EPA 440/1-73/012
      Development Document for
Proposed Effluent Limitations Guidelines
and New Source Performance Standards
               for the


   RED MEAT PROCESSING

            Segment of the
      Meat Product and Rendering
              Processing
        Point Source Category
   UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

              OCTOBER 1973

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                   Publication Notice






     This is a development document for proposed effluent




limitations guidelines and new source performance standards,




As such, this report is subject to changes resulting from




comments received during the period of public comments




of the proposed regulations.  This document in its final




form will be published at the time the regulations for




this industry are promulgated.

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                           DEVELOPMENT DOCUMENT

                                   for

                     EFFLUENT  LIMITATIONS  GUIDELINES

                                   and

                     NEW  SOURCE  PERFORMANCE STANDARDS




           RED MEAT  PROCESSING  SEGMENTS OF THE MEAT PRODUCTS

                         POINT  SOURCE CATEGORY
                              Russell  Train
                              Administrator

                             Robert  L.  Sansom
            Assistant Administrator for Air &  Water Programs
                               Allen  Cywin
                 Director,  Effluent  Guidelines Division

                             Jeffery  D.  Denit
                             Project  Officer
 1                             September 1973
--•is
                       Effluent Guidelines Division
                     Office of Air and Water Programs
                  U.  S. Environmental Protection Agency
                         Washington,  D.  C.  20460

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                                ABSTRACT


This document presents the findings of an extensive study  of  the  meat
packing  industry by the Environmental Protection Agency for the purpose
of developing effluent limitations guidelines, and Federal standards  of
performance  for  the industry, to implement Sections 304 and 306 of the
Federal Water Pollution Control Act Amendments of 1972 (the "Act") .

The segments of the meat packing industry included in the study were red
meat slaughterhouses, packinghouses.  Not included were plants that only
process meat  but  do  no  on-site  slaughtering,  rendering  operations
carried  out  off  the site of the packing plant, and all poultry (white
meat)  processing plants.

Effluent limitations guidelines are set forth for the degree of effluent
reduction attainable through the application of  the  "Best  Practicable
Control   Technology  Currently  Available",  and  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"  set  forth  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 proposed recommendations require
the  best  biological  treatment  technology  currently  available   for
discharge  into  navigable  water  bodies  by  July 1, 1977, and for new
source  performance  standards.   This  technology  is  represented   by
anaerobic  plus aerated plus aerobic lagoons with efficient solid-liquid
separation, or their equivalent.  The recommendation for July  1,  1983,
is  for  the best biological, chemical and/or physical treatment and in-
plant  controls.   In  this  instance,  efficient  biological  treat  is
complemented  by water conservation practices, improved nutrient removal
concepts, and water filtration types of final treatment.  When  suitable
land  is  available,  land  disposal  may  be  an  economical  option to
eliminate any direct discharge.  Recycle or reuse of effluents into  the
plant may offer an additional alternative in this regard.

Supportive  data  and rationale for development of the proposed effluent
limitations guidelines and standards of  performance  are  contained  in
this report.

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                                CONTENTS
                                                            Page
Section

   I.    CONCLUSIONS                                         -1

  II.    RECOMMENDATIONS                                     3

 III.    INTRODUCTION                                        5

              Purpose and Authority                          5

              Summary of Methods Used for Development of
              the Effluent Limitations Guidelines and
              Standards of Performance                       ^

              General Description of the Industry            9

              Process Description                            11

              Manufacturing Processes                        15

                   Stockyards and Pens                       15
                   Slaughtering                              15
                   Blood Processing                          18
                   Viscera Handling                          18
                   Cutting                                   19
                   Meat Processing                           20
                   Rendering                                 20
                   Materials Recovery                        21

              Production Classification                      23

              Anticipated Industry Growth                    23

  IV.    INDUSTRY CATEGORIZATION                             25

              Categorization                                 25

              Rationale for Categorization                   27

                   Waste Water Characteristics and           27
                   Treatability                              27
                   Final Products                            29
                   Primary Manufacturing Processes           30
                   Secondary Manufacturing Processes         30
                   Raw Materials                 ,            32
                   Size, Age, and Location                   33
                               ill

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Section                                                          Page

   V.    WATER USE AND WASTE CHARACTERIZATION                     35

              Waste Water Characteristics                         35

                   Raw Waste Characteristics                      35
                   Slaughterhouses                                36
                   Packinghouses                                  38
                   Discussion of Raw Wastes                       41

              Process Flow Diagrams                               44

              Water Use - Wasteload Relationships                 48

              Sources of Waste Water                              50

                   Animal Pens                                    50
                   Slaughtering                                   50
                   Meat Processing                                51
                   Secondary Manufacturing Processes              52
                   Cutting                                        53
                   Clean-Up                                       53

  VI.    SELECTION OF POLLUTANT  PARAMETERS                        55

              Selected Parameters                                 55

              Rationale for Selection  of  Identified Parameters   55

                   5-Cay Biochemical Oxygen  Demand               55
                   Chemical Oxygen Demand                        56
                   Suspended Solids                               56
                   Dissolved Solids                               57
                   Ammonia Nitrogen                                57
                   Kjeldahl Nitrogen                               58
                   Nitrates and  Nitrites                           58
                   Phosphorus                                      59
                   Chlorides                                       59

 VII.    CONTROL  AND  TREATMENT TECHNOLOGY                         61

              Summary                                             61

              In-Plant Control Techniques                         61

                   Pen Wastes                    '                  63
                   Blood Handling                                  63
                   Paunch                                          63
                   Viscera  Handling                                64
                   Troughs                                         64
                   Rendering                                       64


                                 iv

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Section                                                       Page

 VII.    CONTROL AND TREATMENT TECHNOLOGY  (Continued)

                   Hide Processing                              65
                   Scald Tank                                   65
                   Pickle and Curing Solutions                  65
                   Water Conservation Practices                 66
                   Clean^-Up Operations                          67

              In-Plant Primary Treatment                        68

                   Flow Equalization                            68
                   Screens                                      68
                   Catch Basins                                 70
                   Dissolved Air Flotation                      71

              Secondary Waste Water Treatment Systems           76

                   Anaerobic Processes                          77
                   Aerated Lagoons                              79
                   Aerobic Lagoons                              80
                   Activated Sludge                             83
                   Trickling Filter                             86
                   Rotating Biological Contactor                88
                   Performance of Various Secondary
                   Treatment Systems                            89

              Tertiary and Advanced Treatment                   91

                   Chemical Precipitation of Phosphorus         91
                   Sand Filter                                  93
                   Microscreen-Microstrainer                    95
                   Nitrification-Denitrification                96
                   Ammonia Stripping                            99
                   Spray/Flood Irrigation                      101
                   •Ion Exchange                                104
                   Carbon Adsorption                           107
                   Reverse Osmosis                             110
                   Electrodialysis                             111

VIII.    COST, ENERGY, AND NON-WATER QUALITY ASPECTS          115

              Summary                                          115
              "Typical" Plant                                  117
              Waste Water Treatment Systems                    121
              Treatment and Control Costs                      124

                   In-Plant Control Costs                      124
                   Secondary and Tertiary Treatment  Costs      125

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Section                                                            Page

VIII.    COST, ENERGY, AND NON-WATER QUALITY ASPECTS  (Continued)

                   Investment Costs Assumptions                     125
                   Annual Costs Assumptions                         128

              Energy Requirements                                   129

              Non-Water Pollution by Waste Water  Treatment Systems 130

                   Solid Wastes                                     130
                   Air Pollution                                    131
                   Noise                                            132

  IX.    EFFLUENT REDUCTION ATTAINABLE  THROUGH THE APPLICATION
         OF THE BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
         AVAILABLE—EFFLUENT LIMITATIONS GUIDELINES                133

              Introduction                                          133

              Effluent Reduction Attainable Through The Application
              of Best Pollution Control Technology Currently
              Available                                             134

              Identification of Best  Pollution  Control Technology
              Currently Available                                   134

              Rationale for the Selection of  Best Pollution
              Control Technology Currently Available               137

                   Age and Size of  Equipment  and Facilities        137
                   Total Cost  of Application  in  Relation to
                      Effluent Reduction Benefits                  138
                   Engineering Aspects  of Control Technique
                      Applications                                  138
                   Process Changes                                  141
                   Non-Water Quality  Environmental Impact          141

    X.    EFFLUENT REDUCTION ATTAINABLE  THROUGH THE APPLICATION
         OF THE  BEST  AVAILABLE TECHNOLOGY ECONOMICALLY
         ACHIEVABLE—EFFLUENT  LIMITATIONS GUIDELINES               143

              Introduction                                          143

              Effluent Reduction Attainable Through Application
              of the  Best Available Technology Economically
              Achievable                                            144

              Identification of the Best Available Technology
              Economically Achievable                              144
                                   vl

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Section                                                             Page

   X.    EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION
         OF THE BEST  AVAILABLE TECHNOLOGY ECONOMICALLY
         ACHIEVABLE—EFFLUENT LIMITATIONS GUIDELINES

              Rationale  for Selection of the Best Available
              Technology Economically Achievable                    148

                   Age and size of Equipment and Facilities         148
                   Total Cost of Application in Relation to
                      Effluent Reduction Benefits                   148
                   Engineering Aspects of Control Technique
                      Application                                   149
                   Process Changes                                  149
                   Non-Water Quality Impact                         150

  XI.    NEW SOURCE PERFORMANCE STANDARDS                           151

              Introduction                                          151

              Effluent Reduction Attainable for New Sources         152

              Identification of New Source Control Technology       153

              Rationale for Selection                                   154

 XII.    ACKNOWLEDGMENTS                                            155

XIII.    REFERENCES                                                  157

 XIV.    GLOSSARY                                                    161

         Metric Conversion Table                                        171
                                 vii

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                                FIGURES

Number                                                          Page

   1.    Process Flow in a Packing Plant                         13

   2.    Process Flow for Simple Slaughterhouse                  14

   3.    Waste Flow Diagram for a Packinghouse                   16

   H.    Categorization of Meat Packing Plants                   28

   5.    Operating and Waste Water Flow Chart for Simple
              and Complex Slaughterhouses                        37

   6.    Operating and Waste Water Flow Chart for Low- and
              High-Processing Packinghouses                      40

   7.    Typical Waste Water Treatment System Without
              Dissolved Air Flotation                            45

   8.    Typical Waste Water Treatment System Including
              Dissolved Air Flotation                            47

   9.    Separate Treatment of Grease-Bearing, Nongrease-
              Bearing and Manure-Bearing Waste Waters            47b

  10.    Effect of Water Use on Wasteload for Individual
              Plants                                             49

  11.    Suggested Meat Packing Industry Waste Reduction
              Program                                            62

  12.    Dissolved Air Flotation                                 73

  13.    Process Alternatives for Dissolved Air Flotation        74

  14,    Anaerobic Contact Process                               82

  15.    Activated Sludge Process                                84

  16.    Chemical Precipitation                                  92

  17.    Sand Filter System                                      93

  18.    Microscreen/Microstrainer                               95

  19.    Nitrification/Denitrification                           97
                                  viii

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                             FIGURES  Cont'd



Number                                                        Pa8e



  20.    Ammonia Stripping                                     10°



  21.    Spray/Flood Irrigation  System                        102



  22.    Ion Exchange                                          105



  23.    Carbon Adsorption                                     108



  24.    Reverse Osmosis                                       110



  25.    Electrodialysis                                       112
                                  ix

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                                 TABLES

Number                                                                Page

   1.    Commercial Slaughter in 48 States                             10

   2.    Summary of Plant and Raw Waste Characteristics
              for Simple Slaughterhouses                               39

   3.    Summary of Plant and Raw Waste Characteristics
              for Complex Slaughterhouses                              39

   4.    Summary of Plant and Raw Waste Characteristics
              for Low-Processing Packinghouses                         43

   5.    Summary of Plant and Raw Waste Characteristics
              for High-Processing Packinghouses                        43

   6.    Performance of Various Secondary Treatment
              Systems                                                  90

   7.    Average Total Waste Treatment Investment costs per
              Plant to Achieve a Given Level of Effluent Quality.     116

   8.    Estimated Total Investment Cost to the Industry to
              Achieve a Given Level of Effluent Quality from
              Present Level of Treatment                              119

   9.    Total Increase in Annual Cost of Waste Treatment             119

  10.    Waste Treatment Systems, Their Use and Effectiveness         120

  11.    In-Plant control Equipment Cost Estimates                    124

  12.    Secondary Waste Treatment System Costs                       126

  13.    Advanced Waste Treatment System Costs                        127

  14.    Recommended Effluent Limit Guidelines for
              July 1, 1977                                            135

  15.    Adjustments for Exceptions in Plant Subcategories            136

  16.    Recommended Effluent Limit Guidelines for
              July 1, 1983                                            145

  17.    Adjustments for Exception in All Plant Subcategories—
              1983                                                    146

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                               SECTION I

                              CONCLUSIONS
A  conclusion  of this study is that the meat packing industry comprises
four subcategories:

         Simple Slaughterhouses
         Complex Slaughterhouses
         Low-Processing Packinghouses
         High-Processing Packinghouses

The major criterion for the establishment of the categories was  the  5-
day  biochemical  oxygen  demand (BOD5) in the plant waste water.  Other
criteria were the primary  products  produced  and  the  secondary  (by-
product) processes employed.

The wastes from all subcategories are substantially organic in character
and are amenable to biological treatment

Discharge  limits  that  represent  the  average  of  the best treatment
systems in the industry for the four  subcategories  are  being  met  by
about  25  percent  of  the  plants  for which data are available; these
limits are recommended for 1977.  The same limits  are  recommended  for
new  sources  with  additional requirements for controlling nitrates and
phosphorus.  It is estimated that the costs of achieving these limits by
all plants within the industry is about $53 million.  These costs  would
increase  the  capital investment in the industry by about three percent
and would  equal  about  20  percent  of  the  industry's  1971  capital
investment.

For  1983, effluent limits were determined as the best achievable in the
industry for  5-day  biochemical  oxygen  demand   (BODS)  and  suspended
solids.   Limits  for Kjeldahl nitrogen, ammonia, nitrites and nitrates,
and phosphorus were established on the basis of transfer  of  technology
from  other  industries  or  of newly developing technology.  It is also
concluded that, where suitable and  adequate  land  is  available,  land
disposal  is  a economical option.  It is estimated that the costs above
those for 1977 for achieving the 1983 limits by all  plants  within  the
industry are about $107 million.  These costs would further increase the
capital investment in the industry by about six percent, and would equal
about 44 percent of the industry's 1971 capital investment.

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                               SECTION II

                            RECOMMENDATIONS


Guideline  recommendations for discharge to navigable waters for July 1,
1977, are based on  the  characteristics  of  well  operated  biological
treatment  plants.   The  guidelines for 5-day biochemical oxygen demand
(BOD5)  range, for example, from 0.08 kg/1000 kg live weight-killed (LWK)
for simple slaughterhouses to 0. 24 kg/1000 kg LWK for an  average  high-
processing  packinghouse.   Other  major parameters that are limited are
suspended  solids  and  grease,  total   Kjeldahl   nitrogen,   ammonia,
phosphorus, and nitrite-nitrate.

Recommended  New  Source  Standards  are the same as the 1977 guidelines
with additional requirements for controlling nitrates and phosphorus.

Guidelines recommended for 1983 are considerably  more  stringent.   For
example,  BOD5  limits  range  from  0.03  kg/1000  kg  LWK  for  simple
slaughterhouses to 0.09 kg/1000 kg LWK for  an  average  high-processing
packinghouse.   Limits are also placed on the other parameters mentioned
above,  with  particular  attention  to  the  ammonia  discharge.    The
suspended solids range from 0.05 to 0.12 kg/1000 kg LWK; grease is below
the  limits  of  detection  by  standard  analytical  methods; and total
Kjeldahl nitrogen, ammonia nitrogen, phosphorus, and nitrite-nitrate are
limited by the concentrations achievable by the technology  rather  than
by  a  relation  to  the  production level.  Recycle to land disposal or
reuse in-plant are viable alternatives for consideration.

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                              SECTION III

                              INTRODUCTION


                                _AND_AUTHORIT Y

Section 301(b)  of the Federal Water Pollution Control Act Amendments  of
1972  (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  methods,  or other alternatives, including, where
practicable, a standard permitting no discharge of pollutants.

Section 304(b)  of the Aci 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 conirol
technology currently available and  the  degree  of  effluent  reduction
attainable  through  the  application  of  the best available technology
economically achievable including treatment techniques, process and pro--
cedure innovations,  opeiation  methods  and  other  alternatives.   The
regulations  proposed  herein  set forth effluent limitations guidelines
pursuant to Section 304 (L) of the Act for the red meat  slaughtering  arid
packing plant subcategor^ within the meat products source category.

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(b)   (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  Administrator1s
intention  of  establishing, under Section  306, standards of performance
based upon best available  demonstrated  technology  applicable   to  new
sources  for  the  red  meat  slaughtering  and packing  plant subcategory

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within the meat products source category,  which was included in the list
published January 16, 1973.

        SUMMARYOF_METHODSUSEDFORDEVELOPMENT OF THE EFFLUENT
                                                  PERFORMANCE'"''


The  effluent  limitations  guidelines  and  standards  of   performance
proposed  herein  were  developed  in  the  following manner.  The point
source category was first studied for the purpose of determining whether
separate  limitations  and  standards  are  appropriate  for   different
segments  within  a  point  source  category.   This analysis included a
determination of whether  differences  in  raw  material  used,  product
produced,   manufacturing  process  employed,  age,  size,  waste  water
constituents, and other factors require development of separate effluent
limitations and standards for different segments  of  the  point  source
category.   The  raw  waste  characteristics  for each segment were then
identified.  This included an analysis of  (1) the source and  volume  of
water  used  in  the  process employed and the source of waste and waste
waters in the plant; and  (2)  the constituents  (including thermal) of all
waste waters including  potentially  hazardous  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 known range of control and treatment  technologies  existing  within
each  category  was  identified.   This  included identification of each
distinct control and treatment technology, including  an  identification
in  terms  of  the  amount  of  constituents  (including thermal) and the
chemical, physical, and biological characteristics of pollutants, and of
the effluent levels 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  was  also  identified.   In addition,  the nonwater
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   identified.     The   energy
requirements  of  each  of  the  control  and treatment technologies was
identified as well as the cost of the application of such technologies.

The information, as outlined above,  was  then  evaluated  in  order  to
determine  what  levels  of technology constituted the "best practicable
control technology  currently  available",   "best  available technology
economically  achievable"  and  the "best available demonstrated control
technology, processes, 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

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age of equipment and facilities  involved,  the  process  employed,  the
engineering  aspects  of  the  application  of  various types of control
techniques,  process  changes,  nonwater  quality  environmental  impact
(including energy requirements) and other factors.


The  data  for identification and analyses were derived from a number of
sources.  These sources included Refuse Act  Permit  Program  data,  EPA
research  information; data and information from the North Star Research
and Development Institute files and reports, a  voluntary  questionnaire
issued   through   the  American  Meat  Institute   (AMI),  the  National
Independent Meat Packers Association  (NIMPA), and  Western  States  Meat
Packers  Association  (WSMPA) ; qualified technical consultation; and site
visits and interviews at several meat packing plants and slaughterhouses
in various  areas  of  the  United  States.   Questionnaire  information
provided  about  80  percent  of  the  raw  data  used to categorize the
industry, to characterize the raw waste, and to assess the effectiveness
of various treatment systems.  Information from the USDA  was  primarily
product  and  production  data.  Data from the Refuse Act Permit Program
(RAPP) were of very limited value; they were used  primarily  to  verify
the types of treatment used by various plants and to assist in selecting
the  pollutant  parameters  listed  in  Section  VI.  Although data were
obtained for 104 plants, only 85 of the plants were  identifiable.   The
data  for identifiable plants were the only data used for categorization
and raw waste  characterization.   The  other  sources,  including  site
visits  and interviews, were used to fill in the information gaps and to
provide additional insight and understanding to develop the rationale in
categorization.

The  data  were  coded  and  stored  in  a  computer  for  analysis   in
categorizing the industry and characterizing the raw wastes.  Originally
the  data  were  listed as 81 numeric or non-numeric variables.  Numeric
values were available for the six raw waste variables  (see  Section  V) ,
and  for  kill,  flow, processed meat production, and amount of cutting.
The non^numeric variables described  the  various  methods  of  handling
blood, paunch, viscera, hair, hides, the types and methods of rendering,
and  the  sampling  procedure used to obtain waste water samples.  Where
appropriate, missing data were listed as a separate variable.  The first
attempt to categorize the industry was based on a correlation  analysis,
but  no  useful  pattern  or  correlation  was found encompassing the 81
variables and the 85 plants.

Based on  knowledge of the industry  and  the  results  of  the  initial
correlation  analysis,  some variables with a presumed equivalent effect
on raw waste were combined, and others with little or no effect  on  raw
waste  were eliminated.  This reduced the number of variables from 81 to
53.  This analytical process was repeated and the  number  of  variables
was  again  reduced,  this time from 53 to 26.  For example, animal type
was eliminated as a variable  because  no  significant  correlation  was

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found  between  it  and  raw  waste.  Also,  the blood handling processes
involving either blood water evaporation  or  whole  blood  drying  were
lumped  together as a single variable because the waste load from either
process is similar.

The first analysis did not result in any reasonable grouping  of  plants
by  raw waste load.  The second s^tep produced ten groups of plants—four
groups of slaughterhouses and  six  of  packinghouses.   However,  there
remained   some   overlap  of  BOD5  distribution  between  the  groups,
particularly for the six groups of packinghouses.   Additional  analysis
revealed  a positive correlation quantity of processed meat products for
packinghouses.  The six packinghouse groups could be  combined  to  form
two  distinct  subcategories  with  reasonably  distinctive  waste  load
distributions.   The  two  subcategories  are  called  low-  and   high-
processing packinghouses.  The distinction between them, as described in
detail  in  section  IV,  is  based  on  the  quantity  of production of
processed meat products relative to the quantity .of animals slaughtered.

To achieve a more consistent and useful grouping of slaughterhouses,  an
empirical  weighting  factor  was  assigned to each secondary processing
technique; this factor  reflected  the  relative  contribution  of  each
technique  to  the  raw  waste  load   (see  Section  IV).   Two distinct
subcategories of slaughterhouses were identified; one  had  plants  with
empirical  weighting  factors  adding up to less than U.O, and the other
included those plants totalling more than 4.0.  These two  subcategories
were termed simple and complex slaughterhouses.  The raw waste data were
then  statistically  analyzed  for  each  subcategory;  the  results are
presented in Section V.

The empircal weighting factors listed in Section IV were, in some cases,
calculated from raw data obtained from the sources  mentioned  above  or
from  published  information;  in  other  cases  they  were  based  upon
experience and judgment.  The credibility of the  weighting  factors  is
based on the fact that the numbers used are good predictors of raw waste
load  relative  to  in-plant  operations  and also to the fact that they
explain differences in  raw  waste  load  between  plants  in  the  same
subcategory but with different in-plant operations.

The  value  of  1.5  kg  BODS  per  1000 kg LWK  for hide processing, for
example, was obtained in two ways:  first, from  the raw waste data  from
two  hide  curing plants, and second,  from the difference between actual
and expected raw waste load from a  slaughterhouse  killing  about  1500
head per day, but processing about  7000 hides per day.  The value of 1.0
kg  BODS  per  1000 kg LWK for wet dumping of paunch was calculated from
data provided in reference 12.  Assumptions  were  made  that  the  BODS
waste load is caused by the loss of most of the  water-soluble portion of
paunch  contents; that 71 percent of the weight  of the  paunch is lost to
the sewer as liquid; that the BODS  of  the liquid is   28,240  mg/1;  and
that there are 50 kg of paunch contents per 1000 kg LWK.  Therefore, for
                                    8

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a  weight  of 454 kg (1000 pounds)  per head of cattle, the paunch factor
is calculated to be (18,240 x  10-6  x  50  x  0.71)   or  about  1.0  kq
BOD5/1000 kg LWK (1 Ib EOD5/1000 kg LWK).

The  value  of  1.2  kg  BOD5/1000 kg LWK for coagulating and separating
blood, with the blood water sewered, was calculated assuming 35 kg blood
per 1000 kg LWK.  The blood water was assumed to have a BOD5  of  40,000
mg/1  and  to  account  for 82.4% of the weight of the whole blood.  The
value of 2.0 kg BOD5 per  1000  kg  LWK  for  wet  and  low  temperature
rendering  was obtained by assuming 150 kg rendered material per 1000 kg
LWK, and a liquid effluent weight equal to 45 percent of the  weight  of
rendered  material.   The  BODS  of  the liquid was assumed to be 30,000
mg/1.  All remaining factors presented in Section  IV  under  "Secondary
Manufacturing Processes"--whole blood drying, dry rendering, and various
method   of   hair  and  viscera  processing—were  estimated  based  on
experience and  an  engineering  knowledge  of  the  processes  and  the
effluent characteristics involved.

All   references   used   in  developing  the  guidelines  for  effluent
limitations and standards of performance for new sources reported herein
are included in Section XIII of this document.

                  GENERAL_DESCRIPTION_OF_THE_INDUSTRY

Meat packing plants carry out the slaughtering and processing of cattle,
calves, hogs, and sheep for the preparation of  meat  products  and  by-
products  from  these  animals.   The plants in this industry range from
plants that carry out only one operation, such as slaughtering, to full-
line plants that not only slaughter, but also carry  out  processing  to
varying  degrees (manufacturing of meat products such as sausages, cured
hams,  smoked  products,  etc).   The  amount   of   processing   varies
considerably,  because  some process only a portion of their kill, while
others process not only their kill, but also the kill from other plants.
Most full-line plants   (packinghouses)  and  many  slaughterhouses  also
render  by-products;  edible  and inedible by-products are rendered from
edible fats and trimmings and from inedible materials, respectively.

Reportedly, there were 5991 meat slaughtering plants in  these  48  con-
tiguous  states  and  Hawaii  on  March  1, 1973. 1  Of these, 1364 were
federally inspected.  The industry produced about 37 billion  pounds  of
fresh,  canned,  cured,  smoked,  and  frozen  meat  products  per year.
Perhaps 85 percent of the plants in the industry are small plants  (local
meat lockers, etc. handling less than  43,000  kg  or  100,000  Ibs.  of
animals  per  day)   for  which  waste  load  data are almost universally
unavailable.  The remaining 15 percent of the plants account for by  far
the largest part—probably over 90 percent—of the production, and thus,
of  the waste load.  In 1966, about 70 percent of all waste water in the
meat packing industry went to municipal systems; at  that  time  it  was
projected  that,  by  1972,  80 percent would be discharged to municipal

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systems.  It was estimated that in 1962 65 percent of  the   total   waste
water  flow  from  all small plants in the U.S., discharged  to  municipal
systems; 2 the figure is undoubtedly higher today.
While the industry is spread over much of the  country,  the
Nebraska  and  Iowa  led  the  nation  in beef slaughter with
million head each in 1972. 1  Between them, these two   states
for  over  26  percent  of the beef production in the nation.
states making up the first ten in beef slaughter,  each with
million  head,  are  Texas,  California,  Kansas,  Colorado,
Illinois, Wisconsin, and Ohio.
states  of
nearly 4.7
 accounted
 The other
 over  one
Minnesota,
Iowa led in hog slaughter by  a  wide  margin,   slaughtering  nearly  21
million  animals  in  1971 for nearly  25 percent of the  national produc^
tion.  The second state, Illinois, slaughtered about   6.3   million;   the
rest  of the first ten include, in order, Minnesota, Pennsylvania,  Ohio,
Michigan, Indiana, Wisconsin, Virginia, and Tennessee.
                  Table 1.    Commercial Slaughter in 48 States

Beef
Hogs
Calves
Sheep & lambs
TOTAL
Live Wei
Kille
(millic
of pounc
1971
36,588
22,535
919
1,111
61,153
ght
.d
ns
is)
1972
37,126
20,249
767
1,081
59,223
Percent
of Total
in 1972
62.7
34.2
1.3
1.8
100.0
Percent
Change
Since
1971
+1.5
-10.1
-16.6
- 2.7
- 3.2
         Source:  Livestock Slaughter, Current Sunmary, 1972. *
Colorado, California, and Texas led in sheep and  lambs,  with about  1.8,
1.7,  and  1.5  million head, respectively.  New  York  led in calves with
0.6U million head, followed by New Jersey with  0.'28,   Pennsylvania  with
0.25, and Wisconsin with 0.23 million.
                                  10

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The  total  live weight of livestock slaughtered was about three percent
lower in 1972 than in 1971, with only beef  showing  a  small  increase.
Table 1 lists the 1971 and 1972 slaughter in terms of live weight killed
(LWK).   Beef,  with  nearly 63 percent, and hogs, with over 34 percent,
account for about 97 percent of the total slaughter.

Waste Waters from slaughtering of animals,  the processing of  meat  and
the  associated  facilities  and operations (stock yards, rendering, and
feed manufacturing)  contain organic matter  (including grease), suspended
solids, and inorganic materials such as  phosphates  and  salts.   These
materials  enter the waste stream as blood, meat and fat, meat extracts,
paunch contents, bedding, manure, curing  and  pickling  solutions,  and
caustic or alkaline detergents.

                          PROCESS DESCRIPTION

A  general  flowsheet of a typical full-line packing plant, or "packing-
house", is shown in Figure 1.  Such a plant is a  "packinghouse"  rather
than  a  "slaughterhouse"  by  virtue  of  the  "processing" step.  As a
packinghouse, processing  will  include  a  wide  range  and  volume  of
products.   For  example,  processed products maybe more for the animals
killed at the site.   Such a packinghouse is termed "low processing."  On
the  other hand, a packinghouse may bring in carcasses from other plants
and process much more than is killed at the site.  Such  a  packinghouse
is  termed  "high  processing".   Less  complete plants would operate on
appropriate parts of the flowsheet of Figure 1.   For  example,  primary
processes   through   cooling   of   carcasses   are   typical   of  all
slaughterhouses,  or  abattoirs.   The  secondary  processes  of   blood
processing, hide processing, and rendering may or may not be carried out
in  the  slaughterhouse.   Most  pork  plants include processing to some
extent; many beef plants, however, are only abattoirs.  A slaughterhouse
may have all of  the  operations  of  a  packinghouse,  except  for  the
processing,  cutting  and  deboning steps, as noted in Figure 1.  Such a
slaughterhouse, based on high waste load from secondary processes, would
be termed a "complex" slaughterhouse.   A  slaughterhouse  may  also  be
extremely  simple;  the  simplest kind, with no secondary processing, is
shown in Figure 2.  If the plant has relatively few secondary processes,
and those processes are of a type that give a low waste load, the  plant
is termed a "simple" slaughterhouse.

The  meat  packing operations begin at the point at which animals arrive
at the plant and carry through the shipping of the product to the whole-
sale trade  (or sometimes directly to the retailer).  In the case of very
small operations such as meat lockers, the product may  go  directly  to
the  consumer.   All processes and handling methods and their management
are considered part of the plant system.  These  include  not  only  the
processes  directed  toward  the  production  of,food products, but also
those  involved  in  recovery  of  materials  of  value  for  by-product
manufacture,  such  as  animal  feed ingredients.  The latter processes,
                                  11

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indicated as secondary processes in Figure  1,   include  those  recovery
steps  such as screening and gravity separation for proteinaceous solids
and grease, and also serve to  reduce  the  plant  waste  load.    Hence,
processes  often considered primary waste treatment are actually part of
the plant system, even though their  effectiveness  will  have  a  large
bearing  on the plant's raw waste load.  For the purposes of this study,
"primary" waste treatment refers to these in-plant control measures.

The number of processes carried out  and  the  way  in  which  they  are
carried  out  varies  from  plant  to  plant, and has an effect upon the
effluent treatment requirements.  It is convenient to  discuss  them  in
terms of the processes listed at the beginning of the next sub-section.
                                  12

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o
8.
Processes 0 . .
• Products
Primary | Secondary
I
Pr
1
Animals
Livestock
Pens
st
Killing
X
Hide Removal
Hog Dehairing
X
Eviscerating
Trimming
si
Cooling
X
Cutting
Deboning
\t ^~
Processing
Grinding
Curing
Pickling
Smoking
Cooking
Canning



-s.

n 	 — - ^



Hide Processing
Hair Recovery


^ Hides
Hog Hair

viscera nunuiiiig
' 	 ^Tripe , etc .
>.
•v


^
' J

Inedible
Nendering ^


Edible
Rendering


ocess Water

1

System

	 > By-Products
„.._.,. "^ TI it M/int
^Lard
Edible tallow

      Source:   Industrial Waste Study  of the Meat  Product Industry*


               Figure 1.   Process Flow in a Packing  Plant
                               13

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        Animals
            x
         Livestock

          Pens
          Killing
       Hide Removal

      Hog  Dehairing
        Eviscerating

         Trimming
          Cooling
        to
  -> Outside
    Processing
     Minor By-Product

       Processing
-> Carcasses
Figure 2.  Process Flow for Slaughterhouse

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                        MANUFACTURING PROCESSES

Production related activities at meat packing plants include:
         Animal stockyards or pens
         Slaughtering, which in turn, includes:
              Killing
    1.
    2-
              Killing
              Blood processing
              Viscera handling and offal washing
              Hide processing
    3,   Cutting and deboning
    4.   Meat processing
    5.   Rendering
              Edible
              Inedible
    6.   Materials recovery (primary separation)

As  indicated in a general waste flow diagram for a packinghouse, Figure
3, all of these processes contribute to the raw waste  load  except  the
materials  recovery  or  primary  separation step; this removes material
that would otherwise be discharged.


                          Stockyards and Pens


In most meat packing plants, animals are held in holding pens  for  less
than one day.  The animals are usually watered but not fed while waiting
their  turn  for  slaughter.   The pens are often covered for protection
from the elements, and sometimes are enclosed.  In  winter  in  northern
climates  they  may  be  heated  enough to minimize condensation.  Waste
water results from watering troughs, from periodic  washdown,  and  from
liquid wastes from the animals.  Runoff, if the pen is not covered, also
contributes  wasteload.   These  waste  waters are usually contained and
enter the sewer downstream of  any  materials  recovery  processes,  but
before biological treatment.
                              Slaughtering


The  slaughtering  of animals includes the killing (stunning, sticking--
cutting the jugular vein, bleeding) and hide removal for cattle,  calves
and sheep, and scalding and dehairing for hogs; eviscerating; washing of
the  carcasses, and cooling.  In the present context blood, viscera, and
hide processing are included as subprocesses.  Not all plants carry out
                                  15

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Wo
Solid
ste
Liquid
Primary
Proc
iesses
Secondary
                            Animals
                            Uvestock
                              Pens
L _
   "
          i  Manure I
!     r
     k--
  ~T
                             Killing
                                              Blood Processing
         	I
                           Hide Removal
                          Hog Oehairing
                                              Hide Processing
                                                Hair Recovery
                           Eviscerating
                            Trimming
                                              Viscera Handling
                   _i	L	Ji
                             Cooling
                             Cutting
                            Deboning
                                                  Inedible
                                                 Rendering
                          Processing
                              Grinding
                              Curing
                              Pickling
                              Smoking
                              Cooking
                              Canning
                                                  Edible
                                                 Rendering
 Solid Waste
i Composting
I  Land Fill
              Secondary
              Treatment
                  ^	i
           Final Effluent
         Figure  3.     Waste Water Flow  Diagram  for  a
                       Packinghouse.
                                                                       ~1
                               16

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all operations; for example, some only follow a narrower  definition  by
shipping out blood, hides, and viscera for processing elsewhere.

Animals  taken from the pens are immobilized upon entering the kill area
by chemical, mechanical or electrical means.  Cattle are usually stunned
by a blow to the brain.  A steel pin driven by a powder charge or by air
pressure delivers the blow.  Hogs are immobilized by an  electric  shock
from  electrodes placed on the head and back, or by running them through
a tunnel where they breath a carbon-dioxide atmosphere.  The latter is
becoming rare.  Stunned cattle are suspended  by  a  hind  leg  from  an
overhead rail for sticking and bleeding.  Immobilized hogs are hung over
a  bleeding  trough or are placed on a conveyor with their heads hanging
over the bleeding trough.  When they are stuck, the  blood  drains  into
the  trough  for collection.  During bleeding, the conveyor carrying the
animal moves slowly over the trough or gutter that catches the blood  so
it  can be collected for blood processing.  Sheep, lambs, and calves are
generally handled like cattle.  some blood spills  or  splashes  outside
the  collecting  area,  especially  as the carcasses are conveyed to the
next operation.  Also, clean-up operations wash considerable blood  into
the sewer.

Following  bleeding,  the  hides are removed from the cattle, usually by
mechanical  means.   Before  pulling,  the   hide   is   separated   (by
conventional  or  air-driven,  hand-operated  knives)  sufficiently  for
fastening to the hide puller.  Air knives are gaining  favor  because  a
skinner can be trained to use them very quickly and there is less chance
of  damaging the hide.  The most common hide puller pulls the hide "up";
i.e., from the neck to the tail, after the head  is  removed.   A  newer
puller  pulls  downward,  over  the  head.   A traveling cage places the
operator at the proper level for  skinning  and  attaching  the  puller.
Very  small  plants  skin  by  hand.  Some blood and tissue falls to the
floor from this operation, or blood even splashes  on  walls.   Much  is
collected, but some reaches the sewer, particularly during clean-up.

