EPA 440/1-77/084
         Supplement For
        PRETREATMENT
             to the
     Development Document
            for the
       STEAM ELECTRIC
     POWER GENERATING
    Point Source Category
             .^osr^

  U.S. ENVIRONMENTAL PROTECTION AGENCY
            APRIL 1977

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      SUPPLEMENT FOR PRETREATMENT
      TO THE DEVELOPMENT  DOCUMENT
                for the
    STEAM ELECTRIC POWER GENERATING
         POINT SOURCE CATEGORY
           Douglas M. Costle
             Admini strator
      Andrew W. Breidenbach, Ph.D.
        Assistant Administrator
   for Water and Hazardous Materials

            Eckardt C. Beck
   Deputy Assistant Administrator for
      Water Planning and Standards
                       ri
           Robert B. Schaffer
 Director, Effluent Guidelines Division

                John Lum
            Project Officer
               April 1977
      Effluent Guidelines Division
Office of Water and Hazardous Materials
  U.S. Environmental Protection Agency
        Washington, D.C.   20460
                  SB

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                          ABSTRACT
This document presents the findings of an extensive study of
that section of the Steam Electric Power Generating Industry
which  discharges  industrial  wastes  to   publicly   owned
treatment   works   (POTW).    Its  purpose  is  to  develop
pretreatment standards to implement section  307 (b)  of  the
Federal  Water  Pollution  Control Act Amendment of 1972 for
the Existing Power Plants.

Pretreatment standards, recommended in Section  II  of  this
report set forth the degree of effluent reduction achievable
through  the  application  of  control  technology currently
available for those pollutants which are determined  not  to
be  susceptible  to  treatment  by  a  POTW  or  which would
interfere  with  the  operation  of   such   works.    These
pretreatment  standards  set  forth  the  degree of effluent
reduction achievable through application  of  the  available
demonstrated   control   technology,   processes,   operating
methods, or other alternatives.   These  standards  must  be
achieved  no  later  than  three   (3)  years from the date of
promulgation.

Supporting data and rationale for development  of  pretreat-
ment standards are contained in this report.
                            iii

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                      LIST OF CONTENTS


                                                     Page

ABSTRACT                                              iii

TABLE OF CONTENTS                                       V

LIST OF FIGURES                                        ix

LIST OF TABLES                                         xi



I.       CONCLUSIONS                                    1

II.      RECOMMENDATIONS                                3

III.     INTRODUCTION                                   9

         General Background                             9

         Purpose and Authority                         10

         Scope of Work and Technical Approach          10

         General Description of the Industry           13

         Process Description                           13

         Publicly-Owned Treatment Works  (POTW)         22

IV.      INDUSTRY CATEGORIZATION                       25

         Introduction                                  25

         Industry Categorization                       25

         Factors Considered                            25

              Age                                      25
              Size                                     26
              Fuel                                     26
              Geography                                26
              Mode of Operation                        28
              Raw Water Quality                        28
              Volume of Water Used                     28
              Pretreatment Technology                  28

V.       WATER USE AND WASTE CHARACTERIZATION          29

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         Introduction                                  29

         Principles of Operation of steam Electric
         Power Plant                                   29

         Water Use and Waste characterization by
         Category                                      32

         Condenser Cooling Water                       34

         Water Treatment                               42

         Demineralizer Regenerant Wastes               47

         Boiler Slowdown                               49

         Maintenance Cleaning                          53

         Ash Handling Systems                          58

         Air Pollution Control Equipment               65

         The POTW Process                              70

         Flows of POTW Receiving Steam Electric
         Wastewaters                                   77

VI.      CONSIDERATION OF POLLUTANT PARAMETERS         85

         Introduction                                  85

         The Consideration of Pollutant
         Parameters                                    85

         Properties of Pollutant Parameters
         Considered                                    86

VII.     TREATMENT AND CONTROL TECHNOLOGY             105

         Introduction                                 105

         End-of-Pipe Treatment Technology             105

         Treatment of Major Pollutants                106

         End-of-Pipe Technology for Major
         Waste Streams                                114

         Water Management                             120

         In-Plant Control Techniques                  121
                             vi

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         Material Substitution                         121

         Water Conservation and Wastewater Reuse       125

VIII.    COST, ENERGY AND OTHER NON WATER QUALITY
         ASPECTS                                       129

         Introduction                                  129

         Cost Reference and Rationale                  130

         Costs for Pretreatment                        133

         Levels of Pretreatment                        131

         Cost Estimates                                1UU

         Ultimate Disposal                             151

         Energy Considerations                         155

IX.      BEST PRACTICABLE PRETREATMENT TECHNOLOGY      157

X.       ACKNOWLEDGEMENTS                              163

XI.      REFERENCES                                    165

XII.     GLOSSARY                                      168

APPENDIX A - STATISTICAL ANALYSIS OF HISTORICAL
             DATA                                      179

APPENDIX B - WATER GLOSSARY                            221

APPENDIX C - METRIC UNITS CONVERSION TABLE             253
                            VII

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                      LIST OF FIGURES


                                                     Page

III-l    Principal Fuel Use by Number                  16

III- 2    Principal Fuel Use by Megawatts               17

III-3    Year of Construction by Number                18

    H    Year of Construction by Megawatt              19
III- 5    Process Flow Diagram Steam Electric
         Power Industry                                21

III- 6    Wastewater Treatment Sequence                 23

V-l      Typical Boiler for Coal-Fired Furnace         31

V-2      Single-pass Condenser                         33

V-3      Fossil-Fueled Steam Electric Power
         Plant - Typical Flow Diagram                  35

V-U      Once-Through and Recirculating
         Cooling Systems                               38

V-5      Diagram of Wet Induced - Air Cooling
         Tower                                         3 9

V-6      Natural Draft Wet Cooling Tower
         (Counter Flow)                                40

V-7      Commonly Used Makeup Water
         Treatment Methods                             U5

V-8      Flow Diagram for Recirculating
         Bottom Ash System                             59

V-9      Flow Diagram for Air Pollution Control
         Scrubbing System                              68

V-10     Flow Diagram of Secondary Treatment
         Methods                                       7 H

V-11     Wastewater Treatment Flow Diagram             75

V-12     Flow Diagram for Sludge Treatment             76

V-13     Flow Diagram of Nitrification -
         Denitrification Process                       79

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VIII-1   Model Waste Pretreatment Plant - 25 MW
         Generating Facility                          143

VIII-2   Model Waste Pretreatment Plant - 500 MW
         Generating Facility                          146

VIII-3   Cooling Water System Slowdown Treatment
         for Level D Pretreatment                     153

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                       LIST OF TABLES
                                                   Page
III-l    Total Steam Electric Plants
         in the Contiguous United States             14

III- 2    Steam Electric Plants Discharging
         to Municipal Sewers in the Contiguous
         United States                               15

IV- 1     Power Plant Waste Types                     27

V-1      Raw Waste Flows and Loadings -
         Condenser Cooling Systems                   U3

V-2      Raw Waste Flows and Loadings -
         Water Treatment                             50

V-3      Effluent Flows and Loadings -
         Water Treatment                             52

V-4      Raw Waste Flows and Loadings -
         Boiler Slowdown                             54

V-5      Raw Waste Flows and Loadings -
         Maintenance Cleaning                        57

V-6      Ash Disposal Methods                        60

V-7      Raw Waste Flows and Loadings -
         Ash Handling                                63

V-8      Effluent Flows and Loadings -
         Ash Handling                                6U

V-9      Power Plant and POTW Flows                  80

V-10     Raw Waste Flows and Loadings -
         Combined Discharge to POTW                  81

V-11     Comparison of Parameter Values
         Plant Raw Wastes                            83

VII-1    End-of -pipe Treatment Methods              107

VII-2    Solid/Liquid Separation Systems            110

Vll-3    Treatment of Major Pollutants              112

    U    Typical Composition of Boiler Chemical

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         Cleaning Wastes                            119

VII-5    Typical Composition of Boiler Fireside
         Wash Wastes                                119

VII-6    Recovery Processes for Flue Gas
         Desulfurization Systems                    126

VIII-1   Wastewater Treatment Costs and Resulting
         Waste-load Characterization for Typical
         Plant                                      135

VIII-2   Wastewater Treatment Costs and Resulting
         Waste-load Characteristics for Typical     136
         Plant

VIII-3   Summary of Capital Costs Oil and Gas
         Fired Plants - 25 MW Plant                 137

VIII-4   Wastewater Treatment Cost and Resulting
         Waste-load Characteristics for Typical
         Plant                                      141

VIII-5   Wastewater Treatment Costs and Resulting
         Waste-load Characteristics for Typical
         Plant                                      142

VIII-6   Summary of Capital Costs Coal Fired
         Plant                                      145

VIII-7   Assumed Unit Costs                         147

VIII-8   Operating Costs - Pretreatment of Low
         Volume and Metal Cleaning Wastes           149

VIII-9   Estimated Capital Costs - Chemical
         Works Pretreatment Plant Level C           152

VIII-10  Estimated Capital Cost - Cooling Water
         System Slowdown Treatment                  154

VIII-11  Estimated Capital Costs - Cooling Water
         System Slowdown Treatment                  154
                            Xll

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                         SECTION I

                         CONCLUSION
An engineering evaluation of steam electric power generating
plants  that  discharge  all  or  a portion of their aqueous
wastes  to  publicly-owned  treatment   works   (POTW)    was
conducted to establish the basis for pretreatment standards.
For the purpose of establishing such standards it was deemed
practical  to  divide  the wastes from power plants into the
following waste-types:

    o    Condenser Cooling System
    o    Boiler Water Treatment
    o    Boiler Slowdown
    o    Maintenance Cleaning
    o    Ash Handling
    o    Drainage
    o    Air Pollution Control Devices
    o    Miscellaneous Waste Streams

This  division  is  identical  to  that  presented  in   the
development  document  for  direct  dischargers (14) in this
industry with the deletion of Construction  Activity.   This
division  was  found  to  be valid as examination of process
characteristics  and  raw  wastes  were  not  found  to   be
significantly different from those of direct dischargers.

Conduct  of the work involved contact with 49 steam electric
power generating stations, representing 50  percent  of  the
estimated  98  stations  discharging  chemicals  wastes to a
POTW.  Engineering visits and data collection were  made  to
23  stations.   Sampling  of  raw  and pretreated wastes was
obtained from eight (8)  stations. Additionally,  prior  work
conducted  by  the  EPA, data collected in response to NPDES
and local discharge permit monitoring,  industrial  effluent
data,  and  relevant  literature  prepared  by  the  EPA and
electrical trade journals were evaluated.

Based on the above  evaluation,  the  following  conclusions
were reached:

    o    Pollutants discharged by the population  of  plants
         discharging  to  the  POTW  are similar to those of
         direct dischargers.

    o    The division of  waste  types  developed  above  is
         valid  for  the purpose of characterizing the waste
         sources.

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    o    Treatment technologies described in the development
         document for the  effluent  limitations  guidelines
         for  this  industry  are  also applicable to plants
         discharging to the POTW.

A survey of current industry practices  has  indicated  that
most  plants  provide  little  pretreatment of chemical type
wastes at the present time.  Based upon information provided
in this document  regarding  pollutant  properties  and  raw
waste  characteristics,  it  is  determined that some of the
pollutants discharged by the Steam Electric Power Generating
Point Source Category will  interfere  with  or  be  treated
inadequately by Publicly Owned Treatment Works (POTW).

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                         SECTION II

                      RECOMMENDATIONS
As  a  result  of  the findings and conclusions contained in
this report, the pretreatment standards for  existing  power
plants  in compliance with the mandates of the Federal Water
Pollution Control  Act  Amendment  of  1972  are  summarized
below:

General Unit Subcategory*

    For  the  purpose of establishing pretreatment standards
under Section 307 (b) of the Act  for  a  source  within  the
General Unit subcategory, the provisions of 40 CFR 128 shall
not  apply.   The  pretreatment  standards  for  an existing
source within the general unit  subcategory  are  set  forth
below.

     (a)   No pollutant  (or  pollutant  property)   introduced
into  a  publicly owned treatment works shall interfere with
the operation or performance of  the  works.   Specifically,
the  following  wastes  shall  not  be  introduced  into the
publicly owned treatment works:

     (1)   Pollutants which create a fire or explosion  hazard
in the publicly owned treatment works.

     (2)   Pollutants which will  cause  corrosive  structural
damage  to treatment works, but in no case pollutants with a
pH  lower  than  5.0,  unless  the  works  is  designed   to
accommodate such pollutants.

     (3)   Solid or viscous pollutants in amounts which  would
cause   obstruction   to   the  flow  in  sewers,  or  other
interference with the proper operation of the publicly owned
treatment works.

     (4)   Pollutants at  either  a  hydraulic  flow  rate  or
pollutant flow rate which is excessive over relatively short
time  periods so that there is a treatment process upset and
subsequent loss of treatment efficiency.

     (b)   In addition to the general prohibitions  set  forth
in  paragraph (a)  above,  the following pretreatment standard
establishes  the  quality  or  quantity  of  pollutants   or
pollutant properties controlled by this section which may be
introduced into a publicly owned treatment works by a source
subject to the provisions of this subpart.

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     (1)  There shall  be  no  discharge  to  publicly  owned
treatment  works  of polychlorinated biphenol compounds such
as those used for tranformer fluid.

     (2)  The quantity of copper discharged in metal cleaning
wastes to publicly owned treatment works  shall  not  exceed
the  quantity  determined  by  mulitplying the flow of metal
cleaning wastes times 1 mg/1.

     (3)  The quantity of  oil  and  grease  in  the  plant*s
combined  discharge  to  the  publicly owned treatment works
shall not exceed the quantity determined by multiplying  the
flow of the combined discharge times 100 mg/1.

     (c)  Any owner or operator of any source  to  which  the
pretreatment  standards  required by paragraph (a)  above are
applicable, shall be in compliance with such standards  upon
the   effective  date  of  such  standards.   The  time  for
compliance with standards required by  paragraph  (b)   above
shall  be  within the shortest time but not later than three
years from the effective date of such standards.

Small Unit Subcategory*

    For the purpose of establishing  pretreatment  standards
under  Section  307 (b)  of  the  Act for a source within the
Small Unit subcategory, the provisions of UO CFR  128  shall
not  apply.   The  pretreatment  standards  for  an existing
source within the  small  unit  subcategory  are  set  forth
below.

     (a)  No pollutant  (or  pollutant  property)   introduced
into  a  publicly owned treatment works shall interfere with
the operation or performance of  the  works.   Specifically,
the  following  wastes  shall  not  be  introduced  into the
publicly owned treatment works:

     (1)  Pollutants which create a fire or explosion  hazard
in the publicly owned treatment works.

     (2)  Pollutants which will  cause  corrosive  structural
damage  to treatment works, but in no case pollutants with a
pH  lower  than  5.0,  unless  the  works  is  designed   to
accommodate such pollutants.

     (3)  Solid or viscous pollutants in amounts which  would
cause   obstruction   to   the  flow  in  sewers,  or  other
interference with the proper operation of the publicly owned
treatment works.

     (4)  Pollutants at  either  a  hydraulic  flow  rate  or
pollutant flow rate which is excessive over relatively short

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time  periods so that there is a treatment process upset and
subsequent loss of treatment efficiency.

     (b)  In addition to the general prohibitions  set  forth
in  paragraph  (a) above, the following pretreatment standard
establishes  the  quality  or  quantity  of  pollutants   or
pollutant properties controlled by this section which may be
introduced into a publicly owned treatment works by a source
subject to the provisions of this subpart.
     (1)  There shall  be  no  discharge  to  publicly  owned
treatment  works  of polychlorinated biphenol compounds such
as those used for tranformer fluid.

     (2)  The quantity of copper discharged in metal cleaning
wastes to publicly owned treatment works  shall  not  exceed
the  quantity  determined  by  mulitplying the flow of metal
cleaning wastes times 1 mg/1.

     (3)  The quantity of  oil  and  grease  in  the  plant's
combined  discharge  to  the  publicly owned treatment works
shall not exceed the quantity determined by multiplying  the
flow of the combined discharge times 100 mg/1.

     (c)  Any owner or operator of any source  to  which  the
pretreatment  standards  required by paragraph (a) above are
applicable, shall be in compliance with such standards  upon
the   effective  date  of  such  standards.   The  time  for
compliance with standards required by  paragraph  (b)   above
shall  be  within the shortest time but not later than three
years from the effective date of such standards,

Old Unit Subcategory*

    For the purpose of establishing  pretreatment  standards
under  Section 307 (b) of the Act for a source within the Old
Unit subcategory, the provisions of 40  CFR  128  shall  not
apply.   The  pretreatment  standards for an existing source
within the old unit subcategory are set forth below.

     (a)  No pollutant   (or  pollutant  property)   introduced
into  a  publicly owned treatment works shall interfere with
the operation or performance of  the  works.   Specifically,
the  following  wastes  shall  not  be  introduced  into the
publicly owned treatment works:

     (1)  Pollutants which create a fire or explosion  hazard
in the publicly owned treatment works.

     (2)  Pollutants which will  cause  corrosive  structural
damage  to treatment works, but in no case pollutants with a
pH  lower  than  5»0,  unless  the  works  is  designed   to
accommodate such pollutants.

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    (3)   Solid or viscous pollutants in amounts which  would
cause   obstruction   to   the  flow  in  sewers,  or  other
interference with the proper operation of the publicly owned
treatment works.
         Pollutants at  either  a  hydraulic  flow  rate  or
pollutant flow rate which is excessive over relatively short
time  periods so that there is a treatment process upset and
subsequent loss of treatment efficiency.

    (b)   In addition to the general prohibitions  set  forth
in  paragraph (a)  above, the following pretreatment standard
establishes  the  quality  or  quantity  of  pollutants   or
pollutant properties controlled by this section which may be
introduced into a publicly owned treatment works by a source
subject to the provisions of this subpart.
    (1)   There shall  be  no  discharge  to  publicly  owned
treatment  works  of polychlorinated bi phenol compounds such
as those used for tranformer fluid.

    (2)   The quantity of copper discharged in metal cleaning
wastes to publicly owned treatment works  shall  not  exceed
the  quantity  determined  by  mulitplying the flow of metal
cleaning wastes times 1 mg/1.

    (3)   The quantity of  oil  and  grease  in  the  plant's
combined  discharge  to  the  publicly owned treatment works
shall not exceed the quantity determined by multiplying  the
flow of the combined discharge times 100 mg/1.

    (c)   Any owner or operator of any source  to  which  the
pretreatment  standards  required by paragraph  (a) above are
applicable, shall be in compliance with such standards  upon
the   effective  date  of  such  standards.   The  time  for
compliance with standards required by  paragraph   (b)  above
shall  be  within the shortest time but not later than three
years from the effective date of such standards.

Area Runoff Subcategory*

    For the purpose of establishing  pretreatment  standards
under Section 307 (b) of the Act for a source within the Area
Runoff  subcategory,  the provisions of 40 CFR 128 shall not
apply.  The pretreatment standards for  an  existing  source
within the area runoff subcategory are set forth below.

    (a)   No pollutant   (or  pollutant  property)  introduced
into  a  publicly owned treatment works shall interfere with
the operation or performance of  the  works.   Specifically,
the  following  wastes  shall  not  be  introduced  into the
publicly owned treatment works:

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    (1)  Pollutants which create a fire or explosion  hazard
in the publicly owned treatment works.

    (2)  Pollutants which will  cause  corrosive  structural
damage  to treatment works, but in no case pollutants with a
pH  lower  than  5.0,  unless  the  works  is  designed   to
accommodate such pollutants.

    (3)  Solid or viscous pollutants in amounts which  would
cause   obstruction   to   the  flow  in  sewers,  or  other
interference with the proper operation of the publicly owned
treatment works.

    (U)  Pollutants at  either  a  hydraulic  flow  rate  or
pollutant flow rate which is excessive over relatively short
time  periods so that there is a treatment process upset and
subsequent loss of treatment efficiency.

    (b)  Any owner or operator of any source  to  which  the
pretreatment  standards  required by paragraph (a) above are
applicable, shall be in compliance with such standards  upon
the effective date of such standards.

*The  definitions  of  these  subcategories  are the same as
those  used  for   the   effluent   limitations   guidelines
regulations.

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                        SECTION III

                        INTRODUCTION
General Background

The involvement of the Federal Government in water pollution
control  dates  back to 1948 when Congress enacted the first
comprehensive measure aimed specifically  at  this  problem.
At  that  time  the Surgeon General, through the U.S. Public
Health Service, was authorized to assist states  in  various
ways  to  address  the problem.  The emergence of a national
water  pollution  control  program  came  about   with   the
enactment of the Water Pollution Control Act of 1956  (Public
Law  84-660).   To  date  this  law  remains  the  basic law
governing water pollution.  It establishes the basic  system
of   technical   and  financial  assistance  to  states  and
municipalities, as well as enforcement procedures  by  which
legal steps can be initiated against polluters.

The  present  program dates back to the Water Quality Act of
1965 and the Clean Water Restoration Act of 1966.  Under the
1965 Act,  states  were  required  to  adopt  water  quality
standards  for  interstate  waters,  and  to  submit  to the
Federal Government, for approval,  plans  to  implement  and
enforce  these  standards.   The 1966 Act authorized Federal
participation in construction of  sewage  treatment  plants.
On  amendment,  the  Water  Quality  Act  of  1970, extended
Federal activities into such  areas  as  pollution  by  oil,
hazardous   substances,   sewage   from  vessels,  and  mine
drainage.

Originally,   pollution   control   activities   were    the
responsibility  of the U.S. Public Health Service.  In 1961,
the Federal Water Pollution Control  Administration  (FWPCA)
was  created  in  the  Department  of  Health, Education and
Welfare, and in 1966,  the  FWPCA  was  transferred  to  the
Department  of  the Interior.  The name was changed in early
1970 to the Federal  Water  Quality  Administration  and  in
December 1970, the Environmental Protection Agency (EPA)  was
created  by Executive Order as an independent agency outside
the Department of the Interior.  Executive  Order  11574   on
December 23, 1970, established the Permit Program, requiring
all  industries  to  obtain  permits for discharge of wastes
into  navigable  waters  or  their  tributaries  under   the
provisions  of  the  1899 River and Harbor Act (Refuse Act).
The permit program  immediately  became  involved  in  legal
problems  resulting  in  a  court  ruling  that  effectively
stopped issuance of a significant number of permits.   It did
result in the filing with EPA, through the U.S.  Army  Corps
of Engineers, of applications for permits which,  represent a

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complete  inventory  of  industrial  waste  discharges.  The
granting of a permit under the Refuse Act was  dependent  on
the  discharge  being  able? to meet applicable water quality
standards.   Although  EPA  could  not  specify  methods  of
treatment,   they  could  require  minimum  effluent  levels
necessary to meet water quality standards.

The Federal Water Pollution Control Act Amendments  of  1972
(the  "Act")  made  a  number  of fundamental changes in the
approach  to  achieving  clean  water.   One  of  the   most
significant  changes  was  from  a reliance on water quality
related  effluent  limitations  to  a  direct   control   of
effluents  through  the  establishment  of  technology-based
effluent guidelines  to  form  an  additional  basis,  as  a
minimum,  for  issuance  of  discharge  permits.  The permit
program under the 1899 Refuse  Act  was  plciced  under  full
control  of  EPA,  with  much  of  the  responsibility to be
delegated to the States.

PURPOSE AND AUTHORITY

Under  the  Act,  the  Environmental  Protection  Agency  is
charged  with establishing pretreatment standards to protect
the operation  of  publicly-owned  treatment  works  and  to
prevent  discharge  of  pollutants  which  pass through such
works inadequately treated.

As  part  of  this  Act,  Section  307(b)   states  that  the
Administrator    shall    "publish    proposed   regulations
establishing  pretreatment  standards  for  introduction  of
pollutants  into  treatment works (as defined in Section 212
of this Act) which are publicly owned for  those  pollutants
which  are  determined not to be susceptible to treatment by
such treatment works  or  which  would  interfere  with  the
operation  of  such treatment works.  Pretreatment standards
under this section shall specify a time for  compliance  not
to exceed three years from the date of promulgation."

This  report  is  prepared  for  the  purpose  of developing
pretreatment standards for existing  sources.   Pretreatment
standards  for  new sources have been promulgated October of
1974, (together with the effluent limitations guidelines for
the Steam Electric Power Generating Point Source Category).

SCOPE OF WORK AND TECHNICAL APPROACH

The pretreatment standards proposed herein were developed in
the following manner.  A comprehensive survey was  conducted
of  over  1200  steam  electric  generating  stations in the
United States.  The stations were screened  in  two  stages:
(1)  the  entire  population  was screened and cross-matched
using  available  references  and   (2)  230  stations   were
                            10

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contacted  by  telephone.  The list of plants that discharge
to a POTW was first studied for the purpose  of  determining
whether  separate  standards would be required for different
divisions within the list.   The  analysis  was  based  upon
fuels  used,  size  production  process employed, wastewater
pretreatment at plant sites, and  other  factors.   The  raw
waste   characteristics   for  each  subcategory  were  then
identified.  This included an analyses of  (1) the source and
volume of  water  used  in  the  process  employed  (2)  the
constituents   (including   thermal)   of   all  wastewaters
including constituents which  result  in  taste,  odor,  and
color  in  water,  (3)  the effect of the constituent on the
operation of the POTW and (4) the adequacy of  the  POTW  in
treatment of such constituents.  Wastewaters which should be
subject to pretreatment standards were identified.

The  full  range  of  control  and pretreatment technologies
existing  within  each  subcategory  was  identified.    This
included   identification   of  each  distinct  control  and
pretreatment technology, including both in-plant and end-of-
process technologies, which are existent or capable of being
designed  for  each   division.    It   also   included   an
identification   of  the  amount  of  constituents  and  the
chemical,  physical,  and  biological   characteristics   of
pollutants.   Effluent levels resulting from the application
of each of the pretreatment and  control  technologies  were
also identified.  The problems, limitations, and reliability
of  each  pretreatment  and  control  technology  were  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,
and  solid  waste,  were  also   identified.    The   energy
requirements   of   each   of   the  control  and  treatment
technologies were identified as well  as  the  cost  of  the
application of such technologies.

The  information,  as  outlined above, was then evaluated in
order to determine what levels of technology  are  available
for  effluent  reduction.  In identifying such technologies,
various factors were then considered.   These  included  the
total   cost  of  application  of  technology,  the  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.

Data  for  identification  and analyses were obtained from a
number of sources.   These  sources  included  EPA  research
information;  EPA, state, and local environmental personnel;
trade   associations;   published   literature;    qualified
technical  consultation;  historical information on effluent
                            11

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quality  and  quantity;   and   on-site   visits   including
analytical  programs and interviews at steam electric plants
throughout the United States which were known to have  above
average  waste pretreatment facilities.  All references used
in developing the pretreatm€:nt standards reported herein are
listed in Section XI of this; document.

Twenty-three operating plants were visited  and  eight  were
sampled.   Composite samples over a sixteen hour period were
obtained from these  eight  plants  and  were  analyzed  for
parameters mentioned in Section V.  Information was obtained
from  as  many  as  fifteen  (15) plants for each waste-type
division.   Both  in-process  and  end-of-pipe   data   were
obtained   as  a  basis  for  determining  "citer  use  rates
capabilities and effluent loads.   Permit  application  data
was  of  value for the purposes of this study when such data
covered  outfalls  serving   only   steam   electric   power
operations.

Cost  information was obtained directly from industry during
plant visits, from engineering firms,  equipment  suppliers,
and  from  the  literature.   These  costs have been used to
develop general capital, operating, and total costs for each
pretreatment and control method.  This generalized cost data
and specific information obtained from plant visits was used
to estimate cost effectiveness in Section VIII and elsewhere
in this report.

Certain plants were selected for in-depth analysis from  the
total population of those visited.  These plants were plants
discharging  representative  waste  types or employing above
average   treatment   technology   or   having   substantial
quantities of historic effluent data.

The following selection criteria were developed and used for
selection of plants visited and sampled.

    1.   Representative plant with  respect  to  fuel  type,
         size, geographical location and other factors.

    2.   Plants that discharge types or quantities of  waste
         representative of those delineated in Section IV.

         Plants that have treatment,

GENERAL DESCRIPTION OF THE INDUSTRY

The  Steam Electric Power Industry is made up of 1273 plants
throughout the contiguous United States.  Of these plants an
estimated 7.7 percent or 98 plants discharge wastewaters  to
publicly-owned  treatment  works and are thus covered by the
                            12

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scope of this document.  In this study 49 plants discharging
to POTW were contacted.

Statistics for this section were estimated based on a  truly
random  sampling of steam electric power plants contained in
the "Environmental Assessment of Alternative Thermal Control
Strategies for the Electric Power Industry" by  Michelle  M.
Zarubica  of  the  Office  of Planning and Evaluation of the
Environmental Protection Agency  (18).

Steam Electric plants discharging to the POTW tended  to  be
smaller  on  the  average than plants discharging to surface
water.  These plants averaged  about  150  MW  for  a  total
capacity  of  14,500  MW  which  compares  with  an  average
capacity and total generating capacity of about 400  MW  and
506,700  MW  for  the  entire Steam Electric Industry.  (See
Tables III-l and III-2).  Of these plants, an  estimated  72
percent  are  publicly-owned  and  28  percent  are investor
owned.

Most of the Steam Electric plants that discharge to POTW (68
percent) use gas as their  principal  fuel  compared  to  31
percent  for  the entire industry (Figures III-l and III-2).
Conversion of some plants from gas to oil is expected due to
shortage of natural gas.

Plants which discharge wastewaters  to  POTW  tend  to  have
units  older  than plants which discharge to surface waters.
Tables III-l and III-2 show that 29 percent  of  the  plants
which discharge to POTW were built since 1960 as compared to
38  percent  for  the entire population.  Also, plants built
since 1960 represent 48 percent of the  generating  capacity
of plants discharging to POTW compared to 78 percent for the
entire Steam Electric Industry.  (See Figures III-3 and III-
4).

Approximately  24  percent  of  all electrical generation is
nuclear powered but no plants of this type were observed  to
discharge  to  the  POTW.   Nonetheless,  nuclear plants are
included  in  this  document,  since  their  chemical  waste
discharges are similar in nature to those discharged by non-
nuclear facilities (14) .

Steam Electric plants discharging to POTW are located in all
regions  of  the  country  with somewhat higher than average
concentrations in the Midwest and in California.

Process Description

The "production" of electrical  energy  involves  utiliation
and  conversion  of chemical or nuclear energy.  Present day
methods of utilizing energy of fossil fuels are based  on  a
                            13

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      Table III-l.  TOTAL. STEAM ELECTRIC PLANTS IN THE
                  CONTIGUOUS UNITED STATES
Total Number of Plants   = 1273
Total Number of Units    = 3011
Total Number of Megawatts^ 506,654
Average Station Size     = 398
Percentage of Plants Confirmed as  Discharging
  to Municipal  Sewers - by Number     = 7.7%
                        by Megawatts = 2.9%
    Principal         Percentage by       Percentage by
    Unit Fuel         	Number            Megawatts

     Gas                  31.0
     Oil                  14.6
     Coal                  49.3
     Nuclear               5.1
                         100.0
                     Percentage by       Percentage by
  Unit Built In      	Number            Megawatts

     1970's              17.6                57.6
     1960's              20.3                20.1
     1950's              36.1                17.6
     1940's              16.0                 3.7
     1930's               6.5                 0.8
     1920's               2.7                 0.1
     1910's               0.8                 0.1
                       14

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     Table  II1-2.  STEAM  ELECTRIC PLANTS DISCHARGING TO
      MUNICIPAL SEWERS  IN THE CONTIGUOUS UNITED STATES


Total Number of Plants    = 98
Total Number of Units     = 277
Total Number of Megawatts - 14504
Average Station Size      = 148
    Principal
    Unit Fuel

     Gas
     Oil
     Coal
     Nuclear
Percentage by
    Number

     67.7
     17.7
     14.7
      0.0
Percentage by
  Megawatts

     44.1
     54.0
      1.9
      0.0
                         100.0
                        100.0
  Unit Built In

     1970's
     1960's
     1950's
     1940's
     1930's
     1920's
     1910's
Percentage by
    Number
      5.
     23.
     35.3
     23.5
      5.9
      5.9
      0.0
    100.0
Percentage by
  Megawatts

      4.3
     43.2
     47.0
      5.2
      0.2
      0.1
      0.0
    100.0
                       15

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  TOO
   90
   80
   70
                 OVERALL    PLANTS
               POPULATION   DISCHARGING
                            TO  POTW'S
OO
o

UJ
CJ
o:
   60
   50
   40 J
   30
    20
    10
              GAS
            FIGURE III-l
     OIL


PRINCIPAL FUEL
                                              COAL
                                NUCLEAR
 Principal Fuel Use by Number
   16

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  100
   90
   80
•=C
CS
o

LlJ
cs
Cd
UJ
a.
   70
   60
   50
   40
   30
   20
   10 . .
                  OVERALL     PLANTS
                 POPULATION  DISCHARGING
                             TO POTW'S
              GAS
     OIL

PRINCIPAL FUEL
COAL
NUCLEAR
         FIGURE  III-2.   Principal  Fuel  Use by Megawatts

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  100 .
   90
   80
   70
   OVERALL DISCHARGING
POPULATION TO POTW'S
CO
C_3
o:
   60
   50
   40
   30
   20
   10
        1910
1920   1930    1940,    1950   1960


      YEAR PLANT BUILT
             1970
           FIGURE III-3.  Year of Construction  by Number
                             18

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  100 .
   90
   80
5  70
3

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combustion  process, followed by steam generation to convert
the heat first into mechanical energy and  then  to  convert
the  mechanical  energy into electrical energy.  The maximum
theoretical efficiency that can be  obtained  in  converting
heat  to  work  is  limited by the temperatures at which the
heat can be absorbed by  the  steam  and  discarded  to  the
environment.   The  upper  temperature  is  limited  by  the
temperature of the fuel bed and the structural strength  and
other  aspects  of  the  boiler.   The  lower temperature is
ideally the ambient temperature of the environment, although
for practical purposes the reject temperature must be set by
design significantly above the highest  anticipated  ambient
temperature.   Within  these  temperatures, efficiencies are
limited to about t»0 percent regardless of any improvement to
the  machines  employed.   For  any  steam  electric   power
generation scheme, therefore, a minimum of 60 percent of the
energy  contained  in  the  fuel  must  be  rejected  to the
environment as waste heat
Fossil- fueled steam electric power plants  produce  electric
energy  in a four-stage process, shown in Figure III-5.  The
first operation consists of the burning of  the  fuel  in  a
boiler and the conversion of water into steam by the heat of
combustion.  The second operation consists of the conversion
of the high- temperature, high-pressure steam into mechanical
energy in a steam turbine.  The steam leaving the turbine is
condensed to water, transferring heat to the cooling medium,
which  is  normally  water.   The turbine output is conveyed
mechanically to a generator, which converts  the  mechanical
energy  into  electrical  energy.   The  condensed  steam is
reintroduced into the boiler to complete the cycle.

The theoretical water-steam cycle employed in steam electric
power plants is known as the Rankine cycle.   Actual  cycles
in power plants only approach the performance of the Rankine
cycle  because  of practical considerations.  Thus, the heat
absorption does not occur at  a  constant  temperature,  but
consists  of  heating  of  the  liquid to the; boiling point,
converting the liquid to  vapor  and  superheating   (heating
above  the  saturation  equilibrium  temperature)  the steam.
Superheating is necessary to prevent excess condensation  in
the   turbines   and   results  in  an  increase  in  cycyle
efficienty.  Reheating, the raising of the; t€>mperature above
saturation of the  partially  expanded  steam,  is  used  to
obtain  improvements  in  efficiency  and  again  to prevent
excess  condensation.  Preheating  of  coriderisate  to   near
temperatures with waste heat, is also used for this purpose.
Condensers  cannot  be  designed to operate ait theoretically
optimum values because it would  require  infinitely  larger
equipment.   All  of  these  divergences  from  the  optimum
theoretical conditions cause a decrease in efficiency and an
increase  in  the  amount  of  heat  rejected  per  unit  of
                            20

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                                       STEAM
TV)
      FUEL INLET
                       BOILER
               ASH  OUTLET
                                                          TURBINE
                                   BOILER FEED WATER
                                                CONDENSER
GENERATOR
J
ELECTRIC

POWER
                                                                                   COOLING WATER IN
       COOLING WATER OUT
                                                FIGURE   III-5
                                            Process hlow  Diagram
                                        Steam  Electric  Power  Industry

-------
production.  As a result, only a few of the larger and newer
plants  approach  even  the  efficiencies possible under the
ideal Rankine cycle.   Also,  as  a  result  of  second  law
limitations, modifications of the steam cycle of an existing
plant  are not likely to result in significant reductions in
heat rejection.

Publicly-Owned Treatment Works (POTW)

The POTW process is broken down into three  basic  treatment
methods;   primary,   secondary,   and   tertiary.    Primary
treatment consists  of  the  removal  of  coarse  materials,
settleable  solids,  oil  and grease,  floating material, and
the reduction of biological oxygen demand.   Most POTW employ
secondary treatment which  converts  soluble  and  colloidal
organic  material  into  settleable flocculant material that
can be removed by sedimentation.  Secondary treatment  which
consists  of  biological treatment, is often enhanced by the
addition of chemicals such  as  iron,   aluminum  salts,  and
polymeric   flocculants.   The  use  of  tertiary  treatment
processes are still uncommon  and  include  the  removal  of
chemical  constituents not affected by primary and secondary
treatment.   Tertiary  treatment  is  intended   to   remove
chemicals  which  promote  algae growth and unwanted aquatic
vegetation.  A more detailed description of the POTW process
can be found in Section V.

The POTW receiving wastewaters from  steam  electric  plants
vary  in size and treatment process employed.  Plant size is
determined by human population and industrial waste load  of
the  area served.  Those contacted in this study ranged from
200,000 gpd to 350,000,000 gpd in size.   Treatment  methods
are  determined  by flow, waste load pollutant constituents,
economics, energy and removal requirements, and  plant  age.
There  are  a large number of wastewater treatment processes
in  use  whose  application   is   related   both   to   the
characteristics  of  the  waste  and the degree of treatment
required.  These processes are shown in Figure III-6.
                            22

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ro
00
PRIMARY
TREATMENT
SECONDARY
TREATMENT-
TERTIARY
TREATMENT
               SCREENING AND
                6»n REMOVAL
                         i
              EOUALIZATIOH MD
                 STOSACL
              OR SEPARATION  L
                                   CHEMICAL    1
                                  A001UON A«0   I
                                  COAGULATION   f
                                   FlOTATIOd
                                  SEDIMENTATION















-,



H



-



-

ACTUATED
SLUDGE



LAGOONS



FILTER



AERATED
LAGOON

j



-



H



~















^ COAGULATION
AND
SEDIMENTATION
1


FILTRATION
|


H CARBON
ADSORPTION
i


i ION

-



L



_


















                                                      STA8LIZATIDN
                                                         BASIN
                                                     SEDIMENTATION
                                                                                                                                      RECEIVING
                                                                                                                                       WATERS
'  CONTROLLED OR
'  TRAXSPOPTtO
•   DISCHARGE
                                         FIGURE   III-6.    Uastewater  Treatment   Sequence

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                         SECTION IV

                  INDUSTRY CATEGORIZATION
INTRODUCTION

An evaluation of  steam  electric  power  industry  stations
discharging  chemical  wastes  to  publicly-owned  treatment
works    (POTW)   was   necessary   to   determine    whether
categorization and subcategorization would be helpful in the
preparation  of  effluent  pretreatment  standards  for this
industry.  Subcategorization  was  based  on  distinguishing
factors within groups of plants.

This  method  of  subcategorization  was  also  used  and is
discussed  in  detail  in  the  "Development  Document   for
Effluent  Limitation  Guidelines  and New Source Performance
Standards for the Steam Electric Power Generating  Category"
October 1974  (18) .

Standards  will be established for each waste source and can
then be applied and utilized in the  manner  of  a  building
block  concept.   In  the case of combined waste streams the
appropriate  standards  will  be   combined   and   weighted
proportional  to  stream  flow.   The  eight waste types are
presented in Table IV-1.

The following were considered for  industry  categorization:
ager  size,  fuel,  geography,  mode of operation, raw water
quality, volume of water used, and pretreatment technology.

INDUSTRY CATEGORIZATION

The wastes of this industry have been divided  according  to
the individual waste source.  Marked differences in type and
level   of  pollutants  were  observed  in  facilities  with
different  fuel  type,  boiler  and  pretreatment  practice.
These  differences  were considered together with age, size,
geography, mode of operation, and feed water hardness in the
development of possible subcategorization.

FACTORS CONSIDERED

Age

Power plants discharging to the POTW tend to be  older  than
surface  water  discharging plants.  In steam electric power
plants, individual generation units are often  installed  at
different times over a number of years.  Newer units tend to
be  thermally  more  efficient then older units and use less
fuel per killowatt hour of electricity produced.  Because of
                            25

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fuel economics newer units generally tend  to  be  used  for
base  load  production  while  other  units  are employed as
peaking and cyclic  units.  Increased  fuel  efficiency  may
reduce  wastewater  loads  such  as ash transport water, wet
scrubber water, etc.

Size

Although the size of steam electric power plants discharging
to POTW varies significantly, the basic process is common to
all facilities.  Plant size was found to have little  affect
on  quantity  of  treated  effluent.  Plants  discharging to
sanitary  sewers  tend  to  be  smaller  than  power  plants
discharging to surface water.

Fuel

Plants  discharging  to  POTW were identified as burning all
three major fossil fuels, coal, oil, and gas. In contrast to
the entire population of steam electric plants in  the  U.S.
the  majority  of  plants contacted in this study use gas as
fuel.   Fuel-related wastes such as  ash  control  transport
water  and  coal pile drainage, can contribute to wastewater
discharge. The presence of sulfur in the  fuel  may  require
scrubbers.  Therefore,  the  affect  of  different  fuels on
certain   processes   and   effluents    is    useful    for
subcategorization.

Geography

Usually,  steam  power plants that discharge to the POTW are
located near or within municipal boundaries.   Most  of  the
plants  contacted were, in fact, situated in downtown areas.
Plants discharging to the sewers were located in nearly  all
geographical regions of the United States.  It is noted that
recent  trends  toward larger power generating stations, and
the institution of mine-mouth coal fed plants, have resulted
in increased rural plant construction and a  reduced  number
of municipally-located plants.
                            26

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                        TABLE IV-1
I.       Condenser Cooling System
         A.   Once-Through
         B.   Recirculating

II.      Boiler Water Pretreatment
         A.   Clarification
         B.   Softening
         C.   Ion Exchange
         D.   Evaporator
         E.   Filtration
         F,   Other Treatment

III.          Boiler or PWR Steam Generator
         A.   Slowdown

IV.      Maintenance Cleaning
         A.   Boiler or PWR Steam Generator Tubes
         B.   Boiler Fireside
         C.   Air Preheater
         D.   Misc. Small Equipment
         E.   Stack
         F.   Cooling Tower Basin

V.       Ash Handling
         A.   Oil-Fired Plants
              1.   fly ash
              2.   bottom ash
         B.   Coal-Fired Plants
              1.   fly ash
              2.   bottom ash

VI.      Drainage
         A.   Coal Pile
         B.   Contaminated Floor and Yard Drains

VII.          Air Pollution Control Devices
         A.   SO2 Removal

VIII.    Miscellaneous Waste Streams
         A.   Sanitary Wastes
         B.   Plant Laboratory and Sampling Systems
         C.   Intake Screen Backwash
         D.   Closed Cooling Water Systems
                            27

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Mode of Operation

Many  of  the  plants  discharging into POTW are peaking and
cyclic stations.  The type of pollutants generated from base
load, peaking, and  cycling  facilities  are  similar.   The
quantity  of  effluent  per  unit  of  energy  generated  is
expected to be greated for peaking facilitites.  Some of the
plants  generate  steam  for   sell   and   for   electrical
production.

Raw Water Quality

Hardness  would  indeed  affect  operation by increasing the
frequency of regeneration of the deioriizer or recharging the
softener. The harder the raw water the more  frequently  the
deionizer  anion  and cation must be regenerated and the hot
lime and zeolite units have to be  recharged.   For  cooling
tower   intake,   poor   water   quality  would  reduce  the
concentration factor and thereby increase discharge flow and
pollutant loading.
Volume of Water Used

Water use varies greatly even among plants of  approximately
the  same  size.   For  cooling  water,  flow  is  primarily
effected  by  the  efficiency  of  the  boiler  system   and
temperature  across the condenser.  For chemical wastewater,
factors such as a good maintenance procedure and  raw  water
quality  are  sometimes  more important than the capacity of
the plant.  For water short areas, the  cost  of  the  water
supply  encourages  water  conservation.   Volume of certain
water streams, such  as  boiler  blowdown,  can  be  greatly
affected by the amount of steam produced for seridout.

Pretreatment Technology

Of  the  plants discharging into POTW, many plants discharge
all of their wastewater effluent to municipal sewer systems;
others discharge only a portion. The extent of  pretreatment
varies  widely  from  no  pretreatment  to integrated plants
using systems such  as  equalization,  neutralization,  etc.
None   of   the   facilities   visited   or  contacted  have
pretreatment facility equivalent to that required to achieve
BPCTCA.
                            28

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                         SECTION V

            WATER USE AND WASTE CHARACTERIZATION
INTRODUCTION

Specific water uses and the waterborne  wastes  involved  in
steam   electric   plants  discharging  into  publicly-owned
treatment works (POTW) are described in this section,  along
with  other  process  waste  materials.   Process waters are
characterized as raw waste  loads  from  specific  processes
associated  with  the  production of electricity.  These are
generallly expressed as grams per  megawatt  hour  (MWH)  of
electricity  generated.   Water  uses  are given in terms of
liters per MWH, or as liters per day  and  waterborne  waste
loads  in  mg/liter  or  grains  per MWH.  Based on available
data, it does not appear that  the  quantity  of  pollutants
discharged    is   directly   proportional   to   electrical
generation.  Factors such as raw water quality,  maintenance
procedures,  etc., can be just as influential in determining
chemical  loadings  as  electrical  generation.   The  waste
treatments   used   by  both  power  plants  and  POTWs  are
described,  and  amounts  and  types  of  waterborne   waste
effluents after treatment are characterized.

PRINCIPLES OF OPERATION OF STEAM ELECTRIC POWER PLANT

In a steam electric power plant, thermal energy, produced by
rapid  chemical  combustjon  or nuclear fission reaction, is
first tranformed into hi--,h pressure, high temperature steam,
and then to mechanical energy through expansion of the steam
in a turbine.  The process can be divided into four  stages.
The  first  operation  consists  of  fuel  combustion in the
boiler furnace to produce high pressure, superheated  steam.
The  steam  is  conveyed to a turbine where it is allowed to
gradually expand and cool in the various turbine  stages  to
convert  the  thermal  energy  into  electrical  energy  via
mechanical energy.  In the third operation the steam exiting
from the final stage of the turbine is condensed  to  water,
transferring the heat to a cooling medium, which is normally
water.   Finally  the condensed steam is reintroduced into a
boiler by a pump to complete the cycle.

The  power  cycle  components  can  be  divided  into  three
principal units:

    o    steam boiler
    o    steam turbine
    o    condenser
                            29

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Each of the cycle components provides an energy transfer and
transformation function necessary to convert the heat energy
into  useful  work.  The following are descriptions of these
three units. A more extensive discussion on  the  principles
of  design  and operation of steam electric power plants can
be found elsewhere (14,16).

Boilers

All boilers use the same basic design,  that  is,  they  are
large  multi-tube  heat  exchangers surrounded by a furnace.
The feedwater  circulates  within  the  tubes  where  it  is
heated,  vaporized, and superheated producing steam to drive
the  steam  turbine  generators.   Many   different   boiler
arrangements  are  used.  Oil and gas-fired boilers somewhat
are simpler than coal-fired boilers because  in  most  cases
liquid  and  gaseous  fuels  do  not  require the conveyers,
pulverizers, and ash collection equipment necessary in coal-
fired boilers.  The boiler structure may be  either  exposed
or  enclosed  depending  on local weather conditions, and is
usually very large to accommodate  the  large  tube  surface
areas   required.    Air  heat€;rs,  economizers,  and  other
sections of the boiler  are  us:ed  to  extract  the  maximum
amount  of  heat  from  the combustion gases before they are
discharged to the environment.  This serves to increase  the
boilers  efficiency: the ratio of heat converted to steam to
the heat input value of the  burning  fuels.   Modern  power
boilers  are  able to achieve 85 to 90 percent efficiencies;
the remaining 10 to 15 percent of the input  heat  value  is
discharged  to the environment with the exhaust gases.  This
loss is referred to as the "stack loss."  Figure V-l shows a
typical boiler for a coal fired furnace.

Steam Turbine

The steam turbine consists of alternate rows of nozzles  and
blades  on  wheels.   Each row of nozzles and its associated
row of blades is called  a  turbine  stage.   As  the  steam
expands  through the nozzles, the pressure decreases and the
velocity and specific volume increase.  When the steam comes
in contact with the blades a part of the  momentum   (kinetic
energy) is transferred to the blades.  The turbine shaft and
generator are caused to rotate and electricity is produced.

There  are  many  different  types  of  turbines and turbine
arrangements in use.   Most  of  the  turbines  are  of  the
condensing  type,  discharging the steam from the last stage
at below atmospheric pressure.  The efficiency of a  turbine
is highly sensitive to the exhaust pressure  (back pressure).
Turbines  designed  for  once-through  cooling  systems  are
generally  operated  at  lower  back  pressures  than   that
designed for closed cooling systems.
                            30

-------
                                                         Oust
                                                         collector
                   Primary
                   superheater
                                                         Economizer
                                                   -\  -\  Air heater


                                                         Cinder
                                                         reinjsction

                                                         forced
                                                         aroftfon
                                                         (in back)
                                                         Induced
                                                        . draft fan
Figure  V-].  Typical   Boiler for  Coal-Fired  Furnaces
                             31

-------
In  most  turbine arrangements a portion of the steam leaves
the casing before the final stage.  This type of turbine  is
referred  to  as extraction turbine.  The extracted steam is
used for feedwater heating purposes.  In  some  turbines,  a
portion  of the steam is extracted from intermediate stages,
reheated in the boiler,  and  returned  to  the  turbine  or
another turbine as a means of improving overall efficiency.

Steam Condensation

Steam  leaving  the  final stage of the turbine is condensed
into water in the condenser.  This  is  essentially  a  very
large  shell  and  tube heat exchanger designed to withstand
the high vacuums associated with modern steam turbine  power
cycles.   Heat  is  transferred from the exhaust steam to an
external cooling water system which may draw  water  from  a
surface  or  underground  source, or from the cooling tower.
There are two types of condensers; the single-pass  and  the
two-pass  condensers.   If  all  the water flows through the
condenser tubes in one direction, it is call  a  single-pass
condenser.   If  the  water  passes  through one half of the
tubes in one direction and the other half  in  the  opposite
direction,  it  is  referred  to as a two-pass condenser.  A
single-pass condenser usually requires a larger water supply
than a two-pass condenser and generally results in  a  lower
temperature rise in the cooling water.  Many condensers have
divided  water boxes so that half the condenser can be taken
out of service for cleaning while the unit is  kept  running
under  reduced  loads.   Condensers are periodically cleaned
mechanically  as  part  of  regular  scheduled   maintenance
procedures.    Some   plants   employ   continuous   on-line
mechanical cleaning.  Figure V-2 shows a typical single-pass
condenser.

