermined, but
probably very small
Undetermined, but
probably small
Percent
94%
3
100$
The inorganic constituents of dairy waste waters have been given
much less attention as sources of pollution than the organic
wastes simply because the products manufactured are edible
materials which do not contain hazardous quantities of inorganic
substances. However, the nonedifcle materials used in the
process, do contain inorganic substances which by themselves, or
added to those of milk products and raw water, potentially pose a
pollution problem. Such inorganic constituents include
42
-------
phosphates (used as deflocculants and emulsifiers in cleaning
compounds), chlorine (used in detergents and sanitizing products)
and nitrogen (contained in wetting agents and sanitizers).
Variability of Dairy Wastes
A significant characteristic of the waste streams of practically
all dairy plants is the marked fluctuations in flow, strength,
temperature and other characteristics. Wide variations of such
parameters frequently occur within minutes during the day,
depending on the processing and cleaning operations that are
taking place in the plant. Furthermore, there are usually
substantial daily and seasonal fluctuations depending on the
types of products manufactured, production schedules, maintenance
operations, and other factors. Typical hourly variations in
flow, BOD5 and COD of a plant manufacturing cottage cheese is
illustrated in Figure 12. Figure 13 illustrates daily variations
in BOD5 strength of the waste from the frozen products drain of
another dairy plant.
It is important to recognize the highly variable nature of the
wastes when a sampling program is undertaken in a dairy plant.
Unless the daily samples are a composite of subsamples taken at
frequent intervals and proportioned in accordance with flow,
results could depart considerably from the true average values.
Furthermore, the sampling period should ideally cover enough days
at various times of the year to reduce the effect of the daily
and seasonal variations.
Wjjste Loa(3 Units
Waste loads have frequently been reported in terms of
concentration or "strength" of a given parameter in the waste
stream, such as parts per million (ppm) or milligrams per liter
(mg/1). Although a unit of concentration can be significant as a
loading factor for waste treatment systems and for water quality
analysis, it is not meaningful for control purposes because any
amount of water added to the waste stream will result in a lower
concentration, while the volume of polluting material discharged
remains unchanged. For pollution control purposes, the total
weight of pollutant discharged in a unit of time is a more
meaningful factor.
Researchers have long recognized a direct relationship in the
dairy industry between the total weight of pollutant discharged
and the weight or volume of material processed. Waste loads of
different plants can be meaningfully compared on the basis of a
unit load, such as kg (Ib) of a given waste parameter per kkg
(1000 Ib) of raw material or product.
Up until this time, it has been the accepted practice to
characterize the raw wastes of dairy plants in relation to the
number of pounds of milk or "milk equivalent" received or
proce ssed. During this study it was found that the "miIk
43
-------
FIGURE 12
2 -
12 2 4
MIDNIGHT
8
10 12 2
NOON
TIME
10
Hourly variations in ppm BOD5, COD and waste water
fora dairy plant
44
-------
FIGURE 13
15000
10000
o
O
5000
1
!
,
\
h
i
\\
, 1
!
%
i,
5 §
S
s n ^
j g ,
i
T W TH F M
TH F M T TH
M
Variation in waste strength of frozen products drain for consecutive sampling
days in one month.
W TH
-------
equivalent" concept has been defined differently by various
sources, has often been applied inconsistently, and has at least
been confusing to many people that have used waste load data for
research, management, or control purposes.
Some of the inconsistencies between definitions or applications
of the milk equivalent concept are a result of arbitrary
decisions that must be made in its definition, including the
following:
1. The milk equivalent of a milk product can be referred
either to raw milk as received from the farms, or to
"whole milk" as standardized for sale in the market.
2. Raw milk varies in composition, and therefore a
conventional solids content must be agreed upon if the
definition is to be consistent.
3. The milk equivalent can be defined in terms of the fat
solids the non fat solids or the total solids of the
whole milk and of the product in question.
U. Milk products to which other than milk solids have been
added (such as ice cream or sweetened condensed milk)
further complicate the definition of a milk equivalent
based on total solids as opposed to fat or non fat milk
solids.
Because of this situation, it is proposed that the unit waste
loads defining the effluent limitation guidelines (significantly
BOD) be expressed in terms of the total BOD5 input contained in
the dairy and other raw materials utilized in the production
processes. This approach has the following advantages:
1. The many arbitrary decisions involved in establishing a
definition of the "milk equivalent" concept are
eliminated.
2. The BOD5 content (in Ib BOD5 per Ib of raw material) of
any given daily raw material can be determined by
standard laboratory analysis. Values for most of the
typical dairy and other raw materials have been
published and are reasonably consistent.
Accordingly, the waste load data presented in the report have
been expressed in or converted to units relating to the quantity
of BOD5 in the raw materials received or processed.
To maintain consistency in the application the waste load data
and guidelines set forth in this report it is essential that the
procedures set forth in this report be adopted as standards to
calculate the waste load of any particular plant. For
simplicity, only the process raw materials are considered in the
computations; it must be remembered, however, that BOD5 can also
46
-------
be contributed by lubricants, detergents, sanitizers, and in
some cases, sanitary sewage. However, the contribution from
these latter materials should be of such low magnitude as to be
of no consequence in relation to the load borne in a treated
final effluent, particularly when the precision of sampling and
analytical methods are considered.
BOD
Available data indicates that the daily average BOD5 strength of
dairy plant wastes varies over a broad range, from as low as 40
mg/1 to higher than 10,000 mg/1, with the great majority of
plants falling within 1,000 to 4,000 mg/1. A summary of
available raw waste BOD5 data appears in Table 11.
waste discharge per
reasons
In expressing BOD5 loss per BOD5 received (processed) it is
convenient and useful to express the unit load as kg (Ib) BODI3 of
waste discharae oer 100 kg (Ib) received processed for two
1. kg BOD5/100 kg (lb/100 Ib) can be read directly as per
cent BOD5 loss, i.e., for ice cream plants the mean loss
is 14.8 kg/100 kg (14.8 lb/100 Ib) or directly, 14.8
percent.
2. kg BOD5/100 kg BOD5 (Ib BOD5/100 Ib BOD) is
approximately equal to kg BOD5/1000 milk equivalent when
the raw material is whole milk, since the BOD5 of whole
milk is approximately 10 percent by weight. "~
Mean unit BOD5 loads for plants range from 0.41 kg/100 kg BODS or
0.41 kg/1000 kg M.E., (0.41 lb/100 Ib BOD5 or 0.41 Ib pr 1000~ Ib
M.E.) for receiving stations to 16.8~ kg/100 kg BOD5 or 14.6
kg/1000 kg M.E. (16.8 lb/100 Ib BOD5 or 14.6 lb/1000 Ib M.E.) for
cottage cheese plants. In general, the relative magnitudes of
the mean unit BOD5 loads for the various subcategories are as
would be expected when considering the viscosity and BOD5 content
of the product and the nature of the processes.
cop
Chemical Oxygen Demand (COD) is the amount of equivalent oxygen
required for oxidation of the organic solids in an effluent,
measured by using chemical oxidizing agents under certain
specified conditions instead of using microorganisms as in the
BOD test. It can be used alternatively to BOD5 as a measure of
the strength of the waste water. The advantages of the COD test
over the BOD5 is that it can be completed in a relatively short
time and there is generally a lesser chance for error in
performing the test.
There is disagreement, however, on the accuracy and relative
merits of each test in determining the oxygen demand of a dairy
effluent. In spite of being more cumbersom, and inherently
47
-------
TABLE 11
Summary of Calculated, Literature Reported and Identified Plant
Raw Waste BODS Data
-P*
00
Type of Plant
A. Single Product
Receiving Station (CansJ
Receiving Station (Bulk)
Fluid Products
Cultured Products
Butter
Cottage Cheese
Natural Cheese
Ice Cream
Ice Cream Mix
Condensed Milk
Dry Milk
Condensed Whey
Dry Whey
B. Multi-Products
Literature
Calculated kg BOD 5 Number
per 1,000 kg Milk/jj of Plants
Equivalent Received^ Reporting
0
0
0
1
1
0.47
0.33
.96-1.32
1.11
8.69
1.77
1.81
.67-1.26
.94-1.91
.22-1.3i
.12-1.85
2.14
-
1.66
1.40
_
-
-
2.17
1.79
1.11
-
-
-
_
1.59
1.32
-
2.11
1.30
1.46
-
-
3.49
-
-
7
1
16
11
5
21
7
5
9
3
3
10
8
1
10
9
1
6
19
1
Reported Plant Sources
Kg B005
per 1,000 kg Milk
Equivalent Received
Ranee Mean
0
0
0
1
0
1
0
0
0
3
0
0
0
0
1
0
.02-1.13
-
.14-17.06
.19-1.91
.30-42.00
. 30-4 . 04
.90-21.04
.18-13.30
.40-13.50
.27-0.31
.40-57.20
.66-7.87
.30-3.26
-
.90-12.90
.07-2.22
-
.30-320
.30-3.88
_
-
0.28
0.10
3.60
0.86
14.64
2.00
5.54
3.67
6.06
0.29
22.33
2.90
1.21
2.14
6.79
0.81
2.46
2.54
1.32
2.21
3.00
Number
of Plants
Ren or t inE
5
1
6
1
-
•5
10
1
2
3
7
5
5
5
-
_
1
1
4
1
1
3
1
1
4
1
1
1
1
3
1
3
Identified Plant Sources
Kg BOD5
per 1,000 kg Milk
Equivalent^ Received
Ranee Mean
0
0
0
0
0
0
0
0
2
0
0
2
0
1
1
.30-0.70
-
.30-7.16
_
-
.24-0.93
.68-19.60
0.63
.41-4.00
.41-2.44
.24-0.88
.02-1.16
.26-6.94
.35-7.84
-
_
_
-
.95-10.10
-
-
.09-4.78
-
_
.39-1.14
-
-
-
_
-
.28-20.10
-
. 06-4 . 20
0.46
0.17
3.21
0.80
-
0.54
6.75
0.63
2.20
1.18
0.43
0.60
4.54
3.0U
-
_
1.80
7.21
3.80
6.24
2.21
3.44
1.70
0.93
0.68
0.85
5.41
3.61
0.28
6.43
8.62
2.15
2.12
Kg BOD5
per 100 kg
BODs Received
Ranee
0.30-0.70
-
0.30-7.16
_
-
0.35-9.33
1.33-40.50
-
0.41-4.00
0.60-3.52
0.58-2.19
0.05-2.88
2.26-6.94
0.80-7.84
-
_
_
0.95-10.10
-
-
2.80-4.78
-
_
0.39-1.24
_
-
-
_
.
1.28-20.10
-
1.10-4.20
Mean
0.46
0.17
3.21
0.80
_
0.60
13.45
0.99
2.20
1.62
1.05
1.44
4.54
3.10
_
_
1.80
16.70
3.80
6.24
2.21
3.72
1.70
0.98
0.83
1.04
8.29
3.61
0.31
6.43
s: 6 2
2.15
2.29
Fluid-Cottage
Fluid-Cultured
Fluid-Butter
Fluid-Natural Cheese
Fluid-Ice Cream Mix-Cottage-Cultured
Fluid-Ice Cream Mix-Cond.
Milk-Cultured
Fluid-Cultured-Juice
Fluid-Cottage-Cultured
Fluid-Cottage-Ice Cream
Fluid-Butter-Natural Cheese
Fluid-Cottage-Dry Milk
Fluid-Cottage-Cultured-Dry Whey (2>
Fluid-Cottage-Cultured-Ice Cream1 '
Fluid-Cottage-Cultured-Cond. Milk
Fluid-Cottage-Butter-Ice Cream-
Dry Mllk(2)
Butter-Dry Milk
Butter-Cond. Milk
Butter-Dry Milk-Dry Whey
Butter-Natural Cheese
Butter-Dry Milk-Ice Cream
Cottage-Cond. Milk
Cottage-Cultured-Dry Milk-Dry
Whey-Fluid
Cottage-Natural Cheese
Natural Cheese-Dry Whey
Natural Cheese-Cultured-Rec. Sta.
Natural Cheese-Cond. Whey
Notes: (1) Using SMP standard loads as developed in the "Study-of Wastes and Effluent Requirements of the Dairy Industry, Section III, July 1971."
(2) Excludes Whey dunping.
-------
providing a greater chance of error, the BOD5 test has been much
more widely used in the past. The results of the BOD5 test have
been regarded as more significant, because it was considered to
more nearly parallel what is actually taking place in natural
waters. Many dairy companies in the United States have
reportedly attempted to use the COD test but have discontinued
the practice because of the wide variation in BOD:COD ratios
measured.
More recently, the need for the COD test as a supplement the BOD5
test has been recognized, and many investigations consider it a
better method for assessing the strengths of dairy effluents.
A summary of BOD:COD data appears in Table 12. Significant
variations of the ratio are evident; the overall range of the
BOD:COD ratio for raw effluents reported from all sources is 0.07
to 1.03. The mean for identified plants is 0.57. This figure
can be used as a conversion factor.
Suspended Solids
The concentrations of suspended solids in raw dairy plant wastes
vary widely among the different dairy operations. The greatest
number of plants have suspended solids concentrations in the 400
mg/1 to 2000 mg/1 range.
The data on the suspended solids content of raw wastes of
identified plant sources are summarized in Table 13. The mean
suspended solids loads range from a low of 0.03 kg/100 kg BOD5
(0.03 kg/1,000 kg M.E.) for milk receiving stations to a high of
3.50 kg/100 kg BOD5 1.78 kg/kkg M.E.) for ice cream plants. Data
were not available for dry milk, cultured products, cottage
cheese, and can receiving stations operations as single product
categories. The suspended solids would be composed primarily of
coagulated milk, fine particles of cheese curd and pieces of
fruits and nuts from ice cream operations.
In all but two cases the suspended solids content of raw wastes
was lower than the BOD5 value. Further, there did seem to be a
significant correlation between the suspended solids content of
raw wastes and the type of plant operation. This fact is
supported by an analysis of suspended solids to BOD£ ratios for
identified plant source data. The values of the suspended solids
- BOD5 ratio were found to be distributed about a mean of 0.415
with a standard deviation of 0.32. This yields a coefficient of
variance of 77 percent. With 3 highest and lowest values
eliminated from the sample, the mean and standard deviation
become 0.368 and 0.155 respectively, giving a correlation of
variance of U2 percent. Further, a regression analysis of the
data the suspended solids and BOD5. data pairs resulted in the
following relationship with a correlation coefficient of 0.92.
Suspended solids = 0.529 BOD5 - 152.2.
49
-------
TABLE 12
of Literature Reported and Identified Plant Source
BOD5: COD Ratios for Raw Dairy Effluents
T: |»e of Plant
A. Single Product
Receiving Station (Cans)
Receiving Station (Bulk)
Fluid Products
Cultured Products
Butter
Cottage Cheese
Natural Cheese
Ice Cream
Ice Cream Hix
Condensed Hi Ik
Dry Milk
Condensed Whey
Dry Whey
B. Hulti-Products
Literature Reported Plant Sources
•iur;.ui.-r rtuu^: LUi) Katius
of Plants for Raw Effluent
Reporting
Identified Plant Sources
Range
Mean
0.66
0.31-0.66 0.45
Fluid-Cottage Cheese
Fluid-Cultured Products
Fluid-Butter
Fluid-Natural Cheese
Fluid-Ice Cream Mix-Cottage- Cultured
Fluid-Ice Credrn Mlx-Cond.
Milk-Cultured
Ul Fluid-Cultured-Juice
CD Fluid-Cottage-Cultured
Fluid-Cottage-Ice Cream
Fluid-Butter-Natural Cheese
Fluid-Cottage-Dry Milk
Fluid-Cottage-Cultured-Dry Whey
Fluid-Cottage-Cultured-Ice Cream
Fluid-Cottage-Cultured-Cond. Milk
Fluid-Cottage-Siitter-Ice Cream-
Dry Hi Ik
Bulter-Dry Milk
Butter-Cond. Milk
Butter-Dry Milk-Dry Whey
Butter-Natural- Cheese
Butter-Dry Milk-Ice Cream
Co'tage-Cond. Milk
Cottage-Cultured-Dry Milk-Dry
Uhey-Fli'id
Co' ia*-.*-N^iural Cht;.;se
Natural Chcose'^ry Uh«_.
Natural Chocse-CuIiurod-Rec, Sta.
Natural Cheepe-Con-J. Whey
C. Not Available
O.W-0.97 0.70
0.40-0.51 0.44
Number
of Plants
Reporting
BODc: COD Ratios
for Raw Effluent
Range Mean
0.55-0.59
0.50-0.79
0.63-0.72
0.49-0.56
0.55
0.57
0.53
0.57
0.66
1.03
0.67
0.50
0.07
0.60
0.51
0.53
0.11-0.80
-------
TABLE 13
Summary of Identi fled Plant Source
lype of Plant
A. Single Product
Receiving Station ( CansJ
Receiving Station (Bulk)
Fluid Products
Cultured Products
Butter
Cottage Cheese
Natural Cheese
Ice Cream
Ice Cream Mix
Condensed Milk
Dry Milk
Condensed Whey
Dry Whey
B. Multi-Products
Fluid-Cottage
Fluid-Cultured
Fluid-Butter
Fluid-Natural Cheese
Fluid-Ice Cream Mix-Cottage-Cultured
Fluid-Ice Cream Mix-Cond.
Milk-Cultured
Fluid-Cultured-Juice
Fluid-Cottage-Cultured
Fluid-Cottage-Ice Cream
Fluid-Butter-Natural Cheese
Fluid-Cottage-Dry Milk
Eluid-Cottage-Cultured-Dry Whey
Fluid-Cottage-Cultured-Ice Cream
Fluid-Cottage-Cultured-Cond. Milk
Fluid-Cottage-Butter-Ice Cream-
Dry Milk
Butter-Dry Milk
Butter-Cond. Milk
Butter-Dry Milk-Dry Whey
Butter-Natural Cheese
Butter-Dry Milk-Ice Cream
Cottage-Cond. Milk
Cottage-Cultured-Dry Milk-Dry
Whey-Fluid
Cottage-Natural Cheese
Natural Cheese-Dry Whey
Natural Cheese-Cultured-Rec. Sta.
Natural Cheese-Cond. Whey
Idem: if led Plant Sources
Kg Suspended Solids
Number per 1,000 kg Milk
of Plants Equivalent Received
Reporting ^ ^Rffngg
5
10
1
2
3
2
0.13-3.36
0.10-0.27
0.23-2.76
0.17-1.48
0.13-0.70
0.19-0.56
0.20-11.60
0.21-1.08
0.33-6.90
0.03
1.50
0.40
0.17
1.62
0-19
0.82
0.34
0.38
2.88
1.10
1.80
0.65
1.64
65
90
0.70
52
00
2.56
Suspended Solids
per 100 kg
BOD> Received
RanSe
1.36-3.36
0.14-0.27
0,46-5.86
0.17-1.48
0.33-1.74
0.47-1.40
0.46-11.6
0.21-1.08
0.44-7.16
Mean
0.03
1.50
0.40
0.19"
3,20
0.30
0.82
0.86
0.94
2.94
1.10
4.17
0.65
1.64
1.65
3.02
0.70
1.61
1.56
3.92
0.80-2.01
0.22-1.34
0.57
1.20
1.45
1.70
0.68
0.80-2.01
0.33-1.34
0.64
1.20
1.45
1.70
0.72
-------
This relationship between suspended solids and BOD5 seems to hold
over the range of BOD5 normally found in raw dairy plant wastes,
i.e., 1,000 mg/1 to 4,000 mg/1. Using the above equation and the
lower and upper limits of range of 1,000 mg/1, and 4000 mg/1,
suspended solids - BOD5 ratios of 0.38 and 0.49 respectively are
found.
Despite the relatively constant ratio of suspended solids to BOD5
of about .40 for the dairy industry as an aggregate, there is
some evidence that the ratio may be somewhat higher for cottage
cheese, ice cream, and drying operations where large amounts of
fines could potentially be wasted. Substantiation of this
hypothesis must await further data and analysis.
It should be noted that the amount of suspended solids in treated
effluent from dairy products processing is as much or more
dependent on the characteristics of the floe created in
biological treatment than on the suspended solids in the raw
waste. The former tends to have somewhat poor settling
characteristics.
EM
The pH of raw dairy wastes of a total of 33 identified plants
varies from 4.0 to 10.8 with an authentic mean of 7.8. The main
factor affecting the pH of dairy plant wastes is the types and
amount of cleaning and sanitizing compounds discharged to waste
at the plant. Commingling of waste streams tend to neutralize the
final discharge.
Temperature
Values reported by 12 identified plants for temperatures of raw
dairy wastes vary from 8° to 38°C (46°F to 100°F) with a mean of
24°C (76°F). In general the temperature of the waste water will
be affected primarily by the degree of hot water conservation,
the temperature of the cleaning solutions, the relative volume of
cleaning solution in the waste water. Higher temperatures can be
expected in plants with condensing operations, when the
condensate is wasted. Commingling and treatment tend to reduce
the higher temperature encountered.
Phosphorus
Phosphorus concentrations (as PO4) of dairy waste waters reported
by 29 identified plants range from 9 mg/1 to 210 mg/1, with a
mean of 48 mg/1.
Part of the phosphorus contained in dairy waste water comes from
the milk or milk products that are wasted. Waste water
containing *\% milk would contain about 12 mg/1 of phosphorus (3) .
The bulk of the phosphorus, however, is contributed by the wasted
detergents, which typically contain significant amounts of
phosphorus. The wide range of concentrations reported reflect
-------
varying practices in detergent usage and
solutions.
Nitrogen
recycling of cleaning
Ammonia nitrogen in the waste water of 9 identified plants varied
between 1.0 mg/1 and 13.4 mg/1, with a mean of 5.5 mg/1. Total
nitrogen in 10 plants ranged from 1.0 wg/1 to 115 mg/1, with a
mean of 64 mg/1.
Milk alone would contribute about 55 mg/1 of nitrogen at a 1%
(10,000 mg/1) concentration in the waste water. Quaternary
ammonium compounds used for sanitizing and certain detergents can
be another source of nitrogen in the waste water.
Chloride
six identified plants reported chloride concentrations ranging
from 46 mg/1 to 1,930 mg/1; the mean was 483 mg/1. The principal
sources of chloride in the waste stream may include brine used in
refrigerator systems and chlorine based sanitizers. Milk and
milk products are responsible for part of the load; at a 156
concentration in the waste water, milk would contribute 10 mg/1
of chloride.
Waste Water Volume
Waste water volume data are shown in Tables 14 (in metric units)
and 14A (in English units). Waste water volumes consistent with
good in-plant practices are shown in Table 14B.
Waste water flow for identified plants covers a very broad range
from a mean of 542 1/kkg milk equivalent (65 gal per 1,000 Ib,
M.E.) for receiving stations to a mean of over 9,000 1/kkg milk
equivalent (over 1,000 gal pr 1,000 Ib M.E,) for certain
multiproduct plants. It should be noted that waste water flow
does not necessarily represent total water consumed, because many
plants recycle condenser and cooling water and/or use water as a
necessary ingredient in the product.
Principal Factors Determining Dairy Waste Loads
Prior research has shown that a major controlling factor of the
raw waste loads of dairy plants is the degree of knowledge,
attitude, and effort displayed by management towards implementing
waste control measures in the plant. This conclusion was
reaffirmed by the investigations carried out in this study.
Good waste management is manifested in such things an adequate
training of employees, well defined job description, close plant
supervision, good housekeeping, proper maintenance, careful
production scheduling, finding suitable uses or disposal methods
for whey and returned products other than discharge to drain,
salvaging products that can be reused in the process or sold as
53
-------
TABLE U
Stmary of Literature Reported and Identified Plant Source
Raw Waste Hater Volume Data
Typ e _p_f_
A. Single Product
Receiving Station (CansJ
Receiving Station (Bulk)
Fluid products
Cultured Products
Butter -
Cottage Cheese
Natural Cheese
Ice Cream
Ice Cream Mix
Condensed Milk
Dry Milk
Condensed Whey
Dry Whey
B. Multi-Products
Fluid-Cottage
Fluid-Cultured
Fluid-Butter
Fluid-Natural Cheese
Fluid-Ice Cream Mix-Cottage-Cultured
Fluid-Ice Cream Mix-Cond.
