United States
            Environmental Protection
            Agency
             Industrial Environmental Research
             Laboratory
             Cincinnati OH 45268
EPA-600/2-81-028
February 1981
            Research and Development
&EPA
Third
Conference  on
Advanced  Pollution
Control for the Metal
Finishing Industry

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                                     EPA-600/2-81-028
                                     February 1981
          Third Conference
 On Advanced Pollution Control
For the Metal Finishing Industry
               PRESENTED AT:
    ORLANDO HYATT HOUSE, KISSIMMEE, FL
              APRIL 14 - 16, 1980
               Co-sponsored by:
       • The American Electroplaters' Society
   The United States Environmental Protection Agency

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              ChlCc-iP
        Industrial Environmental Research Laboratory
          Office of Research and Development
          U.S. Environmental Protection Agency
               Cincinnati, OH 45268

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                 Disclaimer
  This report  has  been reviewed  by the Industrial
Environmental   Research  Laboratory,  U.S.
Environmental Protection Agency,  and approved for
publication. Approval does not signify that the contents
necessarily reflects the  views and policies of the U.S.
Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorse-
ment or recommendation for use.

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                  Foreword
  When energy  and material resources are extracted,
processed, converted, and used, the related pollutional
impacts on our environment and even on our health often
require that new and increasingly more efficient pollution
control  methods be used. The Industrial Environmental
Research  Laboratory-Cincinnati (lERL-Ci) assists in
developing  and  demonstrating  new  and improved
methodologies that will meet these needs both efficiently
and economically.
  These proceedings cover the presentations from the
"Third EPA/AES Conference on Advanced Pollution
Control for the Metal Finishing Industry." The purpose
of the conference was to inform industry on the range and
scope of research efforts underway by EPA and others to
solve  the pressing  pollution problems of the metal
finishing industry. It is hoped that the content of this
proceedings  will stimulate action to reduce pollution by
illustrating approaches  and techniques high-lighted  by
the  wealth  of  excellent papers  presented  at this
conference. Further information on these projects and
other  metal finishing pollution research can be obtained
from  the  Nonferrous  Metals  and  Minerals  Branch,
lERL-Ci.

                                 David G. Stephan
                                          Director
       Industrial Environmental Research Laboratory
                                        Cincinnati
                       ill

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                              TABLE OF CONTENTS


 INTRODUCTION
    George S. Thompson, Jr. and J. Howard Schumacher, Jr	 1

 INTRODUCTION TO CONFERENCE
 EPA WELCOME TO THE THIRD CONFERENCE ON ADVANCED POLLUTION CONTROL
  FOR THE METAL FINISHING INDUSTRY
    William A. Cawley 	2
 "STATUS OF AES RESEARCH"
    J. Hyner	 3
 STATUS OF EPA RESEARCH
    George S. Thompson, Jr	5
 SESSION I
 WASTEWATER
 STATUS OF WASTEWATER REGULATIONS
    Robert B. Schaffer	9
 POTW REMOVAL CREDITS AND REVISED CATEGORICAL PRETREATMENT STANDARDS
    Jon L. Olson and Richard W. Eick	 11
 SESSION II
 WASTEWATER
 ELECTROCHEMICAL REACTOR AND ASSOCIATED IN-PLANT CHANGES AT
  VARLAND METAL SERVICE, INC.
    Edwin Roof	 16
 THE APPLICATION OF SEPARATION PROCESSES IN THE METAL FINISHING INDUSTRY
    Peter Crampton	23
 DOES RECOVERY  REDUCE TREATMENT NEEDS?
    F. A. Steward	30
 REGENERATION OF WASTE CHROMIC ACID ETCHING SOLUTIONS IN AN
  INDUSTRIAL-SCALE RESEARCH UNIT
    L. C. George, D. M. Soboroff and A. A. Cochran	33
 LIQUID ION EXCHANGE IN METAL RECOVERY AND RECYCLING
    Lawrence V. Gallacher	37
ACHIEVING EFFLUENT CRITERIA—NOT FINAL ANSWER
   A. F. Lisanti and R. Helwick	43
SESSION ill                '; •;
SOLID WASTE
LUNCHEON PRESENTATION: THE RESOURCE CONSERVATION AND RECOVERY ACT
   Rebecca Hanmer	45
RESOURCE CONSERVATION AND RECOVERY ACT
   Kurt W. Riegel	48
REPORT ON THE RESULTS OF THE AES/EPA SLUDGE CHARACTERIZATION PROJECT
   Kenneth R. Coulter	51

 SOLIDS REMOVAL AND CONCENTRATION
    Richard W. Grain 	56

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MAKING HAZARDOUS WASTES NONHAZARDOUS
   Robert B. Pojasek, Ph.D	63

RADIOCHEMICAL STUDIES OF THE LEACHING OF METAL IONS FROM
  SLUDGE BEARING CONCRETE
   John D. Mahoney, Elaine A. Dwyer, Walter P. Saukin and Robert J. Spinna	65
SESSION IV
SOLID WASTE
STABILIZATION OF HEAVY METAL WASTES BY THE SOLIROC PROCESS
   J. M. Rousseaux and A. B. Craig, Jr	70
ROUTES TO METALS RECOVERY FROM METAL FINISHING SLUDGES
   Anil Mehta 	76
SOLVENT RECOVERY FOR THE SMALLER COMPANY
   C.  Kenneth Claunch 	80

SESSION V
AIR POLLUTION AND ENERGY RECOVERY
VOC INCINERATION AND HEAT RECOVERY - SYSTEMS AND ECONOMICS
   Roy M. Radanof	84
ENVIRONMENTAL AND ENERGY BENEFITS ACHIEVABLE BY COMPUTER CONTROL OF
  AIR FLOW IN BAKE OVENS
   Matt Heuertz	92
EMISSIONS FROM OPEN TOP VAPOR DECREASING SYSTEMS
   Charles H. Darvin	98
V.O.C.  CONTROL EFFORTS BY A HEAVY DUTY TRUCK MANUFACTURER
   Edward W. Kline^.,	102
SESSION VI
CENTRALIZED TREATMENT
CENTRALIZED TREATMENT AND DISPOSAL OF SPECIAL WASTES IN THE
  FEDERAL REPUBLIC OF GERMANY
   N.  Roesler	104
EPA'S CENTRALIZED TREATMENT PROGRAM
   Alfred B. Craig, Jr., and George C. Cushnie Jr	115
HAZARDOUS WASTE MANAGEMENT FACILITIES: THE SITING PROBLEM AND
  POSSIBLE SOLUTIONS
   Frank Boni	132

GROUP TREATMENT—OPTIONS AND ECONOMICS
   Erich W. Salomon and Edward H. Comfort	135

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                                             INTRODUCTION
   "The  Third  EPA/AES  Conference  on Advanced
 Pollution Control for the Metal Finishing Industry" was
 held in Kissimmee, Florida, on April 14- 16, 1980. This
 broad scoped colloquium  was jointly designed  by the
 American  Electroplaters'  Society  and  the   U.S.
 Environmental Protection Agency's Nonferrous  Metals
 and Minerals Branch.  The  primary objective of this
 conference was  to continue the dialogue established at
 the First EPA/AES Conference (1978) and strengthened
 at the Second EPA/AES Conference (1979) between key
 members of the EPA and the metal finishing industry.
 The  proceedings,  contained herein,  of this  Third
 Conference reflect the primary points of the gathering:
 the  status  of  EPA's  wastewater  and solid  waste
 regulations, and both  EPA's and industry's  research
 efforts to effectively address the ramifications of these
 regulations. Air  pollution and energy recovery, financial
 pollution control alternatives, and centralized treatment
 of metal  finishing residuals were also discussed at the
 conference and  reports of  this  work  appear in these
 proceedings.
  The program  of the  conference was broken into six
 segments:  wastewater,  regulation and  research; solid
 waste,  regulation  and research;  an   exchange  of
 viewpoints between members of the government and
 industry;  air  pollution and energy recovery, regulation
 and research; centralized treatment as an alternative  to
 on-site treatment of waste water and solid waste residuals;
 and concurrent sessions addressing detailed inquires on
 the  pollution  problems  and finiancial alternatives
 available to the metal finishing industry. Since attendees
 of the  first  and second  conferences  placed  extreme
 emphasis  on  wastewater and solid waste, the first two
 segments  of  the  Third  Conference were structured  to
 provide  conference  attendees  with a  detailed
 understanding of the potential impact of current and
 future regulations in these two important environmental
 areas, as well as the research being conducted to address
 wastewater and  solid waste pollution problems.  Key
 EPA officials, representing EPA's water and solid waste
 regulatory offices and  research  office,  described the
 procedures by which EPA  prepares and promulgates
 regulations and conducts research activities having direct
 impact  on   metal  finishers. Industrial participants
 described, in  various  papers, examples of current and
 potential  solutions  to  wastewater  and solid  waste
 pollution problems.
  The third segment, entitled 'Exchanging Viewpoints"
 was  conducted  during  an  evening  session.  A  panel
 comprised of EPA officials and industry representatives
 opened the floor to a free discussion  in order to permit
 EPA and industry to commonly and clearly understand
those  research needs  considered  to  be of paramount
 importance.  This objective was  fulfilled  as  the needs
 became evident during frank discussions between  the
 attendees and the panelists.
   The fourth segment of the conference  discussed air
 pollution regulations and research activities, as well as
 the  energy recovery potential available  to  the metal
 finishing  industry.  Besides a discussion of current and
 pending air  pollution regulations by an EPA official,
 various EPA research projects structured to produce
 cost-effective technologies  and  approaches  to  the
 primary metal finishing industry's air pollution problems
 were described.
   Centralized treatment, the fifth segment, was discussed
 during the entire final session of the conference. Papers
 on  this  viable  alternative  to  on-site  treatment  of
 wastewater and solid waste were presented by industrial
 representatives  from the  United States.  Centralized
 treatment as practiced in West Germany since 1964 was
 described by an  esteemed  colleagues  from the Federal
 Republic  of Germany.  EPA's research  program  on
 centralized treatment was also discussed in detail.
   A group of concurrent sessions comprised the sixth
 segment of the conference. Individual groups of speakers
 representing the various  sessions  of the  conference
 provided  detailed commentary on  his or  her area  of
 expertise. Attendees of the conference  were permitted to
 attend  the  various  detailed  concurrent  sessions
 depending upon their interests.  A special room  was
 established for individual attendees to receive detailed
 information  on pollution control  financial alternatives.
   This conference,  attended by more  than 600 persons
 interested in  the environmental problems faced by metal
 finishers,  was considered an extraordinary success. The
 principal purpose of the conference, to continue a fruitful
 dialogue between industry and EPA, was achieved. The
 high-priority  research  needs  of the  industry  were
 identified  and solutions to  pressing problems are being
 sought—some jointly—by EPA and AES.
   The proceedings are published here  in order that the
important  material  presented at the  Conference can
benefit as  many people as possible interested in solving
the  intricate  problems  inherent  in  metal  finishing
processes.  These proceedings contain  the presentations
made by  representatives of various  EPA regulatory
groups affecting the metal finishing industry, as well as
presentations by parties actively addressing  research and
development in this same industrial area.
   The EPA and the AES are pleased to have cooperated
in  this   mutual  endeavor  which  has  improved
communications  and which should  foster  continued
research resulting in sound technical  solutions to the
environmental problems of metal finishers.
            George S. Thompson, Jr.
                      Chief
   Nonferrous Metals & Minerals Branch, EPA
            J. Howard Schumacher, Jr.
                Executive Director
       American Electroplaters' Society, Inc.

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          EPA Welcome to the Third Conference
                 On Advanced  Pollution  Control
               For the  Metal  Finishing  Industry
                                      William A. Cawley*
  I would like to extend to you EPA's "welcome" to this
Third Conference on Advanced Pollution Control for the
Metal Finishing Industry. In addition, I offer a special
thanks to Howard Schumacher and his staff, to Mike
Murphy and to other AES members who have worked
diligently to make the conference possible. We hope our
efforts  are successful  in  providing  you  with  an
understanding and an awareness of EPA's regulatory and
R&D activities impacting the metal finishing industry.
  We in EPA view this conference as a timely and cost-
effective tool  for us to obtain the metal  finishing
industry's evaluations of and recommendations for our
ongoing and planned  programs.  Consequently,  this
conference is a critical activity in EPA's metal finishing
R&D program.  This  year we  again solicit  your
participation and comments after each presentation and
particularly at the Tuesday evening discussion session.
Members of  my staff who are responsible  for the
development and implementation of the metal finishing
R&D program and who are present at our  Conference
are George Thompson, Chuck Darvin, Fred Craig, and
Anil  Mehta.  George and his people  will  be  actively
soliciting  your comments  and  reactions  during  this
conference's discussion periods  and through informal
contacts. We  intend  to compile this information and
distribute it  to you for  comment along with the
conference proceedings.
  The major goal of the R&D efforts is to develop and
evaluate pollution control methods that are broadly
applicable to the metal finishing industry, that present
cost-effective options for meeting regulations, and that
minimize or eliminate intermedia transfer of the
pollution problem.
  At our first EPA/AES conference we attempted to
bring to you the status of EPA's total efforts in air, water,
solid waste,  and  toxic  substances which  are likely to
impact  your industry.  Last year  we focused on the
Agency's water and solid waste programs which we feel
will have the greatest impact in the near term. This year,
our primary  emphasis is on water and solid waste with
lesser  emphasis  on air,  financial  alternatives  and
centralized treatment.
  I personally would like to encourage you to critically
evaluate the ongoing and planned R&D activities in view
of the major R&D goal I have stated, and to provide your
candid  comments on  each  project and the overall
program direction. Your participation is essential to the
success of the conference and to EPA and the industry's
efforts to control pollution from the metal finishing
industry.
  Once again, I am glad you are here and hope that I have
the  opportunity to meet many of you during the next
three days.
•William A. Cawley
 Deputy Laboratory Director
 Industrial Environmental Research Laboratory
 Cincinnati, Ohio

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                        "Status of AES Research'
                                               J. Hyner*
  Even before our nation became conscious of the effects
of pollution  upon  our environment, the AES had
sponsored research projects with the goal of rendering
harmless the  effluents  and solid  waste  of the  metal
finishing industries.
  Of the nine AES research projects currently active, five
are directed towards solving some aspect of pollution. Of
the five pollution oriented projects, two are co-sponsored
by the EPA.
  I'll review the reason for choosing each active pollution
project and bring you up to date on the current status of
each.
PROJECT NO. 48
Title: The  Effect  of Anions  on the Precipitation  of
Heavy Metal Ions from Electroplating Wastewater
Site: Columbia University; Project Director: Dr. Huk Y.
Cheh; Co-sponsored with the EPA
  All who have effluent purification systems operating
have learned that theoretical hydroxide precipitation of
heavy metal ions is not always obtained. You  have
learned that even though today you may be meeting your
standard for copper, or  zinc, or  any  other  metal,
tomorrow you cannot do better than 5 ppm.  We long
suspected that assorted anions often interferred with and
prevented complete precipitation of the  heavy metals.
The  purpose of Project  No. 48 is to determine which
anions commonly used in plating interfere with complete
precipitation, by  what  mechanism  does interference
occur, and most  important,  how do we control  or
neutralize  the  interferences  so  that  theoretical
precipitation can occur, allowing us to successfully meet
EPA  standards. Although authorized a  year ago, the
project  is just getting started since  Dr.  Cheh was  on
sabbatical leave for a year. Isidore Cross, a past president
of AES  is chairman of the project committee. In talking
to him  this morning I learned that his committee is
complete and ready to start getting the project underway.
Phase I is expected to be completed some time during the
coming  year.

PROJECT NO. 49
Title: The Effect of Electroplating Wastewater Sludge as
an Admixture on the Physical Properties of Concrete
Site: Manhattan College; Project Director: Dr. Robert
Spinna;  Not co-sponsored with the EPA
*J. Hyner, Chairman
 AES Research Board
 Whyco Chromium Company, Inc.
 Waterbury Road, Thomaston, CT 06787
  Purifying our wastewater is now a common practice in
the  plating industry  and,  within  the next  few years,
should be universal. The problem of what to do with the
tons of metal salts removed from the contaminated
rinsewaters has become pressing. Most of the metals have
been removed in the form of insoluble hydroxides. What
shall we do with them? The ideal solution, of course,
would be to remove the metals from the sludge and reuse
them.  This  is  technically  possible  with  current
knowledge.  However,  until  much   more tonnage
accumulates, it is not really economically feasible. Even
though  a few  hundred  tons of sludge  may  be  a
tremendous amount to a plater, it is very little to a refiner,
so that of necessity very few refiners would be needed in
the  United States. The cost of transporting sludge great
distances is tremendous and, at  current metal  prices,
makes refining uneconomical.
  What can we do with our sludge for the next few years -
for the time it takes all shops to get on stream and maybe
enough  sludge  is generated to make area refineries
economically feasible, if ever?
  We have known for several years that the Japanese and
Europeans have encapsulated and immobilized sludge in
concrete. Cement is alkaline, insoluble, and theoretically
could serve to keep the metal hydroxides from dissolving
and leaching back into the environment. Our project was
not set  up to repeat the  work of the Japanese and
Europeans, whose interest was only in  finding a place to
safely dispose of sludge without concern for the strength
and properties of the altered concrete.  We are interested
in the concrete as well as in giving the platers a safe
disposal site in almost every city in this country. If
incorporation of some sludge in the concrete does not
alter the properties of the concrete, every batching plant
theoretically becomes a disposal site.  The head  of our
project, Dr. Spinna, is a professional engineer whose
specialty is concrete and construction. Associated with
him are chemists whose specialties are applied to leaching
and the chemical structure.  Tomorrow, Dr. Mahony,
who has  been conducting leaching  studies  using
radioactive tracers will report on his results.
  Tests to date on the strength and properties of sludge-
modified-concrete show that the incorporation of sludge
containing 11A - 2% solids into concrete to replace water
does not appreciably alter the  physical properties of
cured concrete, and  the concrete  is so insoluble that
leaching of metals is in the order of parts per billion—
completely safe to the environment.
  This project has not been co-sponsored  by the EPA.
That agency was a bit skeptical in the early days of the
project. Now that the first two phases of study have been
so successful, we will again submit a proposal for further

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work to the  EPA and to  the  Office of Solid Waste.
Hopefully this  time  around, the AES, the EPA,  and
Portland  Cement Association  will  be able to work
together. We desperately need safe, convenient disposal
sites for our sludges generated by the clean up of other
effluents.
PROJECT NO. 51
Title: Immiscible Rinsing of Plating Solutions
Site:  United  Technologies  Research Center;  Project
Director: Dr. Jordan Kellner; Not co-sponsored with the
EPA
  The best way to control pollution is to close the loop
and not discharge plating waste, most of which comes
from  rinsing after  plating. During the  last few years
reverse  osmosis, electrodialysis, Donnon  dialysis, ion
exchange  and evaporation have been both researched
and employed to capture and reuse the plating solution
rinsed off the plated parts. Incidently, more of the closed
loop type of methods were researched under EPA grants,
some with AES cooperation. All have been used to some
extent.  All  the  above  processes require  expensive
equipment and skilled attention, which often makes the
process  economically  unattractive,  even  though
technically satisfactory.
  If we had a non-aqueous immiscible solvent that would
rinse  off the  plating solution and then allow the rinsed
solution to either sink or rise, the solution could easily be
returned to the plating tank for reuse without  further
treatment. This may be a long shot, but if successful, an
ideal way to save solution and solve a pollution problem.
In research to date, twenty-five different solvents were
mechanically shaken to react the solvent with chromium
plating solution—a solvent would be useless if it rinsed
well  but  contaminated the  chromium bath.  Of the
twenty-five   initially  tested,  five  were  chosen  for
continuing tests because of low reactivity with chromium
solution, low cost,  toxicity  and  boiling  points.  The
chosen  solvents  also  represented  different  chemical
structures  consisting  of  saturated,  long-chain
hydrocarbons, saturated,  branch-chain  hydrocarbons,
an aromatic ether  and an aromatic hydrocarbon. Tests
with the five solvents are now underway, and some results
should be available by July, 1980.

PROJECT NO. 53
Title: Development of a Reactor to  Eliminate Cyanide in
Electroplating Effluents
Site:  Ontario Research Foundation; Project  Director:
Al Cadotte; Not co-sponsored with the EPA
  Chlorine   oxidants   and  peroxides  are  almost
universally used  to destroy  cyanides.  They are very
expensive  and  sometimes  dangerous  to  handle.  A
cheaper, technically sound method to destroy cyanides
used in the metal finishing industry would be universally
welcomed.
  It's been known for many years that cyanides can be
destroyed by  hydrolysis when heat and pressure are
applied.
  Experiments at the Ontario  Research  Foundation
have   indicated  that  heating  a  cyanide-containing
solution, for example, a copper cyanide plating bath, in a
sealed container to 210°  C, approximately 450° F, for
only a few minutes will effectively destroy the cyanide.
  Based  on its laboratory work,  Ontario  Research  is
building  a flow-thru reactor of standard stainless steel
pipe to determine the feasibility of using this principle in
practice.
  I am personally tremendously enthusiastic about this
project. I believe that it will be successful and that within
a relatively short time will be the means of saving metal
finishers thousands of dollars annually and, at the same
time,  eliminating  cyanide very  effectively from  our
effluent.


PROJECT NO. 55
Title:  Sludge Characterization
Site:  Centec Corporation; Project  Director: Mr. Paul
Minor; AES/EPA Cooperative Agreement
  The EPA  required  more  information  about  the
leaching  characteristics  of electroplating sludges,  and
with the information gained, it would have the basis for
establishing safe,  segregrated disposal  sites for solid
waste. It also required a rapid on-site test of sludge so that
a disposal site operator  could quickly test a batch of
sludge sent in for disposal and determine whether or not
it could safely be dumped at the disposal site.
  Twelve different sludges, from twelve  plating plants
covering most of possible types of sludges produced by
the plating industry, have been collected,  leached and
analyzed.  I believe that  when the testing program  is
completed,  results will  show that metal hydroxide
sludges from plants with satisfactorily operating effluent
systems can safely be placed in segregated  landfill sites
with no  potential harm  to the environment.  Analysis
showed that the  only soluble metal ions  were in the
interstitial liquid and that the amount of leached metal
was so minute that leaching of the interstitial water in the
rains would yield concentrations below levels acceptable
for discharge.
  Future work will research more of what happens to the
interstitial water and will also investigate models for a
satisfactory disposal site.
  The sludge characterization and concrete projects will
be covered in more detail later in the program.

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                            Status of  EPA  Research
                                         George S. Thompson, Jr.*
INTRODUCTION
  Fourteen  months  have  past  since  our  Second
EPA/AES Conference. During this time period, many
things  have happened affecting the metal  finishing
industry. Not only has the  cost of raw materials and
energy skyrocketed, but environmental regulations have
been - or are shortly to be - established for the air, water,
and  solid  waste pollution  generated by the  industry.
Pretreatment  regulations  for  electroplaters  were
promulgated in September of 1979. Revised BAT will be
proposed in  the near term. Regulations for solid waste
generators should be out before the end  of this month.
Regulations  specific  to solvent degreasers and other
sources of volatile organic compound (VOC) emissions
will shortly be established.
  Where does research fit into such a complex and fast
movirtg situation? Our purpose is well established - to
provide, in a timely way, cost-effective technologies and
approaches  through  research, development,   and
demonstration that will meet or surpass the requirements
established by air, water, and solid waste regulations. For
those of you who  were  not  present at  the Second
EPA/AES Conference or who have not seen the Second
Conference "Proceedings," I represent the research arm
of EPA -  EPA's Office of Research and Development
(ORD). My Branch,  the  Nonferrous  Metals  and
Minerals Branch (which during the past  14 months has
received a  new name resulting from a reorganization) is
part  of one of ORD's field laboratories - the Industrial
Environmental  Research  Laboratory  -   located in
Cincinnati, Ohio. Now in our fifth year, we are chartered
to conduct R&D on the air, water, and  solid waste
discharges from  a number of industries including  the
mining and milling of nonfuel minerals; the smelting and
refining of nonferrous metals; the manufacture of glass,
ceramics,  cement and lime;  and,   of  course, metal
finishing and fabrication.

Recent Achievements and Research  Goals
  The  last 14 month period  has  seen an increased
understanding of our metal finishing research goals
related to solid waste and an overall attempt to accelerate
our efforts to establish more timely answers.  Before I
describe these goals, allow me to list our achievements
since we last met:
  • Publication of three reports for broad  dissemination:
    -"Environmental  Pollution Control Alternatives:
"George S. Thompson Jr., Chief
 Nonferrous Metals and Minerals Branch
 Industrial Environmental Research Laboratory
 U. S. EPA, Cincinnati, Ohio 45268
      Economics of Wastewater Treatment Alternatives
      for the Electroplating Industry"
    - "Summary Report - Control Technology for the
      Metal Finishing Industry - Evaporators"
    - "Summary  Report  -  Control and Treatment
      Technology for the Metal Finishing Industry -
      Sulfide Precipitation
  • Completion of data  package  for  Mechanical
    Products  and  Electrical/Electronic  Products
    Industries
  • Completion  of  the  EPA/AES  Cooperative
    Agreement   on  Metal  Finishing  Sludge
    Characterization
  • Completion of EPA-Inhouse  Metal  Finishing
    Sludge Stabilization Study
  • Completion of Solvent  Degreaser  Evaluation
    Project
  • Completion of Computer Program for Quantifying
    Energy Savings From Increased Operating Lower
    Explosion Limit (L.E.L.) on Paint Curing Ovens
  • Completion of First Two Phases of Centralized
    Treatment Program
  • Input to  EPA's Office of Water  Planning and
    Standards (OWPS) on Structure and Detail of "8-
    City Seminar Series for Electroplaters"
  • Publication of R&D Reports

  The  current  goals of our metal finishing research
program and our plans and methods to meet these goals
follows.

Goal I  - Complete Investigations on Inplant Changes

  Many metal finishers have stated that such in-plant
changes as water conservation steps, reducing chemical
usage, etc. are "old  hat" or "common knowledge." This
knowledge is, of  course,  new to some  of you, but
certainly not to all of you. I have quickly become aware of
the significance of  in-plant changes and how  these
changes have an effect  on wastewater and solid waste
pollution generation and the economics of treatment
and/or disposal. Our efforts to identify in-plant changes;
to measure their effectiveness in reducing wastewater
volume, wastewater pollutant loading, chemical usage,
and sludge generation; and to ascertain the associated
costs to implement these in-plant changes continues. Ed
Roof or Varland Metals Services will be describing the
various in-plant changes used at his job shop during this
afternoon's water session. I would  also like to  make
reference to Clarence Roy's presentation at the Second
EPA/AES  Conference (published  in "Proceedings")
which discussed in-plant changes and their impact on
sludge generation.

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  Whether you  already have wastewater control (i.e.,
concentrating techniques)  and/or treatment techniques
in-place or are now "shopping around" for solutions,
please go back  to your metal finishing processes and
evaluate the  impact  of  utilizing  in-plant  changes.
Hopefully,  we will have a detailed report on in-plant
changes reviewed and published by August, 1980.
Goal II — Provide Wastewater Control and Treatment
Technologies That are Easy to  Operate, Non-capital
Intensive, Do Not Produce a Sludge, etc.
  This goal is (and may continue  to be) one of our most
difficult goals to achieve; many parties in both the public
and private sectors have attempted to achieve this goal
over the past decade with only partial success.
  Our approach  to  achieving this  goal changed  14
months ago. Previously, we sought novel ideas and then
funded or co-funded laboratory-scale, bench-scale, pilot-
scale, and  full-scale  demonstrations.  Some  of our
previous research efforts were stopped due to some form
of failure or limitation of a technical or economic nature.
Others proved successful.  The  primary reason  for
changing to a different approach  was TIME.
  Wastewater  regulations and  guidelines have  been
established for portions of the metal finishing industry;
regulations and guidelines for the  remainder of the metal
finishing  industry will  be set in the near future. The
compliance  period  for  some   metal  finishers  (e.g.:
electroplaters  discharging  to  Publicly-Owned
Treatment Work: [POTW's]) has started and this goal
must be achieved soon to have impact.
   Our new aproach to achieving this goal is three-fold:
   • Clearly identify  existing solutions. Identify their
     applications, as well as their limitations. Document,
     by evaluating full scale applications, their capital
     costs and operating and maintenenace costs as well
     as operating problems.  Broad dissemination is used
     to "spread the word" as far as possible so that the
     largest  number of readers  will benefit  from our
     evaluations.  Our  "Alternatives   Report"  and
     "Summary Report   on Evaporators"  (described
     under  "achievements"  above) are  examples. We
     have a similar  summary report  on ion exchange
     nearly  ready for review and publication.  We have
     also completed several major efforts on soluble and
     insoluble sulfide precipitation; a summary report on
     this treatment technology has been published and
     copies of this full color report are  available at the
     EPA table. A decision  was reached several months
     ago to prepare  a  brief status  report  on reverse
     osmosis,  since this  control technology does have
     some excellent  applications.  We do not plan to
     perform further RD &  D on this technology.
   • Complete RD & D on promising approaches that
     have excellent potential.  Several technologies fall into
     this  category. One  is  an electrochemical reactor
     which we have been demonstrating at Varland Metal
     Services.   Ed  Roof, who  is  discussing in-plant
     changes this afternoon, will also describe the status
     of the demonstration on cadmium, zinc cyanide and
     chloride,  copper cyanide,  chromium,  and nickel
     plating wastewaters. We  are also completing a
     demonstration of electrodialysis. Last  month, we
     funded an effort to  develop an anionic membrane
     for   Donnan  dialysis;  this  technology is  very
    promising  and  if  such  a  membrane  can  be
    successfully developed, we will enter into a full-scale
    demonstration.
  • Evaluate "Emerging Technologies" for wastewater
    control  and/or  treatment.   At  our  Second
    EPA/AES Conference, I explained portions of what
    became our Emerging Technology Program. This
    program  is  currently  being  implemented.  The
    purpose of this program is simply stated. We are not
    aware  of numerous wastewater (this program also
    addresses air and solid waste, but  current emphasis
    is  on  wastewater)  control   and   treatment
    technologies and alternatives. This program should
    maximize our awareness. An "Awareness Bulletin
    for Metal Finishers" will,  on a  bimonthly  basis,
    canvas numerous trade (and related)  publications
    and provide  to the reader a synopsis of findings.
    Copies  of  the  first  "Awareness  Bulletin"  are
    available at the EPA table for review and comment.
    Besides the  bimonthly  Bulletin, the  Emerging
    Technology  Program is structured in three phases:
    (1)  Identification of  candidate  emerging
    technologies, usually through  received telephone
    calls  and other  forms of  correspondence, and
    prioritizing  of these candidates  for  "third  party
    evaluation"  based  on established  prioritizing
    criteria; (2) Detailed or "third party" evaluations of
    the highest prioritized technologies requiring field
    visits and  possible sampling; and (3) Dissemination
    of  results  by  means  of  a  Summary Report
    publication. The technologies we are looking for are
    those that are either operational on a very small scale
    (one or two plants) or are close to commercialization
    and, in both cases, are potential national solutions to
    aiding us in reaching our goal.

    As I did at the  Second EPA/AES Conference, I
    solicit  any "Emerging Technologies" that you may
    be  aware  of so that we can consider them for our
    ongoing program.

Goal III - Provide Guidance to Upgrade Existing End-of-
Pipe Wastewater Treatment Facilities and to  Improve
the Design of New Facilities.
  Several research activities are  either completed  or
nearly completed that should allow us to achieve this
goal.  One  activity has  just been  initiated  that will
hopefully address methods of upgrading existing end-of-
pipe systems for better wastewater pollutant removal and
sludge formation.
  For  new  end-of-pipe neutralization/precipitation
systems, a Manual of Practice has been prepared and has
undergone  extensive review. Publication of this manual
is forecasted by July,  1980. Even though it is not a design
manual, it  has been prepared to provide  guidance to
metal finishers (and other industrial users  who employ
conventional neutralization/precipitation  technology)
when  faced with the need to purchase  and/or fabricate
such a system. Sludge is also addressed in  this manual.
  Our recently published Summary Report on Sulfide
Precipitation  describes  soluble  sulfide  polishing
techniques  that  can be added to existing  hydroxide
systems to achieve better effluent quality. Similarly, the
Summary Report on Ion Exchange, which is currently in
first draft form, provides detail on the application of i^n
exchange  for  polishing  conventional  end-of-pipe
treatment technology effluents.

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   A new research activity has just been initiated which
 resulted from the recently completed EPA/AES Sludge
 Characterization project. Current plans for this  new
 activity  call  for field visits back to the electroplating
 plants visited during the initial 3-phase project. The end-
 of-pipe wastewater treatment systems at each plant will
 be scrutinized to determine possible "upgrading" steps,
 such  as  removing  certain influents,  using different
 neutralizing chemicals and/or flocculants, etc. Screening
 of possible changes will be conducted in the laboratory
 and verification  of the  most promising will be field
 demonstrated.  Since the quality and  quantity of the
 sludge generated by the wastewater treatment system is
 directly  related to the design  and/or operation of this
 system  (conclusion  resulting  from EPA/AES  Sludge
 Characterization study), this new research activity could
 provide methods for improving effluent quality, chemical
 usage, and sludge quality and  quantity. More detail on
 this new project is provided under Goal IV.

 Goal IV - Provide Solutions to the Metal Finishing
 Industry's Sludge Problem.

   The approach to achieving Goal IV is quite complex.
 The  EPA/AES  Cooperative Agreement  on  Metal
 Finishing Sludge Characterization  has been completed.
 Ken Coulter will  provide  more detail on this  project
 tomorrow. The AES and EPA have jointly defined a
 follow-on laboratory/field project. This project has been
 partially funded  this year; we hope to complete the
 funding  of  this  project  next year through another
 cooperative agreement with the AES.
   We have just initiated  a project on documentation of
 current practices in "sludge usage/waste exchange." Our
 investigation will cover the United States, Japan  and
 Western Europe. The finding and documenting of several
 environmentally safe uses of sludge may lead us to
 additional uses and may also prove to be part of our goal.
   We are currently establishing an inhouse program to
 determine the  best  metallurgical  techniques for cost
 effective recovery of metals from single and multiple-
 metal sludges. The concept is simple  and justified - the
 sludges being investigated are hazardous sludges due to
 their toxic nature; their toxicity is caused by their metal
 content. Therefore, the metal content must be reduced to
 a degree that makes the sludge non-toxic. Two product
 streams  will  be  produced - recovered  metals  and
 nonhazardous  sludge.  Anil  Mehta  of  our staff is
 responsible for this inhouse effort and  will explain his
 approach on  Tuesday.
  Another potential solution which may enable us to
 reach our solid waste goal is Centralized Treatment. This
 alternative would not only  prove to be technically and
 economically  advantageous for  metal  finishing
 wastewater, but also for sludge. As witnessed from our
 investigation  of West German Centralized Treatment,
 segregated retention areas for metal  hydroxide  sludge
 have been established  for  waste exchange and metal
 recovery.  As  the volume of "retained" sludge grows,
 metals recovery becomes more  economically viable and
the Centralized Treatment concept is the best collection
and "retention" alternative available.
  One last R & D activity, which is now in  its second
year, is  a combination of Centralized  Treatment and
metals recovery from cadmium-bearing sludge. This is a
cooperative agreement with the International Lead/Zinc
 Research  Organization. The  approach under
 investigation  is  the  collection  of  metal  finishers'
 cadmium-bearing sludges and transport to a primary zinc
 smelter  (cadmium  is  a  byproduct  of primary  zinc
 production) and  the subsequent recovery of cadmium
 values in the zinc production circuit.
 Goal V  - Provide Centralized Treatment to the Metal
 Finishing  Industry  as   a   Technically  Sound  and
 Economically Viable Alternative to On-site Wastewater
 Treatment and Sludge  Disposal.
   Our metal finishing Centralized Treatment Program is
 now in its 13th month. Fred Craig, of my staff, and  I
 originally envisioned this program as a four phase effort,
 with the third phase calling for  demonstration and the
 forth phase evaluating and disseminating  the results of
 the demonstration.  Fourteen months ago, Fred Craig
 described  this four-phase effort and  some  attendees
 commented that our program on Centralized Treatment
 was dynamic, but not timely enough for metal finisher's
 needs. What we have now, after having completed the
 first two phases is sufficiently detailed  information on
 Centralized Treatment to act as a catalyst for you to
 implement the concept. Not enough can be said about
 this alternative for metal finishers - the findings of the
 first two phases of this program are very enlightening
 and, in summary, I believe that  the necessary tools are
 now  available for  you to  determine if Centralized
 Treatment can provide  a partial or total solution to your
 wastewater and/or  sludge  problem.  Note  on  your
 conference program that the entire Wednesday morning
 session is devoted to Centralized Treatment; I urge you to
 attend this session - it will prove to be quite enlightening.
 Goal VI - Provide Techniques for the Control of Volatile
 Organic Compound (VOC) Emissions
   The use of solvents  in  the metal finishing industry,
 whether  in solvent degreasers  or as part of a paint
 formulation, leads to the atmospheric discharge of VOC.
 Some metal finishing operations are major sources of
 VOC.
   We currently have a number of research activities,
 including  some  field  evaluations  and full-scale
 demonstrations, focused toward  the above goal.
   One major activity on solvent degreasers is essentially
 completed and Chuck Darvin of my staff will report on
 the important findings  of this study during the Tuesday
 afternoon "Air Pollution and Energy Recovery Session."
 Chuck provided interim status of this activity at both the
 First  and  Second  EPA/AES  Conferences.  If  you
 currently use degreasers, or plan to use them in the future,
 I strongly suggest that you listen to Chuck's presentation
 - especially since the New Source  Performance Standard
 for this VOC source will soon be proposed.
   We are currently fabricating a scrubber, which uses
 surfactants as the scrubbing media. This summer, we will
 test it at our inhouse facility followed by field testing at a
 Cincinnati firm.  If  you  operate a company  in the
 Cincinnati area that discharges VOC from metal coating
 operations and would like to test the surfactant scrubber
at your plant, please contact us.
   We  have  set  up a microprocessor  at  the EPA
Conference display table. The demonstration from this
microprocessor is part of  a joint  project with  the
Department of Energy. The overall goal  of this joint
effort is to monitor and  control the lower explosion limit
(LEL) of paint bake oven atmospheres in order to safely
increase the LEL.  By increasing the LEL from 5-10% to
25-50%,  significant  fuel savings will result and VOC

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destruction can be economically practiced with primary
and secondary heat recovery. Trie controlling mechanism
will be an inexpensive microprocessor. A presentation on
this  joint  EPA/DOE  project will be made during
Tuesday afternoon's air session. If you are interested in
the economic incentives resulting from increasing your
curing oven's  LEL, please visit  our display table and
witness  the economic  calculations. If you  have the
necessary data on your curing oven(s), please provide this
data to us and the economic calculations will be made for
you. We are hoping that this display  will  give you the
incentive to seriously consider the objectives of this
project; we  are  also  currently  looking  for  a
demonstration plant.
   Recently, we initiated a "fact finding" study on fugitive
VOC emissions from paint application. If you are aware
of any  novel  techniques for collecting fugitive  VOC
emissions from this source, please contact  us.
   Several   other  metal finishing/VOC activities are
nearly  complete,  such as  our  environmental/energy
evaluation  of a gas recirculation system. Some of these
projects address new coating formulations that are low in
solvent  content.
   In the near term, we plan to conduct RD & D on "low
temperature incineration." If you have any research ideas
on this  subject, please contact us.

Goal  VII - Disseminate All Pertinent Findings. Ensure
the Highest of Quality in these Findings
  The metal finishing industry has  more  plants, both
large  and  small/captive  and  job, than  any  other
industrial category. When pertinent findings are made,
they must  be  broadly disseminated in order to have
visability and,  in-turn, impact.
   We have thus far published three full color reports for
broad dissemination that address wastewater control and
treatment technology for metal finishers (solid waste is
also covered, but to a lesser extent).  Two of these three,
published last June, have already been distributed to over
10,000 individuals  and companies both in the U. S. and
abroad. These reports are part of our Summary Report
Series for  Metal  Finishers.  Two  more reports will be
published  to temporarily complete  this Series: one on
"Ion  Exchange"  and  the  other   on  "Emerging
Technologies".  We plan to prepare others, especially
when pertinent  solid waste/sludge findings are made.
  We also publish reports  for  most of our  research
projects.  A complete list (as of January 1979) of these
publications  is contained  in  the  Second  EPA/AES
Conference "Proceedings".
  Besides dissemination through written materials, we
feel  that  workshops,  seminars, and conferences are
important tools, especially for 2-way communication.
Our First and Second EPA/AES  Conferences have
afforded  us the  opportunity to not only understand your
problems, but to also gather your research ideas.
  The second part of this goal is to achieve high quality
output. Again, this Conference allows us to describe our
current and planned activities and our  major areas of
emphasis. As stated in this year's (and last year's) "EPA's
Opening   Remarks", EPA's Office  of  Research  and
Development views this  Conference as an excellent
source of critique and constructive criticism. The quality
of our products can never  exceed  the  quality of our
program goals and the approaches to achieve these goals.
  We attempt to have  our "final drafts" reviewed and
commented on  by as many interested parties as possible
from both the public and private sectors. If you would
like to  provide constructive  criticism  of  any  of the
activities described in this presentation, please contact us.
Lastly,  I offer our products  to  the  metal finishing
industry's trade magazines for "peer  review."
  During the past  nine months, we have been  deeply
involved   with  other   EPA  Offices  and  industrial
representatives  in structuring what we term the "Eight
City Seminar  Series for Electroplaters". This series,
which should start during  the last  week in August, is
designed to  explain technological wastewater and solid
waste control  and treatment alternatives, as  well as
discussions   on  financial   alternatives  available to
finishers. For more information on this seminar series,
please  contact  my office or  Ms. Francis DeSalle at
(202) 426-7874.
  In  conclusion,  I  have  attempted,  during  this
presentation, to describe the goals of EPA's air, water,
and solid waste metal finishing research program. I solicit
any comments  you may have on these goals and on our
approaches to achieve  them.

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               Status of  Wastewater  Regulations
                                           Robert B. Schaffer*
   I appreciate the opportunity to spend this time with
 you every year.  As in our previous two conferences, I
 have some new information to provide to you. I consider
 these descussions with you to be a very important part of
 my job. Although getting the regulations out on time is
 important, dealing  with  the regulated public through
 interchanges and discussions is also a very  important
 aspect of providing good regulations. As with last year
 and the year before, I arrrgoing to continue to give you a
 preview of what is to come. I will also discuss the final
 pretreatment guidelines  as they were promulgated last
 fall. Also, I will tell you about all the  changes we have
 subsequently made to the promulgated regulations.
   As you may know, the pretreatment regulations, after
 they were promulgated, were challenged by the National
 Association of Metal Finishers. The main issues brought
 forth have  been discussed  in  a  continued  spirit  of
 cooperation for accomplishing  good  regulations. We
 believe that the problem areas have been resolved and the
 necessity to  proceed with litigation has been eliminated.
 We are currently in the  process of putting together the
 results of those negotiations and I am going to discuss,
 unofficially at least, the changes to the regulations, which
 will be  proposed shortly. If they are finalized without
 significant change after a proposal and comment period,
 our agreement is that the litigation will be dropped.
   The most significant changes will be  in the revision of
 the total cyanide limitation. The total cyanide limitation
 will increase from 0.8 to 1.9 milligrams per liter. Second,
 we are going to eliminate the 30 day limits. In their place,
 we will establish four day limits. This change was made to
 eliminate the possibility of extensive and burdensome
 monitoring  requirements. The  new cyanide  numbers
 were taken from monitoring data and, even though they
 differ numerically, still describe  the performance of the
 technology.
   We are also going  to  remove the requirements for
 monitoring  that were  included in the  promulgated
 pretreatment regulations, primarily  because  of the
 difficulty in specifying good monitoring requirements for
 all unique  situations  that  exist.  The  requirements
 themselves, will not be in the categorical standards but
 will be included  in the general pretreatment regulations
 as  a guide to  those  who  will  be  implementing  a
 pretreatment program.
   Finally, and of significance, the Agency has agreed not
 to propose more stringent pretreatment regulations for
 several years. The reason, which I'm sure is obvious to
•Robert B. Schaffer, Director
 Effluent Guidelines Division
 U.S. Environmental Protection Agency
you, is to give a target that is going to stand still for a
while.  Because  it takes  time  to get  the  necessary
equipment purchased, shaken down, and installed and
because  you need some  flexibility in financing, the
Agency has agreed to let these regulations  stand for
several years. Don't ask me what several years means, I
don't have  the  answer to  that  question.  Generally,
however, a period of five  years  is not  an unreasonable
expectation. The direct dischargers with  a permit have
that amount of time. I think that kind of philosophy is
going to  follow  through  in this particular instance;
however, no commitment has been made on either side.
Let me make that clear.
  There are, of course, still questions associated with the
electroplating pretreatment regulations and the general
pretreatment regulations that Steve Schatzow mentioned
earlier in his keynote speech. These regulations are in the
process of being  modified.
  We continue to be  concerned  over the impact on
municipal sludges, the severity and the magnitude of that
impact, and how to determine whether it is a good idea to
have  heavy metals in municipal sludge.  Within the
Agency, there have been a few different  philosophies and
conflicts  which we finally referred to as "big piles" and
"little piles." Some feel that it is  very important to have
very tight control over toxic materials and  that they
should not be  indiscriminately  discharged  into the
municipal systems to contaminate municipal sludges, a
practice that would prevent their disposal in ways that are
potentially beneficial or more economical. On the other
hand, others believe  that these  materials are more
manageable if   kept  in   municipal  systems  and in
municipal sludges, because then you would have a better
handle on  where they are. You would know that the
sludge is within a particular jurisdiction and who has the
responsibility for proper disposal of the solids. The issue
is still under discussion, and I expect it will be for a while.
  We initiated a study on municipalities which I refer to
as the 22nd industry. BAT is looking at toxics from 21
industries. We decided that there might be another one - a
pretty good size  one - that is the municipalities. So we
initiated the study to look  at the occurrence and fate of
toxic pollutants in municipal treatment systems. We have
completed about  40 to 50 percent of that study and have
the  results back on 30 percent of  it. We  tried to select
representative  cities  that  have  properly  operated
treatment systems that are achieving the  secondary
treatment requirements for municipal discharges. We
tried to pick plants that had different types of treatment
technologies installed,  such as trickling filters, activated
sludge, etc. We also tried to select plants  with differing
geographical locations  and with different amounts of
industrial inputs.

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   The results so far have been very interesting. With no
 surprise, we  find that the heavy metals are consistently
 removed in the municipal systems, up to the point where
 they are concentration limited (i.e., solubility limited).
 But assuming that a significant amount of metals enter
 the plant, the level that is discharged  is reasonably
 independent  of the type  of industrial or non-industrial
 city that is being sampled. The effluent concentration of
 heavy metals from municipal treatment systems is pretty
 much the same whether it is from a "dirty city" (i.e., one
 having a lot of industrial discharge to be treated) or from
 a  more domestic residential city where  the  industrial
 contributions are  relatively low. There  is however a
 small, but identifiable pass through in the  effluent from
 cities with a  higher influent concentration. We are also
 finding that  the organic  materials that are entering the
 POTW's are  also removed to a very high degree. Part of
 our reason for summarizing some of the initial data is to
 see what kind of impact this will have on the credit policy
 that is included in the general pretreatment regulations.
 To see what kind of consistent removals we might find, it
 turns out that, in highly industralized cities, there are
 slightly higher removal efficiencies than in nonindustrial
 cities. This generalization is very broad. For most of the
 heavy metal  pollutants that are in the influent that you
 would be discharging and that we are concerned over, a
 rough average of about  50 percent removal  efficiency
 through  the municipal  system  has  been  initially
 determined. This percentage varies somewhat; but from
 metal to metal, from city to city, it looks like 50 percent.
 By pooling all of the data we have,  we will have the
 necessary confidence for determining- credits. Much of
 this information,  as  well  as  additional  work  of
 determining  the  effect  of toxic  pollutants on the
 municipal  treatment systems,  will be presented at the
 Water  Pollution Control Federation  meeting in Las
 Vegas in October. We expect that our POTW study will
 be completed and the results will be presented along with
 the results of some research work that is to be conducted
 on organics and heavy metals.

  Looking into the future and ensuring my invitation to
our next EPA/AES conference, I will now explain our
current  BAT efforts  on  the  Mechanical  Products
Industry. Electroplating is often found to be part of this
industry.  The industry  covers  about 40,000 facilities
ranging from automobile and aircraft manufacturing to
very small manufacturers of mechanical  and electro-
mechanical products.  We are finding that the greatest
volume  of discharge comes from the electroplating
operation at these plants. We still haven't decided exactly
how to go about subcategorizing this very complex
industry. Also, we will have to decide how to handle what
we  call combined  treatment,  that is the mixing  of
electroplating wastewater with  wastewater from other
sources  prior to treatment. This "comingling" of waste-
water, treating  each process source separately, has in
most  situations  a  sound  engineering   basis.  But
comingling also causes  great  consternation amongst
people in the Agency for very good reason. Since most of
the  technologies  that   we  are talking  about  are
concentration limited, mixing wastewaters that contain
heavy metals  can lead to a scenario where many more
toxic materials can be discharged. Since the treatment
technology is concentration limited, independent of the
influent concentration, the increased discharge results in
an  increase in  total pounds that are  released to the
environment. This issue is still under active discussion
within the Agency.
  The daily maximum numbers that are in the regulation
at present are:
           Copper
           Chrome
           Nickel
           Zinc
4.5  mg/1
7    mg/1
4.1  mg/1
4.2  mg/1
  Our study  is  showing -  and this DOES include
combined treatment systems - that we are able to achieve
lower metal concentrations with better technologies that
we are evaluating. Such technologies include chemically-
assisted clarification. We are finding that copper can be
reduced from 4.5 to 2.5 mg/1, chrome from 7 to 2.5 mg/1,
nickel from 4.1 to 0.7 mg/1, and zinc from 4.2 to 1.4 mg/1.
These are the kinds of differences we are seeing in our
preliminary evaluation of our data base. When we have
our technical report together, as an informal rule making
process that  we  go through,  we will circulate the
information to you for your  review. This step is not a
formal ruling; it will be your opportunity to comment on
the technical aspects and technical  merits of our data
base. One thing that is important, though, is that we do
not have a great deal of information. We are looking at
many other industries that have similar types of problems
and  are pooling the data. For example, the inorganic
chemicals industry has many heavy metal problems that
are similar; we also have applicable treatment technology
data from that industry.
  Also  of interest  to  you,  is a  "treatability" manual
currently being developed under a joint effort between
my  office  and   EPA's Office   of   Research  and
Development  under the  direction of Bill Cawley, who
spoke to you earlier. Our data on organic and inorganic
pollutants  is  being  utilized  to  describe how various
technologies will perform when properly operated. This
manual will be used in the field  by regional and state
officials  to  assist  in  making  determinations where
guidelines may not directly apply to a given problem or to
a  given industrial  facility.  The manual should  be
available by mid-year. It will not be published as a formal
regulation; it will be made available for comment and I
urge you to take a look at it.
  I have mentioned organics briefly. In our BAT study,
we have found significant amounts of some toxic organic
pollutants being discharged. We feel that the source of
these organics is the dumping of solvents. These solvents
should be placed in a drum for disposal or, when we reach
a point when it  is economical,  let's go with  resource
recovery.  We are going to try to  discourage solvent
dumping.
  Finally,  Steve  Schatzow  mentioned  our  interest in
incentives, in  innovative technologies with the goal of
approaching zero discharge. I heard this morning that the
goal is not impossible.  I head this morning that your
association is  looking in  that direction. We are not in a
position nor do we want to be in a position of saying that
we  must  reach zero discharge  by  1985. But we are
extremely interested in these kinds  of pursuits and  we
fully encourage them. It is also encouraging to me that we
have the opportunity or  the options down the road of
having economical ways to approach the goal of the Act.
  I hope that when I see you again next year, you have all
your treatment in,  all  your pretreatment programs
operable,  and that you will  be looking forward to the
solid waste regulations.
                                                    10

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                     POTW Removal  Credits and
   Revised Categorical  Pretreatment Standards
                                 Jon L. Olson and Richard W. Eick*
 INTRODUCTION
  The  Sanitary  District of  Rockford  wastewater
 treatment plant provides a secondary-type treatment for
 an  estimated  connected population of approximately
 200,000 people  and  wastewaters  from  some  500
 industries  belonging  to the U.S.  Environmental
 Protection  Agency's 21  subcategories.1 Based upon
 District information, it has been determined  that 38
 industries   can  be  defined  as   belonging  to  the
 Electroplating  Subcategory and  presently discharge
 approximately  8  MOD  to the  sanitary  sewer
 (approximately 20-25% of treatment plant flow).
  In the early 1960's the  District final effluent, which
 received primary and  trickling filter-type  secondary
 treatment, contained a considerable amount of cyanide
 (see Figure 1). As a result, there were a few fish kills in the
 receiving stream, which required action by the Sanitary
 District and,  consequently, by Rockford Industry. In
 1966, the District approved a 2.0 mg/L cyanide limit on
 all  industrial discharge  to the sanitary sewer.  The
 addition of a secondary wastewater treatment system by
 the District in 1969 improved the amount of cyanide
 removed in the treatment process,  resulting in lower
 effluent cyanide concentration. In 1974, Ordinance 309
 went  into  effect and lowered  the cyanide limit to  1.2
 mg/L and included for  the  first  time heavy metal
 limitations on industrial discharges.
  Ordinance  309 industrial discharge  limitations for
 cyanide and  heavy metals  were calculated  by the
 District's staff who took into consideration,  for the first
 time, the amount of pollutant removed by the wastewater
 treatment  plant.  The  District derived the following
 pollutant discharge formula, which was incorporated
 into Ordinance 309:

           Pollutant Discharge Formula
       Effluent Standard
       100-(%) Removal
X
  SDR Flow
Pollutant Flow
            _ mg/L Pollutant Discharge
            ~~         Limit
Where:
  EFFLUENT STANDARD is the applicable Federal,
State  or  Local  Effluent standard  for  any specific
pollutant, in mg/L.
  % REMOVAL is the average percent removal of the
specific pollutant effected  by  passage through  the
*Jon L. Olson, District Director
 Richard W. Eick, Plant Operations Manager
 Sanitary District of Rockford
                            treatment works during the preceding twelve months
                            based upon daily analysis.
                              SDR FLOW is  the average flow received at  the
                            treatment works during the preceding twelve months, in
                            millions of gallons per day.
                              POLLUTANT FLOW is the total of Hows from all
                            known  sources which contain or may contain  the
                            pollutant for which the calculation is being made, in
                            millions of gallons per day.
                              POLLUTANT  DISCHARGE  LIMIT  is  the
                            maximum  allowable concentration  of  the  specific
                            pollutant which may be discharged to a public sewer, in
                            mg/L.
                              The industrial pollutant discharge limits, as calculated
                            by the above formula and incorporated into Ordinance
                            'General Pretreatment Regulations for Existing & New Sources of Pollution.
                            Federal Register June 26, 1978, Part IV. Appendix C.
                            Figure 1—Final Effluent Cyanide Concentration (annual averages).
                                            FINAL EFFLUENT CYANIDE CONCENTRATION

                                           . (ANNUAL AVERAGES)
                                                11

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Table 1

Ordinance 309/341 Pretreatment Standards

Pollutant
Cyanide (by distillation]
Copper
Cadmium
Nickel
Chromium (Total)
Chromium (Hexavalent]
Zinc
Iron
Lead
Ordiance 309 passed in
Ordiance 341 passed in
Pollutant
Ordinance
1.2
17.6
2.0
6.7
21.8
3.6
16.5
56.0
1.5
1974
1976
Discharge Limit mg/L
309 Ordinance 341
0.9
17.6
2.0
6.7
21.8
3.6
16.5
56.0
1.5


309 (present Ordinance 341), is given in Table I. These
limitations have been and are presently being applied to
industries regardless of their subcategory.
  The 1979 annual average cyanide and heavy metals
concentrations in the final effluent are given in Table II
along  with  their respective treatment  plant removal
efficiency. This data has been  collected  since 1973 and
collection will continue in the future, with some changes
to reflect the Proposed Amended General Pretreatment
POTW sampling  requirements.2
  The USEPA's  removal  credit  formula  to revise
categorical  standards  was  given  in  the General
Pretreatment  Regulations  of  June 28,  1978  Federal
Register as follows:

    Revised Categorical  _  Categorical Standard
         Standard       ~         1 - r

   Where "r" is the percent of the pollutant (expressed as a
fraction) that is removed by the POTW.
   Although the  basic concept of applying the POTW
removal  credits  to  an  industrial  discharge  limit is
common to both the District and the USEPA methods,
the overall formula and application differs considerably.
The major difference, as outlined in Table III, will result
in stricter limits under the  USEPA method. This is, of
course,  only  conjecture at this time and assumes the
approval of the  removal credit concept by the USEPA
method.  In order  for the  Sanitary District to receive
conditional  revisions  of  categorical pretreatment
standards,  if at all, there is a  considerable amount of
work to be completed by Industry, the USEPA, and the
POTW. Once all the data and reports are completed, an
appropriate decision  can be made by the USEPA as to
the applicability  of removal credits.

Procedure for  Revising Categorical Pretreatment
Standards to Reflect POTW  Removal
  The October 29, 1979 proposed amendments3 to the
General   Pretreatment  Regulations  outline  seven
provisions  to be included in a POTW application for
revised categorical pretreatment standards.
  (Section 403.7 (b)(2)(v)(i-vii). The Sanitary District of
Rockford has indicated to the  USEPA, Region V , in a
letter and general method outline dated December 18,
1979, of its intention to so apply. It is important to the
Sanitary   District's  pretreatment  program  and  to
'Federal Register Volume 44, No. 210. October 29, 1979, Section 403.7(c)(2)(ih)
and (iv).
'Federal Register Volume 44, No. 210 October 29, 1979.
Copper
Month
January
February
March
April
May
June
July
August
September
October
November
December
Average
mg/L
0.27
0.25
0.42
0.33
0.30
0.13
0.14
0.14
0.08
0.09
0.12
0.24
0.21
%
Rem.
80.0
79.2
53.8
54.8
66.3
83.8
84.9
84.9
90.0
89.4
87.9
71.1
77.6
Table II
Final Effluent Quality and Percent Removal
Total
Cadmium Nickel Chromium 6+ Chromium
mg/L
0.07
0.07
0.08
0.07
0.07
0.03
0.02
0.02
0.01
0.02
0.02
0.05
0.04
%
Rem.
63.2
69.6
57.9
58.8
58.0
88.9f
92.0
91.3
94.7
91.7
90.0
73.7
77.5
mg/L
0.21
0.18
0.18
0.15
0.14
0.12
0.12
0.09
0.11
0.14
0.16
0.20
0.15
%
Rem.
34.4
28.0
28.0
16.7
33.3
33.3
42.9
47.1
56.0
56.3
50.0
52.4
33.9
mg/L
0.10
0.08
0.08
0.07
0.04
0.02
0.022
0.021
0.02
0.04
0.04
0.05
0.05
%
Rem.
85.1
88.7
79.5
75.0
89.5
95.0
94.2
95.5
95.0
92.2
91.3
86.1
88.9
mg/L
0.05
0.04
0.04
0.03
0.02
0.02
0.002
0.001
0.00
0.00
0.00
0.01
0.02
%
Rem.
90.9
77.8
63.6
70.0
80.0
93.9
93.3
90.0
100.0
98.3
98.0
85.7
86.8
for 1979
Zinc
mg/L
0.70
0.61
0.85
0.66
0.56
0.29
0.29
0.33
0.21
0.26
0.34
0.45
0.47
%
Rem.
76.2
80. 1
61. 5
55.1
72.8
88.1
88.1
86.0
87.8
86.0
81.7
75.9
77.6
Iron
mg/L
0.68
0.22
0.38
0.36
0.21
0.18
0.18
0.24
0.14
0.20
0.33
0.32
0.29
%
Rem.
93.3
95.0
89.0
87.0
94.2
95.6
95.6
97.9
95.7
93.4
92.4
90.5
93.3
Cyanide
mg/L
0.029
0.021
0.026
0.033
0.040
0.031
0.031
0.051
0.062
0.055
0.061
0.061
0.042
%
Rem.
90.3
93.6
91.0
84.3
86.7
87.6
87.6
83.0
73.0
80.4
80.9
74.6
84.2
                                                     12

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                                                    Ts ble III
              Comparison of USEPA and SDR Pretreatment Standards Determination and Application
                  Item

   \. Basis of Pollutant Limit
   2. Removal Efficiency, "r"
   3. Number Days "r" Determined
   4. Pollutant Concentration Consistency
   5. Industrial Sampling Point

   6. Industrial Flow Diluted at POTW

   7. Contaminated POTW Sludge

   8. Limitation for 24-hour Composite
   9. Limitation for Grab Sample
             SDR Method

Treatment Plant NPDES Limitations
Annual Average
365 Days
Same Limit for All Industrial Categories
Limit Applied End of Pipe from Entire Plant

Accounted for in the Pollutant
 Discharge Formula
Not Considered, Applying Sludge to Landfill

Limit as Calculated by Formula
5 Times the 24-hour Limit
          USEPA Method

National Technology Based Standards
Average of Lowest 50% of Values
48 Days (12 Days per Season)
Pretreatment Limits Vary with Each Category
Limit Applied After Fretreatment for
 That Category
Dilution by POTW not considered in Formula

To be Considered, Must Meet 405 Sludge
 Regulations
Limit as Calculated by Formula
Same as Composite Sample
Rockford Industry to determine, as quickly as possible,
which  pretreatment standards  will apply:  revised or
existing categorical standards.  It is also hoped that an
early application will help to clarify some of the existing
problems  and  unknowns.   The  following  seven
provisions. A  thru G, will be part of the Districts's
application for revised categorical standards.

A.Industrial Reporting Requirements
  These reporting requirements apply in  the case of
Rockford industry to the Electroplating Subcategory
since they are presently the only group in Rockford with
applicable final pretreatment standards. If these reports
are not submitted by April  6,  1980, the applicable
electroplating industry will not be eligible for the revised
pretreatment standards, should they be granted  by the
USEPA. The seven elements of electroplating reporting
requirements are given below:
  1. The name and address of the Industrial User.
  2. The location of such Industrial User.
  This  is the  address  of the  Industrial Plant that is
discharging the electroplating  wastewater  (if different
from plant headquarters).
  3. The nature,  average rate  of  production,  and
standard industrial classification of the operation(s).
  It is assumed that the SIC code and average rate of
production would be useful should the  District choose to
utilize mass limitation based upon volume of product.
  4. The average and maximum flow of the discharge(s).
  The District also requires that the industry submit not
only the total flow of each discharge, but also the volume
of categorical  process water, which in  the case  of the
electroplating  industries  would be rinse wastewaters
resulting  from operations  of  alkaline cleaning,  acid
pickling,  stripping, coloring,  and waste which  comes
about  from spills, batch dumps, and scrubber blow-
down.
  It is  the District's understanding, at this time, that
tumbling operations prior to plating (i.e. deburring) will
not  be  included  in  the term electroplating process
wastewater. The wastewater from this operation will be
considered  under the  group  18,  "Machinery  and
Mechanical Products Manufacturing."4
                        5. The nature and concentration of pollutants in the
                     discharge from each regulated process.
                        This should include not only the concentration at the
                     end of the  pipe,  but also the • concentration  of the
                     electroplating process wastewater (or after pretreatment
                     of such wastewater, if available).
                        6. A  statement  indicating  whether  Pretreatment
                     Standards are being met and, if not, whether additional
                     operation and maintenance (O and M) and /or additional
                     pretreatment is required.
                        As written, the electroplating industry must respond as
                     to  whether  they  are   meeting  the  electroplating
                     pretreatment  standards.   However,  if the  Sanitary
                     District has received approval from the USEPA to use
                     the revised standard, then the Industries would respond
                     to these. Also, these comparisons must be made not at the
                     end of  the  pipe,  but at  the point  where  all  the
                     electroplating process  wastewaters are combined.
                        7. If additional pretreatment and/or O and M will be
                     required,  the shortest  schedule by which the Industrial
                     User will  provide such additional pretreatment.
                        To answer items 6  and 7  it is  important that the
                     eleetroplater  know  as  soon  as  possible  which
                     pretreatment standards will have to be complied with: the
                     existing  electroplating pretreatment standards  or the
                     revised standards.
                     B.The Sanitary District must comply and submit data in
                     accordance with the requirements of 403.7 (c)(l)-(7).
                        1. The District must supply a list of pollutants for
                     which the revised pretreatment standards are requested.
                        2. Treatment   plant  influent  and   final   effluent
                     concentrations  for  the   above  pollutants  must be
                     presented on a daily basis using 1979 data. These influent
                     and final effluent samples were taken on a 24-hour basis
                     at a frequency of 6 grabs per hours using a refrigerated
                     FMC  composite sampler. However,  this  past data,
                     although comprehensive, is not entirely compatible with
                     those of the proposed General Pretreatment amendments
                     because of sampling techniques employed.
                         a. The influent and final effluent composite samples
                        were not taken proportional to flow. This was changed
                        this year under completion of an addition to the plant
                        activated sludge  system, and  also  a new influent
4Federal Register June 26, 1978, Volume 43, No. 123 "General Pretreatmenl
 Regulations . . .," Appendix.
                      Federal Register June 26, 1978, Volume 43, No 123 "General Pretreatmenl
                      Regulations . . .," Section 403.7 (c)(l-7).
                                                      13

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   sampling  room  which   was  part  of  the  new
   administration building expansion.  Henceforth, the
   samples will be taken proportional to flow.
     b.  The  final  effluent  composite  samples  must
   incorporate the concept of detention time into the
   sampling sequence. This has not been done in the past,
   i.e. both the influent and final effluent composite
   samples were pulled daily at 12:00 midnight. This was
   changed  on  January  1,  1980 when  the influent
   composite sample was changed at  12:00  midnight,
   while the final effluent was pulled at 10:00 a.m., i.e. a 10
   hour  average  POTW  retention time was used.
   Henceforth, the influent and final  effluent composite
   samples will be taken as described above.
     c.  The cyanide analyses were made  daily on the
   usual 24-hour  composite samples rather than on the
   grab  samples as required by 403.7 (c)(2)(iv). The grab
   sample techniques can be utilized in the future for
   comparision with the present method of determining
   the removal efficiency.
   The  Sanitary District believes that the data on the
 above  influent-final  effluent  samples   collected  as
 described above,  will give an accurate and demonstrable
 indication of the pollutant removal efficiency,"especially
 since 365 individual days' removal efficiencies will be
 examined for each pollutant using an IBM 370 computer.
 The program  will  be written  to compare consistent
 removal determined by ... "the average of the lowest 50
 percent of removal  measured. .  . ."6
   It is the District's  belief that, because of the prodigious
 amount of influent-effluent data, the 1979 data used will
 adequately demonstrate the removal  efficiencies.
   3. The  Sanitary  District will supply a list  of all the
 industries that are presently known to be members of the
 Electroplating Point Source Category and which of the
 pollutants each discharges.
   4. The  proposed  revised Electroplating Pretreatment
 Standards that will apply to the above industries will be
 submitted. The formula, as given in 403.7 (c)(4)(i) shall be
 used to calculate  the revised pretreatment standards.
     Revised Categorical  __
          Standard
Categorical Standard
        1-r
Where "r" is the percent of the pollutant (expressed as a
fraction) that is removed by the POTW.
   5.  A  table  listing  the  concentrations  of  the
approximate  pollutants   as  found   in  the  sludge
thickening tank  underflow  sludge for  1979 will  be
submitted. This underflow sludge, which is composed of
50% primary and  50% waste-activated sludge, is sampled
on  a  composite basis  every  two  weeks  and  the
appropriate analysis made.
   The  above sludge is pumped  to the vacuum filter
building for conditioning with lime and ferric chloride,
followed by dewatering with  Komline Vacuum  Filters.
The resulting cake is disposed of in an Illinois EPA
approved  landfill. This vacuum filter cake is also sampled
and analyzed every two weeks for these same pollutants.

   6.  A description  of the  POTW's  current  sludge
disposal methods will be supplied to the USEPA. Any
current sludge disposal permits with the IEPA  will be
included with the description.
"Federal Register October 29, 1979; Volume 44, No. 210, Section 403.7 (a)(I).
  7. The District will certify that, except where noted,
the pollutant removals and the revised standards were
determined  as outlined  in the  USEPA regulations.


C. Industrial Compliance Schedule with the POTW
  Electroplating type industries who are not able to meet
the electroplating categorical pretreatment standards (or
revised pretreatment standards, if known and approved
by the USEPA) must enter into a compliance schedule
with the Sanitary District of Rockford. This compliance
schedule  should culminate with pretreatment systems
that  will insure compliance by October 7,  1982. In this
regard, it is imperative that the electroplating industries
know whether  revised  pretreatment  standards will  be
allowed.  Industrial failure  to submit  a compliance
schedule or to meet any of its scheduled events will mean
the industry will not be eligible for revised pretreatment
standards.
  Another similar issue is whether the BAT pretreatment
standards,  yet  to  be promulgated,  will  have stricter
standards  for  the  typical  electroplating  pollutants.
Industry needs to know and so does the POTW.


D.  The  Sanitary  District  Must  Apply  for  the
Pretreatment Program Approved in a Timely Manner
  This will be done and, in fact, the majority of the data
regarding  Rockford Industries and  toxic pollutants,
especially cyanide and  heavy metals, has already  been
collected. The Sanitary District is waiting for a State
Grant approval so  that  an  inspector can be hired  to
concentrate on organic priority pollutants and Rockford
Industry.  It is expected  that  this yet to-be-hired
individual will make inspections of all Rockford industry
with a knowledgeable industrial representative from each
industry.
  This information along with the effluent, and sludge
organic priority pollutant analysis (which was already
completed separately by the USEPA and the  University
of Washington, Seattle) should give us a good picture in
this area.
  The  Sanitary District must enter into a compliance
schedule for development of the pretreatment program
which will be made part of a revised Illinois EPA NPDES
Permit. This compliance  schedule will serve  as a guide
post to gauge the District's progress toward pretreatment
program approval.

E. Termination of Conditional Removal Credits
  The conditional revised standard will be terminated by
the control authority if the District does not comply with
the following:
  1.  Unable to maintain  removal  efficiencies
  2.  SDR does not apply for the pretreatment program
in a timely manner.
  3.  The District does not comply with the sludge use as
defined in Section 405 guidelines or any other guidelines.
  Should the District fail to comply with 1,2, or 3 above,
the  industries  must  achieve  compliance  with  the
applicable pretreatment standards before the  prescribed
time period  for those standards.
                             F.  Company Failure to Comply
                               If  a  company  fails  to comply with its  reporting
                             requirements, or fails to submit or meet the compliance
                             dates, then the conditional standards for that particular
                                                    14

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company are terminated. That company must meet the
applicable pretreatment standards  in the required time
period.

G.  The Sanitary District must submit  the name and
address of each Industrial  User  that has  been given
conditionally revised  discharge limits each December
31st. Upon revocation, the District must submit, to the
control authority, the  industrial information as given in
II,  A,  7-7. The Industry limits will than revert to the
categorical pretreatment standards.

CONCLUSION AND DISCUSSION
  Under the new pretreatment regulations, the Rockford
industries belonging to Electroplating Subcategory will
be  required  to meet stricter  discharge  limits  than
presently imposed by District Ordinance. To what extent
will depend upon whether POTW removal credits will be
allowed. It is imperative for Industry and the POTW that
an  early decision on this concept be  made by the
USEPA.
  The  issue of contaminated POTW  sludge  resulting
from cyanide and heavy metal removal is  one of the
primary factors influencing this concept. It is hoped that
the 405 sludge regulations will define the sludge disposal
options that are available to the POTW. It would appear,
from many previous comments by the USEPA, that only
agricultural  application  of  municipal  sludge  will be
considered. What is to happen  with the municipalities
that are presently using approved incineration or landfill
disposal techniques? The decisions made by the USEPA
on the  desired sludge "quality", once made,  must be
applied uniformly and equally throughout the United
States.
   Another problem that the USEPA must resolve is the
application of  different  pretreatment  concentration
limits of a similar pollutant from different subcategories
to a single industrial discharge. If this single company has
a  common pretreatment  system,  which  pretreatment
standards are applicable?
   The POTW will be  responsible for submitting its
Pretreatment  Program  to  the  control  authority for
approval in a  timely manner. The Sanitary District of
Rockford is committed to this and expects to receive
approval by the July 1983 deadline. If past experience is
any guide, there  are  many as yet unknown problems
ahead for the  District in the fair, reasonable,  and  just
application of these regulations to Industry.
   The Industries, as  required, will  have  to  install
appropriate pretreatment systems to meet the discharge
limitations to the sanitary sewer. Industry should, at this
point, consider two very  important factors that  will
determine  the.ultimate success  of  their pretreatment
system: (1) if necessary, have an experienced consultant
help with the design engineering. Checking with his past
clients could  be  informative.  (2)  Have a qualified
pretreatment system operator to run the operation  and
make  him responsible for  the  effluent  quality. This
operator must regard the effluent quality as his final
product.  After all is  said  and done, it is the  effluent
quality that is of primary concern and the reason for the
Pretreatment Program.
                                                    15

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       Electrochemical  Reactor and  Associated
 In-Plant Changes at Varland  Metal Service,  Inc.
                                           Edwin Roof
INTRODUCTION
  This report will describe the background and present
status of the Joint Demonstration Project sponsored by
the Metal Finishers Foundation and the Environmental
Protection  Agency  at  Varland   Metal   Service,
Incorporated, Cincinnati, Ohio.
  The purpose of this demonstration  project  is: to
evaluate  the use  of a unique  electrochemical system
designed to reduce  pollutants  from an electroplating
plant to meet EPA regulations; to evaluate the capability
of the system to recover the valuable metals in the rinse
water for re-use in the plating processes; and to minimize
the formation of sludge.