WATER USE AND WASTE CHARACTERIZATION BY CATEGORY

The results obtained on power  plant  wastes  from  visiting
twenty-three   plants  and  sampling  eight  do  not  differ
substantially  from  those  reported  in  the   "Development
Document  for Effluent Limitations Guidelines and New Source
Performance  Standards  for   the   Steam   Electric   Power
Generating Point Source Category"  (14).

The  majority of the water used in steam electric generating
plants is for condenser cooling water.  Lesser  amounts  are
used   for  boiler  makeup  water,  bearing  cooling  water,
equipment  cleaning,  and  other   miscellaneous   purposes.
Figure  V-3   shows a typical Steam Electric process diagram
with wastewater sources.

Waste discharges can be  classified  under  two  categories:
continuous  discharges, and intermittent discharges.  Wastes
                            32

-------
co
co
    1
         /I
   OUT



 (HEATED)
                                STEAM FROM TURBINE EXHAUST

                                   0
CONDENSATE
                                               TO PUMP
                 \
0 (
) 6
ft
0
                           COOLING WATER IN

                                (COLD)
                               FIGURE V-2. Single-pass Condenser

-------
are produced on a continuous basis from  the  following  (if
applicable):  cooling  water  systems, ash handling systems,
wet-scrubber  air  pollution  control  systems,  and  boiler
blowdowns  (some of the streams can be intermittant).  Waste
discharges  are  produced  intermittently  by  boiler  water
treatment  operations  such  as  ion  exchange,  filtration,
clarification, and evaporation.  Intermittent discharges are
also  produced  during  miscellaneous   equipment   cleaning
operations and from sanitary and laboratory wastes.

The following discussion is a categorization and description
of water uses and waste discharges within typical generating
plants.   Some  of  the  following  has been summarized from
Reference 11, which contains a more detailed  discussion  of
water  use  and  waste characterization.  Data obtained from
the site visits and sampling program are discussed below.

CONDENSER COOLING WATER

The condenser cooling systems can be classified as (1)  once-
through, or  (2) recirculating.  Of the  twenty-three  plants
surveyed,    seven    use    once-through,    thirteen   use
recirculating, one plant is a hybrid, and two plants operate
only at peak periods and are therefore not included in  this
section.

Once-Through Systems

In  areas  where  large  amounts of water are available from
natural sources, the simplest method of condensing steam  is
to  withdraw  water  from  the  source,  pass  it  through a
condenser, and discharge it back into the same source  at  a
higher   temperature.    Biocides   such   as   chlorine  or
hypochlorites are usually added to systems of this  type  to
minimize  biological  growth  within  the condenser.   Of the
plants  surveyed  in  this  study,  none  were  observed  to
discharge once-through cooling systems to POTW.

Recirculating Systems

Condenser  cooling  water  can  be  recirculated  within the
plant.  This is  accomplished  by  providing  some  sort  of
artificial  cooling  device,  such  as  a  pond or a cooling
tower, to cool the cooling water by evaporating a portion of
it before recirculating it back to the condenser.  Ponds are
used  only  where  large  areas  of  inexpensive  land   are
available,  since a large plant may require over 1,000 acres
of pond surface.  Cooling towers may be either of the wet or
dry types, and are used where sufficient land for  ponds  is
unavailable  or  too  expensive.   Since all cooling devices
(except dry cooling towers, which  are  rare)  transfer  the
process   waste  heat  to  the  atmosphere  by  evaporation.

-------
CO
en








RAW


i



i
,
i
i




- WASTE- • 	
W WATER

CHEMICALS

1

WATER
'• TREATMENT 	
i



WASTE- *
WATER






CHEMICALS
— i *
BOILER TUBE
CLEANING, FIRE-
SIDE & AIR'
PREHEATER
WASHINGS






FUEL—*
COMB'N AIR--«
BOTTOf
ASH








'











1








HATER FOR '" ""f ™
PERIODIC CLEANING !
t
1
. FLY ASH •VWNkXXXX CHEMICALS
COLLECTION
	 	 	 	 _ __^ AND/OR S02
STEAM f SCRUBBING-
iitfln DEVICE
f l^^l
	 L FLUE 1 [URBINE 1 .U'A-TU'ATCr •
I WES . I GENERATOR ! J ,
f — --^^^__^^ i
STEAM -1 ; CHEMICALS
GENERATING * CK
BOILER S" X * +'. • ONCE THROUGH
/ \ " COOLING WATFR
1 	 ^ 	 1- f rrvmr-,-rc V. '• RECIRCULAT ING COOLING WATER
SLOWDOWN ]• I CONDE.NSER * -' ' 	 	 ' ' "" " 	 ' "
\ /*1 * i 	 ^
\. j/ , , \ COOLING TOWER /
DISCHARGE TO ^ \
WATER BODY * \ U^CHEMICALS
CONDENSATE WATER, \ f,*
* MAKEUP WATER 	 ^V 'f
1* ' ••
+
                                                                                                  BLOWDOWN
                                                   «NS\V\\\CHEHICALS
                                                         WATER
                                                                          SANITARY WASTES
                                                                          LABORATORY & SAMPLING
                                                                          WASTES, INTAKE SCREEN
                                                                          BACKWASH, CLOSED  COOLING
                                                                          WATER SYSTEMS, CONSTRUC-
                                                                          TION ACTIVITY
                                                                                                    LEGEND:
                                                                                                            LIQUID FLOW
                                                                                                        	 GAS & STEAM FLOW
                                                                                                    \\XOl\\.
                                                                                                    \\s\\v\
CHEMICALS

OPTIONAL  FLOW

WASTEWATER
             FIGURE   V-3 -  Fossil-Fueled  Steam-Electric Power  Plant  -  Typical  Flow Diagram

-------
Additional water must be added to the system to make up  for
these losses due to evaporation, drift and blowdown.

Various chemicals are added to recirculating cooling systems
to  prevent  biological  growth  in  cooling  towers  and to
control scale  accumulation  and  corrosion  in  condensers.
These  include biocides such as chlorine, hypochlorites, and
organic chromates;  corrosion  inhibitors  such  as  organic
phosphates, sodium phosphate, chromates, and zinc salts; and
fungicides.

Wastes  that  may be discharged to a POTW from recirculating
cooling  systems  originate  from  cooling  tower  blowdown.
Blowdown  is  the  discharge  from  the  cooling  tower of a
portion of water  either  constantly  or  intermittently  to
prevent  the  concentration  buildup  of salts that may form
scale deposits within the  condenser.   This  blowdown  will
contain   calcium,   magnesium,   and   sodium   cations  in
combination  with  carbonate,  bicarbonate,   sulfate,   and
chloride  anions.   Additionally,  various  amounts  of  the
conditioning chemicals will be present.   Sulfuric  acid  is
also used in closed cycle cooling systems.

The  rate  of  blowdown  can  be estimated by the use of the
following equation: (Ref. 1)

         B = Ev - D(01)
                 C-l

    where:   B is the blowdown rate; Ev is evaporation
             rate; D is drift losses; and C is the
             cycles of concentration defined as the
             ratio of the concentration of a critical
             chemical species in the blowdown to that
             in the makeup water.

The evaporation rate (Ev) from cooling towers averages about
1.5 percent of the cooling water flow for every 10°C rise in
cooling water temperature as the water  passes  through  the
condensers.   The  drift  rate  (D)  for new cooling towers is
about 0.005 percent of the cooling water flow for mechanical
draft towers, and about  0.002  percent  for  natural  draft
towers  (Reference  1).   Cycles  of concentration  (C) is an
expression of the buildup of any constitutent in the cooling
water system from its original value in  the  makeup  water.
In  practice,  C  is usually between 4 and 6.  For very high
quality makeup water, C may be as high as 15, and  for  very
saline water, C may be as low as 1.2-1.5.

Figure  V-4  shows  typical  once-through, and recirculating
cooling system flow diagrams.  Figures V-5 and V-6 show  two
types of wet cooling towers.
                            36

-------
Water Use

Once-Through  Systems.   Seven  of  the  twenty-three plants
surveyed use a once-through cooling  system  to  remove  the
waste  heat from the process.  The water usage in liters per
MWH at the plant studied is given below:
         Plant No.

           9369

           7420

           9163

           6387

           8356

           6421

           6294
Water Usage Liter/MWH

   9.33x104

   3.3x104.

   1.18x105

   3.68x105

   2.57x105

   2.24x105

   8.28x104
A similar range of  water  use  for  once-through  condenser
cooling  of  Ixl05_  to  3.5xl05_  liters per MWH was reported
elsewhere  (14).

The water use data were  plotted  against  power  generation
rate  to  determine  the  effect  of  that  function  on the
quantity of water used.  (See Appendix A) .  The  results  of
the   statistical   analysis  suggest  that,  based  on  the
available data, there is at best a poor correlation  between
water  use  for  once-through  cooling system and generation
rate for plants in this study.  Although the  overall  trend
suggests  that  the  water  use  may  decrease slightly with
increasing generation rate, this is not substantiated by the
statistical analysis of available data.  One explanation for
such phenomena is that cooling water pumps are in  on-or-off
modes.   For  a  facility  with  two  cooling  water  pumps,
production would have to be less than  half  of  the  design
capacity  before the cooling water flow would decrease.  For
some facilities, the pumps are always kept in  operation  to
lessen  pump maintenance.  Another explanation is the change
in temperature across the condenser between stations.

Recirculating Systems.  Thirteen of the 23  plants  surveyed
use a recirculating condenser cooling system to remove waste
heat  from  the  process.   Waste  heat  is removed from the
cooling water by means of evaporation and  blowdown.   Water
usage  in  liters  per  MWH  at  the plants studied is given
below:
                            37

-------
                  EXHAUST STEAM
                  FROM TURBINE
SURFACE
WATER  •
CONDENSER
  DISCHARGE TO
-^SURFACE WATER
                   CONDENSATE
      EXHAUST STEAM
      FROM TURBINE
               EVAPORATION
       CONDENSER
                                     COOLING
                                      TOWER
                                                  MAKEUP
                                                  WATER
       CONDENSATE
                   COOLING  WATER
     FIGURE  V-4 .   Once-Through  (top)  and
       Reelrculating  (bottom)  Cooling
               38   Systems

-------
 WATER IN.	fr
                                         SPRAY ELIMINATOR
       PUMP
   =[
                             6
AIR IN
                                              FILL
                                             AIR IN
FIGURE   V-5  .  Diagram of Wet Induced-Air Cooling  Tower
                    39

-------
HOT WATER
DISTRIBUTION
   DRIFT
   ELIMINATOR
       FILL	l^-^-c-— —
                                       AIR
                                      INLET
                             COLD WATER
                             BASIN
                  FIGURE  V-6
       Natural-Draft  Wet  Cooling  Tower
               (Counter-Flow)
                 40

-------
        Plant No.                 Water Usage Liters/MWH
          9600                    1.64x101*
          9650                    3.21x103
          9369                    1.80x101
          9371                    3.44x103
          8816                    2.14x102
          9585                    8.39x102
          8696                    5.6x10^
          8135                    1.41x104.
          8392                    1.76x104
          6293                    4.1x103
          7308                    1.8x103
          8875                    2.36x103
          8231                    2.53x103

The water usage data was plotted on log-log paper versus the
production rate to determine the effect of the plant size on
the quantity of water used.  (See Appendix A).  The  results
of  the  statistical  analysis  suggest  that,  based on the
available data, there is no correlation at all between water
use for recirculating condenser cooling and production rate.
Although the overall trend suggests that the water  use  may
increase   slightly   with  production  rate,   this  is  not
substantiated by the statistical analysis.   An  explanation
for such phenomena is that the blowdown from a recirculating
cooling   system  is  not  only  a  function  of  electrical
generation  capacity,  intake  water  quality,  geographical
location,  and  governmental  regulations, but also of other
factors.

Raw Waste Load

The raw wastes  from  the  recirculating  condenser  cooling
process include:

    o    Chemical additives to control growth organisms such
         as algae, fungi, and slimes;

    o    Chemical additives to inhibit corrosion; and

    o    Concentrations  of  solids,  metallic  salts,   and
         acidic and alkaline ions due to evaporative loss.

Initially,  all  of  these  wastes are waterborne, but some,
such as suspended solids and metallic salts settle and  must
be  removed  from  cooling tower basins periodically.  Also,
the settling of metallic  salts  cause  scale  formation  on
condenser tubes and may be removed occasionally usually with
an  acid  solution.   The  remainder  of  the raw wastes are
either   removed   from   the   wastewater   by    treatment
technologies, or are discharged to the sewer systems.
                            41

-------
Waterborne  wastes  are  shown in Table V-1  for plants 8392,
8231, 9650,  8135,  8696,  and  7308  from  which  data  was
obtained.  The waterborne raw waste values indicate that the
major   components  by  weight  in  recirculating  condenser
cooling streams are dissolved and total solids, and chemical
oxygen demand.

Wastewater Treatment

None of the  plants  using  once-through  condenser  cooling
systems   discharge   to   POTW.    Thirteen   plants  using
recirculating condenser cooling  systems  discharge  cooling
tower  blowdown  to  the  POTW.  None of the thirteen plants
discharging recirculating condenser cooling  wastewaters  to
POTW  employed  any  treatment  technologies.   Wastes  were
discharged directly to the POTW without treatment.

Effluent Waste Loads

Information  was  not  obtained  on   the   composition   of
recirculating condenser cooling wastes after treatment since
no  plants  performed  any treatment before discharge to the
POTW.   Waterborne  wastes  present  in  the   recirculating
condenser  cooling  discharge  to  the  POTW can be found in
Table V-1.

WATER TREATMENT

To compensate for steam losses through  leakage  and  boiler
blowdown,  additional  water  must  be  added to the boiler.
Particularly in high-pressure boilers, this water must be of
extremely  high  quality,   and   must   undergo   extensive
treatment.   If  the water is taken from a municipal supply,
treatment may consist  of  dual  media  filtration,  reverse
osmosis   filtration,  and  demineralization.   Older,  low-
pressure steam plants may treat boiler makeup  water  solely
with evaporators.  Some steam electric plants treat water by
clarification and softening followed by demineralization.  A
more  detailed  description  of  those treatment schemes and
their associated wastes follows.

Clarification is a process for  removing  suspended  solids.
After  water  is  lime treated, clarification can be used to
remove dissolved solids.  Chemical coagulants such as  alum,
ferrous  sulfate,  ferric  sulfate,  sodium  aluminate,  and
polyelectrolytes  are  added  to  the  water  to   aid   the
agglomeration   of   dissolved   impurities  by  adsorption,
absorption, and sedimentation.  The particles are allowed to
settle, and the clarified water is drawn off  and  filtered.
Softening  is  used  in  conjunction  with  clarification to
precipitate  calcium  and  magnesium.    Clarification   and
softening  wastes  consist  of  sludges  and  filter washes.

-------
                         Table  V-l .  RAW WASTE FLOWS  AND LOADINGS  CONDENSER-COOLING  SYSTEMS
Pl-'NT NO.
UAOTfWAUR SOURCE
FL04
PAR/SOFTER
LC1 j r
?ro-iide (Bromate)
COO
Ch rori un
r h ro- i jri*6
Copper
C/-jn»<)« (Total)
I rcn
Nic>el
Cii arc Grease
Prosphate 'Total)
Total Dissolved Solids
Total Sjspended Solids
Total Solids
Surfactants
Zinc
8392
Cooling Tower
	 RlDJtdO*IL_
L/Oay
238455.0
mg/1
1.4Z
	
9.8
4.9
3.3
0.02
0.02
0.48
0.03
1.0
3.25
886.0
2.9
889.0

1.5
L/I1WH
745.81
g/MWH
10.4


7.3
3.65
2.46
0.01
0.01
0.35




2.43
660.78
2.16
660.8

1.11
8135
Cooling Tower
Slowdown
L/Day
53959.0

7.09


102.91
0.02
0.004


0.014



7.43


943.45
3.89
946.73

0.48
L/HWH
321 .51
g/HHH"
2.28


33.14

0.001


0.005



2.39


303.74
1 .25
304.85

0.15
8696
Cool-ing Tower
Slowdown
L/Day L/MwII
217788.9 18.03
rng/l
2.2


25.2
<0.02
0.012
0.35
<0.005
0.32
<0.03
2.4
0.06
2860
33
2893

0.09
g/MWH
0.39
	
0.45
	
0.0002
0.002


0.005


0.043
0.001
51.5
0.59
52.19

0.001
7308
Cooling Tower
Slowdown
L/Day
(1)
mg/1
5.7
	
64
1.39
0.76
0.7
0.025
1.63
0.04
1.9
0.95
5111
59
5170

0.7
L/KUH
(1)
g/MWH
(1)















8231
Cool 1 ng Tower
L/Day
58Q.365.4
mg/1






0.009
O.l0


0.15.
0.03
1.0




8.3



0.02
L/MHH
555.37
g/MWH






0.004
0.06


0.08








4.0



0.01
9650
Cooling Tower
Blowdown
—T/TTTn 	 L/M^'M
1067370.0 1292.2
ng-/T •





0.07
0.044
0.05


0 29
0.03
4.0
0.08


16.0



2.04
g/H»H





0.09
0.05
0.06


0.37


5.16
0.1


20.67



2.63
co
      (1) Flow could npt be measured.

-------
Clarifier sludge consists of either alum or iron,  hydroxides
plus suspended and dissolved  impurities,  softening  sludge
consist  of  calcium  carbonate  and suspended and dissolved
impurities, and some  softening  sludges  may  also  contain
magnesium   hydroxides.   Filter  washes  contain  suspended
solids either carried over from the clarifier  or  contained
naturally in the unclarified water.

Demineralization  (ion  exchange)  is a process that removes
mineral salts by adsorption on a resin.  Two types of resins
exist: cationic (for the removal of  cations) ,  and  anionic
(for  the  removal  of  anions) .   These  resins may be used
separately, (one  following  the  other) ,  or  they  may  be
combined  in a mixed-bed  (demineralizer) ,  After a period of
use, ion exchange resins become  saturated  with  ions,  and
must  be  regenerated.   Anionic resins are regenerated with
sodium hydroxide solution followed by water rinse to  remove
excess sodium hydroxide.  The regeneration waste will have a
high  pH  and  will contain the exchanged anions, which are:
sulfate, chloride, nitrate, and phosphate.  Cationic  resins
are  regenerated  with  sulfuric  acid, and the regeneration
waste from those units will have a low pH and  will  contain
calcium, magnesium, potassium, and sodium ions.

Evaporation is simply a distillation process for the removal
of  impurities.  Evaporators usually consist of a horizontal
vessel heated by a  waste  heat  source,  which  is  usually
exhaust steam from the turbines.  Steam from the evaporation
of  water  in  the  vessel  is drawn off and condensed in an
external condenser.  To prevent a concentration  buildup  of
salts  which  contribute  to  scaling  problems  within  the
vessel, a portion of the water is  drawn  off  as  blowdown.
This blowdown has a high pH, and contains the same chemicals
present  in the raw water feed,  which have been concentrated
by a factor of three to five.  Calcium carbonate and calcium
sulfate precipitates may also be present in the blowdown  if
present   in   the   water   feed   in   sufficiently   high
concentrations. Phosphate is  sometimes  added  to  the  raw
water  feed  to  lessen  the  precipitation of calcium salts
Reverse osmosis is a process used by some plants  to  remove
dissolved  salts.   The  technique consists of forcing water
through a semipermeable membrane under  a  pressure  greater
than the osmotic pressure of the dissolved salts.  The salts
are  concentrated  on  one  side  of  the  membrane  and the
purified water is collected on the other.  The  concentrated
salt solution  (brine) is discharged as a waste.

Chemical  Additions.  After treatment, various chemicals are
added to the boiler makeup water.  These  include  hydrazine
or  sodium  sulfite  (to  remove  dissolved  oxygen) , sodium

-------
RAW WAHR
l\C 1 D
CAT1M
^-r-^


,,
DhGASI-
FILR
!
                                           CAUSTIC
                                                  AN I OK
            WASTl
                                                      DEIONIZfD WATER
                                                  WAS IF
     Two-Bed  Ion Fxchanqe  Oerrnneral i?er !/'ith  Deoasifier
                          * MIXEi)
                             RLSIK
                    ACID
                                     WASTf
                                     DEIONIZED WATER
           Mixed-Bed Ion  Exchange  Demineratizer
                               PRCiSURF
                               VC5SEL
     FEED
     WATER
           HIGH PRESSURE
              PUMP

  SEMI
PtRMEABLE
MEMBRANE
   •PERMEAT
    (PRODUCT
    WATER)
                              REGULATINCi
                               VALVt
                      CONCENTRATE (WASTEWATER)

            Reverse  Osmosis Membrane Filter
Finure V-7.    Commonly Used Make-Up Water  Treatment Methods
                                45

-------
 RAW WATER
  SLOWDOWN


WASH

i
•
FILTER

1
WASTEWATER
FILTERED
WATER
S^>CL
J
                                                            DEIONIZED
                                                             WATER
                                                     WASTEWATER
Lime  Softening, Filtration  & Sodium Zeolite Water Treatment  Process
              PRE-
           TREATMENT
                                                      FEED
                                                      WATER
                       CONDENSER
                              JTWiT"

                               COND.
                                          EVAPORATOR
                                       I
                 TREATMENT
                 CHEMICALS
Evaporation  Process

  U

   CLARIFIER
                 RAW WATER
                                           CLEAR _
                                           WATFR
 CONDENSED
BOILER FEED
                                                      EVAPORATOR
                                                      SLOWDOWN
                              SLUDGE
                       Clarification Process
      FIGURE V-7.    Commonly  Used Water Treatment  Methods
                             (Continued)
                               46

-------
phosphate  (to  prevent  scale  formation  by  precipitating
calcium and magnesium salts), and sodium hydroxide, ammonia,
morpholine, or cyclohexylamine  (to control pH).

Figure  V-7  shows  six  (6)  commonly  used water treatment
methods.

Water Use

Boiler Makeup Water.  Sixteen  of  the  twenty-three  plants
surveyed  provided  information on their boiler makeup water
usage.  The water use  in  liters  per  MWH  at  the  plants
studied is given below.

          Plant No.             Water Usage Liters/MWH

            9650                  36.76
            9369                  79.56
            9371                  36.73
            8816                  29.93
            9585                   1.59x102
            8696                   4.15
            8135                   4.03x10.1
            9163                   1.32x102.
            6387                   1.08x10.3
            8356                   1.78x102^
            8392                   1.19x10.3
            6293                   6.81
            7968                   3.116x102
            6421                   4.58x101
            6294                   1.06x102.
            8231                   5.43x101

The water usage data was plotted on log-log paper versus the
production rate to determine the effect of the plant size on
the  quantity of water used.  The results of the statistical
analyses suggest that, based on the available data, there is
a fair correlation between water use for boiler  makeup  and
production rate.  The overall trend appears to be a decrease
in water usage with increasing production rate.

Demineralizer  Reqenerant  Wastes.   Thirteen of the twenty-
three  plarits  surveyed  presented  information   on   their
demineralizer  system  regenerant  water  usage.   The water
usage in liters per MWH  at  the  plants  studied  is  given
below:

          Plant No.                Water Usage, Liters/MWH

                                       Regenerant
            9650                       65.75
            9369                       17.51
                            47

-------
            9371                       27.55
            9585                        3. 24x102^
            8696                        U.56
            9163                       18.38
            6387                       13.46
            8356                        4.22x102
            8392                        7.1
            6293                        9.01
            8875                       11.35
            6421                       39.23
            6294                        5.69

The water usage data was plotted on log-log paper versus the
production rate to determine the effect of plant size on the
quantity  of  water  used.   The  results of the statistical
analysis suggest that, based on the available data, there is
no correlation at all between water use for the regeneration
of demineralizer  system  and  the  production  rate.   This
result  is  not  unexpected,, since the regenerant water is a
function of intake water quality, frequency of  regneration,
size of individual demineralizer plants, etc,

Raw Waste Load

The raw wastes from the water treatment process include:

    o    Mineral   salts,   suspended   solids   and   other
         constituents removed from the raw water supply.

    o    Chemicals used by the water treatment units.

Of the twenty-three plants visited, three use hot  lime-soda
ash  softening  and  zeolite ion exchange,  two use hot lime-
soda ash softening, filtration, and  zeolite  ion  exchange,
two use reverse osmosis and deionization, twelve use cation-
anion  ion  exchange, one uses deionization and evaporation,
one uses hot lime-soda ash softening, zeolite  ion  exchange
and evaporation, and one us€»s deionization and evaporation.

Solid  wastes  are not generated in large quantitites during
the regeneration process.  The major source of solid  wastes
are calcium carbonate and magnesium hydroxide from the lime-
soda  ash softening processes.  Waterborne wastes for plants
in terms of grams per MWH are given in Table V-2.

Wastewater Treatment

Fifteen plants discharge water treatment  waste  streams  to
POTW.    Five   of   these  plants  practice  some  type  of
pretreatment  before  discharge.   Plant  6293   uses   lime
settling;  plant  9369 uses equalization and neutralization;
plant  7308  uses  equalization,  neutralization,  and   oil
                            48

-------
skimming;  plant  8696  uses equalization, settling, and oil
skimming and plant 7116 uses  equalization,  neutralization,
and settling.

Effluent Waste Loads

Table  V-3  shows  the  composition of pretreated wastewater
discharge to the POTW in terms of  concentration  and  waste
loads for plant 6293.

BOILER SLOWDOWN

To  prevent  the accumulation of calcium and magnesium salts
on the internal  boiler  surfaces,  phosphates  are  usually
added  to precipitate the salts.  The precipitate is removed
continuously or intermittently by withdrawing a  portion  of
the  boiler  water as blowdown.  Blowdown wastes have a high
pH, may, depending on boiler pressure contain high dissolved
solids concentration.  Blowdown from  boilers  treated  with
phosphate  may contain hydroxide alkalinity and will contain
phosphate, and blowdown from boilers treated with  hydrazine
will  contain  ammonia and depending on boiler pressure, may
also contain sulfite.

Raw Waste Load

The raw wastes from boiler blowdown contain:

    o    Products of chemical additives to remove oxygen;

    o    Chemical additives  to  prevent  scale  or  inhibit
         corros ion; and

    o    Concentrations  of  dissolved  solids   and   other
         constitutents present in the boiler feedwater.

Boiler  blowdown does not generate large quantities of solid
waste.  Sludge, consists principally of  precipitated  iron,
calcium  and  magnesium  salts, where phsophate treatment is
used and is maintained in a fluid form and  removed  by  the
blowdown.   Blowdown  may  contain ammonia when treated with
hydrazine.

Waterborne wastes for two plants in terms of grams  per  MWH
are given in Table V-U.

The  waterborne  raw  waste  values  indicate that the major
components  by  weight  in  boiler  blowdown   streams   are
dissolved   solids,   chemical   oxygen  demand,  and  total
phosphates.

Wastewater Treatment

-------
                       Table V-2   RAW  WASTE FLOWS AND  LOADINGS  -  WATER  TREATMENT
PlAKl NO.
VASTEVATCR 10UHCE
tLO»
PARAMETER
COOj
BroMlde (Bronatt)
COO
CfcromiiiM
Chronlue'6
Copper
Cja.ilde (Tot a
0.02
0 005
0.02
0.005
0 07
O.OJ
1.0
0.05
174
1.0
174
0.011
0.02
I/HUH
(1)
9/Ngt,














(387
Blo«do.n _.
WCdr
17166.7
*9/l
1.8
.---
?OQ
0.11
0.004
0.15
0.014
10.4
0.09
1.0
1004
9440
10444

0.32
47.69
9/MWH
0.08
	
9 53
0.005

0.007
0.0006
0.49
0.004

47.88
450.2
98.08

o.ots
6387
— , LLoiiUJiiL __„ 	
L/Day
7570
•9/1
10.4

cr I
0.1
0.007
0.12
0.005
0.44
0.25
1.0
22980
44
23024

0.09
252 33
9/HWII
2.62

Ml. 55
0.0?
0.001
0.03
0.0011
0.11
0.06

5798.6
11.1
5809.7

0.02
6387

I/Day
408'S
•9/1
15.2
•
7Ł.C
0.02
0.005
0.02
0.006
0.33
0.03
1.0
6.20
2228
93
2321

0.11
L/
113.
55
9/H.rt
1 .
72

:



O.OJO'.
0 002
o.ocot
0.
043

0.
252.
105.
263.
7
9
6
t

0.
01
82)1
Denlncrallzer
Rpgpncr tlon
1/04X
227IU
m9/l





0.07
0.006
0.02


1.26
0.14
13.2
31


	
0.06
L/niH
21.73
g/MUH





C.001
0.0001




0.02
0 003
0 28
0.63


	
0.001
8231

'\-P'J
dn.e
IW/I





0.02
0.005
0.02


0.03
0 03
8 2
6.8


0.38
0.01
U'.'M
2,46
Q/ttlH

















0.02
O.OU


0.0009

9650
Soqpfif rat Ion
il'J>/
1105 T.
*'.l\





0.2
0 01
0.59


9.46
0.2
1 U
U.7



0.21
I /'•-••
ti e
ured.

-------
Table V-2. RAW  WASTE FLOWS AND  LOADINGS - WATER  TREATMENT
                        (CONTINUED)
PLANT NO.
WASTEWATER SOURCE
FLOU

PARAMETER

BOD5
Bromide (Bromate)
COO
Chromium (Total )
Chromi um+6
Copper
Cyanide (Total)


Nickel
Oil and Grease
Phosphate (Total)
Total Dissolved
Soli,ds
Total Suspended
Solids
Total Solids
Surfactants
Zinc
8696
Cation Demin-
e r a 1 i z e r
X. R e q e n e ra t i o n
L/Day L/MWH
\J1355{21 0.94
mg/1 q/MWH
6.0 0.005
0.03 0.00002
13.6 0.012
0.07 0.00006
0.008 Neg.
1.3 0.001
v-0.005
i fi 9 n n n Q
I . u c u . uuy
<0.03
<1 .0
14.0 0.013
3960 3.72
30 0.03
3990 3.75
<0.01
0.03 0.00002
7308
Evaporator
Bl owdown

L/Day L/MWH
(!) (1)
mg/1 g/MWH
5.16 (1)
	
20.8
0.08
0.036
2.61
0.028
09 9
. C-L.
<0.03
1 .9
12.6
2532.66
14.5
2547.16

0.44
7308
Zeol i te
Softener Back-
Wash
L/Day L/MWH
4920.5(2) 0.29
ing /I g/MWH
27 0.008
0.07 Neg
384 0.11
<0.02 	
0.016 Neg
0.13 Neg
<0.005 	
^*nc7 - _ - - -

0.20 0.00005
1.4 0.0004
0.5 O.O'OOl
28066 8.21
18.4 0;005
28084.4 8.22
0.021 Neg
0.08 0.00002
   (1)  Flow could
   (2)  Discharges
not  be measured
1  hour per day
                             51

-------
Table V-3.  EFFLUENT FLOWS AND LOADINGS  - WATER  TREATMENT
PLAHT MO.
WASTEWATER SOURCE
FLOW
PARAMETER
B005
Bromide (Bromate)
COD
Chromium
r h r Q m i nm + 6
Copper
Cyanide (Total)
Iron
Nickel
Oil and Grease
Phosphate (Total)
Total Olssolved Solids
Total Suspended Solids
Total Solids
Surfactants
21nc
6293
Lime Softener Effluent
L/Day L/MWH
1.6351.2 68.13
mg/1
1.5

5.9
0.02
0.026
0.02
0.005
1.23
0.03
1.0


152.0
245.0
397.0
0.011
0.2
g/MWH
0.1

0.4
0.001
0.001
0.001

0.08






10.35
16.69
27.04
0.0001 ,
0.0001
8696
Diluted Demineral izer
L/Day L/MWH
54504 4.57
mg/1
34.0
- - - -
81 .0
0.05
.02

0.85
0.09
9.36




25.02




0.04
g/MWH





0.0007
0.0001



0.020
0.001
0.13




0.35




0.0005

-------
Thirteen plants discharge boiler blowdown to POTW, of which,
three practice some type of pretreatment.  Plant  9369  uses
equalization    and    neutralization,   plant   7116   uses
equalization, neutralization and  settling  and  plant  7308
uses equalization, neutralization and oil skimming.

Effluent Waste Loads

Although  recovery  of the blowdown is not practiced in most
cases, this option should be considered since  the  blowdown
water  is  almost  always of better quality than the make-up
water.

Information was not available on treated waste streams  from
boiler blowdown.

MAINTENANCE CLEANING

Boiler  Tubes.  Boiler tubes must be cleaned occasionally to
remove accumulations of  scale.   A  multitude  of  cleaning
mixtures   are  used  to  accomplish  this  purpose.   These
include: alkaline cleaning mixtures  with  oxidizing  agents
for   copper   removal,  acid  cleaning  mixtures,  alkaline
chelating  rinses,   organic   solvents,   and   proprietary
solvents.    Wastes  from  these  cleaning  operations  will
contain iron, copper, zinc, nickel, chromium, hardness,  and
phosphates.   In addition to these constituents, wastes from
alkaline  cleaning  mixtures  will  contain  ammonium  ions,
oxidizing  agents,  and  high  alkalinity;  wastes from acid
cleaning mixtures will contain fluorides, high acidity,  and
organic  compounds;  wastes  from  alkaline chelating rinses
will contain high  alkalinity  and  organic  compounds;  and
wastes  from most proprietary processes will be alkaline and
will contain organic and ammonium compounds.

Boiler Fireside Cleaning.  The fireside  surface  of  boiler
tubes  collects  airborne  dust,  fuel  ash,  and  corrosion
products.  These materials are removed  from  time  to  time
with  high-pressure  hoses.   Alkaline chemicals may be used
for safety and neutralization.

Wastes from this operation  will  be  more  or  less  acidic
depending  on  the  sulfur  content  of  the  fuel, and will
contain hardness, suspended solids, iron, nickel, zinc,  and
other metals.

Air  Preheater  Cleaning.   Air  preheaters are used to heat
ambient air that is used for combustion,  and  collect  soot
and  fly  ash.  High-pressure hoses are used to remove these
materials.  The wastes from this operation will be  more  or
less  acidic,  depending  on the sulfur content of the fuel,
and will contain suspended solids,  magnesium  salts,  iron.
                            53

-------
                        Table V-4.
RAW  WASTE  FLOWS AND  LOADINGS - BOILER SLOWDOWN
PLANT NO.
WASTEWATER SOURCE
FLOW
PARAMETER
BODg
Bromide (Bromate)
COD
Chromi urn (Total )
Ch romi um+6
Copper
Cyanide ( lotal )
I ron
Nickel
Oil and Grease
Phosphate (Total)
Total Dissolved Solids
Total Suspended Solids
Total Solids
Surfactants
Zinc
6293
Boiler Slowdown
L/DAY
17030.4
mg/1
11.7
	
157.0
0.02
0.007
0.19
0.005
1.4
0.03
2.2
18.7
1405.0
2.7
1407.7


0.05
L/MWH
70.96
g/MWH
0.83


11.1


0.0001
0.01


0.1


0.15
1 .32
99.7
0.19
99.9


0.003
8392
Boiler Slowdown
L/DAY
1665.4
mg/1
10.8


2.0
0.02
0.009
0.06
0.014
0.08
0.03
1 .0
19.8
118.0
6.9
125.0


0.02
L/MWH
5.20
g/MWH
0.06
	
	
0.000]
Neg.
0.0003
Neg.
0.0004




0.1
0.61
0.036
0.65


0.0001
8231
Boiler Slowdown
L/DAY
5715
mg/1
	
	


0.02
0.005
0.02


0.03
0.03
14.8
0.05


31




0.01
L/MWH
5.47
g/MWH


















0.08




0.17






9650
Boiler Slowdown
L/DAY
(1 -
mg/






0.02
0.005
0.0?


0.03
0.03
5.3
0.05


8.3




0.02
L/MWH
(1)
gJHWH






























Neg.
en
           (1) Flow could not be measured.
           (2) pH values  for plants:  #6293=12.0, #8392-10.6, #8231=9.0,  #9650=9.5

-------
copper,  nickel, and chromium.  Vanadium may also be present
if the plant is oil-fired.

Stack Cleaning.  High pressure water is used  to  clean  fly
ash  and soot from stacks.  The frequency that this cleaning
is required is dictated by the  fossil  fuel  used.   Wastes
from  this  operation  may contain suspended solids, metals,
oil, and high or low pH values.

Cooling Tower Basin Cleaning.  Deposits of carbonates on the
bottoms of cooling towers and growth  of  algae  on  cooling
towers  are  removed  occasionally  with  water.  The wastes
contain suspended solids as a primary pollutant.

Miscellaneous Small Equipment.  Occasional cleaning of plant
equipment such as condensate coolers, hydrogen coolers,  air
compressor  coolers,  and  stator  oil coolers is performed.
Detergents, wetting agents, and hydrochloric acid are  often
used  during  cleaning.   Wastes  from these operations will
contain suspended solids, metals, oil, and low or high pH.

Raw Waste Load

The raw wastes from  maintenance  cleaning  consist  of  the
cleaning   solution   and  the  material  removed  from  the
equipment.  Boiler fireside, air preheater, and boiler  tube
cleaning  account  for  most  of the wastewater generated in
maintenance cleaning.  No plants were performing maintenance
cleaning during the time of our visitation and sampling.

Typical  waterborne  wastes  are  shown  in  Table  V-5  for
wastewaters  from  air  prehater,  boiler fireside, and tube
cleaning.  This information was obtained from Reference  14.
Information  was  not  available  on cooling tower basin and
stack cleaning wastewaters.

The major components by weight in the three  cleaning  waste
streams  are  dissolved  solids, hardness, metals, chlorides
and sulfates.

Water Use

At infrequent intervals,  certain  power  plants  components
such   as  condensate  coolers,  oil  coolers,  compressors,
boilers, etc., are chemically cleaned  with  a  solution  of
hydrochloric  acid,   or a detergent.  Typical flow rates are
summarized below.

Waste             Waste                      Typical Flow
Stream	Flow or Volume   Frequency	or Volume	

Maintenance Cleaning
                            55

-------
Boiler Tubes  3-5 Boiler     Once/7 Months-  1 boiler per
              Volumes        once/100 mos.    1-2 hours

Boiler Fire-  24-720xl03gal  2-8/yr          300,000 Gal
side

Air Preheater U3-600xlQ3gal  4-12/yr         200,000 Gal
Misc. Small    No Date       	     	
Equipment

Stack          No Data       	     	

Cooling Tower  No Data       	     	
Basin

Wastewater Treatment

Plant 7308 discharges maintenance cleaning wastewater  to  a
POTW  through an industrial wastewater collection system and
this was the only plant surveyed which disposed of  cleaning
wastewaters in this way.

Effluent Waste Loads

Information   was   not   obtained  on  the  composition  of
maintenance cleaning wastes after treatment.

ASH-HANDLING SYSTEMS

One of the products of the combustion of  coal  and  oil  in
electric utilities is ash.  Ash which falls to the bottom of
the  furnace  is  called  bottom  ash;  ash which leaves the
furnace with the flue gas is called fly  ash.   Fly  ash  is
usually  collected  from coal-fired units with electrostatic
precipitators and from large oil-fired units with  cyclones.
The   function   of   ash-handling   systems  is  to  remove
accumulated bottom ash and fly ash.

Two types of ash-handling systems exist: dry systems and wet
systems.  Dry systems use a  mechanical  conveyance  devices
for  the  transport  of  ash  and are not a source of liquid
wastes.  Wet systems use water for the transport of ash, and
in many cases, discharging it into a settling pond or basin.

Wet systems are either of the open type or the closed  type.
Open  systems  discharge supernatant from the settling basin
into either a receiving water or  a  POTW.   Closed  streams
recycle  the supernatent back to the ash-transporting sluice
for  reuse.   Figure  V-8   shows   a   flow   diagram   for
recirculating   bottom  ash  system.   Periods  of  extended
                            56

-------
Table V-5.  RAW WASTE FLOWS AND LOADINGS - MAINTENANCE CLEANING
No. of Plants
Wastewater Source
Cleaning Frequency
(#/yr)
Flow (1000 liter)
Parameter (Kg)
BODc
b
Bromide (Bromate)
COD
Chromi urn (Total )
.. . +6
Cnronn urn
Copper
Cyani de (Total )
I ron
Nickel
Oil and Grease
Phosphate (Total)
Total Dissolved
Solids
Total Suspended
Solids
Total Solids
Surfactants
Zi nc
7 plants
Air Preheater
4-12
163-2,271
Kg
0-6.82


2.6-15.9
0.21-26.88


0-2.02


0.97-3862
8.14-170.38


0.02-2.66
1 ,448-20,096
217-4,898
1 ,188-29,744


0.13-11 .36
2 plants
Boiler Fireside
2-8
91-2,725
Kg
0


8.63-515.00
0.01-0.45


0-0.11


13.63-408.90
0-13.63


0.12-5.04
1 ,363-15,948
54.07-1 ,736
1 ,817-18,551


0.91-13.04
7 olants
Boiler Tubes
0-2
568-18,622
Kg




0.45-19,387
0.21-10,524


0.06-931 ,185


0.51-595.96
42,592-133,826


0.02-3.48-
111 .11-43,598
0-1 ,590
111 .11-48,868


0.35-391 ,098
                          57

-------
rainfall may cause problems with closed systems, since  some
water  may  have to be withdrawn from the settling basin and
discharged.  Similarly,  extended  periods  of  dryness  may
evaporate  excessive  amounts  of  water  from  the settling
basin, requiring the addition of supplementary water to  the
system.

Ash  pond  effluents  from  coal- fired plants contain a wide
variety of constitents whose concentrations can vary  widely
depending  on  the  particular  coal  used.   Generally, the
overflows contain high levels of dissolved solids, suspended
solids, hardness, sulfate, sodium, magnesium, chloride,  and
alkalinity.   Metals originally present in the coal may also
be present.
Ash  is  produced  in  oil-fired  plants   in   very   small
quanitities.  It has been found that oil ash does not settle
as  well as coal ash.  In some utilities, the oil fly ash is
recycled  into  the  furnace,  increasing   efficiency   and
reducing the disposal problem..  Ash pond overflows from oil-
fired  plants have some of the same characteristics as those
from coalfired plants, and  may  additionally  contain  high
concentrations of vanadium.

Table  V-6  contains  an  itemization  of  the  types of ash
handling systems used  by  the  plants  that  were  visited.
Water Use

Of  the twenty- three plants visited in this study, only four
used water to convey fly and bottom ash to  ash  ponds;  the
remaining plants use dry ash transport systems.  Of the four
plants  utilizing  wet systems, all were coal-fired.   Plant
9163 uses 2.65x102^ liters per  MWH,  the  only  plant  using
water  for  fly ash transport.  The other three plants 6387,
8356, and 6294, respectively use 43.09, 3. 61x10!  and  11.39
liters per MWH for bottom ash transport.

Raw Waste Load

Oil-Fired  Plants.  Fuel oils contain only about one percent
of the amount of ash commonly found in  coal,  consequently,
ash    disposal   problems   from   oil-fired   plants   are
significantly less.

Fly  Ash.   Many  of  the  oil-fired  plants  visited   used
mechanical  cyclones  to remove fly ash from the flue gases.
A dry system is usually used to remove  the  collected  ash.
In  other  plants, no fly ash collection system is necessary
because of the low ash content of the oil  used.   In  these
plants,  most  of  the ash in the flue gases collects on the
interior surfaces of the  boiler  and  is  removed  by  high
                            58

-------
EVAPORATION LOSS
 ASH  HANDLING
    SYSTEM
                  EVAPORATION

                     LOSS

                      ; i
                      RECYCLE
                       MAKE-UP
                                                  RAINFALL
                                                     1
                      SETTLING POND
                                                         OVERFLOW
                                            ASH SLUDGE FOR
                                              DISPOSAL
FIGURE V-8.
Flow Diagram for Recirculatlng Bottom
          Ash System
                     59

-------
                                Table  V-6.   ASK  DISPOSAL  METHODS
PLANT NO.
9600
9650
9369
9371
7435
3816
9585
7116
<3596
3135
9163
6387
8392
6293
7308
8875
7968
6421
6214
6294
TYPE OF PLANT
Oil and Gas
Oil and Gas
Oil and Gas
Oil and Gas
Coal , Oi 1 , end Gas
0 i 1 a n d G a s j
Gas
Oil and Gas
Oil and Gas
Oil and Gas
Coal
Coal
Gas
Coal
Oil
Oil and Gas
Coal and Gas
Oil and Gas
Coal
Coal and Gas
ASH
FLY ASH

1
3
3
3
1

3
9
'
3,5
3

3

1
3

4
3
DISPOSAL
None Requ





None Requ


None Requ


None Requ

None Requ


None Requ


SYSTEM
BOTTOM ASH
i red





i red


i red


i red

i red


i red



2
4
2
4
2

4
2

4
6

7

2
7

4
8
CM
O
                             Key:   (1)   Soot  blowing  steam
                                   (2)   Fireside  washing
                                   (3)   Dry  collection  system  from  electrostatic  and/or  mech-
                                        anical  precipitators,  ash  then  hauled  to  landfill.
                                   (4)   Dry  collection  sy'stem-ash  landfilled.
                                   (5)   Air  wash  in stack to control   fly  ash-discharges  to
                                        POTW
                                   (6)   Wet  collection  system  with  settling  sump-(overf1ow
                                        from  sump' goes  to POTW)
                                   (7)   Vacuum  system using  steam,  ash  landfilled,  condensate
                                        from  steam goes  to  POTW.
                                   (8)   Wet  system discharging to  surface  water.
                                   (9)   Wet  system, does  hot discharge  to  POTW

-------
pressure  steam (soot blowing steam),. and passes through the
stack to the atmosphere.

Bottom Ash.  Some of the  oil-fired  plants  visited  needed
fireside  washing to remove bottom ashr other plants had dry
collection systems that removed ash for land disposal.

Coal-Fired Plants.  The amount of ash produced by coal-fired
plants is much  greater  than  that  produced  by  oil-fired
plants,  requiring  the  use  of  more  complex ash-handling
systems.

Fly Ash.  Electrostatic precipitators or mechanical cyclones
are used in most of the coal-fired  plants  to  collect  fly
ash.   The  collection  systems from these units are usually
dry, and the final ash disposal is on land.  One plant.  No.
9163,  used  an  additional  system  for  fly  ash  control,
consisting of a wash in the stack that discharged excess fly
ash to a POTW.

Bottom Ash.  Methods for  disposing  of  bottom  ash  varied
widely  among  the  coal-fired  plants  that  were  visited.
Plants 7485 and 9163 used dry  collection  systems  for  the
land  disposal of bottom ash.  Plant 6387 was the only plant
visited that used a wet transport system in combination with
a settling sump.  Two plants No. 6293 and 7628 used a vacuum
collection system with steam.  One plant. No. 6294,  has  an
ash  settling basin which overflows to surface water.  Plant
No. 6214 has a totally dry ash system.

Table V-7 shows raw waste loadi.ig for two plants,  6293  and
6387.

Wastewater Treatment

Oil-Fired  Plants.   Because  of the small quantities of ash
produced by oil-fired plants, none of the visited plants had
ash treatment systems.

Coal-Fired  Plants.   Only  one  plant,  No.  6387,  used  a
settling  basin  in  conjunction  with  a  wet ash transport
system.  Most of the other coal-fired plants had no need for
an  ash  treatment  system,  since  these  plants  used  dry
collection systems, followed by land disposal,

Effluent Waste Loads

Oil-Fired  Plants.   Effluents from ash cleaning of oilfired
plants are present for  those  plants  which  used  fireside
cleaning for ash removal.
                            61

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Coal-Fired Plants.  Plant No. 6387 is the only visited plant
that  discharged  a  significant amount of waste from an ash
handling system to a POTW.  The discharge  consists  of  the
overflow  from  the  ash settling sump.  Treated effluent is
shown in Table V-8.

DRAINAGE

Floor and Yard Drains.  Floor and yard drains collect wastes
from leakage  and  numerous  cleaning  operations,  and  may
discharge  to a POTW.  The waste will contain dust, fly ash,
coal dust from coal-fired plants, oils, and detergents.

Coal Pile.  The storage  of  large  quantities  of  coal  is
necessary   for   coal-fired  plants  to  insure  continuous
operation and to simplify delivery by the supplier.   A  90-
day  supply  is normally maintained.  Coal storage piles are
of two types: active and storage.   Active  piles  are  used
continuously  and  are subject to infiltration by rainwater.
Storage piles are used for the long-term  storage  of  coal,
and  are  usually  protected from rainfall with some sort of
seal, which can be either a layer of asphalt or a  layer  of
fine coal dust covered with lump coal.

Waste  discharges from coal storage piles are the product of
drainage from rainfall.  This drainage can be either  acidic
or alkaline.  Acid drainage is the result of the reaction of
pyrite  (FeSŁ)  with  water  and oxygen, which produces iron
sulfate and sulfuric acid.  This type of drainage is  highly
acidic, has a low pH, and contains a large amount of ferrous
iron  and  some aluminum. Alkaline drainage occurs when acid
drainage is neutralized by alkaline material present in  the
coal,  or  when the coal has a low pyrite content.  Alkaline
drainage is characterized by a pH of 6.5 to 7.5 or  greater,
little  acidity,  and  significant concentrations of ferrous
iron.  If the ferrous iron concentration is high enough, the
iron may precipitate upon oxidation and hydrolysis.

Drainage from coal piles may  contain  in  addition  to  the
aforementioned    constituents,   high   concentrations   of
dissolved solids and significant amounts  of  copper,  zinc,
and  manganese. Other materials may also be present that are
the result of the reaction of sulfuric  acid  with  minerals
and organic compounds present in the coal.