The hogs are usually not skinned, but are passed through a scalding tank
of  water  at  about  130°F,  then dehaired.  The dehairing machine is a
rotating drum containing rubber fins.  As the  hog  passes  through  the
drum,  the  rubber fins abrade off the hair and water constantly flowing
through the machine carries the hair  to  screens  or  other  dewatering
device  for  recovery.   In  small  plants,  dehairing  is  often a hand
operation.  The hair is sometimes baled and sold for such  uses  as  the
manufacture  of  natural  bristle  brushes,  and for furniture stuffing.
Occasionally, it is hydrolyzed and dried for use in animal feed.    Often
it  is  disposed  of as solid waste.  Following dehairing, hog carcasses
are singed for final hair removal, and sprayed with water  to  cool  and
wash.   They  are  inspected and trimmed to remove any remaining hair or
other flaws.  Scald water and dehairing and  wash  water  contain  hair,
soil, and manure.  The final carcass washwater is relatively clean.  All
are discharged to the sewer.
                                  17

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A  trend  appears  to be developing for skinning hogs,  much like cattle.
This eliminates the scalding and dehairing.

Next,  the  carcass  is  opened  by  hand  knives  and   the  animal   is
eviscerated.   The heart, liver, tongue (cattle), and kidneys are removed
from the viscera and washed; these are sold as edible meat or  are  used
in  meat  products.  Lungs may be sold for pet food.  The balance of the
viscera is channeled to the viscera handling subprocess.  The carcass is
also trimmed and inspected.  Scrap trimmings go to rendering for  edible
or  inedible  by-products.   Blood and tissue from the  evisceration find
their way directly to the sewer and are washed  into  the  sewer  during
clean-up.   The carcasses, cut in half for beef and hogs, and left whole
for sheep and calves, are hung in a cooler where they stay at  least  24
hours.   Materials recovered during clean-up, particularly by dry clean-
up procedures, go to inedible rendering, either on- or off-site.


                            Blood Processing

Handling and processing of the blood is usually a part of the slaughter-
house operation.  However, in some cases, the blood may be  shipped  out
of  a  plant  for  processing  elsewhere.   The  blood  may be heated to
coagulate the albumin; then the albumin and fibrin are  separated   (such
as  with  a screen or centrifuge) from the blood water and forwarded for
further processing into such products  as  pharmaceutical  preparations.
The  blood  water or serum remaining after coagulation may be evaporated
for animal feed, or it may be sewered.  In most cases,  the  whole  blood
is sent directly to conventional blood dryers and used for animal feed.


                            Viscera Handling

The  beef  paunches may be handled either wet or dry.  For wet handling,
the contents of the paunches, 50 to 70 pounds of partially digested feed
 ("paunch manure")  are washed out with water and passed  over  a  screen.
The  separated  solids  go  to  solid waste handling.  The liquor passing
through the screen  is  generally  sewered.   In  dry  handling,  paunch
contents  are  dumped  on  a  screen  or other  dewatering device and the
solids are sent either to a dryer or to a truck  for  removal  from  the
plant.   In  some plants, the entire paunch contents are sewered; solids
are  later removed at the  sewage  treatment plant; it is common  to   scald
and  bleach the paunches.  The  paunch is then washed thoroughly if  it is
to be used for edible products.  Hog stomach contents are  normally  wet
processed.   A  newer  practice  is  to  send   the  entire  contents  to
processing or to haul out  for disposal elsewhere.

The  intestines may be sent directly to rendering /or they may  be  hashed
and washed and then sent to rendering.  Often,  the beef paunches and hog
stomachs  and  the  intestines  are washed and saved for edible  products.
                                   18

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For example, it is common practice to bleach the paunches for  marketing
as  tripe, and to recover hog casings and chitterlings (large intestines
of hogs).  Occasionally, paunches and stomachs are given  only  a  brief
washing  and  are  sold  for food for mink or pet food.  Stomachs may be
routed, unopened, directly to inedible rendering.  Hog intestines  still
find  some  market  as  sausage  casings  and for surgical sutures.  Any
viscera washing  or  cleaning  operation  results  in  the  contents  of
stomachs,  intestines,  etc,  as well as a considerable amount of grease
being discharged to the sewer.


                            Hide Processing

Hides may be  processed  wet  or  dry.   Wet  processing  involves  hide
demanuring, washing, and defleshing, followed by a brine cure in a brine
vat  or  raceway.   The  cure  time may be as short as 12 hours.  In dry
curing, the washed, defleshed hides are packed with salt and stacked  in
the curing room.  Often hides are only salted and hauled to other plants
or to tanneries for washing, defleshing and curing.  Washing may be done
by  batches  in  a  rotating  screen  or in a tumbler similar to a large
concrete mixer.  Defleshing is usually done by passing the hide  through
rotating scraper knives.  In very small plants both may be done by hand.
Some  effort  is  being  made  toward  transferring  some of the tannery
operations to the slaughtering plant; this allows  better  recovery  and
ensuing  wastes  to  be  channeled into animal feed.  On the other hand,
some specialty plants have come into being that take the green, unwashed
hides from the slaughtering operation and deflesh, clean, and cure  them
as  an intermediate step before they go to the tannery.  Hide processing
leads to significant loads of blood, tissue,  and  dirt  being  sewered.
The  curing  operation  contributes  salt (sodium chloride) to the waste
water.


                                Cutting

Although  meat  cutting  may  be  considered  part  of  the  "processing
operation",  it is often carried out in a separate part of the building,
or may be carried out in plants that  do  no  further  processing.   The
latter  is particularly true in the case of beef plants.  In the cutting
area, the carcasses are cut for direct marketing of smaller sections  or
individual cuts, or for further processing in the processing operations.
Trimmings  from  this  operation  that  do  not  go  to products such as
sausages and canned meats go to rendering of edible  fats  and  tallows.
Inedible  materials are rendered for inedible fats and solids.  There is
always some material that reaches the floor, and a  considerable  amount
that  adheres  to  saw  blades or conveyer systems, including meat, bone
dust,  fat  tissues  and  blood  that  can  be  recovered  for  inedible
rendering.   Much of this, however, is washed to the sewer during clean-
up.
                                  19

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                            Meat Processing

The edible portion  resulting  from  slaughtering  and  cutting  may  be
processed  in  a variety of ways.   These include the manufacture of many
varieties  of  sausages,  hams,  bacon,  canned  meats,  pickled  meats,
hamburger,  portional  cuts,  etc.    Obviously, the processing of edible
products is complex and varies from plant to plant.  Some beef cuts  are
delivered to curing rooms for preparation of corned beef.  Hog carcasses
are  cut up and hams, sides, and shoulders are generally sent to curing.
Some loins may be deboned and cured for such products as Canadian bacon.
(Most loins are packaged without  curing  for  the  retail  market.)  An
average  of about 400 kg of edible "processed" products is obtained from
the processing of 1000 kg LWK in  meat  processing  operations.   It  is
recognized  that this number can vary—it may be much higher in some hog
operations, but when edible rendered products such as  lard,  and  fresh
pork  products  such  as  loins,  which  are not considered as processed
products, are excluded, the value is  not  unreasonable.   Further,  the
value  of  400  kg  processed  product  per  1000  kg LWK  (or a ratio of
processed products to  LWK  of O.U)  forms  a  natural  break  point  in
categorizing  packinghouses—products to  LWK ratio of less than O.U are
low-processing packinghouses; high-processing packinghouses have a ratio
of at least 0.4.

The curing operation involves injecting a salt and sugar   solution  into
the  meat, usually with a multineedle injection machine.   Some curing is
done by soaking in cure solution.  Smoking is  done  in  smokehouses  at
elevated  temperatures.   Smoked flavors are also obtained by soaking in
or injecting a solution containing "liquid smoke".  Spills from  cooking
equipment,  excess cure solution spilled during injection, and materials
washed into the sewer during clean-up all contribute to the waste load.

The processing operations may be carried out either in packing plants or
in separate plants that do processing only.  The "meat packing" industry
concerns only the processing associated with packing plants.


                               Rendering

Rendering separates fats and water from tissue.  Two types of rendering,
wet or dry, may be used for either edible or inedible  products.  A.  type
of  dry  rendering  process called "low temperature" rendering is coming
into common use, particularly for edible  rendering.   Edible  trimmings
from  the  cutting  operations  that  do  not  go  into  products such as
sausages and canned meats go to rendering for  preparation  of edible fats
and tallows.  The inedible processing is carried/out in  an area  in  the
packing plant separate  from the processing of  edible products.  Inedible
products find use mainly in animal feed.
                                   20

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The materials to be rendered are normally passed through a grinder.  For
inedible   rendering,   this  includes  bones,  offal   (usually  without
cleaning), condemned animals, etc.  From there it is fed to a continuous
rendering  operation,  or  to  a  blow  tank  that  can  be  pressurized
periodically  to feed batch cookers.  Economics usually dictate the type
of process used.

Wet rendering is usually carried out in pressure tanks with 40 to 60 psi
steam added directly.  The fat phase is separated from the  water  phase
after  cooking.  The solids in the water phase are screened out, leaving
what is called tankwater.  Tankwater is frequently evaporated to a thick
protein-rich material known as "stick", which is added to animal feeds.

Dry rendering is carried out either in vessels that are  open  to  atmo-
spheric  pressure  or  are  closed  and under a vacuum.  The material is
cooked until all of the free moisture in the tissue is driven off.   The
cooked  material  is  then  screened  to  remove  the fat from the solid
proteinaceous  residue.   Dry  rendering  can  be  either  a  batch   or
continuous   operation,   depending  upon  the  equipment  used.   Batch
operations are conducted in moderate-sized agitated vessels;  continuous
operations are conducted in either agitated vessels that are long enough
to  provide  sufficient  retention  time  to  evaporate the water, or in
multistage evaporators.  Dry batch rendering is  the  most  widely  used
rendering process.

Low  temperature rendering is a fairly recent development used primarily
to produce edible  products.   In  this  process,  the  material  to  be
rendered  is first finely ground.  The mass is then heated to just above
the melting point of the fat.  Centrifugation is used to remove the non-
fatty material, and the fat is further clarified in a second centrifuge.
The water phase may be further treated in other types of  equipment  for
grease and solids recovery.

Spills  from  cooking  equipment,  collection tanks, and discharges from
equipment  washdown  further  contribute  to  total  waste   discharges.
However,  rendering  operations  serve to recover a number of materials,
(e.g., grease, fats, offal tissue) which  might  otherwise  dramatically
increase  total  plant  waste  loads.   Moreover, since material such as
grease that is less  readily  biodegradable  is  reduced  in  raw  waste
discharges,  subsequent  efficiencies  in biological waste treatment are
enhanced.


                           Materials Recovery

The waste water from the plant, excluding only the waste water from  the
holding  pens and, perhaps, paunch screening, usually runs through catch
basins, grease traps, or flotation units.  The primary purpose of  these
systems  is  not  waste  treatment  per  se,  rather  the purpose is the
                                  21

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recovery of grease,  which is sent to inedible rendering and represents a
valuable  by-product.    The  very  important  function  of  removal   of
pollutants  is  also  served.   Grease  recovery most often has been the
controlling factor,  so  the  systems  may  be  considered  part  of  the
manufacturing  operation  rather  than  a  stage in pollution abatement.
However, if the catch basin or grease trap is not adequate to  meet  the
final effluent requirement, it may be necessary to further remove grease
by  an  air  flotation  unit, with or without the addition of chemicals.
This unit functions as primary treatment although its main function   is
product recovery.

The  most  widely  used method of solids recovery employs a catch basin.
Solids  (grit, residual flesh) settle  to  the  bottom  and  are  removed
continuously  or  periodically;  grease floats to the top and is scraped
off, often continuously.  For effective recovery,  these  units  usually
have  greater  than  a  30-minute  detention  time  and  are designed to
minimize turbulence.

The best grease recovery is  accomplished  by  employing  dissolved  air
flotation  in  a tank.  The tanks are usually large enough to retain the
liquid for twenty minutes to one hour.  Air is injected into  a  portion
of  the  effluent,  pressurized,  and  recycled, or is injected into the
waste water before it enters the tank.  The  liquid  is  pressurized  to
"supersaturate"  it with air.  The liquid then enters the tank where air
bubbles coming out of solution rise  to  the  surface,  carrying  grease
particles  with  them.   The  grease  is removed by skimmers.  While the
tanks are not designed for the  most  effective  removal  of  settleable
solids,  some solids settle to the bottom and are scraped into a pit and
pumped out.
In addition to recovery systems above, some plants also recover part  of
the  settleable solids before the waste streams enter the grease removal
system by employing self-cleaning screens, either static, vibrating,  or
rotating.   The  solids  that  are  recovered from these, as well as the
solids recovered from the catch basins are  sometimes  returned  to  the
plant's inedible rendering system.
                                  22

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                       PROpyCTION^CLASSIFICATION

The  U.S.  Bureau of Census, Standard Industrial Classification Manual 4
classifies  the  meat  products  industry  under   Standard   Industrial
Classification  (SIC)  group  code  number  201  (Major Group 20).  Meat
packing plants are classified as Industry No. 2011, which is defined as:

         "Establishments primarily engaged in the slaughtering,
          for their own account or on a contract basis for the
           trade of cattle, hogs, sheep, lambs, and calves for
          meat to be sold or to be used on the same premises in
          canning and curing, and in making sausage, lard, and
                            other products."

    Abattoirs on own account or for the trade; except nonfood animals
    Bacon, slab and sliced, mitsc*
    Beef, mitsc
    Blood meal
    Canned meats, except baby foods, mitsc
    Cured meats, mitsc
    Lamb, mitsc
    Lard, mitsc
    Meat extracts, mitsc
    Meat, mitsc
    Meat packing plants
    Mutton, mitsc
    Pork, mitsc
    Sausages, mitsc
    Slaughtering plants; except nonfood animals
    Variety meats  (fresh edible organs)r mitsc
    Veal, mitsc

*mitsc - made in the same establishment as the basic materials.


                      ANTICIPATED_INpySTRY_GROWTH

Shipments of meat slaughtering and meat processing plants  in  1972  was
$23.8  billion  and  is  expected  to rise by about six percent to about
$25.3 billion in 1973.  The U.S.._Industrial	Outlgok:  1973,   estimates
that  this annual growth rate of six percent per year will be substained
through  1980 for American producers. 5

Factors  that should contribute to growth can be distinguished from those
that act to restrain this growth.
                                  23

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A. growing population and rising family incomes will continue to maintain
consumer demand for meat products.   Historically, as incomes of American
families have grown, they have substituted higher priced  food  products
such  as  meats  for  the bread and potatoes in their diets.  Demand for
beef, in particular, has continued  to grow on a per capita basis as well
as in total; for example, in 1972  the  typical  American  consumed  115
pounds  of  beef,  which was two pounds more than in 1971.  In addition,
larger quantities of portion-controlled meats  are  being  processed  in
response   to   institutional  demands  by  fast-food  outlets,  hotels,
restaurants, and other institutions.

Several factors serve to restrain potential growth of the American  meat
industry,  including  higher  meat prices, removal of import quotas, and
the availability of synthetic  (soybean protein)  substitutes.    Factors
in  higher  meat prices may be sharply reduced hog and calf slaughter in
1972, for an overall decrease of more  than  three  percent  from  1971.
Supplies  must  increase  sharply  during the remainder of the decade to
achieve the projected growth rates.  Although firms in the industry have
installed new plants and equipment, the resulting  increased  efficiency
has  been  more  than  offset  by  higher  costs  for  labor, livestock,
packaging materials, and transportation—-costs that have been passed  on
to consumers in the form of higher retail prices.  On the other hand, it
is  expected  that new plants will be built to replace those that become
obsolete and are no longer economically feasible to operate.  Also,  new
plants  will  be needed to satisfy an overall growing demand for meat as
the population and  faimily incomes  increase.   The  trend  is  for  new
plants  to be larger and perhaps more specialized  (such as large beef or
pork slaughterhouses) and to be located near the  animal  supply.   This
means  that  plants  will  continue  to move away from the consumer  (the
large city) to the  more rural  areas  where  the  large  feed  lots  are
located.

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                               SECTION IV

                        INDUSTRY CATEGORIZATION


                             CATEGORIZATION

In  developing  effluent limitations guidelines and standards of perfor-
mance for the meat packing industry, a judgment was made as  to  whether
limitations  and  standards are appropriate for different segments (sub-
categories)  within the industry.  To identify  any  such  subcategories<
the following factors were considered:

    o    Waste Water characteristics and treatability
    o    Final products
    o    Primary manufacturing processes
    o    Secondary manufacturing processes
    o    Raw materials
    o    Size, age, and location of production facilities.

After  considering  all of these factors, it was concluded that the meat
packing industry consists of  two  major  groups:   slaughterhouses  and
packinghouses which are defined below.

         ^ slaughterhouse is a plant that slaughters animals and has
         as its main product fresh meat, usually carcasses broken
         down no smaller than quarters.

         A packinghouse is a plant that both slaughters and processes
         fresK meat to cured, smoked, canned, and other prepared meat
         products. *

Each  of  the  above  groups  was  further subdivided into two segments,
giving a total of four subcategories:

    I.   Simple Slaughterhouse—is defined as a slaughterhouse that
         does a very limited amount of processing of by-products
         (i.e., secondary processing).  Usually, no more than two
         secondary processes, such as rendering, paunch and viscera
         handling, blood processing, or hide or hair processing are
         carried out.

   II.   Complex Slaughterhouse—is defined as a slaughterhouse that
                                  25

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         does extensive processing of by-products (i.e.,  secondary
         processing) .   It usually carries out at least three of the
         secondary processes cited under simple slaughterhouse.

  III.    Low-Processing Packinghouse—is defined as a packinghouse
         that normally produces processed meat* less than the total
         animals killed at the site, but may process up to the
         total killed.

   IV.    High-Processing Packinghouse—is defined as a packinghouse
         that produces processed meat* both the total kill at the site
         and additional carcasses from outside sources.


*Processed meat products are limited to:  chopped beef, meat stew,
canned meats, bacon,  hams  (boneless, picnic, water added), franks,
wieners, bologna, hamburger, luncheon meat loaves, sausages.

The differences between the four  subcategories  and  the  relationships
between  them is shown schematically in Figure U.  The simplest plant is
a Simple Slaughterhouse,  and  it  does  little  secondary   (by-product)
processing.   By  adding  substantial  secondary  processing,  the plant
becomes  a  complex  Slaughterhouse.   By  adding  a   meat   processing
operation, but processing less than produced in the plant as fresh meat,
 (processing  less  than  the  plant  kills),  the  plant  becomes  a Low
Processing Packinghouse.  When the plant processes more  than  it  kills
 (e.g.,   brings  in  carcasses from outside in addition to processing its
own),  it  becomes  a  High  Processing  Packinghouse.   The  degree  of
secondary processing conducted at any packinghouse is somewhat variable,
although  a large number of by-produqt recovery operations are typically
practiced.  The basic slaughter capacity of a plant was not  an  adequate
criterion  for  categorization.   However,  there  is a tendency for the
smaller capacity slaughterhouses to  do  little  by-product  processing,
thus  to  fall  in  the  simple  slaughterhouse  subcategory.  The large
capacity slaughterhouses, on the other hand tend to do  more  by-product
processing, thereby falling in the complex subcategory.  These slaughter
capacity tendencies are reflected in the kill averages for each of these
subcategories, as indicated in Section V.

The packinghouses slaughter animals and prepare processed meat products.
Those  plants  in  the  low processing subcategory tended to have larger
slaughter  capacities  but  produce  a  smaller  quantity  of  processed
products in comparison with the high processing packinghouses.

The  normalized waste water flow  (liters per 1000 kg LWK) increases with
kill rate.  It also increases with  increased  production  of  processed
meat  products,  and  apparently  at  a  faster  ,rate than for slaughter
operations alone.  Thus, the normalized waste water flow increases  from
simple  slaughterhouses  to  complex  slaughterhouse  to  low^processing
                                  26

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packinghouses,  and  finally   to   the   maximum   in   high-processing
packinghouses.   As  indicated  in  other  sections  of this report, the
wasteload, which includes most of the pollution parameters described  in
Section   VI,   increases   with   increased  total  water  consumption.
Therefore, the larger waste load reported in Section V for subcategories
with greater water consumption is as expected.


                      RATIONALE FOR CATEGORIZATION

             Waste Water Characteristics and Treatability

Industrial practices within the meat packing industry  are  diverse  and
produce  variable  waste  loads.   It is possible to develop a rationale
division of the industry, however, on the basis of factors  which  group
plants   with  similar  raw  waste  characteristics.   The  waste  water
characteristic used in categorizing the industry is five-day biochemical
oxygen demand (BODS)  in units per 1000  units  live  weight  killed:  kg
BOD5/1000  kg LWK  (Ib BOD5/1000 LWK).  BODS provides the best measure of
planlp  operation  and  treatment  effectiveness  among  the   parameters
measured,  and  more  data  are  available than for all other parameters
except suspended solids.  Suspended solids data  serve  to  substantiate
the conclusions developed from BODS in categorizing the industry.

The  major plant waste load is organic and biodegradable: BODS, which is
a measure of biodegradability, is the best measure of the load  entering
the  waste  stream from the plant.  Furthermore, because secondary waste
treatment is a biological process, BODS also provides a  useful  measure
of  the treatability of the waste and the effectiveness of the treatment
process.  Chemical oxygen demand  (COD) measures  total  organic  content
and some inorganic content.  COD is a good indicator of change, but does
not  relate  directly  to biodegradation, and thus does not indicate the
demand on a biological treatment process or on a stream.

As developed in more detail in Section V, specific differences exist  in
the  BODS  load  for  raw  wastes  for  four  distinct groupings of meat
products operations.   As defined above, these groupings  (by plant  type)
are substantiated as sutcategories on the basis of waste load.

A  number  of  additional  parameters were also considered.  Among these
were nitrites and nitrates, Kjeldahl nitrogen, ammonia, total  dissolved
solids, and phosphorus.  In each case, data were insufficient to justify
categorizing  on  the  basis  of  the specified parameters; on the other
hand, the data on these parameters helped to verify judgments based upon
BODS.
                                  27

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                                  28

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Judging from secondary waste treatment effectiveness and final  effluent
limits;  waste  waters from all plants contain the same constituents and
are amenable to the same kinds of biological treatment concepts.  It was
anticipated that geographical location, and hence climate, might  affect
the  treatability of the waste to some degree.  Climate has occasionally
influenced the kind of secondary waste treatment used, but has  not  had
an  influence on the ultimate treatability of the waste or the treatment
effectiveness, given careful operation and maintenance.


                             Final Products

The final products of a meat packing plant provide further  support  for
the  selected  subcategorization.   Final  products  relate  directly to
processes employed, as discussed below.  A plant that processes meat  to
products  such  as  canned,  smoked,  and  cured  meats is significantly
different from a plant that does no processing.  Thus, there is a  clear
distinction  between  a  packinghouse—^a  plant that both slaughters and
processes—and a slaughterhouse.

Because of product differences, a further division of  packinghouses  is
justified;  some  plants  process  no  more  than  they kill, and others
process far more by bringing in additional carcasses and meat cuts  from
other  plants.   Therefore, packinghouses divide into*two subcategories,
depending on the amount of final product that they produce.

         Low-Processing Packinghouse—has a ratio of weight of pro-
         cessed products to live weight killed less than 0.4.  This
         numerical designation actually approximates the ratio of
         weight for beef animals, when the entire
         carcass is processed  (i.e., forty percent of the weight of
         a live animal ultimately is processed into final products) .
         For purely hog operations this ratio may reach 0.55 or higher due
         to efficiencies in carcass utilization.
         However, excluding rendered products results in an
         average situation where the ratio 0.4 appears reasonable
         It is noteworthy that in practice, these plants have
         an average ration not of 0.4, but about 0.14.  This low
         ratio indicates that, on the average, low processing
         plants process only about a third of their kill.

         High-Processing Packinghouse--has a ratio of weight of pro-
         cessing products to live weight killed greater than 0.4.  From
         the earlier definition, such a plant must bring in carcasses
         from outside sources for processing.  For these types of
         plants the average ratio is about 0.65—high processing
         plants, on the average, process about one-third more carcasses
         than animals killed at the site.
                                  29

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The inedible by-products of a meat packing plant  (i.e.,  tallow,  dried
blood,  tankage, dried solids)  also affect categorization.  However, the
methods of by-product • manufacture  vary  greatly,   and  the  effect  of
recovered  by-products  upon  categorization  is discussed in "Secondary
Manufacturing Processes".


                    Primary Manufacturing Processes

The primary manufacturing processes include the storage and slaughtering
of animals and the dressing (evisceration), cutting, and  processing  of
carcasses.   As diagrammed iri Section III, Figure 1, there is a distinct
difference between the types and amounts of primary processes in various
plants.  Together with final products, this factor enhances the logic of
the chosen subcategories.


                   Secondary Manufacturing Processes

Secondary manufacturing processes are those  by-product  operations  for
the handling, recovery, and processing of blood, trimmings, and inedible
offal.  This includes paunch and viscera handling, hide processing, hair
recovery  and  processing, and edible and inedible rendering.  Secondary
processes used interrelate  with  both  the  final  products  and  waste
characteristics;  however,  the  kind  of  manufacturing process is more
relevant than the specific by-product.   The  process  by  which  a  by-
product  is  made  determines the waste load.  Thus, it is the nature of
the secondary processes rather than by-products themselves which  define
the   categories.   Unfortunately,  there  are  a  number  of  secondary
manufacturing processes that can be used within  each  by-product  area.
Furthermore,  there   is  no  typical  or  usual combination of secondary
manufacturing processes in the industry.  Therefore, some other means of
grouping plants by secondary manufacturing processes is required.

Computer analysis, literature, and experience indicated  that  empirical
weighting  factors   (relative  'contributions to waste  loads) assigned to
each  secondary processing technique would permit a further  analysis  of
the   slaughterhouse subcategory wherein the types and  amounts of seconds
ary processes prove critical.

Therefore, waste loads in terms of kg BOD5/1000 kg LWK (Ib BOD5/1000  Ib
LWK)   were  estimated  for  each  secondary  process  that  contributes
materially to the raw waste load.  Estimates were made from  discussions
with  consultants,  data obtained in this study, and from the experience
of the investigators.  As summarized in the subcategory definitions  and
w§st£ characteristics  Sections abovet the waste load factors should be
considered relative to each gtHer rather  than  as "absolute  waste" load
values^  The factors  applied to the secondary processes were:
                                  30

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         Process                               Factor

Paunch handling:
     wet dumping                                1.0
     dry dumping                                0.1

Blood processing:
     Steam coagulated and screened or
     centrifuged, with blood water sewered      1.2
     whole blood dried                          0.3

Rendering (edible or inedible)
     wet and low temperature,
     sewering water                             2. 0
     Dry                                        0.5

Hide processing
     Defleshing, washing, curing                1.5

Hair processing
     Hydrolyzing                                1.0
     Washing                                    0.7

Viscera Handling
     Casing saving, hashing and washing,
     or stomach and chitterling washing         0.6
     Tripe processing                           0.4

The  waste load factors for the secondary processes were summed for each
slaughterhouse.   The  sum  of  the  waste  load  factors  divided   the
slaughterhouse   sample   into  two  distinct  clusters,  one  group  of
slaughterhouses with totals below 4.0 and  the  other  above  4.0.   The
plants  with totals below 4.0 were relatively simple; i.e., they had few
secondary processes and those processes tended to be the types that were
low  waste  load  contributors.   These  "simple"  slaughterhouses   had
relatively  low  total  waste loads.  The plants with waste load factors
above 4.0  were  much  more  complex;  i.e.,  they  had  many  secondary
processes.   These "complex" slaughterhouses had distinctly higher waste
loads.

The waste load factors serve an  additional  purpose.   Occasionally,  a
plant  in one of the subcategories will conduct an unusually high amount
of secondary  processing  as  an  example,  one  complex  slaughterhouse
currently processes hides from several other plants.  Its raw waste load
is  unusually  high.   However, when a waste load of 1.5 kg BOD5/1000 kg
LWK  (1.5 Ib BOD5/1000 Ib LWK, or about 1.5 Ib BODS per  hide  processed)
is  taken  into  account  for the extra hides processed, the total waste
load for the plant can be explained and  the  relation  of  other  waste
sources to those from the hide processing is established.
                                  31

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                             Raw Materials

Raw  materials  characteristics  help to substantiate the above categor-
ization.  The raw materials include live animals (cattle,  hogs,  sheep,
lambs,  and  calves),  water,  chemicals,  and fuel.   Although different
kinds of animals vary greatly in size and require  some  different  pro-
cessing techniques, these effects are best handled by incorporation into
other  factors.   For  example,  weight  variations are accounted for by
normalizing  (dividing) waste parameter values by the daily  live  weight
killed;  this gives a waste load per unit of raw material independent of
the kind of animal.  Plant process options or alternatives are dependent
on  the  kind  of  animal,  mainly  in   by-product   processing.    The
consideration of these process options in categorization is described in
the  section  above  on secondary manufacturing processes.  The industry
subcategories have the following distribution of animal type  slaughtered
which  clearly   shows   a   difference   between    slaughterhouse   and
packinghouse,  but  which  also reveals  no significant difference within
either  of   these  two   groups,   thus   further    substantiating   the
categorization.

A  definite  relationship was found between raw waste load and water use,
both  in individual plants  and  in the four subcategories.  Variations  in
water   flow   between  subcategories  are caused  by  different process
requirements.  Highly varying  water   use in  plants  within  the  same
subcategory  are  the  result of  varying  operating  practices.
Animal
Type
Beef,
only
Hogs,
only
Beef &
hogs &
Other
Total
Simple
Slaughterhouse
52., 6
26.3
21.1
100.0
Complex
Slaughterhouse
61.1
27.8
11.1
100.0
Low-Processing
Packinghouse
14.8
25.9
59.3
100.0
High-Processing
Packinghouse
9.1
40.8
50.1
100.0
Total
31.4
30.2
38.4
100.0
                                   32

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Chemicals used in packing plants (i.e., preservatives, cure, pickle, and
detergents)   do not serve as a basis for categorization.  Differences in
waste loads caused by chemicals are the result  of  different  operating
practices.

Fuels  are  usually  natural  gas  or  fuel oil.  They have no effect on
categorization.


                        Size, Age, and Location

Size, age, and location are not meaningful factors for categorization of
the industry.  Neither the information from this study,  nor  that  from
previous  studies,  reveals  any  discernible relationship between plant
size and effluent quality or other basis for  categorizing.   Both  high
and  low  quality  raw  wastes were found at both ends of the plant size
spectrum within the industry.  The very small plants may use a table  or
bed  instead of a rail to support the animal carcass in the slaughtering
operations.   This practice has no known effect on  the  raw  waste  load
from  small  plants,  relative  to  categorization,  but  it may greatly
facilitate waste disposal  for  these  plants.   Other  factors  perhaps
related  to  plant  size,  such  as  degree  of by-product recovery, are
discussed elsewhere.

Age as a factor for categorization might be  expected  to  be  at  least
amenable   to   quantitative   identification  and  interpretation,  but
unfortunately age does not even achieve that degree of usefulness.   The
meat  packing industry is a relatively old industry, and some old plants
incorporate early operating ideas and practices.  Some  plants,  on  the
other  hand, are very new and incorporate the latest operating ideas and
practices.  Nevertheless, most older plants have been updated by changes
in plant processes and plant structure.  Therefore, to say that a  plant
was  built  50  years  ago  and  is  50  years  old  is not particularly
meaningful in terms of interpreting in—plant practices.  In fact, within
the study sample the two plants with the lowest waste load  differed  in
age  by  about  50  years.   Consequently, no consistent pattern between
plant age and raw Waste characteristics was found.

Examination of the raw waste characteristics relative to plant  location
reveals  no  apparent relationship or pattern.  The effect of manure and
mud-coated animals processed in the winter by northern  plants  was  not
found to be significant.  The type of animal handled, which is sometimes
influenced  by location, does not seem to affect the waste load or other
measure of categorization.
                                  33

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                               SECTION V

                  WATER USE AND WASTE CHARACTERIZATION

                      WASTE WATER CHARACTERISTICS


Water is a raw material in the meat packing industry  that  is  used  to
cleanse  products  and  to  remove  and  convey  unwanted material.  The
principal operations and processes in meat packing  plants  where  waste
water originates are:

    o    Animal holding pens

    o    Slaughtering

    o    Cutting

    o    Meat processing

    o    Secondary manufacturing  (by-product operations)
         including both edible an4 inedible rendering

    o    Clean-up

Waste  Waters  from  slaughterhouses  and  packinghouses contain organic
matter  (including grease), suspended  solids,  and  inorganic  materials
such as phosphates, nitrates, nitrites, and salt.  These materials enter
the  waste stream as blood, meat and fatty tissue, meat extracts, paunch
contents, bedding, manure, hair, dirt, contaminated cooling water losses
from edible and  inedible  rendering,  curing  and  pickling  solutions,
preservatives, and caustic or alkaline detergents.


                       Raw Waste Characteristics

The  raw  wasteload  from  all  four  subcategories  of the meat packing
industry discussed in the following paragraphs includes the  effects  of
in-plant  materials  recovery  which incidentally serves the function of
primary waste treatment.

The parameters used to characterize the  raw  effluent  were  the  flow,
BODS, suspended solids  (SS), grease, chlorides, phosphorus, and Kjeldahl
nitrogen.   As  discussed  in  Section  VI, BOD5 is considered to be, in
general, the best available measure of the wasteload.   Parameters  used
to  characterize  the size of the operations were the kill  (live weight)
and amount of processed meat products produced.  ' All  values  of  waste
parameters are expressed as kg/1000 kg LWK, which has the same numerical
value  when  expressed  in  lb/1000  Ib  LWK.   In  some  cases, treated
                                  35

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effluents are so dilute that concentration becomes limiting.    In  these
cases,  concentration  is expressed as milligrams per liter,  mg/1.   Kill
and amount of processed meat products are expressed in thousands of kg.


Using information from the sources and methods outlined in Section  III,
the  following  Tables  2  through  5  include a summary of data showing
averages,  standard  deviations,  ranges,  and  number  of  observations
(plants)   is  presented  in  the following sections for each of the four
subcategories of the industry.


                            Slaughterhouses

A typical flow diagram illustrating the sources of waste waters in  both
simple  and  complex slaughterhouses is shown in Figure 5.  It should be
noted that a simple slaughterhouse normally conducts very few of the by-
product operations (secondary processes)  listed in Figure 5,  whereas  a
complex  slaughterhouse  conducts  most  or  all  of them.  occasionally
slaughterhouses may not have waste waters from some  of  the  operations
shown, depending upon individual plant circumstances.  For example, some
slaughterhouses  have dry animal pen clean-up with no discharge of waste
water, some have little or no cutting, and other  may  have  a  separate
sewer for sanitary waste.

The  flow  diagrams  include  both beef and hog operations.  As noted  in
Section IV, no distinction was made in subcategories  for  the  type   of
animal.  It is recognized, however, that in some small plants there will
be more significant differences in pollution wasteloads depending on the
animal  type.   These  cases,  however,  are still within the wasteloads
cited for the subcategory.
Simple^ S laughterhguse s
Table 2 summarizes the plant and raw waste characteristics for a  simple
slaughterhouse.   The table shows that 24 of the 85 plants analyzed were
simple slaughterhouses  (about one-half were beef and the others  divided
between  hogs and mixed kill) and that the BODS wasteload covers a range
from 1.5 to 14. 3  kg/1000  kg  LWK   (same  value  in  lb/1000  lb  LWK) .
Defining small plants as those with a^ LWK of less than 43,130 kg  (95,000
Ibs) ,  and  medium  plants  as  those  with  a LWK between 43,130 kg and
344,132 kg  (758,000 lb) , it can be stated that  only  small  and  medium
plants were included.   In fact, two are small and twenty- two are medium.
                                  36

-------
 Raw
Water
          Animal Pens
         Slaughtering
             Kill
         Hide Removal
         Evisceration
            Paunch
        Scalding & Hair
            Removal
                           Screening
            Cutting
v
      By-Product Operations
             Blood
             Hides
             Hair
             Tripe
           Rendering
            Casing
            S aving
                                                Materials
           Recovery
                           (except  hair  & hides)
Ancillary Operations
   Laundry
   Facilities
   Boiler
   Slowdown
                                 Sanitary Facilities
                              Raw Wastewater
                                from
                              Slaughterhouse
              Figure 5.  Operating and Wastewater Flow Chart
                          for Simple and Complex Slaughterhouses
                                 37

-------
Table  3  summarizes the plant and raw waste characteristics for complex
slaughterhouses.  Nineteen  of  the  85  plants  analyzed  were  complex
slaughterhouses (11 were beef; 6, hogs; and 2,  mixed).   Defining a large
plant  as  one wj.th a LWK of greater than 344,132 kg (758,000 Ib), and a
medium plant as in the paragraph above, the kill data of Table  3  shows
all  complex  slaughterhouses  included  are  either  medium  or  large.
Actually about one-third were large.