Varland Metal Service, Inc. - Background
  Varland Metal Service, Inc., is an electroplating job
shop.  The  Company  was founded  in  1946 and
incorporated in 1947 by Curtis M. Varland, W. Wilson
Loveless, and Edwin Roof.
  The Varland plant is a multi-process  plant with the
following processes: (1) automatic barrel cyanide zinc; (2)
hoist barrel zinc, cyanide and chloride, (3) hoist barrel
cyanide copper, bright nickel, tin, cyanide cadmium,
cyanide brass;  (4) automatic barrel cyanide copper and
bright nickel; (5) hoist phosphating, barrel and rack; (6)
hoist rack zinc and cadmium, cyanide; (7) automatic rack
cyanide zinc; (8) rotary barrel chromium; (9) basket and
rack chromium; (10) mechanical plating, zinc, cadmium,
and  tin;  (11)  chromating,  bright dipping  of  brass,
passivating of stainless steel and other similar processes.
  The Varland plant has approximately 47,000 total
square feet of floor space. Annual  sales are  in  the
$2,500,000  to  $3,000,000   range; total employment
numbers 60 to 70.
  In 1974, a major step towards furture compliance with
local and  federal anti-pollution  regulations  was  the
establishment  of a modern  laboratory for analysis of
waste streams. Included  was an atomic absorption
spectrophotometer for  analysis  of metal discharges.
Later in  1974,  an engineer  was employed to set-up  a
comprehensive  sampling and  analytical program to
determine  what  steps  should   be  taken   to meet
regulations.
  By the end of 1976, it was clear that much work needed
to be done. City of Cincinnati revised regulations of Sept.
*Edwin Roof, Executive Vice Pres., Chemical Engr.
 Varland Metal Service, Inc.
 Cincinnati, Ohio
1, 1976 with a compliance deadline of July 1,1979, called
for the following limits:
   CN-T
   CN-A
     Zn
10 mg/L
2mg/L
6 mg/L
Cr-T
 Cd
 pH
 6 mg/L
 3 mg/L
6.0 to 10.0
  Final  EPA pretreatment limits  had not yet  been
promulgated, but they were expected to be even tighter.
By contrast a typical analysis of the wastewater at that
time was
PPM IN
Usage, gal
216,000
pH
7.0
24 HR COMPOSITE SAMPLE
CN-T
15.8
Cd Cr Cu Ni
1.0 11.8 3.3 6.7
Zn
37.5
  It  was obvious that some type of waste treatment
should be installed. Accordingly, an intensive real estate
acquisition program was pursued to buy some additional
land adjacent to the plant and a successful campaign was
waged at City Hall, in  spite of some  neighborhood
resistance, to get the newly acquired land rezoned so that
waste treatment facilities could be installed.
  By the end of 1977, an engineering firm was retained,
and  preliminary  work was begun on design  of  a
conventional treatment plant to treat 300,000 gallons of
waste per day, to allow for growth. We felt we already
had good water conservation with Dole flow restrictor
valves on all rinses, and with all rinses  being counter-
flow. At this point in time, we received the opportunity to
participate in the  MFF-HSA research project.

HSA REACTORS LIMITED - BACKGROUND
  HSA  Reactors Limited of Toronto,  Canada  is  a
company formed  to research, manufacture and market
these electrochemical systems. The system is based upon
research undertaken in 1974 by Drs. Das Gupta and Fleet
in the Department of Chemistry at Imperial College,
University of London, England. The system features the
use of an electrochemical cell with graphite electrodes
designed to increase  the mass transfer  rates and  thus
increase the efficiency of the metal removal process.
Early in 1975 this work was brought to the attention of
Ian Kennedy, now the  President  of HSA Reactors
Limited, by Dr. A. Barringer, of Barringer Research,
Toronto, an  alumnus  of  and visiting professor at
Imperial College. During the latter part of May, with the
help of numerous scientific and engineering consultants,
an  extensive test  program was  designed for the
electrochemical system. This test program was conducted

-------
at  Imperial College under  the  supervision  of Mr.
Kennedy  in  early  June,  1975,  with  completely
satisfactory results. An agreement to finance the ongoing
research, development and commercialization of the
system was rapidly  concluded, and the company was
incorporated on July 19, 1975.
  The cell was orginally envisioned as having three
possible practical  industrial  applications,  namely
pollution control of metals in solution, hydrometallurgy,
and organic synthesis. At an early date, HSA decided to
focus its efforts on pollution control applications.
 BACKGROUND OF THE
 JOINT DEMONSTRATION PROJECT
  In June, 1976, at the AES Convention in Denver, Ian
 Kennedy  met  Simon  Gary,  of  Scientific  Control
 Laboratories, Chicago, and they discussed the invention.
 Mr. Gary recommended  that HSA  contact NAMFs
 Metal  Finishers Foundation, and this was done. As a
 result  of this contact, Bill Crawford of Chrome-Rite
 Company of Chicago and Ed Durkin of Advance Plating
 Company, Cleveland, went to Toronto to investigate the
 use of these cells in the metal finishing environment. They
 were both impressed with the possibilities for the use of
 this cell in pollution  abatement in the metal finishing
 industry and invited Mr. Kennedy to appear in December
 of 1976 at a meeting of the trustees of the Metal Finishers
 Foundation in Atlanta. Based on a  presentation by Mr.
 Kennedy and  confirmed  by  the observations of Mr.
 Crawford and Mr. Durkin, the trustees of the  MFF
 appropriated  $15,000  towards  the  cost of  a
 demonstration project in the  Chrome-Rite plant  in
 Chicago.
  In June, 1977, at the Chrome-Rite plant, industrial
 scale  research reactors were  demonstrated  by  HSA
 personnel. All analytical work evaluating  results was
 done by  Scientific Control Laboratories. At the same
 time, a full scale plant assessment  was done by HSA
 personnel, locating and classifying the point sources of
 pollutants in the Chrome-Rite plant.
  The  results of the demonstrations were phenomenal.
 This was later documented by Mr.  Kennedy in a paper
 presented  to  the  first   EPA/AES  Pollution
 Control Conference in Lake Buena Vista,  Florida, in
 January  1978.  The  demonstrations confirmed  the
 feasibility of an eJectrochemical treatment approach. The
 system was applied to end of pipe discharges both before
 and after a conventional alkali chlorination system as
 well as on individual rinse tanks discharges.
  In October, 1977, following extensive discussions with
 Mr.  George  Thompson  of  EPA,   HSA  Reactors
 submitted to the Metal Finishers Foundation a proposal
 to participate in  a joint demonstration program  to
 demonstrate the technical and economic capabilities of
 their electrochemical reactor in waste treatment. MFF
 accepted the proposal  and applied to EPA for a grant of
 $155,000. to finance  a portion of the demonstration
 program. The grant was approved by EPA in June, 1978
and Varland  Metal Service Incorporated, in Cincinnati
 was designated as the metal finishing plant for the
 demonstration program.
  The  Varland plant was one of five plants selected by
 MFF. Mr. Kennedy inspected the five plants and with the
approval of EPA and  MFF selected the Varland Plant.
  The  joint  demonstration  program  was to  be
implemented in three phases. The initial part of Phase I
involved  a Plant Assessment Survey of the- Varland
operations, as shown in Figure 1.
  The remainder of Phase I was to include a follow-up to
the recommendations of the survey report and the design,
construction, and installation of a series of reactor units.
  Phase II of the program was to be composed of a six-
month operation period for the reactor systems.
  Phase HI was to allow for a four-month analysis and
evaluation of the operating data prior to submission of
the final project report.


 PLANT ASSESSMENT

 1.  Analysis of plant layout and operating
     practices
 2.  Examination of process water usage
 3.  Identification of sources of pollution
 4.  Recommendations for step-by-step
     program of changes
 5.  Basis of plan for controlling pollution
Figure 1


STRATEGY FOR POLLUTION CONTROL
  The Joint Demonstration Program involves a rational
approach  to  pollution  control   and  to  achieving
compliance  with  effluent regulations.  Rather  than
planning "end  of pipe" treatment for existing plant
operations, the strategy which Varland  is following
involves:
  I.  A thorough Plant Assessment (see Figure 1).
  2.  Implementation  of  point source recovery and
treatment wherever possible.
  3.  Installation  of  final treatment  equipment  as
necessary.
  The first two steps in this strategy will reduce both the
volume of process water and the pollution loading in this
water which must be treated  at "end of pipe." This is
expected to result in lower cost for pollution control as
well as significantly reducing the generation of sludge.

PLANT ASSESSMENT
  In August, 1978, the Phase I Plant Assessment Survey
was carried out by HSA at Varland, and a report of this
Assessment was submitted to Varland and the EPA in
October,  1978. The  Plant Assessment  included: (a)
analysis of plant physical layout, operating practices and
procedures and the recommendations of any changes
which would result in lowering the contaminant levels in
the final  plant  effluent  discharge;  (b) examination of
process water  usage  and  recommendation of ways to
reduce  the plant  usage  of process water as well  as
identification and segregation of the process waters not
requiring final treatment; (c) sampling to determine the
type, quantity and nature of the pollutants; isolation and
identification of the point sources within the plant of
these pollutants; (d)  formulation  of a  step  by step
program to effect in-plant control of pollution, and; (e)
providing a plan for compliance with local and EPA pre-
treatment guidelines.

  The  Assessment   resulted  in   more  than  forty
recommendations for  improving general  operating
                                                  17

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   PLANT ASSESSMENT
   RECOMMENDATIONS

  •  Elimination of pollution sources
  •  Reductions in process water usage
  •  Housekeeping and maintenance
  •  Attitude toward pollution control

Figure 2

practices. (See Figure 2)
  Most  of the Recommendations made by HSA have
been implemented or are planned to be implemented in
our program to control pollution. In addition, we have
applied  the concepts  discussed with HSA along with
ideas from our own staff in continuing to look for other
ways to  reduce pollution levels.
  Many of the  changes which have  been made  are
difficult  to evaluate in terms of cost and more difficult to
relate to specific benefits. For example,  longer drainage
times on some lines have slowed down production rates.
However, we feel that the longer  drainage times have
contributed to  reduced  dragout and  hence have
facilitated the reduced usage of process water and saving
of process chemicals.
  Some  specific results from the Plant Assessment can be
identified as follows:
1.  Process water usage has been reduced approximately
   45% for a c,ost saving of $15,000 per year. More
   importantly,  the basic principles will make  possible
   further water savings in the future.
2.  An annual saving of approximately another $11,000
   has been achieved through a decrease in chemical
   usage.

          VARLAND METAL SERVICE
         FINAL EFFLUENT ANALYSIS



Total Cyanide
Free Cyanide
Cadmium
Chrome
Copper
Nickel
Zinc
BEFORE PLANT
ASSESSMENT
(GRAMS)
11,973
9,191
885
9,925
2,195
5,812
27,451
AFTER PLANT
ASSESSMENT
(GRAMS)
10,513
5,356
743
5,751
1,780
4,054
22,064

DIFFERENCE
(GRAMS) (PERCENT)
—1 ,460 —1 2
—3,735 —41
-142 —16
—4,174 —42
-415 —19
-1 ,758 —30
—5,287 —20
 Daily Process
 Water Usage
 (Gallons)       205,000
Figure 3
113,000  —92,000  -45
3. The above  reductions in process water usage and
  chemical usage  will  make  a  very  significant
  contribution to reducing the pollution loadings in the
  final effluent and the costs for pollution abatement.
  (See Figure 3)
4. Another result of the implementation of the survey
  recommendations  is a  noticeable  change  in  the
  attitude of our employees - a realization that success in
  meeting goals of the pollution abatement program is
                              an absolute necessity in guaranteeing the future of
                              their jobs.
                            5. The direct costs incurred to achieve the above savings
                              consist of: (a) $5,000 capital cost of new conductivity
                              cells and timer control valves (with an estimated 5 year
                              life, for simplicity this can be considered as a $1,000
                              annual  cost);  (b)  $7,500 annually  for additional
                              maintenance  for the conductivity cells, additional
                              cleaning of tanks, etc.


                            PLANT ASSESSMENT
                            COSTS/BENEFITS
                                                               PER YEAR
                                                                  15,000
                                                                  11,060
                                                                  26,060

                                                                    1,000
                                                                    7,500
 DIRECT TANGIBLE BENEFITS
 Reduced process water usage
 Reduced chemical usage

 COST TO IMPLEMENT
 Conductivity cells
 Labour (Maintenance)


 Net annual savings
 PLUS:
 Reduced pollution control costs
Figure 4
                              See Figure 4 for Cost/Benefit Ratio.
                              Some  other  costs required  to  meet Assessment
                            Recommendations, but which are not directly connected
                            with the cost savings are; (through Dec. 31, 1979).
                                                                   8,500
                                                                  17,560
                            1. Lining Tanks, Previously Unlined                $8,530
                            i2. Titanium Anode Baskets to Replace Steel
                              Baskets.in Cyanide Plating Solutions (This
                              does not complete the replacement program)         $5,833
                            3. New tanks, to set-up the "well ordered" lines,
                              to replace some "disorganized lines"               $9,970
                              Total other costs                           $24,333
  Other highly significant information developed in the
Plant Assessment is that the amount of production in a
given process varies widely from week to week, and that,
not surprisingly,  the amount  of the particular metal
pollutant also varies  widely from  week  to  week,
practically in direct  proportion  to  the sales.  This
relationship was charted for barrel copper plating, barrel
zinc plating, and barrel cadmium plating over a 5 week
period. The sales variability (and pollution variability),
defined as maximum weekly sales divided by minimum
weekly sales, was approximately 3 to 1 for cadmium, 2 to
1 for zinc, and 6 to 1 for copper. This points out the
fallacy of depending on any 1 day effluent monitoring to
get a true  picture of a particular plant's pollution
problem; a longer study is necessary unless it is first
established that the particular plant has  very uniform
production.
  Also highly significant is the fact that regular "dumps"
of process solutions contribute greatly to the pollution
load. These  are not "dumps" of plating solutions  or
concentrated   process   solutions or  dips,  discarded
                                                18

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alkaline cleaner solutions, acid pickling solutions, etc.
These  solutions are normally bled into  the discharge
slowly so that the normal pH control keeps the effluent
within acceptable  limits. The  contribution of such
"dumps" for one typical week to the effluent was, in
mg/1:
                                 HSA REACTOR PROCESS FLOW
z«
23
Cu
0.4
Ni
0.3
Cd
0.1
Cr
8.8
   HSA  has  identified  the above problem  and  is
 presumably working to develop a solution.

 HSA REACTOR
   The main thrust of the HSA Reactor program thus far
 has  been the development of a  closed  loop  reactor
 treatment system to work with cyanide plating solutions,
 cadmium, copper, and zinc, to destroy the cyanide and
 recover the metals from the rinses immediately after the
 plating bath.
   A cadmium unit has been in operation in the plant for
 almost one  year, but has been extensively modified or
 rebuilt  from time to time, a  normal procedure for
 research and development units. A unit similar in design
 principles to what will be offered in the near future as a
 commercial unit is presently in operation in the plant,
 and that unit will be described here.

       SCHEMATIC OF HSA REACTOR SYSTEM
                           t
                      Figure 7
                      reactor handles the  cadmium from two sources.  Our
                      production is normally higher in the barrel line and the
                      dragout tank is smaller (160 gal vs 700 gal), thus this
                      arrangement sends the highest concentration of metal
                      into the reactor, allowing it to operate most efficiently.

                      PROCESS FLOW DIAGRAM FOR CADMIUM REACTOR
                              SYSTEM INSTALLATION AT VARLAND
                         BARREL LINE

                         WORKFLOW
                                        DRAGOUT
                                                 ORAGOUT
                                                         RINSE WATER
                                                     I  RINSE EFFLUENT A
                         HOIST LINE
                                                        RINSE EFFLUENT B
       PROCESS IN
      • Metals
       Metal Cyanides
       Free Cyanide
  OUTPUT
*• Low concentration
  of metals, cyanide
                   High Surface Area
                     Electrode
Figures
   Figure 5 is a schematic representation of the reactor
system. During the plating step, the metal is deposited on
the carbon fibre cathode while cyanide is electro-oxidized
and electrochlorinated at the anode. After the cathode is
sufficiently loaded, the metal is stripped into a separate
solution. The metal is recovered either by electrowinning
from  the strip solution  or by using a  strip solution
compatible with the plating bath and adding  the metal
          CADMIUM PLATING SEQUENCE
 FROM
 CLEANING'
           TO
           POST DP
Figure 6
concentrate directly  to the  bath.  Figure 6  shows,
schematically, the  work flow through the cadmium
plating bath and the Reactor Process Solution. Figure 7
shows the solution flow and Figure 8 shows the combined
work flow and process solution flow in our plant.
  The solution from the dragout tank on the cadmium
barrel line is pumped through the reactor to the dragout
tank  on the cadmium  hoist  line,  then back  to the
cadmium barrel line to close the loop. In this way, one
                                             SEWER

Figure 8
The comparatively large volume of hoist rinse solution
acts as a buffer and prevents sudden surges in cyanide or
cadmium concentrations.
  The closed loop process solution is maintained at pH
10 with NaOH and sodium chloride is maintained at 100
g/1-
                                • Sample prior to barrel addition.
                                • Sample Immediately altor barrel addition
                                              Tlmefmln.)
                            CADMIUM REMOVAL — BARREL DRAQ-OUT TANK

                      Figure 9

                        Figure  9 shows the performance of the unit  for
                      cadmium  removal.  As   each  barrel  is  rinsed,
                                                    19

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approximately 11/2 liters of solution, 27 grams Cd and
100 grams CN, is dragged into the system. In the test
shown here, the maximum cadmium dragged out from
the HSA process rinse into the running rinse was about
.18 grams  of cadmium per barrel,  thus  effectively
removing 99.4% or more of the  cadmium that would
otherwise have gone into the effluent. The reactor plated
out enough cadmium so that a low concentration would
be found in the process tank when the next barrel load
was rinsed. The D. C. power to the reactor was 600 amps
at 4 volts; flow rate was  40 liters  per minute.
  Removal  rates  for  cadmium  depend   on the
concentration of the solution entering the reactor. With a
comparatively  low  production level during  this test,
cadmium was removed at an average rate of 0.6 mg per
minute or, at 600 amps, 1 mg per  ampere minute. Other
tests,  not shown in detail here, indicated  cadmium
removal rates of 8 mg per ampere minute with an input to
the reactor of 200 to 250 mg/1 from the process solution.
In this test, cyanide was not completely removed. The
flow rate at 40 liters per minute and the current, 600 amps
at 4 volts, remained unchanged. This concentration in the
drag out tank would correspond to 99% removal of the
cadmium that would otherwise  be  discharged to the
sewer. If this removal rate is considered in relation to an
average total plant flow of 300 liters per minute,  a
production rate of 5 barrels per hour would still leave the
cadmium in the effluent from this source at less than 0.1
ppm; without the reactor, the cadmium would be 10 ppm
from this source.
                                       34mD/A-nHl>  j

                                        202 g    1
                       Time (minutes)

              REMOVAL RATE FOR CYANIDE
Figure 10
  Figure 10 shows Removal Rate for Free Cyanide under
the same conditions as shown in Figure 9 for cadmium
removal; 600 amps at 4 volts, flow of 40 liters per minute.
Removal rates shown here and confirmed by other work
indicate a removal rate of about 4 mg per ampere minute
with input to the reactor in the 200 to 600 mg/1 range. A
production  rate of 1.4 barrels per  hour would be at
equilibrium with this removal rate. If this is compared to
an average total flow of 300 liters per minute, free cyanide
in the effluent from this source would be under .03 mg/1.
Without the reactor, free cyanide would be almost 8 mg/1
at 1.4 barrels per hour.
  The reactor system used in the above tests had one
reactor module containing six reactor frames. A system
of this size under our operating conditions was able to
treat the dragout from 1.4 barrels per hour. More frames
can be added to the module and additional modules can
be added to the system according to operating conditions
and dragout levels to be treated.
  The size system required also depends on whether or
not cyanide removal is to be done entirely by the reactor
system.  As  previously  indicated,  one  could  take
advantage of significantly higher metal removal rates if
some of the cyanide were to be destroyed with chlorine or
sodium hypochlorite.
                           CADMIUM REACTOR
                             PERFORMANCE
                             OCT. 24, 1979
                       Time (hours)
Figure 11

   Figure  11 shows a different test of cadmium reactor
performance - in this graph, the cadmium removal and
the cyanide destruction are shown together. The removal
rates are essentially the same as previously stated.
   To summarize, if this reactor unit is operated with one
6  frame  reactor  module,  600 amps, 4  volts,  and a
production rate of 1.4 barrels per hour average, and total
plant effluent is 300 liters per minute, total contribution
to the  effluent from this source will be under .015 mg/1
cadmium, under .03 mg/1 free CN. Without the reactor
system in place, the comparable contributions would be
2.8 mg/1 cadmium and 7.8 mg/1 free CN. This constitutes
better  than 99  1/2%  removal of  both cyanide and
cadmium.  The   same   reactor  unit  could give
approximately the same  level of cadmium in the final
effluent at a considerably higher  production rate,  but
some portion of the cyanide would have to be destroyed
with NaOCl. Also, satisfactory performance could be
achieved at any production rate by increasing the size of
the system.
   Please  note that the above capacity figures  do  not
allow for lost reactor time for stripping,  down time for
maintenance, etc.  However, on the other side of the coin,
removal  and  destruction  capacity can  be increased
somewhat, but not proportionately, by  increasing  the
amperage from 600 to 800.
   Please also note that all cyanide analyses are for "free"
cyanide - no distillation step was used as is required in
CN-T  analysis for final effluent.
   Much of the experimental work done to date deals with
the  method of stripping and  recovering the cadmium
from the cell. The  initial method used a sulfuric acid
solution;  this worked quite well. The cadmium could be
recovered from the solution by electrowinning.
   By modifying the cell  design, it is possible to use a
different stripping scheme. This utilizes a heated cyanide
solution,  made up by using some of the plating solution
from the bath and augmenting the cyanide content. The
enriched solution will be returned at intervals to the bath
and fresh plating solution will be  made available for
                                                    20

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         CONTRIBUTION
         (ppm)
         1.2 — 2.0
         0.4 — 0.6
         0.3 — 0.5
TREATABLE BY
HSA REACTOR
 CADMIUM LEVEL IN FINAL EFFLUENT
 POINT SOURCE

 Hoist/Barrel drag-out
 Cleaners/Strips
 Dips

 HSA predicts:
                                                           PROCESS FLOW DIAGRAM FOR ZINC REACTOR
                                                               SYSTEM INSTALLATION AT VARLAND
 Cadmium in final effluent
            Without
            HSA Reactor ^-1.9 — 3.1 (ppm)

            With
            HSA Reactor -^- 0.4 — 0.6 (ppm)
Figure 12

stripping. This method also seems to work well. None of
the  enriched  solution  has  yet been  added  to the
production bath, but Hull Cell tests indicate that such
additions will cause no difficulty.
   Figure 12 is an estimate by HSA of what our cadmium
will be in the final effluent based on full time use of the
existing reactor unit  in the  plant and based  on total
cadmium production being approximately where it has
been for the last year. The 0.4 to 0.6 is, of course, well
below EPA's standard of 1.2 for daily maximum and 0.7
for the 4 day average.

   BARREL ZINC PLATING SEQUENCE
 FROM
 CLEANING
D
                                            POST
                                            DIP
Figure 13

COPPER AND ZINC UNITS
  The Reactor Unit for Copper (to be used on two
cyanide barrel copper plating operations) was delivered
on April 7,1980, and was installed and operating by April
14,  1980. No test data on  its use in our  plant is yet
available, but test results from  HSA's lab indicate it
should  operate  well. The  unit  has 4 reactor cells,
connected in parallel for solution flow and in series
electrically. Stripping of the copper from the cell will be
done with a cyanide solution. The process flow diagram
will be quite similar to that shown for zinc. The zinc unit
is scheduled for delivery and installation April 30, 1980.
Figure 13 shows the work flow through our barrel zinc
automatic plating machine. Figure 14 shows the planned
process solution flow from the various zinc sources to the
reactor.
  In both the copper and zinc systems, we will use a surge
tank to supply process solution to the reactor. This tank
has two compartments separated by an overflow dam -
total volume is 550 gallons. The zinc reactor pumps from
the  dirty side, zinc wise and cyanide wise, through the
reactor, returning the solution with decreased zinc and
                                          Figure 14
                                          cyanide  content to the clean side.  At the same time,
                                          "clean"  process solution is pumped to the dragout
                                          recovery tanks on the various zinc lines, three.of which
                                          are shown here. The loop is closed by returning "dirty"
                                          process solution back to the "dirty" side of the surge tank.
                                                      PROPOSED CLOSED-LOOP TREATMENT
                                                        SYSTEM FOR ZINC PLATING LINE
                                                                        f    \
                                          Figure 15
                                            Figure 15 shows how we plan to complete the job on
                                          our zinc plating operations by using a closed  loop
                                          treatment system for rinsing after acid pickling before
                                          plating. We plan to settle or filter out the iron in the rinse
                                          while allowing the zinc to remain in solution and be
                                          dragged  into the plating bath.
                                            Finally, Figure 16 shows a brief summary of the
                                          desirable features of the HSA Reactor System.
                                            I want to take this opportunity to thank the personnel
                                          at  HSA for their help with this paper and for  their
                                          continued work in our plant to help  us, and hopefully
                                          much of the plating industry with what appears to be a

                                                FEATURES OF HSA
                                                REACTOR SYSTEM

                                                •  Electrochemical system
                                                •  Metal recovery without
                                                    impurities
                                                •  Low operating costs
                                                •  No sludge produced
                                                •  Compact, modular units

                                          Figure 16
                                                 21

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very valuable tool in pollution control. I particularly
want to thank Ian Kennedy, Sankar Das Gupta, Bernard
Fleet, John Moore, and Graham Dickson.

REFERENCES
1.  Ian F. T. Kennedy, Electrochemical Cell for Treating
   Plating  Wastes,  AES/EPA Seminar, Buena  Vista,
   Florida, January, 1978.
2.  I. F. T.  Kennedy and S. Das Gupta, Electrochemical
   Treatment of Metal Finishing Industry Effluents in
   Chicago in June 1977. Metals Finishers Foundation
   Report, January, 1978.
3.  I. F. T. Kennedy and E. Durkin of MFF, Application
   document to  EPA for Grant, November 1977.
4.  HSA  Staff,  Regular  progress  reports  on
   demonstration project as regularly submitted to EPA,
   the Metal Finishers Foundation and to Varland Metal
   Service, Inc.
                                                 22

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      The Application  of Separation  Processes In
                     The Metal Finishing Industry
                                           Peter Crampton*
                                             ABSTRACT

                   The high cost of raw materials and pollution control provides the economic incentive to
                invest in process units which reclaim raw materials from waste streams. Evaporation, ion
                exchange, reverse osmosis, and electrodialysis are separation processes which have found
                application for raw material recovery. The range of applications of these processes, as well as the
                economic factors which limit their use are explored. Low cost plating drag-out recovery systems
                and the economics of wastewater recycle processes  are high-lighted. A ko discussed is the
                application of metal selective ion exchange resins to "polish" the effluent from a conventional
                hydroxide treatment process.
 INTRODUCTION
   Today, both economic and regulatory pressures are
 having significant impact on the cost of doing business in
 the metal finishing industry.  Raw materials and utility
 prices have increased markedly. Environmental controls
 on wastewater  discharges  and solid  waste  disposal
 impose an additional penalty for inefficient use of raw
 materials.  The economic incentive for making more
 efficient use of energy, water, and raw materials is
 significantly greater for metal finishing firms than it was
 several years ago.
   Processes which recycle raw materials  from what were
 formerly waste streams have  found increasing use. The
justification for the recovery processes are derived from
 reduced operating costs for end-of-pipe pollution control
 and  raw material savings.  These processes  have  in
 common the ability to separate specific compounds from
 a  water  solution,  yielding  a  concentrate of those
 compounds and relatively pure water. The processes
 which have enjoyed the broadest commercial success in
 this  area include  evaporation, ion exchange, reverse
 osmosis, and electrodialysis.

 EVAPORATION
  Figure 1 shows an evaporator used to concentrate rinse
water and  recycle  drag-out back to  the plating bath.
 Plating chemical recovery is the  only commercially
significant  application  of  evaporation in  the metal
finishing industry. As  shown,  the condensed vapor
overhead is of high purity and is reused for rinsing.  This
particular system  utilizes closed loop  recovery.  The
closed loop recovery system has the advantage of totally
eliminating a water discharge from  the plating process.
Such an approach,  however, requires sufficient water to
be  evaporated  and  recycled  to  satisfy  rinsing
requirements. With the high cost associated with energy,
*Peter Crampton
 CENTEC Corporation
 Fort Lauderdale, FL
high evaporative rates can quickly erode the savings
associated with raw material recovery.
  Figure 2  depicts  an evaporative recovery  system
reclaiming chemical dragout from a chromium  plating
operation. This  recovery system is an open-loop type.
The rinse rate in the recovery rinse section is set to achieve
the maximum savings in terms of operating costs. The
balance of the rinsing is be accomplished in the free rinse,
which discharges to waste treatment.
            PRODUCT FLOW
            AND DRAG-OUT
                  SUMl/F
                       FIRST Ik SECOND / THIRD
                       RINSE // RINSE U( RINSE
                       TANK U\ TANK //  TANK
                         DISTILLATE
   CONCENTRATED PLATING
                                • STEAM OR HOT WATER

                                • COOLING WATER
Fig. 1—Closed-Loop Evaporative Recovery System.
 DRAG-OUT = 1gph / 40 oz/gal
          H,CrO.
                                                                                     TO WASTE TREATMENT
                                                                                DISTILLATE
        CONCENTRATE
                                                    Fig. 2—Open-Loop Evaporative Recovery of Chromium Plating Drag-Out.
                                                 23

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  Evaporators,  which are available in  materials  of
construction  suitable  for  non-corrosive  or  highly
corrosive  applications,  have  been  demonstrated  for
recovery of chemical dragout for virtually every plating
solution in commercial use today. Despite this versatility,
reliable operation and process simplicity, the use  of
evaporators for dragout  recovery  has been limited  to
plating operations with high dragout rates, due mainly to
the considerably savings needed to justify the high cost of
installing   and  operating  conventional evaporative
recovery systems.
  Figure 3  illustrates this limitation  by comparing the
return on investment of an evaporative recovery system
to the quantity of chemical drag-out  from a chromium
plating; operation. In this  analysis, investment cost for a
  o
  a:
  x
  <
  LU

  U.
      40
      30
20
       10
                       DRAG-OUT RATE
                       (Ib H2 CrO,, /hr)

                          Basis
                          $30,000 Investment required
                          for 25 gph evaporator Energy
                          cost equals $4/10" btu
                          Operation 4000 hr/year
                          Tax rate is 48% of profit

Fig. 3—Drag-Out Recovery Investment Justification as a Fuction of Drag-
Out Rate.
                                                     capacity units were available. Referring back to the open-
                                                     loop recovery system shown in Figure 2, what would be
                                                     the  optimum recovery rinse rate in terms net operating
                                                     savings?
                                                       Net operating  savings  are defined  as  the value of
                                                     recovered  chemicals and  savings  in pollution control
                                                     costs minus the utility cost to operate the evaporator. As
                                                     shown in Figure  4, based on an energy cost of $4 per
                                                     million Btu's savings are maximized at a recovery rinse
                                                     rate of six gallons per hour. Or looking at it another way,
                                                     savings are maximized when 6 gallons of rinse water are
                                                     evaporated and recycled per gallon of dragout. At that
                                                     rinse  rate,  95 percent of the chemical  drag-out  is
                                                     recovered  and the  energy cost  associated with the
                                                     evaporative duty  is less  than 25 cents pe_r hour.
in
o
2  3
>
1/1
o
z

I  >
UJ
o.
o
                                                                          I
                                                                             I
                                                         0         5        10        15        20        25

                                                                      RECOVERY RINSE RATE (gph)


                                                                            Basis
                                                                            Net savings are defined as savings
                                                                            in recovered raw materials and pollu-
                                                                            tion control costs minus utility cost
                                                                            to operate the evaporator.
                                                                            Energy cost = $4/10* BTU

                                                    Fig. 4—Optimum Recovery Rinse Rate for Open-Loop Recovery System
                                                    Shown in Figure 2.
25  gallon  per  hour evaporator  was assumed to total
$30,000 and the unit depreciated over 10 years; energy
cost equal to $4 per million Btu's and typical labor and
maintenance costs were  used to determine operating
costs.  Savings were  based on raw material recovery,
wastewater treatment cost reductions and reductions in
solids  waste quantities. These savings totalled $1.80 per
pound of chromic acid (H2CrO4) recovered.  Using this
basis,  a reasonable return on investment is achieved for
drag-out rates above three pounds of chromic acid per
hour.  For plating baths with drag-out rates below two
pounds per hour of chromic  acid, installation of this
recovery system is not economically feasible.
   It should be pointed  out that tax credits  associated
with investments in pollution control hardware were not
included  in the  above  analysis. The  credits  would
improve  the  economics  of investments  that  would
otherwise be marginal; however, a plating operation with
low drag-out rates would still not be able to justify such a
recovery system.
   The range of  applications for evaporative recovery
systems could  be increased significantly if low cost, low
                                                       Considering the low evaporative rate needed to gain
                                                     the lion's hare of the dragout losses from this plating step,
                                                     it would seem  unnecessary to purchase  a continuous
                                                     automated evaporative recovery system. These systems
                                                     typically have minimum  size units with capacities of 25
                                                     gallons per hour and installed cost in the range of $25,000
                                                     to $35,000.
                                                       Two  low cost evaporative recovery techniques  are
                                                     available. They are direct drag-out recovery by recycle of
                                                     rinse water to the plating bath to make up  for surface
                                                     evaporation losses and the use of low cost, low capacity
                                                     batch evaporators to concentrate rinse water  for recycle.
                                                        Recycle of rinse water to the plating bath  to make up
                                                      for surface evaporation losses (Figure 5) is a  form of
                                                      evaporative recovery that has the advantage of minimal
                                                      investment requirements.  For high  temperature baths
                                                      operated in the 150° F temperature range, sufficient
                                                      evaporation will occur to reclaim the bulk of the dragout.
                                                      Use of air agitation in the plating tank will increase the
                                                      surface evaporation rate.  Make-up to the bath can be
                                                      done manually or automated as shown in Figure 5. In the
                                                      Figure, level sensors control make-up to the bath and
                                                       24

-------
      SURFACE EVAPORATION
                                WATER SUPPLY
          PLATING BATH
             — LEVEL CONTROLLER
 Fig. 5— Automatic Rinse and Recycle Recovery System.

 additions of fresh rinse water.
   For baths where the surface evaporation rate is not
 sufficient to effectively utilize rinse and recycle recovery,
 a simple batch evaporator, or still, can be used to enhance
 recovery.
   Stills of the sort recommended for this application can
 be constructed in the shop or purchased. Figure 6 shows a
 home made unit used to augment surface evaporation
 from a nickel plating solution. Steam supplied to the coil
 heats the solution, which humidifies air bubbled through
 the solution.  A convenient recovery procedure using a
 batch evaporator of this type is presented in Figure 7.
                        HUMIDIFIED
                           AIR
SUPPLY ' 	
NTRATE
NG BATH
|
M
.


.11

(c
a
C<
°o°o o°o "o0*0 o
*


D
< STEAM

                       AIR SPARGER
Fig. 6—Batch Atmospheric Evaporator.
                              MAKE-UP WATER
•*•
cr



P
PLATING
BATH


-p c



-i^^Jq-
STILL
RINSE A

BATCH
EVAPORATOR

p




                                 STILt
                                RINSE  B
FREE
RINSE
       TRANSFER SEQUENCE
       1) TRANSFER EVAPORATOR CONCENTRATION TO PLATING BATH
       2) TRANSFER STILL RINSE A TO EVAPORATOR
       3) TRANSFER STILL RINSE B TO STILL RINSE A
       4) ADD FRESH WATER TO STILL RINSE B
Fig. 7—Batch Recovery System Daily Sequence.

   For baths with  no surface evaporation losses, the
evaporator can be fed a blend of rinse water and plating
solution to provide  the volume in  the plating bath for
recycle of the concentrate.
   Figure 8 is a schematic of an atmospheric concentrator
which sells commercially for approximately $6000. The
unit  has  an evaporative rate between five to ten gph.
Although this and the unit shown in Figure 6 may not be
                                                            HEAT
                                                            EXCHANGER-
                                                                                    EXHAUST
                                                                                     A
                                                                                                  PACKED COLUMN

                                                                                                  SUCTION PUMP
                                                                                                          BLOWER
                                            SUMP
              Fig. 8—Batch Atmospheric Evaporator.

              energy efficient, the fact that they consume only small
              amounts of energy makes insignificant the cost penalty
              associated with the inefficiency.
                In summary, the use of evaporation is still the most
              reliable,  versatile,  and  easily  understood  separation
              process for recovery of dragout. Cost effective utilization
              of evaporative recovery can be realized in many cases by
              direct drag-out recovery to make up for plating bath
              surface  evaporation or where  necessary, augmenting
              surface evaporation with low cost, low capacity batch
              evaporators.

              ION EXCHANGE
                Ion exchange is a versatile separation process which
              has found application within the metal finishing industry
              for:
                • Concentration of  plating  chemical  dragout  for
                  recycle to plating bath  and  rinse water reuse
                • End-of-pipe wastewater treatment
                • Mixed wastewater deionization and water reuse
                • Polishing after conventional wastewater treatment
                  to reduce the concentration of dissolved metals
                • Purification of spent acids
                • Water supply  deionization
                                                              LOADING
                                                              DILUTE
                                                             SOLUTION
                 H+FORM
                 CATION
                 RESIN
                 COLUMN
               V
              DILUTE H2S04
REGENERATION
CONCENTRATED!
     CuSoi,
   SOLUTION
                                                                                                   A
      EX-
   HAUSTED
    CATION
     RESIN
    COLUMN
   10IH2SOtt
  SOLUTION
               SOLUTION
             Fig. 9—Ion Exchange Concentration of Copper Sulfate Solution.
                                                       25

-------
  Ion exchange is a reversible process where a solution is
passed through a bed of resin particles which exchange
ions attached to the solid  resin  matrix for  similarly
charged ions in the solution. In Figure 9, the exchange is
between  copper  ions  in  solution for  hydrogen  ions
attached to the cation resin. When the resin's exchange
capacity has been exhausted, the bed is regenerated with
a suitable solution, in this case sulfuric acid, which elutes
the collected copper ions and returns the resin bed to its
original form. The copper in the feed solution has not
been changed chemically, but it has been concentrated
into a much smaller volume.
  The early ion exchange systems  were of the fixed bed
variety. These systems were often  made continuous by
duplexing  of  the  columns  to  allow  for  sustained
operation during regeneration. The significant cost and
complexity of such fixed-bed systems minimized  their
application for recovery of plating chemicals from  rinse
solutions.
  The development of  the Reciprocating Flow  Ion
Exchanger enhanced the potential application of ion
T
Cation

Exhaust
(to waste
treatment)
Product
4
Cation
t





Rinse
Water


f 1 '
Anion Cation
•
. -
Purified
water
Exhaust
(to waste

treatment)
Anion Cation
i i
i
_^LjT

NaOH
exchange for plating drag-out recovery by providing a
lower cost, compact, automated ion exchange recovery
system. This unit was especially developed for purifying
the bleed stream of a large volume solution, such as the
overflow  from   an electroplater's rinse  tank.  The
operating principal  of a reciprocating flow unit for
chromic acid recovery is presented in Figure 10. The unit
operates on the principle that for the short period it goes
off-stream  for  regeneration,   the  build-up  of
contaminants  in the  rinse  system  is  negligible. The
advantages of this unit over fixed bed  systems for such
applications include:
  • Reduced equipment cost (due primarily to the small
    resin volume required)
  • The unit automatically regenerates itself minimizing
    labor requirements
  • Compact  size
  Reciprocating flow units are currently being utilized
for dragout recovery from chromium, copper, and nickel
plating rinses, for purification of spent process acids and
for mixed wastewater deionization.
                                                              ON STREAM  (LOADING)

                                                              Rinse water is  pumped  from the chromium
                                                              plating  rinse tanks through the prefilter to
                                                              remove  any solids,  then through the first
                                                              cation bed where cationic contaminants
                                                              (e.g., Fe+3, Cr+3) are removed by  the resin.
                                                              The rinse water then passes through the
                                                              anion bed where the chromate ions are
                                                              removed.   The purified rinse  is returned  to the
                                                              rinse system.  While the unit  is on stream,  the
                                                              second cation bed  is regenerated.
                                                              REGENERATION

                                                              After a preset period of time,  the unit goes
                                                              off stream.   The first cation bed is  regenerated
                                                              with sulfuric acid and washed  with water.
                                                              The anion bed is regenerated with sodium
                                                              hydroxide and the  effluent is passed through
                                                              the second cation bed;  the concentrated
                                                              chromic acid solution resulting is returned to
                                                              the plating  tank.
        Water
       _L
        Cation


\

Anion

Exhaust
(to waste
treatment)
Cation
Concentrated f
NaOH I
I | Water
^^^A^^riS^fJ

J
    WASHING

    The three beds are then washed with water,
    as the product from the anion bed contains
    the excess caustic used in the regeneration
    step, it  is mixed  with concentrated  NaOH
    and used in  the next  regeneration cycle.
    The unit then  goes back on  stream.
 Fig. 10—Reciprocating Flow Ion Exchanger Operating Cycle.
                                                      26

-------
   The  use of  ion exchange for  mixed  wastewater
 deionization and reuse is an application which could see
 considerably more use in the future.
   Figure 11 shows a commercially operated wastewater
 deionization treatment system which has been operated
 since 1975. The system was designed to process lOOgpm
 of  plating wastewater containing copper,  nickel,  and
 trivalent and hexavalent chromium. The wastewater also
 contains trace amounts of cyanide.
 TO CLAR1FIER
TYT Y
       WATER TO PLATING

 © - CONDUCTIVITY PROBE
Fig. 11—Ion Exchange Wastewater Reuse System.

The system features:
   •  Activated carbon prefilters to trap oil, free chlorine
   and suspended  solids which might foul the resin bed
   •  A conductivity probe to monitor the purity of the
   treated  water. When the dissolved solids content of
   the treated  water reaches a certain  concentration,
   the flow is diverted  to the off-stream columns and
   the  spent  columns  are regenerated.  A  column
   usually  operates for three days prior to regeneration.
   •  A  batch  treatment  tank  is used  to  treat the
   regenerant solutions. The batch treatment sequence
   employs successive  steps  for  cyanide oxidation,
   chromium reduction, and metal precipitation.  The
   treated  solution  is  processed  in  the flocculation/
   clarification  sequence  used  to process the  plants
   non-plating wastestreams.
   •  A conductivity probe is installed on the treatment
   system   feed.   If  the wastewater  is   grossly
   contaminated,  the flow is  diverted  to the  batch
   treatment tank.  Treatment  of  wastes with high
   concentration of contaminants  by ion exchange is
   economically unfavorable.
   This system processes approximately  300,000 gallons
of water per cycle. Each cycle produces  approximately
400  gallons of acid regenerant, 600 gallons  of caustic
regenerant   and 6000  gallons  of wash water; these
solutions are discharged  to the batch treatment tank.
Deionized  process water is used for wash water and its
discharge acts as a purge to control the build up of any
contaminants  not removed by  the  recycle  system.
Treatment  of the pollutants is not eliminated; however,
the chemical destruction system is reduced to a single
batch tank. The plant reports that the cost to operate the
ion exchange system is  $60,000 per year.
  The use of this type treatment for selected rinse waters
can be justified  by savings in water and sewer fees and
reduction  of the  investment  required  for  pollution
control hardware.  Figure 12 compares the chemical cost
of a wastewater deionization and reuse system to the
chemical cost associated with the conventional treatment
approach. The chemical cost for the ion exchange process
includes  regeneration  chemicals   plus   the   cost to
                                                                  60
                            a  5»
                                                                                                         500.
         0        100     200      300      400
                    METAL CONC. (ppm CuSO,,)
Fig.  12—Treatment Chemical  Cost Comparison: W*ttewa1*r
Delonization/Reuse Versus Conventional Waste Treatment.

precipitate the copper from the regenerants and assumes
recycle of 90 percent of the incoming wastewater.  The
chemical consumption  for the conventional treatment
approach, includes:
  •  Lime to precipitate the copper
  •  Lime to raise the water pH from neutral to 9.0
  •  Lime to react with naturally occuring alkalinity in
   the water supply
  •  Polyelectrolyte  for flocculating  the  wastewater
   solids.
  As shown,  for treatment  consisting solely of pH
adjustment  and  flocculation  to  separate  metals as
insoluble hydroxides, ion exchange compares favorably
only  for treating very  dilute solutions. Treatment of
wastewater typical of the metal finishing industry is less
costly by conventional chemical processes.
                       TREATMENT
                         COST
                       ($/1000 Gal.)
                                                  _L
                                                     Basis
                                                     Cost Comparison Assuming
                                                     Water Fee of 50C/1000 Gal.
                                                          J_
                                           100      200      300      1100      500

                                               METAL CONC. (ppm CuSo^l

                       Fig.  13—Treatment  Chemical  and  Water Use  Cost Comparison:
                       Wastewater Deionization/Reuse Versus Conventional Waste Treatment.
                         Figure 13 presents a similar analysis, but includes a
                      water use fee equal to fifty cents per thousand gallons of
                      water consumed. In this case, an ion exchange system
                      achieving 90 percent water reuse is more economical for
                      treatment  of  waste  streams  up  to  a  metal  salt
                      concentration of 250 ppm. With the water recycle credit,
                      deionization of selected rinse waters compares favorably
                      with  a  chemical  destruct  system  For  wastewaters
                      containing polutants requiring more extensive treatment,
                      such  as  those containing hexavalent chromium, ion
                      exchange compares favorably up to higher concentration
                      levels.  Treatment  of spent  concentrates  or  grossly
                      contaminates wastes should  still be  accomplished by
                      conventional treatment techniques.
                         A wastewate deionization reuse system is particulary
                      attractive for plants which have access to a centralized
                      treatment  facility  for  industrial  wastes.  The  central
                                                      27

-------
WASTEWATER

CONVENTIONAL
TREATMENT
SYSTEM



SAND
FILTER
1
       REGENERATION
 SPENT
CATION
COLUMN
SODIUM
 FORM
CATION
COLUMN
                                           WASTEWATER
                                            DISCHARGE
Fig. 14—ion Exchange Polishing After Conventional Treatment.


concentrates and spent processing solutions, eliminating
the need for any chemical destruction system.
  Another application of ion  exchange which  could
receive increased attention for plants unable to achieve
required metal concentration discharge limitations is ion
exchange  polishing  after  an  existing  conventional
treatment  system. (Figure  14)  In some  areas, plants
discharging wastewater directly into receiving waters are
being required to achieve effluent metal concentrations in
the 0.1 to  0.2 part per million range:
  It  is unlikely that  these concentration  levels can be
consistently  achieved  with   a  metal  hydroxide
precip it at ion/clarification/filtration  treatment
sequence.  An  ion  exchange   polishing,  using  fairly
recently developed  chelated cation exchange  resins,
offers a relatively inexpensive means of achieving effluent
metal concentrations in the tenth of a part per million
range. These chelated resins have a high  selectivity for
heavy   metal  cations  in  the  presence  of  high
concentrations of similarly charged sodium, calcium, or
magnesium ions. As an example, augmenting a 30 gpm
treatment  system with an  ion exchange polishing system
consisting of two  columns, each containing seven cubic
feet of cation resin, would cost  approximately $20,000.
Based on  an inlet metal concentration of five parts per
million  and a conservative estimate of resin capacity,
each  column  could  process   approximately  330,000
gallons  of wastewater prior to regeneration.
  Assuming continuous operation 24 hours per day, this
corresponds   to  a  regeneration  frequency  of
approximately  one   column   every  8   days.  Each
regeneration would  consume  50  gallons  of  10%
hydrochloric acid and 60 gallons of 10% caustic soda.
These solutions would be treated in the conventional
treatment   system.  Chemical   cost  for   regeneration
chemicals  would  amount to only $17.00 per cycle, or
approximately $2.00  per  day.

MEMBRANE  PROCESSES
  Membrane processes utilized in the plating industry
include  reverse osmosis and electrodialysis. Beyond the
similarity  of using membranes to achieve the separation
of water  from dissolved solids,  both  processes are
continuous,  come in  compact modular units, and have
low  operating  costs over  a broad  range of loading
conditions.
  Both processes are being applied for drag-out recovery
from plating rinse waters. Pre-engineered packaged units
cost  $25,000  to  $35,000 installed.  As such,  their
application is limited to baths with high drag-out rates. A
significant  saving in  replacement  chemicals and
treatment costs is needed to justify the initial investment.
  Reverse  osmosis (Figure 15) is a pressure driven
membrane separation process where water molecules are
preferentially forced through the microscopic pores of a
serni-parmeable membrane. The salt molecules dissolved
in the water  solution,  due to  their larger  size, are
restricted from passage through the membrane pores.
                                         HIGH-PRESSURE
                                            PUMP
                                                                                    SEMI PERMEABLE
                                                                                      / MEMBRANE
                                                          CONCENTRATE
                                       Fig. 15—Simplified Reverse Osmosis scnemanc.
                                         Reverse  osmosis  units  using  a  cellulose  acetate
                                       membrane have been successfully applied to concentrate
                                       the dragout from plating solutions; both the concentrate
                                       and the purified water are recycled. Cellulose acetate
                                       membranes are not stable over a broad pH range and the
                                       primary application is for Watts Nickel Plating Baths,
                                       which  provide  a mild  chemical  environment.  Other
                                       dragout recovery applications include acid copper, acid
                                       zinc, and chromic acid baths, however,  pretreatment to
                                       assure that the membranes are not exposed to low pH
                                       conditions is needed for  these applications.
                                         Reverse  osmosis is also  limited in  the degree  of
                                       concentration  it  can  achieve.  Consequently,  for
                                       applications where plating baths have minimum surface
                                       evaporation, suplemental evaporation of the concentrate
                                       may be required prior to its recycle.
                                         Another application of reverse  osmosis which has
                                       received  recent   attention  is  mixed  wastewater
                                       purification with recycle of the permeate and treatment
                                       of the concentrate. The application is attractive because
                                       of the continuous operation and  low operating cost
                                       characteristics of RO units. However, it is questionable
                                       whether RO membrane systems are sufficiently reliable
                                       or durable to operate under the  variable conditions
                                       characteristic  of mixed wastewaters. Potential problems
                                       include  membrane fouling due to contaminants in the
                                       feed stream or precipitation of salts in the concentrate,
                                       membrane  deterioration  due  to  the  chemical
                                       environment,  and high levels of dissolved solids in the
                                       permeate.  As  newer,   more  chemically  durable
                                       membranes  are  developed  and  field proven,  this
                                       application may see greater implementation.
                                         In electrodialysis, contaminated rinse water is passed
                                       through a network of alternately spaced anion permeable
                                       and  cation permeable  membranes  (Figure  16). An
                                       electrical potential is applied across the membranes to
                                       provide the driving force for the ion passage through the
                                       membranes. This configuration creates channels which
                                       are alternately concentrated or diluted of ions. The major
                                       difference compared to RO is that, like ion exchange, the
                                                     28

-------
 C-CATION-SELECTIVE MEMBRANE
 A-ANION-SELECTIVE MEMBRANE
 M+-CATIONS
 X—ANIONS
    PURIFIED RINSE
   WATER TO RINSE •*"
       TANKS
      CATHODE (_)
                               CONCENTRATED PLATING
                             DRAG-OUT (TO PLATING BATH)
T	t

                    t   t  t  t  t  t
                   x*  j             I  U	 CONTAMINATED
            DILUTING '    '       '      '  '       RINSE
            CIRCUIT    CONCENTRATING CIRCUIT     FEED
Fig. 16—Electrodialysis Flow Schematic.
separation of water from salt is achieved by selective
removal of the salt, not concentration by driving off the
water. Unlike ion exchange, the units are continuous and
the only operating cost is for electricity, about 7 kW.
  The membranes used in the electrodialysis stack are
essentially thin sheets of the same polymeric network
used to make ion exchange resins. A cation permeable
membrane will have negatively charged, fixed ion sites
which will attract the positively charged cations into the
membrane, but repel  negatively charged anions.  The
cations will continue through the membrane due to the
electrical potential that is applied.
  Like  ion  exchange  resins,   the  electrodialysis
membranes are durable to most chemical environments.
They are membranes, however, and are subject to fouling
if the potential exists.  Current applications include the
recovery of dragout from rinses  after nickel, acid zinc,
zinc cyanide, and chromium plating processes.
                                                      29

-------
      Does  Recovery Reduce Treatment  Needs?
                                             F. A. Steward*
INTRODUCTION
  The answer to the question posed by the title is a
resounding YES. However, the author is strongly of the
opinion  that companies purchasing treatment facilities
should look  for the  reduction only in operating costs,
treatment chemicals, labor, and sludge disposal.
  There seems to be a wide spread impression that less
waste treatment capacity need be provided if recovery
equipment is to be installed.  We strongly recommend
that this approach not be taken.  The treatment system
should be designed  with adequate capacity to  handle
upsets,  recovery  system downtime,  accidents,  etc.
Payback on the recovery equipment should come only in
the operating savings.
  This paper will  present data from an actual case to
illustrate the kind of problems which pan arise.
  By way of background, our company supplied a waste
treatment system for a  new plating facility  that made
extensive use of recovery technology. After installation,
it was found to be impossible to consistently maintain the
required effluent quality. Investigation showed that the
problem was almost entirely a result of inability to handle
the sludge quantities being generated. Modification of
the plant to increase sludge handling capacity  is  now
underway.
  For a variety of reasons, the company that installed the
new facility has asked to remain anonymous. In spite of
the fact that this detracts from the authenticity of the case
history, we felt the insight gained through experience at
this plant would be of interest and value to the industry.

THE PRODUCTION PLANT
  The new electroplating facility was ideally suited to
materials recovery. It was a brand  new plant designed
with a single, automated, high-production plating line to
put a decorative chromium finish on plastic pieces. The
plant  is  clean, modern, and has a  very steady  rate of
production  averaging about  1,500 ft2 per  hour.  The
process steps in the plating line are as follows:
      Plastic Etch
      Electroless Nickel
      Nickel Strike
      Copper Plate
      Semi-bright Nickel
      Bright Nickel/Dur Ni Nickel
      Chromium Plate
      Chromium Strip
      Nickel Strip

          IN - RECOVERED = WASTE
*F. A. Steward, Vice President, Engineering & Sales
 ERC/Lancy, Division of Dart
 Environment and Services Company
 525 West New Castle Street, Zelienople, PA 16063
  With the exception of the strippers, copper plate and
electroless nickel,  each process bath was followed by
recovery rinses connected to recovery units. Given the
design  flow  through the recovery  rinses, and  using
classical rinsing calculations, approximately 99% of the
dragout from  each major  process  is  available for
recovery. Overflow from the chrome recovery rinses goes
to separate evaporators. The etch recovery loop includes
a cation exchanger for removal of trivalent chrome. The
nickel recovery rinses  are tied into two separate ion
exchange systems.

DESIGN  BASIS
Waste Loads
  The sales engineer on the job assumed that 95% of the
dragout would  be recovered from each of those processes
followed by recovery rinses. The following table lists the
total waste loads calculated to be present if no recovery
were practiced, together with those expected to reach the
treatment  system.
     Cr
     Ni
     Cu
           No-Recovery

           52.0 Ib/hr
           14.4
           3.8
            70.2 Ib/hr
Expected Load

3.4 Ib/hr
2.6
3.8
                               9.8 Ib/hr
  The figures in this table, as well as those throughout the
report, are based on quantities of dry sludge which would
be  generated. They  are  calculated by taking the
hydroxides of each of the metals. The  No-Recovery
figures were calculated by using estimates of the dragout
to be expected for the production rate on the machine.
The figures under Expected Load include the dragout
from the two strippers, electroless nickel, and the copper
plating bath as well as 5% of the anticipated dragout from
the recoverable processes.
  It was agreed during the initial  sales discussions that
extra waste resulting from downtime on the recovery
equipment  would be hauled away be a contract waste
hauling company.

Press Capacity
  The filter press included in the original design had the
following capacity:
2.5 ft3 /cycle
              3Q% Dry Solids * 80 lb/ft3  =  30 Ib/hr
               2 hr/ cycle
   Thus,  the   sludge  dewatering  equipment  had
 approximately  three times the capacity theoretically
 assumed to be needed. This was felt adequate to provide
                                                   30

-------
for inert solids and extra loading due to minor upsets. As
mentioned earlier, operation after start-up indicated that
the filter press was completely inadequate for the loads
reaching the treatment system. As a result, a series of field
investigations was conducted.

 FIELD INVESTIGATIONS
   On  October 16,  1978, engineers  from our company
 visited the plant and spent a full day investigating the
 sources of the extra load.  Numerous leaks, drips, and
 spills were observed as can be expected during start-up of
 a major production operation. Approximately six weeks
 later, a second visit and two days of investigation by two
 engineers indicated  that many of  the  initial start-up
 problems had  been resolved, but  that  the treatment
 system was still overloaded  with sludge.   Samples
 collected during this visit indicated that overflows from
 the rinses on the plating line could  not account for the
 quantities of sludge being experienced.
   After several meetings  and discussions, extra  filter
 plates  were ordered  for the  press to  approximately
double its capacity.  In  early January,  a  run of the
treatment system was attempted  for four  consecutive
days of twenty-four hour operation.  During this period,
an attempt was made at a material  balance around the
entire plant. While we have long realized that an accurate
material balance in a plating operation is extremely
difficult, we were particularly frustrated in this case by an
inability to get samples from various   points in the
recovery loops. As one example, tanks  in  these loops
would  overfill and spill onto the floor. It was impossible
to  accurately  estimate  the  volume  lost,  and  the
concentration  was  variable  from  time to  time.  In
addition,  several of the waste lines from the various
recovery units were manifolded together so as to make
separate   sampling  impossible   without   piping
modifications.
  Based on the results of the study in January, it was
agreed to run a performance demonstration during which
the  recovery  units  would  be operated  under  the
supervision of factory representatives from the suppliers
and the treatment system would be operated under our
supervision. This demonstration was to run four days,
twenty-four hours per day. The ultimate conclusion was
that  the expanded filter  press  was only  marginally
capable of handling the waste load under such idealized
conditions.
Waste Sources
  The sources of un-anticipated load on the treatment
system which were  identified  during the four  field
investigations deserve mention, since they illustrate the
types of problems common in metal finishing plants.
     Hoses in rinse tanks
     Downtime
     Rinse tank dumps
     Losses of recovery liquors
     Wastes from recovery units
  As is common in  many production operations, and
almost inevitable during start-up, the plating operators
would use hoses to  supplement the flow  of water to
various rinse tanks to keep them "clean." In some cases,
this extra flow was causing an overflow over the rim of
the tanks onto the floor. In other cases it was overloading
the  recovery systems  causing  losses  from them as
discussed later.
   Over the period of time our engineers spent in the
 plant, there was never any time that all of the recovery
 units  were  operating.  During  the  final  four  day
 demonstration, downtime was very minor. However, it is
 unlikely that such close attention and supervision can be
 provided  in  a typical operating  plant. Designers and
 purchasers of major industrial processes are keenly aware
 of the impact of downtime.  It is  a factor  which is
 recognized and anticipated. Such must also be the case
 with recovery systems in metal finishing operations.
   As a carry-over from operating practices prior to the
 use of recovery  and  waste  treatment equipment,  the
 operators in this plant  would periodically dump  the
 contents of the rinse tanks to allow them to remove parts
 which dropped off  racks. Obviously, such a practice
 places  extra  hydraulic   and  chemical  load  on  the
 treatment system simply as a result of the normal free-
 flowing rinses. However, dumps of the recovery rinses are
 particularly troublesome. The first recovery rinse after
 the chromium processes is a highly concentrated liquor.
 The periodic dump .represented a loss equivalent to many
 hours of production.
   Those same concentrated liquors mentioned above can
 be easily  lost from  the loop en route to the recovery
 equipment.   Even  more significant is  the  loss   of
 concentrated liquor  after it has been processed  by the
 recovery equipment.  In either case, the loss can occur as a
 result of tank overflows due to misadjustment of timers,
 failure of level controls or pumps, or due to the operator
 increasing the flow at the recovery tanks on the plating
 line. There were actually cases when the loads reaching
 the waste treatment system were higher than would have
 been experienced if there were no recovery units at all!
   Each of the recovery systems includes a "waste" line
 and a purchaser should  pay careful attention  to the
 quantities which will  leave by this route under ideal
 conditions and also to the variables which can affect that
 quantity.  Quite often the tuning adjustments can be
 critical and require close attention from the laboratory
 and operating people. To  be used to  best  effect, a
 recovery loop  should be regularly analyzed  by the
 laboratory as though it were  another process.
MATERIAL BALANCE
  Anyone  who  has attempted to strike a reasonable
balance  around  various  parts  of a  metal  finishing
operation will appreciate the difficulty. The primary
equation needing to be solved in this particular case can
be stated as:
  We found it impossible to get a reasonable fix on the
quantities being recovered due to the numerous variables
involved.  Le'vels  and  concentrations  were  changing
constantly in tanks. Units were operating or  down on
varying schedules. Tanks would periodically  overflow
onto the floor.
  A reasonable estimate on the IN factor is  available
from calculations based on dragout rates, and  these can
be confirmed by analytical checks on the flow of water
going to recovery and/or treatment.
  The third factor, WASTE, can be judged by collecting
the filter  case  generated  and analyzing  a composite
sample.
                                                    31

-------
IN
  Two different spot checks were made to confirm the
assumptions used  to  calculate dragout in the initial
design work. In the first, the recovery rinse after the etch
bath was sampled for analysis and the flow rate checked
carefully. The analysis showed 26.4 g/1 CrOs which, at a
flow  of  120 gal/hr,  corresponds  to 26.4  Ib/hr  of
chromium hydroxide.  This corresponds to 30 Ib/hr as
calculated from the assumed dragout at 7.5 gal/hr from
the etch bath alone.
  A second spot check is based on analysis of the treated
wastewater flow as it enters the clarifier. The suspended
solids concentration was 938 mg/1 at 145 gal/min on the
flow meter and  1,050 mg/1 at 140 gal/min. These values
correspond to total dry sludge readings of 68 and 73 Ib/hr
respectively. These readings were taken at a time when all
recovery  systems were out of operation. These figures
correspond to the calculated value mentioned earlier of
70.2 Ib/hr total sludge generation.
  In  both cases  the  agreement  is reasonably good,
supporting the  assumptions used  for  the  dragout
calculations. Better correlation cannot be expected given
the variables in a metal finishing operation and waste
treatment system.

OUT
  During the last four day demonstration run, the filter
cake collected averaged  49 Ib/hr (dry). Collection of a
true composite from a mass of filter cakes is a difficult
chore, and was  not attempted. Nevertheless, an average
of the analyses  of several filter cakes taken  at different
times during the run is as follows:

      Cr(OH)3  - 29.9%  - 14.6 Ib/hr
      Ni(OH)2- 12.1%-5.9 Ib/hr

  Since production was virtually constant during the
entire four day run, the  recovery systems were  kept
operating at close to 100%, and under good control, and
rinse dumps were avoided, the composition  of the filter
cakes could be expected  to be  reasonably  constant.
Therefore,  within the level  of accuracy which can  be
expected from such a material balance, these figures are
felt to be representative.

RECOVERED
  The rate of chromium recovery can  be expressed as
follows:
                                Similarly, the recovery rate for nickel can be expressed
          52 - 14.6
          52- 12
37.4
 40
=  93.5%
  The  figure  of 12  Ib/hr  corresponds to the  "un-
recoverable" chrome which includes dragout from the
stripper and the trivalent chrome in the dragout from the
etch bath.
                                       14.4- 5.9
                                       14.4 - 2.0
                                            =     m    =  68-5%
                                In  this case, the un-recoverable nickel includes  the
                             dragout from the nickel stripper and the electroless nickel
                             bath.
                                It is important to note that the indicated recovery rates
                             were  maintained during the four day demonstration at
                             which time the  recovery units were under the careful
                             attention of factory representatives. These rates would be
                             decreased in a normal production  plant by the various
                             factors  discussed earlier under Waste Sources.
CONCLUSIONS AND RECOMMENDATIONS
Forecast Versus Reality
  This paper illustrates numerous ways in which the
actual results realized with recovery equipment can vary
from the original expectations. While it is true that most
of these can be covered by a shrewd evaluation of what
can be  expected,  it is also true  that there are many
variables in other production plants which have not been
covered in this case history.

Housekeeping Burden
  It is clearly false economy to invest in recovery facilities
unless careful housekeeping procedures are instituted.
Spills, dumps, and overflows can lose as much as the
recovery equipment is attempting  to reclaim.

Manpower Needs
  Recovery  equipment  will  not  operate  without
attention. It is an axiom in process  design that each piece
of moving equipment needs men to maintain it and men
to operate and adjust it. We have seen literally dozens of
cases where sophisticated recovery equipment sits  idle
because  the  plant doesn't "have  time"  to  keep  it
operating. When doing your initial payback calculations,
be sure to include realistic estimates of the time required
for operators to tweak the controls, maintenance people
to keep everything running, and  laboratory people to
periodically analyze the recovery rinses and  concentrate
streams.

Waste Treatment  System Capacity
  We strongly recommend that a waste treatment system
be  installed  with  adequate capacity  to  handle all
anticipated loads from the metal finishing operation.
This allows the  plant to continue producing  during
downtime on recovery equipment and also gives the extra
capacity  to handle the accidents and upsets which are
inevitable in a complex processing operation.
                                                     32

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           Regeneration  of Waste Chromic  Acid
                          Etching Solutions  in  an
                  Industrial-Scale Research  Unit
                          L. C. George, D. M. Soboroff and A. A. Cochran*
                                             ABSTRACT

                   Substantial amounts of chromium are lost in various surface-finishing operations
               and pollution problems are created when spent solutions containing hexavalent
               chromium and sulfuric acid are discarded. Laboratory research has shown that these
               spent etching solutions can be regenerated in a diaphragm cell. When the spent
               solution is placed in the anode chamber, most of the Cr3*, produced during etching
               operations,  is oxidized  to Cr6*. Impurity metals  dissolved during the etching
               operation are transferred to the catholyte.  When waste  brass etchants are treated,
               about one-third of the copper and zinc is removed.  The  energy consumption is less
               than 9 kwhr/kg of sodium dichromate regenerated. Similar results are obtained with
               spent printed-circuit-board etchants and rinse waters from plastic etching operations.
               An industrial-scale research unit capable of oxidizing up to 0.5 kg/hr of trivalent
               chromium has been operated to demonstrate the viability of the recycling techniques.
               Regenerated brass etchants evaluated by two companies equaled or exceeded the
               performance of fresh etchants.
 INTRODUCTION
   The mission of the Bureau of Mines is to ensure the
 continued viability of the domestic minerals and minerals
 economy and the maintenance of an adequate mineral
 base, so that the Nation's economic, social, strategic, and
 environmental needs can be better served. Part of the
 work done in support of this mission has as its goal
 secondary resource  recovery and effecting pollution
 abatement. In accordance with these  activities, the
 objective of this investigation has been  to develop  a
 method for regenerating and recycling spent chromium-
 bearing process liquors that are currently discarded as
 wastes.
   Solutions containing Cr6+ and sulfuric acid are used in
 brass  finishing,  printed  circuit  board  etching,
 preparation of plastic for plating, anodizing, and various
 other surface treatments. As the solutions are used, Cr6+
 is reduced to Cr3+, the dissolved solids content increases,
 and the acid concentration decreases. The action of these
 solutions on a copper substrate can be represented by the
 following reaction:
  Cr2O7
+ 3 Cu + 14 H+ - 2 Cr3+ + 3 Cu2+ + 7 H2O
A spent  printed  circuit etchant, for  example, would
contain considerable amounts of Cu2+,  Cr3+, and Cr6+. A
spent brass etchant would contain zinc in addition to
*L. C. George and A. A. Cochran, Research chemists
 Rolla Research Center, Bureau of Mines, U.S.
 Department of the Interior, Rolla, Missouri.
 D. M. Soboroff, Research chemist
 Office of Water Research and Technology
 U.S. Department of the Interior, Washington, D.C.
these components. Actual plant practice involves adding
sodium dichromate to the process tank to replenish the
Cr6+ that has been reduced and to make up losses from
drag-out. The entire tank is dumped when the etchant no
longer performs properly despite additions. The decision
to dump or add reagents is often made on the basis of the
appearance  of the  part being etched and not on a
chemical analysis of the etchant. Technology for ultimate
disposal of these wastes usually involves the reduction of
the remaining Cr6+ to Cr3+ followed by base addition to
precipitate chromium and other metallic hydroxides. The
resulting sludges are then used for landfill.
  The disposal of these solutions in this manner wastes
valuable resources  and is cause for environmental
concern. All U.S. primary chromium production is from
imported ores. More than 2.7 X 107 kg  of chromium are
used annually for metal surface treatment and corrosion
control measures (4). The minimal recovery technology
practiced by  the metal finishing industry results in the
discarding of valuable secondary resources. In addition,
chromium has long been recognized as a major pollution
problem and its disposal is regulated  by the EPA  (9).
Landfill areas suitable for metal hydroxide sludges are
becoming scarce, and collection, treatment, and disposal
by waste contractors is expensive (3).
  For these reasons, it is desirable to develop a method
that would effect economical, in-plant recycling of spent
chromic acid-sulfuric  acid etchants.  Recycling such
etchants would result in a major reduction of chromium-
containing effluents, thus reducing the costs of waste
treatment and disposal. Further, recycling these etchants
would conserve chromium, thus reducing process costs
by reducing chromium purchases.
  Several electrolysis methods have been proposed for
                                                 33

-------
 recycling  etching  solutions.  Lancy  (5)  used  an
 electrodialysis  cell  fitted  with  a cation-selective
 membrane to separate copper from chromic acid. The
 copper was recovered by electrowinning in a separate
 unit. Tirrell (8) suggested reduction of the Cr6+ content of
 a  spent etchant to Cr3+ in the cathode chamber of a
 diaphragm cell. When all the Cr6+ was  reduced, the
 copper was  plated  out at the  cathode.  The copper-
 depleted solution was then used as the anolyte, and the
 Cr + was  oxidized back to Cr6+. Fujii (1) suggested a
 similar  approach  for  exhausted  chromium-plating
 solutions. Gussack (2) used a diaphragm cell to reoxidize
 Cr3+ to Cr6+ in spent plastic etching solutions.
   The research  described herein  differs from previous
 work   in  that  the  chromium  is   oxidized   and
 contaminating metals are removed in a one-step process
 that minimizes the use of electrical energy. The authors
 have previously  reported (6-7) small scale  results where
 spent brass etchants, spent printed circuit board etchants,
 and rinse water from plastic etching operations, covering
 a  wide range of compositions, were  regenerated.  The
 apparatus for regeneration and recycling employed a
 diaphragm cell fitted with a cation-selective membrane.
 The solutions were placed in the anode chamber where
 Cr3+ was oxidized  to  Cr6+.  The acid concentration
 increased to  the normal value for a comparable  fresh
 solution. A portion of the contaminating metals migrated
 through the membrane into the catholyte. Essentially all
 the copper that migrated was recovered at the cathode.
 Regenerated  brass etchants evaluated by two companies
 equaled or exceeded the performance of fresh etchants;
 they were superior in the removal of red stain oxide.
  This paper describes the process research unit (PRU)
which  was developed to regenerate and recycle spent
etching solutions on an industrial scale.