Raw Waste Load

Coal  Pile.   Almost  all  of  the  plants that were visited
allowed coal pile drainage to drain to  either  the  surface
water, storm sewers, or nearby land.  An exception was plant
No.  9163,  which  stored  all  of its coal under roof, thus
eliminating any drainage problems.
                            62

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Table V-7.
RAW WASTE FLOWS AND LOADINGS - ASH HANDLING
PLANT NO.
WASTEWATER SOURCE
FLOW
PARAMETER
BODC
b
Bromide (Bromate)
COD
Chromium
Chromi um+6
Copper
Cyani de (Total )
I ron
Nickel
Oil and Grease
Phosphate (Total)
Total Dissolved
Solids
Total Suspended
Solids
Total Solids
Surfactants
Zinc
6293
Ash Transport
Bl owdown
L/Day
2725?
mg/1
3.0
	
1235.0
0.37
0.030
0.16
0.005
76.0
0.24
1 .0
3.4
388.0
1144.0
1532~0


0.55
L/MWH
1 1 3. 55
g/MWH
0.34
	
140.23
0.04
0.003
0.018
0.0005
8.62
0.03
	
0.38
44.05
129.90
173.95


0.06
6387
Ash Transport
Bl owdown
L/Day
45420:0
mg/1
1.2
---
290.0
0.12
0.009
0.20
0.112
6.2
0.03
1.0
0.02
1894.0
1651 .0
3545.0


0.08
L/MWH
126.16
g/MWH
0.15


36.58
0.015
0.001
0.025
0.014
0.78
0.003




238.95
208.30
447.26


0.01
                     63

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Table V-8.    EFFLUENT FLOWS AND LOADINGS - ASH HANDLING
PLANT NO.
WASTEWATER SOURCE
FLOW
PARAMETER
BODC
b
Bromide (Bromate)
COD
Chromi urn
Chromi um+6
C o p p e r
Cyanide (Total )
I ron
Nickel
Oil arid Grease
Phosphate (Total)
Total Dissolved Solids
.Total Suspended Solids
Total Solids
Surfactants
Zinc
6387
Settled ash transport
effluent
L/Dsy
45420.0
mg/1
1 .0


43.1
0.02
0.011
0.2
0.012
0.33
0.03
T .0
0.02
2980.0
70.0
3050.0


0.02
L/MWH
126.16
g/MKH




5.43


0.001
0.002
0.001
0.04






375.97
8.83
384.80


0.002
                       64

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General chemical characteristics of coal pile drainage  were
discussed  under  the  previous heading.  Reference 16 lists
ranges for  some  of  the  elements  present  in  coal  pile
drainage, which are shown below:

         Element              Concentration Range, mg/1

         Copper                       1-4
         Iron                         0.1-5
         Zinc                         1-15

Floor  and Yard Drains.  Drainage from floor and yard drains
in most cases can  be  assumed  to  be  a  negligible  waste
source.  Many plants exercise meticulous care to prevent oil
leaks  and  spills  from reaching floor drains by using drip
pans and oil absorbing materials.  Some plants  particularly
those in open areas or in dry regions, have no need for yard
drains and have no drains installed.

Reference  16  list  characteristics of wastes from yard and
floor drains, which are summarized below:

        Parameter             Concentration Range (mg/1)

        BOD                           2-1
        TSS                           0-5
        pH                          Low-Neutral
        Surfactants                 Present
        Chromium                      0-20
        Lead                        Present
        Phosphorous                   0-10
        Oil and Grease              Present

Wastewater Treatment

None of the plants that were visited used any type  of  coal
pile drainage treatment system.

One  plant  No.  7116  discharged floor drainage (along with
other wastes) to a settling tank before discharge to a POTW.
Other plants discharged  floor  and  yard  drainage  without
treatment either directly to surface water or to a POTW.

Effluent Waste Loads

Information  was  not available on treated wastewater before
discharge to the POTW,

AIR POLLUTION CONTROL EQUIPMENT

Liquid waste disposal problems associated with air pollution
control equipment are mainly  limited  to  systems  for  the
                            65

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control  of  SO2.   Control,  systems  for SO2 can be further
divided into "throwaway" and "recovery" processes. Throwaway
processes produce a sludge or cake that must be disposed of.
Recovery processes produce either elemental sulfur, sulfuric
acid, or gypsum, which are marketable  to  some  degree  and
have  limited  disposal  problems.  The following discussion
will be limited to a throwaway process.

The greatest number of  existing  flue  gas  desulfurization
systems  (including  recovery  and  throwaway)   use tail-end
scrubbing  with  lime  and/or  limestone.   Those  scrubbing
systems,  installed after the boiler, remove particulates as
well as  sulfur  dioxide  by  reacting  the  flue  gas  with
slurries  of  lime or limestone forming calcium sulfates and
sulfites.  The calcium  sulfate/sulfite  sludge  is  usually
piped to large settling ponds.

A  small  number  of  existing  throwaway systems are of the
double-alkali type.  In these systems,  sodium  or  ammonium
salts  are  used  as a scrubbing solution.  After contacting
the  flue  gas,  the  scrubbing  solution  is  reacted  with
limestone or lime to precipitate calcium sulfite and sulfate
and   regenerate  the  solution  for  recirculation  to  the
scrubber.  Scrubber wastes consist of a dry filter cake.

Figure V-9 shows a flow diagram for an air pollution control
scrubbing system.

Wat er Use

None of the twenty-three plants visited in  the  study  used
water  to  control SOx emissions.  This can be accounted for
by the fact that the  majority  of  the  plants  burned  low
sulfur   (1 percent) coal or oil thereby eliminating the need
for air pollution control devices.

Raw Waste load

None of the utilities visited had flue  gas  desulfurization
equipment.  Wastes from these systems are mostly in the form
of sludges, which are disposed of on land.

Wastewater Treatment

None of the plants discharged SOx removal wastewaters to the
POTW.

Effluent Waste Load

Information was not available on treated wastewater.

MISCELLANEOUS WASTE STREAMS
                            66

-------
Sanitary Wastes,  Sanitary wastes from steam-electric plants
are similar to municipal domestic wastes with the absence of
laundry  or  kitchen  wastes.   The  volume of waste flow is
dependent upon the number of employees.

Plant Laboratory Wastes.  Many  steam-electric  plants  have
laboratories  for  the  chemical analysis of various process
streams  within  the  plant.   Depending  on  the   analyses
performed,  the  waste from this source will contain a large
variety of chemicals, albeit in small amounts.

Intake Screen Backwash.  Power plants that withdraw  cooling
water  from  a  natural  body,  such as a lake or river, use
traveling screens to prevent debris from entering the intake
system.   The  debris  from  these   screens   are   usually
collected.

Supplementing  Cooling Water Systems.  These cooling systems
are generally maintained for such uses as bearing and  gland
cooling  for pumps and fans.  The systems may be oncethrough
or recirculating.  Chemicals are  not  used  in  oncethrough
systems,   except   for   occasional   shock   chlorination.
Recirculating systems use water of high purity, supplemented
by  pretreated  makeup  water.   Chromates,   borates,   and
nitrates  are  used  in  recirculating  systems  to  prevent
corrosion.

Construction Activity.  The construction  of  buildings  and
equipment adjacent to power plants can cause the presence of
additional  amounts of suspended solids and turbidity in the
storm-water runoff due to the erosion of soil  disturbed  by
the construction activity.

Water Use

Hqu s eke e pi nq.   Housekeeping  water  usage,  which  includes
floor washing and sanitary water (bathrooms,  sinks,  etc.),
amounts  to  less  than  one  percent of the total.  Only one
plants of the twenty-three in the study had any  substantial
floor  wash water usage these being plant No. 6294 with 0.29
liters per MWH. The following  table  lists  the  water  for
sanitary purposes.

        Plant No.                  water Usage, Liters/MWH

          9600                         1.05
          9369                         7.96
          8816                         2.74
          9585                         6.23
          9163                         4.29
          6387                         6.73
          8356                        26.12
                            67

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                                                  STACK GASES
             STEAM TO TURBINES
                 BOILER
                      .   FLUE GASES  I
                            INI? T
                         SCRUBIIEH IIQIJOF]
FIGURE  V-9.   Flow  Diagram  For Air  Pollution  Control
                      Scrubbing System (Ref.  14)
                        68

-------
          6293                         4.73
          8392                         5.03
          8875                         t).4
          7968                        11.55
          6421                         6.00
          6294                         1.74

Miscellaneous  Cooling.  Miscellaneous cooling needs include
bearing cooling water, cooling  of  compressors,  and  other
extraneous  equipment* cooling needs.  Water usage varied for
six plants from a low of 1.59 liters per MWH for  plant  No.
9396  to  a  high of 1.45x10.4 for plant No. 8356.  Using the
least squares analysis method for  the  normalized  data,  a
coefficient   of   determination  of  0.945  was  calculated
indicating  that  approximately  94  percent  of  the   data
variance  could  be  accounted  for  by  the  least  squares
straight line.

Raw Waste Load

Sanitary Wastes.  Reference 14 states that  the  per  capita
sanitary  waste  load  is  generally 25-35 gal/day  (94.5-132
liters/day)  from steam-electric power plant.  The  reference
also  lists  the  number  of  employees  per  MW that may be
expected to be found at typical power plants:

    operational personnel:       1 per 20-40 MW
    maintenance personnel:       1 per 10-15 MW
    administrative personnel:    1 per 15-25 MW

The flow, BODJS, and suspended solids per capita load can  be
estimated by the following (14):

                      Flow         BODS            TSS

Office-Administrative 0.95 cu      30cj             70g[
(per capita)           m/day         (0.071b)      (0.15 Ib)
                      (25 gpd)

Plant (per capital)    0.133 cu     40g             85g[
                      m/day         (0.09 Ib)     (0.19 Ib)
                      (35 gpd)

Plant Laboratory Wastes.  The volume of wastes from in-plant
laboratory  can  be  assumed to be negligible.  Reference 14
suggests that if a  toxic  materials  problem  is  found  to
originate  from a laboratory drain, it may be appropriate to
either:  (1)  change the test procedure, (2)  contain the waste
for seperate treatment, or (3) remove  the  waste  from  the
site.
                            69

-------
Supplementary  Cooling Water Systems.  Wastes are discharged
from recirculating cooling systems  during  blowdown,  which
may  typically  be  twenty  liters per day with a settleable
solids content of  1-2  ppm  (14) .   Additional  wastes  are
discharged  during  drainage  and cleaning operations, which
are infrequent.

Plants which use  once-through  systems  may  discharge  the
effluent  from  the  entire  system  to  a POTW.  This waste
stream will probably contain chlorine,  and  the  stream  is
usually of significant volume.

Construction  Activity  and  Intake  Screen  Backwash.   The
nature and  duration  of  these  wastes  do  not  contribute
significantly to the total waste load.

Wastewater Treatment

Sanitary  Wastes.   Sanitary wastes are generally discharged
directly to POTW or  septic  tanks  without  treatment.   An
exception  is  plant  7116,  which pretreats sanitary wastes
(along  with  other  wastes)  in  a  settling  tank   before
discharge to a POTW.

Plant  Laboratory  Wastes.   Most  plants combine laboratory
drains with other sanitary plant plumbing, and discharge the
waste without pretreatment.

Supplementary Cooling Water Systems.  Supplementary  cooling
system  wastes are usually discharged directly, although one
plant 7116, discharged the waste to a settling  tank  before
discharge to a POTW.

Construction  Activity   and  Intake  Screen Backwash.  Most
plants do not treat these wastewaters.  Intake  screens  are
generally backwashed into the water source.

Effluent Waste Loads.

Information  is  not  available  on  treated  effluent  from
miscellaneous waste streams.

THE POTW PROCESS

Preliminary Physical Treatment

Most POTW employ initial physical  treatment  of  wastewater
for  the  removal  of  course  materials, settleable solids,
grease, and floating material.

Bar Racks and Comminutors.  These devices are  used  as  the
first  step  in  wastewater  treatment to remove large solid
                            70

-------
materials.  Bar racks consist of large, parallel steel  bars
placed  perpendicular  to  the flow of wastewater.  The bars
trap and retain large solidsr which are removed mechanically
by a series of vertically-moving rakes connected to a motor-
driven, endless chain belt.  The solids are scraped off  the
racks  with  large  mechanical  arms, and may then either be
collected for land disposal or ground in disintegrators  and
returned  to  the  flow.   Smaller POTW may use comminutors,
which are motor-driven cutting devices  partially  submerged
in  a  narrow  channel,  to grind up large materials as they
pass through.

Grit Chambers.  Grit chambers are usually  found  in  larger
POTW.   They  are generally located after bar racks, and are
designed to remove sand, cinders, or other  heavy  particles
that have high settling velocities.  Grit chambers may be of
two  types:  horizontal-flow,  and aerated.  Horizontal-flow
grit chambers  consist  simply  of  a  channel  designed  to
maintain  a  constant flow velocity regardless of the volume
of water passing through the channel.  The flow velocity  is
lowered sufficiently over that of the influent wastewater to
allow grit to settle to the bottom.  Removal of the grit may
be done either mechanically or by hand.

Aerated  grit  chambers  consist  of  a spiral-flow aeration
tank.   The  velocity  of  flow  in  aerated   chambers   is
determined by the volume of the tank and the quantity of air
that  is supplied.  Aerated grit chambers are always cleaned
mechanically.

Primary Sedimentation.  Primary sedimentation is used  after
preliminary removal of solids in racks and grit chambers and
prior  to  biological  treatment.   The  purpose  of primary
sedimentation, when used prior to biological  treatment,  is
to   reduce  the  suspended  solids  and  BOD  load  on  the
biological treatment units.  This is accomplished in  large,
rectangular (or circular)  sedimentation tanks that provide a
sufficient  detention  time  for  the  removal of settleable
solids and floating material.   Grease  and  other  floating
materials  are  skimmed  off from the surface with skimmers.
Solids that settle to the  bottom  of  the  tank  (known  as
primary sludge)  are mechanically pushed into a hopper, where
they   are   collected   for   further  treatment.   Primary
sedimentation  tanks,  if  designed  properly  and  operated
correctly,  will  remove  50  to 65 percent of the suspended
solids in the influent wastewater and from 25 to 40  percent
of  the  BOD.   If primary sedimentation is used as the only
means of treatment, the effluent is usually  chlorinated  to
remove pathogens.

Secondary Biological Treatment
                            71

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Secondary  biological  treatment  is used to convert soluble
and colloidal organic material  into  settleable  flocculant
material  that  can  be removed in sedimentation tanks.  Two
types of  biological  treatment  processes  are  most  often
employed:   (1)    the   activated-sludge  process,  and  (2)
trickling filters.

Activated-Sludge  Process.   The  activated-sludge   process
consists  of  an  aerated  basin  containing a large mass of
microorganisms and flocculated solids, known  as  the  mixed
liquor, followed by a sedimentation tank in which the solids
are  removed.    The sedimentation tank may either be part of
the same structure as the  aeration  basin,  or  it  may  be
completely  separate.  Part of the solids that settle in the
sedimentation tank (the secondary  sludge)   is  removed  for
further  treatment,  and  part  is  recycled to the aeration
basin.  The effluent from the sedimentation tanks is usually
chlorinated.

Bacteria make up the largest portion of  the  microorganisms
present in the activated sludge, and are responsible for the
majority  of  the  waste  steibilization  that  occurs.    The
mechanisms by which bacteria stabilize a waste  is  twofold,
consisting  of:    (1)  consumption of organic matter, which is
partially oxidized to lower energy compounds  and  partially
converted  to  new cellular material, and  (2)  the production
of polymers and slime that bind bacterial  cells  and  other
suspended  material  into  flocculant  particles that can be
removed by sedimentation.  Other microorganisms may also  be
present,  such  as protoza, which consume bacteria that have
not flocculated, and  rotifers,  which  consume  small  floe
particles  that  have  not settled. Activated sludge systems
are usually from 55-95 percent efficient  in  removing  BOD,
and  from  55-95  percent  efficient  in  removing suspended
solids  (Figure V-10).

Trickling Filters.  Trickling filters consist of  a  bed  of
rocks or plastic material that support a growth of microbial
material   (slime layer).  Wastewater is sprayed over the top
of the bed, which is circular, with a rotating  distributor.
As the waste percolates through the bed, organic material is
adsorbed  onto  the  slime  layer.   At  periodic intervals,
partly because of the increase in  thickness  of  the  slime
layer, the microorganisms in the layer lose their ability to
cling to the surface of the filter media and the slime layer
is   washed   off   by  the  waistewater  (a  process  called
"sloughing") .  (Figure V-10) .

Trickling filters are divided into two categories:  low-rate
and  high-rate,   based on organic loading rates.  Both types
of filters achieve equivalent BOD removal efficiencies,  but
high-rate  filters are advantageous since they have a higher
                            72

-------
rate of BOD removal  (and thus  can  accept  higher  influent
flow  rates)  than  low-rate  filters.   This is achieved by
recycling  a  portion  of  the  influent  to  return  viable
organisms  back  to  the  filters.  Low-rate filters have no
recycle.  Both types of filters are followed by  a  settling
tank  (clarifier) to remove suspended solids produced during
sloughing.  The effluent from the settling tank is generally
chlorinated.   Trickling  filters  are  from  50-95  percent
efficient in the removal of BOD, and 30-92 percent efficient
in the removal of suspended solids.

Figure  V-11  shows  a  wastewater treatment process diagram
utilizing activated sludge or trickling filters.

Treatment and Disposal of Sludge.

The problem of disposing of sludges produced during  primary
and  secondary  treatment  is  one of the most complex tasks
faced by the engineer. Techniques for dealing  with  sludges
are varied, but most involve: (1) digestion, followed by  (2)
conditioning, and (3) dewatering and drying (Figure V-11).

Digestion is a biological process for reducing the volume of
sludge.   Two  types of digesters are in use:  anaerobic, and
aerobic.  Anaerobic digesters are closed,  heated  tanks  in
which   various   microorganisms  decompose  organic  and/or
inorganic matter without the  presence  of  oxygen,  forming
methane,  carbon  dioxide,  and  sludge solids.  The methane
that is involved during the process can be used as  a  fuel,
and  its  rate  of production is one of the best measures of
the  satisfactory  operation  of  the  digester.    Chemical
conditioning,   followed   by   centrifugation   or   vacuum
filtration, is usually used to treat  sludge  solids  during
anaerobic digestion.  Chemical conditioning involves the use
of  ferric  chloride,  lime,  alum,  or  organic polymers to
coagulate   the   solids   and   release   absorbed   water.
Centrifugation and vacuum filtration are physical operations
that  are  used to remove water from the sludge solids prior
to final disposal.

Aerobic digestion is much like the activated sludge process,
involving consumption of organic compounds in sewage  by  an
aerated  mass  of  microorganisms.  As the supply of organic
material run out, the microorganisms begin to consume  their
own  protoplasm.   Sludge  solids from aerobic digesters are
stable and are more easily dewatered by vacuum filtration or
drying on sand beds.

Advanced Waste Treatment

Many chemical constituents present in wastewater, especially
nitrogen  and   phosphorus,   are   slightly   affected   by
                            73

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INFLUENT
                             WASTE SLUDGE
                                                                   SLUDGE
                                                                   RETURN
                                                                             FINAL
                                                                         SEDIMENTATIO!\
                             ACTIVATED SLUDGE PROCESS
                                                I
                                                               EFFLUENT
     INFLUENT
                                       TRICKLING
                                         FILTER
                        SLUDGE
WET
WELL
                        SLUDGE RETURN LINE
                                                                     EFFLUENT
                              TRICKLING FILTER PROCESS
          FIGURE  V-10.  Flow Diagram of  Secondary Treatment  Methods
                                    74

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en
SCREENINGS
           INFLUENT
                                     GRIT
SLUDGE
                                                                                  WASTE SLUDGE
                                                   PRIMARY
                   BAR RACKS       GRIT CHAMBERS   SEDIMENTATION
                                                                 DERATION TANK     SETTLING TANK
                                                         ACTIVATED SLUDGE
                                                         'TREATMENT SCHEME
                                                   C1
.
L



|



!

>i
RETURN SLUDGE |






!




Y

                                                                                                              EFFLUENT
                                               CHLORINE
                                             CONTACT CHAMBER
SCREENINGS
           INFLUENT  [_
                                     GRIT
SLUDGE
                                                                                  ,,ASTE SLUDGE

                                                                  RETURN EFFLUENT        I


1
1
BAR RACKS

GR
|

— *
1

>


PRIMARY
IT CHAMBERS SEDIMENTATION


TRICKLING
FTITFRS

SE






\


*~
EFFLUENT
TTLING TANK CHLORINE
CONTACT CHAMBER
                                                         TRICKLING FILTER
                                                         TREATMENT SCHEME
                             FIGURE  V-ll.    Wastewater Treatment  Flow  Diagram

-------
                    ANAEROBIC SLUDGE
                       DIGESTION
           CHEMICAL CONDITIONING
                                              CENTRIFUGE
SLUDGE FROM SEDIMEN-
   TATION TANKS
DIGESTED
 SLUDGE
                                                                                                  CENTRATE
                       SUPERNATANT
                                              SLUDGE DISPOSAL SCHEME
                                           DEWATERED SLUDGE JO
                                           ULTIMATE DISPOSAL
                 FIGURE  V-12.     Flow  Diagram  for Sludge  Treatment

-------
conventional  primary  and  secondary treatment. Since these
chemicals can have adverse effects on the receiving water by
promoting the growth of algae  and  other  unwanted  aquatic
vegetation,  their  removal  is  desirable  in  some  cases.
Although tertiary treatment processes  are  still  uncommon,
their   use   is   receiving  considerable  attention.   Two
processes, nitrification for the removal  of  nitrogen,  and
precipitation   for  the  removal  of  phosphorus,  will  be
discussed.

Nitrification-Denitrification.  This process appears  to  be
the  most  promising  for  the  removal  of  nitrogen.   The
technique involves aerobic  conversion  of  ammonia  to  the
nitrate   form   (nitrification),   followed   by  anaerobic
conversion    of    the    nitrates    to    nitrogen    gas
(denitrification).    Both  steps  involve  the production of
specialized  groups  of  bacteria,  and   require   detailed
attention   to   operating   and  environmental  conditions.
Denitrification requires  the  addition  of  a  supplemental
carbon  source for successful operation; methanol is usually
used.  Nitrification-denitrification is from  60-65  percent
efficient  in  removing  nitrates.  Figure V-13 shows a flow
diagram of the nitrification-denitrification process.

Chemical Precipitation.  Precipitation of phosphorus can  be
achieved  by  the  addition of chemicals such as lime, alum,
and  ferric  chloride,  or  sulfate.   These  chemicals  are
usually  added  to  the raw wastewater and the phosphorus is
precipitated during primary  sedimentation,  however,  these
chemicals can also be added in the activated-sludge aeration
tank  or  to the secondary clarifier.  Removal of phosphates
by precipitation in primary sedimentation tanks is from 90—
95 percent efficient.

Flows of PQTW Receiving Steam-Electric Wastewaters

The wastewaters discharged  by  steam-electric  plants  vary
greatly  in  flow  and waste loadings.  For the twenty-three
plants  visited  during  this  study,   the   steam-electric
wastewaters  represented less than five percent of the total
POTW influent.   Table V-9 lists the combined discharge  rate
for each steam-electric plant along with the associated POTW
influent flow and treatment scheme.

Raw Waste Load

Waste  loads  in  the total combined waste streams discharge
from power plants are affected  by  any  occurrence  in  the
steam-electric   which   use   and   discharge  water.   The
waterborne waste loads in the combined discharge for six (6)
plants are shown in Table V-10.  The  major  pollutants  are
chemical  oxygen demand and dissolved and total solids, with
                            77

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lesser values of iron,  nickel,  phosphates  and  total  and
hexavalent chromium.

WASTE COMPARISON

Effluent  data  gathered  from  the eight (8)  plants sampled
during this study were compared with similar  data  gathered
in   support  of  the  "Development  Document  for  Effluent
Limitations Guidelines and standards of Performance for  the
Steam Electric Power Generating Point Source Category" (14).
Comparison was made to identify similarities and differences
in  the  quality  and  quantity  of aqueous plant effluents.
Waste streams for which data was  available  for  comparison
include:

    o    Recirculating Condenser Cooling Water

    o    Water Treatment Wastes

    o    Boiler Slowdown

    o    Ash Handling Wastes

These data may be found in Table V-11.

Recirculating Condenser Cooling Water

Flow data in this study tended to coincide with lower  flows
reported  in the development document  (14) and were similar.
Concentrations  of   BOD,   phosphate,   dissolved   solids,
suspended  solids,  total  solids, and zinc observed in this
study were  within  the  range  of  those  reported  in  the
Development  Document.   Concentrations of chromium, copper,
iron and nickel observed in this study tended  to  be  lower
than  those  reported  in  the  development  document.  This
difference is probably due to a number of factors,  includin
g  lower  influent loadings of these heavy metal components,
and less corrosive nature of the intake waters.

Water Treatment Wastes

Flows and parameter concentrations  of  wastes  observed  in
this  study  were  within the range of those reported in the
development  document  (14) .    Pollutants   observed   were
identical to those reported in Reference 14.

Boiler Slowdown

Flow  data  for  boiler  blowdown observed in this study was
within the  range  of  those  reported  in  the  development
document.   Pollutants  observed  were identical to those of
Reference 14.  Concentrations of all parameters observed  in
                             78

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VD
WASTE SLUDGE WASTE SLUDGE
pH ADJUSTMENT k ORGANIC PH ADJUSTMENT
CARBON I CHEMICAL
! SOURCE ,' ADDITION
SECONDARY
EFFLUENT
i
' \
S ^\ ' 1
r^ W A TT-J
f v y '
PLUG FLOW REACTOR
SI IIOGF RFT1IRN 	 - - 	
1
<
' /
X
PLUG FLOW REACTOR
. .._,,, Si !ID(5F RFTI1RN ... -.. 	

^\ FINAL EFFLUENT
1 , „. '*»
J
                                           SETTLING TANK
                                                                               SETTLING TANK
                              NITRIFICATION
DENITRIFICATION
                                              NITROGEN REMOVAL
                                                 SCHEME
               FIGURE  V-13.   Flow Diagram of  Nitrification-Dentrification Process

-------
Table V-9.
POWER PLANT AND POTW F'LOWS
Plant
No
9600
9650
9369
9371
7485
8816
9585
7116
8696
8135
9163
6387
8392
6293
7308
8875
7968
6421
6214
6294
Combi ned Flow
to POTU, gpd
U/d)
No data (plant has been
using POTW for only one
year)
100,00
(378,000)
8,350
(8,880)
15,000
(56,700)
1 ,580
(5,970)
2,000
(7,560)
600
(2,270)
Data incomplete
72,000
(272,293)
150,400
46,900
(177,000)
9,500
(35,900)
126,000
(476,000)
9,100
(34,400)
902,000
(3.41 x 106)
423,000
(1 .60 x 10°)
Data Incomplete
24,050
(93, 308)
No data - operates only
50 hours/yr
4, 2'jQ
(16, 088)
5OTW Average
Flow, gpd
(1/d)

97.5 x 106
(369 x 106)
2.4 x 106
(9.1 x 1Q6)
10.0 x 106
(22.7 x 106)
300,000
'. 1 .1 x 106)
350 x 106
(1 ,320 x 106)
4.5 x 106
(17.0 x 106)
3.5 x !06
(13.2 x 106)
350 x 106
(1 ,320 x 106)
% of POTW
f 1 ow

0.10
0.098
0.15
0.50
0.01
0.01
...
0.02
POTW
Treatment Scheme

Activated sludge,
anaerobic digestion
Rotati ng biological
surfaces; anaerobic
digestion
Activated sludge,
aerobic digestion
Activated sludge,
aerobic digestion
Activated sludge,
anaerobic digestion
Oxidation pond
Activated sludge
Activated sludge,
anaerobic digestion
No >OTV< at present - to be hooked up
to West Palm Beach POTW in 1978 - Sewers
presently run to ocean
10 x 106
C8 x 106i
220,000
(832,000)
1.5 x 106
(5.7 x 106)
Z x 106
(7.6 x 106)
315 x 106
(1 , 190 x 106)
31.1 x 106
(IZ'O x 106)
---
1 .4 x 106
(5.3 x 106)
1.4 x 10r
(5.3 x 10b)
1.1 x 106
(5..1 x 106)
0.47
4.3
8.4
0.46
0.29
1 .4
	
1.76
---
0.30
Trickling filters;
anaerobic digestion
Trickling filters;
no digestion
Activated sludge,
aerobic digestion
Activated sludge
trickling filters
anaerobic digesters
Primary treatment only
secondary treatment
facilities being built
Activated sludge,
trickling filters,
anaerobic digestion
	
Activated sludge
Activated sludge
Activated sludge
               80

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     Table V-10.  RAW  WASTE FLOWS  AND  LOADINGS  - COMBINED  DISCHARGE TO  POTW
PLANT NO
V.'ASTEWATER SOURCE
FLOW
PARf-X.ETER
30D5


COD
Chromi ufn
ChroiM un
Copper
Cyanide (Total)
Iron
Nickel
Oil and Grease
Phosphate (Total)

Total Dissolved
Solids
Total Suspended
Sol Ids
Total Solids
Surfactants

Zinc
6387
Combined Discharge
L/Qdy L/K'.-.'H
518,000 1870
mg/ 1 g/I'M
8.4 16


49.0 9!.6

-------
this study were similar to those reported in the development
document  with  the  exception of BOD, and zinc.  BOD values
observed in this  study  tended  to  be  higher  than  those
reported  in the development document.  Observed zinc values
tended to be lower.  Zinc concentrations are  understandably
lower  for  all discharges observed in this study due to use
of municipal water as influent water.

Ash Handling Wastes

Wastewater flows of ash handling  wastes  observed  in  this
study  were  within  the  range  of  those  reported  in the
development  document  (14) .,    Pollutants   observed   were
identical  to those reporte in Reference 14.  Concentrations
of parameters observed in this study were within  the  range
of  those  reported  in  the  development document, with the
exception of phosphate.  Phosphate  concentrations  observed
in  this  study  were  higher  than  those  reported  in the
development    document.     Higher    maximum     phosphate
concentrations  are  probably  due to the variable nature of
coal impurities.

Summary

Overall,   values,   of   effluent   flows   and   parameter
concentrations  observed in this study were similar to those
reported in data  referenced  in  the  development  document
 (14).   Pollutants observed were identical to those reported
in Reference 14.  The few parameters in this study that  lay
outside  the range of development document data tended to be
lower, reflecting the higher quality of the municipal  water
used  as  influent  water for the stations contacted in this
study.  Therefore, it may be  concluded  that  the  stations
reported   in   by  the  results  of  this  study  discharge
pollutants similar to those  (direct dischargers) affected by
the development document (14) .
                            82

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                                                       Table  V-11.

                                             COMPARISON  OF  PARAMETER VALUES

                                                    PLANT RA'J WASTES
i""""*-*^ WASTE
^---^STREAM
PARAMETER^-v^^

Fl OW (\ /DAY^

PARAMETER. NG/L
BOD L0
BUU Hj
COD L0
LJU H,
CHROMIUM

TOPPFR
hi
IRON -^
1KUN HT1
NICTFI

punCDUATC LO
RECIRCULATING
CONDENSER
COOLING WATER
THIS
STUDY
53,600
238,400
1.4
22
10
102
0.02
5
0.02
0.7
0.5
1.6
0.03
0.04
0.1
rMJi. MM It -gj— - -3 —
TDS L0
iui HI
TSS L0
lbb HI
TS ^°
15 HI
7TMP LO
Z.lNv. Hf
886
5,111
3
59
889
5,170
0.1
1.5
REF.14
109,000
27,258,000
2
18
36
436
10-
120
63 !
1 ,740
50
1,150
80
150
0.1
18
150
32,700
2
220
750
32,700
0.3
3,000
WATER TREATMENT
WASTES
THIS
STUDY
4,277
40,900
1.0
REF.14
150
135,000,000
0
40 344
2.0
0
76 | 44Q
0.02
0.1
O.C2
2.6
0.02
10.4
0.03
0.25
0.05
0.05
2.168
0.006
3.09
0.015
37.5
0.007
0.56
0.1
I 14.0 87.2
0.16
23,000
1.0
j 1,780
0.1G
1 ,958
0.02
2
35,235
0
300
15
36,237
0
0.44 j 4.5
BOILER SLOWDOWN
THIS
STUDY
5,715
17,030
10.8
11.7
2.0
157
.02
.02
.02
.19
.03
1.4
.03
.03
.05
19.8
118
1 ,405
2.7
31
125
1407.7
.01
.05
REF.14
4,530
4,233,000
0
6
0
784
0.001
1.5
0
0.3
0.03
0.3
0
0.13
0.01
29
5
26,006
0
300
5
26,077
0.1
1.2
ASH HANDLING
WASTES
THIS
STUDY
27,252
45,420
1.2
3.0
"240
1,235
0.12
0.37
0.16
0.2
6.2
76.0
0.03
0.24
0.02
3.4
388
1,894
1,144
1,651
1,532
3,545
0.03
0.55
REF.14
18,170
98,436,000
0
30
2
306
0.045
40
.009
100
0.001
2,100
0.01
10
0
0.24
83
32,423
4
236
35
32,412
0
0.52
00
U)

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                         SECTION VI

           CONSIDERATION OF POLLUTANT PARAMETERS
INTRODUCTION

Aqueous pollutants* originating  from  steam  electric  power
generating  facilities  are  considered  in  this section to
determine if they interfere with the operation of  publicly-
owned  treatment works  (POTW)  and if they are susceptible to
treatment by such treatment works.

THE CONSIDERATION OF POLLUTANT PARAMETERS

Pollutants were considered on the basis of  their  potential
for  interference  with the operation of treatment works and
on the  basis  of  their  treatability  by  such  worksr  as
follows:

    °    Potential interference with POTW

         The pollutant may impair the activity of biological
         treatment systems by either causing  the  death  of
         some   or   all  of  the  microorganisms  that  are
         essential  to  the  operation  of  the   POTW,   or
         impairing  the  activity of these microorganisms so
         that their waste-consuming efficiency  is  lowered.
         Examples  of  treatment units that may be adversely
         affected  by  pollutants  are:  trickling  filters,
         activated  sludge  units,  anaerobic digesters, and
         nitrification units.    Additionally,  consideration
         is  given  to  other characteristics of power plant
         discharges which would interfere with  other  parts
         of the POTW such as transport piping.

    o    Susceptibility to treatment

         Pollutants were considered that are not removed  or
         that  are  removed inadequately by treatment works.
         For those pollutants which are  partially  removed,
         the  problem  of disposing the sludge that contains
         such pollutants is also considered.

The remainder of this section is devoted to a discussion  of
the  properties  of the pollutants considered, the effect of
these pollutants on treatment works, and their  treatability
in treatment works.
                            85

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PROPERTIES OF POLLUTANT PARAMETERS CONSIDERED

Acidity and Alkalinity -

Although  not  a  specific:  pollutant,  pH is related to the
acidity or alkalinity of a. wastewater stream.  It is  not  a
linear  or  direct  measure  of  either,  however, it may be
properly used as a surrogate to control both excess  acidity
and  excess  alkalinity  in  water.   The term pH is used to
describe the hydrogen ion - hydroxyl ion balance  in  water.
Technically, pH is related to the hydrogen ion concentration
or activity present in a given solution.  pH numbers are the
negative  logarithm of the hydrogen ion concentration.  A pH
of 7 indicates neutrality or a balance between free hydrogen
and free  hydroxyl  ions.   Solutions  with  a  pH  above  7
indicate  that  the solution is alkaline, while a pH below 7
indicates that the solution is acidic.  Knowledge of the  pH
of  water  or  wastewater is useful in determining necessary
measures  for  corrosion  control,  pollution  control,  and
disinfection.   Waters  with a pH below 6.0 are corrosive to
water works structures, distribution  lines,,  and  household
plumbing  fixtures  such as iron, copper, zinc, cadmium, and
lead.  Low pH waters not only tend to dissolve  metals  from
structures and fixtures but also tend to redissolve or leach
metals  from sludges and bottom sediments.  The hydrogen ion
concentration can affect the "taste" of the water and  at  a
low pH, water tastes "sour."

Extremes  of  pH  or  rapid  pH  changes  can  exert  stress
conditions or kill aquatic  life  outright.   Even  moderate
changes   from   "acceptable"  criteria  limits  of  pH  are
deleterious to  some  species.   The  relative  toxicity  to
aquatic  life  of  many materials is increased by changes in
the water pH.   For  example,  metalocyanide  complexes  can
increase  a  thousand-fold in toxicity with a drop of 1.5 pH
units.  Similarly, the toxicity of ammonia is a function  of
pH.   The  bactericidal  effect of chlorine in most cases is
less  as  the  pH  increases,   and   it   is   economically
advantageous to keep the pH close to 7.

Most bacteria (and other protists) that are essential to the
operation  of  a  biological treatment system cannot bear pH
levels above 9.5 or below 5.0.  The  pH  range  for  optimum
growth  generally lies between 6.5 to 7.5.  Depending on the
volume of a particular waste and the acidity  or  alkalinity
of  the  waste  in  the treatment unit, an incoming waste of
extreme pH could have a substantially adverse  effect  on  a
treatment unit.

Acidity.   Acidity is defined as the quantitative ability of
a  water  to  neutralize  hydroxyl  ions.   It  is   usually
expressed   as  the  calcium  carbonate  equivalent  of  the
                            36

-------
hydroxyl ions neutralized.  Acidity should not  be  confused
with  pH  value.   Acidity  is the quantity of hydrogen ions
which may be released to react with or  neutralize  hydroxyl
ions  while  pH  is a measure of the free hydrogen ions in a
solution at the instant  the  pH  measurement  is  made.   A
property  of  many  chemicals,  called  buffering,  may hold
hydrogen ions in solution from being in the free  state  and
being  measured  as  pH,  The bond of most buffers is rather
weak and hydrogen ions tend to be released from  the  buffer
as needed to maintain a fixed pH value.

Highly  acid  waters  are corrosive to metals, concrete, and
living organisms, exhibiting the pollutional characteristics
outlined above for low pH waters.   Depending  on  buffering
capacity, water may have a higher total acidity at pH values
of 6.0 than other waters with a pH value of 4.0.

Highly  acid wastes can exhibit the same detrimental effects
on microorganisms as wastes of low pH.  The  acidity  of  an
incoming waste is particularly important in the operation of
anaerobic  digesters,  where the pH for optimum operation is
6.6 to 7.6  An incoming waste of high  acidity  that  causes
the  pH  of  an  anaerobic  system  to  drop  below 6.2 will
severely upset the operation of the unit.   Wastes  of  high
acidity  are  also corrosive to the metals and concrete that
make up the structure of any treatment unit.

Alkalinity.  Alkalinity is defined as the ability of a water
to neutralize hydrogen ions.  It is usually expressed as the
calcium  carbonate   equivalent   of   the   hydrogen   ions
neutralized.

Alkalinity is commonly caused by the presence of carbonates,
bicarbonates,  hydroxides,  and  to a lesser extent borates,
silicates, phophates, and organic  substances.   Because  of
the  nature  of  the  chemicals  causing alkalinity, and the
buffering capacity of carbon dioxide in water, very high  pH
values are seldom found in natural waters.

Excess alkalinity, as exhibited in a high pH value, may make
water  corrosive  to  certain  metals,  detrimental  to most
natural organic materials, and toxic to living organisms.

Ammonia is more irritating at higher pH.   The lacrimal fluid
of the human eye  has  a  pH  of  approximately  7.0  and  a
deviation  of  0.1  pH  unit from the norm may result in eye
irritation for the  swimmer.   Appreciable  irritation  will
cause severe pain.

A  waste of high alkalinity can interfere with the operation
of a treatment unit,  causing the death of microorganisms and
the corrosion of structural materials.
                            87

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Oil and Grease

Because of widespread use, oil and grease  occurs  often  in
wastewater  streams.  These oily wastes may be classified as
follows:

    °    Light Hydrocarbons.   These include light fuels such
         as  gasoline,   kerosene,   and   jet   fuel,   and
         miscellaneous    solvents   used   for   industrial
         processing, degreasing, or cleaning purposes.   The
         presence of these hydrocarbons may make the removal
         of other heavier oily wastes more difficult.

    °    Heavy Hydrocarbons,  Fuels, and Tars.  These include
         the crude oils, diesel oils, #6 fuel oil,  residual
         oils,  shop  oils,  and  in some cases, asphalt and
         road tar.

    o    Lubricants and  Cutting  Fluids.   These  generally
         fall  into  two classes: non-emulsifiable oils such
         as lubricating oils and greases,  and  emulsifiable
         oils  such  as  water  soluble  oils, rolling oils,
         cutting oils, and drawing compounds.   Emulsifiable
         oils   may  contain  fat,  soap  or  various  other
         additives.

These compounds can settle or float and may exist as  solids
or  liquids  depending  upon  factors such as method of use,
production process, and temperature of wastewater.

Oil and grease even in small quantities  causes  troublesome
taste  and  odor problems.  Scum lines from these agents are
formed on water treatment basin walls and other  containers.
Fish  and  waterfowl are adversely affected by oils in their
habitat.  Oil emulsions may adhere  to  the  gills  of  fish
causing  suffocation,  and the flesh of fish is tainted when
microorganisms that were exposed to  waste  oil  are  eaten.
Deposition of oil in the bottom sediments of water can serve
to inhibit normal benthic growth.  Oil and grease exhibit an
oxygen demand.

Levels  of  oil  and  grease  which  are  toxic  to  aquatic
organisms vary  greatly,  depending  on  the  type  and  the
species  susceptibility.  However, it has been reported that
crude oil in concentrations as low as 0.3 mg/1 is  extremely
toxic  to  freshwater  fish.    It  has been recommended that
public water supply sources be essentially free from oil and
grease.

Oil and grease in quantities of 100 1/sq km   (10  gallons/sq
mile)  show up as a sheen on the surface of a body of water.
The presence  of  oil  slicks  prevent  the  full  aesthetic
                            88

-------
enjoyment  of  water.  The presence of oil in water can also
increase the toxicity of other substances  being  discharged
into the receiving bodies of water.

Oil and grease can cause problems with scum formation in wet
wells  and  clarifiers.  Mineral oils in particular can coat
solid particles that are present in wastes.   The  particles
hinder   biological^   activity   and   increase  maintenance
problems.  Free oil  (as measured  by  CC14  extraction)  has
reportedly  interfered  with aerobic biological treatment at
concentrations of 50 to 100 mg/1 (15).

Oxygen Demand (BOD and COD)

Organic and some inorganic compounds  can  cause  an  oxygen
demand   to  be  exerted  in  a  receiving  body  of  water.
Indigenous microorganisms utilize the organic wastes  as  an
energy  source  and oxidize the organic matter.  In doing so
their  natural  respiratory  activity   will   utilize   the
dissolved oxygen.

Biochemical  oxygen  demand  (BOD).   BOD is the quantity of
oxygen required for the biological and chemical oxidation of
waterborne substances  under  ambient  or  test  conditions.
Materials   which   may   contribute  to  the  BOD  include:
carbonaceous organic materials usable as a  food  source  by
aerobic   organisms;   oxidizable   nitrogen   derived  from
nitrites, ammonia and organic nitrogen compounds which serve
as  food  for  specific  bacteria,  and  certain  chemically
oxidizable   materials   such  as  ferrous  iron,  sulfides,
sulfite, etc.  which will react with dissolved oxygen or are
metabolized by bacteria.  In most industrial  and  municipal
wastewaters,   the  BOD  derives  principally  from  organic
materials and from ammonia (which  is  itself  derived  from
animal or vegetable matter).

The  BOD  of  a  waste  exerts  an  adverse  effect upon the
dissolved oxygen resources of a body of  water  by  reducing
the  oxygen available to fish, plant life, and other aquatic
species.   Conditions  can  be  reached  where  all  of  the
dissolved  oxygen  in  the  water  is utilized, resulting in
anaerobic conditions and the production of undesirable gases
such as hydrogen sulfide  and  methane.   The  reduction  of
dissolved  oxygen  can  be  detrimental to fish populations,
fish growth rate, and organisms used as fish food.  A  total
lack  of  oxygen due to the exertion of an excessive BOD can
result in the death of all aerobic  aquatic  inhabitants  in
the affected area.

Water  with a high BOD indicates the presence of decomposing
organic matter  and  an  associated  increase  in  bacterial
concentrations  that degrade its quality and potential uses.
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A by-product of high BOD  concentrations  can  be  increased
algal   concentrations   and   blooms   which   result  from
decomposition of the organic matter and which form the basis
of algal populations.

The BOD5_ (5-day BOD) test is used  widely  to  estimate  the
pollutional  strength  of  domestic and industrial wastes in
terms of the oxygen that they  will  require  if  discharged
into  receiving  streams.   The  test is an important one in
water pollution control activities,, to evaluate  the  design
and  efficiencies  of  wastewater  treatment  works,  and to
indicate the state of purification or pollution of receiving
bodies of water.

Complete biochemical oxidation of a given waste may  require
a  period  of  incubation  too long for practical analytical
test purposes.   For this reaison, the  five  day  period  has
been  accepted  as  standard, and the test results have been
designated as BODJ5.  Specific chemical test methods are  not
readily   available  for  measuring  the  quantity  of  many
degradable substances and their reaction products.  Reliance
in such cases is placed on the  collective  parameter,  BODj>
which  measures  the  weight of dissolved oxygen utilized by
microorganisms  as  they  oxidize  or  transform  the  gross
mixture  of  chemical  compounds  in  the  wastewater.   The
biochemical reactions involved in the  oxidation  of  carbon
compounds  are  related  to  the  period of incubation.  The
five-day BOD normally measures only 60 to 80 percent of  the
carbonaceous  biochemical  oxygen  demand of the sample, and
for many purposes this is a reasonable parameter.

Additionally, it can be used to estimate the gross  quantity
of oxidizable organic matter.

The  BODS^  test  is  essentia.lly  a bioassay procedure which
provides   an   estimate   of   the   oxygen   consumed   by
microorganisms  utilizing the degradable matter present in a
waste under conditions that are representative of those that
are likely to occur in nature.  Standard conditions of time,
temperature, suggested microbial seed,  and  dilution  water
for the wastes have been defined and are incorporated in the
standard  analytical  procedure.   Through  the  use of this
procedure, the  oxygen  demand  of  diverse  wastes  can  be
compared  and  evaluated for pollution potential and to some
extent for treatability by biological treatment processes.

Because  the  BOD  test  is  a  bioassay  procedure,  it  is
important  that  the environmental conditions of the test be
suitable  for  the  microorganisms   to   function   in   an
uninhibited  manner  at  all  times.   This means that toxic
substances must be absent and that the necessary  nutrients,
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such  as  nitrogen, phosphorous, and trace elements, must be
present.

Chemical Oxygen Demand (COD).   COD  is  a  purely  chemical
oxidation  test devised as an alternate method of estimating
the total oxygen demand of a wastewater.  Since  the  method
relies   on   the  oxidation-reduction  system  of  chemical
analyses rather than  on  biological  factors,  it  is  more
precise,  accurate,  and  rapid  than the BOD test.  The COD
test is widely used to  estimate  the  total  oxygen  demand
(ultimate rather than 5-day BOD) to oxidize the compounds in
wastewater.  It is based on the fact that organic compounds,
with  a  few  exceptions, can be oxidized by strong chemical
oxidizing agents under acid conditions with  the  assistance
of certain inorganic catalysts.

The  COD  test  measures the oxygen demand of compounds that
are biologically  degradable  and  of  many  that  are  not.
Pollutants  which  are  measured  by  the  BOD5_ test will be
measured by the COD test.  In addition, pollutants which are
more resistant to biological oxidation will also be measured
as COD.  COD is a more inclusive measure  of  oxygen  demand
than  is BODJ3 and will result in higher oxygen demand values
than will the BOD5> test.

The  compounds  which  are  more  resistant  to   biological
oxidation  are  becoming  of greater and greater concern not
only because of their slow but continuing oxygen  demand  on
the  resources  of  the receiving water, but also because of
their potential health effects on aquatic life and humans.

Many of these compounds result  from  industrial  discharges
and some have now been found to have carcinogenic, mutagenic
and   similar   adverse   effects,   either   singly  or  in
combination.  Concern about these compounds has increased as
a result of demonstrations that their long life in receiving
waters - the result of a slow biochemical oxidation  rate
allows  them  to  contaminate downstream water intakes.  The
commonly  used  systems  of  water  purification   are   not
effective   in   removing   these  types  of  materials  and
disinfection such as chlorination may convert them into even
more hazardous materials.

Thus, the COD test measures organic matter which  exerts  an
oxygen demand and which may affect the health of people.  It
is   a   useful   analytical   tool  for  pollution  control
activities.  It provides a more  rapid  measurement  of  the
oxygen demand and an estimate of organic compounds which are
not measured in the BODS test.

Total Suspended Solids (TSS)
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Suspended   solids   include   both  organic  and  inorganic
materials.  The inorganic compounds include sand, silt,   and
clay.   The  organic  fraction  includes  such  materials as
grease, oil, tar, and animal and vegetable  waste  products.
These  solids may settle out rapidly and bottom deposits are
often a  mixture  of  both  organic  and  inorganic  solids.
Solids may be suspended in water for a time, and then settle
to  the  bed of the stream or lake.  These solids discharged
with  man's  waste  may  be  inert,   slowly   biodegradable
materials,  or  rapidly  decomposable  substances.  While in
suspension, they increase the turbidity of the water, reduce
light penetration and impair the photosynesthic  activity  of
aquatic plants.

Chromium  (Cr
Chromium  is  an elemental metal usually found as a chromite
(FeCr20jJ).   The metal is normally processed by reducing  the
oxide with aluminum.

Chromium  and  its compounds are used extensively throughout
industry.   It is used to harden steel and as  an  ingredient
in  other  useful  alloys.   Chromium  is  also  used in the
electroplating  industry  as  an  ornamental  and  corrosion
resistant  plating  on steel and can be used in pigments and
as a pickling acid  (chromic acid) ,

The two most prevalent  chromium  forms  found  in  industry
wastewaters  are hexavalent and trivalent chromium.  Chromic
acid used in industry  is  a  hexavalent  chromium  compound
which is partially reduced to the trivalent form during use.
Chromium   can  exist  as  either  trivalent  or  hexavalent
compounds in raw  waste  streams,  but  hexavalent  chromium
predominates   at  the  conditions  found  in  most  wastes.
Hexavalent chromium  treatment  involves  reduction  to  the
trivalent  form  prior to removal of chromium from the waste
stream as a hydroxide precipitate.

Chromium,  in its various valence  states,  is  hazardous  to
man.   It  can  produce lung tumors when inhaled and induces
skin  sensitizations.   Large  doses   of   chromates   have
corrosive  effects  on  the  intestinal  tract and can cause
inflammation of the kidneys.  Levels of chromate  ions  that
have  no  effect  on  man appear to be so low as to prohibit
determination to date.  The recommendation for public  water
supplies  is  that  such  supplies contain no more than 0.05
mg/1 total chromium.

The toxicity of chromium salts to  fish  and  other  aquatic
life  varies  widely  with  the  species,  temperature,  pH,
valence of the chromium,  and  synergistic  or  antagonistic
effects,  especially that of hard water.  Studies have shown
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that trivalent chromium is more toxic to fish of some  types
than hexavalent chromium.  other studies have shown opposite
effects.   Fish  food  organisms  and  other  lower forms of
aquatic life are extremely sensitive to chromium and it also
inhibits the growth of algae.   Therefore,  both  hexavalent
and   trivalent  chromium  must  be  considered  harmful  to
particular fish or organisms.