                             Packinghouses

A typical flow diagram illustrating the sources of waste waters in  both
low and high-processing packinghouses is shown in Figure 6,  As defined
in  Section  IV,  the main difference between a low- and high-processing
packinghouse is the amount of processed products relative to kill; i.e.,
a ratio of less than 0.4 for a low- and greater than  0,4  for  a  high-
processing   plant.   As  a  resultf  the  wasteload  contribution  from
processing is less for a low-processing packinghouse.  A  comparison  of
Figures  5  and 6 shows that a packinghouse has the same basic processes
and operations contributing to the wasteload as a  slaughterhouse,  with
the  addition  of  the  meat  processing  for the packinghouse.  Another
difference is that the degree and amount of cutting is much greater  for
a  packinghouse.  In some cases, unfinished products may be shipped from
one plant to another for processing, resulting in more products produced
at a plant than live weight killed.

Low-Processing i Packinghguses

Table 4 summarizes the plant and  raw  waste  characteristics  for  low-
processing  packinghouses.   Twenty-three of the 85 plants analyzed were
low-processing packinghouses.  The average ratio of  processed  products
to  kill  in these 23 plants is 0.14, with a standard deviation of 0.09.
The low-processing packinghouses included in the analyses have  a  ratio
of  processed  products  to  LWK  well  below  the  value of 0.4 used to
distinguish between low- and high-"processing plants.   Using  the  above
definitions   of   plant   size,  the  kill  data  shows  that   all  the
packinghouses in the sample are medium or large in size.
                                  38

-------
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         Grinding Cooking
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         Smoking  Packaging
                                                          Raw Wastewater
                                                            from
                                                          Packinghouse
Figure 6.  Operating  and Wastewater Flow  (ihart
            for Low- and High-Processing Packinghouses

-------
High-Processing Packinghouses

Table 5 summarizes the plant and  raw  waste  characteristics  of  high"
processing packinghouses.  Nineteen of the 85 plants analyzed were high-
processing  packinghouses.  The range of data for the 19 plants is large
for all wasteload parameters.  The range of 0.4 to 2.14 for the ratio of
processed products to LWK suggests that much of the wasteload variations
caused by the wide variation in processing,  relative  to  kill.   Plant
size  as  measured  by  kill ranges from small to large; two plants were
small, 11 medium, and 6 large.


                        Discussion of Raw Wastes

The data in Tables 2 through 5 cover a waste water flow range of 1334 to
20,261 1/1000 kg LWK (160 to 2427 gal/1000 Ib LWK); a wasteload range of
1.5 to 30.5 kg BOD5/1000 kg LWK (1.5 to 30.5 lb/1000 Ib LWK); and a kill
range of 18.5 to 1498 kkg LWK/day  (40  to  3300  thousand  Ib/day).   A
comparison  of  the  data  from  Tables  2  and 3 for simple and complex
slaughterhouses shows that the averages of all the waste parameters  are
higher for a complex plant.  This was expected because, by the method of
categorization  of  slaughterhouses,  complex  slaughterhouses conducted
more secondary (by-product) processes.

The data listed in Tables 4 and 5 for low- and high-processing  packing-
houses  show that high-processing plants have much higher average values
for all waste parameters on a LWK basis.

Some variations in waste water flow and strength within any one  of  the
four  subcategories  can  be attributed to differences in the amount and
types of operations beyond slaughtering, such as by-product and prepared
meat processing, and the effectiveness of material recovery  in  primary
in-plant  treatment.   However,  the  major causes of flow and wasteload
variations are variations in water use and in housekeeping practices.

Excess water use removes body  fluids  and  tissues  from  products  and
conveys  them  intcf  the waste water.  The effect of waste water flow on
wasteload is discussed in more detail later in this Section.

In all four subcategories, statistical correlation analysis of the  data
revealed that the raw BODS wasteload correlates very well with suspended
solids,  with  grease,  and with Kjeldahl nitrogen on a LWK basis.  This
means that an increase (decrease)  in one parameter will  account  for  a
certain predictable increase  (decrease) in another of the parameters.

The  effect  of  plant  size  (kill) on wasteload as measured by BOD5 for
each category was assessed by  a  regression  analysis  as  outlined  in
Section  III.   The  results  showed  that  larger  plants  tend to have
slightly higher pollutional wasteloads.  This trend  is  not  caused  by
                                  41

-------
differences  in  processing.   Rather, it results from some of the plants
operating at ever increasing  throughput, often beyond the LWK for  which
the  plant  was  designed.    Under these circumstances,  housekeeping and
water management practices tend to become careless.   As  a  result,  line
speed-up overloads fixed operations such as inedible rendering and blood
handling with consequent increases in raw waste loads.

Only  four  small  plants were included in the analysis; two were simple
slaughterhouses and two were  high-processing  packinghouses.   Three  of
the  four  were substantially below the average BODS wasteload for their
subcateogry, suggesting that  small plants can meet  effluent  limits  of
larger  plants.  The only other information available on small plants is
that of Macon and Cote. *  Accurate waste  data  were  obtained  on  ten
small packinghouses in 1961.   Because there was insufficient information
on  these  plants  to  subcategorize  them  as  low-  or high-processing
packinghouses, and the plants were not identified, the results were  not
used  in  determining  wasteloads  for the various subcategories.  Those
plants that practiced blood recovery had BOD5 wasteloads between 2.7 and
8.3  kg/1000  kg  LWK;  the  other  plants  which  sewered   blood   had
considerably  higher  waste  loads.   Although  some of the data did not
include the waste load from clean-up, Macon determined that the clean-up
could add from 0,35 to 3.0 kg BOD5/1000 kg LWK.  These results  indicate
that  the  waste  load  from  small  packinghouses not sewering blood is
slightly less  than  those  from  larger  packinghouses.   This  further
substantiates that standards set for medium and large plants can be met,
without  special  hardship,  by  a  small  plant,  if the small plant is
properly equipped for blood disposal, paunch handling, and similar  high
waste-related operations.

Data in Tables 2 through 5 show that chlorides and phosphorus values are
less frequently measured than are values for the other parameters.  From
the  data  reported,  however, chlorides and phosphorus are dependent on
in-plant operations and  housekeeping  practices.   For  example,  large
amounts  of  chlorides  contained  in pickling solutions and used in the
processing of ham, bacon, and other cured products ultimately end up  in
the  waste waters.  This explains the unusually high chloride values for
high-processing packinghouses, i.e., four to six times  the  values  for
the  other subcategories, where relatively large amounts of products are
cured.

Very little  useful  information  on  other  waste  parameters  such  as
Kjeldahl  nitrogen,  nitrites,  nitrates,  ammonia,  and total dissolved
solids were reported by the 85 plants  whose  data  were  summarized  by
subcategory  in  this  section.   However,  some  information  on  these
parameters was obtained from other sources 7 and from field verification
studies conducted

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                                             43

-------
during this program.  Typical ranges are given  below  for  these  waste
parameters.   It should be noted that the values for dissolved solids in
the waste water are also affected by the dissolved solids content of the
plant water supply.

Nitrates and Nitrites as N, mg/1              0.01 - 0.85

         Kjeldahl nitrogen, mg/1                50 - 300

         Ammonia as N, mg/1                      7 -» 50

         Total dissolved solids, mg/1          500 - 25,000

Bacteria are present in the raw waste from  meat  packing  plants.   The
usual  measure  is  in  terms  of coliforms, and for these the MPN  (most
probable number) typically is in the range of 2 to H million per 100 ml.

The process waste water normally is warm; it averages about 32°C  (90°F);
it reaches a high of about 38°C  (100°F) during the kill  period,  and   a
low of about 27°C  (80°F) during cleanup.  Biological treatment processes
operate  best  und^r  warm  conditions;  e.g., the optimum for anaerobic
lagoons is about 32°C  (90°F); hence, they are facilitated by  the  waste
water temperature.

The  pH  of  the process waste water is typically in the range of 6.5 to
8.5, although on occasion it may be outside this range.  An alkaline  pH
is  important  in the operation of anaerobic lagoons, as long as it does
not get above this range.


                         PROCESS FLpW DIAGRAMS

The most typical flow arrangement used in the meat packing  industry  is
shown schematically in Figure 7.  The system is used in about 70 percent
of  the  plants  studied.  The figure shows that most of the waste water
flows through a recovery system which consists of screening followed  by
a  catch   basin.   Frequently,  the  only  waste streams to by-pass this
system are the pen washing, sanitary wastes, hog scalding and  dehairing
wastewaters,  and  hide-processing  waste waters.  Pen washings normally
pass through a manure trap and then  are  mixed  with  the  other  waste
waters  before entering further  treatment for discharge to a watercourse
or a

-------
 Raw
Water
          Animal  Pens
                                           (may follow
                                            catch basins)
By-Product Operations

Blood



„ . I
Hair p
Tripe

Rendering
Casing
Saving

^
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(except hair & h
V
Facilities
/

ides)
Domestic Uses
Laundry
Facilities


Blc
tier
jwdown
             Cooling
             Boiler
            Blowdown
                                                                      Treatment
                                                                      (Industrial or
                                                                      Municipal)
                     Figure 7.   Typical Wastewater Treatment Systeir
                                 Without Dissolved Air Flotation

-------
municipal sewer.   Only noncontaminated water,   such  as  cooling  water,
completely  by-passes  treatment;   it  usually  discharges directly to a
stream.  In plants in which barometric condensers are  used,  the  water
can  become  contaminated.  Most of this water is sent to further treat-
ment.

The second  most  frequently  used  waste  water  arrangement  is  shown
schematically in Figure 8.  In this flow arrangement, several low
grease bearing streams by-pass the screen and  catch basin.  This permits
an  increase  in  the  detention  time of the  grease-bearing stream in a
grease recovery system because the system can  now handle a  lower  waste
water flow.  Low-grease-bearing waste waters normally originate from the
pens, some secondary  (by-product)  processing,  and sanitary wastes.  This
arrangement is commonly used when dissolved air flotation is included in
primary treatment.  A portion of the effluent  from the flotation unit is
recycled to a pressurization tank where air is added for flotation.

Several modifications of the flow arrangement  shown in Figure 8 are used
by  the  industry.    Some plants add chemicals to the waste stream via a
mixing tank just prior to the flotation unit.    This  usually  increases
grease  and solid recovery but it also may increase the moisture content
of the skimmings to 85 to 95 percent, making the handling  of  skimmings
more difficult.  Other plants may have twp dissolved air flotation units
in series.  Chemicals are usually added to the waste stream entering the
second  unit.   Skimmings from the first unit are almost always rendered
while those from the  second  unit,  which  contain  chemicals,  may  be
landfilled.   A few plants add chemicals to both units to achieve a high
wasteload reduction.  Chemicals may reduce the rendering  efficiency  or
produce a finished grease that is unacceptable on the market.

A  third  flow  arrangement,  which has been installed in a few recently
built plants, is shown in Figure 9.  The purpose of this arrangement  is
to   segregate  waste  streams  according  to the type of treatment to be
applied.  In the scheme shown, the streams are divided into low and high
grease-bearing streams, and manure-bearing streams.  For example,  floor
drains  located  on   the  kill  floor  after  the carcass is opened, are
connected to the high  grease-bearing  streams;  hide  processing  waste
water  is  directed to the manure-bearing streams.  Segregation into the
three major waste streams permits optimum design of each catch basin and
flotation unit for recovery  and  waste  load  reduction,  with  minimum
investment  in equipment.  A more detailed list of the segregated  stream
contents is given by  Johnson* 8

Although there are a  number of operations where  waste  water  could  be
reused  or recycled,  the  industry is generally recycling  or reusing only
non-contaminated cooling  water, as illustrated in Figures 7, 8,  and  9.
One  minor exception is reuse of lagoon water as cooling water.

-------
 Slaughtering
 Hide Removal
 Evisceration
                         (may follow
                          ratch basins)
                               Dissolved
                               Air
                               Flotation
Scalding & Hair
    Removal
Wet  Well
& Pumps
 By-Product  Operations
                                                   Receiving
                                                   Body of
                                                   Water
Figure 8.   Typical Wastewater Treatment  System
             Including  Dissolved Air  Flotation

-------
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-------
                  WATER USE _-r WASTELOADRELATIONSHIPS

Increased  water  use causes increased pollutional wasteload in the meat
packing industry.  This  was  verified  by  regression  and  correlation
analyses  of  individual plant data over long periods (up to two years) ,
and also on the data for each of the four subcategories.   For  example,
multiple regression analysis of the data relating BOD5 wasteload to kill
and  flow  revealed  that  a  variation  of one standard deviation would
change the predicted EOC5 for a simple slaughterhouse by 1.0 kg/1000  kg
LWK  (1.0  lb/1000  Ib  LWK);  it  would change the predicted load for a
complex slaughterhouse fcy 2.8 kg/1000  kg  LWK  (2.8  lb/1000  Ib  LWK).
Another  regression analysis between BODS and flow on a LWK basis showed
that one standard deviation in flow changed the predicted  BOD5  by  5.6
and  5.3  kg/1000 kg LWK (5.6 and 5.3 lb/1000 Ib LWK) for low- and high-
processing packinghouses, respectively.

Figure 10 shows the  average  and  range  of  the  results  of  separate
regression  analysis  on  the  flow-wasteload  data  from each of eleven
plants.  This figure clearly illustrates that water use strongly affects
the pollutional wasteload.  For example, the  figures  show  that  a  20
percent  reduction  in water use would, on the average, result in a BODS
reduction of 3.5 kg/1000 kg LWK  (3.5 lb/1000 Ib LWK).

Further evidence for the dependence of pollutional  wasteload  on  water
flow  is  that,  in  three of the four subcategories, the plant with the
lowest wasteload also had the lowest water  use.   In  the  fourth  sub-
category,  the  plant  with  the  lowest wasteload had the second lowest
water use.

Low  water  use,  and  consequently  low  absolute  wasteload,  requires
efficient  water  management  practices.   For  example,  available data
showed that two simple slaughter houses practice  very  good  water  use
practices.   The plants both had wasteloads of about 2 kg/1000 kg LWK  (2
lb/1000 Ib LWK); their wastewater flows ranged from 1333 to 2415  1/1000
kg  LWK   (166  to  290  gal/1000  Ib  LWK) .   One  plant was an old beef
slaughterhouse; the other,  a new hog slaughterhouse.   This  outstanding
performance  was achieved in a sugcategory for which the flows ranged to
21,000 1/1000 kg LWK  (1750  gal/1000 Ib LWK),  and  for  which  the  BOD5
loading ganged to over 14 kg/1000 kg LWK  (14 lb/1000 Ib LWK).
                                   48

-------
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               l
  4000     6000

Liters/IOOO kg U/VK
  r
8000    10,000
        Figure 10.  Effect of Water Use on Wasteload

                  for Individual Plants

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                         SOURCES OF WASTEWATER

                              Animal Pens

Although  pen  wastes  only contain an estimated 0.25 kg of BOD5/1000 kg
LWK, 9 the wastes are high  in  nutrients.   10   Frequently,  the  solid
wastes  are  removed by dry cleaning, followed by little or no washdown.
If the pens are washed down, a manure trap is frequently used to recover
solids rather than letting them enter a treatment system.  Any  rainfall
or  snowmelt  runoff is normally contained and routed for treatment with
other raw waste flows.

Another waste water source in the pens is the  watering  troughs.   Each
trough  may discharge 8 1/min (2.1 gal/min) or more.  With perhaps 50 or
more pens in a large plant, the1 water source becomes  significant.   The
total  waste from the pens, however, is a minor contributor to the waste
load.


                              Slaughtering

The slaughtering operation is the largest single source of wasteload  in
a meat packing plant, and blood is the major contributor.  Blood is rich
in  BOD5,  chlorides,  and  nitrogen.  It has an ultimate BOD of 405,000
mg/1 and a BODS between 150,00 and 200,000 mg/1. i» Cattle contain up to
50 pounds of blood per animal, and typically only 35 pounds of the blood
are recovered in the sticking  and  bleeding  area.   The  remaining  15
pounds  of blood are lost as wastes which represents a wasteload of 2.25
to 3.0 kg BOD5/1000 kg LWK  (2.25 to 3.0 lb/1000 Ib LWK).  Total  loss  of
the  blood represents a potential BOD5 wasteload of 7.4 to 15 kg/1000 kg
LWK  (7.5 to 15 lb/1000 Ib LWK).  Because very few meat  plants   practice
blood  control  outside of the bleeding area, the typical BOD5 load from
blood losses in the slaughtering operation is estimated to be 3  kg/1000
kg LWK.  In beef plants, much of this loss occurs during hide removal.

Beef  paunch  or  rumen  contents is another major source of waste load.
Paunch manure, which contains partially digested feed  material,  has   a
BOD5  of  50,000  mg/1. 12  At an average paunch weight of  50 pounds per
head, dumping of the entire contents can contribute 2.5 kg/1000  kg  LWK.
However,  the common practices are to either screen the paunch contents,
washing the solids on the screen  (wet dumping), or to dump on  a screen
to  recover  the  solids,  allowing only the "juice" to run to the sewer
 (dry dumping).  Because 60 to 80 percent of the BOD5 in  the  paunch  is
water soluble, wet dumping of the paunch represents a BOD5  loss  of about
1.5 kg/1000 kg LWK.  If dry dumping is practiced, the pollutional waste-
load  is much less than this.  When none of the paunch is sewered but is
processed or hauled out of the plant  for land disposal,  paunch   handling
does not contribute to the wasteload.  Cooking of the rumen or paunch in
a  hot  alkaline solution  (tripe processing) will also add  to the waste-
                                   50

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load, particularly to the grease load.  The strong alkalinity  of  these
waste waters may also make grease recovery more difficult.

The hog scald tank and dehairing machine are other sources of pollution.
The overflow from a hog scald tank is usually about 8U 1/1000 kg LWK  (10
gal/1000  Ib  LWK)  at  a  BODS  loss  of  about  3000 mg/1.  This could
represent a BOD5 loss of about 0.25 kg/1000 kg LWK.  Continuous overflow
of water from the dehairing machine is estimated to contribute a maximum
BODS load of O.U kg/1000 kg LWK.

Other sources of waste from the slaughtering of animals and dressing  of
carcasses  is  from  carcass  washing, viscera and offal processing,  and
from stomach and peck flushing.

The offal operations such as chitterling washing  and  cleaning  casinqs
intestinal  can  contribute  to  the  pollution load of a plant.  T1  tne
slime waste from the casings is not sewered, the  wasteload  from  thfse
operations would be greatly reduced.

The  highest  source of water use in slaughtering is from the washing of
carcasses; an extreme example for which data are available  shows  rates
of  2915  1/min (350 gal/min).  Flushing the manure from chitterling  an 1
viscera, or conveyer sterilizing, and the tripe  "umbrella"  washer   are
other high water use operations.


                            Meat_Processing

The  major  pollutants  from meat processing are meat extracts, meat  and
fatty  tissue,  and  curing  and  pickling  solutions.   Loss  of  these
solutions   can  be  the  major  contributor  to  the  waste  load  from
processing.  The results of a recent study showed that only  25  percent
of  the  curing brine remained in the product. 11  The rest of the hrine
is lost to the sewer.  This source of chlorides,  plus  others  such  as
from  hide  curing  and  the  use  of  salt  on  the  floors  to  reduce
slipperiness, explains why some packinghouse wastes have high chlorides.
A content of 1000 nig/1 of chlorides is not uncommon in the effluent from
a packinghouse.  Another constituuent of the cure is dextrose; it has   a
BOD5  eguivalent of 2/3 kg/kg  (Ib/lb).  Conseguently, packinghouses with
a sizeable curing facility will have high BOD5 waste unless  the  wastes
from  curing  are segregated or recycled.  In one plant over 2000 pounds
of dextrose was lost daily.  13  The pollution load  from meat and  fatty
tissue  can  be substantially reduced by dry clean-up prior to washdown.
The water use in meat processing should be primarily limited to  cleanup
operations and to product washing, cooling, and cooking.
                                  51

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                   Secondary Manufacturing Processes

Secondary manufacturing processes,  as described in Section IV,  are those
by-product  operations  within  the industry for the handling,  recovery,
and processing of blood, trimmings, and inedible offal.    This   includes
paunch   and  viscera  handling,  hide  processing,   hair  recovery  and
processing,  and edible and inedible rendering.   Those viscera and  offal
operations that occur on the slaughtering floor, such as paunch handling
and tripe processing, were considered under slaughtering.

The  hashing and washing of viscera, often performed prior to rendering,
produces a strong waste load with a BOD5 value  of about 70,000  mg/1.  11
The  waste  conservation trend in the past few  years has been toward not
hashing and washing prior to rendering, but sending the  uncleaned  vis-
cera  directly  to  rendering.   In one plant,  removal of the hasher and
washer reduced the BOC5 to the waste treatment  plant  by  910  kg   (2000
pounds)  per day, with an attendant increase in the rendered animal feed
production.

Efficient recovery of hog  hair  is  now  practiced  widely  within  the
industry,  although  the  market for this by-product has been reduced in
recent years.  Very few plants hydrolyze hog hair, but rather  wash  and
bale  for  sale  or dispose of it directly to land fill.  The waste load
from the recovery and washing of the hair  is  estimated  to  contribute
less than 0.7 kg/1000 kg LWK.

Hide  curing  operations  are  becoming  increasingly  involved  at meat
packing plants.  Just a few years ago many plants  were  shipping   hides
green  or  in salt pack.  Today, however, many beef slaughter operations
include hide curing in tanks, vats, or raceways.  The  hides,  prior  to
being  soaked in brine, are washed and defleshed.  These washings,  which
are sewered, contain blood, dirt, manure, and flesh.  In most defleshing
operations the bulk of the tissue is recovered.  In  addition  to   these
wastes,  soaking  the  hide  in  the  brine results in a net overflow of
approximately 7.7 liters  (2 gallons) of brine solution per hide.    In   a
few  plants the brine in the raceway is dumped weekly, whereas in others
it is dumped yearly or whenever the solids build up  to  a  point   where
they  interfere  with  the hide curing operation.  The life of the  brine
can be extended by pumping the recycled brine over a vibrating or static
screen.  The waste load from the overflow and washings in a typical hide
curing operation, where  the  hide  curing  wastes  are  not  frequently
dumped,  is about 1.5 kg/1000 kg LWK for BODS and about  U kg/1000 kg LWK
for salt.

Blood processing may be either wet or dry.  Continuous dryers, which are
quite common, use a  jacketed vessel  with  rotating  blades  to  prevent
burn-on;  this  process results in low losses to the sewer  (estimated to
contribute about 0.3 kg BOD5/1000 kg LWK).  Continuous ring  dryers  are
sometimes  used:  they  produce a relatively small amount of blood  water
                                  52

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that, in some small  plants,  is  discharged  to  the  sewer.   The  old
technique  of  steam  sparging  the  blood  to  coagulate  it  is  still
frequently used.  The coagulated blood is separated from the blood water
by screening.  The blood water has a BODS of about 30,000 mg/1.   It  is
often  sewered,  contributing  a waste load of about 1.3 kg/1000 kg LWK.
This loss can be eliminated by evaporating the blood  water,  either  by
itself  or by combining it with other materials in conventional inedible
dry rendering operations.

Wet rendering  and  low  temperature  rendering  are  potentially  large
sources  of  pollution.   Tank  water from wet rendering can have a BODS
value of 25,000 to 45,000 mg/1,  and  the  water  centrifuged  from  low
temperature  rendering  can have a BODS of 30,000 to 40,000 mg/1.  It is
estimated that sewering of either of the waste streams produces a  waste
load  of  2 kg BODS/1000 kg LWK.  These waste loads can be eliminated by
evaporation or combining with  other  materials  used  in  dry  inedible
rendering.   Triple-effect  vacuum evaporators are often used to concen-
trate the "tankwater" from the wet rendering operation.   The  wasteload
from  wet  rendering is primarily caused by overflow or foaming into the
barometric leg of these evaporators  and  discharge  to  the  sewer  or,
sometimes  directly tc a stream.  From dry rendering the pollution comes
from the condensing vapors, from spillage, and from clean-up operations.
A recent study revealed that a typical dryer used 454 to 492 1/min   (120
to  130  gal/min)  of water for condensing vapors, and that the^ effluent
contained 11Q mg/1 of BODS and 27 mg/1 grease.  The estimated  wasteload
from dry rendering is 0.5 kg/1000 kg LWK.


                                Cutting

The main pollutants from cutting operations are meat and fat scraps from
trimming,   and  bone  dust  from  sawing  operations.   Most  of  these
pollutants enter the wastje stream  during  clean-up  operations.   These
wastes  can  be reduced by removing the majority of them by dry clean-up
prior to washdown, and also by some form of grease trap in  the  cutting
area.   The  collected material can be used directly in rendering.  Pone
dust is a large source of phosphorus and, when mixed  with  water,  does
not  settle  out readily; thus it is difficult to recover, and should be
captured in a box under the saw.


                                Clean-UjD

Macon6 found that clean-up contributes between 0.3 and 3 kg BODS/1000 kg
LWK in small packinghouses.  Data collected by the  Iowa  Department  of
Environmental  Quality showed that anywhere from 27 to 56 percent of the
total BODS waste load is contained in the clean-up  waste  waters.   The
clean-up  operation  thus  is a major contributor to the waste load.  it
also leads to a significant loss of recoverable by-products.  Detergents
                                  53

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used in clean-up can adversely affect the efficiency of grease  recovery
in the plant catch basin.

The techniques and procedures used during clean-up can greatly influence
the  water  use  in  a  plant and the total pollutional waste load.  For
example, dry cleaning of floors prior to wash down to remove scraps  and
dry  scraping  of the blood from the bleed area into the blood sewer are
first steps.  A light wash down, again  draining  to  the  blood  sewer,
before  the normal washdown definitely decreases the pollution load from
clean-up.

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                               SECTION VI

                   SELECTION OF POLLUTANT PARAMETERS


                          SELECTED PARAMETERS

Based on a review of the Corps of Engineers Permit Applications from the
meat packing plants, previous studies on waste waters from meat  packing
plants,  3,is  industry  data, questionnaire data, published reports, 1*
and data obtained from sampling plant waste waters  during  this  study,
the following chemical* physical, and biological constituents constitute
pollutants or measures of pollution as defined in the Act.

         BODS (5 day, 20°C biochemical oxygen demand)
         COD (Chemical cxygen demand)
         Suspended solids
         Dissolved solids
         Grease
         Ammonia nitrogen
         Kjeldahl nitrogen
         Nitrates and nitrites
         Phosphorus
         Chloride
         Temperature
         Bacteria
         PH

On  the  basis  of  all evidence reviewed, there do not exist any purely
hazardous types of pollutants (such as heavy metals  or  pesticides)  in
the waste discharged from the meat processing plants.


            RATIONALE FOR SELECTION OF IDENTIFIED PARAMETERS

                 5- Day Biochemical f Oxygen^ De
This  parameter is an important measure of the oxygen consumed by micro'
organisms in the aerobic decomposition of the  wastes  at  20°C  over  a
five-day  period.   More  simply,  it is an indirect measure of the bio-
degradability of the organic pollutants  in  the  waste.   BOD5  can  be
related  to  the  depletion  of  oxygen  in a receiving stream or to the
requirements for waste treatment.  Values of BOD5 range from 300 to 3800
mg/1 in the raw waste, although typical values range from  900  to  1500
mg/1.

If  the  BODS level of the final effluent of a meat packing plant into a
receiving body is too high, it will reduce the dissolved oxygen level in
that stream to below a level that will sustain  most  fish  life;  i.e.,
                                  55

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below  about  U  mg/1.   Many  states  currently  restrict  the  BOD5 of
effluents to below 20 mg/1 if the stream is small in comparison with the
flow of the effluent.  A limitation of 200 to 300 mg/1 of BODS is  often
applied  for  discharge  to  municipal  sewer, and surcharge rates often
apply if the BOD5 is above the designated limit.

A 20-day biochemical oxygen demand (BOD20) , sometimes called  "ultimate"
BOD,  is usually a better measure of the waste load than BOD5.  However,
the test for BOD20 requires 20 days to run,  so  it  is  an  impractical
measure for most purposes.
COD  is yet another measure of oxygen demand.  It measures the amount of
organic and some  inorganic  pollutants  under  a  carefully  controlled
direct chemical oxidation by a dichromate-sulfuric acid reagent.  COD is
a much more rapid measure of oxygen demand than BODS, and is potentially
very  useful.   However,  it does not have the same significance, and at
the present time cannot be substituted for BODS because COD: BODS  ratios
vary with the types of wastes.

COD  provides a rapid determination of the waste strength.  Its measure-
ment will indicate a serious plant or treatment malfunction long  before
the  BODS  can  be run.  A given plant or waste treatment system usually
has  a  relatively  narrow  range  of  COD: BODS  ratios,  if  the  waste
characteristics are fairly constant, so experience permits a judgment to
be  made  concerning  plant operation from COD values.  In the industry,
COD ranges from about 1.5 to 5 times the BODS; the ratio may be  to  the
low  end  of  the  range for raw wastes, and near the high end following
secondary treatment when the readily degraded material has been  reduced
to very low levels.


                            Suspended^§oj.ids

This  parameter measures the suspended material that can be removed from
the waste waters by laboratory filtration, but does not  include  coarse
or  floating  matter  that can be screened or settled out readily.  Sus-
pended solids are a visual and easily determined  measure  of  pollution
and  also a measure of the material that may settle in tranquil or slow-
moving streams.  Suspended solids in the waste from meat packing  plants
correlate  quite well with BODS.  A high level of suspended solids is an
indication of high BOC5.  Generally, suspended solids  range  from  one-
third  to  three-fourths of the BODS values in the raw waste.  Suspended
solids are also a measure of the effectiveness of solid removal  systems
such as clarifiers and fine screens.
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                            Dissolved Solids
                            •» -^ —• •« ^ T* • ' •«. " • •" - '•

The  dissolved solids in the raw waste water are mainly inorganic salts,
and the salt present in the largest amount is sodium chloride  (described
below).  Loadings of dissolved solids thus vary to a large  extent  with
the  amount  of  sodium  chloride  entering  the waste stream.  However,
values of 1500 mg/1 or more may be encountered.   The  dissolved  solids
are  particularly  important  in  that they are relatively unaffected by
biological  treatment  processes.   Unless  removed,   the   salts   may
accumulate  in recycle or reuse systems within a plant.  The presence of
sulfates is a further hindrance to treatment systems since sulfates  are
reduced  to sulfides (causing odors) in anaerobic system.  The dissolved
solids at discharge concentrations may  be  harmful  to  vegetation  and
preclude  various  irrigation  practices.    Specific  data for dissolved
solids in treated effluents is limited; the technical sophistication and
cost of salt removal systems is high and beyond the scope  of  even  the
best  current treatment systems addressed in this study.  Limitations on
dissolved solids are therefore not being specified at this  time.   This
same  circumstance  applies  to  chlorides  (a dissolved salt) which are
described below in more detail.
                                 Grease

Grease, also called oil and grease,  or  hexane  solubles,  is  a  major
pollutant in the raw waste stream of meat packing plants.  The source of
grease  is  primarily  from carcass dressing, washing, trimming, viscera
handling, rendering and clean-up  operations.   Grease  forms  unsightly
films on the water, interferes with aquatic life, clogs sewers, disturbs
biological  processes  in sewage treatment plants, and can also become a
fire hazard.  The loading of grease in the raw waste load varies widely,
from 0.25 to 27 kg/1000 kg LWK (0.25 to 27 lb/1000 Ib LWK).  This  would
correspond to an average concentration of about 650 mg/1.  Grease may be
harmful  to  municipal  treatment  facilities  particularly to trickling
filters.


                            Amjnon i a ^ Ni t r ocjen

Ammonia nitrogen in raw waste is just one of many forms of nitrogen in a
waste  stream.   Anaerobic  decomposition  of  protein,  which  contains
organic  nitrogen,  leads  to the formation of ammonia.  Thus, anaerobic
lagoons or digesters produce  high  levels  of  ammonia.   Also,  septic
(anaerobic)  conditions within the plant in traps, basins, etc., may lead
to ammonia in the waste water.  Another source of ammonia can be leakage
to  ammonia  refrigeration systems; such systems are still fairly common
in meat packing plants.
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Ammonia is oxidized by bacteria in a process called  "nitrification"  to
nitrites  and  nitrates.  This may occur in an aerobic treatment process
and in a stream.  Thus, ammonia will deplete  the  oxygen  supply  in  a
stream;  its  oxidation  products  are  recognized nutrients for aquatic
growth and for some toxic qualities (see below).   Also, free ammonia  in
a stream is known to be harmful to fish.

A typical concentration in the raw waste load is about 7.0 to 50.0 mg/1;
however,  after  treatment  in  an  anaerobic secondary system, the con-
centrations of ammonia can reach as high as 100 to 200 mg/1.  Ammonia is
limited in drinking water to 0.05 to 0.1 mg/1. **


                           K-jeldahl,. Nitrogen

This parameter measures the amount of ammonia and organic nitrogen; when
used in conjunction with the ammonia nitrogen, the organic nitrogen  can
be  determined  by  the  difference.   Under  septic conditions, organic
nitrogen decomposes to  form  ammonia.   Kjeldahl  nitrogen  is  a  good
indicator  of the crude protein in the effluent and, hence, of the value
of material being lost in the  waste  water.   The  protein  content  is
usually  taken  as  6.25  times  the  organic  nitrogen.  The sources of
Kjeldahl nitrogen are basically the same as for ammonia nitrogen, above,
except for the refrigeration system.  The raw waste loading of  Kjeldahl
nitrogen  is  extremely  variable  and  highly affected by blood losses.
Typical loadings range from O.OU to 6.76 kg/1000 kg LWK   (0.04  to  6.76
lb/1000  Ib  LWK),  and  concentrations  range from about U to 750 mg/1.
Typical raw waste concentrations of Kjeldahl nitrogen are between 50 and
300 mg/1.


                         Nitrates^and Nitrites

Nitrates and nitrites, normally reported as N, are the result of  oxida-
tion  of ammonia and of organic nitrogen.  They may also enter the waste
stream from use in the plant as preservatives-  Nitrates  are  important
in  the  water  supply  used for human or livestock consumption, because
high nitrate  concentrations  can  be  toxic.   Nitrates  are  essential
nutrients  for  algae  and  other  aquatic  plant  life  and   should  be
minimmized to preclude eutrophication in watercourses.
                                  58

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                               Phosphorus

Phosphorus,  commonly reported as P,  is  another  primary  nutrient  for
aquatic  plant  life  and  can  therefore  cause eutrophication in water
courses.  The threshold concentration of phosphorus in receiving  bodies
that  can lead to eutrophication is about 0.01 mg/1.  The primary source
of phosphorus in raw  waste  from  meat  packing  plants  is  bones  and
detergents.    The total phosphorus in the raw effluent ranges from about
0.01 to 0.63 kg/1000 kg  LWK  (0.01  to  0.63  lb/1000  Ib  LWK),  or  a
concentration range of 15 to 50 mg/1.


                               Chlorides

Chlorides  in  concentrations  greater  than 5000 mg/1 can be harmful to
people and other animal life.  High chloride  concentrations  in  waters
can  be  troublesome  for  certain  industrial  uses  and  for  reuse or
recycling of water.  The major sources pf chlorides  from  meat  packing
plants  are  the  salt  from  animal  tissues,  hide  curing operations,
pickling and curing solutions, cleaning chemicals, blowdown  water,  and
that  used  to  prevent  slipping  on floors.  The concentrations in raw
waste are extremely variable from  plant  to  plant,  and  are  normally
higher  for  plants  killing cattle and treating hides than they are for
other plants.  The amount in the waste is an indicator  of  the  way  in
which  certain  processes  are  being  operated.   The range of chloride
loadings in raw waste effluents is from less than one to greater than 20
kg/1000 kg LWK  (20 lb/1000 Ib LWK).  Chloride loadings are unaffected by
biological treatment systems used by the industry today, and once in the
waste waters they are very costly to remove.  As a  result,  limitations
are not being established at this time.
                              Temperature

Because  of  the  long detention time at ambient temperatures associated
with typically large biological treatment systems used for treating meat
packing waste water, the temperature of the  final  effluent  from  most
packing  plants  will  be  virtually  the same as the temperature of the
receiving body  of  water.   Noncontaminated  cooling  waters  that  are
discharged  directly  will tend to have a maximum of 40-U3°C  (105-110°F)
during the summer months, and will be cooler at other times of the year.
The quantity of this cooling water is small compared  with  the  process
waste  water  flow.  The temperature of the raw waste typically averages
about 32°C (90°F), with a high of about 38°F   (100°F)  during  the  kill
                                  59

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period and a low of about 27°C (80°F)  during the clean-up period.   These
temperatures  are  an  asset  for  biological  treatment  of  the waste,
maintaining high rates cf growth of the microorganisms  upon  which  the
treatment depends.