EXPERIMENTAL PROCEDURES
Spent Etchants
  The  spent  etchants used in the PRU were obtained
from  brass finishing operations. The solutions were
originally prepared from sodium dichromate and sulfuric
acid. The compositions of these  solutions  are  given in
Table  I.  Elements  detected in  trace  amounts by
spectrographic analysis  included Ag, Al, Ca, Fe,  Mg,
Mn, Pb, Si, and  Sn.
TABLE 1
SPENT ETCHANT COMPOSITION
Composition, g/L
Sample Cr3" Cr6+ Cu
A 24 8.3 30
B 25 6.8 33
Zn SOt2~ value
13 168 0.4
13 191 0.4
The Process Research Unit
  A  flow diagram for the regeneration and  recycling
process is shown in Figure 1. Spent etchant is withdrawn
from the etching tank and pumped through a 1 to 3 /*m
pore size wound polypropylene cartridge filter.  The filter
step  reduces membrane plugging by fine particles and
thus  lowers cell resistance. The filtered solution is then
pumped into the anode chambers of a diaphragm cell.
                     T
              Spent etching solution
                                        Sulfuric acid
Diaphragm
Anode compartment
1
generated etching



cell
Cathode

solution

\

compartment
i

Copper metal
f
Base added
Zn+2 and

to ppt
^»r


                         To disposal

Fig. 1—Flow diagram for regeneration and recycling of spent etchants.


   Figure 2 is a schematic representation of a diaphragm
cell containing one anode chamber and two cathode
chambers. The anode chamber is fitted with Nafion5 427
cation-selective  membranes  to allow  ion migration
without  mixing the anolyte (the spent etchant)  and
catholyte (180 g/1  sulfuric acid). There is space for five
anode chambers in the diaphragm cell used in the PRU.
The   chambers  are  constructed  of Plexiglas. One-
sixteenth-inch thick Viton gaskets are used to seal the
membrane between the  chamber's flange  and frame.
When assembled, the chambers are contained in a 0.9 X
0.9 X 0.9 meter polypropylene tank which forms the
cathode  chamber.  A lead-6 pet antimony anodes  is
positioned in the anode chamber at the left. Two copper
cathodes (alloy 110) are positioned on either side of the
chamber. The remaining electrodes have been removed
so that the other anode chambers are visible. The ratio of
anode area to cathode area  to membrane area is 1:1:1.

                    Cation-selective
                    — membrane —
                                                                Copper
                                                                cathode
                     Lead-based
                       anode
Copper
cathode
                                                                                         V










Cathode
chamber
^
^
^

-------
Cathode  current  density  is  2.15  amp/dm2. At  full
capacity, the cell requires ~ 1,200 amp at ~3.2 volts.
  The PRU contains a intank filter unit, an etchant
holding tank,  a control panel, and  a  second etchant
holding tank. The diaphragm cell is located behind the
control panel. The pumps above each holding tank feed
filtered etchant into the anode  chambers. The pump
above the control  panel removes regenerated etchant
from  all anode chambers. The catholyte is circulated
using a pump located behind the panel. The hood above
the diaphragm cell  removes hydrogen,  oxygen,  and
chromic acid mist generated  by the cell.

RESULTS AND DISCUSSION
  Table II summarizes the results in three PRU tests. The
PRU  was operated with only two  anode chambers in
place  for tests 1 and 2. Five anode chambers were used in
test 3. The values in parentheses in the second column are
extrapolations to the flow rate for five chambers. For the
first day of each test, the PRU was run in a static mode
(no etchant flow) to oxidize most of the Cr3+. For the
remainder of the test, spent etchant was fed at the rate
indicated.  The  data  in  Table II  represents  flow
conditions.
  The power consumption figures indicate that about
13c worth of power is about $2.40. The rate of production
of sodium dichromate increased with increasing flow
rate.
  The catholyte used for Test 1 was reused in Tests 2 and
3. From an analysis of electrode efficiencies during start-
up and analysis of the product during the flow portions of
each trial, it appears that reuse of the catholyte is not
detrimental.  During extended operation of the PRU. A
bleed  stream will have to be taken from the catholyte. The
volume of this stream is estimated to be no more than 20
pet of the volume of etchant (of similar composition to
that given in Table I) processed. This stream contains no
Cr6+ and is far less concentrated in Cr3+, copper, and zinc
than  the spent etchant. It may  be disposed  of using
neutralization and  precipitation technology already in
place  in most finishing operations.
  Copper powder  (minus 100- plus 200-mesh)  was
recovered from the cathodes. The powder adhered to the
cathode as long as  current was flowing. The material
contained 85 to 90  pet copper. The major impurity  is
oxygen. Traces of Ag, Al, Ca, Cr,  Mg, Pb, Si, Sn, and Zn
are present. To show that the product could be converted
to a usable form, 2 pet carbon was  added and it was
melted, without agglomeration, in an induction furnace.
Ninety-five pet of the copper was recovered as an ingot
containing 99.7 pet Cu, 0.01 pet C, and traces of Ag, Mn,
Pb, Sb, and Sn.
  Previously reported  bench-scale tests and Table II
show that as the flow rate is increased the percentage Cr3+
oxidized decreases by a relatively  small amount. Thus,
the cost of regeneration  decreases as the requirements for
metal impurity removal decrease,  owing to the shorter
retention time required.  An examination of the results for
Test  2 (Table  II) shows that  the  flow rate,  and
consequently the amount of  Cr6+  produced, could be
nearly doubled if it was only necessary to remove ~20 pet
of the copper and zinc.
  There are two modes of etchant regeneration possible
with the PRU:
   1. The etchant may be used until completely spent and
then regenerated. After regeneration, the solution would
have to be  diluted to the  proper operating  level. This is
because the total  chromium  concentration is greatly
increased due to sodium dichromate additions to make
up for the Cr6+ reduced during the  etching  operation.
  2. The regeneration system may operate continuously
in  direct  connection  with  the   etching  tank.  The
temporary  loss  of Cr6+ by reduction to Cr6+ would no
longer have to be made up with chemical additions. The
specific gravity and viscosity  of the etchant would be
lowered, thus drag-out  would  be minimized.
  Bench scale and PRU tests have shown that operation
in mode 1 is feasible. Regenerated etchants evaluated by
two brass companies performed as well as or better than
fresh solutions.
  For successful operation in  mode 2, the regeneration
technique must  necessarily operate  at lower  etchant
concentrations, similar to freshly made etching solution.
In bench-scale tests using 1 volume of a brass etchant
(similar to samples A and B) diluted with 6 volumes of
water, Cr3+  oxidation,  copper and zinc removal, and
efficiency were equal to or better than what is reported
for the concentrated etchant in table II.

SUMMARY
  The technical feasibility of regenerating and recycling
spent   brass etchants  on  a  large  scale has  been
demonstrated. Using a diaphragm cell, 88 to 96 pet of the
Cr3+ was oxidized to Cr6+  and significant portions of the
contaminating  metals   were  removed.   Results  of
evaluations  of regenerated  etchants by industry were
excellent.
TABLE II
RESULTS OF PRU TESTS 1, 2, AND 3
Energy

o'+
Flow rale oxidation
Test (1/hr)
1' 2.6(6.5)
2' 5.7 (14.3)
32 7.3
'Sample A is feed material
2Sample B is feed material
(pet)
>96
88
92


Cu
removal
(pet)
41
20
31


Zn
removal
(pel)
41
23
28


Cr lost
to catholyte
(pet)
11
4
5


consumption
(kwhr/kg
Na2Cr2Or2H2O)
8.6
5.7
8.0


Na2Cr2Or2H2O
produced,
kg/hr
0.43
.70
.48



A node
efficiency
19
31
21



Duration,
days
3
3
7


                                                   35

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REFERENCES
1.  Fujii, A  Process for the Regeneration of Exhausted
   Chromium-Plating  Solutions  by  Two-Stage
   Diaphragm Electrolysis, U.S. Pat. 3,948,738, Apr. 6,
   1976.
2.  Gussack,  Mark C. Oxidation-Reduction  Process,
   U.S. Pat. 4,006,067, Feb. 1, 1977.
3.  Hallowell, J. B., L. E. Vaaler, J. H. Gurklis, and C. H.
   Layer. Assessment of  Industrial Hazardous Waste
   PracticesXElectroplating  and  Metal  Finishing
   Industries  -  Job Shops. Battelle's  Columbus
   Laboratories.  EPA Report PB-264349,  September
   1976, p.  128.
4.  Hicks, H. C., and R. A. Jarmuth. Regeneration of
   Chromated   Aluminum  Deoxidizers.   Boeing
   Commercial Airplane Company. EPA Report 660/2-
   73-023, December 1973, p.  5.
5.  Lancy, L.  E.,  and D.  C. Kruse. Electroaialysis
   Regeneration of Metal Containing Acid Solutions.
   U.S. Pat. 3,764,503, Oct.  9, 1973.
6.  Soboroff, D. M., J. D. Troyer, and A. A. Cochran. A
   One-Step Method  for Recycling  Waste  Chromic
   Acid-Sulfuric  Acid Etching Solutions. Proc. 33rd
   Annual Purdue Indus. Waste Conf., May 9-11,1978,
   pp. 758-763.
7.  Regeneration and Recycling of Waste Chromic Acid-
   Sulfuric Acid Etchants. BuMines RI 8377, 1979,  12
   pp.
8.  Tirrell, C. E. Process for the Electrolytic Reclamation
   of Spent Etching Fluids. U.S. Pat. 3,761,369, Sept. 25,
   1973.
9.  U.S. Code of Federal Regulations.  Subchapter NX
   Effluent  Guidelines  and  Standards:  Part  413X
   Electroplating  Point  Source  Category.   Federal
   Register, v. 42, No. 133, July 12,  1977, pp. 35834-
   35843.
                                                    36

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                            Liquid  Ion Exchange In
                    Metal  Recovery and  Recycling
                                         Lawrence V. Gallacher*
   Liquid  ion  exchange is a  relatively  new technique
 which combines the concepts of ion exchange and liquid-
 liquid extraction for the removal and recovery of metal
 ions from aqueous streams. Thg growing need for this
 technology today is the result of many factors, including
 government discharge  regulations,  rising metal values
 and  the  necessity  for  treating   increasingly  dilute
 solutions.
   The electroplating  industry in particular  is finding it
 more and more  difficult to deal with the problems of
 waste treatment and disposal, and at the same time, the
 economic need to regenerate and recycle valuable metal
 solutions. We are becoming increasingly aware of the fact
 that accepted  treatment methods  like the  removal of
 heavy metals from waste streams by generating mixed
 hydroxide, carbonate or sulfide sludge are ultimately
 undesirable. They generate potentially hazardous solid
 wastes,  both in the legal and the  technical sense, and
 waste valuable  resources. Ion  exchange  technology,
 particularly liquid ion exchange,  offers an effective
 approach to eliminate  the solid waste and  recycle  the
 metal values where they will be most valuable.
   I would like to start this presentation by describing
 four actual applications of liquid ion exchange in metal
 recovery. Then we will cover the basic principles of liquid
 ion exchange, the major types of reagents , how they can
 be applied to solve specific problems and what the future
 holds.
 Case I. (Figure  1)
   A strongly acidic solution of 0.2 grams per liter zinc in
 sulfuric acid is generated by a rayon plant. If the zinc is
 precipitated by neutralizing to pH 9.5 with caustic soda, a
 slimy, intractable sludge is generated. If lime is used, a
 tremendous volume  of calcium sulfate precipitate is
 produced, mixed with  a very small  quantity of zinc
 hydroxide, and the result  is a difficult solid disposal
 problem. The  problem is solved by first treating  the
 effluent  with  lime,  leaving it  weakly   acidic and
 precipitating calcium sulfate only. The zinc solution is
 then  mixed in two  stages with a solution of di-2-
 ethylhexylphosphoric acid (D2EHPA) in kerosene to
 reduce the zinc concentration in the effluent to less than 4
 ppm. The organic extract is  stripped with  a very low
 volume  ratio of sulfuric acid solution to regenerate the
 D2EHPA and produce a zinc sulfate solution containing
 80 g/1 which can be reused in the plant.
                  Recovery of Zinc
          From Rayon Manufacturing Waste
              FEED:  H2SOq SOLUTION, pH  0.5,
                     0.2 G/L ZN++
   ZNSOa SOLUTION,
   80 G/L ZN, TO PLANT
                               CA (OH)2
PH 5-6 ZNSOi) + CASOi)'2H20
     SOLUTION PRECIPITATE
                 ZN/ORGANIC
| STRIPPING
j
H2
so
I
S0t|
_'N
                D2EHPA
                IN KEROSENE
                                          REMOVE
                                          SOLIDS
      AQUEOUS EFFLUENT,
      ZN LESS THAN 4 PPM
Figure 1.
Case 2. (Figure 2)
   Mixed metal waste consisting of scrap, lathe turnings,
mill shavings and the like contain recoverable Mo, W,
Co,  Fe and Ni. The process involves five steps:
   1. Pyrometallurgical pretreatment, which converts the
     refractory metals Mo and W into their carbides.
   2. Electrolytic dissolution of Fe, Co, and Ni (using
     diaphragm cells and calcium chloride electrolyte
     solution with  anodic  dissolution of the  metals)
     followed by partial stripping  to concentrate  the
     CaCl2 electrolyte.
   3. Separation of Fe, Co, and Ni by extraction with a
     high molecular weight amine.
   4. Stripping the cobalt/iron organic extract with the
     weakly-acidic condensate from step (3).
   5. Cathodic deposition of Co and Ni in separate half
     cells. The stripped electrolyte then goes to step (2).
   The process produces a Ni/Fe mixture and a Co/Fe
mixture, which doesn't affect the market value of the Ni
or Co significantly. There is no  gaseous  or  liquid
discharge.
*Lawrence V. Gallacher
 King Industries, Inc.
 Norwalk, CT 06852
Case 3. (Figure 3)
  An ammoniacal leach liquor containing 12.8 g/1 Cu,
29.2 g/1 Zn and 110 g/1 NH3 at pH 10.1 was mixed in 3
                                                   37

-------
Recovery of Metals Value
From Treated Metal Scrap
TREATED PI
CATHODE _ CACl2__
NlCKEL | SOL'N
ETAL SCRAP
CAC12 CATHODE
[SOL'N] COBALT/ I RON
CATHODIC ANODIC
HALF HALF
CELL CELL
I
Nl
ELECTROLYTE
(CAC12)
CON
| FIL"
SOLID
Mo,W
CARBIDE
HER |
DILI
Co,F
CHLC
SOLI
1
EVAPORATOR
CATHODIC
HALF
CELL

1 1
COBALT/IRON
TE ELECTROLYTE
RIDE
TION
CONDENSATE
CONC.CO,FE,NI.
SOL/N, Cr=250 G/L
1

*
AMINE
EXTRACTION
1
A
Ni, CA
CHLORIDE SOL'N
3ENSATE
AMINE/METAL ijr
COB/
STF
TERTIARY 	 I
AMINE

iLT/lRON
IPPING
CONDENSATE
 Figure 2.
counter-current  extraction stages  with  an  equal
volumetric flow of a 38% solution  of an alkyl beta-
diketone in kerosene.  The  copper was quantitatively
extracted into the organic phase, but no zinc or ammonia
were extracted.  The organic extract was then washed
with a very small volume of dilute sulfuric acid (26.5 g/1)
to remove traces of ammonia and was stripped in 2 stages
with an equal  volume of solution containing 39 g/1
H2SO4 and 54.8 g/1 Cu.  The stripping acid was finally
passed through  an electrowinning cell to recover the
copper.

Case 4. (Figure 4)
  A crude  phosphoric acid stream  containing 58%
H3P04+vp.3 g/1 Ca++, 2.1 g/1 Mg++, 10.0 g/1 Al+++ and 9.5
g/1 Fe+++ is extracted with 5 volumes of an  extractant
mixture consisting  of 12%  di-2-ethylhexylphosphoric
acid (D2EHPA) and 19% dinonylnaphthalene  sulfonic
acid (DNNSA) in kerosene at 54°  C.  In a single stage,
4.4% of the phosphoric acid, 92% of the Ca+++, 42% of the
Mg+* and 12% of the Al+++ are extracted. The extraction is
carried through several countercurrent stages to remove
essentially all of the Ca++ and  Mg++ and much of the Al+++.
The extract is  then "scrubbed" with a 20% phosphoric
acid from the organic phase, and the scrub  solution is
later combined with the feed and recycled. The extract is
stripped with 1/10 volume of 10% sulfuric acid in 2 stages
at 55°  C to regenerate the extractant. A portion  of the
strip solution  is  removed  from  the system to be
neutralized and  fresh make-up acid is added to make
fresh  stripping  acid  solution.  The  phosphoric acid
product  produced  by  this  process is  suitable  for
conversion to high-quality super phosphoric acid  liquid
fertilizers.
Recovery of Metals
From Ammonia Solution
AMMO
i
1IACAL
Cu, ZN LEACH LIQUOR
COPPER EXTRACT, (NHi^SOi) SOL'N
TRACE NH3 ]
r 4
1 NH3 SCRUB |

EXTRACTION
STAGE 1
\
I
r
EXTRACTIO
STAGE 2
\
I
1
EXTRACTIO
STAGE 3
i
' ZN L
TO 2
i
r
IQUOR
.N REC
L

Si
v


Si
c
"•

DILUTE H2soi)
^CuSOi) SOL'N
"RIPPING
iTAGE 1 1
1
1
DRIPPING 1
>TAGE 2 1
* 1
BETA DIKETONE ACID '
EXTRACTANT i |
OVERY f 	 (
                                                         Figure 3.
   The four cases just described are actual examples of
liquid ion exchange processes which have been operated
on a large scale. They illustrate several  key points we
would like to make in this paper, namely:

   1. Recovery  of metals  by liquid ion exchange  is a
     realistic and economically viable concept.
   2. There are  a number of reagent types available for
     extracting metals under a number of very different
     conditions, i.e.:
     - from weak acid leach liquors
     - from relatively concentrated acids
     - from ammoniacal leach solutions
     - as anionic complexes
     - from mixtures containing many metals
   3. A "good"  process generates little or no secondary
     waste. Maximum recycling of all streams is utilized.
   4. Typical working  processes  bring a  number of
     chemical and engineering disciplines together.
THE PRINCIPLES OF LIQUID EXCHANGE
  Liquid  ion  exchange  is   somewhat  similar  to
conventional ion exchange using solid resins in that an
aqueous feed solution is contacted (mixed) with an active
reagent in  a mixing chamber  or column. In  this
operation, ions are extracted from the feed in exchange
for hydrogen ions or other transferable ions carried by
the liquid ion exchange reagent. The liquid ion exchange
reagent is water-insoluble, and  is generally used as an
"extractant" solution in a hydrocarbon solvent such as
kerosene. The actual "exchange" takes place when the
aqueous feed is mixed intimately with the extractant,
producing  an  unstable  liquid-liquid  dispersion  of
droplets of one phase in the other.  At the moment of
mixing, the  interfacial  area is very great, and  the
exchange process occurs  via a  three-step  mechanism
whereby:

  1. The hydrated or complexed metal ion diffuses to the
    aqueous/organic interface,
                                                    38

-------
         Purification of Crude Phosphoric Acid
       CRUDE PHOSPHORIC ACID WITH CA, MG,  Al
               SCRUB TO FEED
               EXTRACT: CA, MG
               Al, SOME HjPOtt
                                 DILUTE  PURIFIED
                                      H2SOi|, MG,  CA, Al
                                       TO LEACHING OR
                                        NEUTRALIZATION
N
STRIPPING ST. 2
k
t
              DNNSA/D2EHPA
              EXTRACTANT
                                  DILUTE
  PURIFIED
  PHOSPHORIC ACID
  PRODUCT
 Figure 4.
   2.  The ion is stripped (ideally) of its hydration layer
      and complexes with the liquid ion exchange reagent
      at the interface, making the interfacial transition,
      and,
   3.  The organic/metal complex diffuses into the bulk
      organic  phase.  Simultaneously, hydrogen ions or
      other labile ions associated with the reagent in the
      organic phase are transferred to the aqueous phase.
      In  fact,  the actual exchange takes place at the
      interface.
   Now we have successfully extracted the metal ion into
 the organic phase. The next  step usually is  to strip the
 organic, re-extracting the metal ions with an aqueous
 stripping solution.  In the  case of  acid  extractants,
 stripping is done with a dilute mineral acid. Often, as in
 two of the examples, the extractant phase picks up ionic
 or molecular species in addition to the desired ones, and
 these are extracted in a "scrubbing" step using a weak
 reagent before the stripping step.
  The final  step is to  recover  the metal  itself  and
 regenerate or dispose of the stripping solution. This  step
 is just as important as extraction and stripping, but is
 frequently given inadequate  attention.  The easy,  but
 expensive route,  is to neutralize the stripping solution
 and generate a neutral waste stream or sludge. The best
 approach is one which regenerates the stripping solution
 and recovers  the  metal directly,  electrolytically or by
direct reduction, or as an  insoluble salt. (Table I reviews
the 3  liquid ion exchange steps).
  Perhaps at this point you are wondering why we bother
to extract the metal from  the aqueous feed into  the
organic  phase, only to re-extract it into a new aqueous
                                                                                  TABLE I
                                                                 LIQUID ION EXCHANGE PROCESS STEPS
     1. Extract meta! into organic phase.

     2. Strip metal ions from organic phase.

     3. Recover the metal and regenerate the stripping solution.
                                                                                  TABLE 2
                                                                LIQUID ION EXCHANGE PROCESS CRITERIA
 1. The  process  must achieve the desired  result within allowed
   constraints.

 2. All  streams  in and out  and  products must be accounted  for
   completely.

 3. The  extractant system should have good long-term  operating
   characteristics.

 4. Interferences must be identified and treated in advance.
 phase. This is a good time to enumerate the benefits we
 can gain from liquid ion exchange beyond simple metal
 recovery. They are:
   a.  Increase the metal concentration in the stripping
      solution relative to the feed. By using high volume
      ratios of feed to extractant and extract  to strip
      solution, it is  possible to increase  the final metal
      concentration up to one hundred fold or more. This
      can be the key to metal recovery by electrowinning,
      crystallization, or precipitation.
   b.  Recover one  metal in  the presence of others.
      Frequently, the desired metal is present with a high
      background  level of other unwanted metals, e.g.,
      copper in the  presence  of ferric  iron.  In other
      instances, all of the metals may be valuable, but
      only one at a time. Selectivity in liquid ion exchange
      can be  obtained  by  using  specific  reagents  or
      combinations   of  reagents,  or  by   making
      adjustments in feed solutions or stripping solutions.
      We'll say more about thfs further on.
   c.  Recover  metal  from  an  ammoniacal   solution
      without  the  complexed  ammonia. Reagents  are
      available which extract Cu++, Ni++,  and Zn++ from
      ammoniacal  leach  solutions  without extracting
      ammonia. The metals can be obtained together or
      separately by controlling  either  extraction  or
      stripping conditions.
   d.  Change  the  counterion present  in the  feed to a
      different one. Sulfate can be exchanged for chloide,
      for example, by  extracting a sulfate feed  with  an
     acid extractant  and then  stripping  with dilute
     hydrochloric acid.
   Successful application of liquid ion exchange to metal
recovery requires careful attention to certain key details.
Before getting into a discussion of reagents,  we will
briefly review  these four criteria, since they are critical in
the selection of extraction reagents. (Table 2).
   First, the process must achieve the desired result within
the   allowable conditions  of  time,  temperature,
                                                      39

-------
concentrations,  pH,  equipment and  cost.  Cost is
obviously a paramount consideration. Fast extract-ion,
stripping, and phase separation mean small equipment,
small reagent inventory, and low cost. The same is true of
high extraction and stripping capacity.
  Second,  all feed  streams,  extractants,  stripping
solutions, and recovered metal values must be accounted
for completely. A  "cradle-to-grave" approach for all
streams is essential.
  Third, the extractant system should have good long-
term  operating characteristics. These include chemical
stability,  good  metal-complex  solubility,  very  low
solubility in feed and stripping solutions, and good phase
separation characteristics with no haze.  Solubility  and
haze are the principal causes  of extractant losses.
  Fourth, interferences must be identified and treated in
advance.  Interferences  can include co-extracted ions
which don't strip, oxidation or reduction reactions, solids
in the feed, and dissolved organics. For instance, organic
additives such as  amines or surfactants are likely to be
extracted  and a  gradual  deterioration  of  phase-
separation characteristics is likely. Possible answers are
to put in a carbon adsorption column before extraction
or to  strip the impurities afterwards.
 kerosene  requires  addition  of  modifiers,  e.g., 5%
 isodecanol, to prevent third phase formation.
     Dinonylnaphthalene sulfonic acid (HDNNS)
 C9Hi9  SO3H   C9H19  SYNEX  DN (King Industries)
   A strong acid with  excellent stability at temperatures
 below 60° C. Extracts well down to pH 1.0 with little
 selectivity.  Selectivity greatly  enhanced by combining
 with  other  reagents  including  D2EHPA,  LIX 63,
 SYNEX XB1.  Ammonium salt extracts well  from
 ammoniacal solutions.
                  Carboxylic Acids
              R-COOH Versatic  (Shell)
   Weak acids (See D2EHPA comments). Use in sodium
 salt form is restricted by solubility and emulsification
 tendency.
                Alkyl Benzotriazoles
   R   NH   N   N  SYNEX XB-1 (King Industries)
   Selectively extracts copper, nickel from neutral to
 acidic  media.  Mixtures  with  sulfonic  acids,
 alkylphosphoric acids, or carboxylic acids have higher
 selectivity and operate at lower pH.
TYPES OF LIQUID ION EXCHANGE REAGENTS
AND THEIR APPLICATIONS
  There are four fundamental classes of reagents used in
liquid ion exchange:
  1. Acids, which  extract  cations  in  exchange  for
     hydrogen  ions,  ammonium ions, or  other  metal
     cations,
  2. Chelating agents, which extract cations in exchange
     for hydrogen ions via highly specific interactions,
  3. Amines  and quaternary ammonium  salts, which
     extract  anions/anionic  metal  complexes  in
     exchange for anions,
  4. Neutral reagents, which function by solvating metal
     ions  directly or by forming complexes with other
     reagents, which  in  turn are more effective than
     either reagent.
  I will attempt to describe important members of each
class of reagents, their  important  characteristics, and
principal applications.


ACIDS
  These  are  all  high molecular  weight  compounds
containing large hydrocarbon groups which render the
acids and  their salts water-insoluble and also offset the
normal surface  activity  of  such materials.  Generally
speaking, the stronger the acid, the  lower the selectivity
but the better it extracts at low pH. When acids are used,
the  exchange of metal ions for hydrogen ions lowers the
pH  of the aqueous phase. This effect  severely limits the
metal-loading efficiency of weak acids. One answer is to
use  the acid in salt form (e.g.,  Na+ or NH4+); another is to
adjust the aqueous pH between stages. Representative
acid extractants are described below:
     Di-2-ethylhexyl phosphoric acid (D2EHPA)
     (C8Hi7O)2  P(O)OH  (Mobil, King Industries)
  A weak acid with good hydrolytic stability. Strong
affinity for Fe+++. Good  selectivity, dependent  on feed
pH. Requires use of salt form or buffering to obtain high
loadings. Biggest use is in uranium extraction, mixed
with trioctyl phosphine oxide.  Use as sodium salt in
AMINES AND QUATERNARY AMONIUM SALTS
  These reagents  are used to extract anions, usually in
the form of metal complexes. Stripping is accomplished
with aqueous salts or bases. Tertiary amines are most
popular, and  are used  in  protonated form in  acid
medium. Because of protonation, which results from
extraction of a mineral acid molecule (H2SC>4, HC1) from
the feed,
              R3N + HC1 = R3NH+CF
there is a  net transfer of acid to the stripping solution
when basic stripping solutions are used. However, phase
separation  is  much  better  with   basic  stripping.
Quaternary ammonium salts are  useful over a wide pH
range, even in basic media. However, because they can't
be deprotonated, stripping tends  to be difficult.
Tertiary Amines

R3N    Alamine  (Henkel), Adogen (Ashland)

  Biggest  use is in uranium recovery, where amines are
used to extract  the uranyl sulfate complex. Other uses
mostly involve extraction of chloride complexes. Some
selectivity  can be achieved by taking advantage of the fact
that some metals extract at lower chloride concentrations
than others.  For' example, at pH 2 and 40°  C, Alamine
336 extracts  ferric iron at 50 g/1 chloride, copper at 100
g/1, and nickel  only  slightly at 250 g/1. Sensitivity to
oxidation  in some systems.
Quaternary Ammonium Salts
R4N+X~  Aliquat (General Mills), Adogen (Ashland)
  Can be  used like amines, but do not require low pH.
More difficult to strip than amines. Applications tend to
be proprietary  and not well publicized.  Some use in
vanadium  refining.
DEVELOPING A LIQUID ION EXCHANGE METHOD
TO SOLVE SPECIFIC PROBLEMS
  Now  that  we  have reviewed important liquid ion
exchange reagent characteristics and criteria for applying
                                                    40

-------
                       TABLE 3
  DEVELOPING A LIQUID ION EXCHANGE METHOD


 1. Define the problem, the goals and the constraints.

 2. Select  candidate extractants, stripping solutions and recovery/
   disposal techniques.

 3. Perform laboratory shake-out tests.

 4. Modify compositions and conditions as needed and retest.

 5. Perform rough cost analysis.

 6. Run pilot-scale tests. Look for long-term effects and make necessary
   corrections.

 7. Review cost analysis.

 8. Design and construct process.
                                                              TABLE 5
                                           LIQUID ION EXCHANGE TROUBLESHOOTING-II
                                        Problem

                                        Stripping

                                        1.  Haze, slow phase
                                           separation

                                        2.  Solid Formation
                                        3.  Incomplete
                                           Stripping
                     Solution
                     1.  Raise temperature
                        Use reagent additive
                        Amines: Strip with base
                     2.  Use proper acid strip for solubility
                        Ammonia contamination: Scrub stage
                        Check interfering metals
                     3.  Increase temperature
                        Increase mixing time
                        Increase reagent concentration
                        Increase aqueous: organic volume ratio
                       TABLE 4
   LIQUID ION EXCHANGE TROUBLE-SHOOTING-I
 Problem

 Extraction

 1. Haze after separation
   Slow phase separation

 2. Solid Formation


 3. Low extraction
4. Low selectivity
 5. Organic contamination


 6. Unwanted metal or
   Inorganic Pick-up
 Solution
1.  Raise temperature
   Use reagent additive

2.  Use reagent additive
   Change solvent

3.  Increase mixing time
 Increase reagent cone.
   Increase organic: aqueous volume ratio
   Raise temperature
   Use more selective reagent
   Change solvent
   Raise Feed, pH
   Use salt form of extractant (acids)

4.  Use more selective reagent
   Decrease reagent cone.
   Decrease organic: aqueous volume
    ratio
   Change solvent

5.  Pretreat Feed: carbon or solvent
   Scrub stage


6.  Scrub stage,
   Change Conditions
   Change extractant
liquid ion exchange,  let's  consider how to develop  a
method to solve a specific problem (Table 3).
  The first step is to select  and  map out candidate
processes in rough detail giving preference to the simplest
approaches, those  which show least cost or maximum
return and those which lead to maximum recycling and
least  waste production.  Frequently  these criteria go
hand-in-hand, but often a level of complexity is required
to achieve lowest operating cost and waste.
  The next step is to perform extraction and stripping
"shake-out"  tests in  the  laboratory  using graduated
cylinders  or separatory funnels. We generally start with
equal volumes  of candidate extractant and feed in  a
graduated cylinder  with a  ground-glass stopper. The
extractant concentration is adjusted so that if all  the
 metal of interest is extracted, the extractant will load to
 about  60% of  its theoretical  capacity based on its
 molecular weight  and  the charge  on the metal.  The
 solutions are added at room temperature, the graduate is
 shaken by hand for one minute to form a liquid-liquid
 dispersion, and  then  set down to allow the phases to
 separate. At this point, it is important to note how rapidly
 the  separation occurs,  whether there is haze in  either
 phase, and whether  there is any  solid  formation,
 particularly at the interface. Slow phase separation and
 haze can usually be alleviated by operating at a higher
 temperature, or by the addition of certain additives like
 isodecanol  or tributyl phosphate, or a solvent change.
 Additives can usually solve solids problems. Increased
 temperature frequently helps the actual extraction as
 well, but neutral additives and solvent changes as often as
 not  impair extraction and selectivity. Tables 4 and 5
 present common problem  areas in liquid for exchange
 present common problem  areas in liquid ion exchange
 processes and potential solutions.
   After the liquid phases have separated, the next step is
 to carefully remove portions of both organic and aqueous
 phases and analyze  them to  evaluate the  extent of
 extraction and the selectivity. Suppose that the extent of
 extraction is good, but the selectivity between two metals
 is in the right direction but not good enough. Thus, you
 might be trying to extract iron from a solution containing
 50 g/1 nickel and 1 g/1 iron. Your analysis shows that the
 extractant takes out 0.5 g/1 iron and 2 g/1 nickel. This in
 fact shows good iron selectivity, since 50% of the iron is
 extracted while only  4%  of the nickel is extracted. A
 situation like this one is usually improved by adding a
 stage of countercurrent extraction.  If 100% of the iron
 and  10%  of  the  nickel had   been  extracted  the
 recommendation  would  be to  lower  the  extractant
 concentration or the volume ratio of extractant to feed to
 achieve  higher  loading  of the extractant.  Normally,
 increasing the loading increases the selectivity, essentially
 crowding out the less preferred ion. If you are extracting
 with a weak acid and the extraction is very low compared
 to the theoritical capacity of the acid, the problem may be
 caused by  a drop  in feed  pH   that  occurs during
 extraction due to the transfer of hydrogen ions into the
 feed.  The answer heye is to use the acid in salt form or to
adjust the feed pH between stages using caustic soda or
ammonia.  Another cause of low  extraction  is slow
                                                       41

-------
 extraction kinetics. This can be checked by repeating the
 experiment with longer shaking times. If the extraction is
 slow, that means bigger equipment.  Try raising the
 temperature or adding a reagent like DNNSA or LIX 63
 to reduce the interfacial tension (Table 5).
   Assuming  that we  have  achieved  satisfactory
 extraction in the shake-out tests the next step is to look at
 stripping. The same general rules apply here. In addition,
 if stripping is not satisfactory, increase the concentration
 of the active acid, base, or salt in the stripping solution. It
 is also very important to think ahead to the ultimate fate
 of the stripping solution. For instance, if we want to
 recover copper by electrowinning from a sulfuric acid
 stripping  solution,   we   should  have  a   copper
 concentration  of about 50 g/1 in  the stripping solution
 (called the pregnant electrolyte in the trade). This can be
 achieved by maintaining a base level of 40 g/1 and going
 up to  50 g/1 in stripping and  back  to  40 g/1 in
 electrowinning. Other options include:  direct use of the
 strip  solution  as-is,  hot  stripping followed  by re-
 crystallization of  the metal salt, hydrogen  reduction,
 vacuum stripping of the acid (HC1) and water to leave a
 metal salt, precipitation,  and finally, neutralization and
 disposal.
   Once the process concept has been worked out and
 demonstrated in the laboratory tests, it is time to take a
 hard  look at  the economics.  The system  should be
 evaluated for extractant losses due to solubility and haze,
 for these  are very important. Neutralization, make-up,
 energy and equipment costs should all be estimated to see
 if the process looks feasible.
   If so, the next step is to set up and run the process on a
 pilot scale long enough to see long-term effects. These
 may include: decomposition  of the reagent and a gradual
 deterioration in  performance,  accumulation of trace
 metal impurities in the extractant phase, accumulation of
 organic  or  other impurities from  the  feed  in  the
 extractant,  or  the   development   of  "curd"  (an
 undetermined solid phase at the interface). Solutions to
 these  problems  may  not come  easily. Slight reagent
 decomposition  or solubility loss  can be corrected by
 partial  withdrawal and make-up.  Accumulation  of
 unwanted metals  ions may require a change in the
 stripping solution or addition of a scrubbing step. The
 same is true of organic impurities, or these might require
 pre-treatment of the feed with a carbon-absorption step
 or a  solvent-extraction  step. "Curd"  can usually  be
 eliminated satisfactorily  by the right  additive in the
 extractant.

FUTURE PROSPECTS  FOR  LIQUID ION  EX-
CHANGE IN METAL RECOVERY AND RECYCLING
  In this paper we have attempted to introduce you to
liquid ion exchange principles, showing  you a minimum
of abstract theory, what can be done and has been done,
 what reagents are available and what each can do and
 can't do, and how to work out a process to solve your own
 problems.
   Looking ahead,  what does the future hold for this
 technology?  As   we  see  it,  the  economic  and
 environmental  pressures are building rapidly to  find
 better ways to recover metal values from process streams
 and waste streams. Making metal hydroxide, carbonate
 or sulfide sludges doesn't look like an acceptable long
 term answer to the environmental problem and is no
 answer at all to the economic problem. These sludges are
 notoriously  hard to handle and should go to secure,
 hazardous-waste  landfills,  since they always have the
 potential  of releasing toxic concentrations  of  heavy
 metals under acid conditions.
   Liquid ion exchange is one of several approaches to the
 recovery of metals, but it appears to have  the greatest
 potential for a general solution to the recovery problem.
   There will be difficulties along the way, however. Right
 now it looks like liquid ion exchange is beginning to
 acquire recognition as a useful technique. Unfortunately,
 there have also been some false starts in using it - mostly
 because of ignorance of available information or not
 considering the total system. However, the last five years
 have brought  rapid progress in the understanding  and
 utilization of liquid ion exchange techniques in this area,
 and we are confident that progress will continue. Bear in
 mind that in  other  fields  like  primary copper  and
 uranium refining, liquid ion exchange has played a major
 role for over five years.
   Certain applications look very interesting right now.
 For example, the mixed metal sludges referred to  before
 can be leached with either sulfuric acid or ammonia to
 generate feed liquors which certainly can be treated with
 liquid  ion  exchange  to  recover  valuable  metals  like
 copper, nickel,  and zinc separately.
   I hope that this presentation has helped to inform you
 of developments  and useful applications in liquid ion
 exchange.
REFERENCES
1.  H. Reinhardt, H. Ottertum and T. Troeng,  Proc.
   Appl. Chem. Treat. Sewage Ind. Liq. Effluent Symp.,
   Int. Chem. Eng., London, 1975, p Wl. (The Valberg
   Process).
2.  H. Reinhardt.  Chemistry  and Industry, p. 210, 1
   Mar.  1975. (The Gullspang Process).
3.  Preliminary Report.  XI-54.  A  New Reagent for
   Metal   Extractions  from  Ammomiacal Solutions
   General Mills Chemical, Inc.
4.  J. L. Bradford and F. Ore, US Patents 4,053,564 (to
   Occidental Petroleum Company), Extraction Process
   for Purification  of Phosphoric Acid.
                                                    42

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  Achieving  Effluent Criteria—Not Final  Answer
                                      A. F. Lisanti and R. Helwick*
   Much attention has been given to the treatment of
 wastewater. Wastewaters are characterized and studies
 conducted to optimize the treatment processes in order to
 assure achievement of effluent limitations with the least
 possible cost. In the treatment of wastewaters, especially
 from metal finishing plants, metals are precipitated and
 removed as a sludge. The hauling and disposal of that
 sludge, however, have not received as much emphasis as
 that of the wastewater treatment processes. Accordingly,
 many plants are not equipped with the sludge dewatering
 facilities or the facilities are not the most cost effective.
 One reason is that the characteristics of the sludge are not
 adequately known  before the  wastewater  treatment
 facilities  are  installed.  With  the impending  sludge
 disposal requirements  as  outlined  by the  Resource
 Conservation and Recovery Act and the increasing cost
 of contract disposal, nevertheless, sludge handling and
 disposal must be addressed with the same zeal  as that
 afforded to the wastewater treatment processes.  The
 sludge should  be characterized  and studies  made to
 optimize sludge handling and dewatering  systems. In
 addition, evaluations should be made of sludge disposal
 alternates including  recovery processes. These  efforts
 should reduce the cost of sludge disposal.

   Other papers presented at the conference will discuss
 existing or pending regulatory requirements for sludge
 disposal. As such, this paper will not address that phase
 but presents a summary of capital and operating costs
 currently incurred  by representative metal  finishing
 plants for sludge disposal. The  plants selected  for
 discussion  have been designed  using  well publicized
 techniques of inplant wastewater flow reduction and best
 practical treatment  technology. The  solids dewatering
 facilities which  include the use of filter presses, vacuum
 filters and  diatomaceous earth type of pressure filters
 were  designed  based on  an  evaluation of  alternate
 schemes and data accumulated in treatability studies.
  Table I lists the sludge quantities handled by each of
 the plants. It tabulates the volume of sludge entering the
 dewatering process, the solids content of the sludge, the
 solids content of the cake obtained by the mechanical
 dewatering equipment and the quantity of cake that must
 be disposed of.

  Plant  A referred  to  in  Table  I  batch  treats the
 wastewater and passes  the unsettled slurry through
*A. F. Lisanti and R. Helwick
 Chester Engineers
 Coraopolis, PA
pressure filters precoated with diatomaceous earth. Since
filtration of the wastewater is necessary to attain effluent
limitations, the use of diatomaceous earth filters not only
accomplished that goal but at the same time dewaters the
solids. Plant B utilizes a continuous treatment system.
Since the concentration of suspended solids generated by
the treatment processes is of such a level as to preclude
direct  filtration  and  dewatering as  in Plant A, the
wastewater  is  clarified  before  filtering through  a
diatomaceous  earth type  of pressure filter. The sludge
from the clarification process is conveyed to a thickener.
The thickener also  receives the diatomaceous earth from
the pressure filter. After gravity thickening, the solids are
dewatered by a filter press.  Plant C treats its rinses in a
bath operation. The sludge from this process  is mixed
with spent concentrated acids which are neutralized and
dewatered by a filter press. In Plant D, the wastewater is
clarified and the underflow conveyed to a storage tank
for subsequent dewatering by a filter press. For Plant E.
the underflow of the clarifier is gravity thickened and
dewatered by a vacuum filter.

   Table  2 lists  the construction  costs for the total
treatment facilities, the cost associated with the sludge
equipment including housing for that  system and the
percentage of  the  total cost of the treatment facilities
associated  with  the sludge handling  and dewatering
equipment.

   Currently, each of the plants are hauling the dewatered
solids to an approved landfill site. Table 3 illustrates the
costs incured by  each of the plants for disposal of those
solids. These costs include the  pick-up, hauling and
placement charges. As noted in the table, Plant C instead
of disposing of its solids in a local approved landfill has
the option of hauling the solids to another plant within its
corporation for metal reclamation.

   As a means of comparing the plants operating costs
associated with the treatment of wastewater and the costs
applicable to the solids handling and disposal, Table 4 is
presented. The costs in this table include an estimate of
the manpower devoted to the wastewater  and solids
handling portion of the treatment system. The costs do
not include amortization of the equipment.

  As demonstrated by the cost comparisons, the sludge
handling and disposal facilities are not only a significant
factor  in  the  construction costs for  the wastewater
treatment  facilities, especially for the smaller metal
finishing plants, but play a major role  in the operating
costs. Nevertheless, without the sludge handling and
dewatering facilities, the disposal costs for the solids
would be significantly increased. For example, Plant C
                                                    43

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generates some  153,600 pounds per week of sludge at a
local landfill site would cost about $6,150 per week. By
dewatering the solids, the weight of sludge to be disposed
of its reduced from  153,600 to 76,200 pounds per week
and the disposal cost decreased from $6,150 to $3,050 per
                            week. This savings in disposal cost offers a good payback
                            on the  capital  investment of  the solids dewatering
                            facilities. It is advantageous, then, to not only optimize
                            wastewater treatment processes, but the sludge handling,
                            dewatering and disposal options for each plant.
TABLE 1
SLUDGE QUANTITIES



Plant A
Plant B
Plant C
Plant D
Plant E


Dewatering Method
Pressure Filtration (DE)
Filter Press
Filter Press
Filter Press
Vacuum Filtration

Sludge Volume,
gpd
10,000
340
2,285
234
1,780

Solids of Sludge,
wt. %
0.03
9
15
1.9
8.7

Cake Solids,
wt. %
40
32
30
15
22
Quantity of
Cake Generated,
cuft/wk
13
150
941
14
620


TABLE
2

CONSTRUCTION COSTS

Plant A
Plant B
Plant C
*48% is of spent
Design Flow,
gpd
25,000
238,000
*4,000
concentrated acids.
Treatment Facilities,
$
450,000
1,900,000
940,300
Dewatering Facilities,
$
97,000
240,000
158,000
% of Total Facilities' Cost
For Sludge Handling
21.6
12.6
16.8
    Plant A


    Plant B

    Plant C

    * Plant C (Alternate)
                     TABLE 3
            SLUDGE DISPOSAL COSTS

       Costs include hauling and disposal charges

Quantity of Sludge, tons/mo     Disposal Cost, S/mo

            1.0                       1,290
            12

            165
            165
 1,800

13,200

24,750
      Disposal Method

Drummed and hauled to approved
  landfill

Hauled to approved landfill

Hauled to approved landfill

Hauled to metal reclamation plant
    *Cost are for hauling. Does not include cost of metal recovery nor value of recovered metal.
TABLE 4
OPERATING COST COMPARISON
Entire Treatment Facilities,
$/year
Plant A 34,000
Plant B 138,000
Plant C 27,860
Solids Dewatering and
Disposal Portion, $/year
16,000
50,000
13,200
% of Entire Cost For
Solids Disposal
47.0
36.2
47.4
                                                        44

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                         Luncheon  Presentation:
 The  Resource  Conservation  and Recovery Act
                                         Rebecca Hanmer*
  It is a pleasure for me to be here and to have this
opportunity  to  share  a  few thoughts  with you on
hazardous waste. This is my first formal opportunity to
meet with representatives of the metal finishing industry.
However, in my  former job as Deputy Administrator of
EPA's Boston Office, I was keenly aware of the economic
importance of the industry in New England and thus
interested in the means by which electroplaters  were
seeking solutions to pollution control requirements.
  For years, industry has been dealing with requirements
to protect the Nation's air and water. Today, I want to
talk with you for a few minutes about the law that closes
the  loop, The Resource Conservation and Recovery Act:
RCRA.
  I  will give  you a brief history of  RCRA, provide
information about the upcoming regulations, and the
EPA Regional Office role, and comment on something I
believe to be of overriding  importance—especially in this
program. That is the need to work together. We need to
communicate with each other and with the public. For
this new set  of  requirements and protections - vitally
needed - will affect us all.
  RCRA became law in 1976 and is structured to ensure
that from now on our society takes its  hazardous waste
management   responsibilities  more  seriously.
Unfortunately, it was not until the Act was about two
years old, and  the  Love Canal tragedy  forced our
attention on the magnitude of the residues of past neglect,
that we  noticed RCRA's limitations. Except for an
imminent hazards provision, the Act does not address
critical problems which recently have come to light from
a legacy of careless waste management. We know now
that there are two hazardous waste problems — The one
we have inherited and the one RCRA is intended to solve.
We  know also that neither can be neglected; except at the
cost of the extreme peril to ourselves, our children, and
people yet unborn.
  We produce 57 million  tons of hazardous waste  each
year. We estimate there are more than 750,000 generators
of hazardous  wastes,  10,000 transporters, and 30,000
treatment, storage, and disposal facilities. At least 90
percent of the hazardous wastes currently produced are
disposed  of improperly and unsafely.  There are up to
50,000 uncontrolled closed and existing sites.
  More than 60,000 chemicals are now in common use in
this  country; thousands more are registered each week.
•Rebecca Hanmer
 Regional Administrator
 U.S. EPA Region IV - Atlanta
The adverse effects of mismanaged waste can reach us
through direct contact, through the air we breathe, the
food we eat  and the  water we drink. It is of critical
importance that we keep waste from  seeping into the
groundwater. About half of the drinking water supply in
this country is taken from groundwater. Twenty percent
of the population drinks groundwater untreated.
  As you probably know, because EPA failed to produce
RCRA regulations within eighteen months as stipulated
in the law,  civil actions were brought against  the
Environmental  Protection Agency  by  the  State  of
Illinois, the Environmental Defense  Fund, and  others.
Last October, EPA's Administrator, Doug Costle, in a
quarterly affidavit on EPA's progress in developing final
regulations,  said,  "Among the  many  pressing
environmental problems currently facing EPA and the
Nation, I consider hazardous waste the most serious."
  He also  pointed out in the affidavit  that we received
more  comments  on  RCRA than on any proposed
regulations in the history of the Agency. At that time we
had 1,200 sets of public comments, some  of which were
hundreds of pages in length.
  At the same time we have been involved in developing
RCRA regulations, we have had to begin to deal with the
problem of  closed  and  existing uncontrolled sites.
Working with the Department of Justice and the states,
EPA has initiated a remedial and enforcement program
directed against  hazardous  waste  sites which pose
substantial risk to public health and the environment.
Regional offices have  been required to redirect many
work years towards this effort. Hundreds of sites have
been investigated and  a number of major enforcement
actions have been initiated by the EPA regions.
  To provide funds for the clean-up of abandoned sites
and to permit a more rapid response where health and the
environment are threatened, EPA developed legislation
which was submitted by the President to Congress last
June to establish a multi-million dollar "superfund."
Hearings on the proposal have been held by  several
congressional committees, on several different bills and
committee mark-up is  underway.
  But,  back to RCRA. The  original Federal law was
born in 1965. That means we are now on the verge of
beginning to move against hazardous waste fifteen years
after the first federal law to  deal with the solid waste
problem was  enacted.
  In 1970,  the Congress amended the solid waste law to
call for a  comprehensive investigation  of hazardous
waste management practices in the United States, with
formal reports to be submitted to Congress.
  It wasn't until 1975 that the need for hazardous waste
regulation  was acknowledged by important segments of
                                                 45

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 industry and public interest groups. A Federal system for
 such regulations  was authorized by  the solid  waste
 amendments  of  1976  that  formed  the  Resource
 Conservation and Recovery Act.
   Today, we have the law and we have some of the
 regulations. More regulations will be issued this month,
 with the  final regulations for  writing RCRA  permits
 expected  in October 1980.
   The law  allows States to assume delegation of the
 program, and we are working hard with the States to this
 end.
   What  is the role  of EPA's  Regional Offices in the
 RCRA program: In brief, we are the implementing part
 of EPA. The 10 regions will be implementing the RCRA
 regulations either directly or, where State programs have
 been approved, indirectly through State overview. The
 direct role consists of:
 •  Assisting  persons  to understand the regulations and
   how different industries are affected
 •  Monitoring compliance with interim status notifica-
   tion and manifest requirements.
 •  Enforcing where necessary
 •  Issuing RCRA permits
   We will  help States set  up  RCRA programs and
 approve State programs where possible to take over the
 direct tasks. We administer State program grants.  After
 the  States  take  over, we  help them with difficult
 situations and oversee progress.  RCRA allows a State to
 qualify early  to take the  program  through  interim
 delegation.  That means the State can run the  RCRA
 program even if it needs to make some legal or regulation
 changes in order to get the full delegation. The State must
 have a program to  start out that meets most  RCRA
 requirements and  a definite timetable for completing
 improvements in 2 years.
   In Region IV, we estimate 5 of our 8 states now will be
 able to achieve interim delegation this year.
   I've been asked to give you a hint about the upcoming
 regulations,  I believe you talked about this at a morning
 session, so I  will just summarize  briefly. EPA has already
 issued the regulations for the manifest system, which go
 into effect at the end of October 1980.  Regulations
 defining  what a  generator  is and  a public notice
 explaining the notification procedure were also issued on
 Feb.  26.  On April 30,  EPA   is going to  issue the
 regulations that define (1) hazardous wastes, (2) set our
 requirements for States to get authorization for running
 the program, and (3) contain requirements for hazardous
 waste treaters, storers and disposers to get interim status
 pending review for a RCRA permit.  The procedures for
 the RCRA  permit program are going to be  issued on
 April 30 as part of the consolidated permit regulations.
   I can't give you the definition of hazardous waste in
 advance  of  the rules,  but you  have some idea of the
 impact on your industry from the proposed regulations
 of  last December.  Metal  finishing  sludges contain
 elements  that  will likely fall  into  the  definition of
 hazardous waste, such as chromium, cadmium and lead.
 Metal finishing wastes  may also fall into the hazardous
waste characteristics  of ignitability and corrosivity.
   Early in May, Washington EPA is going to mail out
several hundred thousand packages to names on our list
of  generators,  treaters,  transporters,  storers  and
disposers. These packages will tell people how to comply
with the notification and  interim status requirements.
   For generators, transporters,  treaters,  storers and
disposers: these persons  must notify the EPA regional
office  within  90 days  after  the  regulations defining
hazardous waste are promulgated (around July 30). Also,
treaters, storers and disposers have to submit part of the
permit application to receive interim status.
   Don't assume, if you don't get a package, that you're
off the hook. Persons who generate,  transport, treat,
store or dispose of hazardous wastes must meet  the
regulations. EPA  regions will be required to  enforce
against those who  don't.
   I urge you to attend  one of the workshops that  are
going  to be  held  to  explain  the regulations.  The
Washington, DC workshop will be on June  2 and  the
Chicago workshop will be June 6. The regulations should
be published in the first two weeks in May in the Federal
Register. Regional EPA staff will be learning along with
you, and will be able to provide technical advice. EPA
Headquarters  is also planning  to  set  up training
programs to help businesses who may be hard hit to learn
about applying. I was delighted to learn that AES is a
part of this program.
   The arduous, long-term task of dealing with hazardous
waste is just beginning. Potentially, there are many things
that can be done with hazardous wastes besides burying
them into a landfill that will meet RCRA's requirements.
As is already recognized in your industry, certain waste
can be recycled and sent back for reuse.  Other wastes can
be used by others without processing. Wastes can be dealt
with by incineration, chemical neutralization, separating
or blending to yield a useable  product  or supplemental
fuel  for firing  industrial  furnaces,  and  "Biological
destruction," in which micro-organisms consume the
hazardous material and render it harmless.
   Ideally, disposal should be the procedure of last resort.
Since  RCRA's  regulations  will  make this procedure
much more safe but also more expensive than it's been
before, eventually the widespread use of other methods
should be achieved. For a good while, however, there is
no question that the procedure of last resort will be the
procedure of greatest use. Moreover, proper disposal will
be needed even years from now when we  will have
drastically  altered  our perceptions and practices with
regard to wastes. There will still be a great many materials
that are too low in value to recycle,  too difficult to
degrade or to inject into deep wells and too contaminated
with nonflammable materials to incinerate.
  Proper  burial under RCRA will be a far cry from
dumping.  Serious  attention  to  properly engineered
landfills with liners, covers, gas generation techniques
and  monitoring operations  will come  into being. The
chemical solidification of wastes, now used for  only a
very small percentage of hazardous  materials,  will  no
doubt become more popular. And disposal of the wastes
will not end the scrutiny process. Disposal site  operators
will have to monitor and maintain closed sites for many
years to make sure that there is no migration into soil or
drinking water supplies. There will be liability for each
incident of damage that occurs while the site is operating.
And money will have to be set aside to close and maintain
inactive sites. Violators will be subjected to serious civil
and  criminal penalties.  RCRA calls for truly drastic
changes in the way we deal with wastes.
  Yet the entire promise and purpose of the Act would be
aborted by the  strong and widespread  public  view that
treatment and disposal facilities are all right, provided
they are located on another planet or at least on another
                                                    46

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continent. And that  brings us to the common  cause
between industry and government and the need for a
genuine on-going dialogue.
  In  order  to  implement  RCRA,  industry  and
government are going to have to come together. Our
challenge is to show the public that we can maintain our
commerce, that we can build and maintain safe, effective
hazardous waste management facilities. We must show
that we can manufacture and use chemicals and other
goods  without  poisoning our groundwater,  without
creating a  no-man's  land, and without  shipping our
problems to the moon. We are not  going to be able, in my
view,  to  force communities  to take  hazardous  waste
facilities.  We - you and I - are going to have to find
incentives to offer these communities. And we're going to
have to prove ourselves.
  I have no doubt that EPA will be sued on the RCRA
regulations. I have no  doubt that, as we progress with the
law  we will discover  ways  our regulations can  be
improved. However, I also feel the imperative is with us.
There is a level of public concern about hazardous waste
that compels EPA - and industry - to act - now.
  I'll close  with this. In the January issue of Chemical
Times  and  Trends,  the  chairman of  the   du  Pont
Company, Irving S. Shapiro, refers to an ancient Chinese
saying which goes like this—"May you live in interesting
times." Mr. Shapiro went on to say, "The seventies have
been too interesting for comfort, and the eighties may
prove more interesting still." Then, he added, "The key to
profitable  operation in the  eighties  will be effective
communication  with  governments  and  other
constituents." I think he's right.  To make our society
work, business  has  got to talk with  government and
government with business. Let's keep it us.

Thank you.
                                                   47

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      Resource Conservation and  Recovery  Act
                                           Kurt W. Riegel*
  I must admit that when I was asked to come to Florida
to explain the RCRA regulations to members of the
American Electroplaters' Society, I felt quite good about
the confidence the Environmental Protection Agency
had in me. After holding quite a few discussions with
people in the electroplating  industry, however, and
hearing of the practical problems many of you have in
disposing of your wastewater treatment sludges, I have
come  to the conclusion that, in reality, the agency was
looking for somebody expendable.
  Whatever  the motivations behind EPA's sending me
here, however, today I am going to try to help you make
some sense out of what must be a rather confusing picture
to everyone—the  hazardous  material waste  disposal
regulations,  resulting from the Resource Conservation
and Recovery Act—or "RCRA".
  I will first go into the basic provisions of RCRA which
affect the electroplating industry. Then I will discuss the
specific regulations that have been promulgated to date.
At the completion of my talk, I will have some time for
questions—which I will answer to the best of my ability.
Howard Schumacher tells me that there will also  be
round table sessions in which I and members of the Office
of Solid Waste will be  available for further discussions.
  First of all, I would  like to make it clear—and I can
speak for all of EPA in this—that we  at EPA do realize
the importance of the electroplating industry to the United
States. There is no doubt that the metal finishing industry
is a key link in the industrial strength of the United States.
I also want to assure you that I am not going to spend a
great deal of time talking about the Love Canal incident
with you. I fully realize that there are no electroplaters
involved in that very unfortunate  situation and I also
realize that the wastes from electroplating operations are,
in many ways, different from  those in the organic
chemical industry.  I also know that some wastes are more
hazardous than other wastes, and that a waste which is
hazardous when disposed of  by  one method may  be
nonhazardous when disposed of properly.
  I also feel that there  is another major difference
between  the  electroplating  industry  and the kind  of
attitude  that  led  to  Love  Canal   and  other  very
unfortunate  situations. I  have been briefed on the joint
AES/EPA   characterization  of  sludges  from  your
wastewater treatment operations and your  continuing
effort to determine cost effective but safe methods for
disposing of these wastes.  I understand that the joint
AES / EPA cooperative effort arose from needs expressed
at this same  conference two years ago. If this conference
*Kurt W. Riegel
 Associate Deputy Assistant Administrator
 Office of Environmental Engineering and Technology
 Environmental Protection Agency
can produce  that  type  of cooperation  between the
industry and the Government, I want to say that I am
very happy to be a  part of it.
  Now, what about the need for a national program to
control the disposal of wastes? Congress felt there was a
need for a national program, and passed the Resource
Conservation  and Recovery Act of 1976. I think that
subsequent events have verified that this nation does need
to control how  industries  dispose of wastes  that are
hazardous. There  are  just  too  many  instances  of
individual corporations or persons acting irresponsibly.
Those actions have resulted in tragic effects to people and
to the  environment. As  always, when  regulations are
needed, it is very difficult  to  decide just how far the
regulations should go, and the agency is trying ernestly to
strike an  appropriate balance  between protection of
public health and the environment on the one hand and
the burdens on industry on the other. RCRA gave EPA
the specific responsibility of defining what wastes really
were hazardous, and how  they should be  controlled.
From  1976 until now,  the agency  has  been  deeply
involved in sorting  out the proper methods of control.
Key sections  of  RCRA   which  apply  directly  to
electroplaters are shown in  Table I.
  Section  3001 of RCRA required EPA to develop and
promulgate criteria for identifying the characteristics of
hazardous wastes and the listing of hazardous wastes. In
developing these criteria, EPA was instructed to take into
account toxicity, persistence and degradability in the
environment,  the potential for accumulation in tissue,
and other factors such as flammability and corrosiveness.
Congress also directed EPA to revise these criteria from
time to time and to make changes as may be appropriate.
  EPA  has already proposed  criteria for hazardous
wastes  and many  of you  have  commented  on the
proposed criteria. These comments and other related
Table 1
Key Sections of Resource Conservation and
Recovery Act (RCRA, PL 94-580)
Section
3001
3002
3003
3004
3005
3010
Regulation
Number
261
262
263
264
265
266

Criteria for listing as hazardous
Standards for generators
Standards for transporters
Standards for disposal facilities
Permits for disposal facilities
Preliminary notification
requirements
                                                   48

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 information are being used  to  derive the final 3001
 regulations. For those of you who were not involved in
 this stage  of the  regulatory procedure, we essentially
 approached the problem of defining hazardous wastes by
 two proposed methods.  First we proposed  a  list of
 industries which generated wastes which we felt had the
 potential for being hazardous. Electroplating wastewater
 treatment sludges were included on this list. These are the
 so  called  categorical  listings  of hazardous wastes.
 Second, we proposed a procedure for those wastes that
 were not listed. For unlisted wastes, generators were
 obliged to test or  otherwise assess  their wastes against
 certain characteristics. One of these characteristics was
 toxicity,  determined  through  laboratory extraction
 under specified conditions.  The  extract was  to be
 analyzed and  tested to determine if it is hazardous.
 Because electroplating sludges were listed as a hazardous
 waste, the proposed regulations did not require use of the
 toxicity  characteristic and the extraction procedure to
 designate these wastes as hazardous.
  I would like to make clear that the regulations  for
 Section 3001 have  not yet been promulgated. They have
 been proposed only,  and the agency has been considering
 the comments made by the  public on these  proposed
 regulations. At one  time there was  hope that  we  might
 have the final promulgated 3001 regulations ready to be
 presented  at this  conference;  however,  the current
 scheduled date for promulgation for these regulations is
 now April 30,  1980.
  The next two sections—the standards for generators
 and the  standards for transporters—were promulgated
 on  February 26, 1980,  and I will discuss them in more
 detail later. The first  phase of the Section 3004 Standards
 for  Disposal  Facilities  is   also   scheduled to  be
 promulgated  on  April 30,  as  are the Section  3005
 permitting procedures regulations, which will be a part of
 a consolidated permit procedures regulation  covering
 RCRA,  National   Pollutant Discharge  Elimination
 System (NPDES), and  Underground Injection Control
 (UIC) permits. The first phase of the 3004 standards will
 establish interim status requirements.  The second  phase
 of  these standards  will  set  the  requirements   to  be
 incorporated into  permits. These will be  promulgated
 around October 30,  1980, and will become effective six
 months thereafter.
  People in regulatory  agencies are limited by law in
 discussing regulations when the public comment period is
 closed and the regulations are undergoing final revision.
 Unfortunately, I  am under  these  restrictions   today
 regarding Sections  3001,  3004  and 3005. This is a
government-wide policy and not just an EPA practice. It
is part of the administrative law which governs how the
 federal regulatory  agencies interact with the public. It
 allows the agency to fulfill its obligation to remain fully
 open to the public for an announced period of time for
 information   that   may  be  used  to  advantage   in
 establishing  a regulation. At the close  of the  public
 comment period, a regulatory agency must  develop its
 regulations by concentrating solely upon the information
 which has been presented, it cannot accept further data
 or comments.
   Today we are free to discuss Sections 3002, 3003, and
 3010, since they have been promulgated. We can discuss
 background  and answer general questions related to
 Sections 3001, 3004 and 3005, but I cannot  discuss  the
 specific regulations.
   Let's now discuss the Section 3002 regulations which
 apply to generators of the waste. This section sets forth
 the responsibility of the generators  in  the  "cradle to
 grave" control system of hazardous wastes. Section 3002
 requires the Administrator of EPA to establish certain
 standards for generators. First, EPA must  establish a
 manifest system which would assure that the waste is
 designated for delivery at a permitted  storage facility.
 Second, there must be  appropriate containers with
 proper  labels for  hazardous waste. Third,  there are
 requirements for record keeping which would identify the
 quantities  and  disposition of the hazardous wastes.
 Fourth, general chemical composition information must
 be provided to parties who will be transporting, treating,
 or storing the wastes. The regulations require that, prior
 to transporting, treating, storing  or  disposing of any
 hazardous  wastes, the generator must obtain an EPA
 identification number. This number is to be assigned by
 the agency after receiving  the generator's  hazardous
 waste notification.
   Table 2 outlines the responsibilities of generators who
 ship hazardous wastes offsite.
   First,  the  generator is responsible  for  preparing a
 manifest,  which  must  identify  the  generator,  the
 transporter, and the designated disposal site. In addition
 there is some required information related to the nature
 of the waste.  The manifest also contains the generator's
 identification number.
   In packaging the waste to be shipped, the generator is
 responsible  for  complying  with   DOT  packing
 requirements which  have been concurred on by  EPA.
 The other major responsibility of the shipper is that, if
 within 35 days he does not receive his signed copy of the
 manifest by the intended receiver of the waste, he must
contact  that  receiver to  determine if  the  waste was
received. If the  manifest  receipt copy is not received
within 45 days, then the generator must file a report with
                      Table 2
   Generators Who Ship Hazardous Wastes Must:

  • Determine if a waste is hazardous
  • Prepare a manifest
  • Comply with DOT packaging requirements
  • Contact the designated receiving facility if receipt copy
    is not received in 35 days
  • File an exception report to EPA region if receipt copy is
    not received In 45 days
  • File an annual report no later than March 1 of each year
                      Table 3
           3003 Standards for Transporters

    Must have an EPA identification number
    Signs generator's copy of manifest
    Must deliver waste to designated disposal site and receive
    signed copy of manifest
    Can accept only properly packaged wastes
    Is responsible for cleaning up any waste discharge or spill
                                                     49

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                       Table 4
           3010 Preliminary Notification of
              Hazardous Waste Activity

    All persons engaging in hazardous waste—management
    activities must notify EPA  or states having authorized
    hazardous waste permit programs
    Notification  package will be  mailed to about 350,000
    organizations already identified
    Notification forms must be received by EPA within 90 days
    of promulgation of standards for generators
    Failure to receive notification package does not release
    obligation to notify EPA
                      Table 5
  Schedule for Promulgation of Remaining Legislation

   April         3001    Identification and Listing
   February     3002    Generator Standards
   February     3003    Transporter Standards
   April/Fall     3004    Facility Standards
   April         3005    Permit Standards
   April         3006    State Authorization Standards
   February     3010    Notification Process
the EPA regional office. The other major responsibility is
the submission of an annual report to EPA by March 1
which must report all activities related to the shipping of
hazardous wastes.
  Let's now turn to what was the Section 3003-standards
for the transporters. (Table 3)
  Like the generators,  each transporter of hazardous
waste must also have an EPA identification number. The
transporter forms a part of the link in the "cradle to the
grave" control which is initiated by the manifest filled out
by the generator.  When picking up hazardous materials
for  transport,  the  transporter signs the copy  of the
manifest  which is  retained  by the generator.  He is
responsible for delivering the waste to the disposal site
designated on the manifest, and must receive a signed
copy  of the manifest when he delivers the waste to the
disposal  site.  The transporter is required to maintain
copies of these manifests in his files for a period of three
years. If more than one transporter is involved, generally
an additional copy of the manifest must be prepared by
the  generator  for each additional transporter. The first
transporter must  obtain a signed copy of the manifest
from  the second transporter. There are  some  special
provisions for hazardous materials delivered by rail or
water, so-called bulk  shipment.  In these instances,  a
standard  waybill or other shipping document which
contains all of the manifest information except EPA
identification number is considered satisfactory for bulk
transfers between shippers.
  As  I mentioned earlier, the packaging, labeling, and
placarding of the hazardous wastes must be performed in
accordance with DOT regulations. It is the responsibility
of the transporter  to  accept only properly packaged
wastes.
  Another item of importance to the transporter is that
the  transporter is  responsible for reporting and cleaning
up any spilled wastes.
  The disposal site operator is responsible for mailing a
copy  of the final  manifest verifying that the waste was
disposed of properly back to the  generator. The  only
exception to this  would be when hazardous wastes are
being shipped outside the country. When waste leaves the
United States, it is the responsibility of the transporter to
return to the generator  a copy signed by the exporter.
  Basically, other than the new manifest system, the
transporters will be subject to the same DOT regulations
that are currently in effect.
  The last section  for  which regulations  have  been
promulgated   are   those  relating  to  preliminary
notification of hazardous waste activity. (Table 4)
  The  law  requires  that  all  persons  engaging  in
hazardous waste management activity notify EPA. This
is not really any different than what took place in the
control  of  water pollution several years ago when the
permit  program  required notification.  EPA  will  be
sending out notification packages to about three hundred
fifty thousand (350,000) organizations which potentially
handle hazardous wastes and will need to file notification
forms; these notification forms must be received by EPA
within 90 days of  promulgation of the RCRA Section
3001  regulations  which  define  what are hazardous
wastes.  As  I mentioned earlier, the 3001 regulations are
scheduled to be promulgated on April 30.
  The failure to receive a notification package does not
release anyone from the obligation to  notify EPA. The
notification package is being mailed out as help to those
who we feel probably should be filing notifications.
  In the event that a disposal, treatment, or storage
facility does not provide notification, then it will become
ineligible for interim status pending issuance of a permit.
Without interim status or a permit,  a facility cannot
legally dispose, treat, or store hazardous  wastes. Once
you have  filed your  notification  you will receive a
verification from  EPA which will contain your EPA
identification number.
  There is  a tremendous  amount of interest about the
quantity of hazardous wastes you must generate before it
is required  that you apply for an identification number.
The Section 3001 proposed regulations had a lower limit
on  size, and we received many comments on this issue.
There is another question about the timing. Suppose you
have stopped handling hazardous waste.  In that event
you would not be required to file the notification. The
rule for this is any hazardous wastes  handled during the
3-month period immediately prior to  the date  of filing
must be included.
  The details of the form and the mailing address  for
receipt  of notification are all included in the handout
which was  released February 26, 1980. There are several
copies  available,    I  believe,  from  the  American
Electroplating Society or  your local EPA office.
  This completes my discussion on the regulations which
have been promulgated to date. As I mentioned earlier, a
very tight schedule is set for  the remaining regulations.
(Table 5).
  The two  key sections which will be of great importance
to  you  and  which  you should watch for closely  are
Section 3001,  which will define  what are hazardous
wastes,  and Section 3004,  which  sets standards  for
disposal of the wastes. The permitting process  (Section
3005), of course will also  be of great interest.
                                                      50

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         Report  on  the Results of the  AES/EPA
                Sludge Characterization  Project
                                        Kenneth R. Coulter*
   The disposal of waste treatment sludges has become of
 major concern to the metal finishing industry. This fact
 became evident at the first of the EPA/AES Conferences
 in Orlando, Florida in January 1978.
   In many areas of North America, due to  the lack of
 knowledge and understanding of the behaviour of these
 sludges in landfill sites, disposal had become extremely
 expensive, and, in fact, a virtual impossibility in many
 instances.
   The problems associated with sludge disposal became
 exacerbated  with the introduction by the  EPA of a
 proposed test method, under the Resource Conservation
 and Recovery Act. This test was designed in such a way as
 to simulate the conditions under which different types of
 solid  waste would behave, in conjunction with  the co-
 disposal of organic wastes, such as may be  found in a
 sanitary landfill.
   The test proposed by the EPA  calls for filtering or
 centrifuging the sludge, and then agitating the remaining
 solid   material  for   twenty-four  hours, with  a
 predetermined  amount of water. This is maintained at a
 pH of 5, using acetic acid. The resultant extract is mixed
 with the original filtrate from the original sample, and the
 concentrations of various materials are compared to the
 limitations for these materials as prescribed by the EPA.
 These concentrations  are generally established at ten
 times  the drinking water standard.
   The materials of  concern to the  metal finishing
 industry  with  the proposed  limitations are shown in
 Table I.
                    TABLE I
            PROPOSED HAZARD LIMIT
             Chromium
             Cadmium
             Lead
             Arsenic
             Mercury
             Silver
mg/1

 0.5
 0.1
 0.5
 0.5
 0.02
 0.5
*Kenneth R. Coulter, P. Eng.
 21 Bellehaven Crescent
 Scarborough, Ontario M1M1H2
  Solid wastes that yielded results above the proposed
limitations, would  require a  manifest system, and
disposal must be made to an approved facility.  While
these  facilities are  not yet determined or generally
available at present, it is possible that they would include
some  combination  of fixation,  landfill lining, and
leachate collecting and treatment.
  So  obvious were the consequences of these added
burdens that discussions ensued between the EPA and
the  AES, with a view  to  reconciling the behavior  of
electroplating waste sludges under the EPA extractions
procedure, with their behavior under field conditions.
  The proposal for a co-operative agreement evolved
during 1978  and the final draft was presented at the
second EPA/AES  Conference  in  February  1979.
Approval of the funding of 95% of the program by EPA
came in March 1979, and the Task Force appointed by
the  board of directors of AES began its work with the
author as technical director.
  The  Task  Force  members  were  Doug  Thomas,
chairman, Fred Steward, Irving Ireland, Richard Grain,
and George O'Connor.
  Howard Schumacher, the executive director of AES
was also appointed program co-ordinator, and Centec
Corporation  of  11800  Sunrise  Valley Drive, Reston,
Virginia was chosen as  the engineering and laboratory
sub-contractor.
  The method chosen by the Task Force called for the
selection of twelve sludge sources that represented the
spectrum of the metal finishing industry. These were to be
subjected  to a series of tests.
Phase I was designed to:
• Characterize chemically and physically the solid and
  liquid portions of the sludges.
• Determine the effect of pH on results of the EPA
  extraction procedure  (EP).
• Determine the effect of interstitial water, (i.e. water in
  the sludge) on the EP results.
• Determine the effect of sludge aging on EP results.