Milk-Cultured
Fluid-Cultured-Juice
Fluid-Cottage-Cultured
Fluid-Cottage-Ice Cream
Fluid-Butter-Natural Cheese
Fluid-Cottage-Dry Milk
Fluid-Cottage-Cultured-Dry Whey
Fluid-Cottage-Cultured-Ice Cream
Fluld-Cottage-Cultured-Cond. Mi Ik
Fluid-Cottage-Butter-Ice Cream-
Dry Milk
Butter-Dry Milk
Buiter-Cond. Milk
"Butter-Dry Milk-Dry Whey
Butter-Natural Cheese
Butter-Dry Milk-Ice Cream
Cottage-Cond. Milk
Cottage-Cultured-Dry Milk-Dry
Whey-Fluid
Cottage-Natural Cheese
Natural Cheese-Dry Whey
Natural Cheese-Cultured-Rec. Sta.
Natural Cheese-Cond. Whey
Literature
Reported Plant Sources
Liters Waste Water
Number per 1,000 kg Milk Number
of Plants Equivalent Received of Plants
Report ing Ranee
6
1
16
10
5
20
7
-
4
8
3
3
10
-
8
1
525-1,251
_
108-9,091
1,334-6,547
834-12,543
200-5,846
776-5,563
-
1,000-3,336
984-12,835
909-1,026
5,079-7,081
>7 5-2, 135
_
751-3,336
-
Mean Reporting
676
83
3,077
2,602
7,740
2,135
2,977
-
1,985
4,720
-967
5,396
1,193
_
1,676
7,106
5
1
11
1
_
5
12
1
2
3
7
5
6
7
_
-
Identified
Plant Sources
Liters Waste Water
per 1,000 kg Milk
Equivalent Received
Ranee
317-1,868
-
434-8,507
_
-
275-959
525-7,039
801-7, 2B9
751-3,836
917-1,151
509-2,152
234-4,645
459-7,948
_
-
Mean
826
542
3,870
801
-
567
4,053
1,251
4,045
1,810
992
1,076
2,177
3,453
_
-
Liters Waste
Water per 100 kg
BODs Received
Ranse
317-1,868
_
434-8,507
_
_
275-1,384
767-13,144
-
801-7,289
917-5,529
2,285-2,852
1,259-5,534
234-4,645
709-7,948
_
-
Mean
826
542
3,886
2,093
_
676
7,427
1,968
4,045
2,502
2,444
2,669
2,177
3,536
_
-
12
9
I
19
1
801-11,518 3,545
500-4,253 2,002
1,618
834-2,519 1,735
417-6,505 2,777
1,526
2,085
3,678
5,980
617-2,819 2,002
2,319
3,678
13,861
617-2,819 2,002
2,319
1,134-3,753
542-1.126
1,401-20,333
3,786-8,040
2,210
2,783
5,921
2,619
851
2,685
2.802
1,084
1,368
6,297
9,207
6,572
5,271
1,518-3,886
709-1, U6
1,401-20,333
3,987-8,040
2,210
2,955
5,921
2,769
984
3,286
4,287
1,084
1,535
6,297
9,207
6,572
5,880
-------
TABLE 14 A
Type of_ Plant
A. Single Product
Receiving Station (Cans)
Receiving Station (Bulk)
Fluid Products
Cultured Products
Butter
Cottage Cheese
Natural Cheese
lew Cream
Ice Cream Mix
Condensed Milk
Dry Milk
Cundensed Vhey
Dry Whey
B.
Multi-products
TTuItJ-Cottage
Fluid-Cultured
Fluid-Butter
Fluid-Natural Cheese
Fluid-Ice Cream Mix-Cottage- Cultured
Fluid-Ice Cream Mix-Cond,
Milk-Cultured
Fluid-Cultured-Juice
Fluid-Cottage-Cultured
Fluid-Cottage-Ice Cream
Fluid-Eutter-Natural Cheese
Fluid-Cottage-Dry Milk
Fluid-Cottage-Cultured-Dry Whey
Fluid-Cottai>e-Cultured-Ice Cream
Fluid-Cottage-Cultured-Cond. Milk
Fluid-Cottage-Butter-Ice Cream-
Dry Milk
Butter-Dry Milk
Butter-Cond. Milk
Butter-Dry Milk-Dry Whey
Butter-Natural Cheese
Butter-Dry Milk-Ice Cream
Coctage-Cond. Milk
Cottagt-'-Cultured-Dry Milk-Dry
Whey-Fluid
Cottage-Natural Cheese
Natural Cheese-Dry Whey
Natural Cheese-Cultured-Rec. Sta.
Natural Cheese-Cond. Whey
uranary of Literature Reported and Identified Plant Source
Raw Waste V'ater Volume Data (FI'S I'nlts)
literature
Number
of Plants
Report ing
6
1
16
10
5
20
7
-
4
8
3
3
10
-
8
1
.
-
-
12
9
1
-
-
-
" " •
6
-
-
19
1
-
_
-
1
-
-
Reported Plant Sources
Gallons
Waste Water
1,000 Pounds
per
Milk
Eguiyalent Received
Rant!£'
63-150
-
13-1,090
160-785
100-1,504
24-701
93-667
-
120-400
118-1,539
109-123
609-849
69-256
-
90-400
_
_
-
-
96-1,381
60-510
-
-
-
-
_
100-302
-
-
50-780
-
-
-
-
-
-
-
Mean
81
10
369
312
928
256
357
-
238
566
116
647
143
-
201
852
-
-
425
240
194
-
-
-
_
208
-
-
333
183
-
_
_
250
-
-
Identified Plant Sources
Number
of Plants
Reporting
5
1
11
1
-
5
12
1
2
3
7
5
6
7
_
-
1
1
6
1
_
-
1
3
1
1
4
1
1
_
-
1
1
1
3
1
3
Gallons
Waste Water
1,000 Pounds
Per
Milk
Equivalent Received
Ranee
30-224
_
52-1,020
_
-
33-115
63-844
_
96-874
90-460
110-138
61-258
28-557
55-953
_
-
-
74-338
_
_
-
-
136-450
-
_
65-135
-
-
_
.
-
_
-
168-2,438
-
454-964
Mean
99
65
464
96
-
68
486
150
485
217
119
129
261
414
_
-
441
717
240
278
_
-
265
334
710
314
102
322
336
_
-
130
164
755
1,104
788
632
Gallons Waste
per 100 Poui
Water
-.ds
BODE, Received
Ranee
38-224
-
52-1,020
_
-
33-166
92-1,576
_
96-874
110-663
274-342
151-642
28-557
85-953
_ v
-
-
74-338
-
_
_
-
182-466
-
_
85-135
-
-
-
-
-
_
-
168-2^438
-
478-964
Mean
99
65
466
251
_
81
890
236
485
300
293
320
261
424
_
-
441
1,662
240
278
_
_
265
354
710
332
118
394
514
_
_
130
184
755
1,10*
788
705
Note: *Including whey dumping.
-------
Subcategory
Table 14B
Raw Waste Water Volume Attainable
Through Good In-Plant Control
1/kkg M.E. I/kg BODS gal/1000 Ib M.E. gal/IOOP Ib BODS
Receiving
Stations
Fluid Products
Cultured
Products
Butter
Cottage Cheese
Natural Cheese
Ice Cream
Mix
Ice Cream
Condensed Milk
Dry Milk
Condensed
Whey
Dry Whey
999
4663
4663
999
9243
999
2498
5413
4746
2248
1249
1249
9.6
44.9
44.9
9.6
89.0
9.6
24.0
52.1
45.7
21.6
12.0
12.0
120
560
560
120
mo
120
300
650
570
270
150
150
115.5
539.0
539.0
115.5
1068.3
115.5
288.7
625.6
548.6
259.9
144.4
144.4
56
-------
feed, and establishing explicit waste reduction programs with
defined targets and responsibilities. Improvement in those areas
generally will not require inordinate sums of money nor complex
technologies to be implemented. In fact, most waste control
measures of the type indicated will have an economic return as a
result of saving product that is otherwise wasted.
The other principal factors determining the raw waste load,
including BOD5 of the inputs and products, viscosity of
materials, and processes employed have been discussed elsewhere
in the report.
Effects
It has been generally recognized that the most serious
pollutional problem caused by dairy wastes is the depletion of
oxygen of the receiving water. This comes about as a result of
the decomposition of the organic substances contained in the
wastes. Organic substances are decomposed naturally by bacteria
and other organisms which consume dissolved oxygen in the
process. When the water does not contain sufficient dissolved
oxygen, the life of aquatic flora and fauna in the water body is
endangered.
57
-------
-------
SECTION VI
POLLUTANT PARAMETERS
Waste water Parameters of Potentia1
Pollutional Significance
i
On the basis of all evidence reviewed, it has been concluded that
the waste water parameters of potential pollutional significance
include BOD, COD, suspended solids, pH, temperature, phosphorus
in the form of phosphates, nitrogen in various forms (e.g.,
ammonia nitrogen and nitrate nitrogen), and chlorides. The
significance of these parameters and the rationale for selection
or rejection of each as a factor for which an effluent guideline
should be established are discussed below.
BQD
The majority of waste material in dairy plant waste waters is
organic in nature, consisting of milk solids and organic
components of cleaners, sanitizers and lubricants. The major
pollutional effect of such organics is depletion of the dissolved
in receiving waters. The potential of a waste for exerting this
effect irost commonly has been measured in terms of BOD, the
laboratory analysis which most closely parallels phenomena
occurring in receiving waters.
The BOD5 concentration of raw waste waters in the dairy products
processing industry typically ranges from 1,000 mg/1 to 4,000
mg/1 and the total daily loads within the industry have been
observed to range from 8.2 kg/day {18.0 Ib) to 3,045 kg/day
(6,699 Ib). This is equivalent to raw waste discharge for
municipalities of 100 to 40,000 population. Such concentrations
of BOD5 are considered excessive for direct discharge to
receiving waters, and unless the receiving waterbody is a large,
well-mixed lake or stream, the upper segment of the range of
loads poses a hazard to aquatic wildlife as a result of oxygen
depletion.
The BOD5 level of dairy wastes can be reduced by in-plant
controls and end-of-pipe treatment (including disposal on land)
that are well demonstrated and readily available. Therefore,
effluent limitations guidelines for this parameter are
justifiable and recommended for point source discharges for each
subcategory within the dairy products industry.
Biochemical oxygen demand (BOD) is a measure of the oxygen
consuming capabilities of organic matter. The BOD does not in
itself cause direct harm to a water system, but it does exert an
indirect effect by depressing the oxygen content of the water.
Sewage and other organic effluents during their processes of
decomposition exert a BOD, which can have a catastrophic effect
on the ecosystem by depleting the oxygen supply. Conditions are
reached frequently where all of the oxygen is used and the
59
-------
continuing decay process causes the production of noxious gases
such as hydrogen sulfide and methane. Water with a high BOD
indicates the presence of decomposing organic matter and
subsequent high bacterial counts that degrade its quality and
potential uses.
Dissolved oxygen (DO) is a water quality constituent that, in
appropriate concentrations, is essential not only to keep
organisms living but also to sustain species reproduction, vigor,
and the development of populations. Organisms undergo stress at
reduced DO concentrations that make them less competitive and
able to sustain their species within the aquatic environment.
For example, reduced DO concentrations have been shown to
interfere with fish population through delayed hatching of eggs,
reduced size and vigor of embryos, production of deformities in
young, interference with food digestion, acceleration of blood
clotting, decreased tolerance to certain toxicants, reduced food
efficiency and growth rate, and reduced maximum sustained
swimming speed. Fish food organisms are likewise affected
adversely in conditions with suppressed DO. Since all aerobic
aquatic organisms need a certain amount of oxygen, the
consequences of total lack of dissolved oxygen due to a high BOD
can kill all inhabitants of the affected area.
If a high BOD is present, the quality of the water is usually
visually degraded by the presence of decomposing materials and
algae blooms due to the uptake of degraded materials that form
the foodstuffs of the algal populations.
CQD
In theory, the Chemical Oxygen Demand test (an analytical
procedure employing refluxing with strong oxidizing agents)
measures all oxidizable organic materials, both non-biodegradable
and biodegradable, in a waste water. It thus has an advantage,
when compared to the BOD5 test, of measuring the refractive
organics which may cause toxicity or taste and odor problems. An
additional advantage (especially for employment as an operational
waste management tool) is that COD can be determined in a
relatively short period of time, at most a matter of several
hours not days, and thus is a measure of current operations, not
those of days past as is true for BOD. Conversely, COD has two
major disadvantages. It does not closely parallel phenomena in
receiving waters and it does not distinguish between non-
biodegradable and biodegradable materials. Thus, it does not
indicate the potential that a waste water may have for causing an
oxygen depletion in receiving waters.
Data compiled during the course of this study indicate a COD to
BOD5 ratio of approximately 2:1 for raw wastes and 4:1 for
biologically treated (e.g., activated sludge) wastes. Both of
these ratios are fairly close to those noted for typical
60
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municipal wastes and do not indicate wastes abnormally high in
refractive organics.
The decision of whether or not to include COD as a parameter to
be controlled under effluent guidelines should be based on the
answers to two questions. What is the significance of the
materials measured by COD and not by other parameters, and what
are the facts associated with treatment for removal of COD?
Historically there is little or no information to indicate
environmental problems associated with an inherent toxicity of
dairy plant wastes, the impacts on aquatic life having been
mediated through oxygen depletion attributable to biodegradable
organics. Similarly, the limited taste and odor problems have
been associated primarily with intermediate products resulting
from biological breakdown (especially under anaerobic conditions)
of the degradable organic constituents of milk. Thus, from the
standpoint of environmental effects there is little or no reason
to adopt COD as a control parameter for dairy products
processing.
Removal of refractive organics from dairy products wastes would
require utilization of special treatment techniques, such as
chemical-physical approaches designed for specific substances,
carbon adsorption and reverse osmosis. These techniques are high
in cost and subject to a number of operational problems, for
example, membrane fouling and carbon regeneration. The
significance of refractive organics in the dairy industry's
wastes does not justify imposition of such treatment.
Dairy product plants that can establish reasonably consistent
correlation between COD and BOD5 could, in the future, substitute
COD for BOD as a monitoring measurement for determining the
effectiveness of control and treatment. This is especially true
for small isolated operations that could not afford Total Organic
Carbon or Total Oxygen Demand determinations at some later date.
Total Suspended SoMds
Suspended solids in waste water have an adverse affect on the
turbidity of the receiving waters. This is particularly
noticible for waste water from dairy products due to the color of
the solids and their extreme opacity. An additional effect of
suspended solids in quiescent waters is the build-up of deposits
on the botton. This is especially objectionable when the
suspended solids are primarily organic materials, as is the case
in dairy wastes. The resulting sludge beds may exert a heavy
oxygen demand on the overlying waters, and under anaerobic
conditions their decomposition produces intermediate products
(e.g., hydrogen sulfide) which cause odor problems and are toxic
to aquatic life.
Dairy products waste waters typically contain up to 2,000 mg/1 of
suspended solids, most of which are organic particulates derived
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from the milk and other materials processed. The level of solids
in raw waste waters can be reduced by good in-plant control and
with adequate end-of-pipe biological treatment and clarification
can be reduced to acceptable concentrations in final discharge
waste waters. It is recommended, therefore, that suspended
solids be included in the parameters to be controlled under
effluent guidelines and standards.
Suspended solids include both organic and inorganic materials.
The inorganic components include sand, silt, and clay. The
organic fraction includes such materials as grease, oil, tar,
animal and vegetable fats, various fibers, sawdust, hair, and
various materials from sewers. These solids may settle out
rapidly and bottom deposits are often a mixture of both organic
and inorganic solids. They adversely affect fisheries by
covering the bottom of the stream or lake with a blanket of
material that destroys the fish-food bottom fauna or the spawning
ground of fish. Deposits containing organic materials may
deplete bottom oxygen supplies and produce hydrogen sulfide,
carbon dioxide, methane, and other noxious gases.
In raw water sources for domestic use, state and regional
agencies generally specify that suspended solids in streams shall
not be present in sufficient concentration to be objectionable or
to interfere with normal treatment processes, suspended solids
in water may interfere with many industrial processes, and cause
foaming in boilers, or encrustations on equipment exposed to
water, especially as the temperature rises. Suspended solids are
undesirable in water for textile industries; paper and pulp;
beverages; dairy products; laundries; dyeing; photography;
cooling systems, and power plants. Suspended particles also
serve as a transport mechanism for pesticides and other
substances which are readily sorbed into or onto clay particles.
Solids may be suspended in water for a time, and then settle to
the bed of the stream or lake. These settleable solids
discharged with man's wastes may be inert, slowly biodegradable
materials, or rapidly decomposable substances. While in
suspension, they increase the turbidity of the water, reduce
light penetration and impair the photosynthetic activity of
aquatic plants.
Solids in suspension are aesthetically displeasing. When they
settle to form sludge deposits on the stream or lake bed, they
are often much more damaging to the life in water, and they
retain the capacity to displease the senses. Solids, when
transformed to sludge deposits, may do a variety of damaging
things, including blanketing the stream or lake bed and thereby
destroying the living spaces for those benthic organisms that
would otherwise occupy the habitat. When of an organic and
therefore decomposable nature, solids use a portion or all of the
dissolved oxygen available in the area. Organic materials also
serve as a seemingly inexhaustible food source for sludgeworms
and associated organisms.
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Turbidity is principally a measure of the light absorbing
properties of suspended solids. It is frequently used as a
substitute method of quickly estimating the total suspended
solids when the concentration is relatively low.
pH, Acidity and Alkalinity
pH outside of an acceptable range may exert adverse effect either
through direct impact of the pH or through their role of
influencing other factors such as solubility of heavy metals.
Among the potential adverse effects of abnormal pH are direct
lethal or sub-lethal impact on aquatic life, enhancement of the
toxicity of other substances, increased corros iveness of
municipal and industrial water supplies, increased costs for
water supply treatment, increased staining problems associated
with greater solubility of substances such as iron and manganese,
and rendering water unfit for some processes such as canning or
bottling of certain foods and beverages.
Though a number of individual waste streams within a dairy
products plant may exhibit undesirably high or low pH, the
available data show that the combined discharge from dairy plants
generally fall with the acceptable range. However, monitoring
and adjustment of pH are relatively simple and inexpensive, so
there is no real reason for discharge of waste water that is
outside the acceptable range of pH.
In view of the many potential adverse effects of abnormally high
or low pH, and the ease of measurement and control, it is
recommended that pH be included in the parameters for effluent
guidelines and standards.
Acidity and alkalinity are reciprocal terms. Acidity is produced
by substances that yield hydrogen ions upon hydrolysis and
alkalinity is produced by substances that yield hydroxyl ions.
The terms "total acidity" and "total alkalinity" are often used
to express the buffering capacity of a solution. Acidity in
natural waters is caused by carbon dioxide, mineral acids, weakly
dissociated acids, and the salts of strong acids and weak bases.
Alkalinity is caused by strong bases and the salts of strong
alkalies and weak acids.
The term pH is a logarithmic expression of the concentration of
hydrogen ions. At a pH of 7, the hydrogen and hydroxyl ion
concentrations are essentially equal and the water is neutral.
Lower pH values indicate acidity while higher values indicate
alkalinity. The relationship between pH and acidity or
alkalinity is not necessarily linear or direct.
Waters with a pH below 6.0 are corrosive to water works
structures, distribution lines, and household plumbing fixtures
and can thus add such constituents to drinking water as iron.
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copper, zinc, cadmium and lead. The hydrogen ion concentration
can affect the "taste" of the water. At a low pH water tastes
"sour". The bactericidal effect of chlorine is weakened as the
pH increases, and it is advantageous to keep the pH close to 7.
This is very significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress conditions or
kill aquatic life outright. Dead fish, associated algal blooms,
and foul stenches are aesthetic liabilities of any waterway.
Even moderate changes from "acceptable" criteria limits of pH are
deleterious to some species. The relative toxicity to aquatic
life of many materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in toxicity
with a drop of 1.5 pH units. The availability of many nutrient
substances varies with the alkalinity and acidity. Ammonia is
more lethal with a higher pH.
The lacrimal fluid of the human eye has a pH of approximately 7.0
and a deviation of 0,1 pH unit from the norm may result in eye
irritation for the swimmer. Appreciable irritation will cause
severe pain.
Temperature
Available data (Table 15) indicates that temperature of raw waste
waters range between 8°C (46°F) and 38°C (100°F), with 90 percent
of the discharges ranging between 15°C (59°F) and 29°C (85°F),
These values, coupled with volumes of discharge in the industry,
indicate that neither temperature nor total heat discharge
constitute serious problems. Furthermore, there will be a
tendency for the waste waters to approach ambient temperature as
they pass through the treatment facilities that must be installed
for point source discharges to meet BOD5 limitations. Thus,
temperature has not been included in the parameters subject to
guidelines and standards.
Temperature is one of the most important and influential water
quality characteristics. Temperature determines those species
that may be present; it activates the hatching of young,
regulates their activity, and stimulates or suppresses their
growth and development; it attracts, and may kill when the water
becomes too hot or becomes chilled too suddenly* Colder water
generally suppresses development. Warmer water generally
accelerates activity and may be a primary cause of aquatic plant
nuisances when other environmental factors are suitable.
Temperature is a prime regulator of natural processes within the
water environment. It governs physiological functions in
organisms and, acting directly or indirectly in combination with
other water quality constituents, it affects aquatic life with
each change. These effects include chemical reaction rates,
enzymatic functions, molecular movements, and molecular exchanges
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between membranes within and between
and the organs of an animal.
the physiological systems
Chemical reaction rates vary with temperature and generally
increase as the temperature is increased. The solubility of
gases in water varies with temperature. Dissolved oxygen is
decreased by the decay or decomposition of dissolved organic
substances and the decay rate increases as the temperature of the
water increases reaching a maximum at about 30°C (86°F). The
temperature of stream water, even during summer, is below the
optimum for pollution-associated bacteria. Increasing the water
temperature increases the bacterial multiplication rate when the
environment is favorable and the food supply,is abundant.
Reproduction cycles may be changed significantly by increased
temperature because this function takes plage under restricted
temperature ranges. Spawning may not occur at all because
temperatures are too high. Thus, a fish population may exist in
a heated area only by continued immigration. Disregarding the
decreased reproductive potential, water temperatures need not
reach lethal levels to decimate a species. Temperatures that
favor competitors, predators, parasites, and disease can destroy
a species at levels far below those that are lethal.
Fish food organisms are altered severely when temperatures
approach or exceed 90°F. Predominant algal species change,
primary production is decreased, and bottom associated organisms
may be depleted or altered drastically in numbers and
distribution. Increased water temperatures may cause aquatic
plant nuisances when other environmental factors are favorable.
Synergistic actions of pollutants are more severe at higher water
temperatures. Given amounts of domestic sewage, refinery wastes,
oils, tars, insecticides, detergents, and fertilizers more
rapidly deplete oxygen in water at higher temperatures, and the
respective toxicities are likewise increased.
When water temperatures increase, the predominant algal species
may change from diatoms to green algae, and finally at high
temperatures to blue-green algae, because of species temperature
preferentials. Blue-green algae can cause serious odor problems.
The number and distribution of benthic organisms decreases as
water temperatures increase above 90°F, which is close to the
tolerance limit for the population. This could seriously affect
certain fish that depend on benthic organisms as a food source.
The cost of fish being attracted to heated water in winter months
may be considerable, due to fish mortalities that may result when
the fish return to the cooler water.
Rising temperatures stimulate the decomposition of sludge,
formation of sludge gas, multiplication of saprophytic bacteria
and fungi (particularly in the presence of organic wastes), and
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the consumption of oxygen by putrefactive processes, thus
affecting the esthetic value of a water course.
In general, marine water temperatures do not change as rapidly or
range as widely as those of freshwaters. Marine and estuarine
fishes, therefore, are less tolerant of temperature variation.
Although this limited ^olerance is greater in estuarine than in
open water marine species, temperature changes are more important
to those fishes in estuaries and bays than to those in.open
marine areas, because of the nursery and replenishment functions
of the estuary that can (be adversely affected by extreme
temperature changes.
Phosphorus
Phosphorus is of environmental concern because of the role it
plays in eutrophication, the threshold concentration for
stimulation of excessive algal growth generally being considered
as approximately 0.01 mg/1 to 0.25 mg/1. ' ,
Phosphorus concentrations in raw waste waters in the dairy
industry have been found to range from 12 mg/1 to 210 mg/1 with a
mean of 49 mg/1. With the reduction of phosphorus concentrations
that result from implementation of adequate in-plant control, and
the further reduction that accompanies biological treatment
(approximately 1 part per 100 parts of BOD5 removed), the
phosphorus levels associated with point source discharges in the
industry will be consistent with those in discharges from
municipal secondary treatment plants. Effluent guidelines and
standards for phosphorus are not recommended at this time.
