oEPA
United States
Environmental Protection
Agency
Industrial Environmental Research EPA-600/8-79-014
Laboratory June 1979
Cincinnati OH 45268
Research and Development
Second
Conference on
Advanced Pollution
Control for the Metal
Finishing Industry
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U S Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields
The nine series are:
1 Environmental Health Effects Research
2 Environmental Protection Technology
3 Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
6 Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8 "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the "SPECIAL" REPORTS series This series is
reserved for reports targeted to meet the technical information needs of specific
user groups. The series includes problem-oriented reports, research application
reports, and executive summary documents. Examples include state-of-the-art
analyses, technology assessments, design manuals, user manuals and reports
on the results of major research and development efforts.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161
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EPA-600/8-79-014
MAY 1979
Second Conference
On Advanced Pollution Control
For the Metal Finishing Industry
PRESENTED AT:
ORLANDO HYATT HOUSE, KISSIMMEE, FL
FEBRUARY 5 - 7, 1979
Co-sponsored by:
• The American Electroplaters1 Society
• The United States Environmental Protection Agency
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. Environ-
mental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents neces-
sarily reflect the views and policies of the U. S. Environ-
mental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement
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 research papers and
discussions of the "Second 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 at lERL-Ci to solve the pressing pollution
problems of the metal finishing industry. It is hoped that
the content of the conference and the subsequent
proceedings will stimulate industry action to reduce
pollution by showing through government-sponsored
research at lERL-Ci that viable control options are
available. Further information on these projects and
other metal finishing pollution research can be obtained
from the Metals and Inorganic Chemicals Branch, IERL-
Ci.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
Hi
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TABLE OF CONTENTS
INTRODUCTION
George S. Thompson, Jr. and J. Howard Schumacher, Jr 1
SESSION I
REGULATORY STATUS
EPA WELCOME TO THE SECOND CONFERENCE ON ADVANCED POLLUTION CONTROL
FOR THE METAL FINISHING INDUSTRY
Dr. Eugene E. Berkau 2
STATUS OF EFFLUENT GUIDELINES AND PRETREATMENT ACTIVITIES OF EGD
Robert B. Schaffer 3
STATUS OF OFFICE OF SOLID WASTE ACTIVITIES
John P. Lehman 6
EPA'S METAL FINISHING RESEARCH PROGRAM
George S. Thompson, Jr 10
SESSION II
SOLID WASTE CONTROL
METAL FINISHING SLUDGE DISPOSAL; ECONOMIC. LEGISLATIVE & TECHNICAL CONSIDERATIONS FOR 1979
Myron E. Browning, John Kraljic & Gary S. Santini 26
THE STATUS OF THE EPA/AES SOLID WASTE PROGRAM
Kenneth R. Coulter 32
METHODS & TECHNOLOGIES FOR REDUCING THE GENERATION OF ELECTROPLATING SLUDGES
Dr. Clarence Roy 34
APPLICABILITY OF THE FEDERAL REPUBLIC OF GERMANY'S CENTRALIZED WASTE TREATMENT APPROACH
IN THE UNITED STATES
Paul S. Minor and Roger J. Batstone 38
EPA'S CENTRALIZED TREATMENT PROGRAM
Alfred B. Craig. Jr 45
SESSION III
PRETREATMENT
ECONOMICAL PRETREATMENT — A JOB SHOP CASE HISTORY
Fred A. Steward and Henry H. Heinz 50
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CITY OF GRAND RAPIDS. MICHIGAN PROGRAM OF INDUSTRIAL WASTE CONTROL
James A Biener 55
SELECTING THE PROPER UNIT PROCESSES FOR THE TREATMENT OF ELECTROPLATING WASTEWATERS
A F Lisanti and Sam O Megantz 64
FEDERAL FINANCIAL ASSISTANCE FOR POLLUTION ABATEMENT
Sheldon Sacks 76
SESSION IV
SUMMARY OF EVENING SESSION 83
SESSION V
WASTEWATER TECHNOLOGY
WATER RECYCLING AND NICKEL RECOVERY USING ION EXCHANGE
Kenneth Price and Charles Novotny 85
FIELD DEMONSTRATION OF CLOSED-LOOP RECOVERY OF ZINC CYANIDE RINSEWATER
USING REVERSE OSMOSIS AND EVAPORATION
Kenneth J McNulty and John W Kubarewic^ 88
MEMBRANE PROCESSES FOR METAL RECOVERY FROM ELECTROPLATING RINSE WATER
John L. Eisenmann 99
AN EPA DEMONSTRATION PLANT FOR HEAVY METALS REMOVAL BY SULFIDE PRECIPITATION
Murray C. Scott 106
THE DEVELOPMENT OF AN ACTIVATED CARBON PROCESS FOR THE TREATMENT OF CHROMIUM (VI)-
CONTAINING PLATING WASTEWATER
C. P Huang and A R Bowers 114
REMOVAL OF HEAVY METALS FROM BATTERY MANUFACTURING WASTEWATER
BY CROSS-FLOW MICROFILTRATION
Dr John Santo, Dr James Duncan. N. Shapira and Charles H. Darvm 123
SESSION VI
ANALYTICAL METHODS AND AIR
STATUS OF ANALYTICAL METHODS FOR CYANIDE
Gerald D. McKee 131
PRUDENT WASTE TREATMENT MONITORING, ANALYTICAL CONTROL AND TESTING
Frank Altmayer 135
EVALUATION OF SOLVENT DEGREASER EMISSIONS
Vishnu S. Katari, Richard W. Gerstle and Charles H. Darvin 138
vi
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INTRODUCTION
The U. S. Environmental Protection Agency's Metals
and Inorganic Chemicals Branch and the American
Electroplaters' Society, Inc., jointly designed a broad-
scoped colloquium, "The Second EPA/AES Conference
on Advanced Pollution Control for the Metal Finishing
Industry," in Kissimmee, Florida, on February 5 7,
1979. The primary purpose of this conference was to
perpetuate the dialogue established at the first EPA/ AES
meeting (1978) between key members of EPA and the
metal finishing industry. The proceedings, contained
herein, of this second conference reflect the focal 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 deal with the ramifications
of these regulations. Research on analytical methods and
air-pollution control strategies was also addressed at the
conference and reports of this work appear in these
proceedings.
The program of the conference was broken into three
segments: regulatory; research, design and development;
and an exchange of viewpoints between members of
government and industry. Since attendees of the first
conference placed extreme emphasis on the problems of
dealing with wastewater and solid waste, the primary
purpose of the first segment of the second conference was
to provide conference participants with a detailed
understanding of the potential impact of current and
future regulations in these two important environmental
areas. Key EPA officials, representing the Effluent
Guidelines Division (water) and the Office of Solid
Waste, described the procedure by which EPA prepares
and promulgates regulations, with special emphasis on
direct impact to metal finishers.
The second segment was divided into five areas: (I) an
overview of EPA's research program for pollution
problems regarding air. water and solid waste as it relates
to the metal finishing industry, (2) control of solid waste,
(3) pretreatment of wastewater. (4) recovery of chemicals
from wastewater, and (5) air-pollution control and
methods of analyzing potentially harmful liquid and
solid discharges. Programs sponsored by both EPA and
industry were presented to provide the audience with a
better understanding of the significant research and
development in these five areas.
The third segment, entitled "Exchanging Viewpoints,"
was conducted during a three-hour evening session. A
panel comprised of EPA officials and industry
representatives opened the floor to a free discussion in
order to permit EPA to clearly understand those research
needs considered by the industry to be of paramount
importance. This objective was fulfilled as research needs
became evident during frank discussion between the
audience and the panelists.
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 two EPA regulatory groups
affecting the metal finishing industry, as well as
presentations by various parties actively addressing
research and development in this same environmental
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
Metals & Inorganic Chemicals Branch, EPA
J. Howard Schumacher, Jr.
Executive Director
American Electroplaters' Society, Inc.
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EPA Welcome to the Second Conference
On Advanced Pollution Control
For the Metal Finishing Industry
Dr. Eugene E. Berkau*
I would like to extend to you EPA's "welcome" to this
Second Conference on Advanced Pollution Control for
the Metal Finishing Industry. In addition, I offer a
special thanks to Howard Schumacher and his staff, to
Jerry Schmidt, Dick Crain, Clarence Roy, and to other
AES officials 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. I think, for instance, that when you hear
George Thompson's presentation on our metal finishing
R&D program, you will see that much of the R&D work
which has been initiated this past year resulted from your
comments at the last year's conference. This year we
again solicit your participation and comments after each
presentation and particularly at the Tuesday evening
discussion session to be moderated by Ken Coulter.
Members of my staff who are responsible for the
development and implementation of the metal finishing
R&D program are George Thompson, Chuck Darvin,
Fred Craig, and Mary Stinson. 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 comments along with the
conference proceedings.
The major goals of the R&D efforts are 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 last year's 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. This year we are focusing on the Agency's water
and solid waste programs which we feel, will have the
greatest impact in the near term.
I personally would like to encourage you to critically
evaluate the ongoing and planned R&D activities in view
of the R&D goals 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 oppotunity to meet many of you during the next three
days.
'Dr Eugene E. Berkau, Director
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati. Ohio
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Status of Effluent Guidelines
And Pretreatment Activities of EGD
Robert B. Schaffer*
The final pretreatment regulations have not yet been
made public. I will be able to tell you something today
that will be of interest and importance to you. I do have
one very serious constraint, however; it is the formal
constraint not to discuss major issues with regard to
proposed regulations between the close of the comment
period and the final promulgation. So I apologize that I
will not be able to discuss them in great detail today.
However, there are a number of things that I can relate to
you. 1 will relate a summary of the public comments that
were received on the proposed regulations that are now in
consideration. I may not touch on every one or one that
you particularly subrrftted yourself, but I will try to give
eight or ten general comments where we have received a
number of comments. I hope to provide you with a feel of
when we expect to make a final decision on those
regulations. Following that, what 1 really can talk about
and what I am primarily engaged in at this point of time,
is our effort on the BAT Review which 1 am sure will be of
interest to you. 1 can talk in detail about the effort—
where we are, what our approach is, what we have found
to date, and what we might do about it. So, with those
preliminary notes, let me start by summarizing the
comments that were received. There are other speakers
from the Agency who will be discussing items of interest
to you that relate to the guidelines and that is
appropriate. I saw that Gary McKee will be here to talk
on cyanide analysis. A representative from EPA's Office
of Water Enforcement, who is intimately involved in the
pretreatment regulations, will be here tomorrow night to
answer questions with regard to how those regulations
might be implemented.
Let's dive into the public comments. Number one on
the list, believe it or not, is cyanide. Several comments
received suggested that the analysis was not appropriate
nor were the levels that were specified.
A number of commenters also suggested that cyanide
was a compatible pollutant, that is, when discharged into
a sewer it does not impact or pass through a treatment
plant. In regard to cyanide, others are suggesting levels
that might be more appropriate for pretreatment. They
fall around I mg/liter of total cyanide.
•Robert B. Schaffer, Director
Effluent Guidelines Division
U. S. Environmental Protection Agency
Washington, DC 20460
Several commenters question the need for amenable
cyanide limitations for wastes that are discharged into a
publicly-owned treatment works. In this case, amenable
cyanide was suggested as the only appropriate limitation,
so we are getting comments on both sides of the issue.
Many folks expressed a concern with regard to
concentration-based limitations and that they would
penalize those facilities that were employing water
conservation practices. An optional mass-based
limitation was included in the proposal to overcome that
problem.
There were many comments that addresed the total
metals limitation that was suggested as one of the
options. Many thought that it was not supported by the
documents that were provided and that it would be very
difficult to meet by certain facilities.
As you can imagine, we got many comments with
regard to the impact of the regulations, some forecasting
a higher impact than we thought, others forecasting a
lower one. Generally, however, most thought they were
understated and, therefore, our judgments in the
proposal were not, in fact, economically achieveable.
In addition, there was a request by several commenters
to include specific monitoring requirements in the
regulations. Some commenters requested clarification as
to whether or not daily sampling was required to meet a
30-day average and definition as to how the samples
should be taken and composited over a working day. So,
there was a bit of concern regarding monitoring
requirements.
Many folks also felt that the cost for sludge disposal,
which we placed at !2e/gallon, is low. We did get
additional estimates and additional data on costs that
ranged from 25c to $1 per gallon. Also, there were many
comments that requested that EPA participate actively in
establishing a national network of disposal sites. Maybe
Jack Lehman will be talking to you about that very topic
and be able to answer questions about that.
There was an additional comment as to whether or not
hexavalent chromium was an appropriate limitation,
since the waste discharges into a highly reducing
environment (the sewers) and that the hexavalent
chromium will be rapidly reduced to the trivalcnt state.
Therefore, the limitation was not necessary. A limitation
on total chromium was suggested as the alternative.
There were many comments concerned with the small
plater cutoff. Concern about small platers disrupting
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small sewage plants was voiced and it was suggested that
the regulations were not nearly stringent enough. There
was a particular request that the Agency specify the state
and local government's right to impose stricter
regulations.
We have had two sets of regs, one for interim final
which cover cyanide destruction and hexavalent chrome
reduction. The compliance data is July 12, 1980. We
expect we will go "final" with the second, the proposed
pretreatment regulations sometime in the middle of this
calendar year. That will initiate the time clock for
achieving these limitations as three years after that date.
As you may be aware, this was done purposely in order to
stretch out the time that would be required for
compliance with both regulations in order to minimize
the overall economic impact.
That covers the major comments that we have received
to date—they are public information, they are available
in our offices and will be made available through
information services once they are all catalogued and
compiled.
1 would like to turn now to our ongoing work with
regard to our BAT studies. As you know, we will be
reviewing all of the previous regulations, interim final
and proposed, with regard to the toxic pollutants that
were included in the 1977 amendments that I am sure you
are all familiar with. We have, as far as our approach
goes, expanded the list of chemicals that were identified
in the amendments from 65 to 129. We are proceeding to
evaluate various discharges, in all industries,
electroplating being one. Our initial effort evaluates each
subcategory and screens the discharge. Screening means
taking a representative sample from a number of plants in
a subcategory and running a very sophisticated chemical
analysis on it. These analyses (GCMS, Gas
Chromatography Mass Spectrometry) are expensive. It
is pushing the state-of-the-art as far as analytical
capabilities are concerned and is one reason why the
Agency undertook to do the sampling and analysis itself.
This particular analysis looks at 114 of the 129 pollutants
that are of concern to us. In this first effort our primary
objective is to identify the presence or absence of these
114 organics and to roughly quantify the amount that is
present. We do this in order to be able to focus our
attention on the organic pollutants of primary concern so
that when we go back and take a further look we will be
able to focus in on things that are of most significance.
We will then run through what we call a verification
program, wherein we once again confirm the presence or
absence of the materials that we found and make an effort
to quantify them and to evaluate the appropriate
technology for their removal. The costs are also
determined. We will then take this information and go
through much of the same procedures that were gone
through in previous guideline efforts.
Since we do not have "approved" methods for many of
these materials, and in the Clean Water Act there is a
section which requires analytical methods to be approved
before they can be used in Permits, we have had to look at
various other options of regulating. We are looking at
indicators. We are looking at surrogates. We are looking
at the need for specifying the limit for each of the 114
pollutants that we have found. One of the things we are
considering in this is the treatability or compatibility of
these organic materials with POTWs. We have a pretty
substantial effort underway to try to determine whether
or not these materials will be adequately treated in a
municipal system, whether or not they pass through,
whether they have an adverse impact on the disposal of
the sludge. We will be taking all of these into
consideration as well as the volume and mass of materials
that are being discharged to determine whether or not the
regulation is appropriate. It is conceivable that the study
we have underway will be equal in stringency to our
previous regulations or more stringent than those
regulations, depending upon the levels of these priority
pollutants, the treatability of these pollutants, and the
discrimination as to necessity of regulation. We, of
course, found a few metals in discharges, as we expected,
but we also did find some organic materials present.
There were probably fifteen to twenty depending on the
particular subcategory and we have made a
determination as to which ones we are going back to look
at in more detail. For your information, those which we
have found to be most prevalent are 1-1 trichlorethane, 1-
2 trichlorethylene, methylene chloride, bisi-
hexylphthalate, and toluene. The levels that we have
found range between five micrograms per liter and 200
micrograms per liter. The rough total of toxic organic
pollutant levels that we have found to date is about 300
micrograms or 0.3 mg per liter. We had a suspicion that
we would find some of these because some of them are
found in some degreasers, etc. that we might have in job
shops. Phthalates, which we are finding everywhere,
come from plastics. Anytime that water comes in contact
with plastic, we seem to find certain levels of these
phthalates. There is an environmental concern with
regard to all these pollutants. We will be publishing, for
instance, the frequency of the presence of these materials
in waste waters. To achieve proper control of the serious
problems that we find, we will be again promulgating
four sets of regulations from this study. We expect to
review BAT, Best Available Technology Economically
Achievable, for direct dischargers. We expect to be
reviewing in detail and ultimately modifying
pretreatment regulations and we will be establishing new
source performance standards for both direct and
indirect dischargers. We are looking closely at new source
performance standards. We feel that in an industry,
where there is rapid growth, or where there is significant
impact, that one of the most important long-range things
that we can do is to establish very tight, new source
performance standards. The design options, location
options, and a number of other options make it much
easier to take steps to control toxic pollutants when a
particular facility is constructed. We also expect that any
revised standards that come out separately will be built
upon, and compatible with, the other regulations that
either have been promulgated or proposed.
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I do not believe that we are going to invent a new
technology with these regulations. We hope there are new
technologies available at your option, but they will be
built upon, and we expect, compatible with those that we
have been discussing over the years. We do not have a
present schedule for our BAT studies and we expect them
to be proposed March 21, 1980. We will then expect the
promulgation to occur in October of 1980 which would
provide a three-year compliance time, in the area of
pretreatment, as has been the period for the interim final
and proposed pretreatment regulations.
We appreciate your continued interest and
participation with us and expect, once we are over the
hump on our promulgation of the pretreatment
regulations, to be back into more detailed discussions,
etc., with respect to our BAT study. We continue to invite
your participation, with your technical committee and
with you individually, if you so desire.
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Status of Office of Solid Waste Activities
John P. Lehman*
My purpose in talking to you today is to discuss the
hazardous waste regulations that have been sanctioned
by RCRA.
The proposed RCRA regulations, which are out for
public comment now, emphasize the responsibilities of
the generators of waste. It is the generator's responsibility
to make the decision as to whether or not he has a
regulated waste as defined in Section 3001. There are a
number of other requirements for generators in the
Section 3002 regulations. Although some generators do
dispose of the wastes in what we call on-site facilities,
these regulations apply to both on-site as well as off-site
disposal cases. This non-distinction regarding disposal
location is very important. Most state programs deal only
with off-site facilities. The federal program and all future
state programs will deal with both on-site and off-site
disposal of solid waste.
Let's assume that a waste will be shipped out for off-
site disposal. It is the generator's responsibility to prepare
a transportation manifest which accompanies the wastes.
First, the generator must determine, in advance, that the
facility to which he is sending the waste has a permit to
accept the type of waste that is being sent. The generator
fills out a manifest and gives it to the transporter. The
transporter is required by the Section 3003 regulations,
proposed in April of 1978, to take the wastes only to the
facility which has been designated by the generator. If
any spills occur en route, the transporter is required to
report it back to an emergency number. He is
subsequently required to clean it up.
The disposer is subject to the disposal regulations,
called facility standards, in Section 3004. In effect, these
define what constitutes the environmentally acceptable
management of hazardous wastes. These standards cover
treatment, storage, and various types of disposal,
including incineration, treatment, surface
impoundments, landfills, landfarms, basins. You name
it—it is there in these regulations.
The permit regulations under Section 3005 codify the
technical requirements in Section 3004. The permit
regulations are, in fact, mainly administrative
regulations. They state what you have to do to apply for
the permit; where you send it; the permit application's
contents; what happens once the permit application gets
into the system; the due process; the public hearings. The
'John P. Lehman, Director
Hazardous Waste Management Division, Office of Solid Waste
U. S. Environment Protection Agency, Washington, DC 20460
Administrator of the Agency is in the process of
consolidating this type of administrative ruling for three
different programs—the RCRA Hazardous Waste
Program, the NPDES Discharge Program under the
Clean Water Act, and the Underground Injection
Control Permit Program under the Safe Drinking Water
Act. These are still in process, but the consolidated
permit regulations are scheduled for proposal sometime
later this month. So that is basically the flow of it.
Several other aspects to this program are really
important. Section 3006 deals with state programs. It was
very definitely congressional intent, in RCRA, that the
Federal government write the national standards, but
that states carry out the programs in lieu of the Federal
government. This is very important wording in RCRA.
Similar wording is not in the Federal Water Pollution
Control Act; nor in the Safe Drinking Water Act. There,
the states may be authorized to carry out this program
instead of the Federal government. In RCRA, the states
are not merely delegated a Federal program—they have
their own program which may or may not be identical to
the national one. However, if it is equivalent to and
consistent with the federal program, other state
programs, and has adequate enforcement, the
Administrator of EPA is required by the law to authorize
the state's program to operate in lieu of a Federal
program. Therefore, the Section 3006 regulations are an
exposition of what we believe equivalency, consistency
and adequate enforcement mean with respect to state
programs. These were proposed one year ago in February
1978.
We were going to finalize these regulations when the
current efforts to consolidate the regulations (Resource
Conservation and Recovery Act, Federal Water
Pollution Control Act, and Safe Drinking Water Act)
were initiated by the Environmental Protection Agency
last summer. The Agency is currently consolidating the
state program requirements for the RCRA Hazardous
Waste Program with the NPDES (FWPCA) and the
Underground Injection Control Regulations(SDWA)so
that there will be one set of regulations that apply to state
program authorizations. Where these statutes differ.
there will be different sections in the regulations. There
will be a general section which applies to all three Acts
(Section A) and then Sections B, C, and D to deal with
specifics of each individual program. Here it is tied with
the Consolidated Permit regulations and will be
reproposed, since these changes were made to it, on the
same schedule as the Permit regulation.
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Most of the regulations that 1 have talked about to date
are in Part 250 of the Code of Federal Regulations. The
consolidated permits and consolidated state program
regulations will be issued under Parts 122, 123, and 124 of
the Code of Federal Regulations.
Last, but not least, is Sectin 3010, a notification or
registration requirement that is in RCRA. What the Law
says is that, once the Agency defines a hazardous waste
under Section 3001, everyone who is included in this new
system, that is anyone who generates, stores, treats,
transports, or disposes of any waste which is identified as
hazardous under Section 3001, must notify EPA within
90 days. This Section is, in effect, saying what kind of
notification information is required and suggests a
sample data format to be used. The Agency will use a
massive computer mailout to make it easy for everybody
to understand the regulations with which they are
supposed to comply. This regulation was proposed in
July of last year. The comment period has closed and
OSW is preparing the final regulation. Therefore, as with
Bob Schaffer's pending effluent guidelines and
regulations, I will not be able to answer too many explicit
questions about Section 3010.
Section 3001 is an important regulation. It describes
two different ways to define hazardous wastes, both
prescribed by the Act. Hazardous waste is defined by
both general characteristics and by lists. Under general
characteristics, four have been proposed. The first is
ignitable waste, chosen to avoid confusion with the term
used for flammable materials by the Department of
Transportation. Both use the same type of test technique:
a basic flash test to test the ignitibility of wastes.
Corrosive wastes are characterized based on pH for
strong acids or bases. Reactive wastes include most
explosives and anything that is of a pyrophoric nature.
And lastly, we have a characteristic for toxicity which is
related to the groundwater and, therefore, tied to the
primary drinking water standards. These standards, at
the present time, deal only with heavy metals and some
pesticides, and do not include a great number of organic
chemicals.
The first of the lists is the list of generic wastes, such as
solvents, cutting oils, etc., that are found in almost every
industrial category. Second, we found that the best way
to deal with infectious wastes was to list the sources of
infectious wastes. Certain kinds of laboratories and
departments in hospitals constitute this second list. Next,
and this is really the heart of it all, process wastes have
been listed by SIC code. The intent was to make the
regulations easy on the generator. Rather than saying, for
example, wastes that contain mercury in concentrations
greater than 5 parts per million are hazardous, which
would imply that everybody had to run out and test their
wastes for mercury to see whether they had more or less
than that amount, that decision has been made for you.
Wastes from certain types of processes that EPA expects
have a high content of hazardous materials are covered.
We have listed wastes by process; therefore, no testing is
required. If an industry waste is on a list, it is in the
control system. There are about 175 wastes in those first
three lists.
In addition, we are faced with the problem of people
throwing away pure chemicals. Consider a bad batch in a
production process that is off spec or chemicals for which
the shelf life is over. These wastes fall into a fourth type of
list in which we reference the DOT poison A and B
categories, the priority pollutants, and the rebuttal
presumption pesticides. In other words, discarded pure
or almost pure chemicals that are on those lists are also in
the system. There are about 275 of those waste chemicals
listed. So, overall, there are on the order of 450 items that
are on the hazardous waste lists.
Now, each of the four characteristics I mentioned
earlier is keyed to a test protocol to determine whether or
not a waste meets those characteristics. Probably the
most interesting and perhaps the most controversial
aspect of the regulations is related to the toxicity
characteristic. The test procedure is called the extraction
procedure (EP). What the extraction procedure is
supposed to do is to provide a model of what might
happen to a waste if it is improperly disposed. In other
words, can toxic constituents of the waste leach under
reasonably normal conditions of rainfall, etc.? Will that
material leach out of the waste in sufficient quantities to
present a threat to groundwater and hence to drinking
water? It is basically a screening mechanism to help
decide what is and is not a hazardous waste. As I
mentioned, there is not a general characteristic for
organics but we have in the December 18, 1978 Federal
Regulation, an Advanced Notice of Proposed
Rulemaking indicating the Agency's intent to develop a
method for organic toxicity related genetic change
potential, for phyto-toxictty and several other forms of
toxicity. The comment period on the Advanced Notice of
Proposed Rulemaking closes on July I, 1979, so if there
are comments on the proposal, you will have until July to
comment on that.
There is also a "delisting" protocol. The Agency
recognizes that, particularly in the process stream
categorization, there may be a certain waste stream
within an industry SIC code that is not hazardous even
though a generalization about that particular industry
would indicate that it is. Individual facilities may show
EPA that a waste, even though it is listed, is, in fact, not
hazardous. Following the protocol, it can be taken off
these lists or "delisted."
Generators are responsible for many things under
these regulations. First of all, I mentioned they are
responsible for making the basic decision, "when is a
waste a hazardous waste?" This can be done in three
ways. First, they check the various lists and see if their
waste is on any of the lists - the only decision we make for
them. Second, they can test their waste against those
characteristics that are defined or, last, they can just
simply declare the waste to be hazardous and enter it into
the system. Generators are also required to prepare the
shipping manifest mentioned previously, to keep records
and to make reports.
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There are certain exemptions, however. First, all
household wastes are exempted because that was cited in
the legislative history. POTW sludge is exempted because
the Clean Water Act Amendments of 1977 called for
regulation of municipal sludge under Section 405 of that
Act. Industrial sludge is not exempted. A conditional
exemption is provided to retail establishments and
farmers provided that they dispose of their wastes in state
approved facilities. There is one last exclusion which is
very controversial. If you would like to comment on this,
we would be happy to have you do so. There are a very
large number of potential sources of hazardous wastes,
but a great majority of those generate waste in a relatively
small quantity. In other words, there is a very sharp break
in solid waste generation quantities, as most of the wastes
are generated by a relatively small number of large
generators; and yet there are a large number of generators
producing small amounts. So, what we have tried to do
here is balance the risk to the environment of having
relatively uncontrolled amounts of waste against all of
the administrative hassle of bringing a large number of
generators into the system for record keeping purposes.
Therefore, a lower waste amount cutoff at approximately
100 kilograms per month is proposed. One hundred
kilograms is roughly one half of a 55 gallon drum ... 220
pounds is about half of a 55 gallon drum.
The disposal facilities regulations, as 1 mentioned
before, are the basis for the Permits and provide design
and operating standards for storage, incineration,
treatment, and land disposal in its various modes.
Another aspect of the facility standards is financial
responsibility. This is, again, a new departure from other
regulations you may be familiar with. The law requires us
to establish standards of financial responsibility for those
who want to be in the business of disposing of hazardous
wastes. It is as simple as that. Basically, the problem has
been that people go into this business accepting wastes
for disposal at a price. They collect a lot of money. Then
they walk away with the money and leave the wastes for
someone else to clean up. This financial responsibility
clause is to prevent that type of situation. The Agency
intends that people have enough money to adequately
close these facilities, and make sure they have some type
of liability coverage in case there are accidents. In the case
of disposal facilities such as landfills, surface
impoundments, etc., we want to make sure that once the
facility is closed, it is monitored for 20 years after closure
to ensure that the waste is not contaminating
surrounding areas. I am sure most of you heard of the
Love Canal situation in Niagara Falls, New York where
chemical wastes buried 25 years ago have recently come
up out of the ground into people's basements and are
polluting the area nearby. Over 200 families had to be
evacuated from that area. There are histories of birth
defects in that community — a very bad situation. This
situation clearly points out that wastes do not go away.
They are basically contained or not contained as the case
may be. We want to make sure that people have enough
money to adequately monitor what is happening to these
wastes.
Now, all of this sounds very idealistic, but we do
provide some flexibility through what we call "notes".
You can imagine what the problems have been for EPA.
We are trying to define national facility standards that
apply across the board to all types of wastes, to all types
of industries; at the same time we realize that there are
individual situations that require some degree of
flexibility in terms of geology, hydrology, and rainfall.
There are all types of wastes; there are all types of
different combinations of a situation. EPA will have
national standards, but we will allow some degree of
variance from these standards by these "notes". So, read
the "notes" very carefully because they basically establish
the criteria for variance from these standards.
There are also limited standards for interim status.
There is an interim period after the regulations are final,
but before a permit is issued. So, rather than let the whole
load of all these regulations fall on people during that
initial period, a somewhat limited number of regulations
or standards have been specified that apply during that
interim status.
Lastly, there are special standards for "special" wastes.
These special wastes are of very high volume and a
relatively low environmental risk. Flyash, mining wastes,
and cement kiln dust belong to this category. Special
standards are in effect while we try to sort out what can be
done about them.
Media performance standards, in effect, override all of
the design and operating standards. Those design and
operating standards should provide the necessary degree
of environmental protection, but if they do not, the media
performance standards override them. These are
standards for groundwater protection, surface water
protection, and air. They could come into play though
they normally would not.
This program, as any new program, has a number of
issues associated with it. I mentioned two of them. The
small quantity exemption for generators and financial
responsibility requirements for disposers. There are
others. I think it would be appropriate to address some of
the other issues.
One issue is facility availability. There are many people
who, basically, are saying "Chicken Little, there will be
no facilities available for all of these wastes". Well, what
they really mean is that there will be no environmentally-
acceptable facilities for these wastes and we accept that.
Our estimate is that 90% of all disposal operations will
not meet these new requirements. We also do not expect
the world to change overnight. We are not going to
change the method of operations that each of you have
been practicing for over 100 years and just do it with the
drop of a steel curtain of regulations. This is provided for,
as I mentioned, by the interim status. In other words,
everything is going somewhere right now. We realize
that. What the interim status provides for is this: If a
hazardous waste is reported according to Section 3010
within 90 days and if a permit is applied for as specified in
the permit regulations, interim status is automatically
granted. A company can continue to do whatever it was
-------
doing until the permit is written. Now given EPA's
resources, it could easily be two years before a permit is
issued. Meanwhile, this interim status is in effect subject
to limited interim standards that I mentioned. Once a
permit is issued, there is provision for compliance
schedules to meet these new standards which may run
upwards to three years. So, what we are really saying is
that we are anticipating, approximately, a five-year
transition period between what we are doing now and
what we want to do (i.e., what will be acceptable as these
new regulations go into effect).
The second issue is that there is no provision within
RCRA for any federal support for facility construction.
There are no construction grant-type provisions in
RCRA as there are in the FWPCA.
The third point, which follows from the first two, is
that we believe it will fall to the private sector and perhaps
to municipalities to construct and operate some of these
facilities. The entire Congressional foundation of RCRA
is based on the premise, that, given a regulatory program,
there is enough capital out there that the private sector
will respond and will provide facilities that are necessary.
Therefore, there will be no construction grants.
Another issue is the economic impact of these
regulations. This is a difficult subject to talk about for
several reasons. First of all, the RCRA does not have any
reference to economic analysis in it whatsoever. The
FWPCA does and the CAA does, but RCRA does not.
So, there is some question as to whether it is even legal to
consider economics in these regulatory decisions. As you
can tell from the scope of what 1 have discussed regarding
this very important new regulatory program, it will
impact, simultaneously, practically every sector of
American industry. To undertake an economic impact
analysis of our entire industrial sector is very difficult. In
the Effluent Guidelines Program, for example, where the
regulations were tailored to a particular industry, the
Agency was able to do a very detailed economic impact
analysis for that particular industrial segment. OS W was
not able to perform this segment-by-segment analysis, so
it initiated the next level up in detail of economic analysis.
The public has access to this. What that draft (we have
only a draft of the analysis) says for the plating/ metal
finishing industry is that there is a 75 percent confidence
limit that a ten percent closure rate will result because of
the full application of those regulations. Now, 1 want to
point that out, because someone mentioned to me that
the word was going around that there was going to be a 75
percent closure. What it means is that the confidence level
of the analysis is 75 percent that there would be a 10
percent closure. However, another study OSW had done
on this indicates that, in the worst case situation, there
would be no more than a 2 percent closure. There are two
different sets of studies indicating two different results,
both of which are "worst case". Therefore, we are
conducting a much more detailed economic analysis now
and we will provide our results as a part of the final
rulemaking package. But, I do mention to you that both
the economic impact analysis and the environmental
impact statement drafts are available for public scrutiny,
and we would certainly like to have your comments on
those as well as on the regulations.
Another issue is this consolidated permit that I
mentioned to you earlier. Everybody thinks that is a good
idea on the surface, but there is some opposition to it. If
you have thoughts about the consolidated approach, we
would like to hear them too. Last year, the whole issue of
state programs was held up because it was not clear. All
of what I have said to you so far this morning is, in effect,
what would happen if EPA runs this program. States do
have the opportunity and it is Congressional intent that
states take on this program and operate it. We are not yet
sure how many states will seek this authority. We are
hopeful that all of them do. To put this into perspective,
the NPDES program has 35 states that implement the
permit program for water. So that gives you a feel for the
split, but we hoping to do a little better. Current estimates
are that about 40 states would take on the RCRA
program. When discussing consolidation of permit
regulations, etc., at the federal level, that does not
necessarily mean consolidation at the state level.
One other thing, and 1 am sure that this will be
discussed further by George Thompson and others
during this Conference, is the centralized treatment issue.
I want to point out one aspect of state regulations
impacting on this approach. If a centralized treatment
facility is constructed, more likely than not it will be a
regional facility that involves interstate transport. As you
may know, many states have felt that it is within their
power under the Constitution to impose importation
limitations or bans on certain types of hazardous wastes.
The position runs counter to the whole idea of a regional
facility. 1 think that it is important that industry
recognize this and, to the extent that you are at issue, you
should enter that debate about importation bans at the
state level. There is a lot of commotion and politics
involved in conjunction with importation bans, but we
believe that they are basically a bad public policy and that
we ought to keep open doors so that the wastes can go
where they naturally should go.
-------
EPA's Metal Finishing Research Program
George S. Thompson, Jr.*
INTRODUCTION
Why does the Federal EPA conduct research,
development, and demonstration activities on the metal
finishing industry? How does the Federal EPA establish
its research objectives? Today, 1 will answer these
questions, as well as other questions that I feel are
pertinent to your interests.