Phase II was designed to:
• Simulate more closely a segregated landfill containing
  hydroxide sludges, where there would not be severe
  agitation or exposure to low pH using a dynamic
  laboratory procedure.

Phase III:
• was a field test, where soil samples were taken below a
  sludge bed that had been in use for ten-twelve years at
  the site of one of the plants from which current sludge
  samples were taken. (Plant #11).
                                                 51

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Plant
IA
2A
3A
4A
5A
6A
7A
8A
9A

10A
11A
12A


% Solids
11
6
3
7
17
34
15
29
39

24
19
23
TABLE II
PLANT DESCRIPTION
Primary Plating Process
Segregated Zn
Segregated Cd
Zinc Plating and Chromating
Cu-Ni-Cr on Zn
Al Anodizing
Ni-Cr on Steel
Multi-process Job Shop
Electroless Cu on Plastic, Acid Cu, Ni, Cr
Multi-process with Barrel or Vibratory
Finishing
Printed Circuits
Ni-Cr on Steel
Cd-Ni-Cu on Brass and Steel
  Phase I,  description  of the  experiments,  results,
conclusions, and recommendations are contained in the
Interim  Phase  I  Report,  which  was  submitted  in
September 1979.
  The complete report, under the title "Interim Phase I
Report, Electroplating Wastewater Sludge Characteriza-
tion" is available at no cost from John Lehman, EPA,
Office of Solid Waste (WH-565),  Washington,  D.C.
20460. A synopsis of this paper was published in Plating
and Surface Finishing.
  In the interest of time, I will touch on the highlights of
that report and its conclusions.
  Table II describes the plants sampled and the toxic
materials, as defined by the proposed RCRA regulations
that were present in the sludges as weight percentage of
the dry solids.
  Time  and   resources  did  not  permit   in-depth
engineering studies of the plants being sampled, but with
one exception,  sufficient data was obtained to describe
the nature of the treatment system and the volumes
involved.
  Figure 1 is a schematic of the extraction procedure.
  The experiments conducted  included:
  • Effect of pH on extraction.
  • Effect of volume of extraction water.
  • Reproducibility.
  • Effect of temperature.
Figure I. Extraction Apparatus

  • Comparison with ASTM extraction procedure.
  • Effect of sludge aging.
  • Total metal content.
  • Anion content.
  • X-ray diffraction.
  • Filtrate analysis and washing.
  • Filtration versus centrifuging.
  In  Table III, the results  of the execution  of the
extraction  procedure at  a maintained pH  of 5,  as
proposed by the EPA, and at four other pH's is shown.
       2.0
  mg/l
       1.0
       0.5
                            « Proposed Hazard Limit
                                             ACd
                 tCd
             I    I   i    I   I    I    I   I    I   I
             4      6      8      10     12     14

                             pH


Figure II. Changes in Cadmium Concentration with pH
TABLE III
EFFECT OF PH

Proposed Hazard Limit Metal
1 A (11% Solids)
2A (6% Solids)
3A (3% Solids)
4A (7% Solids)
5 A (17% Solids)
6A (34% Solids)
7A (15% Solids)
8A (29% Solids)
9A (36% Solids)
IDA (24% Solids)
11A (19% Solids)
12A (23% Solids)
Blanks, Ba, and Se were at or below detection


pH5
pH5
pH5
pH5
pH5
pH 5
pH 5
pH 5
pH5
pH 5
pH5
pH5
limits.
mg/l
0.5 Cr.
1.22
1.89
85.0
21.8
<0.01
25.4
0.24
400
0.32
0.12
4.22
4.85


0.1 Cd
0.23
126
6.00


<0.01
2.16

0.03

<0.01
263


0.5Pb
0.041
<0.001
0.009
0.038
<0.001
.001
.003
0.032
.010
0.88
0.004
0.031


0.5 As 0.02 Hg 0.5 Ag
0.073 <0.01
0.005 <0.01

.02

-------
mg/l
     40
     30
      20
      10

    0.05
    0.03
    0.01
                                              OCr
                                  10
                                          12
                                                 14
                           pH
Figure III. Changes In Chromium Concentration with pH

  Figures II and HI show the results in graph form for
typical plants  with significant cadmium and chromium
content.
  Table IV shows the effect of aging on the EP at three
months, compared with the original extraction.
  The conclusions that were reached concerning Phase I
were:
  •  EP is sensitive to pH.
  •  EP exaggerates the leachability of the sludge since it
     includes the effect of metal levels in interstitial (i.e.
     associated) water.
  •  Aging greatly decreases leachability.
                       TABLE IV
             EFFECT OF AGING SLUDGE
                    EP Results mg/l
                        Plant 7A
   pH 5 Fresh
       Aged (3 months)

   pH 7 Fresh
       Aged (3 months)
 Cd

2.16
0.30
0.04
0.01
 Pb

0.003
0.002

0.005
0.001
 Cr

 0.24
<0.05

 0.50
 0.15
   The interstitial water  is simply the supernatant and
entrapped   water  mixed   with  the  sludge.  Its
concentrations of metallic ions will  be essentially the
same as the plant's effluent as discharged to a water body
or a municipal sewer. It is possible that a plant could be
meeting an effluent discharge regulation, but would be
beyond the proposed hazard limit for sludges, because of
the metal content of the interstitial water alone. This
point is further  developed in the interim report, and I
would recommend it to your attention.
  Surprisingly,  and  in spite of the presence of some
interstitial  water,  Plants #5  and #9  passed the very
aggressive EP test.
  When the distorting effect of the interstitial water is
removed, the sludge then behaves in the extraction as one
would expect from the laws of chemistry.
  Using the results of Phase I as a guide, we were able to
enter Phase II work,  knowing much of the nature of the
sludges with which we were dealing.
  Phase II was the dyanamic testing designed to simulate
segregated landfill conditions.
                                                                                          5 gal DEIONIZED
                                                                                             WATER
                     DYNAMIC TESTING APPARATUS

Figure IV

  A reduced number of plant sludges was used for this
Phase, in order to maximize the number of experiments.
Plants 4, 5, 6, 8, 11, and 12 were chosen as being widely
representative of those with  hazardous  materials, as
defined by RCRA.
  The complete description of the procedure will appear
in the final report, which will be available this summer.
However,  the  schematic  drawing  in  Figure  IV
encompasses some pertinent data.
  Samples are poured  into weighed Buchner funnels
seated with filter paper. D.I. water is fed from a container
above  the filter.  A vacuum is applied to remove the
interstitial waters and these are then added back to the
top of the sample cake, so that it can be leached through
at a more normal rate.
  The leachates were analyzed on days 1, 2,  3, 5, 7, and
every seventh day thereafter for the metals expected to be
most predominant.
                            fig/a
                                0.5
                                                    • Plant 4A Chromium
                                                    Q Plant 12A Chromium
                                                    A Plant 12A Cadmium
                                                    14       21
                                                    DAYS LEACHED

                           Figure V. Dynamic Testing of Chromium & Cadmium Versus Days
                           Leached.
                                                      53

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TABLE V
PHASE II DYNAMIC LEACHING
Days Leached
Chromium mg/1
Plant Sample
Code
4A
5A
6A
8A
11A
12A

12A
* = <0.05
EP Test
Results
21.8
<.01
184.0
400.0
4.2
4.6

268


/
1.01
<0.05
<0.05
*
<0.05
0.34

0.24


2
0.14
<0.05
<0.05
*
0.05
0.21
Cadmium
0.18


3
0.12
0.06
<0.05
*
*
0.15
mg/1
0.16


5
0.12
0.06
<0.05
*
*
0.12

0.12


7
0.08
0.07
<0.05
*
*
<0.05

0.11


14
0.08
0.05
<0.05
*
*
0.07

0.09


21
0.08
<0.05
<0.05
*
*
0.05

0.09

  The results are shown in Table V.
  Figures  V  and  VI show  graphically and  rather
dramatically how quickly the interstitial water is flushed
through, and how little material is leached thereafter.
  The flow rates involved were approximately equal to
one half inch of rain per day for the entire thirty-five days
of the test.
  It  will be  noted that these leaching results  are
approximately the same as the results obtained from the
extraction made in Phase I at a pH of 7.
  Although nickel is not on the list of hazardous metals
as defined by RCRA, we have included it to show that it
behaves in a similar manner.
  The conclusions that may be drawn from the Phase II
work are:
  • Dynamic  tests  show drastically reduced levels of
    metal concentrations in  the leachate, compared to
    the EP.
  • This work confirms  the indications from Phase I
    that interstitial  water can be the major contributor
    to metals in leachate.
  I  would like to repeat that this  interstitial water is
essentially the same as the effluent and is a very small
percentage of the total metal content of the sludge. A
calculation of this percentage is in  the  Phase I report.
  Also established is the fact that for a sludge source to
apply stringent dewatering to his settled solids in order to
pass an EP test would not, indeed, make a contribution
toward improving the environment. The decision as to
how much to dewater should be based on the pragmatic
 /U9/9
1.0


0.8


0.6


0.4


0.2
                                    O Plant 5A
          12357      14      21      28

                        DAYS LEACHED

Figure VI. EPA-AES Nickel (Nl) Leachate vs Days Leached
                                             35
economics of shipping and handling, space limitations,
etc.
   While building the information bases in Phase I and II,
we had largely exhausted our available funds. However,
we did manage to have sufficient means for one field trip
to the location of Plant #11.
   This plant had  begun to dispose of metal finishing
waste  treatment sludges twelve years  ago in a pond
created by  excavation  on their property.  This pond
became dormant six  years ago  and a new pond  was
developed some  miles away that was dug to a limestone
base.
   In order to gain access to the soil under the pond, (there
was actually two ponds), the company pumped it out just
before our arrival. Samples were taken at two depths of
soil  below  the  interface and  at  the interface. A
background sample was taken from the soil at a distance
sixty feet from the pond.
   During the pumping-out procedure, the suction end of
the hose kept plugging with bullfrog tadpoles. Some of
these hundreds  of tadpoles were  still alive when we
arrived.
   Samples were also  taken from the newer limestone
based pond and  from  a drainage ditch at a point thirty-
five feet below the pond.
   The results of these  samplings are shown in Table VI.
Each sample, except the water sample, was subjected to
the EP test at a pH  of 5, and some were  completely
digested and analyzed.
  While this Phase III  work was limited, (more sampling
work should  be  done in the field)  there was no  result
which disproved  the outcome of Phases I and II, but the
evidence was, rather, to the contrary. There appears to be
no harmful effect on  the  environment when  metal
hydroxide sludges are disposed of in a segregated landfill.
  The landfill need not be elaborately prepared, such as
having lining or limestone base, and without the necessity
of paying  for  expensive  fixation  treatment. This
information, in turn, will permit more flexibility in the
location of these landfill sites, which could also receive
other sludges  such as fly ash, without  disturbing  the
plating waste sludges.
  Some unfinished work, however, still remains. There is
always the possibility that a malfunction  of a  waste
treatment system may produce a sludge that would not be
compatible with other  sludges in a segregated landfill. It
                                                     54

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PHASE


Plant Sample Code
Leachate
Surface Sludge
Subsurface Sludge
Older Subsurface Sludge


1 1" Below Sludge
17" Below Sludge
Sludge
Background Soil
TABLE VI
III — PLANT
New Land Fill
mg/1
Ag
0.01
0.02
0.01
<0.01
Old Land Fill
mg/1
0.03
0.02
0.19
<0.01

SITE II


As
0.004
0.006
0.005
0.002


0.022
0.011
0.002
0.004
(Samples were also analyzed for Ba, Cd, Pb and Se.
detection limits.)






Cr
<0.05
3.58
4.37
3.35


<0.05
<0.05
0.09
<0.05
All were below

     is important that the sludge generator knows this before
     he ships that  particular sludge,  and for the landfill
     operator to know that he is receiving a "safe" sludge.
       To  help  minimize  this potential  problem and  to
     simplify test procedures, future work  should include:
       •  Development of a quick test which would separate
         the effects   of  interstitial   water  from  sludge
         teachability,  and  would  confirm   the  sludge's
         suitability for disposal in a segregated landfill.
       •  Obtaining data which would provide guidance to the
         plater which will ensure  him that his sludge will be
         suitable for disposal in a segregated landfill.
       Much of the success of the project has resulted from the
     very high level  of technical direction received  from the
     Task Force and  the very professional performance of
     Centec Corporation and its personnel.
       The Task Force that volunteered its time, put more of
     it into  this  project than originally was anticipated. It
     always responded to the requests of the chairman, Doug
     Thomas, Howard Schumacher, and myself.
       The  co-operation  of  the Metals and  Inorganic
     Chemicals Branch of EPA's  Industrial Environmental
     Research Laboratory  in  Cincinnati,  and   George
     Thompson, and Fred Craig in particular were vital to the
     completion of this work.
55

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            Solids  Removal  and Concentration
                                          Richard W. Grain*
  Over the next several years it can be expected that the
matter of sludge disposal will be somewhat unsettled
until  a  national  understanding  is  reached.  That
agreement could be as simple as mutual endorsement of
one region's existing regulations or as complicated as
adoption of "numbers"  by the federal authorities. The
latter  with  the tedious and  expensive promulgation,
discussion, possible litigation, and subsequent adoption
phases to follow, as  we've seen in the  electroplating
pretreatment (heavy metal) regulations.
  Whatever the result, most legal authorities agree that if
one set of regulations causes you to remove heavy metal
sludges; other authorities must provide or endorse a place
to put them.
  Making the metallic  hydroxides and  other sludges
resulting from metal finishing "PRESENTABLE" to the
receiving authority or a private disposal site is the subject
of this paper.
  Properly  neutralized  and  conditioned,  thickened
and/or dewatered  sludge has been shown (1) to  be
relatively inert. Surprising to  some, the technology for
accomplishing this has been well known for over 25 years.
(2-4)
  Therefore, we will examine in detail the current state of
the  art of concentrating sludges to enable them  to be
handled and transported as inexpensively as possible
and disposed of at approved sites.
  Sludge concentration  is usually known as thickening
and discussed in those  terms up to the 15%/wt.  level.
Beyond 15% we refer  to a dewatered sludge (5).

COAGULATION AND FLOCCULATION
  Before investigating the actual mechanical  methods
used to dewater this type sludge, we will first discuss the
various  aids  to  coagulation  and  flocculation  which
hasten mechanical separation.
  Coagulation is the conversion by a simple electrolyte of
colloidal and dispersed particles into a small visible floe.
Inorganic coagulatants are simple electrolytes which are
water soluble, low molecular weight  inorganic acids,
bases, or salts of iron,  aluminum and calcium. Examples
being ferrous sulfate, alum, or lime.
  Flocculation  is  further agglomerated  by  a
polyelectrolyte of the small slowly  settling floe formed
during coagulation into a large, rapidly settling floe.
Organic flocculents are water soluble, high molecular
weight polymers. These  can be either anionic or cationic
•Richard W. Grain
 Industrial Filter & Pump Mfg. Co.
 5900 Ogden Avenue, Cicero, IL 60650
in nature and should be added in small amounts (such as
0.2-1 mg/1). However, polymeric flocculent aids are best
used when tested at the job site by a technical service
representative of one of the many supply companies.
  It is extremely important in coagulation, flocculation,
settling, and dewatering that the floe be properly formed
and, once formed, treated "tenderly".
  When  heavy metal  bearing  effluents  have  been
chemically treated to render them less or non-toxic, they
must ultimately have a final pH adjustment prior to final
liquid/solids separation. As sensed by automatic pH
control, the optimum pH for the great bulk of mixed
metal finishing wastes is 8.3. (5)
  Lime and/ or caustic should be added into the vortex of
the  mixer of a  tank type final neutralization. Mixing
should  be slow so as to promote coagulation created by
this  inorganic  acid. Organic  (polymeric) flocculation
should  be introduced at the exit of the final neutralization
basin. Such introduction should be made in a quiescent
zone as a part of, or prior to, a clarifier.
  Whatever method is ultimately selected to dewater this
type of sludge, certainly lab tests, if not actual on site pilot
systems should be used to determine cycle lengths, cake
dryness, and ease of handling.


EQUIPMENT AND PROCESSES (5)
  Numerous  processes   and  equipment  types  are
available for sludge thickening and dewatering. Criteria
for  selecting one  or  more techniques  depend on  the
characteristics and the amount of sludge to be processed,
capital and operating funds  available, size and type of
treatment plant, cognizant regulatory requirements, and
the final disposition.
  Terms used in describing sludge handling requirements
and equipment are defined in Table I. The general types
                     TABLE I
              TERMS—DESCRIBING
         SLUDGE HANDLING EQUIPMENT

   • Solids Loading—Percent Solids in Stream
   • Cake Cone.—°/o Solids by Weight In the Thickened or
        Dewatered Sludge
   • Capacity—Flow Rale of Wastewater or Volume/Cycle -
        Time of Batch Devices
   • Particle Size—Diameter of Particles
   • Solids Recovery or Solids Retention—% of Solids in the
        Input Stream Removed in the Thickening Process.
   • Yield—Output of Filter in Pounds of Solids per Square
        Foot of Filter per Hour
                                                   56

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                                               TABLE II

                  CLASSES OF  EQUIPMENT AVAILABLE FOR  THICKENING AND DEWATERING
TYPE
STIRRED GRAVITY
AIR FLOTATION
CENTRIFUGES
DISC
SCROLL
-BASKET
FILTERS
VACUUM DRUM
VACUUM BELT
PRESSURE
BELT
DUAL CELL GRAVITY
FEED
RATE
(GPM)
10-3000
10-10,000
25-300
5-300
10-60
0-250
1-50
10-250
5-200
10-500
SOLIDS
LOADING
(% SOLIDS)
	