During the past 30 years, a formidable case has developed for the
belief that increasing standing crops of aquatic plant growths,
which often interfere with water uses and are nuisances to man,
frequently are caused by increasing supplies of phosphorus. Such
phenomena are associated with a condition of accelerated
eutrophication or aging of waters. It is generally recognized
that phosphorus is not the sole cause of eutrophication, but
there is evidence to substantiate that it is frequently the key
element in all of the elements required by fresh water plants and
is generally present in the least amount relative to need.
Therefore, an increase in phosphorus allows use of other, already
present, nutrients for plant growths. Phosphorus is usually
described, for this reasons, as a "limiting factor."
i
When a plant population is stimulated in production and attains a
nuisance status, a large number of associated liabilities are
immediately apparent. Dense populations of pond weeds make
swimming dangerous. Boating and water skiing and sometimes
fishing may be eliminated because of the mass of vegetation that
serves as an physical impediment to such activities. Plant
populations have been associated with stunted fish populations
and with poor fishing. Plant nuisances emit vile stenches.
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impart tastes and odors to water supplies, reduce the efficiency
of industrial and municipal water treatment, impair aesthetic
beauty, reduce or restrict resort trade, lower waterfront
property values, cause skin rashes to man during water contact,
and serve as a desired substrate and breeding ground for flies.
Phosphorus in the elemental form is particularly toxic, and
subject to bioaccumulation in much the same way as mercury.
Colloidal elemental phosphorus will poison marine fish (causing
skin tissue breakdown and discoloration). Also, phosphorus is
capable of being concentrated and will accumulate in organs and
soft tissues. Experiments have shown that marine fish will
concentrate phosphorus from water containing as little as 1 ug/1.
Nitrogen
Nitrogen is another element whose major cause for environmental
concern stems from its role in excessive algal growth. In
addition, very high levels of nitrogen are undesirable in water
supplies and are toxic to aquatic life especially when present in
the form of ammonia.
Nitrogen is present in dairy waste waters primarily as protein
and ammonia nitrogen. Based on very limited data (Table 15) ,
ammonia nitrogen concentrations have been found to vary from 1.0
mg/1 to 13.2 mg/I and average 5,4 mg/1. As is the case for
phosphorus, reductions attained through in-plant controls and
biological treatment required to meet limitations for other
parameters will result in nitrogen concentrations in point source
discharges that are consistent with those found in discharges
from municipal secondary treatment plants. Effluent limitations
for nitrogen are not recommended for application to the dairy
products industry at the present time.
Chloride
Excessive concentrations of chloride interfere with use of waters
for municipal supplies by imparting a salty taste, for industrial
supplies by increasing corrosion, for irrigation through
phytotoxicity, and for propagation of freshwater aquatic life (if
levels are in thousands of mg/1 and variable) through disturbance
of osmotic balance.
Very limited data (Table 15) show that chloride concentrations in
raw waste waters range between 46 mg/1 and 1,930 mg/1 and average
482 mg/1. If one eliminates the very high value of 1,930 mg/1,
possibly attributable to leakage of brine from refrigeration
lines, the chloride concentrations are well below limits for any
use other than irrigation of the most sensitive plants. Chloride
is a conservative pollutant, i.e., it is not subject to
significant reduction in biological treatment systems.
Appreciable reduction of chloride would require advanced
treatment such as reverse osmosis or ion exchange.
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TABLE 15
SUMMARY OF pH, TEMPERATURE, AND CONCENTRATIONS OF NITROGEN,
PHOSPHORUS, AND CHLORIDE IONS —LITERATURE REPORTED AND
IDENTIFIED PLANT SOURCES
en
oo
Parameter
Ammonia
Nitrogen (mg/1)
Total Nitrogen (mg/1)
Phosphorus
as P04 (mg/1)
Chlorides (mg/1)
Temperature (° C)
CF)
pH
No. of
Plants
11
12
8
13
33
LITERATURE
PLANT SOURCE
Range
15-180
Mean
73
12-205 53
48-559 297
18-42 33
65-108 92
404-12.0 7.2
No. of
Plants
IDENTIFIED
PLANT SOURCE
Range
Mean
9 10-13.4 5.5
10 1-115 64
29 9-210 48
6 46-1930 483
12 8-38 24
46-100 76
33 40-10.8 7.8
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In view of the relatively low levels of chlorides encountered and
the difficulty of their removal, effluent guidelines and
standards are not recommended for chlorides.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
1 n-Plant Control Concepts
The in-plant control of water resources and waste discharges in
all types of dairy food plants involve two separate but inter-
related concepts:
1.
2.
Improving management of water resources
materials.
and waste
Engineering improvements to plant, equipment,
cessses, and ancillary systems.
pro-
Plant Management Improvement
Management is one key to the control of water resources and waste
within any given dairy plant. Management must be dedicated to
the task, develop positive action programs, and follow through in
all cases; it must clearly understand the relative role of
engineering and management supervision in plant losses.
The best modern engineering design and equipment cannot alone
provide for the control of water resources and waste within a
dairy plant. This fact was clearly evident again during this
study. A new (six-month old), high-capacity, highly automated
multi-product dairy plant, incorporating many advanced waste
reduction systems, was found to have a BOD5 level in its waste
water of more than 10 kg/kkg (10 lb/1000 Ib) of milk equivalent
processed. This unexpected and excesssive waste could be related
directly to lack of management control of the situation and poor
operating practices.
Management control of water resources and waste discharges should
involve all of the following:
Installation and use of a waste monitoring system to
evaluate progress.
- Utilization of an equipment maintenance program to
minimize all product losses.
- Utilization of a product and process scheduling system
to optimize equipment utiliztion, minimize distractions
of personnel, and assist in making supervision of the
operation possible.
Utilization of a planned quality control program to
minimize waste.
- Development of alternative uses for a wasted products.
-------
- Improvement of processes, equipment
rapidly as economically feasible.
and systems as
Waste Monitoring
The collection of continuous information concerning water usage
and waste water discharge is essential to the development of any
water and waste control program in a dairy plant. Much of the
excess water and high solids waste discharges to sewer result
from lack of information to plant personnel, supervisors and
management. In many instances, large quantities of potentially
recoverable milk solids are discharged to the drain without the
knowledge of management. Accounting systems utilized to account
for fat and solids within a dairy plant are frequently inaccurate
because of many inherent errors in sampling, analysis,
measurement of product, and package filling. The installation of
water meters and of a waste monitoring system has generally
resulted in economic recovery of lost milk solids. Recovery is
usually sufficient to pay for costs of the monitoring equipment
within a short time.
Water meters may be be installed on water lines going to all
major operating departments in order to provide water use data
for the different major operations in the plant. Such knowledge
can be used to develop specific water conservation programs in a
more intelligent manner. Some plants have found it advantageous
to put in water meters to each major process to provide even more
information and to fix responsibility for excessive water use.
Waste monitoring equipment generally should be installed at each
outfall from the plant. Wherever possible in older plants,
multiple outfalls should be combined to a common discharge point
and a sampling manhole installed in this location. where
sampling manholes are being installed for the first time in old
or new locations, attention should be given to insuring that
there is easy and convenient access to the sampling point.
Monitoring equipment generally would include, a weir to measure
flow volume and a continuous sampling device. Two types of
samplers may be utilized: (a) a proportional flow, composite
sampler such as the Trebler, or (b) a time-activated sampler that
can provide hourly individual samples. For plant control
purposes the latter can provide the waste control supervisor and
and employees with a visual daily picture of the wastes from the
plant even without sampling the turbidity, color, presence of
free fat, or sediment, such a daily evaluation can readily point
out problem areas. In the case of the time sampler it is
necessary to utilize flow data to make up a flow proportioned
composite sample for analysis.
Engineering Improvements for In-Plant Waste Control
Many equipment, process, and systems improvements can be made
within dairy food plants to provide for better control of water
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usage and waste discharges. In many cases significant
engineering changes can be made in existing plants at a minimal
expense. The application of engineering improvements must be
considered in relationship to their effect on water and waste
discharges and also on the basis of economic cost of the changes.
Many engineering improvements should be considered as "cost
recovery" expenditures, since they may provide a basis for
reclaiming resources with a real economic value and eliminating
the double charges that are involved in treating these resources
as wastes.
New plants or extensive remodeling of existing plants provide an
even greater opportunity to "engineer" water and waste reduction
systems. Incorporation of advanced engineering into new plants
provides the means for the greatest reduction in waste loads at
the most economical cost.
Existing Plants
- Equipment improvements
- Process improvements
- System improvements
New Plants or Expandsion of Existing Plants
- Plant layout and equipment selection
Waste Mangement_Through Equipment Improvements
Waste management control can be strengthened by upgrading exist-
ing equipment in plant operations. These can be divided into:
(a) improvements that have been recommended for many years and
(b) these that are new and not widely used or evaluated.
Standard Equipment Improvement Recommendations
1. Put automatic shut-off valves on all water hoses
that they cannot run when not in use.
so
2. Cover all drains with wire screens to prevent solid
materials such as nuts, fruits, cheese curd from going down the
drain.
3. Mark all hand operated valves in the plant,
especially multiport valves, to identify open, closed and
directed flow positions to minimize errors in valve operation by
personnel.
4i Identify all utility lines.
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5. Install suitable liquid level controls with
automatic pump stops at all points where overflow is likely to
occur (filler bowls, silo tanks, process vats, etc.). In very
small plants, liquid level detectors and an alarm bell may be
used,
6. Provide adequate temperature controls on coolers,
especially glycol coolers, to prevent freezing-on of the product
and subsequent product loss. In some instance high-temperature
limit controls may be installed to prevent excessive burn-on of
milk which not only increase solids losses but also increase
cleaning compound requirements.
7. All CIP lines should be checked for adequate
support. Lines should be rigidly supported to eliminate leakage
of fittings caused by excessive line vibrations. All lines
should be pitched to a given drain point*
8. Where can receiving is practiced in small plants, an
adequate drip saver should be provided between can dumping and
can washing. This should be equipped with the spray nozzle to
rinse the can with 100 ml (3-4 oz) of water. A two minute drain
period should be utilized before washing,
9. All piping around storage tanks and process areas
where pipelines are taken down for cleaning should be identified
to eliminate misassembly and dapage to parts and subsequent
leaking of product.
10. Provide proper drip shields on surface coolers
fillers so that no spilled product can reach the floor.
and
11. All external tube chest evaporators should be
designed with a tangential inlet from the tube chest to the
evaporating space. All coil or colandria evaporators should be
equipped with efficient entrainment separators.
12. "Splash discs" on top of the evaporators
prevent entrainment losses through improper pan operation.
can
13, Evaporators and condensers should be equipped,
wherever possible, with full barometic leg to eliminate sucking
water back to the condenser in case of pump or power failure.
New concepts For Consideration In Equipment Improvement for 1983
Control and New Source standards
1. Install drip shields on ice cream filling equipment
to collect frozen product during filling machine jams. Such
equipment would have to be specially designed and built at the
present time.
2. Install a system for collecting novelties from
frozen dessert novelty machines and packaging units. At the
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present time numerous types of failures, especially on stick
novelty machines, cause defective novelties to be washed down the
drain. Such defects include bad sticks, no sticks, poor stick
clamping, overfilling, and poor release. The "defective product
collection system" would have to be specially designed and custom
built at the present time.
3. since recent surveys have shown that case washers
may use up to 10% of the total water normally utilized in a total
plant operation, automatic shut-off valves on the water to the
case washer should be installed so that the case washer sprays
would shut-off when the forward line of the feeder was filled.
Many cases are exposed to long term sprays because of relatively
low rate of stacking and use of washed cases in many operations.
Another alternative to be shut-off valve would be an integrated
timer coupled to a trip switch in which the trip switch would
activate the washer sprays which would automatically shut-down
after a specified washing cycle.
4. Install a product recovery can system, attached to a
pump and piped to a product recovery tank. Such a system should
be installed near filling machines (including ice cream) to
provide a system for recovering the product from damaged cartons
or non-spoiled product return. Such product could be sold for
animal feed.
5. Develop a "non-leak" portable unit for receiving
damaged product containers. Currently used package containers
are not liquid tight and generally leak products onto the floor.
This is particularly undersiable for high solids products
materials such as ice cream.
6. Install an electrical interlock between the CIP
power cut-on switch and the switch for manual air blow down, so
that the CIP pump cannot be turned on until after the blow down
system has purged the line of product,
7. Equip filling machines for most fluid products with
a product-capture system to collect products at time of change
over from one product to another. Most fillers have a product
by-pass valve. An air-acutated by-pass valve interlocked with a
low level control could be piped to the filler product recovery
system or the container collecting the product from drip shields;
so designed that when the product in the filler bowl reaches the
minimal low level the product by-pass systems would open, the
product would drain, followed by a series of short flushing
rinses. Filler bowls could be equipped with small scale spray
devices for this purpose. The entire system could be operating
through a sequence timer. All the components of such a system
are readily available but the system would have to be designed
and built for each particular filler at the present time.
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8. In the future, there is a need to give attention to
the design of equipment such as fillers and ice cream freezers to
permit them to be fully CIP cleaned.
Waste Management Through Systems Improvements
In the context of this report a "system" is a combination of
operations involving a multiplicity of different units of equip-
ment and integrated to a common purpose which may involve one or
more of the unit processes of the dairy plant. Such systems can
be categorized into: (a) those that have been put in use in at
least one or more dairy plants, and (b) those that have not yet
been utilized but are technolgically feasible and for which
component equipment parts now exist.
(a) Waste control Systems Now In Use:
Systems which are currently in use that have a direct impact on
decreasing dairy plant wastes include the following:
- CIP cleaning systems
HTST product recovery systems
(for fluid products and ice cream)
- Air blow down
Product rinse recovery systems
Automatic processes
1. CIP - The management of cleaning systems for dairy
plants has significance to waste discharges in three respects:
(a) the amount of milk solids discharged to drain through
rinsing operations, (b) the concentration of determents in the
final waste water, and (c) the amount of milk solids discharged
to drain as the result of the cleaning opertion itself. The
cleaning of all dairy equipment, whether done by mechanical force
or hand cleaning, involves four steps: pre-rinse, cleaning, post-
rinse, and sanitizing.
Wherever possible, circualtion cleaning procedures are replacing
the hand-cleaning operations, primarily because of their greater
efficiency and concomitant result in improving product quality.
Since cleaning compounds have been shown to be deleterious to the
microflora of dairy waste treatment systems, all cleaning systems
should take into account both water utilization and cleaning
compound utilization.
In small plants where hand-cleaning cannot be economically
avoided, a system should be developed to pre-package the cleaning
compounds in amounts just sufficient to do each different type of
cleaning job in the plant. This will avoid the tendency of plant
personnel to use much more cleaning compound than necessary. A
76
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wash vat for hand cleaning should be provided that has direct
connection to the plant hot water system and incorporates a
thermostatically controlled heater to maintain the tank
temperature at or around 50°C (120°F). High-pressure spray
cleaning units should be used for hand cleaning of storage tanks
and process vessels to improve efficiency and reduce cleaning
compound usage.
Cleaning compounds should be selected for a specific type of
operation and the different types of compounds kept at a minimum
to eliminate confusion, loss of materials, and utilization of
improper substances.
Small parts such as filler parts, homogenizer parts and separator
parts from those machines needing to be hand-cleaned should be
cleaned in a well-designed COP (cleaned-out-of-place) circulation
tank cleaner equipped with a self-contained pump and a
thermostically controlled heating system.
For maximum efficiency, minimum utilization of cleaning compounds
and maximum potential use of rinse recovery systems, as much of
the plant equipment as possible should be CIP. Two types of CIP
systems are currently in use in the dairy industry:
-Single-use: the cleaning compound is added to the
cleaning solution and discharged to drain after a single
cleaning opeation.
- Multiple-use: the cleaning compound is circulated
through the equipment to be cleaned and returned to a
central cleaning tank for reutilization. The cleaning
compound concentration is maintained at a desired level
either by "recharging" or by using contactivity
measurements and automatic addition of detergent as
required.
There is a conflict within industry as to which method is best
from the viewpoint of cleaning compound (detergent) and water
usage. In principle it would appear that the reutilization of
the detergent solution should be the most economical in respect
to water and cleaning compound requirements. Under actual
practice this has not always been the case and in some instance
the highest water and cleaning compound utilization has been in
plants equipped with mutiple-use CIP systems. On the average,
single-use systems use less cleaning compound and slightly more
water than multiple or reuse systems.
a CIP system provides for maximum potential waste
in respect to product loss and detergent
Automation of
control, both
utilization. An automated CIP system is composed of necessary
supply lines, return lines, remote operated valves, flow control
pumping system, temperature control system and centralized
control unit to operate the system.
77
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These systems have to be designed with safety in mind as well as
efficiency. A major problem in most current designs is
inadequate air capacity to completely clear the lines of product
and dependency upon plant personnel to make sure that they are
used prior to initiation of the CIP cleaning operation.
2. Product Rinse Recovery - The automated CIP system and
product recovery system for the HTST pasteurizer can also be
expanded to include rinse recovery for all product lines and
receiving operations.
3, Post Rinse Utilization System - Final rinses and
sanitation water may be diverted to a holding tank for
utilization in prerinsing and wash water make-up for single use
CIP application.
4. Automated Continuous Processing - Fluid
products,including ice cream mix, can be prepared in a
continuous, sequential manner eliminating the need for special
processing vats for various products, eliminating the need to
make a change-over in water between products that are being
pasteurized. Such systms are curently in use for milk products
and could be developed for ice cream operations.
(b) New Waste Control Concepts
A number of new waste control systems using existing components
and electrical and electonic control systems may be developed in
the future to further reduce waste loads in dairy plants.
Waste Management Through Proper Plant Layout and Equipment
Selection
Proper layout and installation of equipment designed to mimimize
waste are important factors to achieve low waste and low water
consumption in new or expanded plants.
(a) Plant Layout
Whereas the principles involved apply to all dairy food plants,
they are most critical for large ones. The point is approaching
when 80% of the dairy products will be produced in less than 30%
of the plants. Thus, major waste discharges will be associated
with a relatively few very large plants. For such operations,
attention to plant layout is essential.
Some major features in plant design which will minimize waste
loads include:
1. The use of a minimum number of storage tanks. A
reduction in the number of tanks reduces the number of fittings,
valves, pipe length, and also reduces the amount of wash water
and cleaning solution required. Also, the loss due to product
adhering to the sidewalls to tanks is minimized by using fewer
78
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and larger tanks.
2. Locating equipment in a flow pattern so as to
reduce the amount of piping required. Fewer pipes mean
fewer fittings, fewer pumps and fewer places for leakage.
3. Segregation of waste discharge lines on a
departmental basis. Waste discharge lines should be designed
so that the wastes from each major plant area can be identified
and, ideally, diverted independently of other waste discharges.
This would permit identification of problems and later application
of advanced technology to divert from the sewer all excessive
discharges - such as accidental spills.
H. Storage tanks should be elevated and provide for
gravity flow to processing and filling equipment. This
allows for more complete drainage of tanks and piping, and
reduces pumping requirements.
5. Space for expansion should be provided in each
departmental areas. This will permit an orderly expansion
without having to install tanks and equipment at remote points
from existing equipment. Only the equipment needed for current
production (or production for the next three years) should be
installed at the time of building the plant. This eliminates
the tendency to operate a number of different pieces of
related equipment under-capacity to "justify" their presence
in the plant. Such surplus equipment, especially pasteurizers,
tends to increase waste loads and require additional maintenance
attention.
6. Hand-cleaned tanks should be designed to be high
enough from the floor to permit draining and rinsing.
(b) Equipment Selection
In new or remodeled plants, attention must also be given to the
selection of equipment, processes and systems to minimize water
usage and waste discharge. The following considerations are
applicable to these concepts and may be beneficial to overall
plant efficiencies and operations.
1. Evaluation of equipment for ease of cleaning.
Equipment should be designed to elimate dead space, to permit
complete draining, and be adaptable to CIP (clean in place). Use
of 3A-approved equipment is to be encouraged, since these
cleanability factors are included in the approval process.
2. . Use CIP air-actuated sanitary valves in place of
plug valves. They fall shut in case of actuator failure, reduce
leaks in piping systems, are not taken down for cleaning and
therefore receive less damage and require less maintenance. Such
valves are the key to other desirable waste management features
79
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such as automated CIP systems, automated process
recovery systems, and air blowdown systems.
3. Welded lines should be used wherever
reduce leaks by eliminating joints and fittings.
control, rinse
possible to
4. For pipes that must be disconnected, use CIP
fittings that are designed not to leak and require minimum
maintenance.
5. CIP systems should be used wherever possible. In
all new installations, these should be automated to eliminate
human errors, to control the use of cleaning compounds and
waters, to improve cleaning efficiencies and to provide basic
systems for use in future engineering proceesses for waste
control.
6. Install a central hot water system. Do not use
steam "T mixers", as they waste up to 5055 more water than a
central heating system for hot water.
7. Evaluate all available
waste mangement concepts.
processes and systems for
Waste Reduction Possible Through Improvement of Plant Management
and Plant Engineering
Assessment of the extent to which in-plant controls can reduce
dairy plant wastes is difficult, because of the many different
types of plants, the variability of management, and the lack of
an absolute model on which to base judgement. Based on limited
data, it would appear probable with current management,
equipment, processes and systems that have been utilized anywhere
in the industry, the best that could be achieved in most plants
would be a water discharge of 830 1/kkg (100 gal/ 1,000 Ib) of
milk equivalent processed, and a BOD5 discharge of 0.05 kg/kkg
(0.5 lb/100lb) of milk equivalent processed. This would be
equivalent to a BOD5 waste strength minimum of 600 mg/1. The
achievement of such levels have been demonstrated only in a few
instances in the industry and in all cases these have been in
single-product plants not involving ice cream and cottage cheese.
Waste Reduction Possible Through Management
The extent to which management can reduce water consumption and
and waste loads would depend upon a number of factors that do not
lend themselves to objective evaluation, such as the initial
quality of management, the current water and waste loads in the
operation, and the type and effiency of implementation of control
programs within the plant. No absolute values can be
ascertained. Nor is it possible to assign individual water and
waste discharge savings to specific aspects of the plant
management improvement program; rather, the problem can only be
80
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looked at subjectively in the context of its whole. The
consensus among those who have studied dairy plant waste control
recently (Harper, Zall, and Carawan) is that under many
circumstances mangement improvement can result in a reduction
equivalent to 50% of current load, see Table 16.
Although there are exceptions, there has been a general
relationship found between waste water volume and BOD5
concentrations in dairy plant waste waters. For most plant
operations the waste discharge could be reduced to a rate of
1,660 I/ kkg (200 gal/1000 Ib) of milk equivalent processed and
2.4 kg BOD5. The reductions achievable represent a real economic
return to the operation. Each kilogram of BOD5 saved represents
a savings of up to 10 cents on treatment cost and 70 cents in
cost value of raw milk. (Grade A milk at a farm price of $7 per
100 Ib.) For a 227,000 kg/day (500,000 Ib) milk plant, this
would represent a potential return of $400/day or $120,000/year
(based on 300 processing days) .
Waste Reduction Through Engineering
Assignment of values to water and waste reduction through
engineering is very difficult because of the multiplicity of
variable factors that are involved. The values arrived at in
this report are based on subjective judgment. It is assumed that
an overall reduction of about 2 kg BOD5/kkg of milk equivalent
processed is achievable in a well-managed plant through the
application of presently available equipment, processes and
systems. The values used as a base line for unit operations are
the "standard manufacturing process" waste loads based on "good
management,
reported in the 1971 Kearney report. It should be
recognized that these values were obtained on relatively limited
data and may not be generally achievable in the dairy industry as
a whole at the present time.
An example of what can be achieved through application of
engineering is shown in Figures 14 and 15. Figure 14 shows the
waste load for a fluid milk operation under normal practices of
relatively good mangement. Figure 15 shows the values for unit
operations and the plant after the following engineering changes:
Installation of drip shields on all fillers.
A central water heating system with shut-off valves on all hoses
- A product recovery for the HTST operation for start-up, change-
over, and shut-down.
- Air blown down of lines.
- A rinse recovery system.
- Collection of CIP separator sludge as solid waste.
-------
FIGURE 14
oo
no
Raw
Storage
Silo
Spperation
Tank | \ / j — |
— L rue K ^s^. i \ \ / 1 — 1
iJ— i' ^ 1^1
X r ° 20 gal; 160 g
0.2# BOD 0,8#
16 gal; 0.2#BOD 2gai.