                               Colif orm Bacteria

The  coliform  bacteria  contamination  of  raw  waste  is substantially
reduced in the waste treatment systems typically used  in  the  industry
such as anaerobic lagoons followed by large aerobic lagoons.  Colif orms,
measured  as  "total"  or  "fecal",  serve  as  indicators  of potential
pathogenic organisms.  Data indicate that the MPN of the total  coliform
of  the raw waste from meat packing plants is in the 2- to 4-million per
100 ml range.  In the final  effluent  of  a  typical  anaerobic-aerobic
system,  the  MPN  per  100  ml is usually several thousand.  Typically,
states require that the fecal coliform count not exceed  50-200  MPN/100
ml for waste waters discharged into receiving waters.  Hence, most final
effluents  require  chlorination  to  meet state standards as well as to
assure effective waste treatment.
The usual pH for raw waste falls between 6.5 and 8.5; unusual  processes
such  as hog hair hydrolyzing may raise this slightly, but not enough to
significantly  offset  treatment  effectiveness  or  effluent   quality.
However,  some adjustment may be required, particularly if pH adjustment
has been used to lower the pH for protein precipitation, or  if  the  pH
has  been  raised for ammonia stripping.  The pH of the waste water then
should be returned to its normal range before discharge.  The effect  of
chemical additions for pH adjustment should be taken into consideration,
as new pollutants could result.

                                 Others

Some  other  pollution  parameters are of lesser significance.  Color is
related to a number of factors such as  color  of  raw  wastes   (blood) ,
treated  waste   (lagoon  effluent) , raw waste strength, and is a visible
indicator; it is useful only for qualitative purposes.  Odor is  only   a
problem  in  the  waste  water  in  anaerobic  treatment systems., or if
aerobic systems become anaerobic.  A build-up of grease on  the  surface
of  the  anaerobic  lagoon  is sometimes utilized to functionally reduce
odor.   However,  high  sulfate  water  supply  sources  may   aggravate
malordorous conditions,
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                              SECTION VII

                    CONTROL AND TREATMENT TECHNOLOGY

                                SUMMARY

The  wasteload  discharged  from  the meat packing industry to receiving
streams can be reduced to desired  levels,  including  no  discharge  of
pollutants,  by  cpnscientious  waste  water  management, in-plant waste
controls, process revisions, and by the use of primary,  secondary,  and
tertiary waste water treatment.  Figure 11 is a schematic of a suggested
waste  reduction  program  for the meat packing industry to achieve high
removal of pollutants in subsequent treatment.

This section describes many of the techniques and technologies that  are
available  or  that are being developed to achieve the various levels of
waste reduction.  In-plant control techniques and waste water management
suggestions are described first.  Waste  treatment  technology  normally
employed  as  a primary treatment is then described.  In the case of the
meat packing industry this "primary" treatment is a  materials  recovery
process, and is considered as part of the in-plant system, although many
of  these  systems  have  been improved for reducing pollutional levels.
The effluent  from  these  processes  is  considered  the  "raw  waste".
Secondary  treatment systems, which are employed in the treatment of the
raw waste, are presented with a description of the process, the specific
advantages and disadvantages of each system, and  the  effectiveness  on
specific  waste  water  contaminants  found in packing plant waste.  The
tertiary and advanced treatment systems that are applicable to the waste
from typical packing plants are described  in  the  last  part  of  this
section.  Some of these advanced treatment systems have not been used in
full  scale  on  meat  packing  plant  waste; therefore, the development-
status, reliability, and potential problems  are  discussed  in  greater
detail than for the primary ,and secondary treatment systems which are in
widespread use.
The  wasteload  from  a  meat packing plant is composed of a waste water
stream containing the various pollutants described in Section  VI.   The
cost  and  effectiveness of treatment of the waste stream will vary with
the quantity of water and the  wasteload.   In  fact,  as  indicated  in
Section  V,  the pollutional wasteload increases as water use increases.
In-plant control techniques will reduce both water use  and  pollutional
wasteload.   The latter will be reduced directly by minimizing the entry
                                  61

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of  solids into the  waste water stream and indirectly by   reducing  water
use.

The  in-plant  control  techniques   described  below  have  been used  in
packing plants or have been demonstrated  as technically  feasible.
  Waste Reduction
    Techniques
   Waste Reduction
     Effect
     Point of
    Application
Waste
Water
Mgmt . &
In-Plant
Controls
^

Water-
Flow 6,
Waste
Load
Reduction
^




Plant
Operations

Screening,
Skimming,
Settling -
Primary
Treat.


By-Product
Recovery,
Grease,
& Coarse
Solids
Removal
i
f
In-Plant
                     Figure 11.  Suggested Meat Packing Industry Waste Reduction Program
                                       62

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                               Pen Wastes

The best livestock hglding pens are covered and dry  cleaned  with  only
periodic  washdown as required by Department of Agriculture regulations.
Bedding material and manure are readily disposed  of  on  farm  land  as
fertilizer.   A  separate  sewer  and manure pit are provided for liquid
wastes from the pens; disposal is on land or to the secondary  treatment
system.   Drinking  water  in  the  pens is minimized and based on need.
Watering troughs should have automatic level controls.


                             Blood Handling

In good practice,  blood  is  not  sewered.   Blood  is  almost  totally
contained  and  collected  in a blood collection system.  Water or steam
are not necessary to operate such a system, and both should be  avoided.
After  dry  cleaning  the  floors  and  walls exposed to blood flows and
splashing, a first water wash, using a minimum amount of water,  can  be
drained  into the blood collection system. 18  Bloodwater can be avoided
by installing a blood dryer.  If a plant handles bloodwater,  it  should
not  be  sewered,  but can be rendered, evaporated, or mixed with paunch
and cooked to produce a feed material. ia Blood drying  in  direct  feed
dryers for use as a feed material has been demonstrated on a full scale.
40  Blood  collection  by  a  vacuum system may be a feasible process if
markets for edible blood develop.  Very limited amounts of edible  blood
are collected for pharmacuticals.  In general, improved blood collection
methods  need  to  be  developed  to  match  the high production rate of
American plants.


                                 Paunch

The use of water in the initial dumping of paunch material or in pumping
it must be discontinued.  Dumping the entire paunch contents   (including
the  liquid)  for  disposal or treatment without sewering, followed by a
high pressure but minimal water rinse of the paunch  will  minimize  the
pollutional wasteload from this operation.  Consideration should also be
given  to vacuuming out the residual material instead of washing it out.
In each case the economics of recovery of the paunch  and  cost  of  the
resulting  waste  treatment  should  be  examined and compared to direct
rendering of the paunch, as is.

Liquids screened from  the  paunch  material  should  be  collected  and
evaporated  or  rendered,  not wasted.  Plants that presently slurry the
paunch with water for pumping should either install  a  solids  handling
pump,  thus avoiding the need for a water slurry, or devise an alternate
                                  63

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handling technique; e.g., transporting the  entire  unopened  paunch  to
rendering.


                            Viscera Handling

The  production  necessity of the inedible hashing and washing operation
is subject to conjecture.  Inedible  viscera  can  be  rendered  without
washing.   A  good  quality  grease  may  be obtained if the washings of
edible viscera (i.e., chitterlings) are collected in a  catch  basin  in
the  immediate area before sewering. 1(>  The grease and solids wasteload
from the viscera can be commensurately reduced through  such  by-product
recovery  techniques.   Caustic  washings  from  any  viscera processing
should be segregated before sewering to minimize  grease  saponification
and to avoid a high pH in the waste water.
                                Troughs

Troughs  have  been  installed under the killing floor carcass conveying
line to keep as much blood,  trimmings,  bone  dust,  and  miscellaneous
pieces  off  the  floor  as  possible.   The  troughs  have  proven very
effective in collecting and containing solids, blood, etc.,  that  under
ordinary  circumstances  would  have ended up in the sewer.  Substantial
wasteload reductions are evident in  the  plants  using  these  troughs.
Variations in animal size may be a problem; however, if large variations
are  rare,  some acccmodation should be possible.  A squeegee or scraper
shaped to fit the trough is used  in  clean-up  to  move  all  collected
materials to the inedible rendering system.


                               Rendering

Both  wet  and  dry  rendering are used for edible, as well as inedible,
rendering processes; although the trend is  toward  dry  rendering.    In
processing lard, low^ or medium-temperature continuous rendering systems
are  common.   The water centrifuged from this process can be sold as  50
to 60 percent edible "stickwater" and thus should be evaporated and  not
discharged to the sewer.

In  dry  rendering, sprays are commonly used to condense the vapors.   In
inedible dry rendering, catch-basin effluent can be reused as  condenser
water.   In edible dry rendering, the vapors are commonly condensed with
fresh water.  A direct heat exchanger can be used to condense the vapors
without increasing waste water volumes.

In wet rendering, the greases are drawn off the top of  the  tank,  then
the  water  phase   (tankwater)  is  removed.   This tankwater has a BOD5

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ranging from 22,000 mg/1 to as high as 45,000 mg/1 and suspended  solids
as  high as 2 percent.  Under no circumstances can this type of waste he
discharged to the sewer.  It must be evaporated  and  the  end  product,
commonly  called  stick  or stickwater, is then blended into animal feed
materials.  The tankwater may  also  be  dried  directly  with  inedible
solids in a dry rendering tank.  The bottom sludge from wet rendering is
pressed  for  recovery  of  residual  grease,  and  the remaining solids
(cracklings)  are used as edible product from edible  rendering,  and  as
animal feed ingredient from inedible rendering.

Even if the tankwater is evaporated, pollution can occur.  Triple-effect
vacuum  evaporators  can  readily  foam  over, further contaminating the
waste water.


                            Hide Processing

An overflow of water from the hide curing vat or raceway occurs  because
water  is  added  to  the curing solution and because hides dehydrate as
they take on salt.  This  overflow  could  be  contained  and  collected
separately,  allowing  a more intensive treatment, at a reasonable cost,
to achieve a higher  quality  effluent,  especially  in  terms  of  salt
concentrations.    It  is  especially  important  to  dump  the  raceway
infrequently—perhaps only annually.  When dumped, it should be  drained
gradually,  over a period of 24 hours or more, to avoid an extreme shock
load on the treatment system.  The life of the solution can be  extended
by pumping it over a static or vibrating screen.


                               Scald Tank

The  hog  scald tank contains settled solids and waste water with a high
wasteload.  Collection, treatment, and reuse of  this  water  should  be
considered.  Slow drainage of the tank will reduce any shock load on the
waste  treatment  system  and  should  be  standard practice.  Provision
should be made for the removal of the solids through the bottom  of  the
tank to a truck for land disposal.


                      Pickle and Curing Solutions

These  solutions are high in salt content and, in many curing solutions,
high in sugar content.  Salt is a  difficult  pollutant  to  remove  and
sugar  has  a  very  high  BODS,   The operations involving injection or
soaking of meat products  in  these  solutions  should  be  equipped  to
collect  all  of the solution presently wasted.  The collection pans and
equipment should be designed to permit reuse of these solutions. 10,17
                                  65

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                      Water Conservation Practices

The following practices and equipment should be employed to  reduce  the
water   consumption   in  plants  with  coincidental  reduction  of  the
pollutional wasteload: 10,17

    1.   Replace all drilled spray pipe systems with spray nozzles
         designed and located to provide a desired water spray
         pattern.

    2.   Replace all washwater valves with squeeze- or press-to-
         open valves wherever possible.  Foot- or knee-operated
         valve control is useful where operator fatique is a
         problem or where the operation requires the operator
         to work with both hands.

    3.   Install foot-pedal operated handwashing and drinking
         fountain water valves to eliminate constnatly running
         water.

    4.   Install automatic control for sprays which need to
         operate only about 50 percent of the time.

    5.   Product chillers using cold water may be economically
         replaced by chillers using a cryogenic liquid such as
         nitrogen, thus reducing water consumption and perhaps
         improving product quality.

    6.    The boiler blowdown is potentially reusable and
         should be considered for use in clean-up or in the plant
         laundry.  Detergent use will be reduced as well as water
         conserved.

    7.   Plant clean-up as an operating procedure consumes a
         substantial quantity of water in most plants.  Reduced
         water use can be achieved with equipment such as high
         pressure water spray systems, steam and water mix
         spray systems, or automated clean-in-place  (CIP) systems.
         Management ccntrol is particularly vital in clean-up
         operations if water is to be conserved and cleanliness
         standards are to be maintained.

    8.   Whenever possible, water should be reused in lower
         quality needs.  Examples include carcass washwater
         reused for hog dehairing, and lagoon water reused for
         cooling.  The general axiom is:  use the lowest quality
         of water satisfactory for the process.
                                   66

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                          Clean-Up Operations

In addition to water conservation practices, other  steps  can  also  be
taken  to reduce the wasteload from clean-up:  floors and other surfaces
should be dry squeegeed or scraped wherever feasible, to keep a  maximum
amount  of  solids  and  grease  out of the waste water;  pull the drain
basket only after cleanup has been completed;  use the minimum of  water
and  detergent, consistent with cleaning requirements,  and automate the
cleaning of conveyors, piping and other equipment.
                                  67

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                       IN-PLANT PRIMARY TREATMENT

                           Flow Equalization

Equalization facilities consist of a holding tank and pumping  equipment
designed  to  reduce  the  fluctuations  of  waste streams.  They can be
economically advantageous whether  the  industry  is  treating  its  own
wastes  or  discharging  into a city sewer after some pretreatment.  The
equalizing tank will store waste water either for recycle or reuse or to
feed the flow uniformly to treatment facilities  throughout  the  24hour
day.   The  tank  is characterized by a varying flow into the tank and a
constant flow out.

The major advantages of  equalization  for  the  meat  packer  are  that
treatment systems can be smaller, since they can be designed for the 24-
hour  average  rather than the peak flows, and secondary waste treatment
systems  operate  much  better  when  not  subjected  to  shockloads  or
variations on feed rate.
                                Screens

Since  so  much of the pollutional matter in meat wastes is originally a
solid  (meat particles and fat) or sludge (manure  solids) ,  interception
of  the  waste  material  by various types of screens is a natural first
step.  To assure best operation for application to the plant waste water
stream, a flow equalization facility should precede it.

Unfortunately, when these pollutional materials enter  the  sewage  flow
and are subjected to turbulence, pumping, and mechanical screening, they
break  down  and  release soluble BOD5 to the flow, along with colloidal
and suspended and grease solids.  Waste treatment—that is, the  removal
of soluble, colloidal and suspended organic matters-is expensive.  it is
far  simpler  and  less  expensive  to  keep the solids out of the sewer
entirely.

Static, vibrating, and rotary screens are the  primary  types  used  for
this   step in the in-plant primary treatment.  Whenever feasible, pilot-
scale  studies are warranted before selecting a screen,  unless   specific
operating  data are available for the specific use intended, in  the same
solids concentration range, and under the same operating conditions.
                                   68

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Static gcreens

The primary function of a static screen is to remove  "free"  or  trans-
porting  fluids.   This can be accomplished in several ways and, in most
older concepts, only gravity drainage is involved.  A  concavely  curved
screen  design  using  high  velocity pressure-feeding was developed and
patented in the 1950's for mineral classification and has  been  adapted
to other uses in the process industries.  This design employs bar inter-
ference  to the slurry which knives off thin layers of the flow over the
curved surface. 17

Beginning in 1969, United States and foreign patents were allowed  on  a
three-slope  static  screen made of specially coined curved wires.  This
concept used the Coanda or wall attachment  phenomena  to  withdraw  the
fluid from the under layer of a slurry which is stratified by controlled
velocity over the screen.  This method of operation has been found to be
highly effective in handling slurries containing fatty or sticky fibrous
suspended matter. 17

The  arrangement  of transverse wires with unique singular curves in the
sense of flow provides a relatively non-clogging surface for  dewatering
or screening.  The screens are precisely made in No. 316 stainless steel
and  are  extremely rugged.  Harder, wear-resisting stainless alloys may
also be used for special purposes.  Openings of 0.025 to 0.15 cm  (0.010
to 0.060 inches) meet normal screening needs. *7


yibrating_Screens

The  effectiveness  of  a  vibrating  screen  depends on a rapid motion.
Vibrating screens operate between 900 rpm and 1800 rpm; the  motion  can
either  be circular or straight line, varying from 0.08 to 1.27 cm (1/32
to 1/2 inch)  total travel.  The speed and motion  are  selected  by  the
screen manufacturer for the particular application.

Of prime importance in the selection of a proper vibrating screen is the
application  of  the  proper  cloth.  The capacities on liquid vibrating
screens are based on the percent of open area of the cloth.   The  cloth
is  selected with the proper combination of strength of wire and percent
of open area.  If the waste solids to be handled are heavy and abrasive,
wire of a greater thickness and diameter should be used to  assure  long
life.   However,  if  the  material  is  light  or sticky in nature, the
durability of the screening surface may be the  smallest  consideration.
In  such  a  case, a light wire may be necessary to provide an increased
percent of open area.
                                  69

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Rotary Screens

One type of  barrel  cr  rotary  screen,  driven  by  external  rollers,
receives  the  waste  water at one open end and discharges the solids at
the other open end.   The  liquid  passes  outward  through  the  screen
(usually  stainless  steel  screen  cloth  or  perforated  metal)   to  a
receiving box and effluent sewer mounted below the screen.   The  screen
is  usually  sprayed  continuously  by means of a line of external spray
nozzles.  The screen is usually inclined towards the  solids  exit  end.
This  type  is  popular  as an offal screen but has not been used to any
great extent in secondary "polishing11—that is, in removing solids  from
waste  streams  containing  low  solids concentrations. 17  (A screen of
this type has been developed for recycle of hide brining waters.)

Another rotary screen commonly used in the meat industry is driven by an
external pinion gear.  The raw flow is discharged into the  interior  of
the  screen  below  center, and solids are removed in a trough and screw
conveyor mounted lengthwise at the  center  line  of  the  barrel.   The
liquid  exits  outward through the screen into a box in which the screen
is partially submerged.  The screen is usually 40 x 40 mesh, with 0.4 mm
(1/64 inch) openings.  Perforated lift paddles mounted lengthwise on the
inside surface of the  screen  assist  in  lifting  the  solids  to  the
conveyor  trough.   This  type  is  also generally sprayed externally to
reduce blinding.  Grease clogging can be reduced  by  coating  the  wire
cloth with teflon.  Solids removals up to 82 percent are reported. »7


Applications

A  broad  range  of applications exist for screens as the first stage of
inplant primary treatment processes.  These include both the plant waste
water and waste water discharged from individual processes.  The  latter
include   paunch  manure,  hog  stomach  contents,  hog  hair  recovery,
stickwater solids, hide washing operations, hide curing  brine  recycle,
and others.


                              Catch Bas3.ns

The  catch  basin  for  the  separation  of  grease and solids from meat
packing waste waters was  originally  developed  to  recover  marketable
grease.   Since the primary object was grease  recovery, all improvements
were centered on skimming.  Many catch basins  were  not  equipped  with
automatic  bottom sludge removal equipment.  These basins could often be
completely drained to the sewer and were  "sludged  out"  weekly  or  at
frequencies  such  that  septic conditions would not cause the sludge to
rise.  Rising sludge was undesirable because it could  affect  the  color
and reduce the market value of the grease.
                                   70

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In  the  past  twenty  years, with waste treatment gradually becoming an
added economic incentive, catch basin design has been  improved  in  the
solids  removal area as well.  In fact, the low market value of inedible
grease and tallow has reduced concern about quality  of  the  skimmings,
and now the concern is shifting toward overall effluent quality improve-
ment.   Gravity  grease recovery systems will remove 20 to 30 percent of
the BODS, 40 to 50 percent of the suspended solids and 50 to 60  percent
of the grease (hexane solubles). 1*

The  majority  of  the gravity grease recovery basins  (catch basins)  are
rectangular.  Flow rate is the most important criterion for  design;   30
to  40  minutes  detention time at one hour peak flow is a common sizing
factor. 17  The use of an equalizing  tank  ahead  of  the  catch  basin
obviously  minimizes  the  size  requirement  for  the basin.  A shallow
basin—up to 1.8m  (6 feet)—is preferred.

A "skimmer" skims the grease  and  scum  off  the  top  into  collecting
troughs.    A  scraper  moves  the  sludge at the bottom into a submerged
hopper from which it can be pumped.  Both skimmings and sludge go to by-
product recovery.

Usually two identical catch basins, with a common wall, are desirable so
operation can continue if one is down for maintenance or  repair.   Both
concrete and steel tanks are used.

Concrete tanks have the inherent advantages of lower overall maintenance
and  more  permanence  of  structure.  However, some plants prefer to be
able to modify their operation for future expansion  or  alterations  or
even relocation.

All-steel  tanks  have  the advantage of being semiportable, more easily
field-erected, and more easily modified than concrete tanks.   The  all-
steel tanks, however, require additional maintenance as a result of wear
from abrasion.

A  tank  using  all-steel walls and concrete bottom is probably the best
compromise between the all-steel tank and the  all-concrete  tank.   The
advantages  are  the  same  as  for  steel;  however, the all-steel tank
requires a footing  underneath  the  supporting  members,  whereas,  the
concrete  bottom  forms  the floor and supporting footings for the steel
wall tank.


                        Dissolved Air^Flotation


As a materials recovery concept, dissolved air  flotation  is   actually
functioning to treat wastes.
                                  71

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However within the context of this report,  therefore the effluent from a
dissolved  air flotation system is considered raw waste.  This system is
normally used to  remove  fine  suspended  solids  and  is  particularly
effective on grease in waste waters from meat packing plants.   This is a
relatively  recent  technology  in  the meat industry; however, it is in
fairly widespread use and increasing numbers of  plants  are  installing
these systems.

Dissolved  air  flotation appears to be the single most effective device
that a  meat  packing  plant  can  install  to  reduce  the  pollutional
wasteload  in  its  waste  water stream.  It is expected that the use of
dissolved air flotation will become standard practice in  the  industry,
especially as a step in achieving the 1977 or 1983 standards.


Technical Description

Air  flotation  systems  are  used to remove any suspended material from
waste water with a  specific  gravity  close  to  that  of  water.   The
dissolved  air system generates a supersaturated solution of waste water
and compressed air by raising the pressure of the waste water stream  to
that  of  the  compressed  air, then mixing the two in a detention tank.
This supersaturated mixture of air and waste  water  flows  to  a  large
flotation  tank  where  the  pressure  is  released,  thereby generating
numerous small air bubbles which effect the flotation of  the  suspended
organic  material  by  one  of three mechanisms:  1) adhesion of the air
bubles to the particles cf matter;  2) trapping of the  air  bubbles  in
the  floe  structures  of  suspended  material  as  the bubbles rise; 3)
adsorption of the air bubbles as the floe structure is formed  from  the
suspended  organic  matter.  *8   In  most  cases, bottom sludge removal
facilities are also provided.

There are three process alternatives varying  by  the  degree  of  waste
water  that  is  pressurized and into which the compressed air is mixed.
In the total pressurization process. Figure 12, the entire  waste  water
stream  is  raised  to  full  pressure for compressed air injection.  In
partial pressurization. Figure 13, only a part of the waste water stream
is raised to the pressure of the compressed air for  subsequent  mixing.
In  the  recycle  pressurization  process   (Alternative B of Figure 13),
treated effluent from the flotation tank is recycled and pressurized for
mixing with the compressed air  and  then,  at  the  point  of  pressure
release,  is mixed with the influent waste water.  Alternative A  (Figure
13) shows a side-stream of influent entering the  detention  tank,  thus
reducing  the  pumping  required  in  the  system  shown  in   Figure 12.
Operating costs may vary slightly, but performance should be essentially
equal among the alternatives.
                                  72

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Improved  performance  of  the  air  flotation  system  is  achieved  by
coagulation of the suspended matter prior to treatment.  This is done by
pH adjustment or the addition of coagulant chemicals, or both.  Aluminum
sulfate, iron sulfate, limer and polyelectrolytes are used as coagulants
at varying concentrations up to 300 to UOO mg/1 in the raw waste.  These
chemicals  are  essentially  totally  removed in the dissolved air unit,
thereby adding little or no  load  to  the  downstream  waste  treatment
systems.  Chemical precipitation is also discussed later, particulary in
regard  to  phosphorus removal, under tertiary treatment; phosphorus can
also be removed at this primary  (in-plant)   treatment  stage.   A  slow
paddle  mix  will  improve  coagulation.  It has been suggested that the
proteinaceous matter in meat packing plant waste  could  be  removed  by
reducing  the  waste  water to the isoelectric pH range of about 3.5. 19
The protein material would be  coagulated  at  that  point  and,  readily
removed  as  float  from  the  top of the dissolved air unit.  This is a
typical practice in the meat  industry  in  the  United  States  at  the
present

However, a somewhat comparable practice involving by-product recovery is
gaining  acceptance.   In  this  system,  segregated sewers are required
along with two stages of air flotation treatment of the waste waters.  A
good quality grease product can be recovered from a grease~bearing waste
water without the addition of  chemicals  in  the  first  dissolved  air
system.   The  effluent  from the first dissolved air unit is mixed with
effluent from the other waste streams in the plant and this  is  fed  to
the  second  dissolved  air  unit which may or may not include chemicals
addition, as mentioned above.

One of the manufacturers of dissolved air flotation equipment  indicated
a  60  percent  suspended  solids  removal  and  80 to 90 percent grease
removal without the addition of chemicals.  With the addition of 300  to
400 mg/1 of inorganic coagulants and a slow mix to coagulate the organic
matter,  the  manufacturer says that 90 percent or more of the suspended
solids can be removed and more than 90 percent of the grease.  20  Total
nitrogen  is  also  reduced  as  exemplified  by  the 35 to 70 reduction
efficiencies for the air flotation units for which data  were  available
for this study.

North Star's staff observed the operation of several dissolved air units
during  the  verification  sampling program and other plant visits.  One
plant that was visited controlled the feed rate  and  pH  of  the  waste
water and achieved 90 to 95 percent removal of solids and grease.  Other
plants  had  relatively good operating success, but some did not achieve
the results that should have been attainable.  It appeared that they did
not fully understand the process  chemistry  and  were  using  erroneous
operating procedures.

The Alwatec process has been developed by a company in Oslo, Norway, and
uses  a  lignosulfonic  acid  precipitation and dissolved air flotation.
                                  75

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recovering a high protein product that is valuable as a feed.  21  Nearly
instantaneous  protein  precipitation  and  hence,  nitrogen  removal is
achieved when high protein-containing effluent,  such as that from a meat
packing plant, is acidified to a pH between 3 and U, and high  molecular
weight   fully   sulphonated^  sodium  lignosulphonate  is  added.   BODS
reduction is reported to range from 60 to 95 percent and  the  recovered
protein  material leads to a reduction of nitrogen in the effluent of 85
to 90 percent  The effluent must be neutralized before further treatment
by the addition of milk of lime or some other inexpensive alkali.   This
process  is  being  evaluated  on meat packing waste in one plant in the
United States at the present time.

Problems and Reliability

The reliability of the  dissolved  air  flotation  process  and  of  the
equipment  seems  to  be well established, although it is relatively new
technology for the  meat  packing  industry.   As  indicated  above,  it
appears  that the use of the dissolved air system is not fully exploited
by some of the companies who have installed them for waste water  treat-
ment.   The  potential  reliability  of the dissolved air process can be
realized by proper  installation  and  operation.   The  feed  rate  and
process  conditions must be maintained at the proper levels at all times
to assure this reliability.   This  fact  does  not  seem  to  be  fully
understood  or  of  sufficient  concern to some companies, and thus full
benefit is frequently not achieved.

The sludge and float taken from the dissolved air system can be disposed
of with the sludges obtained from  secondary  waste  treatment   systems.
The  addition  of  polyelectrolyte chemicals was reported to create some
problems for sludge dewatering; however, this may have been  the  unique
experience  of one or tvvo meat packing plants.  The mechanical equipment
involved in  the  dissolved  air  flotation  system  is  fairly  simple,
requiring  standard  maintenance  attention for such things as pumps and
mechanical drives.


                BIOLOGICAL WASTEWATER TREATMENT SYSTEMS

The biological treatment methods commonly used for the treatment of meat
packing wastes after in-plant primary treatment  (solids removal) are the
following biological  systems;  anaerobic  processes,  aerobic   lagoons,
variations  of  the  activated  sludge  process, and high-rate trickling
filters.  Based on operational  data  from  a  pilot-plant  system,  the
rotating  biological  contactor shows potential as a secondary treatment
system.  Several of these  systems are capable  of   providing  70  to  97
percent BODS  reductions and 80 to 95 percent suspended solids reduction,
while  combinations of these systems can achieve  reductions greater than
99 percent in BOD5 and grease, and greater than 97  percent in   suspended
solids.
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The  selection  of  a  secondary biological system for treatment of meat
packing   wastes   depends   upon   a   number   of   important   system
characteristics.   Some of these are waste water volume, equipment used,
pollutant reduction effectiveness  required,  reliability,  consistency,
and  resulting  secondary  pollution problems (e.g., sludge disposal and
odor control).  The characteristics and performance of each of the above
mentioned secondary treatment systems, and also for common  combinations
of them, are described below.  Capital and operating costs are discussed
in  Section VIII.  Since the treatment of wastes does not differ for the
four subcategories of the meat packing industry  (see  Section  IV),  no
distinction by subcategory is made in the following discussion.


                          Anaerobic_Processes

Two  types  of  anaerobic  processes  are  used:   anaerobic lagoons and
anaerobic contact systems.  Elevated temperatures  (29° to 35°C or 85° to
95°F)  and the high concentrations of carbohydrates, fats, proteins,  and
nutrients  typically found in meat packing wastes make these wastes well
suited to anaerobic treatment.  Anaerobic or faculative  microorganisms,
which  function  in  the  absence  of  dissolved  oxygen, break down the
organic wastes to intermediates such  as  organic  acids  and  alcohols.
Methane  bacteria  then  convert  the  intermediates primarily to carbon
dioxide and  methane.   Unfortunately,  much  of  the  organic  nitrogen
present  in  the  influent  is  converted to ammonia nitrogen.  Also, if
sulfur compounds are present  (such as from high-sulfate raw water—50 to
100 mg/1 sulfate) hydrogen sulfide will be generated or acid  conditions
will  develop  which  suppress  methane  production  and  create  odors.
because they provide high overall removal of BOD5 and  suspended  solids
anaerobic  processes  are  economical  with  no  power  cost  (other than
pumping) and with low land requirements.


Anaerobic Lagoons

Anaerobic lagoons are widely used in the industry as the first  step  in
secondary treatment or as pretreatment prior to discharge to a municipal
system.   Reductions of up to 97 percent in BOD5 and up to 95 percent in
suspended solids can be achieved with the lagoons; 85 percent  reduction
in  BOD5  is  common.   A  usual arrangement is two anaerobic lagoons in
parallel, although occasionally two are used in series.   These  lagoons
are  relatively  deep  (3  to  5  meters,  or  about 10 to 17 feet), low
surface-area systems with typical  waste  loadings  of  240  to  320  kg
BOD5/1000  cubic  meters   (15  to  20  Ib  BOD5/1000  cubic  feet) and a
detention time of five to ten days.  A thick scum layer  of  grease  and
paunch  manure is frequently allowed to accumulate on the surface of the
lagoon  to  retard  heat  loss,  to  ensure  anaerobic  conditions,  and
hopefully  to  retain  obnoxious  odors.   Low pH and wind can adversely
affect the scum layer.
                                  77

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Plastic covers of  nylon-reinforced  Hypalon,   polyvinyl  chloride,  and
styrofoam have been used on occasion in place  of the scum layer; in fact
some   states   require  this.    Properly  installed  covers  provide  a
convenient means for pdcr control and collection of methane gas.

Influent waste water flow should be near, but  not on, the bottom of  the
lagoon.   In  some  installations, sludge is recycled to ensure adequate
anaerobic seed for the influent.  The effluent from the lagoon should be
located to prevent short-circuiting the flow and carry-over of the  scum
layer.   For  best  operation,  the pH should be between 7.0 and 8.5.  At
lower pH, methane-forming  bacteria  will  not  survive  and  the  acide
formers  will  take  over  to  produce very noxious odors.  At a high pH
(above 8.5), acid forming bacteria  will  be  suppressed  to  lower  the
lagoon efficiency,


Advantages-Pisadvantages.  Advantages  of an anaerobic lagoon system are
initial low cost, ease of operation, and the  ability  to  handle  large
grease  loads  and  shock  waste  loads,  and  yet continue to provide a
consistent quality effluent.21  Disadvantages of an anaerobic lagoon are
the hydrogen sulfide generated from sulfated waters  and  the  typically
high  ammonia  concentrations  in  the effluent of 100 mg/1 or more.  If
acid conditions develop, sever  odor  problems  result.   If  the  gases
evolved  are  contained,  it  is  possible to use iron filings to  remove
sulfides.


Application. Anaerobic lagoons used as   the  first  stage  in   secondary
treatment "are  usually  followed  by aerobic lagoons.  Placing a  small,
mechanically aerated lagoon between the  anaerobic and aerobip lagoons is
becoming popular.  A number of plants are currently installing  extended
aeration  units following the anaerobic  lagoons to obtain nitrification.
Anaerobic lagoons are not permitted in some states or  areas  where  the
gound  water  is  high  or  the  soil  conditions are adverse  (e.g., too
porous)r or because of odor problems.
                                   78

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Anaerobic Contact^ System

The anaerobic contact system requires far more equipment  for  operation
than  do  anaerobic  lagoons,  and consequently is not as commonly used.
The equipment, as illustrated in Figure  14,  consists  of  equalization
tanks,  digesters  with  mixing  equipment,  air or vacuum gas stripping
units, and sedimentation tanks (clarifiers).  Overall reduction of 90 to
97 percent in BODS and suspended solids is achievable.

Equalized waste water flow is introduced into  a  mixed  digester  where
anaerobic  decomposition  takes  place  at a temperature of about 33° to
35°C  (90° to 95°F).  EOD5 loadings into the digester are between 2.4 and
3.2 kg/cubic meter (0.15 and 0.20 Ib/cubic foot), and the detention time
is between three and twelve hours.  After gas  stripping,  the  digester
effluent is clarified and sludge is recycled at a rate of about onethird
the  raw  waste influent rate.  Sludge at the rate of about 2 percent of
the raw waste volume is removed from the system.7


Advantages-Disadvantages.  Advantages of the  anaerobic  contact  system
are  high  organic  waste  load  reduction  in  a relatively short time;
production and collection of methane gas that can be used to maintain  a
high  temperature in the digester and also to provide auxiliary heat and
power; good effluent stability  to  grease  and  wasteload  shocks;   and
application  in  areas where anaerobic lagoons cannot be used because of
odor or soil conditions.   Disadvantages  of  anaerobic  contactors  are
higher  initial  and  maintenance  costs and some odors emitted from the
clarifiers.


Applications.  Anaerobic contact systems are restricted to  use  as  the
first  stage  of  secondary  treatment  and  can be followed by the same
systems  following  anaerobic  lagoons  or  trickling  filter   roughing
systems.


                            Aerated Lagoons

Aerated  lagoons have been used successfully for many years in a limited
number of installations for treating meat packing wastes.  However, with
recent tightening of effluent limitations and because of the  additional
treatment  aerated  lagoons  can provide, the number of installations is
increasing.

Aerated lagoons  use  either  fixed  mechanical  turbine^type  aerators,
floating propeller-type aerators, or a diffused air system for supplying
oxygen  to  the waste water.  The lagoons usually are 2,4 to 4.6 m  (8 to
15 feet) deep, and have a detention time  of  two  to  ten  days.   BOD5
reductions  range  from  40 to 60 percent with little or no reduction in
                                  79

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suspended solids.   Because of this,  aerated lagoons approach  conditions
similar to extended aeration without sludge recycle (see below).


Advantages-Pisadvantages

Advantages  of  this system are that it can rapidly add dissolved oxygen
(DO)  to convert anaerobic waste waters  to  an  aerobic  state;   provide
additional  BODS  reduction;  and  require  a relatively small amount of
land.  Disadvantages are the power requirements  and  that  the  aerated
lagoon,  in  itself,  usually  does not reduce BODS and suspended solids
adequately to be used as the final stage in a high performance secondary
system,


Applications

Aerated lagoons are usually the second stage of secondary treatment  and
must  be  followed  by  an  aerobic  (shallow) lagoon to capture residual
suspended solids and to provide additional treatment.


                            Aerobic Lagoons

Aerobic lagoons (or stabilization lagoons or oxidation ponds) are  large
surface  area,  shallow  lagoons, usually 1 to 2.3 m  (3 to 8 feet) deep,
loaded at a BODS rate of 20 to 50 pounds per acre.  Detention times will
vary from about one month to six or seven months; thus, aerobic  lagoons
require large areas of land.

Aerobic lagoons serve three main functions in waste reduction:

    o    Allow solids to settle out;

    o    Equalize and control flow;

    o    Permit stabilization of organic matter by aerobic and
         facultative microorganisms and also by algae.

Actually, if the pond is quite deep,  1.8 to  2.4 m  (6  to 8 feet), so that
the  waste  water near the bottom is  void of dissolved oxygen, anaerobic
organisms may be present.  Therefore, settled solids  can  be  decomposed
into   inert  and   soluble  organic   matter  by  aerobic,  anaerobic  or
facultative  organisms,  depending  upon  the  lagoon conditions.   The
soluble  organic  matter  is  also  decomposed by microorganisms.  It is
essential to maintain aerobic conditions in  at least  the upper 6  to  12
inches  in  shallow lagoons since aerobic microorganisms cause the most
complete oxidation  of organic matter.  Wind  action assists  in  carrying
the  upper  layer   of  liquid  (aerated by air-water interface and photo-
                                  80

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synthesis)  down into the deeper portions.  The  anaerobic  decomposition
generally  occuring  in  the  bottom  converts solids to liquid organics
which can become nutrients for the aerobic organisms in teh upper zone.