0.2-1
0.5-15
1-10
8-10
5-10
2-5
4-6
0.5-5
PARTICLE
SIZE
(MICRONS)
~~~

1'tO5
I-106
1-106
5-10'
1-102
1-I02
10-102

SOLIDS
RETENT
(% SOLIDS)
95-98
92-98
90-95
60-95
90-95
50-99
75-90
95-99
95-99
90-98
OUTPUT
CAKE
CONC
RANGE
(It, SOLIDS)
5-10
5-10
5-10
20-45
5-25
20-40
15-25
20-50
20-35
10-20
CAP
INVEST
($1000)
14-140
28 - 560
28-196
28-280
28-168
7-42
21-105
7-700
14-168

APPLICATIONS
PRIMARY SECONDARY
PRIMARY AND SECONDARY,
METALLIC, CHEMICAL
WASTE-ACTIVATED, LIME ,
FLOCCULATED ALUM
WASTE -ACTIVATED
RAW OR DIGESTED PRI -
MARY OR SECONDARY,
ALUM , LIME
WASTE - ACTIVATED , LIME ,
ALUM
DIGESTED PRIMARY OR
SECONDARY
INDUSTRIAL
ALUM , WASTE -ACTIVATED,
HYDROXIDE
SECONDARY BIOLOGICAL
PRIMARY AND SECONDARY
INDUSTRIAL
PRIMARY, SECONDARY,
INDUSTRIAL , TRICKUNG
FILTER

INDUSTRIAL
HYDROXIDE
CHEMICALLY PRECIPITATED
CLARIFIER OVERFLOWS
MUNICIPAL , INDUSTRIAL ,
CHEMICAL
PETROCHEMICAL , INDUSTRIAL
METAL HYDROXIDE
of equipment available for thickening and dewatering are
shown in Table II, with indications of performance which
can be achieved. In general, each class of equipment and
device will  have advantages and  disadvantages for a
specific application. Your application and the equipment
available can often be matched by answering the typical
questions which should be asked as shown in Table III.
  The method or  device used to achieve your desired
result may be one of the following (7):

A. Lagooning/Drying Beds
  Lagooning as a method is no longer widely accepted,
although many  lagoons still exist. Usually, a 4-17 day
holding capacity is required to achieve  proper settling.
Such space allocations in populated areas are becoming
prohibitive.
  Further, two basins, 3-5 feet deep, are required so that
one can dry while the other is in use. Depending on the
evaporation rate in that region, this could take 6 months
to 2 years.  The ground water  can be contaminated by
insufficient lagoon lining (natural or artificial).
  At the end of the  drying period, they usually only
achieve a 4-10%/wt. solids. Further dewatering can be
achieved by spreading this sludge over a coarse bed of
sand, coal, or gravel. 25-40%/wt. solids can be achieved
in this way under optimum climatic conditions.

B. Clarifiers
  The discussion of clarifiers (8-12) will be divided into
four  categories,  namely;   gravity,  stirred   gravity,
dissolved air flotation (DAF), and rapid settlers.
  Figure #1  illustrates a conventional  gravity settler.
Typically these units can thicken from 2 to 10%/wt. With
                      TABLE III
   QUESTIONS TYPICALLY ASKED IN MATCHING
       APPLICATIONS REQUIREMENTS WITH
             EQUIPMENT PARAMETERS
   • Operational Variables Affect Equipment Performance

   • Throughput, and Feed Rate vs. Solids Loading
   • Pretreatment of the Sludge Needed to Reduce Moisture
        so that Input Solids Loading is Acceptable
   • Effectiveness - Relationship Between Solids Recovery
        and % Solids in Output Cake
   • Cost of  Purchase,  Including  Engineering  and
        Installation
   • Cost of Operation,  Including Chemicals,  Labor,
        Maintenance,  and Replacement of Expendable
        Parts
these, a sludge blanket is formed by proper sizing and
flow distribution which is extremely important. So, too,
is  the sludge withdrawal rate, so as not to  upset the
system,  creating high TSS discharges. Such units are
relatively inexpensive but do occupy considerable floor
space. Figure #2 points to design parameters affecting
clarifier design.
  The next figure (#3) illustrates a conventional stirred
clarifier.  These  are open  cylindrical  tanks  with the
influent feed normally at the center and with some means
for distributing the sludge radially. The solids are drawn
                                                     57

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                                                                DRIVE HEAD
                                                                   FEE DWELL
                                          LIFTING  DEV1CF

                                         VERTICAL SHAFT
                                                             CENTER SCRAPER
                                                                                                      RAKF ARV
                                              RAKE BLADES
                                          UNDERFLOW DISCHARGF CONF
                                                              CONVENTIONAL TYPE THICKENER
           Figure 1—Conventional Gravity Setter.
                     Figure 4—Schematic Diagram of Solids Contact Clarlflers.
         PARAMETERS OF CONCERN IN THE
              DESIGN OF A CLARIFIER
    INLET
    ZONE

 OUTLET
t ZONE

A



—
*

-



, i
EFFECTIVE
SETTLING
ZONE
i * i



, ,
*


—
SOLIDS REMOVAL ZONE
y




             FUNCTIONAL ZONES IN AN IDEALIZED
                  SEDIMENTATION BASIN
                      Figure 2.
                  Figure 5—Schematic Diagram of Horizontal Clarifying Equipment.
           Figure 3—Conventional Stirred Clarlfler
                             Figure 6—Dissolved Air Flotation Unit
off at the center (figure #4) and with proper conditioning
can reach 10% levels. The effluent could still contain up
to 50 ppm TSS.
   Horizontal clarifiers  are  also  common. Figure #5
illustrates a typical unit. Note  should be taken of the
several mechanical methods  used  to slow agitation and
promote flocculent growth. Any significant agitation or
introduction  of  air  bubbles will destroy  the  sludge
settlement.
  Another type of unit (DAF), in fact, takes advantage of
this  phenomenon.  Dissolved air flotation units (figure
#6) are the reverse of the clarifiers described  thus far.
                They are generally open tanks into which a gas or air is
                bubbled. The sludge particles become attached to the fine
                bubbles and float to the surface where they are skimmed
                off. The  underflow  is the  "clear"  effluent.  Factors
                affecting the effectiveness of these units are particle size,
                specific gravity, air to solids ratio, and the removal (skim)
                mechanism.
                  Rapid settlers  may be tube  type,  plate,  and  other
                laminar (lamella) settlers. These units are said (10) to
                require only 1 /4th to  1 / 10th the floor space required for
                conventional gravity and stirred gravity types. They use
                the design  of angular  tubes  or plates which  have
                extremely high surface areas and only 3/4 to 2" drop of
                                                       58

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solids in angular (usually 45°) tubes or parallel plates
(figures #7 and #8). The units produce a sludge of up to
10% and an overflow of 10-30 ppm TSS. They are often
installed inside and are easily maintained. The principal
disadvantage is said to be a blocking of the channels or
tubes, if there is an improper sludge draw-off.
   Laminar  flow  packs  can  even be  installed  in
EXISTING  conventional   clarifiers  to  enhance   the
effectiveness (figure #9) or increase their capacity without
enlarging them.

C. Centrifuges (5, 6)
  These units are normally very compact. They are the
first units to be discussed which DEWATER rather than
thicken  according to our earlier definition.  They  are
highly influenced by the influent rate and percent solids
in the feed. They can typically dewater to  15%.  The
centrate almost always must be recycled as it contains
500-1,000 ppm TSS.  Centrifuges  have a high power
consumption and some history of maintenance problems
due to their high rotation rate.  Slower speed units are
being developed and  becoming popular. Figure #10
illustrate a bowl centrifuge.

D. Vacuum Filters (5, 6, 12)
  Rotary drum vacuum filters have been used for many
years in all facets of sludge dewatering. However, unless
they are  precoated  with  a  filteraid  material,  they
normally require that the influent sludge be thickened (by
one of the methods described in  "B" above.) Figure #11
illustrates a rotary vacuum filter. The submergence of the
drums  is normally in the  30% range. Therefore, the
efficiency of these units is low, but the fact that they are
continuous is a very favorable offset. These units are also
relatively energy intensive  and are said to potentially
have problems associated with maintaining a vacuum.
  The rotary  vacs dewater to 25-35% with the filtrate in
the 100-700 ppm range for those who do not use precoat.
                               Eflluent
                          	Heavy
                             Components
                    UKttU
                                                              TUBE SETTLERS IN EXISTING CLARIFIER
           Figure 7—Schematic - Tilted Plate Clarlfler.
                       Figure 9.
         Figure 8—Production Unit - Tilted Plate Clarlfler.
               Figure 10—A Bowl Centrifuge.
                                                     59

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              Figure 11—Rotary Vacuum Unit.
                  Figure 12—Belt Filter.
                       ^ IDI   r4—i
                       nisi)   i ' I
             Figure 13—Plate/Frame Press Filter.
             Figure 14—Typical Plate/Frame Filter.
E. Belt Filters (6, 12)
  These units (figure #12) distribute gravity flow and
through a series of belts allow for the  drain off of the
liquid phase. A second stage employs  pressure rollers.
The  units are  continuous and relatively inexpensive.
They do normally require conditioning chemicals or
prior thickening in order to produce 15-20%/wt. solids.
The  belt is washed for reuse on a continuous basis to
inhibit blinding.  The filtrate contains 500-2,000 ppm
TSS. Design rates are 2-8 GPM/sq. ft.

F. Filter Presses (5, 6,  8, 13)
  Filter presses have been widely used in the chemical
process  industries since the 1920's. Although there are
many configuration variations,  a plate/frame  press
consists of a number of vertical plates which are held
rigidly in  a form to ensure alignment. The trays are
recessed so  that  when pressed between the fixed and
moving  ends of the head, they form a  hollow chamber
(figure #13). The  inside of each hollow chamber is lined
with a filter cloth. Sludge is pumped through holes in
each chamber. The drainage member behind each cloth
allows for passage of a clean filtrate and deposition of the
sludge on  the cloth.  Dewatering takes place as the
influent sludge reaches high pressure (100-200 PSIG).
Cake is '/2 to  1" thick and 40-50%/wt.  solids can be
expected. The filtrate clarity is 0-10 ppm TSS depending
on whether the unit is first precoated or not. Figures #14
illustrates a typical P/F press.
  Another press variation is the conventional pressure
leaf type filter unit, with compressive diaphragms or
membranes. These units operate at much lower pressures
(approximately 50-70 PSIG).
  Both  conventional  plate  and  frame  and  the
compressive diaphragms have received wide acceptance
as the devices offering the driest possible cake. Flow rates
are I/10th to I/20th GPM/ft2.

G. Pressure Leaf Precoated Filters (3, 5, 6)
  These pressure leaf units operate at much lower (up to
40 PSIG) pressures  then plate and frame presses (up to
200  PSIG).  Normally,  they  use  a  precoat  on  a
conventional leaf. Rates  are typically I/4th to I/10th
GPM/ft2. The cakes (figure #15) are 35-40%/wt. and the
filtrate the best of any dewatering  device (0-5  ppm).
Relatively large units  are  required  for the DIRECT
filtration of metallic hydroxides (example  . . . 1,000 ft.2
for 100 GPM). However, no  other devices are needed.
There  is  no  requirement for  thickening ahead  or
polishing behind these units.
  Other  pressure  leaf units  (figure #16) will accept
prethickened sludge at rates of 1 /20th GPM/ft.2 or direct
filtration at 1 / 4th GPM/ft2 producing a 20% dry solids in
either case on an automatic basis.

H. Fixants and Incineration
   These two methods of making dewatered  sludge
"PRESENTABLE" share one thing in common. The
                                                     60

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             Figure 15—Pressure Leaf Filter Cake.
                                                                      Figure 16—Pressure Leaf Filter.
dryer the dewatered cake fed to the fixant or incinerator,
the more economical the method.
  Chemical fixant processes have been evident for about
10 years (13, 14). Most common processes incorporate
the addition of a silicate compound in order to produce a
concrete like product. The feed to these processes could
be anywhere from 2% (clarifier underflow) to 40% (filter
press cake).
  The economics  of these  methods have yet  to  be
clarified for metal finishing wastes. However, more and
more interest has been shown by the industry and general
public.
  Incinerators too have been used (though not widely)
for  over  10 years as a  method  of making sludge
"PRESENTABLE." Multiple hearth and rotary hearth
incinerators are in common use. A study (15) shows the
most economical sludge to be handled  is that from a
pressure  leaf or plate and frame press. However,  an
evaluation  of these, filters, belt presses, centrifuge, and
vacuum filters indicate they are also said to be the most
expensive method of dewatering.
  We  have painted  the  subject of  making  metallic
hydroxides presentable with a  rather "broad brush."
From drying beds on the low  end, to incinerated  or
chemically "fixed" sludge (which was first thickened and
later dewatered ahead of it) on the high end.
  The question which ultimately must be answered is...
in what condition will MY sludge be accepted and how
can I get it to that point at the least overall cost? The
methods or combinations described here can achieve any
requirement which you will be given. Which method you
use over all, and over the next few years can ONL Y be
determined  by your  regulatory requirements;  then
examined in detail by your supplier  and/or consultant.


ACKNOWLEDGMENTS
  In the  preparation  of this  paper,  15 companies well
known  in  the industry were asked  to contribute
information and/or slides.
  The  following  are  acknowledged  with  thanks
for contributing to the technical education of the society.
  1.  Parkson Inc., Ft. Lauderdale, FL
  2.  ERC/Lancy,  Div.  of  Dart Environment  And
     Services Co., Zelienople, PA.
  3.  Dorr-Oliver, Inc., Stamford, CT.
  4.  Komline-Sanderson Engineering Corp., Peapack,
     NJ.
  5.  Haviland Products, Inc., Grand Rapids, MI.
  6.  D. R. Sperry, Batavia, IL
  7.  Industrial Filter & Pump Mfg. Co.,  Cicero,  IL
REFERENCES
 1. Minor, Paul S., Procko, Andrew, McCarthy, James
   A.  & Meredith, John W., "Determination Of The
   Leaching Properties Of  Metal  Finishing Waste
   Treatment  Sludges,"  SUR/FIN  '80,   AES
   Convention, Milwaukee, WI (June 22 - 26), 1980.
2. Crain, R. W., "Sludge - By Any Other Name It's Still
   A  Problem,"  Enviroscope,  Plating  and Surface
   Finishing, (May 1977), p.  44-45.
3. Zievers, J. F. & Riley, C. W., "Handling Waste
   Sludges," Plating, (August 1959).
4. Haviland, Joseph M., "What To Do About Sludge,"
   Products Finishing, (Febr. 1980),  p. 56-59.
5. "Selecting  Sludge  Thickening  And   Dewatering
   Equipment,"  Pollution Equipment News, (Febr.
   1976), p.  41-47.
6. Daniels, Dr. Stacy L., Dow Chemical USA,  Mid-
   land, MI "Product Development  and  Stewardship
   of Flocculants for Water  and Wastewater Treat-
   ment", American Chemical Society, San Francisco,
   CA, (Aug. 31,  1976).
7. Crain, R. W., "Sludge Dewatering .  . . Settling,
   Centrifugation or  Filtration," presented  at  IPC
   Water Pollution  Control Workshop, Chicago, IL,
   (May 23-24, 1978).
8. "Clarifying  Metal   Finishing  Wastewater,"
   ERC/ Lancy, internal education paper and Technical
   Bulletin No. 6201 (1979).
                                                   61

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 9. Probstein, Ronald F., Hicks, R. Edwin, "Lamella      11.  Dorr-Oliver,  Inc.,  Stamford,  CT,  private
   Settlers:  A  New  Operating  Mode  for   High         communications (1980)
   Performance,"  Industrial  Water  Engineering,      12. Komline-Sanderson Bulletin No.  KSB  123-7090,
   (Jan/Feb. 1978), p. 6-8.                                  "Dissolved Air Flotation."
10. Cheremisinoff,  Nicholas  P.,  "Lamella  Gravity      13. Davy, Thomas E., "Handling Sludge Problems With
   Settler:  A  Compact  Clarifier,"   Pollution         Modern  Filter  Presses,"  Filtration  Engineering,
   Engineering, (March  1977), p. 33-35.                      (March/April 1973), Vol. 4, No. 2, p.  6-10.
                                                   62

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        Making Hazardous  Wastes Nonhazardous
                                        Robert B. Pojasek, Ph.D.*
 INTRODUCTION
   Once  a waste  is  designated  or declared to  be
 "hazardous"  under  the  Resource  Conservation  and
 Recovery Act (RCRA) it becomes subject to a myriad of
 rules  and regulations  promulgated  by  the U.  S.
 Environmental  Protection  Agency (EPA).   RCRA
 regulations require  strict control of hazardous wastes
 from "cradle-to-grave;" i.e., from generation,  through
 transportation, storage, treatment, and disposal. There is
 little doubt that these regulations will change the way
 industry does business. The cost of disposal will go up,
 the  financial impacts will be significant, the technical
 requirements will increase, and the paper work will grow.
 Under RCRA you will be required  to do the following:
   •  Provide  notification  if you produce "hazardous"
 wastes
   •  Provide  proper containerization for "hazardous"
 wastes
   •  Maintain complete records  of waste generation,
 handling and disposal
   •  Obtain   permits   for  treatment,  storage,
 transportation, and  disposal.
 To  make matters  worse,  the design  and operating
 requirements for "hazardous" waste disposal will serve to
 diminish the  already limited off-site capacity. Would it
 not  be great to convert  the hazardous waste into a
 nonhazardous material?

 THE CONCEPT
   EPA has chosen to use an elutriate test to determine
 whether toxic components can be leached from the waste.
 The analysis of the extract from an operationally defined
 procedure determines whether the waste is hazardous by
 the toxicity characteristic.  Separate testing must be done
 for ignitability, corrosivity, and reactivity. Now let us
 suppose that the waste is toxic according to the test and
 suppose that the  waste  were  incorporated  either
 chemically or physically  in an inert and monolithic
 matrix. EPA's protocol as proposed in the December  18,
 1978, Federal Register calls for the use of the structural
 integrity procedure on solidified wastes.
   The basis for the use of this procedure developed from
 EPA's concern that if these monolithic  solids do  not
 physically break down during disposal,  it would  be
 inappropriate to grind the waste into smaller particles
 than  is necessary for elutriate testing.  Certainly  the
 leaching characteristics for a divided waste will  be quite
 different from that of the waste in monolithic form. The
 structural integrity  procedure  was  designed  to be a
•Robert B. Pojasek, Ph.D
 289 New Boston Park
 Woburn, MA 01801
moderately severe approximation of the disintegration
which might be expected to occur if a solidified waste was
used  as  fill  or construction  material.  Under these
conditions crushing might occur from the passage  of
heavy equipment over the waste. After conducting this
test on the solidified waste, the intact solid, with  its
greatly reduced surface area, is extracted.  If the waste
passes the toxicity test requirements and does not have
the other characteristics listed above, it can be declared
nonhazardous. A Jess stringent set of regulations under
RCRA Subtitle D may be used for the solidified waste
handling. However, if the waste is "hazardous" prior to
solidification, a permit to treat hazardous waste will
probably be required.

SOLIDIFICATION PROCESSES
   A wide variety of commercial solidification processes
are available.  Many of the vendors have had specific
experience with wastes from this industry. A number of
references written  or edited by the  author  on  these
processes may be found at the end of this paper.
   The waste generator may choose to develop and use a
generic solidification procedure. This can be done  by
selecting the proper solidification agent and following the
conceptual flow outlined below. However, the industry
should realize that the  process  may require substantial
engineering and development costs to initiate. Many of
the vendors are already prepared to adapt their processes
to your wastes.
   Recently a number of processes have been developed
specifically to handle organic-contaminated inorganic
wastes and organic wastes with metals contamination.
These two cases had posed problems in the past thereby
effectively limiting solidification to  inorganic wastes.
Solidification has also  been used in conjunction with
incineration for organic wastes. This has been done by
solidifying the waste for ease of handling, incinerating the
waste for volume reduction, and resolidifying the ash.
Inorganic solidification processes have been used  to
solidify   the  toxic  ash  derived  from  conventional
incineration of organic wastes.
   There are typically five steps involved in solidification.
They are:  waste  collection,  waste  pretreatment,
solidification  agent addition, mixing/packaging, and
disposal. Each step is briefly discussed below.
   Waste Collection. A plant may wish to segregate to a
greater extent these wastes which it wishes to solidify.
This may involve some degree  of retrofiting.  Of those
wastes targeted for solidification, it is important  to
determine how the blending of the wastes will affect the
processes chosen for pretreatment and solidification. If
the waste is "hazardous" at the collection point and must
be stored for more than 90 days, you will require a permit
for this activity. A manifest will be required if the waste is
                                                   63

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 transported  off-site   for  solidification.  In-line
 solidification  would  be  required   to  avoid  these
 requirements.
   Waste Pretreatment.  Some wastes  can be solidified
 directly, while others may require pretreatment. Physical
 pretreatment  processes  required  by some  processes
 include  decanting,  centrifugation,  dewatering,
 evaporation, or calcination. To reduce leaching from the
 solidified  waste, cyanide destruction,  neutralization or
 chromium reduction may also be required prior to
 solidification. At  a regional treatment  facility these
 processes might be accomplished with another waste thus
 reducing the cost. The generator who  requires chemical
 treatment prior to  solidification  might  search  for a
 process which does not  have this requirement.  If the
 treatment alone detoxifies the waste, there may  be no
 need to solidify the waste except for handling.
   Solidification  Agent Addition. There  are five basic
 types of  solidification as it may be applied to  this
 industry. These types include the following:
    Cement-based
    Lime-based
    Thermoplastic-based
    Organic Polymers-based
    Encapsulation and Coatings
Each of the processes in these categories has its own
requirements for adding the agent.  The amount  of
additive will probably be dictated on the lower end by the
specifications required  to pass  the structural integrity
procedure.   Other  specifications  may  be  required
depending upon the end use of the material.
  Mixing/Packaging Systems.  Solidification is  often
conducted either in a container or by in-line mixing with
containerized  or uncontained discharge. In-container
mixing  of the waste and solidification  agent can  be
accomplished  with  roller mixers,  tumbler  mixers  or
paddlemixers. In-line mixing  is accomplished either by
dynamic or  batch mixing. If  containers are used, they
must still be inspected, monitored and labeled. Interim
storage and track leading facilities will also be required.
Uncontained release is directed to the  disposal facility.
  Disposal.  If the solidified waste has been tested and
deemed to be nonhazardous the disposal site must meet
RCRA Section 4004 requirements at a minimum. There
may be pressure brought to bear by the states to upgrade
these requirements. However, if all the solidified wastes
going into a  landfill are deemed nonhazardous,  the
landfill  need  not  be a  secure  chemical landfill  for
hazardous wastes. There are a number of productive uses
of solidified wastes which  may decrease the need for strict
disposal  and provide an incentive  to the  use   of
solidification.  Some  of these  demonstrated uses are as
follows: land reclamation, road bed aggregate, artificial
reefs,  parking lot pavement,  impermeable liners, and
landfill capping material.


CONCEPT  INSURANCE
  Questions are often asked as to whether the solidified
waste will hold up over  time. To insure  that this will
happen, physical, leach and accelerated environmental
testing may be required on representative samples using
established protocols. EPA has sponsored a number of
studies to look at some of  these questions. Unfortunately
most of the solidified wastes were not  designed to meet
the common point  of passing the structural integrity
procedure. Varying amounts of additives  were used by
the participating vendors making comparisons between
processes  for a particular waste  type  very difficult.
Furthermore, there is no great amount of concensus in
the testing area. However, ASTM has recently mounted a
special effort to solve this problem.
  Accelerated testing is  perhaps the most controversial
aspect of concept insurance.  Most  tests  which  are
designed  to  be  representative  of  environmental
conditions take too long to generate useful data. Just as
aerospace construction  and  electrical components are
tested for long-term viability with accelerated techniques,
a similar approach must be adapted to the wastes. The
selection of the proper test should be attempted only after
the use of disposal technique is specified.

ON-SITE vs OFF-SITE SOLIDIFICATION
  This is  a  real controversial choice confronting the
generator.  Off-site  regional  solidification  offers
economy of scale and potential to  use other wastes for
neutralization  and  other pretreatment. A  potential
problem is that the wastes will be mixed with other wastes
and there is a question of potential future joint liability.
The wastes must also be manifested with this option if
they are  hazardous.  On-site  solidification gives  the
generator more control over the processing and handling
of his own  wastes.  It may  also remove some of the
manifesting  requirements.   Some  solidification
technology vendors operate exclusively in one mode or
the other.  Other vendors operate in either mode to suit
the needs of a customer. Legal and economic factors must
be  carefully weighted by the  waste generator before
deciding which  route to  take.

CONCLUSIONS
  Solidification has   great  potential as an advanced
pollution  control  technology  for  the metal finishing
industry.  New EPA regulations  should   hasten  the
development  and  incorporation of  solidification
techniques into a much broader segment of the industry.
Solidification should be considered as an option in the
hazardous waste management planning that each facility
must go through in order to be brought into compliance
with the RCRA regulations.

REFERENCES
Pojasek,  R.  B.,  editor. Impact   of  Legislation  and
  Implementation  of Disposal Management Practices,
  Ann Arbor, Michigan: Ann Arbor Science Publishers,
  1980.
Pojasek,  R.  B., editor.  New and Promising Ultimate
  Disposal Options, Ann Arbor, Michigan:  Ann Arbor
  Science  Publishers, 1980.
Pojasek, R.  B.  "Solid-Waste Disposal: Solidification."
  Chemical Engineering, August 13 (1979):  87.
Pojasek, R.  B.  "Novel Approach to Hazardous Waste
  Disposal in New England." J. N. E.  Water Pollution
  Control Assoc.  13  (179): 36-46.
Pojasek,  R.  B. "Disposing of  Hazardous Chemical
  Wastes." Environ.  Sci. Technol.  13 (1979): 810-814.
Pojasek,   R.  B.,  editor. Stabilization/Solidification
  Processes for Hazardous Waste Disposal. Ann Arbor,
  Michigan: Ann Arbor Science Publishers,  1978.
Pojasek,   R.  B.,  editor. Stabilization I Solidification
  Options for Hazardous Waste Disposal. Ann  Arbor,
  Michigan: Ann Arbor Science Publishers,  1978.
Pojasek,  R.   B.  "Stabilization/Solidification  of
  Hazardous Wastes." Environ. Sci. Technol. 12(1978):
  382-386.
                                                    64

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         Radioohemioal  Studies of the Leaching
     Of  Metal  Ions from Sludge Bearing Concrete
                               John D. Mahoney and Elaine A. Dwyer*
                               Walter P. Saukin and Robert J. Spinna**
 INTRODUCTION
   The possibility of incorporating electroplating sludge
 into concrete as an alternative disposal procedure to the
 use of segregated landfills has been examined earlier in
 the report of work done under Research Project 49-Phase
 I of the American Electroplaters' Society.' The ultimate
 rationale for this exploratory study was the fact that the
 ready-mix  concrete  industry  in  the United States
 provides a potential daily capacity for disposing of more
 wastewater sludge than the entire electroplating industry
 generates on the same daily basis at a cost which could be
 significantly less than that of current disposal methods.
   While the  chemistry  of  concrete  is  not  fully
 understood, it is known that the hardening process is the
 result  of the  reaction of  calcium  silcates,  calcium
 aluminates, and tetracalcium alumino-ferrite with water
 to form hydrates that  resemble the natural  minerals
 tobermorite and  the hydrogarnets as well as other
 hydrates and calcium hydroxide. These reactions are
 summarized in Figure 1. The most important of these is
 tobermorite which, in concrete, is formed in an extremely
 finely divided manner with a coherent structure that is
 given the name gel. Thus the hardening of concrete can be
 seen  as the  process  of  making  artificial  minerals.
 Aluminum, iron, and some of the calcium in concrete are
 bound and rendered insoluble in the same manner as
 these metals  are  bound  in natural  rocks. It is  not
 unreasonable that other metal ions could be mineralized
 in this manner. In addition, the possibility exists that the
 metal ions  could be immobilized within the molecular
 sized gel pores that  are formed in concrete during the
 hardening process. The extent to which metal ions have
 been mineralized in  concrete, made with electroplating
 sludge as part of the mixing water, can be determined by
 analysis of the leach water. While other testing may be
 required to  establish the exact nature  of the metal
 binding, leaching studies will give  evidence  of  the
 feasibility  of  the  method  and  indirectly  of  its
 environmental acceptability.
  Radiochemical techniques for conducting these studies
 were employed because they provide a fast/accurate,  and
 extremely sensitive method of identifying the metal  and
 its concentration in the leach water.
  The  results  obtained in phase  I were sufficiently
 encouraging, in respect to both the quality of the concrete
 'John D. Mahoney and Elaine A. Dwyer
 Chemistry Department, Manhattan College
 Bronx, New York 10471
"Walter P. Saukin and Robert J. Spinna
 Civil Engineering Department, Manhattan College
 Bronx, New York 10471
and the binding of the metal compounds, that phase II
was undertaken. This  paper will consider the leaching
studies that were done in both phases of the work to
determine the extent to which metal ions leave sludge-
bearing concrete and enter ambient immersion water. In
some respects this can only be a progress report; the final
results will be  included in the report to be given at
SUR/FIN '80 in Milwaukee this June.

EXPERIMENTAL PROCEDURES
  In both phases of the work the composition of the
concrete mix was the same as that used in the physical
tests. It consisted of a water/cement ratio of 7.0 (gal/ft3)
and an aggregate/cement  ratio  of 5.5 (Ib/lb).  The
aggregate was  35% sand, 65% coarse aggregate.  This
corresponds to a conventional 1:2:4 mix. In phase I, only
Type I normal Portland cement produced by the Saylor
Portland Cement Company was used. In phase II, both
Type I (Saylor) and Type III High-Early-Strength (Atlas
Portland  Cement   Company)  were  used.  The
compositions of these  cements are shown in Table 1.
Type  III cement  has  a very  large tricalcium silicate
content because it is this substance that hardens rapidly
and is largely responsible for  the  initial set and early
strength of concrete. In phase I  the  coarse aggregate was
washed natural stone; in phase II, 3/8" crushed trap rock
was used.
  The water component was replaced by sludge that was
adjusted to a 1.5% solid component in phase I and a 2.0%
solid component in phase II. The  sludge was obtained
from the following sources:
New England Plating Co., Inc.
 Worcester, Massachusetts
WHYCO Chromium Co., Inc.
 Thomaston, Connecticut
Contract Plating Co.
 Stratford, Connecticut
                      NEP

                  WHYCO

                      CPC
    2(3CaO-SIOi) + 6H,O
  (Tricalcium Silicate)

    2(2CaO SIO,) + 4H,0
  (Dlacalcium Silicate)
3CaO 2SI02 3H20 + 3Ca(OH),
    (Tolbermorlte Gel)

3CaO 2810,3H2O + Ca(OH),
   {Tobermorite Gel)
    4CaO AljO, Fe:O, + 10H2O + 2Ca(OH),
  (Tetracalcium Alumlnoferrlte)

     3CaO AI;O, + 12H2O + Ca(OH): ^
  (Tricalcium Alumlnate)

    3CaO AI;O, + 10H;O + CaSO, 2H:O
  (Tricalcium Alumlnalei    jGypsum)
      ^  6CaO AI,Oj FejOj 12H:O
       (Calcium Alumlnolerrlte Hydrate)
           (Hydrogamet)

     _ 3CaO AI,O, Ca(OH); 12H2O
      (Tetracalcium Alumlnate Hydrate)

         3CaOAI,O,CaSO,12HjO
       (Calcium Monosulfoalumlnate)
                                                      Figure 1—Chemical Reactions in the Hardening of Concrete.
                                                  65

-------
The radioactive nuclides that were used were mixed with
the appropriate quantity of sludge  and allowed to
equilibrate. The cement and aggregates were dry mixed.
The liquid and solids were hand blended until a uniform
mix was obtained, which was then mechanically agitated
and placed in forms. Separate batches were prepared for
e>ch metal and cement variation. The batch  size was
sufficient to prepare three  2-inch by 4-inch cylinders,
except in the case of the  final experiment in which the
EPA Toxicant Extraction  Procedure2 was followed when
only a single cylinder was prepared.
  The radionuclides employed for the metals tested and
their  relevant  properties,  the  sludge  sources, the
concentration of the metals present in the sludge, and the
type of cement used are summarized in Table 2.
  All of the cylinders were cured under conditions of
100% humidity for 48-72 hours when Type I cement was
used, and for 72 hours to a  week when Type III cement
was  used. Following this, the concrete cylinders were
separately immersed in beakers containing 400 ml of
deionized water,  which  were  kept  tightly  covered.
Sampling of the leach water was done  periodically. For
the *5Ca, 63Ni,  26A1, and I15mCd systems, four-1.0 ml
aliquots were transferred  successively to planchets and
evaporated to dryness. The radioactivity of each planchet
was  measured in  a windowless gas-flow proportional
Table 1
Composition of Various Types

Tricalcium Silicate
Dicalcium Silicate
Tricalcium Aluminate
Tetracalcium Alumino-
ferrite
Total
I
53
24
8

8
93
II
47
32
3

12
94
of Cements
III
58
16
8

8
90
IV
26
54
2

12
94
V
40
40
4

9
93
counter. Background and  standard counts were taken
before and after each days counting.
  The leachates from the 65Co,  51Cr, 54Mn, and 65Zn
systems  were sampled by taking a single 4.0 ml aliquot
from each. The three 4.0 ml aliquots for each system were
combined in the same vial, except in the chromium-high
early  system,  where each leachate  was  measured
separately, because each cylinder was given a different
state of  integrity. A 400-channel analyzer with a 3" X 3"
Nal well counter and a 1024-channel analyzer with a
standard Nal well counter were used for the T-counting.
They  were calibrated periodically using l37Cs and 60Co
standards. Each sampling, which represented exactly 1%
of the leach water, was replaced with the same amount of
deionized  water thus maintaining a constant leachate
volume. It should be noted that  typical cylinder had a
mass of 440  g and a volume of 210 cm3. Thus fixing the
leachate volume at 400  ml made a very confined and
virtually stagnant system. It was judged that this would
resemble most  severe natural  conditions.  In  the final
experiment,  however, the  EPA procedure, requiring a
water mass of 16 times the mass of the solid material, was
followed.
  In addition the pH of the leach water in the control
samples was measured each day. In the final experiment,
again following EPA procedure, the pH of the leach
water was  maintained at 5.0 for 6 days by the addition of
0.5 M acetic acid.
  Measured counting rates were  converted to absolute
disintegration rates by computational methods outlined
in Chandra3  and Snell4, and by  the use of reference
sources. Decay  scheme  corrections were  used where
appropriate. When nuclides of short half-life were used,
all disintegration rates were normalized to the day on
which the  samples were prepared.

RESULTS AND DISCUSSION
  This section will be divided into subsections, each of
which  will   consider   one  of   the   metals  tested.
  The chemical form of the metal  is not determined. It is
assumed that the radioactive isotope equilibrates with the
Table 2
Cement type
Radionuciides and relevant properties

26AI
45Ca
"5mCd
60Co

5,Cr

54Mn
"Nl

"Zn

Half life
7.2X105 yr
165d
44.6d
5.27 yr

27.7d

312.5d
120 yr

244d

Energy (MeV)
1.16™
0.253™
1.62™
1.173
1.332
0.320
(from
0.835
0.066™

1.116
(from
Particle
j3*(82.1%)
tf*" / 1 n no/ \
13 I 1 UU /O J
/T(100°/o)
T
T (99 + %)
T(10%)
51 v)
T(100%)
0~(100%)

T(50.7%)
65cu)
Activity
Incorporated
(MCI)V
cylinder

0.0015
3.3
13.3
1.7

167

1.7
33 phase I
13.3 phase II
3.3 phase I
1.7 phase II
Sludge
source

CPC
—
NEP
WHYCO

NEP

WHYCO
NEP

NEP

Metal
concentration Cement type
in sludge used

to be determined
~45% of cement
600 ppm added
500 ppm added

600 ppm added

300 ppm added
270 ppm phase I
510 ppm phase II
300 ppm phase I
570 ppm phase II

I
I
I &III
I

I &III

I
I
I &III
I
I &III
* VCi = 2.22 x 106 disintegrations/min
                                                    66

-------
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5 0.16
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5
S
0.04

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I I
I T I
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T '
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         3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60

                        DAYS LEACHING
Figure 2—Concentration of Cd In leach water as a function of Immersion
time of sludge bearing concrete by beta counting.
naturally occurring isotopes in the sludge and adopts the
same chemical states as the latter  in all parts of the
system.
1. Aluminum
   The results with respect to the rate at which this metal
is leaching from the concrete are inconclusive. The lower
limit of detection is about  1 ppm because of the small
amount of radio-activity that was incorporated. Because
it is cyclotron produced, 26A1 is very expensive - about
$500/0.01 /uCi. To obtain an increase in sensitivity of 10,
about  0.05 pCi would have to be used. Hence, other
methods  of  rapid and  sensitive analysis  are  being
investigated.  Nevertheless,  the  measured  activity of
samples taken over a period of 118 days of leaching was
never consistently above background. This leads us to
conclude  that the aluminum from  aluminum bearing
sludge does not leach to an extent greater than 1 ppm in
this system.
2. Cadmium
   Because none of the sludges  used were  known to
contain cadmium, it was added  to  the NEP sludge as
Cd(NO3)2-4H2O  at  a  concentration  of  600  ppm.
Cylinders were made using  both  Type I and Type III
cement. The results obtained for this metal are shown in
Figure 2.  They appear to be higher than for  any of the
other metals, especially in the case of the Type I cement.
For cylinders made with Type HI cement, the leaching is
generally lower.

3. Chromium
  There were four different chromium systems studied.
The first  consisted  of  a   chromium-bearing sludge
incorporated into concrete made using Type I cement.
The other three used the same chromium-bearing sludge,
but the concrete was made using Type III cement. Of the
three cylinders prepared in this way, one was allowed to
remain integral, another was broken into larger pieces
(about 1 1/2" in diameter), and the third was broken into
pieces about 1/2" in diameter just prior to immersion in
the leach water.  As  the data  presented in Figure  3
indicate,  there is  very   little  difference  among the
samples. Apparently, the increase in surface area among
the three Type III  cylinders is not noticeably affecting the
leaching of chromium. This suggests that the binding is
not merely interstitial entrapment. The general lowering
of the  metal concentration with time is not peculiar to
these   systems  as  will  be   seen   subsequently.  The
implications will be discussed later.

4.  Cobalt
  Only Type I cement has been used to date in the study
of cobalt leaching. The concentration of soluble cobalt
entering the leach water as a function of time has  been
reported earlier.5  After about 30 days the level reached
about 0.004 ppm where it remained for the next 30 days
and then began to diminish. The total cobalt that entered
the leach water (soluble plus insoluble) was found to be
about five times that of the soluble alone, or about 0.020
ppm at 60 days and 0.010 ppm at 90 days. After 100 days
the entire leach water was removed  from all the cobalt
samples and replaced  by an equal volume of deionized
water.  The cobalt  radioactivity as a function of time for
these systems was measured. The results are shown in
Table  3.  Both  soluble   and  insoluble  cobalt  were
measured.  The   generally lower  results  should be
attributed to the concrete being cured for over 100 days
before  this  new exposure. Again the tailing off of the
metal concentration with time is  to be noted.

5.  Manganese
  Only Type I cement has been used to  test the leaching
characteristics  of manganese.   There  is  no soluble
manganese in the  leach water during the first 60 days of
leaching as reported earlier.6 The insoluble manganese
has been found to have a maximum value of about 0.04
ppm after 90 days of leaching. When  the leach water was
replaced after 100 days, the  manganese concentrations
reached about  0.037  ppm after 21 days  and began
diminishing to 0.024 ppm at 48  days and  0 by 116 days
where they remained through 176 days. Our lower  limit
of detection is 0.00004 ppm in this system.

6.  Nickel
  The soluble nickel concentrations in the leach water for
the first 60 days  of leaching from concrete made  with
Type I cement were  reported earlier.7 They ranged from
about 0.0015 ppm during the first 20 days to 0.005 by the
fortieth day, and  0.003 at the end of 60 days. We  have
subsequently measured the total nickel entering the leach
                                                  Table 3


    Days leaching              7        21        48       116      143
    Cone, of cobalt
     in the leach water (ppm)   0.0010    0.0022    0.0066    0.0005      0
                155      162      172      176

               0.0003    trace    0.00005      0
    Note: the lower limit of detection is 0.00004 ppm
                                                    67

-------

ffi 0.10.
X
0 _ 0.08
< z
,5S 006
»E
CONCENTRATIO
(PART
0 e
g S
O Typel
A Type III (large piece.)
D Type III (Integral)
1 O Type III (.mall piece.)
|
1
. i T A * A i,
36912 15 18 21 24 27 30 33 36 3» 42 45 48 51 54 57
                          DAYS LEACHING
I «
g _ 0.04 •
|g 003
ENTRATION O
(PARTS Pi
o
8
g 001
8




|f
I


1 0 Typel
1 A Type III


t ,
. A
i 1 T I
i iAi 1^1 i i T 	 1. , ,
Figure 3—Concentration of Cr In leach water as a function of Immersion
time of sludge bearing concrete by Gamma counting.
           3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 M 57 60
                          DAYS LEACHING

Figure 4—Concentration of Nl in leach water as a function of immersion
time of sludge bearing concrete by Beta counting.
 water as a function of time for both Type I and Type III
 cement formulations. The results are shown in Figure 4.
 For concrete made from Type I cement, the total nickel is
 about five times the soluble nickel with a maximum value
 of  0.035  ppm.  For Type  III cylinders  the  results are
 dramatically  lower,  in   which,  the  total   nickel
 concentration in the leach water never reaches 0.01 ppm.
  Cylinder systems, in which, the leach  water was
 replaced after 100 days show an initial release of nickel
 into the fresh leach water at a level of about 0.02 ppm
 after seven days. The concentration drops to 0.01 ppm in
 21  days, and to about 0.005 ppm by the  165 day.
  Because the 63Ni emission is a  very  low  energy 13'
 particle, the  efficiency measurement is subject to some
 uncertainty. It is possible that when a refinement of this
 measurement is made, the results reported might have to
 be  raised by a factor of two at the most. This would have
 the effect of making the highest nickel concentration 0.07
 ppm.

 7.  Zinc
  Previous measurements of soluble zinc entering the
 leach water,  when type I cement was used, showed no
 detectable metal during the first 60 days.8  The lower
 detection limit  is  about 0.0001 ppm. The total  zinc
 entering the  leach water as a function of time for both
 Type I and Type III formulations is shown in Figure 5.
 The Type III,  high early strength  cement, produces a
concrete,  which for zinc, allows  release at the  barely
detectable level of slightly greater than 0.0001 ppm. Even
Type I cylinders release the zinc at an extremely low level.
The zinc cylinders that were reimmersed after 100 days
showed an initial release of about 0.020 ppm with the
concentration diminishing to 0 by the  116 day.

8. Measurements Based on  EPA Protocol for Toxicant
   Extraction
  One cylinder was prepared with NEP sludge to which
650 ppm manganese from MnCl2-4H2O was added with
1.0 juCi 54Mn. After curing, the cylinder was  immersed in
16  times its  mass of deionized water and  the pH was
adjusted to and maintained at 5.0 using 0.5 M acetic acid
for 6 days with constant agitation. At the end of 24 hours,
there was no 54Mn activity in  the ambient water. At the
end of 6 days, the water showed  a 54Mn activity of 40
counts/hr., which is equivalent to 0.008 ppm.

9. Calcium and the Nature  of Metal Binding
  The last metal  to  be considered with respect  to its
leaching from concrete is calcium. While it is generally
not a constituent of electroplating sludge, it does make up
about 45% of Portland cements. In hardened concrete,
calcium  is present in mineralized form (tobermorite,
hydrogarnet, and aluminates), and as Ca(OH)2.
  As was reported earlier,"*  (Figure  6), a significant
                      O  Typel
                      A  Type III
          3  6  9  12 15 18 21 24 27 30 33 38 39 42 45 48 51 54 57 60

                         DAYS LEACHING
|
1
So
H
O '
SS
IL. 
-------
Table 4
Drinking Water Standards and Typical
50-day Leachate Metal Concentrations
Drinking Without
water (ppm) Leachate confinement
(ppm) (ppm) (ppm)
Cadmium
Chromium
Cobalt
Manganese
Nickel
Zinc
0.010 0.1
0.050 0.03
0.0095* 0.02
0.050 0.04
0.034* 0.01
5 0.001
'Maximum concentration
cities in 1962.
65
65
58
33
30
61
in finished water of 100 largest U.S.
amount of calcium enters the leach water, about 1% of
the total calcium content of cement. The pH of the leach
water reaches 12.5 by the 25th day of immersion in the
systems used in this work. Thus, if it is assumed that the
entire hydroxide ion concentration is due to Ca(OH)2, a
calcium concentration of 630 ppm is obtained, which is
very close to our radiochemically determined value of 614
ppm.  Nearly 1% of all the calcium in the cement paste
leached out in about 30 days. During the same period of
time, less than 0.02% of the metals in the sludge leached
out. The metals in the sludges used are present primarily
as hydroxides. (The pH of these sludges is 8-8.5.) Even if
this were not true the large excess of hydroxide ions in
fresh concrete would tend to convert them to this form.
Thus it seems to follow that, whereas calcium in the form
of Ca(OH)2 is  not  effectively immobilized,  the other
metals are. If these metals remained in the hydroxide or
other nonmineralized chemical forms, they should show
about the same leaching properties as calcium. The fact
that they  do not suggests they  are at least partially
mineralized. Additional  evidence supporting  the
conclusion that compounds are chemically immobilized
in concrete is to be found in the literature search of our
report on  phase I of the project.10
  A puzzling aspect of the sludge-metal leaching  systems
is  the  apparent reabsorption of certain metals with
extended exposure of the  concrete  to the same leach
water. This is observed in the majority of cases. It is as
difficult to dismiss it as it is to explain it. It is not due to
the  lessening  of  radioactivity  with  age  because  a
correction based on half-life was made for the counting
rates of all  short-timed nuclides. This  phenomenon is
fortuitous for the purposes of this work, and it is hoped
that future studies will elucidate  its causes.
  In conclusion it should be pointed out that the extent
to which  the metals studied leach  into the ambient
immersion water is generally of a very low level. For
purposes  of comparison, the maximum contaminant
levels in drinking water (1974 Safe Drinking Water Act
and  1962  U. S. Public Health  Standards) are shown
in Table 4 together with the 50-day metal concentrations
determined  in this study. It should be noted that the
Resource  Conservation and Recovery Act sets control
values at 10 times these levels. A third column is included,
which shows metal ion concentrations  in  the same
volume of  water  if the metals  were  added  without
confinement.

FOOTNOTES
  1.  The Effect  of Electroplating Wastewater Sludge as
   an Admixture on the Physical Properties of Concrete
   -   Phase   I,   Report  to  American  Electroplaters'
   Society, on Project No. 49, October  20, 1979.
  2.  Resource Conservation and Recovery Act proposed
   test method.
  3.  Chandra, R.,  Introductory  Physics  of Nuclear
   Medicine,  Chapter 9,  Lea   and  Febigger,
   Philadelphia, 1976.
  4.  Snell,  A. H., ed.,  Nuclear Instruments and Their
   Uses, Vol. 1, Chapter 5, John Wiley  and Sons, New
   York, 1962.
  5-10. The Effect of Electroplating Wastewater . . .

ACKNOWLEDGMENTS
  The authors gratefully acknowledge the support of this
research by the American Electroplaters' Society as part
of Project No. 49.
  The authors are very appreciative of the assistance of
Louis  Pasquale, who  performed the  pH  controlled
experiment and helped with the calculations. In addition
they wish to thank  Herbert K. Miller,  Br. Austin
Bernabei,  Lawrence J. Durney,  Cort G.  Platt, Frank
Principe, Vincent Ranelli,  and  Bruce  E. Warner for
cooperation, support, and helpful advice during various
stages of the work. Finally, a special note of thanks to
Geraldine  Rooney  for  her  expert  manuscript
preparation.
                                                    69

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             Stabilization of  Heavy Metal Wastes
                           By the Soliroc  Process
                                 J. M. Rousseaux and A. B. Craig, Jr.*
 INTRODUCTION
 1.1 PROJECT OBJECTIVES
   The primary objective of this study was to conduct a
 preliminary engineering evaluation of the Soliroc metal
 fixation process in immobilizing potentially hazardous
 pollutants contained in industrial wastes. The evaluation
 was designed to provide experimental data on the Soliroc
 process and to establish a data base for future pilot scale
 work. Additional project objectives include:
   •  Expedition  of preliminary  bench  scale
    experimentation of a fixation process currently used
    commercially in Europe.
   • Provision of  sufficient data that a  domestic co-
    sponsor  for  further  demonstration  could  be
    attracted.
   • Promotion  of the transfer  of  foreign fixation
    technology  which appears capable of storage or
    disposal of industrial wastes (especially metals) for
    future recovery.
   • Development of in-house expertise for treatment of
    wastes from the EPA Testing and Evaluation (T&E)
    facility.
   • Organization  and completion of the project in a
    minimum time period and at minimum cost.
   The project was implemented by personnel from the
 U.S.  Environmental  Protection Agency (EPA), with
 technical consultation by  Mr. Jean Rousseaux  of the
 Cemstobel  Company in Brussels,  Belgium. The
 contributions  of  Mr. Rousseaux  were  necessary in
 several phases of the experimental program,  especially
 those dealing with proprietary aspects of the  Soliroc
 process.
 1.2 SCOPE
   In  order  to meet  the  objective of the  study, the
 following tasks were performed:
  • Seven samples, representative of wastes from the
    electroplating  industry   were  obtained  locally
    (Cincinnati, Ohio).
  • Raw wastes were analyzed for metals, cyanide (CN),
    and hexavalent chromium (Cr+6).
*J. M. Rousseaux
 Cemstobel
 Brussels, Belgium
 A. B. Craig, Jr.
 Industrial  Environmental Research Lab.
 U.S. EPA, Cincinnati, Ohio
  • The   Soliroc  process  used  was  designed  to
    accommodate the study wastes and the bench-scale
    experimental protocol.
  • Waste samples were treated with the Soliroc process.
  • The  EPA  extraction  procedure  (EP) test  was
    performed on the treated wastes.
  • Compression tests were performed on treated wastes
    (test cylinders).
  • Analytical results of stablized waste samples were
    compared to RCRA's EP toxicity limitations, the
    National Secondary Drinking Water Standards and
    to the raw waste analyses.

SECTION 2
BACKGROUND
  The  metal finishing  industry  generates a variety of
waste  materials  that  are  potentially  hazardous.
Electroplating  process residues, pickling acids,  and
wastewater treatment  sludges contain cyanides  and
heavy metals. Two methods commonly used for disposal
of the materials are landfilling and ponding; both have
been practiced without any particular precautions being
taken to prevent them from contaminating ground water
supplies. Inorganic residues and sludges from the metal
finishing industry can be chemically bound to minimize
the potential for groundwater contamination by effecting
a change in the chemical and physical properties of the
wastes. A number of  fixation  techniques  have  been
studied,  including precipitation,  encapsulation,
asphalting, cementation, and other similar stabilization
processes.  A list of pertinent references is shown in
Appendix A. This report discusses an evaluation of one
fixation process, called the Soliroc process which was
developed by Cemstobel, located in Brussels, Belgium.

2.1 REGULATORY ASPECTS
  Through a number of specific provisions, the Resource
Conservation and Recovery Act of 1976 (RCRA) aims to
promote the protection of health and the environment
and to conserve valuable materials and energy resources.
Subtitle C of RCRA directs the U.S. EPA to promulgate
regulations to protect human health and the environment
from the improper management of hazardous waste. In
accordance with that direction, EPA has promulgated
the Hazardous  Waste  and  Consolidated  Permit
Regulations (Federal Register, May 19, 1980).
  More specifically, Section 267.24 of the  May  19
regulation indicates that one of the  most  prevalent
pathways by which hazardous wastes  migrate to the
environment and contaminate groundwater is through
                                                 70

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the leaching of waste contaminants from land disposed
wastes. It is obvious from the history of RCRA that this
type of ground water contamination was one of Congress'
primary areas  of concern.  EPA  has addressed the
problem of identifying potentially leachable  wastes by
developing an  analytical test  procedure called the
Extraction Procedure (EP).  The  EP test is  discussed
more fully in Section 4.1. This test method was designed
to simulate the  leaching action that occurs in landfills.
The simulated leachate, or extract, from the  EP test is
analyzed  and compared with  the National  Interim
Primary Drinking Water Standards (NIPDWS). If the
extract is found to contain contaminants in excess of 100
times the maximum allowable limit set by the NIPDWS,
the waste is considered hazardous.

2.2 SOLIROC PROCESS DESCRIPTION
  Existing waste treatment processes precipitate metal
cations as hydroxides by adding a base, usually caustic or
lime,  which  produces an insoluble solid or  sludge.
However,  these metallic hydroxide  sludges  can  be
resolubilized in lower pH environments, as their stability
is pH dependent.
  In the Soliroc process, a chemical reaction takes place
between metals present in an acid solution and  a siliceous
reagent. During the chemical reaction, a monomer is
synthesized, which then polymerizes to form an insoluble
bulk mass that is believed to be suitable for landfilling.
  A process flow diagram of the Soliroc process in shown
in Figure 2-1. Initially, hexavalent chromium is reduced
to the trivalent state to allow for further reaction in the
process. During the reduction of chromium, the addition
of acid is necessary to maintain the pH  of  the waste
solution at about 1.5. For production of the monomer, a
siliceous reagent is slowly blended into solution, again at
a consistently low pH. The addition of waste or fresh acid
is necessary to maintain the low pH.
  The  pH is then raised by  the addition of  caustic to
about pH  11 to initiate polymerization. The rapid rise in
pH causes a thickening of the material, and subsequent
development  of  sludge  or  paste.  Following  the
polymerization  step, lime and a setting agent  such as
Portland cement can be added to effect coagulation and
hardening before the product is placed in  a landfill.

2.3 SUITABLE WASTES FOR TREATMENT BY THE
SOLIROC PROCESS
   Inorganic wastes,  as well as polar organic  wastes,
regardless of their degree of  consistency are reportedly
treatable by the Soliroc process. Some of these types of
wastes are listed below:
    Inorganic compounds
    Acids— hydrobromic acid (HBr), hydrochloric acid
    (HC1),  nitrous acid (HNO2),  nitric acid (HNO3),
    sulfuric acid (H2SO4), and also other less common
    acids; an exception to treatment potential in this
    waste category is hydrocyanic  acid (HCN).
    Bases—potassium  hydroxide  (KOH),  sodium
    hydroxide (NaOH), hydrated lime [Ca(OH)2], and
    calcium carbonate (CaCOs).
    Heavy  metal—solid or liquid wastes containing
    heavy metals such as aluminum, antimony, silver,
    arsenic,  barium,  beryllium,  cadmium,  calcium,
    cerium, chromium (+3 or +6), cobalt, copper, tin,
    iron (+2 or +3), magnesium, mercury, nickel, lead,
    and zinc.
    Oxidizing agents—chromate,  chlorate,
    hypochlorite, and perchlorate  wastes.
    Polar organic compounds
    Wastes containing these compounds include paint
    sludge, phenol, fatty acid, fatty amines, alcohols,
    ketones, and residues from latex processing.
                     Table 3-1
             Waste Sample Identification

  Sample Waste
      No.                    Waste
        1      Bright dip chromate for cadmium.
        2      Accumulated cyanide solution and sludge from
               holding tank (large automatic electroplating
               rack).
        3      Sludge from bottom of cyanide zinc plating tank.
        4      Sludge from phosphate tank and carbon from
               nickel filters.
        5      Sludge from plant sump cleanout.
        6      Alkaline cleaner sludge.
        7      Waste sulfuric acid pickle liquor.
SECTION 3-EXPERIMENTAL PROCEDURES
  Waste  samples  obtained  from  the  electroplating
industry are  listed in Table  3-1. These samples were
selected randomly and may not accurately represent all
wastes  characteristic  of  this  industry.  They  are
considered typical,  and this  small  sampling  group is
believed to be adequate for this preliminary study.

3.1 ANALYSIS OF RAW WASTE  SAMPLES
  The  raw   waste  samples  were  analyzed  for
concentrations of metals, cyanide (CN), and hexavalent
chromium  (Cr+6).  CENTEC  Analytical  Services
performed the analyses of the raw waste samples. Results
are reported in Table 3-2.
Table 3-2
Analyses Results of Raw Waste Samples
(mg/l except as noted)
Sample
No.
1
2
5
6"
7
"pH units.

pff
1.05
13.00
10.06
13.19
<1.0

bMetal concentrations are given in
'Analysis not
performed.

CN
1.27
2,430
968
33.7
c

units of /ig/g


Cd
15,400
910
782
35.2
53.0

(wet weight


Cr
57,000
535
3,890
440
470

of sludge), as


Cu
450
1,850
25,500
13,800
39.0

received.


Ni
305
5,800
1,330
5,660
46.0




Pb
4.00
0.74
2,000
6,580
c




Zn
180
5,400
28,700
5,030
5,000



                                                     71

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                                                  Table 3-3.
                      Calculated Chemical Concentration of Raw Wastes After Pretreatment3

                                                               (mg/l)
         Sample Waste
             No.

              1
              2
              5
              6
  Cd

15,400
  600
  670
   37
   Cr

57.000
  510
 3,400
  450
  Cu

  450
 1,160
21,800
  903
  Ni

 305
3,500
1,140
3,700
  Pb

  4.0
  0.4
1,700
4,300
   Zn

   180
 5,250
25,200
 5,010
        'Pretreatment consisted of the addition of Sample 7, sulfuric acid pickle liquor (see Table 3-1).
3.2 WASTE ACCEPTABILITY AND PREPARATION
  Some wastes were pretreated for Soliroc processing.
Wastes containing cyanide (Samples 2, 3, 5, and 6) were
chlorinated  to  destroy  the  cyanide  complexes  in the
wastes.  Following   chlorination,  the   solution  was
acidified to pH 2 by adding pickle liquor (Sample 7). The
chemical concentrations of pretreated Samples 1 through
6 were calculated, and results are given in Table  3-3.
  After raw waste  characterization and  preliminary
screening of the wastes by data review, Samples 3 and 4
were  eliminated  from  further  evaluation.  Waste  3
contained  elemental zinc  in amounts  that  prohibited
obtaining  a  low steady  pH without  production of
hydrogen  gas  (H2)  at potentially  hazardous  levels.
Consequently, Sample 3 was discarded. Waste Sample 4
was discarded  because  high carbon  content interfered
with the measurement of pH.
  Elimination of these  samples in this  study does not
necessarily  imply that  these two  waste  types  are
unacceptable for treatment by the Soliroc process. They
were eliminated because of limitations in the scope of this
preliminary study.  The purpose  was  not  to  prove
universal application of this process, but to develop data
as a foundation for further investigations. On this basis,
wastes that were not readily compatible with this process
were not tested.
  The four remaining  samples (1,  2, 5, and 6) were
blended in a ratio that  is critical to  the success of this
process. The  basis  for determining  this  ratio  was
developed by Cemstobel and is proprietary information.
The wastes were  blended in the proportions shown in
Table 3-4.
  The resultant metal concentrations  were calculated for
the blended waste, with results as shown in Table 3-5. As
a quality assurance check, a sample of the blended waste
was titrated with caustic (NaOH) to confirm or invalidate
the  calculated  total  metal  concentration.   (The
assumption  here is  that  at  pH  10.5  all metals are
hydroxylated and the measured equivalents of NaOH
will indicate total equivalents of cation metals in solution
prior to titration and precipitation with caustic). This is a
relatively inaccurate  measurement, yielding values  that
can vary with the selected end point and with sample
characteristics.  This  analytical check resulted  in  1.44
cation equivalents per liter; the calculated metal content
was 1.25 cation equivalents per liter. These values are
considered reasonably  comparable,  and  are included
here as a means of verifying the calcuated concentration
values.
                             Sample
                              No.

                                1
                                2

                                5
                                6
                                  Table 3-4
                         Blended Waste Composition


                        Proportion  Waste identification

                            0.5     Bright dip chromate for cadmium
                            1.0     CN solution and sludge from holding
                                   tank on automatic rack
                            0.5     Plant sump cleanout
                            1.0     Alkaline cleaner sludge
                                                Table 3-5
                             Calculated Concentrations (mg/l) of Metals in the
                                             Blended Waste
                                  Cd
                                  Cr
                                  Cu
                                  Ni
                                  Pb
                                  Zn
                                                    2,890
                                                    10,390
                                                    7,100
                                                    2,640
                                                    1,710
                                                    7,650
                          3.3 FIXATION OF BLENDED WASTE
                            After blending of the wastes, the sodification treatment
                          procedure  was  followed  according  to  the  process
                          description given in Section,2.2. The figure shown in that
                          discussion  (Figure  2-1)  illustrates the  experimental
                          procedure. However, minor modifications were made to
                          the process and are discussed below.
                            In  the chromium reduction  step, sodium  sulfite,
                          Na2SO3 was continuously added to the blended waste to
                          act as the reducing agent. An acid pickle liquor (Sample
                          7),  supplemented by white sulfuric acid, was added to
                          maintain the pH at 1.5. Addition of the siliceous reagent,
                          and formation of the silicic acid solution were performed
                          in a reaction mixer.  Polymer initiation, by addition of
                          caustic, was also performed in the mixer. Addition of
                          lime and/or cement followed, and the mixer was emptied
                          into a suitable container for further testing.

                          3.4 EVALUATION OF THE SOLIROC PROCESS
                            Six  experimental  runs were performed, some with
                          variations of the standard process. Five experimental
                          runs used the blended waste sample, and one (Run 6) was
                          performed on raw pickle liquor. Table 3-6 outlines the
                          variations  applied  to all  runs. Runs 1  and 5 were
                          duplicates,  in  which  the  process  was  performed  as
                          described earlier. In  Run 2 addition of the pickle liquor
                                                      72

-------

RAW
1 HASTE
1
1 ELIMINATE
CN BY
CHLORINATION,,
REDUCTION
OF Cr*6
1
_. BLENDED
1 WASTE
PRELIMINARY
SCREENING
ADDITION OF
SILICEOUS
REAGENT
AND ACID


MONOMER

ADD IT
CAU
i
ON OF
>TIC


POLYMER

At
SE1

JDITION OF
TING AGENT
ADDITION OF LIME
1
^ CCMCN


FINAL
FATION 	 »•
DISPOSAL

              ANALYSIS
Fig. 2-1 —Flow diagram of the Sollroc process.

was omitted. In Run 3, the proprietary siliceous reagent
was omitted. Run 4 was similar to Run 2 except for the
cementation  step; Portland  cement was added in the
cementation  phase of Run 4, whereas no cement was
added during Run 2.

3.5 THE EPA EXTRACTION PROCEDURE
   Following is a  brief description of the EP test used as
the analytical basis for this study.
   A  100-gram sample  (approx.)  was  prepared for
extraction  by  reducing the particle size (by  crushing,
cutting or grinding) so that the sample material would
pass through a standard 9.5 mm  (3/8-in.)  sieve.  After
being weighed, the solids were placed in an extraction
container, to  which  16 grams of water were added for
every gram of solids. This mixture was stirred sufficiently
to assure that all sample surfaces  were continuously
brought into contact with the well-mixed extraction fluid
                      Table 3-6
                 Experimental Runs

  Experiment              Acid added   Cementation
   run No.  Waste blend   (Step 2f      (Step 4f

      1      1,2,5,6        Pickle liquor and Lime and setting
                          H2SO4         agent
      2     1,2,5,6        H2SO4         Lime and setting
                                       agent
      3     1,2,5,6        Pickle liquor   Lime
      4     1,2,5,6        H2SO4         Portland," lime,
                                       and setting agent
      5     1,2,5,6        Pickle liquor and Lime and setting
                          H2SO4         agent
      6     Pickle liquor    Not applicable  Portland,1" lime,
                                       and setting agent
 "Step numbers refer to the process description in Section 3.3.
 "Portland cement.
                                   and to prevent any stratification. The pH was adjusted to
                                   5.0 ±0.2, by use of 0.5 N acetic acid. The total addition of
                                   acetic acid was limited to 4 ml per gram of solid, beyond
                                   which  no   more was  added.  The  extraction  was
                                   maintained between 20° to 40°  C (68°  to 104° F) for 24
                                   hours. The mixture was separated as before into solid and
                                   liquid components. The liquid was diluted with distilled
                                   water to a total volume equal to 20 times the weight of the
                                   initial solid materials.  This liquid was the "extraction
                                   procedure elutriate," which was analyzed for metal ions.

                                   SECTION 4
                                   TEST RESULTS
                                     In addition to the planned EP test for evaluation of the
                                   stabilized   wastes,  two   additional  test  series  were
                                   conducted,  the results of which are also presented here.
                                   The Cemstobel Laboratory in Belgium performed metals
                                   analysis on samples referred to as core dips. A core dip is
                                   distilled water in which the stabilized wastes (Runs 1,2,4,
                                   and 5), in the form of solidified cores, were allowed to
                                   soak for about 30 days. This test was performed to allow
                                   comparision with the EP test results.
                                     The  second  additional  test  series  involved
                                   determination of the unconfined  structural stability of
                                   the cemented wastes. Three cores (6 in. diameter and 12
                                   in. long) from each experimental run were aged from 61
                                   to 66 days  and  submitted to  an independent testing
                                   laboratory.  Each core was compressed to the failing
                                   point,  and  the  total   load  recorded.  The   total
                                   compressional load required to cause failure, relative to
                                   the cross sectional area of the core, yields a value for
                                   compressive strength in units of pressure (psi).

                                   4.1 EP  RESULTS
                                     Data obtained  in the EP test are shown in Table 4-1.
                                   The maximum allowable acetic  acid column is shown, in
                                   accordance with the limitation of 4 ml 0.5 N acetic acid
                                   per gram of solid sample. It  is noteworthy that the
                                   maximum allowable  volume of acetic acid was required
                                                   Table 4-1
                                         EPA Extraction Procedure Data
       Run No.

           \
           2
           4
           5
           6
Stabilized waste
sample size, g

 99.5
 99.4
105.0
100.6
102.5
Initial
pHofEP
extract

lO.l
10.7
11.4
10.4
ll.O
Final
pH of EP
extract

7.2
6.6
9.1
7.3
9.5
0.5N HAc"
added, ml

  398.0
  397.6
  420.0
  402.4
  410.0
 Max. HAc*
allowable, ml

    398.0
    397.6
    420.0
    402.4
    410.0
     "HAc = acetic acid.
                                                      73

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Table 4.2
Analyses of EP Extracts
mg/l
i\un - — • 	 — 	
No. Cd Cr Cu Ni Pb
1 5.60 0.10 0.28 1.30 0.013
2 2.30 0.27 0.64 0.95 0.016
4 0.10 0.13 0.06 0.15 0.006
5 2.70 0.18 0.36 1.15 0.017
6 <0.01 0.50 0.05 <0.10 0.008
Maximum allow-
able concen-
tration 1.0s 5.0" 100.b c 5.0a
"Characteristic of EP toxicity from RCRA (100 times NIPDWS).
b!00 times the secondary maximum contaminant level.
'Nickel is not regulated by the primary or secondary drinking water standards.
in every case, an indication of the strong alkalinity of the
setting agent and Portland cement added during the
stabilization of waste samples.
The results of analyses of the EP extracts are shown in
Table 4-2. The maximum allowable concentrations for
each metal were determined from the promulgated
RCRA regulations for cadmium, chromium, and lead
and from the secondary drinking water standards for
copper and zinc. The principle of an attenuation factor of
100 that is the basis for the RCRA maximum
contaminant levels was applied to the secondary drinking
water standards.
4.2 RESULTS OF ADDITIONAL TEST RESULTS

Results reported by Cemstobel for analysis of metal
concentrations in the core dip samples are shown in Table
4-3. Lead concentration was not determined on these
samples. Results of the compressive strength tests are
shown in Table 4-4.
SECTION 5
DISCUSSION OF RESULTS
A rnmnarative nresfintatinn of the analytical results
Table 4-4
Results of Compressive

















Strength

Total load,
Run No. Age days
\ t\f\
I OO
1 66
66
2 66
66
66
4 64
64
64
5 63
63
63
6 61
61
61

pounds
i ^n
1 JU
250
250
2,000
1,900
1,800
4,250
4 500
4'SOO
500
500
650
1,500
1,550
1,500




Zrt
34.8
5.00
0.41
25.0
0.50


500."




Test

Unit load,
psi
C
J
9
9
71
67
64
150
159
159
18
18
23
53
55
53

from the EP tests is shown in Figure  5-1. Except for
cadmium, the EP extracts gave concentrations of the
metals  below  the  maximum allowable concentration.
Only   one  experimental  run  stabilized  cadmium
satisfactorily. This observation leads to the preliminary
conclusion that the Soliroc process, as it was modified for
this study, may not be  capable of  stabilizing wastes
containing cadmium in the range of 2000 to 3000 mg/1.
The contaminant that appears most easily stabilized is
lead, which however, was present in the blended waste at
the lowest concentration of all the metals. Results of the
EP extract analysis for lead average 0.013 mg/l, well
below the maximum allowable concentration.
Table 4-3
Analyses of Core Dip Samples
(mg/l)
Run No.
1
2
4
5
Cd
0.004
'0.01
0.3
0.005
Cr
0.04
0.04
0.04
0.02
Cu
0.5
0.3
0.14
0.12
Ni
0.31
0.46
0.21
0.28
0\23
0.23
0.007
0.03
0.02
  The results of Run 6, in which pickle liquor (without
additional waste) was used as the starting material for the
process,,are not shown on Figure 5-1 for two reasons.
First, the metal concentrations in the starting materials
are not comparable, and second, the EP extract analyses
for Run 6 yielded relatively low metal concentrations (see
Table 4-2). The data indicate that the Soliroc process is
adequate   in  immobilizing  potentially  hazardous
constituents of sulfuric acid pickle liquor. The cadmium
concentration in the EP extract from  Run 6 was  well
below the standard, however the initial concentration of
cadmium in the pickle liquor is more than 50 times lower
than the calculated concentration in  the blended waste
samples.
   Figure 5-1 can be examined  further to  evaluate the
effects of different modifications to the Soliroc process in
stabilizing  identical  blended waste  samples. The EP
extract analysis for Run 4 gave the lowest concentration
for every metal except chromium. This observation leads
to a preliminary conclusion  that either the use  of only
H2SO4 as  the acid additive or the addition of Portland
cement  improves  the stabilizing  capabilities  of the
Soliroc process. As a means of distinguishing between the
individual effects of these two process  modifications, a
                                                     74

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                                         -©— 500 t
Fig. 5-1—Concentrations of metal contaminants In EP extracts (by
experimental run number).

comparision of data from Runs 1 and 5 (duplicates) and
Run 2 yields a useful  observation. The use of either
H2SO4 (only) or pickle liquor plus  H2SO4  as the acid
additive does  not  appear to  consistently improve the
stabilizing capability of the Soliroc process. Therefore,
the use of waste acid does not adversely affect the process.
Also, the  addition  of  Portland cement appears  to
significantly improve the stabilization of certain metals.
  A comparison of the core dip analyses with the EP tests
results  yields  predictable  observations.  Metal
concentrations in the core dip samples were consistently
much lower than  those found in the EP extracts. It is
believed  that this  is  primarily  due  to  the relative
aggressiveness of the  EP  analytical  procedure when
compared  to the  core dip  experimental  protocol.
Additionally, results of the core dip analyses do not
support  the  above  stated  conclusion that  Portland
cement improves the stabilization of certain metals. The
reason for this is not understood.
  Results of the  compressive  strength tests also  yield
predictable observations and conclusions. The addition
of Portland cement in the cementation step improves the
structural stability of the hardened material.
  The results of this study  provide benchmark data  on
which  to  base  further  engineering  investigations
regarding the capabilities  of  various  stabilization  or
fixation processes. Before  more definitive conclusions
can  be drawn,  detailed experimentation  with  other
wastes, processes, and process modifications is needed. It
is suggested here that organizations such as the EPA, the
American Electroplaters' Society,  the Portland Cement
Association, and other involved with the stabilization of
potentially hazardous materials combine their efforts in
conducting  a  more  comprehensive  study  of  this
important subject.

APPENDIX A
               Pertinent References
1.  U. S.  Environmental Protection Agency, Solid and
   Hazardous Waste  Research  Division, Municipal
  Environmental Research Laboratory. Research  on
  Chemical Fixation. September, 1978.
2. U. S.  Environmental Protection Agency (MERL),
  and  Environmental  Laboratory  of  U.S.  Army
  Engineer Waterways Experiment Station. Survey of
  Solidification/Stabilization  Technology for
  Hazardous Industrial Wastes.
3. U. S. Environmental Protection Agency (MERL) and
  Environmental Laboratory  of  U.S.  Army  Engineer
  Waterways  Experiment  Station.  Physical  and
  Engineering  Properties  of  Hazardous  Industrial
  Wastes and Sludges. August, 1977.
                                                    75

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                Routes  to  Metals Recovery From
                         Metal  Finishing  Sludges
                                              Anil Mehta*
  The process wastewaters from  the electroplating
industry contain cyanides and heavy metals. Because of
their detrimental effect on the environment, discharges
are regulated  by the  federal, state, county,  or city
ordinances, thus necessitating installation of treatment
technologies. One of the treatment technologies widely in
use  already  and  more likely  to  be  installed  is
neutralization   and   precipitation  technology  which
destroys the cyanide  and removes the heavy metals as
hydroxides. This treatment is shown in Figure 1.
  The sludge is commonly disposed of in landfills. This
practice  is  coming  under  greater  scrutiny  by  the
regulating authorities, primarily due to the presence of
the heavy metal hydroxides. The heavy metals may leach
due to changes in their environment. The leached metal
may report  to the  surface  runoff waters,  or to  the
ground waters or both. To prevent any leaching of the
metals, secure and chemically maintained land disposal
sites are  required. The cost  of disposal thus becomes
greater not only because of the heavy metal presence but
also  because the secure landfill sites are expensive to
create and maintain. Finally, such sites may not become
available because  of  resentment on  the  part of  the
community itself.
  Since a landfill site has a finite capacity, sludges, in the
form generated at the electroplating plant, may not be
acceptable to the operator of the  site. Such  sludges
usually contain about three percent solids requiring
volume reduction by dewatering to conserve his capacity.
Dewatering requirements necessitate installation of a
filter press or a centrifuge. This problem from process
wastewater to the final disposal is summarized in Figure
2.
  If the landfill site is not properly maintained, certain
problems arise:
  1.  Contamination  of the  surface and  the  ground
waters by the heavy metal migration when and if the pH
conditions change.
  2.  Permanent loss  of metals  if the site undergoes a
physical change, i.e., it becomes a parking lot.
  3.  Dilution in metal contents if the sludges are mixed
with other types of waste material.
  What  makes these  hydroxide  sludges  potentially
hazardous is the presence of the heavy metals. A typical
sample composition range in shown in Table 1.
*Anil Mehta
 EPA Industrial Environmental Research Lab
 Cincinnati, Ohio
  Trying to immobilize the heavy metals in a sludge by
any one of the fixation techniques would add to the cost
of the final disposal and still promote land application of
heavy metals. Under RCRA, severe restrictions may be
encountered by land disposal.
  Recovery and recycling is  practiced by the metal
industry at significant levels. But this practice is restricted
in the sense that it applies to only the pure solid waste.
Thus, recycling constitutes about 20 percent of the total
copper metal available in the market recovered from pure
solid scrap. This is the scrap that needs simple melting
and refining. The scrap comes from two sources: capital
goods such as buildings, industrial machinery, etc., or
consumer goods such as automobiles, appliances, etc.
 SO2, NaHSO:
                              Alkaline cyanide
                              wattes with metals
                                           Ch, NaOCL
Fig. 1—Cyanide destruction and heavy metal removal.
          Process wastewater
           Treat to detoxify
    Effluent water
    to discharge
                   Sludge
Direct discharge
potentially hazardous
• Direct discharge
potentially hazardous
Fig. 2—Wastewater discharge problem.
                      Table I
         Hydroxide Sludge Composition in %*
            Copper
            Nickel
            Zinc
            Cadmium
            Chromium
2-6
2-6
2-10
2-6
5-20
            *at three percent solid contents
                                                   76

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   On the other hand, metal losses on a permanent basis
are also tremendous. Of all the recorded production of
copper in this country, 72.5 million short tons, about 60%
are traceable as being in use presently. Forty percent or
29 million  short tons  (58  billion pounds)  are lost
permanently due  to  wear,  abrasion,  chemicals,
fabrication, etc. At today's prices, this loss amounts to 58
billion dollars  figured at the price  of finished copper
product which is wire bar grade copper cathode. The loss
is staggering when figured in terms of the finished capital
and consumer goods.
   Another  example  of  this loss is provided by  the
electroless copper plating industry. The printed circuit
board   platers  comprise ten   percent   of  all  the
electroplaters in business. They generate about a million
gallons of liquid waste (sludges) annually. If one gallon of
this sludge  weighs about ten pounds and contains ten
percent copper, about a million  pounds of copper are
contained in this sludge annually. Disposal of such waste
is not always carried out with recovery at a later date in
mind, so a very significant amount is lost each year.
   The electroplaters do not treat these sludges for metal
recovery for many reasons. Recovery is an uneconomical
proposition in terms of capital and operating costs, is an
incompatible operation,  and individually the quantities
generated are not large enough to justify a  recovery
system.
   An alternative to  any  individual treatment for  metal
recovery is the concept of Centralized Waste Treatment
Facility (CWTF). Such a facility would require no  direct
participation from the platers, would pose no operating
problems to the platers,  and would  certainly solve the
discharge problem for the entire industry. By pooling it
together, the quantities to treat may be large enough to
make the recovery operation economically attractive.
   Nontreatment of these hydroxide sludges will always
present two main concerns: potential water pollution,
and  resource   loss.  With  resource  recovery  and
conservation aims in mind, any treatment to recover the
heavy metals would  alleviate the  toxic hazard problem
associated with the disposal of the heavy metals.
   Possibility of hydroxide treatment for metal recoveries
fall into  two categories: wet and dry. In wet processes,
separation  reactions  are  carried   out  usually   at
atmospheric temperatures  and  pressures.  In  dry
processes, separation reactions take place at  elevated
temperatures. The  former  processes  are  generally
classified  as  hydrometallurgy   and  the  latter  as
pyrometallurgy.
   Pyrometallurgical   treatments  for segregated  and
selected sludges are:
  • Direct recycle to a smelter after dewatering,
  • Direct recycle to metal alloy industry on a small basis.
  Troubles with pyro processes are that for economical
feasibility the operation would have to be on a very large
scale,  and that concentrated feed material is required.
The hydroxide  sludges  fail  to  meet  these   two
requirements. Under pyrometallurgical treatment, above
two above possibilities are presently available and further
discussion is not presented.
   Hydrometallurgical  treatments  for  mixed   and
segregated sludges are:
  • Aqueous dissolution of metals by leaching.
  • Recovery of individual metals or metal compounds
from this  solution.
  There  are  certain  advantages  for  using  hydro-
metallurgical processes. Metals may be won directly from
the solution by concentration, electrolysis, or hydrogen
reduction. Fuel requirements are low as the processes are
carried  out usually at low temperatures. Disadvantages
are that solution purification and  concentration  up-
grading  may  be absolutely  necessary  before  metal
recoveries are possible. But  this particular branch of
metallurgy is going to see much use as new techniques are
developed. Building mini-smelters is very uneconomical
while building  a  mini  hydrometallurgical  plant  is
becoming a matter of fact.
  Since any commercial practice would naturally take
into account the profitability as the primary objective,
the treatment  of the hydroxide sludges is being offered
with that objective in mind. This requires that the process
be specific, reproducible, and controllable. The process
should  also be possible with a minimum number of unit
operations  and  unit  processes.  The  treatment  of
hydroxide metal sludges is now considered in terms of the
unit operations and unit processes. These two depend on
the chemical state and also on the physical environment
of the metals.  Electroplating wastes, after the hydroxide
neutralization, will consist mainly of metal hydroxides
such  as Cu(OH)2,  Ni(OH)2,  Cd(OH)2,  Zn(OH)2,  etc.
With lime neutralization,  the sludge will also contain
calcium salts.  A range of composition is provided in
Table I.
  The following reagents are solvents for many minerals
and metallic constituents: sulfuric  acid, ferric sulfate,
ammonia and ammonium carbonate,  sulfur dioxide,
ferric chloride, hydrochloric  acid, and nitric acid. The
order given is about that of their importance. Metal
winning  from   solutions by  such  operations  as
cementation or electrolysis is commonly practiced from
the metal sulfate solution.
  Sulfuric acid is the most important leaching reagent.
Main advantages for its use are the cost, minor corrosion
problems, and attacking  many metal forms.  Its main
disadvantage is that it sulfatizes everything, which does
not  provide  any selectivity.  Ferric sulfate  may  be
obtained cheaply from spent pickle liquors. Its primary
function is to  provide a sulfate solution. Ammonia and
ammonium carbonate may be the most suitable reagents
for  hydroxide  sludges  because they  possess better
selectivity  for  solubilizing  metal  constituents in  a
hydroxide sludge. But the  reagent cost is very high and
their recovery in the process would be mandatory from
an economical point of view.
  Primary aim  for a solvent is to  bring the metal or
metals into solution from which individual separations
are made. This operation provides pure solutions, with
major impurities out  of the way.  For leaching,  the
following steps, as shown in Figure 3, may be necessary.
  Leaching  of hydroxides by either sulfuric acid  or
ammonia will provide lean solutions. Copper may  be
recovered from  lean sulfate solutions by cementation.
Iron will displace copper quantitatively from a solution.
The product,  although rich in copper,  may be highly
contaminated with iron so that only a smelter may be able
to handle it.  A  technique which is becoming  widely
accepted  for  concentrating  solutions is one of  ion
exchange. The ion exchange medium may be solid or
liquid.  Generally speaking,  concentrating  by solid
organic  resins  is  known as ion exchange (IX) and by
liquid organic  resin is known as solvent extraction (SX).
                                                     77

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    Solvent
                             _r
Hydroxide Sludge
                    Leaching
                    Filtration
                  Pure Solution
                Further Processing
Fig. 3—Leaching of hydroxide sludge.
                                                                   Solvent -
                                                                                     - Hydroxide Sludge
                                                                            Leaching

|
[ Filtration |
1


| Cementation | | Solvent Extraction |
Solids to
A Smelter
t k t
Solution for single metal Rest of the
Further Treatment Separation Metals
1 i
| Electrolysis
1 Further Treatment 1
                         Fig. 4—Generation and treatment of pure metal solutions.
Ion exchange saw a tremendous application in uranium
metallurgy. The solvent extraction technique is becoming
accepted in copper metallurgy. The acceptance is on such
a large scale that the future may see its application widely
spread in areas where the ore grade has kept going down
or residual metallic wastes are to be treated. The scheme
for obtaining pure solutions in Figure 3 may be expanded
now as in Figure 4.
  For sulfuric acid leach  solutions, copper may be
recovered from the polymetal solution by cementation
under oxidizing solution. The cement copper may be sold
directly to a smelter or releached for electrolysis. Other
metals are selectively precipitated after iron removal and
may be recovered as pure metals or metal compounds.
Electrolysis regenerates  the sulfuric  acid for recycle
which is a very important factor in economic evaluation
because regeneration is part of the process requiring no
additional or extra regeneration equipment installation.
  Copper may also be  removed from the polymetal
sulfate solution  by  solvent  extraction. Copper then is
removed by electrolysis. Other metal recoveries may be
                         achieved by further solvent extraction or by cementation
                         with zinc.
                           If ammonia leach is employed, metals such as copper,
                         nickel, and zinc are selectively brought into solution as
                         ammines from the hydroxide sludges. Other impurities
                         such as iron and calcium are left behind as solids. Copper
                         may be removed from this polymetal solution by solvent
                         extraction,  stripping  with  sulfuric  acid,   and
                         electrowinning.  Other metals are further  treated  for
                         separation. Additional reagent recovery equipment is
                         necessary.
                           These are two  basic routes for metal recovery from
                         hydroxide  sludges  that   have  been  looked  into
                         extensively by  various  parties.  Metal recoveries will
                         become practically feasible if the aim is to provide pure
                         solutions with a minimum number of unit operations and
                         unit processes.  A cost study was developed based on
                         sulfuric acid leach of metal hydroxide  sludges with the
                         use of solvent extraction for solution concentration and
                         electrolysis for metal recovery.
                           Generally, there are three types of liquid wastes in a
iterated
Mi
\
_ Regenerated
— *• Acid
^ t
Uach pH 1 0
I . 	
r~
fn" Adjustment
i I"
pH Adjustment



Filtration J—»- Solid. Fe(OH),, CaSO.
*

forCu
t
Electrolysis for
Cu
Cu

Regenerated
Acid
Cd Sponge
1
Electrolysis
1 	 for Cd


Solvent Extraction
for Ml
i
ElAfttrnlyklB for
NI
NI
\ i~~
F Cementation

| Filtration
1
	 J Electrolysis for
1 zr
 Fig. 5—Mixed Metal Hydroxide Sludge Recovery Process.
Table 2
Sludge Value Calculations - 3% Solids
3% Solids = gms/liter = 0.26
#/gallon
0.26#/gallon * 5%Cux$i.25/#
x 50/0 Ni x $3.0/#
* 10% Zn x $0.37/#
x 5% Cd x $3.50/#

= 0.016
= 0.039
= 0.010
= 0.046
0.111$/gallon
Sludge Sludge Wt. *
Vol. Pounds (S. T.)
Gallons @ 8.62 #/Gal.
1,000 8,620 (4.31)
5,000 43,100 (21.55)
10,000 86,200 (43.10)
25,000 215,500 (107.75)
50,000 431,000(215.50)
100,000 862,000 (431.00)
*0.26# Solids/gallon
= 0.26# solid to 1 gallon
= 0.26 + 8.36
= 8.62 ft/gallon
So//cte
Pounds (S.T.)
260 (0.13)
1,300 (0.65)
2,600(1.30)
6,500 (3.25)
13,000 (6.50)
26,000 (13.0)
water
Con-
tained
Value
111
555
1,110
2.775
5,550
11,100

                                                      78

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Table 3
Sludge Value Calculation - 20% Solids
20% Solids
= 250 gms/liter
2.13 #/gallon x
" X
" X
" X
Sludge
Vol.
Gallons
1,000
5,000
10,000
25,000
50,000
*2.13 #/gallon
= 2.13
= 2.13
= 10.5
Sludge Wt. *
Pounds (S. T.)
@ 10.5 #/Ga/.
10,500 (5.25)
52,500 (26.25)
105,000 (52.50)
262,500(131.25)
525,000 (262.50)
solids
# solid to 1 gallon
+ 8.36
ft/gallon
= 213 #/gallon

5%Cu x $1.25X# = 0.133
5% Ni x $3.00/# = 0.320
10% Zn x $0.37/# = 0.079
5% Cd x $3.50/# = 0.373
0.905$/gallon
Con-
Solids tained
Pounds (S. T.) Value ($)
2,130 (1.07)
10,650(5.33)
21,300(10.65)
53,250 (26.63)
106,500 (53.25)
water
905
4,525
9,050
22,625
45,250

                      Table 4
 Total  Contained  Values  for  10,000  Gallons  of
                    Sludge/Day
 @ 3% solids
 Total sludge weight = 43.1 S.T.
 Total contained value = $1,110
 304 working days = $337,440/year

 @ 20% solids
 Total sludge weight = 50.5 S.T.
 Total contained value = $7,220
 304 working days = $2,194,880/year

 Above values calculated with commodity metal market prices.
                      Table 5
 Fixed Capital Costs for a Leach - Solvent Extraction -
              Electrowinning Complex

                               $/Annual Ton Cu
 Leaching Facility
 SX Plant
 Electrowinning Plant
 Melting and Casting
7975

 90.7
635.0
408.2
 45.4
1,179
7980'

 182.5
1227.3
 821.1
 146.9

 2,377
 Solids @ 20% witn 5% Cu on a dry basis
 10,000 gallons/day sludge with 21,300 #solids/day
 Annual capacity=
 21,300 # solids x 5.0% Cu x 304 days x  ton = 162 tons Cu
         day                    2.000 Ib

 '15% inflation with 1975 as the base year.
plating shop: (1) rinse waters, (2) spent baths, and (3)
spills.
  Spent baths are collected separately. They require only
cyanide destruction and thus become concentrated metal
solutions.  Rinse   waters  and  spills  are  treated
                          conventionally for  heavy  metal precipitation.  This
                          presorting  provides  two distinct feed  materials:  (1) a
                          concentrated solution, and (2) a hydroxide sludge. The
                          leach solution from hydroxide  sludge leaching with
                          sulfuric acid is mixed with the spent bath solution for
                          metal extraction.  A generalized scheme  is shown in
                          Figure 5. The sludge was originally at  3 - 4% in solids.
                          Cost analysis has compared the sludge at 3% solids with
                          one at 20% solids in terms of metal values contained in
                          the product, tables 2, 3, and 4.  Fixed  capital costs are
                          provided in Table  5.
                            Annual direct operating costs for 1 ton of copper for
                          the leach  - SX - electro win complex  were $1,272 per
                          annual ton of copper in 1975. At 15% inflation rate, these
                          will be $2,560 per annual ton of copper in 1980.
                            For  162  tons   of  Cu,  annual direct operating
                          cost =  $414,720.
                            Annual indirect operating costs for 1 ton of copper for
                          the leach -SX- electro win complex were $544 in 1975. At
                          15% inflation rate, these will be $1,094 in  1980.
                            For  162  tons  of Cu,   annual  indirect operating
                          cost =  $177,228
                            Total cost of  producing copper  from  hydroxide
                          sludges  is then 2,560 +  1,094 = $3,654  per ton which is
                          about $1.80 per pound,  or a total of $583,200 per year.
                            Indirect  operating costs include costs for borrowing
                          capital,  depreciation, and income taxes, etc.
                             Total revenue from 162 tons of copper @ $1.00 per
                          pound is $324,000 per year as compared to $583,200 in
                          cost to produce it. There is a net loss in the operation
                          unless the credits from nickel,  zinc, and cadmium are
                          added to the revenues. Although their recovery will add
                          to the direct and indirect operating costs, and working
                          capital, much of this cost will have already been applied
                          to copper.
                             This  credit consideration will need  to  be examined
                          closely  before attempting to authorize  or not authorize
                          capital  spending.  Preliminary  studies show  that the
                          operation of metal recovery from the hydroxide sludges
                          would be profitable after considering  the credits to be
                          realized. There certainly is an economic  incentive for
                          treatment of the hydroxide sludges. The treatment would