I will start by first telling you who we are. 1 represent
EPA's Office of Research and Development, specifically
the Industrial Environmental Research Laboratory in
Cincinnati, Ohio. My Branch, the Metals and Inorganic
Chemicals Branch, is responsible for conducting RD&D
activities on air, water, and solid waste pollution for a
variety of industries, including the nonferrous metals
industry, the inorganic chemicals industry, the metal
finishing and fabrication industry, and a variety of
miscellaneous industries such as glass, cement, and
asbestos. My Branch, as well as my Director's Division
and the Laboratory in Cincinnati, came into existence
three years ago as a result of a major reorganization
within EPA's Office of Research and Development. The
major benefit from this reorganization was the
establishment of a new charter directing one research
group to address pollution control RD&D for all three of
the major pollution media - air, water, and solid waste -
for specific industries. Prior to the 1975 reorganization,
water RD&D was conducted by one group, air pollution
control RD&D by another group, and in most cases these
groups of Federal researchers were physically located in
different parts of the U.S.
Our broad charter is extremely supportive to
conducting valuable research programs; we are one of a
small handfull of EPA activities that can address the
"total pollution problem." Also as a result of our broad
charter, we have the capability to interface with other
EPA offices and Federal Agencies having regulatory and
enforcement responsibilities impacting the industrial
sector. Allow me to provide a specific example that
directly addresses your interests: my staff interfaces with
the regulatory offices, such as the Effluent Guidelines
Division, the Office of Solid Waste, the Office of Air
Quality Planning and Standards, and EPA's newly
structured Office of Toxic Substances; we interface with
"George S. Thompson Jr., Chief
Metals and Inorganic Chemicals Branch
Industrial Environmental Research Laboratory-Ci
U. S. Environmental Protection Agency, Cincinnati, OH
INTERFACE CAPABILITY
A KEY TO AWARENESS
Fig. 1—Interlace Capability - A Key to Awarenets.
EPA's air and water enforcement offices as well as many
of EPA's ten Regional Offices. What does this interface
illustrated in Figure I provide? Awareness a basic
requirement for conducting valuable research and
technical support a "must" for establishing firm
technical foundations for regulatory and enforcement
actions. I must stress the following point: EPA's Office of
Research and Development is an independent function
within EPA; it does not report through line management
to any one EPA regulatory or enforcement activity. If
you're asking yourself "what does all of this mean?" - let
me summarize. Our interface with these programs, along
with our interface with you - the industry, provides us
with the awareness to structure our research activities to
be best "in tune" with the most important needs (See
Figure 2). We in research can develop and implement
programs that provide answers to key technically and
economically impacting pollution problems.
IMPORTANCE OF AWARENESS
INTERFACE
CAPAMJTY
1
AWARENESS
T
RESEARCH PROGRAM
"W-TUNE" WITH
MOST IMPORTANT NEEDS
POTENTIAL USER
COMMUNITY INPUT
Fig. 2—Importance of Awareness.
10
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MECHANISM FOR
CONDUCTING RESEARCH
4
Acnvrro
4
DCT1UMUU1.
Acnvmu
• QUANT*
• CONTRACT*
• MTDUOtHCV
M-HOUSC
Acnvmts
• TE*T AMD EVALUATION
FAOUTV
Fig. 3—Mechanisms lor Conducting Research.
HOW WE CONDUCT OUR RESEARCH PROGRAM
In the past, our metal finishing research program was
entirely "extramural," which means that we conducted all
of our research activities through outside organizations
by means of three principal mechanisms: grants.
contracts, and interagency agreements (See Figure 3). We
now have an inhouse research capability a newly
constructed research facility in Cincinnati, which we call
our "Test and Evaluation Facility." Our research funding
is presented to us each fiscal year in the form of
Congressional appropriations. We in EPA's research
office then allocate these funds to projects based upon
our awareness of technological needs. Thus, our
awareness to the most important research needs is
essential, since we are limited in our funding level.
EPA'S METAL FINISHING RESEARCH PROGRAM
My intention during this presentation is not to provide
you with the technical detail of each and every research
project in the metal finishing program, but rather to
describe the program itself. For your information, 1 have
attached two lists to this presentation: one list provides
the title, a brief narrative, and the project officer's name
and telephone number for each of the projects
comprising the metal finishing program; the second list
contains the titles and EPA publication numbers for all
of our completed metal finishing projects. If you have any
questions or comments regarding the projects or
publications as listed, please call or write my office in
Cincinnati. I will address the status of several of our key
projects during this presentation; several other important
projects will be addressed by other speakers in the
Conference's remaining sessions.
The metal finishing program is structured around the
following goals;
• Advance the state-of-the-art in air, water, and solid
waste pollution control and treatment technology.
• Provide EPA with the best technological basis for
the setting and enforcing of regulations.
• Provide to the industry the most cost effective
approaches and alternatives for complying to air,
water, and solid waste regulations.
• Ensure both EPA and the industry that the
abatement of pollution from one media will not
result in either pollution to another media or
excessive energy consumption.
• Act as a focal point for information dissemination.
These goals are not easily achieved. Everyone must
work toward them. We in the Office of Research and
Development must have a clear understanding of the
metal finishing processes and the resulting air, water, nd
solid waste pollutants generated by these processes; we
must be perceptive to both the short and long term
research needs within EPA and obviously outside of
EPA. We rely strongly on ideas, direction toward
problems, and expert advice from people like yourselves.
Our pulling together to attempt to reach these goals
has allowed my staff to structure the metal finishing
research program.
The program itself is broad with many avenues to
venture down. Its basis is problem definition and
awareness; problem solution is performed through
research, development, and demonstration.
Dissemination of results, whether positive or negative, is
accomplished by means of a variety of mechanisms (See
Figure 4).
RESEARCH PROGRAM'S APPROACH
PROBLEM
DEFINITION
-*
PROBLEM
SOLUTION
-*
DISSEMINATION
OF
RESULTS
Fig. 4—Research Program's Approach.
Let's first discuss the program's basis problem
definition. We are currently attempting to establish a
data base on the metal finishing and fabrication industry.
which by our definition includes the electroplating and
machinery and mechanical products industrial categories
established by the Effluent Guidelines Division. One
must remember that this industrial definition (detailed in
I able 1) includes a large percentage of all I). S. plants that
Table 1
Definition of Metal Finishing & Fabrication Industry
• Electroplating
• Machinery & Mechanical Products
- Mechanical Products
- Electrical & Electronic Equipment
- Photographic Equipment and Supplies*
- Copper and Copper Alloy Products
- Porcelain Enameling**
- Aluminum Forming**
- Shipbuilding**
* Research in this area conducted by lERL-Ci. Organic Chemical and
Products Branch. Cincinnati. OH.
••The current metal finishing research program has insufficient funds to
address these areas
11
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produces a vast array of products. Three years ago, we
inherited an electroplating program from our research
predecessors that was directed primarily toward
wastewater problems. We initialed and completed a
special study to define the air pollutants generated by
electroplating operations. Our next "problem definition"
acli\ii\ was started one year ago. Our goal was to design.
develop, and utili/e a data base containing process
information and associated air. water, and solid waste
data on the mechanical and electrical and electronics
products industries - two ol the largest suhcategories of
the I (fluent Guidelines Division's machinery and
mechanical products industrial category. We have
completed the design ol a computeri/ed data base to
handle the immense amount of data that we have
collected. This data base will serve three primary
functions. (I) As a sound technological data base for the
development of effluent guidelines and standards. (2) As
a priorili/ing tool for allowing us to take a broad and
complex industry and locus on the most impacting
problem areas, and (3) As a starting point for building a
data base on other portions ol the industrial sector.
The "data base' approach is one form of problem
definition - an extremely important approach especially
when a limited amount of research dollars is provided for
problem solution. Another form of problem definition
can be termed "detailed quantification." This term may
not make sense, but hopefully alter Ken Coulter makes
his presentation this afternoon, we will all have a better
understanding of its meaning. Ken will describe a
proposed research effort between the EPA and the AES
that should provide, through "detailed quantification," a
clearer understanding of the metal finishing sludge
problem. We plan to address this broadly-defined
problem area by applying the most acceptable screening
tools to quantitatively characterize the hazardous nature
of sludges. This screening should then permit us to focus
our problem solving attention on those metal finishing
sludges having the greatest environmental impact
potential.
Key Problem Definition Activities
• Air pollutants from electroplating
• Computerized data base on mechanical and electrical
and electronic products
• Planned computerised data base on metal finishing
and fabrication
• EPA AFS sludge characterization project
• Planned "Awareness Bulletin for Metal Finishing"
Before we complete our discussion on problem
definition and its importance to a good research
program, I would like to discuss awareness. We are
meeting at this three-day conference to become aware of
each other's problems and of our progress toward
problem solution. We must make each other aware. This
conference provides a perfect forum to exchange
viewpoints and knowledge. Your comments on EPA's
metal finishing research program are strongly desired.
One last point regarding awareness ... being aware of
worldwide advancements in process and pollution
control technologies could remedy many of our
problems. My office has. for the past 18 months, printed
and widely distributed a bimonthly "Awareness Bulletin
lor Nonferrous Metals." This bulletin is a summary of a
major screening of U. S. and international periodicals
and publications; it has alerted my staff and members of
the nonferrous metals industry to numerous items
enabling us to develop and implement a very productive
nonferrous metals research program. I plan to initiate an
"Awareness Bulletin for Metal Finishing" within the next
two months. Please notify my office if you would like to
be on its mailing list.
The Research Program's Product - Problem Solution
How does EPA's RD&D program address problem
solution? A variety of matrices can be formulated for
designing a metal finishing program. Let me describe the
one with which 1 feel most comfortable: The industry,
independent of the specific process technology used or
product made, can be segmented into three basic
scenarios - new plants; existing plants with no air, water,
and solid waste pollution control technologies inplace;
and existing plants with control and treatment
technologies inplace (See Figure 5). Please remember
that some of the research activities that 1 describe overlap
scenarios.
CONDUCT ROAD TO
Of KM. WATBL AND KHJD
WAIT! POLLUTION
Damn PLANT
WITHOUT
POLLUTION CONTMOU
CONDUCT IBID TO •PMVIM-PLANT
CONTROL nCMKOLOOT, TO
IPPXMNI ANBCO»T-lPHLIIirtAHAliD
WATIM LONIMJd, AND TO
•V COHTMOLUNa AM AND WATIH POLLUTANT*
Damn PLANT
WITH
TO opram MPLACC CONTHOU,
AND TO DMPOM OP ILUOQa
MFH.V
POLLUTION CONTROL*
tmiiafT
WAtnWATDI
Fig. S—Matrix Formulation ol Plant Scenarios.
12
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Research for New Plants
In the first scenario - new plants - options are available
to achieve production and pollution control goals. We
conduct research by both evaluating and developing new
production processes. Our evaluation project for new
processes was described at last year's EPA/AES
Conference; this activity with Grumman is still ongoing.
Problem Solving Activities in First Scenario
- M'ir Plant.\ L/nder (.'onxtruciion -
• New process evaluation program
• New plastics electroplating approach
• New dry circuit board manufacturing process
(planned activity)
We are currently developing under contract, a new
plastics plating approach and we are planning to
investigate a dry circuit board manufacturing process.
Are there any new "low polluting" production processes
that you can make us aware of?
Research for Existing Plants
Without Installed Pollution Controls
In the second scenario, where the plant has already
been built and is fully operational but pollution control
and treatment technologies have not been installed,
opportunities to provide solutions to pollution problems
exist. Even though the production process is inplace, it
can still be optimized to cost-effectively minimize the
generation of air, water, and solid waste pollutants.
Phase 1 of our joint project with the Metal Finishers'
Foundation on the demonstration of the HSA
Electrochemical Reactor has revealed a variety of inplant
changes that can at reasonable cost, be implemented by
plant personnel. We are currently documenting the
impacts of approximately 50 inplant changes at Varland
Metal Services, the host site of our demonstration.
Reductions in wastewater flow, pollutant
concentrations, and chemical usage have resulted. Some
of us feel that pretreatment requirements, in certain
situations, can be met or closely approached with
implementation of these inplant changes. We hope to
prove this in the very near future and possibly prepare a
documentary report for broad dissemination on inplant
changes, associated costs, and potential impacts.
Phase II, the actual demonstration of the HSA
Electrochemical Reactor, is now underway. The first
reactor will be installed on Varland's cadmium plating
line this month. During March, the second reactor will be
installed on a /inc line. Reactors will then be placed on
two to three other segregated lines and on the final plant
combined effluent. Each reactor will be operated for a
six-month period for proper validation. We will
disseminate our results to all interested parties as soon as
they become available. Our research work on
electrodialysis is continuing and John Eisenmann will
provide detail during Wednesday morning's session. We
have just completed a demonstration of insoluble sulfide
precipitation at the Holley Carburetor plant in
Tennessee. The results from this demonstration will be
published in a pending EPA report; we also decided to
prepare a full-color Capsule Report on both soluble and
insoluble sulfide precipitation, describing the costs and
technical pros and cons of each. Our soluble work is
primarily based on part of my Branch's nonferrous
metals program; specifically, we are evaluating Sweden's
Boliden primary lead and copper smelter sulfide system.
We are also currently demonstrating a filtration system
for metal-bearing wastewater which I'm sure will be of
interest to you; results of this demonstration will be
available within the next six months.
A tremendous amount of effort has been placed on
reverse osmosis by the AES and EPA's research
program. We initiated a "final" R. O. study several
months back; we have taken the best membranes, as
determined through previous research efforts, skid-
mounted them with an evaporator, and placed the system
at a plant for detailed evaluation. Our current attention is
limited to applying our R. O. skid-mounted system to
only one of the three primary wastewater extremes
affecting conventional R. O. application. I hope to
ultimately address all three extremes: low pH, high pH,
and oxidizing solutions. Ken McNulty will report to us
during Wednesday morning's session.
When considering existing plants that are faced with a
requirement to install wastewater equipment to meet
discharge limits, we saw a real need to provide assistance
in making the proper technology selection. We have
prepared a report that describes "off-the-shelf
wastewater technologies, their pros and cons, and their
capital and estimated installed and operating costs, as
well as a description of "emerging" wastewater
technologies. This report requires one more review prior
to publication and broad dissemination - your preview.
This afternoon, Clarency Roy will explain how you can
help us.
Key Problem Solving Activities in Second Scenario
- E\i.\iinK Plants Without Pollution Control* -
Inplant changes (Phase I of HSA Reactor Demo)
HSA reactor demonstration
Electrodialysis RD&D
Sulfide precipitation activities
Filtration system demo
Final reverse osmosis project
Technology/cost report
Solvent dcgreaser evaluation
Surfactant scrubbing
Gas recircuhition for VOC control
Our metal finishingair pollution research program was
described at last year's EPA AES Conference. Progress
has been made. Chuck Darvin and PEDCo's Dick
13
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Gerstlc will describe the up-to-date results from their
solvent degreascr evaluation program during Wednesday
altcrnoon's session. Research on surfactant scrubbing
has also progressed and we arc currently evaluating sites
tor a pilot demonstration. Our plans to demonstrate
process olfgas recirculation, lor volatile organic-
compound (VOC) control and cnerg\ utilization. have
not been implemented during the past year, but our work
in this area will start shortly.
Existing Plants With Pollution Controls Installed
The third scenario existing plants with inplace
pollution controls is the most difficult of the three
scenarios to address, but possibly one of the most
beneficial. Consider a plant that installed a wastewater
treatment facility se\eral years ago that now proves
inadequate due to such factors as plant production
expansion, new product lines, or more stringent
discharge provisions. Must this company "tear out" this
equipment and \enture into a new "capital intensive"
system, which may be one key factor to plant closure?
Our approach is to conduct research on optimizing
existing inplace systems to possibly prevent this
occurance.
I will briefly describe three of our research activities
that should provide assistance. The first effort is nearly
completed and is being jointly performed by Mitre and
Arthur G. McKee. The product will be a manual
describing proper design techniques and optimizing
approaches for conventional neutralization/ precipita-
tion systems. It has been designed for usage by both
consultants and plant personnel. Did you ever wonder
what effect a change in neutralization chemicals might
have on your problem of sludge generation? Let's hope
that this manual will provide you with answers to this and
similar questions.
The second effort, also planned to be in the form of a
manual, addresses inorganic sludges, processes for their
dewatering. and methods for their disposal. Funding
limitations have prevented us from completing this
manual, but \\e will do our best to get this valuable
information completed and out to you.
Key Problem Solving Activities in Third Scenario
- f.v/.s ling Plants \\'ith Inplace Pollution Controls -
• Manual of practice for conventional neutralization,
precipitation technology
• Manual on inorganic sludges
• Application of microprocessor technology
Our third primary effort is a novel one. We plan to
shortly demonstrate the application of microprocessor
technology to minimize effluent pollutant parameter
fluctuations, or, in other words, streamline the operation
of conventionally-used wastewater treatment systems.
How many of you have installed in your plant or know of
someone having inplace equipment that allows
excursions to occur? Do these excursions prevent you
from achieving your 24-hour max or 30-day average? We
have just completed a feasibility study on the
microprocessor application. The results of this
preliminary study have indicated great potential for
solving a "real-world" problem at minimum cost. 1 solicit
your comments on this approach.
Solid Waste Research Program
Before I complete this portion of my presentation. I
will describe our solid waste research program. At last
year's EPA/AES Conference, many of you made it quite
clear that you had a sludge problem. Statements were
made, such as "PL 92-500 its forcing us to clean-up our
wastewaters, but now we've got all of this sludge! What
do we do with it?" We have taken your concerns, and for
that matter, EPA concerns, and put together a program.
I've already described the EPA; AES sludge
characieri/ation project which should point us toward
those high priority sludge problems requiring the most
immediate research attention. This project is, ol course,
problem definition.
Our major activity in the sludge area for problem
solution came as a result of two separate incidences: (1)
Last year's Conference during which our Canadian
associates told us of the Federal Republic of Germany's
centralized treatment approach and (2) our
understanding of the impact of the pending pretreatment
and solid waste regulations. Last fall, we evaluated the
German centralized treatment approach and its potential
in the United States. Paul Minor will describe his findings
and observations during this afternoon's solid waste
session. We combined our thoughts and formulated our
own centralized treatment program. Fred Craig, a
member of my staff will provide some detail of this
program after Paul Minor's presentation. We have
structured our program for broad application across the
United States. It focuses on developing and proving out a
tool to alleviate the metal finishing industry's potential
financial problems associated with compliance to the
pretreatment and the solid waste regulations. Please
listen closely to what Fred describes this afternoon. He
will ask for your comments and suggestions for
improvement of our program.
Solid Waste Research Program
• EPA/AES sludge characterization project (planned
activity)
• EPA centralized treatment program
Evaluation of FRG approach
- Cadmium sludge recycle (planned activity)
- Polish sludge segregation and metals recovery project
(planned activity)
We also plan to initiate a research project on cadmium
sludge recycle. We will work with a primary nonferrous
smelting company that produces cadmium. This
14
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company will solicit cadmium-bearing sludges from
metal finishers to determine if the cadmium values can be
economically extracted either pyrometallurgically or
hydrometallurgically. If the technology can be worked
out, then a new alternative will be available to metal
finishers to remedy potential disposal problems with
cadmium sludges. Lastly, we are working with the
Institute of Precision Mechanics in Warsaw, Poland to
initiate a joint international research project on metal
finishing sludges. Our research proposal to the Polish
investigators calls for a program to develop a centralized
containment site for segregated sludges and then to
develop and demonstrate inexpensive methods for metals
recovery from these sludges. Hopefully, this project will
be approved next month for international funding; it
could provide valuable results.
I have not described all projects that are ongoing or
planned that address air, water, and solid waste pollution
control for metal finishing. Please consult the materials
attached to my presentation for a complete listing.
HOW CAN WE BENEFIT FROM EACH OTHER?
The metal finishing research program is available for
your usage whether you are with EPA or with the
industrial sector. We have published reports and are
currently addressing problem definition and solution
through active projects. We can provide you with more
detail on any of these activities if you desire.
If you feel that you have a solution to a metal finishing-
related pollution problem and would like to have our
assistance in proving out this solution, use the following
criteria to determine if we can work together:
I. The problem that you are addressing must not just
be your problem. In other words, the more
"universal" the problem, the more interest we have.
2. Your proposed solution must have economic merit.
We don't want to solve a problem with a solution
that's too expensive to adopt.
3. While your proposed solution may solve an air,
water, or solid waste problem, your solution should
not generate new pollutants or consume excessive
energy.
4. Your problem should be one of EPA concern. Our
funding is limited and unless we can anticipate a
future problem for our regulatory counterparts, we
must address solutions to key Agency problems.
5. The time required to develop and demonstrate your
solution should be in-line with the timing
constraints formed by EPA regulatory and enforce-
ment actions. Obviously, a technological break
through five years after a regulation has been
established and enforced does not have critical
impact. If your break through could lead to an
"ultimate" solution of a key problem, we may still
be interested irrcgardless of timing.
6. Your solution, after being proven out, hopefully
would be adopted by your industry and possibly by
other groups within the industrial sector. Define
potential clients for your solution.
7. Funding required to "prove out" your solution must
be within reason. Our resources are limited and are
utili/ed in a very competitive fashion. Your percen-
tage in cost sharing is a \cry good indicator ol your
interests.
The normal procedures for us to work together follow:
I. A telephone call or very brief memo to my office
that discusses the above criteria is the best way to
start.
2. If preliminary interest exists, further discussion,
preferably in person, is the next best step for provid-
ing additional detail.
3. If a mutual interest exists, your solution "program"
could be submitted as a grant proposal or unsoli-
cited proposal for funding.
4. Your submittal is reviewed for relevancy to the
Agency's program goals; it is also reviewed for merit
by in-house personnel and extramural reviewers,
including industry representatives.
5. If reviewers respond favorably, we then determine if
your funding needs can be met with our limited
resources.
6. If all looks well, we formalize our agreement and
work proceeds.
Our normal funding mechanisms with industry are
grants and competitive or noncompetitive contracts.
There are many complexities associated with funding air
vs. water vs. solid waste-related activities; my staff can
provide detail to you if you desire.
One last point regarding our working together - you
may have a potential solution to a problem that is not
relevant to the metal finishing industry, but is relevant to
other components of the industrial sector. If this is the
case, I have attached to this presentation a list of EPA
researchers who have responsibility for specific industrial
areas. Please use this list as a starting point for possible
joint research and for determining what the specific EPA
research program encompasses.
If we do not find the opportunity to work directly
together, I solicit your assistance through your expertise.
We in the metal finishing research program do not
profess to be experts; we are very knowledgeable. You are
faced with the "real world" problems that provide you
with insight and practical working knowledge. If we can
"tap" your insight and expertise to assist us in developing
better programs, we will all benefit.
15
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Tille
Attachment I
List of Ongoing and Planned Research
Activities for the Metal Finishing Industry
Narrative
Protect Officer I Number
Air I Wau-r I Solid H'u\ie Activities:
Data Base for Metal Finishing Industry
EPA AES First and Second Conferences
On Advanced Pollution Control
For Metal Finishers
Industry definition: process discussion; air.
water, and solid waste generation; control and
treatment technology,
• Electroplating air emissions have been
studied
• Mechanical and electrical and electronic
products are under study
Conference designed as forum exchange for
activities between EPA and industry
Charles H. Darvin
(513)684-4491
George S. Thompson
(513) 684-4491
Air Activities:
Low Solvent Emissions
Dcgreasing Systems Evaluation
Surlactant Scrubbing Technology
for Control of Organic Air Emissions
(Planned)
Performance of Alternate Coatings
in the Environment (PACE)
Technical E\aluations of
Reduced Pollution Corrosion
Protection Systems
Evaluation of Gas Rccirculation System
on Paint Bake Oven
Development of New Low Polluting
High Solids Coating
Side-by-side comparison of commercially
available dcgreasers with inexpensive
modifications for VOC control.
Currently locating site to demo this technology.
Evaluation of coatings that should be less VOC
polluting. Inleragency Agreement with DOT.
Evaluations conducted on new commercially -
available electroplating and surface coaling
systems.
Sampling program on auto paint bake oven to
determine VOC control and energy reduction
gained through gas rccirculation.
Interagency Agreement with USAF to develop
new aircraft (DOD and commercial) high
solids coatings that should reduce VOC
emissions.
Charles H. Darvin
(513)684-4491
Charles H. Darvin
(513) f.84-4491
Charles H. Darvin
(513)684-4491
Hugh Durham
(513)684-4491
Charles H, Darvin
(513)684-4491
Charles H. Darvin
(513) 684-4491
Water Activities:
HSA Flcctrochemical Reactor
Demonstration
Documentation of Recycle Reuse
Inplant Technologies (Planned)
Wastcwaier Technologies and Associated
Costs for the Small Elcctroplatcrs
Feasibility Stud) of Application of
Microprocessor Technology for
Wasicwater Pollution Control
Demonstration of cost effective (modular in
design) wastcwatcr technology. Potential for
non-sludge generation. Minimum production
loss during hook-up. Minimum plant floor
space requirements.
• Phase I: Identification and implementation
of mplant changes
• Phase II: Demonstration of reactor
Planned activity to disseminate inplant
technology information to reduce wastewater
flow rates, pollutant concentrations, and
chemical usage. Recycle reuse research needs
defined.
Report outlining the pros and cons of various
wastewater technologies and associated capital
and operating costs. Emerging technologies
also described. Planned to assist the electro-
plater in deciding on which technology to use.
Feasibility of application investigated for variety
of industrial waslewatcrs for purpose of
minimi/ing pollutant parameter excersions.
Specific system designed and priced for conven-
tional wastewater electroplating systems
(oxidation reduction neutnili/ation
precipitation sludge blanket control.)
Ben Smith
(513) 684-4491
George S. Thompson
(513) 6X4-4491
George S. Thompson
(513)684-4491
Ben Smith
(513)684-4491
16
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Title
Narrative
Project Officer/ Number
Demonstration of Application of
Microprocessor Technology for
Wastewater Pollution Control (Planned)
Manual of Practice for Conventional
Neutralization/ Precipitation
Wastewater Systems
Demonstration of Microfiltration System
for Acidic Metal-Bearing Wastewaters
Field Demonstration of New
Reverse Osmosis Membranes for
Closed-Loop Treatment of
Electroplating Rinsewater
Demonstration of Insoluble
Sulfide Precipitation on Metal
Finishing Wastewaters
Capsule Report: Sulfide Precipitation
for Metal Finishers
Plating Catalysts: A New Technology
for Pollution Abatement
Dialysis Purification of Metal Finishing
Rinsewater
Treatment of Wastewater from
Chromium Plating Line
Effects of Anions on the Precipitation
of Heavy Metal Ions
on Electroplating Wastewaters: Phase I
Control of Fluoroborates
from Electroplating Wastewater
Electrolytic Treatment of Oily
Wastewaters
Capsule Report: Evaporators for Metal
Finishers
Capsule Report: HSA Electrochemical
Reactor Results (Planned)
Evaluation of Hydroxide vs.
Sulfide Precipitation of Heavy Metals
Actual demo on conventional electroplating
wastewater system planned. Site for demo
currently being selected.
Manual designed for usage by consultants and
plant engineers for upgrading existing
conventional systems and designing new
systems. Applicable to all industries treating
acidic or alkaline metal-bearing Wastewaters
(metal finishing, nonferrous metals, inorganic
chemicals, etc.)
New filtration system being demonstrated on
acidic metal-bearing wastewaters for battery
manufacturing plants.
Skidmounted system utilizing evaporator and
best known membranes operating on high pH
(current) and low pH and oxidizing solutions
(planned).
Demo of Sulfex system on metal finishing
wastewaters. Final report in preparation.
Full color capsule report being prepared for
wide dissemination describing instability of
soluble and insoluble sulfide systems, capital
and operating costs, and sludge generation.
New plastics plating approach being developed.
Possible substitute for Palladium being
introduced.
Demonstration of Donnan Dialysis for
recovery of nickel from nickel plating
rinsewaters.
Demonstration of electrodialysis for recovery
of chromium from decorative chrome plating.
Determination of major interferences in
carrying-out conventional treatment.
Research to apply electrodialysis to recover
fluoroborate reagents from fluoroborate
plating rinsewaters.
New inexpensive technique developed for
removing oils from metal finishing wastewater.
Full color capsule report being prepared for
wide dissemination describing the application
of evaporators for wastewater control,
capital and operating costs, and energy aspects.
Full color capsule report being prepared for
wide dissemination describing results of HSA
demonstration, 3rd party evaluation, and other
areas of applicability.
Side-by-side bench scale comparison of
conventional and sulfide precipitation.
related costs, and sludge generation.
Ben Smith
(513)684-4491
Alfred B. Craig
(513)6844491
Charles H. Darvin
(513) 684-4491
Mary Stinson
(201)321-6683
Mary Stinson
(201)321-6683
Ben Smith
(513)684-4491
Mary Stinson
(201)321-6683
Mary Stinson
(201) 321-6683
Mary Stinson
(201)321-6683
Mary Stinson
(201) 321-6683
Mary Stinson
(201) 321-6683
Hugh Durham
(513) 684-4491
Mary Stinson
(201)321-6683
Ben Smith
(513)684-4491
Hugh Durham
(513)684-4491
Solid Waste Activities I
Centralized Treatment:
EPA/AES Solid Waste
Characterization Program (Planned)
Centralized Treatment for
the Tauton Silver Platers
Matrix of sludges from metal finishing Alfred B. Craig
processes will be collected. Variations of (513) 684-4491
Toxicant Extraction Procedure (TEP) will be
run on sludge samples. Field studies will be
run for comparison.
Feasibility study of centralized treatment by Mary Stinson
grouping of companies addressing technical and (201) 321-6683
administrative aspects.
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Title
Narrative
Project Officer I Number
Documentation of Federal Republic
of Germany's Approach to Centralized
Treatment
Capsule Report: Centralized Treatment
for Metal Finishers
Metal Finishing Research Program
on Centralized Treatment (Planned)
Cadmium Recovery from Metal
Finishing Sludges (Planned)
Demonstration of Sludge Segregation
and Metals Recovery (Planned)
Report detailing approach used by FRC on
variety of industrial liquid and solid wastes.
Full color capsule report being prepared for
wide dissemination to discuss FRG's approach
to centralized treatment (CT), CTs
applicability in LI. S., and description of
EPA's Metal Finishing Research Program
on C. T.
Full program to analyze a variety of locales for
C. T., detailed analysis of one locale for
demonstration of C. T., and development of
evaluation tools for determination of
applicability of C. T.
Cadmium sludges will be evaluated by
nonferrous smelter to determine cost effective
method for cadmium recovery from sludges.
Planned to be conducted with Polish institute
in Warsaw under PL 480 Program. Polish
metal finishing industry will prepare and
operate segregated collection site for metal
finishing sludges. Metal recovery techniques
will be developed.
Alfred B. Craig
(513)684-4491
Alfred B. Craig
(513)684-4491
Alfred B. Craig
(513) 684-4491
Mary Stinson
(201) 321-6683
George S. Thompson
(513) 684-4491
18
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Attachment II
Summary of Published Reports
For Metal Finishing and Fabrication
Research Program
Report No.
(NTIS No.)
Publication Title I General Subject Matter
12010 E1E 11/68
I20IOEIE3/7I
(PM 215-694)
12010 EIE 11/71
(PB 208-210)
12010 DRH 11/71
(PB 208-211)
EPA-R2-73-287
(PB 231-263)
EPA-R2-73-044
(PB 227-363)
EPA-660/2-73-033
(PB 240-722/A5)
A State-of-the-Art Review of Metal Finishing
Waste Treatment
Review of conventional treatment methods.
Intended to provide facts for the guidance
of the small plater in the selection of a waste
treatment process.
An Investigation of Techniques for Removal
of Chromium from Electroplating Wastes
Describes work which was conducted on the
removal of hetfavalent chromium from
plating rinsewaters employing various treat-
ment processes.
An Investigation of Techniques for Removal
of Cyanide from Electroplating Wastes
Describes work which was conducted on the
removal of cyanide wastes from plating rinse-
waters employing various treatment
processes.
Uttrathin Membranes for Treating Metal
Finishing Effluents by Reverse Osmosis
Seventeen different membranes evaluated
for the separation of heavy metal ions, acids
bases and cyanides from water. Preliminary
engineering considerations on the applica-
tion of reverse osmosis to the treatment and
recycle of rinsewaters from an acidic copper
sulfate plating bath are included.
Investigation of Treating Electroplaters'
Cyanide Waste by Electrodialysis
The experimental system used in this study
was a prototype of a commercial size clec-
trodialysis unit operated continuously under
conditions which simulated those of the
projected two-stage commercial system.
Chemical Treatment of Plating Wastes for
Removal of Heavy Metals
Chemical rinsing of electroplated parts and
batch chemical treatment of spent processing
solution is demonstrated as a practical
approach for pollution abatement at a small
captive metal finishing facility.
New Membranes for Reverse Osmosis
Treatment of Metal Finishing Effluents
A new membrane designated NS-1 was
evaluated for the reverse osmosis treatment
of both highly alkaline and acidic (non-
oxidizing) metal finishing rinse waters.
Preliminary engineering considerations indi-
cated its application in the treatment and
recycle of nickel and zinc cyanide electro-
plating rinse waters.
Report No.
(NTIS No.)
Publication Title I General Subject Matter
EPA-660/2-73-024
(PB 234-447)
EPA-660/2-73-023
(PB 231-835)
Treatment and Recovery of Fluoride Wastes
Report presents the development and success-
ful demonstration of laboratory and pilot-
scale fluoride treatment techniques for
selected aerospace and metal working indus-
try chemical processing solutions and rinse
waters resulting from titanium chemical
milling, titanium descaling and aluminum
deoxidizing operations.
Regeneration of Chromated Aluminum
Deoxidizers, Phase I
A regeneration process was conceived and
tested to reduce the frequency of discharging
spent chromated aluminum deoxidizers
which are used extensively to deoxidize
aluminum surfaces prior to anodizing, con-
version coatings, paint preparation, welding
and adhesive bonding. Results established
that regeneration is feasible, practical and
economical.
EPA-670/2-74-008
(PB 223-143)
EPA-670/2-74-042
(PB 234-476/AS)
Metallic Recovery of Wastewaters Utilizing
Cementation
Bench-scale experiments utilizing the "cemen-
tation" reaction (i.e., electrochemical reduc-
tion by contact with a metal of higher
oxidation potential) were performed for the
precipitation of copper and the reduction of
hexavalent chromium in industrial streams.
Wastewater Treatment and Reuse in a Metal
Finishing Job Shop
Describes the complete wastewater treatment
system at the S. K. Williams Co. job plating
facility. Five integrated waste treatment
systems, each for a specific type waste com-
pound are used to protect the rinse waters
from process solution drag-out.
Laboratory Study of Continuous Electro-
oxidation of Dilute Cyanide Wastes
An experimental study was carried out to
determine the feasibility of detoxifying dilute
cyanide plating wastes by electrooxidation.
Cyanide and plating metal concentrations
could be reduced to less than I ppm.
EPA-650/2-75-019a Source Assessment: Prioritization of Air
(PB 243-423/AS) Pollution from Industrial Surface Coating
Operations
Report summarizes the results of a program
to gather and analyze background informa-
tion and technical data to establish a data
base for the purpose of prioritizing atmos-
pheric emissions from industrial surface
coating operations, excluding automobile
and architectural painting.
EPA-670/2-74-059
(PB 235-588/AS)
19
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Report No.
(NTIS No.)
Publication Title/ General Subject Matter
Report No.
(NTIS No.)
Publication Title/General Subject Matter
EPA-670, 2-75-018
(PB 242-018/AS)
EPA-600/2-75-028
(PB 246-560/AS)
EPA-670/2-75-055
(PB 243-370/AS)
Reclamation of Metal Values from Metal
Finishing Waste Treatment Sludges
Report determines the worth of recovering
metal values from metal finishers waste-
water treatment sludges. The extraction of
metal values from waste sludges by various
leaching agents, and the recovery of the metal
values by various techniques such as electro-
winning, cementation, and liquid - liquid
ion exchange were investigated on a bench-
scale.