0.08^
Storage
r-^1 naH n
Past
Storage
Silo
HTST ^ /
' \ A
al; 20 gal;
BOD 0.2# BOD
Filling
^^ OO OO L *— ' — ' u_ i-*^ ^ — . 1
Distribution S 2 gal; Conveying
Returns ^ / °-1# SOD 1 gal; 10 gal.
g/ 0.1# BOD 0.3# BOD
12 gal;
0.4$
Total 243 gal
2.35# BOD
Waste Coefficients for a Fluid Milk Operation Normal Operation.
(#BOD/1000# Milk processed gal waste water/1000#Milk processed)
-------
FIGUBE 15
Tank
Truck
oo
OD
12. gal.
0.06* BOD
Separating
*~*
Raw
Storage
Silo
\ /
FT-
HTST
1 Past
storage
Silo
\ /
O
1.8 gal.
0.01* BOD
10 gal.
0.05* BOD
40 gal
0.15*
10 gal
0.0*
DO
Storage
2 gal.
0* BOD
on
1 gal.
0.1* BOD
Filling
6 gal.
0.07* BOD
Total 102.8 gal./1000*
0.5* BOD/1000*
Waste Coefficients After Installation of Engineering Advances in a Fluid
Milk Operation ( *BOD/1000 milk processed, gal. waste water/1000* milk
processed)
-------
TABLE 16
The Effect of Management Practices on Waste Coefficients
oo
Plant Prod-acts Milk Lb BOD/1000 Lb
Ho. Manufactured Processed Milk Processed
Lb Waste Water/ Level of Explanation of Practices
Lb Mili Processed Management
Practices
MilK
Milk
Mili
1(00,COO 0.3
150,000 7.8
500,000 0.2
6 Cottage Cheese 600,000 2.0
36 Cottage Cheese 300,000
1.3
O.U
5.2
0.1
0.8
Excellent
Poor
Excellent
Good
Good
37
9
26
I*
8
10
Cottage Cheese
Ice Cream
Ice Cream
Milk
Milk, Cottage
Cheese
Milk, Cottage
650,000
17,000
3^,000
250,000
1,000,000
900,000
71
32.2
2.1
0.7
8.6
3.3
12.U
5-3
0.8
1.0
2.0
1.1
Poor
Bsor
Good
Good
Poor
Fair
Cheese
Rinses saved, hoses off,
out of use, filler drip
pans
Ko stepr taken to reduce
waste
Rinses raved, returns
excluded, filler drip
pans, cooling tower
Whey excluded, fines
screened out, wash
water to drain
Whey excluded, spilled
curd handled as solid
waste
Whey included
Rinses to drain leaks,
drips; water running-
not in use
Freezer rinses segregated
Whey & Trash water excluded,
rinses segregated, returns
to feed use
Whey excluded; many drips,
leaks, returns included
Whey excluded, good water
volume control
-------
Plant -Products Milk Ih BOD/1000 Lb Lb Waste Water/ Level of Explanation of Practices
No. Manufactured Processed Milk Processed Lb Milk Processed Management
Lb/Day Practices
kO Milk, Cottage 1,000,000 it. 12
Cheese
52 Milk, Cottage H65,000 1.8
Cheese
3 Milk U00,000 3.9
Ice Cream
Cottage Cheese
30 Milk 800,000 7.7
Ice Cream
Cottage Cheese
33 Milk 600,000 12.9
oo Ice Cream
<•" Cottage Cheese
31+ Milk 900,000 9.1
Ice Cream
Cottage Cheese
UU Milk, 300,000 0.87
Butter
50 Whey powder 500,000 0.2
56 Milk powder, 200,000 3.0
Butter
1.2 Good
1.1 Good
l.U Fair
3-5 Poor to
fair
3-3 Poor
2.8 Poor
0.8 Good
5.9 Good-
fair
2.5 Fair
Whey included, rinses
saved
Returns excluded, good
vater control
Whey & wash water ex-
tjluded, rinses excluded
Whey' excluded, sloppy
Operations , spillage ,
leaks, hoses running
Ifhey included
Whey excluded, many
leaks, drips 5 etc-.
Buttermilk excluded, few
leaks, dry floor conditions
Ho entrainment losses,
all powder handled as
solid waste, no leaks
or drips
Continuous churn, hoses
running, numerous leaks
and drips
From Harper et al, 1971
-------
Utilization of all returns for hog feed.
Utilization of a water-tight container for all damaged packaged
products.
The reductions achieved would appear to be as great as could be
conceivably possible under any currently available engineering
equipment process or systems.
The estimated reduction of waste water volume and BOD5
concentration for the various engineering aspects cited in this
report are summarized in Table 17 along with the various
suggested improvements in equipment processes and systems. In
some cases it is not possible to estimate a potential waste
reduction in value. In many instances the systems are being
installed to eliminate dependence upon people and therefore
savings relate to management aspects of the plant operation. As
in the case of waste control through management improvement, the
extent of decrease in overall waste loads would depend to a large
extent upon the current utiliztion of recommended equipment
processing systems. It must be emphasized that the incorporation
of engineering improvements without concomitant management
control can and has resulted in water and waste discharges that
are in excess of those of the dairy plant with less modern
equipment but planned management waste control.
The data in Table 17 must be considered as engineering judgement
values subject to confirmation through additional analyses that
are not available at the present time.
In a well-operated dairy plant one of the most visible sources of
organic waste is the start-up and shut-down of the pasteurizing
unit. In this respect, the utilization of a product recovery
system merits particular mention in terms of potential waste
savings. Figure 16 shows the fat losses and product loss as a
function of time during the start-up and shut-down of a 27,300
kg/hour (60,000 Ib/hour) high temperature short-time pasteurizer.
To go from complete water to complete milk or from complete milk
to complete water generally requires approximately two minutes
with the discharge of approximately 910 kg (2,000 Ib) of product
and water every time the unit is started, stopped,or changed
over in water between products. The utilization of the product
recovery system for HTST units can result in a 15% reduction in
product going to, drain.
86
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Table 17
Effect of Engineering Improvement of
Equipment^ Processes and Systems on Waste Reduction
Engineering
Improvement
Equipment
Cone-type silo
Tank
Water Shut Off
Valves
Drain Screens
Drip Saver
Estimated Waste Reduction Potential
Filler Drip
Shield
Water
760 1 (200 gal.)
Up to 50* of water
used
None
None
Require water
for operation
Variable; water
saved equivalent
to about 10 1/1
about 10 1 (10 gal/
gal) of product
Interlock
Control
Variable
BOD
73 kg (160 Ib)
Not estimable -
waste represents
spillage in most
cases
0.3 kg per 38 liter
can (0.8 Ib/ 10 gal.
1.5 kg per 38 liter
can (3.2 lb/10 gal.
can) for heavy cream
Variable - can save
up to 0.25 kg BOD5/
kkg (0.25 lb/1000 Ib)
of milk packaged; 1.0 kg
BOD5/kkg (1.0 lb/1000 Ib)
of cream packaged, in
cases of poor management
and maintenance,
reduction could be
2 to 3 times these
values.
Not calulable. LOSS
without control would
be caused only by
employee error. Such
error could result in
discharge of 1 kg BOD5
per kkg (1 lb/1000 Ib)
of milk processed, or
4 kg BOD5 per kkg
(4 lb/1000 Ib) of
heavy cream processed.
Engineering
Estimated Waste Reduction Potential
87
-------
Improvement
Equipment
Ice Cream Filler
Drip shields
Novelty Collection
System
Product Recovery
Can System
"Non-Leak"
Portable Damaged
Package Unit
Curd Saving
Unit
Filler-Product
Recovery System
Engineering
Improvement
Water
Variable - up to
20 1 per
liter (20 gal/gal)
ice cream saved
Variable - up
to 1,900 liters
500 gallons) of
water to wash
frozen novelties
down the drain
Variable; should
save 8.3 1 (2.2 gal)
of water per kkg
(2200 Ib) of milk
processed
Variable
BOD
Variable. At 6,800
1/hr, a one-minute
spill is equivalent
to 113 1 (30 gal)
of ice cream, 57 kg
(125.4 Ib) of ice
cream, or 23 kg
(50.6 Ib) of BODS
Variable - reduction
in loss depends on
efficiency of machine
On an average machine
savings should average
5-10 kg (11-22 Ib)
BOD/day.
Variable: Depends
on machine jams.
On an average
operation, should
save 0.1 kg
BODS per kk,g (0.1
lb/1000 Ib) milk
processed.
Variable; Depends on
machine jams. Should
save 0.1 kg BODS per kkg
(0.1 lb/1000 Ibf
of milk processed
Not calculable at
present time.
Variable: probably
save 0.05 kg/kkg
BODS (0.05 lb/1000 Ib)
processed.
Estimated Waste Reduction Potential
Water BOD
-------
Equipment
case washer
Control
Systems;
CIP Systems -
Re-use Type
CIP Systems -
Single Use
Should reduce water None
used about 170 1/kkg
(20 gal/1000 Ib)
milk packaged
10)6 over single use 2056 over hand-cleaning
None (1096 less
cleaning compound
under average use)
Automated Continous
Processing Save 300 liters (80
gal) water on each
product change over
6 change overs-
(1800 1 480 gal)
HTST Recovery
System
Product Rinse
Recovery
Post Rinse
Utilization
(5,000 gallon
tanks, valves,
pipes 6 controller)
Air Slowdown
Engineering
Improvement
Systgms
600 1 (160 gal)
water/day
About 2 liters
of water/kg (1 qt/
Ib) milk recovered
Approximately 5%
of water volume
of plant
0.1 kg water/kkg
(0.1 lb/1000 Ib)
of milk processed
2016 over hand-cleaning
Save 0.6 kg BOD5/kkg
(0.6 lb/1000 Ib)
milk processed
for each product
change over. Change over =
910 kg/2 min x 6 =
5,460 kg (or 2002 lb/2 min x
6 - 12,011 Ib) = 3.3 kg
(7.26 Ib) BOD5 saved
per day
0.6 kg/kkg
(0.6 lb/100 Ib)
processed
milk
0.15 kg BOD/kkg (0.15
lb/1000 Ib) milk processed
None
0.2 kg BOD/kkg
(0.2 lb/1000 Ib)
of milk processed
Estimated Waste Reduction Potential
Water BOD
89
-------
Ice Cream Rerun
System
2 1/1 (2gal/gal)
ice cream saved
(spilled ice cream
is rinsed to drain)
Variable; in most
operations, saving
in BOD5 should average
245 kg (540 Ib) BOD5/day.
90
-------
FIGURE 16
4 -
500* PRODUCT/AT 60,000 #/hr
TIME(min)
Fat losses as a function of time during start-up and shut-down of a
60,000 pound/hour HTST pasteurizer.
-------
End-o£-Pipe Waste Treatment Technology
The discussion that follows covers the technologies that can be
applied to raw waste from dairy manufacturing operations to
further reduce waste loads prior to discharge to lakes or
streams. The subj ects covered include current treatment
practices in the industry, the range of technologies available,
problems associated with treatment of dairy wastes, and the waste
reductions achievable with treatment.
Current Practices
Dairy wastes are generally amenable to biological breakdown.
Consequently, the standard practice to reduce oxygen demanding
materials in dairy waste water has been to use secondary or
biological treatment. Tertiary treatment practices in the dairy
industry - sand filtration, carbon adsorption, or other methods -
are almost nil. Systems currently used to treat dairy waste
water include:
Activated Sludge
In activated sludge systems the waste water is brought into
contact with microorganisms in a aeration chamber where thorough
mixing and provision of the oxygen required by the concentrated
population of organisms are accomplished by use of aerators.
Aerations chambers are designed with sufficient capacity to
provide a theoretical retention time that may vary with the
concentration of the waste but is generally on the order of 36
hours. The discharge from the aeration chamber passes to a
clarifier where the microorganisms are allowed to settle as a
sludge under quiescent conditions. " Most of the sludge is
returned to the aeration chamber to maintain the desired
concentration of organisms and the remainder is wasted, generally
as a solid waste following dewatering. The supernatant liquid
may be discharged as a final effluent or subjected to additional
treatment such as "polishing" (e.g., filtration) or chlorination.
Trickling Filters
In trickling filters the waste water is sprayed uniformly on the
surface of a filter composed of rock, slag or plastic media, and
as it trickles through the filter the organic matter is broken
down by an encrusting biological slime. Conventional rock or
slag beds are 1.8 to 2.4 meters (6 to 8 feet) deep. Plastic
filters are built taller and occupy less area. As the waste
passes through the filter some of the slime sloughs is carried
away, thus allowing continued exposure of a surface of active
young biota and preventing clogging of the filter by excessive
slime growth, sloughed slime generally is settled, dewatered and
disposed of as a solid waste. In the operation of most trickling
filters a major portion (up to 95 percent) of the filtrate is
recycled to increase efficiency of organic waste removal and
assure proper wetting of the filter.
92
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Aerated Lagoons
Aerated lagoons are similar in principle to activated sludge
systems except that there is generally no return of sludge.
Hence, the microbial population in the aerated basin is less than
in activated sludge tanks and retention of waste water must be
longer to attain high BOD5 reduction. A settling lagoon usually
follows the aerated lagoon to allow settling of suspended solids.
Mixing intensities are usually not as great as in activated
sludge tanks. This results in a suspended solids blanket
covering the aerated and settling lagoons which is further
attacked by aerobic and anaerobic bacteria. Periodically the
sludge blanket has to be dredged out. A clarifier may be used
between the first and second stage lagoons with the settled
sludge returned to the first stage. This both reduces the sludge
to be dredged from the second stage and improves the effiency of
the first stage by increasing the density of microorganisms.
Stabilization Ponds
Stabilization ponds are holding lagoons, 0.6 to 1.5m (2 to 5 ft.)
deep, where organic matter is biodegraded by aerobic and
anaerobic bacteria. Algae utilize sun rays and CO2 released by
bacteria to produce oxygen which in return allows aerobic
bacteria to breakdown the organic matter. In lower layers,
facultative or anaerobic bacteria further biodegrade the sludge
blanket.
Disposal On Land
Disposal on land of waste waters is an alternative which deserves
careful consideration by small operations with a rural location.
Land requirements are relatively large, but capital costs and
operational costs are low. Typical procedures are:
1. spray Irrigation - This consists of pumping and
discharging the wastes over a large land area through
system of pipes and spray nozzles. The wastes should be
sprayed over grasses or crops to avoid erosion of the
soil by the impact of the water droplets. Successful
application depends on the soil characteristic - coarse,
open-type soils are preferred to clay^type soils - the
hydraulic load, and BOD5 concentration. A rate of
application of 56 cu m/ha per day (6,000 gal/ac per day)
is considered typical.
2. Ridge and Furrow Irrigation - The disposal of dairy
wastes by ridge and furrow irrigation has been
successfully used by small plants with limited volume of
wastes. The furrows are 30 to 90 centimeters (1 to 3
ft) deep, and 30 to 90 centimeters (1 to 3 ft) wide,
spaced 0.9 to 4.6 m {3 to 15 ft) apart. Distribution to
the furrows is usually from a header ditch. Gates are
used to control the liquid depth in the furrow. To
93
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prevent soil erosion and failure of the banks, a good
cover of grass must be maintained. Odors can be
expected in warm weather, and in cold weather the ground
will not accept the same volume of flow. The need to
remove the sludge which accumulates in the ditches is an
additional problem which does not exist in spray
irrigation.
3. Irrigation by Truck - The use of tank trucks for hauling
and disposing of wastes on land is a satisfactory method
for many dairy food plants. However, the cost of
hauling generally limits the use of this method to very
small plants. Disposal on the land may be done by
driving the tank truck across the field and spraying
from the rear, or by discharging to shallow furrows
spaced a reasonable distance apart.
Anaerobic Digestion
Anaerobic digestion has been practiced in small dairies through
the use of septic tanks. In the absence of air, anaerobic
bacteria breakdown organic matter into acids then into methane
and C02. Usually a reduction period of about three days is
employed, since little added reduction takes place with more
extended retention times. Anaerobic digestion is effective in
attaining up to 50-6OX reduction when initial waste
concentrations are high, but it has serious limitations for
producing a final effluent of very high quality.
Combined Systems
Waste treatment plants combining the features of some of the
biological systems described in the preceding paragraphs have
been constructed in some dairy plants in an attempt to assure
high BOD5 reduction efficiencies at all times. Examples and
possibilities of such systems include: An activitated sludge
system followed by an aerated lagoon; trickling filter followed
by activated sludge system; activated sludge system followed by
sand filtration; and anaerobic digestion followed by one of the
aerobic techniques.
Design Characteristics
Figure 17 is a schematic flow diagram of activated sludge,
trickling filter and aerated lagoons systems which should perform
satisfactorily. Table 18 lists the recommended design parameters
for the three types of biological treatment systems. Systems
constructed in accordance with the suggested design
characteristics should result in year-round BOD5 reductions above
90 percent and are capable of producing an effluent containing 30
mg/1 or less of BOD5.
Problems, Limitations and Reliability
94
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FIGURE 17
RECOMMENDED TREATMENT SYSTEMS
FOR DAIRY WASTEWATER
ACTIVATED SLUDGE SYSTEM
TRICKLING FILTER SYSTEM
Cn
KM IHl
cloigr* I F*i»;
AERATED LAGOON SYSTEM
ton
VMtcuattr
*rr*ttri l.i »"«>
(.ttB KD/Tlcu *>
(1 Ibi.WO/lOOOfl1)
Icltllni
Cent net
tmiwHt
95
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TABLE 18
RECOMMENDED DESIGN PARAMETERS
FOR BIOLOGICAL TREATMENT OF DAIRY WASTES
ACTIVATED SLUDGE
1. Removal of floating substances.
2. Twelve-hour equalization to buffer
fluctuating BOD5 and detergent loads.
Diffused air supply to prevent acid
fermentation,
3. Activated sludge tank to provide 36 hours
retention.
»
4. Micro-organisms population in the aerated
tank to maintain a maximum loading of 0.5 Kg
BCD/Kg volatile mixed liquor suspended solids.
5. Air supply of 60 cubic meters per Kg (1,000 ft.3
per pound) BOD5 applied.
6. Nutrient nitrogen and phosphorus addition
if below BOD:N:P ratio of 100:5:1.
7. Use of defearners to prevent foam.
8. Steam injection of equalization and aerated
tanks if temperature drop impairs BOD removal
efficiency.
9. Segregation of whey and cheese wash water from
wastewater.
10. Reduction of milk waste concentration to
a minimum through in-plant control.
11. Chlorination of final effluent.
TRICKLING FILTER
1. Removal of floating substances.
2. Twelve-hour equalization to buffer
fluctuating BOD5 and detergent loads.
Diffused air supply to prevent acid
fermentation.
3. Applied BOD5 load of 32 Kg/100 m3 (20
lb./l,000 ft.3).
4. Rock size of 6 to 9 centimeters (2.5 to
3.5 inches) or equivalent plastic media
to allow proper ventilation and prevent
clogging. Diffused air supply is help-
ful. (3)
5. 100% recycle of treated effluent.
6. Nutrient nitrogen and phosphorus addition
if below BOD:N:P ratio of 100:5:1.
7. Steam injection of equalization tank if
temperature drop impairs BOD removal.
8. Winter enclosure of filter in cold regions.
9. Segregation of whey and cheese wash water
froci -wastewater.
10. Reduction of milk waste concentration to
a minimum through in-plant control.
11. Continuous dosing of filter to prevent
drying up of slime.
12. Chlorination of final effluent.
AERATED LAGOON
1. Applied BOD5 loading of 3.2 Kg
per 100m-* (2 lbs./l,000 ft.3.)
2. Air supply for sufficient oxygen
dispersion.
3. Nutrient nitrogen and phosphorus
addition if below BOD:N:P ratio
of 100:5:1.
4. Settling basin to sediment
suspended solids.
5. Segregation of whey and cheese
wash water from wastewater,
6, Reduction of milk waste concentra-
tion to a minimum through in-plant
control.
7. Chlorination of final effluent.
-------
It is recognized that biological waste treatment facilities do
not operate at constant efficiencies. Variations of the BOD5
reduction efficiencies from day to day and throughout the year
can be expected from any individual system. Factors such as BOD5
concentration, type of waste, flow, temperature, and inorganic
constituents of the effluent may affect the rate of treatment of
dairy wastes by living organisms, but the interaction of and
correlation between such factors is not fully understood.
Available data show that it is possible to achieve BOD5 reduction
efficiencies greater than 99% part of the time with almost any of
the types of biological waste treatment that are available.
However, due to high variability of the composition of dairy
effluents these same treatment systems can have BOD5 reduction
efficiencies as low as 30S8 during other times, such as after
sudden, highly concentrated loads are discharged or other causes
of severe upset occur.
To obtain consistent high BOD5 removal, it is essential to allow
microorganisms to biodegrade organic matter under favorable
operating conditions. These include properly designed and
operated treatment systems to prevent shock loads and to allow
microorganisms to function under well balanced conditions;
addition of nutrients if absent; exclusion of whey and cheese
washes; in-plant reduction of waste water BOD5 to a minimum; and
maintaining favorable temperature levels and pH whenever
possible. With such practices, consistently high reductions
should be attained and peak discharge loads should not be more
than 2 to 2-1/2 times the long-term average.
Research indicates that percent BOD5 removal may decrease with
increasing BOD5 influent concentration. In one experiment, the
BOD5 reduction efficiency of an activated sludge system decreased
significantly when influent BOD5 concentration increased beyond
2,000 mg/1. High BOD5 loading (in excess of 2000 mg/1) decreased
the concentration of gram negative organisms and encouraged the
development of a microflora that apparently could not utilize
animo acids as a nitrogen source, but only inorganic nitrogen,
such as ammonia nitrogen. Under these conditions the efficiency
of the system decreased.
Detergents at concentrations above 15 mg/1 begin to inhibit
microbial respiration, with anionic detergents showing relatively
less inhibitory effects than non-ionic and cationic surfactants.
Quite understandably, high concentrations of sanitizer are
inimical to efficient biological treatment.
Treatment of Whey
Whey constitutes the most difficult problem facing the dairy
industry in respect to meeting effluent guidelines in two
respects: (a) the supply of whey generally exceeds its market
potential at the present time and (b) whey is difficult to threat
by any of the common biological treatment methods.
Generalization about whey handling and treatment can easily be
97
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misinterpreted. In no other instances is the fact more clear
than with whey that each individual circumstance must be
evaluated in light of the particular situation existing at the
particular plant. The type of whey, accessibility to an existing
whey processing facility, volume of whey produced, location of
the plant, and the type of farm operations contingent to the
processing facility are among the factors which must be taken
into consideration in determining disposition of ' whey for a
particular plant situation.
If whey is to be processed further for feed or food, a major
factor in the handling of such whey is to prevent the development
of further acidity in the product after manufacture. This is
true of cottage cheese whey was well as sweet whey, it is a well
recognized fact that the development of acidity in the product
increases the diffiucly of drying the product. This effects is
particularly well illustrated by the recent article by Pallansch
(Proceedings Whey Products Conference, 1972) showing the
temperature at which sticking occurred as a function of lactic
acid content. Cottage cheese whey, which has I6ng been
recognized to be more difficult to dry than rennet whey/ becomes
impossible to dry at pH below 4.2 in most equipment.
Prevention of development of acidity and outgrowth of
undersirable spoilage or potential pathogens requires that whey
be cooled to about 40°F and maintained at this temperature until
processed. Whereas this can generally be achieved in most plants
where processing is conducted-in the same plant as the whey is
produced, lack of adequate cooling equipment in many small plants
will require a considerable expenditure on the part of these
plants to cool the whey. This becomes particularly a problem in
respect to the shipment of whey over long distances both in
respect to precooling and in recooling at the point of receipt.
Another problem related to this general area is a lack of a
really adequate procedure for concentrating the product at the
point of manufacture in an economical manner. Membrane
processing procedures are fine in principle and are approaching
possible application. There remains the problem of sanitation
that still is a limiting factor for almost all current membrane
processing systems now on the market. In almost all cases
further improvement in sanitation design is going to be required
to make these pieces of equipment fully adequate for
concentration of whey that is going to be subsequently used for
food or feed. This is especially true in respect to possible
fluid uses.
Whey for food use must be considered in an identical manner as
Grade A milk from a microbiological viewpoint, and cannot be
handled as a by-product. It is particularly a point for food use
that whey be cooled and maintained at 40° from the time of
manufacture until final processing to avoid the outgrowth of
undesirable organisms. Alterations in the product due to
residual proteases from th3 coagulant might develop into further
acidity, and potential development of food poisoning organisms.
98
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From a processing point of view there are a number of procedures
that are potentially available to the whey manfacturers.