                          then not be limited to the electroplating industry alone,
                          but  would  look into treating nonferrous wastes from
                          other industries too.
BIBLIOGRAPHY
Hayward, C. R., An Outline of Metallurgical Practice,
  D. Van Nostrand Company, Inc., Princeton, N.J. 3rd
  Ed., 1961.
Mehta, A., "Research Investigation of New Techniques
  for Control of Smelter Arsenic Flue Dust Wastes",
  Final Report, EPA R-804595010, April, 1979.
Bureau of Mines, United States Department of Interior,
  Minerals in the U.S.  Economy, Ten Years Supply
  Demand Profiles for Mineral and Fuel Commodities.
Pehlke, R. D., Unit Processes of Extractive Metallurgy,
  American Elsevier Company, New York, N.Y., 1973.
Bray,  J.  L.,   Nonferrous  Production   Metallurgy,
  John Wiley and Sons, Inc., New York, N.Y., 1941.
Biswas,  A.  K.  and  Davenport,  W.  G., Extractive
  Metallurgy of Copper, Pergamon Press, Elmsford,
  N.Y., 1976.
Ranchers, "Ranchers Recovers  Bluebird Oxide Copper
  by Solvent Extraction," World Mining, Vol. 22, No. 4,
  63:1969.
                                                    79

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    Solvent Recovery For the Smaller Company
                                         C. Kenneth Claunch*
INTRODUCTION
  Due to new environmental laws and the increase in
crude oil prices, as a result of OPEC, the cost of all
organics, including solvents, has risen dramatically in
recent years.  For the smaller company, this has been
particularly burdensome, since it is very difficult, as is
usual with  a smaller  company,  to pass on these
remarkable costs.
  Referring to the table below, it is a fact that in 1973
(prior to OPEC), typical solvent, in this case acetone, cost
(net) about 30c a gallon, composed of its purchase cost
and disposal cost. The latter in those days was a credit (!).
These costs have risen to the range  of $3.00 a gallon
today,  and it appears  to  be  rapidly going to $5.00 a
gallon.
                COST OF SOLVENT

         (This Example: Acetone, S per Gallon)

                1973    1976  1980 (Feb)   Projected
  Purchase
  Disposal
  Net Cost
 .35      1.35
(.05)     (.20)
 .30      1.05
2.31
.66
2.97
3.15-4.20
.66 - 2.00
3.71 - 6.20
  We are, thus approaching the day when the use of
industrial (organic) solvents is analogous to the use of
lobster at home - 'A thing of the past; too expensive!'
  Solvent recovery processes - usually an adaptation of
distillation - have been utilized for quite some time. But
these processes have been for high volume treatment of
contaminated solvents. Basically, these tend toward the
1,000  gallon/hour range  and often  involve fractional
distillation.
  Experience and  processes for treatment of smaller
volumes of solvent contamination have been  lacking.
With  price increases  and the  enormous  disposal
responsibilities facing us, recovery  of solvent, for the
small volume user, needed attention. This paper outlines
proven, successful experiences and processes for smaller
scale (one drum per week to one drum per hour) solvent
recovery systems. These processes are very economical,
often having returns on investment, ROIs, in the 100 to
400 percent range.
  During this presentation we will show you a  way not
only to save large numbers of dollars in avoiding the
purchase of new solvents, but of even greater importance,
a method to comply with the new environmental laws on
hazardous chemicals on which the  EPA is currently
issuing regulations. Solvents  contaminated  with paint,
grease, and other miscellaneous materials are identified
specifically by the EPA as "hazardous materials"* and
must be handled according to the new strict laws. The
1976 Resource Conservation and Recovery Act makes us
liable for these materials cradle-to-grave on,  apparently,
a "strict liability" basis (i.e.,  if there  is  a violation by
others, the generator is responsible 'no matter what he
did right'!). What makes this situation even more unique
is that there are fines (to 25,000/day) and a personal
CRIMINAL liability!
  Generally,  organic  liquid  wastes  fall  into  four
categories. One, oil sludges, represent about one-fourth
of the total in this country and  are not  particularly
noxious. There is the category generally called pasty
miscellaneous organic chemicals, and these cover about
one-third  of organic liquid wastes. These materials are
by-products from organic  synthesis,  still bottoms, and
the like. They are usually viscous, high boilers, and often
very toxic (e.g. Love Canal contained distillation sludge
from pesticide manufacture).  The third major category,
industrial  solvents, also represents about one-third-plus
of the wastes. We will be talking about these throughout
this presentation. The source  of contaminated industrial
solvents is many, many users - small companies  like
yourselves, and generally used for wash-up operations.
Chlorinated and nonhalogenated solvents are involved.
They are  very expensive. Their  costs  are presently
ranging from a rare $2.00 to as high as $12.00 per gallon.
The  fourth category of organic  liquid waste is of quite
well  known materials. These are pesticides, rodenticides,
PCBs,  and other particularly noxious and/or  well
publicized**  toxic  chemicals.  This fourth  category
represents only  1 to 2 percent of the U.S. organic wastes
total.
SOLVENT RECOVERY WITH STANDARD STILL
(Nominal rate: 4 drums j shift)
How it works:
   This batch type solvent recovery technology is the not-
new  method of differential distillation combined  with
recently developed techniques to allow the controllable
boiling and removal of valuable solvents from residues
that  can range in viscosity up to 10,000 CPS.
   Basically the still operates by heating contaminated
solvents to form vapors of  pure solvents, condensing
*C. Kenneth Claunch
 Finish Engineering Company, Inc.
 921 Greengarden Rd., Erie, Pennsylvania 16501
                                                   80
                                         Federal Register, Vol. 43, No. 243, p. 58957, 250.14 (a).
                                        * Publicity often increases the perceived toxicity of a chemical, which,
                                         in essence, makes it more toxic from a regulatory standpoint!

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them outside the still to collect a clear, purified solvent
mixture. The difficult aspect of this operation is that the
residue in the still is becoming more and more viscous.
The gist of the technology of this  still  is (1) to have
instruments that can readily alert the operator when the
viscosity or  thickness  of the  residue in the still is
beginning to increase. In lay terms, we want to continue
to  boil  the  material  until the  residue is about  the
consistency of catsup and not go as far as the consistency
of peanut butter.
  The viscosity instrument is quite simple  and non-
plugging (very, very important when dealing with such
thick medias). When the material is too thick, shut-down
is automatic.
  It is also essential (2) to have a means of eliminating
caking on the heated wall. A patent pending device that,
in essence, scrapes the  wall with a  non-wearing, non-
sparking razor-blade-like knife  every five seconds is
utilized. Heat transfer coefficients of over 200 Btu/ hr-ft3 -
0 F can be maintained even to viscosities of over 5,000
centipoise.
  Figure 1 shows a flow diagram of the still. (A) is the
boiling chamber into which the contaminated solvent is
pumped. Heat is supplied from a boiler at (E) to the steam
jacket at (B). The internal scraper is indicated by (D). The
vapors of solvent(s) exit the unit at the top and are
condensed by an air cooled or water cooled condenser (C)
filling the clean solvent drum  to the  left. The highly
reliable controls at (E) tell the operator that his viscosity
is satisfactory.
  In actual operation the operator  does the following:
Into an empty still he pumps two  55-gallon drums of
contaminated solvent. He turns on the still and then can
leave the area. The unit will boil and condense one drum
and shut itself off. When the operator returns, he pumps
in another drum of contaminated solvent and places an
empty clean drum under the condenser. Again, he turns
on  the  still and  leaves the area. Typically, this  will
continue until 10 drums have been added and nine drums
of clean solvent(s)  recovered, a 90% recovery.  The
remaining one drum residue is drained out the bottom of
the still into a sludge drum. This sludge can be disposed of
by EPA approved  methods (e.g. certain landfills) or by
processing it  in a  manner to be discussed later in this
presentation.

Economics
  The return on investment from this  process is often
startling. If a company has JUST one drum per day of
contaminated solvent, the return  on investment (ROI)
Figure 1—Flow Diagram, Standard Still.
                                                     81

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will be approximately 100%, a one year payout! It is very
common that many users have ROIs of 200-400%. One
user in Indiana has been operating his still for 3 years at
28  gallons/hour,  24  hours/day,   5 days/week.  He
processes 14,300 gallons/month with a yield of 93%.
Using a minimal cost of this ketone of $2.00+ per gallon,
his savings currently amount to approximately 1/3 of a
million dollars jjer year, for a low 5-figure investment.
Fig. 2-Recovery Still.
   Another  example  is  a  still at  GTE-Sylvania  in
Tennessee.  See  Figure 2.  This  still is nearly 100%
automatic, being fed from an underground tank and the
clear recovered  solvent  flows  by gravity to another
underground tank—labor input is nominal. The engineer
in charge is quoted as follows:
   "Our still extends the life of our acetone tremendously.
With the exception of losses through process evaporation
and sludge collection, we are able to use the same acetone
for a minimum of six cycles.  This solvent life extensions
has decreased our cost per gallon from $ 1.45 to about 30c
which includes our cost of operating the reclaimer.
   In addition  to this bulk reclaiming operation, we are
enjoying further savings  by reclaiming  thousands  of
gallons of drummed acetone and alcohol collected during
prior years. By reclaiming we return it to the drum and
use it over and over.
  "The combination of savings, which in total exceed
$50,000  a  year,  the  peace  of  mind   from  virtual
independence from outside solvent availability, and our
compliance  with tough new hazardous waste disposal
standards makes in-house solvent reclaiming a great
addition to our operation."

SOLVENT RECOVERY WITH STEAM/IN SITU
(IN DRUM) DISTILLATION
(Nominal Rate: one drum/shift)

How it works:
   This process works by distilling the solvents directly
out of the drum to a condenser for collection. Leaving the
material in its drum is a real advantage since many drums
cannot be pumped out completely (in some cases, not at
all). Further, if the goal is to remove all solvents (as in the
case in this process), the final non-volatile material will be
a rock or sand-like 'mess' - best left in a disposable drum
rather than in processing  equipment causing, perhaps,
costly clean-up.
  The distilling is done by a special  method (patent
pending) of steam injection safely into the contaminated
liquid or sludge in the drum. As a result, the condensate is
both water and solvent (in most  cases the solvent is
immiscible in water, therefore, easily separated.  If the
solvent  is miscible  with  water—very few are—this
process is not applicable).
  The drum of material can, of course, be the viscous
residue from the previously discussed (still) operation, or
in the case of a very small usage, from the user's process.
This is to say, if a company only has one drum per day or
one drum per week,  this process would be economical
and recommended.
  The operating  sequence is as follows: The drum is
placed inside a special insulated cabinet. The band steam
heater (part of the cabinet) is closed around the drum. A
very special  (but inexpensive) steam sparger  line is
inserted into the drum through the smaller bung opening
in the top of the drum and  connected by a flexible line to
the controlled steam line. The larger (2") bung opening is
connected by a flexible line that goes to the condenser. By
simple temperature control the following occurs: The
liquid is heated to the boiling temperature by the steam
jacket, so called  "dry heat."  This temperature  is the
azeotropic boiling point of the solvent-water mixture
that will  exist  inside the drum  (due to  some  water
condensation in the drum). For example, if the solvent
was  toluene  (normal boiling point  of  231°  F) the
azeotropic boiling temperature is 185° F. It will always be
less than the boiling point of water, 212° F - no matter
what  solvent is in the drum. This is a real advantage,
allowing the recovery of even  high boilers, 300-400° F
range, with just steam.
  When at this azeotropic boiling point, the steam to the
sparger is activated and the steam enters the liquid in the
drum by the special sparger. Two phenomena occur: (1)
part of the steam strips the solvent into vapor which exits
the drum; and  (2) of critical importance, the steam, if
properly sparged into the liquid, will cause heat transfer
into the whole mass rather than just to localized areas of
the sludge causing  caking and  slowing  of the heat
transference which would  nullify the entire process.
  This is  the gist of this  technology. To explain: The
contaminated solvent will start, perhaps, as fluid and
become thicker and  thicker until it reaches an infinite
viscosity (!), i.e. it ends up as a solid. Thus, one would ask
how the heat is effectively transferred to this extremely
thick material towards the end of the process. The answer
is that the water,  condensed due to earlier heat transfer
(discussed above), is the heat transfer media to the final
solid  contamination.  In a typical, properly operated
situation, there will be about 10 gallons of water in the
drum at the end of the solvent stripping.
  The steam and solvent vapor enter a condenser, similar
to the  condenser on the still discussed  earlier,  and
condenses. A simple two-layer separation tank removes
the condensed water from the condensed liquid solvent.
  At the end  of the operation  the  temperature will
rapidly rise from  the boiling temperature up to 212° F,
the boiling point  of water, indicating there is no solvent
                                                    82

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Fig. 3-Solld Residue.

left. At this point, the steam to the sparger stops. The dry
heat (jacket) continues until the water is boiled away.
  After this operation, the  drum is removed from the
cabinet. The top of the drum is cut off.  The toxic, non-
volatile contaminants,  often looking like rocks or sand,
that  remain are  pulled  out  of the drum with  the
disposable steam  sparger. This solid material can  be
disposed of by safe, legal methods, usually directly to an
approved landfill.
  Figure 3 shows the solid residue from this process. This
is a dramatic picture, in that it represents the solid, non-
volatile toxic materials that originally  (before both
processes  described herein) were  contaminated with
about  800 gallons  of solvent! That is, the processes
yielded about 770 gallons of pure solvents and this 'rock';
good  from a hazardous  wastes  and  an  economic
standpoint.  The  disposable sparger pipe can  be seen
sticking out of the top of this 'rock'. The bottom of the
rock, you  will  note,  conforms to the inside of a 55-gallon
drum,  i.e.  the  bottom of the rock is 22" in diameter (to
give the reader a  dimensional reference).

Economics:
  The  economics are very similar to the still discussed
above. The return on investment (ROI) ranges from 75 to
300%.  Investment is just at the 5-figure range.
  Labor input required is essentially nominal since  the
operation  is automatic once the drum is put into the unit.

CONCLUSION
  The 1976 Resource  Conservation and Recovery  Act
states:
     "(c) Materials  - The Congress finds with respect to
         materials, that—
        "(1)  millions of tons of recoverably material
              which could be used are needlessly buried
              each  year;
        "(2)  methods  are available to separate usable
              materials from solid waste;  and
        "(3)  the recovery and  conservation  of such
              materials can reduce the dependence of the
              United States on foreign  resources and
              reduce  the  deficit  in  its  balance  of
              payments."
  We  have revealed in this presentation high viscosity
distillation processes that have the capability to recover
materials just  as Congress dictated above.  Distillation is
rarely  thought of as a waste treatment process. But, in
fact, it is one of the best, yielding recyclable materials (as
solvents, discussed  herein) or clean liquid condensates
that can be incinerated without resultant  toxic fly-ash-
like solids in the  effluent gas. Distillation  energy cost is
minimal, only about 2c to 3c per gallon, relative to the
high value of the recovered material  and/or the high
value of avoiding hazardous solvents.
  The specific processes discussed for industrial organics
(solvents,  etc.) in  drum quantities allow  economical
recovery  and, also,  waste elimination for even  the
smallest company.
                                                      83

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           VOC  Incineration  and Heat  Recovery -
                         Systems  and Economics
                                           Roy M. Radanof*
INTRODUCTION
  Volatile  Organic  Compounds  (VOC) from
metal finishing operations must be controlled to  help
preserve our nation's clean air standards. While many
metal finishers have converted to formulas with reduced
or  no  VOC,  many  others  have   chosen  add-on
incineration as a means of VOC control.
  Two  types of  incinerators  are  available  for air
pollution control,  thermal and catalytic units. Thermal
incinerators consist of a volumetric enclosure  through
which solvent laden discharge air  mixture from curing
ovens passes. A fuel source, usually natural gas or No. 2
fuel oil, is used to raise the temperature of the air stream
to 1200 to 1400° F. At this temperature, most of the VOC
(solvent) is destroyed by.oxidation. The final emissions
contain CO2, water vapor,  N:, air and  traces of the
original solvent.
  The solvent  destruction  efficiency  of  thermal
incinerators is dependent upon the retention time of the
solvent  at  the   control   temperature,  the  control
temperature itself, and the degree of turbulence within
the incinerator. VOC destruction efficiencies of greater
than 90 percent are common with these units.
  Thermal incinerators are easily controlled and usually
have built-in bypass dampers around the primary heat
recovery unit to facilitate process variations.
  Catalytic  incinerators  are  similar   to   thermal
incinerators, except  that a catalyst has been added to
enable the solvents to oxidize at  a significantly lower
temperature than in thermal units. Catalytic incinerators^
have a preheat section at the inlet in which fuel is added to
raise the waste air temperature to the minimum  required
for the oxidation reaction to take place on the catalyst
surface. As  the  solvents oxidize, additional heat is
released, thus promoting the destruction of solvents. The
final temperature achieved in the  oxidation affects the
destruction efficiency of the unit in addition to life of the
catalyst. Catalytic incinerators can usually achieve the
same destruction efficiencies as thermal units; however,
they are more limited in their applications to process
conditions.
  The addition   of either  a thermal  or   catalytic
incinerator  for  the  destruction  of VOC will usually
accomplish the environmental objective of air pollution
control; however,  if proper engineering analyses of the
total plant conditions are not conducted, the plant can be
severely penalized with excessive operating fuel costs. On
the other hand, a thorough and comprehensive analysis
of the total plant can result, in many cases, in the
incinerators being operated at no energy penalty or can
even  achieve a net  energy savings  for the  plant as
•Roy M. Radanof, PE
 CENTEC Corporation
compared to energy requirements before the incinerator
was installed.
  This paper highlights fuel requirements, heat recovery
options and economics  of operating  both types  of
incinerators. The energy benefits that are possible will
provide  economic incentives  for  plants  to  install
incinerators as  a means of achieving the environmental
objective of air pollution control. The DOE Technology
Applications Manual entitled, "The Coating Industry:
Energy  Savings   with  Volatile Organic  Compound
Emission  Control,"  TID-28706, published  in   1979,
provides in-depth analyses of the concepts highlighted in
this paper.

WHICH TO SELECT: THERMAL OR CATALYTIC
INCINERATION
  One of the  most  common questions  asked  when
implementing an add-on incinerator is: "Which is better,
thermal or catalytic?" Unfortunately, the answer is: "It
depends on the site conditions."
  The environmental objective is the same for each—to
achieve  a  high  solvent  destruction  efficiency  that
complies with regulatory standards. Without studying
the overall plant conditions, the "best" choice cannot be
determined.  A brief review  of the advantages and
disadvantages of  both types  of systems will highlight
some of the considerations.

ADVANTAGES OF THERMAL INCINERATION
  Thermal incinerators  can  usually  achieve  solvent
destruction  efficiencies  greater  than  90 percent.
Efficiencies as high as 97 to 98 percent are obtainable on
newer units. Thermal incinerators  can be used with a
wide  range  of applications.  Particulates and  resins
usually  are destroyed  with  the  solvents. Thermal
incinerators  are  insensitive to  solvent  concentration
variations. Because of their high operating temperatures,
there  is a  high heat  recovery  potential. Thermal
incinerators can operate with  solvent concentrations up
to 50 percent  of the Lower Explosive  Limit  (LEL),
providing the proper  instrumentation and controls are
employed to comply with the National Fire Protection
Association codes and standards. Fuels consist of natural
gas, oil, or propane.

DISADVANTAGES  OF  THERMAL  INCIN-
ERATORS
  Thermal incinerators have a potentially high operating
cost  primarily due to energy  consumption. A  large
volumetric air  flow rate is heated from temperatures
typically at 200-300°  F to 1200-1400° F. Without heat
recovery, the exhaust gases carry away millions of Btu
which are lost to the atmosphere. Since retention time is
important  for   destruction  efficiency,  thermal
incinerators are large, sometimes posing siting problems.
There is no solvent recovery with thermal incinerators;
                                                  84

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however, the solvents usually contribute a substantial
fuel value to the operation of the incinerator. The heat
provided by the solvent during oxidation reduces the
incinerator fuel requirement by an equivalent amount of
heat.  This  is an important  concept in  estimating the
energy requirements for incinerator operation.

ADVANTAGES OF CATALYTIC INCINERATION
  Like thermal incinerators,  catalytic incinerators can
usually achieve the same solvent destruction efficiencies.
Catalytic  units  can  handle  multisolvent   mixtures,
providing these  mixtures were considered during the
design and specification of  the  catalyst  materials.
Without considering heat recovery, catalytic incinerators
have a significantly lower operating cost in terms of fuel
expense than thermal incinerators. In the preheat section
of a catalytic unit, waste air is heated from 200-300° F to
550-900°  F. This  temperature rise is lower  than that
required for a thermal unit performing the same duty.
  The final exhaust temperatures from catalytic units
usually  range  from 900 to  1200°  F.  This exhaust
temperature has high heat recovery potentials  for use
elsewhere in  the  plant  or  for reducing the cost of
incinerator operation  as will be  illustrated shortly.
Retention time is not so important with catalytic units as
with  thermal  units; therefore,  the  units are  usually
smaller than thermal units for equivalent air flows.
  The temperatures referenced in the discussion so far
are for a wide variety of applications. Many vendors have
catalyst materials that operate effectively at temperatures
significantly different from those referenced and can have
equally significant effects on energy consumption. This is
another factor for consideration in selecting the best type
of incinerator for a site specific condition.

DISADVANTAGES OF CATALYTIC INCINERA-
TORS
  Catalysts are limited to the number of applications in
processes  since some waste air streams may contain
catalyst poisons such as phosphorous,  bismuth, lead,
arsenic, antimony,  mercury, iron oxide, tin, silicon and
others. These poisons cause irreversible reduction of the
catalyst activity at a rate dependent on concentration and
temperature.  Excessively high temperatures also  will
deactivate the catalyst in a shorter period than its normal
life.  While higher temperatures  will provide  greater
destruction efficiency, catalyst life will be decreased and,
consequently, maintenance costs  will  rise. Particulates
and resins must periodically be cleaned from catalysts to
reduce plugging and to maximize available surface area
for  reactivity. Like thermal incinerators, solvents are
destroyed and are unavailable for recovery. Catalytic
incinerators are  more limited  in  fuel options than are
thermal incinerators. Usually,  natural gas is used as the
fuel  source. Oils containing sulfur can  influence the
catalyst activity by  placing a reversible surface coating on
the active area of the catalyst. Catalysts are expensive to
replace.  Some  plants  considering  using  catalytic
incineration might have to precondition their waste air
stream to prevent problems with the catalyst.

REDUCTIONS OF  INCINERATOR  FUEL CON-
SUMPTION
  Several years ago, when energy was less expensive and
more plentiful, heat recovery was not normally included
with incinerators;  and  plants  purchased  equipment at
minimum capital expenditure. Today, plants can justify
additional  capital   outlays   for   reducing  energy
consumption by lowering air flows to increase solvent
concentration, and by including heat recovery options.
LOWER  AIR FLOW TO  INCREASE  SOLVENT
CONCENTRATION
  The NFPA,  Code  86-A,  "Ovens  and  Furnaces,"
describes conditions under which solvent concentrations
must be kept below 25 percent of the LEL and those in
which concentrations may approach 50 percent of the
LEL.  This  paper addresses the  conditions  below 25
percent of the LEL since this is the area where  the
majority of the metal finishers presently operate.
  The NFPA provides two methods of calculating the
solvent concentration  in terms of percent of the  LEL.
One method referred to as the "general method," is based
on using 10,000 cubic feet of dilution air at 70° Fforevery
gallon of  solvent  evaporated to  achieve a  solvent
concentration of 25 percent of the LEL. This provides a
convenient  calculation for approximation,  but it is
usually conservative in specifying needed  dilution air
flows. Since the fuel input to the incinerator, as well as the
oven, is determined by the energy required to heat the air
flow rate to a specified temperature, any reduction in the
air  flow  will  lower  the  fuel requirement. This,  then,
becomes an objective for energy reduction and can be
accomplished by following the second NFPA calculation
method.
  The second method allows the solvent concentration to
be determined by actual consideration of the solvent
composition and properties. It is more rigorous than the
first method,  but it usually results in  less  dilution air
requirements.
  For example, Figure 1 shows solvent removal rates at
25 percent of the LEL. If Methyl  Ethyl Ketone (MEK)
were evaporated at 60 gph, then 10,000 scfm of dilution
air would be required usfng the "general method."  If the
actual LEL  of MEK was considered, then the required
dilution air  would be  approximately 45 percent lower
than using the general method. The fuel effect of this air
reduction will be  seen shortly.
  Typically, metal finishing operations are performed at
solvent concentrations  in the 7 to 10 percent of the LEL
range with many falling as low as  1 to 2 percent of the
LEL. If these solvent concentrations were increased to 20
 PROCESS
AIR FLOW  10
(THOUSANDS
 OF SCFM)
                        10,000 SCF AIR PER GALLON OF SOLVENT


                                            I
                       Bo     120     160
                      SOLVENT REMOVAL RATE (GPH)
Fig. 1—Solvent removal rates at 25 percent of the LEL.
                                                     85

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 PROCESS AIR FLOW
(THOUSANDS  OF SCFH)
                        20    40    60    80    100   120
                         SOLVENT REMOVAL RATE  (GPH)
 Fig. 2—Air flow requirements for solvent removal rates.


T,
X


X
PRIMARY S
HEAT RECOVERY
T2>

THERMAL OR
1 NC 1 NEBATOR


T,

 Fig. 3—Typical primary heat recovery.
 INCINERATOR NATURAL GAS
REQUIREMENT  (MILLIONS OF
 BTUH PER 10,000 SCFM)
                             	THERMAL INCINERATOR

                             	CATALYTIC  INCINERATOR
                   200   ^ 00   600   800   1000   1200  1*<00

                      INLET TEMPERATURE TO INCINERATOR  (°F)

Fig. 4—Energy required for thermal and catalytic incineration without heat
recovery.
to  25 percent,  the reduced  air heating loads would
conserve considerable fuel.
   For example, Figure 2 illustrates air flow requirements
for different solvent removal rates. It is based on using
the general method of 10,000 cubic feet of dilution air per
gallon of solvent evaporated. An oven operating at 60
gph solvent removal rate and at a solvent  concentration
of  10 percent of the LEL can have its air flow reduced
from  25,000 to 10,000 scfm  by  increasing its  solvent
concentration to 25 percent of the LEL. This results in
60 percent air flow reduction.
 INCREASE  INLET AIR TEMPERATURE TO IN-
 CINERATOR
   In addition to lowering the dilution air flow, the inlet
 air temperature to the incinerator  can be  increased
 through  primary  heat  recovery  to  reduce fuel
 requirements. Figure 3 illustrates a typical primary heat
 recovery application. The hot incinerator exhaust gases
 at  temperature T? are recycled to  a primary heat
 exchanger where they raise  the oven waste air stream
 from temperature Ti to T2. The exhaust gases are finally
 released to the atmosphere at temperature  T4  or can be
 further used as a secondary heat source.
   Figure  4 shows the  combined effects of reduced air
 flows   and   increased   incineration   and/or  inlet
 temperatures  on  fuel  consumption  for thermal and
 catalytic units. This figure is specific to the conditions
 shown  below;  however,  it  is  illustrative  for  similar
 process conditions.
   The basis for Figure 4 is given below:
   1. Solvent is toluene (catalytic ignition temperature is
 575° F with particular catalyst considered)
   2. Natural gas HHV = 1100 Btu/scf
   3. Thermal incinerator operating temperature = 1400°

   4. Catalytic incinerator exhaust temperature = 1000°
 F
   5. HHV of toluene = 4484 Btu/scf
   6. 95 percent destruction efficiency of toluene
   7. LEL of toluene =  14,000 ppm
   8. No heat  losses
   9. Waste stream air  from  oven  exhaust  used  as
combustion air in incinerator
   First, the fuel requirements for thermal and catalytic
units  can  be compared for the  same  given process
conditions. For example, at  an inlet temperature to a
thermal  incinerator of  400°  F  and with a  solvent
concentration of 15 percent of the LEL, the natural gas
requirement is 8 million Btu/hr/10,000 scfm of process
air flow. Under the same process conditions, if a catalytic
incinerator were used, the natural gas requirement would
be 2.3  million Btu/hr/10,000 scfm of process  air. A 71
percent fuel reduction  is experienced  with the catalytic
unit as compared  to the thermal  unit, both operating
without heat  recovery.
   To  illustrate the effects of  reduced  air flow, consider
the thermal incinerator now  operating at 15 percent of
the LEL and with an inlet air temperature of 400° F.  If
the air flow were reduced to achieve  25 percent of the
LEL, the natural gas requirement would decrease from 8
million to 4.4  million Btu/hr/10,000 scfm of process air
flow. Combining the reduced air flow  with primary heat
recovery so that the new inlet  air temperature  to the
thermal  incinerator  is  600°  F,  the  natural  gas
requirement   is further  reduced  to  1.5   million
Btu/hr/10,000 scfm of process air flow. Thus, a process
air flow of 20,000 scfm adjusted to the above conditions
would  require 3.0 million Btu/hr of natural gas [(20,000
scfm/10,000 scfm)  X 1.5 million Btu/hr] to achieve  a
solvent destruction efficiency  of 95 percent. The goal is to
establish  the  highest  possible  solvent  concentration
allowed  by  NFPA  standards  and  to achieve  the
maximum possible heat recovery to minimize incinerator
fuel requirements.
   There are several important considerations to keep in
mind. All  VOC have an autoignition temperature where
oxidation takes place. In recuperative type shell and tube
heat exchangers, tube failure could occur if the solvent is
                                                      86

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allowed to reach its autoignition temperature inside the
exchanger. It is, therefore, a good practice to limit the
waste air preheating to a maximum temperature of 100°
F below the solvent's autoignition temperature.
  In regenerative type heat exchangers, such as stone
beds and ceramic wheels,  autoignition is not usually a
problem,  and  higher  preheat  temperatures can be
achieved.
  Another consideration is that for every percent of the
LEL  of the solvent present,  a  temperature rise  of
approximately  27.5°  F is experienced for 100 percent
destruction efficiency of  the solvent. All incinerators
have a  maximum design  operating temperature which
should not be exceeded; otherwise, equipment damage
might occur. If this temperature were  1500° F, then care
must be taken in sizing the primary heat recovery unit so
that the preheat temperature, when combined with the
temperature rise from the oxidation of the solvent, will
not  exceed  1500°  F.  For example, if the  solvent
concentration were 15 percent of the LEL and the preheat
temperature were 800° F, then  the resulting  operating
temperature would be approximately 1488° F which is
below the  maximum design temperature.
  The  same  considerations apply to  catalytic units.
Figure 5 shows the combined  effect of inlet and outlet
temperatures  of  catalysts for  90   percent  solvent
destruction efficiency. This figure is for one particular
solvent/catalyst  combination;   however,   it  is
representative for other combinations  if the temperature
were adjusted.
  The upper curve is  the exhaust temperature from the
catalyst. From 0 to 15 percent of the LEL, the curve is flat
at 1000° F. This  is the  minimum exhaust temperature
that will result in 90 percent destruction for the particular
solvent.
  The   lower   curve  represents  the  required  inlet
temperature  to  the  catalyst  at the given  solvent
conditions  that  will  result  in  the  required  outlet
      1»IOO


      1300


      1200

 u.
 °_,    noo

 UJ

 =    1000
 <
 a:
 Ul
 I     900
 uj
 H

       800



       700


       600


       500
         PROCESS
       MINIMUM EXIT TEMPERATURE
       FOR 90* CONVERSION
       —MINIMUM CATALYST •
        ACTIVATION TEMPERATURE

             I      I
                               TYPICAL REQUIRED
                               INLET TEMPERATURES
                               TO CATALYST (T
                                          c.)  -
I
Fig
      0      5      10      15     20      25     30

          SOLVENT CONCENTRATION (PERCENT OF LEL)

5—Catalyst temperatures at 90 percent solvent destruction efficiency.
              temperature. For example, in the solvent concentration
              range of 0 to 15 percent of the LEL, it will be necessary to
              add supplemental fuel to the incinerator preheat section
              or to  utilize  primary  heat  recovery  to  achieve  the
              minimum  inlet temperature shown.  If  the solvent
              concentration is at 10 percent of the LEL, then the waste
              air stream will have to be heated to  about 700° F before
              entering the catalyst. The fuel value of the solvent will
              result in the final temperature rise to the required  1000°
              F.
                 Above  15 percent of the LEL, the effect is different.
              Since the catalyst has a minimum reactivity temperature
              that must be achieved to start the oxidation process, it is
              not possible to enter the catalyst below this activation
              temperature. In Figure 5, the reactivity temperature  is
              575° F. If the solvent  concentration is greater than 15
              percent  of  the  LEL,  then  the  resulting  exhaust
              temperature will exceed the 1000° F and will seek a level
              depending on the exact amount of  solvent present. For
              example, if the solvent concentration were at 20 percent
              of the LEL, then the minimum reactivity temperature
              would be achieved either by primary heat recovery or
              supplemental  fuel.  The solvent's  heating value and
              quantity would increase the exhaust temperature  to
              about  1130°  F.  At this temperature, the destruction
              efficiency is improved;  however,  it  is a more severe
              condition for  the catalyst.
                 In quantifying the amount of primary heat recovery to
              be used, the most common practice is to use the term
              "percent heat  recovery."  Percent heat recovery is a ratio
              of the amount of heat recovered to the amount of heat
              that is available for recovery. Commonly, it is expressed
              as a temperature ratio as  shown in Figure 6, since the gas
              flows to and from the incinerator are assumed to be equal
              through the heat exchanger if external combustion air is
              not added to  the incinerator. There is a more rigorous
              definition of percent heat recovery based on enthalpies;
              however, the temperature ratio will be sufficient for most
              purposes.
                 Figure 7, shows the limits of primary heat recovery for
              thermal incinerators. A similar figure can be constructed
              for catalytic  incinerators.  Figure  7,  is based on  the
              following conditions:

                 1. Incinerator exhaust temperature = 1400° F
                 2. Solvent is toluene having HHV = 4484 Btu/scf and
              LEL = 14,000 ppm
                 3. Shell and tube  heat exchanger limit includes a 100°
              F safety factor below autoignition temperature of toluene
                                                             COLD STREAM
                                                           FROM OVEN (T- }
                                                    HOT STREAM TO
                                                    INCINEftATOR (T )
                                    INCINERATOR (T )
              Fig. 6—Percent Heat Recovery.
                                                                                                          - T

                                                                                                          - T,
                                                     87

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MAXIMUM  USABLE
   PRIMARY
HEAT RECOVERY
  (PERCENT)
90


80


70


60


50


1*0


30


20


10
                                         5* OF LEL
SHELL AND TUBE
HEAT EXCHANGER
    LIMIT
                 200  ^00   600  800  1000  1200

                     OVEN EXHAUST TEMPERATURE (°F)

Fig. 7—Limits of Primary Heat Recovery for Thermal Incinerators.
  4.  100 percent destruction efficiency of toluene
  5. Autoignition temperature of toluene = 997° F
  6. No heat losses
  7. Waste  stream  air from  oven  exhaust used  as
combustion air in incinerator
  So as not to  encounter autoignition damage in the
primary heat exchanger, shell and tube units should be
applied only to the conditions represented by the shaded
area. Regenerative units not susceptible to autoignition
damage can be operated in the shaded or unshaded areas.
  For example,  an oven that exhausts gases at 600° F
and at five  percent of the LEL for toluene will allow a
maximum usable primary heat recovery of 82 percent for
those heat  exchangers  not susceptible to autoignition
damage. Because the temperature limitation is 897° Ffor
shell and   tube  heat  exchangers with  toluene,  the
maximum   heat  recovery  achievable at this solvent
concentration would be only 36 percent to prevent
autoignition damage. At five percent of the LEL toluene
concentration and with maximum usable heat recovery
for shell and tube exchangers, the gases would leave the
exchanger at 897° F (as read at  the intersection of the
limit curve with  the  horizontal axis), and auxiliary fuel
would be required to raise the temperature from 897° F
to 1250° F  (intersection of 5 percent of LEL curve with
horizontal  axis). The fuel value  of the toluene would
provide the  heat  necessary in going  from 1250° F to
1400°  F. If a heat  exchanger could  operate with  82
percent  heat  recovery,  the  gases  would  exit  at
approximately 1250° F and auxiliary fuel flow would be
negligible.
  It  is important when  purchasing  a primary  heat
recovery unit to know that it is possible to use the level of
heat that the equipment is capable of recovering.

SECONDARY HEAT RECOVERY
  Secondary heat recovery is the utilization of the heat in
the incinerator exhaust gases for any purpose other than
                                                                               WASTE HEAT BOILER'
                                                                                              PROCESS STEAM
                          Fig. 8—Secondary heat recovery with a waste heat boiler.
                                                          Fig. 9—Secondary heat recovery with direct gas recirculation.
                                                                           OUTS IDE
                                                                             Al R


OVEN






<
<;


PREHEATED AIR |
SECONDARY USER

                                          Fig. 10—Secondary heat recovery with indirect heating.
                                           preheating the inlet air to the incinerator (primary heat
                                           recovery). Figures 8, 9, and 10 illustrate three common
                                           applications of secondary heat recovery.
                                             Figure 8 shows a waste heat boiler that is driven by the
                                           hot  exhaust  gases from a  thermal incinerator. Low
                                           pressure  process  steam  is  generated  for  utilization
                                           elsewhere in the plant for process or building heating.
                                             Figure 11 is based on generating 40 psig saturated
                                           steam and shows steam capacities and fuel savings using
                                           waste heat  boilers. The exhaust from the waste heat
                                           boiler is set at 450° F and an 85 percent boiler efficiency is
                                           assumed. Feedwater  is set at 200°  F,  and natural gas
                                           having a HHV of 1100 Btu/scf is used  as the energy
                                           source for comparative fuel savings to a package boiler.
                                             For example, a waste heat boiler operating with an
                                           inlet temperature of  1000° F with 10,000 scfm and an
                                           exhaust temperature  of  450°  F  will generate  6,400
                                           pounds/ hour  of 40 psig saturated steam. This will save an
                                           equivalent of 8 million Btu/hr of natural gas inapackage
                                           boiler to generate the  same quantity of steam.
                                             Figure 9 shows the direct  mixing of recirculated
                                           exhaust gases with fresh outside air going to the oven.
                                           The  preheating  of the oven  supply air significantly
                                           reduces the fuel requirement for the oven. Care should be
                                           used in operating this type of system to assure that the
                                           solvent concentration in the oven does not creep up due
                                           to a malfunction of the  incinerator in destroying the
                                           solvents.
                                             The  indirect heating of oven supply  air,  shown in
                                           Figure 10, prevents recirculating any solvent vapors by
                                                      88

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            I MOO


            12,000



            10,000
 STEAM GENERATED 8'000
 PER 10,000 SCFH
 PROCESS AIR FLOW
    (LB/HR)    6,000
            4,000
            2,000
'   NATURAL GAS
    SAVINGS
 (MILLIONS OF BTUH)
               500   700   900   1100   1300  1500

         EXHAUST GAS TEMPERATURE ENTERING WASTE HEAT BOILER (°F)

Fig. 11—Steam capacities and fuel savings of waste heat boilers.
employing an air-to-air heat exchanger with separate air
paths.
   A "net energy savings" for the plant is only possible
using secondary heat recovery. A net energy savings is
accomplished  by putting the  heat  released  from the
oxidation of the solvents to work. Many solvents have
heating values that are 4 to 5 times greater than those of
natural gas. If suitable heat sinks are available to utilize
this heat, then the economics of the heat recovery options
should be explored to determine the value of investments.
   Figure 12 illustrates  both the energy  required  and
recoverable using thermal incinerators with secondary
heat recovery. A similar figure can  be developed for
catalytic  units. Figure  12 is  based  on the  following
assumptions:
   1. Thermal incinerator operating at 1400° F
   2. No primary heat recovery - secondary recovery only
with waste heat boiler
   3. 85 percent boiler efficiency assumed
   4. Solvent is toluene (HHV = 4484 Btu/scf)
   5. Fuel is natural gas (HHV = 1100 Btu/scf)
   6. Waste stream  air  from  oven  exhaust  used  as
combustion air in incinerator
   For  example,  if the inlet temperature  to a thermal
incinerator were 500°  F, the natural gas requirement of
the incinerator is 6.6 million Btu/hr/10,000 scfm process
air flow for a solvent concentration of 15 percent of the
LEL of toluene (See point W). At a  waste  heat  boiler
exhaust   temperature   of   500°  F,   10.6  million
Btu/hr/10,000 scfm process air flow  (point X) will be
transferred for the production of steam. This amount of
energy  being  transferred  would  save  12.2 million
Btu/hr/10,000 scfm process air flow  of fuel (point Y).
The plant achieves a net energy savings of  5.6 million
Btu/hr/10,000 scfm process air flow (12.2 - 6.6 million
Btu/hr)  if a  use for  10.6 million Btu/hr/10,000 scfm
process air flow could be found. The waste heat boiler
would  save 6.6 million Btu/hrlO,000 scfm  process air
flow (the same energy as consumed in the incinerator) if
the secondary  heat  recovery unit exhausted at 920°  F
(point Z). A catalytic unit, with a secondary heat recovery
unit exhausting at 500°  F would recover  5.8 million
Btu/hr/10,000 scfm process air flow as compared to 10.6
million Btu/hr/10,000 scfm process air fuel requirements
to operate the units, the net energy savings are  nearly
equivalent. The thermal unit must have a larger heat sink
to achieve the same energy savings.
   ENERGY RECOVERED IN
   SECONDARY EXCHANGER
   (MILLIONS OF BTUH PER
10,000 SCFH)(OR)INCINERATOR 8
 NATURAL GAS REQUIREMENT
   (MILLIONS OF BTUH
    PER 10,000 SCFM)
                                                        AMOUNT OF HEAT
                                                        TRANSFERRED IN
                                                        SECONDARY HEAT
                                                        EXCHANGER
                                         200
                                                  600   800   1000  1200   UOO
                                           INLET TEMPERATURE TO INCINERATOR (OR)
                                         EXHAUST TEMPERATURE FROM SECONDARY  (°F)
                                                            Fig. 12—Energy required/recoverable with thermal incinerators using
                                                            secondary heat recovery.
                                     SECONDARY
                                   HEAT RECOVERY.
                                      PRIMARY
                                    HEAT RECOVERY
                   Fig. 13—Thermal incinerator with primary and secondary heat recovery.
                     Primary and  secondary  heat  recovery can be  used
                   separately or together as shown in Figure 13.
                     The  energy  savings potentials of  secondary  heat
                   recovery depend on three factors:
                     • Availability of heat sinks that can effectively use the
                       energy from the exhaust of the incinerator
                     • Primary  heat  recovery  applications  and
                       requirements
                     • Economics of heat recovery options
                     The economics  of  heat recovery options will be the
                   criteria  for determining whether or  not primary heat
                   recovery should be incorporated. If a plant could use the
                   available energy from the incinerator exhaust gases more
                   effectively with a secondary heat recovery unit, the need
                   for  primary  heat  recovery would be  eliminated. The
                   energy  savings are  still achieved  because the  energy
                   supplied  to  the  incinerator  is  replacing the  energy
                   previously used for the secondary recovery applications.
                     The quantity of energy available for secondary heat
                   recovery from catalytic and thermal incinerators depends
                   on the incinerator exhaust temperature and flow  rate as
                   was illustrated in Figure 12.

                   ECONOMICS
                     The   operating  costs  of   catalytic  and  thermal
                   incinerators are greatly affected by heat recovery options
                   and the solvent concentrations in the process air streams.
                   Figure 14 illustrates approximate annual costs or profits
                   for operating a thermal incinerator. A similar figure can
                   be constructed for catalytic  units. Figure 14 is based on
                   the following assumptions:
                                                       89

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               £oo


               500


               llOO

  ANNUAL COST
(THOUSANDS OF $)  300


               200


               100
 ANNUAL PROFIT   '00
  BEFORE TAXES
(THOUSANDS OF $)  20Q


               300
. NO HEAT RECOVERY

' PRIMARY HEAT RECOVERY ty

. PRIMARY t SECONDARY ,'*
                  0    5    10   15   20   25   30   35

                    PROCESS AIR FLOW (THOUSANDS OF SCFM)

Fig. 14—Approximate annual cost/profit for thermal incineration.
    DISCOUNTED CASH
     FLOW RATE OF
   RETURN AFTER TAXES
       (PERCENT)
 PROCESS AIR FLOW

 — 30,000 SCFM

 — 15,000 SCFM
                   70
                   60
                   50
                    1(0
                                                     30
                                                                             20
                                                     10
                     300   1(00   500    600    700

                            OVEN TEMPERATURE  (°F)
                                                                                   800
Fig. 15—Economics for thermal incinerators using maximum primary and
secondary heat recovery.
    I. Profits are calculated before taxes
    2. Oven exhausts at 300° F
    3. Solvent is toluene
    4. 35 percent primary heat recovery
    5. Secondary heat recovery with waste heat boiler ex-
hausting at 450° F
    6. Incinerator temperature =  1400°  F
    7. Operating time = 6000 hrs/yr
    8. Natural gas cost = S2.00/million Btu
    9. Operating labor = $8.00/hr
   10. Supervision = $10.00/hr (50 percent of operating
cost)
   11. Maintenance = 6 percent of total investment
   12. General plant overhead = 0.58 (operating labor +
supervision + maintenance + labor salaries*)
*37 percent of maintenance costs
   13. Depreciation: 10 yr straight line
   14. Taxes and insurance: 2 percent of total investment
   15. Additional labor  requirements: operating labor
assumed to increase 1/2 hour per shift per installation
(avg. expense $2920/yr and/or $8/hr)

   For example, an oven exhausts 25,000 scfm of air at
300° Fand 15 percent of the LEL for toluene. The annual
cost of operation for a thermal incinerator without heat
recovery  is  $320,000.  If a  35 percent primary  heat
recovery unit were added, the annual cost would reduce
to  $160,000. In addition to the primary heat recovery
unit, if a  waste heat boiler were installed, the plant
operation would result in an annual profit before taxes of
$50,000 due to the net fuel savings. As compared to a
thermal incinerator without heat recovery,  a  thermal
incinerator with both primary heat recovery and a waste
heat boiler would provide an annual savings of $370,000.
   Figure  15 illustrates the economics of using thermal
incinerators with maximum primary and secondary heat
recovery.  Discounted Cash Flow (DCF) rates of return
after taxes can be determined for various oven exhaust
temperatures,   process  air   flows  and  solvent
concentrations.
   Figure 15 is based on the following assumptions:
   1. Toluene is solvent
   2. Assumed   shell   and  tube  type  primary  heat
exchanger
   3. Secondary heat recovery with waste heat boiler
   4. Incinerator temperature = 1400° F
   5. Operating time = 6000 hrs/yr
   6. Natural gas cost  = $2.00/million Btu
   7. Operating  labor,  supervision,   maintenance,
overhead, taxes and insurance, and depreciation are the
same as for Figure 14.
   For  example, an oven exhausts 15,000 scfm of air at
500° F and at  25 percent of the LEL for toluene. If a
thermal incinerator package which includes a shell and
tube heat exchanger for maximum usable primary heat
recovery and  a  secondary  waste  heat  boiler  were
installed, the DCF rate of return on the investment would
be approximately 34 percent.
   Table I provides a comparison of thermal and catalytic
incinerators using heat recovery for an oven operating
with 15,000 scfm, 15 percent of the LEL, and at 300° F
exhaust temperature.  With no heat  recovery, the fuel
requirement  for a thermal unit is about three times
greater than for  the  catalytic unit. With maximum
primary heat recovery (recuperative type), the catalytic
unit can be operated at negligible fuel flow and the
thermal unit still requires about 2.2 million Btu/hr. If a
waste heat boiler were added to each unit, the potential
net annual fuel savings are essentially the same, $68,000.
However, for this savings to be achieved for the thermal
unit, a use for 6,300 Ib/hr of steam  must be found as
compared to only 4,500 Ib/hr for a catalytic incinerator.


SUMMARY
   This paper highlighted the similarities and differences
of operating thermal and  catalytic incinerators as a
means of VOC air pollution control from metal finishing
operations. Without heat recovery options, fuel costs of
both types of incinerators could be a great penalty to the
plant.   With proper applications  of  primary,  and
                                                      90

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                      TABLE I
    THERMAL AND CATALYTIC INCINERATORS
              USING HEAT RECOVERY

  Conditions:     30ff>      15% of LEL     15,000 scfm
  Natural Gas Fuel Cost          $2 per million Btu's
  Fuel rates stated in millions of Btu's per hour

                                   Catalytic Thermal

  Incinerator fuel rate                        5.1      14.3
  No heat recovery

  Fuel rate, maximum                         0      2.2
  Primary heat recovery
  (Recuperative)

  Steam generated in waste heat               4,500    6,300
  boiler, Ib/hr

  Net annual fuel savings with heat recovery    $67,500   $68,400
secondary heat recovery and with optimization of solvent
concentrations in process air flows from the oven, energy
consumption can be minimized and sometimes result in a
net energy savings to the plant. Capital investments for
heat recovery equipment can usually be recovered in a
short time at today's energy costs.
   It is important to realize that each plant site is unique in
its operation and should have its  processes analyzed
before  implementing   an incinerator/heat recovery
package. There are many good packages offered by the
vendors;  however, each system cannot be  universally
applied to  all  applications  with  the same expected
performance and economic returns on investments. A
review of the  literature sited under "References" will
provide   many  details  and  in-dept   analyses for
implementing an incinerator add-on program.

REFERENCES
DOE Technology Applications Manual,  "The Coating
Industry:   Energy  Savings  with  Volaltile  Organic
Compound  Emission Control," TID 28706,  1979.

DOE Technical Briefing Report, "Oven Curing: Energy
Conservation and Emission Control in  Coil Coating,"
TID-28705, 1978.
                                                     91

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            "Environmental And Energy Benefits
   Achievable  By Computer  Control of Air Flow
                                 In  Bake Ovens"
                                          Matt Heuertz*
INTRODUCTION
  Methods  of reducing fuel consumption in curing
system  VOC  emission  control  incinerators  were
discussed in the previous paper, "VOC Incineration and
Heat  Recovery Systems and Economics" by  Roy  M.
Radanof, CENTEC  Corporation.  The two methods
established for reducing incinerator fuel consumption
were reducing air flows to increase solvent concentration
and installing heat recovery options to increase the inlet
air  temperature to the incinerator. These methods
similarly  apply to  curing ovens, although  for curing
ovens additional methods exist for  reducing oven fuel
consumption. Fuel usage in curing ovens is a function of
dilution air flow, operating  temperature, product and
conveyor work load, and system losses. Since the product
and conveyor work load must be a constant or increasing
energy factor, only a change in material of construction
or product and conveyor specific heats can reduce fuel
usage. These savings will be insignificant compared to the
saving potentials of the other usage functional variables.
  Oven fuel usage reduction  will result from:
  1. A reduction in oven dilution air flow.
  2. A reduction in curing oven operating temperature
requirements.
  3. Installation of secondary heat recovery.
  4. Installation of oven zone incineration.
  5. Initiation of a general maintenance program.
  This paper will discuss  the status of the Chemical
Coalers  Association Project,  which  involves  the
evaluation and demonstration of the  environmental and
energy benefits achievable by computer control of the
dilution air flows in curing ovens. Substantial energy
savings can result  from a reduction of curing oven
dilution air flows by installing a micro-computer, LEL
controller system; in addition to  the operating energy
savings in ovens and VOC emission  control equipment
and a potential  reduction in VOC emission control
investment costs, the curing operation utilizing a micro-
computer, LEL controller should be safer to  operate.
*Matt Heuertz
 Executive Director
 Chemical Coalers Association
 P.O. Box 241
 Wheaton, Illinois 60187
 CHEMICAL COATERS ASSOCIATION PROJECT
  On  September  28,  1979,  the  Chemical  Coaters
 Association signed a cooperative agreement with the
 Environment Protection Agency on a program that will
 include  an  evaluation  and  demonstration  of  the
 environmental  and  energy  benefits  achievable by
 computer control of the air flow in bake ovens.
  This multiple-phase project  will cost over $700,000
 with the bulk of the funds provided by the EPA and the
 Department of Energy, and the remainder cost-shared by
 the CCA and the company whose paint line will be used
 to demonstrate the control system.
  The  goal of the research program is to develop a
 control  system that  should  maintain solvent
 concentrations  in  existing  bake  ovens  at  levels
 approaching  50 percent of the LEL  (lower explosive
 limit). The system will be designed to provide consistent
 optimum energy utilization for variations in both paint
 formulations and the products being coated. Fuel savings
 should be experienced in  both  the  bake  ovens and
 incinerators or afterburners. The final design will comply
 with the National Fire Protection Association codes and
 standards.
  Much of the engineering and technical support efforts
 for the project will be handled by CENTEC Corporation
 of Fort Lauderdale, Florida, under a sub-contract with
 the Chemical Coaters Association.
  Charles  Darvin,  EPA  project  officer,  and John
 Rossmeissl, DOE project officer,  will provide guidance
 and  will review  the progress  of the program whose
 expected completion date is October, 1981.
  The CCA project consists of the following four work
 tasks:

 Task 1—"Potentials  for Improved Control  Tech-
 nologies"
  At least 50 user members of CCA were contacted and
 asked to provide information on their paint bake ovens.
 Data  required included such information  as: oven
capacity, types of coatings cured, fuel consumption, and
a flow diagram of their plant with air pollution control
equipment, if installed.
  The information provided by the 50 plants will be used
as input to a computer model developed by CENTEC
 which will determine  the energy and environmental
costs/benefits for curing ovens, incinerators and  heat
recovery devices by implementing a computer-controlled
oven air system. The computer model is quite flexible and
                                               92

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 will handle nearly all known plant configurations using
 continuous curing ovens.
   After compiling this background information, ten of
 these  plants will be  selected  for personal visits  by
 CENTEC engineers for further survey work.
   A conceptual computer-controlled oven air system will
 be designed and a formal risk analysis will verify that the
 system is as safe or safer than present systems operating
 at solvent levels below  25 percent of the LEL with no
 solvent monitoring/control system.
   An engineering report will be prepared that will show
 the  projected energy and environmental benefits of a
 single  plant installation and the benefits of an industry-
 wide application of the computer-controlled  oven  air
 technology.

 Task II—"Site Selection and System Design"
   The site selection for the start-up and operation of the
 prototype system will be made  by the project team as a
 result  of the findings from Task I.
   The selection of the demonstration plant site will be
 made on the basis of its similarity of operation with other
 plants to assure widespread applicability of the control
 system in the industry. Detailed cost estimates for the
 hardware and installation costs will be completed; the
 demonstration plant must cost share the purchase and
 installation   of   the  control  system.   Estimates  of
 performance, operation costs and process economics for
 other  coating  plants   will   be   defined.  The
 soft ware/hardware package for the  micro-computer
 control system will be designed. A project report will be
 prepared that will summarize the results of Tasks I and II.

Task III—"Installation and Start-up"
   Accurate documentation for the operating cost and
 performance of the oven at the demonstration site will be
 made  prior  to installation and start-up of the control
 system. The demonstration site will install the computer
 control system with technical assistance  from the project
 team.  The necessary  preparations for  start-up will  be
 concluded. Once the control system is put into operation,
 and after confirmation of the control capability, the unit
 will be lined-out to confirm the system's performance.
 Documentation of all costs will be stated for comparison
 with projections and with the oven's original operation
 prior to installation of the control system.

Task  IV—"Evaluation  of   Demonstration   and
Dissemination of Results"
  The  energy  consumption  and  environmental
efficiencies and long term reliability of the system will be
monitored. Energy savings and environmental benefits
will  be documented  by  the  project  team  with  the
assistance  of the  plant's staff. A project report will be
completed during the later stages of Task IV. The report
will describe technical and economic performance of the
system and  its  potential applicability  for the general
coating industry.  The  report  will provide  necessary
information  for  implementation by other plants. The
Chemical Coaters Association  is planning to  conduct
seminars and provide an applications manual to transfer
the results of this program to the coating industry.

POTENTIAL SAVINGS  FOR AIR FLOW REDUC-
TION
  Figures  1,  2  and 3 show the potential energy cost
savings for a given curing oven  operation.  The oven
 operating conditions initially were as follows:
   1.  Solvent concentration of 10 percent of the LEL.
   2.  Solvent removal rate of 50 GPH.
   3.  Oven exhaust temperature of 350° F.
   4.  Fuel cost of $2.50 per million Btu's.
   By installing LEL monitor/control, which permits a
 solvent concentration  of 50 percent  of the LEL, the
 dilution air flow  can be reduced 80 percent from 17,700
 scfm to 3600 scfm as shown in Figure  1.
   Figure 2 shows the  energy requirements for heating
                  SOLVENT REMOVAL RATE (GEH)
Figure 1—Oven Air Requirements for Solvent Dilution.
                     OVEN EXHAUST TEMP. Cf)
Figure 2—Energy Requirements for Oven Air Heating.
                                                     93

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 these dilution air flows. At ten percent of the LEL, the
 energy required for heating 17,700 scfm to 350° F is 6.8
 MM Btu/hr. At 50  percent  of the  LEL,  the energy
 required is  1.2 MM  Btu/hr.  The energy cost savings
 attributable to this energy reduction is $81,000 as shown
 in Figure 3. As fuel costs increase, the annual cost savings
 potential also increase for dilution air flow reduction.
                   ANNUAL OVEN FUEL COST (THOUSANDS »l

              8      8       8       §
              -I	-1,	I	U
 Figure 3—Energy Cost for Oven Air Heating.
                  CONTINUOUS CONVEYOR OVEN
                        - LOCAL LEL PROCESS
                          INDICATOR /TRANSMITTER/
                          CONTROLLER

                        - ANY PROCESS VARIABLE
                          CONTROLLED OR
                          INTERLOCKED TO
                          LEL CONTROLLER

                        - EXHAUST (EXH) OR
                          RECIRCULATION 1REC)
                          BLOWER

                        — MODULATING DAMPEB
Figure 4—Conceptual Design - Computer Controlled Oven Air Flow.
CONCEPTUAL  DESIGN—COMPUTER  CON-
TROLLED OVEN AIR FLOW
  To realize this oven fuel savings, Figure 4 shows the
conceptual design of the micro-computer controller. The
system basis for this design is a continuous, multi-zone,
conveyor oven.  The solvent concentration in  terms of
 percent of the LEL would be monitored for:
   1.  The inlet to the high temperature flash zone.
   2.  The exhaust from the high temperature flash zone.
   3.  The exhaust  from  the  higher  temperature flash
 zone.
   The reasoning for these sensor locations is that the
 majority of solvent removal will occur in the initial high
 temperature flash zone under normal system operation.
 If a system upset occurs, i.e. the product is over sprayed,
 and the solvent removal capacity of the first zone is not
 adequate to  handle this additional  solvent, then  this
 solvent will be vaporized as the product enters the next
 higher temperature zone. Since solvent concentration is
 uniform in  each zone due  to the  typically large air
 recirculation rates, monitoring the solvent concentration
 in  the  higer temperature flash  zone  exhaust will be
 representative of the entire zone solvent concentration.
 As the design  becomes  increasingly  site  specific, the
 actual number of local LEL percent analyzer/indicator/
 transmitter/controllers could  be reduced from three to
 ideally one, if the system layout will allow for multi-point
 sampling utilizing one analyzer. The LEL analyzer in this
 case should not be remotely located, since sample line run
 lengths must be minimized  to reduce the chances of
 solvent  condensation  and   pluggage due  to  resin
 particulates.
   The LEL analyzer will primarily control air exhaust
 rates by modulating  inlet   vortex,   exhaust, blower
 dampers. The LEL analyzer will be capable of automatic
 self-checking  with  alarm warning  for high  LEL  or
 analyzer malfunction. If the analyzer malfunctions, the
 auto-dampers   will   be  fully  opened to  maintain
 production. In addition to the alarm warning for high
 LEL, the system can control or interlock with any process
 variable  to  stop the coating,  stop  the  conveyor  or
 shutdown the combustion system.
   The order of magnitude installed equipment cost and
 annual operating cost for the micro-computer control
 system   are   $120,000  to  $150,000 and  $15,000,
 respectively. The discounted cash flow rate of return after
 taxes and payback on investment is shown in Figure 5 for
 various annual fuel cost savings. For an oven operating at
 350°  F and a solvent removal rate of 50 GPH with a fuel
 cost of $2.50 per million Btu's, an annual fuel cost savings
 of $81,000 would be realized  if the system dilution air
 flow rate was reduced to result in an increase in solvent
                                               •4  Z
                                                  O
              ANNUAL FUEL COST SAVINGS (THOUSANDS t)
Figure 5—Economics of Oven Computer Control.
                                                      94

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concentration from 10 percent to 50 percent of the LEL.
This savings of $81,000 annually would result in a DCF
rate of return after taxes of 44 percent and a payback on
investment of 2.4 years. For ovens operating at higher
solvent  removal  rates  and  higher  temperature,  the
potential savings for LEL micro-computer control would
be higher and,  therefore,  the DCF rate of return  and
payback would be even more attractive, since investment
cost  for  LEL  micro-computer control  is essentially
constant  for varying  system air flows, solvent removal
rates, and operating temperatures.

COMPUTER MODEL FOR OVEN/INCINERATOR
ENERGY ANALYSIS
  The Oven/Incinerator Design Model determines the
fuel   consumption  and   fuel  costs  associated  with
continuous curing  ovens and with incinerators used for
volatile organic compound (VOC) air emission control.
Fuel savings attributable to primary and secondary heat
recovery  schemes are also  computed.
  Energy utilization optimization can be determined by
increasing the solvent concentration in the oven to levels
approaching  50 percent  of the LEL. Where existing
incinerators may  limit solvent concentrations to levels
lower  than 50 percent  of the LEL, optimized  fuel
consumption also can be determined.
  The model has a built-in file  on solvent properties so
that all calculations  are based on actual  constituents
rather than average values. Solvent destruction efficiency
is factored into fuel flow computations. Spray booths or
other solvent laden air sources may be mixed with oven
air exhaust as input to an incinerator. Both catalytic and
thermal  incinerators can be  evaluated  considering
internal  and  external  combustion  air sources  and
different fuel sources. Zone oven incinerators also can be
evaluated.
  The fuel costs determined by this model may be used as
input to  CENTEC's  economics model for  determining
discounted  cash   flow  rates  of  return,  returns  on
investments, and paybacks for capital investments.
  Accurate  calculations  that normally would require
                               several  mandays of effort now can be performed  in
                               several  minutes using these models. The accuracy and
                               flexibility of this model will be demonstrated at the EPA
                               exhibit booth by providing a free analysis for your curing
                               operation.
                                 This model was utilized to develop the following case
                               studies.

                               CASE STUDY EXAMPLES
                                 Two  case studies are  presented  in Figure  6 and  7,
                               which show the fuel costs, operating costs, investment
                               costs and economics of LEL micro-computer control
                               heat recovery and VOC emission control.

                               Case I—Typical Coating Line
                                 This case involves an existing curing oven operating at
                               10 percent of the LEL, 20,000 scfm of dilution air flow,
                               350° F operating temperature, with a product/conveyor
                               work load of 42,000 pounds per hour. The annual fuel
                               costs  for these  existing oven  operating conditions,
                               assuming a  fuel cost  of $2.70  per million Btu's, are
                               determined to be $161,000. The addition of LEL micro-
                               computer control increasing the solvent concentration to
                               50 percent of the LEL reduces the annual fuel cost  to
                               $84,200 for a savings of $76,800. This was accomplished
                               by an investment of about $120,000 for the LEL control
                               system. This results in a return on  investment of 41
                               percent and payback of 2.6  years, which includes the
                               additional incremented  controller operating cost  of
                               $15,100 annually.
                                 If VOC emission  controls are required for this curing
                               operation, thermal  and/or  catalytic incinerators or
                               carbon adsorption should be considered. Since the oven
                               operating temperature is 350° F, carbon adsorption can
                               be ruled out.
                                 Thermal incineration was selected, since the coating
                               resin potentially could poison the catalyst in a catalytic
                               system.  Since  the  LEL  control  was installed, the
                               investment cost for adding thermal incineration will be
                               lower,  because  the air  flow rates were reduced. At the
                               lower air flow rates, the total installed investment cost for
                                                 FIGURE 6
                                      CASE I - TYPICAL COATING LINE

                                             Annual Syst.  Costs, $
    Configuration
                            Incremental         Total
              Incremental    Annual Fuel       Installed
Fuel Costs   Operating Costs   Savings, $    Investment Cost,
                                                                                     R01
                                         Payback,
                                           Years
    Existing oven             161,000
    (10% of LEL)

    Controlled oven            84,200
    (50% of LEL)

    Add thermal incin.         100,000
    to controlled oven

    Add 60% recirc. to          45,000
    controlled oven from
    incin.
         (or)
    Add waste heat           100,000
    boiler (5,300 Ib/hr
    stm 40 psig)
                15,100


                18,800


                 4,000




                17,700
76,800


  -0-


55,000




*72,400
120,000


126,500

 50,000



 40,300
41


-0-

86



115
2.6


-0-


1.4
    *Fuel savings in steam plant.
                                                    95

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FIGURE 7
CASE II - ACTUAL COATING LINE
Annual Syst. Costs, S


Configuration
Existing oven.
(2% of LEL)
(Controlled oven,
35% of LEL)
Add Cat. Incin. To
Exist. Oven
(To Controlled Oven)
Add Primary Recovery
To Exist. Oven & Incin.
(To Controlled Oven)
(or)
Add Oven Air Preheat
To Exist. Oven, Incin.
& Primary; 2.1 MM
Btu/Hr.
(To Controlled oven:
2.2 MM Btu/Hr.)


Fuel Costs
71,000

(48,300)

149,200

(74,800)
99,500

(58,500)

65,800



(23,100)

Incremental Total
Incremental Annual Fuel Installed ROI
Operating Costs Savings, $ Investment Cost, $ %
	 	 — —

(15,100) (22,800) (120,000) (2)

34,500 -0- 172,500 -0-


2,300 49,700 29,000 139

(16,300)

2,300 33,700 29,000 91



(1,800) (35,400) (23,000) (124)


Payback
Years
—

(8.7)

-0-


1.0



1.4



1.1

the incinerator was $126,500 with an incremental annual
operating cost of $18,800. The total annual fuel cost for
the controlled oven and incinerator was determined to be
$100,000. The plant is allowed to maintain production by
meeting VOC emission control requirements, but no
return on investment or payback is realized. To offset the
increase in fuel cost for VOC emission control, secondary
heat recovery can  be  included in the system. If  direct
recirculation of 60 percent of the  incinerator  exhaust
volume  is returned to  the controlled oven, the system
annual fuel cost will be reduced to $45,000; a savings of
$55,000 annually  or  4.1  MM  Btu's  per hour. The
investment cost for this direct recirculation system would
be $50,000 which results in a return on investment of 86
percent  and a 1.4 year payback assuming an annual
operating cost of $4,000. If direct recirculation  is  not
viable, because of product quality liability or if the plant
requires process steam,  a waste  heat boiler  can be
installed to recover the sensible heat in the incinerator
exhaust. A waste heat boiler would not reduce the fuel
cost for the curing operation, but  would save $72,400
annually in the steam plant. The return on investment is
115  percent  with  a  1.1  year payback  assuming an
investment cost of $40,300 and an annual operating cost
of $17,700. This boiler will generate 5,300 pounds per
hour of 40 psig steam.

Case II—Actual Coating Line
   This example case is an actual coating line consisting of
a curing oven and catalytic incinerator with primary heat
recovery. The existing oven is operating at 2 percent of
the LEL, 5000 scfm of dilution air flow, 340° F operating
temperature, with  a  product/conveyor  work load of
30,500 pounds per hour. The  annual fuel costs for the
oven alone is $71,100, assuming a fuel cost of $2.70 per
million Btu's. The combined annual fuel cost for the oven
and catalytic incinerator'is $149,200. If LEL  micro-
computer control was added to the oven, the oven annual
fuel cost would be $48,300; a savings of $22,800.  The
resulting return on investment and payback is 2 percent
and 8.7 years, respectively, assuming an investment cost
of $120,000 and operating cost of $15,100. For the oven
alone this would not be a wise investment, but including
the  incinerator in the analysis makes the economics
become more  favorable.  The annual fuel costs for the
controlled  oven  and catalytic  incinerator  would  be
$74,800;  a  savings  of  $74,400  annually.  Also  the
investment cost  for this  incinerator would  have been
lower than the actual $172,500, since the air load would
be greatly reduced at 35 percent of the LEL. It should be
noted that the 35 percent of the LEL is the  maximum
solvent  concentration in  this case, since  levels greater
than 35 percent  would result in an incinerator exhaust
temperature greater than  the maximum allowed for this
equipment.
  The  addition  of  primary   heat recovery  to  the
incinerator reduced the fuel costs to $99,500 for a savings
of $49,700 annually. This required a $29,000 investment
for a 139 percent return on investment and a payback of
1.0 year assuming an operating cost of $2,300. Adding
primary heat recovery to the  controlled system, the
annual fuel cost would be $58,500 for a $16,300 savings.
To further reduce fuel costs, secondary heat recovery,
oven air preheating for example, could be included in this
existing installation. The  existing system annual fuel cost
would be $65,800 for a  $33,700 savings. A  91 percent
return on this $29,000 investment and a 1.4 year payback
would  result  assuming  an annual  operating cost of
$2,300. For the  controlled  system, the annual fuel costs
would be $23,100 for a $35,400 savings. This  investment
of $23,000, assuming an annual operating cost of $1,800,
would result in a 124 percent return on investment and  a
 1.1 year payback.

SUMMARY
  The  benefits  of the CCA Project to evaluate  and
demonstrate computer control of the dilution air flow in
                                                     96

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curing ovens are numerous and include environmental,     would achieve the following major benefits:
energy, safety, and investment cost  factors. Improved        1. Reduced fuel usage in curing ovens.
control of oven  air flows will permit many plants to        2. Reduced fuel usage and investment costs for VOC
operate the curing ovens close to the maximum allowable     emission control add-on devices.
solvent concentration.  Since  the control systems are        3  Improved VOC destruction efficiency
installed at the source of the VOC emissions, the industry        4. Improved operational safety by computer control.
                                                   97

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                       Emissions  From Open  Top
                      Vapor  Degreasing Systems
                                         Charles H. Darvin*
INTRODUCTION
  Vapor degreasers are used in most metal finishing
plants to remove dirt and grease from various metal parts
with nonaqueous organic solvents.  Major users include
automotive parts  manufacturers,  metal  fabricators,
machinery manufacturers,  and some electroplaters. In
these units, the part to be cleaned is dipped in an organic
solvent vapor. Vapor condenses on the part, rinsing off
dirt, oil, and grease. The vapor is not contaminated from
previous cleaning cycles, as would be the case in a liquid
dip tank,  so  excellent  cleaning results. The  solvent
vapors, which are heavier than air, form a stable vapor
layer at the top of the degreaser. Emissions occur when
this vapor  layer is disturbed.
  Emissions from degreasers contribute a significant
amount of volatile organic compounds (VOC) to the
atmosphere each year. Solvent  degreasers alone emit
approximately  one  million  metric  tons of  solvent
annually,  about  4  percent  of total national VOC
emissions  from stationary  sources.  Most  of these
emissions are in  and around urban areas where there is
the highest concentration of metal working industries.
The U.S. Environmental Protection Agency (EPA) thus
considers it important that methods of reducing these
emissions be developed. Reduction of these emissions
would  also  serve  to   conserve  valuable  petroleum
products.  This  paper  summarizes  a comprehensive
testing  program  which   examined  the  operating
conditions that  cause VOC emissions from open top
vapor degreasers.

THE PROJECT
  In  late  1977,  EPA's  Industrial  Environmental
Research Laboratory in Cincinnati (IERL-Ci) initiated
an  extensive  research  program  to  investigate  the
characteristics of VOC emissions from open top vapor
degreasing systems.  The  initial  requirements of the
program required the identification  of knowledgeable
people and  organizations  in the field  of degreaser
technology and the construction and instrumentation of
a suitable  laboratory facility. PEDCo Environmental,
Inc., of Cincinnati conducted the program at its research
facility outside Morrow, Ohio, a location which provided
a remote area for the testing, free of any urban industrial
interferences that  could have created false data. In
'Charles H. Darvin
 Nonferrous Metal and Minerals Branch
 U.S. EPA, Cincinnati, Ohio
formulating the experimental scenarios and designing the
laboratory  facility,   PEDCo  and  IERL-Ci  relied
extensively upon the expertise of the ASTM  D-26
Committee on Degreasing, NIOSH, OSHA, and various
industrial companies which  make or utilize degreasers.
  The test program was initially scheduled to run for 12
months, but experimental results indicated the need to
expand the number of operating scenarios that should be
investigated. The program was therefore divided into two
phases.  During Phase I, the laboratory was set up,
experimental  variables were identified, and  calm air
experiments were conducted. During Phase II, the effects
of higher air velocities  across the  open top of the
degreaser were investigated.

EXPERIMENTS AND RESULTS
  The  following   operational  procedures  and
modifications  were  determined to have the  greatest
influence on emissions:
• use of covers
• ratio of cross-section of load to that of degreaser
• hoist speed
• freeboard ratio (the ratio of the freeboard height to the
  smaller interior  dimension  [length,   width,  or
  diameter])
• use of refrigerated freeboard chillers (RFC)
• physical properties of the  solvent (e.g., vapor pressure
  differences)
The experiments were conducted at a relatively constant
temperature of 70°   F (±10°) and constant humidity.
During  Phase I of the program, the draft across each
system was maintained at calm conditions (0.2 m/sec [40
ft/min]). Phase II experiments were conducted at higher
draft velocities (0.67 m/sec  [132 ft/min] and 1.2 m/sec
[240 ft/min])  across the degreaser.  Over one hundred
experiments were conducted during Phase  I of the
program, and another  fifty  during  Phase  II.  Each
experiment was run for roughly 24 hours.

Operational Procedures
  Cover - The use  of a machine cover was shown to
produce significant reductions in solvent emission rates
when operating  in  relatively  calm  air  conditions.
Machines  containing 1,1,1-trichloroethane  (TE)  and
methylene chloride (MC) were monitored in an idle state
over  a  24-hour  period.  These  experiments  were
conducted with and without covers at 0.50 freeboard
ratio; results are shown in Table 1.
  Although the absolute results of each experiment
differ, the general trend was a reduction in emissions up

-------
Table 1
Effect of Lid Position in Reducing Solvent Loss From
Idle Degreaser (50 percent freeboard ratio, RFC off)
Nonboiling
Solvent Run

TE o
MC 23
1 Run 2
Solvent loss
40
60
Boiling
Run 1 Run 2
reduction, %
5 60
33 35
to a maximum of 60 percent. This confirms the capability
of a simple work practice procedure to reduce emissions
from an idle degreaser.
   Load cross-sectional area - A second work  practice
variable that was determined to  affect  the  rate  of
emissions from  a degreaser was the ratio of the cross-
sectional area of the load to that of the  open top of the
degreaser. Special loads were fabricated to correspond to
loads  of 50 percent  of  the  system  top  area  (the
manufacturer's recommended load)  and 70 percent. It
was found that  in every operating scenario the rate of
emissions increased with  this increase  in load cross-
sectional area. As can be seen in Figure 1, increases of
emissions from  10 to 50  percent were  experienced in
systems operated at a 70 percent load cross-sectional area
compared to  those  operating with a load  area of 50
percent. This demonstrated that operation of a degreaser
within operating specifications significantly holds down
emissions.

Machine Modifications
   Hoist  speed -  Increased hoist speed was found  to
influence emission rates from an operating degreaser.
Experiments were conducted using two hoist speeds, 0.04
m/sec (8 ft/min) and 0.08 m/sec (16 ft/min). The results
shown  in  Figure  2  demonstrate   typically  greater
emissions (i.e.,  lower  solvent loss  reduction) when
operating at the  higher speed. It can also be seen that at
100 percent freeboard ratio, emissions are significantly
greater at the higher hoist speed. This indicates that hoist
speed  may significantly influence the capability of an
increase in freeboard height to reduce emissions.
   Crosscurrent air velocity - The degreasing machines
were operated at draft velocities ranging from calm air of
approximately 0.1 m/sec (20 ft/min) to greater than 1.0
Table 2
Effect of Freeboard Ratio in Reducing Solvent Loss
From Operating Degreaser at 50 Percent Load
Area, 0.04 m/s Hoist Speed, and Calm Air
Solvent
Without RFC:
TE
MC
With RFC
(-29°Cto
-40° C)
TE
MC
Freeboard ratio, %
50 75 100
Solvent loss reduction, %
2 17 50
2 22 22
8 44 44
22 44 55
 m/sec (200 ft/min) to evaluate the effects of crosscurrent
 air velocities across the open degreaser top. The results
 are  shown in  Figure  3.  In all  operating scenarios,
 increased draft velocities resulted in increased emissions
 from the machines.  At a crosscurrent velocity of 0.67
 m/sec (132 ft/min), as much as a 100 percent increase in
 emissions was observed.
   Freeboard  ratio - Experiments  into the capability of
 increased  freeboard ratio to  reduce  emissions  were
 conducted over the total range of operational conditions,
 including calm and  high draft conditions, use of covers
 and refrigerated chillers, and varying load cross-sectional
 areas. Table  2  presents  results with  and  without a
 refrigerated chiller and shows that increasing freeboard
 ratio can  significantly reduce  emission rates.  When
 freeboard ratio was increased from 0.5 to 0.75 for TE,
 there was a 20 percent reduction in emissions for TE and
 a  15 percent reduction  for MC.
50


40


30-


20
   10
   -10
   -30


   -40


   -50


   -60
                        0
                        D
             -B-
                                OTE, 50% LOAD AREA
                                DMC, 50% LOAD AREA
                                • TE, 70% LOAD AREA
                                • MC, 70% LOAD AREA
              50
                       75       TOO
                      FREEBOARD RATIO, %
                                          125
Fig. 1—Effect of load area in reducing solvent loss from operating
degreaser at hoist speed of 0.04 m/s (RFC off).
                                                              60


                                                              50


                                                            M 40

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                                                            ** 20
                                                            CO
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                                  O

                                  O
                                  OHOIST SPEED 0.04 M/S
                                  OHOIST SPEED 0.08 M/S
                                                                                  75       100
                                                                                 FREEBOARD RATIO, %
                                                                                                     125
                                                          Fig. 2—Effect of hoist speed In reducing solvent loss from operating
                                                          degreaser using TE and 50% load area (RFC off).
                                                       99

-------
CUU
**o ft
9* U
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z
£-200
o
o
ll 1
^-400
to
uo
o
1
i- -600
z
1 1 1
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_J
8-800

_innn
1 1
R
•
_


_



-

OTE, 75%
_ OMC, 75%
• TE, 125%
• MC, 125%
i i
i i i i
• • 8 °
• o _

o •
•



	
D
FREEBOARD RATIO
FREEBOARD RATIO
FREEBOARD RATIO
FREEBOARD RATIO
i i I i
              CROSSCURRENT AIR VELOCITY,  M/S

Fig. 3—Effect of crosscurrent air velocity on solvent loss from operating
degreaser at 0.04 m/s hoist speed and 50% load area (RFC off).

  Machines built  to  use MC typically employ a 0.75
freeboard ratio. When increasing the freeboard ratio
from 0.75 to 1.00 for MC, there was a further 30 percent
reduction in solvent loss. Figure 1 also  illustrates the
benefits of increased freeboard  ratio.
  Table  3 illustrates the effects of increased freeboard
ratio at various crosscurrent air velocities.
  The table also contains one  case which reverses the
general trend of a decrease  in emissions with higher
freeboard ratio.
  An increase in emissions was observed when operating
at 0.67 m/s with TE. This could not be explained by the
chemical or physical properties of the solvent, and will be
the subject of additional testing.
  Refrigerated   freeboard  chiller  -  A  refrigerated
freeboard chiller  (RFC) can  be  mounted  above a
degreaser  to  reduce  emissions  from   the   bath.
Experiments with  an  RFC  demonstrated a general
reduction in emissions from the degreasers when using
MC, as shown in Table 4.
  Table 5 shows the effects of operating at higher draft
velocities with RFC. It also shows for TE a reversal of the
trend toward reduced emissions with an RFC  that was
observed with MC.
Table 3
Effect of Freeboard Ratio in Reducing Solvent Loss
From Operating Degreaser at Various Air Velocities
and 50 Percent Load Area and 0.04 m/s Hoist Speed
(RFC Off)
Solvent
TE
MC
Air velocity,
m/s
0.1
0.67
1.12
0.1
0.67
1.12
Freeboard ratio, %
50 75 125
Solvent loss reduction, %
0 20 50
-10 -50
-120 -50
0 10 15
-160 -100
-380 -350
Table 4
Effect of Refrigerated Freeboard Chiller (RFC) In
Reducing Solvent Loss From Operating Degreaser
Using MC at Greater than/Equal to
0.67 m/s Air Velocity
Refrigerant
temperature,
° C
0
-29 to -40
Freeboard
ratio, %
75
125
75
125
Solvent loss reduction, %
RFC off RFC on
-450 -220
-250 -220
-75 -75
-120 -20
Effect of Higher
Reducing Solvent
Table 5
Crosscurrent Air Velocities In
Loss From Operating Degreaser
At 0.04 m/s Hoist Speed



Solvent
TE



MC





Air velocity,
m/s
0.67

1.2

0.67

1.2



Freeboard
ratio, %
75
125
75
125
75
125
75
125
Solvent /oss
reduction, %

RFC off
-100
-150
-110
-50
-250
-175
-360
-320

RFC on
-200
-200
-180
-180
-150
-150
-260
-230
DISCUSSION OF RESULTS
  A number of significant conclusions can be developed
about  the  nature  and  control  of emissions  from
degreasers as a result of this evaluation program. Use of
simple operating  procedures  such as low hoist speeds,
closing of the system  lid when  in idle  condition, and
shielding the  system  from high  draft  velocities can
significantly reduce emissions. These changes, however,
require a conscious and continuous effort on the part of
the operator. Passive control options such as increased
freeboard and  refrigerated chillers were shown to be just
as  effective  and   require   only  installation  and
maintenance for continuous control.
  The  data also  show the capability of each  control
option when used separately or in tandem. It was shown
that secondary chillers achieve greatest control benefit at
lower freeboard ratio levels, 0.5 for MC and 0.75 for TE.
As  freeboard ratio increases, its capability approaches
that of the secondary chiller. This was found to be true at
both lower and higher crosscurrent air velocities for MC.
However, this  trend was found to be reversed with TE,
and no viable explanation based on chemical or physical
properties of the solvent has been found. An extension of
the program  to  include  approximately 30 or  more
experiments has therefore been scheduled. During those
experiments, a more detailed evaluation will be made of
secondary   operating  variables  such as  ambient
conditions and aerodynamic effects.
  The conclusions that have been and will continue to be
developed after completion of the testing  can have a
major impact upon future degreaser design and operating
                                                    100

-------
practice.  Both  plant  layout   and  production  line
scheduling can be  impacted.  To  reduce  emissions, a
degreaser should be placed in a location shielded from
high drafts, either by installation of baffles or by proper
placement in the plant. Hoist speed should be maintained
at relatively low velocities (which could require control of
the speed of the production line).  The maintenance of
loads at  low  cross-sectional  area  could  also  limit
production rates. Finally,  the  use of add-on control
options  could influence equipment  location in the plant.
These operating  practices and design modifications,
however, represent in most cases relatively inexpensive
options and would  produce  only minor changes  in
normal plant operations.
  A summary report  of the Phase I  efforts  is  in
preparation.  This report will include the results  of
experiments  conducted  primarily  under calm  air
conditions. It will be available for distribution in July
1980. The Phase II report is awaiting completion of the
remaining 30 experiments analyzing the unusual  TE
results. It will be ready for distribution in September
1980.
                                                    101

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                        V.O.C. Control  Efforts  By
              A  Heavy Duty Truck  Manufacturer
                                          Edward W. Kline*
  Can you visualize a 9.9 mile traffic jam? That's the
distance the  line of tank trucks  would stretch if one
thousand and forty-three of them were parked bumper to
bumper. It  would take 1043 tank  truck deliveries to
supply 7.3 million gallons of #2 fuel oil.
  I mention these figures because 7.3 million gallons is
the amount of #2 fuel oil it would take if we were to incin-
erate  Volatile  Organic Compound  emissions  from
painting  operations  at  Mack Trucks  Allentown
Assembly Plant.
  To get a better feel for the magnitude of these figures,
consider the following:

    If you round off the cost of a gallon of #2 heating
   oil at $1.00 per gallon, you have an annual oil bill of
   7.3  million dollars. Average that over the 20,000
   trucks we built in Allentown last year and it would
   cost an additional $365 to paint a truck.
    If you use  1500 gallons of #2  oil to heat your
   home each year, 7.3 million  gallons would  be
   enough oil to heat a city of 4866 homes. Now even if
   this quantity of oil were available, which it is not,
   one has to ask—Is such conspicious consumption
   advisable given our present world situation?

   I am  sure most  of us recognize the  importance of
V.O.C. control. The EPA has presented convincing facts,
figures, and statistics to serve as incentives.
   However, it is my firm belief that as Environmentalists,
Scientists,   Engineers,  Enforcement  Agencies,  and
Industrial   Managers,  it   is  our  responsibility  to
accomplish this  control in an effective and economical
manner.
   As I see it there is no one universal solution to the
problem of V.O.C. control. That is of course unless there
is  a revolutionary breakthrough in coating technology.
   Each process  should be examined on an  individual
basis if you want to determine the most favorable control
technology. Let's review the circumstances affecting our
decisions at Mack Allentown.

PRODUCT REQUIREMENTS
   Mack Trucks are separately engineered  to meet
customer  specifications and individual needs. We are
custom truck builders.
   The trucks we build cost in  the neighborhood of