Electrolytic Treatment of Job Shop Metal
Finishing Wastewaters
Full scale in-plant production studies demon-
strated the reliability and economics of elec-
trolytic cells containing beds of conductive
particles between cathodes and anodes for
reduction of hexavalent chromium and
oxidation of cyanide in-plating rinse water.
Removal of Chromium from Plating Rinse
Water Using Activated Carbon
Activated carbon is highly effective in adsorb-
ing chromium from rinse water. Laboratory
and pilot-scale studies were conducted to
determine the effects of basic and acidic
media regeneration of chromium-loaded
activated carbon especially as it affects
adsorption capacity of the carbon after
repeated cycling.
EPA-600/2-76-197 New Membranes for Treating Metal Finish-
(PB 265-363/2BE) ing Effluents by Reverse Osmosis
Long-term reverse osmosis tests showed the
NS-IOO membrane (formerly NS-1) to be an
excellent membrane for potential indus-
trial use in the recycle of rinse water and
plating chemicals from acid copper and zinc
cyanide electroplating lines. Two experi-
mental NS-101 membranes demonstrated
twice the flux of the NS-IOO for alkaline
zinc cyanide (about 27 l/m2 hr, or 16 gfd).
EPA-600/2-76-261 Treatment of Electroplating Wastes by
(PB 265-393/9BE) Reverse Osmosis
Emphasis placed on closed-loop operation
with recycle of purified water for rinsing, and
return of the plating chemical concentrate
to the bath. Three membrane configurations
evaluated; tubular (cellulose acetate), spiral-
wound (cellulose acetate) and hollow-fiber
(polyamide). Test conducted on nine
different rinse waters.
EPA-600/2-76-296 Metal Removal and Cyanide Destruction
(PB 266-I38/7WP) in Plating Wastewaters Using Particle Bed
Electrodes
A small (0.5 gpm) electrolytic cell consisting
of a tin cathode and graphite anode particle
bed electrodes and cellophane separator
was tested on cadmium and zinc cyanide
rinse waters at a plating plant.
EPA-600/2-77-038 Zinc Sludge Recycling After Kastone*
(PB 266-929/9WP) Treatment of Cyanide Bearing Rinse Water
This report attempts to show the feasibility
of zinc metal recovery after oxidation of
cyanide by formaldehyde and Kastone®.
Included is a critique of the design of
necessary equipment and modifications of
the plating process needed to accommodate
the recovery.
EPA-670/2-77-039 Reverse Osmosis Field Test: Treatment of
(PB266-9I9/OWP) Watts Nickel Rinse Waters
Report presents results of field test data to
determine the feasibility of using a poly-
amide reverse-osmosis membrane in hollow
fiber configuration for closed-loop
treatment of rinse water from a Watts-type
nickel bath.
EPA-600/2-77-949 Treatment of Metal Finishing Wastes by
(PB 267-284/8WP) Sulfide Precipitation
Compares conventional lime treatment for
precipitating heavy metals present in metal
finishing wastes with the ferrous sulfide
addition (Sulfex*) process. Studies consisted
of jar and bench-scale tests.
EPA-600/2-77-072 Foam Rotation Treatment of Heavy Metals
(PB 267-549/4WP) and Fluoride Bearing Industrial Wastewaters
Laboratory-scale investigation of floe foam
separation techniques to remove toxic heavy
metals and fluorides from wastewaters pro-
duced at primary aluminum smelters,
secondary lead smelters and copper and
brass mills.
EPA-600/2-77-105
(PB 27I-OI4/AS)
FPA-600 2-77-104
(PB 271-015 AS)
EPA-600 2-77-099
(PB 271-298)
Ammonium Carbonate Leaching of Metal
Values from Water Treatment Sludges
Experimental studies concentrate on defining
an ammoniacal leaching practice that would
maximize the return of copper and nickel
values from metal-finishing sludges to the
leach solution while at the same time mini-
mizing the dissolution of chromium values.
O/one Treatment of Cyanide Bearing Wastes
A lull scale plant demonstration of a highly
automated o/onation system for the destruc-
tion of cyanide in electroplating wastewaters
and for the removal of copper and silver us
their oxides.
Inovative Rinse and Recovery System for
Metal Finishing Processes
Report described the feasibility of a non-
aqueous rinse and recovery system that can
be installed on a plating line. A chrome
plating bumper line was simulated lor test
purposes.
20
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Report No.
(NTIS No.)
Publication Title/General Subject Matter
Report No.
(NTIS) No.)
Publication Title/General Subject Matter
EPA-600/2-77-I6I
(PB 272-688)
EPA-600/ 2-77-170
(PB 272-473)
Electrodialysis for Closed Loop Control of
Cyanide Rinse Waters
Report evaluates a full-scale, closed-loop
electrodialysis system for brass plating
cyanide rinse waters. The system proved to be
inefficient and therefore unsuitable for this
application.
RO Field Tests: Treatment of Copper
Cyanide Rinse Water
Report describes results of RO Field tests on
copper cyanide rinse waters at Whyco
Chromium Co. and New England Plating
Co. At both sites, closed-loop treatment
was used with plating chemicals recycled
to the bath and purified water recycled to
the rinsing operation.
Regeneration of Chromated Aluminum
Deoxidizers - Improved Diaphragm
Fabrications, and Performance
A laminated ion-selective diaphragm was
developed during Phase 1 (EPA-660/2-73-
023) as a necessary part of the electrolytic
process. This report describes improved
diaphragm fabrication techniques and
performance.
EPA-600/2-78-048 Treatment of Fluoride and Nitrate Industrial
Wastes Phase II
This report is an extension of EPA-600/
2-78-024 laboratory and pilot-scale
techniques to treat selected chemical process-
ing solutions and rinse waters containing
fluorides and nitrates and the recovery of
usable byproducts are described. The
results of this study can be used to design a
production scale system.
EPA-600/2-77-194
(PB 272-687)
EPA-600/2-78-040
(PB 280-944/AS)
EPA-600/2-78-011
(PB 280-563/AS)
PBI Reverse Osmosis Membrane for
Chromium Plating Rinse Water
A laboratory scale research study to assess
the potential utility of poeybenzimidazole
(PBI) membranes in a reverse osmosis system
for the treatment of chromium plating rinse
waters. Study demonstrated PBI's chemical
stability to withstand long-term contact with
chromic acid waste streams.
Removal of Toxic Metals from Metal
Finishing Wastewaters by Solvent
Extraction
Laboratory-scale investigation to ascertain
the feasibility of utilizing solvent extraction
techniques to develop economical methods
for removing cadmium, chromium, copper,
nickel, and zinc ions from metal finishing
wastewater.
EPA-600/2-78-085
(PB 283-792/AS)
EPA-600/2-78-119
(PB 284-097/AS)
EPA-600/2-78-127
(PB 285-434/AS)
EPA-600/2-78-130
(PB 286-210/AS)
Removal of Heavy Metals from Industrial
Wastewaters Using Insoluble Starch
Xanthate
Report describes the preparation of an agri-
culturally based material and its use in heavy
metal cation removal from industrial waste-
waters. Insoluble starch xanthate (ISX) was
prepared and evaluated in wastewaters from
printed circuit industries, lead battery
companies, and a brass mill.
Evaporative Process for Treatment of
Phosphate Containing Effluent
Report describes the performance and
reliability of a pilot-scale evaporative
process for the treatment of dilute phosphate
containing effluent from an aluminum coil
cleaning operation at Alcoa's Warrick
County Indiana Plant.
Evaporative Recovery of Chromium Plating
Rinse Waters
Report describes the methodology and
determines the economics of a new evapora-
tive approach for recovering chromium from
metal finishing rinse waters in a typical
chrome job shop. Design centered around
Coming's PCR-60 vacuum climing-film
evaporator.
Aircraft Industry Wastewater Recycling
Report describes the feasibility of recycling
certain categories of water used in an airplane
factory. Based on the experiences of con-
structing and operating the pilot-scale
plant, an estimate was developed for the
cost of a full-scale water recycling plant.
EPA-670/2-75-029
(PB 241-822/AS)
EPA-670/2-75-015
(PB 241-793/AS)
Copper Recovery from Brass Mill Discharge
by Cementation with Scrap Iron
Report presents the results of studies of
copper recovery and incidental simultaneous
reduction of hexavalent chromium in a brass
mill discharge.
Pilot Plant Optimization of Phosphoric Acid
Recovery Process
Report describes the optimization and
economic evaluation of an acid regeneration
process which permits the recovery of phos-
phoric acid used in the bright finishing of
aluminum.
21
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ATTACHMENT
INDEX OF
RESEARCH PROGRAMS/CONTACTS
FOR
THE OFFICE OF ENERGY, MINERALS AND INDUSTRY
OFFICE OF RESEARCH AND DEVELOPMENT
DECEMBER 1978
USE OF THIS INDEX
This Index is meant to facilitate person-to-
person contact with the appropriate technical
individual within OEM! when assistance is de-
sired. The Index provides the Organizational
Charts of OEMI and lists research programs/
areas, persons to contact, their organizational
location and telephone number. The Index will
be updated periodically, as appropriate.
22
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OFFICE OF ENERGY, MINERALS & INDUSTRY
H1
Deputy Assistant Administrator:
Vacant (202) 7554857
Associate Deputy Assistant Administrator:
Dr. Steven Reznek (202) 7554858
l^^" "™™"™™ 1 1 ^^^^^1
PROGRAM OPERATIONS STAFF
Director: Merriln Merriman
H2 (202) 426-2507
ENERGY COORDINATION STAFF
Director: Clinton W. Hall
(202) 426-4567
H3
ENERGY PROCESSES DIVISION
Drector: Frank Princotta
(202) 755-0205
INDUSTRIALS EXTRACTIVE
PROCESSES DIVISION
Director: Carl Schafer
H5 (202) 755-9014
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATOR
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
Director Deputy Director
Dr. John Burchard Dr. Norbert Jaworski
629-2821 R1 629-2821
b
USTRIAL POWER
ION
tt Plyler
915
t Technology Branch
e Maxwell
•2578
nology Branch
hard Stern
•2915
chnology Branch
UBS Abbott
1-2925
Y
nPFirp n? P Finn RAM
OPERATIONS
Dr. John 0. Smith
R2 629-2921
-. • i « j- e. u Planning, Management, and
Special Stud,es Staff Adrninirtn.tkjn Staff
Or. W. Gene Tucker Mr. C. T. Ripberger (acting)
R3 629-2745 R4 629-2921
i
ENERGY ASSESSMENT AND CONTROL
DIVISION
Mr. Robert Hangebrauck
R9 629-2825
Combustion
Research Branch
Dr. Joshua Bowen
RIO 629-2470
Fuel Process Branch
Mr. T. Kelly Janes
R11 629-2851
Advanced Process Branch
Mr. P. P. Turner, Jr.
R12 629-2825
INDUSTRIAL PROCESSES
DIVISION
Mr. Alfred B. Craig
R13 629-2509
••
Chemical Processes Branch
Dr. Dale Denny
cm 629-2547
Process Measurements Branch
Mr. James Dorsey
R15 629-2557
Metallurgical Processes Branch
Mr. Norman Piaks
R16 629-2733
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATOR
5555 RIDGE AVE., CINCINNATI, OHIO 45268
Director Deputy Director
Dr. David G. Stephan Mr. William A. Cawley
C1 (513)6844402 6844338
1 =
- 1
Resource Extraction
and Handling Division
Mr. Ronald D. Hill
C3 684-4410
Oils and Hazardous
Materials Spills Branch
Mr. Ira Wilder*
C4 340-6635
Extraction Technology
, Branch
Mr. Eugene F. Harris
C5 684-4417
dustrial Environmental Research Laboratory,
ison.NJ 08817
mm
Y
OFFICE
Mr. Clyde J. Dial
1 ,
Industrial Pollution
Control Division
Or. Eugene E. Berfcau
C6 684-4314
Metals and Inorganic
Chemicals Branch
Mr. George S. Thompson, Jr.
C7 684-4491
Organic Chemicals and
Products Branch
Dr. Irvin A. Jefcoat
C8 684-4481
Food and Wood
Products Branch
Dr. H. Kirk Willard
C9 6844227
Energy Systems Environmental
Control Division
Mr. Alden G. Christiansen
CIO 684-4207
mm
mm
Power Technology and
Conservation Branch
Dr. Harry E. Bostian
C11 684-4318
Fuels Technology
Branch
Mr. George L. Huffman
C12 684-4478
23
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INDEX OF RESEARCH PROGRAMS/CONTACTS
FOR
THE OFFICE OF ENERGY, MINERALS AND INDUSTRY
Organi-
zational
Program Contact Location Phone
Adhesives and Sealants Ron Turner C8 684-4481
Advanced Energy Conversion Bill Cain C11 684-4335
(eg. Fuel Cells, MHD, High Temp. Gas Turbines)
Analytical Procedures — Oil and Hazardous Spills Mike Gruenfeld C4 340-6625
Asbestos Manufacturing Mary Stinson C7 340-6683
Boilers — Utility/Industrial
By-Product Marketing Chuck Chatlynne R7 629-2915
Effects/Assessment Wade Ponder R7 629-2915
Fluidized Bed Combustion Bruce Henschel R12 629-2825
NOx Control (By Combustion Modification) Josh Bowen R10 629-2470
(By Flue Gas Treatment) David Mobley R7 629-2915
Paniculate Control James Abbott R8 629-2925
SO, Control (Non-Regenerable) Mike Maxwell R6 629-2578
(Regenerate) Dick Stern R7 629-2915
Thermal Effects Control Ted Brna R6 629-2683
Waste Disposal Julian Jones R6 629-2489
Water Pollution Julian Jones R6 629-2489
Brick Kilns Chuck Darvin C7 684-4491
Chemical and Fertilizer Minerals Mining Jack Hubbard C5 684-4417
Clay, Ceramics and Refractories Mining Jack Hubbard C5 684-4417
Clay, Ceramics and Refractories Processing Chuck Darvin C7 684-4491
Coal Cleaning Plants Jim Kilgroe R11 629-2851
Coal Processing
Coal Mining John Martin C5 684-4417
Coal Cleaning Jim Kilgroe R11 629-2851
Coal Storage John Martin C5 684-4417
Gasification Bill Rhodes R11 629-2851
Insitu Gasification
Underground Aspects Ed Bates C5 684-4417
Aboveground Aspects Bob Thrunau C12 684-4363
Liquefaction Bill Rhodes R11 629-2851
Combustion Modifications Josh Bowen R10 629-2470
Compounding and Fabricating Industries Ron Turner C8 684-4481
(e.g. Furniture, Printed Products, Transportation Equipment)
Construction Materials Mining Jack Hubbard C5 684-4417
Electroplating Chuck Darvin C7 684-4491
Energy Management (Conservation) Bob Mournighan C11 684-4335
Ferrous Metallurgy Norm Plaks R15 629-2733
Fertilizer Manufacturing Dale Denny R14 629-2547
Food Products Ken Dostal C9 684-4227
Fugitive Emissions Control
(Call Appropriate Industry Contact)
Furnaces — Residential/Commercial Josh Bowen R10 629-2470
Gas Turbines/IC Engines Josh Bowen R10 629-2470
Geothermal Energy Bob Hartley C11 684-4334
Glass Manufacturing Chuck Darvin C7 684-4491
Hazardous Matrial Spills Frank Freestone C4 340-6632
Indoor Air Quality Bill Cain C11 684-4335
Industrial Laundries Chuck Darvin C7 684-4491
Inorganic Chemicals Chuck Darvin C7 684-4491
Iron and Steel Foundries Norm Plaks R15 629-2733
Lead Storage Battery Industry Chuck Darvin C7 684-4491
Lime/Limestone Scrubbing (Power Plants) Mike Maxwell R6 629-2578
Machinery Producing Industries Chuck Darvin C7 684-4491
Measurements for Stationary Sources
General jjm Dorsey R16 629-2557
Organic Analysis Larry Johnson R16 629-2557
Inorganic Analysis Frank Briden R16 629-2557
Particulate Samples Bruce Harris R16 629-2557
Instrumentation Bill Kuykendal R16 629-2557
24
-------
Metal Finishing and Fabrication Chuck Darvin C7 684-4491
Mine Drainage (Treatment) Roger Wilmoth C5 684-4417
Nonferrous Metals John Burckle C7 684-4491
Nonferrous Metal Mining Jack Hubbard C5 684-4417
Oil and Gas Production Ira Wilder C4 340-6635
Oil Processing
Petrochemicals Dale Denny R14 629-2547
Refineries Dale Denny R14 629-2547
Residual Oil Sam Rakes R12 629-2825
Oil Shale
Mining and Shale Handling/Disposal Ed Bates C5 684-4417
Retorting (Surface and Insitu) George Huffman C12 684-4478
Insitu Environmental Impacts Ed Bates C5 684-4417
Oil Spills Ira Wilder C4 340-6635
Organic and Specialty Chemicals Atly Jefcoat C8 684-4481
Paint and ink Formulating Ron Turner C8 684-4481
Particle Control
Control Devices
Electrostatic Precipitator Lee Sparks R8 629-2925
Fabric Filters Jim Turner R8 629-2925
Scrubbers Dennis Drehmel R8 629-2925
From Specific Sources (call Appropriate Industry Contact)
Paving and Roofing Materials Manufacturing Ron Turner C8 684-4481
Pesticides Manufacturing Dale Denny R14 629-2547
Petrochemicals Manufacturing Dale Denny R14 629-2547
Petroleum Refineries Dale Denny R14 629-2547
Photographic Processing Ron Turner C8 684-4481
Pulp. Paper and Wood Mike Strutz C9 684-4227
Smelters John Burckle C7 684-4491
Soaps and Detergents Ron Turner C8 684-4481
Steel Making Norm Plaks R15 629-2733
Solar Energy C.C. Lee Cl 1 684-4335
Surfactants Manufacturing Ron Turner C8 684-4481
Synthetic Fuels from Coal (in Situ) Bob Thurnau C12 684-4363
Synthetic Fuels from Noncoal Sources Tom Powers C12 684-4363
Synthetic Fuel Production
Coal Gasification
Surface Bill Rhodes R11 629-2851
Insitu
Underground Aspects Ed Bates C5 684-4417
Aboveground Aspects Bob Thurnau C12 684-4363
Coal Liquefaction Bill Rhodes R11 629-2851
Non-Coal Based George Huffman C12 684-4478
Textile Manufacturing Dale Denny R14 629-2547
Toxic Chemical Incineration
At Sea Ron Venezia R14 629-2547
Hazardous Materials Spills Related Ira Wilder C4 340-6635
Specific Sources (call Appropriate Industry Contact)
Transportation — Equipment Producing Industries Chuck Darvin C7 684-4491
Transportation — Solid Fuels John Martin C5 684-4417
Uranium Mining Jack Hubbard C5 684-4417
Waste as Fuel
Co-Firing and Polution Control Bob Olexsey C12 684-4363
Pollutant Characterization Harry Freeman C12 684-4363
Pyrolysis Wally Liberick C12 684-4363
For further assistance on IERL-RTP programs you may contact: ... C. T. Ripberger R4 629-2911
For further assistance on IERL-CINTI programs you may contact:.. Clyde Dial C2 684-4247
Note: for all "684" exchanges, use area code "513"; for all "340 exchanges, use area code "201"; for all "629" exchanges, use area
code "9I9."
25
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Metal Finishing Sludge Disposal;
Economic, Legislative and
Technical Considerations For 1979
Myron E. Browning, John Kraljic & Gary S. Santini*
The metal finishing industry generates large amounts
of sludge. Estimates reveal that by I983 the U. S.
electroplating and surface finishing industry will generate
over 1.5 million tons (dry weight) of sludge. At the
present time, very limited quantities of sludge are being
processed for value recovery or secondary use. Research
and development work is under way to reduce the volume
of sludge, to lessen the burden of disposal and ultimately
to recover valuable natural resources. At the Federal and
State levels, regulations to control the generation and
disposal of sludges are nearing completion. Many of the
questions as to the management of metal finishing waste
are still unanswered and some will be addressed during
this conference. This presentation will give a brief
overview of legislative, economic and technical aspects of
sludge disposal.
Considerable progress has been made in regulatory
programs at the Federal and State levels to control the
disposal of solid wastes. The Federal Solid Waste
Disposal Act of 1965 (I) was primarily an authorization
for research and development. The purpose of its
amendment, the Resource Recovery Act of 1970 (2) was
to provide financial assistance to State and local
governments for the construction of solid waste disposal
facilities, and also to promote research and development.
The Act also recommended thai guidelines for solid
waste disposal, collection and recovery be published in
the Federal Register. The guidelines (3) were finally
published on August I4, 1974. The guidelines are
mandatory only to Federal agencies and apply I) to all
solid waste generated by Federal agencies and 2) to solid
wastes generated by non-Federal entities but processed
or disposed on Federal property. They do not apply to
hazardous waste disposal.
The Resource Conservation and Recovery Act of 1976
(RCRA) (4) not only amended the Solid Waste Disposal
Act of 1970 but it greatly expanded the Federal role in the
solid waste and resource recovery field. The law requires
that EPA develop guidelines to assist state and local
governments in solid waste management and approve the
'Myron E. Browning. John Kraljic & Gary S. Santini
Allied Chemical Corporation, Industrial Chemicals Div.
state plans for handling of solid waste. A major part of
the law is concerned with management of solid waste as it
relates to generation, transportation and disposal
facilities. EPA is also required to identify what
constitutes a hazardous material and provide methods of
disposal. Recently the EPA issued the proposed
hazardous waste guidelines and regulations covering I)
identification and listing of hazardous waste, 2)
standards for generators of waste and 3) standards
applicable to management of hazardous waste facilities
(5). Hearings on the proposed guidelines and regulations
are scheduled for February and March 1979.
Most states have some rules and regulations for
hazardous waste disposal. Some states are busy working
on laws to control waste disposal while others have the
regulations and experience that EPA is using in
implementing the mandate of the Resource and Recovery
Act. One of the major problems facing the states in this
area is the location of acceptable new sites for solid waste
disposal.
The State of New York now has two certified
hazardous waste receiving landfills and both of these are
located in the Buffalo area. The work is in progress to
approve a third site before the RCRA regulations are
promulgated (6). Costs of having sludge shipped to this
western area will create an increasing economic problem
with the metal finishers in this state.
In the State of Ohio, disposal of hazardous waste on
some 10 or 12 landfills is controlled by state law (7).
Sludges are buried separately in geologically secure (clay
base) area of the landfill; no manifest is currently
required for dumping. It is proposed that metal
hydroxide sludge delivered for permanent storage be
dewatered to no less than 30 percent solid, excluding
water of hydration.
The State of Illinois has three divisions of state
government involved in solid waste management: I) the
Illinois Institute for Environmental Quality (I1EQ), 2)
the Illinois Environmental Protection Agency and 3) the
Illinois Pollution Control Agency. The Illinois Institute
for Environmental Quality studies the effects and new
problems in solid waste. The Illinois Environmental
Protection Agency sets the regulations while the Illinois
Pollution Control Agency enforces them (8). Metal
26
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finishing wastes come under the law which permits a
maximum of 200 ppm of any heavy metal and a
maximum of 50 ppm of cyanide to be discharged. Illinois
has some 64 approved landfills: 24 in the northern sector,
16 in the central region and 24 in the sourthern area of the
state. Special Waste Disposal Permits (GREEN) are
presently the documents used to control and monitor the
waste being landfilled.
California has perhaps one of the most advanced
systems for the disposal of solid waste by any of the high
metal finishing industry states. Sites for waste disposal
are classified as I, 2 or 3, depending on material being
handled. The class 1 sites, 10 of which reportedly are
approved around the state, can only receive hazardous
waste materials that includes the metal finishing wastes.
The hauler must be registered with the state while the
generator of waste must provide a manifest identifying
the material and the concentration of each compoenent
in the sludge being disposed (9).
Metallic hydroxide sludges which constitute part of the
solid waste disposal problem, are generally the product of
a chemical or electrochemical treatment of waste
streams. For a plating shop doing copper, nickel and
chromium plating, the equipment needed to process the
waste effluents could include: cyanide destruct, chrome
destruct, pH adjustments, clarification and sludge
dewatering. The reported capital cost of purchased
equipment is as follows:
1. Cyanide Destruct
The cost of a continuous treatment system for cyanides
with all of the automatic features such as automatic pH
meters, ORP probes, chemical feed pumps, liquid level
controllers and alarms, the required tanks and piping for
flow rates of 1000 gallons per hour and 2000 gallons per
hour has been reported as $47,808 and $55,566 (10).
2. Chrome Destruct
The cost of a continuous treatment system for chromium
with all the required automatic features and capable of
handline flows of 1000, 2000, and 5000 gallons per hour
has been reported as $20,416, $21,538 and $24,003
respectively (10).
3. pH Adjustment
The pH adjustment costs for flow rates of 130, 1,300 and
13,000 gallons per hour have been given as $ 1,452, $4,921
and $18,855 respectively (9).
4. Clarification
The cost of clarification equipment capable of handling
flow rates 10,000, 20,000 and about 41,000 gallons per
hour has been given as $71,363, $91,575 and $130,102
(10).
5. Other Costs
Among the additional costs can be listed: installation
costs, the cost of sludge dewatering and spill control
facilities.
The installation costs are about 50 percent of the
investment cost (11).
Sludge dewatering equipment adds 10 to 30 percent
investment costs (II). The cost of spill control
containment facilities will range from 10 to 20 percent of
the total capital investment (II).
For a system operating 16 hours per day (4,000 hours
per year) and a flow of 50 gallons per minute for a stream
containing:
Copper = 45 mg/1 (I.I Ib/hr)
Nickel = 75 mg/1 (1.9 Ib/hr)
Chrome = 100 mg/1 (2.5 Ib/hr)
Cyanide = 30 mg/1 (0.75 Ib/hr)
The operating cost would be (12):
= 0.75 lb/hrX$3.25/lb =
= 2.5 Ib/hr X$0.60/lb:
Cyanide
treatment
Chrome
reduction
Copper
precipitation =0.5 Ib/hr X $0.10/lb =
Nickel
precipitation =0.5 Ib/hr X $0.10/lb =
Chrome
precipitation =2.5 Ib/hr X $0.10/lb =
Labor = 2 hr/day at $10.00/hr =
Utilities = 10 HP and water =
Sludge disposal = 6 GPH X $0.40/gal =
$2.44/ hr
$l.50/hr
$0.05 hr
$0.19/hr
$0.25/hr
$1.25/hr
$0.30/hr
$2.40/hr
Total = $8.38/hr
Yearly cost = $33,520
Another example of waste water treatment is an
electrochemical treatment of cooling water blowdown
containing chrome and zinc. The installed cost of a
building to house the unit plus auxiliary equipment
which includes surge tank, lamella clarifier, centrifuge,
sand filters and interconnecting piping was
approximately $398,000 (13). The Electrochemical
Chromate Removal System-Process Diagram is shown
below.
Electrochemical Chromate Removal System-Process
Diagram
LamelaQantter
Electrochemical
Treatment System
This system is capable of treating up to 600 gallons per
minute of cooling tower blowdown containing 20 ppm
chromate and 3 ppm zinc. The operating costs per day for
27
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a total flow of 428 gpm at a chromate concentration of 18
ppm is as follows:
Normal operating labor = $30.00
Electrode change labor = $ 2.00
Electrode consumption =$58.13
Power consumption = $ 2.23
Total operating cost = $92.36 per day
The overall reaction of this system is:
0.5 Cr2O7 + 3 Fe (OH)2 + 3.5 H2O
- Cr(OH)3 + 3 Fe(OH)3 + OH"
Based on stoichiometry, 3.22 pounds of iron are
required to reduce 1 pound of hexavalent chromium. In
actual operation 2826 pounds of iron were consumed and
664 pounds of Cr"1 reduced, giving a ration of 4.25
pounds of iron per pound of Cr* reduced. At the
electrode cost of $0.3306 per pound, the cost per day for
the electrode was $58.13.
Based on the volt and amperes for each cell, 4.8 kwh
were consumed for each pound of Cr*6 treated. For
electrical cost of $0.0112 per kwh and 41.52 pounds of
Cr"1 treated, the cost per day for power was $2.23.
Operating labor was about 3 hours/ day and at a rate of
$10 per hour, the cost equated $30 per day.
The system produced about 50 gallons of sludge per
day. A contractor removed the sludge to a landfill at 30
cents per gallon or $15 per day.
Sludge Disposal
Public and private landfills are mostly used for sludge
disposal. These findings are based on a survey of 600
plating shops. One hundred and fifty companies
responded to the questionnaire with 88 of them
answering the sludge-related questions. The data are
shown in the following table.
Table 1
Sludge Disposal Survey (14)
Sludge Disposal
Public landfill or dump
Private landfill or dump
Sell for reclamation
Pay to haul away
Number of Companies (88)
32
45
8
3
Lagooning has been one of the on-site methods of
disposal of metallic hydroxide sludges. There is not much
data available as to the effect of this method of disposal
on ground water. One may cite, however, one example
(14) when a sludge lagoon has been in operation for 10
years and the core borings have shown no measured
metal enrichment just a few inches below the sludge layer.
These findings, resultant of work done on an EPA
contract, could be expected as metallic hydroxide sludges
are hard to filter and will rapidly plug any porosity in the
soil (14).
Indiscriminate disposal of sludges on municipal
landfill also cannot be recommended. Metallic sludges
mixed with garbage and organic waste are likely to go
back into solution as organic acids are formed through
anaerobic decomposition of the organic waste.
It is preferable to segregate the waste and dispose of it
in an environmentally safe manner. This practice will
minimize potentially toxic elements in the waste from
going back into solution. If any problem should arise,
the source of the problem can be readily identified and
corrective action taken. If it ever becomes economically
attractive to recover metal values from a specific type of
waste, the location of that waste will be known and it can
be readily collected.
Large quantities of metallic hydroxide sludges are
being produced. An estimte of heavy metals (copper,
nickel, chromium and zinc) in sludge produced in Grand
Rapids in 1972-73 and in Waterbury in 1974 has been
placed at 1,500,000 Ibs and 700,000 Ibs respectively. A
more recent estimate of total sludge produced from
electroplating operations in the U. S. gives the following
tons (dry weight) (15):
1974 - 830,000
1973 - 1,200,000
1983 - 1,600,000
Some large metal finishing plants have been reported
as spending over $50,000 a year for hauling away sludge
valued at about $200,000 (14). It may not be surprising,
therefore to learn that a number of schemes have been
advanced to recover metal values from metal finishing
sludges.
The main problem with metal recovery has been the
composition of the sludges. Metals most commonly
found in sludge are: copper, nickel, chromium, zinc,
cadmium and tin. As indicated in the following table,
sludges from various plating lines are not kept separate.
Combination of
Number of Metals
\
2
3
4
5
6
7
Table 2
Metals Found In Sludge (14)
Percent of Total
(113 Plants)
11.5
16.8
20.4
18.6
8.0
IS.O
9.7
According to these data, almost 90 percent of metallic
sludges contain two or more elements. The complexity of
metallic separation and recovery appears to be related to
the number of metals as well as to the type of metal
present in the sludge. Segregated sludges can be
considered as ready for shipment to a refinery or to a
disposal plant. Sludges containing copper plus nickel do
not seem to offer great problems in separation. When
zinc and/or chromium, however, are present in mixed
metallic hydroxide sludges, the separation is neither
28
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Cu
«•
M
at
Fig. 1—Recovery of Cu, Nl, Cr, Fe from Mixed Sludge (14).
simple nor economical. A simplified process flow sheet
for separation of Cr, Ni, Cu and Fe from a mixed
hydroxide sludge can be used to illustrate this point. (See
Figure I).
A more promising way to separate copper and nickel
from trivalent chromium is to treat the sludge with
ammonium carbonate. In this approach, nickel and
copper are extracted while trivalent chromium is left in
the residue (14). The cost of ammonium carbonate
treatment is considerably higher than that of the sulfuric
acid route. Operating costs for a plant processing five
tons of sludge per day (dry basis) were estimated at $ 1,740
per day. The value of recovered metals was placed at $640
per day giving a cost deficit of $1,090 per day (14).
Another concept for recovery of metal values from
sludges proposed the following scheme (16):
I. Conversion of dried sludge to chlorides.
2. Separation of metal chlorides by vapor pressure
differences.
3. Electrowinning of metals and alloys from a molten
chloride bath.
In another process Cr and Fe were extracted and
separated fromCu, Ni and Zn by treating the sludge with
oxalic acid at pH of 1 to 2. Fe and Cr were precipitated as
hydroxides at pH of 9 to 10 and >ll respectively.
Insoluble salts such as copper, nickel and zinc oxalates at
pH of II to 12 change to the hydroxides. Oxalic acid was
recovered and recirculated (17). It is claimed that 98
percent of chromium was recovered (18).
In another scheme, ozone was used to separate and
recover chromium from mixed sludge (19). Moist sludge
was made alkaline with lime and the suspension treated
with ozone until trivalent chromium was oxidized to the
hexavalent form. The soluble CaCrCh was then filtered
out and separated from the residue.
Nickel has been recovered from sludge formed as
nickel sulfate rinses are treated with sodium bicarbonate.
Insoluble nickel carbonate precipitate is dewatered by a
filter press to 50 percent solids and the dry filter cake
shipped to a processing center where it is converted to
nickel sulfate plating solution (20). The capital cost to a
plating shop involves the purchase of equipment to
precipitate and produce a 50 percent solids nickel
carbonate sludge. The cost is about $40,000 and the credit
that a plating shop owner gets averages 50 percent of the
purchase price of new nickel sulfate baths (20).
Recycling of the zinc sludge from cyanide zinc plating
has also been reported (21). After adjusting the pH of
rinse water to 10.5, proprietary solution was added to
treat the cyanide and precipitate zinc as metal oxide. The
precipitate after filtration has the solid content of 40 to 50
percent and is returned to the plating tank.
Researchers at the Bureau of Mines (22) have
demonstrated that waste phosphate sludges formed
during treatment of ferrous surfaces with phosphating
solution can be treated to yield trisodium phosphate, zinc
and a low-phosphorus ferronickel powder which can be
recycled to a steel furnace. Phosphates and metal values
were also obtained from phosphate sludge by solvent
extraction (23). The sludge was first dissolved in
hydrochloric acid. Iron and zinc were extracted with
appropriate solvents and trisodium phosphate recovered
by crystallization. The value of marketable products was
reported as considerably more than the main reagent
costs.
Sludges can be disposed of in a potentially
environmentally accepted manner by such techniques as
heat treatment and chemical fixation or they might be
utilized in the manufacture of various products.
Separation of heavy metals in water by an insoluble
cross-linked xanthate compound derived from starch
is moving out of the laboratory stage. At an estimated
cost to manufacture starch xanthate at 20 to 22 cents per
pound (24), the initial cost estimates indicate a potential
reduction in waste water treatment cost. Even though the
metals are said to be reclaimable from starch-xanthate,
the starch metal couples may also have to be disposed as a
sludge. As the sludge is probably not suited for land
disposal as its organic structure is expected to break
down and release the metal to the environment, a recently
announced sludge recycling technique developed for
tannery chromium sludge might work with starch-
xanthate sludge. The catalytic molten salt incineration
process oxidizes organics in the sludge at temperatures
below 1000° F and yields chromium ash. Molten salt
incineration system is reported capable of handling 3000
pounds of sludge per hour at an estimated cost of $30 per
ton (25).
A batch chemical destruct system, utilizing highly
efficient mixing, produces a more granular and less
voluminous sludge than the usual hydroxide waste. X-
ray diffraction studies of the sludge reportedly reveal a
molecular structure less prone to leaching (26).
High temperature heat treatment of sludges at
temperature where the metal hydroxides are converted to
metal oxides would reduce the volume of the sludge,
reduce its solubility and thus reduce the potential of
redissolution. The solubility of heat treated plating
sludges as a function of temperature is given in Figure 2
(27).
According to the data presented in Figure 2,
chemically stable, water insoluble substance is produced
at 1100 to 1200° C.