Hexavalent chromium has been shown  to  interfere  with  the
operation   of   activated   sludge  systems  and  anaerobic
digesters  (22) and nitrification units  (15).  Slug doses  of
hexavalent  chromium of 500 mg/1 to activated sludge systems
have been shown to  reduce  BOD  removal  efficiency  by  11
percent  and  COD  removal  efficiency  by  13 percent,  for
periods as long as 32 hours.  Slug  doses  of  300  mg/1  to
anaerobic  digesters have caused gas production to cease for
seven days, and doses of 500 mg/1 have ceased gas production
permanently.  The nitrification process is severely affected
at Cr+6 concentrations in raw sewage on the order of 2  mg/1
to  5  mg/1.  The effects on these systems can be multiplied
by the presence of iron, copper,  and  high  acidity,  since
these  constituents  exert synergistic effects with chromium
(16).

Depending on the influent concentration, significant amounts
of Cr+6 can  pass  through  activated  sludge  systems;  the
removal  efficiency  has  been  reported  to be as low as 17
percent at influent Cr+6 concentrations of 50.0 mg/1, but as
high as 78 percent at concentrations of 0.5 mg/1 (22).

Copper (Cu)
Copper is an elemental metal that is sometimes found free in
nature and is  found  in  many  minerals  such  as  cuprite,
malachite,  azurite,  chalcopyrite,  and bornite.  Copper is
obtained  from  these  ores  by  smelting,   leaching,   and
electrolysis.    Significant  industrial  uses  are  in  the
plating,  electrical,  plumbing,   and   heating   equipment
industries.    Copper  is  also  commonly  used  with  other
minerals as an insecticide and fungicide.

Traces of copper are found in all forms of plant and  animal
life,  and  it  is an essential trace element for nutrition.
Copper is not considered to be a cumulative systemic  poison
for humans as it is readily excreted by the body, but it can
cause   symptoms   of   gastroenteritis,   with  nausea  and
intestinal irritations,  at  relatively  low  dosages.   The
limiting   factor  in  domestic  water  supplies  is  taste.
Threshold  concentrations  for  taste  have  been  generally
reported  in  the  range  of 1.0 to 2.0 mg/1 of copper while
concentrations of 5 to 7.5 mg/1 have made  water  completely
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undrinkable.   It  has  been  recommended that the copper in
public water supply sources not exceed 1 mg/1.

Copper salts cause undersirable color reactions in the  food
industry  and  cause  pitting  when  deposited on some other
metals such as aluminum and galvanized steel.   The  textile
industry  is affected when copper salts are present in water
used  for  processing   of   fabrics.    Irrigation   waters
containing  more  than  minute  quantities  of copper can be
detrimental to certain crops.  The  toxicity  of  copper  to
aquatic  organisms  varies  significantly, not only with the
species,  but  also   with   the   physical   and   chemical
'characteristics   of   the   water,  including  temperature,
hardness, turbidity, and carbon dioxide  content.   In  hard
water,  the  toxicity  of copper salts may be reduced by the
precipitation  of  copper  carbonate  or   other   insoluble
compounds.   The  sulfates  of copper and zinc and of copper
and cadmium are synergistic in their toxic effect on fish.

Copper concentrations less than 1 mg/1 have been reported to
be toxic, particularly in soft water, to many kinds of fish,
crustaceans,    mollusks,    insects,    phytoplankon    and
zooplankton.   Concentrations  of  copper,  for example, are
detrimental  to  some  oysters;  above  0.1  mg/1.   Oysters,
cultured  in seawater containing 0.13 to 0.5 mg/1 of copper,
deposit the metal in their bodies and become unfit as a food
substance.

The toxic effects of  copper  are  compounded  when  certain
other  metals  are  present.   Copper  and  zinc  have  been
reported to be five times as toxic when combined than  would
be   expected   considering   the  toxicity  of  each  metal
separately.  Increased toxicological effects  of  a  similar
magnitude  have  been  noted between copper and cadmium, and
other synergistic toxic effects of copper have been observed
when  mercury  or  phosphates  are   present.    conversely,
sulfide,  high  pH,  and  certciin  chelating agents  (such as
EDTA) have been reported  to  be  antagonistic  with  copper
 (16).

Copper, as well as most metals, is generally not susceptable
to  treatment  by  biological  treatment  processes at POTW.
Research has shown that up to half of the input  metal  will
pass  through  the  treatment  plant,  with  about  30 to 50
percent  of  the  copper  which  passes  through  the  plant
appearing in the soluble state.  Digestion has been impaired
by  copper  continuously  fed  at 10 mg/1, and slug doses of
copper at 50 mg/1 for four hours in an  unacclimated  system
have resulted in greatly decreased efficiencies of treatment
plants for up to 100 hours.

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The  copper  that is removed from the influent stream by the
POTW is absorbed on the sludge, or it appears in the  sludge
as the hydroxide of the metal.  Experimental data shows that
when  dried  sludge is spread over tillable land, the copper
tends to remain in place  down  to  the  depth  of  tillage,
except  for  that copper that is taken up by plants grown in
the soil.  Copper tends  to  concentrate  in  the  roots  of
plants,  and  has  shown little tendency to migrate to other
parts of the plant.  In most  cases,  the  concentration  of
copper in plants will kill the plant before it has reached a
high  enough  concentration to evidence harm in animals that
may eat the plants, although  it  is  reported  that  copper
concentrated  in  plants  has  resulted  in fatalities among
sheep.

Cyanide  (CM)

Cyanide is a  compound  that  is  widely  used  in  industry
primarily  as  sodium  cyanide  (NaCN)  or  hydrocyanic acid
 (HCN).  The major use of cyanides is in  the  electroplating
industry  where  cyanide baths are used to hold ions such as
zinc and cadmium in solution.  Cyanides in various compounds
are also used in steel plants, chemical plants, photographic
processing, textile dying, and ore processing.

Of all the cyanides, hydrogen cyanide (HCN)  is probably  the
most  acutely  lethal compound.  HCN dissociates in water to
hydrogen ions and cyanide ions in a pH  dependent  reaction.
The  cyanide  ion  is  less  acutely  lethal  than HCN.  The
relationship of pH to HCN shows that as the pH is lowered to
below seven there is less than one percent  of  the  cyanide
molecules  in the form of the CN ion and the rest is present
as HCN.  When the pH is increased  to  8,  9,  and  10,  the
percentage  of  cyanide present as CN ion is 6.7, 42, and 87
percent, respectively.  The toxicity  of  cyanides  is  also
increased  by  increases  in  temperature.    A.  rise of 10°C
produced a two-to threefold increase  in  the  rate  of  the
lethal action of cyanide.

In the body, the CN ion, except for a small portion exhaled,
is  rapidly  changed  into  a  relatively  non-toxic complex
 (thiocyanate)  in the liver  and  eliminated  in  the  urine.
There  is no evidence that the CN ion is stored in the body.
The safe ingested limit of cyanide has been estimated to  be
something  less  than  18  mg/day,  part of which comes from
normal environment and  industrial  exposure.    The  average
fatal  dose  of  HCN by ingestion by man is 50 to 60 mg.  It
has been recommended that a limit of 0. 2 mg/1 cyanide not be
exceeded in public water supply sources.

The harmful effects of  the  cyanides  on  aquatic  life  is
affected  by  the pH,  temperature, dissolved oxygen content.
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and  the  concentration  of  minerals  in  the  water.   The
biochemical  degradation  of  cyanide  is  not  affected  by
temperature in the range of 10°C to 35° C while the  toxicity
of HCN is increased at higher temperatures.

On  lower forms of life and organisms, cyanide does not seem
to be as toxic as it is toward  fish.   The  organisms  that
digest  BOD  were  found to be inhibited at 60 mg/1 although
the effect is more one of delay  in  exertion  of  BOD  than
total reduction.

Certain  metals  such  as  nickel  may  form  complexes with
cyanide to reduce lethality, especially at higher pH values.
On the other hand, zinc and cadmium cyanide complexes may be
exceedingly toxic.

Research has shown that concentrations of 1.0 to 2.0 mg/1 of
cyanide  (as HCN) in influent,  sewage  adversely  affect  the
performance   of   activated   sludge  units  and  anaerobic
digesters,  and   2.0   mg/1   of   cyanide   inhibits   the
nitrification  process.  The  quality  of  trickling  filter
effluent has  been  reported  to  be  severely  affected  at
influent cyanide concentrations of 30 mg/1 (15).

Iron  (Fe)

Iron  is  an abundant metal found in the earth's crust.  The
most common iron ore is hematite from which iron is obtained
by reduction with carbon.  Other forms  of  commercial  ores
are magnetite and taconite.  Pure iron is not often found in
commercial  use, but it is usually alloyed with other metals
and minerals, the most common being carbon.

Iron is the basic element in the  production  of  steel  and
steel alloys.  Iron with carbon is used for casting of major
parts  of machines and it can be machined, cast, formed, and
welded.  Ferrous iron is used in paints, while powdered iron
can  be  sintered  and  used  in  powder  metallurgy.   Iron
compounds  are  also  used  to  precipitate other metals and
undesirable minerals from industrial wastewater streams.

Iron is chemically reactive  and  corrodes  rapidly  in  the
presence  of  moist  air  and  at elevated temperatures.  In
water and in the presence of oxygen, the resulting  products
of  iron  corrosion  may  be  pollutants  in water.  Natural
pollution occurs from the leaching  of  soluble  iron  salts
from   soil   and  rocks  and  is  increased  by  industrial
wastewater  from  pickling   baths   and   other   solutions
containing iron salts.

Corrosion  products  of  iron  in  water  cause  staining of
porcelain fixtures, and ferric iron combines with tannin  to
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produce a dark violet color.  The presence of excessive iron
in  water  discourages  cows from drinking and, thus reduces
milk production.  High concentrations of ferric and  ferrous
irons  in  water  kill  most fish introduced to the solution
within a few hours.  The killing  action  is  attributed  to
coatings of iron hydroxide precipitates on the gills.  Iron-
oxidizing  bacteria  are  dependent  on  iron  in  water for
growth.  These bacteria form  slimes  that  can  affect  the
aesthetic  values  of  bodies of water and cause stoppage of
flows in pipes.

Iron is an essential  nutrient  and  micronutrient  for  all
forms of growth.  Drinking water standards in the U.S.   have
set  a  recommended  limit  of  0.3 mg/1 of iron in domestic
water supplies based not  on  physiological  considerations,
but rather on aesthetic and taste considerations.

Iron has no effect on the activated sludge process except at
very  high  concentrations  (on the order of 1000 mg/1).  The
effect of iron on the  sludge  digestion  process  has  been
reported  to  be  much greater - iron levels above 5 mg/1 in
digesters have caused interference with the process, due  to
the  release  of acidity when the iron is hydrolyzed.  These
effects may  be  magnified  by  the  synergistic  effect  of
chromium  on  iron, or decreased by the antagonistic effects
of sulfide, cyanide, and high pH on irons (16).

Nickel (Ni)

Elemental nickel is seldom  found  in  nature  in  the  pure
state.  Nickel is obtained commercially from pentlendite and
pyrrhotite.   It  is  a  relatively plentiful element and is
widely distributed throughout the earth's crust.  It  occurs
in  marine  organisms and is found in the oceans.  Depending
on the dose, the organism involved, and the type of compound
involved, nickel may be beneficial or toxic.  Pure nickel is
not soluble in water but many of its salts are very soluble.

The toxicity of nickel to man is believed to be very low and
systemic poisoning of human beings by nickel or nickel salts
is almost unknown.  Nickel salts have caused the  inhibition
of  the biochemical oxidation of sewage.  They also caused a
50  percent  reduction  in  the  oxygen   utilization   from
synthetic  sewage  in  concentrations  of  3.6 to 27 mg/1 of
various nickel salts.

Nickel is extremely toxic to citrus plants.   It is found  in
many  soils  in California, generally in insoluble form, but
excessive acidification of such soil may render it  soluble,
causing  severe  injury  to  or  the  death of plants.   Many
experiments with plants in solution cultures have shown that
nickel at 0.5 to 1.0 mg/1 is inhibitory to growth.
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Nickel salts can  kill  fish  at  very  low  concentrations.
However,  it  has  been  found to be less toxic to some fish
than copper, zinc, and iron,.  Data for  the  fathead  minnow
show  death occurring in the range of 5 to 13 mg/1 depending
on the alkalinity of the water.

Nickel  is  present  in  coastal   and   open   ocean   with
concentrations in the range of 0.1 to 6.0 mg/1, although the
most  common values are 2 to 3 mg/1.  Marine animals contain
up to 400 mg/1, and marine plants contain up to 3,000  mg/1.
The  lethal  limit  of  nickel  to some marine fish has been
reported as low as 0.8 ppm.   Concentrations  of  13.1  mg/1
have  been  reported  to cause a 50 percent reduction of the
photosynthetic  activity  in  the  giant  kelp  (Macrocystic
pyrifera)   in 96 hours, and a low concentration was found to
kill oyster eggs.

Nickel can inhibit the operation of activated  sludge  units
and  nitrification  units.  Up to a five percent decrease in
the BOD removal efficiency of.  activated  sludge  units  has
been  reported  at  nickel influent concentrations of 2.5 to
10.0 mg/1. Slug doses of nickel of  200  mg/1  to  activated
sludge   units   have  been  reported  to  seriously  reduce
treatment  efficiency  (22).   Severe  inhibition   of   the
nitrification  process  has been reported at nickel influent
concentrations of 0.5 mg/1  (15).

Significant amounts of nickel  can  pass  through  treatment
units - the activated sludge process has been reported to be
only  approximately  30  percent efficient in the removal of
nickel.

Phosphorus  (P)

Phosphorus occurs in natural waters and  in  wastewaters  in
the  form  of  various types of phosphates.  These forms are
commonly   classified   into   orthophosphates,    condensed
phosphates    (pyro-,   meta-,   and   polyphosphorus),   and
originally bound phosphates.  These may occur in the soluble
form, in particles of detritus, or in the bodies of  aquatic
organisms.

The   various  forms  of  phosphates  find  their  way  into
wastewaters from a variety of industrial,  residential,  and
commercial  sources.   Small  amounts  of  certain condensed
phosphates are added to some water supplies in the course of
potable water  treatment.   Large  quantities  of  the  same
compounds may be added when the water is used for laundering
or   other   cleaning   since   these  materials  are  major
constituents  of  many  commercial  cleaning   preparations.
Phosphate  coating  of  metals  is  another  major source of
phosphates in certain industrial effluents.
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The increasing problem of the growth of algae in streams and
lakes appears to be associated with the increasing  presence
of   certain  dissolved  nutrients,  chief  among  which  is
phosphorus.  Phosphorus is an element which is essential  to
the  growth  of  organisms  and it can often be the nutrient
that limits the aquatic growth that  a  body  of  water  can
support.  In instances where phosphorus is a growth limiting
nutrient, the discharge of sewage, agricultural drainage, or
certain industrial wastes to a receiving water may stimulate
the   growth,  in  nuisance  quantities,  of  photosynthetic
aquatic microorganisms and macroorganisms.

The increase in  organic  matter  production  by  algae  and
plants in a lake undergoing eutrophication has ramifications
throughout  the aquatic ecosystem.  Greater demand is placed
on the dissolved oxygen in the water as the  organic  matter
decomposes  at  the termination of the life cycles.  Because
of this process, the deeper waters of the  lake  may  become
entirely   depleted   of  oxygen,  thereby  destroying  fish
habitats  and  leading  to  the  elimination  of   desirable
species.   The  settling  of  particulate  matter  from  the
productive upper layers changes the character of the  bottom
mud,  also  leading to the replacement of certain species by
less desirable organisms.  Of great importance is  the  fact
that  nutrients  inadvertently introduced to a lake are, for
the most part, trapped there  and  recycled  in  accelerated
biological  processes.   Consequently,  the damage done to a
lake in  a  relatively  short  time  requires  a  many  fold
increase in time for recovery of the lake.

When  a  plant  population  is  stimulated in production and
attains a nuisance status,  a  large  number  of  associated
liabilities  are immediately apparent.  Dense populations of
pond weeds  make  swimming  dangerous.   Boating  and  water
skiing  and  sometimes  fishing may be eliminated because of
the mass of vegetation that serves as a physical  impediment
to  such activities.  Plant populations have been associated
with stunted fish populations and with poor  fishing.  Plant
nuisances  emit  vile  stenches,  impart tastes and odors to
water supplies, reduce  the  efficiency  of  industrial  and
municipal  water  treatment, impair aesthetic beauty, reduce
or restrict resort trade, lower waterfront property  values,
cause  skin rashes to man during water contact, and serve as
a desired substrate and breeding ground for flies.

Phosphorus in the elemental form is particularly toxic,  and
subject  to bioaccumulation in much the same way as mercury.
Colloidal  elemental  phosphorus  will  poison  marine  fish
(causing  skin  tissue  breakdown and discoloration).  Also,
phosphorus  is  capable  of  being  concentrated  and   will
accumulate  in  organs  and  soft tissues.  Experiments have
                            99

-------
shown that marine  fish  will  concentrate  phosphorus  from
water containing as little as 1 ug/1.

Zinc (Zn)

Occurring  abundantly  in  rocks  and  ores, zinc is readily
refined into a stable pure metal and is used extensively for
galvanizing, in alloys, for electrical purposes, in printing
plates, for dye manufacture and for  dyeing  processes,  and
for  many other industrial purposes.  Zinc salts are used in
paint   pigments,    cosmetics,    Pharmaceuticals,    dyes,
insecticides,  and  other  products  too  numerous  to  list
herein.  Many of these salts (e.g., zinc chloride  and  zinc
sulfate)   are  highly  soluble  in  water; hence it is to be
expected that zinc might occur in  many  industrial  wastes.
On  the  other  hand,  some zinc salts  (zinc carbonate, zinc
oxide,  zinc sulfide)  are insoluble in water and consequently
it is to be expected that some zinc will precipitate and  be
removed readily in most natural waters.

In  zinc  mining  areas,  zinc  has  been found in waters in
concentrations as high as 50 mg/1  and,  in  effluents  from
metal-plating works and small-arms ammunition plants, it may
occur  in  significant  concentrations.  In most surface and
ground waters, it is present only in trace  amounts.   There
is  some  evidence that zinc irons are adsorbed strongly and
permanently on silt, resulting in inactivation of the zinc.

Concentrations of zinc in excess of 5 mg/1 in raw water used
for drinking water supplies cause an undesirable taste which
persists through conventional treatment.  Zinc can  have  an
adverse effect on man and animals at high concentrations.

In  soft  water,  concentrations of zinc ranging from 0.1 to
1.0 mg/1 have been reported to be lethal to fish.   Zinc  is
thought  to  exert  its  toxic  action  by forming insoluble
compounds with the mucous thai: covers the gillss,  by  damage
to the gill epithelium, or possibly by acting as an internal
poison.   The  sensitivity  of  fish  to  zinc  varies  with
species, age and condition, as well as with the physical and
chemical characteristics of the water.  Some acclimatization
to the presence of zinc  is  possible.   It  has  also  been
observed  that  the effects of zinc poisoning may not become
apparent  immediately,  so  that  fish  removed  from  zinc-
contaminated  to  zinc-free  water   (after  4  to 6 hours of
exposure to zinc) may die 48 hours later.  The  presence  of
copper in water may increase the toxicity of zinc to aquatic
organisms,  but  the  presence  of  calcium  or hardness may
decrease the relative toxicity.

Observed values for the distribution of zinc in ocean waters
vary widely.  The  major  concevrn  with  zinc  compounds  in
                            100

-------
marine  waters  is  not one of acute toxicity, but rather of
the long-term sublethal effects of  the  metallic  compounds
and  complexes.   From  an  acute  toxicity  point  of view,
invertebrate marine animals seem to be  the  most  sensitive
organisms  tested.   The  growth  of  the  sea  urchin,  for
example, has been retarded by as little as 30 ug/1 of zinc.

Zinc is readily taken up  and  translocated  within  plants.
The  activity  of  zinc  is  most profound in acid soils and
decreases in the presence of large amounts of phosphates, as
would be found in sludges from POTW.  For each unit increase
in the pH, there is a hundredfold decrease in  the  toxicity
of   zinc.   In  plants  the  poisoning  mechanism  is  iron
deficiency, and to avoid this, lime must  be  added  to  the
soil  to  maintain  soil pH above 6.0.  Generally, zinc will
kill the plants before reaching  concentrations  harmful  to
animals in the plants.

Dissolved  zinc is generally not susceptible to treatment by
biological treatment processes at POTW.  In slug doses,  and
particularly  in  the presence of copper, dissolved zinc can
interfere with or seriously disrupt the  operation  of  POTW
using  biological  processes  by  reducing  overall  removal
efficiencies, largely as a result of  the  toxicity  of  the
metal to biological organisms.  However, zinc solids (in the
form  of  hydroxides or sulfides)  do not appear to interfere
with  biological  treatment  processes  on  the   basis   of
available data.  Such solids accumulate in the sludge, where
subsequent effects depend on the sludge disposal method.

Polychlorinated Biphenyls (PCBs)

Polychlorinated  biphenyls  (PCBs)  are a family of partially
or wholly chlorinated isomers of biphenyl.   The  commercial
mixtures generally contain UO to 60 percent chlorine with as
many  as  50  different detectable isomers present.  The PCB
mixture  is  a  colorless  and  viscous  fluid,   relatively
insoluble   in   water,   that   can   withstand  very  high
temperatures without  degradation.    PCB's  do  not  conduct
electricity, and the more highly chlorinated isomers are not
readily degraded in the environment.

PCBs  are used in paints, inks, and plastics.   They are also
found in hydraulic systems,  in transformers and  capacitors,
and in the wastes from the reprocessing of certain papers.

The  major  uses  of  PCBs  can  be grouped into three major
categories: open uses, partially  closed  system  uses,  and
closed  system  uses.    Open  uses  include  paints,  inks,
plastics, and paper coatings.   The  PCBs  in  all  of  these
products contact with the environment and can be leached out
by  water.   The  so-called carbonless carbon paper contains
                            101

-------
PCBs  in  the  encapsulated  ink  and  is  claimed   to   be
responsible  for  the  PCBs  found  extensively  in recycled
paper.  PCBs have been used  as  plasticizers  in  polyvinyl
chloride (PVC)  and chlorinated rubbers.

Uses of PCBs in partially closed systems include the working
fluid  in  heat  exchangers  and  hydraulic  systems.  These
systems have a potential for leakage of the PCB fluid either
during use or after being discarded.

The electric industry is the single major consumer  of  PCBs
mainly   in   a  closed  loop  system  in  transformers  and
capacitors.  PCBs are ideal for use  in  large  transformers
and power capcitors, since they are non-flammable and do not
conduct  electricity,  but  still  transfer  heat well.  The
fluid is generally sealed into the unit to prevent loss, but
leakage may occur from some transformers through gaskets  or
broken  oil level viewing glasses.  Release of PCBs into the
environment  may  also  occur  during   the   drainage   and
replacement  of  oil in defective transformers, or if old or
defective capacitors  are  disposed   of  in  landfills  and
broken  while  being  buried.   Transformers  and capacitors
account for about 63 percent of all PCB use.

Agreement is not universal on exactly how PCBs are  released
into  the  environment  or  in what quantities.  Analyses of
water samples from 30 major tributaries to the  Great  Lakes
indicate  widespread  contamination,  with 71 percent of all
samples having detectable concentrations  (greater  than  10
parts  per trillion).  PCBs have been found in all organisms
analyzed from the north and south Atlantic, even in  animals
living under 11,000 feet of water.  It is reported that one-
third  of  the  human  tissue  sampled  in the United States
contains more than one part ptvr million (ppm)  of PCBs.

Once in the environment, PCBs appear to persist for  a  long
time.   Evidence  for  this  can be seen in the fact that in
most areas of the continent and  through  out  the  Atlantic
Ocean more PCB than DDT is found in the animals, even though
three  times more DDT is produced each year and all of it is
discharged directly into the environment.  Based  on  present
available data, it seems safe to assume the PCBs are present
in  varying  concentrations  in every species of wildlife on
earth.

Liver damage is a common effect  of  PCBs  on  all  species,
while   the   occurrence   of   edema,   skin  lesions,  and
reproductive failure is species-specific.    Hatchability  of
eggs is noticeably decreased by exposure to PCBs.  PCBs have
been  shown  to produce lethal and sublethal effects on fish
and animals, including reduced reproduction of  the  species
and abnormal young.
                            102

-------
PCBs  may  be  removed  by  up  to  70  percent or more from
domestic  wastewaters  during  biological  treatment    (22).
However,  PCBs  appear  to  simply  accumulate  unchanged in
treatment tank sludges, and are not biodegraded or converted
to other more readily degradable substances during treatment
(23).  Disposal of treatment sludges in landfills could then
release PCBs into the environment once again.  There is some
evidence,  however,   that   PCBs   are   destroyed   during
incineration of sewage sludge (24).

Ethylenediamine Tetracetic Acid (EDTA)

No definitive information on the toxicity or treatability of
EDTA  in biological treatment systems is available to EPA at
the present time.
                            103

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                        SECTION VII

              TREATMENT AND CONTROL TECHNOLOGY
Introduction

Treatment and control technologies for potential  pollutants
discharged  from  steam  electric  power  generating  plants
discharging to publicly-owned  treatment  works  (POTW)   are
outlined  in  this  section.   In-process controls discussed
include those techniques which  are  normally  used  by  the
industry or by industries employing similar processes.  Such
controls    include    process    modifications,   materials
substitution, raw materials  and  products  recovery,  water
conservation   and   wastewater   reuse,  and  general  good
housekeeping practices.

Wastewater effluents discharged to publicly-owned  treatment
facilities  are sometimes treated by end-of-process physical
or chemical systems to remove  pollutants  which  can  upset
operation  of the POTW or which may be treated inadequately.
Such treatment methods are numerous, but they generally fall
into one of three broad categories in accordance with  their
process  objectives.   These  include pH control, removal of
dissolved materials, and separation of phases.

Of the twenty-three plants surveyed only eight provide  end-
of-pipe  treatment  to their waste, before discharging it to
POTW.  The extent of treatment applied varies in  accordance
with the local requirements for discharge limitations.  Most
of  the  plants  use retention ponds to equalize the flow to
POTWs.  These ponds also serve as sedimentation  basins  for
partial  removal of suspended solids by gravity settling and
are sometimes  equipped  with  skimming  devices  to  remove
floating   oil.    A  detailed  description  of  end-of-pipe
treatment techniques used is presented in Section V of  this
report.

END-OF-PIPE TREATMENT TECHNOLOGY

Treatment Technologies Available

If  a  pollutant  in  a  waste  stream is not acceptable for
discharge to the publicly-owned treatment plant, end-of-pipe
treatment must be provided to remove the pollutant or reduce
it  to  allowable  limits.   Only  a  few  existing   plants
discharging  into  POTW provide end-of-pipe treatment.  Yet,
basic technology is available to reduce nearly  all  of  the
pollutants  produced  by  steam  electric generating plants.
For certain pollutants, in-plant controls are  probably  the
preferred  control  strategy.   This  technology is shown in
                            105

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Tables  VII-1  and  VII-2.   Table  VII-1  lists   potential
dissolved  matter removal methods and Table VII-2 provides a
similar list of solid liquid separation processes.  Most  of
the  processes  listed  are  in  use  for treatment of steam
electric  or  other  industrial  or  municipal   water   and
wastewaters.

TREATMENT OF MAJOR POLLUTANTS

Available  technology  and  efficiency  of their removal for
major pollutants are shown in Table VII-3.  These are  based
on  data  obtained  from  several  different  industries who
discharge pollutants  similar  to  those  observed  in  this
industry.   The  following  is  a  brief  discussion  of the
technologies associated with removal of pollutants from  the
power plant.

Total  Dissolved  Solids.  Removal of total dissolved solids
(TDS) from wastewaters is one of the more difficult and more
expensive waste treatment procedures.  Where TDS result from
heavy metal or hardness ions, reduction can be  achieved  by
chemical  precipitation  methods;  however,  where dissolved
solids  are  present  as  sodium,  calcium,   or   potassium
compounds,  then  TDS  reduction  requires  more specialized
treatment,  such  as   reverse   osmosis,   electrodialysis,
distillation, and ion exchange.

Total  Suspended  Solids.   Suspended  solids removal can be
achieved  by  sedimentation   and   filtratiom   operations.
Sedimentation  lagoons  are  commonly used at steam electric
power plants.  Some plants employed configured tanks.  Tanks
can be used where space limitations  are  important.   Tanks
constructed   for   solids  removal  usually  have  built-in
facilities for continuous or  intermittent  sludge  removal.
Designs  based  on  maximum flow anticipated can provide the
best performance.  Equalization can be provided to  regulate
flow.   The  retention  time  required  is  related  to  the
particle characteristics.

Oil  and  Grease.   Certain  preventative  measures  can  be
applied  to  prevent spillage of oil and the entrance of oil
into the plant drainage system.  Flotation is  efficient  in
removing  emulsified oil and requires minimum space.  It can
be used without  chemical  addition,  but  demulsifiers  and
coagulants  can improve performance in some cases.  Whenever
possible, primary separation facilities should  be  employed
to  remove  free  oil and solids before the water enters the
flotation unit.  Multistage units are  more  effective  than
single-stage   units.    Partial   recycle  units  are  more
effective than full-pressure units.  Oil removal  facilities
including single-cell flotation can achieve effluent oil and
                            106

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Table VII-1 .
END-OF-PIPE TREATMENT METHODS
Method
Neutra 1 i zati on
Chemi cal reduction
Preci pi tatlon
Ion exchange
Liquid/liquid
extract! on
object! ves
usua 1 ly to wi thin
reducti on of
hexaval ent
chromium to
trlvalent
chromi urn
removal of ions
by formi ng s 1 i ght-
ly soluble salts
removal of i ons by
sorpti on on surface
nf a SO" » d n-a t>-i x
removal of soluble
organics or chemi-
cal ly charged pol -
lutants
Chpmicals or Process
lime
sulfur dioxide, pH range of
sodi un bisulfite, 2-3
sodium' metabi sulfi te,
ferrous sal ts
lime, hydrogen optimum pH
soda ash moved
synthetic cation may require pH
ant on exchange adjus tment
resins
immiscible solvents may require
that may contain pH adjustment
chelating agents
E f f i c i ency of
99. 7%
copper-96 . 6s
z1nc-99.7S
phosphate-93.6X
cyamde-99°.
copper-95*
1ron-lOOX
cadmi um-92X
nickel-lOOS
z1nc-75S
phospha te-90i
sul fate-97-
alum1num-98S
phenol -991
chromi um-99t
n1ckel-99S
z1nc-99%
Muoride-68S
iron-991
•olybdenum-90*
Advantages
1 -opera tes at
amb i en t en v i ron -
men t
2-we 11 sui ted for
3-hi gh ra te of re-
actions
ambient en-
v i ronmen t
2-wel 1 s ui ted
to automati c
control
1 -operates at
ambient en-
automa ti c control
1 -operates at am-
2-well sui ted to
3-can be used to
1 -can be used to
able cons ti tuents

scaling in sludge
tanks and
condui ts
1 arge
qudnti ti es
of sludge
3-may generate
toxic by-
products
careful pH s 1 udge
control
2-presence of
oxidants
{oxygen,
feme ion)
qu i red dose
of the reduc-
ing agent
3-Sulfur di-
oxide is
toxic and
corrosive
1-requires periodic removal o'f
careful pH s 1 udge
control
more than a
single step
to remove a
mixture of
Ions
3-presence of
chel ati ng
agents ( i .e . ,
cyani de) i n-
creases the
solubi 1 i ty of
many metals
effluent
jected to
attack by
oxi di 21 ng
agents (i.e.
ni tri c acid)
3-subjected to
cloggi ng and
foul i ng
4-costly to
operate
1-effluent re- periodic regenera-
qui red addi- tlou of sol vent
tlonal
2-subjected to
chemical in*
tcrference
3-sol vent sys-
ttH may
deteriorate
Mi th repeate
ust
Demons trati on
by industry
by industry
by industry
status
nsively

used primarily in water
treatment operation for
production of boiler fee
water
process 1s not highly
developed for industrial



-------
                                                        Table  VII-1.     END-OF-PIPE  TREATMENT  METHODS    (CONTINUED)
       Method

     Disinfection
objectives
destructl on of
ml croorgam sms
Chfmi ca 1 s or
chlorine, hypo-
chlorite salts ,
phenol .phenol
salts of heavy
meta 1 s , chlori ne
dioxide
Process
Efficiency of
may requi re pH
adjustment


Advantages
1 -operates at
ambient en-
vi ronmen t
2-well suited to
automati c control
Limitations
1-may cause
taste and
color pro-
blems
2-di si nfectant
are toxic
compounds
Requi red maintenance
period i c 1 oadi rtg
of chemicals
Demonstration
disinfection
by industry
s tatus
by chlorine

     Adsorption
     Chemical oxidation
O
Co
     Dis ti11ati on
removal of sorbable activated carbon,    may require  pH
contaminants        synthetic sorbents   adjustment
                         destruction of  cya-  chlorine, hypochlo- pH=9 5-10
                         mdes               rite salts, ozone   (first step)
                                                              pH=8 (second
                                                              step)
                        separa ti on of dis-
                        solved ma t te r by
                        evaporafi on of the
                        water
                   1-multistage flash   may require  pH
                     distillation      adjustment
                   2-multiple-effect
                     long-tube verti-
                     cal  evaporation
                   3-submerged tube
                     evaporation
                   4-vapor compres-
                     s ion
depend on

was te

99 6 *










1005













the !-high removal ef -

qui remen t


bient tenperature
2-we 11 su i ted to
au to ma t i c
control







1 -produces hi gh
qua 1 1 ty water
2-can be used to
recover va 1 u-
ab 1 e cons ti t-
uents








1 -waste re- periodic reg«*nera-
t reatment
regenerati on
during re-
9
ful pH con- sludge and loading
trot of chemi ca 1 s
2-may nrnrfi_'C*
poi sonous
gas
3-second re-
action is
slow
4-subjected to
chemi ca 1
i nterference
1-high energy periodic cleaning to
requirement remove scale
2-may requi re
pretrea tment
of waste
3-cause sea 1 -
i ng of
boi 1 ers and
heat ex-
changers
a. may requ i re
post treat-
ment of
water
                                                                                                                                                             practiced extensively
                                                                                                                                                             by  industry
                                                                                                                                    practiced  extensively
                                                                                                                                    by industry
                                                               practiced only to  a  moderate
                                                               extent by industry,  pnmarjl
                                                               the  submerged tube type  unit
     Reverse osmosi s
     Electrodi a lysis
                         separation of di s-
                         solved  matter by
                         f11tration through
                         a semi permeable
                         membrane
removal  of
dissolved
polar compounds
                   1-tubular membrane
                   2-hoHow-ft Her
                     modules
                   3-Spiral-wound flat
                     sheet membrane
                                             solute is exchanged
                                             between two liquids
                                             through a selectlve
                                             semi permeable mem-
                                             brane in response to
                                             differences in chemi-
                                             cal  potential between
                                             two  liquids
                                                                              TDS-62-965
1-produces  high
  quality water
2-can  be used to
  recover valuable
  const!tuents
3-operates  at am-
  bi er-1  tempera-
  ture
1-can  be  used to
  recover and re-
  use  va1uable
  chemicals
2-produces hi gh
  qua 11ty water
1 - 11mi ted  range  periodic replacement of
  of operating   membrane
  tempera tures
  and concen-
  trati ons
2-membrane i s
  susceptible
  to fouli ng by
  suspended
  solids  or
  attack  by
  many  chemi-
  cals
1-membrane 1s
  subjected to
  foul ing by
  suspended
  solids
2-membrane and
  electrode are
  subjected to
periodic  replacement of
membranes  and electrodes
                             very  11 r-,1 ted use in
                             industrial wastewater
                             treatment
not practiced  by
i ndustry

-------
                                               Table  VII-1.   END-OF-PIPE  TREATMENT  METHODS   (CONTINUED)
Method

objectives

equi pment

used



Efficiency

of

Advantages

Limitations

Required maintenance





 Freezing
separation of so-
1ute from 11qyid
by  crystallizing
the solvent
1-direct refriger-
  ati on
2-indirect refrig-
  eration
1-produces high
  quality water
2-low operating
  tempera lure
  mhibi t s
  corrosion
1 -ht gh energy
  requ j rement
?-refrigerant
  pay be con-
  tatni na ted in
  the direct
  refri geration
  method
periodic  cleaning and re-
placement of filters and
sc reeris
                                                                                                                                      unproven method
                                                                                                                                      waste treatment
                                                                                                                                      application
o
VO

-------
       Table  VII-2
Unit
operation
Process
objectives
Methods or
units csed
Re tentl on
tine
Chemicals
used
Efficiency
of removal
Advantages
Skimming
Clarification
Flotation
Micros training
Filtration
Screening
TMckenlng
Pressure
filtration
Heat drying
Ultraflltratlon
                    removal  of  floating
                    solids  or  liquid
                    wastes  from the water
                    removal  of  suspended
                    solids  by settling
                    separation  of sus-
                    pended  solids by
                    flotation  fo!lowed by
                    s k I mm 1 n g
                    removal  of  suspended
                    solids  by passing  the
                    wastewater  through  a
                    mlcroscreen
                    removal  of  suspended
                    solids  by  filtration
                    through  a bed of sand
                    and  gravel
removal  of large solid
matter by passing
through  screens
concentration of
sludge by removing
water
                         1-settUng ponds
                         2-clarfflers
                                                              1-15 mln
                                                                45 mln
                                                                       70-901       1-slmple to operate
                                                                                    2-reduces down stream
                                                                                      treatment
                                                                                    3-hlgh efficiency of
                                                                                      removal
                         l-froth  flotation
                         2-dlspersed air
                           flotation
                         3-dlssolved air
                           flotation
                         4-gravlty  flotation
                         5-vacuum flotation
                         1-muttlmedla bed
                         2-mlxed media bed
                     20-30
                      mln
                                                                 N/A
                                                                 H/A
1-coarse screens
2-bar screens
3-commur1cat1ng
  devices

1-grav1ty thUk-
  enl ng
2-alr flotation
  thickening
separation of solid  from
liquid by passing
through a semlpermeable
membrane under pressure
reduce the water content 1-flash  drying
of sludge                2-spray  drying
                         3-rotary kiln
                           drying
                         4-multfple hearth
                           drying

separation of macro-
molecules of sus-
pended matter from the
waste by filtration
through a semlpermeable
membrane under pressure
                                                                 N/A
                                                                 N/A
                                                                1-3 hrs
                                                                 N/A
                                                                 N/A

coagulan ts ,
coagulant al ds
pH adjustment
aluml urn and
ferrl salts.
actlv ted sl-
1 1 ca rganf c
polym ri.
none





none







none

none





none









none


none



to
15 mg/1
90-991




70-80%
(23*)
50-60*



50-99%







50-99X

depends on
the nature
of sludge



to 50-75%
moisture
content







to 81
mol sture
content
Total solid
removal of
951 and
above

1-hfgh efficiency of
removal 1 n short
l-eff1dent process




1-no chemicals require
ment
2-1ow cost of opera-
3-h1gh efficiency of
removal of large
particles
1-low Initial and
operating costs
2-small land re-
qul rement
3-no chemicals re-
quf rement
4-partial removal of
dissolved matter
1 -protect down stream
treatment equipment
1-facllitates further
s ! udge process 1 ng
at ml nf mum cos t
2- flotation thickeners
are more ef f 1 ci ent
than gravl ty thlck-
1-htgh separation
ef f 1 ci ency for
difficult to re-
move solids
2-Hlter cake has a
low water content
3-suspended solids
content of f 1 1 -
trate is low
4-minlmum maintenance
1-produces dl s-
posabl e product

1-low capital Instal-
lation and operating
costs
2-unsensl tfvl ty to
                                                                                                          the chemical nature
                                                                                                          of waste
                                                                                                        3-no  waste pre-
                                                                                                          treatnent 1s re-
                                                                                                          qu1red
 Sandbed drying
 Vacuum
 filtration
 removal  of  moisture
 from sludge by  evapor-
 ation and  drainage
 through  sand.

 solid liquid
 separation  by  vacuum
 1-covered beds
 2-uncovered beds
filtration
   1-2 day
as filter
15-20%
                                                produces
                                                301 solid
                                                in filter
                                                cake
1-low costs  of
  cons truetlon.
  operation  and
  malntenance
                                          l-h1gh1y  efficient
                                            process
 Centrlfugatfon
 liquid/sol Id separ-
 ation by centrifugal
 force
  1-dl.sc centrifuge
  2-basket centrifuge
  3-conveyor type
   centrifuge
                                                                  N/A
                             moisture 1s
                             reduced to
                             65-70*
             1-small  space
               requi rement
             {-simplicity 1n
               operati on
 Emulsion
 breaking
 separation between
 emulsified oil and
 water
                                                                 2-8 hour
                                                    110
                                  alumlnum
                                  salts. Iron
                                  salts, pH
                                  adjustment
                                  (3-4)
                                                                                            >99l
                                          l-h1ghly  efficient
                                            process

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 Table  VII-2.    SOLID/LIQUID  SEPARATION  SYSTEMS  (CONTINUED)
Unit operation Limitation
Skimming

conta i ni ng
mat ter
tnergy
requl rement

floating
Main tenance
periodic 1 ubr 1 -
cat i en
Demons tratt on
s ta tus
practt ced
1 ndus try
extensively by
Clarification     1-h fgh operating cost     nominal
Flotation
                  1-efMciency depends  on   nominal
                    the nature of  the  par-
                    ticles surface
                                            periodic loading     practiced extensively  by
                                            of  chemicals and     industry
                                            removal of siudge

                                            routine maintenance  practiced extensively  by
                                            of  pumps and motors  industry
Mlcrostraln1ng
                  1-may result 1n high
                    head loss
                  2-1ow e ffici ency of
                    remova I of sira 11
                    particles
                                            routing cleaning
                                            of  screens
                   practiced only to a moderate
                   extent,  primarily 1n municipal
                   wastewater treatment plants
Filtration         1-wastewater with high
                   suspended solids  con-
                   ten t require pre-
                   treatment
                  2-n T gh 1osses of head
                  3-produces wastewater
                  4-opera t ion is com-
                   11cated and re -
                   quf res traim ng
                                          sma 11
                                            routlne ma1n-
                                            tenance of pumps
                   practiced extensively primarily
                   In  water treatment plant
Screen\ng
ThIcken i ng
1-minor  effect on
  overa11  treatment
2-may result  in high
  h««d loss

1-sens itive  to fIow
  rate of  both
  effluent  and sludge
  remova1
                                            sma) ]
                                                               periodic cleaning
 perlodi c  cleanlng
 1 ubri cation
                    practiced  extensively
                    by Industry
 practiced extensively
 by  industry
Pressure           1 -short  life of filter
fl 1 tration           cloth
                  2-raquires operating
                    personne1
                                            small
                                             periodic cleaning
                                             and  replacement
                                             of filter
                    not practiced by
                    Industry
Heat drying
                  1 -costly process
                                            high
                                                               periodic cleaning
                                                                rotary  kilns are used
                                                                by  industry to small
                                                                extent
Ul trafi1tration
                  1 - 1imlted range of
                    operat1ng tempera-
                    tu re
                  2-membrane 1s sus-
                    ceptible to attack
                    by  many chemi ca1s
                  3 - 11 m 11 e d range of
                    app1i ca 11ons
                  4-membrane can be
                    fouled by suspended
                    sol ids
                                            nomlna1
                                             routine maintenance used  by  Industry
                                             of  pumps            primarily to treat
                                                                o11y  was te
Sandbed drying
1 -requi res  a  1arge
  area  of  land
                                           small
perlodic  removal
of sludge
practiced extensively
by Industry
Vacuum
fi 1 tration
Centri fugatlon
1 -n»o^  operating          r.ominal
  cos t
2-fiItrate may re-
  qui re further
  t rea tment

1-high  operating          nominal
  cos t
2-may  produce nolse
periodic  cleaning   practiced  extensively
and replacement     by Industry
of filter media
periodic  lubrfca-   equipment  for  1n-
ti on and  cleaning   dustrial wastewater
                   treatment  is under
                   deve1 opment
Emu)sion
break i ng
1 -t equir es segre-
  gation  of oily
  waste  from non
  o 1 ly was te
                                           small
                                           111
routine  maintenance practiced  extensively
of pumps and motors by industry
and periodic re -
moval  of sludge

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              Table VII-3.  TREATMENT  OF MAJOR POLLUTANTS
      Pollutant
Common
pH
Total  suspended  solids
Specific
0i1and  Grease
Hexavalent chromium

Chromium (total)


Iron

Copper


Zinc


Chlorine
     Treatment method
1  - Neutralization
1  - Clarification
2 - Flotation
3 - Filtration
1  - Skimming
2  - Gravity  flotation
3  - Dissolved  air flotation

1  - Chemical reduction

1  - Precipitation
2  - Ion exchange

1  - Precipitation

1  - Precipitation
2  - Ion exchange

1  - Precipitation
2  - Ion exchange

1  - Dissipation
2  - Aeration
3  - Chemical reduction
Residual  concentration
  achievable  (mg/1)(17)
to pH of 5.5  to  9
          5-30
          5-15
          2-10
         10-30
           20
           15

          0-1

          0.006
          0.01

          0.3

          < 1.
          0.03

       0.5-2.5
          20

Below detection  limits
Below detection  limits
Below detection  limits
                                      112

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grease  levels  as low as 10-20 mg/1, while multistage units
can achieve 2-10 mg/1.

Chromium.  The most common method  of  chromium  removal  is
chemical  reduction  of hexavalent chromium to the trivalent
ion and subsequent  chemical  precipitation.   The  standard
reduction  technique is to lower the waste stream pH to 3 or
below by addition  of  sulfuric  acid,  and  to  add  sulfur
dioxide,    sodium    bisulfite     (or    metabisulfite   or
hydrosulfite) , or  ferrous  sulfate  as  a  reducing  agent.
Trivalent  chromium  is  then  removed by precipitation with
lime at pH 8. 5-9.5.

The residual of hexavalent chromium after the reduction step
depends on the pH, retention time, and the concentration and
type of reducing agent.

A  process for chromate removal from cooling water has  been
recently  developed.   This  is  an  electrochemical process
whereby an electrical current is  applied  to  a  consumable
iron  electrode.   The resulting ferrous ions react with the
wastewater  chromate  in  accordance  with   the   following
equation:
    3 Fe2+ + CrOft =+ 4 H^O = 3 Fe3+ + Cr3+ + 80H^     (1)

Because of the  alkaline  pH  both  the  iron  and  chromium
precipitate as metal hydroxides and are subsequently removed
in  a  clarifier.   The produced ferric ion further enhances
the coagulation and settling of suspended solids.

Chromate residuals from this process have been  reported  to
be less than 0.05 ppm.  Costs of treatment are claimed to be
fairly  low  and  the  operation is automaticall controlled.
The process is also applicable for removal of  other  metals
ions such as zinc, copper, nickel, tin, iron, etc. (16) .

Copper.   Effluent concentrations of less than 1 mg/1 can be
consistently achieved by precipitation with  lime  employing
proper  pH  control and proper settler design and operation.
The minimum solubility of the  metal  hydroxide  is  in  the
range of pH 8.5-9.5.  In a power plant, copper can appear in
the  wastewater effluent as a result of corrosion of copper-
containing  components  of  the  necessary  plant  hydraulic
systems.  Normally,  every  practicable effort is made,  as a
part of standard design and  operating  practice  to  reduce
corrosion of plant components.  Copper is not usually used in
construction  of  once-through  boilers and consequently, is
rarely found in corresponding spent cleaning solutions (12).

Iron.  In general, acidic and/or  anaerobic  conditions  are
necessary  for appreciable concentrations of soluble iron to
                            113

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exist.   "Complete"  iron  removal   with   lime   addition,
aeration,  and settling followed by sand filtration has been
reported.  Existing technology is capable  of  soluble  iron
removals  to levels well below 0.3 mg/1.  Failure to achieve
these levels would be the result  of  improper  pH  control.
The  minimum solubility of ferric hydroxide is between 7 and
8 (12).  In some cases, apparently soluble iron may  actually
be  present  as  finely  divided  solids  due to inefficient
settling of ferric hydroxide.  Polishing treatment  such  as
rapid  sand  filters  will  remove these solids.  In a power
plant, iron, as with copper, can appear  in  the  wastewater
effluent   as  a  result  of  corrosion  to  iron-containing
components  of  the  necessary  plant   hydraulic   systems.
Normally,  every  practicable  effort  is made, as a part of
standard design and operating procedure, to reduce corrosion
of  plant  components.    Excessively   stringent   effluent
limitations   on  iron,  as  with  copper,  may  necessitate
complete design and  alter
-------
Continuous  Waste  Strgams.   Continuous  wastewater streams
consist primarily of cooling system wastes,  either  of  the
once-through  or  the  recirculating  system  blowdown type.
None of the plants contacted in this  study  were  found  to
discharge   once-through  cooling  water  to  publicly-owned
treatment  facilities.    Where   such   discharge   occurs,
consideration  should  be  given  to removing this discharge
from the sanitary sewer system, since  the  large  hydraulic
loading   will   decrease  the  effectiveness  of  the  POTW
treatment process.

Residual chlorine contained in  once-through  cooling  water
discharges  can  be  removed  by  so-called "dechlorination"
processes.  Methods of dechlorination  include  addition  of
reducing  chemicals, passage through fixed beds of activated
carbon and  aeration.   Reducing  chemicals  include  sulfur
dioxide  (SO2) , sodium bisulfite  (NaHSO_3) , and sodium sulfite
(Na.2SO_3) .  ~~ Of  these  agents,  sodium  bisulfite  is  most
commonly used (19).  Granular  activated  carbon  as  adsorb
chlorine  compounds and is oxidized by it to carbon dioxide.
Oxidizing  chlorine  compounds  such  as   chlorine    (C12),
hypochlorous   acid   (HOCl) ,  chlorine  dioxide   (C10_2)  and
nitrogen trichloride  (NC1_3) are sufficiently volative to  be
removed  by aeration  (19). Other active chlorine species are
not as volatile and may not be removed.  Data  available  to
date do not indicate that heat discharged in this waste is a
problem to a POTW.

Closed  cycle or recirculating cooling water system blowdown
is discharged  into  POTWs  by  a  number  of  plants.   The
discharge  may  be  continuous or intermittent.  Significant
parameters of pollutants that may be found in cooling  water
blowdown  may  include  chlorine,  hypochlorous acid, sodium
hypochlorite, phosphates, chromates, zinc compounds, organic
biocides,  dispersing   agents,   and   depending   on   the
constituents  in  the makeup water supply, various inorganic
salts resulting from the concentration of those constituents
and the necessity  of  maintaining  the  pH  within  certain
limits.   Pretreatment  may be necessary if certain types of
inhibitors and biocides are used as  internal  treatment  in
the  cooling  water  system.   These  are  likely to inhibit
biological  activity   at   the   publicly-owned   treatment
facilities  and will therefore have an adverse effect on the
treatment operation.  The extent of this effect will  depend
on  the  relative  volumes  of  cooling  tower  blowdown and
domestic wastewater.  Organic compounds used as  inhibitors,
biocides, or dispersing agents are not likely to be degraded
by  secondary  biological  treatment and will therefore pass
through  the  publicly-owned  treatment  facilities  and  be
discharged  to  the  receiving waters.  Toxicity studies are
being conducted with  individual  proprietary  compounds  in
order to establish permissible levels of discharge.
                            115

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End-of-pipe technology is available to remove most inorganic
pollutants.   Many inorganic pollutants have low solubilites
at alkaline pH, and can be removed by adding lime or another
form of alkali.  The degree of removal is a function of  the
solubility  of  the  pollutant  at  high  pH.  Some specific
pollutants such as chromium can be removed by ion  exchange,
but  the ultimate disposal of the spent regenerants presents
problems.