$50,000. Unlike most automobiles,  our entire truck is
painted—chassis and all. The projected life expectancy is
5-10 years. However, some are in use more than 20 years
'Edward W  Kline, Section Supervisor
 Environmental Control
 Mack Trucks, Inc., Allentown, PA
and still  going strong.  It is  not  uncommon to hear
customers talk about breaking the million mile mark with
their Mack.
  Mack Trucks are in use around the world and are
exposed to weather conditions which range from desert
heat to arctic cold. Naturally, our customers also expect
the finish to meet certain requirements such as: Long
Term  Weather   Durability;  Color  Choice  and
Appearance  Hi-Luster;  Color and  Gloss  Retention;
Ability  to  Withstand  Extreme  Environmental
Conditions such as Heat, Cold, Abrasion,  Corrosion,
and  contact  with Chemicals  &  Oxidation;  Chip
Resistance.
  As you can see, living up to these tough expectations
requires a paint finish highly durable in nature. We use
Thermo-set acrylic enamels to meet these requirements.

TYPES OF ENGINEERING  CONTROLS
  A. Improved  surface coating  transfer  efficiency.
Looking  at both ends of  the  spectrum,  we  find
conventional  air  atomization spray painting  has  a
transfer efficiency of 30 - 60%.
     Airless electrostatic spray  painting has a transfer
efficiency of 80 -  90%.
  B. Materials Substitution—By  weight an  average
gallon of solvent base paint contains between 4.5-6 Ibs.
of V.O.C. An average gallon of  water borne coating
contains between 2 - 3.5 Ibs. of V.O.C.
  C. Physical  Controls—Carbon  Absorption  systems
are being utilized, This type of V.O.C. control ranges in
efficiency from 40 - 90%. Generally carbon absorption is
being used when quantities of air are reasonable.
     Catalytic and direct incineration systems have been
rated at 90 - 100% V.O.C. control efficiency.
     Refrigeration systems used for low volumes of air
range from 40 - 80% V.O.C. control efficiency.

SUCCESSFUL   APPLICATIONS  AT  MACK
TRUCKS ALLENTOWN ASSEMBLY PLANT

Chassis Spray Painting
  Conventional spray painting  has been the industry
standard for years. We replaced conventional chassis air
atomization  spray painting  with airless electrostatic
techniques. This reduced V.O.C. emissions by 21 tons per
year.
Small Parts Painting
  Our  small parts painting operations includes a wide
variety of parts that range in size from doors to brackets.
A total of 72,000 square  feet  of surface coating  is
completed in an 8 hour shift.
  In  this  operation  a  combination   of materials
substitution, improved transfer efficiency, and catalytic
                                                 102

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incineration are used to eliminate 40 tons of V.O.C.
emissions annually.

Substitution  of  Materials  and  Improved  Transfer
Efficiencies
   Many parts which had been painted by conventional
air spray  methods now receive  electrophoretic  paint
coatings.
   The electrophoretic coating takes place in  a 13,000
gallon dip tank. It is  a water  borne coating which
contains 1.9 Ibs. of V.O.C. per gallon of coating. Plating
voltage of the system ranges from 250 - 350 volts  D.C.
The current density is 5 amps/sq. ft.
   Air  and airless electrostatic painting techniques are
being  evaluated  and   perfected  for  color  spraying
operations.

Emission Control Technology
   Exhaust air from 3  paint  drying ovens is funneled
through a  catalytic incinerator. In an 8 hour  shift 4.8
million cubic ft of  air  passes through the incinerator.
Oven temperatures are maintained at 250° F (121° C) for
paint drying. The incinerator is a Schweitzer Sicor unit. It
contains 9 cubic  feet  of  DuPont  Torvex Platinum
Catalyst. The Catalyst allows incineration to take place
at temperatures between 700 & 900° F. Fifty gallons of #2
heating oil are consumed each  hour to operate the
incinerator.
  John Kroehling of DuPont  worked closely with us on
this project. John expects the Catalyst to last 3-5 years.
   The 9 cubic feet of Platinum Catalyst is designed in a
 honeycomb fashion.  The  honeycomb effect produces
 300,000 square feet of catalytic contact surface  area.

 Heat Recovery
   Indirect  heat  recovery is used to reclaim 4  million
 BTU's of incinerator  heat  each hour. The recovered
 energy is used to heat the Electropheretic dip oven to a
 temperature of 350°  F.
   The  recovered  heat  and   lower  temperature
 requirements of  the catalytic incinerator produce an
 annual savings of 53,000 gallons  of #2 home heating oil.
 That's enough oil to heat 35 - 40 homes in the Lehigh
 Valley each year.

 CONCLUSION
   As I see it, there is no universal solution to the control
 of V.O.C.  emissions unless a breakthrough in  coating
 technology occurs. A combination of improved transfer
 efficiency of coatings and materials substitution, when
 practical, appears to be the most favorable approach to
 V.O.C. control.
   Incineration with heat recovery has application when
 an energy balance can be obtained. The use of carbon
 absorption or refrigeration principles have application
 when air volumes are  low  enough, or when there is a
desire to recover lost product.
  The most effective results will be obtained by carefully
examining the merits of each process in conjunction with
the control applications which are available.
                                                   103

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          Centralized Treatment and Disposal  of
                            Special Wastes in  the
                    Federal  Republic of Germany
                                             N. Roesler*
INTRODUCTION
  In "Environmental Protection" and, generally, in the
"Improvement of Quality of Life", special wastes in the
form of gases, liquids, and  solids,  and  even noise are
becoming more and more important in comparison with
normal municipal  sewage and garbage.  Although the
legal task of the public Wastewater Treatment plants is
the  acceptance and  treatment of normal municipal
wastewater, we found that we were struggling to treat
unusual waste components, which, despite federal laws
and municipal regulations, entered  into the sewers and
complicated  the treatment  of wastewater. Different
Institutions,  therefore,  have become concerned  with
various branches of industry and their liquid wastes.
Since about 1960, in the Federal Republic of Germany,
intensive efforts have been made which have resulted in
various more or less, centralized treatment plants with
facilities for treating the wastes coming from different
industries

ORGANIZATION
  An example of facilities based on more private and
voluntary activities is represented by  the Ruhrverband
which comprises  a part  of the land of Northrhine-
Westfalia.
  The central Decontaminating Plant, Iserlohn (ZEA-
Iserlohn),  the  first  plant  in West Germany,  was
completed in 1964. This  plant treats metal  finishing
wastes from an area of 380 km2, comprised of the town of
Iserlohn and  eight municipalities, forming the district of
Iserlohn. In this area, there are about 200 installations, in
most cases medium-sized industrial enterprises which are
running approximately  1000 baths  for galvanizing,
anodizing and non-ferrous metal pickling, with a total
volume of roughly  1000 m3.  (See Figure 1)
  After  obtaining  the agreement of  all the associates
concerned, the Corporation for the  Advancement of
Industry Ltd., Iserlohn, took over the responsibility for
metal finishing waste treatment in this area, and charged
the  Ruhverband  for  planning,  constructing  and
operating the plant, in accordance with section 3 of the
Ruhr Pollution Act (law of the regional government of
Northrhine-Westfalia).
  The ZEA-Iserlohn plant is divided into three sections
(Figure 2). The first section comprises the collection
*N. Roesler
 Department of Sewage Treatment
 Ruhrverband D-43, Essen, Germany
EjD  12000
El  12000
H]  10000
S  60000
[B  26000
             3000
             2000
             3000
             2000
Fig. 1— Central Plants for the Treatment of Hydroxide Sludges in the
Catchment of the River Ruhr.
           Receiving of wastes in tank cars.
           containers, large.small.and mini loads
      Acid storage basin
    Hydrochloric acid pickle.
    sulphuric acid pickle,
    chromic acid
                       Alkaline waste storage basin
                        Cyanide-containing wastes,
                        degreasmg and drawing
                        baths, liquors
                            Cyanoxidation
                  Neutralization
                   Iron oxidation
                   Sedimentation
                  Sludge storage
                I  Sludge dewatenng

                '
                  Dumping of sludge
Fig. 2—Schematic diagram of a central plant for the removal of toxic
substances from electroplating plants and pickling plants.

tanks, and the cyanide oxidation and chromate reduction
facilities.  Section  two  is  the  neutralization  and
desludging facility for wastes coming from section one, as
well as for acid and alkaline solutions from aluminum-
anodizing plants, and iron and non-iron pickling plants.
The  third  section  comprises the  following steps:
thickening, dewatering and disposal of hydroxide sludges
coming  from section  two.  It also handles sludges
                                                104

-------
delivered from companies which have pretreated their
wastes to the extent they have found economical to do in-
house. The ZEA-Iserlohn can, therefore,  handle toxic
concentrations,  thin  and  thickened  sludges,   and
dewatered sludges requiring disposal. This allows each
associate to choose the  grade of pretreatment which is
most economical for him, and consequently, the cheapest
way to dispose of his wastes.
  In  the  case of  the  second  plant,  the  ZSEA-
Heiligenhaus,  the  responsible   authority  is  the
Dusseldorf-Mettmann (Figure  3).  The various
installations in this area  preferred to handle the first and
second  sections (as described above)  of wastewater
treatment  within  their   own  plants.  Hence  the
Ruhverband  planned   and  constructed   a storage,
dewatering and  dumping  facility  for sludges from
Heiligenhaus and has been operating since  1968. Unlike
the ZEA-Iserlohn, membership is compulsory for all the
installations unless  one can  prove  that  wastewater
discharges from his own plant  comply with the law.
             -15KM
 • Central plant for
   dewatering and disposal
                                    Number of factories
                                    producing hydroxide
                                    sludges
Fig. 3—District Dusseldorf-Mettmann concentrations of factories in the
district.
  A third  plant has been constructed  by the town of
Ludenscheid and a private garbage collector is running it
for another 100 installations.
                      Two  further plants run by  private contractors are
                    handling emulsions from rolling mills and another one is
                    collecting and recovering spent hydrochloric acid.
                      These'plants have become the central collection and
                    treatment facilities for all special wastes coming from the
                    metal finishing industry in this area.

                    Managing
                      The technical supervision of the two plants operated by
                    the  Ruhrverband is  handled by  two engineers in
                    cooperation  with two nearby  wastewater treatment
                    plants. The engineer involved in each case is able to add
                    or withdraw workers according to  need. Normally, two
                    workers are required to operate the  plant in Iserlohn and
                    one in Heiligenhaus.
                      The financial management is done by a  group of
                    elected men who represent the industry (associates), the
                    responsible  corporation,  the  local  authorities,  the
                    Ruhrverband, and the  Chamber of Commerce. Each
                    year, the financial statements and plans for the following
                    year are presented by  the managing engineer to the
                    representatives for approval.

                    Financial Aspects
                      For financial purposes, the metal finishing  industry
                    (galvanizing,   anodizing and  pickling  factories)  in
                    Iserlohn has been separated into three groups according
                    to the volume of their baths, the amount of chemicals
                    bought,  the  quantity  of process   water  needed,  the
                    quantity of sludge produced, and so on. Also taken into
                    account is the degree of participation  or the amount of
                    pretreatment carried out by the companies themselves. A
                    small plant wanting to participate in all steps of central
                    treatment may pay, for instance, 5000-DM, while a large
                    company  which   sends  only  dewatered  sludge  for
                    dumping may pay 20,000-DM for the disposal.
                      In addition, the Ruhverband has granted a loan of
                    150,000-DM, the town of Iserlohn a lost subsidy of
                    50,000-DM and the regional government another  lost
                    subsidy  of about 200,000-DM, towards the costs of the
                    Central  Plant.  The construction costs for the Central
                    Treatment Plant for Iserlohn, including a second filter
                                                  TABLE 1
                          CHARGES FOR THE USE OF TWO CENTRALIZED PLANTS
                   FOR REMOVAL OF INDUSTRIAL TOXICANTS, IN DM PER CUBIC METER
   Members participating, non-members
   = not participating in the
   construction of the installation

   Acid and Cr acid semi-concentrate
   Acid and Cr acid concentrate
   Semi-concentrate containing CN
   Concentrate containing CN
   Eluate from ion exchangers
   Acid pickling waste waters
   Spend pickling fluid containing
    sulphuric acid
   Pickling fluid containing = 5 g Cu/l
   Pickling fluid containing = 15g Cu/l
   Dilute sludge ~ 3% DS
   Dewatered sludge ~ 30% DS
                                           Central detoxification plant Iserlohn *
                                      1. Construction phase   2. Construction phase
Non-members

  150. - DM
  200 - DM
  170-DM
  247 - DM
   90- DM
members
                Non-members
                    74.50 DM
                    29.50 DM
                    20.  DM
                    6.55 DM
                    12.50 DM
                  87.60 DM

                 113.80 DM
                  52.60 DM
                  20.   DM
                   9.   DM
                  19.50 DM
                                                        ZSEA"
                                                     Heiligenhous
members
17.40 DM
16.   DM
    excluding shipping costs and value added tax
   'including shipping costs and value added tax
                                                    105

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                                                    TABLE 2
                            RUNNING COSTS FOR CENTRAL NEUTRALIZATION, 1974
    Receipts

    Neutralization of liquids from

    11 members

    about 50 non-members


    Receipts from liquids sold


    Interest for reserves
   DM




 28,900

300,500


   600


 15,800

345,800
Expenditures                             DM

Wages                                  23,500
Chemicals                              32,100
Energy                                  1,600
Costs for sludge handling                  80,800
Maintenance                            66,600
Reserves for maintenance                  40,000
Insurance for risks                        20,000
Technical and administrative
 supervision                             47,400
Reserves for unforeseen                   32,200
Transport costs for concentrates sold         1,600

                                      345,800


TABLE 3
RUNNING COSTS FOR SLUDGE HANDLING
Receipts
19 members
dewatered sludge
thin sludge

non-members
dewatered sludge
thin sludge
costs for special treatment
Hydroxide sludges from
central plant (galvanizing industry)
Hydroxide sludges from
central plant (pickling industry)
Interest for reserves


DM
26,600
11,200

AND DISPOSAL
Expenditures
Wages
Chemicals
Energy


Transport and Disposal
Reserves for recultivation
7,800
50,300
6,500

31,200

Maintenance


Reserves for maintenance

Insurance for

risks


DM
28,800
3,600
2,000
18,000
15,700

69,600
30,000

3,200
Technical and administrative
80,800
21,500

235,900
supervision

Interest for loan
Reserves and

unforeseen

21,400
5,200
28,400
235,900


SUMMARY

ON STATUS AND
Status 31/12/73
Central Neutralization
Reserves for maintenance
Reserves for unforeseen
Central Sludge Handling
Reserves for recultivation
Reserves for maintenance
Reserves for repayment of loan
Reserves for unforeseen

1967-1973 DM
85,000
95,900

40,700
45,000
105.000
47,700

TABLE 4
DEVELOPMENT OF
Withdrawal
1974
- 10,000
- 15,000

- 6,700
- 10,000
—
-11,200


SPECIAL RESERVES
Increase
1974
+ 40,000
+ 32,000

+ 15,700
+ 30,000
	
+ 28,400




1967-1974
115,000
112,900

49,700
65,000
105,000
64,900
512,500
press and a second dump for about 50,000 m,3 totaled 2
million  DM. The second  filter press and the second
sludge depository were paid for from savings  on the
operating costs.
  Similar financing  has been arranged for the ZSEA-
Heiligenhaus.  In a third case,  construction costs were
paid for through a loan, so that the capital cost, (interest
and  repayment) must  be  calculated as  part  of the
operating costs.
                  The operating costs for the ZE A-Iserlohn are shown in
                Tables 1,2,3 and 4. They are lower than for any other
                central treatment plant in Western Germany; most costs
                have not risen for 16 years. An example of the annual
                calculation of profit and loss can be seen in Table 2, for
                neutralization, and in Table 3, for sludge handling. The
                status of special reserves is shown in Table 4. In the past/
                all necessary expansion programs have been paid for out
                of the special reserves.
                                                     106

-------
  If the capacity allows, waste is also accepted from the
so-called non-members.  They must, however,  pay a
higher price than members for the service.

Preparation, Collection and Transportation
Of the Wastes
  A minimal pretreatment must be carried out  by the
companies themselves. First, the quantity of rinsewater
must  be reduced  through improved rinsing techniques.
This can be achieved either by using a still-rinse after the
bath and two or three counter current rinses,  or by using a
more  technically  advanced method: one still-rinse and
one  flow-rinse in  combination with  ion-exchangers
(Figures 4 and 5). The first method results in so-called
semi-concentrates and a lesser quantity of rinsewater.
These must  either be treated in the plant, or stored in a
tank  until a quantity has been collected which  can be
economically transported to the central treatment plant.
  In the second method of still-rinse, flow-rirtse and ion-
exchangers, a very low quantity of freshwater is needed to
make up the  losses in the rinsing cycle, but different
storage tanks must be provided for the acid  and alkaline
solutions.
  For collecting, storing and transporting the liquors, we
offer  containers  of different size  (60; 200; 800 liters)
without any additional payment. If the quantities are
greater, it may be  more economical to build some storage
tanks in the plant  itself and transport by 5-, 10-, or 20-m3
trucks. This  is being done, for instance, when thin sludges
from in-plant treatment facilities have to be transported
once or twice a month to the central treatment plant.
  In  the  case of  the central  dewatermg facility in
Heiligenhaus, transport of the wastes from the industrial
plants to the facility is handled by one transport company
which charges the same price,  regardless of the distance
involved.   This   cooperative  principle   eliminated
disagreement  about the  location  of the  facility and
possible economic  disadvantages  which  may  have
occurred in  transporting the wastes.

Operation and Maintenance -
Recovery of Liquids
  This paper is not intended to give the chemistry of the
oxidation of cyanides, or of the reduction of chromates,
or of neutralization. The following section  details some
of the experiences we  have had  with out central plants
and the solutions we found to some problems.
  We found that one of the most important items was
storage capacity. Adequate storage capacity saves on
time  and expenses  for  chemicals  and, therefore, on
operating costs. For instance, when the central plant for
Iserlohn was started, we found that a large quantity of
NaHSO4 was required for the reduction of chromates.
We began to collect and store iron-chloride and iron-
sulphate solutions  for use instead of  NaHSCX  This
eliminated the need to buy expensive chemicals which, in
any case, increased the salt concentration in the effluent.
We also store the alkaline solutions we collect, for use in
neutralization, as well as in the oxidation of cyanides, as a
substitute for sodium hydroxide. Alkaline solutions are
also used to dilute concentrates to  1 g CN/1. Certain
concentrates, in most cases small quantities, can also be
collected,  equalized in  quality and  be prepared for
recycling if storage space is available. We are collecting
some hundred m /year of copper and nickel containing
solutions, which are transported in 20 m3 containers to a ,
                                                          Chemicals
                                                                                               Fresh-Water
I 	 1 §
1 i
Bath

i s
s
0
]u


1
U
s
0
1 1
Effluent to Effluent to Sewerage
Storage Tank or Jn- Plant Facilities
or Jon- Exchanger
Fig. 4—3-step-counter-current rinse with flow-rinse.
 v
 D
 Co
 Cn
Number of Rinses
Flesh Water
Ladling Rote
Concentration in Both
Concentration in the Last Rinse
                                          100 V/O
                             V/D -Fresh Water/Ladling Ratio
                             CofCn" Factor of Dilution
Fig. 5—Water consumption of counter-current rinse.

Sediment Iml/l]
pH - value
Chromium [mg/II
Copper Img/H
Nickel [mg/ll
Zinc (mg/ll
Cadmium [cng/l)
Iron lmg/1)
Tin |mg/l]
CN decomposable Img/l]
by chlorine
Free chlorine 1 mg/ll
Standards
when dis-
charged to
0.3
6.5-9.0
2.0
1.0
3.0
3.0
3.0
2.0
-
0.1
-
Standard
A115
•I
6.5-9.5
4.0
3.0
5.0
5.0
-
•I
-
1
-
Berlin
0.5
6.5-6.0
1.0
0.1
1.0
3.0
1.0
-
5.0
0.1
—
Fronk-
furt
1
6.0-9.0
2.0
2.0
2.0
2.0
2.0
20.0
-
frei 0.3
komplex
1.0
1.0
Koln
-
6.0-9.0
2.0
2.0
3.0
2.0
2.5
5.0
2.0
0.5
-
Zurich
—
6.5-9.0
2*
1.0
2.0
2.0
1.0
-
2.0
0.5
0.5-3.0
 *) Limits in dependence of the receiving treatment plant

Fig. 6—Standard values for the toxicant content of waste waters when
discharged Into a sewerage system.

central non-ferrous-metal recovery plant operating on a
private basis. Some of the industrial installations are now
collecting these solutions themselves, rather than having
the central treatment plant do  so.
  In future, some special solutions will be collected and
stored for use  in the Ruhrverband's treatment plants.
Instead of buying expensive chemicals for  phosphate
                                                     107

-------
precipitation,  we  are now  using  the  iron-chloride
concentrates from iron pickling plants,  after equalizing
the concentration and destroying the free hydrochloric
acid by adding iron  oxide  from another central plant
which operates on a private basis. This plant is recovering
about 2 m3/h of hydrochloric acid by  combusting the
spent concentrates. (Figs.  1, 6) This procedure agrees
with the "Waste Recovery Program  of the  Federal
Government  of West Germany".  Adequate  storage
capacity also makes  continuous and stable treatment
possible. We are able to accept all quantities of waste
(from a beaker to a 20 m3 container), in all qualities (from
concentrates, semi-concentrates, thin  and  dewatered
sludges) at any time.
  The pumps are another important consideration in the
treatment plant. One should not try to find a  pump
material which will withstand all challenges.  The pumps
which can be repaired easily by replacing rotating parts
and gaskets after having removed a few screws, and not
after dismantling the whole plant, should be used. This
also applies to the mixers.
  The chemical treatment process must be automated to
reduce the number of operators required and to obtain
consistent results.  A  complete central plant  which
includes chemical treatment and disposal facility really
requires only one man to operate it. However, a single
man is not permitted to work alone in such a plant, so two
men are required for each shift and back-ups  are
necessary in case of  illness, and during vacations. Our
back-up operators are supplied from a nearby sewage
treatment plant.
  Protection from  corrosion  is  another   important
consideration. Naturally,  all  storage  tanks  must  be
carefully sealed.  Even neutralized sludges have a strong
corrosive effect, because of their high salt concentrations.
Hence the filter press plates should be coated by heating
the cast iron plate and dipping it in a  fluidized bed of
special  polymers.  Plates  manufactured from  special
plastic could also be used.  The effluent from a central
plant has salt concentrations of up to  5 g/1 SO4, 1 g/1
NO3 , and 5 g/1, Cl.  NO2" and 0.2 g/1 NH4 may also be
present. This effluent is, therefore, discharged to the inlet
of the wastewater treatment plant, after passing through
a  final settling tank of  long  detention  time. This
treatment is necessary not  only to oxidize  ammonium
and to reduce nitrates, but also to dilute  the salts that are
toxic to fish.

Disposal, Supervision of the Disposal Site,
And Recovery of Special Sludges
   The dewatered sludges from the central plant, as well
as those from company-owned facilities are dumped at a
disposal site. The disposal site usually includes lagoons
for anaerobically digested municipal sludges and areas
for dewatered hydroxide sludges. The bottom of the site
is sealed with clay. Any percolating or surface water is
withdrawn and returned to the central  treatment plant.
There is  usually  no surface  water   at all,  and the
percolating  water contains only  very small traces of
metals, always below the standards required in Germany
for waste disposal. (See Figures 6 and  7.)
   The disposal sites  should be surrounded by trees, or at
least by bush, since  wind erosion can cause problems.
   Special sludges containing copper, nickel and zinc are
being stored  separate from the iron  and chromium
containing sludges (Figure 8). If the metal market allows,

Sediment [mg/l]
pH -value [mg/l]
Copper [mg/l]
Zinc [mg/l]
Nickel [mg/l]
Chromium [mg/l]
Iron [mg/l]
Cyanide [mg/l]
Dump
Iserlohn
0.1
7.6
0,1
0,1
1.3
0,1
0.7
0.1
Dump
Heiligenhaus
0.1
8.0
0,2
1.3
0,4
0,1
0.9
0,1
Fig. 7—Contamination ot seepage Irom two centralized industrial sludge
dumps.
sludge
sample
1
2
Cu
3.35
11,4
Zn
2.85
4.7
Fe
0,09
0,02
Cl
0.17
0.62
S
15.4
11.9
CaO
29,5
22,5
AI203
0,15
0.15
H20
50
50
Fig. 8—Analysis of Sludges for Recycling

these sludges are given away for free, in order to save on
disposal site space. Liquid and solid material wastes from
the electroplating,  and  brass  and  copper pickling
industries are  recycled to  save on  operating  costs,
capacity and volume, not to make a profit.
  The   Ruhrverband   collects   about  10,000  t/year
hydrochloric acid (containing 130 g Fe/1  and 5  g  free
HC1/1), and 20,000 t/year of FeSO4'7H2O  from iron
pickling wastes. This represents a  real economic factor as
a raw material for the chemical industry. However, the
sale of these products covers only the transportation
costs, although we also save by  not  having to pay for
neutralization, desludging, dewatering and dumping.

Other Wastes that can be Accepted
   CN~ and NO2  salts from hardening  furnaces are
collected in containers at the industrial plants and sent to
a central collection site, (Fig. 1, A) from which they are
taken to an old salt-mine and disposed underground. All
solid toxic materials are also handled in this way.
   Water from cooling baths is occasionally brought to
the central treatment plant at Iserlohn. Chemicals from
laboratories and from the army (sodium hydroxide,
calcium hypochlorite, etc.) are also accepted at the plant.
As long as the capacity  of our central  plant  is  not
exhausted, we  accept these materials  from all over
Northrhine-Westfalia,  and even from  other parts of
Germany.
   A bulletin published through the "German Recovery
Program" lists various installations which accept special
wastes, liquids  or  solids,  toxic or inert, organic or
inorganic wastes.

Acceptance of Centralized Treatment
Concepts in Other Countries
   Several projects for centralized treatment plants are
being  developed outside of Germany, for example,  in
Norway, Denmark  and Switzerland. However, none  of
 these except Denmark has yet passed the planning stages.
 Many central facilities for special wastes  from various
 industries  are  operating successfully in Germany. We
 have found such facilities to be  the best solution to the
                                                     108

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problem of pollution control in a country that has limited
resources of land,  air and water, and which is densely
populated  like ours.

Economics of In-Plant Treatment
Versus Shipping to a Central Plant
  The decision as  to whether it is  more economical to
treat wastes in an in-house facility or to transport them to
a  central  facility  requires  careful investigation.  The
present situation, and possibilities of future development
must  be examined  in each case, and the following items
should  be  taken into account:
  1) Cost of in-plant changes.
  2) Cost of pretreatment up to desludging (3% solids).
  3) Cost of further thickening and dewatering.
  4) Cost of transporting and disposing of the filter cake.
  If points 1) and 2) are considered in conjunction  with
the quantity of rinse water required, it is found that,
below  a certain volume of  rinse water, it  is more
economical to use a central facility.  Beyond this volume,
it is cheaper to use an in-house facility. Naturally there is
also a  zone  of uncertainty  where  it is  possible to
determine  which is most economical.
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         1    3  5  10    3  5  10!   3  5  103  3 5  10'
               	Rinsing Water [mVd]	>
Fig. 9—Specific annual costs of water treatment with In-plant and central
stations as a function of rinsing-water quantity (without dewatering and
disposal sludges)


   Thin sludges and filter cakes must be considered in the
same manner, in order to decide whether to handle them
directly or ship them to a central treatment plant.

   Figures 9, 10, 11 and 12 have been prepared using our
data for interest and  repayment, operating time, annual
depreciation,  transportation  distances,  benefits  for
government, and savings on the cost of fresh water and
sewerage  for  the   municipal  treatment  plant  and
associations  such  as  Ruhr  River  Association and  the
Ruhr Reservoir Association.
   Now  let me  show you the  example.  A galvanizing
plant, which required  100  m3 of fresh water per day
redesigned its  entire processing line and improved the
waste treatment sections for  each processing unit (Figure
13).
   The first step was to improve metal recovery. This
means that copper, nickel, zinc and chromium containing
liquors must remain either on the surface of the material
to be finished or in the bath. How can this be done? If you
pull the material out of the bath and take it directly to the
    Quantity ol sludjt (m>«)
    containing 3V* dry matter
                                              sludf*
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30
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 Enrtched to form
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                                                                                    Rinsing water production [m'/dj


                                                                                               (Ditule sludge to central
                                                                                               delo,,I,ca.,on plant
                                                                                               Dewalered sludge to
                                                                                               central dump
                                                                                               Oe-otered sludge to
                                                                                               eslablishmenl-owned damp
                                                            fig. 10—Organization of toxicant removal subject.
A

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ant
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htckened Sludge
once for Risks
and Disposal
e
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                                                                            Thickened Sludge [mj/d]
                                                            Fig. 11— Specific costs of in-plant and central sludge dewatering devices.
                                                              T
     680

     UO

     ,400
                                                              .i 360

                                                              S  320
                                                              £
                                                              =  280

                                                              .2

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                                                              o
     160-

     120

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                                                                                                              4.5
                                                                     012345678
                                                                           	Factor of  Dipping [n] —
                                                            Fig.  12—Bath-losses •* • (unMton of the quality ct i
                                                            from the bath.
                                            9  10
                                                       109

-------
rinse you remove, let us say, a maximum of 100% of the
liquor. If you allow the piece to drip into the bath for 15
seconds, this  value drops to about  60% and for 60
seconds, to 30%. By adding an electromagnetic vibrator
with variable frequency and amplitude so that the best
combination can be determined, you can  minimize the
bath losses to 10% by vibrating the rack while removing it
from the bath. Ladling parts should be suspended so that
the concentrates can flow out of the hollows. The rest can
be blown out with air. Every percentage you save is your
money, represented by the need for less metals or metal
salts, less water for rinsing, and  less wastewater to be
handled. You  cannot  protect your  environment by
wasting water and materials and you must concentrate
the inevitable losses in as small a quantity of water as
possible. Dilution will not keep your water clean.
  The next step in good housekeeping is a good rinsing
process with counter current water flow and replacement
of the losses of the bath from the first still rinse.  No
matter which rinsing  process you use, you will still be
getting  semi-concentrates,  which  can  be  handled as
shown. The effluent from the flow rinse goes to the ion-
exchanger and is then recirculated to the  rinse. With two
or three counter current flow rinses, the effluent from the
second and third rinses can be sewered  since the metal
concentration will  be under 5 mg/1, while the effluent
from  the first rinse  after  the bath  represents semi-
concentrates containing about 95% of all  metal losses.
Many other variations of this operation are possible.
Centralized Treatment and Disposal
Of Special Wastes in Bavaria*

   The following  discussion is an example  of  a  more
public and compulsory centralized treatment concept.

1. Tasks
   The harm caused  by the uncontrolled  disposal  of
commercial   and  industrial   wastes  has  become
increasingly  evident  in recent   years, owing  to  the
continuous growth of industrialization. Compared with
wastes from  households,  or domestic  refuse,  these
special wastes occur in relatively small quantities and
must receive special treatment in  plants designed for the
purpose  if they are to be  disposed of in the proper
manner,  i.e. with no harmful effects on  water, air or the
environment and with no adverse effects or pollution
caused by dust, odors or corrosive gases.
   Such materials, in the broadest sense, also  include
hospital wastes, scrap vehicles, car tires and the like; the
term  "special  wastes", however,  applies  only to  those
materials which, owing to their nature or quantity,
cannot be disposed of together with domestic refuse and
which none of the existing installations such as those of
hospitals,  animal carcass   processing  plants,  private
shredder installations, centralized  graveyards  for
radioactive materials, etc can take. The decision as to
what  constitutes  special wastes  depends both on  the
individual constituents of the material and on its quantity
M.xed B»d
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                             I De«Ot*re3 $lvX3g* to DiSpOSOl
                                                                            Water to Sewerage  I
           j—	->| Wottr  to Sewerage   j
Fig. 13—Schematic flow-sheet of a modern galvanizing plant.
                                                    110

-------
or  concentration since,  in general,  inert  industrial
sludges,   sandtrap  residues  and  oily  earth,   if  in
appropriate quantities can safely be tipped on controlled
domestic refuse dumps.

  Special wastes  are subdivided as follows:
• Materials such as  oil-contaminated soil, tar residues,
  solidifying acid sludges and the like which,  owing to
  their potential for air and water contamination, may be
  deposited at suitably prepared sites, subject to special
  precautions.
• Materials which can or must be disposed of by burning
  (e.g. solvents, used oil, oil wastes and residues, fullers'
  earth containing oil).
• Organic or inorganic  materials which must receive
  chemical or physical treatment before being disposed
  of. These include: acids,  alkaline solutions, sludges
  from the chemical and metal processing industries, and
  water-soluble heavy metal salts.
  Before the materials are treated, a sample is examined
in order to determine the type and effect of the process
which is  required and to check if the  customer has
marked the waste correctly. In general, treatment itself
consists of one or more of the following  processes:
• Neutralization  and decontamination;
• Thickening  and dewatering:  chemical/mechanical/
  thermal;
• Purification of  wastewater so that it can be discharged
  into a drainage system or receiving water course;
• Incineration
• Tipping, on domestic refuse tips/on specially prepared
  sites.

2. Bodies responsible for disposal of special wastes
  In Bavaria, the  problem of disposing of special wastes
received attention at an early stage and it was found that,
only  a broadly-based solution made economic  sense.
owing to the technical and financial  resources needed to
build and  operate the requisite plants, which had  to
satisfy the requirements of public health  and  order,
particularly  those  concerning preventive  measures
against emissions and water pollution. The initial idea
was to entrust the task to the bodies already engaged in
the  disposal of special wastes at regional levels and  to
extend this over the  whole "Land," but it then became
apparent that a joint body responsible for special waste
disposal  comprising  public  and local  authorities and
commercial firms  would be the best solution in Bavaria.
  Thus the end   of  1970 saw the founding of the
"Gesellschaft zur Beseitigung  von  Sondermull   mbH
(limited company for the disposal  of  special  wastes),
"GSB" for short, with a capital of DM 1 million, 40% of
which was provided by the Bavarian authorities, 30% by
the  three leading  local authorities and 30%  by  25  firms
from  the  chemical,  metal processing, paper  and  oil
industries in Bavaria. (By additions to capital in  1975,
1977 and 1979, the present sum is DM 20.93 million, the
number of firms has now risen to 74, an increase of 49).
The company's purpose is to dispose of or recover in a
correct manner the special wastes arising in Bavaria and
to engage in related  activities. This serves  the public
interest and is not intended for  profit.
  The company, which operates as a private enterprise
and is required only to cover its costs, is responsible for
building and operating the installations needed for its
work. In so doing, it must specialize in taking delivery of
those wastes in which private waste disposal contractors
generally  have   little  interest  because  they   are
unprofitable, and must introduce and apply methods for
the  proper and  economical  disposal,  processing  or
recovery of wastes specific to certain industries.
  The fact that the GSB does not have to make a profit
on  waste  disposal  and  that  the supervisory  board
representing the members of the company has to approve
the disposal  charges means that conditions now exist
which enable commercial and industrial concerns  to
deliver their wastes to the GSB and have them properly
disposed of in accordance with the law, without the need
for coercion. In this connection, the high public authority
holding (over 75%)  of the company's stock and  the
resulting priority given to safety provide a guarantee of
optimum environmental protection in the building and
operating of plants and in the treatment of materials.
Companies  modelled  on  the GSB,  with  a similar
composition and identical aims and tasks, have now been
set up.
  The GSB began its work on 1 March 1971; firstly, an
overall  approach  to the  disposal of special  waste  in
Bavaria was  worked out  and then  the  extension  of
existing plants and the construction of new facilities was
planned and put in hand.

3. Disposal plants and collection  sites
  In  view  of the  economic structure  and the size  of
Bavaria, it is planned to establish three central treatment
plants and a  network of collection sites in areas where
arisings of special wastes are greatest.
  The disposal plants provide facilities for pretreating,
incinerating and tipping wastes; they are equipped with
dewatering, neutralization,  detoxification and  water
purification plants, including sludge thickeners, filter
presses  and  emulsion  separators, as  well  as mixing
installations and, finally, officially-approved landfill sites
which are carefully operated to avoid odor emissions and
whose waste water is collected in  observation tanks for
monitoring.

3.1   Schwabach disposal plant
  This  plant  is  run   by  the   "Sweckverband
Sondermullplatze Mittelfranken" (ZVSMM), which was
set  up in 1968 and  disposes  of  special wastes  in  the
administrative district of Middle Franconia. It is located
conveniently   near  the  Nuremberg  Furth/Erlangen
industrial zone and contains an incinerator plant  with a
capacity of 9 Gcal/h, a physicochemical treatment plant,
a  wastewater  purification  plant and  an  officially-
approved landfill site with a capacity of 500,000  m-1.

3.1.1   Commitment
  The industry in  Middle  Franconia  has  taken a
favorable   development  during  the  last  20  years.
  The large   quantities of  wastes  occuring in  this
production  sphere could  not,  due  to  the  difficult
character, be integrated  into domestic refuse disposal.
  This special department was thus established in 1966
and is dedicated to solving these problems in the common
interest as a nonprofit organization.
  The administrative association is  a corporate body
incorporated  under public law.

3.1.2   Members of the Administrative Association
  Members of the administrative association are: the
cities of Ansbach, Erlangen,  Fuerth,  Nuernberg  and
Schwabach, not incorporated in a county; the counties of
Ansbach,   Erlangen-hoechstadt,  Fuerth,
                                                    111

-------
Neustadt/Aisch-Bad Windsheim, Nuernberg rural area,
Roth, Weibenburg-Bunzenhausen; the large county city
of Weissenburg in Bavaria; the cities of Lauf a.d. Pegnitz,
Roethenbach a.d. Pegnitz, Roth Stein; the community of
Neunkirchen a.S.

3.1.3  Catchment - Area
  The  operational territory is  the whole  district of
Middle Franconia.
  The official catchment area covers in addition:
a) in the district of Upper Franconia: six counties and
three cities, not incorporated in a county.
b) in the district of the Upper-Pfalz: three counties and
one city,  not incorporated in a county.
c) in the federal state of Baden- Wuerttemberg:  eight
counties.
Total Catchment .area:
25,000 square kilometres =
  10% of the area of the Federal Republic of Germany

3.1.4  Efficiency of the  Schwabach treatment-complex
  A composite  unit comprising laboratory, landfill site,
water treatment plants and incinerator, the Schwabach
treatment-complex  receives  110.000  tons  of special
wastes per year.
  From this quantity, 40 percent are dumped in the
specially-designed special wastes dump, 25% are treated
in the  decanting plant  with an  emulsion  separating
system,  20  percent are treated  in the  detoxication-
neutralization-and dewatering plant and  15 percent are
incinerated.
  The working procedure at Schwabach is to put all
loads received over the  weighbridge on arrival, and to
take a   sample  immediately.  Analysis  is  normally
completed within 10 minutes, and on the basis of this, the
waste is  directed to the incinerator,  to  the treatment
plants or direct to the landfill site.
  Where direct landfill disposal is  not possible, oil and
water are separated, so  that the oil can be incinerated,
while water is treated before discharge into a watercourse
adjoining the site. Chemicals are treated and neutralized.
  The sludge dewatering plant is able to  handle sludge
arising  from  galvanizing  operations.  After
detoxification, dewatering and neutralization, the water
obtained from press filtering must pass a recording pH
meter check  prior to being  introduced into the public
drains. The spadable filter cake  can then  be disposed of
in the special wastes dump.
  Until  now over 5,000 experts  from  29  countries
have visited  the Schwabach treatment-complex.
  The treatment plant installed at Schwabach was taken
as an example for similar plants in the Federal Republic
of Germany and in foreign countries.

3.2.  "Sud" disposal plant
  The Sud  disposal plant of the  GSB, situated in the
Munich/Augsburg/Ingolstadt area,  consists  of  two
associated sections constructed along the latest technical
and economical lines; the first, consisting of mechanical
facilities, is  at  Ebenhausen, near Ingolstadt, and the
second, i^he Gallenbach landfill site for special wastes, is
situated in the  rural district of Alchach-Friedberg. The
separation of the two sections, which lie about 40 km
apart,  is due to  the difficulties  now experienced in
purchasing land for plants of this  kind.
   After much detailed  planning and  a relatively  short
construction period, the Sud disposal  plant started
operating at the beginning of 1979.
3.2.1   Ebenhausen mechanical installations
  The Ebenhausen plant, built on a site about 4 hectares
in area, contains the following: a general-purpose section
with a vehicle weighing machine, a workshop and store-
rooms; an administrative building housing offices, staff
facilities  and the  fully-equipped central laboratory; an
incinerator plant for liquid, semi-liquid and solid wastes;
a physicochemical  treatment plant for used  alkaline
solutions, used acids,  plating sludges, inorganic sludges
containing chromium, cyanide and nitrites; and a plant
for  purifying industrial wastewaters.
  The incinerator plant on  the eastern side of the site
contains  two rotary furnaces, a steam generator, and  a
highly-expensive flue gas purification plant consisting of
electro-filters and two-stage flue gas scrubbing  plant,  a
turbogenerator  and  all   the  requisite  auxiliary
installations. Its heat  output is 25 Gcal/h  - 12.5 Gcal/h
from each of the rotary furnaces and the liquid burners.
  In this way it is possible to operate simultaneously
either two firing systems at full capacity or  three systems
at reduced capacity. The planning allows for the addition
of a further unit of the same type.
  The firing installations  are followed  by the  large
secondary   combustion  chamber  in   which  the
temperature is kept  at a minimum of 1000° C. The flue
gas  is then cooled to about 280° C in a steam generator
with exclusively smooth-walled pipes  to inhibit sooting
of the heating surfaces and a switchback configuration in
order to  increase the separation of solid constituents
from the flue gas  flow.
  The flue gas cleaning system consists of an electro-filter
for  separating out fine dusts and a two-stage scrubbing
plant for removing chlorine, fluorine and  SO2 from the
flue gases. The scrubbing water  is  recirculated and is
treated in the physicochemical plant.
  The steam which is produced (32t/h, 25 gauge atm.) is
used both to produce electrical energy for the plant's own
use and to heat the plant's installations. Surplus  steam is
condensed  in an air-cooled heat exchanger to avoid
polluting the environment.  An oil-fired  boiler with  a
large  water space (6 Gcal/h) is available  for supplying
heat when the incinerator  is out of operation.
  The control room and the power supply installations
such as switchgear,  a transformer, a  turbogenerator,  a
feedwater treatment plant and a boiler are housed in  a
central situated building. The receiving bunkers for solid
and semi-liquid wastes  and the  loaders for the rotary
furnaces are roofed in  while all the remaining parts of the
plant are in the open.
  In  the  physicochemical  treatment plant  (CPA),
situated in the western half of the site, the materials are
put in one of the eleven 30 m3 receiving tanks, depending
on  the results of  the  laboratory tests. These tanks lead
into several  storage  tanks  of the same capacity and,
finally, these are  followed by the individual treatment
plants consisting of mixing and dosing units.
  Any sludge which is produced is  drained in chamber
filter presses, the filter cakes are taken to be dumped and
the filtrate as well as  other waste water is  discharged to
the receiving watercourse or to a sewage treatment plant
via final  inspection  points and retaining vessels.
  Pollutants are removed by a gas scrubber to which the
contaminated air  and  waste  gases from the containers in
the  CPA  are  conveyed.  The purification  plant  for
industrial waste  waters containing  oil and emulsions
(ARA), which is integrated  into the CPA  and has been
                                                     112

-------
 developed by the GSB, consists of two tanks with a
 capacity of about 300 m3, a centrifuge, a mixing  and
 dosing unit, and a vacuum drum filter.

 3.2.2  Gallenbach landfill site (Figure C)
   The site, about 17 ha in area situated near the Munich-
 Stuttgart motorway on Federal highway No. 300 leading
 to  Ingolstadt, is crossed by a layer of  clay and loam
 between 8 and  18  m thick  which prevents  water from
 seeping into the lower groundwater table.  Above  this
 layer there are moraine deposits, gravel and sand, which
 are gradually being removed and used to construct each
 section of the site. In contrast to those collection sites for
 which existing trenches are usually chosen, here the earth
 pits have to be dug.
   This  produces  a sufficient quantity  of excavated
 material for covering purposes, such material often being
 difficult to obtain in other circumstances. Since the outer
 slopes are planted and grassed while the landfill site is
 being constructed,  the appearance of the landscape  is
 altered only for  a relatively short time. The inner surface
 is covered with  a clay/loam puddle layer at least 40 cm
 thick which acts as a sealing material. The leachate  is
 received  by drainage courses with a filter gravel  base
 about 2 m beneath the pit bed and, like the surface water,
 is conveyed to three retention tanks with a total capacity
 of about 10,000  m3. When a tank is full, the water in it is
 inspected and, if found to be in satisfactory condition , is
 discharged to the receiving  watercourse. If  it does  not
 meet the discharge requirements,  it is  retreated  and
 transported  to a sewage  treatment plant.  The
 groundwater is  continuously monitored by means of
 sampling tubes reaching down to the lower groundwater
 table.
  The landfill site for special wastes has a gross storage
 capacity of about 1.5 million m3 and will take about 15 to
 20 years to fill. In addition, it includes an administrative
 building  with an office, staff accommodation, a testing
 room, a  shed for earth  moving  machinery and other
 vehicles,  and a vehicle weighing machine.
  The first section, completed in 1975  in only nine
 months,  has a storage capacity of 450,000 m3.

 3.3  Schweinfurt disposal plant
  The third disposal plant is situated in Schweinfurt. At
 present, it is an incinerator  plant for industrial wastes
 which are similar to  domestic refuse  (heat output of
 about 9 Gcal/ h) and was purchased by the GSB at the end
 of   1972  from  the  former  "Sweckverband   fur
 Abfallbeseitigung in der Stadt Schweinfurt" (association
for waste disposal in Schweinfurt). Since then, further
installations have  been  added so that  it can receive
further wastes.
  In the  long term, it is planned to replace the present
plant with an incinerator plant for liquid and semi-liquid
wastes (with the  same heat output of 9 Gcal/h).

3.4  Collection sites
  The collection sites for special wastes,  where various
wastes from nearby firms - often in small quantities - are
delivered  and temporarily  stored,  help among other
things to reduce  transport costs (an important factor in
view of the size of Bavaria, which covers one third of the
area of the Federal Republic) by the combination and use
of  convenient   bulk  transport  vehicles  and  by  the
existence of a standard list of charges for the whole Land
in order that firms situated outside the main industrial
centres should not be placed at a  disadvantage.
   The collection sites are designed on uniform lines and
 generally contain the same equipment. Apart-from the
 temporary storage of waste, they are also responsible for
 pretreating as much waste as possible and for reducing its
 volume  with  the  aid  of easily-operated  technical
 installations.  They  contain waste  water purification
 plants (ARA), in which the consistently large quantities
 of oil/water mixtures that are delivered are separated out
 into oil, water and solid matter. The purified waste water
 is immediately drained off. What remains, less than 10%
 of the original amount, is in the form of an oily sludge
 which is then transportec elsewhere.
   When justified it is planned to install  neutralization
 and,  if  necessary,  sludge  thickening equipment.
 Furthermore, in  addition to an administrative building
 with a testing room and a vehicle weighing machine, all
 collection  sites have adequate storage  space for oil-
 contaminated earth and for freight containers designed
 to collect and temporarily store industrial sludges of all
 kind.
   Collection  sites already  exist   in  Aschaffenburg,
 Augsburg, Mitterteich,  Munich, Neu-Ulm, Passau and
 Straubing. Within the  next few years it  is planned to
 construct  further  collection  sites  in  Bamberg  and
 Kempten and a new large-scale site in Munich.
   The  GSB  keeps  in  close  contact   with  all  the
 organizations which are concerned with the planning of
 new disposal plants for domestic refuse or sewage sludge
 in order  that new plants (incinerators and landfill sites)
 are,  wherever possible,  designed and constructed from
 the outset  so that they can dispose of special wastes.
 Thus, for example, oily sludge with a high calorific value
 which is brought  to the collection site is ideally suited to
 back up  the burning of sewage sludge, a process which
 will become increasingly important in the future. In Neu-
 Ulm, combined  operation of  this  kind between  a
 collection site and the incinerator unit of a neighboring
 sewage treatment plant  is already taking  place. Efforts
 are also in  hand to set up a joint operation between the
 collection sites and domestic refuse  incineration plants
 which are to be built in Bamberg and Kempten, in order
 that  part of the wastes can be disposed of on the spot.

 4.  Recovery plants
  At the Ebenhausen incinerator plant, heat and electric
 power (for the plant's  own use) are derived from the
 wastes and converted into usable form. The incineration
 of wastes with a high calorific value which occurs in
 Sohweinfurt  is also of benefit since it  enables non-
 combustible materials to be disposed of more efficiently
 and at less cost.
  As a result of the recognition that raw materials have to
 be used more sparingly  in future, the main emphasis in
 waste disposal is shifting  increasingly to  recovery and
 reutilization.
  This led the GSB, at the end of 1973, to take various
 steps, including  the  purchase of a firm situated  at
 Gereteried, near  Munich, which was engaged  in  the
distillation of used solvents, varnish thinners, degreasing
agents and  similar materials, to ensure that the recycled
materials were put back on the market.

 5. Deliveries and transport
  Disposal of special wastes can be effective only when
these materials are clearly  described  and when their
 transport is supervised.  To this end, in addition to the
form specified by the authorities, the GSB also  issues
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numbered forms consisting of several  sections which
must be completed and officially signed by the producer
(or originator) of the waste. When the waste is handed
over to a haulier, the customer retains one copy of the
form as a receipt whilst the remaining copies, the contract
and the confirmation of the contract are  delivered along
with the wastes to one of the GSB's offices; the hauler
retains the other copy which enables him  to present a bill
for his services. Before the vehicle is emptied, the details
given by the customer are checked, as is  the amount (by
weighing) and  the  description  of the materials  are
checked by  means of the serial numbers on the forms
which have been issued. The costs of disposal incurred by
the GSB are charged directly to the producer of the waste;
normally the GSB does not accept  orders for waste
disposal from haulers. The GSB also refuses to accept
delivery if the form is not properly completed or if the
conditions  under which  delivery is accepted have  not
been observed.
  The transport  of special  wastes   falls into  two
categories;  the  delivery  to  the  collection site  (the
"collection  service") and the conveying of the wastes by
bulk transporters from the collection site to the disposal
plant.
  The "collection  service" is generally performed by
efficient and reliable private haulage firms which, when
the customer does not make  the  delivery himself,  also
represent a guarantee that the wastes will arrive at the
collection site. Bulk transport between the collection site
and the disposal plant is normally carried out in freight
containers or tankers in cooperation once  again  with
private hauliers.

6.   Amounts of waste received and capital expenditure
  The growth of the GSB over the last few years can be
seen from the following figures on  deliveries of special
wastes:
 Year:
 Amount:
1972
 60
1973
116.5
1974
134
1975
165
1976
171.6
1977
186.4
1978
183.1
  Last year the GSB and the ZVSMM duly disposed of a
total of 300,000 t of special  wastes in Bavaria.
  By  the end  of  1978, the construction of the above-
mentioned installations had  cost about DM 80 million,
towards  which the Bavarian  authorities  contributed
generous "Land" grants and  low-interest  government
loans.

SUMMARY
  In this paper I have attempted to outline in examples
the treatment  being used for different  wastes  from the
metal finishing and other industries.
  I hope that those who are struggling with  the same
problem will find this description useful.
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          EPA's  Centralized Treatment Program
                             Alfred B. Craig, Jr., and George C. Cushnie Jr.*
 INTRODUCTION
  The Metal Finishing Industry utilizes more than 100
 surface finishing and fabricating operations that require
 aqueous  application and removal of various metals to
 and from metallic and plastic parts. The metal finishing
 process baths contain various  cyanides and cyanide
 complexes, hexavalent chrome, copper, nickel, zinc,
 cadmium, and other metals that must be disposed of once
 the end of the useful life of the bath has been reached. In
 addition, water used to rinse plated parts contains dilute
 concentrations of these metals.
  A vast majority of electroplating shops reside in large
 industrial communities in and around municipalities. A
 majority  of the plants in the electroplating industry
 discharge untreated or lightly treated rinse water and
 plating baths to municipalities for treatment by Publicly
 Owned  Treatment  Works  (POTW's).   These
 nonbiodegradable pollutants are discharged in millions
 of  gallons  of process water each  day to  biological
 treatment systems, which are ineffective for treating such
 wastes.
 Impacts  of  Metal Finishing Operations on Publicly
 Owned Treatment Works
  Pollutants  in metal finishing process   wastewater
 interfere with proper operation of biological systems and
 restrict the  utilization of biological  sludges because of
 their  high metal content. Cadmium,  chromium, lead,
 nickel, and zinc are not destroyed when introduced into a
 POTW and will either pass  through the system  or will
 contaminate the sewage sludge. The metal content of this
 sludge may preclude land application of sewage sludge on
 food crops; sewage sludge disposal by incineration is also
 questionable because  of the  volatility  of cadmium and
 lead.

 The Enabling Regulations
  The Environmental Protection Agency  is currently
 proposing and  promulgating  a scries of  industrial
 wastewater pretreatment regulations. These regulations
 will reduce the  introduction of industrial wastewater
pollutant parameters  to POTW's. In order to comply
 with these pretreatment regulations, indirect dischargers
will be required to install various process wastewater
control and treatment technologies at their  plant sites.
These regulations, will cause adverse economic impact on
'Alfred B. Craig, Jr.
 Nonferrous Metals & Minerals Branch
 Industrial Environmental Research Laboratory
 U.S. EPA, Cincinnati, Ohio
 George C. Cushnie, Jr.
 Centec Corporation
 Reston, Virginia
some industries  and some small plants with limited
personnel and capital for addressing these regulations
undoubtedly will be forced to close.
  Simultaneously,  EPA  is  implementing  Congress'
intent of the Resource Conservation and Recovery Act
(RCRA). Industry, in complying with the provisions of
RCRA, will be required to safely dispose of their residual
wastes. The cost of waste disposal and management will
likely increase as will administrative burdens associated
with the proposed waste management system.
Research on Centralized Treatment
  Three years ago,  EPA's  Office of  Research  and
Development (ORD), anticipated the potential impact to
industry  resulting  from  compliance  to  pending
wastewater and solid waste  regulations. Therefore, it
began  investigating conceptual alternatives  to on-site
industrial waste treatment by generators. One promising
alternative  is centralized treatment. The primary assests
of this approach are scale economy and improved waste
management.  Centralized  treatment  provides
experienced management and personnel whose primary
responsibility is in handling wastewater and solid waste
residuals; this contrasts with production personnel who
can provide only intermittent supervision of treatment
practices at individual industrial plant sites.
  ORD has taken an active role in investigating the
Centralized  Waste  Treatment (CWT)  concept,
determining its applicability to  the metal  finishing
industry,  and   laying  the  groundwork  for
implementation. An ORD project in 1977 established the
economic feasibility of a joint waste treatment plant and
investigated the  legal and institutional arrangements
necessary for successful implementation and operation.
In  1978,   ORD   sponsored  a  second  project that
investigated  the   successful centralized  treatment
application in the Ruhr Valley in Germany. This same
project explored the applicability of CWT to the United
States   taking into  account U.S.  costs  and  U.S.
environmental requirements.
  In June of 1979, a third project  was funded by ORD.
This project, which will be completed within 3 months,
has developed the background information for industry
implementation of  centralized  treatment.  A manual
describing technical, economic and financial aspects will
be issued in July. The remainder of this paper will be
devoted to the current EPA Centralized  Treatment
Program effort. An explanation of project objectives and
procedures and a summary of available  results will be
presented.

CWT PROJECT OBJECTIVES  AND OVERVIEW
  The current project is divided into two phases. The
purpose of Phase I is to determine the conditions that are
favorable to CWT development and  to identify which
areas of the U.S.  meet these conditions.
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  The first task of Phase I comprised a categorization
process  that  defined characteristics  that  affected  the
feasibility and design of a CWT system. Then, five case
studies were chosen to represent varying situations in
which CWT  would be  applicable.  To  determine  the
feasibility of CWT in each of the case study areas, data
were  gathered from  municipal, regional, and industrial
sources, and an analysis was performed.
  The  purpose  of  Phase  II was  to  develop  and
demonstrate the approach necessary for implementation
of central treatment. This was accomplished by selecting
one  promising area and  developing a comprehensive
metal finishing waste control plan that includes a CWT
system  configuration with collection, transportation,
treatment and disposal; on-site treatment requirements;
financing  requirements   and   alternatives;  and
management options.
Phase I -
Categorization and CWT Feasibility Case Studies
  The activities of Phase I were focused on the selection
                          and analysis of the five case study areas. The procedure
                          for Phase I included six major tasks:
                            • Categorization  of   U.S.  metropolitan  areas
                          containing a substantial metal finishing population
                            • Selection  of 24 metropolitan  areas for case study
                          consideration
                            • Selection of five case study areas
                            • Data collection and characterization  of case study
                          areas
                            • Development of analytical tools
                            • Case study analysis of CWT feasibility

                          Categorization of U.S. Metropolitan Areas Containing
                          Substantial  Metal Finishing Population
                            A statistical categorization process was used in Phase I
                          so that the results of the five case studies could be applied
                          to a major portion of the metal finishing industry across
                          the U.S. within characteristic regions. The basic premise
                          behind this  categorization was that if a case study had a
                          feasible solution for CWT, then all cities in the same
                                                      Table 1
                                       Factors for Developing Categorization
Factors Affecting Feasibility and
Design of CWT
                           Probable Effect of Factor
GOVERNMENTAL FACTORS
• Willingness of Municipalities to
   Participate in CWT
• Future Plans of Municipality with
   Respect to Industrial Discharges
• Availability of Disposal Sites
• Number of Local Governments
   Involved
• Non-Federal Regulations

• Type of Municipal Government

• Municipal Willingness to
   Fund CTF
• Municipal Financial Conditions

• Municipal Demography
 Participation and cooperation by municipal governments will hasten the implementation of
 CWT; however, a strong private interest in CWT may overcome municipal barriers.
 Municipalities with immediate plans to enforce pretreatment will reduce feasibility of CWT.

 CWT is more likely to be feasible in localities containing disposal sites.
 A large number of local governments will present a less feasible situation, since jurisdic-
 tional disputes will be a barrier to CWT. If a league of cities exists, the effect of this factor
 may be mitigated.
 Local pretreatment regulations may have already precluded CWT by forcing  individual
 treatment to be presently installed.
 Various types of municipal government structures should be investigated. At this time,
 the effect of this factor is uncertain.
 Municipal funding may be necessary in certain areas; however, private funding may
 eliminate the effect of this factor.
 Some cities may qualify for Federal assistance in constructing a central treatment facility
 (CTF). Some cities may be able to affort CTF or be able to raise money through bonding.
 Population size and density will affect the availability of land for CTF and disposal siting.
 Also, cities with a high population concentration may have traffic congestion that increases
 hauling time and, therefore, CWT costs.
INDUSTRIAL FACTORS
• Number of Metal Finishing
   Plants
• Concentration of Metal
   Finishing Facilities
• Willingness of Metal Finishing
   Industry to Participate in CWT
• Total Wastewater Flow
• Present Treatment Installations
• Future Plans of Metal
   Finishing Industry
• Types of Waste

• Types of Metal Finishing
   Industry
The number of plants may affect the design of the CTF. Also, larger numbers of facilities
will favor CWT.
Higher concentrations of facilities will favor CWT.

Without the minimum number of customers required to reach economies of scale, CWT
will not be feasible.
Minimum flow needed for feasibility of CWT.
Installed treatment facilities may preclude CWT.
Immediate plans to install pretreatment may preclude CWT.

The type of waste affects the design of the CTF. Also, CWT is most amenable to
concentrated metal-bearing wastes.
The type of industry affects the waste characteristics and, therefore, the design of the CTF
and feasibility of CWT.
 GEOGRAPHIC FACTORS
 • Regional Location
Most segments of the metal finishing industry are unevenly distributed. For example, the
jewelry industry is concentrated in the Northeast, and the electronics industry is in the
Southwest and Far West. This factor will affect the design and feasibility of CWT.
                                                        116

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 category  should result in a  similarly feasible  CWT
 scheme.
   The initial  step  in developing  the categorization
 scheme was the  identification  of factors that were
 expected to affect the feasibility and design of a CWT
 system. These factors are listed in Table 1. The next step
 was to develop quantifiable  categories  utilizing  the
 factors. A simple solution to categorization would have
 been to designate each metropolitan area as a category.
 This could be done easily, since all possible combinations
 or permutations of the various factors would produce a
 very large number of potential categories. This, however,
 would defeat the purpose of categorization, since results
 from one municipality could not be applied to others.
   To avoid the problem of too  many categories, four
 major factors were  used  to define   the   initial
 categorization scheme (Table 2).
                         Table 2
             Municipal Categorization Scheme

    Category 1      Category 2     Category 3
    Bridgeport
    Hartford
    Att/Taunton

    Syracuse
    Category 4
    Providence
 Rochester
 Erie
 Baltimore
 Worcester
 Springfield
 Buffalo
 Pittsburgh
 Category 5
 Boston
 Philadelphia
 New York
 Newark
 Trenton
 Silver Spring
 Camden
 Manchester

 Allentown
 Arlington
 Reading/Lancaster
 Harrisburg
 Long Island
    Category 6     Category 7     Category 8
   Atlanta
   Miami
   New Orleans
   San Antonio
   Orlando
 Houston
 Dallas/Ft. Worth
Canton
Ann Arbor
Kalamazoo
South Bend
    Category 9     Category 10     Category 11
   Milwaukee
   Cincinnati
   Grand Rapids
   St. Louis
   Indianapolis
Tulsa
Kansas City
Toledo
Columbus
Oklahoma City
Rockford
Ft Wayne
Chicago
Cleveland
Detroit
Minneapolis/St. Paul
   Category 12     Category 13     Category 14
   San Francisco
   Los Angeles
   Fullerton
Seattle
Denver
Alburquerque
San Diego
Portland
Honolulu
Phoenix
San Jose
Riverside
Ontario
Santa Barbara
  These major factors include:
  • Number of local governments
  • Municipal demography
  • Number of metal finishing facilities
  • Regional location
  Aside from their relative importance, these particular
factors are closely related to the other factors identified in
the  categorization  step;  therefore,  the   resultant
                                         categorization  scheme  actually encompasses a  broad
                                         range of factors. For example, the regional location of a
                                         metropolitan area is closely related to the type of industry
                                         and the type of waste since particular segments  of the
                                         metal finishing industry tend to concentrate in particular
                                         regions. Similarly, the number of metal finishing facilities
                                         is closely related to the  concentration of metal finishing
                                         facilities.
Selection of  24 Metropolitan Areas  for  Case Study
Consideration
   In the selection process, it was assumed that the best
choice of metropolitan areas would be those where a need
exists and where municipal cooperation can be expected.
Also, it was believed that  all EPA Regions should be
involved in the next stage of the CWT project. To satisfy
these assumptions, the following criteria were used in the
selection process:
   •  Choose all localities that have shown a willingness to
participate in a CWT project
   •  Choose  mostly metropolitan areas with  a large
number of metal finishing facilities
   •  Exclude localities that have pretreatment programs
with  stringent  regulations for  the  metal finishing
industry.  (If  stringent local pretreatment  regulations
were currently  in  effect,  it   might  preclude  the
establishment of a central treatment facility since plants
may  already  have  committed  to  individual waste
treatment.)
   •  Choose  localities with a  relatively small ratio of
population  to  number of  electroplaters.   (This  is a
simplified measure  of the economic dependence  of a
particular area on its metal finishing industry.)
   •  Choose at least  one metropolitan area per category.
   •  Choose at least one locality per EPA Region.
   The selection process resulted in the choice of 24
metropolitan areas. These are listed  in Table 3.
                                                               Table 3
                                             Metropolitan Areas Chosen for Further Study

                                                  Category     Metropolitan Areas
 1
 2
 2
 3
 4
 5
 5
 6
 6
 7
 7
 8
 9
 9
 2
10
10
11
11
12
13
13
13
14
                       Bridgeport
                       Rochester
                       Erie
                       Trenton
                       Providence
                       Boston
                       Philadelphia
                       Atlanta
                       Miami
                       Houston
                       Dallas/Ft. Worth
                       Canton
                       Milwaukee
                       Cincinnati
                       Buffalo
                       Tulsa
                       Kansas City
                       Chicago
                       Cleveland
                       San Francisco
                       Seattle
                       Denver
                       Albuquerque
                       San Jose
                                        Selection of Five Case Study Areas
                                          The first step in the selection process was to formulate
                                        a group of criteria that reflects the desired qualities of a
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case  study  area.  These  criteria  included  technical,
economic,  political, and administrative considerations
(Table 4). The 24 candidate case study areas were then
visited to  collect information related to each  of the
criterion.
  The actual selection was performed by using a decision
process that  quantitatively evaluated how  well  each
candidate area satisfied the  various criteria. Those areas
that were best suited to the decision criteria were then
selected.
  The decision technique that was  utilized is termed
worth assessment. With this method, an analytical model
is developed that allows any number of decision criteria
to  be used  in a  selection process.  The criteria are
quantitatively weighed (0 to  1, with the total weights of all
criteria equaling 1) to reflect their intended importance in
the  decision.  Then,  for  each  candidate,  a  worth
assessment  score is  calculated by:  (1)  evaluating  or
scoring on a scale of 0 to  1  how  well each candidate
locality satisfies each criterion, (2) multiplying the score
for each criterion by its weighted value, and (3) summing
over all criteria.
  Several criteria, such as municipal cooperation,  were
given overriding  consideration because they could  limit
the success of this project and CWT for that region.
Therefore  when certain constraint  criteria were not
satisfied, the entire worth assessment score for  that
particular locality was assigned a value of zero.
  The worth assessment exercise resulted in the scores
and case study selections shown in Table 5. As indicated
in  Table 5, the metropolitan area  of Philadelphia was
chosen although both Denver and Buffalo  scored higher
in  the analysis.  This was  done because  of the  small
difference in scores and the fact that the categories (Table
2)  which contain Denver and Buffalo  would already be
represented  by Seattle  and  Milwaukee,  respectively,
which had  been likewise chosen.
Data Collection and  Characterization  of Case Study
Areas
  The data necessary  to  evaluate  the  feasibility and
design of CWT was collected via visits to municipal and
regional authorities, such as POTW's, in each of the case
study areas and through the use of an industrial survey.
  The basic philosophy used in data collection was to
first gather as much available information as possible
from municipal and regional authorities.* The additional
data necessary for a feasibility analysis was collected
from industry via an industrial survey. The survey was
distributed to metal finishing companies in the five case
study  areas  by the American Electroplaters'  Society
(AES). Once completed and returned to AES the survey
responses were forwarded to the  centralized treatment
study  project team to be compiled and  used for the
feasibility analysis.
  Information and data from  local governments and
industry  were combined to characterize each of the case
study areas. All metal finishing facilities which discharge
wastewaters were mapped along with potential central
waste  treatment  sites  and  landfills.  Effluent data and
information  concerning installed waste  reduction  or
treatment  equipment for each metal finishing facility
were compiled. Transportation routes were defined for
shipping wastewaters and sludges from metal finishing
plants to the potential central sites and the landfills.

Development of Analytical Tools
  A mathematical model was developed to evaluate the
feasibility of CWT and to determine the configuration of
*Government sources were generally able to supply the following types
 of pertinent data and information: metal  finishing shop location,
 water use and effluent concentrations for  metal finishing facilities
 discharging to POTW's; location and ownership of landfills accepting
 metal bearing sludges; and location, size, and zoning classification of
 land tracts that could serve as sites for a centralized treatment facility.
Table 4
Case Study Selection Criteria
Area of Impact
Criteria
Municipal Cooperation with
Project Personnel
Present Local Pretreatment Regulations
Availability of Disposal Sites
Number of Municipalities in
Metropolitan Area
Number of Sewer Authorities in
Metropolitan Area
Local Plans for Enforcing Future
Regulations
Economic Impact (Ratio of Population
to Number of Metal Finishing
Companies
Concentration of Metal Finishing
Companies
Current Availability of Central
Waste Treatment
Number of Metal Finishing Companies
in Metropolitan Area
Technical
•
•
•


•

•
•
•
Economic






•
•
•
•
Political

•

•
•
•




Project
Administration
•

•
•
•


•

•
                                                      118

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Worth Assessment
'Milwaukee
'Seattle
'Cleveland
'Atlanta
Denver
Buffalo
'Philadelphia
Trenton
Miami
San Francisco
Erie
Tulsa
Chicago
Dallas/Ft. Worth
Canton
Kansas City
Boston
Rochester
Cincinnati
Houston
San Jose
Albuquerque
'Areas Selected
Table 5
Scores For Case Study Analysis
0.684
0.639
0.638
0.634
0.634
0.622
0.618
0.574
0.532
0.532
0.503
0.503
0.444
0.418
0.404 ,
0.398
0.342
0.325
0.300
0.286
0.
0.
*jl\
a CWT system for each of the case studies. The model is
capable of simulating cost effective alternatives for given
scenarios considering various options involving in-plant
flow reduction, waste concentration, on-site treatment,
and shipment to a centralized treatment plant.
  The model was programmed in the efficient-structured
language,   Pascal,  with  the   intention  of  using  a
microcomputer  for the  analysis. Descriptions of the
model components, data input procedure, and logic flow
follows.
Technical  Basis of Computer Model
  The model considers three typical raw waste streams
generated  by the metal finishing industry:
  • Rinse waters and spent baths containing chrome
  • Rinse waters and spent baths containing cyanide
  • Other acid/alkali rinse waters and spent baths
  It is assumed that these wastewaters are segregated into
discrete streams  to  allow for separate treatment of
chrome and cyanide.
  Rinsing operations account  for over  90  percent of
water used by a typical  plating facility; however,  this
water  use can  be drastically  reduced  through  the
installation  of  efficient rinse  techniques  such  as
countercurrent rinses,  series rinses, spray rinses, and still
or dead rinses. A reduction in water use will benefit shops
by reducing the necessary capacity of waste  treatment
processes or the amount of wastewater to be hauled to a
Central Treatment Facility (CTF).
  To  reflect the potential application of flow reduction,
the   model  is   programmed   to  consider  the  cost
effectiveness of converting single running rinses to two-
stage  countercurrent rinses. Other techniques, such as
dead  rinses  or ion exchange  could also be used for
concentrating rinsewaters; however, for this first analysis
only countercurrent rinsing was considered. The use of
other techniques will be investigated during latter stages
of the project.
  The cost  of converting to countercurrent rinsing is
assumed to be $3,000 based on the addition of a 5-foot by
6-foot by 4-foot tank,  the appropriate plumbing, and an
air  agitation system.  The  countercurrent   system  is
assumed to reduce the original single running rinse water
use by greater than 90 percent.
   Many shops will be unable to install an additional rinse
tank  because  of  space  limitations  or  the use  of
programmed hoist lines. In  these cases, it is assumed
there is no potential for substantial flow reduction.
   It is also possible for many shops to reduce rinse water
usage  through inexpensive,  good  water conservation
measures such as flow control valves. During the course
of the study, it was observed that most shops are using
much more than is necessary to protect product quality;
therefore, an additional factor  was considered in the
modeling exercise to account for these types of water
conservation. It was assumed that tanks without flow
control valves  would  reduce flow  by 50 percent with
minimal capital costs.
   Conventional  technologies   were   considered  for
treatment of wastes.* These technologies could be used
either on-site or at the CTF. The possible waste treatment
processes included:
     Chrome reduction
     Cyanide oxidation
     Physical /chemical treatment
     Sludge dewatering
     Storage  (on-site only, to be  used for plant selecting
CWT options)
   Waste streams with a chrome concentration above the
1982 pretreatment standards  (Table 6)  would be subject
to  chrome  reduction.  Similarly,  wastewaters  not
complying with cyanide pretreatment  standards would
be subject to cyanide oxidation. The effluents from both
of these treatment  processes then would be combined
with  other  acid/alkali  wastes  containing metals  for
physical/chemical treatment  and sludge dewatering. A
flow diagram of the typical treatment system is shown in
Figure 1.
                   Precipitation —». Flocculatlon —». Clarification
Fig. 1—Conventional Treatment Technology Flow Diagram.

  Shops that would decide to use CWT for one or more
waste streams would need to install enough storage tanks
to  accommodate  the  various  wastes  separately.
Therefore,  within  the  model, storage was costed as a
treatment technology.  It was assumed that the storage
capacity would be large enough to contain at least one
day's waste flow. The equipment considered in the cost of
storage were 5,000 gallon tanks ($6,000 per tank,  1978
prices).
  The analytical model was formulated to consider five
waste treatment alternatives (Figure 2) which involve on-
site treatment and/or hauling waste (via truck) to and
treating at a CTF.

* Recovery technologies are a viable alternative; however, they were not
 considered in this analysis.
                                                     119

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                      Table 6
            1982 Pretreatment Standards*
                       (mg/l)
                      Average of Daily Values for
                    30 Consecutive Monitoring Days
  Pollutant                 Shall Not Exceed

  CN (T)                        0.23
  Cu                           1.8
  Ni                            1.8
  Cr (T)                         2.5
  Zn                            1.8
  Pb                            0.3
  Cd                           0.5
  Total Metals                    5.0

  *These standards appeared in the Federal Register (Vol. 44,
  No. 175) on September 7, 1979. The standards have since
  been revised; however, the CWT analysis was performed
  before the changes were instituted and, therefore, are not
  reflected in this analysis.
  In Option 1, the shopdoesnot discharge contaminated
process waters to the  municipal  sewer system. The
concentrated rinse waters and batch dumps for all waste
streams are  hauled to  a central waste facility for
treatment. The sludge from waste treatment is dewatered
at the  CTF to approximately 20 percent solids and is
hauled to a landfill.
  Shops that select Option 2 would treat the cyanide and
acid/alkali waste streams in-house (CN destruction, pH
adjustment/precipitation)  and  send the dilute  waste
treatment  sludge (approximately 4 percent solids) and
raw chromium waste stream to a CTF. The CTF would
properly treat  the chromium waste stream, dewater the
sludge, and haul the solids to a landfill.
  Option  3 is similar  to  Option  2 except  that the
chromium and acid/alkali waste streams are treated in-
     Optlon 1
                                     Option 2
    Option 3
                    Option 5
house  and the cyanide waste  stream and sludge are
hauled to a CTF.
  In Option 4, the shop chooses to treat all waste streams
in-house and to send only the dilute sludge (4 percent) to
the CTF for dewatering.
  Under Option 5, the shop is not utilizing the CTF.
Instead,  all waste  treatment and sludge dewatering  is
done in-house.
  A summary  of  in-plant  processes that would  be
performed by individual companies under each option in
shown in Table 7.
Data Input and Computer Logic Flow
  The information needed to run the model includes:
  •  Locations of each company and CTF site that are
determined by using a grided map
  •  Volumes  (gallons/day)  and  pollutant
concentrations (mg/l) of the three waste streams (i.e.,
cyanide, chromium, and acid/alkali)
  •  Number of daily operating hours and days per year
for each shop
  •  Total number of rinses  for  each shop  and the
number of rinses with flow reduction installed and with a
potential for flow reduction.
  •  Local waste hauling costs  ($/mile/5000 gallons)
  •  Interest rates
  •  Expected return on investment for industry
  •  Cost indexes (wholesale price  index for chemicals,
operating cost index, and chemical engineering plant cost
index)
  •  Estimated lifetime of equipment
  •  Local electric  power costs
  •  Assumed days of operation per year of the CTF
                        Table 7
        In-Plant Processes for Each Waste Stream
                  Under Each Option
                        Stream
   Option*  Chromium Cyanide   Acid/Alkali Sludge
                                                                    5
                                                                    5
                                                                    1-3-5
                                                                    1-3-5
                                                                    1-2-4-5
                      5
                      2-3-5
                      5
                      2-3-5
                      2-3-4-5
5
3-5
3-5
3-5
3-4-5
   'Process 1 - Chrome reduction
    Process 2 - Cyanide oxidation
    Process 3 - Physical/chemical treatment
    Process 4 - Sludge dewatering
    process 5 - Storage
    Process 5 - Storage
 Fig. 2—Waste Treatment Alternatives
  The model proceeds in an iterative manner to converge
on a solution using the following logic flow. On the first
iteration, a CTF is sized assuming all wastes are sent to
the CTF. The  CTF is a maximum size after the first
iteration, and therefore the cost for using CWT is the
least  possible because of economics of scale. In  the
second iteration, the model selects the least-cost option
for each shop.  Since  the  least-cost option  for  some
companies may be to treat a portion  or all of their wastes
in-house, the size  of the CTF at the end of the second
iteration may have decreased. A decrease in size will
cause user fees to increase because of a loss in economics
of scale.  If after the second  iteration, there was a change
of 5 percent or less in the size of the  CTF, the model will
                                                     120

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assume convergence and will stop with that solution. It
the change was greater than 5 percent, the model would
continue iterations until it converges on a solution.

CASE STUDIES
  As discussed, five metropolitan areas were selected for
case studies. A preliminary analysis has been performed
for each area using the microcomputer model, and results
will be discussed in this paper. In an attempt to keep the
discussion  to  a manageable  size  but to  retain a
comprehensive  view of the study, a detailed analysis is
presented for  only  one  area  (Cleveland) and   the
remaining  areas are  treated  with  a  more  general
approach.

Cleveland Analysis
  Data  were  collected  from  various  sources   for
approximately 140 metal finishing shops in the Cleveland
metropolitan area. From available information, it was
concluded that  103 of these shops were not currently
meeting  1982 pretreatment standards. These 103 shops
were considered in the analysis. The current water use
statistics for these shops are summarized in Figure 3.
 Fig. 3—Distribution of Cleveland Water Use Flow Rates

   As shown in Figure 4, the majority of the 103 shops are
 clustered in a 50-square-mile area, and approximately 15
 shops are located to the northeast in a second cluster. The
 potential CTF site is located in the southeast sector of the
 larger cluster. The mean distance between all shops and
 the potential CTF site is 7.8 miles. The nearest potential
 customer is located 0.5 miles from the central site, and the
 farthest  company is located 29.9 miles from the site. A
 summary of  major input parameters  is provided  in
 Appendix A.
   The   most   economical  waste  treatment  scheme
 determined  by  the  analysis  considering  in-plant
 treatment and CWT  is shown in Table 8. The annual
Fig. 4—Metal Finishing Shops In Cleveland Area.

costs associated with this configuration are presented in
Table 9. The necessary processing capacities of the CTF
components are shown in Table  10.
  The Cleveland results show a very high percentage ot
participation in the CWT system.  Only  one of the 103
shops has not selected to use the CTF. That particular
shop is located 19.5 miles from the CTF site and has a
waste stream flow of 43,200 gpd  after flow reduction.
   For the vast majority of the small (less than 10,000 gpd
before  flow reduction)  and medium  shops  (10,000 to
50,000 gpd before flow reduction)  the program selected
Option 1 (i.e., sending all wastes to the CTF) regardless of
distance  from the central  facility. The distance was,
however, a factor regarding the degree of flow reduction
used. In general, as the distance increased from the
central facility to the shops, the shops were more likely to
install counter-current rinses. The average distance to the
                       Table 8
      Most Economical Waste Treatment Scheme
                For Cleveland Region
  Option
Number of Shops
  1 - All waste to CTF
  2 - Chrome waste and all sludge to CTF
  3 - Cyanide waste and all sludge to CTF
  4 - Sludge only to CTF
  5 - Nothing to CTF
              86
               1
               0
              15
               1
Table 9
Regional Summary - Cleveland
(Annual Costs in Thousands of 1980 Dollars)




W/o CTF
With CTF
Savings

Total
Plant
Investment
1,926
345
1,581
Total
Plant
Operating
Costs
1,745
297
1,448
Total
Plant
Chemical
Costs
528
247
281

Total
Plant
Costs
4,199
899
3,310

Total
Transport
Costs
0
1,129
-1,129

Total
CTF
Fees
0
486
-486

Total
Regional
Costs
4,199
2,504
1,695
                                                     121

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Table 10
Processing Capacities and Costs of CTF Components
(All Costs in 1980 Dollars)
Process
Chromium
Reduction
Cyanide
Oxidation
Precipitation
Sludge
Dewatering
Storage
Required
Capacity
GPD
40,700
41,000
190,000
3,646
190,100
Annual
Investment
$ (1980)
7,200
17,800
36,100
19,000
58,200
Annual
Operating
Cost
$ (1980)
3,800
6,100
15,600
6,500
0
Annual
Chemical
Costs
$ (1980)
11,400
240,600
64,300
0
0
Total
Annual Costs
$ (1980)
22,400
264,500
116,000
25,500
58,200
Fee Rate
$/Gal
0.0018
0.0215
0.0020
0.0233
0.001
CTF for shops that decided to add counter-current rinses
on all single overflow rinses (with potential for counter-
current) was 9.3 miles. The average distance for shops
that decided  not to  install  counter-current  for all
potential rinses was 3.7 miles.
  For better  understanding of the  analysis and the
interpretation of the results, it will be most profitable to
look at two typical plants (Fl and E6) in detail. Fl  is an
electroplating shop that works mostly with electric switch
and outlet boxes. Aside from electroplating, the  shop
also performs degreasing/cleaning,  pickling, and bright
dipping. The shop has a combined waste flow of 18,500
gpd. It operates 11 hours per day for 250 days per year.
The shop  is located 6 miles from the CTF site.
  Fl  has  no  pretreatment  equipment.  The   final
wastewater discharge analysis (Table 11) indicates a need
for cyanide oxidation and heavy metal precipitation.
  Currently, Fl has a good housekeeping program. It
has installed flow control valves (5 gpm) on all seven of its
overflow  rinses.  Fl presently has  no counter-current
rinses, but all rinses have that potential. If waste streams
(Cr, CN,  and acid/alkali) were segregated into discrete
flows, the individual discharges following countercurrent
rinse installation  for Fl would be:
  Cr waste stream
  CN waste stream
  Acid/alkali waste stream
   0
7380
9225
                      Table 11
          Analysis of Final Effluent - Shop Fl
  Flow                                     18,500 gpd
  Cr (+6)                                   < 0.1 mg/l
  Cr (total)                                   0.3 mg/l
  Zn                                        53.5 mg/l
  CN                                       12.2 mg/l
  Fe                                         6.8 mg/l
  As a part of the total  analysis for Cleveland, the
computer program selected Option 1 (send all  waste
streams to CTF) as the least cost alternative for Shop Fl.
Also, the results  indicated that counter-current  rinses
should be installed at all rinse stations.
  The costs for Options  1 and 5 show a comparison of
CTF and  in-plant  processing  (Table  12).  For  this
particular shop, the option of sending its waste to a CTF
as opposed to in-plant treatment would save $43,900
annually.
  For large metal finishing facilities (greater than 75,000
gpd),  the  most  common   selection  of   treatment
alternatives was Option 4 (treating all waste  streams in-
house and sending dilute sludge to CTF for dewatering).
An example of the results for a typical large facility are
presented.
  Shop E6 works with automotive parts, appliances, and
industrial parts, such as fasteners and stampings.  Aside
from electroplating, process water uses include pickling,
cleaning, surface neutralizing, chromating, phosphating,
bright dipping and chemical polishing,  and stripping.
The current  process  wastewater  discharge  for  E6 is
225,000 gpd. The shop operates 24 hours per day and 340
days per year. The shop is located 8.5 miles from the CTF
site.
  E6 has 35 rinse stations, all of which have flow control
valves and approximately half of which  have counter-
current  rinsing. Rinse stations without counter-current
rinsing have no potential for installing counter current.
  This shop currently has no pretreatment. The effluent
analysis (Table 13) indicates a need for chrome reduction
(assuming hexavalent chrome exists), cyanide oxidation,
and  heavy  metal precipitation.
  The computer results show that the use of a CTF for all
waste streams (Option 1) would be the most expensive
alternative (Table 14). The least cost alternative is Option
W/o CWT (5)
With CWT (1)*
Savings
Investment
41,200
0
41,200
Costs for
(All
Operating
Costs
17,300
0
17,300
Table 12
Shop Fl Considering Options 1
Costs in 1980 Dollars Per Year)
Total
Chemical In-Plant
Costs Costs
2,600 61,100
0 0
2,600 61,100
and 5
Transport
Costs
0
14,000
-$14,000
. CTF
Fees
0
3,200
-3,200
Total
Costs
61,100
17,200
43,900
"Annualized storage and countercurrent investment costs have been included in transportation costs.
                                                     122

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4. With this alternative, E6 would be reducing its original
waste stream flow (225,000 gpd) by treating in-house and
by  sending only a  dilute sludge  to  the CTF for
dewatering.
                      Table 13
         Analysis of Final Effluent - Shop E6
 Flow
 Chrome (total)
 Zinc
 Cadmium
 Iron
 Cyanide
225,000 gpd
   8.5 mg/l
  21.8mg/l
  53.7 mg/l
  15.8 mg/l
  15.5 mg/l
Cleveland Analysis with Multiple CTF Sites
  A two-site CWT  case study was performed  to
investigate the  economic effects  of simultaneously
reducing the costs of transportation and the benefits of
economies of scale.
  The  study used the CTF  site (CTF Site 1) of the
original analysis and a second site (CTF Site 2), which is
located 4.2 miles southeast of Site  1. Metal finishing
shops were given the same five options as were available