Algae growth is common in aerobic lagoons; this currently is a  drawback
when  aerobic  lagoons  are  used for final treatment.  Algae may escape
into the receiving waters, and the algae added to receiving  waters  are
considered a pollutant.  Algae in the lagoon, however, play an important
role  in  stabilization.   They use CO2, sulfates, nitrates, phosphates,
water and sunlight to synthesize their own organic cellular  matter  and
give   off   free  oxygen.   The  oxygen  may  then  be  used  by  other
microorganisms for their metabolic processes.  However, when  algae  die
they  release  their  organic  matter in the lagoon, causing a secondary
loading.  Lagoon discharge p^pes located about 30 cm or 1 foot below the
lagoon surface will help reduce the algae content in the effluent.

Ammonia disappears without the appearance of  an  aquivalent  amount  of
nitrite  and  nitrate  in aerobic lagoons.  From this, and the fact that
aerobic lagoons tend to become anaerobic near  the  bottom,  it  appears
that some denitrification is occurring.

Ice  and  snow  cover  in  winter  reduces  the overall effectiveness of
aerobic lagoons by  reducing  algae  activity,  preventing  mixing,  and
preventing  reaeration  by  wind  action  and diffusion.  This cover, if
present for an extended period,  can  result  in  anaerobic  conditions.
When there is no ice and snow cover on large aerobic lagoons, high winds
can  develop  a  strong  wave  action  that  can  damage dikes.  Riprap,
segmented lagoons, and finger dikes are used  to  prevent  wave  damage.
Finger dikes, when arranged appropriately, also prevent short circuiting
of  the  waste  water  through the lagoon.  Rodent and weed control, and
dike maintenance are all essential for good operation of the lagoons.


Adyantages^Disadyantacies

Advantages of aerobic lagoons are that they reduce suspended solids, and
colloidal matter  remaining  in  aerated  chamber  or  anaerobic  lagoon
effluents,  oxidize  organic matter, permit flow control and waste water
storage.  Disadavantages are reduced effectiveness during winter months,
the large land requirements, the algae growth  problem,  ineffectiveness
in  removing  residual  grease,  and  odor  problems for a short time in
spring, after the ice melts and before the lagoon becomes aerobic again.
                                  81

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Applications

Aerobic lagoons usually are the last stage in  secondary  treatment  and
frequently follow anaerobic or anaerobic-aerated lagoons.  Large aerobic
lagoons  allow plants to store waste waters for discharge during periods
of high flow in the receiving body of water or to store  for  irrigation
purposes  during  the summer.  These lagoons are particularly popular in
rural areas where land is available and relatively inexpensive.


                            Activated Sludge

The conventional activated sludge  process  is  schematically  shown  in
Figure  15.  In this process recycled biologically active sludge or floe
is  mixed  in  aerated  tanks  or  basins  with   waste   waters.    The
microorganisms  in  the  floe  adsorb organic matter from the wastes and
convert it by oxidation-enzyme systems to such stable products as carbon
dioxide, water, and sometimes nitrates and sulfates.  The time  required
for  digestion  depends  on the type of waste and its concentration, but
the average time is six hours.  The floe, which is a mixture  of  micro-
organisms  (bacteria,  protozoa, and filamentous types), food, and slime
material, can assimilate organic matter rapidly when properly activated;
hence, the name activated sludge.

From the aeration tank the mixed liquor waste waters,  in  which  little
nitrification  has  taken place, are discharged to a sedimentation tank.
Here the sludge settles cut, producing a clear effluent, low in BOD5,
and a biologically active sludge.  A  portion  of  the  settled  sludge,
normally  about  20  percent, is recycled to serve as an inoculum and to
maintain a high mixed liquor suspended solids content.  Excess sludge is
removed  (wasted) from the system, usually to  thickeners  and  anaerobic
digestion,  or  to  chemical  treatment  and dewatering by filtration or
centrifugation.
                                  83

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This conventional activated sludge process can reduce BODS and suspended
solids up to 95 percent.  However, because it cannot readily handle  the
shock loads and widely varying flow common to meat packing waste waters,
this  particular  version  of  activated  sludge  is not a commonly used
process for treating meat packing wastes.

Various  modifications  of  the  activated  sludge  process  have   been
developed,   such  as  the  tapered  aeration,  step  aeration,  contact
stabilization, and  extended  aeration.   Of  these,  extended  aeration
processes are being used for treatment of meat packing wastes.


Extended _Aeration

The  extended  aeraticn process is similar to the conventional activated
sludge process, except that the mixture  of  activated  sludge  and  raw
waste  water is maintained in the aeration chamber for longer periods of
time.  The common detention time in extended aeration is  one  to  three
days,  rather than six hours.  During this prolonged contact between the
sludge and raw waste, there is ample time for the organic matter  to  be
adsorbed  by  the  sludge  and  also for the organisms to metabolize the
organic matter which they have adsorbed.  This allows for a much greater
removal of  organic  matter.   In  addition,  the  organisms  undergo  a
considerable  amount  of  endogenous  respiration, and therefore oxidize
much of the organic matter which has been built up into  the  protoplasm
of  the  organism.  Hence, in addition to h;Lgh organic removals from the
waste  waters,  up  to  75  percent  of  the  organic  matter   of   the
microorganisms  is decomposed into stable products and consequently less
sludge will have to be handled.

In extended aeration, as in the conventional activated  sludge  process,
it  is necessary to have a final sedimentation tank.  Some of the solids
resulting from extended aeration are rather finely divided and therefore
settle slowly, requiring a longer period of settling.

The long detention time in the extended aeration tank makes it  possible
for  nitrification to occur.  In nitrification under aerobic conditions,
ammonia is converted to nitrites and  nitrates  by  specific  groups  of
nitrifying  bacteria.  For this to occur, it is necessary to have sludge
detention times in excess of ten days.21  This can  be  accomplished  by
regulating  the  amounts of sludge recycled and wasted each day.  Oxygen
enriched gas could be used in place of air  in  the  aeration  tanks  to
improve  overall performance.  This would require that the aeration tank
be partitioned and covered, and that the air compressor  and  dispersion
system be replaced by a rotating sparger system, which costs less to buy
and  operate.  When cccurrent, staged flow and recirculation of gas back
through the liquor is employed, between 90 and 95 percent oxygen use  is
claimed. 22  Although this modification of extended aeration has not been
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used  in treating meat packing wastes,  it is being used successfully for
treating other wastes.


Advantages and Pis advantages

The advantages of the extended aeration process are that it is stable to
shock loading and flow fluctuations because the incoming raw waste  load
is  diluted,  by the liquid in the system, to a much greater extent than
in conventional activated sludge.   Also, because of the  long  detention
time,  high  BOD5  reductions  can be obtained.  Other advantages of the
system are  the "elimination  of  sludge  digestion  equipment  and  the
capability  to  produce a nitrified effluent.  Disadvantages are that it
is difficult to remove most of  the  suspended  solids  from  the  mixed
liquor  discharged  from the aeration tank; large volume tanks or basins
are required to accommodate the  long  detention  times;  and  operating
costs for aeration are high.


Applications

Because  of  the  nitrification  process,  extended aeration systems are
being used following anaerobic lagoons  to  produce  low  BODS  and  low
ammonia- nitrogen effluents.  They are also being used as the first stage
of secondary treatment followed by polishing lagoons.


                            Tricklinc?
A  trickling  filter  consists of a bed of rock or prefabricated plastic
filter media on the surface of which the  microbial  flora  develops;  a
rotary  arm  waste  water  distribution  system;  and  an under-drainage
system.  The distribution arm uniformly distributes waste water over the
filter media. The microflora adsorbs,  and  eventually  metabolizes  the
organic  matter  in  the  liquid  as it trickles down through the media.
When the growth becomes fairly thick it begins to slough off the surface
of the media as large pieces of solids which are carried with the liquid
out through the  under-drainage  system.   Consequently,  the  trickling
filter  must  be followed by an appropriate sedimentation tank to remove
the solids.  To avoid clogging the trickling  filter,  the  waste  water
must  be pre-treated  (primary, in-plant treatment) to remove most solids
and grease.

The high-rate trickling filter is used  in  treating  meat  plant  waste
waters  either  as  a roughing filter preceding a conventional secondary
treatment such as activated sludge or as complete secondary treatment in
several stages.  Hydraulic loading for high rate  trickling  filters  is
generally  in the range of 93.5 to 187 million liters per hectare  (10 to
20 million gallons per acre) per day.
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In treating high organic  wastes  with  trickling  filters  there  is  a
definite  limit  to BODS removal by a single stage.  Common practice has
been to use a multistage filter system.  The first stage filter  can  be
fed at a BOD5 rate of 0.016 to 0.024 kg/cubic meter of media (100 to 150
pounds/1000  cubic  feet)  and can result in 40 to 50 percent removal of
BODS.  If the second stage filter is the final filter to  be  used,   the
loading should not exceed 0.4 kg BODS/cubic meter of media (25 pounds of
BODS  per  1000 cubic feet)  of media.  However, since the raw waste load
of meat packing plants is relatively strong, this may mean that the size
of the second filter will be excessively large.  In this case, it  might
be better to provide still a third stage; then loadings can be higher in
the  second stage--up to 0.8 to 1.2 kg BODS per cubic meter of media (50
to 75 pounds of BOD5/1000 cubic feet of  media).   The  loading  to  the
third  stage  should  be limited to 0.32 kg of BODS/cubic meter of media
(20 pounds/1000 cubic feet).  The overall removal of such a  system  can
be  as high as 95 percent reduction in BODS.  When staging of filters is
used, it is desirable tc provide a sedimentation tank  for  each  stage.
However,  large rock cr synthetic media can be used without intermediate
sedimentaton.  Because of the size of second and third stage filters and
because of the number of sedimentation tanks that may be required,  this
system  is  no  longer  generally  used  in  the  meat packing industry.
Although single-stage filters alone result  in  considerably  less  BODS
reduction  than  staged trickling filter systems, they have found use in
the meat industry, particularly as a pretreatment prior to some type  of
activated sludge system.


Advantages^and^Disadvantages

Advantages  of  the roughing trickling filter are that it can smooth out
hydraulic and BODS loadings; provide some initial reduction in BODS  (40
to  50  percent);  and  the  fact  that  it is not injured materially by
extended rest periods such as weekends.  However, if there are long rest
periods it is desirable to  recirculate  the  effluent  of  one  of  the
settling  tanks  through  the  filter  to  keep the floe moist.  Another
advantage of the roughing filter is its reliability  with  minimum  care
and attention,  A disadvantage of the trickling filter system in general
is  that  it is a costly installation, it may also be necessary to cover
the  filters  in  winter  to  prevent  freeze-up,   and   the   effluent
concentration fluctuates with changes in incoming wasteload.
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                     Rotating Biological contactor

Process Description

The  rotating biological contactor (RBC)  consists of a series of closely
spaced flat parallel disks which are rotated while partially immersed in
the waste waters  being  treated.    A  biological  growth  covering  the
surface  of  the  disk  adsorbs  dissolved organic matter present in the
waste water.   As the biomass on the disk  builds  up,  excess  slime  is
sloughed  off  periodically  and is removed in sedimentation tanks.  The
rotation of the disk carries a thin film of waste  water  into  the  air
where  it  absorbs  the  oxygen  necessary  for  the  aerobic biological
activity of the biomass.   The  disk  rotation  also  promotes  thorough
mixing  and  contact  between the biomass and the waste waters.  In many
ways the RBC system is a compact version of a trickling filter.  In  the
trickling  filter the waste waters flow over the media and thus over the
microbial flora; in the RBC system, the  flora  is  passed  through  the
waste water.

The  system  can  be  staged  to  enhance overall waste water reduction.
Organisms on the disks selectively develop in each stage  and  are  thus
particularly adapted to the composition of the waste in that stage.  The
first  couple  of  stages might be used for removal of dissolved organic
matter, while the latter stages might be  adapted  to  nitrification  of
ammonia.


D eve 1 opmen t ^ St a tus

The  RBC  system  was  developed  independently in Europe and the United
States about 1955  for  the  treatment  of  domestic  waste,  but  found
application  only  in  Europe.   Currently,  there are an estimated 1000
domestic installations in Europe.21  However, the use of the RBC for the
treatment of meat packing waste is relatively new.  The only operational
information available on its use on meat packing waste was obtained on a
pilot-scale system, although a large installation was recently completed
at the Iowa Beef Processors plant in  Dakota  City,  Nebraska,  for  the
further  treatment  of  meat  packing  waste effluents from an anaerobic
lagoon.  The pilot-plant studies were conducted with  a  four-stage  RBC
system with four-foot diameter disks.  The system was treating a portion
of the effluent from the Austin, Minnesota, anaerobic contact plant used
to  treat  meat  packing  waste.   These results showd a BOD5 removal in
excess of 50 percent with loadings less than 0.037 kg BODS on an average
BODS  influent  concentration  of  approximately  25  mg/1.   Data  from
Autotrol Corporaton revealed ammonia removals of greater than 90 percent
by  nitrification  in  a multistage unit.  Four to eight stages of disks
with maximum hydraulic loadings of 61 liters per day  per  square  meter
 (1.5 gallons per day per square foot) of disk area are considered normal
for ammonia removal.
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Advantages ^and^Disadyantaqes

The  major advantages of the RBC system are its relatively low installed
cost; the effect of staging to  obtain  both  dissolved  organic  matter
reduction and removal of ammonia nitrogen by nitrification; and its good
resistance  to hydraulic shock loads.  Disadvantages are that the system
should be housed, if located in cold climates, to maintain high  removal
efficiencies,   to   control   odors,  and  to  minimize  problems  with
temperature sensitivity.  Although  this  system  has  demonstrated  its
durability  and reliability when used on domestic wastes, it has not yet
been fully tested to treat meat packing plant wastes.


Uses

Rotating biological contactors could be  used  for  the  entire  aerobic
secondary  system.  The number of stages required depends on the desired
degree of treatment and the influent strength.  Typical applications  of
the  rotating  biological  contactor,  however, may be for polishing the
effluent from anaerobic processes and from  roughing  trickling  filters
and  as  pretreatment prior to discharging wastes to a municiapl system.
A BODS reduction of 98 percent is achievable with a four-stage RBC.2*


          Performance^f Various Biological Treatment Systems

Table  6  shows  BODS,  suspended  solids  (SS),  and   grease   removal
efficiencies for various biological treatment systems used to treat meat
packing  waste  waters.   Average  values are presented for ten systems;
exemplary values for five systems.  Exemplary values each represent  one
system   (except for anaerobic plus aerobic lagoons, where they represent
two systems)  considered to be among the best for that kind of system and
whose values were actually verified in the  field  sampling  study  con-
ducted during this program.

The  number  of  systems used to calculate average values, also shown in
Table 6, clearly shows that the anaerobic plus aerobic lagoons  are  the
most commonly used.  In fact this system was used by about 63 percent of
the  plants included in the study that reported having secondary systems
(see Section VIII).

The estimated value  of  BODS  shown  for  the  anaerobic  lagoons  plus
rotating  biological  contactor is based upon pilot-plant results and is
considered to be conservative.

The values shown for the anaerobic lagoons plus  extended  aeration  are
also  estimated and are all below the values calculated by using average
removal efficiencies for the two components of the system  individually.
For  example,  if  the  BODS reduction for both the anaerobic lagoon and
                                  89

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extended aeration were 90 percent, the calculated efficiency  of the  two
systems combined would be 99.0  percent
                   Table 6.  Performance of Various Secondary
                            Treatment Systems.
Secondary Treatment System
(number of systems used
to determine averages)
Anaerobic + Aerobic
lagoon (22)
Anaerobic + aerated +
Aerobic lagoon (3)
Anaerobic Contact Process +
Aerobic lagoon (1)
Extended Aeration +
Aerobic lagoon (1)
Anaerobic lagoon + Rotating
Biological contactor
Anaerobic lagoon + Extended
Aeration + Aerobic lagoon
Anaerobic lagoon +
Trickling filter (1)
2-Stage Trickling filter (1)
Aerated + Aerobic
lagoon (1)
Anaerobic Contact (1)
Water Wasteload Reduction
Average Values
BOD 5
95.4
98.3
93.5
96.0
98. 5e
98e
97.5
95.5
99.4
96.9
SS
93.5
93.3
96.0
86.0
—
93e
94.0
95.0
94.5
97.1
Grease
95.3
98.5
99.0
98.0

98e
96.0
98.0
—
95.8
Exemplary Values
BOD 5
98.9
99.5

96.0




99.4
96.9
SS
96.6
97.5

86.0




94.5
97.1
Grease
98.9
99.2

98.0




—
95.8
       e - estimated
                                   90

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                    TERTIARY AND ADVANCED^TREATMENT


                  Chemical Precipitation of Phosphorus


Phosphorus is an excellent nutrient for algae and thus can promote heavy
algae  blooms.   As  such it cannot be discharged into receiving streams
and its concentration should not be allowed to build  up  in  a  recycle
water  stream.   However,  the  presence  of  phosphorus is particularly
useful in spray irrigation or land utilization systems as a nutrient for
plant growth.

The  effectiveness  of  chemical  precipitation.  Figure  16,  is   well
established  and  has  been verified in full scale during the North Star
verification sampling program.  One packing plant operates  a  dissolved
air  flotation system as a chemical precipitation unit and achieves a 95
percent phosphorus removal to a  concentration  of  less  than  1  mg/1.
Chemical  precipitation  can be used for primary  (in-plant) treatment to
remove BOD5, suspended solids,  and  grease,  as  discussed  earlier  in
conjunction  with  dissolved  air  flotation.  Also, it can be used as a
final treatment follcwing  biological  treatment,  to  remove  suspended
solids in addition to phosphorus.


Technical^Description

Phosphorus  occurs  in waste water streams from packing plants primarily
as phosphate salts.  Phosphates can be precipitated with trivalent  iron
and  trivalent  aluminum  salts.  It can also be rapidly precipitated by
agglomeration of the precipitated colloids and by the settling  rate  of
the agglomerate.18  Laboratory investigation and experience with inplant
operations  have  substantially  confirmed  that  phosphate  removal  is
dependent on pH and that this removal tends to be limited by the optimum
pH for the iron and aluminum precipitation occurs in the U to  6  range,
whereas  the  calcium  precipitation  occurs  in the alkaline side at pH
values above  9.5.18  Coincident  with  the  phosphate  removal  is  the
efficient  removal  of suspended solids which are cleaned from the water
in the flocculant.

Since  the  removal  of  phosphorus  is  a  two-step  process  involving
precipitation  and  then  agglommerationr  and both are sensitive to pH,
setting the pH level takes on added significance.  if a  chemical  other
than  lime  is used in the precipitation-coagulation process, two levels
of  pH  are  required.   Precipitation  occurs  on  the  acid  side  and
coagulation  is  best carried out on the alkaline side.  The precipitate
is removed by sedimentation or by dissolved air flotation.18
                                  91

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Polyelectrolytes are polymers that can be used  as  primary  coagulants,
flocculation  aids, filter aids, or for sludge conditioning.  Phosphorus
removal may be enhanced by the use of such polyelectrolytes by producing
a better floe than might occur without such chemical addition.23

The chemically precipitated sludge contains grease and organic matter  in
addition to the phosphorus, if the system is used in primary  treatment.
If  it  is used as a post-secondary treatment, the sludge volume  will  be
less and it will contain primarily phosphorus salts.   The  sludge   from
either treatment can be landfilled without difficulty.
                                                   Float
or
Treatment
PH
Ajustment
X

Chemical
Addition
X

Air
Flotation
System
partial
x. ^fcptifii»tf
	 • • ^ icriiury
— I Treated
                                                       Sludge
                                                          to
                                                       Disposal
                      Figure 16.  Chemical Precipitation
Development Status

This   process   is well-established  and understood technically.  Although
its use on meat industry waste  is very limited,  it is gaining acceptance
as a primary waste  treatment  process.   Where it is in use, it  is  being
operated  successfully  if  the process chemistry is understood and the
means  to control the  process  are available.
 Problems
                                   92

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As indicated above, the reliability of this process is well  established;
however, it is a chemical process and as such  requires   the   appropriate
control  and operating procedures.  The problems that can  be encountered
in operating this process are those caused by  a lack of  understanding  or
inadequate equipment.  Sludge disposal is not  expected to  be a   problem.
The   use  of  polyelectrolytes  and  their  effect  on  the dewatering
properties of the sludge are open to some question at the  present time.
                              Sand^Filter

A slow sand filter is a specially prepared bed  of  sand  or other  mineral
fines  on which doses of waste water are intermittently applied and  from
which effluent is removed by an under-drainage   system,   Figure  17;   it
removes  solids  from  the  waste  water  stream.    BOD5  removal occurs
primarily as a function of the degree of solids removal,  although  some
biological  action occurs in the top inch or two of  sand.   Effluent  from
the sand filter is of a high quality  with  BOD5  and   suspended  solids
concentrations  of  less  than 10 mg/1.2*  Although  the performance  of a
sand filter is well known and  documented,  it   is  not  in  common   use
because it is not needed to reach current waste water standards.

A  rapid  sand filter functions as the  slow sand filter but operation is
under pressure in a closed vessel or  may  be   built in  open  concrete
tanks.   It is primarily a water treatment device  and thus would be  used
as tertiary  treatment,  following  secondary   treatment.    Mixed media
filters  are  special  versions of rapid sand filters that permit deeper
bed-penetration by gradation of particle  sizes in  the  bed.    Up-^flow
filters are also special cases of rapid filters.


                                           Chlorination,
                                             Optional
   Primary or
   Secondary
    Effluent
                                           for Odor Control
                                     v
                                 Surface 0  Back
                                  Clean     Wash
                                  to Regenerate
                                                              > Treated
                                                              Effluent
                 Figure 17.   Sand Filter System
                                   93

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Technical Description

The  slow  sand  filter  removes  solids primarily at the surface of the
filter.   The rapid sand filter is operated to allow a deeper penetration
bof suspended solids into  the  sand  bed  and  thereby  achieve  solids
removal  through  a  greater  cross-section  of  the  bed.    The rate of
filtration of the rapid filter is up to  100  times  that  of  the  slow
filter.    Thus,  the  rapid filter requires substantially less area than
the slow filter; however, the cycle time  averages  about  2U  hours  in
comparison  with cycles of up to 30 to 60 days for a slow filter.25  The
larger area required for the latter means  a  higher  first  cost.   For
small  plants,  the slow sand filter can be used as secondary treatment.
In larger sizes, the labor in maintaining and cleaning the  surface  may
operate against its use.  The rapid sand filter on the other hand can be
used  following  secondary treatment, but would tend to clog quickly and
require frequent automatic backwashing if used as  secondary  treatment,
resulting in a high water use.  This washwater would also need treatment
if the rapid sand filter is used following conventional solids removal.

The  rapid  filters  operate  essentially  unattended with pressure-loss
control and piping installed for automatic  backwashing.   They  may  be
enclosed in concrete structures or in steel tanks.23


Clean-up  of  the  rapid  sand filter requires backwashing of the bed of
sand with a greater quantity of  water  than  used  for  the  slow  sand
filter.   Backwashing  is  an  effective clean-up procedure and the only
constraint is to minimize the washwater required  in  clean-up  as  this
must be disposed of in some appropriate manner other than discharging it
to a stream.


Develop_ment__status

The slow sand filter has been in use for 50 years and more.  It has been
particularly  well suited to small cities and isolated  treatment  systems
serving hotels, motels, hospitals, etc., where treatment of low flow  is
required  and   land and sand are available.  Treatment  in these applica-
tions has been  a  sanitary-  or  municipal-type  raw  waste.   The  Ohio
Environmental   Protection  Administration   is  a strong advocate  of slow
sand filters as a secondary treatment for small meat  plants,  following
some  form  of  settling  or  solids removal.  As of early 1973,  16 sand
filters had been installed and   8  were  proposed  and  expected  to  be
installed.   All  24  of  these  installations were on waste from  packing
plants.26  The  land  requirements  for  a  slow  sand  filter  are  not
particularly   significant  in  relation  to those required for lagooning
purposes in secondary treatment  processes.   However,   the  quality  and
quantity of sand is important and may be a  constraint in the use  of sand
filters  in  some  local  situations.  It should also be recognized that

-------
this process requires hand labor for raking the crust that  develops  on
the  surface.   Frequency  of raking may be weekly or monthly, depending
upon the degree of previous treatment and the gradation of the sand.


Problems

The reliability of the slow sand filter seems to be well established  in
its  long-term use as a municipal waste treatment system.  When the sand
filter is operated intermittently  there  should  be  little  danger  of
operating  mishap with resultant discharge of untreated effluent or poor
quality effluent.  The need for bed cleaning becomes  evident  with  the
reduction  in  quality  of  the effluent or in the increased cycle time,
both of which are subject to monitoring and control.  Operation in  cold
climates  is  possible  as  long  as  the  appropriate adjustment in the
surface of the bed has been made to  prevent  blockage  of  the  bed  by
freezing  water.   Chlorination,  both  before and after sand filtering,
particularly in the use of rapid filters, may be desirable  to  minimize
or eliminate potential odor problems and slimes that may cause clogging.

The  rapid  sand  filter  has  been  used extensively in water treatment
plants and in municipal sewage treatment for  tertiary  treatment;  thus
its  use  in tertiary treatment of secondary treated effluents from meat
plants appears to be a practical method of reducing BOD5  and  suspended
solids  to  levels  below  those  expected  from  conventional secondary
treatment.
                        Microscreen-Microstrainer

A microstrainer is a filtering device that uses a fine mesh screen on  a
partially submerged rotating drum to remove suspended solids and thereby
reduce   the   BOD5  associated  with  those  solids,  Figure  18.   The
microstrainer is used as a tertiary treatment following the  removal  of
most  of  the  solids from the waste water stream.  The suspended solids
and BODS can be reduced to 3 to 5 mg/1 in municipal systems.  19   There
are  no  reports  of  their  use in the tertiary treatment of meat plant
wastes.
Secondary
Treotrnpnt ^
Effluent
Micro-
Screen
\
f
Ba<

skwash
Clear

to
Sere

ten/Strainer
Tertiary
Treated
Effluent
                   Figure 18.  Microscreen/Microstrainer

                                  95

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Technical Description

The microstrainer is a filtration device  in  which  a  stainless  steel
microfabric  is  used  as the filtering medium.   The steel wire cloth is
mounted on the periphery of a drum which is rotated partially  submerged
in  the  waste  water.   Backwash  immediately follows the deposition of
solids on the fabric, and in  one  installation,  this  is  followed  by
ultraviolet  light  exposure  to  inhibit microbiological growth.*«  The
backwash water containing the solids amounts to about 3 percent  of  the
waste  water  stream  and  must  be  disposed  of  by  recycling  to the
biological treatment system.28  The drum is rotated at a minimum of  0.7
and  up to a maximum of 4.3 revolutions per minute.*9  The concentration
and percentage  removal  performance  for  microstrainers  on  suspended
solids and BODS appear to be approximately the same as for sand filters.


Deyelopment_Status

While  there  is  general  information  available  on the performance of
microstrainers and on tests involving the use of them, there appears  to
be  only one recorded installation of a microstrainer in use on municipal
waste; the requirements for effluent quality have not necessitated  such
installation.    The  economic  comparisons  between  sand  filters  and
microstrainers are inconclusive; the mechanical equipment  required  for
the  microstrainer may be a greater factor than the land requirement for
the sand filter at the present time.


Problems and Reliability

The test performance of the microstrainer fairly  well  establishes  the
reliability  of the device in its ability to remove suspended  solids and
the associated BOD?>.  Operating and maintenance problems have  not  been
reported; this is probably because, in large part, of the limited use of
the  device  in  full-scale  applications.   As  a mechanical  filtration
device requiring a  drive  system,  it  would  have  normal  maintenance
requirements  associated  with  that kind of mechanical equipment.  As  a
device based on microopenings in a  fabric,  it  would  be  particularly
intolerant to any degree of grease loading.


                     Nitrificatign-Denitr^fication

This  two-step  process of nitrification and denitrification.  Figure 19,
is a system to remove the  nitrogen which appears as ammonia  in  treated
meat  plant waste waters,  and it is of ,primary  importance for  removal of
the ammonia generated in anaerobic secondary treatment  systems.  Ammonia
removal  is becoming more important because of stream  standards being set
                                   96

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at levels as low as 1 to 2  mg/1.7   Removal  of  ammonia
complete, with the nitrogen gas as the end product.
                                is  virtually
Technical Description

The  large  quantities  of organic matter in raw waste  from  meat packing
plants is frequently and effectively treated in anaerobic  lagoons.   Much
of the nitrogen in the organic matter, present  mainly   as  protein,   is
converted  to  ammonia  in  anaerobic  systems or  in  localized  anaerobic
environments.  The following sets of equations indicate the nitrifica-
tion of the ammonia to nitrites and nitrates, followed  by  the subsequent
denitrification  to  nitrogen  and  nitrous  oxide.28    The  responsible
organisms are indicated also.
rur nui
Secondary .
Treatment
Effluent
Aeration
System

>w
/
^ ^
Anaerobic
Pond



Aeration
Cell

Tertiary
> Treatea
Effluent
                          Carbon
                          Source,
                        e.g. Methanol
               Figure 19.   Nitrification/Denitrification
Nitrification:
         NH3 + 02
N02- + H30+
   (Ni tro somona s)
         2NO2- +02
2N03-
(Nitrobacter)
    Denitrification  (using methanol  as  carbon  source)

         6H+ + 6NO_- + 5CH_OH         5CQ2  + 3N2  +  13  H20

         Small amounts of  N2O  and  NO  are   also   formed
                   heterotrophs)
                                  (Facultative
Nitrification  does  not  occur  to   any   great extent until most of the
carbonaceous material has been removed  from the waste water stream.   The
ammonia  nitrification  is  carried   out   by   aerating   the   effluent
                                   97

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sufficiently  long  to  assure the conversion of all the nitrogen in the
raw effluent  to  the  nitrite-nitrate  forms  prior  to  the  anaerobic
denitrification step.

The  denitrification  step, converting nitrates to nitrogen and nitrogen
oxides, takes place in the absence of oxygen.  It is thought to  proceed
too slowly without the addition of a biodegradable carbon source such as
sugar,  ethyl  alcohol, acetic acid, or methanol.  Methanol is the least
expensive and performs satisfactorily.  Investigators  working  on  this
process  have  found  that  a  30  percent  excess  of methanol over the
stiochiometric amount is required.23,30

In current waste treatment practice using anaerobic and aerobic lagoons,
ammonia nitrogen that disappears in the aerobic system does not show  up
to  a  large  extent as nitrites and nitrates.  Ammonia stripping is not
likely to account for the loss.  It appears  that  denitrification  must
actually  be  occurring  in  the  bottom reaches of the aerobic lagoons,
where anaerobic conditions are probably approached.

Presuming total conversion of the ammonia to nitrites or nitrates, there
will be virtually no nitrogen remaining in the  effluent  from  the  de-
nitrification  process.   Total nitrogen removal can be maintained at 90
percent over the range of operating  temperatures;  the  rate  increases
with  temperature  to  an  optimum  value of approximately 30°C for most
aerobic waste systems.  Temperature increases beyond  30°  result  in  a
decrease in the rate for the mesophilic organisms.28

The  waste  water  is  routed  to  a second aeration basin following de-
nitrification,  where  the  nitrogen  and  nitrogen  oxide  are  readily
stripped  from the waste stream as gases.  The sludge from each stage is
settled and recycled to preserve the organisms required for each step in
the process.


Development Status

The specific nitrification-denitrification process has  been carried out
successfully at the bench- and  pilot-scale  levels.   Gulp  and  Culp23
suggest that the "practicality of consistently maintaining the necessary
biological reactions and the related economics must be demonstrated on a
plantdeveloped  at  the  Cincinnati Water Research Laboratory of the EPA
and is being  built  at  Manassas,  Virginia.31   This  work  and  other
demonstrated  useful   concepts  are   reported  in a recent EPA technical
booklet. *7 As mentioned above, observations of  treatment  lagoons  for
meat  packing  plants  gives some  indication  that the  suggested reactions
are occurring in   present  systems.   Also,  Halvorson32  reported  that
Pasveer ^.s achieving  success in denitrif ication  by carefully controlling
the reaction rate  in an oxidation ditch, so  that dissolved oxygen levels
drop  to zero just  before the water is reaerated  by the next rotor.
                                   98

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Problems and^Reliability

In  view  of  the  experimental status of this process, it would be pre-
mature to speculate on the reliability or problems incumbent in a  full-
scale  operation.   It  would appear that there would be not exceptional
maintenance or residual pollution problems associated with this  process
in view of the mechanisms suggested for its implementation at this time.

                           Ammonia Stripping

Ammonia  stripping  is a modification of the simple aeration process for
removing gases in water. Figure 20.  Following pH adjustment, the  waste
water  is  fed  to  a  packed tower and allowed to flow down through the
tower with a countercurrent air stream introduced at the bottom  of  the
tower flowing upward to strip the ammonia.  Ammonia-nitrogen removals of
up  to  98  percent  and down to concentrations of less than 1 mg/1 have
been achieved in experimental ammonia stripping towers.23


Technical^Description

The pH of the waste water from a secondary treatment system is  adjusted
to  between 11 and 12 and the waste water is fed to a packed tower or to
a cooling tower type of stripping tower.  As pH is shifted above  9  the
ammonia  is  present as the soluble gas in the waste water stream rather
than as the ammonium ion.30  Ammonia-nitrogen removal of 90 percent  was
achieved  with countercurrent air flows between 1.8 and 2.2 cubic meters
per liter (250 and 300 cubic feet per  gallon)  of  waste  water  in  an
experimental  tower  with  hydraulic loadings between 100 and 125 liters
per minute per square meter (2.5 and 3 gallons  per  minute  per  square
foot).   A  maximum  of 98 percent ammonia removal was reported with the
air rate at 5.9 cubic meters per liter  (800 cubic feet per gallon) and a
hydraulic loading of 33 liters per minute per square meter  (0.8  gallons
per  minute  per square foot).  The ammonia concentration was reduced to
less than one  part  per  million  at  98  percent  removal.   The  high
percentage removal of ammonia-nitrogen is achieved only at a substantial
cost  in  terms  of air requirements and stripping tower cross sectional
area.23

Because the system involves  the  stripping  of  ammonia  from  a  water
stream,  ambient  air  temperatures  below 0°C  (32°F) present a problem;
operation in cold climates may require  housing  inside  a  building  or
heating  of the air prior to introducing it to the stripping tower.  The
residual pollution would be the ammonia stripped from  the  waste  water
stream  and  concentration  of ammonia in the air stream prior to mixing
with the ambient_ air would be  about  10  milligrams  per  cubic  meter „
whereas  the  threshhold  for  odor  is  about  35  milligrams per cubic
meter.23
                                  99

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Development Status

The ammonia stripping process is a well-established  industrial   practice
in the petroleum refinery industry.  The only significant  difference
between  petroleum refinery application and that on  a meat packing  plant
waste would probably be the comparatively small size of  stripping  tower
for  the  meat  packing  plants  in comparison to the refinery.   The air
stripping of ammonia from secondary effluent is reported primarily  on an
experimental basis in equipment that is 1.8 meters  (6 feet)  in   diameter
with a packing depth of up to 7.3 meters  (21 feet).  Two large
    Secondary
    Treatment
    Effluent
   pH
Adjustment
Ammonia
Stripping
  Tower
                                  Air
                                 Blowers
                                     Treated
                                     Effluent
                      Figure 20.  Ammonia Stripping
scale installations  of  ammonia  stripping of lime treated waste water are
reported  at   South  Tahoe,  California,  and Windhoek, South Africa.23r118
The  South Tahoe  ammonia stripper  was rated at  iH.2  M  liters  per  day
 (3.75  MGD) and  was  essentially constructed as a cooling tower structure
rather than as a cylindrical steel tower which might be used in  smaller
sized plants.

Thus,  although   there   is   no  reported use of ammonia stripping on meat
packing plant  waste,  the technology is  well established and  implementa-
tion, when standards require it,  should be without difficulty.


Problems and Reliabiility

The  reliability  of  this  process has  been established by the petroleum
refinery uses  of the process over many  years.  Although  the  source  of
                                   100

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the  ammonia may be different and there may be other contaminants in the
water stream, none of this should affect the established reliability  of
this  process.    The  experience of other users of the process will have
pretty  well  identified  potential  problems,  and,   presumably,   the
solutions  for  these  problems.   The maintenance requirements would be
only those normally associated with the mechanical equipment involved in
pumping the waste water to the top of  the  tower,  where  the  feed  is
introduced  to the tower, and in maintaining the air blowers.  The tower
fill would undoubtedly te designed for the kind of service  involved  in
treating a waste water stream that has some potential for fouling.