Heat treatment of sludges containing chromium has to
29
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200 300 400 500 600 700 800 900 1000 1100 1200 1300
TEMPERATURE. C
Fig. 2—Water Solubility of a Heat Treated Plating Sludge (27).
be carried out under controlled conditions. If chromium
containing sludge is heated above 200° C (392° F) in the
presence of alkalies, some of the trivalent chromium is
oxidized to the hexavalent form (14, 28). Sludge dried at
200° C (400° F) to 230° C (450° F) in multiple-hearth
furnace produced sintered metallic oxides (29).
Some disposal technologies are reportedly
environmentally adequate while others utilize the sludge
in the manufacture of various products. Among these are
listed: 1) land reclamation, and 2) low grade cement.
According to one process (30), sludge mixed with proper
liquid and solid reagents forms a solid, inert and
insoluble material suitable for land reclamation. The
stability and chemical properties of the product are given
in Table 3 (31):
Ford Motor Company's plant at Lorain, Ohio, has
been reported as having used the process on its lagooned
metallic hydroxide sludges (32).
More than 70,000,000 gallons of various wastes have
been treated. Indications are that the grass grown on
chemically fixed waste waste containing high
concentration of toxic metals does not take up any
abnormal metal concentration.
Another potentially beneficial property of chemically
fixed waste is said to be in the ability of the solidified
material to remove toxic substances from solutions (33).
According to a recent investigation (34), sludges
containing hydroxides of nickel, chromium, zinc,
cadmium, copper and aluminum have been found
suitable as additives to low grade cement mortars and
concrete. Typical applications for the sludge-containing
cement mortars has been in the fabrication of flagstones,
fences, tiles and road foundations. On a dry basis, the
recommended sludge concentration in cement is listed as
between 2 and 5 percent. Those cements have improved
corrosion resistance and sludge metals cannot readily
leach out to contaminate the waters (34).
While research studies suggest these as suitable, the
segregation and inventorying procedures mentioned
earlier are being recommended more today.
Fluoride containing solutions are used in deoxidizing
of aluminum, descaling or pickling of titanium and
stainless steel, chemical milling of titanium and in
conversion coatings formulations. One of the treatment
methods for disposing of fluoride containing solutions is
based on lime precipitation. The lime treatment produces
calcium fluoride sludge which is disposed as a landfill. As
there are some questions raised as to the solubility of
calcium fluoride and its eventual leakage into waterways,
tests were conducted to establish whether calcium
fluoride sludge could be added to concrete. The tests
conducted on concrete containing calcium fluoride
sludge showed that compression strength of concrete
containing 6.8 percent CaFj sludge is higher than that of
the standard concrete mixture; the flexural strength was
equivalent to that for standard concrete. A teachability
test showed an insignificant amount of fluoride leaching
out of concrete (35).
Landfill disposal is still the most common practice
in the plating industry and it will probably be so long as
the recovery processes prove to be uneconomical.
Segregation of waste streams and sludges, however,
could make recovery and other applications for sludges
more attractive.
REFERENCES
1. The Solid Waste Disposal Act, Title II, Public Law
89-272, October 20, 1965.
2. The Resource Recovery Act, Public Law 91-512,
October 26, 1970.
Wastr
Untreated Metal
Finishing Waste
Chemfix Metal
Finishing Waste
Table 3 (31)
PROPERTIES OF TREATED AND UNTREATED SLUDGE
Leachate Analysis, ppm
pH Solids Color Iron Chromium Nickel Copper Zinc
1-9 30,134 - 8,400 210 160 2,700 21.9
8.0 300 <5 0.15 0 0.20 0.29 0.15
30
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3. Environmental Protection Agency (EPA), Federal
Register, Vol. 39, Number 158, Part III, August 14,
1974.
4. The Resource Conservation and Recovery Act of
1976, Public Law 94-580 (Oct. 21, 1976).
5. Environmental Protection Agency (EPA), Federal
Register, Vol. 43, No. 243, December 18, 1978.
6. New York State Environmental Conservation Law,
Article 27, Title 9, Industrial Hazardous Waste
Management (in effect prior to January 1,1979); also
discussion with Frank Clark's office staff.
7. State of Ohio, Solid Waste Disposal Act, Ohio
Administrative Code 3745 (in effect prior to January
1, 1979); also discussions with the staff in the
Hazardous Waste Department, Richard Moffa's
office.
8. State of Illinois, Pollution Control Act, Chapter 7,
"Solid Wastes" (effective July 27, 1973); also
discussion with Paul Bartholomew of Scott Miller's
office.
9. State of California, Legislative Bill A B-1593,
amended in 1977 and in effect prior to January 1,
1979; also discussions with personnel in Dr. Harvey
Collins, Hazardous Materials Management Depart-
ment.
10. "Development Document for Proposed Existing
Source Pre-Treatment Standards for the Electro-
plating Point Source Category," EPA440/1-78/085,
February 1978.
II. "Comments by the National Association of Metal
Finishers on the Pretreatment Standards for the
Metal Finishing Proposed by EPA on February 14,
1978," NAMF, August 30, 1978.
12. D. W. Mink, "Chemical Treatment of Plating
Waste," Pollution Abatement Seminar, (MFSA),
Framingham, MA, April 27, 1976.
13. J. H. Haggenmacher and S. G. Gale, "Electro-
chemical Treatment of Cooling Water Slowdown,"
International Water Conference, Pittsburgh, PA,
November 2, 1977.
14. A. B. Tripler, et. al., "The Reclamation of Metal
Values from Metal Finishing Waste Treatment
Sludges," Project 12010 FXD, Sponsored by Metal
Finishers' Foundation and U. S. Environmental
Protection Agency. EPA 670/2-75-018, April 1975.
15. E. B. Easton, "Metal Finishing Industry Sludge:
Victim or Villain?' Sludge, Jan. - Feb., 1978, p. 26-
16. D. D. Snyder, et. al., "Electrochemical Recovery of
Chromium from Industrial Waste," Research
Publication GMR-2080, Feb. 1976.
17. Yoshida Toru, "Treatment of Electroplating Mixed
Sludge," Kagaku Kojo 1977, 21 (2), 69-70.
18. Japan Chemical Week, August 4, 1977.
19. F. Drkos and V. Bahensky, Czech Pat. No. 130,794,
January 15, 1969 (C. A. 72:45599).
20. E. P. Grumpier, Jr., "Management of Metal
Finishing Sludge," EPA/530/SW-56I, February
1977.
21. Anon, "EPA Grant Helps Determine the Feasibility
of Recycling Cyanide Zinc Plating Sludge,"
Industrial Finishing, February 1976.
22. R. F. Waters, et. al., "Recovery of Metals and
Phosphates from Waste Phosphate Sludges," Metal
Finishing, 69, 39-42, (August 1972).
23. H. E. Powell, et. al., "Recovery of Phosphates
and Metals from Phosphate Sludge by Solvent
Extraction," U. S. Nat. Tech. Inform. Serv., PB
Report, 1972, No. 211933, 17 pp. Avail. NTIS(C. A.
78:61947).
24. "Water-Insoluble Starch Xanthate; Preparation and
Use in Heavy Metal Recovery," CA-NRRL-41
(Rev.) Peoria, IL, U. S. Department of Agriculture,
Agricultural Research Service, Northern Regional
Research Laboratory, August 1974, 5 p.
25. R. Dawson, "Leather Tanning Industry Sludge
Problems Ahead," Sludge Magazine, Sept. Oct.
1978, p. 24-27.
26. Anon, "Pollution Control Process for Heavy Metals
in Plating Rinse Waters," Products Finishing, 41, pp.
92-93 (August 1977).
27. R. Braun, "Problems in the Removal of Inorganic
Industrial Slurries. In Wastes: Solids, Liquids and
Gases!" ALCHEMA Symposium, 1970, Frankfurt,
New York Chemical Publishing Co., Inc., 1974, p.
203.
28. V. V. Bahensky and E. Kubanova, "Chromate
Formation in Effluent Sludges," Galvanotechnik 65
(1974), 10,5,856/857
29. Anon, "Products Finishing," Dec. 1974, p. 64.
30. J. R. Connor, "U. S. Pat. 3,837,872 (Sept. 26, 1974).
31. D. Krofchak, "Management and Engineering Guide
to Economic Pollution Control," Clinton Industries,
Inc., Warren, Michigan 48092 (1972).
32. Anon, "Ford Tests Sludge Solidification," Products
Finishing, 36, 55-57, (Jan. 1972).
33. J. R. Connor, "Ultimate Disposal of Liquid Wastes
by Chemical Fixation," Presented at the 29th Annual
Purdue Industrial Waste Conference, Purdue
University, West Lafayette, Indiana, May 7, 1974.
34. F. Tuznikand M. Kieozlowski,"Preliminary Studies
on complete Neutralization and Utilization of
Sludge from Plating Effluent Treatment Processes,"
Electroplating and Metal Finishing, 25,10-11,13-17,
(July 1972).
35. C. J. Staebler, Jr., "Treatment and Recovery of
Fluoride in Nitrate Industrial Wastes," Management
and Disposal of Residues from the Treatment of
Industrial Wastewaters; Information Transfer, Inc.,
Rockville, Maryland 20852 (1975).
31
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The Status of the EPA/AES Solid Waste Program
Kenneth R. Coulter*
The first conference on advanced pollution control for
the metal finishing industry was designed in part to
develop dialogue between industry and various sections
of EPA. This dialogue very clearly pinpointed several
problem areas and one of the most serious of these was
the disposal of sludges generated from the chemical
treatment processes designed for removal of heavy metals
from plating effluents.
One of the conclusions of the conference as quoted in
the proceedings was "the disposal of residues from
wastewater treatment is a continuously growing
problem. There is inadequate data to determine the field
conditions under which the waste is actually hazardous.
Engineering data suitable for designing safe disposal sites
is almost non-existent. Much more scientific and
engineering effort should be focused in this area."
AES had on several occasions indicated its ability and
willingness to call on its large and knowledgeable
membership to assist in carrying out a project or projects
that would lead to practical solving of some of the waste
problems faced by the metal finishing industry.
As a result AES was asked to address itself to the
problem of disposal of these wastewater residues and to
make a proposal to the Industrial Environmental
Research Laboratory of EPA.
A preliminary proposal was prepared and after some
modification was presented to the council of delegates at
the AES Conference in Washington last June. The
essentials of this proposal were that AES resolved that it
would:
Co-operate and collaborate with EPA to sample,
characterize and code metal finishing sludges
from a variety of metal finishing manufacturing
processes.
Determine, through a literature review, field
studies and dynamic laboratory simulation,
conditions under which leachates are likely to be
generated for all available methods of disposal.
Co-operate with EPA in working out acceptable
test methods and procedures.
The project would be scheduled to be completed within
16 months. The final draft was approved by the AES
directors at the end of October and the Proposal was
shortly thereafter formally presented to EPA. At the
same time the directors approved the mechanics by which
the program would be carried through.
'Kenneth R. Coulter. Consultant
Scarborough, Ontario. Canada
A project manager was appointed and Howard
Schumacher has been selected to carry out this function.
Kenneth R. Coulter was chosen to be Technical Director
and a task force of five AES members is being asked to
serve as advisors to the project.
A subcontractor, Centec Corporation has been chosen
by AES to carry out the sampling and testing procedures.
The function of the Project Manager is to oversee the
financial management of the program. He will serve as
Liaison Officer to the AES Board of Directors who have
ultimate responsibility for the carrying out of the grant
project in co-operation with EPA.
The Technical Project Director, in conjunction with
the Task Force, will be responsible for the selection of the
sites. He will oversee the technical management of the
program including test procedures, with the sub-
contractor and will consult with the task force when
necessary and schedule meetings as required.
The task force will serve as advisor to the technical
director. Members will be responsible for their expenses
although the project manager may authorize
expenditures in special instances.
The sub-contractor will be responsible for conducting
appropriate tests, the accumulation of technical data, the
preparation of technical reports and all financial
documents to meet AES and EPA requirements.
EPA sent the proposal to nearly fifty knowledgeable
people both within and outside EPA for comment. These
comments are now being digested in Cincinnati and the
consensus that will derive from those sources will have
considerable bearing on where emphasis is placed within
the scope of the project. Similarly AES has been
examining their approach to the project and many of the
same conclusions have been reached with regard to
placement of emphasis.
Every effort will be made to avoid duplication of work
being carried out elsewhere in the United States and
overseas. Because of a coincidence in timing of
arrangements it will be possible to get first hand
information from Europe and Japan without the project
having to bear the expense of the travel costs.
Continuous communication with the Office of Solid
Waste will be maintained, both to provide them with
information that may be useful in their determination of
the Toxic Extraction Procedure (TEP) and to keep the
project on the right track in determining what is deemed
to be a hazardous waste. Particularly important will be
the solid-liquid ratios used in running the test procedures.
The first phase, the characterization of sludges will be
32
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designed not only to measure the effect of extraction
procedures at various pH's, but also to pinpoint the
direction to be taken in dynamic laboratory simulation so
as to derive the maximum benefit at least cost. This
project cannot fill in all the gaps of knowledge on all of
the electroplating industry, but it will try to achieve some
significant results in a specific pan of the problem so that
confidence may be placed in its findings.
The success of the whole program will require the co-
operation and assistance of the industry, AES and EPA.
It is the use of this large source of skills and knowledge, as
well as the work of the direct participants that make the
attempt practicable and worthwhile. We are confident
that this co-operation will be readily available.
33
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Methods and Technologies for Reducing
The Generation of Electroplating Sludges
Dr. Clarence Roy*
ABSTRACT
The production of sludge by wastewater treatment systems is of mounting National
concern. The safe disposal of these residues is the subject of continuing study and controversy.
Under these circumstances, it is prudent to minimize or reduce the production of these
materials. A variety of techniques to reduce sludge volume and/or mass are presented in this
paper.
Chemical conservation, water conservation, still and dump control, chemical recovery,
production equipment selection, treatment system design, reagent selection, and sludge
dewatering techniques will be discussed, as they pertain to sludge production. Also included will
be discussions on practices that are detrimental to sludge management and production.
Chemical Conservation
An obvious answer to the problem of excessive sludge
production is to reduce the quantity of metals entering
the effluent stream. There are several ways to accomplish
this objective, but the best one is to start at the source,
where possible, and reduce bath concentrations. Perhaps
the most dramatic trend in this regard is in the strength of
chromium plating baths. Fifteen years ago it was not
uncommon for platers to use bath concentrations with 40
to 50 ounces per gallon, while today, concentrations in
the 20 to 30 ounces per gallon range are most often seen.
Those platers using the more concentrated baths should
immediately investigate the feasibility of changing to
more dilute solutions. This same philosophy should
pertain to every plating bath. In almost every plating tank
using soluble metal anodes, the majority of the plating
solution winds up in the rinse tanks and down the drain.
The old rule of thumb in nickel plating is that the anodes
go on the work while the plating salts are lost as drag-out.
It follows that if plating solutions are more dilute, less
metal salts will be dragged out in a given period of time or
per unit of work processed and sludge volumes will be
reduced proportionately.
The suppliers of proprietary plating baths should be
encouraged to develop and promote even more dilute
baths than are presently available. While this objective
may appear to be contrary to the best interest of the
supplier, it certainly beats losing customers to attrition
from pollution treatment costs, inflationary metal and
manufacturing costs, and the general pressures that tend
to tax the endurance of small- and medium-sized
'Dr. Clarence Roy, President
Aqualogic Inc.
Bethany. Connecticut
businesses. The money they save in reduced production
and pollution treatment costs will remain within the
company for the most part and be spent in other
productive ways in which the supplier can participate.
New manufacturing methods and new production
equipment, modernization of old facilities, automation
of old lines and general expansion programs will work to
the benefit of both the customer and the supplier, and
should not be inhibited by a supplier's concern for the
future of an old product. Times are changing and the
pressures for some changes are inexhorable. Metal and
fuel supplies are dwindling and the suppliers must do
their part to meet the challenge.
By the same token, the platers can not persist in their
bad habits either. Sloppy plating room practices and
outmoded finishing methods are everywhere. They are
accepted with the explanation that it is the way we have
always done it. Or, we have been doing it that way ever
since the war (it seems that America only fought one
war). It is time for the platers and metal finishers to make
an effort to help themselves. Plating shops do not have to
be hell-holes. Many plating shops have grown like
Topsey and they look it. Plumbing is old and make-shift;
the old is mixed with the new. Older tanks in the line have
turned to rust, held together with paint (reinforced rust)
and tank failure is accepted as the cost of doing business.
The topsey-turvy, zig zag work flow encourages floor
spills and dribbles. If the average plant manager or owner
knew dollar value of chemicals lost on the floor of his
shop.he would put a stop to a large part of it. Some
dribbles can not be avoided and shop floors will always
be wet; but they do not have to be ankle deep in blue,
green, orange and grey solutions. When the concrete
floor is fizzing like the well known stomach remedy, you
have to believe that there is room for improvement, not
34
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accept it with a chuckle as a way of life. Attitudes will be
important, but first the people have to have something to
work with.
In hand lines the tank layout should be rearranged to
coincide with work flow. Then, rest bars should be
installed over the process tanks and even over rinse tanks.
These measures will produce less floor contaminants that
ultimately are converted to sludge, and also conserve
chemicals. The complaint has been made that rest bars
slow production, while allowing racks to drain. It should
be noted that as much time (and more labor) is expended
in carrying work back and forth in the plating room than
allowing it to drain properly. Drain boards between
tanks keep solutions off the floor and in the process tank.
Archaic and wasteful practices must be eliminated.
Such extravagances as cleaning, stripping and
phosphating in oblique barrels have no place in modern
production methods. The waste in dollars and chemicals
is unbelievable, the sludge produced, mountainous. In
one plant $50,000 worth of chemicals are used to tumble
phosphate work that should be done for $2,000 by
modern methods. The phosphate level in the effluent
plays havoc with settling and no amount of
polyelectrolyte can correct the condition. Tons of
coagulants must be added to precipitate the phosphate
and create huge amounts of sludge. Every plater must
examine his own activities and eliminate those practices
that resemble the example described.
Another aspect of chemical conservation that deserves
attention is the topic of spills and dumps. Spills were
mentioned previously in connection with the condition of
plating room equipment. Accidental or deliberate release
of large volumes of strong process solutions have, to say
the least, a disruptive effect upon waste treatment
systems. Dumps can be managed, but spills are seldom
caught and treated properly. In any case, these two events
make a considerable contribution to sludge production.
Spills are unnecessary and must be stopped through
preventative maintenance, replacement of marginal
tanks, constant concern and vigilance. Dumps can be
managed by slowly trickle feeding these solutions into the
appropriate point in the waste treatment system. This
practice will minimize consequential sludge production
but not eliminate it.
The plater and the companies involved in finishing
must examine their own dump practices on a tank by
tank basis. Many dumps are unnecessary, made through
habit like a Saturday bath. Others say they would rather
dump a tank than risk reject. Experimenting with
extending dump schedules could lead to problems with
the quality control people or hell raising from the boss or
a big customer. The risk is worth the effort. Any dump
that is extended or avoided has economic justification
plus the benefit of minimizing sludge production. Work
at it. Basically, baths are dumped because of exhaustion
(presumed) or contamination. Filtering, skimming and
corrective additives are useful in many cases. Better
housekeeping, rack maintenance, and avoiding cross
contamination resulting from transporting dripping
barrels and racks over tanks that are incompatable will
help reduce dumps. Suppliers could help the situation by
developing formulations that last longer and additions
that correct contaminated baths.
Water Conservation
The matter of water usage and its impact upon sludge
production may not be immediately obvious, consider
that the wastewater treatment system that uses a lime
slurry to neutralize acids normally operates with a set
point pH in the 9 to 9.5 range. When tap water with a pH
near 7 flows through the system, it demands the addition
of lime. In actual practice, the effect of dilution is not as
dramatic as in the plain water case, but it still prevails,
and causes an unnecessary addition to the sludge burden.
Similarly, an increasing number of treatment systems
add coagulating agents, such as calcium chloride, ferric
chloride, and aluminum chloride. Normally, addition of
these materials is made by flow pacing. Thus as the flow
increases, the reagent addition increases. If the flows are
dilute, the same condition can prevail as in the lime
situation and sludge produced unnecessarily.
With water usage now implicated in the matter of
unnecessary sludge production, it is incumbent upon the
plater to conserve water. Volumes have been written on
this subject, but some of the more significant methods
bear repeating. Counterflow rinsing is without a doubt,
the most important and universally applicable
conservation method. Flow restrictors and combination
flow restrictor-aerators produce dramatic flow
reductions with minimal investment. Aeration with plant
air or inexpensive compressors on critical rinse tanks
produce better rinsing with less water. Single tank spray
rinsing and counter flow spray rinsing are extremely
important conservation methods and deserve much
wider application. Conductivity controllers work well in
rinse tanks that have sufficient recovery time to allow the
device to function, such as low production hand lines.
Foot operated valves and flow actuated timer valves
should be installed on idle rinse tanks.
Chemical Recovery
The prospect of recovering metal and chemical values
is well known to most metal finishers, and needs little
introduction here. A variety of technology is available to
accomplish this objective. Perhaps the simplest and most
overlooked recovery method is direct dragout recovery.
A still rinse following the plating tank serves to collect the
concentrated process solutions carried in or on the parts,
racks, or barrels. Periodically, the strong solution in the
dragout tank is returned to the plating tank. Naturally,
the volume returned is limited to the volume made
available in the process tank by evaporation. Subsequent
rinse tanks can be counterflowed to the dragout tank in
some cases and the efficiency of the recovery process
improved. In fact, with four or five rinse tanks in series,
the entire flow can be recovered. As with most other
recovery techniques, it is important to obtain maximum
rinsing efficiency with a minimum amount of water.
Direct dragout recovery has been automated and is
35
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now commercially available in a number of variations
that can accomodate most circumstances prevailing in
the plating shop. Recoveries range from 50 to 100%,
depending upon the rinse and evaporation rates of the
application.
Two membrane recovery systems, reverse osmosis
(RO) and electrodialysis (ED) are commercially
available; and one technique, Donnan dialysis, is under
development. RO has proven its value in a number and
variety of plating rinse recoveries. It is proven technology
with well defined limitations. Most RO limitations are
related to membrane stability, but with intelligent
application, satisfactory performance is routinely
achieved. While electrodialysis does not have the number
or variety of applications that RO enjoys in the plating
industry, it is beginning to demonstrate its value in
recovery technology. The membrane material may be
able to offer greater chemical resistance in certain
applications than RO, thus making the two methods
potentially complimentary in some plating shops.
Distillation has been widely, and successfully, applied to
metal-bearing rinses. Most limitations relate to the
mechanics of design, materials of construction, cooling
and vacuum water requirements, and energy demand.
Judicious and intelligent applications will justify its
consideration in the recovery scene.
Ion exchange technology has for many years proven it
worth to the electroplater. Improved resin and
equipment have extended the potentials for the
technology. The volumes of regenerant required are
sometimes excessive and the resultant solution requires
evaporative concentration before it can be returned to the
plating tank. It should also be added that on occasion RO
and ED can suffer from this same problem.
In an overview of recovery technology, such as
presented here, it is appropriate to consider the relative
flow capacities. In this respect on a dollar per gallon
capital basis, ion exchange has the highest capacity and
may be the method of choice in those cases where the
possibilities for water conservation are limited by the
space available, as in many automatic plating machines.
With appropriate water conservation measures, reverse
osmosis ranks next in flow versus capital dollars. With
limited information ED appears to rank next, while
distillation follows in the ranking. It should be noted that
on the basis of operating and maintenance costs, ease of
operation, chemical resistance, and chemical capacity,
these rankings could change. It is therefore important to
consider every aspect of each technology before selecting
one for a specific application.
Automatic direct dragout recovery requires good
water conservation as do most recovery methods; but
because the capital costs are so much less than the others,
it belongs in a class by itself.
All recovery technology is dependent upon the purity
of water used to make up for the volumes of rinse water
lost to evaporation. The tap water impurities eventually
become concentrated in the plating tank, and can
interfere with the process. This fact has often been
overlooked, and has led to some of the complaints about
contaminant build-up in recovery systems. The problem
is easily corrected by small ion exchange column or
reverse osmosis units.
System Design
System design can have a important impact upon
sludge volumes. Averaging tanks or large effluent
collection tanks are often regarded as a luxury in the
treatment of metal finishing wastes. There are a number
of good reasons for employing the averaging concept, but
the fact that averaging can reduce sludge volumes deserve
mention here. The composition and pH of metal finishing
wastewater tend to fluctuate rapidly. Smaller plating
shops may demonstrate greater instability than larger
plants. Generally, the composition follows the activities
in progress at any given moment. This accounts for the
greater uniformity sometimes observed in the larger
plants where cleaning rinses tend to off-set pickling, etc.
However, almost all discharges show some fluctuation.
Fluctuation in composition and/or pH results in
system design requirements to accomodate this
condition. In the case of pH, the controls must be
responsive to these excursions.
Rapid addition of lime in response to a rapidly falling
pH can cause the addition of excess lime, particularly if
small mixing tanks are employed. Larger mixing tanks
will allow the solid lime to dissolve in the neutralization
process. Phosphates, sulfates and fluorides can form
insoluble compounds on the surface of the lime particles
and suppress particle dissolution. Oils, greases and some
organics may have the same effect. While these reactions
can be beneficial to the effluent quality, they also
contribute to sludge bulk by inhibiting the lime
dissolution process. Systems employing sodium
hydroxide solutions in the neutralization process do not
suffer from the bulk created by lime, but they may require
the addition of coagulants to assume the collateral duties
of the lime. The use of lime can be expected to produce a
sludge volume between three and six times the volumes
obtained with sodium hydroxide. It is therefore
extremely important to design the treatment system to
make the most efficient use of the lime. Averaging of
effluent composition is one of the best ways to work
toward this goal.
Coagulants are added to the flow to accomplish those
activities described for lime. The fact that they are pace-
fed requires that they be fed at a rate sufficient to handle
peak loadings of phosphates, detergents, oil, greases or
other materials requiring their application. Obviously,
the application rate could be greatly reduced if the
loadings of these materials were more uniform. Here
again, averaging of composition prior to treatment,
assures minimum dose rates and minimizes the resultant
sludge volumes.
Another aspect of system design that has a profound
effect upon sludge volumes is the matter of sludge
thickening. Almost all systems based upon sedimentation
technology produce a liquid sludge of comparable water
content, usually in the 98 to 99% range. Disposition of
36
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these residues in an as-is state is becoming increasingly
difficult and expensive. Many older systems and almost
all new systems have provisions for dewatering these
liquids. It is axiomatic that the thicker the sludge, the
more effective will be the dewatering. This observation
applies to both filters and centrifuges and is probably
relevant to sand beds. It follows then, that it is important
to present to the dewatering stage, as high a solids content
as possible. Sludge thickening can be performed in the
settling tank or clarifier, or it can be done as a separate
activity. Economics do not favor the latter, but it is still
being done in many cases, perhaps because it is a
common practice in sanitary treatment systems. Some
suppliers have combined settling, sludge thickening, and
collecting into a single unit. In one case, where a pressure
filter was used for dewatering, it was observed that when
the liquid sludge presented to the filter contained 5%
solids, the filter cycle was 70 minutes and the sludge cake
produced had a 48% solids content. When the same filter
had a 2% solids content in the feed, the cycle time was
about 2 hours and the solids content of the filter cake was
38%. A similar observation was made in a centrifuge
application where the solids content was about 15% in the
one case and 22% in the other. These percentages are
expressed on a weight basis, and do not reflect their
actual effect upon sludge volumes. Most sludge haulers
charge on the basis of volumes. Shrinkage of sludge cake
volume with increasing solids content is not linear and it
is sometimes difficult to justify the drier cake on the basis
of volume alone. Specifications for sludge composition in
landfills is not very precise at the moment. Usually, the
authorities require that the sludge be "non-bleeding" or
"suitable for landfill", etc. More specific requirements are
expected in the future and the plater is advised to watch
this situation as it develops.
The matter of volume versus solids content also
influences the selection of dewatering equipment.
Generally, sand beds and simple gravity systems will
produce a jell-like residue having between 7 and 15%
solids. Most centrifuges produce a dewatered product
with between 10 and 25% solids, depending upon feed
concentration and centrifuge design. Vacuum filtration
will produce a sludge having between 15 to 30%, again,
depending upon feed rate, filter design and operating
conditions. Pressure filters may be expected to produce
sludge cakes with between 25 and 50% solids, depending
upon the same variables as the other methods. Naturally,
the operating pressure is a big factor in the determination
of solids content.
Future Considerations
The selection of methods described for reducing the
generation of sludge is based on two major
considerations—economics (capital costs) and the
dimension of the problem. Eventually, on a national
basis, metal finishers will face additional pressures, such
as those being experienced in some states now; i.e.,
increased transportation costs for hauling sludge, and the
percentage of solids acceptable in sludge being landfilled.
37
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Applicability of the Federal Republic of Germany's
Centralized Waste Treatment Approach
In the United States
Paul S. Minor and Roger J. Batstone*
INTRODUCTION
This morning we have heard about both the EPA
pretreatment regulations and the proposed RCRA
requirements related to hazardous wastes. The legislation
raises some serious economic questions. The installation
of pretreatment technology and the subsequent sludge
and/or concentrated waste disposal will create a severe
capital and operating cost problem for many
electroplaters—perhaps to the point where some smaller
manufacturers will be at such a competitive disadvantage
that they will not be able to continue in business. In
addition, the costs of these controls if not minimized by
good engineering and common sense — could have the
undesirable effect of adding to the price disadvantage of
American products. It certainly appears that the nation
must wisely manage the resources to be spent on meeting
these regulatory requirements.
The basic reason for the economic disadvantages of the
smaller individual plater, of course is the engineering fact
related to economics of scale. It is simply more expensive
on a cost-per-volume basis to treat small flows in a small
treatment plant than it is to treat larger amounts of waste
in a scaled-up treatment plant. This is especially true for
metal finishing wastes where specialized equipment is
required for each type of waste.
These basic facts have always made centralized waste
treatment very tempting. In the case of municipal
wastewater, regional treatment is a reality in the United
States and is strongly encouraged. There are also some
very specialized industrial situations where centralized
treatment has been successfully applied—and some
private centralized treatment systems are certainly in
business. However, at this time, centralized treatment of
metal finishing wastes has just not developed to the point
where it would offer significant relief to the majority of
metal finishers.
Probably the best example of thesuccess of centralized
treatment of industrial wastes—largely metal finishing-
is in the Ruhr Valley in Germany.
The Ruhr Catchment Basin in Northwest Germany is
one of the most highly industrialized areas in the world.
The hub of this area is Essen, which is the site of the
original Krupp Steel and Armament Works. In this area,
there are about 200 industrial installations that operate
about 1000 plating, anodizing, and nonferrous metal
pickling baths. In the early sixties, this area suffered from
extensive water pollution with all municipal treatment
plants experiencing frequent upsets due to highly
concentrated discharges of industrial wastes.
In 1964, the first municipally operated waste treatment
installation devoted entirely to industrial wastes was built
near the Iserlohn municipal treatment plant. The project
was jointly funded by industry and the municipality, and
charges were set to make it self-sustaining. All
concentrated industrial wastes were required to be either
taken to this facility or be sent to other specialized
treatment facilities.
Since then, several other private and publicly owned
facilities have been installed in the area, and a segregated
landfill area has been added. The improvement in the
environmental quality of the Ruhr Valley in the last 15
years has been noticed by almost every returning visitor,
and it certainly appears that the economic strength of
Germany has not been hurt. A presentation on the
German centralized treatment concept was made in
Canada in 1975* by Norman Roesler, who directs the
operation in the Ruhr Valley. This presentation expresses
general satisfaction with the concept.
With this experience in mind, the EPA Industrial
Environmental Research Laboratory (1ERL) contracted
with CENTEC Corporation to evaluate the German
experience in Essen, as a first step in determining if it
would be applicable in the United States and if so, would
there be major savings in resources and would there be
economic impact.
'Paul S. Minor & Roger J. Batstone
CENTEC Corporation
11800 Sunrise Valley Drive
Reston, Virginia 22091
•-Organization and Operation of Centralized Plants for the Treatment of Special
Wastes from the Metal Finishing Industry," N. Roesler, Department of Sewage
Treatment Ruhrvcrband D-4.1. Essen. Germany. Presented at Technology
Transfer Seminar on Waste Handling Disposal and Recovery in the Metal
Finishing Industries. Toronto. Canada. No\. 12- 1.1. 1975.
38
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In this presentation today, I hope to accomplish two
objectives:
I. Provide an understanding of how the system works
in Germany,
2. Give you a rough idea of the general conditions
under which it will be advantageous to metal
finishers in the U. S. This will be done by presenting
the results of a preliminary economic analysis.
Assumptions for Comparative
Preliminary Economics
Operating Labor
Maintenance Cost
Depreciation
Interest on Capital
Electricity
Overhead
Supervision
Capital Cost
Total Flow Rates
$7.00 per Hour
5% of Initial Investment
20% of Initial Investment
(annualized)
10% of Initial Investment
$.04 per KWH
Assumed to be equal for Both
Centralized and Local
Treatment
Assumed to be equal for
Both Centralized and
Local Treatment
Vendor Quotes System
10,000 gal/day to 1,000,000
gal/day
Mix - CN 10%
- Cr10%
- Neutralization 80%
The following equipment was included in
cost estimates:
Chrome Reduction
Reaction Tank
ORP & pH Probes and Monitors
Mixer
Pumps
Miscellaneous Piping and Electrical Equipment
Cyanide Oxidation
Reaction Tank
ORP & pH Probes and Monitors
Mixers
Pumps
Miscellaneous Piping and Electrical Equipment
Neutralization
Reaction Tank
ORP & pH Probes and Monitors
Mixer
Pumps
Miscellaneous Piping and Electrical Equipment
Clarification
Settling Tank
Skimmer
Sludge Pumps
Miscellaneous Piping and Electrical Equipment
Vacuum Filtration
Vacuum Filter
Pump
Miscellaneous Piping and Electrical Equipment
OVERVIEW OF RUHR VALLEY PRACTICE
In 1964, the administrative agency responsible for the
water resources of the catchment basin of the Ruhr River
(the Ruhrverband) instituted a program to provide
treatment for hazardous industrial wastes at a facility
located adjacent to the municipal waste treatment works
in Iserlohn, Germany. At the same time, a strong effort
was instituted to gain control of the disposal of all
hazardous industrial wastes being generated in the
region. This was accomplished by the encouragement of a
waste exchange system and of strong efforts to provide an
acceptable disposal mechanism for any type of industrial
waste.
The initial centralized system provided for:
Cyanide destruction
Hexavalent chromium reduction
Neutralization
Clarification
Sludge concentration
The treatment options were combined with the
establishment of a segregated area for the disposal of
hydroxide sludges, which as much as possible were kept
separate for potential future recovery. The initial plant
stored the wastes until it was economical to ship them.
The initial funding was obtained from local industries,
the municipalities, and a loan from the federal
government (which was repaid). It was managed by a
Board of Directors consisting of both industrial and
governmental representatives.
Since that time, the number of both private and public
facilities to treat concentrated industrial wastes has
increased to the point where all industrial wastes can be
sent to facilities specially designed for their treatment or
recovery. Facilities are now available for treatment or
recovery of:
• Spent electroplating baths and ion-exchange
regenerates
Chlorinated solvents
Other organic solvents
Spent sulfuric pickle liquor (recovery of acid and
sale of iron oxide)
Spent hydrochloric acid pickle liquor
Oil-water emulsions
Dilute sludges (concentration and disposal)
Concentrated sludges (segregated landfill)
The centralized treatment plant receives inquiries
regarding any waste from the manufacturer who is
referred to a private or public disposal service—or the
treatment plant may directly accept the waste. A regular
waste pickup service is maintained, similar to that for
municipal garbage. All treated effluents from both
private and public industrial waste facilities are sent to a
municipal treatment system.
The prices for the industrial treatment service are such
that all systems are self-sustaining; in the case of private
facilities, they provide a profit. Normal economic forces
have forced large facilities (such as chemical plants) to
39
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provide their own treatment in many cases, while smaller
facilities use outside treatment. The technology used at
these facilities is similar to that utilized in the United
States and is readily available for application in the
United States.