However, at this point in time the only really proven method of
processing whey is its concentration and drying for food or feed
use. The market potential for whey is tied very closely to the
availability and price of skim milk powder on the commercial
market. several large scale whey drying plants have had to
either shut down or to convert from food grade to feed grade
powder as a result of increased importation of milk powder.
Alternatives in the pispostion of Whey
The following are some of the more common methods of disposing of
whey at the present time:
1- Direct return to farmers supplying the milk as feed:.
This approach is limited to very small plants whose suppliers
are in the immediate locality of the plant and are engaged in
livestock feeding. Whey generally can be fed at levels of up
to 50% substitution without creating scours or other problems
even in ruminant animals. Frequently lack of acceptability
of whey as a feed to ruminants creates problems.
2- Spray irrigation; Where feasible, the best method of
treatment of whey is through spray irrigation. Because of
the low loading required for adequate spray irrigation, the
approach is limited to plants that are located in rural areas
with adequate land and generally limited to relatively small
plants. Plants producing cottage cheese whey in excess of
100,000 Ib who previously had utilized this method of
disposal have been forced to desist from the use of spray
irrigation in such states as Vermon, New York, and Ohio. The
freezing of the ground surface in northern climates and the
run-off in thawing has been a major reason for closing down
large scale sprayi irrigation systems in the northern states.
3. T£§n.sfer to municipal treatment systems,:. For plants
located in large municipalities, where the contribution of
BOD5 to the total plant load is low (less than 10%) joint
treatment is a feasible method of treatment without
interference with the efficiency of the municipal system,
provided that shock loading is avoided. The installation of
equalization tanks is generally required by the municipality.
In a few instances it has been found desirable to cool the
whey to prevent further acid production to facilitate its
biological oxidation.
5- Concentrating and drying; At the, present time this
appears to be the most feasible procedure for the utilization
of whey as a food or feed. In 1971 in the State of Wisconsin
about 90% of all sweet whey was handled in this manner.
Problems associated are the frequent necessity to haul non-
concentrated whey long distances, lack of an adequate market
99
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for the finished product, and large capital expenditure for
the concentrating and drying equipment.
6« Electrodialysis; The electrodialysis process provides a
product of high quality for special pharmaceutical
applications, but the process is well covered by proprietory
patent and the direct market is limited.
7- Ultraf iltration and reverse osmosisj. While potentially a
very promising development, especially for the recovery of a
potentially marketable protein product, current
commercialization of this process to its full potential is
dependent upon more complete development of sanitary membrane
processing equipment as cited earlier. New developments in
sanitation and cleaning procedures plus development of
operations that operate under lower fouling conditions lends
possible promise for commercialization in the immediate
future. At the present time it is much easier to sanitize
ultrafiltration than reverse osmosis equipment.
8 • Concentration arid Plating for feed application; The
utilization of film evaporators originally developed by the
cirtus industry followed by plating of the concentrate on
bran or citrus pulp may be a relatively low cost potential in
development of an improved quality feed stuff. The
competitive position of such a product depends upon the
future economic situation in the feed grains, especially corn
and soybeans.
concentrates^: In addition to ultrafiltration,
various procedures for the preparation of protein concentrate
including polyphosphate percipitation, iron product
precipitation, CMC co-precipitation and gel filtration are
all potential methods which remain unproven as viable
commercial entities at the present time. The full
commercialization of these procedures awaits the development
of a better market for the protein product. The market for
protein product is ironically limited at the present time
because of inadequacies in economics of procedures for
providing high quality protein. The greatest potential
application, fortification of soft drinks, requires large
quantities of whey protein that cannot be supplied at
present. Therefore, soft drink manufacturers hesitate to
enter the field, whey manfacturers hesitate to develop the
processes, so that at the present time we have somewhat of a
standoff in this area.
10» Fermentation products ; The utilization of whey as a
media for the production of yeast cells as a feed and
potential food product is under commercialization at the
present time. At this point there are no data indicating the
relative economics of this process in respect to drying. The
major use for the end product at the current time is feed,
and again the market potential depends upon the comparative
100
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costs of other feed supplements and feed products including
corn and soybeans. The spent liquor from the fermentation
does constitute a potentially difficult disposal problem at
the present time. We have inadequate information in this
area.
11. Lactose modification: Numerous investigators are
currently studying the possibility of hydrolyzing lactose in
whey by soluble and by immobilized enzymes. The overall
development of this field is at least several years behind
that of memtrane processing and its success also will depend
upon the solving of microbiological and sanitation aspects of
the process. In addition, drying of lactose modified whey
becomes more difficult because of the increased colligative
property of the product and increased stickiness at the same
acidity.
12. Lactose^ A limited market for lactose is the major
factor in the full utilization of this material at the
present time. Much research is being done but a clear
solution to the problem is not yet in sight. A solution to
the the lactose utilization problem is of major concern.
Even processes that recover valuable products in the form of
whey protein result in residuals containing 80% as much BOD5
as the original whey because of the lactose. Methylation,
phosphorylation, polymerization are laboratory possibilities
at the present time. However, until the market is developed
for the finished product, commercialization of such
technologies appears to be improbable and at the best
uncertain.
Ass.o.cJ.aJ^c! With the Biological Oxidation of Whey:
Lagoons, trickling filters, and activated sludge systems are all
upset by the incorporation of whey into the waste water.
Dairy plants manufacturing whey that operate their own treatment
facilities have recognized for a long time the desirability of
keeping whey out of the treatment system. The reason for
problems with the biological oxidation of whey has been given as
a 'BOD:N ratio that is undersirable and that whey is deficient in
nitrogen. The BOD:N ratio, however, is near to 20:1, a value
considered to be satisfactory. Two recent studies in the Ohio
State University laboratories have some possible bearing on the
problem of whey treatment.
1. High BOD5 loading (in excess of 2000 mg/1 BOD) decreases
the concentration of gram negative organisms and encourages
the development of a microflora that cannot utilize amino
acides as a nitrogen source. The microflora that exist under
high BOD5 loading can use only inorganic nitrogen, such as
ammonia nitrogen. Under these conditions the efficiency of
the system decreases.
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2. The constituents present in the highest concentration in
milk wastes is lactose, and nearly all of the lactose ( 80%)
in milk is present in whey. The first step in the
degradation of lactose is:
lactase
lactose
glucose
galactose
During the manufacture of cheese, a small amount of the lactose
is degraded to glucose and galactose. Glucose is readily
utilized by the bacteria to product lactic acid, but galactose is
not as readily degraded, studies in the Ohio State University
laboratory have shown that whey contains about 0.0536 glucose and
0.3-0.45% galactose. Galactose is about 20 times more effective
as an inhibitor of lactase than lactose is as a substrate.
Galactose at a concentration of 0.4% will inhibit lactase by more
than 50%. At the same time there is some evidence, which needs
further confirmation, that galactose also stops the organisms in
the biomass from producing any more lactase enzyme.
Studies are needed under commercial conditions to
findings.
confirm these
If substantiated, methods could be developed to materially
increase the efficiency of biological treatment of dairy wastes
and permit the development of procedures to treat whey.
Studies are in progress under the auspices of the National
Science Foundation to determine if lactase treatment of milk
wastes will improve their treatability. Laboratory studies have
been completed under this grant to prove that the addition of
gram negative organisms to an activated sludge treatment system
permits removal of up to 98% BOD5 at a BOD5 loading of 3000 mg/1.
(Only about 80% reduction was possible in" the absence of the
organisms.) The organisms must be added on a regular basis,
since they cannot compete with the gram positive organisms in the
system. (A field study has shown that a treatment system for a
one million pound milk-cottage cheese plant was materially
improved by the bi-weekly addition of gram negative organisms.
The BOD5 reduction was increased from 85 to 96%; sludge age was
decreased; sludge volume decreased by 40%; and the mixed liquor
VSS were increased from 1500 to 5000 mg/1.
Advantages And Disadvantages Of Various Systems
The relative advantages, disadvantages and problems of the waste
water treatment methods utilized in the dairy industry are
summarized in Table 19.
Management Of_Dairv Waste Treatment Systems
If biological treatment systems are to operate satifactorily,
they must not only be adequately designed, but must also be
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TARLF 19
Advantages and Disadvantages of
Treatment Systems Utilized in
The Dairy Industry
ACTIVATED SLUDGE (A.S.)
Advantage*
Good SOD reduction.
Good operating flexibility.
Good reilstmce to shock
loads "hen properly de-
ligned.
Hlnlium load requireKnu .
DlladVantaBM
Subs t Bid • L capital
loves Client.
High operating colt.
Up*ets to ihoek load*.
Sludge dlipoill problca*.
Performance drop* Hlth
temp, drop.
-
TRICKLING FILTERS (T.F.)
Advantages
Good KID reduction.
Good resistance to shock
loads when properly
designed.
A.S. """ E
Disadvantages
inveitamt.
High operating coat.
Long acclimation period
•ftec shock load*.
Ponding of trickling
filters when poorly de-
•tgned and operated.
Significant land re-
Fly and odor problems.
Hh*n poorly dcmlgned and
operated. Sludge diapoHl
»lth tc^. drop.
AERATED LACtXK (A.L. )
Adyantages
Good BOD reduccinn.
loads.
Low capital tost.
and T.F.
A.S. and T.F.
Dli advantage*
Large land requlreneitt.
High power cost.
STABLIZATICK PCWDS (S.P.)
loads.
Low operating cost.
Less sludge problems than
A.-S. »nd T.F.
Disadvm taxes
BOD reduction below
A.S., T.F., and A.L.
Algae growth.
Insect problems.
Odori.
its location.
IRRIGATION
1001 treatment efficiency.
Low capital cost.
Suitable for disposal
of whey.
Disadvantages
Amount of land required
Ponding.
supplies.
Soil -clogging and compaction.
Vegetation dnage.
Odors.
Spray carry-over.
requirement that llnps be
periods".
Cold water surface Icing.
Sludge build-up (ridge and
furrow only) .
State ordinances limiting
Iti location.
ANAEROBIC DIGESTION
system.
Prevents shock loadi to pro-
Minimum operating cost.
Minimum sludge disposal
problems .
Disadvantages
Suitable only for low
BOD reduction below A.S.
problems.
CCHBLSED SYSTEMS
loads.
Disadvantages
Hijh caollal cjs: .
Hljl- operating cjsc.
Sludge disposal pmLems.
o
CO
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operated under qualified supervision and maintenance. Following
are some key points that should be observed to help maintain a
high level of performance.
(a) Suggestions Applicable To All Biological Systems
1.
2.
3.
5.
6.
7.
Exclude all whey from the treatment system and the first
wash water from cottage cheese.
If it is impossible to exclude whey from the treatment
system, a retention tank should be provided so that the
whey can be metered into the treatment system over a 24-
hour period. In this case it would be necessary to make
sure that the pH of the whey does not fall below 6.0.
Normally, this would require a neutralization process.
It would be beneficial to provide pre-aeration
dairy food plant wastes.
for all
A retention tank of sufficient size should be provided
to hold the waste water from one processing day to
equalize hydraulic and BOD5 loading. Such an equalizing
tank might well be pre-aerated.
The treatment facility should be under the direct
supervision of a properly trained employee. He should
have sufficient time and sufficient training to keep the
system in a total operating condition. It should be
recognized that in the operation of a dairy food
treatment plant there are two types of variations that
cause operating problems. The first of these are the
short term surges from accidental spillages that can be
disastrous to a treatment facility if not checked
immediately. In the hands of a skilled operator,
immediate corrective measures can be taken. The second
type is much more difficult to control and relates to
the very slow acclimatization of the biological
microflora to dairy food plant wastes. This appears to
take a minimum of about 30 days so that changes in the
composition of the waste may not show up in changes in
operating characteristics of the treatment system for 30
to 60 days.
The operating personnel should keep daily records and
operate a routine daily testing procedure which should
include as a minimum; influent and effluent pH,
influent and effluent BOD, influent and effluent
suspended solids, calculation of BOD5 and hydraulic
loading, and a log of observations on the operation of
the treatment facility.
The dairy food plant should be operated in such a manner
as to minimuze hydraulic and BODS shock loading.
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8.
Any accidental spillage in the dairy food plant should
be immediately indicated to the engineer in charge of
the treatment facility. This is particularly critical
if there is inadequate equalization capacity ahead of
the treatment facility.
9.
10.
All equipment should be kept
condition.
in good operating
Final treatment effluent may need to be chlorinated
checked for coliform organisms.
and
11.
In the development stages of planning a new treatment
facility or an expanded treatment facility, lab or pilot
scale operation of the design type should be made for at
least 60 days in the intended loading and process
region.
(b) Recommendations in Respect to Spray Irrigation
1. Spray irrigation is generally not practical in dairy
plants processing over 100,000 pounds of milk per day or
discharging over 0.5 pounds of BOD5 per thousand pounds
of milk processed.
2. Regular inspection of the soil should be made to
evaluate organic matter and microbial cell build-up in
the soil that could lead to "clogging".
3. The land used for spraying should be rotated to minimize
over-loading of the soil.
4. Regular inspection of the spray devices should be made
to eliminate clogging and uneven soil distribution over
the land surface.
5. A drain area should be located on the low side of the
irrigation field and the run-off checked on a regular
basis to determine the efficiency of the operation. If
the irrigation field is adjacent to a stream, then
regular monitoring of the stream should be made to
insure adequate operation, since it is insufficient to
assume that spray irrigation is 100% effective.
(c) suggestions Concerning Oxidation Ponds
1. Aerated lagoons have limited application in areas where
they are frozen for a period of time during the winter.
2. ^Normal loading of aerated lagoons is 2 pounds of BOD5
per day per 1000 ft3 for ponds with a 30-day retention
time. This level of loading appears to provide an
optimum ratio of microbial and algal balance in the
ponds.
105
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3.
4.
Diffusers should be regularly inspected to
inlets are not clogged.
insure that
Dissolved oxygen should be measured regularly in the
first and second aeration ponds and correlated to the
loading and to the air input to the lagoon.
(d) suggestions in Respect to Trickling Filter Systems
1.
2.
3.
4.
5.
6.
The system should be loaded between 17 and 20 Ib BOD5
per thousand cu ft with a recirculation ratio of from 8
to 10.
In northern climates, the filter should be enclosed or
otherwise protected for year-round operation.
The flow to the filter should run for 24
every 24-hour day.
hours out of
7.
All debris and solids should be prefiltered.
Inspection of the distribution system of the filter
should fce made regularly to insure a uniform
distribution of the influent.
Pre-aeration is useful in the treatment of wastes by
trickling filter procedures. Where blowers are used,
they should have a capacity of 0.5 cu ft/gal of raw
waste treated.
Filters should be inspected regularly for ponding. If
ponding occurs, it may be desirable to decrease
hydraulic flow and flush the filter with high pressure
hoses.
(e) suggestions with Relationship to the Operation
Activated Sludge Treatment System
of
an
The operator should have dissolved oxygen data available
in the pre-aeration and assimilation tanks. It would be
desirable to have the measuring equipment integrated
into the oxygenating equipment to serve as a controlling
device. Frequently, problems in respect to dairy food
plant activiated sludge treatment systems result from
lack of close attention to trends in the system, and
operation is always in reaction to changes that have
already taken place. In the case of Type-2 (stable)
foam, the operator frequently will cut the air level
back to decrease the foam only to have the treatment
system go anaerobic. Abrupt changes in aeration are to
be avoided to prevent sharp changes in operating
characteristics. One of the most difficult factors to
control in dairy food plant waste activated sludge
systems is proper aeration.
106
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2. The operator should make regular inspection of the
aerating devices to make sure that there is no clogging
of the inlets.
3. There should be intentional sludge wastage, especially
in the case of extended aeration type activated sludge
treatment. The amount of wastage may be varied
depending upon the characteristics of the sludge. One
of the most serious problems in dairy food plant
activated sludge treatment is the poor characteristics
of the sludge formed. The reasons for poor sludge
characteristics relate in part to the chemical nature of
the waste, the microbial flora and the operating
characteristics. The problem is highly complex and
step-wise procedures for control or correction of the
problem have not yet been developed.
U. The loading of the treatment plant should be in the
range of 0.2 to 0.5 Ib BOD/lb mixed liquor volatile
suspended solids (MLVSS), and in the range of 35 to 50
Ib BOD5 per thousand cu ft.
(f) Suggestions for stabilization lagoons:
1. The depth of stabilization lagoons should not be more
than three to five feet.
2. Organic loadings for northern areas should not exceed 20
Ib/aere/day. For southern areas higher loadings may be
applied, up to 40-50 Ib/acre/day.
Theoretical retention times should be 90
depending on the climate.
to 120 days.
4. In northern climates where ice coverage is encountered
for extensive periods, supplementary aeration (possibly
as simple as agitation with an outboard motor) should be
available, to assist in odor control during the period
of ice breakup.
(g) Recommendations for anaerobic digestion:
1. Retention time should approximate three days. Added
retention times are not justified by the increase in
organic reduction attained. Shorter retention times may
not furnish sufficient equalization and may result in
reduced efficiency of the methane- C02 stage.
2. Odor control must be practiced by using covers, and
venting if impervious covers are employed. Venting may
employ flaring or be as simple as passing the vented
gases through a gravel-sand-loose earth filter. If
pervious covers are employed (e.g., straw and grease
107
-------
cover or natural biological scum), venting is not
usually necessary.
Tertiary. Treatment
Even at BOD5 reduction efficiency above 90X, biological treatment
systems will generally discharge BOD5 and suspended solids at
concentrations above 20 mg/1. For further reduction of BOD,
suspended solids, and other parameters, tertiary treatment
systems may have to be added after the biological systems. This
is particularly true for compliance with 1983 guidelines
limitations. To achieve zero discharge, systems such as reverse
osmosis and ion exchange would have to be used to reduce
inorganic and organic solids that are not affected by the
biological process.
The following is a brief description of various tertiary
treatment systems that could have application in aiming at total
recycling of dairy waste water.
Sand Filtration involves the passage of water through a packed
bed of sand on gravel where the suspended solids are removed from
the water by filling the bed interstices. When the pressure drop
across the bed reaches a partial limiting value, the bed is taken
out of service and backwashed to release entrapped suspended
particles. In lieu of backwashing, the bed may be taken out of
service and the first few inches of sand removed and replaced
with fresh sand. To increase solids and colloidal removal,
chemicals may be added ahead of the sand filter.
Activated Carbon Adsorption is a process wherein trace organics
present in waste water are adsorbed physically into the pores of
the carbon. After the surface is saturated, the granular carbon
is regenerated for reuse by thermal combustion. The organics are
oxidized and released as gases off the surface pores. Activated
carbon adsorption is ideal for removal of refractory organics and
color from biological effluent.
Lime Precipitation Clarification process is primarily used for
removal of soluble phosphates by precipitating the phosphate with
the calcium of lime to produce insoluable calcium phosphate. It
may be postulated that orthophosphates are precipitated as
calcium phosphate, and polyphosphates are removed primarily by
adsorption on calcium floe. Lime is added usually as a slurry
(10#-15% solution), rapidly mixed by flocculating paddles to
enhance the size of the floe, then allowed to settle as sludge.
Besides precipitation of soluble phosphates, suspended solids and
collodial materials are also removed, resulting in a reduction of
BOD, COD and other associated matter.
With treated sewage waste having a phosphorus content of 2 to 8
mg/1, lime dosages of approximately 200 to 500 mg/1, as CaO,
reduced phosphorus content to about 0.5 mg/1.
108
-------
Ion-Exchange operates on the principle of exchanging specific
anions and cations in the waste water with nonpollutant ions on
the resin bed. After exhaustion, the resin is regenerated for
reuse by passing through it a solution having the ion removed by
waste water. Ion-exchange is used primarily for recovery of
valuable constituents and to reduce specific inorganic salt
concentration.
Reverse Osmosis process is based on the principle of applying a
pressure greater than the osmotic pressure level to force water
solvents through a suitable membrane. Under these conditions,
water with a small amount of dissolved solids passes through the
membrane. Since reverse osmosis removes organic matter, viruses,
and bacteria, and lowers dissolved inorganic solids levels,
application of this process for total water recycles has very
attractive prospects.
Ammonia Air Stripping involves spraying waste water down a column
with enforced air blowing upwards. The air strips the relatively
volatile ammonia from the water. Ammonia air stripping works
more efficiently at high pH levels and during hot weather
conditions.
Recycling System
Figure 18 gives a schematic diagram of a tertiary treatment
system that could be used for treatment of secondary waste water
for complete recycle.
For recycling of treated waste water, ammonia has no effect on
steel but is extremely corrosive to copper in the presence of a
few parts per billion of oxygen. Ammonia air-stripping and ion-
exchange are presently viewed as the most promising processes for
removing ammonia nitrogen from water.
Besides the secondary biological sludge, excess sludge from the
tertiary systems—specifically the lime precipitation
clarification process—would have to be disposed of. Sludge from
sand filtering backwash is recycled back to biological system.
Organic particles, entrapped in the activated carbon pores, are
combusted in the carbon regenerating hearths.
Pretreatment of Dairy Waste Discharged
To Municipal Sanitary Sewers
General
Dairy waste water, in contrast to many other industrial waste
waters, does not contain quantities of readily settleable
suspended solids and is generally near neutral. Hence, primary
treatment practices such as sedimentation and neutralization have
no necessary application in the case of dairy waste water.
Equalization is recommended for activated sludge and trickling
109
-------
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filter systems; however, dairy waste loads discharged to municpal
treatment plants will be equalized in the sewer lines if the
dairy waste water does not constitute a very large proportion of
the load on the municipal plant.
The best approach to reduce the load on municipal plants and
excessive surcharges is good in-plant control to reduce BOD5 and
recycling of cooling water.
However, if sanitary districts impose ordinances which can be met
only through^some degree of pretreatment, the following treatment
methods are suggested:
1. Anaerobic digestion.
2. High-rate trickling filters and activated
sludge systems.
3. Stabilization ponds.
4. Aerated ponds
5. Chemical treatment
Anaerobic digestion could be applicable to small plants
discharging low volume waste. High-rate trickling filters and
activated sludge systems require high capital outlay and have
appreciable operating costs. Stabilization ponds and aerated
ponds require considerable land and will usually be impractical
for dairy plants located in cites. Chemical treatment will
require a high capital outlay and extremely high operating cost,
especially with sludge disposal. In regard to efficiency,
anaeorbic digestion and stabilization ponds will attain less BOD5
reduction. However they could eliminate appreciable BOD5 at very
long retention periods.
If the dairy waste is a significant part of the total load being
treated by a municipal plant, it is necessary that whey be
segregated to avoid the risk of upsetting the system.
Hexane Solubles
Some municipalities across the country are imposing tight
restrictions on hexane soluble fats, oils and grease. Waste
containing mineral oils discharged by the chemical and
petrochemical industries and other sources inhibit the
respiration of microorganisms. However, fat in dairy waste water
does not exhibit such an inhibitory effect. Appreciable
quantities of dairy fat are being treated successfully
biologically with no noticeable effects on microorganisms (see
Table 20).
Although large quantities of floating fats and grease could
potentially clog or stick to the walls cf sewer lines, dairy fat
111
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TABLE 20
EFFECT OF MILK LIPIDS ON THE EFFICIENCY
OF
BIOLOGICAL OXIDATION OF MILK WASTES
Products Mfe.
Milk, c.c., cond.,
milk p.
Cheese
Milk
iiilk + c.c.
Milk + c.c.
Milk + Ice c.
Ice cream
Italian Cheese
BOD
Type of Waste Influent
Treatment me /I
Activated sludge 1,750
Aerated lagoon 1,200
Activated sludge
+ lagoon 1,500
Activated sludge
+ lagoon 2,000
Activated sludge 2,250
Activated sludge 3,000
Trickling filter 1,100
Septic tank and
activated
sludge 827
Fat Percent
Influent Reduct ion
me/1 of BOD
496 98.0
350* 97.5
308* 99.9
560* 99.0
787 96.0
1,250 98.0
540 98.0
415 98.0
BOD
Effluent
me/1
35
30
20
20
90
60
22
14
Fat
Effluent
me/1
1
1
1
I1
1
1
1
1
Note: * Fat values calculated as minimum levels based on type of operation and BOD loading.
Values may vary +10%.
No data.
Nomenclautre
c.c.:
cond.:
milk p.:
ice c.:
cottage cheese
condensed milk
milk powder
ice cream
-------
does not contain inhibitory substances or toxic heavy metals that
could upset a municipal treatment system. Sanitary districts
should recognize the difference between the potential detrimental
effects of mineral-based versus milk-based fats, oils and grease
in applying their ordinances. A test that distinguishes between
those sources of fatty matter should be developed, since mineral
oil and dairy fat are both solubilized in the hexane test
currently used for control purposes.