                         Spray/Flood Irrigation

A  no  discharge level for meat packing waste can be achieved by the use
of spray or flood irrigation of  relatively  flat  land,  surrounded  by
dikes  which  prevent  run-off  and  upon which a cover crop of grass or
other vegetation is maintained.  Waste Water  disposal  is  achieved  by
this method to the level of no discharge.  Specific plant situations may
preclude the installation of irrigation systems; however, where they are
feasible, serious consideration should be given to them.


Technical Description

Wastes  are  disposed  of  in  spray or flood irrigation systems by dis-
tribution through piping and spray nozzles over relatively flat  terrain
or  by  the pumping and disposal through the ridge and furrow irrigation
systems which allow a certain level of flooding on a given plot of land,
Figure 21.  Pretreatment for removal of solids is advisable  to  prevent
plugging  of the spray nozzles, or deposition in the furrows of a ridge-
and-furrow system, or collection of solids on  the  surface,  which  may
cause  odor  problems  or  clog  the  soil.   Therefore,  the BOD5 would
undoubtedly have already been reduced in the  preliminary  treatment  in
preparation for distribution through the spray system.


In  a flood irrigation system the waste loading in the effluent would be
limited by the waste loading tolerance  of  the  particular  crop  being
grown  on  the  land,  or  it  may  be limited by the soil conditions or
potential for vermin or odor problems.
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Waste Water distributed in either manner percolates through the soil and
the organic matter in the waste undergoes a biological degradation.  The
liquid in the waste stream is either stored in the soil or leached to  a
groundwater  aquifer and discharges into the groundwater.  Approximately
10 percent of the waste flow will be  lost  by  evapotranspiration   (the
loss  caused  by  evaporation  to  the  atmosphere through the leaves of
plants) . 28
Primary,
Secondary
or
Dnrtinl — — ^i
Tertiary
Treatment
Effluent

Holding
Basin

N-


Pumping
System

^


Application
Site


                                                     Grass or
                                                     Hay Crop
                Figure 21.  Spray/Flood Irrigation System
Spray runoff irrigation  is  an  alternative  technique   which  has   been
tested  on  the waste  from a small meat  packer39  and  on  cannery waste.*0
With this technique, about 50 percent  of the waste water applied to  the
soil  is  allowed  to  run off as a discharge rather than no discharge as
discussed here.  The runoff or discharge from  this  type  of  irrigation
system  is  of higher  quality than the waste water as applied,  with BOD5
removal of about 80 percent, total organic carbon and ammonia   nitrogen
are  about  85  percent  reduced, and  phosphorus  is about 65 percent re-
duced. 39

The following factors  will affect the  ability  of  a particular land   area
to  absorb  waste water:  1) character of the  soil, 2) stratification of
the soil profile, 3) depth to groundwater, U)  initial moisture   content,
5) terrain and groundcover.28

The  greatest  concern  in the use of  irrigation  as a disposal  system is
the total dissolved solids content and particularly the  salt content  of
the waste water.  A maximum salt content of  0.15  percent is suggested in
Eckenfelder.28   In  order  to  achieve   this   level  of  salt content, 30
                                   102

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percent of the total  waste  water  stream  from  a  typical  plant  was
determined  to require treatment in an ion exchange system upstream from
the spray irrigation system.

An application rate of 330 liters per minute per hectare (35 gallons per
minute per acre)  has been recommended in  determining  the  quantity  of
land  required  for various plant sizes.  This amounts to almost 5 cm (2
inches)  of moisture per day and is relatively  low  in  comparison  with
application  rates  reported by Eckenfelder for various spray irrigation
systems.  However, soils vary widely in their percolation properties and
experimental irrigation of a small area is recommended before a complete
system is built.   In many areas, rates as low  as  one-fourth  inch  per
acre  per  day  are  prerequisite  for  conservative, long term disposal
requirements.

The economic benefit from spray irrigation is estimated on the basis  of
raising  one  crop  of  grass hay per season with a yield of 13.4 metric
tons of dry matter per hectare  (six tons per acre) and values at $22 per
metric ton  ($20 per ten).  These figures are conservative  in  terms  of
the  number of crops and the price to be expected from a grass hay crop.
The supply and demand sensitivity as well as transportation problems for
moving the hay  crop  to  a  consumer  all  mitigate  against  any  more
optimistic estimate of economic benefit.29

Cold climate uses of spray irrigation may be subject to more constraints
and  greater  land  requirements than plants operating in more temperate
climates.  However, a meat packer in  Illinois  reportedly  operated  an
irrrigation  system  successfully.  Eckenfelder also reports that wastes
have been successfully disposed of by spray irrigation from a number  of
other industries.

North  Star  found  in  its  survey  that the plants located in the arid
regions of the southwest were  most  inclined  to  use  spray  or  flood
irrigation systems.


Problems and Reliability

Th  long-term  reliability  of  spray  or  flood irrigation systems is a
function of the ability of the soil to continue to accept the  waste  as
it  is  disposed  of through the irrigation system, and thus reliability
remains  somewhat  open  to  question.   Problems  in  maintenance   are
primarily  in  the  control  of  the  proper  dissolved solids level and
salinity content  of  the  waste  water  stream  and  also  in  climatic
limitations that may exist or develop.  Many soils are improved by spray
irrigation.
                                  103

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                              Iont Exchange

Ion  exchange,  as a tertiary waste treatment,  is used as a deionization
process in which specific ionic species are removed from the waste water
stream. Figure 22.  Ion exchange would be used to  remove  salt  (sodium
chloride)   from  waters.  Ion exchange resin systems have been developed
to remove  specific  ionic  species,  to  achieve  maximum  regeneration
operating  efficiency,  and  to  achieve a desired effluent quality.  In
treating meat packing waste, the desired effluent  quality  is  a  total
waste  water  salt  concentration of 300 mg/1.   Ion exchange systems are
available that will remove up to 90 percent  of  the  salt  in  a  water
stream. 19  They can also be used to remove nitrogen.


Technical Description

The  deionization  of  vater by means of ion exchange resin involves the
use of  both  cation  and  anion  exchange  resins  in  sequence  or  in
combination to remove an electrolyte such as salt. l9
              RSO3 + NaCl*   	9RSO3Na + NCI
              R-OH + HC1	*R-C1 + H2O
where R represents the resin


The  normal practice in deionization of water has been to make the first
pass through a strong acid column, cation exchange resin, in  which  the
first  reaction  above occurs.  Effluent from the first column is passed
to a second column of anion exchange resin to remove the acid formed  in
the  first  step,  as indicated in the second reaction.  As indicated in
the two reactions, the sodium chloride ions have been removed  as  ionic
species.   A  great  variety  of ion exchange resins have been developed
over the years for specific deionization objectives  for  various  water
quality conditions.
                                   104

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Waste Water treatment with ion exchange resins has been investigated and
attempted for over 40 years; however, recent process developments in the
treatment  of  secondary  effluent  have been particularly successful in
achieving high quality effluent  at  reasonable  capital  and  operating
costs.   One  such process is a modification of the Rohm and Haas, Desal
process. 19  In this process a weak base ion exchange resin is converted
to the bicarbonate form and the secondary effluent  is  treated  by  the
resin to convert the inorganic salts.  After the first step, the process
includes a flocculation/aeration and precipitation step to
sand  filter  and/or  carbon  adsorption  system is used upstream of the
process is regenerated with aqueous ammonia and the cation resin with an
aqueous sulfuric acid.  The resins did not appear to be  susceptible  to
fouling  by  the  organic constituents of the secondary effluent used in
this experiment.
         Partial
        Tertiary
       Treatment
        Effluent
                                                 Tertiary
                                                 Treated
                                                 Effluent
                            Ion
                         Exchange
                         Column (s)
                                       A
A
      Backwash  8
       Regenerant
        System
                     Figure 22.  Ion Exchange
Other types of resins can be used for nitrate and phosphate  removal,   as
well  as color bodies, COD, and fine suspended matter.  Removal  of  these
various constituents can range from 75 percent to 97  percent.

The cycle time on the ion exchange unit will be  a function of  the  time
required  to block or to take up the ion exchange sites available in  the
resin contained in the system.  Blockage occurs  when  the resin is fouled
by suspended matter and other contaminants.  The ion  exchange system   is
                                   105

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ideally  located  at  the end of the waste water processing scheme,  thus
having the highest quality effluent available as a feedwater.    The   ion
exchange system needed for irrigation purposes (mentioned earlier)  based
on  an  assumed  inlet  salt concentration of 2000 mg/1,  was required to
treat 30 percent of the waste water stream.  This inlet concentration is
fairly  conservative,  based  on  the  North  Star  survey  data.   Salt
concentration  should  be  easily  reduced  to 1000 mg/1 and less with a
minimal effort at controlling salt discharge into the waste water.

To achieve a recyclable water quality, it may be assumed that less  than
500  mg/1  of  total dissolved solids would have to be achieved.  Of the
total dissolved solids, 300 mg/1 of salt are assumed to  be  acceptable.
To  achieve  this  final effluent quality, 95 percent of the waste water
stream would be subjected to ion exchange treatment.

The residual pollution will be that resulting from regeneration  of  the
ion  exchange  bed.   The  resin  systems  as  indicated earlier, can be
tailored  to  the  ion  removal  requirements  and  efficient   use   of
regeneration   chemicals   thus   minimizing   liquid  wastes  from  the
regeneration step.


Development Status


Ion exchange as a unit operation is well established and  commonly  used
in   a   wide  range  of  applications  in  water  treatment  and  water
deionization.  Water softening for boiler feed  treatment  and  domestic
and  commercial  use is probably the most widespread use of ion exchange
in water treatment.  Eeionization of water by ion exchange  is  used  to
remove   carbon  dioxide;  metal  salts  such  as  chlorides,  sulfates,
nitrates,  and  phosphates;  silica;  and  alkalinity.   Specific  resin
applications such as in wastewater treatment have not been widespread up
to  the  present  time, as there has not been a need for such a level of
treatment.  However, process  development  and  experimental  work  have
shown  the  capability  of ion exchange systems to achieve the levels of
salt removal required for the suggested irrigation and closed-loop water
recycle systems examined in this report.

Part of the economic success of  an  ion  exchange  system  in  treating
packing  plant  waste  will  probably  depend on a high quality effluent
being available as a feed material.  This again, can be provided  by  an
upstream treatment system including carbon adsorption or sand filtration
to  remove  a  maximum  of the particularly bothersome suspended organic
material.  However, the affect of a low quality feed would be  primarily
economic  because of shorter cycle times, rather than a reduction in the
overall effectiveness of the ion exchange system in removing a  specific
ionic species such as salt.
                                   106

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Problems and Reliability

Inasmuch  as ion exchange is widely used, the reliability of the concept
is well  established.   The  application  of  the  technology  in  waste
treatment  has  not  been  tested  and therefore the reliability in that
application has yet to be firmly established.  The  problems  associated
with  ion  exchange  operations would primarily center on the quality of
the feed to the ion exchange system and its effect on  the  cycle  time.
The  operation and control of the deionization-regeneration cycle can be
totally  automated,  which  would  seem  to  be  the  desired  approach.
Regeneration  solution  is used periodically to restore the ion exchange
resin to its original state for continued use.  This  solution  must  be
disposed  of  following its use and that may require special handling or
treatment.  The relatively small quantity of  regenerant  solution  will
facilitate its proper disposal by users of this system.


                           Carbon_Adsorption

Carbon  adsorption is a unit operation in which activated carbon adsorbs
soluble and trace organic matter from waste water  streams.  Figure  23.
Either granular or powdered activated carbon can be used to remove up to
98  percent of colloidal and dissolved organics measured as BODS and COD
in a waste water stream. 30  The organic molecules  which  make  up  the
organic  material  attach  themselves  to  the  surface of the activated
carbon and are thereby removed.  Larger  particles  should  be  filtered
from   the  waste  water  in  treatment  systems  upstream  from  carbon
adsorption since the effectiveness of the latter will  be  substantially
reduced  by  gross  particles  of  organic matter.  Total organic carbon
removal efficiencies cf about 50 to 55 percent have  been  reported  for
carbon  adsorbers and 15 to 50 percent removal of soluble organic carbon
is reported, 118 Carbon adsorption treatment of meat packing waste would
be required only if a closed  loop  water  recycle  system  were  to  be
installed with a requisite low organic concentration.
                                  107

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Technical Description

Activated  carbon  in  a  granular  or  powdered form provides an  active
surface for the attachment and resultant removal  of  organic  molecules
from  waste  water streams.  This is a surface adsorption phenomenon  and
is not preferential for any particular molecule.  Thus, in   addition   to
trace  organic  matter, odors and color bodies will also be  removed from
the waste water stream by carbon adsorption.  The rate of adsorption   is
controlled  by the rate of diffusion of the organic molecules within  the
capillary pores of the carbon particles.   This  rate  varies  inversely
with  the  square of the particle diameter and increases with increasing
concentration of organic matter and with  increasing  temperature.    The
implication  of  the  particle  diameter-adsorption rate relationship is
that the smaller the carbon particle the larger the adsorption rate will
be, in any given system.  This factor is the basis for the   interest   in
powdered activated carbon in preference to granular carbon.  «3
     Partial Tertiary
       Treatment  -
        Effluent
Adsorption
  Column
                                 Carbon
                            Regeneration and
                                 Storage
Tertiary
Treated
Effluent
                     Figure 23.  Carbon Adsorption
The  granular  carbon  is  effectively   used   in   packed or expanded bed
adsorbers.  A number cf  processes have been experimentally attempted  to
utilize powdered carbon  in various  process systems such as the fluidized
bed  and  carbon-tef fluent slurry systems.  Regeneration of the carbon is
periodically   required,.    A   standard  regeneration   technique   is
incineration  of  the  organic  matter   deposited  on the surface of the
carbon.  It is economically important  to  regenerate  and  recover  the
carbon  and  regeneration  has  been  a  serious limitation to the use of
powdered activated carbon up to the present time.
                                   108

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Carbon adsorption will remove up to about 98 percent  of  the  colloidal
and  dissolved  organic  matter with resulting effluent COD's down to 12
mg/1 in any of the various physical systems devised for contacting
activated carbon and waste water.  This is  a  finishing  treatment  for
waste  water  intended  to  remove the trace organic material left after
standard secondary and partial tertiary treatment.  Essentially  all  of
the  gross organic particles must be removed from the waste water before
entering this treatment system, 23

The residual pollution associated with carbon adsorption  will  be  that
caused  by  regeneration  and  a  properly  operated  low oxygen furnace
achieving complete combustion of the organic matter  should  present  no
pollution problem for the surrounding air environment.


Deye ^Lopment., Status

Activated  carbon treatment in water purification is common practice and
well established.  Several large scale  pilot  projects  testing  carbon
adsorption  as  a  treatment of waste waters are presently underway.  In
addition, carbon towers have been used  for  the  removal  of  suspended
solids  in  a small number of municipal treatment systems requiring high
quality effluent.  The treatment has not been  applied  specifically  to
meat  packing plant effluent; however, at the point in a waste treatment
system where an activated carbon system would be used, there  should  be
no  significant  difference  between  municipal  waste  and meat packing
waste.  The effluent should be of high quality.

The primary question demanding the attention of  research  investigators
in  the  use of this system is to find an economic method for the use of
activated carbon in pcwdered form rather than granular form.


Problems and Reliabi1ities

Since this  technology  is  well  established  in  the  water  treatment
industry,  it  presumably  can  be  operated  with  the  proper  type of
feedstream on an efficient and reliable basis.  While the  treatment  of
waste  water  for  this  system  is largely limited to large scale pilot
projects, the reliability  and  utility  of  such  treatment  should  be
clearly established within a relatively short time, certainly before the
need for equipment to meet 1983 standards.

Operating  and  maintenance  problems  do  not  seem  to be significant,
particularly  if  the  quality  of  the  feedwater  is   maintained   by
appropriate  upstream  treatment systems.  Regeneration is no problem in
the packed and expanded bed systems and presumably can be worked out for
powdered carbon systems before the mid 1980's.
                                  109

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                            Reverse Osmosis

The reverse osmosis  process  uses  semipermeable  membranes   to   remove
contaminants  dovm  tc  molecular  size,  Figure  24.   It is  capable  of
removing  divalent  icns  at  efficiencies  of  up  to  98  percent and
monovalent  ions  and  small  organic  molecules at 70 to 90 percent.  33
Total solids concentrations between  25  mg/1  and  65  mg/1   have  been
obtained  in  reverse osmosis effluent. 33  Reverse osmosis would not  be
needed for applications other than a closed loop recycle  water   system.
The  application  of  reverse  osmosis  to  date  has  been  limited  to
capacities no larger than 190,000 liters  (50,000 gallons) per  day.


Technical Descriptjon

Several different kinds of semipermeable membranes are available  for use
in the reverse osmosis process.   Data  are  available  on  the   use  of
cellulose  acetate  membranes.   These and other semipermeable membranes
are more permeable to pure water than to dissolved salt and  other  ions
and  molecules.   The  process  operates by reversing the normal  osmotic
process  by  increasing  the  pressure  on  the  side  of  the membrane
containing  the  contaminated  water  until pure water flows through the
membrane from the contaminated side to the pure water  side.   Excellent
rejection or removal of essentially all contaminants in a waste water
Partial
Tertiary
Treatment
Effluent
C\ >
AA *
Pressure
Pump
Reverse
Osmosis
System

»w

J
                                                       Full Tertiary
                                                         Treated
                                                         Effluent
                                         Concentrated
                                           Brine to
                                           Disposal
                       Figure 24.  Reverse Osmosis
                                   110

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stream  from  a  meat  packing plant would be achieved through a reverse
osmosis system.  However, the rate at which pure water would be produced
is still unacceptably low  for  economic  application  of  this  system.
Current  development  work  is aimed at improving the rate at which pure
water can be produced, while retaining the high quality of the effluent.


Development Status
•'•• 	 —I,   1^    L .

The application of reverse osmosis  to  the  treatment  of  waste  water
streams  has  been confined to experiments on domestic sewage on a small
scale.   As  a  waste  treatment  process,  the  limited   capacity   of
commercially  available units and the high operating costs tend to limit
the potential applicability of reverse osmosis waste water treatment  in
the near future.
Problems^and Reliability
The reliability of reverse osmosis remains open to question until larger
scale  and  longer  term  experiments have been conducted on waste water
treatment.  The two operating problems that persist in  reverse  osmosis
are  maintaining  flux  cr  water  purification rates and the relatively
short operating life of  the  membranes.   Another  significant  problem
remains  in  the  bacterial  growth  that  has  been observed on reverse
osmosis membranes, which seriously reduces their  operating  efficiency.
Microbial  growth  has also been observed in the support structure under
the membranes.  Chlorine cannot be used because the membranes which  are
presently  available  are  damaged by chlorination. i9  Research on these
operating problems is continuing, including membrane research  at  North
Star  Research  Institute,  where  new membranes are being developed and
tested.  For example, a new North Star membrane, NS-1, which  is  formed
on   the  surface  of  a  porous  poly sulf one  support  material,  is  a
noncellulosic  membrane  which  has   significantly   better   operating
characteristics than irost membranes currently available.
Electrodialysis  is  a  process that uses an applied electric current to
separate ionic species  in  a  solution.  Figure  25.   Membranes  allow
specific  ions  to  pass  from the waste water stream on one side of the
membrane to a highly concentrated solution of contaminants on the  other
side  of  the  membrane.   Electrodialysis  is  used to remove dissolved
solids such as salt, which is of particular  concern  in  meat  industry
waste.  Single-pass removal efficiencies of up to UO percent of the salt
are the reported performance of the system. 30
                                  111

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Technical Description

The  electro-dialysis  process  incorporates a number of chambers made by
alternating anionic and cationic membranes that are arranged between two
electrodes.  A brine solution  is  alternated  with  contaminated   waste
water   solution  in  the  chambers  between  the  differing  membranes.
Electric current is applied across the  membrane  chambers  causing the
cations  to  move  towards the cathode and the anions towards the  anode.
However, after passing from the chambers containing the waste water into
adjacent brine chambers, the ions  can  travel  no  further  toward the
electrodes.   Their path is blocked by a membrane that is impermeable to
that particular ionic species.  In this manner, the waste  water   stream
is  depleted  while  the  adjacent  brine stream is enriched in the ions
which are to be removed.

Power costs limit  the  salinity  of  the  effluent  waste  water   after
treatment in the electrodialysis system to approximately 300 to  500 mg/1
of  salt.  34  This  limitation  is  imposed  because of the increase  in
electrical resistance in the treated waste water  that  would  occur   at
lower concentrations of salt.
Partial
Tertiary ^
Treatment
Effluent
Electro -
dialysis
System



\
f
                                                        Full Tertiary
                                                          Treated
                                                          Effluent
                                            Concentrated
                                              Brine  to
                                              Disposal
                          Figure 25.  Electrodialysis
 Development Status

 The   residual   pollution from an  electrodialysis unit would be the brine
 solution used and generated in the  chambers of  the  unit.    This  brine
 solution  might be   handled  by  a  blowdown  system  which removes the
 quantity of salt added per unit of   time.    Electrodialysis  is  an  old
                                   112

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process  and  in  fairly  widespread  use  for  the purpose of desalting
brackish water, 34  The treatment  of  waste  water  in  electrodialysis
systems  has not been done except on an experimental basis.  There is no
reported application of  the  process  on  waste  water  from  the  meat
industry  which  tends  to  have a fairly substantial salt content.  The
potential utility of the process is therefore speculative as to its  use
on  waste water, however, its widespread use in water desalting suggests
that, if the need arises for its application, it is technically feasible
to desalt waste water in such a process.


Problems and^Reliabjlity

The reliability of the electrodialysis  system  in  removing  salt  from
waste  waters  is  only  speculative  based  on the use of the system in
desalting brackish waters.  It has demonstrated its reliability  in  the
desalting  application.  The problems associated with using this process
in treating waste water from meat  packing  plants  is  the  substantial
cost,  the  necessity  cf brine disposal, and the bacterial growth which
occurs on the dialysis membranes, *8  Chlorine cannot be applied because
it damages the membranes.
                                  113

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                              SECTION VIII

              COST, ENEFGY, AND NON^WATER QUALITY ASPECTS

                                Summary.

The waste water from meat packing plants is  amenable  to  treatment  in
secondary  and tertiary v/aste treatment systems to achieve low levels of
pollutants  in  the  final  effluent.   In-plant  controls,   by-product
recovery operations, and strict water management practices can be highly
effective  in  reducing  the  wasteload  and  waste  water flow from any
industry plant.   These  water  management  practices  will  reduce  the
requisite  size  of secondary and tertiary treatment systems and improve
their waste reduction effectiveness.

The waste treatment investment for a  typical  plant  in  each  industry
sufccategory  is  listed  in Table 7 to achieve each of four successively
increased degrees of treatment:
         A - reduction of organics by the use of anaerobic plus aerated
             plus aerobic lagoon treatment systems,
         B - in-plant controls plus partial tertiary treatment.
         C - no discharge via land disposal by irrigation.
         D - waste water recycle.
The costs reported in Table 7 are  based  on  the  assumption  that  the
average  plant  in  each  subcategory  has  anaerobic plus aerobic waste
treatment lagoons or the equivalent, already installed.  The  costs  are
therefore  the total incremental investment costs required to go to each
stage from the present treatment systems, described above.  These  costs
are  primarily  a function of total waste water flow.  The average daily
flow used for each sutcategory is as follows:

         Simple slaughterhouse - 1.17 M liters/day (0.310 MGD)
         Complex slaughterhouse - 4.35 M liters/day  (1.16 MGD)
         Low-Processing packinghouse - 3.4 M liters/day  (0.85 MGD)
         High-Processing packinghouse - 4.4 M liters/day  (1.2 MGD)

Treatment "A" comprises the three  lagoon  treatment  system—anaerobic-
aerated-aerobic  lagocns—or  its equivalent as the means to achieve the
reduction of the organic load to the 1977 guideline.   The typical  plant
in  each  of  the  four  industry  subcategories  has  adequate in-plant
facilities-usually a catch basin—to  preclude  the  need  for  in-plant
additions in stage "A".

Treatment  "B" incorporates improved in-plant practices and the addition
of a dissolved air flotation unit along with an ammonia removal step and
sand filtering, or the equivalent, in addition to treatment system  "A".
These  treatment  systems  are  applicable  to  plants  in  any  of  the
subcategories.  The organic loading and total waste water flow will vary
                                  115

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both within and between  subcategories; however,  these factors  influence
treatment  system  sizing   rather  than  applicability,  as  indicated in
Section  IV.

Treatment "C" is the  irrigation alternative  and includes   the  treatment
achieved in "A", plus dissolved air flotation,  ion exchange  on a part of
the  waste water stream, chlorination, and the  irrigation  system.  Total
dissolved solids are  a limiting factor in  water  for  irrigation;  thus
plants in the "high-*processing packinghouses" subcategory, which exhibit
a high average chloride  content in the raw waste (Chapter  5)  may need to
devote special attention to it.

Treatment  "D"  comprises   all  of  the  treatment techniques presumably
required to produce a recyclable waste water stream of potable  quality.
These  technologies   can be used by all  of the  subcategories if they are
effective for any one of them.
          Table 7.   Total Investment Costs Per Plant for Upgrading Present
                   Waste Treatment System to Each Stage of Treatment
Effluent
Quality
A
B
C
D
Simple
Slaughterhouse
$ 80,000
425,000
268,000
733,000
Complex
Slaughterhouse
$ 139,000
665,000
487,000
1,315,000
Low-Processing
Packinghouse
$ 131,000
629,000
451,000
1,227,000
High-Processing
Packinghouse
$ 148,000
736,000
544,000
1,475,000
       *Locker plants were,not included in any subcategory, but were assumed to require an
       investment of $10,000 each to go to no discharge by 1977, which appears to be the
       most attractive choice other than municipal treatment.
                                     116

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The annual operating  costs  for  a  treatment  system  to  achieve  the
indicated  effluent  quality  are  reported  in  Table  9.  The costs to
achieve treatment level "A" range from 12 to 21 cents per head of  beef,
depending  on the sutcategory.  The costs to achieve treatment level "B"
vary from $0.90 to $1.50 per head  more  than  present  waste  treatment
costs.   Costs above present for level "C" are about two-thirds of those
for level "B", and costs for level D are nearly twice  those  for  level
"B".

Energy  consumption  associated  with  waste water treatment in the meat
industry is not a serious constraint, varying from 10 to 40  percent  of
present  power  consumption.   The  higher percentage is for the smaller
packing plants that consume  relatively  small  quantities  of  electric
energy at the present time.

With  the  implementation  of  these standards, land becomes the primary
waste sink instead of air and water.  The waste to be land  filled  from
packing  plants  can  improve soils with nutrients and soil conditioners
contained in the waste.  Odor problems can be avoided or  controlled  in
all treatment systems.


                            "TYPICAL" PLANT

The  waste  treatment  systems  applicable  to waste water from the meat
packing industry can te used by plants in all four subcategories of  the
industry,   A  hypothetical  "typical"  plant  was  constructed  in each
subcategory as a basis for estimating investment and total annual  costs
for   the  application  of  each  waste  treatment  system  within  each
subcategory.  The costs  were  estimated,  and,  in  addition,  effluent
reduction,  energy  requirements,  and  non^water quality aspects of the
treatment systems were determined.
                                  117

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The waste treatment systems are applied on the basis  of  the  following
plant configurations for each subcategory:
Industry Subcategory \

Kill, kg LWK/day
(Ib LWK/day)
Waste Water flow
liters/1000 kg LWK
(gal/1000 Ib LWK)
Raw waste, BODS
kg/1000 kg LWK
(lb/1000 Ib LWK)
Processed meat
production
kg/day
(Ib/day)
Simple
Slaughter-
house
220,000
(484,000)
5,328
(639)
6.0
(6.0)
0
Complex
Slaughter-
house
595,000
(1,310,000)
7,379
(885)
10.9
(10.9)
0
Low-
Processing
Packing-
house
435,000
(900,000)
7,842
(941)
8.1
(8.1)
54,000
(119,000)
High-
Processing
Packing-
house
350,000
(800,000)
12,514
(1,500)
16.1
(16.1)
191,000
(422,000)
basis of responses to the North Star questionnaire as follows:
Plant
Small
Medium
Large
TOTAL
Simple
65.456
33.9
0.7
100.0
Complex
0%
50
50
100.0
Low- Process ing High-Processing
63. OX
27.2
9.8
100.0
0%
17.3
82.7
100.0
Total
50.4*
39.0
10.6
100.0
Locker plants are not included in this tabulation.
kill are related as fellows:

    Small - less than 11.4 MM kgs/year  (25 MM Ib)
     Medium - 11.4 to 91 MM kg/year  (25-200 MM Ib)
    Large -» greater than 91 MM kg/year  (200 MM Ib)
Plant size and annual
                                   118

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                 Table 8.  Estimated Total Investment Cost
                           to the Industry to Achieve a Given
                           Level of Effluent Quality from
                           Present Level of Treatment
Effluent
Quality
A
B
C
D
Total Industry
Investment ,
($ millions)
52.8*
159.7
119.0
252.2
Investment
Cost per
million kg LWK
per year
2,355
7,119
5,306
11,240
Investment
Cost per
million Ib LWK
per year,
1,069
3,232
2,409
5,103
*Includes $10,000 per plant for 2600 locker plants,  totaling  $26 million.
        Table 9.  Total Increase in Annual Cost of Waste Treatment,
                  $/1000 kg  ($/1000 Ib) LWK.
Effluent
Quality
A
B
C
D
Simple
Slaughterhouse
0.35
(0.16)
2.93
(1.33)
2.00
(0.91)
4.74
(2.15)
Complex
Slaughterhouse
0.26
(0.12)
1.92
(0.87)
1.34
(0.61)
3.17
(1.44)
Low-Processing
Packinghouse
0.33
(0.15)
2.44
(1.11)
1.74
(0.79)
4.30
(1.95)
High-Pr o c es s ing
Packinghouse
0.46
(0.21)
3.37
(1.53)
2.42
(1.10)
5.62
(2.55)
                                  119

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             Table  10.  Waste Treatment Systems,  Their Use
                        and Effectiveness
       Treatment
        System
     Use
   Effluent Reduction
Dissolved air flotation
(DAF)
DAF with pH control and
flocculants added
Anaerobic + aerobic
lagoons
Anaerobic + aerated +
aerobic lagoons
Anaerobic contact
process
Activated sludge
Extended aeration
Anaerobic lagoons +
rotating biological
contactor
Chlorination


Sand filter,

Microstrainer


Electrodialysis
Ion exchange
Ammonia stripping
Carbon adsorption
Chemical precipitation

Reverse osmosis


Spray irrigation

Flood irrigation

Ponding and evaporation
Primary treatment
or by-product
recovery

Primary treatment
or by-product
recovery

Secondary treatment
Secondary treatment

Secondary treatment

Secondary treatment
Secondary treatment
Secondary treatment
Finish and
disinfection

Tertiary treatment &
Secondary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment


Tertiary treatment


Tertiary treatment

No discharge

No discharge

No discharge
Grease, 60% removal, to
  100 to 200 mg/1
BOD5, 30% removal
SS, 30% removal
Grease, 95-99% removal,
BOD5, 90% removal
SS, 98% removal

BOD , 95% removal
BOD , to 99% removal
BOD , 90-95% removal
BOD , 90-95% removal
BOD , 95% removal

BOD , 90-95% removal
BOD5, to 5-10 mg/1
SS, to 3-8 mg/1
BOD5, to 10-20 mg/1
SS, to 10-15 mg/1

TDS, 90% removal
Salt, 90% removal
90-95% removal
6005, to 98% removal as
  colloidal & dissolved
  organic
Phosphorus, 85-95% removal
  to 0.5 mg/1 or less
Salt, to 5 mg/1
TDS, to 20 mg/1
Total

Total

Total
                                   120

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                        WASTE TREATMENT SYSTEMS

The  waste  treatment systems included in this report as appropriate for
use on meat packing plant waste water streams can be used by all  plants
in  the  industry.  The treatment systems will work, subject to specific
operating  constraints  or  limitations.   However,  the  cost  of  such
treatment  systems may be uneconomical or beyond the economic capability
of some plants.

The waste  treatment  systems,  their  use,  and  the  minimum  effluent
reduction  associated  with  each are listed in Table 10.  The dissolved
air flotation system can be used upstream  of  any  secondary  treatment
system.    When   operated  without  chemicals,  the  by-product  grease
recovered in the floe skimmings  has  an  economic  value  estimated  at
112/kg   (52/lb).   The  use  of  chemicals will increase the quantity of
grease removed from the waste water stream, but may reduce the value  of
the grease because of the chemical contaminants.
Elementary biological treatment systems generally require more land than
Mechanically   assisted  systems  which  in  turn  increase  the  energy
consumption and cost of equipment  in  achieving  comparable  levels  of
waste reduction.  Some of the tertiary systems are interchangeable.  Any
of them can be used at the end of any of the secondary treatment systems
to  achieve  a required effluent quality.  Chlorination is included if a
disinfection treatment is required.  A final clarifier has been included
in  costing  out  all  tiological  treatment  systems  that  generate  a
substantial  sludge  volume;  e.  g,,  extended  aeration  and activated
sludge.  The clarifier is need to reduce the solids content of the final
effluent.

The most feasible system for no discharge at this time is flood or spray
irrigation, or, in some cases, evaporation from a shallow pond,  closing
the loop to a  total  water  recycle  or  reuse  system  is  technically
feasible, but costly.  The irrigation option does require large plots of
accessible  land—roughly  2.7 hectares/million liters (25 acres/million
gallons)  of waste water per day; and limited concentrations of dissolved
solids.  More detailed descriptions of each  treatment  system  and  its
effectiveness   are  presented  in  Section  Vll-Control  and  Treatment
Technology.

Of all the  plants  in  the  study  sample  that  reported  waste  water
treatment,  55  percent  indicated  discharging raw waste to a municipal
treatment system.  Thirty-eight plants reported some  on-site  secondary
treatment.  Of the 38 plants, 63 percent used the anaerobic plus aerobic
lagoons  system.   This  system was used to treat large and small waste-
water streams alike, varying from 76,000 liters per day  (0.2 MGD) to 4.8
million liters per day  (1.3 MGD).  The rest of  the  systems  listed  as
secondary  treatment  were  used  by  1, 2, or 3 plants each, except the
                                  121

-------
rotating biological contractor, which is now being  evaluated  at  full-
scale at one site.

Dissolved  air flotation is used as a primary treatment, either alone or
along with screens or a catch basin, by about 30 percent of  the  plants
in the sample.  About 5 percent use chemicals in the flotation system.

Chlorination  is a rare practice, according to the information collected
in the survey questionnaires; it appears to be used by about  5  percent
of the plants.

Other  than  sand filters and spray irrigation, there is no reported use
of any of the advanced treatment systems.  Sand  filters  are  used  for
secondary  treatment  in  Ohio  instead  of anaerobic lagoons, which are
discouraged by the Ohio Environmental  Protection  Administration.   The
few  spray  irrigation  systems  are  located  in  arid  regions  of the
Southwestern U.S.

Among the industry subcategories,  for  which  we  have  specific  plant
information,  slaughterhouses  have  almost  twice as many air flotation
systems in  use   as  do  packinghouses.   Municipal  treatment  and  the
anaerobic  plus   aerobic  system for secondary treatment are used by the
bulk of the industry,  A breakdown of the sample by  subcategory  is   as
follows:
                  Secondary Treatment by Each Subcategory, %

Municipal
treatment , %
Anaerobic +
aerobic
lagoons, %
Other, %
TOTAL
Simple
Slaughter-
house
56
33
11
100%
Complex
Slaughter-
house
29
65
6
100%
Low-
Processing
Packing-
house
70
11
19
100%
High-
Processing
Packing-
house
59
14
27
100%
North Star
Sample of
Industry
55
28
17
100%
 The  complex  slaughterhouses   have  an  unusually  low percentage using
 municipal treatment in comparison with the  other  three  subcategories.
 The   plants   in   this   subcategory  are  typically  the  large-scale
 slaughterhouses and they tend  to be located close to the  animal  supply
 rather  than in cities, thus often precluding municipal treatment.  This
 tabulation does not take into  account the large number of  small  plants
 in  the  industry.    Depending  on  the source of information, the total
                                   122

-------
number of plants in the industry  varies  from  4000  to  6000  and  the
approximate  percentage  of  small  plants varies from 85 to 90 percent.
However, these small plants account for only 10 percent or less  of  the
industry's  output  and,  probably, a somewhat smaller proportion of the
total waste water load.  Of the few small plants  for  which  data  were
available,  about  50 percent reported discharging waste water into city
sewers.  The remaining 50 percent  used  a  wide  variety  of  secondary
treatment  systems.   Based  on  all of the available information, it is
estimated that 50 percent of the small plants  use  municipal  treatment
facilities,  a  small percent probably dump raw waste into local streams
or use land disposal, and the remaining plants treat  their  own  waste.
Taken  as  single  point  sources  of  waste  water,  these small plants
represent an unknown but a very small fraction of the total wasteload on
receiving streams.
                                  123

-------
                          TREATMENT AND CONTROL COSTS

                              In-Plant^Cgntrol ..Cost s

The cost of  installation of  in-plant  controls is primarily a function of
the specific plant situation.   Building layout and   construction  design
will  largely  dictate  what  can be done, how, and at what  cost in regard
to  in-plant  waste  control techniques.   No  in-plant   control  costs   were
included  in the cost estimates for Level  1 and  2 technologies,  although
a dissolved  air flotation system  as primary treatment  was  included  in
the  Level   2 costs.  Rough  approximations of the range  of costs for the
in-plant controls  requiring  capital equipment are listed in Table 11.
                Table 11.   In-Plant  Control Equipment Cost Estimates
                Plant Area
                                 Item
                     Equipment Cost Range
                Pen wastes
                Blood handling
                Paunch handling
                Viscera handling

                Troughs

                Rendering



                Hide processing


                Hog Scald Tank
                Pickle & Curing
                solutions
                Water Conservation

                Water Conservation
Roof on pens

Manure sewer

Curbing & collection
  system

Blood dryer

Solids pumping
  system

Liquid screening &
  collection equip-
  ment

Localized catch basin
Surface condensers

Tankwater evaporator

Overflow collection
  & treatment

Water treatment &
reuse system

Solution collection,
treatment, reuse
system

Install spray nozzles

Press-to-open &
foot operated valves
$5000 - $10,000

$8 - $12/foot


$10,000 - $50,000

$30,000 - $50,000


$10,000 - $20,000


$5,000 - $10,000


$6,000 - $12,000

$5 - $10/foot

$15,000 - $20,000

$50,000 - $200,000


$5,000 - $20,000



 $10,000 - $25,000




 $10,000 - $30,000

 $5,000 - $10,000



 $10,000 - $20,000

-------
                 Secondary and Tertiary Treatment Costs

The total investment cost and annual cost  expressed  in  0/100  kg  LWK
(2/100  Ib LWK)  are reported by subcategory for each secondary treatment
system, air flotation, and chlorination in Table 12.   These  costs  are
listed  on the same basis for each tertiary or advanced treatment system
in Table 13.