Periodic Wastes.  Periodic wastes  include  waste  resulting
from  boiler  and  service  water treatment, boiler blowdown
(can be continuous) , ion  exchange  water  treatment,  water
treatment   evaporative  blowdown,  boiler  and  air  heater
cleaning, other equipment cleaning, laboratory and  sampling
streams,  floor  drainage,  cooling  tower  basin  cleaning,
blowdown  from  recirculating  wet-scrubber  air   pollution
control  systems,  and  other relatively low volume streams.
These include all the wastes that  are  classified  as  "ash
transport"   and   "metal   cleaning"  wastes.   For  plants
discharging wastes to publicly-owned  treatment  facilities,
boiler  blowdown  is  generally  not a significant source of
pollution.   Water  treatment  wastes  may  or  may  not  be
significant  depending on the source of the water and method
of treatment.   Since  most  plants  discharging  wastes  to
publicly-owned  treatment facilities also obtain their water
from the municipal water  supply  system,  the  wastes  will
consist of normal constituents of the water supply, plus any
chemicals  used  in the treatment process.  If the treatment
process is ion exchange, the wastes will  contain  inorganic
acids  and  alkalis.   Combination  of wastes from anion and
cation exchanges will generally  result  in  combined  waste
stream that is acceptable to the treatment plant.  If the pH
of  the combined waste stream is outside the range of 6.0 to
9.0 normally  acceptable  to  biologically  based  treatment
process, neutralization may be required.

Evaporation  blowdown  is  usually high in dissolved solids,
but otherwise acceptable for discharge to the publicly-owned
treatment  facilities.    The   dissolved   solids   consist
primarily  of  concentrated constituents of the public water
supply and do not have any adverse effect on  the  treatment
plant,  receiving water.

Floor  drains may be a significant source of pollution, with
oil and grease  as  the  most  significant  parameter.   The
regulations  for  direct  discharge limit oil and grease for
all low volume wastes taken collectively to 20 mg/1  on  any
one  day,  and  15 mg/1 average for 30 consecutive days, but
local authorities  may  impose  more  severe  limits.   Most
municipal  pretreatment ordinances also limit oil and grease
so that pretreatment may be required  for  removal  of  this
pollutant.
                            116

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End-of-pipe  technology  is  available  and  is used by some
plants.  The  technology  consists  of  gravity  separators,
either   unassisted   or   assisted  by  flocculants  and/or
dissolved  air   flotation,   followed   if   necessary   by
filtration.   The  technology  is  able  to meet the desired
standards at a  minimal  cost.   However,  to  meet  desired
standards  efficiently  only  those waste streams containing
excessive oil  and  grease  should  be  passed  through  the
treatment unit.

Metal Cleaning Wastes.  The most significant of the periodic
wastes  in  terms of their potential impact on the publicly-
owned treatment facilities are metal cleaning wastes.  Metal
cleaning wastes are produced intermittently while units  are
shut  down.   The  efficiency  of  electric power production
depends largely on the efficiency of heat  transfer  between
the  combustion products and the boiler water.  All metallic
heat transfer surfaces have a tendency to either corrode  or
collect  deposits.   Both  corrosion  products  and deposits
reduce the efficiency of heat transfer and must therefore be
removed periodically.

There are two main types of cleaning operations:   waterside
and  fireside.   Waterside cleaning consists of cleaning the
inside of tubes, and other boiler water  passages.   Due  to
the  inaccessibility  of  these surfaces, the only practical
and generally accepted method of  cleaning  is  by  chemical
means.   The cleaning typically proceeds in three stages:  a
bromate  soak,   an   acid   cleaning    (usually   inhibited
hydrochloric  acid),  and  finally a passivation stage.  The
total operation takes about two days and produces about five
boiler volumes of wastes, with each stage  consisting  of  a
fill,  drain, fill and rinse operation lasting about one and
one-half to two hours.   For  multi-unit  plants,  only  one
boiler  is  cleaned at any one time, so that the majority of
the plant is operating during the cleaning cycle.

Fireside cleaning is more  mechanical,  consisting  of  high
pressure   nozzles  directed  against  the  surfaces  to  be
cleaned.  The cleaning solution often  contains  alkalis  to
dissolve  oil, and grease and detergents to keep the removed
material in colloidal suspension.  Fireside cleaning is done
on both  the  fireside  of  the  boiler.   Similar  cleaning
procedures are employed on the air preheater.

Pollutants  contained  in  the cleaning solutions consist of
both the chemicals used in the  cleaning  solution  and  the
material  removed  from  the heat transfer surfaces.  Tables
VII-4 and VII-5 give  ranges  of  composition  for  chemical
cleaning  and fireside cleaning wastes, respectively.  These
pollutants are generally not removed by biological secondary
treatment and may have an adverse effect  on  the  treatment
                            117

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process,  depending on the ratio of metal cleaning wastes to
total flow at the publicly-owned treatment plant.

Options for process modifications for metal cleaning  wastes
are  small.   End-of-pipe  technology  is  available for the
removal of most  of  the  pollutants  resulting  from  metal
cleaning operations.

Basic  technology  for  removing  pollutants  from the waste
stream consists of retention,  storage  and  combination  of
waste streams, raising the pH to precipitate metallic salts,
removal  of precipitated solids and pH readjustment of final
effluent for discharge to  public  sewers.   Operating  data
from  many  power  plants  shows  that copper from the metal
cleaning wastes can be reduced to less than 1 mg/1  by  lime
or caustic soda addition.  Two of these plants use chelating
agents  in their cleaning process while all of the remaining
facilities do not.  The power plants  which  discharge  into
POTW  can  achieve the 1 mg'/l copper limitation more readily
since they do not have to reduce iron at the same time to  1
mg/1.

Since  metal  cleanings  are  infrequent  operations,  (some
plants clean their boiler only once every five  years)  many
plants prefer to have them hauled off and treated by private
contractors.   Most  of  the expertise for treating cleaning
wastes has been developed by the  cleaning  contractors  who
are  generally  being  asked  to include waste treatment and
disposal as part of the cleaning contract.

Ash Transport Water.  Hydraulic systems for handling  bottom
ash   are   used   primarily   by  coal-fired  plants.   The
preliminary listing of plants discharging to  publicly-owned
treatment   plants  contain  coal-fired  plants.   Hydraulic
systems are used for fly ash removal, usually in conjunction
with scrubbers for sulfur dioxide removal.  Where  scrubbers
are  part of the air pollution control system, provision has
to be made for handling of the sludges  resulting  from  the
operation.   This sludge is not suitable for disposal to the
public sewer system.

Air Pollution Control  Wastes.   There  is  normally  little
liquid  effluent  from  sulfur dioxide scrubbers.   The water
within the system is usually recycled as much as possible by
dewatering the sludge to a filter cake.  Some  water  leaves
the  system  as  steam  with  the gaseous emissions and some
water  becomes  entrained  in  the  sludge  cake,   but   the
objective  of  good  operation  is to minimize the amount of
water in the sludge cake.  The water retained in the  sludge
cake  is  sufficient  to  meet  the  requirements for system
blowdown.
                            118

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   Table VI1-4.TYPICAL COMPOSITION OF
           BOILER CHEMICAL CLEANING WASTES
     Component                   Amount, T_b_.

Hydrochloric Acid                  46,500
Iron                                3,800
Copper                                500
Sodium Bromate                        930
Ammonium Carbonate                  1,675
Ammonium Hydroxide                 14,600
Chromate Inhibitors                 1,600
Thiourea                            7,750
Ammonium Bifluoride                 3,775
Sodium Carbonate                    7,750

plus small amounts of silica, phosphates, nickel,
zinc, aluminum, titanium, manganese and magnesium
Size of unit                       500 MW
Volume of wastes                   95,000 gal
    Table VII-5. TYPICAL COMPOSITION Of
          BOILER FIRESIDE HASH HASTES

         Component              Concentration, mg/1

Suspended Solids                   1,000 - 3,000
Iron                                 500 - 1,000
Copper                                10 -    20
Nickel                                50 -   300
7inc                                  15 -    25
Oil and Grease                       150 -   300

Volume, gal/KW IGC                   200 - 1,000
(once/year for each boiler)
                119

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Occassional Wastes.  Occassional wastes are those  that  are
caused  by  contamination  of stormwater runoff by materials
stored on the plant site. The principal type of contaminated
stormwater is coal pile runoff, and this  is  restricted  to
coal  fired  plants.   A  significant number of urban plants
have been converted from coal to oil fired, but still retain
the coal capability and may keep a coal  reserve  stored  on
the  site.  The coal reserve may become a significant source
of pollution due to the interaction of water  and  air  with
some of the impurities in the coal, notably iron and sulfur.
No  plants  discharging  coal  pile runoff to publicly-owned
treatment facilities  were  uncovered  during  the  industry
survey.

A  type  of  process  modification  would  be  to  cover the
inactive coal pile with plastic sheeting the way a  baseball
infield  is  covered  in the rain.  This would eliminate the
formation   of   pollutant    containing    waste    stream.
Alternately,   the  waste  stream,  once  produced,  can  be
neutralized with lime as an end-of-pipe treatment,  and  any
suspended solids allowed to settle.  This practice is common
in related industries.

WATER MANAGEMENT

The  varied uses that are metde of water in a power plant and
the wide range of water  quality  required  for  those  uses
present  this industry with an unusual opportunity for water
management  and  wastewater  reuse.   Indeed,  many   plants
developed water management programs that make use of all the
wastewater  streams  produced  by  recycling  them into unit
processes which  tolerate  lower  water  quality   (e.g.  ash
handling).    However,  to  develop  and  implement  a water
management program of  no  discharge,  it  is  necessary  to
evaluate  the  water  requirement  of  each  segment  of the
process  as  well  as  the  specific  factors  which  affect
individual  plant  water  needs.   Such  factors include the
nature of the raw water source, the location  of  the  plant
and  its  climatic environment, water availability and water
cost, and the local requirement   for  effluent  limitations.
The chemical composition of the raw water source affects the
magnitude  of the discharge from almost every segment of the
process.  To  deionize  water  with  high  dissolved  solids
content to produce boiler feedwater, the ion exchange system
produces  more regenerant.  Further, highly dissolved solids
contents would also lower the concentration cycle of closed-
loop recirculations  cooling  system,  and  therefore  would
increase  the  blowdown  from  these  systems.   In areas of
excessive rainfall closed-loop recirculating  systems  would
have  to  be  bled  more  often   to prevent the systems from
overflowing and may indeed be difficult to operate. In areas
where the rate of evaporation is  greater than  the  rate  of
                             120

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precipitation,  such  systems  would require makeup water to
maintain the flow.  Water availability and cost  would  have
an  impact  on  the  plant incentive to conserve water.  The
extent of wastewater treatment provided by the  plant  would
depend  on  how stringent the local requirement for effluent
limitations are.

IN-PLANT CONTROL TECHNIQUES

Control of wastewater effluents produced by the industry can
be best achieved by incorporating in-process changes capable
of reducing the volume of wastewater discharged, or reducing
the amount of pollutants in the discharge.

Such changes can be classified under one  of  the  following
categories:

    o    Process modifications;
    o    Materials substitution;
    o    Water conservation and wastewater reuse;
    o    Raw materials and product recovery; and
    o    Good housekeeping practices.

Application  of  such  techniques  can  result  in  multiple
benefits, including savings in  construction  and  operation
costs  of  on-site  wastewater treatment plants and in sewer
surcharge and other  charges  associated  with  the  use  of
publicly-owned treatment facilities.

In   power   generating   plants   there   are   theoretical
opportunities  for  a  number  of  such  control   measures.
Practically,  the  opportunities  are limited by the cost of
any major process change under "retrofit"  conditions,  that
is,  conditions  which  require  substantial  mechanical and
structural changes to an existing plant.

Process Modifications

A great number of process  modifications  are  available  to
reduce  the quantities of wastewater from a power generating
plant, or to eliminate it altogether.  In order  to  present
these  potential  modifications  in  an orderly manner, this
section has been  further  divided  into  subsections,  each
dealing with an individual wastewater stream.

Once  Through  Cooling Water.  Switching from a once-through
to a closed  or  open  recirculating  cooling  system  would
greatly  reduce  the  amount of wastewater discharged.  This
can be shown by balancing the quantity of heat  rejected  by
each of the systems.  For a once-through cooling system this
quantity is equal to the product of the water flow times the
condenser  temperature  rise.  For a recirculating system it
                            121

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can be assumed that all the heat is rejected by evaporation.
Neglecting drift and windage losses the  following  equation
can be written:

         B =    T                                (2)
         F   q(C-l)

where  B/F is the ratio of the blowdown from a recirculating
system to the discharge from once-through cooling system,  T
is  the  condenser temperature rise, q is the amount of heat
required to evaporate a unit weight of water, and C  is  the
concentration  cycle.  The concentration cycle is defined as
the ratio of the concentration of a  limiting  parameter  in
the  makeup  water  to  that  in  blowdown.    For  a typical
condenser temperature rise of 10°C and for q  equal  to  555
kcal/liter  of  water,  even  at a concentration cycle of 2,
approximately  98  percent  reduction  in  the   volume   of
wastewater  produced  would  be achieved.  This reduction in
cooling water consumption can also be classified under water
conservation and wastewater reuse category.

Switching  from  once-through  to  a  recirculating  cooling
syste,  however,  is  costly  and not always feasible. Power
plants contacted in this  study  that  utilize  once-through
systems  discharge  the  effluent directly to surface water.
Such discharges are subjected to EPA regulations which limit
the temperature and  the  chlorine  concentration  of  waste
effluents to be discharged to surface water.

Excess  total  residual  chlorine concentration in effluents
from  once-through  cooling  system  can  be  minimized   by
monitoring   and   controlling   free   available   chlorine
concentrations in the discharge stream.  A further technique
to  reduce  total  residual  chlorine   discharged   is   to
chlorinate   during   periods   of   low   condenser   flow.
Alternatively, the chlorine input  to  once-through  cooling
water  can  be  reduced  to  a level below the concentration
required  for  complete  fouling  control.   Any  biological
growth which may result would be removed by mechanical means
(12) .    This   approach   however,   is   limited   by  the
configuration of the process piping and structures  involved
at any plant.

Closed  Condenser  Cooling  System  Slowdowns.   Although the
volume  of  recirculating   cooling   system   blowdown   is
considerably   smaller   than   the   amount  of  wastewater
discharged  from  a  once-through   system,    it   is   also
significantly more polluted.  The effluent contains a higher
dissolved  solids  concentration due to the evaporation of a
large portion of the cooling water.  In addition,  chemicals
added  to  inhibit  scale  formation, corrosion, and fouling
would also be present in the blowdown water.
                            122

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Slowdown from a recirculating cooling system can be disposed
of by evaporation.  In warm, dry climates,  and  where  land
costs are relatively low, such as in the southwest, blowdown
streams  can be collected in ponds and allowed to evaporate.
Such ponds are usually lined with impervious  material  such
as  clay  or  plastic  to  prevent  water  infiltration  and
subsequent pollution of the groundwater aquifer (12) .

The residual  chlorine  concentration  in  blowdown  streams
discharged  to POTW can be controlled.  This can be achieved
by one of the following methods:

    o    Regulation through feedback instrumentation;

    o    Splitting the condenser influent into two streams
         and chlorinating one at a time;

    o    Reducing the length of the chlorination period.

Chlorination is now being questioned by  health  authorities
who  must  meet  increasingly  stringent bacteriological and
waste discharge requirements.  An increased chlorine  dosage
which may provide satisfactory disinfection requirements may
also  be  responsible  for release of an excessive amount of
polluting material  to  the  aquatic  environment.   Current
reports show that even trace amounts of chlorine are harmful
to aquatic life (12) .

Water  Treatment Wastes.  Substitution of reverse osmosis or
electrodialysis for ion  exchange  to  produce  boiler  feed
water will greatly reduce the discharge from this section of
the  process.   However,  the  technical  feasibility of the
reverse  osmosis  process  is  limited   by   the   chemical
characteristics  of  the  raw water source and by economics,
and for some plants  polishing  the  product  water  by  ion
exchange  will  still  be necessary, depending on the boiler
operating pressure.

Ash Handling Wastes.  Ash handling is the conveyance of  the
accumulated  bottom  and  fly  ash  combustion  solid  waste
product to a disposal system.  This is accomplished  by  dry
or wet processes.   In the dry process the ash is transported
to   the  disposal  area  by  pressurized  air,  vacuum,  or
mechanical means.   Dry ash handling systems do not  generate
wastewater  and  may  allow a credit for the sale of the ash
for its metal content.  Bottom ash from oil  fired  furnace,
for example, can be sold for its vanadium content.

The  wet  process can be either open or closed-loop systems.
In the closed-loop system the ash is slurried in  water  and
conveyed  to a pond or clarifier where settling occurs.  The
clarified overflow from the settling pond is recycled to the
                            123

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boiler.   The  closed-loop  ash  handling  system  does  not
generate  wastewater  except  in areas of excessive rainfall
where the system must be periodically bled.  In  such  cases
the  blowdown  may be treated in a separate system to remove
metal  ion  by  precipitation  and   suspended   solids   by
clarification.   In  areas  where the rate of evaporation is
higher than the rate of  precipitation,  evaporation  losses
from  closed-loop  ash  handling systems can be supplemented
with wastewater from other unit processes  such  as  cooling
tower blowdown.  Open-loop ash handling systems are a source
for wastewater since the transporting water is used but once
to  convey  the  ash to the settling ponds.  This wastewater
source can be eliminated by switching to dry or  closed-loop
type  systems.   Open-loop  ash  handling  systems should be
avoided when possible as the effluent from the ash pond  may
require additional treatment before it can be discharged.

Coal  Pile Runoff.  The extent of contamination of coal pile
runoff can be reduced  by  properly  constructing  the  coal
storage  area.   Inactive coal piles can be sprayed with tar
or covered with plastic sheeting  to  seal  the  surface  to
water infiltration.  A drainage system should be constructed
to collect the most polluted portion of the storm.  In areas
where  the  rate  of  evaporation is higher than the rate of
precipitation runoff can be disposed of  by  evaporation  in
ponds.   Alternatively,  cocil  pile  drainage can be used in
processes which tolerate low  quality  waters  such  as  ash
handling  systems.  If the plant is located near a mine such
water can be used in the  coal  washers  to  remove  mineral
matter.   Diversion  of  this  waste  to  ash ponds was also
considered.  However, because of the low pH of such  wastes,
coal  ash  can  be  leached  by  the  water resulting in the
formation of additional waterborne pollutants.

Air Pollution Control Scrubbing Devices.   The  non-recovery
scrubbing  process for SO^ removal from flue gas may also be
a source of wastewater if the system is bled to remove spent
solvent.   This  is  a  closed-loop  type  system  employing
recycled lime scrubbing liquor.  The process requires makeup
water  for  saturating  the  boiler  gases.  Changing to SOŁ
recovery systems would reduce the discharge from  this  part
of  the  process  as  well as allow a credit for the sale of
recovered sulfur dioxide or other  sulfur  products.   Table
VII-6  lists  some  of  the 3OŁ recovery processes currently
available.  It should be emphasized, however, that  some  of
the listed processes have reached only the pilot plant stage
of   their   development   and   cost  estimates  for  their
installation and operation are somewhat  higher  than  those
for the non-recovery processes.

Material Substitution

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The  blowdown  from  a  recirculating  cooling system can be
reduced by increasing the concentration cycle.  This can  be
achieved   by  substituting  scale-forming  ions  with  more
soluble ions,  or  by  using  sequestering  agents  such  as
polyolesters  and  phosphonates  to  prevent  deposition  of
precipitated  solid  phases.    These   dispersing   agents,
however, can become pollutants in the blowdown water.

Lime   softening  of  cooling  water  makeup  prior  to  its
introduction  into  the  system  would  also  increase   the
concentration  cycle,  though  it  may  be costly because of
large volumes of water requiring treatment.

Installation of plastic or plastic-coated system  components
would  reduce  the  extent  of  treatment  of  cooling water
makeup.   Plastic  exhibits   considerable   resistance   to
corrosion and erosion.  Many new installations using cooling
towers employ plastic.

Where  publicly-owned treatment plants containing a tertiary
step  are  used,  phosphate  and  nitrate  based   corrosion
inhibitors  could  be  substituted  for  chromates  as these
pollutants  are  removed  by  a  tertiary  treatment   step.
Chrornate-based  compounds  can  also  be  substituted  by  a
recently developed synthetic organic  corrosion  formulation
which  is  not as toxic as chromate to microorganisms.  This
formulation contains a blend  of  organic  sequestrants  and
antifoulants  for  control  of  mineral  and organic fouling
together with corrosion inhibitors which provide  protection
to  all  system  metals  (1U).  Film-form-^g sulfophosphated
organic corrosion inhibitor has also  been  developed.   The
substance  is  effective  in both fresh and salty water, and
may be considerably less toxic than chromate  (11*).

To reduce the amount of metals in  wastewater  from  cooling
system  blowdown  and  from  chemical  cleaning  operations,
boilers and condenser cooling systems could  be  constructed
of  non-polluting materials.  Tubes and piping could be made
of special alloy metals or coated so as to reduce  corrosion
and  scaling, but this can be prohibitively costly.  Cooling
towers can  be  constructed  out  of  concrete  and  ceramic
materials  and  thus  reduce  the  need for additives to the
cooling water system.  Switching to  low  sulfur  fuels  can
also eliminate the need for air pollution control devices.

Water Conservation and Wastewater Reuse

Different  water  uses  in the plant require water of widely
varying quality.  These range from the  almost  zero  solids
requirements  for  boiler  feedwater  makeup  to  the almost
unlimited solids allowed for ash transport water or scrubber
water supply.  Consequently, the wastewater produced in  the
                            125

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                Table VI1-6.  RECOVERY PROCESSES  FOR FLUE  GAS DESULFURIZATION  SYSTEMS
  Process

Double alkali
system
Chemilbau
system
Hydrogen sulfite
system
Wellman-Lord
system
Cat-Ox^ system
Shell flue gas
system
  Sorbent System
  Mode of S02_
    Removal
Aqueous solution of Chemical
Sodium hydroxide , absorption
Sodium sulfate,  &   oxides with
sodium bisulfite    CA(OH)2
  Sulfur Recovery

Precipitation of
dissolved sulfur
Fluidized bed. of
activated carbon
solution of sodium
citrate, citric
acid and sodium
thiosulfate

Aqueous solution
of sodium sulfate
and sodium
bisulfite
A bed of cupric
oxide supported
activated
alumina
    Product

Calcium sulfate
Calcium sulfite
Catalytic oxidation
to H2S04
and physical
absorption
Chemical
absorption
Chemical
absorption
Catalytic
oxidation of
S02. to SQ3 with
02. at 850°F
(vanadium oxide)

Oxidation to
cupric sulfate
Thermal stripping
with hydrogen at
1000°F and
catalytic reduction
with H2S

Precipitation of
dissolved sulfur
with H2S
Sulfur,
S02
Sulfur
1iquid
Thermal
regeneration by
vacuum and
catalytic reduction
with natural gas
Sulfur
                                                            78% sulfuric acid
                    Concentrated
                    S02

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plant   also  vary  widely  in  quality.   This  opens  many
opportunities for wastewater reuse.

Cooling system blowdown can be reused for ash  transport  or
as  scrubber water supply.  Boiler blowdown water is usually
better than the feed water supply and can be reused  in  the
plant for other purposes.

Boiler blowdown can be reduced by installing a heat recovery
system.   In such a system the blowdown is discharged into a
flash tank operating at a lower  pressure  than  the  boiler
pressure.   Because of the reduced pressure a portion of the
blowdown water evaporates to form low pressure  steam  which
can  be  condensed  and  reused  as  boiler  feedwater.  The
reduction in blowdown that can be achieved  by  this  method
depends  on  the  pressure difference between the boiler and
the flush tank.  The use  of  a  heat  recovery  system  for
boiler blowdown will also increase the thermal efficiency of
the plant.

Spent  regenerants  and  rinses from the ion exchange system
are also of a quality  suitable  for  many  purposes,  where
dissolved solids are not a limiting factor.

Some  of  the  periodic  waste  streams could be recycled or
reused if sufficient storage  is  available  to  hold  these
streams  until  needed.   Metal  cleaning  wastes after pre-
treatment or treatment could be used for low  quality  water
uses such as ash transport or scrubber supply.  However, the
cost of storage may make such reuse prohibited.

Materials Recovery

Nearly  all  chromates, used as corrosion inhibitors, can be
recovered  using  properly   designed   ion-exchange   beds.
Regenerant streams from the beds, which contain a relatively
high  concentration  of  chromate,  can  be  returned to the
cooling system as  a  usable  corrosion  inhibitor.    Plants
which  soften  boiler  feedwater  with  lime  can reuse lime
sludge  in  their  air  pollution  control  system  for  302^
removal.  Recoverying heat from boiler blowdown would reduce
thermal discharges from this segment of the process, as well
as increase the thermal efficienty of the process.  Recycling
of  fly  ash back to the furnace can be employed to increase
thermal  efficiency  by  burning  products   of   incomplete
combustion.   It  is  also possible to recover vanadium from
oil ash with high vanadium content.  Spent regenerants  from
ion  exchange  system  can  be used where the quality of the
acid and alkaline solutions is not critical.    For  example,
the  acid  solutions  can  be  used in recirculating cooling
system to maintain the pH of  the  water  below  saturation.
                            127

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Air  pollution  control  devices,  on  the  other  hand, may
require an alkaline source of water.

Good Housekeeping Practices

There are numerous alternative methods ranging  from  taking
precautionary  measures against spills of chemical solutions
or oil to pump sealing to prevent leaks.   Facilities  should
be  constructed  so  that  oil and grease contaminated water
will not drain directly  into  other  water  systems  or  be
diluted   by  rainfall  runoff.   Cleaning  up  oil  spills,
maintaining equipment to minimize leaks,  and  supporting  an
effective    surveillance   program   will   also   minimize
contamination   of   wastewater   effluents.     Controlling
additions  of  chemicals to waters used in the various units
of the process would  reduce  their  concentrations  in  the
effluents  streams.   Flow of water into  the plant should be
regulated in accordance with production rate.

SUMMARY

A variety of wastewater control and  treatment  technologies
are  available for the steam electric power industry.  Since
the  water  needs,  and  the  requirements  for   wastewater
discharge  are  specific  to  each  individual  plant,  each
control and treatment system must be developed in accordance
with  the  individual  plant  requirement  and   should   be
integrated  in  a  comprehensive  water  management program.
Special consideration should be given to in-process  control
techniques.   Often,  such  technique  can be found easy and
inexpensive  to  implement  and  yet,  they  can  result  in
substantial  reduction  in  water consumption and wastewater
discharge.
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                        SECTION VIII

              COST, ENERGY, AND OTHER NONWATER
                      QUALITY ASPECTS
INTRODUCTION
This  section  discusses  cost  estimates  for  control  and
treatment   technologies  described  in  previous  sections,
energy requirements for  these  technologies,  and  nonwater
quality  related  aspects  such as reuse of water within the
plant.  Ultimate disposal of brines and sludges,  effect  of
land  availability,  user charges and pollutants limitations
imposed by POTWs and other factors  relating  to  the  steam
electric  power  generating  point  source category are also
discussed in this Section.

Costs are  developed  in  greater  detail  for  those  waste
sources  which  potentially  are discharged to POTWs and are
potentially subject  to  pretreatment  requirements.   These
include the following:

    o    Low Volume Wastes

    o    Metal Cleaning Wastes

    o    Cooling Tower Slowdown

    o    Area Runoff and Ash Pond Discharges

Other  waste  streams  such  as  ash transport water, boiler
blowdown, and once-through cooling water are provided in the
latter part of this section.

The pollutants in discharges to POTWs are similar  to  those
for  direct  discharge  to  surface water, as covered in the
Development Document for this industrial category.

Discharges of wastewater needing pretreatment and the extent
of pretreatment vary greatly from plant to  plant  depending
on the fuel used, chemical additives employed, and a host of
other variables. These variations influence the pretreatment
costs so significantly that general industry costs presented
in  this  section  should  be  considered order of magnitude
numbers.

For most power plant wastes, the pretreatment for  discharge
to   POTW   can  involve  control  of  three  parameters  of
pollution,  pH,  suspended  solids,  and  oil  and   grease.
Control   of  pH  neutralizes  any  undesirable  acidity  or
                            129

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alkalinity.  Treatment for  suspended  solids  then  removes
suspended  metals  as well as other suspended material.  Oil
and grease is separated from the  water  phase  of  the  low
volume wastes and skimmed off.

COST REFERENCES AND RATIONALE

Cost  information contained in this report was obtained from
the following sources:

    o    Engineering estimates based on published cost  data
         for equipment, construction, and installation;

    o    Estimates and guidelines for  estimating  contained
         in  the  Development  Document  for  steam electric
         industry discharges to surface water and the  other
         EPA documents;

    o    Quotations for materials and supplies published  in
         current trade journals.

    o    Cost data obtained as a result of direct inquiry to
         industry for data on actual installations.

Interest Rates and Equity Finance Charges

Capital investment cost estimates for this study  have  been
based   on  10  percent  capital  cost  which  represents  a
composite  value  for  either  interest  rate  paid  or  the
required return on investment.

Time Basis for Cost Adjustment

All  estimated  costs  are  taken  from July, 1976 prices or
where necessary adjusted to this time basis  using  the  ENR
construction cost index of 2413 (July 1, 1976).

Useful Service Life
The  useful  service  life  of  all wastewater treatment and
disposal facilities is a function of the  process  involved,
the  quality  of the equipment and design, its use patterns,
the  quality  of  maintenance  and  several  other  factors.
Whereas  individual  companies often use service lives based
on actual local experience,  for  the  purpose  of  internal
authorization,   the   Internal   Revenue  Service  provides
uidelines for tax computational purposes which are  intended
to reflect approximate average life experience.

The following useful service life values were chosen for use
in   this  report  from  the  literature,  discussions  with
representatives of industry, and IRS guidelines data:
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    o    General process equipment          10 years
    o    Buildings, sewers, ponds, etc.     20 years
    o    Material handling equipment and
         vehicles                            5 years

Depreciation

The allocation  of  the  cost  of  capital  assets  such  as
treatment  and disposal equipment less salvage  (if any) over
the estimated useful service life of the unit or facility in
a systematic and rational manner as a  non-cash  expense  is
termed  depreciation.   For  IRS  tax  purposes  and to make
suitable  financial  allowance  for  equipment   replacement
several types of depreciation are used.  Simple straightline
depreciation  was  used as the basis of calculations in this
report.

Capital Costs

Capital costs have  been  defined  for  this  study  as  all
initial  out-of-pocket  cash  expenditures  for provision of
wastewater treatment and disposal facilities.   These  costs
will  include research, development, and feasibility studies
necessary to characterize and design the facilities land and
site   preparation   costs   when   applicable,   equipment,
construction,  installation,  and  start-up  costs, costs of
buildings,  services  and   engineering    (allocated   where
necessary) , contractor profits and contingency costs if such
exist.

Annual Capital Costs

Most  capital costs are accrued during the year or two prior
to actual use of the facility.  This present worth  sum  can
be converted to equivalent uniform annual disbursements over
the  life  of the facility by utilizing the Capital Recovery
Factor Method:

    Uniform Annual Disbursement = (P) (i) (1+i) n
    where  P = present value  (capital expenditure) ,
            i = interest rate, %/100
            n = useful life in years

Operating Expenses

Annual costs of operating  pretreatment  facilities  include
labor,    supervision,    materials,   maintenance,   taxes,
insurance, and power and energy.  Operating  costs  combined
with   annual ized   capital   costs  give  total  costs  for
pretreatment operations.
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Rationale for Model Plants

Plant costs are estimated for model plants rather  than  for
any actual plant.  Model plants are defined to have sizes of
25 MW and 500 MW capacity, which are representative of large
and small-sized operation.

Definition of Levels of Treatment and Control

Costs   are  developed  for  various  types  and  levels  of
technology:

Minimum (A or basic level).  That level of technology  which
is  equalled  or  exceeded  by  most  or all of the involved
plants.

Usually, money for this treatment  level  has  already  been
spent   (in the case of capital investment) or is being spent
(in the case of operating and overall costs).

B,Cfp--LeveIs.  Successively greater  degrees  of  treatment
with  respect  to critical pollutant parameters. Two or more
alternative treatments are developed when applicable.

Basis for Pretreatment Costs

In development of cost estimates  found  in  Tables  VIII-1,
VIII-2,  VIII-4,  and  VIII-5,  it  is assumed that only the
following wastewater effluents are discharged to  POTWs  and
may, therefore, require pretreatment.

    o    Low Volume Wastes
    o    Metal Cleaning Wastes
    o    Cooling Tower Slowdown
    o    Area Runoff and Ash Bond Discharges
    o    Boiler Slowdown

Low  volume wastes include ion-exchange regenerants, spills,
leaks,  air  pollution  control  system  bleed  offs,   area
washdowns, and other miscellaneous wastewater streams.

Metal  cleaning  wastes  include  tube  and  fireside boiler
cleaning products, as well as air cleaner wastes.

Area runoff includes rainwater runoff from coal piles.   Ash
pond overflows and blowdowns are designated as discharges.

Costs  have  been  addressed  iseparately  for  the following
wastes:

    o    Ash Transport Water
    o    Boiler Blowdown
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Reasons for addressing these sources  of  wastes  separately
are  discussed  in  detail  in  Section  VII,  but  are also
discussed briefly below.

Ash transport water  from  coal-fired  plants  is  generally
recirculated   after   sedimentation,  and  the  purpose  of
sedimentation is  process  rather  than  pollution  control.
Overflows  from ash ponds are included in the wastewater for
pretreatment.

Boiler blowdown can be, and sometimes is, discharged to POTW
without pretreatment.  In can be  handled  at  the  combined
plant  without  incremental  costs.   However, based on data
contained in Section V the quality  of  boiler  blowdown  is
better  than  that required for almost any in plant use, and
it is recommended that boiler blowdown  not  be  mixed  with
other waste streams for discharge to the POTW.

No  plant  contacted  in  this  study was found to discharge
once-through cooling water to a POTW.  Therefore, costs  are
not generated for pretreatment requirements.

Cost Variances

The  effects  of  age,  location,  and  size  on  costs  for
treatment and control have been considered and  are  in  the
body of this section.

COSTS FOR PRETREATMENT

Waste  types  covered  in this subsection include low volume
wastes, metal cleaning wastes, cooling tower blowdown,  area
runoff  and ash pond discharge.  Since the wasteload differs
depending on  the  fuel  source  used,  cost  estimates  for
pretreatment  of  wastewater  effluents  from steam electric
plants have been divided into those plants  burning  gas  or
oil and those using coal.

Oil and Gas Fired Plants

Oil  and  gas-fired  plants  probably  will have no ash pond
discharge, no air pollution control wastewater, or coal pile
runoff.  Therefore,  these  plants  have  essentially   ion-
exchange   regenerants,  miscellaneous  low  volume  wastes,
cooling tower blowdown and metal cleaning wastes.

Estimated wastewater volumes in  liters/day  (GPD)   for  the
plant sizes given are:

                             25 MW Plant     500 MW Plant
                            133

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    o    Low Volume Wastes
          Ion-exchange re
           generants          11,400(3000)     454,000(120,000)
          Miscellaneous       3,800(1000)     151,400  40,000)

    o    Metal Cleaning
         Wastes               380(100)      10,200(  2,700)

    o    Cooling Tower
         Slowdown          94,600(25,000)  1,892,000(500,000)

The  low  volume wastes contain primarily acids and/or bases
and perhaps some oil.  The  metal  cleaning  wastes  contain
acids,  bases, metals, oil and grease, and suspended solids.
Cooling tower  blowdown  may  contain  chromates,  chlorine,
chlorinated phenols, mercury, phosphate, zinc and many other
additives  commonly  used  in  cooling  tower  systems.   For
purposes of cost analysis, however, cooling  tower  blowdown
is  assumed  to  contain only free chlorine (chlorine is the
most commonly reported biocide used).

Defined Pretreatment Levels

The raw wastes requiring pretreatment prior to POTW disposal
are similar to those described in the  Development  Document
for direct dischargers, and use has been made of the data on
wastewater   volumes,  waste  loads  and  other  information
contained therein.  The minimum pretreatment level,  defined
as  Level  A,  consists of that level of technology which is
equalled or exceeded by most or all of the existing  plants.
This  level involves some flow equalization and combining of
wastes to get the benefit of some neutralizing and  diluting
effects. Expenditures, both capital and operating are small.

Level  B  pretreatment  involves  equalization of low volume
wastes, neutralization to a pH 6-9 and skimming  of  surface
oil.  Metal  cleaning  wastes  are stored in a large tank or
small pond and fed slowly to  the  neutralization  tank  for
small  volume  wastes  and  boiler  blowdown.    There  is no
pretreatment of cooling tower blowdown.

Level C pretreatment is the same as Level B except that  the
metal   cleaning   wastes  are  neutralized,  clarified  and
discharged.  Provision is made for sludge removal.

Level D pretreatment is  essentially  that  for  BPCTCA  for
direct discharge to surface water.  For this level all waste
streams with exception of the cooling tower blowdown are fed
into  a  tank  for  pH  adjustment   (optimum  in the 9-11 pH
range),  oil  is  skimmed  from  the  liquid  surface,   and
suspended  solids  are  removed in a clarifier. Acid is then
added to reduce pH to 6-9 prior to discharge.   Cooling tower
                            134

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                                      DRAFT

                                   TABLE VIII-1


                    WASTEWATER  TREATMENT COSTS AND RESULTING
                    WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT
SUBCATEGORY ^ Ojl _o.r  Gas  F1 red PI ant

PLANT SIZE  __H-'jW

PLANT AGE
                                PLANT LOCATION
                          COSTS OF TREATMENT TO ATTAIN SPECIFIED LEVELS
COST CATE80RY
TOTAL INVESTED CAPITAL
ANNUAL CAPITAL RECOVERY
ANNUAL OPERATIVE AND MA'STEMANCS
COSTS (EXCLUDING CKERJYAND POWER!
ANNUAL INS P.tt AKO PO*E* COSTS
TOTAL ANNUAL COSTS

COSTS($) TO ATTAIN LEVEL
A
10,000
$1,600
Small
Small
1,600

B
50,000
8,150
10,000
Small
18,150

c
60,000
9,760
13,000
500
23,260

0
120,000
19,500
15,000
500
35,000

E



	
                          KCSULTIHt VASTE-LOAO CKAnACTCRISTICS



(a) TSS
Fe

Cu
pH
Oil & Grease
(t\\ cvno n
^Dj rres LLp

RAW
(UN-
TRF.ATED)
300
i ?nn

200
	
	 	




A
300
1 9on

200
	
_ 	 	


CONCENTRATIOf
AFTER
8
300
i onn

200
6-9



t««/l)(p»m)
TREATMENT TO 1
c
100


< 1.0
6-9
< 100



-EVEL
D
• 100

-------
                                   TABLE  V I I I - 2


                    WASTEWATER  TREATMENT COSTS AND RESULTING

                    WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT
 SUBCATEGORY   Oil or Gas  Fired  Plant

 PLANT SIZE

 PLANT AGE
500 MW
   .YEARS
PLANT LOCATION
                          COSTS OF TREATMENT TO ATTAIN SPECIFIED LEVELS
COST CATE90RY
TOTAL INVESTED CAPITAL
ANNUAL CAPITAL RECOVERY
ANNUAL OPERATING AMD MAINTENANCE
COSTS (EXCLUDIN9 ENER8YAND POWER)
ANNUAL CNER4Y AND POWER COSTS
TOTAL ANNUAL COSTS

COSTStfc) TOATTAIN LEVEL
A
80,000
13,000
Small
Small
13,000

B
300,000
48,800
60,000
1,000
109,800

c
300,000
48,800
80,000
2,000
130,800

0
-700,000
114,000
130,000
3,000
247,000

E




                          RESULTIN* WASTE-LOAD CHARACTERISTICS



(a) TSS
Fe
Cu
nM
P"
fin 1 ? Cloaca
ui j c* urt?ubc
(b) Free CL?

RAW
(UN-
TREATED)
300
1200
200







A
300
- 1200
200





CONCENTRATION
AFTER
B
300
1200
200
6-9




(m«/U(»m)
TREATMENT TO t
C
100

<1.0 ,
6-9

if
< inn



.EVEL
D
100
<1.0
<1.0
fi-Q

< ?n

0.5


E








(a) Low volume and metal  cleaning wastes combined
(b) Cooling Tower Slowdown
NOTE: TSS, Fe, and Cu,  raw wastes concentrations estimated  from Table A-V-20
      of Development Document  EPA 440/1-74029 a (12)
Level A - Flow Equalization
Level B - Equalization  of low  volume wastes, followed by  neutralisation
          to pH 6-9, skimming  of surface oil.  Metal cleaning  wastes combined
          with low volume wastes and neutralized without sludge removal.
Level C - Same as Level  B except meta!  cleaning wastes  neutralized, clarified
          with sludge removal  and discharged.
Level D - Equalization,  pK adjustment,  oil skimming, clarification, reacidi-
          fication.  Cooling tower blowa'own treated with  sulfite.
                               136

-------
blowdown is treated separately with sulfite to  remove  free
chlorine.

Costs and estimated effluent concentrations achieved for oil
and gas-fired plants are given in Table VIII-1 and VIII-2.

Detailed  model  description  for  Level  D  is given in the
following subsection.

Costs for Levels A, B, and C are roughly estimated from cost
experience with similar wastewater volumes and  compositions
in  other  industries  as  well as from steam electric power
plants.

Capital cost data for wastewater pretreatment facilities for
oil and gas-fired steam electric power plants discharging to
public sewerage systems are summarized in Table VIII-3.

 Table VII1-3. SUMMARY OF CAPITAL COSTS OIL AND GAS-
               FIRED PLANTS 25 MW PLANT
                       $ Per KW IGC
               Pretreatment Technology Level

Category                  A	B	<
Low Volume Wastes        0.38      1.20    1.20     1.60
Metal Cleaning Wastes    0.02      0.80    1.20     1.0
Cooling Tower Blowdown    NT        NT      NT      1.66
Boiler Blowdown           NT        NT      NT      0.54

TOTAL COST               O.UO      2.00    2.HO     U.8

                      500 MW Plant

                      $ Per KW IGC
               Pretreatment Technology Level


Category                    A	B  	C	 D
Low Volume Wastes          0.15      0.50     0.50    0.79
Metal Cleaning Wastes      0.01      0.10     0.10    0.20
Cooling Tower Blowdown      NT        NT       NT     0.31
Boiler Blowdown             NT        NT       NT     0.10

TOTAL COST                 0.16      0.6      0.6     l.UO

Note:    NA  not applicable to discharge to POTW
         NT  Not treated
                            137

-------
          A - Flow equalization.

          B - Equalization and neutralization of low
               volume wastes to pH 6-9, skimming of
              surface oil.  Metal cleaning wastes
              and neutralized.

           C - Same as Level B except metal cleaning
               wastes neutralized, clarified and
               discharged.  Provision is made for sludge
               removal.

           D - Equalization, pH adjustment, oil skimming,
               reacidification, clarification.  Cooling
               tower blowdown treated with sulfite.

Coal-Fired Plants

Coal-fired plants have ash pond  discharges,  air  pollution
control   wastewater,   coal   pile   runoff,   ion-exchange
regenerants, miscellaneous low volume wastes, cooling  tower
blowdown and metal cleaning wastes.

Estimated  wastewater  volumes  in  liters/day (GPD)  for the
plants sizes given are:

                                 25 MW            500 MW

o  Low Volume Wastes
   - Air Pollution Wastes       3800  (1000)    151,100  (10,000)
   - Ion Exchange Regenerants  liaOO  (3000)    154,000  (120,000)
   - Miscellaneous              3800  (1000)     15,100  (10,000)
o  Metal Cleaning Wastes         380  ( 100)     10,200  ( 2,000)
    o Cooling Tower      91,600(25000) 1,892,000(500,000)
       Blowdown

     o Area Runoff         3,800( 1000)     91,600 ( 25,000)

     o Ash Pond Discharge  3,800( 1000)     75,700( 20,000)

     o Boiler Blowdown

The low volume wastes  contain  primarily  acids  bases  and
suspended  solids.  The metal cleaning wastes contain acids,
bases, metals, and suspended solids.  Cooling tower blowdown
as discussed for oil and  gas-fired  plants  may  contain  a
variety   of   additives  but  for  purposes  of  this  cost
development is assumed to contain only free  chlorine.  Area
runoff  contains  acid,  suspended  solids and possibly some
metals. Ash pond discharges contain suspended and  dissolved
solids.
                            138

-------
The  minimum  level  for  pretreatments, defined as Level A,
consists of that level of technology which  is  equalled  or
exceeded  by most or all of the existing plants.  This level
involves some flow equalization and neutralization resulting
from the combination  of  waste  streams  of  differing  pH.
There  is  no  control or treatment of runoff. Expenditures,
both capital and operating are small.

Level B pretreatment involves  equalization  of  low  volume
waste  streams,  neutralization to pH of 6-9. Metal cleaning
wastes are stored in a large tank  or  small  pond  and  fed
slowly to the treatment system for low volume wastes.  There
is no control of area runoff.

Level  C pretreatment is the same as Level B except that the
metal  cleaning  wastes  are  neutralized,   clarified   and
discharged.   Provisions  is  made  for  the sludge removal.
Level  D  pretreatment  involves  technology  that  will  in
general meet the requirements of BPCTCA for direct discharge
to  surface  water.   For  this  level area runoff from coal
piles and ash transport water overflow  are  retained  in  a
pond  and fed continuously to a central pretreatment system.
Metal  cleaning  wastes  are  similarly  retained  and   fed
continuously  to the system.  The pretreatment system itself
is  described  in  a  following  subsection.   It   consists
primarily  of  a  tank for pH control and oil skimming and a
clarifier for suspended solids removal.

Costs and effluent quantities for the four treatment  levels
for  coal-fired  plants  are summarized in Tables VIII-4 and
VIII-5.

Capital cost data for wastewater pretreatment facilities for
coal-fired steam electric power plants discharging to public
sewerage systems are summarized in Table VIII-6.
Model Pretreatment Plants - Level C Technology

The  interim  final  pretreatment  standards  required   the
reduction  of  copper in the metal cleaning wastes to 1 mg/1
and of oil and grease to 100 mg/1 in  the  plant's  combined
discharge  to  the  POTW.  The equipment required to achieve
these standards are compatible to that required  to  achieve
Level C.  Although most, if not all, of the power plants can
comply  with  the  100 mg/1 of oil and grease requirement by
employing good housekeeping techniques, cost  data  for  oil
skimmer are included.

Model pretreatment plant costs have been developed for power
plants of 25 MW and 500 MW capacity of combined pretreatment
facilities for low volume and metal cleaning wastes.
                            139

-------
Estimates are for national average costs and do not consider
regional  differences  in construction costs.   All estimates
are based on the following technology: pretreatment  for  pH
adjustment to not less than 5, flow equalization so that the
instantaneous  peak discharge does not exceed five times the
monthly average flow rate, removal of oil  and  grease  from
the  plant's  combined  discharge to less than 100 mg/1, and
reduction of copper  to  1  mg/1  from  the  metal  cleaning
wastes.

Estimated  operating  costs  are  presented  for centralized
pretreatment facilities for each model plant size. Operating
costs include labor, fuel and power, chemiceils, maintenance,
residue removal and management.  Actual operating costs  may
vary  widely for those shown herein because of variations in
processes, degree of automation,  and  allocation  of  joint
labor costs.

Power  plants  sizes selected for model treatment plants are
25 MW and 500 MW.  The 25  MW  is  typical  of  the  smaller
plants  discharging  to  POTWs and listed in the ERGO survey
sample  (18).  Eighty-seven  and  one  half  percent  of  all
plants listed and discharging to POTWs have less than 100 MW
IGC, with 37.5 percent having less than 25 IGC.  Seventy-six
percent  of  the generating capacity discharging to POTWs is
in the size range between 2!>0 and 1000 MW, and  the  500  MW
plant is considered representative of this large size group.
For  the  25 MW model plant it was assumed that pretreatment
would be  a  batch  operation  with  low  volume  and  metal
cleaning   wastes  combined.   Treatment  would  consist  of
gravity separation  (skimming)  of  oils,  followed  by  lime
precipitation   of   metals,  sedimentation,  withdrawal  of
sludge, adjustment of pH to a neutral range, and  controlled
discharge.   Figure  VIII-1  is  a  flow diagram for a small
batch plant. For the 500 MW it was assumed that pretreatment
would be on a semicontinuous basis.  Metal  cleaning  wastes
would  be  stored  in an equalization tank, and bled into the
treatment operation at a  controlled  rate.   The  treatment
process  would  consist  of  oil  and grease skimming in the
equalization   tank,   lime   addition   in   the   reactor,
sedimentation  and clarification, and final adjustment of pH
before discharge to  the  public  sewer.   Sludge  from  the
clarifier  would  be  dewatered  on vacuum filters, with the
filtrate returned to the treatment plant  influent.   Figure
VIII-2 is a flow diagram of this process.