Performance Of Dairy Waste Treatment^_Svstems
Biological Treatment
Performance data .for some dairy treatment systems currently
meeting recommended guideline limitations. It will be noted that
a variety of systems is represented in Table 21.
One data source for sand filtration showed average reductions of
81.056 for BOD and 95.5% for suspended solids. Sand filtration
removes not only suspended solids but also associated BOD, COD,
turbidity, color, bacteria and other matter.
Tertiary Treatment
Table 22 gives a general comparison of tertiary treatment systems
efficiency to remove specific pollution parameters.
Table 23 gives some further insight of the efficiencies of
tertiary treatment systems. It shows reductions produced after
passage of biological effluent through sand filtration and
activated carbon at the South Tahoe, California, treatment plant.
The effluent from the conventional activated sludge process is
treated with alum and polyelectrolyte prior to its passage
through a multi-media sand filter.
113
-------
Table 21
Subcateoon'es Present
Cottage Cheese, Cultured
Products. Fluid Products
Fluid Products, Cultured
Products, Cottage Cheese,
Condensed & Dry M1lk
Natural Cheese
Natural Cheese, Condensed
Whey, Dry Whey
Condensed Whey, Dry Whey
(plus lactose processing)
Condensed Whey, Dry Whey
(plus lactose processing)
Condensed Whey, Dry Whey
Condensed Whey
Butter, Condensed
H1lk. Dry Milk
Natural Cheese, Butter
Condensed Whey, Dry Whey
Treatment
Equalization, Activated
Sludge, Clarification
Activated Sludge
Anaerobic Digestion,
Activated Sludge, Sand
Filtration
Activated Sludge
Two Stage Trickling
Filter
Two Stage Aerated
Lagoon
Two Stage Aerated Lagoon
Two Stage Aerated Lagoon
Trickling Filter, Polishing
Pond
Anaerobic Digestion,
Stabilization Lagoon,
Spray Irrigation
tained by Exemplary Operations
g Guidelines Limitations
Plant Discharge
Ib/dav
BODS
8.71
19.99
0.12
11.97
2.60
11.55
10.98
3.10
ing 4.45
TSS
N/A
N/A
0.16
N/A
N/A
109.50
N/A
7.00
4.45
1977
BODS
17.05
59.76
1.51
12.85
8.00*
12.00*
14.40
4.00
45.30
Limitations
•Ib/dav
TSS
25.58
89.64
2.26
19.06
12.00*
18.00*
21.60
6.00
67.95
1983
BODS
5.68
19.92
0.42
4.28
2.70*
4.00*
4.80
1.33
10.41
Limitations
Ib/dav
TSS
7.10
24.90
0.52
5.35
3.40*
5.00*
5.00
1.66
13.01
No Discharge
19.86
29.79
4.97
6.21
*Does not include any allowance for lactose processing.
-------
TABLE 22
GENERAL COMPARISON OF TERTIARY TREATMENT SYSTEMS EFFICIENCY
Parameter
BOD
COD
s.s.
T.D.S.
Nitrogen
Phosporus
NH3
Color
Notes : ***
Lime Precipi-
tation
**
*
**
**
*
***
*
**
Excellent
Sand Filtra-
tion
**
*
***
*
*
***+
*
**+
Carbon Ion
Absorption Exchange
*** *
*** *
** **
* ***
* *
*r **
* ***
"rfffyC "X
(140)
Reverse
Osmosis
***
***
***
***
**
**
**
**
Ammonia
Air
Stripping
*
*
*
*
*
*
**#
*
** Good
* Fair to Poor
+ Based on addition of chemicals (e.g. alum and polyelectrolyte)
(1) Total Dissolved Solids of Secondary Effluent.
-------
TABLE ?3
PLANT PERFORMANCE DATA FOR THE TERTIARY TREATMENT PLANT AT
SOUTH TAHOE, CALIFORNIA (141)
Quality Parameter
Biochemical oxygen demand
(nag/liter)
Chemical oxygen demand (mg/
liter)
Total organic carbon (mg/
liter)
Suspended solids (rag/liter)
Turbidity (units)
Phosphates (mg/liter)
ABS (rag/liter)
Coliforn bacteria
(M.P.N./100 ml)
Color (units)
Odor
Raw Waste-
Water Effluent
200-400
400-600
160-350
50-150
15-35
2-4
15,000,000
High
Odor
Activated Sludge
Plant Effluent
20-40
80-160
5-20
30-70
25-30
1.1-2.9
150,000
High
Odor
Water Reclamation Plant
Sand Bed
Effluent
Under 1
30-60
10-18
Under 0.5
0.5-3.0
0.1-1.0
1.1-2.9
15
10-30
Odor
Chlorinated Carbon
Column Effluent
Under 1
3-16
1-6
Under 0.5
Under 0.5
0.1-1.0
0.002-0.5
Under 2.2
Colorless
Odorless
-------
SECTION VIII
COST, ENERGY _AND NON-WATER QUALITY ASPECTS
Control
of ^In
An accurate assessment of the costs of in-plant improvement is
not possible tecause of the following:
- broad variation in types and sizes of plants
- geographical differences in plant location
- difference among plants in respect to their current
implementation of necessary management and
engineering improvements
- management limitations
However, an estimate of costs is provided in this section for
engineering improvement areas. These values should be used as
general guidelines only; they could vary substantially in
individual situations.
For the same reasons indicated above, it is not possible to
relate costs incurred for in-plant control to specific reduction
benefits achievable (as estimated in Section VII) on an industry
or subcategroy basis. However, many of the in-plant improvements
that have been suggested in this report as means to achieve the
effluent limitation guidelines have been successfully implemented
in a number of plants at a net economic return as a result of
product saved. It may be reasonably assumed, therefore that the
in-plant controls necessary to achieve the suggested effluent
guidelines in many plants will cost little or no more than
economic return they will achieve. Exceptional cases in all
probability will involve the economic disposal of whey in plants
producing cottage or natural cheese.
Cost of Equipment, Process and Systems Improvements
The costs involved in making the engineering improvements
suggested in Section VII are equally difficult to ascertain with
precision, and certainly will change with plant location, with
size and type of plant, and with the supplier of the equipment.
Estimated values are based on figures obtained from various major
manufacturers of dairy plant equipment, and are presented in
Table 24. They should be considered as guidelines values; the
cost in individual situations could be as much as 20% higher than
the quoted figures.
117
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Table 24
ESTIMATED COST OF ENGINEERING IMPROVEMENTS OF EQUIPMENT,
AND SYSTEMS TO REDUCE WASTE.
Item
Standard Equipment
Automatic Water
Shut-Off Valves
Drain Screens
Unit Cost
$15-25
valve
$ 12
Total Cost for a
230,000 kg/day
(500,000 Ib/day)
dairy plant
$300
$150
(Note: Not recommended by equipment suppliers, because they plup-up
too easily. New design needed for drain. Quick estimate of non-fouling
drain system would be $150/drain).
Liquid Level Control
Temperature Controller
CIP Line support
Drip Saver (can
dumping)
$300/probe
$1,000
$330/100m
($100/100 ft.)
$150
$6,000 (min)
$2,000
(Included in line
installation cost
of $2500/valve)
(Not applicable)
Evaporator Improvement
Included today in basic cost of equipment
Filler Dripshield
(Cost depends on size
and type of filler)
$50-250
$1,500
(Drip shield Note: These items would have to be specially designed and
may cause redesign in filler.)
Evaporator Improvement
New Equipment Concepts
ice cream Filler
Included today in basic cost of equipment
$1,000
$3,000
118
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Item
Table 2U (con't)
UnitCost
Total Cost for a
230,000 kg/day
(500,00 Ib/day
dairy plant
Novelty Collection System
Case Washer
Water Control
Product Recovery Can
System (including 20
gallon container, piping,
fittings, and controls)
"Non-leak" Damaged Package
Unit; complete with pump
valve, level controller,
spray device.
Interlock control between
CIP and air blow down
Filler Product Recovery
System
CIP Fittings
and
Controls
Equipment manufacturers cannot
estimate cost at this time. Would
require special design.
$ 550
$2,000/unit
$2,500
$ 700
$2,700
$ 25-30/
fitting
$ 300-500/
control
$ 550
$6,000
$7,500
$4,200
$10,800
Improvement of Systems based on Existing Components
CIP System
- Revised type
$10,000/
unit
$30,000
119
-------
(con't)
Item
CIP System
-Single-use type
HTST Receiving System
Air Blow Down System
Won-Lubricated
Air compression
Air Blow Down Unit
(filler, valve, etc.)
Product Rinse Recovery
Post Rinse utilization
Automated Continuous
Processing
$15,000
unit
$10,000
$ 5,000
$ 6,000
$ 300/unit
$10,000
$ 7,500
$10,500
Application of New Systems Concepts
High Solids
Recovery System, including
2 valves
50,000 gal tank and
turbidity inter controls
ice Cream Recovery
System, including
250 gal tank and
2 valves/unit with piping 6 fitting
Total Cost for a
230,000 kg/day
(500,00 Ib/day)
daiEy,plant
$ 30,000
$ 20,000
$ 7,800
$ 10,000
$ 7,500
$ 10,500
$104,000
Other new systems
$ 13,000
Cost not determinable at present time
120
-------
Item
Standard 190,000 1
(50,000 gal)
Silo tank
Cone shaped 190,000 1
(50,000 gal)
Silo tank
Standard 78,000 1
(20,000 gal)
Silo Pasteurizer Surge Tank
Standard 78,000 1
(20,000 gal)
silo pasteurizer Surge
Tank
Welded pipelines, fittings,
controls, installation;
4 products only —
30 valves
Pull product line—
150 Valves
Drain Segregation
Table 24 (con't)
Unit Cost
$50,000
$60,000
$20,000
Air Actuated Valves
Central Hot Water
$24,000
$ 2,500 x No.
of air-acutated
valves
Increase in Con-
struction cost
estimated at $.257
square ft. include
manholes for each
department and drain
junction.
$700-8007valve
$330-8207100m
($100-250/100 ft.)
$3,000-10,000
Total Cost for a
230,000 kg/day
(500,00 Ib7day)
dairy plant
$100,000
$120,000
$100,000
$120,000
$ 75,000
$375,000
$ 50,000
$ 7,500
121
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Treatment
Biological Treatment
A summary of the estimated capital costs and operating costs for
activated sludge, trickling filter and aerated lagoon systems are
shown in Figures 19 through 23. The data are based on 1971
costs. Operating costs include power, chlorine, materials and
supplies, laboratory supplies, sludge hauling, maintenance,
direct labor, and generally 10-year straight-line depreciation,
Cost estimates for biological waste treatment systems are based
on model plants covering various discharge conditions represen-
tative of the dairy industry. Specifically, raw waste BOD5 con-
centration of 500 mg/1, 1000 mg/1, 1500 mg/1 and 2000 mg/l" were
selected, each at a flow volume of 187 cu m/day, 375 cu m/day,
935 cu m/day, 1872 cu m/day (50,000 gpd, 100,000 gpd, 250,000 gpd
and 500,000 gpd). Cost analysis for waste water volumes of 187
cu m/day (50,000 gpd) and less were based on treatment by means
of package plants. Package activated sludge was considered
although packed towers could be as efficient.
Substantial savings could be realized through use of prefab-
ricated plants for low volume discharge. Although field-
instituted treatment systems cost more even at larger capacities,
they would generally provide greater operational flexibility,
greater resistance to shock loads and flow surges, better
expansion possibilities and higher average treatment
efficiencies. Cost estimates assume plants designed in
accordance with the parameters specified in Table 16, Section
VII.
Capital cost estimates for aerated lagoons for the four BOD
cases — 500 mg/1, 1000, mg/1, 1500 mg/1 and 2000 mg/1 -- were
almost identical. Therefore, one case is indicated, namely 2000
mg/1 BOD5 at 187 cu m/day, 375 cu m/day, 935 cu m/day, 1872 cu
m/day (507000 gpd, 100,000 gpd, 250,000 gpd and 500,000 pgd) .
Also operating cost estimates for the four BOD5 concentrations
were almost identical and only the operating cost~for the model
lagoons receiving 2,000 mg/1 BOD5 is indicated. Fig* 22 shows
operating costs including 10-year straight line depreciation.
Fig. 23 shows operating costs excluding depreciation.
Capital cost estimates for a treatment system consisting of
anaerobic digestion followed by a stabilization lagoon were based
on the following design parameters: retention times of 3-day and
120-days respectively, for anaerobic digestion and stabilization,
an average depth of 3 feet for the stabilization lagoon, and an
organic loading limit of 20 Ib BOD5/acre/day for the
stabilization lagoon. The estimates incorporate land at
$1000/acre, the costs of mechanical equipment (pumps, a 5 or 10
horsepower aeration at the discharge point from anaerobic
digestion, and piping) , and the costs of construction.
Investment is estimated at $7,600, $13,000 and $21,000 for
122
-------
FIGURE 19
CAPITAL COST (AUGUST, 1971)
ACTIVATED SLUDGE SYSTEMS (FOR DAIRY WASTEWATER)
.7 .a •» 10
FLOW (375 cu m/day)(100,000 GPD.)
e 7 a 9 10
Includes: Raw wastewater pumping, half-day equalization with diffused air,
aeration basin (36 hours) with diffused air supply system, settling, chlori-
nation feed system, chlorinatlon contact basin, sludge recycle, aerobic sludge
digestion, sludge holding tank, sand-bed drying with enclosure and fans,
under-drain sand-bed pumping, laboratory, garage and shop facilities,
yardwork, engineering and land. Package treatment system does not
include sand beds, laboratory, garage and land cost.
123
-------
FIGURE 20
CAPITAL COST (AUGUST, 1971)
TRICKLING FILTER SYSTEM (FOR DAIRY WASTEWATER)
7 0 e 10
FLCW (375 cu m/day)(100,000 GPD.)
Includes: Raw wastewater pumping, half-day equalization with diffused air,
trickling filter, settling chlorination feed system, chlorination contact
basin, recirculation pumping, sludge pumping, sludge holding tank, sand bed
drying with enclosure and fans, garage and facility, yardwork, engineering
and land.
124
-------
FIGURE 21
CAPITAL COST (AUGUST, 1971)
AERATED LAGOON (FOR DAIRY WASTEWATER)
,A .5 , 6 .7 ,S .9 1p 2 3
FLOW (375 cu m/day)(100,000 GPD.)
6 7 S 9 1O
Includes: Raw wastewater pumping, aeration lagoon with high-speed floating
surface aerators, concrete embankment protection, settling basin, chlori-
nation contact basin, engineering and land.
125
-------
OPERATING COST (c/1,000 GAt.)
o
H
VI
£3
o
en
H
o
w
H
W
O
H
CO
05
W
E3
O -
2 S W
M O £-*
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w o s
u < w
-H
td
«
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O
3
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fd
H
O
CU
O
O
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O
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y
u
o
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(1)
TJ
C
00
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JJ 0)
dJtJ
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C
I O
4J-O
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-------
FIGURE 23
OPERATING COSTS (AUGUST 1971)
ACTIVATED SLUDGE, TRICKLING FILTER
AND AERATED LAGOON SYSTEMS
(FOR DAIRY WASTEWATER)
A S 6 7 8 9 1O
FLOW (375 cu ra/day) (100,000 GPD)
(Excluding Depreciation or Amortization.)
Package treatment system does not include sand beds,
laboratory and shop facilities.
127
-------
discharges of 10,000 gal/day (50 Ib/day BOD5 raw waste), 40,000
gal/day (200 Ib/day BODS BOD5 raw waste), 40,000 gal/day (200
Ib/day BOD5) respectively. Annual operating costs (power, sludge
removal and general maintenance) for these discharges are
estimated to be $2,500 and $3,500 and $6,000.
Irrigation
Investment and costs were developed for three levels of waste
water discharge: 10, 40 and 80 thousand gallons per operating
day. It is assumed that the maximum daily discharge per acre is
20,000 gallons (0.062 ft or 0.74 in/day) or 150 pounds BOD5.
Although these levels may be considered high, no problems should
be encountered if the soil is a gravel, sand, or sandy loam. In
tighter soils both hydraulic and organic loadings must be
reduced, typically to 4000-6000 gallons and 30-50 Ib BOD5/acre.
Such reductions in loadings would result in higher capital and
operational costs (e.g., the costs for 10,000 gallons per day
would approximate those for 40,000 in the account that follows).
During the winter months, it may be necessary to reduce the waste
water-BOD application per acre, particularly in the Lake States
region where many plants are located.
Other assumptions are (1) minimum in-plant changes to reduce
waste water or BOD discharge, (2) waste water and BOD discharge
coefficients per 1,000 pounds of M.E. are those used in the DPRA
study (phase II, table v-1) , (3) and all plants operate 250 days
a year.
Spray irrigation is more expensive to operate than a ridge and
furrow system that does not require pumping. Spray irrigation
investment for processing plants discharging 10,000 GPD is
$2,500-2,750, 40,000 GPD is $4,200-$5,200 and 80,000 GPD is
$7,000-$8,000. If whey is discharged with the cheese plant waste
water, the investments are $3,250, $7,200 and $13,000
respectively because of the need for additional land. Annual
total operating costs are $1,550 for the 10,000 GPD, $2,850 for
the 40,000 GPD, and $4,600 for the 80,000 GPD of waste discharge.
For the cheese plants discharging whey with the waste water, the
annual total cost are $1,600, $3,100, and $5,200 respectively.
About 70 percent of these costs are variable and the remainder
fixed.
On a per 1,000 pounds M.E. basis, the costs differ depending on
the product manufactured. For evaporated milk, ice cream, and
fluid plants, the cost decreases from 30 cents per 1,000 pounds
of M.E. throughput to 14 cents for the 40,000 GPD discharge and
11 cents for the 80,000 GPD discharge. Butter-powder plant costs
per 1,000 pounds M.E. decrease with increasing plant size and are
20, 10 and 8 cents respectively. The cost of cheese plants
without rwhey in the effluent are 14, 6, and 5 cents per 1,000
pounds of M.E., but the cost for the cheese plants discharging
10,000 gallons of waste water including whey is 70 cents, 35
cents for the 40,000 GPD and 29 cents for the 80,000 GPD.
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The ridge and furrow costs are lower and the economies of size
encountered for spray irrigation are not evident. Investment for
ditching and tiling land, the land itself and ditching to the
disposal site for 10,000 GPD is $1,600 (one-half acre) for fluid,
ice cream, evaporated milk and cheese without whey discharge
plants, $3,200 for butter plants and $6,400 for cheese plants
discharging whey. The investments for the 40,000 and 80,000 GPD
discharge are respectively four and eight times the investment
figures for the 10,000 GPD plants. Annual operating costs
(total) are assumed to be 20 percent of the total investment.
This may be considered high but these systems do require more
attention than they generally receive to keep them operating
properly at all times.
On a per 1,000 pounds of M.E. basis, the cost is 7 cents for
fluid, evaporated milk and ice cream plants regardless of the
size. The cost is 8 cents per 1,000 pounds M.E. for butter-
powder, 3 cents per 1,000 pounds M.E. for cheese plants without
whey discharge, and 55 cents per 1,000 pounds M.E. for cheese
plants with all whey in the effluent. In any case, the cost per
pound of finished product is very small.
Tertiary Treatment
For further reduction of BOD, suspended solids, phosphorus, and
other parameters which biological systems cannot remove, tertiary
treatment systems would have to be used.
The capital and operating costs for such tertiary systems are
given in Table 25. The operating costs include ten-year straight
line depreciation costs. The total capital and operating cost
represent the costs required for treatment of secondary waste
water for use in a complete recycle process. Of the procedures
in Table 25, only sand filtration is predicted for compliance
with the guidelines; and that only for 1983 limitations and new
source performance standards.
Economic Considerations
Today many waste water treatment plants of approximately the same
BOD-removal capacity vary as much as five fold in installed
capital investment. If due consideration is not given to
economic evaluation of various construction and equipment
choices, an excessive capital investment and high operating
expense usually result. The engineer is faced with defining the
problem, determining the possible solutions, economically
evaluating the alternatives and choosing the individual systems
that, when combined, will yield the most economical waste water
treatment process. Both capital investment and operating cost
must be considered carefully since it is sometimes more
economical to invest more capital initially in order to realize a
reduced yearly operating cost.
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Of the three biological systems, that provide refined treatment,
namely, activated sludge, trickling filters and aerated lagoons,
the aerated lagoon system provides 1-he most economical approach.
Investment can be minimized by providing weatherproof equipment
rather than buildings for equipment protection. Where buildings
are required, prefabricated steel structures set on concrete
slabs are economically used. Plants discharging less than 375 cu
m/day (100,000 GPD) should consider using package treatment
systems. Such treatment systems could result in capital and
operating costs savings.
Small plants in rural locations should consider the more land
oriented approaches (irrigation or a combined anaerobic digestion
- stabilization lagoon system) as a solution for waste water
treatment. If suitable land is readily available, satisfactory
waste discharge levels may be attained at lower capital
investment and operating costs, and without the operational
problems and adjustments associated with the more sophisticated
systems that require employment of a skilled waste treatment
operator.
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Lime, precipitation
clarification
Recarbonation
Sand filtration
Reverse osmosis
Activated carbon
Total
Table 25
Tertiary Treatment Systems
Cost
Estimated capital Cost J1971 Cost)
0.1
^ion
i 49
ripping 53
28
i 28
i 111
>n 139
108
Estimated operating Cost*
0.1
;ion
i 17.8
ripping 16.1
10.9
i 19.9
I 70.7
>n 58.8
194.2
Flow (mcrd)
0.5
($ 1000)
80
94
39
79
467
3*2
1,106
(1971 Cost)
Flow (mad)
0.5
(0/1,000 qal)
9.1
8.9
4.5
15.9
50.5
34.8
123.7
1.0
120
125
49
125
858
521.
1,805
1.0
7.8
6.2
3.5
13.6
42.6
29.6
103.3
Lime precipitation
clarification
Recarbonation
Sand filtration
Reverse osmosis
Activated carton
Total
*Includes 10-year depreciation cost,
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Plant layout should always receive careful consideration. Simple
equipment rearrangement can save many feet of expensive pipe and
electrical conductors as well as reducing the distances plant
operators must travel. Maintenance costs are reduced by
providing equipment-removal devices such as monorails to aid in
moving large motors and speed reducers to shop areas for
maintenance. When designing pumping stations and piping systems,
an investigation should be made to determine whether the use of
small pipe, which creates large headlosses but which is low in
capital investment, is justified over the reverse situation.
Often a larger capital investment is justified because of lower
operating costs.
Table 26 depicts the relative costs of the three biological
treatment systems as practiced in the chemical industry based on
consistent unit land and construction costs for each process.
Table 26
Biological System Cost Ccmparisions
As Applied in the Chemical Industry
Cost Ratio (relative to 1.0 as
lowest cost system}
Land requirement
Capital Investment
Operating Cost
Manpower
Maintenance
Chemical Usage
Power
Sludge Disposal
Activated
Sludge
~1.0
1.8-2.5
2.5-5.5
6.0-12.0
1.2+
40-100
50-150
Trickling
lo-1.4
1.8-5.5
2.2-5.0
4.0-8.0
1.1 +
1.0
50-150
Aerated
Lagoons
2.0-100
1.0
1.0
1.0
1.0
50-300
1.0
Non-Water Quality Aspects of
Dairy Waste Treatment
The main non-water pollutional problem associated with treatment
of dairy wastes is the disposal of sludge from the biological
oxidation systems. Varying amounts of sludge are produced by the
different types of biological systems. Activated sludge systems
and trickling filters produce sludge that needs to be handled
almost daily.
Waste sludge from activated sludge systems generally contains
about 1% solids. The amount of sludge produced ranges between
0.05 to 0.5kg solids per kg BOD5 removed. For extended aeration
systems about 0.1 kg solids will be produced per kg BOD5 removed.
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Sludge from trickling filters consists of slime sloughed off the
filter bed. This sludge settles faster than activated sludge and
compacts at solids concentrations greater than 1X solids. The
amount of sludge generated will be less than that produced by
activated sludge systems.
Aerobic and anaerobic digestion of sludge generated from
activated sludge systems is recommended to render it innocuous,
thicken it, and improve its dewatering characteristics. Sludge
thickening can preceed digestion to improve the digestion
operations. Digested activated sludge and thickened trickling
filter sludges can be vacuum-filtered, centrifuged or dried on
sand beds to increase their sclids content for better
"handleability" before final disposal.