The annual costs of secondary treatment for all categories vary from 6.0
to 17.8 0/100 kg LWK  (2.7 to 8.1 0/100 Ib LWK),  excluding  the  highest
figures.   The  10-year  (1962-1971)  average  earnings  reported by the
American  Meat  Institute  are  750/100  kd   (340/100  Ib)  LWK,   These
estimated  annual  costs of waste treatment, which are very conservative
from an accounting viewpoint, represent between 8 and 24 percent of  the
10-year average earnings,  Presuming an acceptable recycle water quality
can  be  achieved  throuuh  advanced  waste treatment, including ammonia
stripping, ion exchange, carbon adsorption, and chemical  precipitation,
the total estimated investment would vary from $700,000 to $1.6 million,
including  secondary treatment costs.  The annual costs would range from
26 to 550/100 kg LWK  (12 to 250/100 Ib LWK), or about 35 to  74  percent
of the lOyear average earnings.

No  discharge  could  be  achieved  by a spray irrigation system, incor-
porating partial treatment by ion exchange to reduce  dissolved  solids,
and would result in tctal costs between $270,000 and $544,000 and annual
costs between 13 and 240/100 kg LWK  (6 and 110/100 Ib LWK) .
The waste treatment system costs are based on the kill, waste water flow
and  BODjj  figures  listed previously for a "typical", but hypothetical,
plant  in  each  subcategory.   Investment  costs  for  specific   waste
treatment  systems  are largely dependent on the waste water flow.  Some
of the lagoon systems are designed on BOD5 loading, which has been shown
to increase with increased water use.

In averaging the waste water flow for each  subcategory,  it  was  found
that  one  standard deviation for three subcategories was 100 percent of
the average water flow, and 75 percent of  the  average  for  the  other
subcategory.    The   capacity-cost   relationships  of  the  biological
treatment systems tend to flatten out as the capacity  approaches  3.785
million  liters   (1 million gallons) per day.  Thus, the investment cost
of treatment facilities will not change substantially with small changes
in water use, and interpolation or extrapolation of investment cost  for
different  capacities  is best made by the use of graphical presentation
and analysis of the data.  However, the capacity-cost relationships of
                                  125

-------
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the advanced treatment systems are more similar to those  of  a  typical
process  industry,   with  a capacity ratio exponent between 0.6 and 0.8,
and cost estimates  may be made using the exponential approach.    Because
of  industry  variability  and  cost  estimating approximation, specific
plants within each  sutcategory will  incur  waste  treatment  investment
costs  which  will  differ from those reported for each subcategory by as
much as 50 to 100 percent, and perhaps more.

The investment cost data were collected from  the  literature,   personal
plant  visits,  equipment  manufacturers,  engineering  contractors, and
consultants.  These costs are "ball-park"  type  estimates  implying  an
accuracy  of  +  20  to  25 percent.  Rarely is it minus.  All costs are
reported in August 1971 dollars.  Percentage factors were added  to  the
basic  system  estimate  for  design  and engineering (10%) and for con-
tingencies and omissions  (15%).  Land costs were estimated to  be  $2470
per hectare ($1000  per acre) .

In  addition to the variation in plant water flows and BODS loadings and
the inherent  inaccuracy  in  cost  estimating,  one  additional  factor
further  limits  the probability of obtaining precise cost estimates for
waste treatment systems.  This  factor  was  reported  by  a  number  of
informed  sources  who  indicated  that municipal treatment systems will
cost up to 50 percent more  than  comparable  industrial  installations.
The  literature  usually  makes  no  distinction  between  municipal and
industrial installation in reporting investment costs,


                        Annual Costs Assumptions

The components of  annual  costs  include  capital  cost,  depreciation,
operating  and  maintenance costs, and energy and power costs.  The cost
of capital is estimated to be ten percent of the investment cost for the
meat packing industry.  This cost should be a weighted  average  of  the
cost  of  equity and of debt financing throughout the industry.  Neither
individual companies nor  industry associations have a known  figure  for
this  cost.   Presuming   that  target  and realized return-on-investment
 (ROI) or return-on-assets  (ROA) figures  incorporate  some  estimate  of
capital cost plus an acceptable profit or return, industry and corporate
reports  were  used  as a guide in selecting the 10 percent figure.  One
sample of companies reported earnings at 7.1 percent of total  assets for
1971, 35 a recent business periodical reported earnings at 10.1  percent
of  invested  capital,  36 and general industry sources report corporate
target ROI or ROA figures at 12 to 15 percent for new ventures.  The ten
percent figure is probably conservative and thus tends to  result   in   a
high estimate of annual cost.

The  depreciation  component of annual cost was estimated  on a straight^
line basis over the following lifetimes, with no salvage value:
                                   128

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    Land costs — not depreciated

    Cost of improvements for land intensive treatment — 25 years

    Simple treatment systems without complex process equipment:
    e.g., extended aeration, sand filter — 25 years

    Treatment systems requiring complex process equipment -- 10  years

The operating and maintenance costs include the cost of one man-year  at
$4.20/hr for each typical secondary treatment system plus 50 percent for
burden,  supervision,  etc.   One-half man-year was included in  the If a
licensed
         treatment plant operator is assumed, an additional annual cost
of $5000.  would be reflected in operating costs.  annual cost for  each
tertiary  treatment  plus  the  50  percent  burden,  etc.   General and
maintenance supplies,  taxes,  insurance,  and  miscellaneous  operating
costs  were estimated as 5 percent of the total investment cost  per year
for process equipment  based  systems  and  2.5  percent  of  the  total
investment  cost  for  land intensive waste treatment systems.  Specific
chemical-use costs were added when such materials were consumed   in  the
waste  treatment system.  By-product income, relative to waste treatment
was credited only in the dissolved air flotation system for 160  mg/1  of
grease  recovered  per  day  and  sold  at $0.05 per pound, and  in spray
irrigation for 13,400 kg of dry matter (hay or  grass)   per  hectare  at
$22/100 kg  (6 tons/acre at $20/ton)  and one crop per season.


                          ENERGY_REOJJIRJEMENTS

The  estimated  electrical  energy  consumption  per plant based on 1967
Census of Manufacturers 37 data is as follows:

         Small plants -- 0.72 million KWH per year

         Medium plants —r 5.5 million KWH per year

         Large plants -- 18.6 million KWH per year

The meat  packing  industry  consumes  relatively  small  quantities  of
energy.  The waste treatment systems require power primarily for pumping
and  aeration.   The  aeration horsepower is a function of the wasteload
and that for pumping depends on waste water flow rate.

Power consumption for waste treatment varies from 0.8 to 3.4 million KWH
per year for various secondary treatment systems.  This  consumption  is
between  10 and 40 percent of that indicated above for 1973.  The larger
plants with greater power consumption would tend toward the smaller per-
centage.  The total additional power consumption to achieve Level 1  and
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Level  2 does not appear to raise serious power supply or cost questions
for the meat packing industry.

Thermal  energy  costs  roughly  equal  electrical  energy   costs   for
operations  within  the  industry.    Waste  treatment  systems impose no
significant addition to  the  thermal  energy  requirements  of  plants.
Waste  Water  can  be  reused in cooling and condensing service if it is
separated from the process waters in surface condensers.    These  heated
wastewaters  improve the effectiveness of anaerobic ponds which are best
maintained  at  90°F  or  more.   Improved  thermal   efficiencies   are
coincidentally achieved within a plant with this technique.

Waste Water treatment costs and effectiveness can be improved by the use
of energy and power conservation practices and techniques in each plant.
The  wasteload  increases  with  increased water use.  Reduced water use
therefore reduced the wasteload, pumping costs, and heating  costs,  the
last  of  which  can  be  further  reduced  by  water reuse as suggested
previously.


             NON-WATER POLLUTION BY WASTE TREATMENT SYSTEMS

                              Solid Wastes

Solid wastes are the most significant  non-water  pollutants  associated
with  the  waste  treatment  systems  applicable  to  the  meat  packing
industry.  Screening devices of various design and operating  principles
are  used  primarily  for  removal  of  large-scale solids such as hair,
paunch manure, and hog stomach contents from waste water.  These  solids
may have some economic value as inedible rendering material, or they may
be landfilled or spread with other solid'wastes.

The solids material, separated from the waste water stream, that contain
organic  and  inorganic  matter,  including  those  added  to aid solids
separation, is called sludge.  Typically, it contains 95 to  98  percent
water  before  dewatering  or  drying.   Both  the primary and secondary
treatment systems generate some quantities of sludge; the quantity  will
vary by the type of system and is roughly estimated as follows:
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Treatment System
Dissolved air flotation

Anaerobic lagoon

Aerobic and aerated lagoons

Activated sludge

Extended aeration

Anaerobic contact process

Rotating biological ccntactor
Sludge Volume as Percent of raw
waste water volume
Up to 10%

Sludge accumulation in these
lagoons is usually not sufficient
to require removal at any time.

10 - 15%

 5 - 10%

approximately 2%

unknown
The  raw  sludge can be concentrated, digested, dewatered, dried, incin-
erated, land^filled or sub-surface injected on-site, or spread in sludge
holding ponds.  The sludge from any of the treatment systems, except air
flotation with polyelectrolyte chemicals added, is amenable  to  any  of
these sludge handling processes.

The  sludge  from  air  flotation with chemicals has proven difficult to
dewater.  A dewatered  sludge  is  an  acceptable  land  fill  material.
Sludge  from  secondary treatment systems is normally ponded by the meat
industry plants on their own land or dewatered or digested  sufficiently
for  hauling  and  deposit in public land fills.  The final dried sludge
material can be safely used as an effective soil builder.  Prevention of
run-off is a critical factor in plant-site sludge holding ponds.   Costs
of  typical  sludge  handling  techniques  for  each secondary treatment
system generating sufficient quantities of sludge  to  require  handling
equipment are already included in the costs for these systems,


                             Air^Pollutign

Odors  are  the  only  significant air pollution problem associated with
waste treatment in the meat  packing  industry.   Malodorous  conditions
usually  occur  in  anaerobic  waste  treatment  processes  or localized
anaerobic environments within aerobic systems.  However, it is generally
agreed that anaerobic pcnds will not create serious odor problems unless
the process water has a high sulfate content;  then  it  most  assuredly
will.   Sulfate waters are definitely a localized condition varying even
from well to well  within  a  specific  plant.   In  northern  climates,
however,  the  change  in  weather in the spring may be accompanied by  a
period of increased odor problems.
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The anaerobic pond odor potential is somewhat unpredictable as evidenced
by a few plants that have odor  problems  without  sulfate  waters.   In
these  cases a cover and collector of the off-»gas from the pond controls
odor.  The off-gas is then burned in a flare.

The other potential odor generators in the waste treatment are tanks and
process equipment items for the anaerobic contact process that  normally
generate  methane.   However,  with  the  process confined to a specific
piece of equipment it is relatively easy to confine and control odors by
collecting and burning the off-gases.  The high heating value  of  these
gases  makes it worthwhile and standard practice to recover the heat for
use in the waste treatment process.

Odors have been generated  by  some  air  flotation  systems  which  are
normally  housed  in  a  building, thus localizing, but intensifying the
problem.  Minimizing the unnecessary holdup of any skimmings or  grease-
containing solids has been suggested as a remedy.

Odors  can  best  be  controlled by elimination, at the source, in pref-
erence to treatment for odor control which remains largely  unproven  at
this time.


                                  Noise

The  only  material  increase  in noise within a packing plant caused by
waste treatment is that caused by the installation of an  air  flotation
system  or  aerated  lagoons  with  air blowers.  Large pumps and an air
compresser are part of an air flotation system.  The  industry  normally
houses such a system in a low-cost building; thus, the substantial noise
generated  by  an air flotation system is confined and perhaps amplified
by the installation practices.  All air compressors,  air  blowers,  and
large  pumps  in use on intensively aerated  treatment systems, and other
treatment systems as well, may produce noise levels  in  excess  of  the
Occupational  Safety  and Health Administration  standards.  The industry
must consider these standards in solving its waste pollution problems.
                                   132

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                               SECTION IX

               EFFLUENT REDUCTION ATTAINABLE THROUGH THE
              APPLICATION OF THE BEST PRACTICABLE CONTROL
                     TECHNOLOGY CURRENTLY AVAILABLE
                    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 appli-
cation of the Best Practicable Control Technology  Currently  Available.
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  a  broad  range  of
plants  within  the  ireat  packing  industry, but based upon performance
levels achieved by exemplary plants.

Consideration must also be given to:

    o    The total cost of application of technology in relation to
         the effluent reduction benefits to be achieved from such
         application;

    o    The size and age of equipment and facilities involved;

    o    The processes employed;

    o    The engineering aspects of the application of various types
         of control techniques;

    o    Process changes;

    o    Non-water 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
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the  engineering  and  economic  practicability of the technology at the
time of start of construction of installation of the control facilities.
       EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
       BEST PRACTICAEIE CONTROL TECHNOLOGY CURRENTLY AVAILABLE

Based on the information contained in Sections III through VIII of  this
report,  a  determination  has  been  made  that the quality of effluent
attainable  through  the  application  of  the  Best  Pollution  Control
Technology  Currently Available is as listed in Table  1U.  A  number of
plants in the industry which have biological treatment systems for which
effluent quality data were available are meeting these standards.

Exceptional cases may arise occasionally that  require  adjustment.   An.
example  is a plant that processes a large volume of hides or blood from
other plants in addition to its own.  Adjustments can  be  made  to  the
effluent  guidelines  on  the basis of information contained in Sections
IV, V, and VII  for  BOD5r  suspended  solids,  Kjeldahl  nitrogen,  and
ammonia.   The adjustments for exceptions are listed in Table 15.  It is
assumed that the grease,  phosphorus,  and  nitrite-nitrate  levels  are
unaffected.

              IDENTIFICATION OF BEST PRACTICABLE CONTROL
                    TECHNOLOGY CURRENTLY AVAILABLE

Best  Pollution  Control  Technology  Currently  Available  for the meat
packing industry involves biological waste treatment following  in^plant
solids  and  grease  recovery  steps.   To  assure  that  treatment will
successfully achieve the limits specified,  certain  in-plant  practices
should be followed.
    1,   Reduce water use by shutting off water when not  in use,
         practicing extensive dry clean-up before washing, and
         exercising strict management control over housekeeping and
         water use practices,  Water use should be controlled at
         least to the following values:

   Class of Plant                 liters/1000 kg LWK      gal/1000  Ib LWK
    Simple slaughterhouse               5,416               650
    Complex slaughterhouse              7,U97               900
    Low-processing packinghouse         8,333              1000
    High-processing packinghouse*      12,U95              1500

*This  is for an assumed mix of kill and processing of about 0,65 kg
processed meat products/kg LWK.
                                   13<4

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            Table 14.   Recommended Effluent Limitations for  1 July 1977

Plant
Subcategorv (1)

S imple
Slaughterhouse
Complex
S laughter house
Low- Process ing
Packinghouse
High-Processing
Packinghouset
BOD
kg/ 1000 kg
LWK

0.08
0.17
0.12
0.24
Suspended
Solids
kg/ 1000 kg
LWK

0.18
0.22
0.20
0.31
Grease
mg/1

10
10
10
10
 tlhe values  for  BODs  and  suspended  solids  are  for  average  plants; 'i.e., plants
  with a ratio  of average  weight  of  processed meat  products to  average LWK of
  0.55.   Adjustments can be made  for high-processing  packinghouses at other
  ratios according to  the  following  equations:
       kg BOD5/1000 kg LWK = 0.21 + 0.23 (y - 0.4)

       kg SS/1000 kg LWK = 0.28 + 0.30 (y - 0.4)
          where  y  = kg  processed meat products/kg LWK.
(l)For all subcategories pH should range between  6.0  and  9.0  and  fecal  coliform
   bacteria  should  be controlled to 400  counts/100 ml at  any  time.
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              Table 15.   Adjustment Factors for Exceptions in
                         Plant Subcategories—1977
Exceptional Practice
Processing hides from other
plants in addition to own:
Defleshing, washing,
cur ing
Processing blood from other
plants in addition to own:
Steam coagulation and
s cr e en ing , s ewer ing
water
Rendering material from
other plants in addition
to own:
Wet and low-temperature,
sewering water
Dry
Adjustment Factors j
BOD5
0.02
0.02
0.03
0.01
Suspended
Solids
0.04
0.04
0.06
0.02
Incremental                               ,
Adjustment     = (Adjustment   (Total weight of source animals* in 1000's kg)
to Guidelines,     Factor)   X           (Plant LWK in 1000's kg)
*Source animals are those animals killed at another location from which the
 additional hides, blood, etc., originate.  If the source animal weight is
 unknown it can be estimated by the use of the following:
     For blood:
     Source animal weight
     in 1000's kg
                       (liters of blood) x (0.028) or (gal of blood) x (0.108)
= (kg °f
                                       (0'029)  °r
                                                           °f blood) x (0'013)
     For rendering material:
     Source animal weight _ (kg of rendering materials) x (0.0067) or
     in 1000' s kg           (Ib of rendering materials) x (0.003)
For cattle hides;

Source animal weight
in 1000' s kg
                                     , , . .  .    .„ . ,_.
                                    °f hldes)  X (0'A5)
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The above values of water use represent the averages for the
subcategories.  They vary because of differences in water
requirements and, to a 1- sser extent, practices for subcategories.
The 1977 effluent guidelines were based on these water flows.
It is possible for each ..ubcategory to achieve its flow rate
without large in-plant modifications; however, many plants
will require greatly improved water control and housekeeping practices.

    2.   In-plant recovery systems should include, as a minimum, a
         gravity catch t-isin with at least a 30-minute detention time;
         further additic;: of air flotation is more effective.

    3.   Blood recovery  hould be practiced extensively, with all
         major bleeding . reas curbed and with separate drains to
         blood collectic.  tanks.  If blood is coagulated, blood
         water should be evaporated.
    4.   Water from lew iemperature rendering should be evaporated.
    5.   Barometric leg *vaporators which tend to foam, such as for
         tankwater evaporation, should be equipped with foam breakers
         and demisters.

    6.   Uncontaminated  ooling water should not be discharged to
         the secondary w iste treatment system.
    7.   Paunch contents should be dumped without using water.

The above in-plant practices, in addition to good housekeeping, can
readily produce a raw wa::te load below that cited as average in section V.
With an average waste lc;d, the following secondary treatment systems
are able to meet the stated guidelines:

    1.   Anaerobic lagoon + aerated + aerobic  (shallow) lagoon
    2.   Anaerobic lagocn + extended aeration
    3.   Anaerobic -centart process + aerobic  (shallow) lagoons
    4.   A solids removal, stage and chlorination may be required as
         a final process.


                     RAT = ONALE FOR THE SELECTION OF
        BEST^PRACTICAEIE' CONTROL,TECHNOLOGY CURRENTLY^AVAILAELE

Age_and^Size of Equipmert^and_Facilities

The industry has generally modernized its plants as new methods that are
economically  attractive  have been introduced.  No relationship between
age of production plant ind effectiveness of  its pollution  control  was
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found.   Also, size is not a significant factor,  even though plants vary
widely in size.  Small plants are not mechanized to the  extent  of  the
rest  of  the  industry;  still  they  are  able  to achieve at least as
effective control as larger plants.   This is partly because  the  small-
scale  of  operation permits options for simple paunch viscera and blood
disposal, with small low-cost in-»plant equipment that are  not  open  to
large operations because of the immense volume of materials concerned.


Total^CQStTgf,Applicatignvin^gl§tion to Effluent^Reduction^Benefitg

Based  on  the information contained in Section VIII of this report, the
industry as a whole would have to invest an estimated amount of b  $52.8
million  to achieve the effluent limitations described.  This amounts to
a cost of about $2,355 for installed capacity  of  one  million  kg  LWK
 ($1,069  per one million Ib) per year.  The cost increase will amount to
about $0.345/1000 kg LWK  ($0.157/1000 Ib LWK).  Based  on  an  estimated
overall  investment  of $1.7 billion, the maximum increase in investment
would be about 3 percent.  This also represents about 20 percent of  the
capital expenditures reported for 1971. 3S

All  plants  discharging  to  streams  can  implement the Best Pollution
Control Technology Currently Available.  The technology is not  affected
by different processes used in the plants.


Engineering Aspects, of control T^chnigue^Applications

The  specified  level  of  technology is practicable because it is being
practiced by plants representing a wide range of plant sizes and  types.
The  parameters  pH and fecal coliform are limited for all subcategories
as discussed under "Simple Slaughterhouses.11


Simple_Slaughterhouses

The BODS guideline was taken as the average of five plants in  the   sub-
category.   The  average  was  0.076  kilograms  per 1000 kilograms  live
weight killed  (kg/kkg LWK).  A sixth plant that was very unusual in   its
operation  came  in the same range, but was not included in the average.
A seventh plant  (but one  that discharged to a municipal system)  had an
extremely  low  raw  waste  load  and, with the less than an outstanding
biological treatment, would have readily met the  requirement.   Of   the
five  plants used for the average, three had final BODS values less  than
the standard.

The suspended  solids content varied much  more  widely  among  the   five
 plants   above,  with  an  average of  0.18 kg/1000 kg LWK.  Of these  five
plants,  two were particularly high in suspended solids—between 0.3   and
                                   138

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0.4  A  suspended  solids  level  that  is higher than the BODS level is
normally encountered for biological treatment systems particularly those
which are highly efficient in BOD reduction.  As a further check on  the
vercity  of  this  number  it was determined that three of the exemplary
biological treatment  systems  averaged  about  97  percent  removal  of
suspended solids.  When this factor was applied to the average suspended
solids  of the raw waste load for the subcategory of 5.6 kg/1000 kg LWK,
the result was 0.17 kg/1000 kg Iwk.  Plant operation with a lower  than-
average  raw waste load and with a similar treatment system would give a
suspended solids value well within the guideline.

The average grease content in the treated effluent from the five  plants
was below the range of the reliability of the analytical method used for
grease   (10  mg/1) .   This limit would give a grease value of about 0.03
kg/1000 kg LWK.  From  the  removal  efficiency  standpoint,  98  to  99
percent  was  achieved  in  the better plants.  These efficiencies would
reduce the grease in the average raw waste to the limit specified.

Control of pH in the range of 6.0 to 9.0 is as commonly  encountered  in
raw waste and treated effluents; control of fecal coliform to 400 counts
per 100 mg/1 is readily accomplished by chlorination.
Com£lex_ Slaughterhouses

BODS  limitations for complex slaughterhouses are based upon averages of
actual effluent data for four  plants  in  the  subcategory.   Suspended
solids  proved quite variable for plants in this subcategory; in several
instances raw wastes at the same or  lower  suspended  solids  level  as
simple  slaughterhouses were not as effectively removed.  The limitation
is at a level achieved by one plant in  this  subcategory,  five  plants
with  similar  raw  wastes in the simple slaughterhouse subcategory, and
within 25-30 percent of the suspended solids for two other plants in the
subcategory.  The limit is approximately 30  mg/1  in  concentration  as
further  verified  by using the average raw waste load for the 13 better
plants and the recommended flowrate of 900 gal/1000 Ib Iwk.

The grease level was determined from the  average  of  the  five  grease
values  reported  by the best 13 complex slaughterhouses mentioned above
for which the average raw waste load was  2.7  kg  grease/1000  kg  LWK.
Although there were no exemplary treatment systems for this subcategory,
North  Star field tests showed one plant to be below the analytical test
limit for grease, while questionnaire data showed that another plant was
just slightly over this amount.
                                   139

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Low-Processing Packinghouses

As outlined in Section V, BOD and suspended solids vary  primarily  with
kill  rather  than  processing rate.   As a consequence, limits for these
parameters in this sutcategory may be  partically  verified  by  knowing
kill  rates  in  low  processing  packinghouses  and  simple and complex
slaughterhouses.  Since kill rates for this subcategory  typically  fall
between  those  for  the  slaughterhouse  subcategories,  raw  waste and
effluent BOD and suspended solids would show the same  relationships  if
the same treatment technology were applied.  Available data revealed the
relationship  to  be  expected  even  though  treatment systems for this
subcategory showed rather poor performance.  However, one plant  already
meets  the  limits  for  both  parameters and the addition of mechanical
aeration and measures to reduce raw waste  loads  would  readily  permit
four  more plants to meet the limits.  No correction was applied for the
amount of processing in this subcategory because the ratio of  processed
products to LWK was so low that any adjustment was not significant.  The
value  obtained  for  grease corresponded to a concentration of 4.5 mg/1
for a plant with average flow (7842 1/1000 kg LWK).  Again this is below
the reliable limit of the method analysis, which is 10 mg/1;  hence,  10
mg/1 was chosen as the limit.
High-Processing Packinghouse.s
—*_      r^r* L^_ i_--rt-i ••—^-*j-_i_  ^ ^LJ^^M^T^

The  BOD5  and suspended solids effluent limits were derived by applying
the exemplary treatment technology proven in use by plants in the  other
three subcategories to the average raw waste values given in Table 5 for
this  subcategory.   This  resulted  in effluent limit values of 0.24 kg
BOD5/1000 LWK and 0.31 kg suspended solids/1000  kg  LWK;  these  values
apply   to  a  high-processing  packinghouse  that has a ratio of average
weight  of processed products to average LWK of 0.55.   However,  because
the amount of processed products relative to the LWK varies considerably
for  highprocessing  packinghouses,  adjustments  for BOD5 and suspended
solids  were developed for plants having a ratio  of  average  weight  of
processed  products  to  average LWK other than 0.55.  These adjustments
are presented at the bottom of Table 14.  The adjustment equations  were
derived from  two equations for predicting the total BODS and suspended
solids  in the  raw  effluent  from  the  LWK  and  amount  of  processed
products,  and  by  assuming  exemplary  treatment removals for BOD5 and
suspended  solids  of  98.5  and  97  percent,  respectively.   The  two
predicting  equations were developed from a multiple regression analysis
of the  combined  raw  waste  data  for  both  low-  and  highprocessing
packinghouses.

The  use  of the same proven technology regarding grease showed that for
the raw wastes from eight plants in the subcategory, the final  effluent
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would  contain  no  more  than  the  specified  limit  at  the  level of
reliability for the analytical method for the grease determination.
Process Changes

Significant in-plant changes will not be needed by the vast majority  of
plants  to  meet the limits specified.  Many plants will need to improve
their water conservation practices and housekeeping, both responsive  to
good  plant  management  control.  Some plants may find that addition of
improved gravity separation systems, such as air flotation with chemical
precipitation, may enable them to meet the guidelines more readily.


Non-Water Quality^Environmental Impact

The major impact when the option of an activated sludge-type of  process
is  used  to  achieve the limits will be the problem of sludge disposal.
Nearby land for sludge disposal may be necessary^—in some cases a sludge
digester  (stabilizer) may offer a solution.  Properly operated activated
sludge-type systems should permit well conditioned sludge to  be  placed
in small nearby soil flcts for drying without great difficulty.

Another  problem  is  the  odor  that  emits periodically from anaerobic
lagoons.  Covering with a plastic sheet and burning the off-gas offers a
potential solution to this problem.  It  is  necessary  to  avoid  high-
sulfate  water  supplies.   The  odor  problem  can  be avoided with all
aerobic systems.

It is concluded that no new kinds  of  impacts  will  be  introduced  by
application of the best current technology.

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                               SECTION X

       EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
        THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE —
                    EFFLUENT LIMITATIONS GUIDELINES

                              INTRODUCTION

The  effluent  limitations  which must be achieved no later than July 1,
1983, are not based on an average of  the  best  performance  within  an
industrial  category,  but  are  determined by identifying the very best
control and treatment technology employed by  a  specific  point  source
within  the industrial category or subcategory, or by one industry where
it is readily transferable to another.  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.

Consideration must also be given to:

    o    The age of the equipment and facilities involved;

    o    The process employed;

    o    The engineering aspects of the application of various types
         of control techniques;

    o    Process changes;

    o    The cost of achieving the effluent reduction resulting
         from application of the technology;

    o    Non-water quality environmental impact  (including energy
         requirements).

Also,  Best  Available Technology Economically Achievable emphasizes in-
process controls as well as control or additional  treatment  techniques
employed at the end of the production process.

This  level  of  technology  considers those plant processes and control
technologies which, at the pilot plant, semi-works,  and  other  levels,
have demonstrated both, technological performances and economic viability
at   a   level  sufficient  to  reasonably  justify  investing  in  such
facilities.  It is the highest degree of  control  technology  that  has
been  achieved  or has been demonstrated to be capable of being designed
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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 are intended to be  the
top-of-the-line of current technology, subject to limitations imposed by
economic and engineering feasibility.


          EFFLUENT REDUCTION ATTAINABLE^THROUGH APPLICATION OF
         THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVAlLE

Based  on  the information contained in Sections III through VII of this
report, a determination has been  made  that  the  quality  of  effluent
attainable  through  the  application  of  the Best Available Technology
Economically Achievable is as listed in Table  16,   The  technology  to
achieve  these  goals  is  generally available, although it may not have
been applied as yet to a packing plant or on a full scale.

Exceptional cases may arise occasionally that require adjustment in  the
guidelines--these   include   the  processing  of  large  quantities  of
materials (e.g., hides and blood) from other plants in addition to their
own.  Adjustments can be made on the basis of the information  contained
in  Sections  IV,  V,  and  VII  for  BODS  and  suspended  solids.  The
adjustments for exceptions are listed in Table 17.   Kjeldahl  nitrogen,
ammonia,  phosphorus, and nitrite-nitrate levels which are concentration
limited are unaffected.

It should also be  pointed  out  that  a  packer  should  consider  land
disposal,  and  hence  no  discharge,  for 1983.  Where suitable land is
available, evaporation or irrigation is  an  option  that  net  only  is
recommended  from the discharge viewpoint, but also will usually be more
economical than the system otherwise required.


            IDENTIFICATION OF^THE BEST AVAILABLE^TECHNOLOGY
                       ^ECONOMICALLY ACHIEVABLE

The Best Available  Technology  Economically  Achievable  includes  that
listed   under   the   Best  Practicable  Control  Technology  Currently
Available.  In addition, it  includes  improved  pretreatment,  such  as
dissolved  air  flotation  with pH control and chemical flocculation; an
ammonia  control  step  which  may   involve  ammonia  stripping   or    a
nitrification-denitrification  sequence; and a sand filter or equivalent
following secondary treatment.
                                  144

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                  Table 17.   Adjustments for Exceptions in All
                             Plant Subcategories—1983 in kg/kkg LWK
             Exceptional Practice
             Processing blood from other
             plants in addition to own:
                Steam coagulation and
                s cr eening,  sewer ing
                water

             Rendering material from
             other plants in addition
             to own:
                Wet and low-temperature,
                sewering water

                Dry
                                              Adjustment Factors
                           BOD5
                           0.007
                           0.01

                           0.003
                Suspended
                 Solids
                  0.013
                  0.02'

                  0.007
Incremental
Adjustment    = (Adjustment   (Total weight of source animals* in 1000's kg)
to Guideline,     _  .   -,    x •*	°——•	•	e"-
kg/1000 kg
Factor)
(Plant LWK in 1000's kg)
*Source animals are those animals killed at another location from which the
 additional hides, blood, etc., originate.  If the source animal weight is
 unknown it can be estimated by the use of the following:
   For blood;
   Source animal weight
   in 1000's kg'
   Source animal weight _
   in 1000's kg
   For rendering material;
        (liters of blood) x (0.028) or (gal of blood) x 0.108)
        (kg of blood) x (0.029) or (Ib of blood) x (0.013)
   Source animal weight _ (kg of rendering materials) x (0.0067) or
   in 1000's kg           (Ib of rendering materials) x (0.003)

   For hides;

   Source animal weight = (number of hides) x (0.45)
   in 1000's kg
                                 146

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In-plant controls and modifications are also required to achieve
the specified levels.  These include:

    o    Segregation of grease-bearing from nongrease-bearing waste
         streams;

    o    Water control systems and procedures to reduce water use
         to about 50 percent of that listed in Section IX;

    o    Processing or outside disposal of entire wet pauch contents
         or rendering of unopened paunch.

    o    Installation of surface (or comparable)  systems for
         heat exchangers and evaporators;
         Segregation, clean-up, and reuse of pickling and urine solutions

    o    Provision for collection of excess solutions;

    o    Installation of dry rendering operations;

    o    General elimination of viscera washing operations;

    o    Design for extensive use of troughs under carcass conveying
         lines;

    o    Instigation and continuous enforcement of meticulous dry
         clean-up and materials recovery procedures.
    o    Elimination of steam coagulation of blood and installation
         of whole blood drying equipment.

To reduce the water use to  the  required  levels,  several  changes  in
normal plant operations may be required.  Push-to-open valves need to be
used wherever possible.  Spray nozzles can be redesigned for lower water
flow.   Automatic  valves that close when the water is not in use should
be  installed;  examples  are  in  carcass  washers  and  for   washdown
operations.   Automatic  level  control  should  be used in pen watering
troughs.  Pens should be covered  in  areas  where  rain  and  snow  are
significant;  wood  chips  should  be  used for bedding and dry clean-up
procedures should be used.

Water reuse should be practiced, reusing water for lower quality  needs.
For  example,  carcass washing water can be reused for hog dehairing and
lagoon water can be reused for  cooling  waters   (this  latter  has  the
advantage of heating a lagoon for greater biological activity).

Dissolved  solids  can,  be minimized by changing some current practices.
Excess cure solutions should  be  collected  immediately  for  reuse  or
treatment.   Concentrated  brine  overflow  from  hide  curing should be
segregated for salt recovery, perhaps by evaporation.  Salt  should  not
                                  1U7

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be  used  on floors as an antislip material;  other methods are available
to counteract this problem.  Reducing carcass  and  head  washing  water
will  reduce  the body fluids (and thus the salts)  washed into the sewer
in this step.

If suitable land is available, land disposal is the best technology;  it
is  no  discharge.   Cepending on the amount and type of land, the above
in-plant techniques  and  primary  treatment,  including  dissolved  air
flotation  with  pH  control,  may be adequate before discharging to the
land.  On the other hand, a secondary treatment system may  be  required
before disposal to soil.  Any of the systems mentioned in Section IX, or
even  simpler  ones,  are  suitable.  The potential problem of dissolved
solids in irrigation  systems  can  usually  be  avoided  by  minimizing
dissolved  solids as described above; in some cases a part of the stream
may need to be treated by ion exchange.

Technology is available for  small  plants  for  no  discharge  via  the
irrigation  or  evaporation  or other land disposal methods.  Interim or
remedial concepts  include  irrigation  or  evaporation  or  other  land
disposal  methods.   Interim  or remedial concepts include a septic tank
used with a drainfield or large cesspool.  Strict in-plant controls  are
readily managed to minimize the raw waste load.

                     RATIONALE FOR.SELECTION OF THE
                BEST AVAILABLE TECHNoEpGY^ECONOMICALLY ACHIEVABLE

                Age and_ Size of Equipment and Facilities

Neither  size  nor  age  are found to affect the effectiveness of endof-
process pollution control.  Although in-plant  control  can  be  managed
quite effectively in older plants, some of the technologies required for
reducing  the  raw  waste  loads to the low levels that are possible are
costly to install in older plants.  For example, rerouting of sewers  to
segregate waste streams is both very difficult and costly.

Small plants, for the reasons discussed in Section IX, have more options
for  waste   control  than  do large plants.  It is anticipated that most
small plants will find land disposal the best choice.