Cost Variances
Age  affects  the  cost of pretreatment in terms of cost per
unit  of  power  produced  primarily  because  age   affects

-------
                                    TABLE  VI11-4


                     WASTEWATER  TREATMENT COSTS AND RESULTING
                     WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT
  SUBCATEGORY   Coal  Fired  Plant
  PLANT SIZE    ?5 MW	

  PLANT AGE JLLUL. YEARS          PLANT LOCATION
                          COSTS OF TREATMENT TO ATTAIN SPECIFIED LEVELS
COST CATE90RY
TOTAL INVESTED CAPITAL
ANNUAL CAPITAL RECOVERY
ANNUAL OPERATING AND MAINTENANCE
COST* (EXCLUDING ENER8Y AND POWER)
ANNUAL EMEf.SY AND POWER COSTS
TOTAL AKNUAL COSTS

COSTS (}) TO ATTAIN LEVEL
A
20,000
3,250
Small
Small
3,250

B
75,000
12,200
15,000
Small
27,200

c
90,000
14,600
18,000
500
33,100

D
143,000
23,300
20,000
500
46,300

E




                           RESULTING WASTE-LOAD CHARACTERISTICS

PARAMETER

(a) TSS
Fe
Cu
oH
rn
nil X, Rvpflcp

/h^ Eroa fl o
\ D ) r ree ° ' 2

MAY;
TREATED)
300
1200
200








A
300
1200
200






CONCENTRATION
AFTER
B
300
1200
200
6-9





(mg/U (KM)
TREATMENT TO
C
100
	
<1.0
6-9


-------
                                    TABLE VI11-5


                      WASTEWATER  TREATMENT COSTS AND RESULTING

                     WASTE-LOAD CHARACTERISTICS FOR TYPICAL PLANT
  SUBCATEGORY

  PLANT SIZE

  PLANT AGE J|
              Coal  Fired  Plant
500 MW
    .YEARS
PLANT LOCATION
                           COSTS Of TREATMENT TO ATTAIN SPECIFIED LEVELS
F
COST CATE90RY
TOTAL INVESTED CAPITAL
ANNUAL CAPITAL RECOVERY
ANNUAL OPERATING AND MAINTENANCE
COSTS (EXCLUDING EMER9YANO POWEK)
AWHUAL tMERCY AKO POWER COSTS
TOTAL ANNUAL COSTS

COSTS ($3 TO ATTAIN LEVEL
A
100,000
16,300
Small
Small
16,300

B
350,000
57,000
70,000
2,000
129,000

c
350,000
57,000
93,100
2,500
152,600'

0
790,000
128,500
163,800
3,000
295,300

E




                           RESULTING WASTE-LOAD CHARACTERISTICS



(a) TSS
Fe
Cu
nU
pH

Ui I & brease
/u\ c ».«i ^ ••* n /^
(o) rree 112

RAW
(UN'
TRFA7EO!
300
1200
."'200




—



A
300
1200
200





1
CONCENTRATION
AFTER
B
300
1200
200
6-9


— — —


(m«/l) (pp«)
TREATMENT TO t
C
100

< 1.0
6-9

< 100




-EVEL
D
100
< 1.0
< 1.0
6-9


*• 20
Or
. 0


E









(a) Low volume and metal  cleaning wastes combined
(b) Cooling Tower Slowdown
NOTE: TSS, Fe, and Cu,  raw  wastes concentrations estimated  from Table A-V-20
      of Development  Document EPA 440/1-74029 a (12)
Level A - Flow Equalization
Level B - Equalization  of low volume wastes, followed by  neutralization
          to pH 6-9,  skimming of surface oil.  Metal cleaning  wastes combined
          with low volume wastes and neutralized without sludge removal.
Level C - Same as Level  B except metal cleaning wastes  neutralized, clarified
          with sludge removal  and discharged.
Level D - Equalization,  pH  adjustment, oil skimming, clarification, reacidi-
          fication.   Cooling  tower blowdown treated with  sulfite.
                                  142

-------
     Table VI11-6.  SUMMARY OF CAPITAL COSTS COAL FIRED PLANTS

                           25 MW Plant
                           $ Per KW IGC
                      Pretreatment Technology Level

Category                             A	B
- *J ij
Low Volume Wastes
Metal Cleaning Wastes
Cooling Tower Slowdown
Area Runoff
Ash Handling Wastes
Boiler Slowdown
TOTAL COST

Category
Low Volume Wastes
Metal Cleaning Wastes
Cooling Tower Slowdown
Area Runoffs
Ash Pond Discharges
Boiler Slowdown
TOTAL COST
NOTE: NA - Not applicabl
NT - Not treated
LEVELS OF PRETREATMENT
A - Flow Equalization
B - Equalization and neutral
0.78
0.02
NT
NT
NT
NT
0.80
500 MW Plant
A
0.19
0.01
NT
NT
NT
NT
0.20
e to discharge



ization of low
2.00
1.00
NT
NT
NT
NT
3.00

B
0.60
0.1
NT
NT
NT
NT
0.70
to POTW



volume
2.40
1.20
NT
NT
NT
NT
3.60

C
0.60
0.10
NT
NT
NT
NT
0.70




wastes to
2.58
1.2
1.66
0.19
0.19
0.10
5.92

D
0.92
0.2
0.31
0.05
0.05
0.10
1.63





    pH 6-9 skimming of surface oil.  Metal cleaning wastes
    combined with low volume wastes and neutralized without
    sludge removal.
C - Same as Level B except metal cleaning wastes neutralized,
    clarified and discharged.  Provision is made for sludge
    removal.
D - Equalization, pH adjustment, oil skimming, clarification,
    reacidification.  Cooling tower blowdown treated with
    sulfite.
                         143

-------
efficiency  and  plants  with lower effficiency will produce
more wastes per unit of power produced.   Plants  with  lower
efficiency  will  also  have lower utilization and therefore
produce fewer units of power in relation to their  installed
capacity.

Size

Size  is  related  to  age in that the older plants are more
likely to be smaller than the newer plants.   This  relation
likely  to  be smaller than the newer plants.  This relation
is shown in detail in the Development Document  (14).   Size
affects  the  cost of pretreatment as shown by the two plant
sizes, 25 MW and 500 MW.

Location

Location  affects   costs   of   pretreatment   because   of
differences in construction costs and labor rates in various
parts  of  the  U.S. and because the choice of the treatment
technology and the cost of  providing  that  technology  are
related to the availability of land.  For plants discharging
to public sewers, it may be assumed that they are located in
urbanized   areas,   where  land  availability  is  somewhat
limited.  The extent of that  limitation  will  vary  widely
depending on the size of the urban area, the location of the
plant  in that area, and the location of the area within the
U.S. Cost estimates are presented for two cases,  (1)  where
tankage  can  be  constructed at ground level, and (2)  where
tankage must be supported on a steel framework over existing
facilities because no other land is available.

COST ESTIMATES

Low Volume and Metal Cleanirig Wastes

Low volume wastes include all wastewaters other  than  those
for   which   specific   effluent   limitations   have  been
established.   Waste  sources  include  wet  air   pollution
control  systems,  water  treatment  systems, laboratory and
sampling  streams,  floor  drainage,  cooling  tower   basin
cleaning,  and blowdown from service water systems.  For the
purpose of cost estimating, metal cleaning wastes have  been
combined  with  low volume wastes as the most cost effective
method of handling these two  waste  sources.   Pretreatment
cost allottment to each type of waste has been estimated and
the  capital  costs  are given in Table VII1-9 and operating
costs are given in Table VIII-8.  This cost is  conservative
since  most  of  the  plants  only  need  to treat for metal
cleaning wastes.

Capital Costs
                            144

-------
                                                   LIME
                                                          ACID
01
    LOW  VOLUME WASTES
   200 gpd/MW


METAL CLEANING WASTES
  4  gpd/MW

BOILER SLOWDOWN
                                                               v
                                                 244  gpd/MW
                                                                           OIL & GREASE
                                                            TO SEWER & POTW
                                                                SLUDGE
                                                               (CaS04)
                       FIGURE VIII-1.  Model  Waste Pretreatment Plant 25 MW Generating Facility

-------
   CLEANING WASTES   (5.4 gpd/MW)
       BOILER TUBE -,
   BOILER FIRESIDE -

     AIR PREHEATER -
                         5.4 gpd/MW
                         EQUALIZATION
                             TANK
                                        OIL & GREASE
    LOW VOLUME WASTES

     WATER TREATMENT -i

AIR POLLUTION CONTROL-

        FLOOR DRAINS-

LABORATORY  & SAMPLING-
LIME
                                               CLARIFIER
                                              330  gpd/MW
                                     VACUUM
                                     FILTER
                   SEWER TO
                     POTW
           FIGURE VIII-2. Model Waste Pretreatment Plant 500  MW
               Generating Facility
                                 146

-------
Table VIII-9 provides estimated capital cost of pretreatment
plants for control of low volume and metal cleaning  wastes,
where   sufficient   land  is  available  to  construct  all
facilities at ground level.

If land availability is limited, treatment plant  components
may  have  to be stacked vertically and tankage supported on
steel  framework.   This  would  double  the  cost  of   the
installation of the equipment.

Operating Costs

Operating   costs  include  labor;  fuel,  power  and  other
utilities; supplies  (principally  chemicals);  maintenance;
removal and disposal of residues; and management.

Assumed  unit  costs for basic parameters of operating costs
are shown in the following table.

        Table VII1-7. ASSUMED UNIT COSTS

labor, per hour,
  including fringe benefits               $8.50
Electricity, per kwh                       0.04
No, 2 Fuel oil, per MM Btu                 2.50
Chemicals
  Lime, per ton                           30.00
  Sulfuric Acid, per ton                  50.00

Cost Data for Other Streams

Ash Transport Water

Ash transport water is  the  water  used  in  the  hydraulic
transport of bottom or fly ash.  Since the water serves only
as  a carrier of the ash, water quality is not a significant
consideration.  As  a  matter  of  fact,  a  high  level  of
suspended  solids  is  desirable  since  it  facilitates the
subsequent settling out and removal of the ash.

Settling basins are a  normal  component  of  ash  transport
systems.   They may be either of the mechanical clarifier or
natural lagoon  (ash pond) type.  Wet ash is removed from the
clarifiers and disposed off site.  The supernatent water  is
recycled to the process.  The only routine blowdown from the
system is the water removed with the wet ash.  Waste streams
result  from  overflows  during periods of precipitation and
for intermittant blowdown purposes.

At one of the plants visited, blowdown from a  recirculating
water  system  used  to  transport  fly  ash from oil fueled
                            147

-------
boilers was discharged to  the  POTW.    This  waste  can  be
combined with area runoff and could be treated together.

Costs  for  pretreatment  of  discharges  from ash transport
systems are estimated from the volume of the portion  coming
to the retention pond.

Boiler Slowdown

The  quality of boiler blowdown is generally higher than the
quality of the raw  water  source,  which  for  most  plants
discharging  to  POTWs  is  the  municipal water supply.  If
boiler blowdown is discharged to the waste stream,   it  will
tend  to  dilute  the  wastes  and  make  any treatment less
efficient.  Boiler blowdown should therefore be returned  to
the  plant  service water system, and in most plants this is
done.   Therefore,  no  costs  have   been   developed   for
pretreatment of this waste source.

Cooling System Wastes

Cooling system wastes are discharges of water that have been
used  to  cool the main condenser surfaces.   Cooling systems
are either of the once-through or recalculating type.  There
are no known plants  which  discharge  once-through  cooling
water  to  a  POTW.   Recirculating systems require blowdown
which becomes a waste source.

Levels of Treatment

Levels A  thru  C  treatment  for  cooling  system  blowdown
consists  of discharge to the POTW without pretreatment.  If
the only biocide or other cooling water  treatment  chemical
used  is  chlorine and the POTW does not impose restrictions
on chlorine  in  discharges  to  the  sewer,  cooling  water
blowdown  may  be  discharged without pretreatment.  In that
case the only  costs  will  consist  of  the  sewer  service
charges.   Level  D treatment for residual chlorine consists
of dechlorination and possible pH adjustment and  meets  the
requirements  of  effluent limitation guidelines for BPT for
direct discharge.   Level  D  treatment  for  cooling  water
system blowdown is shown in Figure VIII-3.

Capital Costs

Table  VIII-10  presents  estimates  for  capital  costs  of
pretreatment for cooling water system blowdown. These  costs
assume  that  chlorine  is  used as a biocide, that the POTW
requires removal of residual chlorine,  and  that  no  other
biocides or inhibitors unacceptable to the POTW are added to
the cooling water system.

-------
                        TABLE VIII-8
          OPERATING  COSTS-PRETREATMENT OF
        LOW VOLUME AND  METAL CLEANING WASTES
Installed Generating Capaci
Items
Operating Labor
Maintenance
Utilities
Water
Electric Power
Sewer Charge
Chemicals and
Supplies
Total
Anriual production, KWH

(1)
(2)

(3)
(4)
(5)

(6)


25 MW(7)
$1,700
3,000

200
40
500

15.000
$20,440
2.0xl08
500 MW(8)
$17,000
18,000

2,000
2,400
20,000

101,000
$160,400
4.0xl09
Notes to  Table VIII- 8

(1) 25 MW Plant -  4 hrs/wk   200  hrs/yr
   500 MW Plant -  40 hrs/wk  2000 hrs/yr

(2) 3% of capital  cost

(3) City water @ .60/100  gall

(4) 25 MW Plant -  5 kwh  x 200 hrs
   500 MW Plant -  30 kwh  x 2000  hrs

(5) Sewer service  charge  @ .30/1000  gal

(6) Lime 500 mg/1
    Sulfuric Acid  100 mg/1

(7) Design flow: Low volume  wastes:  5,000 gpd (from DD)
      Metal cleaning wastes: 25,000  gallons batch

(8) Design flow:   Low volume wastes  200,000 gpd (from DD)
      Metal cleaning wastes: 500 , 000 gal Ions batch

                          149

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Operating Costs

Operating  costs for pretreatment of cooling system blowdown
pretreatment consists of operating labor,  maintenance,  and
chemicals  for dechlorination.  They are summarized in Table
VIII-9.

Area Runoff

The area runoff subcategory includes  runoff  from  material
storage.

Coal  is  stored  in open piles and oil is stored in covered
tanks.  Materials storage therefore represents a significant
source of waste only for coal-fired plants.  And  since  the
burning of oil produces only about two percent of the amount
of  ash  produced  by  the  burning of coal, ash ponds are a
feature of coal burning plants primarily.  Material  storage
wastes   from   coal  piles  and  ash  ponds  are  therefore
applicable to coal burning plants only.

No plants discharging area runoff to POTWs were found in the
industry survey.

Level  D  treatment  for  coal  pile  runoff  and  ash  pond
overflows consists of neutralization and sedimentation.  Its
cost is a function of the size of the catchment area covered
by   the   coal  pile  and  the  ash  pond  and  the  design
meteorological  conditions  at  the  particular  site.   The
regulation (40 CFR 423.40)  require that treatment facilities
be  sized  to  treat  the  runoff  from  a  10-year, 24-hour
rainfall event  to  produce  an  effluent  having  suspended
solids  of  less  than 50 mg/1 and a pH between 6.0 and 9.0.
The applicable technology consists of lined ponds capable of
holding various volumes of runoff.

Capital Costs

For a 500 MW plant, a coal pile representing 90 days storage
will occupy 10 - 40 acres.   A retention  basin  designed  to
provide  one  hour  detention  at the maximum 10 minute rate
associated with a 10-year, 24 hour storm will generally meet
the effluent requirement.  Depending  on  location,  such  a
retention  basin  could  cost $27,000, $96,000, exclusive of
land, or $0.05-$0.19 per KW IGC.

Operating Costs

Operating costs for pretreatment facilities for runoff  from
coal  piles  and  ash  ponds  are  limited  to chemicals for
neutralizing.  It  is  estimated  that  chemicals  for  this
purpose  would  cost  $360  per  year  for a 25 MW plant and
                             150

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$7,200 per year for a 500 MW plant.  This corresponds  to  a
unit  cost  of  .0018 mils per KWH generated for a 90 percent
capacity factor.

The following table  (VIII-11) presents estimates for capital
costs of pretreatment plants for Level C  treatment  of  low
volume  and  metal  cleaning  wastes  for a coal-fired plant
where sufficient land is not available.

ULTIMATE DISPOSAL

Costs For Land Destined Solid Wastes

Waste treatment  processes  discussed  in  this  report  are
separation   techniques  which  produce  a  liquid  fraction
suitable for discharge to the public sewer or  reuse  within
the  plant  and  a  liquid  or  solid residue which requires
ultimate disposal.  Many of the  processes  produce  sludges
containing  between  0.5  and  5.0  percent  solids.   These
sludges are generally further dewatered at the site to 15 to
30 percent solids and then disposed off site.  The following
paragraphs discuss techniques and costs  of  dewatering  and
ultimate disposal applicable to steam electric power plants.

User  Charges  For  Sewer Service Of the twenty-three plants
visited in this study  only  15  percent  reported  separate
charges   for  sewer  service,  while  35  percent  reported
surcharges  on  their  water  bills   for   sewer   service.
Approximately  fifty percent did not report charge for sewer
service as they  were  municipal  utilities  whose  internal
billing systems did not allow for tracking of such charges.

The  average  charge  for  sewer service in this industry is
$0.06/1000 1 ($0.23/1000 gal).

Evaporation Ponds

Evaporation ponds are used by the industry as  a  method  of
ultimate  disposal,  particularly  in  the arid areas of the
southwestern United States.  The extensive land requirements
make it  unsuited  for  use  in  urban  areas  where  plants
discharging to POTWs are generally located.

Conveyance Off Site

The  cost  of this method of disposal is entirely related to
the distance  between  plant  and  disposal  site.    Alterte
methods  of  conveyance are trucks, railroads and pipelines.
Trucking is most economical for distances  under  50  miles.
Costs  are  of  the  order  of  ($.01-$0.13  per 1000 liter)
($0.05-$0.50 per 1,000  gallon)   miles  exclusive  of  final
disposal charges.
                             151

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     Table  VIII-9    ESTIMATED  CAPITAL  COSTS  CHEMICAL
             WASTES  PRETREATMENT  PLANT  LEVEL  C
                                   Installed Generating Capacity

Description                         25 MW                 500 MW

Equalization  Tank               $   28,000             $  115,000
Reactor                            	                  2,000
Clarifier                            2,000                  5,000
Pumps                               1,000                  4,000
Piping                              2,000                  5,000
     Subtotal, major equipment  J   33,000             |  131,000"
     Installation & Foundations     17,000                 65,000
     Instrumentation                 4,000                 14,000
     Subtotal, construction
       costs                    $   54,000             $  210,000
     Enginnering & Contin-
       gencies                      16,000                 60,000

Total, land not limited'        $   70,000             $  270,000
Premium for limited land
 construction                      20,000                 80,000
Cost per KW IGC                     $ 2.80                $ 0.54
Limited Land Premium                  0.80                  0.16
Estimated cost  allottment, unlimited land

     Low volume wastes                2.40                  0.60

     Metal  cleaning wastes            1.20                  0.10
                         152

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                 CONDENSER
                   1
                   COOLING
                    TOWER
MAKE-UP
SLOWDOWN  (1000
   .       gpd/MW)
                  r
                                SULFITE
                               LIME
                                     ACID
                MONITOR
                RESIDUAL
                CHLORINE
                  PH
     1
i
     CONTACT TANK
                                              SEWER
       FIGURE VIII-3.  Cooling Water System Slowdown Treatment
                         For Level D Pretreatment
                               153

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             Table  VIII-io   ESTIMATED CAPITAL COST
             COOLING WATER SYSTEM BLOWDOWN TREATMENT
       Description

Contact Tank
Chemical Feed System
Piping
     Subtotal, major equipment
     Installation & foundations
     Instrumentation
     Subtotal, construction costs
     Engineering 6 contingencies

     Total Cost

     Cost per KW IGC
Installed Generating Capacity
     25 MW        500 MW
    $10,000
      4,000
      6,000
    $20,000
     10,000
      2,000
    $32,000
      9,600

    $41,600

    $  1.66
   $40,000
    10,000
    25,000
   $75,000
    37,000r
     5,000
  $117,000
    35,000

  $153,000

  $   0.31
            Table  VIII-11    ESTIMATED OPERATING COSTS
             COOLING  WATER  SYSTEM BLOWDOWN TREATMENT
       Description

 Operating Labor
 Maintenance
 Chemicals
        Total
Insta]led^ Generating Capacity
   25~MW         500 MW
  $1,000
   1,200
     500
  $2,700
 $4,000
  6,000
 10,000
$20,000
                          154

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Landfills

Landfills  are  the  most common method of disposal of solid
wastes.  Costs of disposal at landfills range from $1 to  $9
per  metric ton ($2-10 per ton).  Recent federal regulations
require landfills  to  provide  leachate  control,  so  that
soluble  components  of  the wastes cannot cause groundwater
pollution.

ENERGY CONSIDERATIONS

In  contrast  to  the  effluent   guidelines   for   thermal
discharges,  the  promulgation of standards for pretreatment
is not expected to involve significant  energy  requirements
or  to  have a measurable impact on the energy production of
the  power  plant.   None  of  the  treatment   technologies
described  herein  affect  the  power  generating  cycle and
therefore do not require "retrofitting" to the  extent  that
the  performance  of  the  plant  is  impaired.  None of the
processes  involve  a  change  of   state   and   the   only
requirements  for  energy  are  for  possible pumping needs.
Even these needs are site dependent and  many  power  plants
may  find  it  feasible  to  install the equipment in such a
manner that repumping is not required.

For  estimating  purposes  it  has  been  assumed   that   a
pretreatment  plant  handling  low volume and metal cleaning
wastes from a 25 MW generating plant would have a  connected
load  of  5HP  and  that  a  similar  plant  for  the 500 MW
generating facility would have a connected load  of  30  HP.
Each  plant  would  operate  the equivalent of 800 hours per
year, at full connected load.  Under these  conditions,  the
energy  consumption  by the waste treatment facilities would
constitute about 0.02 percent of the generating capacity  of
the 25 MW generating plant and less than 0.01 percent of the
generating capacity of the 500 MW plant.

Land Requirement

Many of the stations potentially affected by this study tend
to  be  located  in  urbanized areas.  Land requirements are
important to  such  stations,  as  additional  land  may  be
difficult  to  purchase.    Estimated  land  requirements  to
install Level C technology are given in the table below:

           Station            Estimated
            Size                Land
           MW, IGC       Requirement, Acres

             10                  0.2
             25                  0.3
             37                  O.H
                            155

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            345                  1.1
            500                  1.6

Land estimates are based on usage of  tanks for equalization,
mixing, settling, etc.,   and  do  not  include  credits  for
stacked  construction.    They  contain  space allowances for
equipment,  pumps,   piping,   foundation   and   electrical
equipment  and  include   treatment equipment for low-volume,
metal cleaning and cooling tower wastes.   If basins are used
for equalization, etc.,   then  land  usage  is  expected  to
double.   If  stacked construction  is  employed,  then land
usage  is  expected  to   decrease  by  67   percent.    Land
requirements need not be a problem, as treatment modules can
be   erected   above  existing  generating  equipment   using
stacking procedures.
                            156

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                         SECTION IX

          BEST PRACTICABLE PRETREATMENT TECHNOLOGY
After careful  consideration  of  the  information  in  this
document  and the draft financial impact study, pretreatment
standards were developed.  The best practicable pretreatment
technology required to comply with these standards  includes
 (1)  oil  skimming  to  reduce oil and grease in the plant's
combined discharge to the POTW to less than  100  mg/1,  and
 (2)  lime  precipitation  to  reduce  copper  in  the  metal
cleaning wastes to less than 1 mg/1.

The  methodology  employed  in  the   development   of   the
pretreatment   standards  and  the  selection  of  the  best
practicable pretreatment technology is delineated below:

A detail survey was conducted to  determine  the  number  of
plants  affected by the pretreatment standards.  Some of the
plants  from  this  population  were  visited  and  sampled.
Plants   were   visited  to  determine  whether  significant
differences exist  between  these  power  plants  and  power
plants  which  discharge  directly  into  navigable  waters.
Further,   various   waste   streams   were   sampled   from
representative  power plants to determine the type and level
of pollutants.  In defining the characteristics  of  various
waste  streams,  data  from  the  site  visits  and sampling
program were used in conjunction  with  information  in  the
development document for effluent limitations guidelines for
this  industry  dated  October  1974 and other sources.  The
compatibility  of  each  raw   waste   characteristic   with
municipal   treatment   works   was  then  considered.   The
constituents of the wastewaters which should be  subject  to
limitations were identified.

The  control  and  treatment  technologies  were identified.
This included an identification of each distinct control and
treatment technology, including both  in-plant  and  end-of-
process  technologies, which is existent or capable of being
designed.   It  also  included  an  identification  of   the
effluent level resulting from the application of each of the
technologies.     In   addition,   the   non-water   quality
environmental impact, such as the effects of the application
of such technologies upon  other  pollution  problems,  were
identified.    The  energy  requirements  of  the control and
treatment technology were determined 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  reflected  the
application  of  the  recommended pretreatment technologies.
                            157

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In  identifying  such  technologies,  various  factors  were
considered.  These included the total cost of application of
technology,  the  age  and  size of facilities involved, the
fuel used, the mode of operations, the  engineering  aspects
of  the  application of various types of control techniques,
non-water quality environmental  factors  (including  energy
requirements) and other factors.

The  data  upon  which  the  above  analysis  was  performed
included EPA sampling and inspections,  consultant  and  EPA
reports, industry submissions, and other sources.

(2)  Summary of conclusions with respect to the general  unit
subcategory  (Subpart A), small unit subcategory  (Subpart B),
old   unit   subcategory   (Subpart   C)   and  area  runoff
subcategorization (Subpart D)  of the  steam  electric  power
generating point source category.

(i)  Categorization

It is determined that all the  facilities  discharging  into
POTW  should  be subject to the same pretreatment standards.
The standards for the general unit subcategory,  small  unit
subcategory  and  old  unit s;ubcategory are the same and the
pretreatment standards for the area  runoff  subcategory  is
different  because  of  the  nature  of its discharge.  Many
factors were  considered  in  this  determination,  but  the
largest contributing factors are  (1) the production process,
(2)   the  type and level of pollutants, (3)  the treatability
of wastewaters, and (4) the cost of the application of  such
technologies.

(ii)     Waste characteristics

There are two different types of  waste  produced  by  steam
electric  power  plants.   The  first  type  consists of the
chemical wastes which originate from different processes and
operations within a plant.  These wastes are highly variable
from plant to plant, depending on fuel, raw  water  quality,
processes  used  in  the plant and other factors.  The known
significant pollutants and pollutant properties  from  these
wastes  include  pH,  total  suspended solids, iron, copper,
nickel, zinc, chromium, oil arid grease, and chlorine.

The second type of waste consists of the waste heat produced
by the plant and disposed to  the  environment  through  the
cooling water system.

(iii)    Origins of wastewater pollutants

Wastewater streams from power plants can be classified  into
(1)   metal   cleaning  wastes,  (2) cooling system wastes,  (3)
                            158

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boiler blowdown,  (4) ash transport water, and  (5) low volume
waste.

Metal cleaning wastes are those  wastes  which  are  derived
from  cleaning  of metal process equipment.  These equipment
include,  but  are  not  limited  to,  boiler  tube,  boiler
fireside,  and  air  preheater.   Pollutants  and  pollutant
properties in these wastes include  oil  and  grease,  iron,
copper,  nickel,  zinc, total suspended solids, chromium and
pH.

All condenser cooling systems can be classified as (1)  once-
through or (2) recirculating.  Biocides such as chlorine  or
hypochlorites  are  usually  added  to  once-through cooling
water to minimize biological growth within the condenser and
may,  therefore,  be  discharged.   The  wastes   from   the
recirculating  cooling  system include chemical additives to
control growth of organisms  (such as chlorine  hypochlorites
and   organic  chromates) ,  chemical  additives  to  inhibit
corrosion  (such as organic phosphates,  chromates  and  zinc
salts),  and material present in the intake waters (but at a
much higher concentration due to evaporative loss).

Boiler blowdown wastes normally have  a  high  pH  and  high
dissolved  solids (except high pressure boiler) .  Phosphates
which are used to  precipitate  the  calcium  and  magnesium
salts are also found in boiler blowdown.

One  of  the  products  of the combustion of coal and oil is
ash.  These ashes are sometimes transported by  water  to  a
settling  pond  or basin.  Some or all of the water from the
settling pond or basin  may  be  discharged.   The  chemical
characteristic  of  ash  handling  wastewater is basically a
function of the fuel burned.  The pollutants  and  pollutant
properties in the ash handling wastes from coal fired plants
include TSS,  pH, iron, aluminum, mercury and oil and grease.
TSS, pH, oil and grease, and sometimes vanadium are found in
the ash handling wastes from oil fired plants.

Area runoff are the product of drainage from rainfall.   This
waste  stream  may  contain  TSS and oil and grease.   Runoff
from coal pile  may  also  contain  iron,  high  or  low  pH
(depending   upon  the  type  of  coal),  copper,  zinc  and
manganese.

Low volume wastes  include  ion  exchange  water  treatment,
water   treatment   evaporative   blowdown,  laboratory  and
sampling  streams,  floor  drainage,  cooling  tower   basin
cleaning,  ash  pollution  device  effluent  and any aqueous
power plant wastes which have  not  been  mentioned.    These
wastes contain primraily TSS and oil and grease.
                            159

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(iv)      Treatment and control technologies

Wastewater treatment  and  control  technologies  have  been
studied  for  this  industry  to  determine what is the best
pretreatment technology.

The following discussions of treatment technologies  provide
the  bases for the pretreatment standard.   These discussions
do not preclude the selection of other wastewater  treatment
alternatives  which  provide  equivalent or better levels of
treatment.

(a) Oil and Grease.  Oil skimmers have been demonstrated  to
reduce  oil  and  grease concentration to less than 20 mg/1,
far less than the limitation established here.  Most, if not
all, of the power plants can comply with this requirement if
they employ good housekeeping techniques.

(b) Copper.  The treatment of metal  cleaning  wastes  would
consist of oil and grease skimming in the equalization tank,
lime  addition  in  the  reactor  (to  attain  a pH level of
approximately 9) and  sedimentation  and  clarification  (to
achieve  a  total  suspended  solids  of 30 mg/1).  Effluent
concentrations of 1 mg/1 total copper are achievable by  the
application of this technology.  Numerous chemicals are also
removed by this treatment.  Pollutants significantly removed
by this treatment include nickel, zinc and chromates.

It is emphasized that in-piant measures to recycle and reuse
wastewater  to  minimize  discharge  to  municipal treatment
works are included as part of the  recommended  pretreatment
technology.

The  pretreatment technology described above for the removal
of copper requires disposal of the pollutants  removed  from
wastewaters in the form of sludge.  In order to insure long-
term protection of the environment, special consideration of
disposal  sites must be made.  All landfill sites where such
hazardous wastes are disposed should be selected  so  as  to
prevent   horizontal   and   vertical   migration  of  these
contaminants to ground or surface waters.   In  cases  where
geologic conditions may not reasonably ensure this, adequate
legal  and  mechanical precautions  (e.g., impervious liners)
should be taken  to  ensure  long  term  protection  to  the
environment  from  hazardous  materials.  Where appropriate,
the location of solid  hazardous  materials  disposal  sites
should  be permanently recorded in the appropriate office of
legal jurisdiction.

(v) Determination of incompatibility
                            160

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Characteristics  of  waste  streams  described  above   were
analyzed  for incompatibility with POTW.  Factors considered
in determining incompatibility include  (1)  susceptibility of
the pollutant to treatment by a secondary treatment  system,
and  (2) interference of the pollutant with the operation of
the POTW.

Copper, nickel and zinc from the metal cleaning wastes  were
found to be incompatible because (1)  they can interfere with
the  operation  of  the POTW,  (2) they may not be adequately
treated, and  (3) they pose a threat to the receiving  waters
beyond  and to plants grown on soil treated with sludge from
the POTW.  Pretreatment standard for copper from  the  metal
cleaning  wastes  of 1 mg/1 is imposed.  Limitations are not
imposed for nickel and  zinc  because  they  are  indirectly
controlled  through  the  regulation  of copper.  In certain
cases, copper may not be present  in  significant  quantity,
but   nickel   and  zinc  will  still  be  present  in  high
concentrations.  In such cases, it  will  be  necessary  for
individual  POTW  operators  to  regulate nickel and zinc to
levels which are achievable via lime precipitation.

Oil and grease from  power  plants  is  primarily  petroleum
based.  This type of oil and grease is less biodegradable in
secondary plants than oil and grease of vegetable and animal
origin.  Pretreatment standard of 100 mg/1 of oil and grease
is  imposed  to  ensure  (1)   the  proper  operation  of the
biological treatment system, (2) adequate treatment  by  the
POTW,  and  (3)  proper transport of wastes to the treatment
system.

Pretreatment standards other than those described above  and
the  general  standards  carried  over  from  40  CFR 128 is
determined not to be necessary at the present time.

(vi)      Cost estimates for control of wastewater pollutants

Cost  information  was  obtained  from  engineering   firms,
available  literature,  development  documents  for effluent
limitation guidelines (October, 1974)  for this industry, and
from plants contacted.  User charge data were obtained  from
power plants and POTW.

The  utilities affected by the regulation should have little
or no trouble in obtaining the  capital  necessary  for  the
construction  of  the  pretreatment  facilities.  The annual
revenue requirements are projected to increase the  cost  of
electricity by .11 mills/kwh at the affected plants.

(vii)    Energy   requirements   and    non-water    quality
environmental impacts.
                            161

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The  major  non-water  quality  consideration  which  may be
associated with the recommended pretreatment technologies is
the generation of  metals-bearing  solid  wastes.   In  most
cases, these wastes will be landfilled.

Other non-water quality aspects, including energy, noise and
air pollution, will not be perceptibly affected.
                            162

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                         SECTION X

                      ACKNOWL EDGMENTS
The  preparation of this report was accomplished through the
efforts  of  the  staff  of  the  Environmental  Engineering
Department,  Hittman  Associates,  Inc.,  Columbia, Maryland
under the overall direction of Mr. Burton  C.  Becker,  Vice
President,  operations.   Mr.  Dwight B. Emerson and Mr.  J.
Carl Uhrmacher shared direction of the  day-to-day  work  on
the program.

Mr. John Lum, Project Officer, Effluent Guidelines Division,
through  his  assistance, leadership, and advice has made an
invaluable contribution to the preparation of  this  report.
Mr.  Lum  provided  a careful review of the draft report and
suggested organizational, technical and  editorial  changes.
He  also  was  most  helpful  in making arrangements for the
drafting, presenting, and distribution of this report.

Mr.  Ernest  P.  Hall,  Jr.,  Assistant  Director,  Effluent
Guidelines  Division  and  Mr.  Harold  B.  Coughlin, Branch
Chief, Effluent Guidelines Division, Mr.  Devereaux  Barnes,
and Mr. Elwood Forsht, Project Officers, Effluent Guidelines
Division   offered   many  helpful  suggestions  during  the
program.

Appreciation is extended to the  Federal  Power  Commission,
Washington  D.C., and to Mr. Vick Saulys, Region V Office of
the  Environmental  Protection  Agency,  Chicago,  Illinois,
acknowledgment  to  James  Ferry-EPA/Office  of Planning and
Evaluation Garry F.  Otakie-EPA/Office  of  Water  programs,
Theordore  Landry-EPA  Region I, Fred Roberts EPA Corvallis,
Oregon Environmental Research Laboratory, Harvey  Lunenfeld-
EPA   Region  II,  Mr.  Robert  Burm-EPA  Region  VII,  Gary
Liberson-EPA  Office  of   Analysis   and   Evaluation   for
assistance  and  cooperation rendered to us in this program.
Additionally, we wish to thank Mr. John Rose  of  Daniel  P.
Frankfurt, PC, for his invaluable aid.

Also  our  appreciation  is  extended  to  the  staff of the
Environmental Engineering Department of Hittman  Associates,
Inc. for their assistance during this program. Specifically,
our thanks to:

Dr. Leon C. Parker, Senior Chemical Engineer
Dr. T. Goldshmid, Environmental Engineer
Mr. J. Carl Uhrmacher, Senior Chemical Engineer
Mr. Roger S. Wetzel, Environmental Engineer
Mr. Craig S. Koralek, Environmental Engineer
Mr. Kenneth G. Budden, Environmental Engineer
                            163

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Mr. Robert G. Matysek, Junior Chemical Engineer
Mr. Carroll E. Stewart, Chemical Engineer
Mr. Robert T. Brennan, Environmental Engineer
Mr. Efim M. Livshits, Environmental Engineer
Mr. Anthony T. Shemonski, Environmental Engineer
Mr. Werner H. Zieger, Environmental Engineer
Mr. Don s. Kondoleon, Environmental Engineer

The  physical  preparation of this document was accomplished
through the  efforts  of  the  secretarial  and  other  non-
technical staff members at Bittman Associates, Inc., and the
Effluent  Guidelines  Division.   Significant  contributions
were made by the following individuals:

Kaye Starr, Effluent Guidelines Division
Nancy Zrubek, Effluent Guidelines Division
Barbara A. White, Hittman Associates, Inc.
                            164

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                         SECTION XI

                         REFERENCES
1.  Barker, P.A., "Water Treatment for Steam Generating
    Systems", Industrial Water Engineering, March/April
    1975.

2.  City Council of Roswell, New Mexico, Ordinance No. 933,
    Industrial Waste Ordinance of The City of Roswell,
    New Mexico.

3.  Dean, John G., Bosqui, Frank L., and Lanouette,
    Kenneth H., "Removing Heavy Metals from Wastewater,"
    Environmental Science and Technology, Volume 6,
    No. 6, June 1972.

4.  Duffey, J,G. Gale, S.B., and Bruckenstein S.,
    "Electrochemical Removal of Chromates and Other
    Metals,"  Cooling Towers, Volume 2, pp. 44-50, 1975.

5.  Goldstein, Paul, "Control of CHemical Discharges for
    the Steam Electric Power Industry, NUS Corporation,
    Pittsburg, PA., Presented at Conference on Water
    Quality - Considerations for Steam Electric Power
    Plants, Atomic Industrial Forum, Inc., Phoenix, AZ,
    January 1975.

6.  Nail, Douglas E., "The Influence of EPA Guidelines
    on Treatment of Power Plant Wastes," Industrial
    Water Engineering, Volume 12, No. 6, December 1975 -
    January 1976.

7.  Office of Science and Technology, Electric Power
    and the Environment, August 1970.

8.  Patterson, J.W., et al, Wastewater Treatment Technology,
    Illinois Institute for Environmental Quality, Chicago,
    Illinois, August, 1971.

9.  Scott, David L., Pollution in the Power Industry,
    D.C. Heath and Co., Lexington, MA, 1973.

10. Stratton, Charles L., and Lee, G. Fred, "Cooling
    Towers and Water Quality," Journal of the Water
    Pollution Control Federation, Volume 47, No. 7,
    July 1975.

11. Teknekron, Inc., Water Pollution Control of the
    Steam Electric Power Industry - Assessment of the
    Costs and Capabilities of Water Pollution Control
                            165

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    Technology for the Steam Electric Power Industry,
    Volume 1, Berkley, CA, December 1975.

12. Teknekron, Inc., Water Pollution control of the
    Steam Electric Power Industry - Economic Impact of
    Water Pollution Control in the Steam Electric
    Power Industry, Volume 2, Berkeley, CA, December,
    1975.

13. Teknekron, Inc., Water Pollution Control for the
    Steam Electric Power Industry - Appendix, Volume 3,
    Berkeley, CAr December 1975.

1U. U.S. ENvironmental Protection Agency, Development
    Document for Proposed Effluent Limitations Guidelines
    and New Source Performance Standards for the Steam
    Electric Power Generating Industry, October, 197U.

15. U.S. Environmental Protection Agency, Office of
    Water Program Operations, Pretreatment of Pollution
    Introduced into Publicaliy Owned Treatment Works
    October 1973.

16. U.S. Environmental Protection Agency, Office of
    Water Program Operations, State and Local Pretreatment
    Programs  (Draft Federal Guidelines) Volume 1, August,
    1975.

17. U.S. Federal Power Commission, Statistics of
    Publicly Owned Electric Utilities in the United
    States 1970, Washington, D.C., February 1972.

18. U.S. Environmental Protection Agency, Office of
    Planning and Evaluation, Environmental Assessment
    of Alternative Thermal Control Strategies for the
    Electric Power Industry, December 197U.

19. Fair, G.M., Geyer, C.G., and Okum, D.A., Water
    and Wastewater Engineering, New York, NY, 1968.

20. U.S. Environmental Protection Agency, Development Document
    for Proposed Effluent Limitations Guidelines and Standards
    of Performance for the Machinery and Mechanical Products
    Manufacturing Category, June 1975.

21. Private communication with EPA Region II.

22. U.S. Department of Health, Education, and Welfare,
    Interaction of Heavy Metals and Biological
    Sewage Treatment Processes, Public Health Service,
    Division of Water Supply and Pollution Control,
    Cincinnati, Ohio  (May, 1975).
                            166

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23. D.J. Dube, Oilman D. Veith, and G.F. Lee, "Polychlorinated
    Biphenyls in Treatment Plant Effluent," Journal of the
    Water Pollution Control Federation, Volume 46, No. 5,
    May, 197U, pp. 966-72.

24. Pollution Abstracts, 5, (September, 1974) Abstract
    No. 74-0444-J.

25. F.D. Sebastian, T.D. Allen, and W.C. Laughlin, Jr.,
    "When Disposing of Sludge You May Want to Think Thermal,"
    Water and Wastes Engineering, Volume 11, No. 9,
    September, 197U, pp. 47-9.
                            167

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                        SECTION XII

                          GLOSSARY
Absolute Pressure.  The total force per unit  area  measured
above  absolute vacuum as a reference.  Standard atmospheric
pressure is 101,326 N/I12 (14.696 psi)  above absolute  vacuum
(zero pressure absolute).

Absolute  Temperature.  The temperature measured from a zero
at which all molecular activity ceases.  The  volume  of  an
ideal   gas   is   directly  proportional  to  its  absolute
temperature.  It is measured in °K  (°R) corresponding to  °C
+ 273 (°F + 459).

Anion.  The charged particle in a solution of an electrolyte
which carries negative charge.

A-thracite.   A  hard  natural  coal  of  high  luster which
contains little volatile latter.

Approach  Temperature.   The  difference  between  the  exit
temperature  of water from a cooling tower, and the wet bulb
temperature of the air.

Ash.  The solid residue following combustion of a fuel.

Ash Sluice.  The transport of solid  residue  ash  by  water
flow in a conduit.

Backwash.  Operation of a granular fixed bed in reverse flow
to wash out sediment and reclassify the granular media.

Bag  Filters.   A fabric type filter in which dust laden gas
is  made  to  pass  through  woven  fabric  to  remove   the
particulate matter.

Base.   A compund which dissolves in water to yield hydroxyl
ions  (OH-).

Base-Load Unit.  An electric generating  facility  operating
continously at a constant output with little hourly or daily
fluctuation.

Biocide.  An agent used to control biological growth.

Bituminous.   A  coal  of  intermediate  hardness containing
between 50 and 92 percent carbon.

Slowdown.  A portion of water in a closed  system  which  is
wasted in order to prevent a built-up of dissolved solids.
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Boiler.   A  device  in which a liquid is converted into its
vapor state by the action of heat.  In  the  steam  electric
generating industry, the equipment which converts water into
steam.

Boiler  Feedwater.   The  water  supplied  to a boiler to be
converted into steam.

Boiler  Fireside.   The  surface  of  boiler  heat  exchange
elements exposed to the hot combustion products.

Boiler  Scale.   An  incrustation  of salts deposited on the
waterside of a boiler as a  result  of  the  evaporation  of
water.

Boiler  Tubes.   Tubes  contained  in a boiler through which
water passes during its conversion into steam.

Bottom Ash.  The solid residue left from the combustion of a
fuel, which falls to the bottom of the combustion chamber.

Brackish Water.  Water having  a  dissolved  solids  content
between that of fresh water and that of sea water, generally
from 1000 to 10,000 mg per liter.

Brine.  Water saturated with a salt.

Bus  Bar.  A conductor forming a common junction between two
or more electric circuits.  A  term  commonly  used  in  the
electric  utility industry refer to electric power leaving a
station boundary.  Bus bar costs would refer to the cost per
unit of electrical energy leaving the station.

Capacity Factor.  The ratio of energy actually  produced  to
that  which  would have been produced in the same period had
the unit been operated continously rated capacity.

Cation.  The charged particles in solution of an electrolyte
which are positively charged.

Carbonate  Hardness.   Hardness  of  water  caused  by   the
presence  of  carbonates  and  bicarbonates  of  calcium and
magnesium.

Circulating Water Pumps.  Pumps which deliver cooling  water
to the condensers of a power plant.

Circulating  Water  system.   A system which conveys cooling
water from its source to the main condensers and then to the
point of discharge.  SYnonymous with cooling water system.
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Clarification.  A  process?  for  the  removal  of  suspended
matter from a water solution.

Clarifier.   A  basin in which water flows at a low velocity
to allow settling suspended matter.

Closed Circulating Water  System.   A  system  which  passes
water  through  the  condensers,  then  through  an articial
cooling device, and keeps recycling it.

Coal Pile Drainage.  Runoff from the coal pile as  a  result
of rainfall.

Condensate Polisher.  An ion exchanger used to adsorb minute
quantities  of cations and anions present in condensate as a
result of corrosion and erosion of metallic surfaces.

Condenser.  A device for converting a vapor into its  liquid
phase.

Construction.   Any  placement, assembly, or installation of
facilities or equipment (including contractural  obligations
to  purchase  such  facilities or equipment)  at the premises
where the equipment will be used, including preparation work
at the premises.

Convection.  The heat transfer mechanism  arising  from  the
motion of a fluid.

Cooling  Canal.   A  canal in which warm water enters at one
end, is cooled by contact with air, and is discharged at  te
other end.

Cooling Lake.  See Cooling Pond.

Cooling  Pond. A body of water in which warm water is cooled
by contact with air, and is either  discharged  or  returned
for reuse.

Cooling  Tower.   A  configured  heat  exchange device which
transfers  reject  heat  from  circulating  water   to   the
atmosphere.

Cooling  Tower  Basin.   A  basin located at the bottom of a
cooling tower for collecting the falling water.

Cooling Water System.  See Circulating Water System.

Corrosion Ihibitor.  A chemi.cal agent which  slows  down  or
prohibits a corrosion reaction.
                            170

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Counterflow.   A  process  in which two media flow through a
system in opposite directions.

Critical Point.  The temperature and pressure conditions  at
which  the  saturated-liquid and saturated-vapor states of a
fluid are identical.  For water-steam these  conditions  are
3208.2 psia and 705.U7°F.

Cycling Plant.  A generating facility which operates between
peak  load  and  base  load  conditions.   In this report, a
facility operating between 2000 and 6000 hours per year.

Cyclone Furnace.   A  water-cooled  horizontal  cylinder  in
which  fuel  is  fired,  heat  is released at extremely high
rates, and combustion is completed.  The hot gases are  then
ejected  into the main furnace.  The fuel and combustion air
enter tangentially,  imparting  a  whirling  motion  to  the
burning  fuel,  hence the name Cyclone Furnace.  Molten slag
forms on the cyclinder walls, and flows off for removal.

Deaeration.  A process by which dissolved air and oxygen are
stripped from water either by physical or chemical methods.

Deaerator. A  device  for  the  removal  of  oxygen,  carbon
dioxide and other gases from water.

Degasification.  The removal of a gas from a liquid.

Dejonizer.   A  process  for  treating  water  by removal of
cations and anions.

Demineralizer.  See Deionizer.

Demister.  A device for trapping liquid entrainment from gas
or vapor streams.

Dewater.  To remove a portion of the water from a sludge  or
a slurry.

Dew  Point.  The temperature of a gas-vapor mixture at which
the vapor condenses when it is cooled at constant humidity.

Diesel.   An  internal  combustion  engine  in   which   the
temperature  at  the  end  of  the  compression is such that
combustion is initiated without external ignition.

Discharge.  To release or vent.

Discharge Pjpe or Conduit.   A section  of  pipe  or  conduit
from  the condenser discharge to the point of discharge into
receiving waters or cooling device.
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Drift.  Entrained water carried from a cooling device by the
exhaust air.

Dry Bottom Furnace.  Refers to a furnace in which the ash is
collected as a dry solid in hoppers at  the  bottom  of  the
furnace, and removed from the furnace in this state.

Dry  Tower.  A cooling tower in which the fluid to be cooled
flows within a closed system.  This type  of  tower  usually
uses finned or extended surfaces.

Dry Well.  A dry compartment of a pump structure at or below
pumping level, where pumps are located.

Economizer.   A  heat  exchanger  which  uses  the  heat  of
combustion gases to raise the boiler  feedwater  temperature
before the feedwater enters the boiler.

Electrostatic Precipitator.  A device for removing particles
from  a  stream  of  gas  based  on the principle that these
particles carry electrostatic charges and can  therefore  be
attracted to an electrode by imposing a potential across the
stream of gas.

Evaporation.  The process by which a liquid becomes a vapor.

Evaporator.   A  device which converts a liquid into a vapor
by the addition of heat.

Feedwater Heater.  Heat exchangers in which boiler feedwater
is preheated by steam extracted from the turbine.

Filter Bed.  A device  for  removing  suspened  solids  from
water,  consisting of granular material placed in horizontal
layers  and  capable  of  being  cleaned  hyclraulically   by
reversing the direction of the flow.

Filtration.   The  process  of  passing  a  liquid through a
filtering medium for the removal  of  suspned  or  colloidal
matter.

Fireside  Cleaning.   Cleaning  of  the  outside  surface of
boiler tubes and combustion chamber refractories  to  remove
deposits formed during the combustion.

Flue   Gas.    The   gaseous  products  resulting  from  the
combustion process after passage through the boiler.

Fly Ash.  A portion of the non-combustible  residue  from  a
fuel which is carried out of the boiler by the flue gas.
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Fossil  Fuel.   A natural solid, liquid or gaseous fuel such
as coal, petroleum or natural gas.

Generation.  The conversion of chemical or mechanical energy
into electrical energy.

Heat Rate.  The fuel heat input  (in Joules or BTU)  required
to generate a KWH.

Heating  Value.  The heat available from the combustion of a
given  quantity  of  fuel  as  determined  by   a   standard
calorimetric process.

Humidity.  Pounds of water vapor carried by 1 Ib of dry air.

Ion.   A charged atom, molecule or radical, the migration of
which  affects  the  transport  of  electricity  through  an
electrolyte.

Ion  Exchange.   A  chemical  process  involving  reversible
interchange of ions between a liquid  and  a  solid  but  no
radical change in the structure of the solid.

Lignite.  A carbonaceous fuel ranked between peat and coal.

Makeup  Water  Pumps.   Pumps which provide water to replace
that lost by evaporation, seepage, and blowdown.

Mechanical Draft Tower.  A cooling tower in  which  the  air
flow  through  the  tower  is maintained by fans.  In forced
draft towers the air is forced through  the  tower  by  fans
located at its base, whereas in induced draft towers the air
is  pulled  through  the tower by fans mounted on top of the
tower.

Mill.  One thousandth of a dollar.

Mine-mouth,  Plant.   A  steam  electric  powerplant  located
within a short distance of a coal mine and to which the coal
is  transported  from  the mine by a conveyor system, slorry
pipeline or truck.

Mole.  The molecular weight of substance expressed in  grams
(or pounds).

Name Plate.  See Nominal capacity.

Natural  Draft Cooling Tower.  A cooling tower through which
air  is  circulated  by  natural  or  chimney   effect.    A
hyperbolic tower is a natural draft tower that is hyperbolic
in shape.
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Neutralization.  Reaction of acid or alkaline solutions with
the  opposite  reagent  until the concentrations of hydrogen
and hydroxyl ions are about equal.

New Source.   Any  source,  the  construction  of  which  is
commenced  after  the  publicated  of  proposed  section 306
regulations.

Nominal Capacity.  Name plate - design rating of a plant, or
specific piece of equipment.