DESCRIPTION OF ZEA ISERLOHN PLANT
Although there are now numerous centralized
facilities, the first was installed in Iserlohn, adjacent to
the municipal treatment plant. Figure 1 shows a flow
scheme for the Iserlohn Plant. Waste acid and waste
alkaline containing cyanide are transported in color-
coded containers. The contents from small containers are
stored in 30-cubic-meter tanks. No distinction is made
between alkaline waste containing cyanide and those free
of cyanide. All are treated as if they contained cyanide.
Certain pickle liquors and baths containing nickel and
copper are kept separate because the nickel and copper
occasionally are sold to a nearby recovery plant which,
through electrodeposition, recovers the metals. As much
of the pickle liquors as possible is transferred to
municipal plants for use as flocculating agents.
The cyanide destruction operates semicontinuously in
three phases. In the first phase, the treatment tank is
partially filled with sodium hypochlorite and caustic
solution. The alkaline waste with the cyanide is added
slowly. During this step, the system is not on oxidation-
reduction potential (ORP) control. In the second phase,
the solution goes on ORP control for final adjustments.
The third phase is final pH adjustment.
Acid wastes also are stored in 30-cubic-meter tanks
until a sufficient amount is accumulated. Thechromate-
containing acids go to a reaction vessel where ferrous
chloride is added as a reducing agent. The effluent from
the acid neutralization, chromate reduction, and cyanide
destruct go to a further reaction vessel where lime is
added for final pH control. From th; neutralization
vessel, the effluent travels to what was intended to be a
clarifier, but because of problems with floating solids, it is
C' TO IWICIML ruufls
UUOGC 10 UUAriLl
essentially operated as a solids-separation vessel in which
floating solids are skimmed. The mid-levei discharge
from the vessel goes to one of three rectangular clarifiers,
which are arranged to be operated in parallel but which,
in reality, operate only one at a time. A breakthrough of
material in one of these clarifiers thus can be valved off.
One is normally kept empty. The overflow from the
clarifiers is pumped to the municipal treatment system.
The sludge underflow at about 2 to 3 percent solids,
passes to a filter press where it is dewatered to about 35 to
45 percent.
The filter press was originally small, but because of
increased sludge dewatering demand, a new, larger press
was installed. Salt corrosion was an initial problem, but
has been solved by the use of plastic-coated cast iron. The
dewatered sludge then goes to a segregated landfill (to be
described shortly).
Waste storage vessels are color coded: red or orange
indicate acid, blue indicates alkaline. Occasionally acid
was mistakenly added to the alkaline solution. In one
instance, enough heat was generated to cause sagging in a
portion of the plastic vent piping. The acid containers
come in sizes up to one cubic meter. Above that size, tank
trucks are used. Since the plant will accept concentrated
plating baths, no concentrated plating baths are
discharged to the sewer. The plant also will accept
neutralized and detoxified plating bath and rinsewater if
sufficiently concentrated. Neutralized wastes are directed
to the clarifiers.
The plant is monitored daily for overflow by the
operators; however, the data was not available to us. The
laboratory takes a 24-hour composite about once per
month. Table I lists the analysis of three of these samples.
At the time of our visit, there had been a malfunction
which allowed large amounts of chromic acid into one
clarifier basin. This clarifier was isolated for recycling to
Fig. 1—Flow Schematic lor ZEA Iserlohn Plant.
Table 1
24-hour Composite Samples from Zea Iserlohn
(All values except pH in mg/l)
11 191 78 8/8/78
Cu
Ni
Zn
Cd
Cr(T)
Cr+"
Fc
NHJ
Nitrate
Nitrite
Cl
Sulfate
Conductivity
(in Ohms)
Cn (total)
(Cl amenable]
pH
3.2
0.7
1.3
0
0
0
2.2
51
1340
92
5000
1485
12.3
18.8
17.6
9.4
3.2 5.0
0.4 1.0
1.2 0.7
0 0
0 0
0 0
0.6 0.67
182
1640
62
12500
2590
34
0.33
0.18
7.8
4.1
0.9
0.4
0
0
0
0.58
5/6/78
7.2
1.9
0.6
0.0
1.02
0.74
2.0
583
3050
102
1800
2285
12.6
0.38
0.31
8.3
7.1
0.9
0.2
0.0
40
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treatment. Although the plant was 14 years old, it was
reasonably neat and well kept, for being built in 1964. It
did not have a significant amoung of automation. The
only major control was on ORP for the cyanide
destruction. The final pH was generally kept between 9
and 10. They do not monitor pH as closely as is common
in the U. S.; there is no continuous pH recorder.
One of the basic goals of the centralized waste
treatment plant is to collect small amounts of waste that
might have value elsewhere if available in sufficient
quantity. Although this function is apparently performed
to some extent (in the case of nickel-copper solution),
obviously no significant amount of exchange takes place
at this site. In further questioning, Mr. Roeslersaid that
the exchange of waste at the plant is not really an
extensive portion of the throughput.
The basic media used to accomplish the exchange of
chemical waste are a series of newsleters that list desired
wastes for sale. These are published weekly by the
German equivalent of the Chamber of Commerce.
Initially, this list was quite extensive, but over the years,
enough contacts had been made so that only a relatively
few wastes need be marketed.
One of the keys to the success of the centralized
treatment concept was the establishment of a segregated
area for hydroxide sludges. The district has established a
sludge disposal site for handling hydroxide sludges from
any type of metal working plant and is not limited to
metal finishers. This facility takes dewatered sludges
only, and single-metal sludges are kept separate for
possible future recovery. The sludges are deposited on the
sides of a deep pit. Any leachate drains to the bottom of
the area and is returned to the treatment plant by gravity.
Currently, they are not being recycled to any extent,
although such sludges are available free from any user.
Mr. Roesler said that, occasionally, a manufacturer
having need for a certain type of metal will take a small
amount of the sludges. At the time of our visit, trucks
were continuously dumping hydroxide sludges. There
were several different colors of sludge, each kept separate
for possible reuse.
Runoff is collected and sent to the waste treatment
plant. At the time of our visit, weeds, mosses, and other
vegetative plants have established themselves on the
hydroxide sludges.
In summary, it can be said that the Iserlohn plant, in
itself, does not represent any new technology. It is the
application of existing technology that has solved the
waste problems of electroplaters in the Essen area.
APPLICABILITY TO THE UNITED STATES
So far we have only heard how the system is working in
Germany, as told by some people who are obviously sold
on the concept for their particular situation. Of greater
interest is its applicability to the United States, taking
into account U. S. costs and U. S. environmental
requirements. One of the striking aspects of applying
centralized treatment to the mix of industries in any
industrial region is the large number of possible
configurations. A thorough examination of the
economics requires a specific study for the local situation,
but in my paper today I am going to try to cover in a
general manner areas where it is likely to offer the
greatest economies.
When evaluating centralized treatment from an
economic viewpoint, you are balancing the decreased
capital and plant operating costs resulting from the
economics of scale against the transportation costs for
delivering the wastes to the centralized treatment plant. If
you are going to evaluate the feasibility of centralized
waste treatment in a regional area, you must know:
I. The sources of industrial waste.
2. The characteristics of the waste being generated.
3. The technology currently installed in the generating
facilities.
4. Special factors that would affect the ability of the
manufacturer to become involved in centralized
waste treatment.
5. The pretreatment requirements.
The evaluation that I am about to present is based
upon several assumptions which, although they may be
realistic at this time, are always subject to the winds of
change.
Figure 2 shows the effect of centralized treatment on
the capital costs that would be allocated to a single plant
versus a number of the equivalent plants of identical
capacity which could subscribe to centralized treatment.
In reality, of course, plants of different capacities would
be subscribing; but this figure illustrates the magnitude of
capital savings.
The shaded curve covers the normal areas of scale-up
for processing equipment. The line drawn in is our
estimate of the scale factor for conventional
electroplating waste treatment systems. The ordinate is
the ratio of costs which would be allocated to a
centralized facility to the costs if the plant installed its
own system. It is a battery limits comparison. It can be
seen that major savings in capital costs occur with as few
as 5 to 10 plants participating; and the bulk of the capital
I!"
JC W V> M »
M0IMI OF CQUtVAlfMT PLANT!
Fig. 2— Effect of Centralized System* on Capital Cotlt Per Plant.
41
-------
savings are realized with 25 plants participating. This is
the basic effect of size on capital costs. This type of capital
savings in scale-up is well known and does not depend on
any significant assumptions.
Before we can examine the total economics of
centralized waste treatment, however, we must provide
some assumptions for the necessary questions. In the
3.0
= 2.0
I
M
0.5
MttKI MOLUB .
Fig. 3—Annual Saving* Venus Ai
Per Day.
JS *0 SO 40
m saoa-«Mxo« twa {•)!«)
HaufcB DWance At 5,000 Gallon*
analysis which follows, we have made the following
assumptions.
• BAT for pretreatment will be reduction of waste
flow, segregation of wastes and conventional
treatment.
• Plants affected have CN, Cr+6, and other metals, and
have no control technology currently installed.
• Comparisons are made for battery limit plant
additions only.
• Plants will continue to use POTW for wastewaters
which meet pretreatment requirements.
The analysis of centralized treatment options is very
burdensome without the use of a computer for the
calculations—and we have analyzed the effects of
different assumptions than these shown—but this
presentation is aimed at illustrating the general principles
of centralized treatment.
Using these assumptions, the annual savings for threee
different plant waste loads as a function of average
hauling distance are shown in Figures 3, 4, and 5 for
5,000, 10,000 and 40,000 GPD, respectively.
The number of plants subscribing are shown as
parameters. The slope of the curves with hauling distance
becomes steeper as the basic plant waste load increases.
This occurs because at larger waste loads, there is less
gain attributed to economics of scale and transportation
costs are important. For waste loads of 5 and 10 thousand
GPD, considerable savings are available at relatively
high hauling distances—while at 40,000 GPD, the break-
3.0
- 2.0
o
3.0
100
0 10 20 JO 40
AVERAGE HAULING DISTANCE PER 5000-GAUON LOAD fralles)
50
Fig. 4—Annual Saving* Versut Average Hauling Distance At 10,000
Gallons Per Day.
o
^
I
5
(A
§
2.0
1.0
10 20 30 40
AVERAGE HAULING DISTANCE PER 5000-GAUON LOAD (miles)
SO
Fig. 5—Annual Saving* Venut Average Hauling Dlitance At 40,000
Gallon* Per Day.
42
-------
55.000
30,000
15.000
lo.poo
15.000
10,000
5,000
10 20 JO W
TRANSPORT DISTANCE (•IWSOOO gillonl)
50
120
100
80
a 60
§
§ 40
5
S
I 20
Fig. 6—Annual Saving* Per Plant Versus Transportation Distance.
0 20 kO 60 80
WASTE LOAD (thousands of g»llons/d*y)
Fig. 7—Break-Even Transport Distance Versus Size of Load.
100
even point occurs at around 20 miles. Figure 6 shows the
three capacities on the same graph and gives the results in
annual savings per plant rather than total for the region.
The increased sensitivity of the savings with hauling
distance is shown very clearly in this figure.
Figure 7 illustrates the effect of waste load on the
break-even hauling distance for the stated transportation
cost—over a wide range of waste loads. The area above
the curve might be considered a normally infeasible
range. This figure shows the very favorable economics for
centralized treatment for smaller waste loads.
Transportation costs are very hard to pin down, since
they are dependent on local conditions. In the data shown
so far, we have used 90 cents per mile since it is an actual
cost for one waste treatment facility leasing a truck. This
figure is the average cost for that location and includes
the salary of the driver, which is a major cost. The loading
time, traffic type, and highway conditions can greatly
affect this number.
Figure 8 shows the effect of transportation costs on the
annual savings for a specific situation where all the plants
are located at IS miles trucking distance. In the case of a
waste load of 40,000 GPD, the break-even point is $1.40
per mile, while the smaller waste loads are relatively
insensitive.
Figure 9 shows the effect of transportation costs on the
hauling distance break-even point.
In an actual situation, of course, there are plants of
various sizes that would choose different options for
interacting with the centralized facility. Many plants
might choose to treat some wastes selectively where it is
most economic to do so, and to send others to a
2fc^
CUTULlUt TUAtnUT
r« w fuurri AT AVIU&I
IS H1LU 'U 5.000 CAUOK1
«.» O.t O.I 1.0
Tunnnnion com l
I.I l.t l.|
Fig. 8— Effect of Transportation Cost On Annual Savings For Three Plant
Waste Loads.
f
1
i
8
1.0
0.)
0.1
\
0 5 10 It 10 15 JO M *» V JO H *0
Fig. 9—Effect of Transportation Cost on Break-Even Points.
43
-------
centralized system. There is considerable room for
optimization within the situation of each plant. Thus, in
the data presented so far, we have force fit a situation and
calculated the savings. In reality, as has happened in
Germany, the plants have been given options and have
selected the one that best fits their needs. There is also the
option of siting several treatment plants so that
transportation costs are minimized.
SUMMARY
• Centralized treatment appears to be working very
well in Germany.
• There appears to be substantial economic savings
for small plants in the United States.
ACKNOWLEDGEMENTS
The authors wish to thank Dr. Norman Roesler and his
staff, for the courteous and thorough assistance in
sharing their experiences in centralized treatment, and to
the U. S. EPA, IERL, Cincinnati, who initiated and have
supported the investigation.
44
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ERA'S Centralized Treatment Program
Alfred B. Craig, Jr.*
Introduction
The Metal Finishing Industry utilizes more than 100
surface finishing and fabricating operatings which
require aqueous application and removal of various
metals to and from metallic and plastic parts. Contained
in metal finishing process baths are various cyanides and
cyanide complexes, hexavalent chrome, copper, nickel,
zinc, cadmium, and other metals which must be disposed
of once the useful life of the bath has been reached. In
addition, rinse waters are generated which contain dilute
concentrations of these metals resulting from washing of
the plated parts.
A vast majority of electroplating shops reside in large
industrial communities in and around municipalities.
Eighty percent of the plants in the electroplating industry
discharge untreated or lightly treated rinse water and
plating baths to municipalities for treatment by
POTW's. These nonbiodegradable pollutants are
discharged in over one billion gallons of process water
each day to biological treatment systems, and hence, are
ineffectively treated by such systems.
Impacts of Metal Finishing Operations
on Publicly Owned Treatment Works (POTW)
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
contaminate the sewage sludge. The metal content of this
sludge may preclude land application of sewage sludge on
food crops; questions also arise regarding sewage sludge
disposal by incineration due to the volatility of cadmium
and lead.
The Enabling Regulations
The Environmental Protection Agency is currently
proposing and promulgating a series of industrial
wastewater pretreatment regulations. These regulations
will reduce the introduction of industrial wastewater
pollutant parameters to publicly-owned treatment works
'Alfred B Craig. Jr
Metals and Inorganic Chemicals Branch
Industrial Environmental Research Laboratory
U S. Environmental Protection Agency. Cincinnati. Ohio
(POTWs). Indirect dischargers, in complying with these
pretreatment regulations, will be required to install
various process wastewater control and treatment
technologies at their plant sites. Some components of the
industrial sector will suffer an economic impact resulting
from adoption of these regulations, and some
components, comprised of plants small in size with
limited personnel and capital for addressing these
regulations will undoubtedly be impacted through plant
closures.
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.
Prior Research on Centralized Treatment
Two years ago, EPA's Office of Research and
Development (ORD), in anticipation of the potential
impact to industry resulting from compliance to pending
wastewater and solid waste regulations, began
investigating conceptual alternatives to on site industrial
waste treatment by generators. One alternative showing
promise is centralized treatment. Scale of economy and
improved waste management are the primary assets of
this approach. Centralized treatment provides
management and personnel whose expertise lies in
handling wastewater and solid waste residuals as a
primary responsibility as opposed to production
personnel providing intermittent supervision of
treatment practices at individual industrial plant sites.
One primary difficulty that ORD encountered in
developing a program on centralized treatment was to
determine the appropriate administrative technique for
implementing this concept. Considered were: (1)
companies with similar processes and pollution problems
located near each other could group together and
construct a centralized treatment facility, (2) private
enterprise could construct centralized treatment facilities
and market treatment to industry located in its vicinity,
and (3) some government organization could establish
and manage its own locally controlled treatment facility.
The first approach was researched through ORD's Metal
and Inorganic Chemicals Branch with a group of
established silver platers in the vicinity of Taunton,
Massachusetts; scale of economy was proven. The
45
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following program outline establishes an approach for
implementation of centralized treatment by both private
enterprise [ (1) and (2) above] and the public sector.
The Metals and Inorganic Chemicals Branch Program
The Metals and Inorganic Chemicals Branch is
developing the procedures to determine, on a case-by-
case basis, the feasibility of centralized treatment
facilities (CTF) for metal finishing wastes. This plan
addresses the usage of the CTF for disposal and
management of the following metal finishing wastes:
• Concentrated, metal bearing wastewaters including
those containing CN and chrome.
• Metal bearing sludges resulting from application of
on-site pretreatment technology.
• Metal bearing sludges resulting from application of
on-site direct discharge treatment technology.
As outlined in the following pages, this detailed plan
provides:
• Screening feasibility studies for 5 regions with high
densities of metal finishing plants (Phase I).
• A detailed study of one region resulting in a
comprehensive design of the collection and disposal
system (Phase II).
• A demonstration of the system designed in Phase II
(Phase III).
• A retrospective analytical evaluation of the
demonstration and appropriate dissemination of the
results (Phase IV).
The primary output from the first two phases will be
the site selection for demonstration and a "blueprint" for
construction of a CTF at the selected demonstration site.
Detailed activities for each of these four phases is
contained in this paper.
This program will:
• Provide EPA and U. S. industry with a cost effective
approach to remedy impacts to industry derived
from complying with pretreatment regulations and
sludge disposal regulations for both industrial
pretreaters and direct dischargers.
• Use municipal governments, as a point of contact
with local industries, for technology and associated
cost information that will enable industry to
economically meet regulations.
• Utilize experienced personnel, whether from the
private or public sector, to operate CTFs to ensure
the long-term control of industrial wastewater
discharges and ultimate safe disposal of sludges.
• Provide, through scale of economy, economical
treatment of metal finishing wastes withoug
hampering potential resource recovery of industrial
residues, such as recovery of strategic metals from
metal finishing wastewaters and sludges.
• Provide an effective solution to industrial waste
disposal in many regions throughout the United
States, and reduce impacts associated with
conscientious waste disposal.
Though the program specifically focuses on the metal
finishing industry, a widespread, complex industry for
which impacts from pretreatment and RCRA regulation
implementation are anticipated to be extreme, it will
contain latitude to include other industrial categories
into subsequent analyses.
PHASE I
DEVELOPMENT OF TOOLS TO AID REGIONS
WITH HIGH METAL FINISHING DENSITIES
IN DECISIONS CONCERNING CWT
AND SELECT AREA FOR CWT DEMONSTRATION
There are four major functions for Phase I:
1. Selecting the regions for case studies.
2. Developing analytical tools and evaluating case
studies.
3. Disseminating results of case studies as examples
for other groups considering CWT.
4. Selecting one region for system design.
1.1 Select Regions for Case Study
The objective of this section is to select 5 regions for
case studies. The selection of these regions will be
based on screening thirty locations using
predetermined selection criteria based on
information collected by a broad-brush survey of
regions with an adequate density of electroplaters.
I.I.I Develop Criteria for Reducing Candidate
Sites From Thirty To Five
A list of recommended criteria used to
narrow the number of candidate sites from
thirty to five will be developed by reviewing
and analyzing project objectives. These
criteria will address technical issues such as
industrial density and profiles as well as
esoteric issues such as the political climate of
in-phase regulations affecting CWT.
1.1.2 Development of Data Base on Candidate
Regions
Each of the regions will be profiled
regarding its industrial community and
municipal ordinances through the use of
Dunn and Bradstreet's Metal Working File
and municipal questionnaire.
1.1.2.1 Dunn and Bradstreet Data
The Dunn and Bradstreet Metal
Working File will be geographi-
cally reviewed using one of the
sorting options available.
Primarily, this source will provide
information concerning the
number and size of metal finishers
in thirty candidate areas.
46
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1.2
1.1.2.2 Municipal Questionnaire
A municipal questionnaire will be
developed and mailed to these
thirty locations requesting infor-
mation from the municipality (such
as regulatory constraints, permit
assignments, and enforcement
procedures) necessary to screen
candidate sites according to the
criteria developed initially. A cover
letter will be mailed with the ques-
tionnaire to inform the
municipalities selected by the D&B
scan of the project's objectives. A
telephone survey will be conducted
to verify questionable information.
Additional, more specific,
information may also be collected
during this survey of candidate
municipalities.
1.1.3 Describe Alternative Regions
A concise report will be prepared for each of
the thirty municipalities considered in the
selection process highlighting information
pertaining to the decision criteria. A
summary report will also be prepared to
provide an overview of the area surveyed
and to include recommendations for the five
case study sites. These recommendations
will be founded on an analysis of informa-
tion collected from D&B, the municipal
questionnaire, and the telephone survey.
Develop Decision Tools and Evaluate Five Case
Studies
The objective of this section is to develop a
computer optimization model to balance the para-
meters affecting feasibility in each case study. Using
these tools, one case study will be chosen for
detailed analysis. The model will be user oriented so
that it can be easily applied to other situations. The
evaluation of the case studies will include recom-
mendations for the demonstration study area. The
location chosen will reflect a positive political and
technical climate for investigating the feasibility of
centralized metal finishing waste treatment.
1.2.1 Develop Industrial Data Base
The information and data necessary to
evaluate the case studies will include sources
and characteristics of wastes, installed
treatment equipment, sludge disposal
mechanisms, etc. and will be organized and
stored in a data base. Information on parti-
cipants to be used in the evaluation will be
obtained from two major sources:
1. Industrial and business information
sources.
2. Industrial questionnaires.
The Dunn and Bradstreet Metal Working
File will be used to identify industrial
sources and for creating a mailing list for the
industrial questionnaire to plants in the
candidate studies. The industrial question-
naire will request sources and characteristics
of wastes, pollution control and process
technology installed, etc. Use of existing
EPA data will be included but cannot
substitute for the cooperation of industrial
people.
1.2.2 Determine Regulatory Constraints
Regulatory constraints will be established
by reviewing development documents,
Department of Transportation (DOT)
regulations, and applicable solid-waste-
management guidelines. The investigation
will include federal, state, and local elements
of regulations and will also concentrate on
regional and local mechanisms for issuing
permits. Specific problems with the
individual studies will be identified.
Enabling ordinances will be studied and
recommendations made if they do not exist.
1.2.3 Develop and Investigate the Use of Decision
Tools for Alternative Areas
The computerized decision tools will be
developed and used to optimize on-site vs.
off-site treatment to maximize the economic
benefits of CWT in the case studies.
1.2.3.1 Develop Decision Tools
The computer model to be used in
evaluating CWT will minimize the
inversely related functions of
transportation and capital operat-
ing costs for on-site and centralized
treatment using mathematical data
and control technology informa-
tion. Its structure will follow prior
work on modeling regional
treatment facilities with the added
feature of incorporating existing
on-site treatment.
1.2.3.2 Develop Scenarios
A series of scenarios for each study,
based on the model output,
regulatory constraints, and other
available information will be
produced. These will be introduced
into the model for selecting an
optimal regional system.
1.2.3.3 Establish Sensitivity of Scenarios
The industrial survey data from the
47
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selected case study sites will be
utilized in the model to determine
the sensitivity of each scenario to
changes in critical variables, such
as hauling costs, political
constraints, treatment capital and
operating expenses to indicate
trends where CWT might not be
feasible.
13 Disseminate Results
Two reports will be developed for Phase I:
1. Capsule report for presenting results on the
thirty original candidate regions citing the
results of the selection procedure of the five
case studies.
2. Project report relating details of the five case
studies.
1.3.1 Present Results to Candidates
A capsule report will be issued to the metal
finishing industry to summarize the results
of the case studies. It will be written in a
concise manner and will rely heavily upon
graphics to give an indication of CWT
feasibility.
1.3.2 Final Report for Phase I
A final engineering report for Phase I will
show results of case studies, document
project activities, present and summarize
data, and describe the analytical model.
PHASE II
DEVELOPMENT OF DETAILED SCHEMATIC
FOR DEMONSTRATION
OF CENTRALIZED TREATMENT CONCEPT
The objective of Phase 11 is to develop a comprehen-
sive plan for a centralized waste treatment (CWT) facility
for a specific location.
2.1 Develop System Design for Demonstration
There are a number of steps that must be
undertaken to design the CWT system properly.
These steps include:
I. Determine optimal scheme for CWT
components including on-site treatment or
concentration of wastes; collection,
transportation, treatment and disposal of
wastes.
2. Design CWT facility based on current
and projected industrial community needs.
3. Determine/develop waste exchange options.
4. Obtain commitments from user companies.
5. Determine technologies for wastewater
minimization and on-site treatment and
associated costs.
6. Develop and secure financing plan.
7. Develop regional ordinances to permit CWT.
These tasks are discussed as follows.
2.1.1 Determine Optimal Scheme for CWT
To determine the optimal size for the CWT
facility and other major system components,
various scenarios will be developed through
modeling with an optimal CWT scheme
forthcoming from the optimization
program.
2.1.1.1 Gather and Analyze Data
To supplement and verify the
information collected in Phase I,
plant surveys will be conducted by
visiting all metal-finishing
dischargers within the designated
area. Prior to the plant visits,
completion of a second question-
naire will be requested to provide
the detail needed by the model.
the detail needed by the model. As
plants are visited, the information
gathered will be reviewed for
validity, entered into the data base,
and analyzed. Economic and
technical trends will be established.
Follow-up telephone calls will be
made if information is inadequate
or missing.
2.1.1.2 Develop Viable Scenarios
Once all information is entered into
the data base, the analytical model
will be utilized to compare the
options available to the area.
When uncertainty exists, various
sets of data will be used to investi-
gate sensitivity. The output of the
modeling exercise will be various
scenarios each bused on valid
assumptions. From this set of
scenarios, an optimal CWT system
will be recommended.
2.1.2 Design Centralized Treatment Facility
The design of the CWT facility will include a
detailed design of the treatment systems for
various dilute and concentrated wastes and
sludge. A segregated landfill will likewise be
designed. The individual tasks to be
performed in this section are:
• Obtain detailed information on plant
influent composition as equalized from
each of the participating sources.
• Selection and coordination of various
treatment steps (process design).
• Sizing of equipment.
48
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• Preliminary design of control schemes.
• Development of process flow diagrams
and process instrumentation diagrams,
equipment specification, and operating
philosophy.
• Ultimate disposal philosophy for solid
waste.
These design criteria will be provided from
modeling results, analysis of regulatory
requirements, estimation of raw waste loads,
and other available information.
2.1.3 Determine/Develop Waste Exchange
Options
Waste exchange options will be investigated
based upon waste materials available and
raw materials currently purchased for
production or treatment processes by the
industrial community.
2.1.4 Obtain Commitments from User
Companies
A cover letter and form will be mailed to
potential user companies that request a
nonbinding commitment to use the CWT
system. Various options will be indicated on
this letter of intent based upon the specifi-
cations of the CWT facility. The treatment
options will be tendered as services to
remove concentrated rinse waters, spent
plating baths, precipitated sludge and
dewatered sludge from plant sites.
2.1.5 Determine Wasiewater Minimization and
On-Site Treatment and Associated Costs
Information collected during plant visits will
be used to determine needs of potential user
companies with respect to waste
minimization. A report on waste-minimiza-
tion techniques that could be applied to
potential user companies will be prepared.
Costs of treatment will be included in the
report.
To disseminate the information to
participating companies, a seminar on waste
minimization for the benefit of potential
user companies may be utilized. Specific
applications will be addressed at the
seminar.
2.1.6 Develop and Secure Financing Plan
Financing alternatives will be recommended
to the region and to the individual
participants.
2.2 Publish Results
A comprehensive final report will be prepared
which shall include:
I. Project objectives.
I. Methodology
3. Model description (users' manual)
4. Case study results
5. CWT system design
6. Conclusions
PHASE III
DESIGN & CONSTRUCTION
OF CENTRALIZED TREATMENT FACILITY
The objective of Phase III will be to complete all
specific plans necessary for facility construction. After
it's construction and "shakedown", sufficient monitoring
and operating data will be obtained in order to fully
evaluate its operation and performance.
3.1 Construction of Facilities
The facilities to be used in the centralized waste
treatment scheme will be turnkeyed during this
time. This will require that all necessary permits be
available prior to construction.
3.2 Acceptance of Facilities
All treatment steps will be tested prior to full
acceptance and operation of the plant. Shakedown
runs will be completed before the facility is open for
full operation.
3.3 Development of Operational
and Administrative Data
Once accepted, the facility will be operated for
sufficient time to determine any administrative and
technical problems. These will be corrected as
necessary and recorded on a final report on the
facility.
PHASE IV
RETROSPECTIVE ANALYSIS
OF PROGRAM AND DEVELOPMENT PROTOCOL
The protocols developed during the course of this
program will be evaluated in terms of their accuracy in
predicting economic and administrative feasibility of
centralized treatment. The results of the program will be
summarized in a capsule report and disseminated
through a program report and /or seminars.
49
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Economical Pretreatment — A Job Shop Case History
F. A. Steward and Henry H. Heinz'
The American Plating Company, an electroplatingjob
shop, has been established in Zelienople, Pennsylvania.
since 1955. The plant's main business since its inception
has been to serve the steel fabricating industry in
Southwestern Pennsylvania, and adjacent regions in
Ohio and West Virginia. The original facilities included
barrel and rack zinc plating, to which a Udylitc umbrella-
type automatic was later added to handle larger steel
structures. The umbrella machine was replaced in 1974
by an in-line programmed hoist machine with I4'X 3'X 7'
deep plating and rinsing modules.
The company considers itself a small job plater with a
labor force of approximately 6-10 people per shift and
an annual billing in the range of SI,000,000. When
planning tor the installation of the plant, it was
recognized that adequate waste treatment facilities would
be needed to avoid harmful effects from toxic chemicals.
(CN and Cr"'), and metals (Cd, Zn, Cr); also potential
corrosive conditions created by the effluent discharged to
the local sew'age treatment plant. Zelienople is a small
community (population 6,000) with, at that lime, a
sewage treatment plant designed for .2 MOD average
daily flow. The discharge from the sewage treatment
plant is to a small stream, extensively used for sport
fishing. In view of the modest-sized local treatment plant
to which the effluent would be discharged, it was thought
that the plant effluent should not exceed \0C"C. of the total
influent and, therefore, that the waste treatment system
should allow significant water conservation.
Description of Plant
As usual with most job plating plants, the original
facilities had to be expanded by additions to the plant
area. The original building had a floor space area of
10.640 ft.:. In 1957 an extension was added to house an
automatic rack plater and new boiler. In I960 a new
loading dock and storage area for work in process was
added, and in 1972 space was created for an in-line,
programmed hoist machine so that the present plant area
occupies approximately 27.500 ft.: floor space. Figure I
shows the floor plan of the plant. Fig. 2 is a plant view.
The only unique feature of the plant design is the floor
contour with careful segregation of all sewer inlets from
the plant floor area, segregation and collection of all
accidental spillage, tank or pump leakage, etc. The
cyanide-containing processing tanks are within a curbed
'F A Steward Vice President Engineering. Lancy
Henry H Hemz. Superintendent. American Plating
l-BOt HC«ll UNI
/,s, nikui, i INI
/INC MATING UNC
PMOSPHATING
PHOCtSS
OMICtV IAB ft WASHROOM
1C G LOADING DOCK
1
L, «UP
Fig. 1 —Plant Floor Plan
Fig. 2-View ol Plant.
area, channeling any cyanide spill to segregated sumps.
Sumps serving the waste treatment system, piping
trenches, and pits are all part of the original building and
subsequent expansion floor plans, so that the original
waste treatment system and improvements could be
easily and inexpensively installed and maintained.
Production Equipment and Volume
A. Barrel plating capacity is based on a six-station, 36"
* 14" barrel, zinc plating line in which originally there was
a three-barrel cadmium unit later converted to zinc.
Cleaning and pickling occurs in the plating barrels, while
rinsing is through an automated hopper line, the work
automatically discharged into a gas-heated spiral dryer.
The D.C. power is supplied by an 18V. 6000 A rectifier.
The average surface area plated in an hour is 250 ft.:.
B. The automatic rack machine is an ancient Munning
automatic, processing racks 20" wide, 27" long, and 6"
deep. Capacity is approximately 100 racks per hour, with
a zinc thickness specification of 0.0008". The D. C. power
is 9 V, 15,000 A. The average surface area plated per hour
is 360 ft.*'.
50
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C. The in-line programmed hoist plater has ten plating
stations for racks on a crossbar, each accommodating
work up to I2'X5'* 10" deep. The available D.C. power
supply is 9 V, 75,000 A. The average surface area handled
is 1,584 ft.2 per hour. The average zinc plating thickness
specification is 0.0008".
D. An overhead bridge crane operated cleaning and
pickling line consists of 21' * 4' « 7'deep alkali cleaning,
hot sulfuricacid pickling and rinsing tanks. This system is
used intermittently for prepickling of hot rolled, rusted,
or heavily oiled or flaked hot dip galvanized parts to be
plated or stripped; and sometimes also for contract
pickling work.
E. A zinc phosphating line under a monorail consists
of a phosphating tank 5' * 3' * 3' deep with a rotating
barrel, equipped with the usual cleaning, rinsing, oiling,
and centrifuging facilities. The line is operated
intermittently and has a capacity of 250 ft.: production in
an hour.
The company also operates two trailer trucks of 30 ton
total payload capacity for the convenience of their
customers, picking up and delivering work in the nearby
area.
Since August 2, 1978 (from which time this report and
cost analysis have been prepared), the plant has been
operating two shifts, 21 hours/ day, five days per week.
Cost data, water consumption and effluent
characteristics are all based on this present production
volume.
Evaluation of the Waste Treatment Facilities
(a) 1955
The original waste treatment installation at the time of
the plant start-up consisted of two Closed-Loop
Treatment Rinse (CLTR) systems, one following each
cyanide-containing processing step and the other
following each chromating process.
Additionally, a waste acid storage tank was installed
with the necessary pumping facilities to receive dumped
waste acids, cleaners, and accumulating sludges from the
treatment rinse systems, treated sludges from the yearly
maintenance cleaning of plating tanks, etc. In the
Pittsburgh area a number of steel companies are using
waste hauling and treatment services on a long-range
contract basis. This approach is therefore economical for
the plant and avoids the burden of sludge handling and
disposal.
TABLE I
MASS DISCHARGE LEVELS
OF POLLUTIONAL PARAMETERS
Cyanide (exclusing iron cyanide)
Cyanates (CNO)
Zinc (Zn)
Chromium (trivalent) (Cr")
Chromium (hexavalent) (Cr"1)
Cadmium (Cd)
Iron (Fe)
0.028 Ib.
0.1 Sib.
0.224 Ib.
0.224 Ib.
0.056 Ib.
0.224 Ib.
0.55 Ib.
/hour
/hour
/hour
/hour
/hour
/hour
/hour
It didn't appear necessary to provide a pH control
system for the effluent since the cleaners and highly
alkaline treatment rinses have maintained a neutral or
alkaline pH. The installation of a settling tank for the
final effluent didn't appear necessary cither. The CLTR
systems capture the metals in the dragout.
The effluent flow volume at this time was in the range
of 15-20 GPM and has met the stipulated requirements of
the consultants of the local sewage treatment plant.
The agreed-upon limits were as shown in Table I.
With the installation of the rack automatic plater and
the umbrella automatic, the effluent flow volume
increased to 40-50 GPM. The zinc, cadmium, and iron
levels in the effluent increased to the point that the
company was found to be in violation of the mass
discharge limits that were stipulated. Although the
sewage treatment plant capacity was also more than
doubled (.5 MGD), the consultants of the sewage
treatment plant felt that safeguards were needed against
potential pass-through of iron cyanides into the stream
stocked with fish. Therefore the cyanide limits were
changed to also include iron cyanides.