Energy Requirements
The energy required to comply with the effluent guidelines
and standard of performance is largely that for pumping and
aeration associated with treatment facilities. The energy
requirements associated with in-plant control are so negligible
as to be virtually undetectable in the over all power consumption
in dairy products processing plants.
Based on biological treatment (e.g., extended aeration) for
the portion of the industry that constitutes point source
discharges, and including operation of treatment facilities
presently in place, the power demand to meet the 1977 limitations
is estimated to be 145,000 kwh/day. An additional 3100 kwh/day
would be required for compliance with 19 83 limitations.
Depending on the size of the plant, a new source would require 79
to 380 kw/mgd (1896 to 9120 kwh/mgd) discharged. These estimates
may be reduced if a number of plants opt for treatment practices
with lower power requirements such as irrigation or a combination
of anaerobic digestion and stabilization lagoons.
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SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION
OF THE BEST PRACTICAELE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
(LEVEL I EFFLUENT LIMITATIONS GUIDELINES)
Introduction
The effluent limitations which must be achieved July 1, 1977 are
to specify the degree of effluent reduction attainable through
the application of the "Best Practicable Control Technology
Currently Available", The Environmental Protection Agency has
defined the best practicable control technology currently
available as follows.
Best Practicable Control Technology Currently Available is
generally based upon the average of the best existing performance
by plants of various sizes, ages and unit processes within the
industrial category and/or subcategory. This average is not
based upon the entire range of plants within the dairy products
processing industry, but based upon performance levels achieved
by exemplary plants.
Consideration must also be given to:
1. The total cost of application of technology in relation
to the effluent reduction benefits to be achieved from
such application;
2. the size and age of equipment and facilities involved;
3. the processes employed;
14. the engineering aspects of the application of various types
of control techniques;
5. process changes;
6. non-wate^ quality environmental impact (including
energy requirements.
Also, Best Practicable Control Technology Currently Available
emphasizes treatment facilities at the end of a manufacturing
process but includes the control technologies within the process
itself when the latter are considered to be normal practice
within an industry.
A further consideration is the degree of economic and engineering
reliability which must be established for the technology to be
"currently available." As a result of demonstration projects,
pilot plants and general use, there must exist a high degree of
confidence in the engineering and economic practicability of the
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technology at the time of commencement of construction or
installation of the control facilities."
Effluent Reduction Attainable Through the Application of
The Best Practicable Control Technology Currently. Available
Based upon the information contained in Sections III through
Section IX of this report, and the results that are attained by
the better plants, it has been estimated that the degree of BOD5
reduction attainable through the application of the best
practicable control technology currently available in each
industry subcategory is as indicated in Table 21,
Suspended Solids
End-of-pipe biological treatment is primarily designed for
removal of BOD5, but it is generally effective in reducing the
level of suspended solids. Such is the case with dairy products
waste waters . The level of suspended solids in a treated
effluent is a result of the combined effect of the concentration
and nature of the suspended solids in the raw waste and the
settling characteristics of the biological sludge generated in
the treatment facility. In general, it is expected that the
concentration of suspended solids in the effluent will be equal
to or less than that of the BOD5. However, the somewhat poor
settling qualities of treated effluents from dairy products
processing is well documented, and this is reflected in the
values in Table 21. While the suspended solids levels in raw
waste waters were found to be approximately 40% of those of BOD5,
the guidelines limitations for suspended solids are higher than
those for BOD5.
Identification of Best Practicable Control Technology
The suggested effluent limitations are currently being achieved
by a number of "exemplary" plants in the industry. Other plants
can acheive them by implementing some or all of the following
waste control measures:
(a) In-Plant Control
1. Establishment of a plant management improvement program, as
described in detail in Section VII. Such a plan would cover
adoption of water conservation practices, installation of waste
monitoring equipment, improvement of plant maintenance,
improvement of production scheduling practices, quality control
improvement, finding alternate uses for products currently wasted
to drain, and improvement in housekeeping and product handling
practices.
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Specific attention should be given to recovery and use of whey
and other by-products rather than discharge to the treatment
system.
2. Improving plant equipment as described specifically under
"Standard Equipment Improvement Recommendations", items 1 through
13, in Section VII.
(b) End-of-Pipe Control
1. For large plants, installation of a biological treatment
system (activated sludge, trickling filter, or aerated lagoon),
designed generally in accordance with the suggested parameters
set forth in Section VII and operated under careful management.
2. For small plants, installation of an anaerobic digestion -
stabilization lagoon system in accordance with suggested
parameters set forth in Section VII.
3. Where land is available, irrigating the waste water by spray
or ridge and furrow, if this can be done economically and
satisfactorily. This option is of limited feasibility for the
very large plant.
5§tionale E2?. Selection Of Best Practicable Control Technology
Currently Available
In view of the biodegradable nature of dairy processing wastes
and the current limited development of chemical-physical
treatment for organic wastes, conventional biological treatment
was considered to be the logical choice for end-of-pipe
technology. Evaluation of the application of biological
treatment within the dairy processing industry indicated that a
variety of systems (i.e., activated sludge and its variations,
trickling filters, or aerated lagoons) were capable of producing
high quality effluents consistent with those generally expected
from efficient "secondary treatment". This was true even for
those subcategories beset by the greatest problems of waste
concentration, waste volume and waste treatability. Accordingly,
technical feasibility indicated that effluent guidelines should
be in keeping with reductions attained by the better biological
treatment systems within the industry.
Late in the guidelines development period the issue of economic
impact on small plants arose. It was noted that the economics of
size associated with any single treatment approach (e.g.,
activated sludge) resulted in much higher "per unit of production
treatment costs" for small plants, and that the financial status
of small plants in general was poor. Economic analysis indicated
that the burden imposed by such high treatment costs would force
closure of many small plants. To ameliorate this effect,
guidelines based on a lesser degree of reduction attained by a
relatively low-cost system (anaerobic digestion followed by
stabilization lagoons) are applied to plants within the size
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ranges in which severe economic impact was expected. While no
field data was obtained on performance of such a system during
the course of the dairy technical study, information in the
literature and field data obtained by EPA in other technical
studies on wastes of a similar nature (i.e., high BOD5 and
suspended solids) indicate that compliance with the guidelines is
readily attainable using the design criteria specified in Section
VII.
Since the effluent discharged from a treatment facility is
dependent to some degree on the influent hydraulic and organic
load, some consideration must be given to in-plant control for
development of effluent guidelines. In-plant controls
incorporated into the development of best practicable control
technology guidelines have been limited to those housekeeping and
management practices (e.g., automatic shut-off valves on hoses
and spill control) that materially reduce hydraulic and organic
loads but do not require extensive plant modification or large
capital investment.
The effluent limitations values contained in Table 27 are based
on discharges expected from application of the appropriate end-
of-pipe treatment to the raw waste from a well-run dairy products
processing operation.
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Table 27
Effluent Reduction Attainable Through Application
of Best Practicable Control Technology Currently
Available
Effluent in kg/kkg of BOD5_
Received or Processed
Subcategory/Segment
Receiving Stations
Small
Other
Fluid Products
Small
Other
Cultured Products
Small
Other
Butter
Small
Other
Cottage Cheese
Small
Other
Natural Cheese
Small
Other
Ice Cream Mix
Small
Other
Ice Cream
Small
Other
Condensed Milk
Small
Other
Dry Milk
Small
Other
Condensed Whey
Small
Other
Dry Whey
Small
Other
BOD5
0.313
0.190
2.250
1.350
2.250
1.350
0.913
0.550
4.463
2.680
0.488
0.290
1.463
0.880
3.063
1.840
2.30
1.380
1.088
0.650
0.650
0.40
0.650
0.40
TSS
0.469
0.285
3.375
2.025
3.375
2.025
1.369
0.825
6.694
4.020
0.731
0.435
2.194
1.320
4.594
2.760
3.450
2.070
1.638
0.975
0.975
0.60
0.975
0.60
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SECTION X
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF THE BEST
AVAILABLE CONTROL TECHNOLOGY ECONOMICALLY ACHIEVABLE
Introduction
The effluent limitations which must be achieved by July 1, 1983
are to specify the degree of effluent reduction attainable
through the application of the "Best Available Control Technology
Economically Achievable" The Environmental Protection Agency has
defined this level of in the following terms:
"This level of technology is not based upon an average of the
best performances within an industrial category, but is to be
determined by identifying the very best control and treatment
technology employed by a specific point source whin the
industrial category or subcategory; where a technology is readily
transferable from one industry or process to another, such
technology may be identified as applicable. A specific finding
must be made as to the availability of control measures and
practices to eliminate the discharge of pollutants, taking into
account the cost of such elimination, and:
1. the age of equipment and facilities involved;
2. the process employed;
3. the engineering aspects of the application of various
types of control techniques;
4. process changes;
5. cost of achieving the effluent reduction resulting
from application of technology;
$ 6. non-water quality environmental impact (including
energy requirements).
In contrast to the best practicable control technology currently
available, the best available control technology economically
achievable assesses the availability in all cases of in-process
controls as well as control or additional treatment techniques
employed at the end of a production process. In-process control
options available which should be considered in establishing
control and treatment technology include, but need not be limited
to, the following:
1. Alternative Water Uses
2. Water Conservation
3. Waste Stream Segregation
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4. Water Reuse
5. Cascading.Water Uses
6. By-Product Recovery
7. Reuse of Waste Water Constituent
8. Waste Treatment
9. Good Housekeeping
10. Preventive Maintenance
11. Quality Control (raw material, product, effluent)
12. Monitoring and Alarm Systems
Those plant processes and control technologies which at the pilot
plant, semi-works, or other level, have demonstrated both
technological performances and economic viability at a level
sufficient to reasonably justify investing in such facilities may
be considered in assessing technology. Best available technology
control economically achievable is the highest degree of control
technology that has been achieved or has been demonstrated to be
capable of being designed for plant scale operation up to and
including "no discharge" of pollutants. Although economic
factors are considered in this development, the costs for this
level of control is intended to be the top-of-the-line of current
technology subject to limitations imposed by economic and
engineering f eas ibil ity . However , it may be characterized by
some technical risk with respect to performance and with respect
to certainty of costs* Therefore, attainment of this technology
may necessitate some industrially sponsored development worlc
prior to its application.
Effluent Reduction Attainable Through the Application of the Best
AZsliiabi6. Control Technology Economically Achievable
BOD5
Based on the information contained in Section VII and the data
base of this report, it has been estimated that the degree of
effluent reduction attainable through the application of the best
available technology economically achievable in each industry
subcategory is as indicated in Table 28. The BOD5 loads are the
suggested monthly average effluent limitations guidelines to be
met by July 1, 1983.
Suspended Solids
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Table 28
Effluent Reduction Attainable Through Application
of Best Available Control Technology Economically
Achievable
Effluent in kg/kkg of BOD£
Received or Processed
_Subcategory/Segment
Receiving Stations
Small
Other
Fluid Products
Small
Other
Cultured Products
Small
Other
Butter
Small
Other
Cottage Cheese
Small
Other
Natural Cheese
Small
Other
Ice Cream Mix
Small
Other
Ice Cream
Small
Other
Condensed Milk
Small
Other
Dry Milk
Small
Other
Condensed Whey
Small
Other
Dry Whey
Small
Other
BOD5
0.075
0.050
0.550
0.370
0.550
0.370
0.125
0.080
1.113
0.740
0.125
0.080
0.363
0.240
0.70
0.470
0.575
0.380
0.275
0.180
0.163
0.110
0.163
0.110
TSS
0.094
0.063
0.688
0.463
0.688
0.463
0.156
0.10
1.391
0.925
0.156
0.10
0.454
0.30
0.875
0.588
0.719
0.475
0.344
0.225
0.204
0.138
0.204
0.138
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Based on the s ame analy se s and rationale de scri bed under
"Suspended Solids" in Section IX of this report, and limited
dairy industry data on sand filtration, it is suggested that the
effluent limitation guidelines for suspended solids be as shown
in Table 28.
Identification of Best Available Control Technology Economically
Achievable
The suggested raw waste loads and end-of-pipe waste reduction are
currently being achieved by a few "exemplary" plants in the
industry. Other plants can achieve them by implementing some or
all of the following waste control measures:
(a) In-Plant Control
1. Establishment of a plant management improvement program, as
described in Section VII. Such a plan would cover a water use
conservation program, installation of waste monitoring equipment,
improvement of plant maintenance, improvement of production
scheduling practices, quality control improvement, finding
aIternate uses for products currently wasted to drain, and
improvement in product handling practices,
2. Improving plant equipment as described specifically urider
"Standard Equipment Improvement Recommendations", items 1 through
13, in Section VII.
3. Improving plant equipment as described specifically under
"New Concepts for Equipment Improvement" items 1 to 8, in Section
VII.
U. Applying process improvements, as described specifically
under "Waste Management Through Process Improvements". Items 3
and 4 are included only as possible approaches to meeting
guidelines limitations without installation of end-of-pipe
treatment improvements. The economics of individual cases will
determine whether or not this is the best approach to compliance.
(b) End-of-Pipe Control
1. Installation of a biological treatment system (activated
sludge, trickling filter, or aerated lagoon) designed generally
in accordance with the suggested parameters set forth in Section
VIII, and operated under good managmement.
2. Installation of
adequate capacity.
a sand filter or other polishing steps of
3. Where land is available, irrigating the waste water by spray
or ridge and furrow, if this can be done economically and
satisfactorily.
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E^tionale £Qr Selection of Best Available Control Technology
Economically Achievable
The effluent limitation values for best available control
technology economically achievable have been based on the further
waste discharge reduction attainable by adding an efficient
polishing operation (e.g., sand filtration) to the treatment
facilities of a plant complying with best practicable control
technology limitations. The feasibility of the potential
alternative for attaining the specified limitation (through in-
plant modifications detailed in Section VII) is dependent on the
cost of in-plant controls, the cost of additional waste
treatment, the value of recovered materials, and other factors
that must be evaluated on a case-by-case basis.
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SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
Introduction
In addition to guidelines reflecting the best practicable
control technology currently available and the best available
control technology economically achievable, applicable to
existing point source discharges July 1, 1977 and July 1, 1983
respectively, the Act requires that performance standards be
established for "new sources." The term "new source" is defined
in the Act to mean "any source, the construction of which is
commenced after the publication of proposed regulations
prescribing a standard of performance."
The Environmental Protection Agency has defined the
appropriate technology in the following terms: "The technology
shall be evaluated by adding to the consideration underlying the
identification of the best available control technology
economically achievable a determination of what higher levels of
pollution control are available through the use of improved
production processes and/or treatment techniques. Thus, in
addition to considering the best in-plant and end-of-process
control technology, the technology is to be based upon an
analysis of how the level of effluent may be reduced by changing
the production process itself. Alternative processes, operating
methods or other alternatives must be considered. However, the
end result of the analysis will be to identify effluent standards
which reflect levels of control achievable through the use of
improved production processes as well as control technology,
rather than prescribing a particular type of process or
technology which must be employed. A further determination which
must be made for the technology is whether a standard permitting
no discharge of pollutants is practicable."
At least the following factors should be considered with
respect to production processes which are to be analyzed in
assessing the technology:
1. the type of process employed and process changes
2. operating methods
3. batch as opposed to continuous operations
4. use of alternative raw materials and mixes of raw
materials
5. use of dry rather than wet processes (including
substitution of recoverable solvents for water)
6. recovery of pollutants as by-products
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Effluent Reduction Attainable. in_New_Sources
Because of the large number of specific improvements in
management practices and design of equipment, processes and
systems that have some potential of development for application
in new sources, it is not possible to determine, within
reasonable accuracy, the potential waste reduction achievable in
such cases. However, the implementation of many or all of the
in^plant and end-of-pipe controls described in Section VII should
enable new sources to achieve the waste load discharges defined
in Section X,
The short lead time for application of new source performance
standards (less than a year versus approximately 3 and 9 years
for other guidelines) affords little opportunity to engage in
extensive development and testing of new procedures. The single
justification that could be made for mere restrictive limitations
for new sources than for existing sources would be one of
relative economics of installation in new plants versus
modification in existing plants. There is no data to indicate
that economics of new technology in dairy products processing is
significantly weighted in favor of new plants.
The attainment of zero discharge of pollutants does not
appear to be feasible for dairy product plants other than those
with suitable land readily available for irrigation. Serious
problems of sanitation are associated with complete recycle of
waste waters and the expenses associated with the complex
treatment system that would permit complete recycle (see Figure
18) are excessive.
In view of the foregoing, it is recommended that the effluent
limitations for all new sources be the same as those for best
available control technology economically achievable for larger
plant found in Section X.
No distinction is recommended for the smaller plant. With
minimization of raw waste loads (both hydraulic and organic)
through in-plant control (a necessity for economic viability of
smaller plants) and application of end-of-pipe treatment
suggested in Section X, the smaller plant should be able to meet
the recommended limitations.
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ACKNOWLEDGEMENTS
The Environmental Protection Agency wishes to acknowledge the
contributions to this project by A. T. Kearney, Inc., Chicago,
Illinois. Messrs. David Asper, David Dajani and Ronald L.
Orchard, ably assisted by their consultant Dr. W. James Harper of
Ohio State University, conducted the technical study and drafted
the initial report on which this document is based. Mr. Joseph
H. Greenberg served as Project officer.
Appreciation is extended to the many people and companies in
the dairy products processing industry who cooperated in
providing information and data and in making a number of their
plants available for inspection and sampling. Special
recognition is due the Task Force on Environmental Problems of
the Dairy Industry Committee for their role in facilitating
contact with representative segements of the industry and many
other contributions.
Indebtedness to those in the Environmental Protection Agency
who assisted in the project from inception of the study through
preparation and review of the report is acknowledged. Especially
deserving recognition are: Max Cochrane, Ernst Hall, Frances
Hansborough, Gilbert Jackson, Ray McDevitt, Ronald McSwinney,
Acquanetta McNeal, Walter Muller, Judith Nelson, John Riley, Jaye
Swanson, George Webster, and Ms. Bobby Wortman.
149
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-------
SECTION XIII
REFERENCES
1. Standard Industrial Classification Manual. Executive
Office of the President, Bureau of the Budget, 1967.
2- Dairy Effluents. Report of the Dairy Effluents Sub-
Committee of the Milk and Milk Products Technical
Advisory Committee; Ministry of Agriculture, Fisheries
and Food, Scottish Home and Health Department; Her
Majesty's Stationery Office, London, 1969.
3• Dairy Food Plant Wastes and Waste Treatment Practices.
A "State-of-the-Art" Study by W. James Harper and J. L.
Blaisdell for the Water Quality Office of the Environ-
ment Protection Agency, 1971.
**• Industrial Wastes - Dairy Industry. H. A. Trebler and
H. G. Harding, Ind. Eng. Chem, 39: 608, 1947.
5. Manual for Milk Plant Operators. Milk Industry Founda-
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6• Disposal and Treatment of Dairy Haste Waters. G. WaizhoIz,
International Dairy Federation Annual Bulletin (2) 1-57 1964.
7- Effluent Treatment and Disposal. M. Muers. Dairy Industry
(England) 33 (11) 747-751. 1968.
8« The Control of Dairy Effluent. L. Royal. Milk Industry
(England) 55: (4) 36-41? 1964.
9• Recent Developments in the Design of Small Milk Haste
Disposal Plants. J. P. Horton and H. S. Trebler.
Proc. 8th Ind. Waste Conf., Purdue Univ., 32-45, 1953.
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E. F. Eldridge, Mich. Engng. Exp. Sta., Bull.272, 1936.
11. Proportional Sampling of Dairy Haste Water. H.M.J. Scheltinga,
Pollution figures related to production. 17th Int. Dairy
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M. H. Askew, and J. H. Benton. Proc. 25th Ind. Haste Conf.,
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14. Dairy Waste Treatment. R. R. Kountz, J. Milk Fd. Technol.,
15. Some Consider;ations on_Waste_-Waters from Dairies^ and
151
-------
Their Purification. F. Cantinieaux, Bull. mens. Cent.
Beige Etude Docum. Eaux, No. 24, 103-109. 1954.
16. Air Diffusion in the. Treatment of Industrial Wastes.
G. E. Hauer, Proc. 9th Ind. Waste Conf., Purdue lUniv.,
60-63. 1954.
17.
^ Treatment by Activated Sludge. P. M. Thayer,
Wat. Sewage Wks.7~100:(1) 34. 1953.
18. Review of Cases Involving Dairy Effluent for the Period
Qct2feerjL-1967_-_gctgber_1.968. H. Werner and E. K. Lytken
Bilag.'til 28. arsberetningT 47-54. 1968.
19• Trickling Filters Successfully Treat Milk Wastes.
P. E. Morgan and E. R. Baumann, Proc. Amer. Soc,
Civ. Engrs., 83:SA4, Pap. No. 1336, 1-35. 1957.
20. Dairy Wastes Disposal by Ridge and Furrow Irrigation.
F.H. Schraufnagel. Proc. 12th Ind. Waste Conf., ~
Purdue Univ., 28-49. 1957.
21. Waste Treatment Facilities of the Belle Center
Creamery and Cheese Company. D. G. Neill. Proc. 4th
Ind. Waste Conf,, Purdue Univ., 45-53. 1948.
22. Milk Waste Treatment by Aeration. F. J, McKee.
Sewage Ind. Wastes,"22:1041-1046. 1950.
23. Spray Irrigation of Dairy Wastes. G. w. Lawton,
G. Breska, L. E. Engelbert, G, A. Rohlich and
N. Porges. Sewage Ind. Wastes 31:923-933. 1959.
24• Milk Plant Waste Disposal. W. E. Standeven. 39th
Ann. Rept., N.Y. State Assn. Milk and Food San., III.
1965.
25. Food Dehydration Wastes. A study of wastes from the
dehydration of skim milk, raw and fermented whey,
potatoes, beets, rutabagas, and hominy. F. E. DeMartini,
W. A. Moore, and G. E. Terhoeven. Publ. Hlth. Rep.,
Wash., Suppl. No. 191, 1-40. 1946.
26. Disposal of Food Processing Wastes by Spray Irrigation.
N.~H. San born. Sewage Ind. Wastes, 25:1034-1043. 1953.
152
-------
27. The Occurrence of Tubercule Bacilli in Drain Water
of Slaughter Houses, Dairies, and Rendering.Plants.
M. J. Christiansen and A. Jepsen. Maanedsky,
Dyrloeg., 57: (6) 173-193. 1945.
28. The Cost of Milk Haste Treatment. P. E. Morgan.
Am. Milk Rev., 19: (6730, 82, 84, 86 and 101-102.
1957.
29 • Methods and Results of Activated Sludge Treatment
of Dairy Wastes. S. D. Montagna. Surveyor, 97:117.
T940.
30. Aeration of Milk Wastes. W. A. Hasfurther and
C.W. Klassen. Proc. 5th Ind. Waste conf.,
Purdue Univ., 72, 424-430. 1949.
31• Some Experiences in the Disposal of Milk Wastes.
O.K. Silvester. J. Soc. Dairy Technol., 12:228-231.
1959.
32. Two-thousand Town Treats Twenty-thousand Waste.
0. E. Grewis and C. A. Burkett. Wat. Wastes Engng.,
3: (6)54-57. 1966.
33. Water Pollution by Finnish,Dairies. M. Sarkka,
J. Nordlund, M. Pankakoski, and M. Heikonen.
18th Int. Dairy Congr., I-E, A. 1.2 11. 1970.
34. Properties of Waste Caters from Butter Factories
and Processes for Their_Purification. S. S. Gauchman,
Vodos.~Sanit.~Tekh., 15: (1)50. 1940.
35. A Study of Milk Waste Treatment. B. F. Hatch and
J. H. Bass. 13th Annual Report, Ohio Conf. on
Sewage Treatment, 50-91. 1939.
36. Analysis of Waste Waters from Dairy and Cheese
Plants on the Basis of_Existing Literature.
M. Schweizer. Molkereizeitung, 9:254 and
256-257. 1968.
37. Dairy Waste Disposal by Spray Irrigation.
F. J. McKee. sewage'lnd. Wastes, 29: (2)157-164.
1954.
38• Investigations on Irrigation with Dairy Waste
Water. K. Wallgren, H. Leesment, and F. Magnus son.
Meddn. Svenska Mejeriern. Riksforen., 85: 20. 1967.
153
-------
39• The_.prQbJ.em_o£ Waste Disposal. An analysis of systems
used by selected dairy plants. M. E. Anderson and
H. A. Morris. Mfd. Milk Prod. J., 57:(8)8-10, 12,
(9)30-32, (10)12-13. 1966.