Nuclear Energy.  The energy  derived  from  the  fission  of
nuclei  of heavy elements such as uranium or thorium or from
the fusion of the nuclei of light elements such as deuterium
or tritium.

Once-through Circulating Water System.  A circulating  water
system  which  draws  water from a natural source, passes it
through the main condensers and returns it to a natural body
of water.

Overflow.  (1)  Excess water over the normal operating  limits
disposed of by letting it flow out through a device provided
for  that  purpose;  (2) The device itself that allows excess
water to flow out.

Osmosis.  The process of diffusion of a solvent thru a semi-
permeable membrane from a solution of lower to one of higher
concentration.

Osmotic Pressure.   The  equilibrium  pressure  differential
across  a semi-permeable membrane which separates a solution
of lower from one or higher concentration.

Oxidation.  The addition of oxygen to  a  chemical  compund,
generally, any reaction which involves the loss of electrons
from an atom.

Packing   (Cooling  Towers) .  A media providing large surface
area for the purpose of  enhancing  mass  transfer,  usually
between a gas or vapor, and a liquid.

Precipitation.   A  pheonomenon that occurs when a substance
held in solution in a liquid phase passes  out  of  solution
into a solid phase.

Preheater   (Air).   A  unit  used to heat the air needed for
combustion  by  absorbing  heat   from   the   products   of
combustion.
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Peak-load Plant.  A generating facility operated only during
periods  of  maximum demand, in this report is is a facility
operating less than 2000 hours per year.

Penalty.  A sum to be forfeited,  or  a  loss  due  to  some
action.

Plant  Code  Number.   A  four-digit  number assigned to all
powerplants in the industry inventory  for  the  purpose  of
this study.

Plume   (Gas).   A  conspicuous trail of gas or vapor emitted
from a cooling tower or chimney.

Powerplant.   Equipment  that  produces  electrical  energy,
generally   by  conversion  from  heat  energy  produced  by
chemical or nuclear reaction.

Psychrometric.  Refers to air-water vapor mixtures and their
properties.  A psychrometric charg graphically displays  the
relationship between these properties.

Pulverized  Coal.   Coal  that  has been ground to a powder,
usually of a size where 80 percent  passes  through  a  #200
U.S.S. sieve.

Pump  Runout.  The tendency of a centrifugal pump to deliver
more than its design flow when the system  resistance  falls
below the design head.

Pyrites.   Combinations  of iron and sulfur found in coal as
FeS2.

Radwaste.  Radioactive waste  streams  from  nuclear  power-
plants.

Range.   Difference between entrance and exit temperature of
water in a cooling tower.

Rankine Cycle.  THe thermodynamic cycle which is  the  basis
of the steam-electric generating process.

Rank of Coal.  A classification of coal based upon the fixed
carbon on a dry weight basis and the heat value.

Recirculation  System.   Facilities  which  are specifically
designed to divert the major portion of  the  cooling  water
discharge back to the cooling water intake.

Recirculation.   Return  of  cooling water discharge back to
the cooling water intake.
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Regeneration.   Displacement from ion exchange resins of  the
ions removed from the process solution.

Reheater.   A  heat  exchange device for adding superheat to
steam which has been partially expanded in the turbine.

Relative Humidity.  Ratio of the  partial  pressure  of  the
water   vapor   to  the  vapor  pressure  of  water  at  air
temperature.

Reinlection.  To return a flow or portion of  flow,  into  a
process.

Reverse Osmosis.  The process of diffusion of a solvent thru
a  semi-perable membrane from a solution of higher to one or
lower concentration, affected by raising the pressure  of  a
more concentrated solution to above the osmotic pressure.

Reduction.   A  chemical reaction which involes the addition
of electrons to an ion to decrease its positive valence.

Saline Water.   Water containing salts.

Sampling Stations.  Locations where several flow samples are
tapped for analysis.

Sanitary Wastewater.  Wastewater  discharged  from  sanitary
conveniences of dwellings and industrial facilities.

Saturated   Air.   Air  in  which  the  water  vapor  is  in
equilibrium with the liquid water at air temperature.

Saturated Steam.  Steam at the temperature and  pressure  at
which the liquid and vapor phase can exist in equilibrium.

Scale.    Generally  insoluble  deposits  on  heat  transfer
surfaces which inhibit the passage  of  heat  through  these
surfaces.

Scrubber.  A device for removing particles and/or objection-
able gases from a stream of gas.

Secondary Treatment.  The treatment of sanitary wastes water
by    biological    means   after   primary   treatment   by
sedimentation.

Sedimentation.  The process of subsidence and deposition  of
suspended matter carried by a liquid.

Sequestering  Agents.   Chemical compunds which are added to
water systems to prevent the formation of scale  by  holding
the insoluble compunds in suspension.
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Service  Water  Pumps.   Pumps providing water for auxiliary
plant heat exchangers and other uses.

Slag Tap Furnace.   Furnace  in  which  temperature  is  high
enough  to  maintain  ash  (slag) in a molten state until it
leaves the furnace through a tap at the  bottom.   The  slag
falls   into   the   sluicing   water   whwere   it   cools,
disintegrates, and is carried away.

Slimicide.  An agent used to destroy or control slimes.

Sludge.  Accumulated solids separated from a  liquid  during
processing.

Softener.  Any  device  used  to remove hardness from water.
Hardness in water is due mainly  to  calcium  and  magnesium
salts.    Natural   zeolites,   ion   exchange  resins,  and
precipitation processes are used to remove the  calcium  and
magnesium.

Spinning Reserve.   The power generating reserve connected to
the  bus  bar  and ready to take load.  Normally consists of
units operating at less than full load.  Gas turbines,  even
though  not  running, are considered spinning reserve due to
their quick start up time.

Spray Module  (Powered Spray Module).  A water cooling device
consisting of a pump and spary nozzle or nozzles mounted  on
floats  and  moored in the body of water to be cooled.  Heat
is transfered principally  by  evaporation  from  the  water
drops as they fall through the air.

Station.   A  plant  comprising one or several units for the
generation of power.

Steam  Drum.   Vessel  in  which  the  saturated  steam   is
separated  from  the  steam-water mixture and into which the
feedwater is introduced.

Supercritical.  Refers to boilers designed to operate at  or
above  the  critical point of water 22,100 kn/m2 and 374.0°C
(3206.2 psia and 705.4°F).

Superheated  Steam.   Steam  which  has  been  heated  to  a
temperature  above  that  corresponding  to  saturation at a
specific pressure.

Thermal Efficiency.  The  efficiency  of  the  thermodynamic
cycle  producing work from heat. The ration of usable energy
to heat input expressed as percent.
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Thickening.  Process of increasing  the  solids  content  of
sludge.

Total  Dynamic  Heat (TDH).  Total energy provided by a pump
consisting  of  the  difference  in  elevation  between  the
suction  and dischage levels, plus losses due to unrecovered
velocity heads and friction.

Turbidity.  Presence of suspended matter such as organic  or
inorganic  material plantkton or other microscopic organisms
which reduce the clarity of the water.

Turbine.   A device used to convert the energy of  steam  or
gas  into rotation mechanical energy and used as prime mover
to drive electric generation.

Unit.  In steam electric generation, the  basic  system  for
power  generation  consiting  of a boiler and its associated
turbine and generator with the required auxiliary equipmet.

Utility.  Public utility.  A company,  either  investorowned
or  publicly  owned  which provides service to the public in
general.  The electric  utilities  generate  and  distribute
electric power.

Volatile Combustion Matter.  The relatively light components
in  a  fuel  which  readily  vaporize  at  a  relatively low
temperature and which when combined or reacted with  oxygen,
give out light and heat.

Wet Bottom Furnace.  See slag-tap furnace.

Wet  Bulb  Temperature.   The  steady-state,  nonequilibrium
temperature reached by a small mass of water immersed  under
adiabatic conditions in a continous stream of air.

Wet  Scrubber.   A  device for the collection of particulate
matter from a gas stream and/or absorption of noxious  gases
from the stream.

Zeolite.   Complex sodium aluminum silicate materials, which
have ion exchange  properties  and  were  the  original  ion
exchange materials before synthetic resins were processed.
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                         APPENDIX A

          STATISTICAL ANALYSIS OF HISTORICAL DATA
Effluent pretreatment standards achievable by steam electric
power  plants  discharging  their  wastewater effluents into
publicly-owned treatment  facilities  were  determined  from
statistical  analysis  of  historical  data  describing  the
pollutants concentration over extended periods of time.   Of
the   three   plants  analyzed  only  one  provides  partial
pretreatment which includes flow equalization, oil  removal,
and  settling.  The remaining two plants discharge untreated
waste.  This appendix  describes  the  statistical  approach
used and presents results of that analysis.

The  statistical  analysis  was based on the assumption that
the data are normally distributed, that is, their  frequency
of   occurrence   is   fully   defined  by  two  statistical
parameters: The mean X and the standard deviation  s.    Each
set of data representing the variation of concentration of a
particular  pollutant  in treated effluent was statistically
examined to determine the mode of normal  distribution  that
best describes its frequency of occurrence.  Both arithmetic
and   logarithmic   modes   of   normal   distribution  were
considered.  The degree of fit of the data to any particular
mode was  determined  by  calculating  the  coefficients  of
skewness  and of kurtosis.  The former measures the symmetry
of the distribution diagram  and  the  latter  measures  the
height  of  the  peak  of  the diagram relative to that of a
normal curve.  A  perfect  fit  to  normal  distribution  is
indicated   by   a   zero  coefficient  of  skewness  and  a
coefficient of kurtosis of three.

If neither the  arithmetic  nor  the  logarithmic  modes  of
normal  distribution describe the frequency of occurrence of
a data set, a modified  logarithmic  mode  was  employed  to
"force"  the  data  into  normal distribution.  This mode is
referred to as  the  three-parameters  logarithmic  type  of
normal  distribution.   It  is  assumed  that deviation from
normal distribution occurs in the  tails  of  the  frequency
curve  where  the  probability  of  occurrence  is very low.
Thus, it is assumed that deviation of data from the  perfect
logarithmic  mode  of  normal  distribution  is due to small
sample size.  The overall effect of  this  deviation  is  to
increase the variance of the data set.  The three-parameters
approach  is  designed to remove this deviation in the tails
by adding or subtracting a constant number, smaller than the
first element of the data set, to each member of the sample.
The exact value of the constant is determined by iterating a
series of mathematical expressions designed  to  generate  a
                            179

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zero  coefficient  of  skewriess and a value of approximately
three for the coefficient of kurtosis.

The mathematical treatment of data  was  carried  out  by  a
computer  program.   Each  set of data was initially read by
the computer which sorted elements in ascending order.   The
computer  then  calculated  the  first  four moments and the
coefficients of skewness and kurtosis for each of the  three
modes  of normal distribution.  The statistical coefficients
of  the  three-parameters   logarithmic   mode   of   normal
distribution  were  determined  by  initially  assigning  an
arbitrary constant to be added to each element of  the  data
set.   The  computer  calculated the coefficient of skewness
and determined from its value  whether  the  deviation  from
normal  distribution  occurred at the lower or upper tail of
the diagram.  A deviation in the lower tail was indicated by
a negative value and the computer proceeded to correct it by
adding  to  each  of  the  elements  half  of  the  arbitary
constant.   A positive coefficient of skewness was corrected
by subtracting half of  the  constant.   This  was  repeated
until  a  zero  coefficient  of  skewness was obtained.  The
computer then calculated  the  percent  cumulative  of  each
element in the series and converted it to standard deviation
expressed as probit (standard deviation plus five).

Based  on  the  values  of  the coefficients of skewness and
kurtosis the mode of normal distribution that best described
the distribution of the data set was selected and  the  data
were  subjected to a least squares analysis as a function of
the corresponding probits to determine the  coefficients  of
regression    (slope,    intercept,   and   coefficient   of
determination).  The regression line was used  to  determine
the 99 percent confidence upper limits.

Table   A-1  lists  the  mathematical  expressions  used  to
calculate the various  statistical  parameters.   These  are
shown in Tables A-2 to A-6 for various pollutants discharged
from three pants.  Each of these tables shows the calculated
values  of  the  first four moments, and the coefficients of
skewness and kurtosis, for  each  of  the  modes  of  normal
distribution.  Also  shown in these tables are the constants
used  to  normalize  the  distribution  of  the  data,   the
coefficients    of   regression    (slope,   intercept,   and
coefficient of determination), and the 99 percent confidence
limits.  Plots of the best fit  data  and  their  regression
lines  are  shown  in  Figures A-1 to A-19.  The statistical
parameters of the best fit data are summarized in Table A-7.
The historical data analyzed are listed in Table A-8.

Water usage data listed in Section V  of  this  report  have
also  been  statistically  analyzed  by  the  three modes of
normal distribution.  The results are listed  in  Table  A-9
                            180

-------
and  plotted  in  Figures A-20 to A-23.  In all of the water
usage categories examined,  the  distribution  of  the  data
could  be  normalized by the three parameter approach.  This
is indicated by  the  numerical  values  calculated  by  the
coefficients of determination which measure the "goodness of
fit" of the regression line.  The values were always greater
than 90 percent.

The  water  usage  data  were  also plotted on log-log paper
against production rate to determine  the  effect  of  plant
size  on  the quantity of water used.  These plots are shown
in  Figures  A-2U  to  A-27  and  the  coefficients  of  the
statistical  regression analysis expressed in logarithms are
shown in Table A-10.  The results indicate that based on the
available data, there is no correlation between water  usage
in  each of the categories and production rate, as indicated
by  the  low  values  calculated  for  the  coefficients  of
determination.
                            181

-------
       Table A-l.   MATHEMATICAL EXPRESSIONS FOR  DETERMINATION

                        OF  STATISTICAL PARAMETERS
First moment            m  = -  / „  X^  (mean)
                           1    n    2   -2
                                 ~*
                                        -
Second moment           m = -   J~*  X^  - X   (variance)
                                     *                    3
Third moment            m = -   \~*'  K  - ^ *   >  X, + 2X
                        3  n   / ,    i   n     /_,  i

                               1=1              i=l



                                n              n               n

                           1   V-   V4   4 77"   V* Y3 x 6  V"2  V Y2   TV"4
Fourth moment           m^= -   ) j   X^  - — X   / _, X^ + —  X    / . X^ - 3X

                               1=1              1=1             i=l




Coefficient of skewness  7i  = m
Coefficient of kurtosis  Y±  - m4
                             ~7T

                             m2
 Probit                  Q =   /   e   dt

                            x*
/OO    i2

   el	
   o 	

   277
                        X = t -  Co + C»t + C2f     ^

                                1 + djt + d2t^ + d3t
                        P = X + 5
                           182

-------
Slope
                                 DRAFT
                                            n       n
                                                   Ev*
                                              y.   2-»
                       i-  x=
                                 EX*
                                      1
                 n
Intercept
                      a2 = P -
                             P = i=l
Coefficient  of determination
Li=l
i=l
                                             1=1-
     X1
     n

     C
- the value of element i of a data set.   X-f=Xj  for  arithmetic mode,
  Xj=log X-j for logarithmic mode, and X^log (X-j  +  a)  for three-
  parameters mode  of normal distribution, where a is the added or
  subtracted constant.

- number of elements in a data set

- 2.515517           d} - 1.432788

- 0.802853           d2 - 0.189269

- 0.010328           d3 - 0.001308

  e(Q)< 4.5 x ICT"
                          183

-------
                Table A-2;  STATISTICAL  ANALYSIS  OF  HISTORICAL  DATA  (MG/L)
Plant No. 7308 Wastewater Source: Retention Pond
Pollutant
Mode of Normal
Distribution
Statistical
Parameter
Mean •
Variance
Third Moment
Fourth Moment
Coeff. of Skewness
Coeff. of Kurtosls
Correction Constant
Slope
Intercept
Coeff. of Determination
992 Confidence Limit
Iron
Arithmetic
4.75
0.68
0.28
0.77
0.49
1.63

1.88
-4.67
0.91
6.67
Logarithmic
4.86
0.005
0.00
0.00
0.4
1.51





Nickel
Arithmetic
2.40
51214.64^
—
—
1.45^
3.18(1)





Logarithmic
1.73
0.09^
0.035(l)
0.026^'
1.21(1)
2.87{1)





Three
Parameters
Logarithmic
1.3
0.60(1>
0.00
0.780)
o.oo '0)
2.160)
-0.92
1.150)
-4.170)
0.970)
3.1
Silver
Arithmetic
0.04
1.680)
-2.530)
6.640)
-1.15<1>
2.330)

1.58(D
-3.52(1)
0.33 0)
0.07
Logarithmic
0.04
0.020)
-o.oosO)
0.0020)
-1.750)
2.330)





CO
.Ł»
          (1) calculated with data x 100

-------
                  Table A-3.  STATISTICAL ANALYSIS OF HISTORICAL DATA (MG/L)
00
en
Plant No. 7308 Vtestewater Source: Cooling Tower Basin
Pollutant
>^^ Mode of Normal
^~>^D1str1bution
Stat1sticaV""s\>^
Parameter ' ^""^-^^^^
Mean
Variance
Third Moment
Fourth Moment
Coeff. of Skewness
Coeff. of Kurtosls
Correction Constant
Slope
Intercept
Coeff. of Determination
99J Confidence Limit
Iron
Arith-
metic
5.27
10.55
12.70
255.14
0.37
2.29

4.26
-16.0
0.96
12.83
Loga-
rithmic
3.92
0.12
-0.02
0.03
-0.63
2.05





Copper
AH th-
metlc
0.34
2535.43
190480.68
...
1.49
3.23





Loga-
rithmic
0.64
0.24
0.14
0.17
1.22
2.96





Three
Para-
meters
Loqa-
•Mthmic
0.58
0.72
0.00
1.31
0.00
2.48
-0.04
1.19
-5.21
0.87
0.8
Chromium
Arith-
metic
2.90
605.02(1)
20240. 16
--_
1.36(1)
3.760)





Loga- ,
Mthmlc
2.08
0.12(1)
(U
0.000
0.03(1)
0.14<"
2.23^





Three
Para-
meters
Loga-
rithmic
2.03
0.15«>
U)
0.00
0.05C)
0.00(l)
2.29(')
-0.14
0.507("
-1.25
0.96^
2.93
(1) calculated with data x 100

-------
                   Table A-3. STATISTICAL ANALYSIS  OF HISTORICAL DATA (MG/L) 1C.ON!JNUED!

Mode of Normal
^^Distribution
StatisticaT^1^^^
Parameter ^"-'v^^
Mean
Variance
Third Moment
Fourth Moment
Coeff. of Skewness
Coeff. of Kurtosis
Correction Constant
Slope
Intercept
Coeff. of Determination
99* Confidence Limit
Lead
Arith-
metic
0.29
543.1
11025.36
712419.5
0.87
2.41





Loga-
rithmic
0.2
0.15
-0.02
0.04
-0.29
2.02





Three
Para-
meters
Loga-
rithmic
0.33
0.08
0.00
0.01
0.00
2.00
0.05
0.37
-0.41
0.93
0.45
Zinc
Arith-
metic
3.9
36S961.o(*)
--.-
--.
,.H(2)
4.5,(a)





Loga-
rithmic
1.38
(2)
0.33
o.,a'21
o.K121
10.94U
(2)
2.34





Three
Para-
meters
Loga-
rithmic
0.8
1.09<«
(2)
0.0
(2)
2.51
o.o-('}
2.1 <2)
-0.4
1.39^)
-5.31^)
0.98(2)
3.51
pH(D
Arith-
metic
6.4
20.5<3)
t-i)
-129.5
1640.0^)
-,.3,(3)
3.89l3>





Loga-
rithmic
6.3
0.001 .
(3)
0.00
O.OG<3)
-,.5(3)
-3.43<3)





Three
Para-
meters
Loga-
rithmic
6.4
o.oO)
0.0(3)
0.0^)
0.0(3)
-4.03^3)
8.02
0.01.(3)
2.07(3)
0.78(3)
6.4
CO
cr>
              (1) pH units


              (2) calculated with data x 100


              (3) calculated with data x 10

-------
                     Table A-4.  STATISTICAL  ANALYSIS OF HISTORICAL  DATA (MG/L)
Plant No. 8696 Wastewater Source: Derolnerallzer
Pollutant
Mode of Normal
*""**»>[) i s trlbu 1 1 on
Statlstical^^^
Parameter ^^^^^
Kean
Variance
Third Moment
Fourth Moment '
Coeff. of Skewness
Coeff. of Kurtosls
Correction Constant
Slope
Intercept
Cceff. of Determination -
991 Confidence Limit
PH(1)
Arith-
metic
5.5?
14.13
26.64
319.44
0.50
1.60





Loga-
rithmic
4.161
0.10
-0.001
0.02
-0.05
1.78





Three
Para-
meters
Loga-
rithmic
4.26
0.09
0.00
0.015
0.00
1.71
0.204
0.35
-1.09
0.93
9.26
Suspended Sol Ids
Arith-
metic
32.67
4053.73
737828.37

2.86
10.35





Loga-
rithmic
12.02
0.26
0.19
0.27
1.42
3.86





Three
Para-
meters
Loga-
rithmic
'8.55
0.70
0.00
1.68
0.00
3.40
-3.54
0.96
-4.09
0.92
97.56

BOOS
Arith-
metic
2.53
3.21
3.1
23.98
0.54
2.32

2.07
-7.82
0.94
6.89
Loga-
rithmic
0.25*
0.18
-0.05
0.08
-0.75
2.60





COO
Arith-
metic
28.83
424.58
12699.82
718259.0
1.45
3.98





Loga-
rithmic
23. 441
0.07
0.007
0.015
0.39
2.69





Three
Para-
meters
Loga-
rithmic
22.27
0.11

0.03
0.00
2.95
-3.65
0.38
• -0.64
0.94
28.20
00
          (1) prt units

-------
                       Table A-5. STATISTICAL A:;.".YSIS OF HISTORICAL DATA  (MG/L)
oo
00
Plant No. 8696
Pollutant
^^ Mode of Normal
^\^t)istribution
Statistical^>^^
Parameter ^^"-^
Mean
Variance
Third Moment
Fourth Moment
Coeff. of Skewness
Coeff. of Kurtosis
Correction Constant
Slope
Intercept
Coeff. of Determination
99J Confidence Limit
Wastewater Source: Cooling tower blowdown
PH
-------
                      Table A-C.   STATISTICAL  ANALYSIS  OF HISTORICAL DATA (MG/L)
00
10
Plant No. 8392 Nastewater Source: Cooling tower Boiler
Pollutant
Mode of Normal
— -s^Distrlbution
Statistical ^^^
Parameter ^"^^^^
Mean
Variance
Third Moment
Fourth Moment
Coeff. of Skewness
Coeff. of Kurtosis
Correction Constant
Slope
Intercept '
Coeff. of Determination
991 Confidence Limit
Chroma te
Arithmetic
14.94
7.31
32.69
394.28
1.65
7.37





Logarithmic
14.46
0.05
0.0002
0.0001
0.66
5.63





Three
Parameters
Logarithmic
14.53.
0.01
0.00
0.001
0.00
5.37
-5.62
0.12
0.34
0.77
16.24
Phosphate
Arithmetic
17.1
13.98
10.86
569.44
0.20
2.90





Logarithmic
16.59
0.009
-0.0003
0.0002
-0.36
2.82





Three
Parameters
Logarithmic
16.51
0.002
0.00
0.00
0.00
-3.10
19.99
0.05
1.31
0.97
17.18


-------
           Table A-7.  STATISTICAL PARAMETERS SUMMARY FOR BEST FIT DATA (MG/LJ
Cooling Tower Slowdown
Source (Plant 8596)
Parameter
PH
Suspended Solids
BOOS
COO
Source
Parameter
Chromate
Phosphate
Statistical
Mode
Arithmetic
3-Farameter
Logarithmic
3-Paraneter
Concentration
Mean
7.46
13.59
2.36
26.40
991
Confidence
Limit
8.11
15.39
3.85
27.55
Cooling Tower Slowdown
(Plant 8392)
3-parameter


14.53


16.24


Source Cooling Tower Basin
(Plant 7308)
Parameter
Fe
Cu
Cr
Pb
Zn
PH
Statistical
Mode
AH thmetlc
3-pararceter
3-parameter
3-parameter
3-parameter
3-parameter
Concentration
Mean
5.27
0.58
2.03
0.33
0.8
6.4
99t
Confidence
Limit
12.83
0.80
2.93
0.45
3.23
6.4
Source Retention Pond
Parameter
Fe
N1
A9

AM thmt-tlc
3-parameter
Arithmetic

4.75
1.3
.0.04

6.67
3.1
0.03
Demlneral 1 zer •
(Plant 8696)
Statistical
Mode
3-parameter
3-parameter
Arithmetic
3-parameter
99!
Concentration Concentration
Mean Limit
4.26 9.26
8.55 97.56
2.53 6.89
22.27 28.20
Boiler
(Plant 8392)


3-parameter



16.51 17.78

vo
o

-------
           ljbJe_A-8.  HISTORICAL  DATA  (MG/L)
 Plant  No.  8696

 Cooling  Tower Slowdown

 pH        7.27. 7.94, 7.08,  7.4,  7.26, 7.72, 7.14,  7.5,  7.33.
           7.72, 7.4, 7.97,  7.14,  7.25. 7.35, 7.23.  7.65,  7.39,
           7.98. 7.35

 SS        11.0, 23.0, 23.0,  14.0,  15.6, 12.0, 7.2,  13.  11.6,
           16.0, 19.6, 13.5,  17.6,  11.0, 12.0, 8.4

 BOD-       2.7, 3.0, 1.0, 2.1,  3.7,  3.7, 3.3, 3.8, 3.9.  2.9,
    5       3.2,2.5,2.2,1.9,1.6,1.3,1.4,1.6

 COD       24.0, 29.0, 27.0,  12.0,  33.0. 30.0, 30.0, 31.0.
           2.2, 24.0, 23.0,  21 .0,  20.0

.  Oemineralizer Backwash

 pH        1.0, 5.77, 1.95,  3.23,  2.86, 3.26, 9.52,  2.16,  6.42,
           2.72, 10.10, 9.87,  11.65, 9.8, 1.72, 12.0,  2.7,  2.78

 SS        96.0, 8.4, 11.0,  9.6,  5.6, 6.4, 4.0, 5.2, 19.0,
           10.8, 3.6, 8.6,  84.0,  8.0, 264.0, 6.4, 4.8

 BOD,       4.7, 0.3, 0.2. 0.7,  0.9,  1.0, 2.7, 5.8, 6.2,  3.2,
    5       3.0,2.8,3.3,2.1,3.8,1.6,0.8;

           22.0, 19.0, 21,0.  7.0,  13.0. 22.0, 22.0,  24.0.,
           •~ ~  39.0, 13.0,  71.0,  57.0, 18.0, 20.0, 83.0,
 Chromate   16,0, 24,0, 18.0,  14.0,  16.0, 14.0, 14.0,  14.0,  14.0,
           12.0, 10.0, 14.0,  14.0,  16.0, 14.0, 14.0.  16.0,  16.0,
           14.0

 Bojler
 Phosphate 15.0, 18.0,  16.0,  26.0,  19.0. 15.0, 18.0,  13.0,  20.0,
          17.0, 14.0,  12.0,  10.0,  20.0, 13.0, 21.0,  19.0,  18.0

Plant No.  7308

Retention  Pond

Fe        4.0,  179.0, 4.0, 6.0, 5.0

N1        1.35,  6.9, 1.1, 1.72, 0.95

Ag        0.05,  0.05, 0.05. 0.02


Cooling Tower Basin_

Fe        11.4,  7.25. 5.75. 1.0. 7.5,  3.5,  4.5. 1.3

Cu        0.05,1.35.0.12,0.1,0.1

Cr        2.0,  4.0, 4.0, 8.6, 1.1,  0.55, 1.5, 1.5

Pb        0.25,  0.75, 0.05, 0.6, 0.25,  0.25,  O'.IS, 0.06

Zn        7.85,  18.75, 0.8, 0.7, 0.45,  1.75,  0.54, 0.41
                      191

-------
   500
   100
    50
Ł



-------
co
         ^  100
Ł



<
I—

Q

Q
         c;
         O
             50
             10
               3.0
                    4.0
                                              I
5.0

PROBITS
6.0
7.0
             FIGURE A-2. Normal Distribution  Diagram  for  Phosphates  Concentration
                                  In  Boiler Slowdown  (Plant  8696)

-------
           50
            10
to
-pi
o

Q
LU

I—I
_l

-------
     100
    cr.
   Q
   UJ
   M
   OL
   O
        3.0
6.0
                                 PROBITS
FIGURE  A-4.Normal Distribution Diagram  for  COD  Concentration
         In Wastewater From Demineralizer(Plant  8696)
                        195

-------
   50
 CT)
•=1
Q
Q
UJ
ex.
O
   10
     3.0
4.0
  5.0

PROBITS
6.0
7.0
FIGURE  A-5, Normal Distribution  Diagram for Supser.ded Solids Concentration
                   In Cooling  Tower  Slowdown (Plant 8696)

-------
IO
        <
        t—

        Q
        o:
        o
             3.0
4.0
 5.0

PROBITS
6.0
7.0
           FIGURE  A-6.  Normal Distribution Diagram  for  COD  Concentration  In
                     Cooling Tower Slowdown  (Plant  8696)

-------
            50
            10
vo
00
        Q

        Q
        LU
        M
        a:
        o
                                                                       ©
               3.0
4.0
 5.0

PROBITS
6.0
7.0
         FIGURE   A-7. Normal Distribution  Diagram  for  Chromates  Concentration In
                             Cooling Tower Slowdown  (Plant  8392)

-------
             10
10
<Ł>
          E

         
-------
ro
8
      ~   9.0

-------
07
2   3
M
s:
K
O

2   2
     3.0
4.0
 5.0


PROBITS
6.0
                                                           7.0
    FIGURE A-10. Normal  Distribution Diagram for BODs
      Concentration  in  Demineralizer Backwash
                  (Plant 8696)

                          201

-------
     io'
  <
  m

  o
     10
        3.0
4.0
  5.0

PROBITS
6.7
7.0
FIGURE A-ll, Normal Distribution Diagram for  Normalized Nickel

           Concentration in Retention Pond  (Plant  No.  7308)

                        202

-------
  10'
Q
LJ
   10
    3.0
4.0
  5.0  ',
PROBITS
6.0
7.0
 FIGURE .A-12.Normal  Distribution Diagram for  Normalized
    Chromium Concentration in Cooling Tower Basin
                 (Plant No.  7308)
                     203

-------
 •10'
<
h-
<
c:
o
   10
                     o
    3.0
4.0
J	

  5.0

PROBITS
6.0
7.0
   FIGURE  A-13.  Normal  Distribution Diagram for Normalized

       Lead Concentration in Cooling Tower Basin (Plant  No.  7308)
                        204

-------
   10'
<  10'
Q
UJ
M
an
o
   10
    3.0
4.0
 5.0
PROBITS
6.0
7.0
   FIGURE A-14. Normal  Distribution Diagram for Normalized
  Zinc Concentration  In  Cooling  Tower Basin (Plant No. 7308)
                       205

-------
   8.0
crt
   7.0
   6.0
Q
Ul

2  5-0
_j
<
«r-

o
z

   4.0
       3.0
4.0
5.0
                                 PROBITS
6.0
7.0
     FIGURE  A-15.  Normal  Distribution Diagram  for  Iron
        Concentration  in  Retention Pond (Plant  No.  7308)
                         206

-------
              O)
              S
                 12.0
                 10.0
                  8.0
ro
o
             o
             o
                  6.0
             Di
             o
                  4.0
                  2.0
                     3.0
4.0
                                                  5.0

                                               PROBITS
6.0
7.0
                   FIGLFRE A-16.  Normal Distribution  Diagram for Iron  Concentration
                             In  Cooling Tower  Basin  (Plant No. 7308)

-------
ro
8
           200
         o
         o
150
         ef.
         O

         O
         UJ
         
-------
           8.0
           6.0
     Q
     UJ
     OL
     O
           2.0
                                      ©
              4.0
  I


  5.0

PROBITS
6.0
FIGURE ' A-18.  Normal Distribution  Diagram for Silver
    Concentration Retention Pond  (Plant  No.  7308)
                      209

-------
Q

Q
LU

t—i
_l
=C


O
   10
       3.0
4.0
5.0
6.0
7.0
                                PROBITS
   FIGURE  A-19. Normal Distribution Diagram  for  Normalized
      topper Concentration Cooling Tower  Basin  (Plant No. 7308)
                      210

-------
                   Table A-9.
STATISTICAL  ANALYSIS OF WAT.ER USAGE
       DATA  BY CATEGORY
Mater Usage
Category
Mod* of W-*!
\. Oistribct'3-i
Statistical ^\^
Parameter \^
Mean
Variance
Third Moment
Fourth Moment
Coefficient of Skemss
Coefficient of Kurtosis
Correction Constant
Slope
Intercept
Cofff. of Deterafnaefon
941 Confidence Unit
Once-through
Cooling Hater
,10'
Arithmetic
29.43
228.14 '
3681.88
(U
l.OS
3.08





Logarithmic
(2)
1.42
0.10
0.00
0.00
0.33
2.12





Three
Parapeters
Logaritrvric
(?)
1.23
0.10
0.00
0.00
0.00
2.01
-7.86
2.66
0.13
0.99
2.37
^ecirc-'ating
Coolin9 Water
Arithwt'C
6.2
37.50
231.39
3060 0
1.01
2.18





Logan thmic
(?)
O.S9
0.17
0.03
0.06
0.41
2.06





Three
Paraveters
logarithmic
(?)
0.49
0.25
0.00
0.16
0.00
2.43
-0.51
4.07
0.00
0.92
0.86
Boiler Nake-^p
Hater
Arithmetic
370
(1)
(1)
(1)
2.2
6.98





Looaritnr.ic
(2)
1.99
0.55
0.05
0.74
0.12
2.49





Three
Parameter
Logarithmic
(2!
1.99
0.59
0.00
O.89
0.00
2.S8
-1.20
8.04
0.00
0.96
4.23
Oerii'era'lzer
Hater
Arithmetic
74.28
(1)
(1)
(1)
1.95
5. OS





Looarithntc
(?)
1.38
0.36
0.20
0.36
0.94
2.81






Three
Paraaieter
(.Maritime
1.12
0.73
0.00
1.45
0.00
2.70
-4.31
10.97
0.00
0.97
1.31
(1) Greater than 10*
(2) Expressed as logarithms

-------
                   Table  A-10.   STATISTICAL  PARAMETERS  OF  REGRESSION  ANALYSIS
                         OF  WATER USAGE AGAINST  PRODUCTION  RATE
^"^^^ Water Usage
^\Category
Statisti cal^"^^
Parameter ^\.
Slope
Intercept
Coefficient of
Determination
Standard Error of
Estimated Water
Use on Production
Rate
Standard Error
of Intercept
Standard Error
of Slope
Once-through
Cool ing Water
-0.13
6.14
0.11
0.23
0.17
0.94
Recirculating
Cooling Water
0.06
3.08
0.00
0.77
2.09
0.37
Boiler Makeup
Water
-0.92
7.1
0.47
0.57
1 .45
0.26
Demineralizer
Water
0.03
1.52
0.00
0.65
1.76
0.31
ro

-------
     10'
     10
cs
     10
       3.0
4.0
  i

 5.0
PROBITS
6.0
                                                           7.0
   FIGURE A-23. Normal Distribution Diagram for Normalized
                   Ion Exchange Water Usage Data
                         213

-------
  10'
Ul
03
«=c
ct:
ui
H-
«t
  IOJ
      3.0
4.0
                                 I
 5.0
PROBITS
6.0
7.0
         FIGURE A-20  .  Normal  Distribution  Diagram for  ;Normalized
                      Once-Through Usage Data
                          214

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        10"
      cr
      *r:
      oo
        10'
        10
           4.0
5.0           6.0

     PROBITS
7.0
FIGURE A-22.   Normal  Distribution  Diagram for Normalized
            Boiler Makeup Water Usage  Data
                       215

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     10'
100
cu
cc:
LU
    10'
    10'
    102
       3.0
                     e
4.0
 5.0

PROBITS
6.0
7.0
 FIGURE  A-21.  Normal Distribution  Diagram for  Normalized
             Cooling Water Usage  Data
                         216

-------
    10'
    10'
to
    10
                    I      I
                90  Percent  Confidence  Limit
Regression Li
                     90
   i     i
                                       i     i
       10'
        10°                10b

         PRODUCTION RATE (MWH)
10
     FIGURE A-27. Demineralizer Water Usage vs. Annual Production
                               Rate
                           217

-------
                  I    I
                  I     I
x   10'
3
                     nt c

                     *-
                                       o
                                  •^ L7'n" ©
    10-
       10"


FIGURE A-24
                  I	I
                  I	J
I
      io5              io6               io7
        PRODUCTION RATEX
            (MWH)
Once-Through Cooling  Water  Use vs. Annual
  Production Rate
                      218

-------
    10'
    10
 00
 5   10-
     10'
     10
                    rcent  ConfldenceJ-lmlt	_
95 Percentj.
                95  Percent_ Confidence ^U	^
        I
I
       10
      10a              10°

     PRODUCTION RATE (MWH)
                    10'
FIGURE A-25
Recirculating Cooling Water  Use  vs.  Annual
  Production Rate
       219

-------
  10'
   10'
LU
cr
«=c
10'
   10
                                           10
                                                           10
                                                               ,7
      FIGURE  A-26
                       PRODUCTION RATE (MWH)
                  Boiler Makeup Water Use vs. Annual  Production
                         Rate
                              220

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                         APPENDIX B

                       WATER GLOSSARY
Acid-washed  activated  carbon  - Carbon which has been con-
    tacted  with  an  acid  solution  with  the  purpose  of
    dissolving ash in the activated carbon.

Acidity  - The quantitative capacity of aqueous solutions to
    react with hydroxyl ions.  It is measured  by  titration
    with  a  standard  solution of a base to a specified end
    point.  Usually expressed  as  miligrams  per  liter  of
    calcium carbonate.

Acre-foot - (1)  A term used in measuring the volume of water
    that is equal to the quantity of water required to cover
    1  acre  1  ft deep, or 43,560 cu ft.  (2) A term used in
    sewage treatment in measuring the volume of material  in
    a  trickling filter.  One acre-foot contains 43,cu ft of
    water.

Activated Carbon - Carbon which is treated by  high-tempera-
    ture  heating  with steam or carbon dioxide producing an
    internal  porous  particle  structure.    The   internal
    surface  area  of granular activated carbon is estimated
    to be about 3,600 sq ft gr.

Activiated  Sludge  Treatment   Process   -   (See   Sludge,
Activated).

Adsorption  -  The  adhesion  of  an extremely thin layer of
    molecules (of gas, liquid) to  the  surfaces  of  solids
    (granular  activiated  carbons  for instance)  or liquids
    with which they are in contact.

Adsorption isotherms  (activated carbon)  - A  measurement  of
    adsorption  determined  at  a  constant  temperature  by
    varying the amount of carbon used or  the  concentration
    impurity in contact with the carbon.

Advanced  Waste  Treatment - Any treatment method or process
    employed following biological treatment  (1)  to  increase
    the  removal of pollution load. (2)  to remove substances
    that may be  deleterious  to  receiving  waters  or  the
    environment.  (3)  to  produce  a  high-quality effluent
    suitable for reuse in any specific manner  or  for  dis-
    charge  under  critical  conditions.   The term tertiary
    treatment is commonly  used  to  denote  advanced  waste
    treatment methods.
                            221

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Aerated  Pond - A natural or artificial wastewater treatment
    pond in which mechanical or  diffused  air  aeration  is
    used to supplement the oxygen supply.

Aeration  -  The  bringing about of intimate contact between
    air and liquid by one of the following methods  spraying
    the  liquid  in the air, bubbling air through the liquid
    (diffused aeration) agitation of the liquid  to  promote
    surface absorption of air (mechanical aeration).

Aerobic - Living or active only in the presence of oxygen.

Aerobic  Biological  Oxidation - Any waste treatment or pro-
    cess utilizing aerobic organisms in the presence of  air
    or  oxygen,  as the agent for reducing pollution load or
    oxygen demand or organic substances in waste.  The  term
    is used in reference to secondary treatment of wastes.

Algicide   -  Chemicals used in the control of phytoplankton
    (algae) in bodies of water.

Alkalinity - The capacity of water to  neutralize  acids,  a
    property  imparted by the water's content of carbonates,
    bicarbonates,  hydroxides,  and  occassionally  borates,
    silicates, and phosphates.  It is expressed in miligrams
    per liter of equivalent calcium carbonate.

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

Anaerobic Biological Treatment -  Any  treatment  method  or
    process  utilizing anaerobic or facultative organisms in
    the absence of air  for  the  purpose  of  reducing  the
    organic  matter  in wastes or organic solids settled out
    of wastes commonly referred to as anaerobic digestion or
    sludge digestion when applied to the treatment of sludge
    solids.

Anaerobic Waste  Treatment  -  Waste  stabilization  brought
    about  through  the  action  of  microorganisms  in  the
    absence of air or elemental oxygen.  Usually  refers  to
    waste treatment by methane fermentation.

Anion Exchange Process - The reversible exchange of negative
    ions  between  functional  groups  of  the  ion exchange
    medium and the solution in which the solid is  immersed.
    Used  as  a  wastewater treatment process for removal of
    anions, e.g., carbonate.

Anionic Surfactant - An ionic type  of  surface-active  sub-
    stances  that has been widely used in cleaning products.
                            222

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    The hydrophilic group of  these  surfactants  carries  a
    negative charge in washing solution.

Apparent  Density  (Activated  Carbon) - The weight per unit
    volume of activated carbon.

Appurtenances, Sewer - Structures, devices  and  appliances,
    other  than pipe or conduit, which are integral parts of
    a sewerage system: such as manholes flush tanks, surface
    inlets.

Aquifer - A subsurface geological  structure  that  contains
    water.

Assimilative  Capacity  -  The capacity of a natural body of
    water to receive:  (a)  wastewaters  without  deleterious
    effects:  (b) toxic materials, without damage to aquatic
    life or humans who consume the  water;  (c)  BOD  within
    prescribed dissolved oxygen limits.

Autooxidation  -  A chemical system which will oxidize auto-
    matically when some set of conditions are  met  such  as
    temperature, oxygen supply, moisture content, etc.

Backflow  Prevention  - A system designed to protect potable
    water from wastewater contamination which could occur if
    wastewater pressure exceeds potable water pressure  over
    a cross-connection where one or more check valves fail.

Backsiphonage - The flowing back of contaminated or polluted
    water from a plumbing fixture or cross connection into a
    water  supply line, due to a lowering of the pressure in
    such line.

Backwashing - The process of cleaning a rapid sand or  mech-
    anical filter by reversing the flow of water.

Bacterial  Examination - The examination of water and waste-
    water to determine the presence, number,  and  identifi-
    cation of bacteria. Also called bacterial analysis.

Baffles  -  Deflector  vanes,  guides,  grids,  gratings, or
    similar devices constructed or placed in  flowing  water
    or  sewage  to  (1)  check or effect a more uniform dis-
    tribution of velocities; (2) absorb energy;  (3)  divert
    guide,  or  agitate  the  liquids;  and   (1)  check eddy
    currents.

Banks, Sludge - Accumulations on the bed of  a  waterway  of
    deposits of solids of sewage or industrial waste origin.
                            223

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Bed   Depth  (Activated  Carbon)   -  The  amount  of  carbon
    expressed in length units which is parallel to the  flow
    of the stream and through which the stream must pass.

Bioassay  - (1)  An assay method using a change in biological
    activity as  a  qualitative  or  quantitative  means  of
    analyzing  a  materials reponse to industrial wastes and
    other wastewaters by using viable organisms or live fish
    as test organisms.

Biochemical Oxygen Demand (BOD)  - (1)  The quantity of oxygen
    used in the biochemical oxidation of organic matter in a
    specified time, at a specified  temperature,  and  under
    specified conditions (2)  standard test used in assessing
    wastewater strength.

Biocides  -  Chemical  agents with the capacity to kill bio-
    logical life forms.  Bactericides, insecticides,  pesti-
    cides, etc.  are examples.

Biodegradable  -  This  part  of organic matter which can be
    oxidized by  bioprocesses,  e.g.,  biodegradable  deter-
    gents, food wastes, animal manure, etc.

Biological Wastewater Treatment - Forms of wastewater treat-
    ment  in which bacterial or biochemical action is inten-
    sified to stablize, oxidize, and  nitrify  the  unstable
    organic matter present.  Intermittent sand filters, con-
    tact  beds,  trickling  filters,  and  activated  sludge
    process are examples.

Blowoff - A  controlled  outlet  on  a  pipeline,  tank,  or
    conduit  which  is  used  to  discharge water or accumu-
    lations of material carried by the water.

Branch -  (1)  A special form of vitrified sewer tile and cast
    iron pipe used for making  connections  to  a  sewer  or
    water  main.  They are called T, Y, T-Y, double Y, and V
    branches according to their respective shapes.  (2)  Any
    part of a piping system other than a main.

Broad-Crested  Weir  -  A weir having a substantial width of
    crest in the direction parallel to the direction of flow
    of water over it.  This type of weir supports the  nappe
    for   an  appreciable  length  and  produces  no  bottom
    contraction of the nappe.  Also called widecrested weir.

Buffer - Any of certain combinations of  chemicals  used  to
    stablize the pH values or alkalinities of solutions.
                            224

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Bulking  Agent  -  A  fine solid material which is sometimes
    added to a wastewater stream to produce clarification or
    coagulation by adding bulk to the solids.

Bulking, Sludge - A  phenomenon  that  occurs  in  activated
    sludge  plants  whereby  the  sludge  occupies excessive
    volumes and will not concentrate readily.

Cake, Sludge - The material resulting  from  air  drying  or
    dewatering sludge (usually forkable or spadable).

Calibration  - The determination, checking, or rectifying of
    the graduation of  any  instrument  giving  quantitative
    mea surements.

Carbon  Column  A  - A column filled with granular activated
    carbon whose primary function is  the  preferential  ad-
    sorption of a particular type or types of molecules.

Carbon  Tetrachloride  Activity  -  The  maximum  percentage
    increase in weight of a bed of  activated  carbon  after
    air   saturated  with  carbon  tetrachloride  is  passed
    through it at a given temperature.

Catalyst -  A  substance  which  accelerates  or  retards  a
    chemical   reaction  without  undergoing  any  permanent
    changes.

Cation  Exchange  Process  -  The  reversible  exchange   of
    positive  ions  between  functional  groups  of  the ion
    exchange medium and the solution in which the  solid  is
    immersed.   Used  as  a wastewater treatment process for
    removal of cations, e.g. calcium.

Cationic Surfactant - A surfactant in which the  hydrophilic
    group   is  positively  charged;  usually  a  quaternary
    ammonium salt such as cetyl trimethyl  ammonium  bromide
    (CeTAB) ,  C1j>H3_3N  +  (CH_3) 3^ Br Cationic surfactant as a
    class  are  poor  cleaners,   but   exhibit   remarkable
    disinfectant properties.

Cesspool  -  An  underground  pit  into  which raw household
    sewage or other untreated liquid waste is discharged and
    from which the liquid seeps into the surrounding soil or
    is  otherwise  removed.    sometimes   called   leaching
    cesspool.

Chamber  Detritus  -  A detention chamber larger than a grit
    chamber  usually  with  provision  for  moving  sediment
    without  interrupting  the  flow  of liquid.  A settling
    tank of short detention period  designed,  primarily  to
    remove heavy settleable solids.
                            225

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Chamber/  Flowing-Through  - The upper compartment of a two-
    story sedimentation tank.

Chamber, Grit - A small detention chamber or an  enlargement
    of  a  sewer  designed to reduce the velocity of flow of
    the liquid, to permit the  separation  of  mineral  from
    organic solids by differential sedimentation.

Chelating  Agents  -  A chelating agent can attach itself to
    central metallic atom so as to form a heterocyclic ring.
    Used to make ion-exchange more  selective  for  specific
    metal ions such as nickel, copper, and cobalt.

Chemical  Analysis - The use of a standard chemical analyti-
    cal procedures  to  determine  the  concentration  of  a
    specific pollutant in a wastewater sample.

Chemical  Coagulation  -  The  destabilization  and  initial
    aggregation of colloidal and  finely  divided  suspended
    matter by the addition of a floe-forming chemical.

Chemical  Oxygen Demand (COD) - (1)  A test based on the fact
    that all organic compounds, with few exceptions  can  be
    oxidized  to  carbon  dioxide and water by the action of
    strong oxidizing agents under acid  conditions.  Organic
    matter  is converted to carbon dioxide and water regard-
    less of the biological assimilability of the substances.
    One of the chief limitations  is  its  ability  to  dif-
    ferentiate  between  biologically  oxidizable and biolo-
    gically inert organic matter.  The  major  advantage  of
    this  test  is the short time required for evaluation (2
    hr). (2) The amount of oxygen required for the  chemical
    oxidation of organics in a liquid.

Chemical  Precipitation - (1) Precipitation induced by addi-
    tion of chemicals, (2) the process of softening water by
    the addition of lime and soda ash as the precipitants.

Chemisorption - Adsorption  where  the  forces  holding  the
    adsorbate   to  the  adsorbent  are  chemical  (valance)
    instead of physical (van der Waals).

Chlorination - The  application  of  chlorine  to  water  or
    wastewater,  generally  for the purpose of disinfection,
    but frequently for  accomplishing  other  biological  or
    chemical results.

Chlorination  break  point  - The application of chlorine to
    water,  sewage,  or  industrial  waste  containing  free
    ammonia  to  the  point  where free residual chlorine is
    available.
                            226

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Chlorination, Free Residual - The application of chlorine to
    water, sewage or industrial wastes to  produce  directly
    or  through  the  destruction  of ammonia, or of certain
    organic nitrogenous compounds a free available  chlorine
    residual.

Chlorine, Available - A term used in rating chlorinated lime
    and  hypochlorites  as  to  their total oxidizing power.
    Also a term formerly applied to residual  chlorine;  now
    obsolete.

Chlorine,  Combined Available Residual - That portion of the
    total residual chlorine remaining in  water,  sewage  or
    industrial  wastes  at  the  end  of  specified  contact
    period, which will react chemically and biologically  as
    chloramines or organic chloramines.

Chlorine  Demand  -  The  quantity  of  chlorine absorbed by
    wastewater  (or water)  in a given length of time.

Chlorine, Total  Residual  -  Free  residual  plus  combined
    residual.

Chlorite,  High-test  Hypo  -  A  combination  of  lime  and
    chlorine consisting largely of calcium hypochloride.

Chlorite, Sodium Hypo - A water solution of sodium hydroxide
    and  chlorine,  in  which  sodium  hypochlorite  is  the
    essential ingredient.

Cipolletti  Weir  - A contract weir of trapezoidal shape, in
    which the sides of the notch are given a  slope  of  one
    horizontal  to  four  vertical  to compensate as much as
    possible for the effect of end contractions.

Clarifier - A sedimentation tank.