The new maximum level of discharge for CN was now
0.035 Ibs./hour, but included iron cyanides. Calculating
the stipulated maximum allowable residuals with an
effluent flow rate of 50 GPM, it was found that the
pollutant concentrations would have to be maintained
below the levels shown in Table II.
The iron cyanides in the zinc plating solutions were
high and couldn't be easily reduced with chlorination; the
cooling water requirements, in view of the high current
density plating systems, continued to increase; and the
costs for water and sewer rental were continually
increasing. Therefore, it was decided to install additional
facilities to meet the future requirements. Two systems
were added:
(1) An additional CLTR system for neutralization of
acid and alkali treatment processes; and
(2) A recirculating cooling water system.
The neutralizing treatment rinse was used after
cleaners, acids, phosphating, and after the cyanide
treatment rinses. It provided effective chemical rinsing so
that a total water consumption and discharge of 12-15
GPM) flow rate, we have 454:57 = 7.57 as a multiplying
factor to be used for the conversion of concentration
trouble-free compliance with the agreed-upon limits for
the residuals.
TABLE II
CALCULATED RESIDUALS
BASED ON 50 GPM EFFLUENT FLOW
CN (total)
CNO
Zn (total)
Cr"
Cr"
Cd (total)
Fe (total)
I.I mg
4.9 mg
8.9 mg
8.9 mg
1.8 mg
8.9 mg
18 mg
51
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A cooling tower was installed to allow recirculation of
the cooling waters. The cooling tower discharges to a
reservoir tank from where the water is recirculated back
to the heat exchangers and serves also the rinse tanks.
Rinse water provides the blowdown for the recirculated
cooling water. Fresh water is added to the cooling water
reservoir to make up for the rinse water consumption. To
guard against possible undetected cyanide leaks from the
heat exchangers into the cooling water, a cyanide
monitor/controller with hypochlorite feed and alarm has
also been installed.
The New EPA Pretreatment Regulations
In February, EPA published Proposed Pretreatment
Standards for the Electroplating Category. In the
interim, a large regional sewage treatment plant was
being built which would take over the sanitary waste
treatment responsibilities from, among others, the
Zelienople treatment plant. The Authority of the regional
plant and their consultants do not feel bound by the
agreement regarding the allowable residuals that have
been in force for the last 22 years, but expect American
Plating to meet the proposed EPA guidelines by the time
the new regional system begins operation, at year-end
1978. The guidelines proposed in February, 1978, do not
mention the applicable mass discharge limits. It is evident
that a plant which through the years has followed a
design concept of aiming for improved waste treatment
by chemical rinsing or other water conservation practices
would be at a serious disadvantage if mass discharge
limits could not be considered. EPA's General
Pretreatment Standards (Fed. Reg. 6/28/78) correct this
omission, and indicate that the final pretreatment
TABLE III
CONVERSION OF EPA'S CONCENTRATION LIMITS
BASED ON ALLOWABLE MASS DISCHARGE
Zelienople Limits Febn 1978 EPA
at 15 GPM
c\"
CV
Cr"
Cr'
Zn'
Total Metals
included in CNi
3.8 mg/l
6.1
30.3
24.2
Max. /Day
1.5 me 1
4.8
1.9
.11. X
25.7
56.K
JO Hay A \v.
0.6 my
1.8
(1.7
12.1
11.3
29.5
1
regulation for each industrial category, although written
with concentration limits, will provide equivalent mass
limits so that the local or state regulatory agency may use
these instead of the concentration limits.
EPA's Guidelines Division has not yet decided what
the calculation factors will be, but believes the mass limits
will be based on surface area processed and the number of
operations, similar to the approach used for the proposed
Electroplating Direct Discharge Regulations published
in April, 1975. These have been set aside, awaiting
reappraisal. Therefore, our calculations have to be based
on assumptions. For example, we feel strongly that
cleaning and pickling should each be accepted as an
"operation," but we calculated on the basis of only two
operations—plating and chromating. Similarly, not
knowing what water consumption rate will be eventually
assumed, we have calculated the anticipated EPA
requirements on the basis of 80 l/m^operation. To be
conservative, we have also assumed that in view of job
plating practices, it would be safer to consider only two of
the five processing lines in operation at any one time.
Thus, we have taken the automatic hoist line (1,584
ft.2/hour) and barrel line (250 ft.2/hour) to give a total
production rate of 1,834 ft.2/hour.
Our calculations therefore show:
1,834 ft.-/hour = 2.84 m2/min.
2.84 m:/min. x 2 operations * 80 liters/ m-operation =
454.3 l/min.
Dividing 454.3 I/ min. by the actual flow rate gives us a
multiplier factor to apply against the concentration limits
of each parameter as given in the EPA Proposed
Guidelines for Pretreatment for the Electroplating
Category. Assuming 57 I/minute (approximately 15
GPM) flow rate, we have 454:60 = 7.57 as a multiplying
factor to be used for the conversion of concentration
limits to be on a mass discharge basis.
Table 111 shows the calculated allowable residuals:
Comparing these allowable residuals with the results of
routine analytical analyses, as shown in Table IV, shows
that the plant is safely below the anticipated federal
requirements.
Current Plans - A Further Improvement
Recognizing that the discharge rate is so close to the
10,000 gallons/day definition for a small plant makes a
further reduction in water usage appear attractive.
TABLE IV
TABULATED ANALYTICAL RESULTS
fiitnin
CNA
CN1
cr
Cr1
ZN1
Total Metals
PH
8/30/78
(1.43
0.43
<0.()l
-------
Achieving classification as a small plant would allow a
reduction in analysis and monitoring costs for both the
plant and Regional Authority for zinc, iron, total
chromium, etc. The proposed EPA regulations didn't
spell out whether the 10,000 gallons/day applies to an 8-
hour working day or a 24-hour calendar day. Because the
plant had to meet the Regional Sewage Authority
deadline before the end of the year, and because the
actual manner for the calculation of mass discharge limits
is not officially available, further steps are being taken on
the conservative assumption that EPA meant 10,000
gal./calendar day. After tightening up all unneccessary
water usage in the plant, it is believed that with the
addition of a better steam condensatc return system, the
discharged process wastes will be safely within the 10,000
GPD small plant category. Table V shows the daily water
consumption volume and the manner this has been
reduced since August I when this program started. The
10,000 GPD reflects on all the water used in the plant,
including sanitary consumption. (10,000 GPD converted
for 21-hour operation indicates 7.9 GPM total water
usage).
The new equipment that has been ordered but not yet
installed consists of a condensate collection and pumping
system, including conductivity monitoring and alarm.
The anticipated savings amount to approximately 3,000-
3,500 GPD of high-quality hot water. This installation
will save in water, boiler treatment chemicals, and
heating energy. The system should pay for itself within
six months.
Under these conditions, according to the February,
1978, proposed EPA standards for plants discharging
less than 10,000 GPD process waste, the effluent
requirements for the plant would be limited to the
parameters shown in Table VI.
Based on the routine analyses, as have been shown in
Table IV. the EPA requirements can be met without any
changes in the waste treatment system.
Zinc Plating Process Sequence
A brief explanation of the Closed-Loop Treatment
Rinse approach and the processing sequence will
illustrate how such unusually low water consumption can
be achieved.
The CLTR concept employs chemical rinses to remove
the d ragout film from the metal surface emerging from a
processing solution. The chemical rinse is so formulated
that an excess of treatment chemicals is available to
eliminate the particular harmful content in the d ragout.
The chemical to be treated may be cyanide, hexavalent
chromium, metals to be precipitated, or just acidity or
alkalinity to be neutrali/.ed. The treatment solution is
recirculated from rinse tanks in the processing lines to a
reservoir which serves also as a settling tank for the
precipitates. Chemical depletion due to reactions with the
d ragout is replenished by chemical additions, most often
through an automatic controller. The final rinse waters
or fresh water additions at a low flow rate create a blow-
down for each system so that the total dissolved salt
concentration is held constant.
DAILY
Date
X 30 78
9 7 7K
9 14 7«
10 10 7K
10 20 7X
II 30 7X
TABLE V
EFFLUENT VOLUME
Operating Hrs.
17
17
17
17
17
17
a pn
14X60
912(1
X050
7300
4.110
39KO
TABLE VI
EFFLUENT LIMITS FOR PLANTS DISCHARGING
LESS THAN 10,000 GPD PROCESS WASTE
CNA
Cr
Max./day
2mg/l
0.25
30 Day Ave.
0.8 mg/l
0.09
LOAD - UNLOAD
DRY
HOT
WATER RINSE
Cr CLTR
CH ROM ATE DIP
NITRIC ACID DIP
ELECTROLYTIC
ACID CLEAN
NEUTRALIZING CLTR
CN CLTR
C
Cfl DIP
ZINC PLATE
3
HOT WATER 2 GPM
hi
D
FRtSH WATER 2.5
Fig. 3—Proceii Sequtne*.
53
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In the American Plating installation, as described
earlier, three CLTR systems are used. The "Cyanide
Treatment" is an alkaline solution containing 1,500-1,800
mg/1 chlorine; the "Chromium Treatment" is an alkaline
solution containing 300-500 mg 1 hydrazine as a reducer;
the "Neutralize Rinse" is a slightly alkaline solution
maintained by caustic soda or sulfuric acid additions.
To illustrate the processing sequence and fresh water
usage. Figure 3 is a schematic view of the automatic hoist
process line.
As can be seen from Figure 3, throughout the
processing cycle, chemical rinsing is employed and fresh
water is used only for final rinsing and the hot water rinse.
The concept is not new; many installations designed and
supplied by Lancy achieve even greater water
conservation by recycling the final rinses through an ion
exchange system.
Probably unique to this plant is the extensive use of
electrolytic acid cleaners. These not only save a process
and rinse step, and thereby reduce chemical loading on
the waste treatment system, but they also shorten the
plating line, saving space and time for the automatic
hoists.
Waste Treatment Equipment and Installation Cost
It is nearly impossible to reconstruct accurately the
equipment and installation costs because the major part
of the installation was paid for with 1954 and 1960
dollars; the installation was done by plant personnel; and
all costs have been amortized a long time ago. Checking
old records and reconstructing the events, a conservative
estimate is as follows:
1954 Two Integrated Treatment System reservoir
and sump tanks, level controllers, pumps,
hypochlorite solution, and waste acid storage
tanks, installation, piping, wiring, etc.
$12,000.
I960 integrated Neutralize System Reservoir, sump
tanks, level controllers, pumps, stock solution
tanks for caustic soda, sulfuric acid, pH controller
14.000.
Cooling water monitor cyanide and controller
installed 3,000.
1978 Estimated: Condensate return collecting system
with pumps, monitor, and controller, installed
5,000.
Total Capital Cost $34,000.
Note: This excludes the cooling water system
which is considered process equipment.
b. Chemicals:
Hypochlorite - 2,675 gal. @ $.55/gal. $1,471.25
Caustic Soda - 5.750 Ibs. @ $0.16/lb. 955.08
Sulfuric Acid - 576 gal. @ $0.46/gal. 264.96
Hydrazine - 270 Ibs. @ S2.00/ Ib. 540.00
Soda Ash - 120 Ibs. @ $.05/lb. 6.00
Total Chemical Cost $3,237.29
c. Labor:
Foremen (2) - waste treatment checks -
!4 hr./shift = 20 hrs/mo.
Foreman (I) - daily spot checks -
'A hr./day = 10 hrs/mo.
@ $10.01/hour 300.30
Operating Labor (2) - chemicals make-up.
checking, 15 min./shift =
20 hrs./mo. @ $5.42/hour = 108.40
Total Labor Cost 408.70
d. Maintenance
Labor, maintenance men (2) -
5 hrs./week ea.
@$6.43/hour 257.20
Material, spare parts/mo. 300.00
Total Maintenance 557.20
e. Outside laboratory analysis services,
once per month 100.00
Total Operating Costs, Waste Treatment $7,903.19/ mo.
B. Savings Through Reduced Water Consumption:
Present water charges are S0.674/ M gallons; the
sewer rental cost is $0.575/ M gallons for a total of
I.249/M gallons.
Using the EPA minimal water usage formula of 80
l/m2-operation x 2 operations x the surface area
processed, which in this case is 2.84 m2/minute (two
process lines in operation), as calculated before, gives
454.3 I/minute as a flow volume.
This flow rate gives a daily (21 hr.) water usage
factor of 150,636 gallons. Taking, as before. 20 work-
ing days/month, and the combined water and waste
water cost of S1.249/M gallons, it may be conserva-
tively projected that without water conservation in
waste treatment, the cost would be $3,762.89
The present water usage is less than 10,000 GPI>
(21 hrs.) (includes sanitary usage also); for a 20-day
month, this is
249.80
This amounts to a saving of
$3,513.09
Waste Treatment Operating
and Maintenance Costs and Savings
A. Total Costs:
a. Acid and sludge disposal - 4,500 gal/load,
8 loads /month @ $0.10/gallon
$3,600
C. Net Costs:
Deducting the savings from the total costs of
$7,903.19, the actual monthly operating and mainte-
nance cost is $4,390.01.
Considering the average plant operating costs, which
are $85,000/ month, it appears that the waste treat-
ment cost is 5.16% of the operating cost.
54
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City of Grand Rapids, Michigan
Program of Industrial Waste Control
James A. Biener*
Introduction
Over the past nine years, the City of Grand Rapids has
experienced the differential effects of both non-control of
industrial pollutants and tight regulation of industry's
use of sanitary sewer system. This paper is presented in
order to share the experiences of Grand Rapids in the
area of water pollution control and the methods
developed to attain and maintain high water quality
standards.
The City of Grand Rapids is the largest city in
Michigan's western lower peninsula with a population of
190,000 within the City limits and 350,000 in the
metropolitan area. The Grand River is in the heart of
Grand Rapids and is an important recreational resource
for western Michigan. Industry is highly diversified in the
metropolitan area, although Grand Rapids is perhaps
best known for its production of fine furniture. One of the
largest concentrations of electroplating firms in the
country exists in this area, with over 35 companies
engaged in this automotive-related activity.
During the late 1950's and 1960's industrial
contamination of the Grand River created severe
environmental problems. Periodic fish kills were caused
by high discharges of cyanide and heavy metals from the
metal plating industry in the area.
As the environmental movement gained momentum
during the mid-1960's, public attention in Grand Rapids
was focused on the deteriorating state of the once healthy
Grand River. The time for reversing the damaging trend
then arrived in Grand Rapids. In January of 1969 the
Grand Rapids City Commission enacted a
comprehensive Water Pollution Control (now called
Sewer Use) Ordinance, establishing effluent limitations
for cyanide and heavy metals, as well as other provisions.
Considerable effort was required to reach this point,
however. Metal platers in the area lobbied strenuously
against any limitations, arguing that the cost of
pretreatment of wastes would force them to relocate
elsewhere. City policymakers were forced to deal with
those issues and acknowledge that comparable effluent
standards did not exist elsewhere in the state.
Nevertheless, concern for the quality of the water and the
'James A. Biener, Director
Environmental Protection Department
City of Grand Rapids, Ml
general environment remained the focus, and the
Ordinance was adopted as City law.
Water pollution control is the responsibility of the City
Wastewater Treatment Plant, a division of the
Environmental Protection Department. In addition to
serving the City's wastewater disposal needs, the Grand
Rapids plant provides service to eleven cities and
townships on a contractual basis. The capacity of the
activated sludge wastewater treatment plant is currently
being expanded from 45 MOD to 90 MGD, with
assistance of an E.P.A. construction grant. Sludge
digestion is being phased out in the new design and being
replaced by a new heat treatment process. With this new
process, sludge incineration will be the principal means of
sludge disposal.
The Sewer Use Ordinance and Industrial Sewer Use
Regulations currently in effect were adopted in
substantially the same form in 1969. They set forth the
standards, rules and regulations with which industrial
users of the sewer system must comply, as well as
provisions for enforcement and management of the law.
Sewer Use Ordinance
"2.63. Management of the Sewage Disposal System.
The Grand Rapids Sewage Disposal System shall be and
remain under the management, supervision, and control
of the City Manager who may employ or designate such
person or persons in such capacity or capacities as he
deems advisable to carry out the efficient management
and operation of the System. The City Manager or his
designee may make such rules, orders or regulations as he
deems advisable and necessary to assure the efficient
management and operation of the System; subject,
however, to the rights, powers and duties with respect
thereto which are reserved by law to the City Commission
of Grand Rapids.
"2.64. Standards, Rules and Regulations. The
standards, rules and regulations established in or
pursuant to this chapter are deemed to be the absolute
minimum consistent with the preservation of the public
health, safety and welfare, to prevent pollution of the
environment, and to fulfill the obligations of the City
with respect to State and Federal law and all rules and
regulations adopted in conformance thereto. The
discharge into the System of any substance which exceeds
the limitations contained herein, or in any manner fails to
conform hereto, is hereby declared to be a public
nuisance, and a violation of this Code.
55
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"2.65. Use of the Sewage Disposal System. Any
person conforming to the standards, rules and
regulations established in or pursuant to this chapter
shall be permitted to discharge effluent into the System
provided there exists adequate sewer service available to
which he can connect.
"2.66. Prohibites Substances. Except as hereinafter
provided no person shall discharge or cause to be
discharged any of the following substances into the
sanitary or combined sewer:
(1) Any effluent having a temperature higher than 140
degrees F.
(2) Any effluent which contains more than 50 mg/1 of
animal fat, vegetable fat, oil or grease, or any
combination thereof.
(3) Any gasoline, benzene, naphtha, fuel oil or other
inflammable or explosive liquid, solid or gas.
(4) Any grease, oil or other substance that will become
solid or viscous at temperatures 60 degrees Celsius and
below after entering the System.
(5) Any substance from the preparation, cooking and
dispensing of food and from the handling, storage and
sale of produce which has not been shredded to such a
degree that all particles shall be carried freely under flow
conditions normally prevailing in the public sanitary or
combined sewer, with no particle larger than one-half
inch in any dimension.
(6) Any substance capable of causing obstruction to
the flow in sewers or other interference with the proper
operation of the sewage disposal system including but not
limited to mineral oil, grease, ashes, cinders, sand, mud,
plastics, wood, paunch manure, straw, shavings, metal,
glass, rags, feathers, asphalt, tar and manure.
(7) Any effluent pH lower than 6.0 or higher than 10.0
or having any other corrosive properties capable of
causing damage or hazard to structures, equipment or
personnel of the the treatment works.
(8) (a) Any effluent in excess of:
1.5 mg/1 of Cadmium as Cd.
6 mg/1 of Zinc as Zn.
2 mg/1 of total Chromium as Cr.
1.5 mg/1 of Copper as Cu.
1 mg/1 of Cyanide as CN.
1.5 mg/1 of Nickel as Ni.
.02 mg/1 of Phenol or derivative of Phenol.
(b) Any discharge of phosphorus, ammonia,
nitrates, sugars or other nutrients or waste
waters containing them which have an adverse
effect on treatment processes or cause
stimulation of growths of algae, weeds, and
slimes which are or may become injurious to
water supply, recreational use of water, fish,
wildlife, and other acquatic life.
(9) Any paints, oils, lacquers, thinners or solvents
including any waste containing a toxic or deleterious
substances which impair the Sewage Treatment process
or constitute a hazard to employees working in the
Sewage Disposal System.
(10) Any noxious or malodorous gas or substance
capable of creating a public nuisance.
(II) Any effluent of such character or quantity that
unusual attention or expense is required to handle such
materials at the sewage treatment plant or to maintain the
System.
(12) Any discoloration such as, but not limited to,
dyes, inks, and vegetable tanning solutions, or any
unusual chemical oxygen demand, chlorides, sulfates or
chlorine requirements in such quantities as to be
deleterious and a hazard to the System and its employees.
(13) Any radioactive wastes or isotopes of such half-
life or concentration as may exceed limits established by
applicable Local, State or Federal regulations.
(14) Any effluent containing a five (5) day biochemical
oxygen demand greater than 300 mg/1.
(15) Any effluent containing suspended solids greater
than 350 mg/1.
(16) Any effluent containing phosphorus greater than
40 mg/1.
(17) Any effluent having an average daily flow greater
than 2% of the System's average daily flow.
The Director upon review may approve discharges in
excess of the limits set forth in subsections 14 through 17
subject to conditions either set forth in this chapter or
special conditions he deems necessary in order to
preserve and protect public health, safety and welfare,
subject to conformance with the applicable State and
Federal law.
"2.67. Inspection. The Director and other duly
authorized employees of the City bearing proper
credentials and identification shall be permitted to enter
upon all properties at reasonable times for the purpose of
inspection, observation, measurement, sampling and
testing in accordance with the provisions of this chapter
and any rules and regulations adopted pursuant hereto.
Any person whoappliesforand/orreceives services from
this System under this chapter shall be deemed to have
consented to inspections pursuant to this section,
including entrance upon that person's property at
reasonable times to make inspections.
"2.68. Use of Storm Sewers. No person shall
discharge or cause to be discharged into any storm sewer
or natural or artificial water course, effluent other than
strom water or uncontaminated effluent, except with
authorization by a National Pollution Discharge
Elimination System permit, and with the approval of the
City's Director of Environmental Protection.
"2.69. Protection from Damage. No unauthorized
person shall maliciously, willfully or negligently break,
damage, destroy, uncover, deface or tamper with or alter
any structure, property, appurtenance, equipment or any
other item which is part of the Sewage Disposal System.
"2.70. Enforcement. Any person found to be
violating any of the provisions of this chapter shall be
guilty of a violation of the Code. The Director is hereby
authorized to bring any appropriate action in the name of
the City of Grand Rapids, as may be necessary or
desirable to restrain or enjoin any public nuisance, to
56
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enforce any of the provisions of this chapter, to initiate
criminal prosecution, and in general to carry out the
intent and purpose of this chapter."
Industrial Sewer Use Regulations
R-l. Industrial Cost Recovery System - All industrial
users, connected to the Grand Rapids Sewage
Disposal System, shall be required to pay their
share of existing EPA grants and any grant or
grants awarded pursuant thereto, divided by the
recovery period. All industrial users shall share
proportionately, based on flow, in the recovered
amounts. Industrial users shall also pay a
surcharge on Biochemical Oxygen Demand
(BOD) and Suspended Solids (SS) on individual
plant effluents in excess of 300 mg/1 of BOD and
350 mg/1 of SS.
R-2. Inspection - When required by the Director, the
owner or occupant of any property served by a
sewer carrying industrial or commercial waste
shall install one or more suitable control manholes
to facilitate observation, sampling and
measurement of discharges. Such manholes when
required shall be accessible and safely located and
shall be constructed in accordance with plans
approved by the Director. The manholes shall be
installed by the owner at his expense and shall be
maintained by him so to be safe and accessible at
all times, in the event that no manhole has been
required, the Director shall designate a proper
sampling point.
R-3. Testing Method - All measurements, tests, and
analyses of the characteristics of discharges shall
be determined in accordance with standard
methods, herein defined, and shall be determined
by taking suitable samples at designated sampling
points. Such sampling shall be an appropriate
manner of determining both compliance withthe
requirements and penalties specified in the
Ordinance.
The City and all users of the Sewage Disposal
System shall employ one of the following standard
methods for the analysis of effluent:
a. Standard Methods for the Examination of
Water and Wastewater, available from the
American Public Health Association;
b. American Society for Testing and Materials
(ASTM) Annual Book of Standards, Part 31;
or
c. Environmental Protection Agency Methods
for Chemical Analysis of Water and Wastes.
Users shall maintain a sampling frequency which
insures that Ordinance limitations for effluent are
met.
R-4. Industrial Surveillance Program - The City shall
sample industrial effluent entering the Sewage
Disposal System. One of two methods of
industrial surveillance shall be utilized for each
industry:
a. For those industries contributing toxic or
deleterious substances regulated and
controlled by the City Sewer Use Ordinance,
the following procedure shall be followed: A
grab sample shall be taken at the designated
sampling point.
b. For those industries contributing non-toxic
wastes exceeding amounts specified by the
City Sewer Use Ordinance, the following
procedure shall be followed: Three twenty-
four (24) hour composite samples shall be
taken at the designated sampling point during
each quarterly billing period.
Tests on all industrial surveillance samples shall be
performed in accordance with Standard Methods
for the examination of Water and Wastewater.
R-5. Penalty Charge Methods (Surcharge) - All users
of the Sewage Disposal System shall be subject to
penalty charges for effluent containing
Biochemical Oxygen Demand (BOD) in excess of
300 milligrams per liter, and Suspended Solids
(SS) in excess of 350 milligrams per liter. The City
shall collect three (3) twenty-four (24) hour
composite samples from each designated sampling
point once each billing period, and base the
surcharge cost upon such samples. The penalty
charge shall be calculated by an employee
designated by the Director and billed quarterly by
the Water Department.
R-6. Preliminary Treatment Facilities - Where
necessary, in the opinion of the Director, the
owner shall provide at his expense, such
preliminary treatment as may be necessary to:
a. Reduce the biochemical oxygen demand to
300 mg/1 and the suspended solids to 350
mg/1, or
b. Control toxic or deleterious substances, or
c. Control of the quantities and rates of
discharge of such water and wastes.
Plans and specifications and any other pertinent
information relating to proposed preliminary
treatment facilities shall be submitted for review
by the Director. No construction of such facilities
shall be commenced until the review has been
completed.
Where preliminary treatment facilities are
provided for any discharges, they shall be
maintained continuously in satisfactory and
effective operation, by the owner at his expense.
Any person required to utilize preliminary
treatment facilities shall, upon the request of the
Director, submit to the Director, records of
samplings taken from waste discharges.
R-7. Septic Tank Waste - Disposal of Sludge from
Pretreatment Systems - Sludge from an industrial
57
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or commercial pretreatment system shall not be
placed into the Sewage Disposal System. Such
sludge shall be disposed of by a licensed hauler in a
site approved by the Michigan Department of
Natural Resources.
Sections 2.63 and 2.70 designate the management
authority and legal authority necessary to implement and
enforce the Ordinance and the Regulations. Sections 2.64
and 2.65 subject all users to the provisions of the
Ordinance and the Regulations designate violations as a
public nuisance subject to penalty. Section 2.67 permits
inspection of the customers' premises by properly
authorized employees.
R-2 provides the authority to require the construction
of a sampling manhole if required. R-3 designates the
standard methods that are to be used for effluent
analysis. R-4 designates a grab sample as an acceptable
sampling procedure for toxic wastes. R-6 designates the
responsibility for construction, operation and
maintenance of pretreatment facilities. R-8 requires that
all residue sludges be disposed of in a properly licensed
site.
Initial Enforcement Program
The effluent limitations stipulated in the Sewer Use
Ordinance and accompanying Regulations required
significant changes in industrial waste disposal practices.
Local industry was required to invest several million
dollars into the design and construction of effluent
pretreatment facilities and had to provide the funds to
sustain the daily operation.
At the time of enactment of the Ordinance, the City
recognized that compliance with the limitations would.be
best achieved through cooperation between the City and
local industry. The initial step taken by the City was to
attempt to improve its already strained relationship with
industry through personal contact with representatives of
affected companies in the area, and through providing
short-term variances to those companies.
Each company was granted a two-year variance to the
Ordinance which allowed them to exceed effluent
limitations, provided that the City could determine that
satisfactory progress was being made toward
construction of a pretreatment facility. The variance
stipulated that industry must file a set of design plans
with the City for its pretreatment system within six (6)
months and submit progress reports every six (6) months
thereafter.
During the first six months of the program, City staff
visited each of the companies to meet management
personnel and to explain the details of the effluent
limitations. It was explained that the City staff would be
responsible to monitor the industrial waste on a
continuous basis and to recommend whatever legal
action was necessary to achieve compliance. The industry
was informed that we would share samples and compare
analyses at their request. The City's role was represented
as that of a "helpful guardian" of their effluent.
During the variance period it was recognized that the
effluent limitations were not achievable within the two (2)
year period and that the variance had to be extended for
six (6) months. Although industry had in most cases
made a good faith effort to meet the deadline, delivery of
pumps, motors and other electrical equipment was
slower than anticipated and was not received in time to
complete the pretreatment system in every plant. The six
(6) month extension was offered as a "shake down"
period after which active enforcement would begin.
Compliance Procedures
Following the two and one-half year variance period,
industries were subject to penalties for effluent limitation
violations. A standard procedure, outlined below, was
adopted by the City to assure uniform treatment for all
violations. While the procedure was developed with a
view towards achieving voluntary compliance, powers of
prosecution were specified to insure compliance.
1. The person responsible for a particular industry's
pretreatment system is formally notified of any
violation and directed to take immediate corrective
action. If such action is taken and is effective in
abating the violation, the City takes no further
action.
2. If any effluent limitations continue to be violated, a
complaint is filed by the City Attorney's office and a
warrant is issued by the court against the company.
3. After a warrant is issued and prior to scheduling a
trial, the company's officials and attorney are
invited to a pre-trial hearing to discuss the
company's violation and actions. If this meeting
results in commitments by the company to specific
corrective measures, the warrant is held in abeyance
until such time that effluent sampling by City staff
indicates compliance with the limitations. When
compliance is achieved, the warrant is often
cancelled.
4. If the company continues to violate the effluent
standards the warrant is sent to the court in order
for a trial to be scheduled. The company may enter a
plea up to the time of the trial.
In most cases, court trials result in convictions and
fines. Company fines usually consist of the maximum
City code penalty of $100 per violation, City costs of
surveillance and court costs. The heaviest fine levied
against a single industry was almost $5,000, representing
41 violations of the Ordinance plus City surveillance
costs. The court authorized payment directly to the
Environmental Protection Department for the
surveillance expensed involved.
A total of 212 warrants have been issued for effluent
limitation violations since 1971. Of this number
approximately twenty-five (25) percent have gone to
trial. The majority of the warrants have been resolved in
pre-trial conferences.
Collection & Disposal of Industrial Sludges
Effective control of industrial waste requires proper
collection and disposal of the residual materials resulting
58
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from pretreatment systems of industries. Sizable
quantities of both liquid and solid metallic hydroxide
sludge began to be generated in the Grand Rapids area
once the pretreatment systems became operable. The
liquid sludges were 2-6% solids and were generated by
those companies that had no physical space for
dewatering equipment or felt that liquid disposal was
more economical for them. Other companies installed
vacuum filters, centrifuges or other filtering devices to
solidify their sludges to solid contents of 20 - 30% with the
consistency of conventional vacuum filtered sewage
sludges.
Creation of industrial sludges created a local demand
for transportation and disposal of these wastes. One local
company suddenly developed- into a rather major
operation with the purchase of several large tandem
trucks for the transportation of the liquid sludges.
Another company bought some tank trucks for liquid
waste and supplied other containerized equipment for
transporting the solid wastes. This same company
constructed sand bed dewatering cells for dewatering the
liquid sludges before transporting to a disposal site.
Disposal of both the liquid and solid metallic
hydroxide sludges were under the jurisdiction of the
Michigan Department of Natural Resources. Little
attention was paid to the disposal practices, as no
specified State legislation applied and no previous
experience existed. Disposal sites were approved quite
readily by the DNR. During the first five or six years of
the industrial program, solid sludges were co-disposed
with solid waste in sanitary landfills or placed in an
approved site in an abandoned gravel pit. Liquid sludges
were dewatered in the sand bed filters of a private hauler,
or applied directly on the land at the gravel pit site.
Recently, monitoring wells located near the gravel pit
site showed a migration of heavy metals into the water
table. The site has been closed for disposal of metal
hydroxide sludges and State legislation has been enacted
to establish standards for land disposal of industrial
sludges. Co-disposal of liquid or solid metallic hydroxide
with general refuse is not allowed. Separate sites for
disposal of industrial wastes are required, and the
standards for these sites dictate sufficient clay thicknesses
that prevent any migration in either a vertical or
horizontal direction.
The present Michigan standards for industrial waste
disposal sites are very restrictive and can only be met
when the area being considered has clay depths of 25 to 30
feet. The process of evaluating an industrial disposal site
involves public hearing procedures which always result in
negative public reaction that prevents the development of
a site or at least delays the development. The process
required to license an industrial site is equal to or more
complicated than obtaining a license for a sanitary
landfill operation.
At the present time, there is no licensed site in or near
Grand Rapids for the disposal of either liquid or solid
sludges. Many companies are contracting to have their
waste hauled long distances for disposal and in most
cases to the State of Illinois or Indiana. A temporary
storage site for solid sludges has recently been approved
although the sludge must be removed from this site to a
permanent site for final disposal. The cost for
transporting and disposing of sludge has tripled or
quadrupled in the past six months because of the lack of a
local disposal site.
The present sludge disposal dilemma is not near an
end. A local site meets all the criteria of the State licensing
regulations but is being blocked by public reaction
and pressure in the township where it is proposed.
Pressure has also begun to develop from the other states
where the sludges are being deposited. We can only hope
that a disposal site or sites are developed before industry
has no choice but to dispose of its waste into the public
sewer, and we are once again back where we started in
1969.
Effects of Pretreatment Ordinance
Since adoption of the pretreatment Ordinance, there
have been significant reductions in metal concentrations
found in sewage influent and effluent. Total metal
concentration in Grand Rapids sewage is shown in
Exhibit I. Influent levels have dropped from the 12-13
mg/1 range to about 2 mg/1. Effluent levels have dropped
from the 9-10 mg/1 range to close to 1 mg/1 (representing
87% and 92% reduction respectively). Exhibit II shows
that a similar experience with total cyanide concentration
TOTAL MS7AL IV StiVACS.
0.0
59
-------
TOTAL CTAUIDC IU MM
ft « »o ii n TJ 1+ rs n TI n
TOTAL COS*f>£A
•;.' eeaucneu
60
-------
rarjt.
ny/l
"r-
10
\
The idea of non-linear removal efficiency can best be
shown by comparing the removal of each metal at the
higher influent levels of pre-ordinance to the lower
concentrations after pretreatment enactment. Percent
removals were as follows:
Cyanide
Chromium
Copper
Nickel
Zinc
Before
43% of 2.1 mg/1
35% of 5.1 mg/1
25% of 2.8 mg/1
25% of 3.2 mg/1
46% of 3.7 mg/1
After
71% of 0.14 mg/1
73% of 0.49 mg/1
63% of 0.30 mg/1
38% of 0.42 mg/1
63% of 0.78 mg/1
u ea n n u u » is r» n n
EXHIBIT VI
These figures show conclusively that higher removal
efficiencies are obtained at the lower influent
concentration. Also, as expected, nickel exhibits the
lowest removals of all in a wastewater treatment plant.
Slug discharges are common to any batch operation.
These short but very concentrated discharges can have
adverse effects on a wastewater treatment system,
particularly biological systems. Typically, treatment
efficiency is impaired for times ranging from minutes to
days. Exhibits VII and VIII show examples of large slug
discharges and the effect on treatment as measured by
suspended solids and BOD in the effluent. In each case
the concentration of metal is the average (composite
sample) concentration for the day, not the instantaneous
level which probably was an order of magnitude larger.
Prior to the pretreatment ordinance, such occurrences
were common and background levels were continuously
is even more dramatic, with reductions of 93% for
influent and 96% for effluent.
Chromium is illustrated in Exhibit III and shows
excellent reductions of 90% and 96%. Copper is shown in
Exhibit IV and has reductions of 89% and 93%. Nickel
appears in Exhibit V and shows reductions of 87% and
89%. Zinc displays erratic changes in Exhibit VI, but
shows overall reductions of 79% and 85% for the influent
and effluent respectively. Zinc is an example of
interdisciplinary effects.
In 1970, air pollution control requirements forced
brass foundaries to install scrubbers to remove zinc oxide
from their air stacks. This waste material was then
discharged into the sanitary sewer system, causing zinc
concentrations to rebound to previous levels. City staff
then focused energy on methods of achieving
pretreatment that would reverse this trend and by 1973
levels of zinc in the sewage system plummeted.