in the  original analysis, where each shop could use the
facility closest to its location or treat on-site — 47 shops
were closest to CTF Site 1, and 56 shops were closest to
CTF Site 2. Because of the use of two central treatment.
Table 14
Costs for Shop E6 Considering Options 1
(All Costs in 1980 Dollars)



Option 1*
Option 4
Option 5
Savings
(4 vs. 5)


Investment
0
48,000
57,400

9,400

Operating
Costs
0
25,400
27,900

2,500

Chemical
Costs
0
50,400
50,400

0
Total
In-Plant
Costs
0
123,800
135,700

11,900
, 4, and 5

Transport
Costs
330,359
3,500
0

-3,500


C7T
Fees
60,890
1,800
0

-1,800


Total
Costs
391,250
129,100
135,700

6,600
'Annualized storage and countercurrent investment costs have been included in transportation costs.
                       Table 15
       Most Economical Waste Treatment Scheme
       for Cleveland Region Using Two CTF Sites
                             Number of Shops
   Option               Original Case  2-Site Case
1 - All waste to CTF
2 - Chrome waste and all
sludge to CTF
3 - Cyanide waste and all
sludge to CTF
4- Sludge only to CTF
5- Nothing to CTF
86

1

0
15
1
88

1

2
11
1
                 facility sites, the average distance of a shop to a CTF was
                 reduced  from 7.8 miles in the original analysis to 6.5
                 miles.
                   The most economical regional waste treatment scheme
                 (combining CTF Sites 1 and 2) is shown in Table 15. The
                 annual costs  associated  with this  configuration  are
                 presented in Table 16. The CWT system configuration
                 changed very little from the original single-site analysis.
                 The major change which occurred concerned four large
                 shops which originally selected Option 4 (sludge only to
                 CTF) now chose to  send some or all of  their raw
                 wastewaters to  the  central facility. As  expected,  the
                 distance to the CTF was reduced for each of these four
                 shops (Table 17).
Table 16
Regional Summary - Cleveland Using Two CTF Sites
(Annual Costs in Thousands of 1980 Dollars)




W/o CTF
With CTF
Savings

Total
Plant
Investment
1,926
298
1,628
Total
Plant
Operating
Costs
1,744
246
1,498
Total
Plant
Chemical
Costs
527
199
328

Total
Plant
Costs
4,197
743
3,454

Total
Transport
Costs
0
1,118
-1,118

Total
CTF
Fees
0
525
-525

Total
Regional
Costs
4,197
2,386
1,811


Shop Code
P4
N8
E5
E6
Option 4

M/7es to CTF
4.3
4.0
3.9
8.5
Table 17
Shops Affected in Two-Site
1-Site Analysis
Option Selected
4
4
4
4
Analysis

Miles to CTF
2.4
0.7
2.9
4.4

2-S/fe Analysis
Option Selected
3
1
1
3
                                                    123

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   The total annual savings for the Cleveland  Region
under the two-site analysis increased slightly ($48,000)
from the original analysis. This indicates that the loss of
some economies of scale  were less  than the savings in
reduced transportation costs.

Milwaukee Analysis
   Data  were  collected  for  approximately  60 metal
finishing shops in the Milwaukee metropolitan area. The
data shows that 41 of these shops were not meeting 1982
pretreatment standards and, thus, were included in the
CWT analysis.
Fig. 5—Metal Finishing Shops in the Milwaukee Area
                      Table 18
      Most Economical Waste Treatment Scheme
                For Milwaukee Region
  Option

  1 - All waste to CTF
  2 - Chrome waste and all sludge to CTF
  3- Cyanide waste and all sludge to CTF
  4- Sludge only to CTF
  5 - Nothing to CTF
Number of Shops

       23
       3
       2
       13
       0
Fig. 6—Distribution of Milwaukee Water Use Flow Rates.


   Figure 5 shows the location of the 41  metal finising
shops.  Most of the shops are located in  a 4-mile wide
vertical strip along the eastern shore of Lake Michigan.
The  potential CTF site is located at approximately the
center  of this eastern  strip. The other metal finishing
shops  are dispersed over a 100-square-mile area. The
mean distance between all shops and the potential CTF
site  is  7.8 miles. The nearest and farthest shops are
located 0.1 and 30.2 miles, respectively, from the CTF
site.  The distribution of water use flow rates for the 41
shops is shown in Figure 6.
   The  most economical waste treatment scheme is shown
in Table  18. The  annual costs  associated with  this
configuration are presented in Table 19.
   The  results from the  Milwaukee  analysis show the
effect of having a high percentage of medium and large
shops.  For Milwaukee, only 40 percent of the shops use
25,000 GPD or less of water, and 48 percent use greater
than 50,000 GPD. In Cleveland, the  percentage was 60
percent for less  than 25,000 GPD and 27  percent for
greater than 50,000 GPD. The effect is that 32 percent of
the Milwaukee shops have selected Option 4 (send only
sludge  to CTF) as the most economical waste treatment
alternative;  whereas  in  Cleveland,  only  14  percent
selected that option.


Philadelphia Analysis
   Data were collected  for approximately 90  metal
finishing shops in the  Philadelphia metropolitan area.
Fifty-one  of  these  shops  were  not  meeting  1982
pretreatment standards and  were used  in the  CWT
analysis.
Table 19
Regional Summary - Milwaukee
(Annual Costs in Thousands of 1980 Dollars)



w/o CTF
With CTF
Savings

Total
Plant
Investment
898
432-
466
Total
Plant
Operating
Costs
710
323
387
Total
Plant
Chemical
Costs
249
220
29

Total
Plant
Costs
1,857
975
882

Total
Transport
Costs
0
342
-342

Total
CTF
Fees
0
120
-120

Total
Regional
Costs
1,857
1,437
420
                                                    124

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     Philadelphia Area
Fig. 7—Metal Finishing Shops in the Philadelphia Area.
  Figure 7 shows the location of the 51 metal finishing
shops. A major portion of this metal finishing population
is located in  southeastern Philadelphia,  in an  area
bordered  by the Schuylkill and Delaware Rivers. The
potential CTF site is located in the extreme southeastern
corner  of  Philadelphia near  the  Philadelphia
International Airport. The mean distance  between the
shops used in the analysis and the potential CTF site is
10.1 miles. The nearest potential customer is located 2.4
miles from the  central site, and the farthest company is
located 26.7 miles from the site. The distribution of water
usage rates for the 51 shops used in the analysis is shown
in  Figure  8.  The  most economical waste  treatment
scheme is shown in Table 20. The annual costs associated
with this configuration are presented in Table 21.
  The results of the Philadelphia analysis show a strong
resemblance to the Milwaukee results. A large percentage
(39 percent) of the Philadelphia shops selected Option 4.
Again, this is primarily a result of having a relatively high
percentage of medium and large water users (51 percent
of shops in Philadelphia use  more than 50,000 gpd).
  Philadelphia  also showed a relatively high percentage
of shops  selecting Options 2  and  3 (18 percent as
                                                                                                  2%      2%
Fig. 8—Distribution of Philadelphia Waster Use Flow Rates
compared to 1 percent for Cleveland and 12 percent for
Milwaukee). This is primarily  a result  of  having a
relatively larger mean distance from the shops to the CTF
site.  The average CTF distance of the nine Philadelphia
shops selecting Options 2 or 3 was 10.0 miles. This caused
some waste  streams (usually acid/alkali) to be  cost
effectively treated in-house and for other streams (usually
chrome) to be hauled and treated at the CTF.

Atlanta Analysis
  Data were collected for 54 metal finishing shops in the
Atlanta metropolitan area.  The available information
indicated that 23 of these shops were not meeting 1982
pretreatment standards and were, thus, considered in the
CWT analysis.
  Most of  the  23 metal  finishing shops used in  the
analysis are well distributed in  a 20-square-mile area
which is centered over downtown Atlanta (Figure 9). The
potential central facility site is located 5  miles southeast
of the center of the city. The mean distance between the
shops and  the potential CTF site is 5.6 miles. The nearest
and  farthest shops  are located  2.2  and  11.6  miles,
respectively,  from  the  potential  CTF  site.   The
distribution of water use flow rates is shown in Figure 10.
  The   most  economical   waste  treatment scheme
                      Table 20
      Most Economical Waste Treatment Scheme
                for Philadelphia Region
  Option

  1 - All waste to CTF
  2 - Chrome waste and all sludge to CTF
  3 - Cyanide waste and all sludge to CTF
  4 - Sludge only to CTF
  5- Nothing to CTF
Number of Shops

       22
       8
       1
       20
       0
Table 21
Regional Summary - Philadelphia
(Annual Costs in Thousands of 1980 Dollars)




W/o CTF
With CTF
Savings
Total
Plant
Investment

1,189
661
528
Total
Plant
Operating
Costs
961
560
401
Total
Plant
Chemical
Costs
1,020
995
25

Total
Plant
Costs
3,170
2,216
954

Total
Transport
Costs
0
478
-478

Total
CTF
Fees
0
84
-84

Total
Regional
Costs
3,170
2,778
392
                                                    125

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 considering in-plant treatment and  CWT is shown in
 Table  22.  The  annual  costs  associated  with  this
 configuration are presented in Table 23.
                       Table 22
       Most Economical Waste Treatment Scheme
                  for Atlanta Region
   Option                           Number of Shops
   1 - All waste to CTF                        19
   2 - Chrome waste and all sludge to CTF       0
   3 - Cyanide waste and all sludge to CTF       0
   4 - Sludge only to CTF                     4
   5 - Nothing to CTF                         0
                        The Atlanta results  show a  relatively good CWT
                      system participation. This high CWT is primarily a result
                      of the closeness of the  shops to the central treatment
                      facility site (mean distance 5.6 miles). The four Option 4
                      shops in the analysis are large shops (greater than 50,000
                      gpd) most of which are located 10 or more miles from the
                      CTF site.

                      Seattle Analysis
                        Data were  collected for  approximately 60 metal
                      finishing shops in the Seattle metropolitan area. The data
                      showed that 22 of these shops  were not meeting 1982
                      pretreatment standards  and were thus, included in the
                      CWT analysis.
Table 23
Regional Summary - Atlanta
(Annual Costs in Thousands of 1980 Dollars)

W/o CTF
With CTF
Savings
Total
Plant
Investment
404
80
324
Total
Plant
Operating
Costs
341
61
280
Total
Plant
Chemical
Costs
81
51
30
Total
Plant
Costs
826
192
634
Total
Transport
Costs
0
217
-217
Total
CTF
Fees
0
92
-92
Total
Regional
Costs
826
501
325
                                  Atlanta Area
Fig. 9—Metal Finishing Shops in the Atlanta Area.
                      Table 24
      Most Economical Waste Treatment Scheme
                  for Seattle Region
  Option

  1 - All waste to CTF
  2 - Chrome waste and all sludge to CTF
  3 - Cyanide waste and all sludge to CTF
  4 - Sludge only to CTF
  5 - Nothing to CTF
Number of Shops

       11
       0
       0
       11
       0
Fig. 10—Distribution of Atlanta Water Use Flow Rates

   Figure 11 shows the location of the 22 metal finishing
shops  of concern. The majority of the shops are located
between Puget Sound  and  Lake  Washington.  The
remainder  of the shops are  located in the northern
portion of  King County and in the Kent area.  The
potential CTF site is located near the southern two shops
in Kent. The mean distance between the shops and the
potential CTF site is  16.6 miles. The nearest and farthest
shops  are located 2.1  and 33.2 miles, respectively, from
the CTF. The distribution of water use flow rates  is
shown in Figure 12.
  The  most economical waste treatment scheme is shown
in Table  24.  The annual  costs  associated with  this
configuration are presented in  Table  25.
  For  Seattle, the  greatest factor  was  the  hauling
distance. Although 76 percent of the  metal finsihing
population considered in the analysis used less than 50,00
gpd of water, only half of the total number of shops sent
raw waste streams to  the CTF. The mean distance to the
CTF for the plants selecting Option 4 was 19.5 miles. For
the remainder of the shops, the mean CTF distance  was
12.8 miles.
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Table 25
Regional Summary - Seattle
(Annual Costs in Thousands of 1980 Dollars)



W/o CTF
With CTF
Savings

Total
Plant
Investment
367
156
211
Total
Plant
Operating
Costs
319
133
186
Total
Plant
Chemical
Costs
22
17
5

Total
Plant
Costs
708
306
402

Total
Transport
Costs
0
154
-154

Total
CTF
Fees
0
65
-65

Total
Regional
Costs
708
525
183
Fig. 11—Metal Finishing Shops In the Seattle Area.
 PHASE II CWT SYSTEM DESIGN
   Phase I of this project investigated the feasibility of
 CWT  and  defined  the conditions  necessary for its
 successful implementation.  The second phase is directed
 at developing and demonstrating procedures for creating
 CWT systems.  This  is being achieved by selecting one
 area for detailed study to develop a comprehensive metal
 finishing waste control plan for that area. The process for
 selecting the Phase  II area and  an overview of  the
 subsequent  study and  analysis are presented in  the
 following paragraphs.

 Selection of Phase II Study Area
  The Phase II area was chosen as the most feasible site
for central waste treatment from a technical, economical,
political, and administrative standpoint. The  selection
procedure utilized by the project team  to identify  the
most feasible area had two  basic steps:
                                                          Fig. 12—Distribution of Seattle Water Use Flow Rates.
   • Screening Exercise
   • Assessment of Economic Feasibility
   The objective of the screening exercise was to provide a
 quantitative and rational means of selecting from the 24
 metropolitan  areas studied in Phase I, the most likely
 candidate  areas  for the  Phase II  centralized  waste
 treatment  study. The procedure that was utilized was
 similar to the  selection process used in Phase I to choose
 the five case study areas, the basic decision tool being the
 worth assessment model.
   The criteria used in the Phase  I  worth assessment
 exercise   were  expanded  to  satisfy additional
 requirements  of Phase II.  First, an area to be selected
 should have available from local authorities water use
 and industrial discharge data that characterizes its metal
 finishing population. This information would be needed"
 for the subsequent  modeling to determine  economic
 feasibility.  Secondly, it was determined that it would be
 advantageous  from a project administrative standpoint if
 the municipal contact for the  project was  in  a high
 visibility position with broad authority. In some cities,
 the contact's  authority was limited  to the  municipal
 wastewater system. In these cases,  it was difficult  to
 obtain information on solid waste disposal sites and on
 other data requirements related to economics or land
 availability.
   In  other cities, contacts  included  environmental
 directors that  had an overview of both wastewater and
 solid  waste control,   economic  development
 administrators that were aware of the availability of land
 for potential CTF sites, or personnel from the mayors'
 offices that had a comprehensive view of all information
needed  during this  project. These various  levels  of
contacts were  weighed as to their ability to supply the
appropriate project information and generally contribute
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Table 26
Results from Sensitivity Analysis -
Location
Cleveland
Seattle
Philadelphia
Tulsa
Atlanta
Buffalo
Erie
Chicago
Trenton
Dallas/Ft. Worth
San Francisco
Boston
Alburquerque
Canton
Cincinnati
Denver
Houston
Miami
Milwaukee
Rochester
San Jose

Case 2
Value
0.78
0.71
0.68
0.66
0.63
0.6
0.6
0.56
0.51
0.46
0.4
0.37
1
0
0
0
0
0
0
0
0
to the project. After inclusion of the additional criteria,
the worth assessment model was utilized.
  The results from the exercise  are shown in Table 26.
From these results,  it is evident that the metropolitan
areas of Seattle and Cleveland best satisfy the Phase II
criteria. These metropolitan areas were considered in the
second step of the Phase II selection procedure.

Assessment of Economic Feasibility
  To perform  the economic assessment, a  simplified
version of the Phase I analytical model was developed
and applied to metropolitan areas with the highest worth
assessment  scores.1  The  project  plan  first was  to
determine the economic feasibility of CWT in Seattle and
Cleveland. Then,  if neither area appeared promising,
other cities, starting with Philadelphia, would be added
to the analysis.
  From the modeling exercise, it was concluded that the
Cleveland metropolitan area presented more favorable
economic  conditions   for   CWT  implementation;
therefore, Cleveland was selected as the study area for the
Phase II portion of the project.

DATA COLLECTION AND  ANALYSIS
  The Phase II analysis was to be more  in-depth and
comprehensive than the case studies of Phase I.  A new
and more sophisticated tool was developed for providing
additional  treatment options, such as  in-plant waste
stream concentration using ion exchange.
  The data requirements of Phase II demanded that the
information base  collected via  the industry  survey be
expanded.  This  was accomplished through   on-site
engineering surveys at the major metal finishing shops in
the study area. Surveys of 66 companies were conducted
during % 6-week period in early  1980 for data collection
purposes.
'Phase II of the CWT project was started several months before all the
 data and results of Phase I were.available. This overlapping of project
 phases was done in response to the urgency to demonstrate CWT
 before metal finishing  companies  were committed to in-house
 treatment for meeting pretreatment standards; therefore, a simplified
 model was developed to determine relative feasibility.
  The on-site surveys consisted of discussions with plant
personnel, a tour of the plating facility, and waste stream
sampling. For each  shop, a schematic diagram of the
plating  lines was drawn to illustrate the sequence of
manufacturing processes showing rinse water flow rates
and indicating which baths were batch dumped and the
frequency of their discharge. Also, for each rinse tank, it
was  noted if flow reduction measures such as still or
counter-current  rinsing, flow  control  valves, spray
rinsing or recovery technology, were in place, or could be
added.
  Sampling of the final discharge  was performed at
shops for which municipal data did not  exist.  Also,
individual samples, such as rinses following cyanide or
chrome-containing  baths, were  taken from particular
waste streams to establish parameters that would be used
in the analysis.
  The new  analytical tool  that  was developed for the
Phase II analysis was an optimization model. The model
is a mixed-integer, linear-program algorithm that has a
function similar to the micro computer model used for
the case study analysis. The new model, like its simplified
predecessor, determines  the  least  cost regional waste
treatment scheme  considering in-plant treatment and
CWT for typical wastes generated  by metal  finishing
companies.
  The optimization model contained several important
advantages over the micromodel. First, included in the
new  model was an additional in-plant technology, ion-
exchange. Shops were given the option of using  ion
exchange units with applicable plating  baths.  It was
assumed the units  would  be installed on  still rinses
following plating tanks and used to concentrate the waste
stream  for  shipment to a  central  treatment facility.
Concentrating techniques are available for other plating
methods.
  Another advantage of the optimization  model is its
ability to consider the choice of multiple CWT sites (the
micromodel was limited to one  potential CTF site per
analysis).  This option  should  be considered  when a
regional area is planning CWT so that volume reductions
can be facilitated. Several central waste treatment plants
may  significantly  reduce transportation costs.  Each
treatment facility could contain treatment for  all waste
streams  and provide  sludge dewatexing,  or certain
facilities could specialize by treating only certain waste
streams  or  be limited to  wastewater  treatment and
transport  dilute  sludges  to  another facility  for
dewatering.  The model simulates the most economical
combination of treatment sites considering all possible
permutations.
  The utilization of the Phase II model began last month.
The analysis is not yet complete,  but preliminary results
show a  close similarity to the Phase I results.
  A  report describing the  Phase  II  analysis  and
presenting results of the study will be completed in June
1980. Also, a 1-day seminar will be held in Cleveland to
discuss  the results  with the  local plating  industry
representatives  who have participated in the  Phase II
study.


MANAGEMENT AND FINANCING OPTIONS
Introduction
  Much  of the  evaluation process  for  choosing  a
particular approach must be subjective and is dependent
on  an  assessment  of local  requirements.  Ideally,  an
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 objective  evaluation  of  these  options  should  be
 undertaken by industrial representatives and cognizant
 officials including state or local economic development
 officials,  municipal  sewer  agency  officials  and
 representatives  from the local banking or investment
 community.  Suitable relations with the media and local
 environmentalists will aid in providing an open dialogue
 on the purpose of the facility, its backers, and future
 siting  attempts.  The   following  sections  provide
 information  on the general approaches to  these,

 MANAGEMENT OWNERSHIP OPTIONS
   Overview—Management and ownership options fall
 into three basic categories: private, public, or cooperative
 ownership. Private ownership would  be by firms that
 specialize in  waste treatment and disposal, although it is
 possible that a single electroplater could build a CTF to
 handle his and other platers'  waste. Public ownership
 could be by state, county, municipal, or  quasigovern-
 mental  economic  development  corporation.   Finally,
 cooperative ownership implies either a joint venture or a
 general-limited partnership of CTF users.
   In addition to full private and full  governmental
 electroplater  cooperative  ownership, there  are  two
 scenarios that  represent  variants to the  basic
 management options. These include:
   • Government or electroplater ownership of the land
 with an outside firm owning and operating the CTF
   • Governmental or industry ownership of the land,
 buildings, and  equipment used  in the CTF  with an
 outside firm being hired to manage the facility
                      Table 27
       Possible Management Ownership Options*
  Complete
  Private
  Ownership
           1.  Complete ownership, financing and
           management responsibility by an outside firm.

           2. Complete ownership, and management
           responsibility by an outside firm with financing
           assistance (i.e., loan guarantees, loans, or non-
           recourse financial investments) by state/local
           government and/or an industry user group.
           3. Ownership, financing and management
           responsibility by an outside firm of a CTF built
           on government-owned or industry-owned land.
           4. Ownership and management responsibility
           by an outside firm of a CTF built on
           government-owned or industry-owned land
           state/local government and/or industry
           financing assistance.
           5. State/local government and/or industry user
           group ownership and financing of a CTF which
           is managed under contract by an outside firm.
Government  6. Complete state/local government and/or
and/or Industry industry user group ownership, financing and
User Group   management responsibility.
Ownership
  In Table 27, these three options are distributed into six
management scenarios. While these scenarios are not the
universe of all possible choices, they are presented as a
representative cross-section and should be modified for
local conditions.
  The selection process will be influenced in large part by
the following factors:
  • The   level of  management  control  desired  by
government and/or industry user groups
  • The   willingness  and  capability  of government
and/or industry user groups to participate in financing
                                                          • The  level  of liability for CTF operations that
                                                        government and/or industry user groups are willing to
                                                        accept
                                                          Management control over the pricing of services and
                                                        the user access to a CTF will, of necessity, be determined
                                                        by the risk associated with the  potential dangers of
                                                        handling  and disposing  of hazardous materials. As
                                                        shown  in Figure 13, if the potential  customers and/or
                                                        local government are concerned that the CTF should
                                                        service small business and provide the treatment services
                                                        at a below market user fee, then the potential customers
                                                        and/or local governmen. will need to be willing  to
                                                        assume a role in the financing  package and assume the
                                                        degrees of risk associated with  this participation. If the
                                                        potential  customers want  to transfer all of the risks,
                                                        financing considerations and management problems to a
                                                        third party, they also must delegrate management control
                                                        and pricing authority.
  Management/Ownership Options:
  1. Complete ownership by outside private firm.
  2. Complete ownership/management by outside firm
     with financing assistance by state/local government
     and/or industry user group.
  3. Ownership.management of CTF by outside firm.
     Land owned by government or industry user group.
  4. Combination of Options 2 and 3.
  5. Ownership  by  state/local  government  and/or
     industry  user group. Contract management  by
     outside firm.
  6. Ownership/management by state/local government
     and/or industry user group.
Fig.  13—Financing  Participation,  Control,  Liabilities  and
Management/Ownership Options.

Private Ownership
   Private ownership delegates complete management
control  of  operating  liabilities  and  financing
responsibilities to a private firm providing a service
similar  to chemical  suppliers.  While it  prevents local
government  and  industry  from  exercising extensive
control over customer selection or user fees, it requires no
capital  outlay  for  facilties  by  electroplaters.  The
responsibility  of  compliance  with  appropriate
wastewater  treatment  and  solid  waste  regulations is
delegated to a responsible private concern.

Private Ownership Using Public Financing Assistance
  The economics of  scale are the primary attraction of
centralized waste  treatment facilities, though  market
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competition by competing private centralized treatment
facilities will ensure  that small business customers are
likewise serviced and that reasonable user fees are
charged. Many potential treatment firms are limited by
their  access  to  investment  capital; therefore,  local
government can assist in providing traditional financing
assistance through  loan guarantees, direct loans,  or
equity investments.

Private  Ownership  Using   Government Land—
Attracting private capital int&this^reatment business can
be assisted by providing suitable government owned land
at reduced  or token  lease  prices. Since these treatment
facilities must be in industrialized areas near the plating
community, higher land cost may raise the user fees for
potential  users.  However,  if the   local  government
provides suitable land at a reduced price, the attraction to
private firms will increase.

Private Ownership in Management with Public Financial
Assistance  in Land  Aquisition. A  hybrid  of the two
previous  sections combining  financial assistance and
land dedication could provide the maximum incentive
for private concerns  to enter the business and provide
local participation in  managerial control. For example, if
a consortium of industry users purchased and dedicated a
track of  land or contributed  capital to the facility, it
would be  in a position  to  negotiate for long-term
contracts and certain liability surety.

Government  or Cooperative  Ownership with Contact
Management] The Federal Government  owns  several
nuclear reactors that  are operated on a contract basis by
private firms. Similarly, a centralized facility owned by
an  industry  cooperative  and operated  by contract
management  can be conceived. Cooperatives similar to
those used for gain and other farm commodities could be
capitalized  by the electroplating industry and managed
by a contractor.

Government  or Electroplater  Cooperative  Ownership.
This approach is similar to the one described previously
except that control  over the design, construction, and
operational  management  of a centralized facility is
maintained by the government or industry consortium.
Management by some form  of Board of Trustees or
general partner (as in a limited partnership) would place
operational responsibility with the partner.

Financing Options
   Overview.  The options available to capitalize central
facilities  are  numerous  and include traditional private
source bank loans or corporate bond issues as well as
Federal and state programs designed to assist businesses.
Hybrids and combination of these financing approaches
can be considered and tailored to available programs and
local needs.  The success of a potential package will
require resourcefulness and creativity in developing and
financing plans responsive to individual situations.

   Conventional Loans. Conventional loans are available
from lending institutions to finance projects of this type,
assuming  existing  corporate  financial  strength  is
supported  by  well  established ties  with the financial
community.  The current credit  markets dictate loan
availability and credit rate.

   Debentures.  Private investment funds raised by issuing
debentures   are  direct   obligations  of   the  issuing
corporation dependent entirely upon its general credit
rating, reputation, and prestige. These are normally used
by large, financially successful companies as a means of
raising capital through debt financing. Minimum dollar
requirements are required to justify the underwriting
costs.

  Small Business Investment Corporations. The Small
Business Investment Act of 1958 authorized the creation
of Small Business  Investment Corporations (SBIC) to
provide long-term capital to small businesses. Approval
by the SBA, which licenses SBICs, is required if the SBIC
wishes to invest more than 20 percent or $500,000 in a
single small business concern. SBICs may be unable to
solely underwrite a capitalization of this type; however,
they may play a role in developing an overall financing
package.

  Industrial Development Bonds. Tax exempt industrial
development  bonds  can be  issued by state or local
government for financing industrial development. IDBs
issued  for  pollution control financing do not  have a
dollar  limitation; however,  using this mechanism to
promote industrial pollution projects  with tax exempt
status  requires  strict  adherence  to   state  and IRS
regulations. Until recently, few small firms were able to
utilize this source of capital because investment bankers
required minimal credit risks and guaranteed repayment
for financing this  debt on  nonproductive  pollution
control facilities.

   Small Business Administration Guarantees. In 1976,
Congress authorized SBA to guarantee 100 percent of a
small business's obligation to finance a pollution control
facility. PL-94-305 assures that smaller firms can obtain
favorable financing rates and terms similar to those of
major corporations. Guarantees of this type are to be
used by credit worthy businesses and no credit denial by a
bank is required.  Section  8  of the Federal  Water
Pollution  Control  Act  and  PL-94-305  provide  the
following programs to small businesses:

   SBA Pollution Control Revenue Bond Guarantees
   SBA Loan Guarantee
   SBA Participation Loan
   SBA Direct Loan
   SBA Section 502 Programs

   Bond  guarantees  are  made to small viable credit
worthy companies  to provide low-interest, long-term
financing for pollution control needs. Firms must have
been in business for at least 5 years and profitable for at
least 3 of those 5 years.
   Loan guarantees  are provided for those businesses
unable  to  obtain conventional bank  loans and would
otherwise suffer substantial  economic injury to comply
with  Federal  treatment  regulations.  Some financial
positions  and  reasonable  repayment assurance  are
required, but provides advantageous interest rates.
   SBA also may participate in a  loan with a bank.
Normally, SBA's maximum participation is 75 percent of
the project cost; however, if a bank exceeds its lending
limit, SBA share may be raised an additional 15 percent.
Direct loans up to $500,000 are available for acquiring
pollution control equipment.
   SBA can  assist  local development companies  in
creating facilities for small businesses. Section 502 of the
Small Business Investment Act of  1958  allows  for
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loans for  facilities that small businesses may lease or
purchase.
  Economic Development Administration. The Federal
Government takes a major role in restoring economically
depressed areas through the Public Works and Economic
Development Act of 1965. Eligible programs in specially
designated areas are as follows:

• Direct grant for government owned projects
• Supplementary grants to augment other grants when
  applicants are unable to meet local government shares
• Loans in severely distressed areas for financing public
  works;  65  percent  for industrial  and commercial
  expansion; 90  percent for working capital and fixed
  assessed loans.

  Other  Federal  Programs.  The  Farmers  Home
Administration and  the Department of Housing and
Urban  Development  may  be  further  sources  of
information on Federal programs subsidizing projects
that are in the public interest. Municipal bonds and state
programs  should  be  likewise  investigated   when
considering a financing approach.
  Summary.  Financing and management of a central
facility may provide for its success or failure. Strong
considerations  should  be  given  to  the  specific
requirements of the user community, Federal, state, and
local governments, and the financing community. The
major requirement falls, however,  upon the potential
user community in  providing  a united front towards
creation of these facilities. Participation by the industry
developing this treatment capacity will help assure its
success.
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      Hazardous  Waste Management  Facilities:
     The  Siting  Problem  and  Possible Solutions
                                            Frank Boni*
INTRODUCTION
  Waste disposal from the surface finishing industry was
cited as one of the most serious problem areas in both of
the two previous AES/EPA Conferences. A year ago in
this meeting EPA's John Lehman (1) estimated that 90%
of all waste disposal facilities will not be environmentally
acceptable. That is,  they will not meet the prospective
RCRA requirements.
  The  problem regarding surface finishing wastes is
simply  this:  Landfill  capacity is  limited and surface
finishers may be unable to  find  safe, legal  disposal
facilities. And public opposition to  siting may delay the
development of additional disposal capacity.
  The problem is widely attributed to more stringent
environmental  standards  coupled with  public
apprehension  regarding  waste management  facilities,
particularly facilities sited or proposed for siting in "my
backyard."
  While it appears there is a role for state governments in
the solution of the problem, perhaps there is also a role
for the surface finishing industry and the AES, an
educational role.

Legislation and Regulations
  Waste disposal options have been the target  of much
legislation. Those disposal options are being increasingly
regulated to minimize their potential threat to the public.
  As a consequence of the Federal and State activities
there are substantial programs in place to enhance air and
surface water quality. But the  ultimate fate of  the
pollutants removed  from air  and  water has become a
major disposal problem.
  Ironically, the earlier statutes actually added to the
amount of hazardous  waste disposed  of on land. For
example, the Clean Water Act which affords cleaner
navigable waters  implies more land disposal for  the
removed  hazardous  materials.   Concern  over  this
problem led  the  Congress  to  pass the Resource
Conservation and Recovery Act (RCRA) in 1976. Of
particular importance to surface finishers is subtitle C of
RCRA which creates a "cradle-to-grave" control system
for the  management of hazardous wastes.
*Frank Boni
 Liqwacon Corporation
 Blue Bell, PA 19422
  The proposed RCRA regulations have been reviewed
(2) in recent months by the Subcommittee on Oversight
and Investigations of the U.S. House of Representatives.
That group made recommendations for improving the
Act and the regulations. The Subcommittee urged that
EPA promulgate those regulations at the earliest possible
date, noting that  their  promulgation  is  the key to
enforcement of RCRA. (Sections 3002, 3003  and 3010
applicable  to generators and transporters  were being
issued as this paper went to press.)


Public  Opposition
  In a letter (3) to the Electroplating Industry in regard to
the problems associated with production, treatment and
disposal of wastes, AES discussed the September 7, 1979
electroplating pretreatment standards and forthcoming
solid waste regulations. Executive Director Schumacher
wrote:
   "These  new regulations will require the metal
   finishing industry to improve its waste water and
   sludge treatment and disposal practices."
  There are several practices available for disposal of
sludges. Myron Browning and his associates  discussed
them in this meeting last year (4).  Methods included were
landfills, reclamation, chemical  fixation  and  heat
treatment.  They concluded  landfill disposal is still the
most common  practice in the plating industry and will
probably be so  as long as the recovery processes are not
economical.
  However, community acceptance of the establishment
and operation of new  landfill facilities (and continuing
operation of existing facilities) may prove to be the most
difficult aspect of the problem  associated with  those
landfills. The Comptroller General in his report to the
Congress (5) describes public opposition as the major
barrier to expanding disposal capacity:
   "Information obtained from  State  and industry
   officials, representatives  of environmental interest
   groups,  and environmental  impact  statements
   indicate that people are against the permitting of
   sites for many reasons.  For example, people are
   fearful of groundwater contamination, air and land
   pollution, fires, explosions, spills, rodent damage,
   odors, and dust dispersion. They complain that if a
   hazardous waste facility is built near them, the
   value of their homes will decline and future real
   estate development  will be inhibited. They protest
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   that they do not want their community to be known
   as a 'dumping ground' for other people's waste."

 Public Opposition: Coping With It
   Public opposition to the siting or expansion of landfills
 or even continuation of existing landfills takes different
 forms. The more visible opposition may be witnessed on
 the television screen as the news cameraman focuses on
 an obviously disturbed citizenry  carrying placards and
 blocking entrance to a landfill in  the community. A less
 dramatic, but perhaps more effective opposition, is the
 power held  by  many  municipalities  to  control
 development through zoning or other regulations.
   Increasingly it seems that it might be necessary for the
 state governments to become involved  in the  siting
 process if  reason  rather than emotion is  to  be
 determinant.  If state  involvement is  appropriate,  the
 questions that arise include:
        What is the preferred form of involvement by
        the state government in the siting process?
        How and  when should the public participate
        in the  siting  process  to best assure that
        facilities are safe?
   As for the form of state involvement, our view is that
 the private sector will provide the  necessary disposal
 facilities if the states create a regulatory framework. An
 opposite point of view is that private enterprise will  not
 be able to  meet the demand for legal disposal when the
 new  standards  become effective.  Accordingly,  such
 advocates reason that the government should  establish
 disposal facilities with operation  either by the State or
 contracted to  private industry.  With  regard to this
 controversy,  it is worth noting that there is no provision
 in  RCRA  for  any  Federal  support   for  facility
 construction  on the  Congressional premise  that  the
 private sector would  respond  if given  a regulatory
 program.
   There are already a few models for state involvement in
 the process of siting of landfills. However, because those
 models are so  new there  is very little experience to
 validate them. The 1979 Michigan "Hazardous Waste
 Management Act" (6) provides for a site approval board.
 That board will review and grant or deny final approval
 for  each  site  construction   permit  application
 recommended for approval by the State's environmental
 agency, the Department of Natural Resources  (DNR).
   New York's Industrial Hazardous Waste  Management
 Act  is  proposed to be amended  to  give facility siting
 boards the discretion to supersede local zoning in those
 cases where such zoning is considered unfair, arbitrary or
 generally not in keeping with the  overall public interest
 (7).
   At least  one trade group, the National Solid Wastes
 Management  Association  (NSWMA), has  formally
 expressed its  attitude regarding state involvement in the
 siting  process  (8). They  suggest the  states  provide
 mechanisms for overriding local zoning ordinances when
 necessary   and  that  incentives  be  paid  to  a  host
 municipality by  the users of a facility.
   The  three preceding concepts of state involvement in
 the siting  process  include  mechanisms  for public
 participation. Public participation in the Michigan siting
 protocol takes the form of representation on the 9-
member site approval board. That board which acts on
applications aproved by DNR includes four temporary
positions filled by residents of the minicipality and the
county in which the disposal facility is proposed to be
 located. Two of the permanent representatives are also
 public members, one is to be a geologist and the other a
 chemical engineer, both  of whom are from faculties  of
 Michigan's higher education institutions.
   In New York one of the options under consideration
 includes an independent agency or organization  to be
 created to  serve as  a mediator  and  to  negotiate
 agreements between citizens and the proposed developers
 of a hazardous waste facility.  New  York would ensure
 that the resulting agreements were made binding by the
 incorporation into the permits  and certificates which are
 required  before  the facility could  be constructed and
 operated.
   Mediation, as a negotiated  process for resolution  of
 public conflicts,  has  been successful  in some recent
 controversies (9). The  mediation  process  is  getting
 increasing attention. There is report (10) of a mediation/
 compensation  concept being  advocated  to the EPA.
 There are two central ideas in  the proposal:
    1. The  most effective way to deal with the social and
      political  issues  is community compensation
      through mediation, and
   2. Siting strategies must be adopted on the state  level.
      EPA's  role   would   be  to   promote   the
      compensation/mediation strategy  among the
      states.
   In their  position paper  NSWMA  also  provides  a
 mechanism for social appraisal of a site application that
 has  received favorable environmental review. NSWMA
 advocates establishment of a siting board whose makeup
 would be similar to that of Michigan.
   Donald Andres recently predicted  (II) the solution of
 this problem (public acceptance of proposed disposal
 sites) will be an emerging planning partnership between
 state governments and the waste producing/waste service
 industry.  At this writing  we are  working  hard  in
 Pennsylvania to develop such a  partnership by way of an
 Industrial  Advisory  Group  to the  Department  of
 Environmental Resources (DER). The Advisory Group
 consits largely of industrial waste generating companies.
 That group appointed a subcommittee from the waste
 service  industry  to  assist   them  in  the  siting
 recommendations they are creating for the DER. DER
 will  consider those recommendations in the legislation
 proposals they are developing for the  General Assembly.
 It is too early  to appraise the success  of this  new
 government/industry  partnership.

 Education: A Role for AES?
   In   all   the   preceding  ideas  for  resolving  the
 social/political issues through  public participation the
 assumption is  made  that  the public has  adequate
 awareness of the need for disposal facilities and is able to
 distinguish among the risks and benefits posed by the
 facilities.
   Yet such public awareness cannot be taken for granted.
 An educational effort  directed  at raising the level of
 understanding (not to be confused  with propaganda)
 needs to be undertaken. Perhaps EPA through its Office
 of Public Awareness can provide support for this effort,
 but it seems the effort is more likely  to be successful if
 implemented at the local level. I feel  that local  industry
 has  both  an obligation and  an opportunity  in  this
educational regard.
   Local  industry is   best  situated to  "know"  its
community, its attitudes and its awareness. That industry
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also knows best its own needs for waste management
facilities; local industry can best justify its needs in terms
of facilities, investment and jobs. Such advocacy by local
industry will require a real commitment, one that has not
been apparent to date.
  In the case of the surface finishing industry and metal
finishing in particular, it may be that the relatively small
size  of many of  its constituent member companies
precludes much involvement. And this circumstance may
suggest there  is a role,  a public education role, for
professional and trade organizations such as AES.
  If there is a role for AES, the question  arises: What
message   ought   AES   and   its  representatives   be
advocating?
  We suggest the message to the public might contain the
following elements:
   1. Clarify   the  connection  that  exists  between
     standard of living and generation of industrial
     wastes.
   2. Identify the need for industrial "waste baskets."
     The need for waste management facilities grows
     in proportion to living standards even though
     manufacturing processes  are being improved to
     reduce  wastes  and more  wastes  are being
     recycled and exchanged every day.
   3. Edify as to the basic spectrum of characteristics
     that are injurious  to  public  health and the
     environment, i.e., toxic, radioactive, reactive,
     corrosive, and ignitable,  and differentiate from
     these the nature of the surface finishing industry
     .wastes,  particularly those residuals  or wastes
     produced by the chemical treatment facilities of
     the industry.
   4. Edify as to the various waste disposal facilities to
     clarify  differences  among  municipal waste
     facilities for  disposal of  household refuse and
     sanitary wastes, hazardous waste facilities for
     disposal, destruction and storage of chemical
     wastes and special waste  facilities for storage of
     residuals produced by the chemical  treatment
     facilities of the surface finishing industry.
   5. Edify as to the need for segregated landfills, to
     keep industrial wastes separate from residential
     and commercial refuse thereby minimizing the
     likelihood of formation of leachate which would
     have adverse impact on groundwaters.
   6. Edify as to need for state involvement in the
     siting process  on a basis which provides for
     public participation in the evaluation of social
     and economic issues. To be emphasized: Local
     control is not likely to solve problems.

A Caveat: Things  May Not Be What They Seem
  The  current popular view is  that public opposition to
new disposal facilities is growing and future sites may
even have to be located on Federal and State lands.
However,  there  are  recent  instances  of approved
applications for  sites owned by the private sector. Are
such approvals  exceptional or might  they indicate a
trend?
CONCLUSIONS
  Regulations and societal pressures are reducing the
available  disposal options for  the  surface  finishing
industry.
  There is need for involvement at the state level in the
siting aspect of the growing problem facing the surface
finishing industry  of finding safe, legal locations for
disposal of residues from waste treatment.
  State involvement is more  likely to  be successful if
siting  procedures  include   public  participation  in
resolution of social and economic issues.
  Education of the public is a necessary precondition for
productive participation in the siting process.
  The  surface  finishing industry and  perhaps its
associated institutions such  as  AES  have a role in
increasing the public's awareness of the problem  and
potential solutions.

REFERENCES
  1. John  P. Lehman, "Status of Office of Solid Waste
    Activities,"  Second   Conference  on  Advanced
    Pollution Control for the  Metal Finishing Industry,
    EPA  600/8 - 79-014 NTIS, Springfield, VA 22161.
  2. Committee  Print,  "Hazardous Waste Disposal -
    Report," September 1979, Committee Print 96 1FC
    31, Supt. of  Documents, U.S. Government Printing
    Office, Washington, DC 20402.
  3. American Electroplaters' Society, letter December 6,
    1979,  to Members   of  Electroplating  Industry,
    Industry Survey for  Centralized Waste Treatment
    Study.
  4. Myron Browning, John Kraljic & Gary S. Santini,
    "Metal   Finishing  Sludge  Disposal; Economic,
    Legislative and Technical Considerations for 1979,"
    Second Conference on Advanced Pollution Control
    for the Metal Finishing  Industry, EPA-600/8-79-
    014, NTIS, Springfield, VA 22161.
  5. Comptroller General, Report to The Congress of
    The United  States; "How to Dispose of Hazardous
    Waste—A   Serious  Question  that  Needs to be
    Resolved,"  U.S.  GAO  Publication  CED-79-13
    December 19, 1978.
  6. State of Michigan, Hazardous Waste Management
    Act. Act No. 64, Approved July 25,  1979.
  7.  New  York  State  Environmental  Facilities
    Corporation, letter, September 1, 1979, to Governor
    Hugh Carey,  et al, with Booz, Allen &  Hamilton
    Report September 1, 1979.
  8. National Solid  Wastes Management Association,
    "Position  Statement  on  Siting  of  Waste
    Management Facilities."
  9.  Booz, Allen & Hamilton, Report for The New York
    State Environmental  Facilities  Corporation
     September  1,  1979, page 111-11.
  10.  Hazardous  Waste Report, Volume 1, Number  5,
    October 8, 1979, "Mediation/Compensation May be
     Applied to Siting Decisions," p. 4.
  11.  Donald  Andres, "Hazardous Waste Management
     Heads  out  of Adolescence," Waste Age January
     1980, p. 40.
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                               Group  Treatment-
                          Options and  Economics
                               Erich W. Salomon and Edward H. Comfort*
                                               ABSTRACT

                   Group treatment is one alternative for firms faced with the problem of compliance with
               pretreatment regulations whereby they may achieve the benefits of economy of scale. A
               preliminary study of the concept as applied to the plating firms within Hunting!on Industrial
               Park, Providence, R.I., was conducted. It was found that, with the assumed ten participating
               firms, substantial savings could be realized. The effects of financing cost and wastewater hauling
               charge on savings achieved were investigated, as were the benefits of installation of a piped
               wastewater collection system. The most cost-effective decision for each participating firm was
               identified. An approach to financing the proposed facility is outlined.
INTRODUCTION
  The  Environmental Protection Agency is currently
proposing  and promulgating  a series  of  industrial
wastewater pretreatment regulations that will reduce the
introduction  of   industrial   wastewater  pollutant
parameters  to  Publicly  Owned   Treatment  Works
(POTWs).
  The metal finishing industry, because the nature of its
waste discharge is such that it can seriously interfere with
the proper operation of  POTWs, will  be one of the
industries most affected by these regulations.1 Various
process wastewater control and treatment technologies
will be required, which could have an adverse economic
effect, especially for small plants with limited personnel
and capital.
  At  last  year's  joint  EPA/AES  Conference on
Advanced  Pollution  Control, EPAs  Centralized
Treatment Program2 was described.  It was pointed out
that the Office of Research and Development at EPA had
sponsored research to investigate means of reducing the
anticipated economic impact on industry of compliance
with pending wastewater  and solid waste regulations.
Regional centralized treatment was one promising means
identified;  economy  of  scale   and improved  waste
management  are   primary  benefits.  The  results  of
preliminary studies on the economies of  the centralized
treatment approach were  also presented at last year's
conference.3 It was shown there that the major portion of
the economy of scale benefit of the centralized treatment
concept could be realized when as few as ten shops decide
to participate in the arrangement (Figure 1).
  While other  papers at this conference report on the
present status  of research on the regional centralized
treatment approach, this presentation is directed at a case
study of the private group treatment  option. Group
*Erich W. Salomon
 Lang Jewelry Company
 Edward H. Comfort
 CENTEC Corporation
treatment, as the term is used here, refers to the joint
establishment of a waste treatment facility by a group of
shops  in close  proximity,  having  similar  wastes.
Ownership, management, and operation would generally
involve  the   participating  companies  themselves,
although a number of variants are possible. The group
treatment facility, while primarily intended  for  the
benefit of its members, could in addition offer to treat the
wastes  of  other small  shops  having  similar waste
constituents.
  Huntington   Industrial  Park, Providence,  Rhode
Island, is a modern industrial park which includes about
a dozen firms involved significantly in electroplating. All
but one or two of the companies are primarily engaged in
the manufacture of jewelry. Ten of the firms have agreed
to  participate in a  preliminary investigation of  the
technical and economic feasibility of establishing a group
treatment facility to treat their wastes.  This paper
presents the status of that investigation.
                    of the

                    plane I
                  Number Of EC
Fig. 1—Effect of Centralized Waste Treatment Systems on Capital Cost
Per Plant (from reference 3).
                                                  135

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BACKGROUND
  Pretreatment standards' for the electroplating point
source category were published on September 7, 1979,
with  an effective  date  of  October  9,  1979,  and  a
compliance date of October 12, 1982. The regulations
identify eight subcategories to which modified effluent
limitations  apply.  Those of primary  concerns to  the
plants in Huntington Industrial Park are the Common
Metals  Subcategory  and   the Precious  Metals
Subcategory.   The  major  difference  between  these
subcategories  is the addition of a limitation on  the
discharge of silver in the case of precious metals. The City
of Providence presently  intends  to enforce standards
identical to the Federal requirements.  The existence of
the  1982 compliance  date  means that  methods  of
complying  with the pretreatment regulations must  be
considered  at  an early stage. Thus,  EPA's Office  of
Research and  Development has sponsored the present
study of group treatment  at Huntington Industrial Park
at this time as a case study which might be useful as a
guide for similar industrial groupings.
  The Providence, R.I.  region, in which Huntington
Industrial Park is  located, presents a unique situation
with regard to electroplating concentration. No other
area  in  the country  has such  a high  proportion of
electroplating   firms  with  respect   to  the  general
population.   The city  presently  receives  large
concentrations of metals in its influent, and calculates
that it discharges as much as $30,000 worth of silver each
week into  Narragansett  Bay.  The jewelry industry  is
heavily represented. While it has been estimated1 that
compliance with  pretreatment regulations may force
about 20 percent of firms in the job shop  sector out of
business nationally (and other estimates have placed this
figure at between 30 and 60 percent)1, the regional impact
of such closures, were they to occur, might be expected to
be nowhere of greater significance than in the Providence
area. A group treatment facility at Huntington Industrial
Park, then, in addition  to serving its founding  firms,
would have the further potential of providing economical
waste  treatment  to those  small job shops  in close
proximity which might otherwise be severely impacted.
  Such group treatment facilities are becoming common
in parts  of Europe and in Japan. Switzerland and the
Pforzheim  region  of  Germany  have instituted  such
arrangements. In  Japan, with government assistance,
electroplaters  have relocated to parks where they can
easily  share waste treatment technology. "In the  last
several years no fewer than ten industrial  parks [one firm
to each building] and factory apartments [one building
co-owned  and  occupied   by  several  firms]  for
electroplaters  have  been  planned   and  constructed
throughout the country."4
  Chuo  Electroplating Industrial Park, built on  five
acres on an island in Tokyo Bay, is the largest  of the
parks. Nineteen platers are included (ten of them small
job shops forming a united company). The opportunity
to relocate and to redesign production lines resulted in
modern  in-line recycling and recovery  systems within
each member  shop. Combined process water discharge
was reduced to a tenth of what it had been—from 300,000
gallons per day to 30,000 gallons per day.
  The collective treatment facility at Chuo Industrial
Park  includes technologies  for nickel  and  copper
recovery (by ion exchange and electrolysis), chromic acid
recovery from contaminated  chromium plating baths
(electrodialysis), a regeneration  system for spent ion
exchange cartridges, and conventional precipitation and
dewatering  facilities   for   settling  out  solids  and
concentrating  sludges.  Fixed expenses  of the  joint
treatment facility  are  shared monthly by  all of the
members, regardless  of the  extent to which they have
used the facility,  on  the  basis of the area which each
member occupies in  the  park. These expenses include
wages and the cost of  servicing the debt. On the other
1 batch dumps over a one-month period to find a daily
f mean. Results of the first  method  was used to assit in
concentration of each type of waste sent to the collective
facility by the member.
  In the United States, there have been previous studies
of the group  treatment  concept.  The Environmental
Protection Agency provided a grant in 1977 to study the
feasibility of  joint  treatment  of  plating  wastes  in
Taunton,  Massachusetts.5  A  unique  feature  of this
region, however,  was the fact that local pretreatment
regulations, more  stringent than existing direct discharge
limitations, had forced most potential participants to
have already committed  to  a treatment scheme. Thus,
only three firms participated in the study. Because the
firms were some distance apart, and because only piping
of  wastewater   was  considered,  it   was  found
uneconomical  to  jointly  treat concentrated rinsewater,
but it was found that a joint facility to treat batch dumps
in common could provide an operating cost advantage.
Certain institutional  problems were identified, such as
the need to insure that feasibility of the arrangement did
not depend significantly on future business decisions of
one  of the participants.  Financing, at the time of the
study, was found  most  likely to depend on the existence
of a single company financially strong enough to borrow
the necessary  funds. The concept was found  to have
considerable  promise, but  was  not suitable  for the
particular participants and circumstances existing in
Taunton at that time.
   At present the Brooklyn  Economic  Development
Corporation is studying the concept of a "Plating City",
wherein some of the electroplating industry in Brooklyn,
New York, would be consolidated in an industrial park
incorporating  cogeneration and  joint  wastewater
treatment facilities. The initial study shows considerable
potential cost  benefit to  the participants. While the
plating city concept, unlike the  present study, involves
moving of platers and energy costs reduction through
cogeneration, the Brooklyn study did find that a group of
ten  assumed  platers  (consisting  of eight  small and
medium shops and two large shops) would reduce both
their investment  costs  and their annual operating costs
each by a factor of approximately 2 by joint rather than
individual treatment.
  , Huntington Industrial  Park  is  located within
Providence  at the Cranston, R. I. boundary. It is well
served by highways and nearby access ramps. Although
on the outskirts of the city of Providence, it is  centrally
located with regard to  the bulk of the electroplating and
jewelry industry in the area.
   The park is about ten years old. Although not planned
as   an  electroplating  park,  there  is  presently   a
concentration  of plants performing  plating. Eleven
plants within the park fall into that category. Each of the
firms is in the business  of jewelry manufacturing with the
exception of one plating job shop and one electronics
concern. The plants involved range in size from 25 to 350
employees. The average number of working days per year
                                                     136

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 for these firms is 242. All are one-shift operations, and the
 length of a shift is eight hours in all but two cases.
   Several of the firms perform precious metals plating.
 Gold  and silver are generally recovered  using  in-line
 processes (electrolysis, ion exchange). Most of the firms
 make extensive use of cyanide baths. There is very little
 use of chromium (chromium was found in small quantity
 in the effluent of only two  plants). In addition to cyanide,
 typical effluents include copper, nickel, and zinc. Some
 effluents show substantial iron. Little cadmium or lead is
 in evidence.
   Each  of  the companies presently discharges  its
 industrial  waste streams  to  the City of Providence
 POTW. Each of the firms may expect to be impacted to
 some  extent  by  the  mandated  requirements  for
 pretreatment.
   Figure 2 presents a sketch noting the location of the
 firms performing plating within the park.
   A  preliminary analysis was performed  in order to
 investigate the  technical  and  economic feasibility of
 establishing a joint treatment facility within Huntington
 Industrial Park to treat the wastes of the platers in  the
 park. Transport of the wastes by both piping and truck
 transport was considered.  The next section of this paper
 discusses the collection of data and the assumptions
 made for the  purpose of performing the analysis.

 DATA PREPARATION
   The analysis which follows evaluates the benefits of
 group treatment when compared with the alternative of
 each plant performing its own treatment. The cost model
 used  computes investment and  operating costs  of the
 treatment technologies employed based on flow rates and
 pollutant concentrations.
   In order to determine wastestream flows and pollutant
 concentrations being discharged by the firms in the park,
 CENTEC  engineers and technicians  spent the week of
 February  15,  1980,  at Huntington Industrial Park
 collecting the needed data. Ten firms indicated sufficient
 interest in  the project to allow a sampling team of three
 persons to spend, on average, one-half day in each plant.
   Wastewater streams were divided into cyanide-bearing
 and other (general acid/alkali).  The flow from the first
 running  rinse following each cyanide bath (expected to
 carry most of the cyanide to the sewer) was measured and
Figure 2.
 a composite sample of the cyanide stream was prepared,
 the contribution from each rinse being proportional to
 the flow rate  which had been determined. In addition,
 samples of the final effluent were obtained. Each of the
 plants' final effluent, at the point measured, consisted
 only  of process water. At one plant,  samples  were
 obtained of four different types of process solutions just
 prior to scheduled  batch dumping. The layout of each
 plating line was determined  and schematic drawings
 prepared. Information on type, volume, and frequency of
 each  batch dump was obtained. Rinse stations on each
 plating line  were  examined  to  note those  at which
 meaningful flow  reduction  measures  were in place
 (countercurrent rinse, still-rinse, etc.), and those which
 were  candidates for  incorporation  of  flow-reduction
 measures. The percent of normal production underway
 at the time of sampling was noted for each firm.
   Samples collected  from  each plant (except for  two
 which were not in operation at the time of the visit) were
 submitted to CENTEC Analytical Services, Inc., Salem,
 Virginia.  Analyses  were performed  for total  cyanide,
 cyanide amenable to chlorination, cadmium, chromium
 (total and  hexavalent), copper, iron,  nickel, lead, zinc,
 and silver. Concentrations  measured  were corrected to
 full production based on the assumption that wastewater
 flows are unchanged regardless of the level of production.
 The final effluent flow rates, generally not convenient for
 measurement,  were  calculated  by  multiplying   the
 measured  cyanide  stream  flow rate by the  ratio of
 measured total cyanide concentrations, cyanide stream
 to final effluent. Analyzed concentrations were corrected
 for batch dumps using actual concentration data for the
 one plant where batch dump  samples were taken; the
 remaining  plants' concentrations were adjusted using
 average pollutant data for each category of batch dump
 as supplied  by  the  Manufacturing  Jewelers  and
 Silversmiths of America, Inc.7 Two  methods of batch
 dump adjustment were used. In the first, all dumps with a
 frequency  of  once  each two  weeks or greater were
 considered to have occurred on the same day. This gave a
 worst  case  figure  for  comparison with the  one-day
 maximum regulations. The second method averaged all
 batch dumps over a one-month period to find a daily
 mean.  Results of the first method were used to assist in
 determining which plants might exceed maximum limits.
 Results of the second method were used to represent the
 average daily pollutant load requiring treatment.
   The two plants which are potential participants,  but
 which were not in operation at the time of sampling, were
 represented as the average of the other firms for which
 data was available.  Flow rates  for the ten plants ranged
 from 4,000 to 65,000 gallons per day. Every plant except
 one was found to exceed cyanide limitations on the final
 effluent. That plant, because its effluent flow is less than
 10,000  gallons  per  day,  did  not  exceed  applicable
 limitations  with  regard to  any pollutant parameter.
 Nevertheless, it was included  in the analysis because,
 should local regulations ever impose the same limitations
 for all parameters presently indicated for plants with
 flows  greater  than  10,000 gpd, it would  be out  of
compliance for some parameters.
GROUP TREATMENT ANALYSIS
  The CENTEC Centralized Treatment microcomputer
model was used to analyze the data described above. The
analysis is basically a trade-off of the economy-of-scale
                                                    137

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savings resulting from joint treatment against the added
costs resulting from the need to transport the wastes. The
model consists of  a series of treatment process cost
equations, based on U. S. EPA published relations.8'9 All
costs are updated by use of appropriate cost indices. The
model selects the most economical decision for each firm
from among four allowed alternatives:
  (1) Send all wastewater to the group treatment facility
(GTF).
  (2) Send all cyanide-bearing wastewater  to the GTF;
treat other flows in-house and send dilute sludge to the
GTF.
  (3) Treat all flows in-house; send dilute sludge to the
GTF.
  (4) Perform all treatment processes, including sludge
dewatering, at the individual plant.
  Treatment  processes considered  are  conventional
cyanide  oxidation,  physical/chemical  treatment
(neutralization, precipitation, flocculation, clarification
and thickening), and dewatering by filter press or vacuum
filter. Dewatering to 20 - 30% solids content is considered
essential whether performed in-house or at the GTF,
since future disposal regulations  will not  allow dilute
sludges  to  be placed  in landfill, and since  volume
minimization  is  required  to minimize transportation
cost.
  Plants which decide to ship wastewater to the GTF are
required to install sufficient 5,000-gallon tanks to hold
separately  one day's  production of cyanide and  non-
cyanide wastewater. The savings to each plant resulting
from installation of countercurrent rinse at rinse stations
not presently so equipped (if there is room) is computed.
If such savings are positive, the plant is charged with the
cost of  such investment and installation, and  the
appropriate waste stream flows are reduced accordingly.
  Transportation to the group treatment  facility was
assumed initially  to be  by 5000 gallon tank truck. The
alternative of piping all wastes to the GTF was also
considered and is discussed in a  later section. The cost of
shipping 5000 gallons by truck to the GTF was varied
from $20.00 to $40.00. (A typical charge for wastewater
hauling is $40 per hour.) The interest rate on borrowed
funds was varies from 6 percent to 18 percent. Each plant
was  assumed  to  require a 20% return on investment
before  committing  capital  to  in-house  treatment
technology.  That is, a  plant is considered to  ship  its
wastes to the GTF unless  by constructing in-house
treatment facilities  it can realize a savings  providing a
return  on invested capital of at least 20%.
  Electric utility costs, a component of operating costs,
were calculated by using the $.07/kwh rate prevailing in
the   Providence  area.   In  addition,  operating labor,
maintenance, and chemical costs are computed for each
process. The capital cost of the group treatment facility is
computed as the sum of the investment in each treatment
process, multiplied by a factor of 1.65 which accounts for
ancillary  costs of  GTF construction.10  These  costs
include  site  work, excavation,  shelter,  laboratory,
electrical installation, controls, piping, etc., in adding to
such non-construction cost as A/E fees, legal fees, and
contingency.
  Such a factor is not applied  to the  cost of treatment
processes installed within an existing  plant,  since it is
assumed that  necessary shelter, utilities, etc.,  already
exist.
                       Table 1
          HUNTINGTON INDUSTRIAL PARK
     Group Treatment Analysis Parameter Values

  FINANCIAL DATA
    Interest Rates & Equipment Life
     Interest Rate                    12%
     Return on Investment             20%
     Equipment Life                   15 years
    Transportation and Power Costs
     Transportation Cost
     Cost of Electrical Power
    Cost Indexes
     Ceman Cost Index
     Chemical Plant Cost Index
$30.00 ($/5000 gal)
0.07 ($/KWH)
198.00
246.90
     Chemical Wholesale Price Index   287.20
  GROUP TREATMENT FACILITY
    Identification
     Region Name
     x Location
     y Location
     Number of Plants
     Number of Routes
    Operational Time
     Hours of Operation
     Days of Operation
    Processes Considered
     Chromium Reduction
     Cyanide Oxidation
     Physical/Chemical Treatment
     Sludge Dewatering
     Storage Capacity
Providence
0.00 (miles)
0.00 (miles)
10
1
16 (hours/day)
300 (days/year)
  Table 1 shows the values of the financial parameters
and the group  treatment facility constants used in the
analysis.
RESULTS OF ANALYSIS
  The calculated annual operating results for the region,
consisting of the ten participating firms, are summarized
in Table 2. The annualized investment costs shown there
represent  the  amortization  of  the  initial  capital
investment at 12% over  15 years. Table 2 shows that,
although the total waste hauling charges in the park for a
year come to $124,540 (this total includes amortized in-
plant storage costs as well), an overall annual savings of
$119,735  is  realized when compared to the  costs  of
treatment without the existence  of a GTF.
  Figures 3 and 4 show the effect which the financing cost
and the transportation charge have on the overall savings
achieved.  (It has  been assumed that the  same cost  of
money applies to financing of individual plant treatment
construction and to construction of the group treatment
facility.) Figure 3  shows that the annual savings increase
rapidly  as the interest rate increases.  This is because the
greater  the cost of financing, the more significant the
economy of scale factor becomes. Of course, the cost of
servicing the debt  increases as financing charges increase,
but  the savings  make  group  treatment even  more
attractive as interest rates rise.
  Figure 4 shows the same information plotted as annual
savings  vs. the transportation  charge. As the  cost  of
hauling each 5000 gallons of wastewater from each plant
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Table 2
REGIONAL SUMMARY
Huntlngton Industrial Park
Hauling Cost = $30/5000 gallons Interest Rate = 12%
Total Plant Total Plant
Investment Operating
(Annualized) Costs
W/O
GTF $180,639
With
GTF 31,704.4
Savings $148,935
$183,489
29,147.1
$154,342
Total Plant
Chemical Total
Costs Plant Costs
$29,730.4 $393,858
4,303.41 65,154.8
$25,427.0 $328,704
Total
Transport
Costs
$0.00
124,540
$-124,540
Total Annual
Total Regional
G TF Fees Costs
$ 0.00 $393,858
84,428.8 274,123
$84,428.8 $119,735
Table 3
GROUP TREATMENT FACILITY CONFIGURATION

-
Process Required Capacity
1-Chromium Reduction
2-Cyanide Oxidation
3-Phys/Chem Treat.
4-Sludge Dewatering
5-Storage
0.0 gal/day
20,535.1 gal/day
27,500.9 gal/day
84.6 Ib/day
27,500.9 gal/day
Process and Fee Structure •
Annualized Operating
Investment Costs
$ 0.0 $ 0.0
5,751.7 5,776.0
17,973.9 10,008.9
6,287.6 2,323.6
6,560.9 0.0

Chemical
Costs
0.0
26,051.9
3,694.3
0.0
0.0

Total Costs Fee Rate
$ 0.0 $ 0.0
37,579.6 0.0080 $/gal
31,677.1 0.0050 $/gal
8,611.2 0.4402 $/lb
6,560.9 0.0010 $/gal
to the GTF doubles from $20 to $40, the savings decrease
by an amount between 12 and 20 percent depending on
the  interest  rate.  So  it is  advisable that the GTF
subscribers take care to find the most efficient hauling
means available.
   The capacity of each treatment process at the GTF
required to service the needs of the members is shown in
Table  3.  Since there is virtually no chromium  in the
wastewater of the participating plants, no provision for
hexavalent chromium treatment is made. The total flow
to the  GTF is found to be little over 25,000 gallons per
day. This is substantially less  than the total present
wastewater flow of 300,000 gallons per day from the ten
plants. This is because: (a) the model found that all plants
would find it cost-effective to reduce flow  by installing
counter-current rinses and/or still rinses at rinse stations
             ~ 170
             o
             ~ 160
             £ 150
              120

             5 110


             < 100
                     Interest Rate (Percent)
where that is possible, and (b) two plants, having some of
the largest flows, elected (based on the analysis) not to
send all of their raw wastewater to the GTF.
  Table 3 also shows a summary of all costs associated
with  operating each treatment  process  at  the  GTF,
including the amortized investment cost. A fee for use of
each  process is then established (break-even operation
for the GTF is assumed here), so that each participant is
charged based on the volume of wastes which he sends to
each process.
  Table 4 lists each plant by code and shows the option
chosen by each plant and the flows to each GTF process
from each plant. Plant No. 1 found transportation of the
raw wastewater to be so expensive that it determined its
most cost-effective solution  was to  provide  in-plant
treatment through the clarification step and to send the
                170

                160

                ISO

               , HO

                130

                120

                110

                100
                                                                                  I   I  I   I
                                                                                Transportation Costs
                                                                               (Dollars Per 5000 Gallons)
Figure 3.
Figure 4.
                                                     139

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Table 4
Option Chosen By Each Plant and Flows to Each Process
At The Group Treatment Facility
^ Average Daily Flows to Group Treatment Facility
Plant A/0 nptinn C.hnoorj " M y
-Wastestream to GTF- Cn Oxidation Gal Phys/Chem Trim Gal Sludge Dewatering Ib
1 3- only sludge 0.0 0.0 2.2
2 1- all flow 7797.5 94936 21.1
3 1- all flow 549.5 1693 0 10 2
4 1- a" fow 639.0 818.5 1.7
5 2- Cn and sludge 646.5 646.5 8.9
6 1- all flow 904.2 2562.0 6.8
7 1- all flow 1476.8 2216.1 0.5
8 1- all flow 970.5 1389.1 4.1
9 1- all flow 1235.0 1553.3 1.6
10 1- all flow 6316.0 7126.7 27.5
Table 5
INVESTMENT REQUIRED WITH AND
WITHOUT GROUP TREATMENT
In-Plant Invest, w/o Group Treat. $1,229,864
In-Plant Invest, with Group Treat. $215,673
Capital Cost of the GTF 287,991 503,664
Capital Savings $726,200
Table 6
GROUP TREATMENT FACILITY
CAPITAL COST BREAKDOWN
Cyanide Oxidation $ 23,059
Phys/Chem Treatment 72,496
Sludge Dewatering 42,772
Storage 36,066
Laboratory, Shelter, etc. 113,598
Total $287,991
iilute sludge only to the GTF. Certainly that option
choice could be changed based on segregation of certain
bear the costs of stream segregation, storage provision,
and wastewater flow reduction (included as part of
transportation costs in Table 2). The two plants which
elected to install some inplant treatment (under this set of
assumptions) would have that capital cost in addition.
PIPING OF WASTEWATER TO THE GTF
While truck hauling of wastes was assumed in the
previous analysis, the possibility of constructing an
industrial wastewater sewer system within the park was
considered. A double pipe system, designed to carry
cyanide and non-cyanide wastes separately, was
evaluated. Two designs were considered: One, a
collection system based on gravity flow, the other a
pump-assisted system. Figure 5 shows a schematic of the
collection system (single pipeline shown) with manholes
indicated (17 per line). The basis of the cost estimate is
shown in Table 7, and Table 8 presents the breakdown of
the estimated cost.
With installation of such a system for collection of
wastewater, the total costs of construction are as shown
below:
Cost of the GTF Construction $288,000
Cost of the Sewer Collection System 344,000
$632,000
Allowance for Additional GTF Flow 150,000
$782,000
accomplishment of more flow reduction than the model
assumptions allowed. Plant No. 5, with a small cyanide
stream flow but a large acid/alkali flow, chose not to
treat cyanide in-plant but to sent the cyanide wastes to the
GTF. Nevertheless, the large acid/alkali flow was found
to be more economically treated in house, sending only
the dilute  sludge to  the  GTF.   Again,  other  waste
concentration measures could change that solution.
  Table 5 shows a comparison of the capital investment
in treatment equipment required with and  without the
group treatment facility. The capital cost of the GTF
itself is only 23% of the total in-plant investment required
without group treatment. This ratio corresponds closely
to the estimate shown in Figure 1 (taken from Reference
3) for 10 subscribing plants. Table 6 shows the capital
cost breakdown for the group treatment facility. This is
the amount which would have to be financed jointly by
the participants. In addition, each  plant would, have to
                            Key.

                            Peak Cyanide Flow in cfs
                            Peak Acid/Alkali Flow in cfs

                            • Manhole Numbers
Figure 5.
                                                    140

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                                                     Table 7
                                     COLLECTION SYSTEM COST ESTIMATE
                                       ASSUMPTIONS AND PROCEDURES
   Design 1
       Based on peak flows (2.0 times present actual average
       daily flow) during actual hour of plant operation only.
       Collection system configuration as shown in Figure 5 for
       single system. Actual system will use same trends for
       collection pipe wherever possible.
       Design cost estimates.
       - Local (Providence, R.I.) materials and  labor costs.
       - Depth to groundwater assumed = 6'
        (trench  will be dewatered using  native materials, as
        necessary).
       - Select backfill used to protect pipe (@ 8CF/LF).
       - Economy for using same trench for 2 systems - 25%.
       - Asphalt replacement  necessary for 8  ft. width along
        20% of trench length  (1.6 SF/LF).
 Design 2
   • If local codes do not permit use of minimal slopes for
     small diameter pipes (even though no gross solids are
     anticipated), it may be necessary to consider a design
     alternative to the proposed gravity collection system.
     One alternative would involve installation at each site of a
     collection sump for each waste stream,  a low horse-
     power pump (3/4 hp or less), and controls. The previously
     designed gravity collection system would simply receive
     wastes by pumping at a uniform rate when a sufficient
     waste volume has accumulated at each location, thereby
     avoiding low flow volumes and velocities. Costs are
     estimated to be $2,000 per installation for 20 installations,
     totaling  an  additional $40,000 (in excess of Design  1
     costs).
   Choice of this mode of wastewater collection would
eliminate most of the annual hauling expense (storage
and truck transport)  shown  in Table 2, although the
portion related to in-plant flow reduction would still have
to  be borne.  Amortizing  the cost  of  sewer system
installation over the same 15 years at 12% results in an
annual charge of $50,568, certainly comparing favorably
with the total annual transportation charges shown in
Table 2. But it must be emphasized that,  even if wastes
were  to  be  piped  to  the  GTF,  maximum  waste
concentration through flow  reduction would  still be
required in order to  keep the GTF treatment  process
costs close to the estimate shown.

FINANCING AND MANAGEMENT ALTERNATIVES
  The group treatment concept, as the term has been
used here, requires that some or all of the companies with
wastes  to  be treated share in the ownership and/or
management arrangement.  A  group of firms, such as
those  at  Huntington  Industrial   Park,  has several
alternatives  for  financing   of the proposed  facility.
Among  these are conventional bank loans,  industrial
revenue  bond financing, and  industrial revenue  bond
financing with special SBA  repayment guarantee.
  The proposed  facility will apparently be eligible for
either  of two  alternative tax treatments."  The  first
alternative  involves depreciation of the useful life of the
pollution control  equipment  by  any  IRS-approved
method, coupled  with the full 10% investment tax credit.
Under the second  alternative, rapid amortization  of
pollution control facilities through  Section  169 of the
Internal  Revenue Code  may be  chosen.  If the facility
Table 8
Cost Estimate
Huntington Industrial Park Wastewater Collection System
Quantities Engineering
Item No. Units Units Unit Cost
Pipe, including excavation
placing, jointing, and
backfilling:
6" PVC 8770 LF 25 00
8" PVC 1650 LF 30.00
SUBTOTAL
Economy - use single
trench for placement of
both pipes where possible;
Deduct 25%
SUBTOTAL
Manholes 34 EA 1500.00
Select Backfill 1540 CY 8.00
Dewatering 5210 LF 1.50
Asphalt Replacement 900 SY 2.50
SUBTOTAL
A&E @ 10%
Contingency @ 15%
TOTAL



Estimate Cost
219,250
49,500
268,750
-67,190
201,560
51^000
12,320
7,820
2,250
274,950
27,500
41,240
$343,690
~ $344,000
                                                     141

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qualifies, the investment cost may be written off over a
60-month period, but only one half of the investment tax
credit, applicable to the year of purchase, may be taken.
Should an incorporated GTF venture show an operating
loss, the ability of any of the participating firms to apply
that loss against  its own business profits may be severely
limited, since only  a  firm owning at least 80% of the
treatment  facility  could  consolidate  the  financial
statements.  Such tax implications of group  treatment
require   detailed  investigation   for  each  proposed
arrangement. The financial summaries included in this
paper have omitted income tax considerations.
  Conventional  bank loan  financing  of the group
treatment  facility  is  a  possibility. The  individual
companies  involved in the ownership may each qualify
for  a portion of the loan. The loan could be made either
directly to the firm involved or to a corporation formed
by the firms to own and operate the facility. In either case,
the  bank would look to the assets and credit-worthiness
of the individual firms.
  If applications for  a  conventional loan result in a
turndown, it is possible to qualify for an SBA "economic
injury loan" under the Pollution Control Loan Program.
Rates are at below-market interest. Roughly one-quarter
of  such  loans   made  through last  year  were  to
electroplaters."
  Perhaps  the most  attractive  financing  for  such a
venture is through the issuance of tax-exempt industrial
revenue bonds. Such bonds are issued by a public entity.
Were such  bonds to be issued to finance the proposed
Huntington Industrial Park group treatment facility, the
likely issuer would be the  Rhode Island Department of
Economic Development.
  Until recently, such bond issues were possible only for
large enterprises in strong financial  position, since  the
investor,  must  rely  on  the credit  of the firm  for
repayment. But in June 1976 the SBA received authority
to  guarantee loans to eligible small businesses for  the
acquisition of pollution  control facilities. This  SBA
guarantee  may be for an  amount of up to five million
dollars, the full  amount of principal and interest, and
may run for a term of up to 25 years. The funds raised by
the public  entity (R.I. Dept.  of Economic Development
in this case) would  be loaned to the participating firms.
The repayment of these funds by the firms would then be
guaranteed by the  Small Business Administration. To
qualify for the loan guarantee, each firm participating in
the ownership arrangement must meet the definition of a
small business (for electroplaters, one definition is a firm
with fewer than 250 employees) and must have been in
business for at  least  five years, at least three  of them
profitable. In addition, the participating companies must
be  financially able to service the debt. But, when  tax
exempt  bond financing  is  combined  with the SBA
guarantee  feature,  the resulting AAA rating provides
small businesses with the most favorable financing rates
possible, rates heretofore available only to the largest
concerns.
   Preliminary discussions with a potential underwriter
have been held relative to the financing of the Huntington
Industrial Park group treatment facility. In practice, such
as  underwriter,  in conjunction  with  local  bond counsel
and the issuer, put together the financing package. While
joint treatment  facilities  for electroplaters  have not yet
been financed under this program, similar joint treatment
ventures have been  or are  being financed  under  the
program for a group of cheese processors, a group of
potato cooperatives, and others. A practical limitation
may be the fact that when more than three or four firms
are involved in the ownership, the administrative costs of
putting  together the  package may become excessive.
Because  fees for bond  counsel, the SBA  guarantee,
underwriting  costs, etc.  must come  out of the loan
proceeds, the  advantages of this approach  cannot be
realized when the  amount to be financed is less than
$100,000. Were 1-4 of the firms in Huntington Industrial
Park to propose to own and manage the group treatment
facility under  this  SBA  guarantee  program, the SBA
would be interested in  assuring that firm  contractual
arrangements  give  those  firms  not participating in
ownership a guarantee of future access and fair charges.
  Platers interested in investingating the SBA Pollution
Control  Financing Guarantee Program  should contact
the SBA, Pollution Control Financing Division, Office
of  Special  Guarantees,   1815  North   Lynn  Street,
Magazine Bldg.,  Rosslyn, Virginia  22209,  (703) 235-
2900.
RECOMMENDATIONS  FOR  HUNTINGTON
INDUSTRIAL PARK
  The proposed Group Treatment Facility has been
shown, based on a preliminary analysis, to be feasible for
Huntington Industrial Park and  to effect considerable
cost savings for the participants when compared to their
costs of complying  with  the pretreatment  regulations
individually. Installation of an industrial sewer system
within the park, while more than doubling the demands
for initial capital, would be cost-effective in the long run.
While the  analysis  performed  has  considered  only
conventional  treatment  processes, further study  is
warranted   to  investigate  the  benefits  of  recovery
technology for copper and nickel at the GTF. The process
capacities at the GTF have been arrived at by considering
the needs of the group treatment participants within the
park. Relatively small additional investment would allow
process capacities to be increased so that the same facility
could accept similar  wastes from some of the very small
job shops in the region,  those which otherwise would be
most severely impacted by the pretreatment regulations.
  Each  participant  must carefully analyze his  own
operation and take steps to concentrate the wastes which
he sends to the GTF. In the preceding analysis, it has been
assumed that the flow rate of all running rinses would be
minimized by installation of counter-current rinsing at all
stations where this was calculated to be cost effective. In
addition, careful sampling of all running rinses should be
performed  to determine which can go directly to the
POTW without pretreatment. In place of, or in addition
to counter-current rinses,  still rinse  installation prior to
each running rinse should be evaluated. When the still
rinse could not go directly to the sewer, the still rinse tank
would be emptied into a storage tank to await shipment
to the GTF. Of course, each plant should be certain that
good housekeeping practices are in effect to minimize
dragout, control spills, and recover plating bath solutions
where possible.
  Figure 6  shows the actions required by each of the
plants which are able to  concentrate their  wastewater
sufficiently  to  ship it  economically  to  the  GTF.
According  to the preceding analysis, nearly all of the
plants at  Huntington  Industrial Park  fall into this
category.  Those  plants  which,  even  after  flow
                                                     142

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       Dilute Rinses to POTW
        After Equalization




*-~
Cyanide Still Rinses
Acid/Alkali Still Rinses -
Concentrated
Cyanide Bath Dumps

1—
Concentrated
Acid Bath Dumps
Cleaning Adds
and Bases
                                    Action Required:
                                      • Install Still Rinse Tanks
                                      • Minimize Drag-out
                                      •• Storage for Pickup
                                    >AII to
                                   Centralized
                                   Treatment
                            ion Required.
                            Install Still Rinses and Minimize Rinse


                            Install Treatment for Rinses
                            Install Dilute Sludge Treatment

                                    3-Percent Solids to
                                    Centralized Treatment
                         ^ Concentrated Baths to
                          Centralized Treatment
                                                                                    Pickle Liquors and Alkaline
                                                                                   ' to Centralized Treatment
Figure 6.
Figure 7.
minimization,  still  could  not  afford  to  ship  their
wastewater to the GTF, would exercise the option shown
in Figure 7, involving some in-plant treatment with dilute
sludge shipped to the GTF. This option may apply to one
or two of the  plants  within  the  park, although, with
maximum attention to flow reduction, it is believed likely
that those plants would also send all of their wastewater
requiring treatment to the GTF.
   The capital required has been estimated as $300,000 to
$800,000.  The   SBA  Pollution  Control  Financing
Guarantee Program  is very attractive for such amounts,
particularly when combined with an issue of tax-exempt
bonds. It is recommended that the Huntington Industrial
Park participants contact the SBA Office  of  Special
Guarantees, an experienced  underwriter, and the R.I.
Department of Economic Development to explore this
financing option.
   The  Group   Treatment   Facility  at   Huntington
Industrial Park would require a permit from the State of
Rhode Island authorizing it  to operate as Hazardous
Waste  Treatment  Facility.  Truck  hauling  of   the
wastewater would be required to comply with applicable
regulations  concerning   the  transport  of  hazardous
wastes. The GTF will,  in addition, be faced with the cost
of  disposing   of  the  dewatered  sludge  in  an
environmentally safe manner, in an approved hazardous
material  landfill  (assuming   that  such  sludges   are
classified as hazardous). These costs were not considered
in the earlier analysis of savings to be achieved through
group  treatment,  since the same costs, proportionately,
would have to be borne by the participants were they to
choose to treat their wastes individually. The GTF may,
in fact, effect some savings here since it would be shipping
to the landfill by 20 cubic yard truck loads rather than by
the drum. One of the first actions to be undertaken by the
participants  should  be  identification of  an ultimate
disposal site and the associated costs, since  no approved
hazardous material disposal site exists within the State of
Rhode Island.
  This   preliminary  analysis  has  illustrated   the
considerable potential of the group treatment concept for
reducing the costs of pretreatment to the industrial park
participants.  As has been noted,  the proposed  facility
also  has potential for service to  a  wider community,
offering small plating job shops a means of complying
with regulations while minimizing economic impact. The
GTF costs and savings presented here have been based on
operation of the facility on a two-shift basis. Additional
capacity to treat wastes from outside the park could be
gained  by going to three-shift operation. Or,  the initial
facility  design could be resized based  on single shift
operation, providing considerable  room to increase
operating hours and to process additional wastes.
  The next phase of the work required to bring a project
such as this  to fruition should  include, in addition to
definition  of  the  financing   obtainable,   detailed
engineering design. This would include site selection and
layout,  treatment  process  specification  and  layout,
transportation system  and/or  piping  system design,
detailed capital and operating cost estimates, leading to
working drawings and specifications. Resource recovery
at the  GTF  should be evaluated and included  in  the
design if economic. Detailed  engineering design coupled
with firm  financing plans will allow  accurate projection
of the costs to each participant.
REFERENCES
 1.  Federal  Register, September  7,  1979, "Effluent
    Guidelines  and  Standards;  Electroplating  Point
    Source   Category;   Pretreatment   Standards  for
    Existing Sources.
 2.  Craig, Jr., Alfred B., "EPA's Centralized Treatment
    Program,"  paper  presented  at  the   Second
    Conference on Advanced Pollution Control for the
    Metal Finishing Industry, Feb.  5-7, 1979.
 3.  Minor,  Paul   S.,   and  Roger  J.  Batstone,
    "Applicability of the Federal Republic of Germany's
    Centralized  Waste Treatment  Approach in  the
    United States,"  paper  presented  at  the  Second
    Conference on Advanced Pollution Control for the
    Metal Finishing Industry, Feb.  5-7,  1979.
 4.  Saito, M., and A. Nakomura, "Resource Recovery,
    Water  Saving,   and  Waste  Treatment in  Chuo
    Electroplating Industrial Park," April 1978.
 5.  "Group Treatment of Multicompany Plating Wastes
    (The Taunton Silver Project)",  EPA-600/2-79-102,
    EPA ORD, July 1979.
                                                      143

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6.  "Plating City:  Feasibility Study of Electroplating
   Industry  Consolidation,"  report  prepared  for
   Brooklyn  Economic Development  Corporation,
   Gibbs & Hill, Inc., November 1979.
7.  Thibault,  James  E., Manufacturing  Jewelers and
   Silversmiths,  of America,  Inc.,  private
   communication, 13  March 1980.
8.  Development  Document for  Proposed Existing
   Source  Pretreatment  Standards  for  the
   Electroplating Point Source Category, EPA 440/1-
   79/085, February 1978.
 9.  Economics of Wastewater Treatment Alternatives
    for the Electroplating Industry, EPA 625/5-79-016,
    June 1979.

10.  Construction  Costs  for  Municipal  Wastewater
    Treatment Plants, 1973 - 1977, U.S. EPA, Office of
    Water Program Operations, January  1978.

11.  Sacks, Sheldon, "Federal  Financial Assistance for
    Pollution Abatement", paper presented  at  the
    Second Conference  on Advanced Pollution Control
    for the Metal Finishing Industry, February 5-7,1979.
                                                   144
                                                                           i U.S GOVERNMENT PRINTING OFFICE 1981-757-064/0290

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