Clear Well - A reservoir containing  water  which  has  been
    previously  filtered or purified before goining into the
    standpipes or distribution system.

Coils, digester - A system of pipes for hot water  or  steam
    installed  in a sludge digestion tank for the purpose of
    heating the sludge being treated.

Collection Systems  -  Piping  and/or  channel  systems  for
    gathering  storm,  domestic  or  industrial wastewaters.
    Can be combined or separate.

Collector, Grit - A device  placed  in  a  grit  chamber  to
    convey  deposited  grit  to  one  end of the chamber for
    removal.
                            227

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Collector, Sludge - A mechanical  device  for  scraping  the
    sludge  on the bottom of a settling tank to a sump pump,
    from which it can be drawn by hydrostatic or  mechanical
    action.

Colloids  -  A  finely  divided  dispersion  of one material
    called the "dispersed phase" (solid)  in another material
    which  is  called  the  "dispersion  medium"   (liquid).
    Normally negatively charged.

Color  -  A  measure  of  water quality,  made by eye or with
    proper instrumentation.

Color Bodies - Those complex molecules  which  impart  color
    (usually undesirable) to a solution.

Comminution  -  The  process of cutting and screening solids
    contained in wastewater flow before it enters  the  flow
    pumps or other units in the treatment plant.

Compatable  Pollutant  -  A  specific  substance  in a waste
    stream which alone  can  create  a  potential  pollution
    problem,  yet  is  used  to  the  advantage of a certain
    treatment  process  when  combined  with   other   waste
    streams.

Complexing  - The use of chelating or sequestering agents to
    form relatively loose chemical bonding  as  a  means  of
    treating  certain  pollutant such as  nickel, copper, and
    cobalt.

Composite Wastewater Sample - A  combination  of  individual
    samples   of  water  or  wastewater  taken  at  selected
    intervals, generally hourly for some  specified  period,
    to  minimize  the  effect  of  the  variability  of  the
    individual sample. Individual  samples  may  have  equal
    volume  or  may  be  roughly proportioned to the flow at
    time of sampling.

Concentration, Hydrogen Ion - The weight of hydrogen ions in
    grams per liter of solution.  Commonly expressed as  the
    pH   value   that   represents  the  logarithms  of  the
    receiprocal of the hydrogen ion concentration.

Conductance -  A  measure  of  the  conducting  power  of  a
    solution equal to the reciprical of the resistance.  The
    resistance is expressed in ohms.

Contact  Coagulation  -  A water clarification process which
    involves the addition of a  coagulant  with  appropriate
    mixing for the purpose of floe formation within a filter
    media, which will be periodically back-flushed to permit
                            228

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    the  separation  of  the  resulting solids from the main
    wastewater stream.

Contamination - A general term signifying  the  introduction
    into  water  of  microorganisms,  chemicals,  wastes  or
    sewage which renders the water unfit  for  its  intended
    use.

Contracted  Weir  -  A V-notch or other shaped cross-section
    weir for the purpose of flow measurement, as opposed  to
    a broad width weir for the purpose of level control.

Contraction  -  (1)  The extent to which the cross-sectional
    area of a jet,  nappe,  or  stream  is  decreased  after
    passing an orifice, weir, or notch. (2)  The reduction in
    cross-sectional area of a conduit along its longitudinal
    axis.

Control  Section  - The cross-section in a waterway which is
    the bottleneck for a given flow and which determines the
    energy head required to produce the flow.

Corporation Cock -A valve for joining a service  pipe  to  a
    street water main; it is generally owned and operated by
    the  water utility or department.  It cannot be operated
    from the surface.

Countercurrent Efficiency (Activated Carbon)   -  The  unique
    advantage  of  a  carbon column that permits spent anti-
    vated carbon  to  adsorb  impurities  before  the  semi-
    processed  stream  comes  in  contact with fresh carbon.
    This allows the maximum capacity of the activated carbon
    to be utilized.

Crest - The top of a dam, spillway, or weir,  to which  water
    must rise before passing over the structure.

Critical  Bed  Depth  (Activated Carbon) - In a carbon column
    the critical bed depth is the depth of  granular  carbon
    which  is  partially  spent.   It lies between the fresh
    carbon and the  spent  carbon  and  is  the  zone  where
    adsorption  takes place.  In a single-column system this
    is the amount of carbon that is not completely utilized.

Cross Connection - A water supply network and/or  wastewater
    collection  system  which as been designed so as to pre-
    vent "cross-connections" which  could  result  in  func-
    tional damage to the system.  The simpliest system is to
    have  two  separate  systems,  but  this  would  not  be
    justified   if   intersystems    usage    occurs    only
    occasionally, hence back-flow preventers and other means
    are often used.
                            229

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Cross-Sectional  Bed  Area  (Activated Carbon)  - The area of
    activated  carbon  through  which  the  stream  flow  is
    perpendicular.

Curb  Cock  -  A shutoff valve attached to the water service
    pipe from the water basin to the building installed near
    the curb, which may be operated by means of a dye key to
    start or stop flow  in  the  water  supply  lines  of  a
    building.

Current  Meter  -  A  device for determining the velocity of
    moving water.

Curve, Oxygen, Sag - A curve that represents the profile  of
    dissolved  oxygen  connect along the course of a stream,
    resulting from deoxygenation associated with biochemical
    oxidation of organic matter  and  reoxygenation  through
    the   absorption   of  atmospheric  oxygen  and  through
    biological photosynthesis.

Data - Records of observations and measurements of  physical
    facts,  occurrences, and conditions, reduced to written,
    graphical, or tabular form.

Data Correlation - The process of the conversion of  reduced
    data  into a functional relationship and the development
    of  the  significance  of  both   the   data   and   the
    relationships for the purpose of process evaluation.

Data Reduction - The process for the conversion of raw field
    data into a systematic flow which assists in recognizing
    errors, omissions and the overall data quality.

Data  Significance  - The result of the statistical analysis
    of a data group or bank  wherein  the  value  or  signi-
    ficance of the data receives a thorough appraisal.

Dechlorination  Process - A process by which excess chlorine
    is removed from water to a desired level, eg.  0.1  mg/1
    maximum   limit.   Usually  accomplishment  by  chemical
    reduction,  by  passage  through  carbons  beds  or   by
    aeration at a suitable pH.

Degreasing  -  The process of removing greasejs and oils from
    sewage, waste, and sludge.

Demand, Biochemical Oxygen (BOD)  - The  quantity  of  oxygen
    utilized  in the biochemical oxidation of organic matter
    in  a  specified  time  period  and   at   a   specified
    temperature.   It  is not related to the oxygen require-
    ments in chemical combustion being  determined  entirely
    by the availability of the material as a biological food
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    and  the  amount  of oxygen by the microorganisms during
    the oxidation.

Desorption - The opposite of adsorption.  A phenomenon where
    an  adsorbed  molecule  leaves  the   surface   of   the
    adsorbent.

Detention Time - The time allowed for solids to collect in a
    settling tank.  Theoretically detention time is equal to
    the  volume  of  the tank divided by the flow rate.  The
    actual detention time is determined by  the  purpose  of
    the  tank.   Also, the design resident time in a tank or
    reaction vessel which allows a chemical reaction  to  go
    to  completion,  such as the reduction of chromium +6 or
    the destruction of cyanide.

Dialysis - The separation of a colloid from a  substance  in
    true  solution  by  allowing  the  solution  to  diffuse
    through a semi-permeable membrane.

Diatomaceous Earth - A filter medium used for filtration  of
    effluents   from   secondary  and  tertiary  treatments,
    particularly when a very high grade of water  for  reuse
    in  certain industrial purposes is required also used as
    an  adsorbent  for  oils  and  oily  emulsions  in  some
    wastewater treatment designs.

Differential  Gauge  -  A pressure gauge used to measure the
    difference in pressure between two points in a  pipe  or
    receptacle containing a liquid.

Diffuser  -  A  porous  plate  or  tube through which air is
    forced and divided into minute bubbles for diffusion  in
    liquids.   Commonly  made  of  carborundum,  alundum and
    silica sand.

Diffusion, Ridge and Furrow Air - A method of  diffusing  in
    an  aeration tank of the activated sludge process, where
    porous tile diffusers are placed in depressions  treated
    by the sawtooth construction of the tank bottom, in rows
    across  the  tank  at  right  angles to the direction of
    flow.

Diffusion, Spiral Flow Air - A method of diffusing air in  a
    aeration  tank of the activated sludge process, where by
    means  of  properly  designed  baffles  and  the  proper
    location  of  diffusers,  a  spiral  helieal movement is
    given to both the air and the liquor in the tank.

Digestion - The biochemical decomposition of organic  matter
    which  results  in  the formation of mineral and simpler
    organic compounds.
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Disinfection - (1)  The killing of the  larger  portion  (but
    not   necessarily  all)   of  harmful  and  objectionable
    microorganisms in or on a medium by means of  chemicals,
    heat,  ultraviolet light, etc. (2)  The use of a chemical
    additive or other treatment  to  reduce  the  number  of
    bacteria particularly the pathogenic organisms.

Dissolved  Oxygen  (DO)   -  The  oxygen dissolved in sewage,
    water, or other liquid, usually expressed  in  miligrams
    per liter or percent of saturation.  It is the test used
    in BOD determination.

Dissolved  Solids  - Theoretically the anhydrous residues of
    the dissolved constituents in water.  Actually the  term
    is  defined  by  the  method  used in determination.  In
    water and  wastewater  treatment  the  Standard  Methods
    tests are used.

Diurnal Flow Curve - A curve which depicts flow distribution
    over the 24 hour day.

Drinking  Water  Standards  -  Standards  defined by law and
    applied to the quality of drinking water.

Educator  (Activated Carbon)  - A device with no moving  parts
    used  to  force an activated carbon water slurry through
    pipes to the desired location.

Effluent - (1) A liquid which  flows  out  of  a  containing
    space  (2)  sewage,   water or other liquid, partially or
    case may be, flowing out of a reservoir  basin,  or  the
    use  may  be  flowing  out  of  a  reservoir  basin,  or
    treatment plant or part thereof.

Electrical Conductivity - The reciprocal of  the  resistance
    in  ohms  measured  between opposite faces of centimeter
    cube of an aqueous solution at a specified  temperature.
    It is expressed as microohms per centimer at temperature
    degrees Celsius.

Elutriation  -  A  process  of  sludge conditioning in which
    certain constituents are moved  by  successive  flushing
    with  fresh water or plant effluent thereby reducing the
    need for using conditioning chemicals.

Emergency Procedures  -  These  various  special  procedures
    necessary  to  protect  the  environment from wastewater
    treatment plant failures due to power outages,  chemical
    spills,  equipment  failures,  major  storms and floods,
    etc.
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Emulsion Breaking - The method of preventing  the  carryover
    of  oils from one process to another by eliminating free
    oil by flotation,  and  emulsions  by  the  addition  of
    aluminum or ferrous sulfate.

End  Contraction  -   (1)  The extent of the reduction in the
    width of the nappe due to a constriction caused  by  the
    ends  of  the  weir notch.  (2) The walls of a weir notch
    which does not extend across the  entire  width  of  the
    channel of approach.

Energy  Head  - The height of the hydraulic grade line above
    the center line of a conduit plus the

Equalization Tank - A capacity used to  equalize  wastewater
    flows  or  pollutant  concentrations  in  effluents thus
    distributing it more evenly by hours or days.

Euetrophic Conditions - Lake water  quality  degradation  by
    enrichment  of  nutrients  resulting  in characteristics
    undersirable for means use of water.   Plant  growth  in
    forms  of  microscopic  algae  and  rooted aquatic weeds
    become prevelent in such situations.

Fats  (Wastes)  -  Triglyceride  esters  of   fatty   acids.
    Erroneously used as synonomous with grease.

Faculative  -  Having  the  power  to  live  under different
    conditions either with or without oxygen.

Feeder,  Chemical Dry - A mechanical device for applying  dry
    chemicals  to water sewage at a rate controlled manually
    or automatically by the rate of flow.

Feeder Chemical Solution - A mechanical device for  applying
    chemicals  in  liquid  to  water  and  sewage  at a rate
    controlled manually or  automatically  by  the  rate  of
    flow.

Filter,   High-Rate  -  A trickling filter operated at a high
    average daily dosing rate.  All between 10  and  30  mgd
    acre, sometimes including recirculation of effluent.

Filter,  Intermittent - A natural or artifical bed of sand or
    other  fine-grained  material  to  the  surface of which
    sewage is intermittently added  in  flooding  doses  and
    through  which  it  passes,   opportunity being given for
    filtration and the maintenance of aerotic conditions.

Filter,  Low-Rate - A trickling filter designed to receive  a
    small  load of BOD per unit volume of filtering material
    and to have a low dosage rate per unit of  surface  area
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     (usually  1  to  H mgd/acre).  Also called standard rate
    filter.

Filter, Rapid Sand - A filter for the purification of  water
    where  water  which has been previously treated,  usually
    by coagulation  and  sedimentation  is  passed  downward
    through a filtering medium consisting of a layer of sand
    or  prepared anthracite coal or other suitable material,
    usually from  2H  to  30  in  thick  and  resting  on  a
    supporting  bed  of  gravel  or  a porous medium such as
    carborundum. The filrate is  removed  by  an  underdrain
    system.  The filter is cleaned periodically by reversing
    the  flow  of  the  water  upward  through the filtering
    medium: sometimes  supplemented  by  mechanical  or  air
    agitition  during  backwashing  to  remove mud and other
    impurities that are lodged in the sand.

Filter, Roughing - A  sewage  filter  of  relatively  coarse
    material  operated  at  a  high  rate  as  a preliminary
    treatment.

Filter, Trickling - A filter consisting of an artifical  bed
    of  coarse  material,  such  as  broken stone, clinkers,
    slats, or brush over which  sewage  is  distributed  and
    applied   in  drops,  films,   or  spray,  from  troughs,
    drippers  moving  distributors  or  fixed  nozzles   and
    through  which  it  trickles  to  the  underdrain giving
    opportunity for the formation of zoogleal  slimes  which
    clarify and oxidize the sewage.

Filter,  Vacuum  - A filter consisting of a cylindrical drum
    mounted on a horizontal  axis,  covered  with  a  filter
    cloth  revolving  with apartial sumergence in liquid.  A
    vacuum is maintained under the cloth for the larger part
    of a revolution to extract  moisture  and  the  cake  is
    scraped off continously.

Filtration,  Biological  -  The  process of passing a liquid
    through a biological  filter  containing  media  on  the
    surfaces  of  which  zoogleal films develop which absorb
    and  adsorb  fine  suspended  colloridal  and  dissolved
    solids   and   which  release  various  biochemical  end
    products.

Float Gauge - A device for measuring the  elevation  of  the
    surface of a liquid, the actuating element of which is a
    buoyant  float  that  rests on the surface of the liquid
    and rises or  falls  with  it.   The  elevation  of  the
    surface  is  measured by a chain or tape attached to the
    float.
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Floe - A very fine, fluffy mass formed by the aggregation of
    fine suspended particles.

Flocculator - An apparatus designed  for  the  formation  of
    floe in water or sewage.

Flocculation  -  In  water  and  wastewater  treatment,  the
    agglomeration of colloidal and finely divided  suspended
    matter  after  coagulation  by gentle stirring by either
    mechanical or hydraulic means.  In biological wastewater
    treatment where coagulation is not  used,  agglomeration
    may be accomplished biologically.

Floatation  -  The rising of suspended matter to the surface
    of the liquid  in  a  tank  as  scum  by  aeration,  the
    evolution  of  gas,  chemicals,  electrolysis,  heat, or
    bacterial decomposition and the  subsequent  removal  of
    the scum by skimming.

Flowrate  -  Usually  expressed  as  liters/minute (gallons/
    minute)  or  liters/day  (million  gallons/day).   Design
    flowrate  is  that used to size the wastewater treatment
    process.  Peak flowrate is 1.5 to 2.5 times  design  and
    relates to the hydraulic flow limit and is specified for
    each  plant.   Flowrates  can  be  mixed  as  batch  and
    continuous where these two treatment modes are  used  on
    the same plant.

Flow-Nozzle Meter - A water meter of the differential medium
    type  in  which  the flow through the primary element or
    nozzle produces a pressure  difference  or  differential
    head,  which  the  secondary element, or float tube than
    uses as an indication of the rate of flow.

Flow-Proportioned Sample - A sampled stream whose pollutants
    are attributed to contributing streams in proportion  to
    the flow rates of the contributing streams.

Frequency  Distribution  - An arrangement or distribution of
    quantities pertaining to a single element  in  order  of
    their magnitude.

Gauging  Station  -  A location on a stream or conduit where
    measurements of discharge  are  customarily  made.   The
    location includes a stretch of channel through which the
    flow  is  uniform  and  a  control  downstream from this
    stretch.  The station usually has a recording  or  other
    gauge  for  measuring the elevation of the water surface
    in the channel or conduit.

Grab Sample - A single sample of wastewater taken at neither
    set time nor flow.
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Grease - In wastewater,  a  group  of  substances  including
    fats,  waxes,  free  fatty  acids,  calcium and magnesium
    soaps,  mineral  oils,  and   certain   other   nonfatty
    materials.   The  type  of  solvent  and method used for
    extraction should be stated for quantification.

Grease Skimmer - A device for removing  floating  grease  or
    scum from the surface of wastewater in a tank.

Grit  -  The  heavy  matter in water or sewage such as sand,
    gravel and cinders.

Grit Chamber - A detention chamber or an  enlargement  of  a
    sewer  designed  to  reduce  the velocity of flow of the
    liquid to permit the separation of mineral from  organic
    solids by differential sedimentation.

Hardness  -  A characteristic of water, imparted by salts of
    calcium,  magnesium,  and  iron  such  as  bicarbonates,
    carbonates, sulfates, chlorides, and nitrates that cause
    curdling of soap, deposition of scale in boilers, damage
    in  some industrial process, and sometimes objectionable
    taste.  It may be determined by  a  standard  laboratory
    procedure  or  computed  from the amounts of calcium and
    magnesium as well as iron, aluminum, manganese,   barium,
    strontium,  and  zinc,  and  is  expressed as equivalent
    calcium carbonate.

Heat of Adsorption - The heat given off when  molecules  are
    adsorbed.

Heavy  Metals - A general name given to the ions of metallic
    elements such as copper, zinc, chromium,  and  aluminum.
    They  are  normally removed from a wastewater forming an
    insoluble precipitate (usually a metallic hydroxide).

Hook Gauge - A pointed, U-shaped hoot attached to  a  gradu-
    ated  staff  or  vernier  scale,  used  in  the accurate
    measurement of the elevation of a  water  surface.   The
    hook  is submerged, and then raised, usually by means of
    a screw, until the point just  makes  a  pimple  on  the
    water surface.

Hydraulic  Surge  -  A pressure increase in a pipeline which
    accompanies a sudden decrease in the flow velocity.   In
    some  cases this increased pressure may cause rupture of
    the pipe.

Industrial Wastes - The liquid wastes from  industrial  pro-
    cesses as distinct from domestic or sanitary wastes.
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Incineration - The combustion (by burning)  of organic matter
    in wastewater sludge solids after water evaporation from
    the solids.

Index, Sludge - The volume of mililiters occupied by aerated
    mixed  liquor  containing  1  gram  of  dry solids after
    settling 80 min. commonly referred  to  as  the  Mohlman
    index.   The Donaldson index which is also commonly used
    is obtained by dividing 100 by the Mohlman index.

Influent - Sewage, water or  other  liquid,  either  raw  or
    partly  treated,  flowing  into  a  reservoir  basin, or
    treatment plant or any part thereof.

Invert - The floor, bottom or lowest portion of the internal
    cross section of a closed conduit.

Iodine Number (Activated Carbon) - The iodine number is  the
    miligrams  of  iodine  adsorbed  1  gram  of carbon at a
    filtrate concentration of 0.02N iodine.

lonization - The process of the formation  of  ions  by  the
    splitting of molecules of electrolytes in solution.

Irrigation  Spray  -  Irrigation by means of nozzles along a
    pipe on the ground or from perforated overhead pipes.

Lagoon - (1)  A shallow body of water  as  a  pond  or  lake,
    which  usually  has a shallow, restricted inlet from the
    sea. (2)  A pond  containing  raw  or  partially  treated
    wastewater  in  which aerobic or anaerobic stabilization
    occurs.

Lime - Any of a family of chemicals  consisting  essentially
    of calcium hydroxide made from limestone (calcite)  which
    is  composed  almost  wholly  of  calcium carbonate or a
    mixture of calcium and magnesium carbonates.

Liquor, Mixed - A mixture of activated sludge and sewage  in
    the   aeration   tank   undergoining   activated  sludge
    treatment.

Liquor, Supernatant - (1)   The  liquor  overlying  deposited
    solids.   (2)  the liquid in a sludge digestion tank which
    lies between the sludge at the bottom and  the  floating
    scum at the top.

Loss  of  Head  Gage  -  A gage on a rapid sand filter which
    indicates the loss of head  involved  in  the  filtering
    operation  whereby the operator is able to ascertain the
    need for filter backwashing.
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Macropore - The pores in activated carbon which  are  larger
     (diameter) than l.OOOA.

Makeup  Carbon  - Fresh granular activated carbon which must
    be added to a column system after a  regeneration  cycle
    or  when  deemed  necessary to bring the total amount of
    carbon to specification.

Manometer  -  An  instrument  for  measuring  pressure.   It
    usually  consists of a U-shaped tube containing a liquid
    the surface of which  is  one  end  of  the  tube  moves
    proportionally with changes in pressure on the liquid in
    the  other  end.   Also,  a  tube  type  of differential
    pressure gauge.

Mean Velocity - The average velocity of a stream flowing  in
    a  channel  or  conduit at a given cross section or in a
    given reach.  It is equal to the  discharge  divided  by
    the  cross  sectional  area  of  the  reach. Also called
    average velocity.

Mesh Size (Activated Carbon).- The particle size of granular
    activated carbon as determined by the U.S. Sieve series.
    Particle size distribution within a mesh series is given
    in the specification of the particular carbon.

Methylene Blue Number (Activated  Carbon)  -  The  methylene
    blue number is the milligrams of methylene blue adsorbed
    by  1  gram  of carbon in equilibrium with a solution of
    methylene blue having a concentration of 1.0 img/1.

Methylpranqe Alkalinity - A measure of the total  alkalinity
    of an aqueous suspension or solution.  It is measured by
    the  quantity  of  sulfuric  acid  required to bring the
    water pH to a value of 1.3 as indicated by the change in
    color of methyl orange.  It is  expressed  in  miligrams
    CACO3_ per liter.

Micropore  -  The  pores  in activated carbon which range in
    size (diameter) from 10 to lrOOO A.

Mjligrams Per Liter (mq/1)  - This is  a  weight  per  volume
    designation used in water and wastewater analysis.

Mixed  Media  Filtration  -  A  filter  which uses 2 or more
    filter  materials  of   differing   specific   gravities
    selected so as to produce a filter uniformly graded from
    coarse 1..  fine.

Monitoring  - (1) The procedure or operation of locating and
    measuring radioactive contamination by means  of  survey
    instruments  that  can detect and measure, as dose rate.
                            238

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    ionizing  radiations  (2)   the  measurements   sometimes
    continous, of water quality.

Most  Probable  Number  (MPN)  - That number of organisms per
    unit volume that, in accordance with statistical theory,
    would be more likely than any other number to yield  the
    obserbed   test  result  with  the  greatest  frequency.
    Expressed as desnity of organisms per 100  ml.   Results
    are  computed  from  the  number of positive findings of
    coliform-group organisms resulting from multiple-portion
    decimal-dilution plantings.

Nappe - The sheet or curtain of water overflowing a weir  or
    dam.   When  freely  overflowing any given structure, it
    has a well-defined upper and lower surface.

Neutralization  -  Reaction  of  acid  or  alkali  with  the
    opposite  reagent  until  the concentrations of hydrogen
    and hydroxyl ions in solution are approximately equal.

Nitrification - The conversion of  nitrogenous  matter  into
    nitrates by bacteria.

Nonjonic  Surfactant  -  A  general family of surfactants so
    called because in solution the entire  molecule  remains
    associated.   Nonionic  molecules  orient  themselves at
    surfaces  not  by  an  electrical  charge,  but  through
    separate  grease-solubilizing  and  water-soluble groups
    within the molecule.

Nonsettleable Matter - The suspended matter which  does  not
    settle  nor float to the surface of water in a period of
    one hour.

Nonsettleable Solids - Wastewater matter that will  stay  in
    suspension  for an extended period of time.  Such period
    may be arbitrarily taken for  testing  purposes  as  one
    hour.

Notch - An opening in a dam, spillway, or measuring weir for
    the passage of water.

Nozzle - (1)  A short, cone-shaped tube used as an outlet for
    a  hose  or pipe.  The velocity of the merging stream of
    water is increased by the reduction in  cross  sectional
    area  of  the  nozzle   (2)   a short piece of pipe with a
    flange on one end and a saddle flange on the other end.

Nutrients - Materials which are considered to  be  essential
    to support biological life.
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Odor  Control  -  The  elimination  of odor-causing valatile
    substances  associated  with  organic   matter,   living
    organisms,   and   cases.    The  most  common,  control
    measurement in use  are  the  application  of  activated
    carbon  residual  chlorination,  chlorine dioxide, ozone
    and aeration.

Odor Threshold - The point at which after  successive  dilu-
    tions  with  odorless  water, the odor of a water sample
    can just be detected.  The threshold odor  is  expressed
    quantitatively  by  the  number  of  times the sample is
    diluted with odorless water.

Oil and Grease - Those materials which are exgractable  from
    wastewater  with  hexane, chloroform if other content of
    these specific solvents pollutants in  water  or  waste-
    water (in mg/1 of ppm)  which can significantly influence
    the environment.

Open-Channel Flow - Flow of a fluid with its surface exposed
    to  the  atmosphere.  The conduit may be an open channel
    or a closed conduit flowing partly full.

Operation Qualifications, Treatment Plant - Usually  defined
    by a licence issued by local authorities.

Organic  Matter - Chemical substances of animal or vegetable
    origin, or more correctly of basically carbon structure,
    comprising  compounds  consisting  of  hydrocarbons  and
    their deviations.

Organic  Nitrogen  -  Nitrogen combined in organic molecules
    such as protein, amines, and amino acids.

Orifice - (1) An opening with closed perimeter,  usually  of
    regular  form,  in  a plate, wall, or partition, through
    which water may flow generally used for the  purpose  of
    measurement  of  control of such water.  The edge may be
    sharp or of another configuration (2)  the end of a small
    tube such as a Pitot tube.

Orifice Plate - A plate containing an  orifice.   In  pipes,
    the plate is usually inserted between a pair of flanges,
    and  the  orifice  is  smaller  in  area  than the cross
    section of the pipe.

Orthophosphate - An acid or salt  containing  phosphorus  as
    PO4..

Outfall  -  The  point  or location where sewage or drainage
    discharges from a sewer, drain, or conduit.
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Overflow Storm -  A  weir,  orifice,  or  other  device  for
    permitting  the  discharge from a combined sewer of that
    part of the flow in escess of that which  the  sewer  is
    designed to carry.

Oxidation  -  The  addition  of  oxygen to a compound.   More
    generally, any  reaction  which  involves  the  loss  of
    electrons from an atom.

Oxidation  Pond  -  A basin used for retention of wastewater
    before final disposal, in which biological oxidation  of
    organic  material  is effected by natural or artifically
    accelerated transfer of oxygen to the water from air.

Oxidation Reduction Potential (ORP) - The potential required
    to transfer electrons from the oxidant to the  reductant
    and  used  as  a  qualitative  measure  of  the state of
    oxidation in wastewater treatment systems.

Oxygen Consumed - The  quantity  of  oxygen  taken  up  from
    potassium   permananganate   in  solution  by  a  liquid
    containing organic  matter.    Commonly  regarded  as  an
    index  of  the  carbonaceous  matter  present.  Time and
    temperature must be specified.

Oxygen Dissolved - Usually designated  as  DO.   The  oxygen
    dissolved  in  sewage  water,  or  othe  rliquid usually
    expressed in parts per million or  percent  of  statura-
    tion.

Ozone  - Oxygen in molecular form with three atoms of oxygen
    forming  each  molecule.   Atmospheric  oxygen   is   in
    molecular  form  but each molecule contains two atoms of
    oxygen.   Ozone  is  formed  by  passing  high   voltage
    electric  charges  through  dry  air.  The third atom of
    oxygen in each molecule of ozones is loosely bound to it
    and is easily released.

Parshall Flume - A calibrated device developed  by  Parshall
    for measuring the flow of liquid in an open conduit.  It
    consists  essentially of a contracting length, a throat,
    and an expanding length.  At the throat is a  sill  over
    which  the flow passes as critical depth.  The upper and
    lower heads are each measured  at  a  definite  distance
    from  the  sill.   The lower head not be measured unless
    the sill is submerged more than about 67 percent.

Pathogenic Bacteria - Bacteria which may  cause  disease  in
    the organisms by their parasitic growth.

pH  -  The  reciprocal  of the logarithm of the hydrogen ion
    concentration.  The  concentration  is  the  weight   of
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    hydrogen  ions,  in grams per liter of solution. Neutral
    water, for example, has a pH value of 7 and hydrogen ion
    concentration of 10.7.

pH Adjustment -  A  means  of  maintaining  the  optimum  pH
    through  the use of chemical additives. Can be manual or
    automatic,  or  automatic  with  flow   corrections   pH
    adjustment is not a linear function.

Phenolein  Alkalinity   -  A measure  of the hydroxides plus
    one half of the normal carbonates in aqueous suspension.
    Measured by the amount  of  sulfuric  acid  required  to
    bring  the water to a pH value of 8.3, as indicated by a
    change in color of phenolphthaiein.  It is expressed  in
    parts per million of calcium carbonate.

Pitot  Tube - A device for measuring the velocity of flowing
    fluid by using the velocity head of  the  stream  as  an
    index  velocity.   It consists essentially of an orifice
    held to point upstream and  connected  with  a  tube  in
    which  the  impact  pressure due to velocity head may be
    observed and measured.  It also may be constructed  with
    an  upstream  and downstream orifice, or with an orifice
    pointing  upstream  to  measure  the  velocity  head  or
    pressure  and  piezometer  holes  in  a  coaxial tube to
    measure the static head or pressure,  in which  case  the
    difference in pressure is the index of velocity.

Pollution  Load  - A measure of the strength of a wastewater
    in terms of its solids or oxygen-demanding  characteris-
    tics, or in terms of harm to receiving waters.

Pollution  Water  - The introduction into a body of water of
    substances of such character and of such  quantity  that
    its  natural  quality  is  so  altered  as to impair its
    usefulness or render  it  offensive  to  the  senses  of
    sight, taste, or smell.

Polyelectrolytes - Used as a coagulant or a coagulant aid in
    water  and  wastewater  treatment  (activated  carbon is
    another coagulant aid).   They  are  synthetic  polymers
    having  a  high  molecular  weight.  Anionic  negatively
    charged.  Nonionic  carry  both  negative  and  positive
    charges  (Cationic postively charged most popular).

Pond,  Sewage Oxidation - A pond either natural or artifical
    into which partly treated sewage of  discharged  and  in
    which  natural  purification  processes take place under
    the influence of sunlight and air.

Poolingf Filter - The formation of pools of  sewage  on  the
    surface of filters, caused by surface cloggings.
                            2H2

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Pore  Volume  (activated  carbon)  -  The pore volume is the
    difference in the volumetric  displacement  by  granular
    activated  carbon  in  mercury and in helium at standard
    conditions.

Preaeration - A preparatory treatment of  sewage  consisting
    of  aeration  to  remove  gases,  add oxygen, or promote
    flotation of grease and aid coagulation.

Prechlorination - (1) Chlorination of water prior to filtra-
    tion. (2) Chlorination of sewage prior to treatment.

Precipitation,  chemical  -  (1)  Precipitation  induced  by
    addition of chemicals (2)  The process of softening water
    by   the   addition   of   lime  and  soda  ash  as  the
    precipitants.

Pretreatment - Any  wastewater  treatment  process  used  to
    reduce pollution load partially before the wastewater is
    introduced  into  a  main sewer system or delivered to a
    treatment  plant  for  substantial  reduction   of   the
    pollution load.

Primary  Treatment  -  A process to remove substantially all
    floating  and  setteable  solids   in   wastewater   and
    partially  to  reduce  the  concentration  of  suspended
    solids.

Probability Curve -  A curve that  expresses  the  cumulative
    frequency  of  occurrence  of a given event, based on an
    extended record  of  past  occurrences.   The  curve  is
    usually  plotted on specially prepared coordinate paper,
    with ordinates representing magnitude equal to, or  less
    than,   the   event,   and  abscissas  representing  the
    probability, time, or other units of incidence.

Process Activated Sludge -  A  biological  sewage  treatment
    process  in  which  a  mixture  of  sewage and activated
    sludge is agitated and aerated.  The activated sludge is
    subsequently separted from  the  treated  sewage  (mixed
    liquor)   by sedimentation,  and wasted or returned to the
    process as needed.  The  treated  sewage  overflows  the
    weir  of  the settling tank in which separation from the
    sludge takes place.

Process,  Biological  -  The  process  by  which  the   life
    activities  of bacteria, and other microorganisms in the
    seach for food break down complex organic materials into
    simple,  more stable  substances.   Self-purification  of
    sewage  polluted  streams,  sludge digestion, and all so-
    called secondary  sewage  treatments  result  from  this
    process.  Also called biochemical process.
                            243

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Process,  Oxidation - Any method of sewage treatment for the
    oxidation of the putrescible organic  matter  the  usual
    methods  are  biological  filtration,  and the activated
    sludge process.

Purification Degree - (1) A measure of  the  completness  of
    destruction  or  removal  of  objectionable  impurities.
    such as bacteria and  hardness  from  water  by  natural
    means  (self-puriciation)   or by treatment (2)  A measure
    of the removal,  oxidation,  or  destruction  of  solids
    organic  matter,  bacteria, or other specified substance
    effected by sewage treatment processes.

Putrefaction - Biological decomposition  of  organic  matter
    accompanied  by  the  production  of  foul-smelling  as-
    sociated with anaerobic conditions.

Rate Oxidation - The rate at which  the  organic  matter  in
    sewage is stablized.

Ratio  Dosing - The maximum rate of application of sewage to
    a filter on any unit of area,  divided  by  the  average
    rate of application on that area.

Reactivation  (activated carbon) - The removal of adsorbates
    from spent granular activated carbon  which  will  allow
    the  carbon  to  be  reused.  This is also called regen-
    eration and revivfication.

Reaeration Sludge - The continous aeration of  sludge  after
    its intial aeration in the activated sludge process.

Recirculation  - The refiltration of all or a portion of the
    effluent in a high rate trickling filter for the purpose
    of incoming flow to reduce its strength.

Reduction overall - The percentage reduction  in  the  final
    effluent as compared with the raw sewage.

Reoxygenation - The replenishment of oxygen in a stream from
    (1)  dilution  water  entering the stream (2) biological
    oxygenation through the  activities  of  certain  oxygen
    producting plants and  (3)  atmospheric reaeration.

Reservoir - A pond, lake, tank, basin, or other space either
    natural  in  origin  or  created  in whole or in part by
    building of engineering  structures.   It  is  used  for
    storage, regulation, and control of water.

Recorder  -  A  device that makes a graph or other automatic
    record of the stage, pressure, depth, velocity,  or  the
                            244

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    movement  or  position  of  water  controlling  devices,
    usually as a function of time.

Recovery  Products  -  Substances  regarded  as   wastewater
    pollutants which are recovered for their potential value
    through  sale  or reuse; recovery often is used to lower
    or partially offset treatment (or recovery)  costs.

Rectangular Weir - A weir having a notch that is rectangular
    in shape.

Reduction Practices - (1)  Wastewater reduction practices can
    mean the reduction of water usage to lower the volume of
    wastewater  requiring  treatment  and  (2)  the  use  of
    chemical  reductant materials to lower the valance state
    of a specific wastewater pollutant.

Reduction Treatment - The opposite  of  oxidation  treatment
    where  in  a  reductant  (chemical) is used to lower the
    valence state of a pollutant to a less toxic  form  e.g.
    the use of SO2 to "reduce" chromium +6 to chromium +3 in
    an acidic solution.

Refractory   Orqanics   -   Organic   pollutants  which  are
    chemically oxidation,  e.g. DDT pesticide.

Residual Chlorine - Chlorine remaining in  water  or  waste-
    water at the end of specified contact period as combined
    or free chlorine.

Salinity  -  (1)  The relative concentration of salts, usually
    sodium chloride,  in  a  given  water.   It  is  usually
    expressed in terms of the number of parts per million of
    chloride  (Cl).  (2)   A  measure of the concentration of
    dissolved mineral substances in water.

Sampler - A device used with or without flow measurement  to
    obtain   an  aliquot  portion  of  water  or  waste  for
    analytical purposes.  May be designed for taking a single
    sample   (grab) ,  composite  sample,  continous   sample,
    periodic sample.

Sanitary  Sewer  -  A  sewer  that carries liquid and water-
    carried wastes from  residences,  commercial  buildings,
    industrial  plants,  and institutions together with minor
    quantities of ground-storm, and surface waters that  are
    not admitted intentionally.

Screen  -  (1)   A device  with openings, generally of uniform
    size, used to retain  or  remove  suspended  or  floating
    solids  in  flowing  water  or wastewater and to prevent
    them from entering an intake or passing a given point in
                            245

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    a  conduit.   The  screening  element  may  consist   of
    parallel  bars,  rods,  wires,  grating,   wire  mesh, or
    perforated plate, and the openings may be of any  shape,
    although  they are usually circular or rectangular.  (2)
    A device used to segregate  granular  material  such  as
    sand, crushed rock, and soil into various sizes.

Secondary Settling Tank - A tank through which effluent from
    some  prior  treatment  process flows for the purpose of
    removing settleable solids.

Secondary Wastewater Treatment - The treatment of wastewater
    by biological methods after primary treatment  by  sedi-
    mentation.

Second  Stage  Biological  Oxygen  Demand - That part of the
    oxygen demand associated with the biochemical  oxidation
    of  nitrogenous  material.  As  the  term  implies,  the
    oxidation of the nitrogenous materials usually does  not
    start  until  a portion of the carbonaceous material has
    been oxidized during the first stage.

Sed JMesTtation - The process of subsidence and deposition  of
    suspended  matter carried by water, wastewater, or other
    liquids, by  gravity.   It  is  usally  accomplished  by
    reducing  the  velocity of the liquid below the point at
    which it can transport  the  suspended  material.   Also
    called settling.

Seeding Sludge - The inoculation of undigested sewage solids
    with  sludge  that  has  undergone decomposition for the
    purpose  of  introducing  favorable  organisms,  thereby
    accelerating the intial stages of digestion.

Sewage  Combined  - A sewage containing both sanitary sewage
    and surface or storm water with  or  without  industrial
    wastes.

Sewage  Dilute  -  Sewage  containing  less  than 150 ppm of
    suspended solids and BOD  (weak sewage)„

Sewage Industrial - Sewage in which industrial  wastes  pre-
    dominate .

Sewage Raw - Sewage prior to receiving any treatment.

Sewage  Settled  -  Sewage from which most of the settleable
    solids have been removed by sedimentation.

Sewage Storm - Liquid flowing in sewers during or  following
    a period of heavy rainfall and resulting therefrom.
                            246

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Sewer  -  A  pipe or conduit, generally closed, but normally
    not flowing full for carrying  sewage  and  other  waste
    liquids.

Sewer Intercepting - A sewer which receives dry-weather flow
    from  a  number  of  transverse  sewers  or outlets, and
    fequently additional, predetermined quantities of  storm
    water   (if  from  a  combined system) and which conducts
    such waters to a point for treatment or disposal-

Semipermeable Membrane - A barrier, usually thin, that  per-
    mits  passage  of  particles  up to a certain size or of
    special nature.  Often used to  separate  colloids  from
    their suspending liquid, as in dialysis.

Settleable Solids - (1)  That matter in wastewater which will
    not  stay  in  suspension  during a preselected settling
    period, such as one hour,  but  either  settles  to  the
    bottom  or  floats  to  the  top.  (2) In the Imhoff cone
    test, the volume of matter that settles to the bottom of
    the cone in one hour,

Skimming Tank - A tank so designed that floating matter will
    rise and remain on the surface of the  wastewater  until
    removed,  while  the liquid discharges continously under
    certain walls or scum boards.

Sludge - The solids  (and  accompanying  water  and  organic
    matter)  which  are  separated from sewage or industrial
    wastewater  in  treatment  plant   facilities.    Sludge
    separation  and disposal is one of the major expenses in
    wastewater treatment.

Sludge Conditioning - A process employed to  prepare  sludge
    for  final  disposal  can be thickening, digesting,, heat
    treatment etc.

Sludge Digestion - The process by which organic or  volatile
    matter  in  sludge is gasified, liquidfied, mineralized,
    or converted into more stable organic matter through the
    activities of either anaerobic or aerobic organisms.

Sludge Disposal - The final disposal of solid wastes includ-
    ing the use of sewage sludges as  fertilizers  and  soil
    builders;  dumping  sludge  at sea; and filling lowlying
    lands.

Sludge thickening - The increase in solids concentration  of
    sludge in a sedimentation of digestion tank.

Spills  -  A  chemical or material spill is an unintentional
    discharge of more than 10 percent of  the  sewage  daily
                            247

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    usage  of  a regularly used substance.   In the case of a
    rarely  used  (one  per  year  or  less)    chemical   or
    substance,  a  spill is that amount that would result in
    10% added loading to the  normal  air,   water  or  solid
    waste   loadings  measured  as  the  closest  equivalent
    pollutant.

Stabilization Lagoon - A shallow pond for storage of  waste-
    water  before discharge.  Such lagoons  may serve only to
    detain  and  equalize  wastewater   composition   before
    regulated discharge to a stream, but often they are used
    for biological oxidation.

Stabilization  Pond  -  A  type  of  oxidation pond in which
    biological oxidation of organic matter   is  effected  by
    natural or artifically accelerated transfer of oxygen to
    the water from air.

Staff  Gauge  - A graduated scale, vertical unless otherwise
    specified, on a plank, metal  plate,  pier,  wall  etc.,
    used  to  indicate the height of a fluid surface above a
    specified point or datum plane,

Stage Discharge Relation - The relation between gauge height
    and discharge of  a  stream  or  conduit  at  a  gaugint
    station.   This relation is shown by the rating curve or
    rating table for such stations.

Static Head - (1)  The  total  head  without  reduction  for
    velocity  head or losses; for example,  the difference in
    the elevation of headwater and tail  water  of  a  power
    plant.  (2)  The vertical distance between the free level
    of  the source of supply and the point  of free discharge
    or the level of the free surface.

Steady Flow - (1) A flow in which the rate   or  quantity  of
    water  passing  a  given  point per unit of time remains
    consrant.  (2) Flow in which the  velocity  vector  does
    not change in either magnitude or direction with respect
    to time at any point or section.

Steady  Uniform  Flow - A flow in which the velocity and the
    quantity of water flowing per unit remains constant.

Stilling Well - A pipe, chamber, or  compartment  with  com-
    partively  small  inlet  or  inlets communicating with a
    main body of water.  Its purpose is to dampen  waves  or
    surges, while permitting the water level within the well
    to  rise and fall with the major fluctations of the main
    body of water.  It is used with  waterrneasuring  devices
    to improve accuracy of measurement.
                            248

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Submerged  Weir  -  A  weir  that when in use, has the water
    level on the downstream side at an elevation equal to or
    higher than, the weir crest. The rate  of  discharge  is
    affected by the tail water.  Also called drowned weir.

Suppressed  Weir  - A weir with one or both sides flush with
    the channel of approach.  This prevents  contraction  of
    the  nappe  adjacent to the flush side.  The suppression
    may occur on one end or both ends.

Surveys - The gathering of numerical and other forms of data
    from the field, or plant site for the subsequent purpose
    of data reduction, correlation and analysis  leading  to
    improve  water  supply,  treatment,  use  and wastewater
    treatment, described in  total  as  a  Water  Management
    Program.

Suspended  Matter  -   (1)  Solids  in  suspension  in water,
    wastewater or effluent.   (2) Solids in  suspension  that
    can  be removed readily by standard filtering procedures
    in a laboratory.   Suspended  Solids-  (1)  Solids  that
    either  float on the surface of, or are in suspension in
    water, wastewater,  or  other  liquids,  and  which  are
    largely  removable  by  laboratory  filtering.  (2)   The
    quantity  of  material  removed  from  wastewater  in  a
    laboratory  test, as prescribed in "Standard Methods for
    the Examination of Water and Wastewater" and referred to
    as nonfilterable residue.

Tertiary Treatment - A process  to  remove  practically  all
    solids  and  organic  matter  from  wastewater. Granular
    activated carbon  filtration  is  a  tertiary  treatment
    process.   Phosphate  removal by chemical coagulation is
    also regarded as a step in tertiary treatment.

Threshold Odor - The minimum odor of the water  sample  that
    can  just  be  detected  after successive dilutions with
    odorless water.  Also called odor threshold.

Titration - The determination of a constituent  in  a  known
    volume  of  solution by the measured addition of a solu-
    tion of known strength to completion of the reaction  as
    signaled by observation of an end point.

Total  Organic Carbon (TOC)  - TOC is a measure of the amount
    of carbon in a sample originating  from  organic  matter
    only.  The  test  is  run  by  burning  the  sample  and
    measuring the CO produced.

Tracer - (1) A foreign substance mixed with or attached to a
    given substance for the determination of the location or
    distribution  of  the  substance.  (2)   An  element   or
                            249

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    compound  that  has been made radioactive so that it can
    be easily followed (traced)  in biological and industrial
    processes.   Radiation  emitted  by   the   radioisotope
    pinpoints its location.

Treatment  Efficiency  -   Usually  refers  to the percentage
    reduction of a specific or  group  of  pollutants  by  a
    specific wastewater treatment step or treatment plant.

Turbidmeter - An instrument for measurement of turbidity, in
    which   a   standard  suspension  usually  is  used  for
    reference.

Turbidity - (1)  A condition in water or wastewater caused by
    the presence  of  suspended  matter,  resulting  in  the
    scattering  and  absorption of light rays. (2) A measure
    of fine suspended matter in liquids. (3)   An  analytical
    quantity  usually  reported in arbitrary turbidity units
    determined by measurements of light diffraction.

Turbulent Flow - (1)  The flow of a  liquid  past  an  object
    such  that  the velocity at any fixed point in the fluid
    varies irregularly. (2) A type of liquid flow  in  which
    there  is  an  unsteady  motion of the particles and the
    motion at a fixed point varies in  no  definite  manner.
    Sometimes called eddy flow,  sinuous flow.

Ultimate Biochemical Oxygen Demand - (1) Commonly, the total
    quantity  of  oxygen  required to satisfy completely the
    first-stage  biochemical   oxygen   demand.   (2)    More
    strickly,  the  quantity  of oxygen required to statisfy
    completly both  the  first-stage  and  the  second-stage
    biochemical oxygen demands.

Velocity  Area  Method -  A method used to determine the dis-
    charge of a stream or any open channel by measuring  the
    velocity  of  the flowing water at several points within
    the cross section of  the  stream  and  summing  up  the
    products   of  these  velocities  and  their  respective
    fraction of the total area.

Velocity Meter - A water meter that operates  on  the  prin-
    ciple  that the vanes of the wheel move at approximately
    the same velocity as the flowing water.

Velocity of Approach - The mean velocity in  a  conduit  im-
    mediately  upstream  from  a weir, dam, venturi tube, or
    other structure.

Vena Contracta - The most  contacted  sectional  area  of  a
    stream  jet, or nappe issuing through or over an orifice
                            250

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    or weir notch. It occurs downstream from  the  plane  of
    such notch or orifice.

Venturi  Flume  - A open flume with a contracted throat that
    causes a drop in the hydraulic grade line.  It  is  used
    for measuring flow.

Venturi  Meter  - A differential meter for measuring flow of
    water or other fluid through closed conduits  of  pipes,
    consisting  of  a  venturi  tube and one of several pro-
    prietary forms of  flow-registering  devices.  The  dif-
    ference  in  velocity heads between the entrance and the
    contracted throat is an indication of the rate of flow.

Venturi Tube - A closed conduit or pipe, used to measure the
    rate of fluids, containing a gradual  contraction  to  a
    throat,  which causes a pressure-head reduction by which
    the velocity  may  be  determined.  The  contraction  is
    usually, but not necessarily, followed by an enlargement
    to the original size.

Volatile  Solids  -  The quantity of solids in water, waste-
    water or other liquids, lost  on  ignition  of  the  dry
    solids at 600°C.

Wastewater  Survey  -  An  investigation  of the quality and
    characteristics  of  each  waste  stream,   as   in   an
    industrial plant or municipality.

Water  Level  Recorder - A device for producing, graphically
    or otherwise, a record of the rise and fall of  a  water
    surface with respect to time.

Water  Meter  -  A device installed in a pipe under pressure
    for measuring and  registering  the  quantity  of  water
    passing through it.

Water Renovation - Wastewater treatment of sufficient degree
    to  allow the reuse of water for one or more purposes in
    a given water supply/treatment system.

Weir - (1)  A diversion dam. (2)  A device that  has  a  crest
    and some side containment of known geometric shape, such
    as  a  V, trapezoid, or rectangle and is used to measure
    flow of liquid. The liquid surface  is  exposed  to  the
    atmosphere.  Flow is related to upstream height of water
    above the crest, to position of crest  with  respect  to
    downstream  water  surface,   and to geometry of the weir
    opening.
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                                   APPENDIX
                                   METRIC  UNITS
                                  CONVERSION  TABLE
MULTIPLY  (ENGLISH UNITS)

    EKGLISH UNIT      ABBREVIATION
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
galIon/minute
horsepower
inches
inches of mercury
pounds
million gallons/day
mile
pound/square
  inch (gauge)
square feet
square inches
tons (ehort)
yard
* Actual conversion, not a multiplier
      OU.S.GOVERNMENTPRINTINGOFFICE  1977- 234-846:6285
     by                TO OBTAIN  (METRIC  UNITS)

CONVERSION   ABBREVIATION   METRIC  UNIT
                            hectares
                            cubic meters

                            kilogram -  calories

                            kilogram calories/kilogram
                            cubic meters/minute
                            cubic meters/minute
                            cubic meters
                            liters
                            cubic centimeters
                            degree Centigrade
                            meters
                            liters
                            liters/second
                            killowatts
                            centimeters
                            atmospheres
                            kilograms
                            cubic meters/day
                            kilometer

                            atmospheres  (absolute)
                            square meters
                            square centimeters
                            metric tons  (1000 kilograms)
                            meters
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
sq ft
sq in
t
y
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
0.063]
0.7457
2.54
0.03342
0.454
3,785
1.609
(0.06805 psig +1)*
0.0929
6.452
0.907
0.9144
ha
cu ra
kg cal
kg ca] /kg
cu m/niin
cu m/rflin
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km
atm
sq m
eq cm
kkg
m
                                    253

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