Relative reductions between influent and effluent show
that even though lower concentrations were originally
present in the effluent, higher reductions were obtained.
This was observed for all metals and cyanide. It appears
that municipal treatment plants are capable of removing
or treating low levels of metals but that efficiency
decreases with increasing influent concentration. Nickel
has often been described as the metal having lowest
removal, a view supported by our data that show the
smallest difference in improvement at two percent.
II X IS K Z
sen
i i * i
OCTO&IX <.'•
COUMT VII
61
-------
30
»— «_o A 0.9. •/ *»p/f
SOOL.
luouenot jfrtf eiuuwet trmxeeM.
fC% •* Ct/£G**IVt4
fa 7. cf cerrtt
J 6
nra
EXHIBIT VIII
higher. Currently, however, cases such as Exhibits VII
and VIII are rare.
Much of the influent heavy metal passes through
municipal treatment, but much is also trapped in the
process and removed with the sludge. Until Grand
Rapids changed to a heat treatment system, this sludge
was digested. The reason for changing was due to the
undependability of anaerobic digestion caused by
industrial chemicals.
EPA has required wastewater treatment operations to
consider other than "standard treatment" of sewage and
sludge, the end product. Land application of sludge has
become more feasible in Grand Rapids as metal content
in sludges continues to decrease, as illustrated in Exhibit
IX. The reductions average 66%, resulting in sludge that
contains only about one-third the amount of heavy metal
compared to pre-ordinance levels. Agricultural use of
sludge could prove worthwhile both in resource recovery
efforts and in reducing costs of incineration.
Water Quality Improvement
The greatest direct public benefit resulting from the
industrial waste control program has been the revival of
the Grand River. For many years, the Grand River served
as an open conduit for transporting industrial wastes
from Grand Rapids to Lake Michigan. The public
attitude toward the River was one of almost total
disrespect. Few persons used the Grand as a recreational
resource and fewer yet dared eat the fish caught from its
waters.
In 1972, the flow of industrial wastes into the Grand
had slowed to a mere fraction of its former volume. In the
Spring of that year, the Michigan Department of Natural
Resources selected the Grand as a place to stock
Steelhead Trout along with Coho and Chinook Salmon.
These fish would migrate to Lake Michigan to feed
during the summer months when the river warmed to
intolerable temperatures for these species to survive. The
Steelhead Trout return to the river to spawn in the Spring
while the Salmon begin their spawning in the Fall
months.
By 1974, the Trout and Salmon spawning runs started
to attract a lot of attention from local fishermen. Trout
weighing as much as 15 pounds and Chinook Salmon up
to 35 pounds were common catches below the dam in
downtown Grand Rapids. First a few, then hundreds of
fishermen were participating in this newly-created fishery
usually limited to northern clear water rivers. The local
Chapter of the Izaak Walton League of America
sponsored a Trout fishing contest within the City limits of
Grand Rapids to help promote our revived water
resource.
Development of the fishing in the Grand River was
only the beginning. Canoeing enthusiasts began
promoting and mapping the river as an enjoyable
canoeing adventure. Construction and improvement of
boat ramps brought more and more boating enthusiasts.
More park land was purchased by the City and was
developed into recreational areas that added important
62
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green belts along the banks of the river. Hundreds of
persons began enjoying the parks. Environmental groups
gathered together to clean the river banks of littered
debris.
In 1976, a fish ladder was constructed at the dam in
downtown Grand Rapids for the purpose of passing fish
upstream into the Grand and its many tributaries. On top
of this fish ladder a sculpture was placed that was created
by a local artist and financed by some $75,000 in local
donations. Alongside the fish ladder and sculpture there
was created a unique little park for the benefit of those
persons watching Trout and Salmon "climbing" the fish
ladder. As many as two hundred noisy participants are
often present to cheer the fish as they find their way up the
ladder.
The future of the Grand River as a recreational
resource appears to be almost unlimited. Additional
parks are being planned for development and many
recreational activities are often centered on or near the
river. The public attitude toward the Grand River has
been converted to one of appreciation and respect in just
a few short years.
63
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Selecting the Proper Unit Processes
For the Treatment of Electroplating Wastewaters
A. F. Lisanti & S. O. Megantz*
INTRODUCTION
In order to design a successful waste treatment facility
for what can be relatively complex electroplating
treatment problems, the Owner, Engineer and
Regulating Agency cannot depend upon a simplistic,
cookbook approach to the required treatment processes
and equipment. The textbook processes or prepackaged
simplified treatment units may be the optimum treatment
for a specific electroplater's operation, but that fact
should be proven before all assume it is so.
An Engineer's responsibility to the Owner and the
Regulatory Agencies is not to complicate what at times
can, in fact, be a straightforward physical/chemical
treatment process. However, he must exercise good
judgement and provide a workable system that will
achieve the desired results. We believe that such sound
judgement would require a demonstration that what is
proposed as a solution will in fact work.
This paper presents what we believe to be a proper
engineering approach to selecting unit processes for the
treatment of electroplating wastewaters. The actual work
required per project will, of course, vary dependent upon
information obtained and problems encountered. Our
experience has demonstrated that a systematic, test-the-
theory approach does result in successful projects that
achieve the desired results.
We do not imply that this is the only right way, for we
have seen successful projects that utilize the "design it big
and flexible" principle, or that hit upon constituents that
react exactly as per the textbook, and the prepackaged
process worked. The approach we present is admittedly
conservative, but it should not fail.
The first phase is the development of a preliminary
concept; this is the investigation, problem definition and
presentation of solutions. Next is the testing of the
possible solution by treatability studies, followed by
designing a custom facility. Finally, the facility must be
constructed, operators trained, and the plant
performance monitored to assure that the desired results
are achieved.
*A. F. Lisanti & S. O. Megantz
Director & Projects Environmental Coordinator
Industrial Waste Division & Real Estate/Construction Operation
The Chester Engineers, Inc. & General Electric Company
PRELIMINARY CONCEPT PHASE
The Engineers are normally engaged to conduct field
investigations and make recommendations relative to
wastewater treatment facilities to bring the Electroplater-
plant discharges into compliance with the National
Pollutant Discharge Elimination System (NPDES)
Permit or national/local government pretreatment
requirements.
The field investigations include field locating all
known discharges of wastewater. In conjunction with the
"in-plant" survey, a flow monitoring and sampling
program is conducted in the sewer systems located
throughout the plant. This information is used in the
development of a flow and pollutant mass balance for the
plant. A sampling program should also be conducted
during the peak period of plating operations. This
information is then used to develop a flow diagram of the
existing wastewaters and to establish design loadings
(both relative to flow and pollutants) for the required
wastewater treatment facilities.
Electroplating wastewaters contain a combination of
pollutants that are not compatible for practical treatment
methods. It is normal to segregate the waste stremas
relative to pollutant content so that practical treatment
methods can be employed. Therefore, the proposed
segregated waste streams should be simulated in the
laboratory for use in waste characterization and eventual
treatability studies. We believe this is necessary to assure
that each stream has compatible constituents and waste
treatment is not an unnecessary complication, for we
have all fallen victim to "end of pipe" treatment where
chromium is in alkaline streams; metals and cleaners are
combined; and oils plus solvents are everywhere.
A study of water conservation is also performed so that
the volume of wastewater requiring treatment might also
be reduced.
Concentrates are always a candidate for segregation.
The segregated waste streams can normally be divided
into six categories:
(I) Chemical Oxygen Demanding (COD) Waste
(2) Chrome Waste
(3) Cyanide Waste
(4) Acid-Alkali Waste
(5) Sanitary Sewage
(6) Non-Contact Process Water
64
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However, it is often necessary to further define the
acid-alkali waste to metal bearing, cleaners, oils, and
inert solids to achieve present effluent requirements
and/or go to wastewater recycle. If possible, the COD
waste should be directed to the sanitary sewer system
because its waste constituent composition can be
compatible to sanitary treatment. Non-contact process
waters can be recyled or discharged withoug treatment,
provided the thermal load is not a problem.
The baseline for a successfully engineered project is
water conservation and waste stream segregation.
Water Conservation
The amount of water presently used in plating rooms is
often excessive and requires conservation. Methods of
conservation should be suggested to the user and trial use
of these methods initiated by plant personnel. The
volume of wastewater requiring treatment can be reduced
significantly by employment of water conservation
procedures. This is particularly true if the existing
wastewaters resulting from the plating of metal parts are
divided into two streams: the acid waste line and the
alkaline waste line. Analyses of these waste lines often
reveal chromium and cyanide present in both lines. The
dilution of the chromium and cyanide waste with other
wastes which do not contain these parameters require
high chemical treatment dosages to meet present and
future effluent requirements.
A number of approaches can be taken to determine the
amount of water that could be saved. These can include
automatic plating machines, rinse flow control valves,
countercurrent and still rinsing. The formulae and results
of these physical changes are well documented in the
literature.
One very simplified approach we use to demonstrate
possible over rinsing involves comparison of the
dissolved solids concentrations of the acid and alkali
waste lines during different shifts. It is usually seen that
the water usage rate during "slack" periods can be
reduced to maintain a dissolved solids level equal to or
less than the active periods. Averaging the dissolved
solids concentration of each shift for each segregated line
can permit calculating the percent reduction possible.
On one project the analysis of possible flow reductions
was based upon the peak rinse tank concentrations and
areas plated determined by field studies. We were able to
demonstrate a water consumption which could be
reduced to an average of approximately 7.0 gallons per
square foot plated compared to the existing rate of
approximately 61 gallons per square foot plated. This
rate is still high when compared to EPA's guideline of
3.93 gallons per square foot. However, it was practicable
to achieve the 7.0 gallons per square foot rate. Further
reductions were just not possible because of the multiple
and varied processes employed in this plating room.
Waste Stream Segregation
Each waste is reviewed and categorized with respect to
its chemical composition. If there is a typical system, it is
one where the chrome waste consists of chromium rinses
and cooling tower blowdowns and the cyanide waste
contains all of the rinses following cyanide baths. The
acid/alkali waste generally contains all of the remaining
rinses from the plating room, which include mostly acidic
and alkaline solutions of metals. The deionizer
backwashes and deburring equipment rinses are also
included in the acid/alkali waste line. The wastes
containing COD can be considered sanitary in nature
rather than industrial and, therefore, discharge to the
sanitary sewer system if available.
Waste Character
The range of concentrations and quantities of waste
contaminants can be determined by (1) sampling and
analysis of sewer streams, (2) determining "peak"
concentrations found in each rinse water sample in
conjunction with the projected design flow, and (3)
simulating the projected wastes in the laboratory and
performing an analysis of each.
The quantities determined by the first method require a
proper interpretation of mass balance and projections.
The second and third methods can be used to project
future waste character.
The quantities found by the third method usually
represent the high end of the range. Because one may
propose to segregate the existing waste streams even
further, the projected waste streams for the treatability
studies are nomally simulated. The Engineer must rely
upon plant personnel to supply sufficient information to
undertake this task. The projected production figures for
each individual plating room tank and the results from
drag-out studies are the criteria used to establish a
baseline. By using the average daily production rates for
each tank in conjunction with an established drag-out
coefficient in ml per square foot plated, an
approximation of the average volume of concentrate
"dragged out" of each production tank into the
succeeding rinse tank is calculated. Using the projected
flow rates for the design year, calculations are made for
the volumes of concentrates required relative to the
volume of rinse water. The analyses of these wastes
represent the high range.
The mass balance approach to waste characterization
is most typical. A mass balance of the various waste
streams can be determined from data collected during a
wastewater survey program. The balance compares all
flow and constituent loads from individual sources with
the plant outfall. This approach requires engineering
judgement to assure that "bad" day and variations are
properly bracketed.
TREATABILITY
Field Treatability Studies
If the wastes are properly separated, it is often
advantageous to conduct treatability studies of the waste
lines during the field survey:
(1) The acid and alkali requirements for pH adjustment
of the alkali and acid lines can be determined first.
65
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(2) The sodium metabisulfite required to reduce the
hexavalent chrome in the acid line and waste chromium
concentrates can be measured. Various dosages of
sodium metabisulfite and varying retention times can be
evaluated.
(3) A sample of the alkali waste line can be analyzed for
amenable cyanide concentration and cyanide, if present,
can then be treated with chlorine to remove the amenable
cyanide. Various dosages of chlorine and varying
retention times can be evaluated.
The alkali and acid requirements determined in the
field or batch studies indicate several important factors
such as buffered condition of each stream, unusual usage
or reactions, potential problems, etc.
If both the acid and alkaline lines are neutral to basic,
the treatment for chromium reduction at low pH values
proves unattractive from a chemical consumption (both
acid and alkali) and total dissolved solids standpoint.
Field investigations into hexavalent chromium reduction
using sodium metabisulfite could reveal this fact. For
example, at the General Electric Waynesboro Plant,
removal of hexavalent chromium to <0.05 mg/1 Cr+6
required a sodium metabisulfite dosage of 36 pounds
NajSjOs per one pound Cr+*. Theoretical dosage for
removal is about three pounds NajSiOs per one pound
Cr*6 Because this chemical is a reducing agent, any
dissolved oxygen present in the waste also presents a
chemical demand where one pound dissolved oxygen
requires about four pounds sodium metabisulfite. This
excess use of chemical reducing agent as well as high
acid/alkali requirements indicated a need to review
alternative treatment schemes and/or collection facilities
for chromium treatment.
At the same plant, alkaline chlorination studies for the
alkaline line waste revealed that a slight improvement in
effluent quality with respect to cyanide could be obtained
by increasing contact or detention time from thirty to
sixty minutes. Improvement of treatment efficiency was
seen by increasing solution pH from 9 to 10. For
complete oxidation of amenable cyanide (below 0.05
mg/1 CN~), a dosage of 112 mg/1 Cb or eight pounds C12
per one pound CN was required. This value is
significantly higher than the theoretical requirement of
three pounds Ch per one pound Cn. This high
consumption rate is due at least in part to the fact that
caustic cleaning solution rinses are mixed with cyanide
waste streams. Further investigation into that occurrence
was warranted.
Field treatability studies are most practical when an
existing waste facility needs to be modified and
upgraded. Often one finds an existing cyanide oxidation
plant with chlorine residual and amenable cyanides in the
effluent, symptomatic of improper treatment.
Treatability studies can prescribe the solution to this
common problem.
Laboratory Treatability Studies
The laboratory is usually the best place to establish
design parameters and to test the treatment process
flowsheet. One should always consider the so called
"worst case" situation. This often removes the element of
surprise when a treatment plant is placed on-line. Typical
studies include:
(I) Chromium Reduction - Review a cross-section of
alternative treatment methods including the use of waste
concentrates. Recovery should be evaluated.
(2) Cyanide Oxidation Evaluate alkaline
chlorination which is frequently used. Design
requirements can be high variant. Electrolytic treatment
of concentrates should be considered.
(3) Quiescent Settling Determine settling rates,
flocculation requirements, sludge production, and
requirements for settling aids.
(4) Oil Treatment - Investigate acid/heat, alum/acid,
acid/alkali, etc. Soluble oil often requires the
investigation of ultrafiltration and reverse osmosis
processes.
(5) Chemical Reactions - Set proper reaction time,
agitation, and reagent quantities.
(6) Filtration Determine liquid and solids loading
rates as well as permeate quality and sludge dryness.
(7) Leachate Analyses - Measure the characteristics of
the sludge generated by treatment (now a significant
criterion).
(8) Reuse and Recovery processes.
It is not our intent to leave the impression that we are
advocating a complete spectrum of testing for all
electroplating wastewaters, although this may be prudent
for the neophyte. We believe that the skilled Engineer and
Owner will readily determine the optimum testing
required for a successful project.
One purpose of treatability studies is to determine if
the contaminants found in the waste flow can be reduced
to satisfy the requirements of the regulatory agencies.
Hopefully, the studies will be conducted prior to agreeing
upon effluent quality criteria.
Design Phase
By utilizing proper scale-up factors the Engineer can
proceed from study to design. It is usually advisable to
view a number of alternative treatment processes.
We find it helpful to develop a preliminary
performance specification for each of the major
equipment items. Vendors are requested to submit pre-
qualification information with preliminary pricing. That
information can include performance guarantees. This is
most helpful in evaluating alternative unit processes. The
alternatives should be subjected to a review by the client.
once the desired alternative is selected, then the Engineer
can prepare process flowsheets.
Desires of the user relative to degree of automation,
operating period of the plant, aesthetics,
design/construction standards, etc., must be
incorporated into the design.
Design must recognize and address the details of
chemical and solids handling, corrosion protection, fume
abatement, reliable field instrumentation, monitoring,
safety, and hydraulics to have a successful project.
66
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Construction I Start- Up
The engineering aspects of this phase require a
monitoring of equipment and installation to assure that
the design intent is not violated. We believe the
manufacturer should be relied upon to assure his
equipment is installed properly and certify that it is ready
for service. His knowledge, if properly orchestrated, can
be of great value in the successful project. This can be a
specification item to assure there is sufficient money in
the project to accomplish it.
Start-up should be performed by experienced
personnel. This period can be used as an opportunity to
train personnel that will eventually operate the facility.
Equipment and process should be tested once the
mechanical, electrical, and instrumentation operation is
satisfactory. Tests should assure that design and
guarantee conditions are achieved. Test results are often
a key input toward improved operation of a particular
facility and improved design for the next plant.
Plant performance should be monitored, for few if any
plating shops remain static with respect to wastewater
discharge; thus, new plating processes can alter treatment
performance. Ideally, the plater will consider the
consequences to the treatment facility before adopting a
new plating process.
SUCCESSFUL PROJECTS
Our engineering approach to three electroplating
operations of the General Electric Company was
essentially as outlined in this paper. However, our studies
revealed unique problems in each plant; thus, the unit
treatment processes for each plant differed. We are
convinced that a simplistic approach to each treatment
project would have failed to achieve the desired results.
Charlottesville, Virginia
The General Electric Charlottesville facility
manufactures printed circuit boards. In so doing,
wastewaters are generated from both electrolytic and
non-electrolytic plating processes. A batch type of
treatment system was recommended because of small
flows and complex wastes. The system provides for
scavenger hauling of certain bath concentrates. The
remaining bath concentrates, such as the acids, would be
metered into and blended with the rinse wastewaters for
treatment. The treatment process consists of a lime
addition to pH 11 followed by a sulfide addition and
filtration through a diatomaceous earth medium. The
diatomaceous earth filter would both remove the
precipitate and dewater the solids. The filtrate would be
neutralized with sulfuric acid to pH 8.5 before discharge.
The proposed facility meets all of the prescribed
effluent requirements except for fluorides. The
wastewater contains fluoborates, and no known practical
treatment technology exists for the removal of
fluoborates. Consequently, while the proposed system
would reduce the fluoride ion concentration such that it
would conform to the fluoride concentrations specified in
the effluent limitations, it would not remove fluoborate
ions which are analytically measured as part of the total
fluoride concentration. As a result, we suggested that
since fluoborates are stable compounds and cannot be
removed by best practical treatment technology, the
effluent limitation should differentiate between fluoride
and fluoborate ions.
Another problem was the fact that lime addition alone
did not sufficiently precipitate the copper content of the
wastewater; lime coupled with a sulfide addition was
investigated. These investigations demonstrated that by
incorporating sulfide into the lime addition process, the
copper concentration would be lowered sufficiently to
meet the proposed effluent limitations. To determine the
amount of sulfide required for this removal, various
amounts of sulfide were added to the wastewater
collected during selected copper operations and the
residual soluble copper concentration measured. These
evaluations illustrated that approximately 1.5 times the
stoichiometric amount of sulfide, based on the dissolved
copper concentration at pH 11, is required to lower the
copper concentration to less than 0.5 mg/1. Moreover,
the studies demonstrated that the sulfide addition would
not only reduce the copper concentration at an elevated
pH of 11, but also at a pH of 8.5. The fluoride ion
concentration of the wastewater, however, affects the pH
used. Although sulfide addition at pH 8.5 may be used to
precipitate the metallic constituents, at this pH value the
fluoride concentration may not be lowered sufficiently to
meet the required fluoride ion concentration.
Therefore, precipitation at pH 8.5 may not always
produce an effluent quality which would conform to the
effluent limitations.
Treatment Process
Essentially, the process consists of a batch treatment
system. Two batch treatment tanks are provided. Each
contains an agitator and each is sized to handle one day's
flow. As one tank is filling, the wastewater in the other
tank is treated and pumped to the other unit processes.
In the treatment process the concentrates that are
presently scavenger hauled continue to be disposed of by
an outside vendor. Therefore, as the baths are dumped,
they flow to a 5000 gallon storage tank prior to disposal.
The remaining concentrates that are presently dumped
into and mixed with the rinses flow by gravity to another
5000 gallon concentrate waste holding tank. At a rate of
some 200 gallons per day, these concentrates flow to one
of the two batch treatment tanks. Simultaneously, the
rinses which flow by gravity from the manufacturing
processes at about 50 gallons per minute also enter the
same batch treatment tank.
Once the wastewaters are collected in one of the batch
treatment tanks, the contents are agitated and the pH
raised to 11 with lime. This lime addition normally
amounts to about 53 pounds Ca(OH)2 per day and is
controlled by a pH assembly unit. After the lime is added,
some 6.3 pounds per day of sulfide (62.7 pounds per day
67
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TABLE 1
REMOVAL OF COMPLEXED COPPER
(AND OTHER METALS)
FROM ELECTROPLATING WASTEWATERS
Location: Charlottesville, Virginia
Lime added to pH 11
Sodium sulfide added to equivalent
sulfide ion concentration of 20 mg/I
Metal
Copper
Nickel
Lead
Zinc
Tin
Untreated
Wastewater
(mgll)
17
0.30
1.85
0.86
4.29
Treated
Wastewater
(mgll)
0.4
<0.2
<0.2
0.4
< 1.0
Na2S-9H2O) are added. The tank contents are then
analyzed for such constituents as soluble copper, tin, or
zinc. If these analyses indicate concentrations that are
acceptable for discharge, the unsettled slurry is pumped
to a diatomaceous earth pressure filter.
Prior to entering the filter, a diatomaceous earth slurry
(body feed) is mixed with the wastewater. This addition
prevents blinding of the filter and maintains an
acceptable filtration rate. Although this body feed
addition could be adjusted in the field, it is estimated that
about one pound diatomaceous earth per pound
suspended solids is in the pH adjusted wastewater. This
equates to about 29 pounds of diatomaceous earth per
day. In addition, diatomaceous earth is used to precoat
the filter. The filter is emptied and precoated once a week.
The effluent of the filter flows to an effluent tank where
under pH control, some 27.5 pounds per day of sulfuric
acid are added to adjust the pH to 8.5. The effluent of this
tank is discharged to the stream.
Since the pressure filter is designed to process a one day
flow of wastewater in a four hour period, it is not used the
remainder of the day. To prevent the diatomaceous earth
precoat from falling off during periods when the filter is
not in use, and to conserve the amount of diatomaceous
earth used in the process, a flow must be recirculated
through the filter. This flow originates at the effluent tank
and is pumped through the filter and returned to the
effluent tank. This technique permits the filter to be
emptied and precoated once a week. Consequently, at a
solids content of fifty percent some 780 pounds or 11.2
cubic feet of cake must be disposed of per week. Based on
our treatability studies, the expected effluent quality of
this treatment process is listed in Table 1.
Waynesboro, Virginia
General Electric's Waynesboro, Virginia plant is
engaged in the manufacture of data handling equipment.
There are many small cleaning and plating operations at
this plant. It afforded the best opportunity for water
conservation and waste separation. An existing
treatment plant was operating and achieving reasonable
results; however, the processes could not satisfy the new
requirements. We judged that we could utilize the
existing settling lagoons as waste equalization tanks;
other tanks could be used for waste storage. All treatment
processes were abandoned. Specific unit processes
include the following:
Chromium Reduction System
The segregated chromium wastes have a hexavalent
chromium concentration of 15 mg/1. Electrochemical
treatment with raw concentrates bled into rinses offered
the lowest combination of initial capital investment and
operating costs of any of the treatment methods
considered. Disposal of the waste chrome concentrates in
a secure landfill or evaporation in a solar evaporation
pond was not practical in terms of cost.
The electrochemical unit is commercially available,
and utilizes sacrificial iron electrodes. It produces a lesser
amount of dissolved solids than the other alternatives,
which is an asset to possible future water reuse
considerations. However, a small additional volume of
sludge will be produced because of excess iron hydroxide
formation (approximately ten pounds dry per day more
solids). This volume of extra sludge is insignificant in
terms of operating costs because of its relatively small
volume. The unit also provides slight removal of other
metals during its operation.
The unit operates most efficiently at pH values of 6 to
9. The treatability results indicated that the pH of the
waste would be in this range. However, because the
chrome concentrate is acidic, a caustic soda feed system
would be minimal. Therefore, we concluded that the
chrome concentrate could be bled into the rinse stream.
Treatment results are presented in Table 2.
TABLE 2
ELECTROLYTIC REDUCTION OF
SEGREGATED CHROMIUM (+•) WASTEWATERS
• Location: Waynesboro, Virginia
• Concentrates bled into main chromium rinse stream
• Chromium (+6) reduced electrolytically at pH 6 to 9
Untreated
Wastewater
Parameter
Chromium f)
13.7
Treated
Wastewater
(mgll)
<0.05
Cyanide Oxidation System
The concentrates amounting to fifty gallons per day
(gpd) and containing 36,000 mg/1 CN "A" are treated in
an electrolytic destruction unit and then bled into the
rinse system.
In comparing all of the alternative treatment schemes,
68
-------
the treatability results revealed only small differences in
the amount of amenable cyanide left with that remaining
in the alkaline chlorinated effluent after thirty minutes of
single stage oxidation. The concentration of total cyanide
was higher when the treated cyanide concentrate was bled
into the rinse stream before chlorine oxidation. However,
after mixing the treated total cyanide wastes with the
other wastes and raising the pH, the total cyanide
concentration met effluent limitations.
Treatment results are set forth in Table 3.
TABLE 3
TREATMENT OF CYANIDE WASTEWATERS
Location: Waynesboro, Virginia
Amenable cyanides in concentrated solutions
electrolytically oxidized
Oxidized concentrates bled into main cyanides stream
for conventional oxidation by chlorination
Untreated Treated
Concentrates Concentrates
Treated
Blended
Stream
Parameter
Total Solids
Total Cyanides
Amenable
Cyanides
(mgll)
284,380
38,400
36.000
(mgll)
200.900
1,260
<0.05
0.35*
•Upon precipitation and solids removal this reduces to<0.05 mg/l.
Combined Waste Treatment System
Initial treatability results showed that the pH must be
raised to about 11.0 for sufficient precipitation of metal
hydroxides to meet effluent limitations for metals (nickel,
in particular). Also, phosphorus (that is, ortho-
phosphate) removal was enhanced at this high pH value.
The data in Table 4 shows the beneficial effects of
polishing filtration at a pH of 11 on metals removal and,
in particular, the enhancement of nickel removal. This
led to the inclusion of polishing filtration in the treatment
process.
The data in Table 5 shows the quality of wastewater
containing treated chromium and cyanide wastes when
filtered at a pH of 9.5. Orthophosphate removal was
satisfactory but zinc and nickel concentrations were at
borderline values. It was concluded that good pH control
in the 9.5 to i 1 range would be required to minimize lime
consumption and to achieve the necessary heavy metals
removal.
Our studies indicated that lime requirements and
sludge production would be significant. These problems
prompted additional study.
To improve upon the initial recommended treatment
system and to decrease the volume of sludge to be
disposed of, a sludge dewatering study was performed.
This consisted of clarifying the combined wastewater and
gravity thickening the sludge with 2 mg/l of coagulant aid
TABLE 4
REMOVAL OF COMPLEXED NICKEL
(AND OTHER METALS)
FROM COMBINED
ELECTROPLATING WASTEWATERS
EFFECT OF POLISHING FILTRATION
Location: Waynesboro, Virginia
Lime added to pH II
Solids removed by settling,
then filtration through diatomaceous earth
Parameter
Copper
Nickel
Total Chromium
Zinc
Tin
*N.D. = not detected.
Settled Waste Filtered Waste
(mg/l) (mgll)
0.41
1.3
0.14
0.14
1.0
0.29
0.10
N.D.*
0.04
N.D.*
TABLE 5
REMOVAL OF COMPLEXED NICKEL
(AND OTHER METALS)
FROM COMBINED
ELECTROPLATING WASTEWATERS
EFFECT OF TOTAL TREATMENT
Location: Waynesboro, Virginia
Lime added to achieve pH 9.S
Solids removed by settling,
then filtration through diatomaceous earth
Untreated Waste
Parameter
Nickel
Iron
Copper
Zinc
Ortho-Phosphate
7.2
7.6
1.12
2.9
12
Treated Waste
(mgll)
0.5**
0.32
0.13
0.04
0.01
* This waste contains previously reduced chromium (+*).
Amenable cyanides were previously oxidized.
••Other studies showed concentration reductions toO. I mg/l by
increasing pH to 11. See Table 4.
added prior to mechanical dewatering by use of a filter
press.
It should be noted that this sludge comprised the total
solids to be disposed of because the solids (and
diatomaceous earth) from the pressure filters used to
polish the clarifier overflow were also fed to the gravity
thickener.
Gravity thickening increased the solids concentration
of the clarifier sludge from one to two percent by weight.
The filter press dewatered the thickened sludge at a rate
of 3.7 gallons per hour per square foot with a cycle time of
one hour and produced a sludge cake containing thirty
percent solids.
69
-------
Filtration rates in pressure filters used to polish
clarifier overflows are high when compared with presses
in sludge filtration service. The rates decrease markedly
as a significant cake thickness (1/16 inch) builds up in the
filter. The final design filtration rate for pressure filters in
this type application has been found to be about 0.5
gallons per minute per square foot of filter area. When
the filter reaches this rate, the cycle is terminated and the
cake is discharged. This study indicated that a cycle
period of eight hours is reasonable. The resulting cake
thickness would be about one-fourth inch, including one-
eighth inch precoat.
TABLE 6
ANALYSIS OF EFFLUENT
Untreated
Combined pH Adjusted
pH
Alkalinity to PHT.
mg/1 CaCOi
Alkalinity to M. O..
mg/1 CaCO.
Acidity to PHT.
mg/1 CaCOi
Acidity to M. O..
mg/ 1 CaCOi
Total Solids
Suspended Solids, mg/1
Dissolved Solids, mg/1
Iron, mg/1 Fe
Manganese, mg/1 Mn
Nickel, mg/1 Ni
Copper, mg/1 Cu
Hexavalent Chromium,
mg/1 Cr
Total Chromium.
mg/ICr
Zinc, mg/1 Zn
Lead, mg/1 Pb
Tin, mg/1 Sn
Cadmium, mg/1 Cd
Fluoride, mg/1 F
Total Phosphorus,
mg/1 P
Ortho Phosphorus, mg/1
mg/lP
Hydrolyzable
Phosphorus, mg/1 P
Total Cyanide, mg/1 CN
Amenable Cyanide,
mg/1 CN
COD, mg/1
Total Organic Carbon,
mg/lC
•After chromate reduction
Wastewater
Mixture*
5.9
94
340
1220
24
1196
7.4
1.4
8.0
3.2
0.00
1.46
3.05
O.I
0.9
0.01
10.0
16.4
11.5
13
1.3
0.00
58
29
and cyanide oxidation.
Effluent
9.0
12
70
1350
1
1349
0.33
0.02
0.10
0.38
0.00
0.04
0.06
-------
Erie, Pennsylvania
General Electric's Erie plant is engaged in the
manufacture of locomotives, electric motors, and
aerospace components. Supporting these operations are
various plating operations; various metal parts cleaning
and processing facilities; foundry operations; and an
electric power station. This paper addresses the plating
and cleaning operation.
This plant contains many individual manufacturing
operations and waste sources spread throughout the site
in individual buildings. The building survey located all
discharge point sources within the manufacturing
facilities. In general, most point sources in the plant have
small flow rates, but their contaminants may vary from
mild cleaning solutions to concentrated pickling and
plating wastes. Because most of the flows are small, it
may appear feasible to treat the wastes at their sources
before they are discharged. Closer examination showed
this is not economical. To treat each point source would
in effect require a "mini" treatment plant at each source,
or at the very least some type of batch treatment in the
processing tank. It proved more economical to discharge
to the proposed treatment system and treat compatible
wastes in one single operation. There was some savings
that was realized by reducing the waste volume to the
treatment plant. By the use of countercurrent rinses and
flow control valves, flows were reduced by 30,000 gallons
per day.
After considering a number of alternatives, we decided
to collect the concentrated and dilute oil-alkali
wastewater in the existing concentrated oil-alkali
collection system. The plating waste along with the other
general plant wastes would be collected in the existing
acid bearing wastewater collection system. This
approach significantly reduced collection costs as
compared with the separate collection of each waste.
Separate collection would have allowed more efficient
treatment of each category of waste collected but, in this
case, this did not offset the high capital cost of achieving
the separation.
The user requested that the treatment processes be
designed for a fourteen hour per day operation. Design
flow rates for the various waste waters are set forth in
Table 9.
TABLE 9
DESIGN WASTEWATER FLOW RATES
Description
A. Cyanide Bearing
B. Concentrated and Dilute Oil-Alkali
C. Metal Bearing (Plating)
D. Contaminated Storm Flow (90,000
gallons treated over two days)
Total
Gallons per dav
(gpd)
140.000
156,000
457.000
753.000
45,000
798,000
TABLE 10
REMOVAL OF INSOLUBLE OILS
FROM SEGREGATED WASTEWATERS
Location: Erie, Pennsylvania
Lime added (500 mg/l) in two stages
with settling after each stage
Parameter
Oil and Grease
Cadmium
Chromium
Copper
Zinc
•After second stage.
Untreated waste
(mgll)
392
0.55
0.87
0.93
0.68
Treated waste*
16
<0.05
O.I2
<0.05
<0.05
Oil-Alkali Waste Treatment
Both the concentrated oil-alkali waste and the more
dilute oil-alkali rinse waters are discharged to one of the
existing 75,000 gallon waste treatment holding tanks.
Pumps transfer the oil-alkali waste from the holding tank
to a flash mix tank. The first step in the oil-alkali
treatment sequence is that of flash mixing the waste with
lime.
Lime is added in the first flash mix tank at a rate
controlled by pH. With the pH adjusted to about 10 and
with the proper amount of lime added, the waste flows by
gravity to an oil-solids separator. The separator is sized
to allow for the oil laden solids to settle to the bottom of
the unit by gravity. Any free oil which floats to the top of
the unit will be skimmed and transferred to an oil holding
tank. The treated liquid enters a second flash mix tank
where lime is again added at a dosage proportional to the
first flash mix tank addition. The effluent from the
second flash mix tank overflows to a second oil-solids
separator, similar to the first unit for final separation of
the oily solids from the liquid.
The effluent from the final separator discharges to a
wastewater blending tank. In the blending tank it is
combined with other waste streams and the combined
streams are treated with lime for pH adjustment. The
plant is designed to keep an even flow of this high pH
treated oil-alkali waste to the waste blending tank. The
mixing of this high pH waste with the other acidic wastes
causes the resultant mixture to have an overall alkaline
condition. Fresh lime then needs to be added only to trim
the pH within a range of 8 to 9. Typical treatment results
for the oil removal process are presented in Table 10.
The oil laden solids thicken to a sludge in the bottom of
each separator. These sludges can be recycled back to the
flash mix tanks to promote flocculation or can be
directed to a sludge thickener for additional thickening.