                Total Cost of Application in Relatjon_to
                      Effluent_ ReductiorTjienef: its  ""*   ~*

Based on information contained in  Section  VIII  of  this  report,  the
industry as  a whole would  have to  invest up  to a maximum  of $107 million
above  that  required to meet the 1977  standards.  This amounts to a  cost
of about $U760 for installed capacity  of one million  kg LWK   ($2160  for
one  million pounds) per  year.  The operating cost increase will amount
to about $2.10/1000 kg LWK  ($0.96/1000 Ib LWK).  The  capital  investment
                                   148

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above  that  to  meet the 1977 standards amounts to about six percent of
the total investment of the industry, estimated at about  $1.7  billion.
It  also  equals about 44 percent of the capital investment reported for
the industry for 1971.

All plants discharging to  streams  can  implement  the  Best  Available
Technology  Economically  Achievable;  the technology is not affected by
different processes used in the plants.


          Engineering Aspects of^Control Technique Application

The specified level of technology is achievable.  It  is  already  being
met  for  BODS  and suspended solids by one plant, both medium and large
plants are included.   The  limits  are  not  being  met,  however,  for
ammonia,  Kjeldahl nitrogen, or phosphorus; newer technology is required
for these parameters.  Phosphorus is  effectively  removed  by  chemical
treatment in air flotation, and by filtration of the final effluent from
the  secondary  treatment.   The  greatest unknown is the nitrification-
denitrification step.  However, nitrification has been achieved in pilot
units andon tolimited extent in plant operations.   Denitrification  has
been  explored  successfully  on  laboratory  and pilot scales.  Ammonia
stripping may require pH adjustment and later neutralization;  it  is  a
technology transferred from other industries.

Each   of  the  identified  technologies,  except  ammonia  removal,  is
currently being practiced in one or more packing plants.  They  need  to
be combined, however, to achieve the limits specified.

Technology  for  land disposal is being used by several plants in Texas;
it is already being planned for at  least  one  plant  in  Iowa.   Other
industries,   e.g.,   potato   processing,  are  using  it  extensively.
Secondary treatment and large holding ponds may be required in the North
to permit land disposal over only about one-half the year.   Application
of  technology  for  greatly  reduced  water  use  will  facilitate land
disposal.


                            Process^Changes

In-plant changes will be needed  by  most  plants  to  meet  the  limits
specified.   These  were  outlined  in  the  "Identification of the Best
Available Technology Economically Achievable", above.
                                  149

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                        Non~Water Quality Impact

The major impact will occur when the land  disposal  option  is  chosen.
There  is  a  potential,  but  unknown,  long-term effect on the soil of
irrigation  of  packing  plant  wastes.   To  date,  impacts  have  been
generally obviated by careful water application management.

Otherwise,  the  effects  will essentially be those described in Section
IX, where it was  concluded  that  no  new  kinds  of  impacts  will  be
introduced.
                                   150

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                               SECTION XI

                   NEW SOURCE PERFORMANCE STANDARDS


                              INTRODUCTION

The effluent limitations that must be achieved by new sources are termed
performance  standards.   The  New Source Performance Standards apply to
any source for which construction starts after the  publication  of  the
proposed regulations for the Standards.  The Standards are determined by
addinq  to  the  consideration underlying the identification of the Rest
Practicable Control Technology Currently Available, 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. New Source Performance Standards are based on an analysis of
how  the  level  of  effluent  may be reduced by changing the production
process itself.   Alternative  processes,  operating  methods  or  other
alternatives are considered.  However, the end result of the analysis is
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
made  is  whether  a  standard  permitting no discharge of pollutants is
practicable.


Consideration must also be given to:

    o    Operating methods;

    o    Batch, as opposed to continuous, operations;

    o    Use of alternative raw materials and mixes of raw materials;

    o    Use of dry rather than wet processes (including substitution
         of recoverable solvents for water);

    o    Recovery of pollutants as by-products
                                  151

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              EFFLUENT REDUCTION ATTAINABLE FOR  NEW SOURCES

The effluent limitation for new sources is the  same as that for the  Best
Practicable Control Technology Currently Available  for   the  pollutants
BOD,   suspended  solids, ammonia, grease and total kjeldahl nitrogen.  In
addition to these pollutant parameters the following  additional   limits
on nutrients are required  for new sources.   (See Section  IX):

                                                Nitrite-
                                Phosphorus     Nitrate  Ammonia
                                   as  P           as N
                                                       **
       Plant                    kg/1000  kg       mg/1  kg/kkg LWK
   Subcategory                   LWK

   Simple Slaughterhouse        0.03           5.0     0.17

   Complex Slaughterhouse       0.07           5.0     0.2U

   Low-Processing
   Packinghouse                  0.07           5.0     0.2U

   High-Processing t             0.11           5.0     0.40
   Packinghouse


This  limitation  is readily achievable in newly  constructed plants.
However, the guidelines for the Best  Available  Technology Economically
Achievable should be kept  in mind;  it may be  a  practical  approach to
design a plant which approaches the 1983 guidelines.  Consideration should
also  be given to land disposal, which would be  no discharge; in many
cases this will  be the most attractive and economical option.
  **For treatment of these components, concentration becomes limiting at these levels.
   tThe values for BOD5 and suspended solids are for average plants; i.e., plants with a ratio of average
   weight of processed meat products to average LWK of 0.55. Adjustments can be made for high-processing
   packinghouses at other ratios according to the following equations:

        kg BODs/1000 kg LWK = 0.07 + 0.08 (y - 0.4)

        kg SS/1000 kg LWK - 0.09 + 0.10  (Y - 0.4)
          where y = kg processed meat products/kg LWK.

  (l)For all subcategories pH should range between 6.0 and 9.0 and fecal coliform bacteria
    should be controlled to 400 counts/100 ml at any time.
                                      152

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            IDENTIFICATION OF NEW SOURCE CONTROL TECHNOLOGY

The  technology  is  the same as that identified as the Best Practicable
Control Technology  Currently  Available  (see  Section  IX).   However,
certain  steps that will be necessary to meet the 1983 guidelines should
be considered and, where possible, incorporated.  These include:
o   In-Plant controls

         Segregation of grease-bearing streams  from nongrease-
         bearing waste streams;

         Water control systems and procedures to reduce water
         use considerably below those cited in  Section IX;

    -    Processing or cutside disposal of wet  paunch contents
         or rendering of unopened paunch.

    -    Installation of shell-in-tube or comparable systems for
         heat exchangers and evaporators;

    -    Provision for collection of excess cure solutions;

         Installation of dry rendering operations;

         General elimination of viscera washing operations;

    -    Design for extensive use of troughs under carcass conveying
         lines;

         Installation of dissolved air flotation, with provision
         for a second unit to be added later;

         Instigation and continuous enforcement of meticulous
         dry clean-up and materials recovery procedures.

o   End-of-Process Treatment

    -    Chemical and biological measures for nutrient
         removal, e.g. alum precipitation, nitrification-'
         denitrification;
    -    Land disposal  (evaporation, irrigation) wherever possible;
         this should be a prime consideration;

         Sand filter or microscreen for effluent secondary treatment;

         Solid waste drying, composting, upgrading of protein content.


         Sludge recycle and/or digestion
                                  153

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   RATIONALE FOR SELECTION OF BEST AVAILABLE DEMONSTRATED TECHNOLOGY

In addition to the discussion in Section IX on the  rationale  for  Best
Practicable  Control Technology Currently Available, additional comments
are  presented  regarding  technology  for  the  added  limitations  for
nutrients.

Chemical  precipitation for removal of phosphorus and residual suspended
solids is an accepted practice as  a  "polishing"  step  for  biological
treated  effluents  particularly  municipal wastes which contain similar
concentrations  of  phosphorus  as  biologically  treated  meat  packing
wastes.   Moreover,  the  general  concept of precipition for phosphorus
removal is now serving as the basis guidelines utilized in the State  of
North Carolina.

The  nitrite^nitrate limits are already being achieved by nine plants in
the State of Iowa  (of  which  two  plants  simultaneously  meet  ammonia
requirements).   High rate mechanical aeration to volatilize ammonia and
convert ammonia to nitrates is an accepted concept, as is  reduction  of
nitrates by anaerobic filters or similar denitrification systems.


With  further  regard  to  ammonia  control  as  part  of total nitrogen
removal, six plants within all subcategories already meet the  specified
limits  using  well  operated treatment systems.  The ammonia removal is
perhaps incidental to the efficient BOD and suspended solids controls at
these plants  and  is  not  directly  attributable  to  specific  design
requirements.   However,  new  sources  may  be  availed  of most recent
advances in  systems  for  denitrifying  effluents  using  extended  air
activated  sludge,  nitrification-denitrification-nitrogen  gas removal,
final clarification, and  chlorination  with  expected  high  levels  of
nitrogen  control  as  outlined  in  the EPA Technology Transfer Manual,
"Nitrification-Denitrification Facilities, August,  1973".
                                  154

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                              SECTION XII

                            ACKNOWLEDGMENTS


The assistance of the North Star  Research  and  Development  Institute,
Minneapolis,  Minnesota  is  gratefully  appreciated.  Their program was
directed by Dr. E.E. Erickson; Project Engineers  were  Messrs  John  P.
Pilney  and  Robert  J.  Reid.  Special assistance was provided by North
Star staff members: Mrs. Janet McMenamin, Messrs R.H. Forester and  A.J.
Senechal, and Drs. L.W. Rust and L.L. Altpeter.


The  contributions  and advice of Mr. A.J. Steffen of Purdue University,
Mr. W.H. Miedaner of Glebe Engineering, Mr. John  Macon,  and  Dr.  H.O.
Halverson  are  gratefully acknowledged.  Also, James and Paula Wells of
Bell, Galyardt, and Wells  made  invaluable  contributions  in  numerous
telephone conversations.

Special  thanks  are due Mr. Jeffery D. Denit, Project Officer, Effluent
Guidelines Division for his guidance in the direction of the program and
for his invaluable help in carrying out  all  aspects  of  the  research
program.


Intra-agency  review,  analysis  and assistence was provided by the Meat
Products Working Group/Steering Committee comprised of the following EPA
personnel.  Mr. George Webster, Effluent Guidelines Division   (Chairman)
Mr.  Jeffery  D.  Denit, EGD, Project Officer, Mr. George Keeler, Office
of Research S Development, Mr. Jack  Witherow,  Officer  of  Research  &
Development,  Mr.  Gary  Polvi,  EPA,  Region VIII, Mr. William Sonnett,
Office of Enforcement and General Counsel, Mr. Taylor Miller, Office  of
General Counsel, Mr. Swep Davis, Office of Planning and Evaluation.

The  cooperation  of  the  meat packing industry is greatly appreciated.
The American Meat  Institute,  the  National  Independent  Meat  Packers
Association  and  the  Western  States  Meat Packers Association deserve
special mention, as dc many  companies  that  provided  information  and
cooperated in plant visits and sampling programs.

Various  Regional  EPA  offices  were most helpful in arranging for site
visits.  The plant data provided by Dr. Win. Garner and Mr.  Ron  Wantock
of the Region VII office in Kansas City were especially appreciated.
                                   155

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The  help  of  Dr.  Dwight Ballinger of EPA in Cincinnati in establishing
sampling and testing procedures used for the field verification  studies
was also appreciated.

Various  offices  in  the United States Department of Agriculture, espe-
cially the Meat and Poultry Inspection  Division,  and  many  state  and
local  agencies  were  also  most helpful.  Among these, special mention
should go to the Iowa  Water  Quality  Commission,  the  state  of  Ohio
Environmental  Protection  Administration,  and  the  City and County of
Denver Water and Sanitation District.

Special thanks also go to Mr. Ross Frazier of the  Minnesota  Department
of Health for periodically running duplicate sets of BOD5 analyses.


The  diligence  and  patience of Mrs. Pearl Smith in helping to edit and
produce this manuscript is gratefully acknowledged.
                                   156

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                             SECTION XIII

                               REFERENCES


1.  Livestock Slaughter, Annual Summary 1972, Statistical Reporting
    Service, U.S. Department of Agriculture, Washington, April 1973.

2.  The Cost of Clean Water, Industrial Waste Profile No. 8, Meat
    Products, U.S. Department of the Interior, Federal Water Pollution
    Control Administration, U.S. Government Printing Office, Washington.

3.  Pilney, J.P., Halvorson, H.O., and Erickson, E.E., Industrial Waste
    Study of the Meat Products Industry, Environmental Protection
    Agency, Contract No. 68-01-0031.

4.  Standard Industrial Classification Manual, Executive Office of the
    President, office of Management and Budget, U.S. Government
    Printing Office, Washington, 1972.

5.  U.S. Industrial Outlookk, 1973, with Projections to  1980, U.S.
    Department of Commerce, U.S. Government Printing Office, Washington.

6.  Macon, John A., Ccte, Daniel N., Study of Meat Packing Wastes in
    North Carolina, Part I, Industrial Extension Service, School of
    Engineering, North Carolina State College, Raleigh, August 1961.

7.  Kerrigan, James E., Crandall, Clifford J., Rohlich, Gerard A.,
    The Significance of Waste Waters from the Meat Industry as Related
    to the Problems of Eutrophication, American Meat Institute, Chicago,
    November 1970.

8.  Industrial Waste Water Control: Chemical Technology, Volume 2,
    C. Fred Gurnham, Ed., Academic Press, New York, 1965.

9.  Wells, W. James, Jr., "How Plants Can Cut Rising Waste Treatment
    Expense", The National Provisioner  (July 4, 1970).

10. Miedaner, W.H., "In-Plant Waste Control", The National Provisioner
    (August 19, 1972) .

11. Witherow, Jack L., Yin, S.C., and Farmer, David M., National Meat-
    packing Waste Management Research and Development Program,
    Robert S. Kerr Environmental Research Lab., EPA, Ada, Oklahoma, 1973.

12. Elimination of water Pollution by packinghouse Animal Paunch and
    Blood, Environmental Protection Agency, U.S. Government Printing
    Office, Washington, November 1971.
                                  157

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13  Personal communication, W.H.  Miedaner, 1973.

14.  Basics of Pollution Control,  Gurnham & Associates, prepared for
    Environmental Protection Agency, Technology Transfer Program,
    Kansas City, Mo., March 7-8,  1973, Chicago, Illinois.

15.  An Industrial Waste Guide to the Meat Industry, U.S. Department of
    Health, Education, and Welfare, Washington, revised 1965.

16.  Public Health Service Drinking Water Standards, Revised  1962, U.S.
    Department of Health, Education and Welfare,  U.S. Public Health
    Service Publication No. 956,  U.S. Government Printing Office,
    Washington, 1962.

17.  Steffen, A.J., In-Plant Modifications to Reduce Pollution and
    Pretreatment of Meat Packing Waste Waters for Discharge  to Municipal
    Systems, prepared for Environmental Protection Agency Technology
    Transfer Program, Kansas City, Missouri, March 7-8, 1973.

18.  Water Quality Improvement by Physical and Chemical Processes,
    Earnest F. Gloyna and W. Wesley Eckenfelder, Jr., Eds.,  University
    of Texas Press, Austin, 1970.

19.  Telephone communication with M. Hartman, Infilco  Division, Westing-
    house, Richland, Virginia, May 1973.

20.  Rosen, G.D., "Profit from Effluent", Poultry Industry (April 1971).

21.  Upgrading Meat Packing Facilities to Reduce Pollution: Waste
    Treatment Systems, Bell, Galyardt, Wells, prepared for Environmental
    Protection Agency Transfer Program, Kansas City,  Missouri, March  7-8,
    1973, Omaha.

22.  "Direct Oxygenaticn of Waste Water", Chemical  Engineering  (November  29,
    1971) .

23.  Gulp, Russell L. , and Gulp, Gordon L., Advanced  Waste Water  Treatment,
    Van Nostrand Reinhold Company, New York, 1971.

2<4.  Babbitt, Harold  E., and Baumann,  E. Robert, Sewerage and Sewage
    Treatment, Eighth ed., John Wiley & Sons, Inc.,  London,  1967.

25.  Fair, Gordon Maskew, Geyer, John  Charles, and  Okun,  Daniel
    Alexander, Water and Waste Water  Engineering:  Volume 2.  Water
    Purification and Waste Water Treatment and Disposal, John Wiley  &
    Sons, Inc., New  York,  1968.

26. Personal communication, Thor Alexander and Gary  Glazer,  1973.
                                   158

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27.  Fair,  Gordon Maskew, Geyer, John Charles, and Okun, Daniel
    Alexander, Water and Waste Water Engineering:  Volume 1.  Water
    Supply and Waste Water Removal, John Wiley & Sons, Inc., New York,
    1966.

28.  Eckenfelder, W. Wesley, Jr., Industrial Water Pollution Control,
    McGraw-Hill Bock Company, New York, 1966,

29.  Personal communication, C.E. Clapp, United States Department of
    Agriculture, Agricultural Research Service, University of Minnesota,
    Minneapolis, May 1973,

30.  Eliassen, Rolf, and Tchobanoglous, George, "Advanced Treatment
    Processes, Chemical Engineering   (October 14, 1968).

31.  Knowles, Chester I., Jr., "Improving Biological Processes",
    Chemical Engineering/Deskbook Issue (April 27, 1970).

32.  Personal Communication, H.o. Halvorson, May 1973.

33.  McGraw-Hill's 1972 Report on Business & the Environment,
    Fred C. Price, Steven Ross and Robert L. Davidson, Eds,,
    McGraw-Hill Publications Co., New York, 1972.

34.  Rickles, Robert N., Membranes, Technology and Economics, 1967,
    Noyes Development Corporation, Park Ridge, New Jersey.

35.  Financial Facts About the Meat Packing Industry,  1971, American
    Meat Institute, Chicago, August 1972.

36.  "Survey of Corporate Performance: First Quarter 1973",  Business
    Week,  p. 97  (May 12, 1973) .

37.  1967 Census of Manufactures, Bureau of the Census, U.S. Department
    of Commerce, U.S. Government Printing Office, Washington, 1971.
38.  Witherow, Jack L., "Small Meat Packers Wastes Treatment Systems,"
    presented at the 4th National Symposium on Food Processing Wastes,
    Syracuse, New York, March 26^28, 1973.

39.  McCarty, P.L., "Anaerobic Waste Treatment Fundamentals—Part Two,
    Chemistry and Microbiology," Public Works, 95, 123 (October 1964).

40.  Elimination of Water Pollution by Packinghouse Animal Paunch and Blood,
    by Beefland International, Inc., for EPA, Project #12060 FDS, November
    1971.

41.  Goodrich, R. D., and Meiske, J. C., The Value of  Dried  Rumen Contents
    As A ration for Finishing Steers, University of Minnesota Department
    of Animal Science in cooperation with Agricultural Extension Service
                                   159

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    and Agricultural Experiment Station, report B-124, 1969.

42. Pilot Plant Installation for Fungal Treatment of Vegetable Canning
    Wastes, by the Green Coant Company, for EPA, Grant No. 12060 EDZ,
    August 1971.

43. Church, Brooks D., Erickson, E. E., and Widmer, Charles M., "Fungal
    Digestion of Food Processing Wastes," Food Technology, 27, No. 2,

44. Preproposal to EPA, Ada, Oklahoma:  "Conversion of Rumen Contents of
    Beef Cattle to Fungal Protein," North Star Research and Development
    Institute, May 1972.

45. Chittenden, Jimmie A., and Wells,  W. James, Jr.,  "BOD Removal and
    Stabilization of Anaerobic Lagoon  Effluent Using  a Rotating Biological
    Contactor," presented at the 1970  Annual Conference, Water Pollution
    Control Federation, Boston.

46. Private communication from Geo. A. Hormel & Company, Austin,
    Minnesota, 1973.


47. U. S. Environmental Protection Agency, "Nitrification-
    Denitrification Facilities," Technology Transfer, August,  1973.
                                   160

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                              SECTION XIV

                                GLOSSARY


Abattoir:  A slaughterhouse.

"Act":   The Federal Viater Pollution Control Act Amendments of 1972.

Activated Sludge Process:  Aerated basin in which waste waters are
mixed with recycled biologically active sludge for periods of about
six hours.

Aerated:   The introduction and intimate contacting of air and a
liquid by mechanical means such as stirring, spraying, or bubbling.

Aerobic:   Living or occurring only in the presence of dissolved or
molecular oxygen.

Algae:   Major group of lower plants, single and multi-celled,
usually aquatic and capable of synthesizing their foodstuff by
photosynthesis.

Ammonia Stripping:   Ammonia removal from a liquid, usually by intimate
contacting with an ammonia^free gas such as air.

Anaerobic:   Living or active only in the absence of free oxygen.

Bacteria:   Primitive plants, generally free of pigment, which
reproduce by dividing in one, two, or three planes.  They occur as
single cells, chains, filaments, well-oriented groups or amorphous
masses.  Most bacteria do not require light, but a limited number
are photosynthetic and draw upon light for energy.  Most bacteria
are heterotrophic  (utilize organic matter for energy and for
growth materials), but a few are autotrophic and derive their bodily
needs from inorganic materials.

Barometric Condenser:   A mechanical device to condense vapors by the
direct and intimate contacting of the vapors and the cooling water.

Bedding:   Material, usually organic, which is placed on the floor
surface of livestock buildings for animal comfort and to absorb urine
and other liquids, and thus promote cleanliness in the building.
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Biological Oxidation:   The process whereby,  through the activity of
living organisms in an aerobic environment,  organic matter is
converted to more biologically stable matter.

Biological Stabilization:   Reduction in the net energy level of
organic matter as a result of the metabolic activity of organisms,
so that further biodegradation is very slow.

Biological Treatment:   Organic waste treatment in which bacteria
and/or biochemical action are intensified under controlled conditions.

Blood Water  (Serum):    Liquid remaining after coagulation of the blood.

Blowdown:  A discharge of water from a system to prevent a buildup
of dissolved solids in a boiler.

BODS:   A measure of the oxygen consumption by aerobic organisms
over a 5 day test period at 20°C.  It is an indirect measure of
the concentration of biologically degradable material present in
organic wastes contained in a waste stream.

Capacity-Cost Relationship:   The variation of investment cost for
equipment or a total plant as a function of  its size or capacity.

Capacity-Ratio Exponent  (n):   In capacity-cost relationships, cost
usually increases at a slower rate than capacity.  The ratio of
capacities of an exponential power  (n) in estimating investment cost
at one capacity, given the cost at a different capacity: e.g.,
 (C!/C2)n  (cost of C2 = Cost of C1.

Carbon Adsorption:   The separation of small waste particles and
molecular species, including color and odor contaminants, by attach-
ment to the  surface and open pore structure of carbon granules or
powder.  The carbon is usually "activated", or made more reactive
by treatment and processing.

Casings:   The cleaned intestines of cattle, hogs, or sheep used  as a
case for processed meat such as sausage.

Category and Subcategory:   Divisions of a particular industry which
possess different traits that affect raw waste water quality.

Chemical Precipitation:    A waste treatment  process whereby substances
dissolved in the waste water stream are rendered  insoluble and  form
a solid phase that settles out or can fce removed  by flotation
techniques.

Chitterling:   Large intestine of hogs.
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Clarification:   Process of removing undissolved materials from a
liquid.  Specifically, removal of solids either by settling or
filtration.

Clarifier:   A settling basin for separating settleable solids from
Cm:   Centimeter.

Coagulant:   A material, which, when added to liquid wastes or water,
creates a reaction which forms insoluble floe particles that adsorb
and precipitate colloidal and suspended solids.  The floe particles
can be removed by sedimentation.  Among the most common chemical
coagulants used in sewage treatment are ferric sulfate and alum.

COD-Chemical Oxygen Demani:   An indirect measure of the biochemical
load imposed on the oxygen resource of a body of water when
organic wastes are introduced into the water.  A chemical test is
used to determine COD of waste water.

Composting:   Present-day composting is the aerobic, thermophilic
decomposition of organic wastes to a relatively s#able humus.  The
resulting humus may contain up to 25% dead or living organisms and is
subject to further, slower decay but should be sufficiently stable
not to reheat or cause odor or fly problems.  In composting, mixing
and aeration are provided to maintain aerobic conditions.  The
decomposition is done by aerobic organisms, primarily thermophilic
bacteria, actinomycetes and fungi.  Heat generated provides the
higher temperatures the microorganisms require.

Contamination:   A general term signifying the introduction into water
of microorganisms, chemical, organic, or inorganic wastes, or sewage,
which renders the water unfit for its intended use.

Cracklings:   The crisp solid residue left after the fat has been
separated from the fibrous tissue in rendering ^ard or tallow.

Curing:   A process, method, or treatment involving aging, seasoning,
washing, drying, injecting, heating, smoking or otherwise treating a
product, especially meat, to preserve, perfect, or ready it for use.

Denitrification:   The process involving the facultative conversion
by anaerobic bacteria of nitrates into nitrogen and nitrogen oxides.

Digestion:  Though "aerobic" digestion is used, the term digestion
commonly refers to the anaerobic breakdown of organic matter in water
solution or suspension into simpler or more biologically stable
compounds or both.  Organic matter may be decomposed to soluble
organic acids or alcohols, and subsequently converted to such gases
as methane and carbon dioxide.  Complete destruction of organic solid
materials by bacterial action alone is never accomplished.
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Dissolved Air Flotation:   A process involving the compression of air
and liquid, mixing to super-saturation, and releasing the pressure to
generate large numbers of minute air bubbles.  As the bubbles rise to
the surface of the water, they carry with them small particles that
they contact.  The process is particularly effective for grease removal.

Dissolved Oxygen:   The oxygen dissolved in sewage, water, or other
liquid, usually expressed as milligrams per liter or as percent of
saturation.

Effluent:   Liquid which flows from a containing space or process unit.

Electrodialysis:   A physical separation process which uses membranes
and applied voltages to separate ionic species from water.

Eutrophication:   Applies to lake or pond - becoming rich in dissolved
nutrients, with seasonal oxygen deficiencies.

Evapotranspiration:   Loss of water from the soil, both by evaporation
and by transpiration from the plants growing thereon.

Extended Aeration:   A  form of the activated sludge process except
that the retention time of waste waters is one to three days.

Facultative Bacteria:   Bacteria which can exist and reproduce under
either aerobic or anaerobic conditions.

Facultative Decomposition:   Decomposition of organic matter by
facultative microorganisms.

Feed:   A material which flows into a  containing space or process unit.

Filtration:   The process of passing a liquid through a porous medium
for the removal of suspended material  by a physical straining action.

Floe:   A mass formed by the aggregation of a number of fine suspended
particles.

Flocculation:   The  process of forming larger masses from a large
number of finer suspended particles.

Floe Skimmings:   The flocculent mass  formed on a quieted liquid
surface and removed  for use, treatment, or disposal.

Full-Line Plant:   A packinghouse that slaughters and produces a
substantial quantity cf processed meat products.
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Green Hides:   Animal hides that may have been washed and trimmed,
but have not been treated, cured, or processed in any manner.

Hectare:   A metric measure of area equivalent to 100 ares (also metric)
and 2.47 acres.

Hydrolyzing:   The reaction involving the decomposition of organic
materials by interaction with water in the presence of acids or
alkalies.  Hog hair and feathers, for example, are hydrolyzed to
a proteinacous product that has some feed value.

Influent:   A liquid which flows into a containing space or process unit.

Ion Exchange:   A reversible chemical reaction between a solid and a
liquid by means of which ions may be interchanged between the two.
It is in common use in water softening and water deionizing.

Kg:   Kilogram or 1000 grams, metric unit of weight.

Kjeldahl Nitrogen:   A measure of the total amount of nitrogen in the
ammonia and organic fcrrrs in waste water.

KWH:   Kilowatt-hours, a measure of total electrical energy consumption.

Lagoon:   An all-inclusive term commonly given to a water impoundment
in which organic wastes are stored or stabilized or both.

Locker Plant:   Very small meat packing plant that slaughters
animals and may produce processed meat products, it stores meat in
frozen form for its customers.

LWK:   Live weight killed, a measure of production in a meat packing
plant, commonly expressed in thousands of kilograms or pounds per day.

M:   Meter, metric unit of length.

Micrometer:   Also micron, a metric measure of length equal to one
millionth of a meter or 39 millionths of an inch.

Mm:   Millimeter = 0.001 meter.

Mg/1:   Milligrams per liter; approximately equals parts per million;
a term used to indicate concentration of materials in water.

MGD or MGPD:   Million gallons per day.

Microstrainer/microscreen:   A mechanical filter consisting of a
cylindrical surface of metal filter fabric with openings of 20-60
micrometers in size.
                                  165

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Municipal Treatment:   A city or community-downed waste treatment plant
for municipal and, possibly, industrial waste treatment.

New Source:   Any building, structure, facility, or installation from
which there is or may be a discharge of pollutants and whose con-
struction is commenced after the publication of the proposed
regulations.

Nitrate, Nitrite:   Chemical compounds that include the NO3- (nitrate)
and NO2- (nitrite) ions.  They are composed of nitrogen and oxygen,
are nutrients for growth of algae and other plant life, and contribute
to eutrophication.

Nitrification:   The process of oxidizing ammonia by bacteria into
nitrites and nitrates.

No Discharge:   No discharge of effluent to a water course.  A
system of land disposal with no run-off or total recycle of the
waste water may be used to achieve it.

Non-Water Quality:   Thermal, air, noise and all other environmental
parameters except water.

Offal:   The parts of a butchered animal removed in eviscerating and
trimming that may be used as edible products or in production of
inedible by-products.

Off-Gas:   The gaseous products of a process that are collected for
use or more typically vented directly, or through a flare,  into
the atmosphere.

Organic Content:   Synonymous with volatile solids except  for small
traces of some inorganic materials such as calcium carbonate which
will lose weight at temperatures used in determining volatile solids.

Oxidation Lagoon:   Synonymous with aerobic or aerated  lagoon.

Oxidation Pond:   Synonymous with aerobic lagoon.

Packinghouse:   Meat packing plant that slaughters animals and also
produces manufactured mea#  products such as weiners, sausage, canned
meats, cured products, etc.

Paunch:   The first stomach, or rumen of cattle, calves, and sheep.
The contents are  sometimes  included in the term.

Paunch manure:    Contents  of the paunch.
                                  166

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Peck:   The second stomach of a ruminant.

Pens (Holding Pens):    The area or building for holding live animals
at meat packing plants prior to slaughter.

Percolation:   The movement of water through the soil profile.

pH:   A measure of the relative acidity or alkalinity of water.  A
pH of 7.0 indicates a neutral condition.  A greater pH indicates
alkalinity and a lower pH indicates acidity.  A one unit change in
pH indicates a ten fold change in the concentration of hydrogen
ion.

Pickle Solution:   A water solution that may contain salt, sugar,
curing or pickling agents, preservatives, and other chemicals.  It
is used for injection or soaking of meat to prepare finished meat
products.

Pollutant:   A substance which taints, fouls, or otherwise renders
impure or unclean the recipient system.

Pollution:   The presence of pollutants in a system sufficient to
degrade the quality of the system.

Polishing:   Final treatment stage before discharge of effluent to a
water course, carried out in a shallow, aerobic lagoon or pond,
mainly to remove fine suspended solids that settle very slowly.
Some aerobic microbiological activity also occurs.

Polyelectrolyte Chemicals:   High molecular weight substances which
dissociate into ions when in solution; the ions either being bound
to the molecular structure or free to diffuse throughout the solvent,
depending on the sign of the ionic charge and the type of electrolyte.
They are often used as flocculating agents in waste water treatment,
particularly along with dissolved air flotation.

Ponding:   A waste treatment technique involving the actual holdup of
all waste waters in a confined space with evaporation and percolation
the primary mechanisms operating to dispose of the water.

Ppm:   Parts per million, a measure of concentration, expressed
currently as mg/1.

Pretreatment:   Waste Water treatment located on the plant site and
upstream from the discharge to a municipal treatment system.

Primary Waste Treatment:   In-Plant by-product recovery and waste water
treatment involving physical separation and recovery devices such as
catch basins, screens, and dissolved air flotation.
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Processing:   Manufacture of sausages, hams, canned meats, smoked meat
products, etc., from fresh meat cuts or ground meats.

Process Water:   All water that comes into direct contact with the
raw materials, intermediate products, final products, by-products,
or contaminated waters and air.

Raceway:   Circular shaped vat containing brine, agitated by a
paddle wheel and used for brine curing of hides.

Raw Waste:   The waste water effluent from the in-plant primary waste
treatment system.

Recycle:   The return of a quantity of effluent from a specific unit
or process to the feed stream of that same unit.  This would also
apply to return of treated plant waste water for several plant usesf

Rendering:   Separation of fats and water from tissue by heat or
physical energy.

Return-on-Assets  (ROA):   A measure of potential or realized profit as
a percent of the total assets  (or fixed assets) used to generate
the profit.

Return-on-Investment  (ROI):   A measure of potential or realized profit
as a percentage of the investment required to generate the profit.

Reuse:   Water reuse, the subsequent use of water following an
earlier use without restoring it to the original quality.

Reverse Osmosis:   The physical separation of substances  from a
water stream by reversal of the normal osmotic process; i.e., high
pressure,  forcing water through a semi-permeable membrane to the
pure water side leaving behind more concentrated waste streams.

Riprap:   A foundation or sustaining wall usually of stones and brush,
so placed on an embankment or a lagoon to prevent erosion.

Rotating Biological Contractor:   A waste treatment  device involving
closely  spaced light-weight disks which are rotated  through the
waste water allowing  aerobic microflora to  accumulate on  each disk
and thereby achieving a reduction in  the waste content.
                                                      »

Rumen:   The large first compartment of the stomach  of a  ruminant;
see paunch.

Sand Filter:   A  filter device incorporating  a bed of sand that,
depending  on design,  can be used in  secondary or tertiary waste
                                   168

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treatment.

Secondary Processes:   Edible and inedible rendering and the processing
of blood, viscera, hide, and hair.

Sedimentation Tank:   A tank or basin in which a liquid (water, sewage,
liquid manure)  containing settleable suspended solids is retained
for a sufficient time so part of the suspended solids settle out by
gravity.  The time interval that the liquid is retained in the tank
is called "detention period".  In sewage treatment, the detention
period is short enough to avoid putrefaction.

Secondary Treatment:   The waste treatment following primary in-
plant treatment, typically involving biological waste reduction
systems.

Semipermeable Membrane:   A thin sheet-like structure which permits
the passage of solvent but is impermeable to dissolved substances.

Septic:   A condition characterized by or producing bacterial
decomposition;  anaerobic.
Settling Tank:    Synonymous with "Sedimentation Tank".

Sewage:   Water after it has been fouled by various uses.   From the
standpoint of source it may be a combination of the liquid or water-
carried wastes from residences, business buildings, and institutions,
together with those from industrial and agricultural establishments,
and with such groundwater, surface water, and storm water as may be
present.

Shock Load:   A quantity of waste water or pollutant that greatly
exceeds the normal discharged into a treatment system, usually
occurring over a limited period of time.

Slaughterhouse:   Meat packing plant that slaughters animals to produce
fresh meats.  It does not produce manufactured meat products such as
weiners, sausage, canned meats, etc.

Sludge:   The accumulated settled solids deposited from sewage or other
wastes, raw or treated, in tanks or basins, and containing more or
less water to form a semi-liquid mass.

Slurry:   A solids-water mixture, with sufficient water content to
impart fluid handling characteristics to the mixture.

Stick or Stickwater:  , The concentrated  (thick) liquid product from
evaporating the tankwater from rendering operations.  It is added
to solids and may be further dried for feed ingredients.
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Stoichiometric Amount:   The amount of a substance involved in a
specific chemical reaction, either as a reactant or as a reaction
product.

SS:   suspended solids; solids that either float on the surface of,
or are in suspension, in water; and which are largely removable by
laboratory filtering as in the analytical determinate of SS content
of waste water.

Surface Water:   The waters of the United States including the
territorial seas.

Tankwater:   The water phase resulting from rendering processes,
usually applied to wet rendering.

Tertiary Waste Treatment:   Waste treatment systems used to treat
secondary treatment effluent and typically using physical-chemical
technologies to effect waste reduction.  Synonymous with "Advanced
Waste Treatment",

Total Dissolved Solids (TDS) :   The solids content of waste water that
is soluble and is measured as total solids content minus the
suspended solids.

Tripe:   The edible product prepared from the walls of the paunch or
rumen.

Viscera:   All internal organs of an animal that are located  in the
great cavity of the trunk proper.

Zero Discharge:   The discharge of no pollutants in the waste water
stream  of a plant that is discharging into a receiving body of water.
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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

bbreviation
ac
ac ft
BTU
BTU/lb
cfm
cfs
cu ft
cu ft
cu in
°F
ft
gal
gpm
hp
in
in Hg
Ib
mgd
mi
psig (0.
sq ft
sq in
t
y
by
Conversion
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
06805 psig + 1)*
0.0929
6.452
0.907
0.9144

Abbreviatioi
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
km
atm
sq m
sq cm
kkg
m
To Obtain (Metric Units)

       Metric Unit
hectares
cubic meters
kilogram-calories
kilogram calories/kilogram
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigcade
meters
liters
liters/second
kilowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres (absolute)
square meters
square centimeters
metric tons (1000 kilograms)
meters
*Actual conversion, not a multiplier
                                              171

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