40. How can Plant Losses be Determined? D. E. Bloodgood
and R. A* Canham. Froc. 3rd Ind. Waste Conf.,
Purdue Urtiv., 293-309. 1947.
41• Milk Wastes in Sewage Sludge Digestion Tanks.
D. P. Backmeyer. Proc. 5th Ind. Haste Conf.,
Purdue Univ., 411-417. 194?.
42. Milk Waste Treatment on an Experimental Trickling
Filter. E. F. Gloyna. Water Sewage Works. J., 97;
(11) 473-478. 1950.
43• The Quantity and Composition of Dairy Waste Water
at a Dairy Plant* T. Bergman, F* Magnusson and
A. Berglof. Meddn Svenska Mejeriern. Riksforen, 86.
1966.
44. Glucose Dissappearance in Biological Treatment Systems.
J. S. Jeris and R. R. Cardenas. Appl. Microbiol-,
14: (6)857-864. 1966.
45. Monitoring Waste Discharge;, a New Tool for Plant
Management. R. R. zall. Dissertation, Cornell Univ.,
1968.
46. Dairy Factory Effluent Treatment by a .Trickling Filter.
J. S. Fraser. Aust.~J. Dairy Technol., 23: (2)104-106.
1968.
47• Dairy_ Waste-Saving and Treatment Guide. Dairy sanitation
Engineers Committee of the Pennsylvania Association of
Milk Dealers, Inc. in cooperation with Pennsylvania
Sanitary Water Board, 1948.
48• Industrial Waste Guide to the Milk Processing Industry.
U. S. Department of Health, Education and welfare.
Public Health Service Publication No. 298, 1959,
49. An Interpretation of the BODS Test in Terms of Endogenous
Respiration of Bacteria. S.R. Hoover, N. Porges and
L. Jasewicz. Sewage Ind. Wastes, 25:(10) 1163-1173.
1953.
50. CQntributions_to the Problem of Waste Waters in the
Milk Industry. ~H. Schulz-Falkenhain. Molk.-u. Kas.-Ztg.
6:1060-1062, 1116-1117, 1588-1590, 1610-1611, and
1671-1672. 1955.
51. Waste Control in_the_Dairy Plants. G. Walzholz.
154
-------
17th Int. Dairy Cong., E/F:785-792. 1966.
52• R.A.A.D. Test Installation. J. H. Rensink
Halfjaarl. Tijdschr. belg. stud, document.
Centre. Wat., No. 12, 44-46. 1963.
53. Experiments on the Biological Treatment of Dairy
Wastes. W. Furhoff. Vom Wasser,~28:430. 1961.
5<*. Oxygen Uptake of_ Face-try Effluents. K. Christensen.
Tsth Int. Dairy Cong., I-E7 A. 1.2, 14.
55• Methods for Estimating the_strength_of Dairy Effluents.
D. J."Reynolds, 17th Int. Dairy Congress, 5:773-780.
1966.
56. Effluent Problems in^Dairy Factories. G. Walholz, A.
Lembke, J. Gronau, H. Koster, and H. Schmidt. Keller
milkow. Forsch Ber., 20: (5) 415-532. 1968.
57. How_can_JPlant_Lgsses_Be_petermined? D.E. Bloodgood and
R. A. Canham. Proc. 3rd Ind. Waste Conf., Purdue Univ.
293-309. 1947.
5 8• The Cost of Clean Water. .Volume III - Industrial Waste
Prof lie No._ 9i DairJ.es., U.S. Department of the Interior,
Federal Water Pollution Control Administration, 1967.
59. Industrial Waste Recovery by Desalination Techniques.
U.S. Department of the Interior, Office of Saline
Water. Research and Development Progress Report
No. 581, October 1970.
60. Waste Prevention in the Dairy Industry. Report of
the Waste Disposal Task Committee of the Dairy
Industry Committee, February, 1950.
61- Treatment and Disposal of Dairy Waste Water; A_Reyiew.
W.J. Fisher. Review Acticle No. 147, Dairy Science
Abstract (England) 30 (11) 567-577. 1968.
62. Byproducts from Milk. B.H. Webb and E. O. Whittier
The AVI Publishing Company, 1970.
63. Water Use and Conservation in Food Processing Plants.
B. A. Twigg, Journal of Milk and Food Technology,
July 1967, 222-223.
78. Operation of a Milk-wastes Treatment Plant Employing a
Trickling Filter. J. W. Rugaber. Sewage Ind. wastes,
23: (11)^425-1428. 1951.
79. Some Experiences in the Disposal of_Milk Wastes.
O.K. Silvester. j7~Soc. Dairy Technology,~12: 2*28-231, 1959
155
-------
80. Preparation of Wastes for .Biological Filters. R.L. Smith
and Agneberg.~Publ. Wks.TN-Y.-, 94: (10)*170, 172, 174. 1963.
81• Treatment of Milk Washings by Addition of Coagulants,
Sedimentation, and Biological Filtration. B.A. Southgate.
Dairy Inds., 13: (3)235-240. 1948.
82. Dairy Waste Disposal. H.A, Trebler and H.G. Harding
Chem. Engng. Prog., 43: (5)255. 1947.
83. Treatment of Dairy Effluent by the Ferrobj.an-'-percolating
Method. G. Walzholz, H. Quest, A. Lembke and H.J. Fehlhaber.
j7"~Molkereizeitung, Hild. , 13: (14) 395-398. 1959.
84. New Developments in Treatment of Milk Hastes. L. F. waarick
FdT Inds., 12; (9)46-48 and 99?" 1940.
85. Treatment of Waste_Watera from Milk Products Factories.
A. B. Wheatland. Waste Treatment, Pergamon Press. 411-428.
1960.
86• High Rate Filters_Treat Creamery Wastes. M. A. Wilson
Sewage Wks. Engng., *17:309. 1946.
87• Treatment of Milk Wastes* N. D. Woolings, Munic. Util.,
90:(11~50, 52, 54,™12)"25-28, 30, 32, and 44-45. 1952.
88• Fundamentals of the Control and Treatment of Dairy Waste.
H. A. Trebler and H. G. Harding. Sewage Ind. Wastes
27:1369-1382. 1955.
89. Effluent Treatment Plant. Anonymous. Wat. and Wat. Engng.,
71:140. 1967.
90. The Bole o£ Contact Stabilization in the Treatment of
Indugtrial Waste Water and Sewage, a Progress.Report.
91• Dairy Waste Waters and Their Aerobic Treatment. S. Bunesova
and M. Dvorak. Vod. Hospod., "187466-467. 1968.
92. Some Considerations on Waste Waters from Dairies and Their
Purification. F. Cantineaux. Bull. mens. Cent. Beige
Etude Docum. Eaux. No. 24, 103-109. 1954.
93. An Industrial Waste Guide to the Milk Processing Industry*
Dairy Industry Committee, Sub-Committee on Dairy Waste
Disposal. Publ. Hlth. Engng. Astr., 32:(9)22-23. 1952.
94. Effect of Industrial Waste on Municipal Sewage Treatment.
E. F. Eldridge. Munic. Sanit., 10:491. 1939.
95. Milk Waste Treatment by the Mallory Process. .Waterworks
and Sewerage^ E. F. Eldridge. 88. (10)457-462. 194?.
156
-------
96*
9 7 .
98.
9 9 .
100.
101.
102.
103.
Estimation, of Coliform Bacteria on Dairy Wastes. J. Gillar
and D. Stelcova. Sb. Praci vyzk. Ust. Mlek., 118-129.
1963.
Experiments on the Biological Treatment of Dairy Hastes.
W.Furhoff. Vom~Wasser 28:430, ~1961.
BOD 5 Shock Load, G. Gault. J. Wat. Poll. Cont. Fed.,
32:903. 1960.
Dairy Industry . H , G . Harding . Ind . Engng . Chem . ,
491. 1952.
Aeration of Milk pastes. W. A. Hasfurther and C.W, Klassen.
Proc. 5th Ind. "waste Conf., Purdue Univ. 72, 424-430. 1949.
Successful Treatment of Dairy Waste by Aeration .
G. E. Hauer. Sewage Ind. Wastes, 24:1271-1277. 1952.
Satisfactory Purification of Dairy Wastes by the Activated
Sludge Method. A. Kannemeyer. Molk. -u Kas. -tg. , 9: (7)
187-190. 1958.
Dairy Waste Treatment Pilot Plant. R. R. Kountz. Proc. 8th
Ind. Waste Conf., Purdue UnivT, 382-386. 1953.
104. Performance of _ a Low-pressure Aeration Tank for Biochemical
Clarification _of Dairy Waste Waters. B.G. Mishukov.
Chem.~Abstr. , 62:127889. 19657
105. Methods and Results of Activated sludge Treatment of Dairy
Wastes . . S - D . Montagna . Surveyor . 97:117.
1940.
106. Treatment of Milk Trade Waste Water by the Activated-sludge
Process. K. Muller. Veroff , Inst. Siedungwasserwirt-
schaft. Hanover, No. 15, 35-143.
107. Waste Treatment Facilities of the Belle Center Creamery
and cheese Company. D.G. Neill. Proceed. 4th Ind.
Waste Conf,, Purdue Univ., 45-53. 1948.
108. Wa s te_Tr eatmen t . A. Pasveer. Proceedings of the 2nd
Symposium on Treatment of Waste Waters, Univ. of Durham,
117. 1959.
109. Plant for Biological Purification of Effluent in a Central
DaiEY." u- Paul. Wass.~Luft Betr. , 13: (3) 89-92. 1969.
110. Treatment of Dairy Waste by Aeration. R. M. Power.
sanitlk, 3:"(4f2-3. ~1955.~
111. Demonstration R.A.A.D. Purification Plant for Waste
157
-------
112.
113.
114.
115.
116.
117.
118.
119.
120.
121.
122.
123.
124.
125.
Water3 at Nutricia Ltd. ^__Zoetermeer. Ala. Zuivelb.
J. H. A. SchaafsmaT 50:306-309, and 330-332. "1957.
The Treatment: of Haste Waters at a Condensed Milk Plant.
L.F.~Schua. Wasserwirtschaft, Stuttg,, 56:370-372. 1966.
Non-clogging Foam-safe Aerators Lick Cheese-waste Problem.
K. L.~Schulze. Fd. Engng., 26: <9)~51-53. 19547
Proc. An. Soc._Civ. Engrs., K. L. Schulze.
Pap. No. 8477 1955."
81: SA4,
Activated Sludge Treatment of Milk Hastes. P.M. Thayer.
Sewage'lnd. Wastes,"23: (12)1537-1539. 1951.
Treatment of Dairy Waste Waters by the Activated Sludge
Method with Large Bubble Action Aeration. R. Thorn. 17th Int.
Dairy Congr.7 E.F: 709-714.™966.
Model Experiments for the Purification of Dairy Effluents
lY-Aeration. I. Tookos. ElelmT Iparr 19: (12)~ 367-371. 1965
Practical Aspects of Dairy Waste.Treatment. C.W. Watson.
Proc."15th Ind."waste Conf., Purdue Univ.7 81-89. 1960.
Purification of Dairy Waste in an Activated-sludge Plant
at the Rue Co-operative Dairy. H. Werner Beretn.
St. Forso-Ksmejeri,~V73: 1-22. 1969.
Activated-sludge Treatment of Some Organic Wastes.
A. B. Wheatland. Proc. 22 Ind. Waste Conf., Purdue Univ.,
983-1008. 1967.
The treatment of Effluents from the Milk Industry.
A.B. Wheatland7 Chemy Ind. 37: "1547-155T7 1967.
An Atlas of Activated Sludge Types. W. 0. Pipes. Report
on Grant No7 WP-00588-04 FWPCA, USDI, Civil Engineering
Department. Northwestern University, Evanston, Illinois.
1968.
Dairy Waste Disposal System.
Rev., 3"ll32. "19687
H. G. Harding. Amer, Dairy
Disposal of High Organic Content Wastes on Land.
R. H. Scott. J.~Wat. Poll, ContT Fed., 34:932-950. 1962.
The Development, Evaluation and Content of a Pilot Program
In Dairy Utiliza
In Dairy Utilization—Dairy Waste Disposal and Whey
Processing. W. S. Arbuckle and L. F, Blanton. Cooperative
Extension Service and Department of Dairy Science,
University of Maryland, 1-53. 1968.
126. Industrial Waste Stabilization Ponds in the United States.
158
-------
R. Porges. J. Wat. Poll. Cont. Fed.; 35:(4)456. 1963.
127. Waste Treatment by Stabilization Ponds. C. E. Carl.
Publ. Hlth. Engng. Abstr., 41: (10)35, 1961.
128. Sewage Stabilization Ponds in the Dakotas. Joint report
by North and South Dakota State Departments of Health,
and U.S. Department of Health, Education and Welfare,
Public Health Service. 1957.
129. Sewage Lagoons in the Rocky Mountains. D. P. Green
Journal of Milk and Food Technology. October, 1960.
130. Aerated Lagoons Treat Minnesota Town's Wastes. J. B. Neighbor
Civil Engineering - ASCE. December 1970.
131. Effect of Whey Wastes on Stabilization Ponds. T. E. Maloney,
H. F. Ludwig, J.A. Harmon and L. McClintock. J. Wat. Poll,
Cont. Fed., 32:1283-1299. 1960.
132. Monitoring Milk Plant Waste Effluent - A New Tool for
Plant Man
Plant Management. R.R. Zall and W. K. Jordan, Journal
of Milk and Food Technology, June, 1969.
133. Study of Wastes and Effluent Requirements of the
Dairy Industry, A. T. Kearney, Inc., Chicago, Illinois.
May, 1971.
134. The Treatment of Dairy_Plant Wastes. Prepared for the
Environmental Protection Agencies, Madison, Wisconsin,
March, 1973 Technology Transfer Seminar. Compiled by
K. S. Watson, Kraftco Corp.
135. Effect of Selected Factors on the Resporation and
Performance of a Model_pairv Activated Sludge System.
J. V. Chambers, The Ohio State University. Disser-
tation, 1972.
136. Estimating Costs and Manpower Requirements for
Conventipnal Waste_water_Treatment Facilities.
W. L. Patterson, R. F. Banker, Black & Veatch
Consulting Engineers. October, 1971*
137. Cost and Performance Estimates for Tertiary
Waste__water Treating. Processes. Robert Smith,
Walter F, McMichael. Robert A. Taft Water Research
Center. Report No. TWRC-9. Federal Water Pollution
138. Cost of Conventional and Advanced Treatment of
Waste waters. Robert Smith. Federal Water Pollution
Control Administration, Cincinnati, Ohio.
July, 1968.
159
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139. Waste water Reclamation in a Closed System* F. Besir.
Water 6 Sewage'works, 213 - 2197~July, 1971.
140. Reverse Osmosis for Municipal Water Supply* O. Peters
Shields. Water~~S Sewage Works7 64 - 70. January, 1972.
141. Industrial Waste Disposal. R. D. Ross, Edt. Van
Nostrand Reinhold Co., New York, 1968.
1 **2. Chemical Treatment of Sewage and Industrial Wastes.
Dr. William A. Parsons. National Lime Association,
Washington, D.C. 1965.
143. Industrial Pollution Control Handbook* H. F. Lund,
Edt. McGraw-Hill Book"co., New York, 1971.
144. Tertiary treatment. - Refining of Waste water.
V. M. Roach. General Filter Company, Ames, Iowa.
Bulletin No. 6703R1. June, 1968.
1^5. Upgrading Dairy Production Facilities to Control
Pollution. Prepared~for the Environmental protection"
Agencies, Madison, Wisconsin, March, 1973,
Technology Transfer Design Seminar. Prepared by
R. R. Zall and W. K. Jordan, Cornell University.
146. Water and Waste water Management in Daily Processing.
R. E. Carawan, V. A. Jones and A. P. Hansen, Department
of Food Science, North Carolina State University.
December, 1972.
147. Theories and practices of Industrial Waste Treatment
Nelson L. Nemetow. Addison-wesley Publishing Co., Inc.
Reading, Massachusetts. 1963.
148- Chemistry for Sanitary Engineers* Clair N. Sawyer,
perry L. McCarby. McGraw-Hill Book Co., New York,
1967.
149. Proceduraj. Manual for Evaluating the Performance of
Waste water Treatment Plants. Environmental Protection
Agency7~Washington, D.cT Contract No. 68-01-0107.
160
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SECTION XIV
GLOSSARY
Biochemical Oxygen
Demand
Churned
Buttermilk
Chemical Oxygen
Demand
Chlorine contact
(Or five-day BOD5). is the amount of
oxygen consumed by microorganisms to
assimilate organics in waste water over
a five day period at 20° C. BOD5 is
expressed in mg/1 (or ppm) and is the
most common yardstick at present to
measure pollutional strength in water.
The process whereby living organisms
in the presence of oxygen convert
the organic matter contained in waste-
water into a more stable or a mineral
form.
Byproduct resulting from the churning
of cream into butter. It is largely
defatted cream and its typical com-
position is 91)6 water. 4.5X lactose,
3.UX nitrogenous matter, 0.7Xash
and O.UX fat. churned or "true"
buttermilk is distinguished from cul-
tured buttermilk, which is a ferment-
ation product of skim milk. The latter
is sold in the retail market and re-
ferred to simply as "buttermilk0.
is the amount of oxygen provided by
potassium dichromate for the oxidation
of organics present in waste water. The
test is carried out in a heated flask
over a two hour period. One of the
chief limitations of the COD test is
its inability to differentiate between
biologically oxidizable and biologically
inert organic matter. Its major advan-
tage is the short time required for
evaluation when compared with the
five-day BOD test period. COD is ex-
pressed in mg.l or ppm.
A detention basin where chlorine is
diffused through the treated effluent
which is held a required time to provide
the necessary disinfection.
161
-------
Condensed
Cultured Products
Effluerit
Endogenous
Food to Microorganism
Ratio
The term "condensed" as used in
this report, applies to any liquid
product which has been concentrated
through removal of some of the water
it normally contains, resulting in
a product which is still in the
liquid or semi-liquid state. When
applied to milk, the term "condensed"
is used interchangeably with "evap-
oprate" to designate milk which has
been concentrated milk. Commercially,
however, the term "evaporate milk"
is commonly used to define unsweetened
concentrated milk.
Fermentation-type dairy products
manufactured by innoculating different
forms of milk with a bacterial culture
This designation includes yogurt,
cultured buttermilk, sour cream, and
cultured cream cheese, among other
products.
Waste containing water discharged
from a plant. Used synonymously
with "waste water" in this report.
An auto oxidation of cellular material
that takes plance in the absence of
assimilable organic material to fur-
nish energy required for the replace-
ment of worn-out components of proto-
plasm.
An aeration tank loading parameter.
Food may be expressed in pounds of
suspended solids, COD, or BOD5 added
per day to the aeration tank, and
microorganisms may be expressed as
mixed liquor suspended solids (MLSS)
or mized liquor volatile suspended
solids (MLVSS) in the aeration tank.
The flow (volume per unit time) applied
to the surface area of the clari-
fication or biological reactor units
(where applicable).
162
-------
Hydraulic
Loading
Influent
Ice Cream
Milk Equivalent
M. E?
Mixed Liquor
The flow (volume per unit time)
applied to the surface area of
the clarification or biological
reactor units (where applicable).
Waste water or other liquid - raw
or partially treated; flowing into
a reservoir, basin, treatment pro-
cess or treatment plant.
Applied in a general sense, this
term refers to any milk-based
product sold as frozen food.
Food regulatory agencies define
ice-cream in terms of composition,
to distinguish the product from
other frozen dessert-type products
containing less milk-fat or none at
all, such as sherbert, water ices
and mellorine.
Quantity of milk (in pounds) to
produce one pound of product. A
milk equivalent can be expressed
in terms of fat solids, non-fat
solids or total solids, and in
relation to standard whole milk
or milk as received from the farm:
the many definitions possible
through the above alternatives
has resulted in confusion and
inconsistent application of the
The most widely used milk equiva-
lents are those given by the U.S.
Department of Agriculture,
Statistical Bulletin No. 362
"Conversion Factors and Weights
and Measures for Agricultural
Commodies and Their Products."
A mixture of activated sludge and
waste water undergoing activated
sludge treatment in the aeration
tank.
A means of expressing the degree of
acidity or basicity of a solution,
defined as the logarithm of the
reciprocal of the hydrogen ion
concentration in gram equivalent per
liter of solution. Thus at normal
temperature a neutral solution such
as pure distilled water has a pH of
about 7, a tenth-normal solution of
163
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Raw Waste Load
Recirculation
Sanitary Sewer
System
skim Milk
siguqhings
hydrochloric acid has a pH near 1
and a normal solution of strong
alkali such as sodium hydroxide
has a pH of nearly 14.
Milk as received from the farm or
of standardized composition that
has not been pasteurized.
Numerical value of any waste
parameter that defines the
characteristics of a plant
effluent as it leaves the plant,
before it is treated in any way.
The rate of return of part of the
effluent from a treatment process
to the incoming flow.
A sewer intended to carry waste
water from home, businesses, and
industries. Storm water runoff
sometimes is collected and trans-
ported in a separate system of pipes,
In common uaage, skim milk
(also designated non-fat,
defatted, or "fat-free" milk)
from which that fat has been
separated as completely as
commercially practicable.
The maximum fat content is
normally established by law
and is typically 0.1X in
the United States. There is
also a common but not univer-
sal requirement that non-fat
milk contain a minimum
quantity of milk solids other
than fat, typically 8.25*.
In many states the meaning
of the term skim milk is
broadened to include milk
that contains less fat
that the legal minimum for
whole milk, such as the low-
fat sold in the retail
market. The term skim milk
used in this study refers
to non-fat milk.
Trickling filter slimes that
have been washed off the filter
media. They are generally quite
164
-------
Standard Manufacturing
Process
Suspended Solids
Waste
Waste Load
Waste Water
Whey
high in BOD5 and will degrade
effluent quality unless removed.
An operation or a series of
operations which is essential
to a process and/or which
produced a waste load that is
substantially different from
that of an alternate method
of performing the same
process. The concept was
developed in order to have
a flexible "building
block" means for charac-
terizing the waste from
any plant within an
industry.
Particles of solid matter in
suspension in the effluent
which can normally be removed
by settling or filtration.
Potentially polluting material
which is discharged or disposed
of from a plant directly to the
environment or to a treatment
facility which eliminates its
undesirable polluting effect.
Numerical value of any waste
parameter (such as BOD
content, etc.) that serves
to define the characteristics
of a plant effluent.
Waste-containing water discharged
from a plant. Used synonymously
with "effluent" in this report.
By-product in the manufacture of
cheese which remains after
separating the cheese curd from
the rest of the milk used in the
process. Whey resulting from
the manufacture of natural cheese
is termed "sweet whey" and its
composition is somewhat differ-
ent to "acid whey" resulting from
the manufacture of cottage cheese.
Typically, whey is composed of
93% water and 7% solids, including
5% lactose.
165
-------
Whole
- In its broad sense, the term whole
milk refers to milk of composition
such as produced by the cow. This
composition depends on many
factors and is seasonal with fat
content typically ranging between
3.5% and 4.0%. The term whole
milk is also used to designate
market milk whose fat content has
been standardized to conform to a
regulatory definition, typically
3.5%.
166
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METRIC UNITS
CONVERSION TABLE
MULTIPLY (ENGLISH UNITS)
ENGLISH UNIT
acre
acre - feet
British Thermal
Unit
British Thermal
Unit/pound
cubic feet/minute
cubic feet/second
cubic feet
cubic feet
cubic inches
degree Fahrenheit
feet
gallon
gallon/minute
horsepower
Inches
Inches of mercury
pounds
million gallons/day
mile
pound/square inch
(gauge)
square feet
square inches
tons (short)
yard
>BBitEVIATION
ac
ac ft
BTU
BTU/lb
cf m
cf s
cu ft
cu ft
cu in
°F
ft
gal
gpm
hp
in
in Hg
lb
mgd
mi
psig
sq ft
sq in
ton
yd
by TO OBTAIN
CONVERSION ABBREVIATION
0.405
1233.5
0.252
0.555
0.028
1.7
0.028
28.32
16.39
0.555(°F-32)*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
ha
cu m
kg cal
kg cal/kg
cu m/min
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
kn
(0.06805 psig +l)*atm
0.0929
6.452
0.907
0.9144
sq m
sq cm
kkg
METRIC UNIT
hectares
cubic meters
kilogram-calories
kilogram calories/
kilogram
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
killowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres
(absolute)
square meters
square centimeters
metric tons
(1000 kilograms)
meters
* Actual conversion* not a multiplier
*US. GOVERNMENT PRINTING OFFICE: 1974 582-412/21 1-3
1P7
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