Plating and General Plant Waste Treatment
Wastewater generated in the various plating
operations and general plant wastewater are pumped to
an existing acid brick lined holding tank agitated by an
71
-------
TABLE 11
QUALITY OF COMBINED
TREATED WASTEWATERS
• Location: Erie, Pennsylvania
• Wastewaters combined after treatment: cyanide bearing,
electroplating, insoluble oil bearing, contaminated
storm water
Parameter
TSS
Oil and Grease
Iron
Copper
Chromium
Chromium"'
Zinc
Cadmium
Amenable Cyanide
Nickel
Concentration (mg/l)
In Combined Treated Effluent
Daily Average Values
<20
l.O
0.5
0.5
0.05
0.5
0.3
<0.05
0.5
air mixing system. From the holding tank, the waste is fed
to a chromium reduction tank where sulfuric acid is
added by automatic pH adjustment. The waste in this
tank is monitored for pH and ORP (Oxygen Reduction
Potential). As the ORP increases, indicating the presence
of hexavalent chromium, sodium bisulfite is
proportionally metered to the waste. Following the
reduction of chromium in the tank, the waste flows to the
wastewater blending tank (the same one to which the
treated oil-alkali waste flows). Lime is added to this
blending tank and to a following neutralization tank to
trim the pH to achieve maximum precipitation of metal
hydroxides. Sodium sulfide is also added to the
neutralization tank at a constant rate (O-IO ppm S=). The
addition of the sodium sulfide is designed to provide for
additional metals removal. The majority of the metals
will be removed as a result of precipitation of metal
hydroxides. This formation results from the adjustment
of the waste's pH. At this alkaline pH the presence of
sulfide will further lower the solubility of metals through
the formation of metal sulfide precipitants. Sulfide
treatment has been found helpful for metals removal to
achieve required effluent quality limits. From the
neutralization tank the waste flows by gravity to each of
two liquid-solids separators.
Prior to entry to the separators, the neutralized waste is
dosed with coagulant aid in flash mix/flocculation
equipment. Coagulant aid concentration is in the range
of 0.5 to 2.0 mg/1. The flash mix and flocculation system
is provided to properly dispense and aid and enhance
formation of settleable flocculated particles. The
separator units are designed to allow gravity settling of
the metal precipitates which are suspended. A liquid-
solids mixture first enters the separator. The suspended
solids in the mixture will settle to the bottom of the unit
allowing for a constant decanting of the mother liquid at
the top of the unit. The settled solids (sludge) are pumped
to a sludge thickener (the same thickener in which the oil-
laden solids are thickened). A second sludge pump will
return, or recycle, sludge to the blending tank to improve
the sludge characteristics and lower the demand for lime.
The difference between a conventional clarifier and the
liquid-solids separator is basically in the reduced land
space requirement of the proposed unit. Both units
perform the same unit process treatment of liquid-solids
separation.
The clarified effluent (overflow from the separators)
then flows from each separator to a water reuse basin.
From there it is mixed with the treated cyanide bearing
wastewater.
The final plant effluent is monitored to determine both
the quality and quantity of the effluent flow. Some of this
water is recycled for operations such as making lime
slurry. A secondary function of the final basin is to
ensure, through the use of an oil baffle, that free oil is not
discharged from the system. (Table II.)
Cyanide Bearing Waste Treatment
The existing cyanide treatment facilities provided three
tanks used for holding or treating incoming wastes.
Cyanides were treated in batch fashion, and discharged
after settling to reduce suspended solids. The
modifications included the use of sodium hydroxide in
lieu of lime, the addition of automatic pH and chlorine
feed instrumentation, and clarification by means of a
tubular cloth media filter prior to discharge, rather than
settling.
The treatment of cyanide waste is a batch process.
Each batch is analyzed for cyanide prior to discharge.
After the laboratory check, the tank of treated waste is
pumped under flow control provided by a flow control
valve to the filter. The filter removes practically all
suspended solids in the waste thereby rendering it
acceptable for final pH adjustment and discharge. The
solid waste removed by the filter is discharged to the
sludge thickener. (Table 12.)
TABLE 12
DESTRUCTION OF AMENABLE CYANIDE
IN CYANIDE WASTEWATERS
• Location: Erie, Pennsylvania
• Sodium hydroxide added to pH 9.5
• Chlorine added to oxidize cyanides
• Solids removed by small tubular filter
Parameter
TSS
Amenable Cyanides
Total Cyanides
Untreated
Wastewater
(mg/l)
7.3
7.9
Treated
Wastewater
(mg/l)
<0.05
0.6
72
-------
TABLE 13
PLANT FILTER PRESS PERFORMANCE DATA
Location:
Percent Solids in Sludge
to Filter
Cake Thickness (inches):
Percent Solids in Cake:
Filtration Rate:
Erie, Pennsylvania
2 to 4 percent
3/l6to3/4
22% to 30%
3 to 5 gph/sq ft to 2 Ib/hr/sq ft
Sludge Dewatering Facilities
Sludge generated in the treatment of the various
wastewaters is directed to a gravity sludge thickener.
Because of the low solids loading rate, the sludge is well
concentrated in the thickener. The concentrated sludge is
removed from the thickener and pumped to a filter press.
The filter press can also receive feed from pumps installed
on the oily sludge tank. Sludge pumps controlled by the
filter process transfer thickened sludge to the press until
the head loss across the filter reaches a preset level. At
that time the pump stops. The operator can then start the
filter in its solids cake discharge cycle. After the solids
have been removed from the press, the operator starts the
press in a new filtration cycle. The filter has been sized to
operate for one shift per day. To ensure proper filtering
characteristics, a diatomaceous earth precoat system is
included. We anticipated that when very oily sludge is
being processed, the filter would first be precoated; to
date, this procedure has not been necessary. Tests have
shown that other filtration aids such as polyelectrolytes
are not needed for this waste.
The solids cake discharged by the filter presses is put in
steel bins. When full, the bins are individually trucked to
a landfill. (Table 13.)
Soluble Oil Treatment and Reclamation
Waste soluble oil is collected at various locations
throughout the plant site. The majority of the oil is
pumped to a central storage tank. Several distant points
are trucked to storage. The soluble oil waste is then
pumped to the treatment plant site.
Three soluble oil treatment tanks are used to collect
and treat this waste. One tank is normally available to
accept untreated waste oil. When it is filled, the tank is
then allowed to stand idle to allow the waste to undergo
quiescent settling of suspended solids and allow free oil to
float to the surface. During this settling time, the free oil
is continuously removed from the surface by a rope type
oil skimmer. After settling, any sludge which is deposited
in the tank's bottom cone is pumped to the oily sludge
holding tank. Following this preliminary treatment,
prior to ultrafiltration, the tank contents are heated using
steam to about 100 degrees F.
The heated waste is then recirculated through an
ultrafiltration (UF) unit by a high pressure pump (one
running/one standby spare) for treatment. As the soluble
oil passes through the UF unit, water passes through the
filtration membrane and the remaining fluid, now of a
higher oil concentration, is returned to the treatment
tank. This process continues until the original batch of
waste oil is concentrated to about 40 percent oil. The UF
unit has a nominal design of 4000 gallons per 24 hour day.
The filtration process is automatic. The unit operates
until a preset headloss across the UF unit is obtained.
Oversized storage tanks are designed to ensure a
maximum filter run. If the UF unit reaches its preset
headloss before the majority of stored waste oil is
properly concentrated, the partially concentrated oil
would be diluted with virgin waste oil and again filtered.
In this manner maximum usage of the UF unit is assured.
When properly treated, the concentrated oil is
transferred to oil storage tanks. The UF unit is then
cleaned using a system which employs a detergent
cleaning solution circulated through the unit. Following
cleaning, the unit is available for another batch of waste
oil. Sizing of the UF unit is for three days per week
operation. Liquid filtered from the waste soluble oil can
be discharged from the unit through an effluent
monitoring pit or direct to the sanitary sewer.
Based on the design figure of 12,000 gallons per week,
the concentrated oil is reduced to about a volume of 600
gallons per week. In addition to de-emulsifying the
TABLE 14
REMOVAL OF "SOLUBLE" OILS
FROM SEGREGATED WASTEWATERS
• Location: Erie, Pennsylvania
• Soluble oils removed by ultrafiltration
• Permeate to sanitary sewer
• Concentrate to boiler fuel
Parameter
TSS
Phenols* (avg)
Oil and Grease
Untreated
Waste
(mgll)
400 to 2200
21.4
2000 to 17,000
Permeate
(mgll)
\ to 355
7.5
300 to 700
Concentrate
10,000 to 40,000
106
250,000 (avg)
*As mg/l of phenol.
TABLE 15
EFFLUENT QUALITY ULTRAFILTRATION
PERMEATE SOLUBLE OIL TREATMENT PLANT
Parameter
Flow, ~ 12,000 gal/wk
Flow, ~4,000 gal/day
gpd
PH
Phenols
Suspended Solids
Petroleum Based Oils
Animal & Vegetable
Based Oils
Daily Average (3 days I week)
Ib/day
0.5
10
0.17
20
6-9
15
300
5
600
73
-------
soluble oil to a concentrated oil form, the UF unit also
causes the concentrated oil to become amenable to
further concentration through acidification.
Reclamation of the oil concentrated by the UF unit
process is proposed. The concentrated oil which is stored
at another location would be periodically transferred by
truck to the soluble oil treatment facilities. The oil would
be placed directly into an existing concrete treatment
tank now used for soluble oil acidulation. Using the
existing mixer, the tank content pH would be adjusted to
about 2 with sulfuric acid. Sulfuric acid could be added
manually from acid carboys. After proper mixing, the oil
would be allowed to stand, at which time an oil/water
phase separation would take place. At this point an oil
TABLE 16
PROCESS WASTEWATER TREATMENT FACILITIES
AVERAGE EFFLUENT ANALYSES
Daily Average per Month (77/78)
Constituents
Suspended Solids, mg/l
Oil and Grease, mg/l
Total Copper, mg/l
Cadmium, mg/l
Total Chromium, mg/l
Chromium, mg/l Cr*
Total Iron, mg/l
Zinc, mg/l
Total Aluminum, mg/l
Nickel, mg/l
PH
Number of Samples
Permit Limits
20
10
0.5
0.3
0.5
0.05
I.O
0.5
0.5
0.5
6- 10
November
33. 1
9.5
0.52
O.I2
0.08
0.0 1
0.6 1
0.22
O.I6
0.07
9.2
24
December
I9.9
5.4
0.4 1
O.I3
0.08
0.02
0.55
0.22
O.IO
O.IO
9.0
25-27
January
1 7.9
7.0
0.48
0.13
O.I3
0.0 1
0.67
0.29
<0.l
0.07
8.9
30
February
26.9
9.5
0.37
O.I4
0.16
0.02
0.68
0.35
O.IO
O.I6
9.0
20
TABLE 17
PROCESS WASTEWATER TREATMENT FACILITIES
EFFLUENT COMPOSITE ANALYSES
Daily Average (1/1/79 thru 1/6/79)
Constituents
Suspended
Solids, mg/l
Oil & Grease,
mg/l
Tot Copper,
mg/l
Cadmium.
mg/l Cd
Tot Chromium,
mg/l
Chromium,
mg/l Cr*
Total Iron,
mg/l Fe
Zinc, mg/l Zn
Tot Aluminum,
mg/l Al
Nickel, mg/l Ni
PH
Row
Permit Limits
20
10
0.5
0.3
0.5
0.05
1.0
0.5
0.5
0.5
6- 10
I/I
1.0
1.8
0.00
0.04
0.07
0.01
0.40
0.04
0.45
0.04
9.3
188,400
H2
17.5
1.6
0.15
0.01
0.03
0.00
0.27
0.04
0.31
0.05
7.3
502,200
113
7.5
4.0
0.13
0.11
0.04
0.00
0.31
0.04
0.23
0.06
8.9
492,300
1/4
8.0
3.0
0.29
0.03
0.03
0.00
0.43
0.04
0.23
0.02
8.9
369,200
1/5
4.0
1.6
0.22
0.04
0.08
0.00
0.77
0.07
0.21
0.12
9.3
662,800
1/6
5.5
3.6
0.14
0.03
0.05
0.00
0.63
0.07
0.39
0.07
8.7
192,500
74
-------
decant pump would transfer the floating layer of oil to the
existing elevated storage tanks. The oil would now be
concentrated to about 80 percent oil, 20 percent water.
The lower layer of water remaining in the treatment tank
would be pumped to one of the soluble oil treatment
tanks for reprocessing.
The oil-free wastewater from the UF unit is discharged
to the City of Erie's sanitary sewer system. (Tables 14 &
15.)
The start-up of the treatment facility demonstrated
that our engineering approach was justified. Table 16
presents the operating results during the four initial
months of operation. This demonstrates some less than
desirable results which could be attributed to treatment
techniques. However, we were well pleased that the plant
achieved a high level of compliance with effluent criteria
during the start-up period.
The treatment plant has been on-line for more than one
year and performance is in compliance with permit
requirements. Table 17 presents the latest treatment
results.
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Federal Financial Assistance For Pollution Abatement
Sheldon Sacks*
I want to discuss the various important financial
assistance programs that you should keep in mind when
determining which route to pursue in financing your
industrial pollution control equipment needs or advising
clients on financing alternatives.
I would like to mention to you the tax considerations in
regard to pollution control devices from certain sales, use
and property taxes that allow the companies to use tax-
exempt financing for their pretreatment expenditures.
Such programs permit a company to pay lower taxes.
Income Tax Provisions—
(Two Alternative Tax Treatments)
Rapid Tax Amortization & Investment Tax Credit
Businesses installing pollution control equipment
currently may choose between two methods of income
tax treatment. Under the first alternative, the
corporation chooses to depreciate the pollution control
equipment over its taxable income each year for the
useful life of the equipment, using any IRS-approved
depreciation method, such as straight-line, sum-of-the-
years-digits, or declining balance. In addition, the
company is allowed to take an investment tax credit of
10%, but the credit may not exceed total tax liability, or
$25,000 plus 50% of the tax liability in excess of $25,000,
whichever is less. Should the allowable amount result in
unused credit, this excess may be carried back to the 3
preceding tax years, and the balance still unused in those
years may be carried over to the 7 succeeding tax years.
The unused credit must be used in the earliest of these
years and absorbed to the extent allowed. To qualify for
the full investment credit, the property or equipment
acquired must be depreciable, have a minimum three-
year useful life, be a tangible, integral part of the
enterprise's operations, and be placed in operation
during the year for which the credit is sought. Structures
built to house a necessary component or which are part of
a component qualify for credit, although a structure built
to provide shelter alone ordinary does not qualify for
credit. Related mechanical equipment also is eligible even
if located physically apart from the business seeking the
tax credit.
Under the second alternative tax treatment, the firm
'Sheldon Sacks, Financial Assistance Coordinator
EPA Office of Analysis & Evaluation
Washington, DC
may elect to take advantage of the special rapid
Amortization of Pollution Control Facilities through
Section 169 of the Internal Revenue code. The provision
was introduced in 1969 to encourage private enterprise to
cooperate in efforts to cope with the problems of
industrial pollution.
Section 169 applies to a "certified pollution control
facility." This is defined to be a facility completed or
acquired after 1968 as a "new identifiable treatment
facility which is used in connection with a plant or other
property in operation before January 1, 1969, to abate or
control water or atmospheric pollution or contamination
by removing, altering, disposing, or storing of pollutants,
contaminants, wastes, or heat, and which has been
certified by the state and Federal pollution control
authorities as being in conformity with applicable state
and Federal regulations. In the case of a treatment facility
used in connection with a plant not in operation before
1969, but in operation before 1976, only a portion of the
investment may be rapidly amortized. Thus the rapid
amortization provision is clearly intended to aid
relatively older manufacturing operations.
In addition, eligible equipment must not significantly
increase the output or capacity, extend the useful life or
reduce the total operating costs of the plant or other
property, nor must it alter the nature of the
manufacturing or production process.
If the facilities qualify as outlined above, the taxpayer
is allowed to recover the costs over a 60-month period,
instead of over the longer period provided in Section 167.
This 60-month amortization deduction is limited to
facilities with a useful life of no more than 15 years, or
that fraction of the basis of a facility with other
accelerated depreciation provisions found in the code.
However, in addition to taking advantage of the rapid
amortization provision, the taxpayer may also take
advantage of half of the investment tax credit, or 5%, in
the year in which the eligible equipment is purchased. As
with the 10% credit, the same limitations to the credit
allowable in any one year applies. In addition, the credit
applies only to equipment with a useful life of at least five
years.
Thus, if $100,000 of new facilities were acquired, the
taxpayer could claim an investment credit of $5000. This
amount would be a direct credit against current income
taxes.
Rapid amortization is attractive only at very high
discount rates or in cases where the equipment would
otherwise have a useful life greater than twelve years.
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Useful Life
Under 3 years
3 yrs. or more but less
than 7 yrs.
5 yrs. or more but less
than 7 yrs.
7 yrs. or more
percent of Cost of
Properly Qualifying for Credit
0
33 1/3
662/3
100
Aside from the tax angles for pollution control there
are various Federal Financial assistance programs to
help ease the cost of pollution control. The Pollution
Control Loan Program was provided for in Section 8 of
the FWPCA Amendments of 1972 (92-500) titled "Loans
to Small Business Concerns for Water Pollution Control
Facilities" and authorizes loans to assist small businesses
in adding to or altering their equipment, facilities or
methods of operation in order to meet the Water
Pollution Control requirements established under the
FWPCA. EPA must certify to SBA that the equipment is
necessary and adequate to meet their pollution control
requirements.
The loan program comes under the SBA Economic
Injury Loan Program and during the past fiscal year 180
million dollars was appropriated for the direct loans.
An "economic injury loan" is a loan based on a
hardship caused the business as a result of government
regulation, namely pollution control requirements, etc.
The economic injury loan program is made up of water
and air pollution control requirements, coal mine, health
and safety, occupational safety and health, emergency
energy shortage loans, consumer protection loans, etc.
To date we have loaned out roughly fifty million
dollars with the average loan being 125,000. Roughly one
quarter of the loans thus far have been to electroplaters,
the direct interest rate is 73/8% and may extend for up to
thirty years. Loans are made to concerns who are likely to
suffer an economic injury without them: a turn down
from a bank, however, is necessary in order to get the
loan. (In cities with over 200,000 people, two turndowns
from a bank are required.)
The loan turndown, however, may take any of a
number of forms. The interest rate may be too high, the
bank may require a very short payback period or the
bank may require more collateral than can be met by the
applicant. The bank may not want to loan that much
money for a non-productive venture.
There are participation loans and guaranteed loans
with SBA and commercial lending institutions, but these
rates are considerably higher (participation 10!4,
guaranteed loans 1114%), than the direct loans.
Eligibility and Purpose of Loan
1. The business has an effluent discharge requiring an
NPDES permit. The permit is in essence a contract
between a discharger and the government. It regulates
what may be discharged and how much. It sets specific
limits on the effluent from each source.
2. The business emits discharges through a sewer line
into a publicly owned treatment works, and the city or
town requires pretreatment of the waste discharge, (The
applicant must submit the municipal permit number and
receive from the municipal POTW a statement detailing
the specific pretreatment requirements.)
3. The business plans to discharge into a municipal
sewer (307) system through the construction of a lateral
or interceptor sewer.
4. The business is subject to the requirements of a
State or regional authority for controlling the disposal of
pollutants that might affect groundwater.
5. The business is subject to a Corps of engineers
permit for disposal of dredged or fill material into
navigable waters of U. S.
6. The business is subject to Coast Guard or State
requirements (312) regarding the standard of
performance of marine sanitation devices controlling
sewage from vessels. All regulated vessels will be required
to install a certified device or otherwise meet EPA
standards by January 30, 1980.
7. The business is implementing a plan to control or
prevent the discharge or spill of oil or other hazardous
substances. (Stores oil greater than 1320 gallons above
ground and 42,000 below.) (Section 31U of P. L. 92-500)
SBA DEFINITIONS OF A SMALL BUSINESS
IN THE METAL PRODUCTS
MANUFACTURING INDUSTRY
The Small Business Administration (SBA) has
developed definitions of a small business which can be
used by the SBA when granting loans. Other definitions
have also been developed by SBA to be used throughout
the federal government for such programs as small
business set-aside contracts. Both definitions are
expressed in terms of either number of employees or
dollar sales volume, depending on the industry; the
maximum size allowed for inclusion in the small business
category also depends on the industry and varies
considerably. For metal products manufacturers (all of
which are a part of the 34 thru 39 series of the government
Standard Industrial Classification system, of SIC code),
the definitions are in terms of number of employees.
SBA defines "number of employees" as:
the average employment of any concern including
the employees of its domestic and foreign affiliates,
based on the number of persons employed on a full-
time, part-time, temporary, or other basis during the
pay period ending nearest the last day of the third
month in each calendar quarter for the preceding
four quarters.
In other words, the number of employees for companies
with seasonal employment is not based on the peak
number. The number is an average based on the actual
number at four quarterly intervals during the preceding
year.
In addition, a company that conducts its business in
more than one SIC must determine an employee size limit
based on weighted averages. The percentage of business
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performed in each SIC is multiplied by the number
associated with the SIC and the results totaled for each
SIC.
The accompanying Table for the metal products
manufacturing SICs lists the specific company size
standards used by SBA when granting loans.
TABLE I
METAL PRODUCTS MANUFACTURING SICs
Census
Classification
Code
Industry or Class of Products
Census
Classification
Code
Industry or Class of Products
Employment
Size Standard
(number of
employees)
3444 Sheet metal work
3484 Small arms
3482 Small ammunition
3493 Steel springs, except wire
3494 Valves and pipe fittings, except
plumbers' brass goods
3495 Wire springs
Major Group 35: Machinery, Except Electrical:
Employment
Size Standard
(number of
employees)
250
1,000
1,000
500
500
250
Major Group 34: Fabricated Metal Products, Except Machinery and
Transportation Equipment:
3483 Ammunition, except for small 1,000
arms, n.e.c.
3446 Architectural and ornamental
metalwork 250
3465 Automotive stampings 250
3452 Bolts, nuts, screws, rivets, and
washers 500
3479 Coating, engraving and allied
services, n.e.c. 250
3466 Crowns and closures 250
3421 Cutlery 500
3471 Electroplating, plating, polishing,
anodizing and coloring 250
3431 Enameled iron and metal sanitary
ware 750
3499 Fabricated metal products, n.e.c. 500
3498 Fabricated pipe and fabricated
pipe fittings 250
3443 Fabricated plate work (boiler
shops) 250
3441 Fabricated structural metal 250
3423 Hand and edge tools, except
machine tools and handsaws 250
3425 Handsaws and saw blades 250
3429 Hardware, n.e.c. 250
3433 Heating equipment, except elec-
tric and warm air furnaces 500
3462 Metal forgings and stampings 500
3411 Metal cans 1,000
3442 Metal doors, sash, frames, mold-
ing and trim 250
3497 Metal foil and leaf 500
3412 Metal shipping barrels, drums,
kegs, and pails 500
3469 Metal stampings, n.e.c. 250
3496 Miscellaneous fabricated wire
products 250
3449 Miscellaneous metalwork 250
3463 Nonferrous forgings 250
3489 Ordnance and accessories, n.e.c. 250
34332 Plumbing fixture fittings and trim
(brass goods) 500
3448 Prefabricated metal buildings
and components 250
3451 Screw machine products 250
3563 Air and gas compressors 500
3585 Air conditioning and warm air
heating equipment and com-
mercial and industrial refrigera-
tion equipment 750
3581 Automatic merchandising
machines 250
3562 Ball and roller bearings 750
3564 Blowers and exhaust and ventila-
tion fans 250
3574 Calculating and accounting
machines, except electronic
computing equipment 1,000
3592 Carburetors, pistons, piston rings,
and valves 250
3582 Commercial laundry, dry cleaning,
and pressing machines 250
3531 Construction machinery and
equipment 750
3535 Conveyors and conveying equip-
ment 250
3573 Electronic computing equipment 1,000
3534 Elevators and moving stairways 500
3523 Farm machinery and equipment 500
3551 Food products machinery 250
3524 Garden tractors and lawn and
garden equipment 500
3569 General industrial machinery and
equipment, n.e.c. 250
3536 Hoists, industrial cranes, and
monorail systems 500
3565 Industrial patterns 250
3567 Industrial process furnaces and
ovens 250
3537 Industrial trucks, tractors, trailers
and stackers 750
3545 Machine tool accessories and
measuring devices 250
35452 Precision measuring tools 500
3541 Machine tools, metal cutting types 500
3542 Machine tools, metal forming
types 500
3599 Machinery, except electrical, n.e.c. 250
3586 Measuring and dispensing pumps 500
3568 Mechanical power transaction
equipment, n.e.c. 500
3549 Metalworking machinery, n.e.c. 500
3532 Mining machinery and equip-
ment except oil field machinery
and equipment 500
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Census
Classification
Code Industry or Class of Products
3579 Office machines, n.e.c.
3533 Oil field machinery and equipment
3SS4 Paper industries machinery
3546 Power driven handtools
3555 Printing trades machinery and
equipment
3561 Pumps and pumping equipment
3547 Roofing mill machinery and
equipment
3576 Scales and balances, except
laboratory
3589 Service industry machines, n.e.c.
3544 Special dies and tools, die sets,
jigs and fixtures, and industrial
molds
3559 Special industry machinery, n.e.c.
3556 Speed changers, industrial high
speed drives, and gears
3511 Steam, gas and hydraulic turbines
and turbine generator set units
3552 Textile machinery
3572 Typewriters
3553 Woodworking machinery
Employment
Size Standard
(number of
employees)
500
500
250
500
500
500
500
250
250
Census
Classification
Code Industry or Class of Products
Employment
Size Standard
(number of
employees)
250
250
500
1,000
250
1,000
250
Major Croup 36: Electrical and Electronic Machinery, Equipment
and Supplies
3624 Carbon and graphite products 750
3672 Cathode ray television picture
tubes 750
3646 Commercial, industrial, and insti-
tutional electric lighting fixtures 250
3678 Connectors for electronic appli-
cations 500
3643 Current-carrying wiring devices 500
3634 Electric housewares and fans 750
3641 Electric Lamps 1,000
3694 Electrical equipment for internal
combustion engines 750
3629 Electrical industrial apparatus,
n.e.c. 500
3699 Electrical machinery, equipment
and supplies, n.e.c. 500
3675 Electronic capacitors 500
3677 Electronic coils, transformers,
and other inductors 500
3679 Electronic components, n.e.c. 500
3639 Household appliances, n.e.c. 500
3631 Household cooking equipment 750
3633 Household laundry equipment 1,000
3632 Household refrigerators and
home and farm freezers 1,000
3635 Household vacuum cleaners 750
3622 Industrial Controls 750
3648 Lighting equipment, n.e.c. 250
3621 Motors and generators 1.000
3644 Non-current-carrying wiring
devices 500
3652 Phonograph records and
prerecorded magnetic tape 750
3642 Power, distribution and specialty
transformers 750
3692 Primary batteries, dry and wet 1,000
3651 Radio and television receiving
type electron tubes, except
cathode ray 1.000
3662 Radio and television transmitting
signaling, and detection equip-
ment and apparatus 750
3693 Radiographic X-ray fluoroscopic
X-ray, therapeutic X-ray, and
other X-ray apparatus and tubes;
electro-medical and electro-
therapeutic apparatus
3645 Residential electric lighting
fixtures 250
3676 Resistors, for electronic appli-
cations 500
3674 Semiconductors and related
devices 500
3636 Sewing machines 750
3691 Storage batteries 500
3613 Switchgear and switchboard
apparatus 750
3661 Telephone and telegraph
apparatus 1.000
3673 Transmitting, industrial, and
special purpose electron tubes 750
3647 Vehicular lighting equipment 250
3623 Welding apparatus, electric 250
Major Group 37: Transportation Equipment:
3721 Aircraft 1,500
3724 Aircraft engines and engine parts 1,000
3728 Aircraft parts and auxiliary
equipment, n.e.c. 1,000
3732 Boat building and repairing 250
3761 Guided missiles and space vehicles 250
3769 Guided missile and space
vehicle parts and auxiliary equip-
ment, n.e.c. 1,000
3764 Guided missile and space vehicle
propulsion units and propulsion
unit parts 1,000
3711 Motor vehicle and passenger car
bodies 1,000
3714 Motor vehicle parts and
accessories 500
3751 Motorcycles, bicycles and pans 500
3743 Railroad equipment 750
3731 Ship building and repairing 1,000
3795 Tanks and tank components 1,000
3799 Transportation equipment, n.e.c. 250
3792 Travel trailers and campers 250
3713 Truck and bus bodies 250
3715 Truck trailers 500
79
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Major Group 38: Measuring, Analyzing and Controlling Instruments
Photographic, Metal and Optical Goods; Watches
and Clocks:
3822 Automatic controls for regulating
residential and commercial
environments and appliances SOO
3843 Dental equipment and supplies 250
3811 Engineering, laboratory, scientific
and research instruments and
associated equipment SOO
3823 Industrial instruments for measure-
ment, display and control of
process variables; and related
products 500
3825 Instruments for measuring and
testing of electricity and electrical
signals 500
3829 Measuring and controlling devices,
n.e.c. 500
3851 Opthalmic goods 250
3832 Optical instruments and lenses 250
3842 Orthopedic, prosthetic, and surgi-
cal appliances and supplies 250
3861 Photographic equipment and
supplies 500
3841 Surgical and medical instruments
and apparatus 250
3824 Totalizing fluid meters and count-
ing devices 500
3873 Watches, clocks, clockwork
operated devices, and parts 500
Major Group 39: Miscellaneous Manufacturing Industries:
3991 Brooms and brushes 250
3963 Buttons 250
3995 Burial Caskets 250
3955 Carbon paper and inked ribbon 250
3961 Costume jewelry and costume
novelties, except precious metals 250
3942 Dolls 250
3962 Feathers, plumes, and artificial
trees and flowers 250
3944 Games, toys and children's vehicles
except dolls and bicycles 250
3915 Jeweler's findings and materials
and lapidiary work 250
3911 Jewelry, precious metal 250
3952 Lead pencils, crayons, and artists'
materials 250
3996 Linoleum, asphalted felt base,
and other hard surface floor
coverings, n.e.c. 750
3999 Manufacturing industries, n.e.c. 250
39993 Matches 500
3963 Marking devices 250
3931 Musical instruments 250
3964 Needles, pins, hooks, and eyes,
and similar notions 250
3951 Pens, mechanical pencils, and pans 500
3993 Signs and advertising displays 250
3914 Silverware, plated ware, and
stainless steelware 500
3949 Sporting athletic goods, n.e.c. 250
SB A Requirements
A regulated firm is eligible to apply for a Federal Water
Pollution Control loan only if it meets certain
requirements of the Small Business Administration and
the Environmental Protection Agency.
The Small Business Administration considers a
business to be eligible for a pollution control loan
application if:
• the firm meets small business size standards,
• the business is not new
• the firm meets certain industry classification
requirements
• the business demonstrates that regulatory
requirements will cause the firm serious economic
injury
• the business has received certification from the
Environmental Protection Agency that the
proposed pollution abatement measure(s) are
necessary and adequate to comply with regulatory
requirements imposed on the firm.
TO APPLY FOR A LOAN -
STEP-BY-STEP PROCEDURE
1. Prepare a current financial statement (balance
sheet) listing all assets and all liabilities of the business -
do not include personal items.
2. Have an earning (profit and loss) statement for the
previous full year and for the current period to the date of
the balance sheet.
3. Prepare a current personal financial statement of
the owner, or each partner or stockholder owning 20
percent or more of the corporate stock in business.
4. List collateral to be offered as security for the loan,
with your estimate of the present market value of each
item.
5. State amount of loan requested and explain exact
purposes for which it will be used.
6. See your banker. Ask for a direct loan and if
declined, ask the bank to make loan under SBA's loan
guaranty plan or to participate with SBA in a loan. If the
bank is interested in an SBA guaranty or participation
loan, ask the banker to contact SBA for discussion of
your application.
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7. Visit SBA office for direct loan for economic injury
loan for water pollution control, apply after you received
EPA or other official notification and have consulted
with your engineer and devised an abatement plan.
In addition to the SBA loan program their are various
other government agencies that have programs which
may be beneficial to businesses seeking help for their
pollution control abatement needs.
The Economic Development Administration has
direct loans or loan guarantees with interest rates below
market. The Farmers Home Administration also has
various loan and grant programs.
SBA Guaranteed Pollution Control Revenue Bonds
Public Law 94-305 authorized SBA to guarantee the
payments under qualified contracts entered into by
existing small business concerns which are, or are likely
to be, at an operational or financing disadvantage with
other businesses for the purpose of acquiring pollution
control facilities. The statute specifically provides that
financing of the pollution control facilities can be
obtained through the use of industrial revenue bonds
issued by a state or municipality.
The purpose of using tax exempt industrial revenue
bond financing for pollution control facilities is to obtain
the most advantageous interest rate and repayment terms
possible.
Revenue bond financing is, and has been, extensively
utilized by large businesses for their financing of
pollution control facilities. Large businesses which are
dominant in their industry, are generally recognized
nationally and/or internationally and they usually have a
very wide market available, including the bond market,
for their financing needs. Small businesses on the other
hand, because they are primarily local or regional
operations and account for only a very small percentage
of their industry's output, do not generally have wide
sources of financing available. The Department of
Treasury estimates that in 1978, 3.1 billion worth of
industrial bonds for pollution control were issued and by
1979 the figure is expected to rise to 3.3 billion. To
implement Public Law 94-305, SBA is cooperating with
commercial banks, state authorities, and bond
underwriters to make long-term, low interest financing
available to well established larger small businesses
through tax-exempt revenue bonds. This is essentially the
same way large corporations obtain financing for their
pollution facilities.
1. Public entity issues tax exempt revenue bonds on
which repayment is based solely on the credit of the
business.
2. Public entity is the nominal owner of the property.
3. Property is conveyed to the business under a lease,
lease-purchase installment sale, etc.
4. The business may obtain additional tax advantages
such as the investment tax credit and accelerated
depreciation.
The need for the program is to put a smaller firm on an
equal footing with the giant firms. The program may also
allow smaller firms to combine into one package their
requirement and issue the bonds collectively.
To qualify for this program a small business must be
one which together with its affiliates is independently
owned and operated, is not dominant in its field of
operation and has less than nine million dollars in annual
revenues.
The company must have a net worth less than 4 million
dollars and an average net income over the past two years
less than $400,000.
The company had to be in existence at least 5 years of
which 3 out of the last 5 years were profitable. The most
important criteria, however, is that the company has
sufficient cash flow to pay off the debt over a twenty year
period.
The applicant must provide evidence of the need for
the pollution control facility (from State or Federal
Agency).
The company may qualify as a small business concern
under 121.3-10 (no. of employees of specific industry
group.)
Applicants for guaranteed financing through the
authority should have qualified sponsors (their bank or
other financial organization). The sponsor must provide
the authority and SBA with a certificate that applicant is
creditworthy, and is at a financing or operational
disadvantage in the long term, tax exempt credit makers.
To be eligible the project must be new, and the
application must be processed and accepted before
construction begins.
The repayment period for the pollution control
financing is 25 years and will generally be tied to the
expected useful life of the facility.
The required financing should not exceed 4 million
dollars. Generally included are all costs connected with
construction and/or installation of the facility.
What is the process?
A small business initially requests a loan from a state or
local authority empowered to issue the bonds.
In most states it is the state economic development
agency or business development agency. In other areas,
bonds are issued directly by municipalities.
The authority in turn requests that the SBA guarantee
the loan. The SBA, after reviewing the applicants'
business qualifications under program guidelines, agrees
to guarantee the loan and reports to the authority. When
the authority has several businesses with SBA approval it
can package a bond issue of marketable size. The issue is
marketed through an underwriter and the proceeds from
the issue are made to the businesses.
The loan funds are deposited with an appointed
trustee. The businessman can use the proceeds, over a
three year period, to finance construction and equipment
required to meet environmental control standards, costs
of site preparation, and all expenses necessary to begin
and supervise construction, including legal and
engineering costs. These funds may also be used to pay
bond issuance expenses, application fees, establish a
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reserve fund and refinance existing debt for a pollution
control facility. They may not be used to replenish
working capital. Funds are dispersed by the trustee upon
receipt of invoices for any of the approved uses.
How available is the financing?
The market for SBA guaranteed Industrial Pollution
Control Bonds is strong. California, Illinois, and
Alabama have already issued bonds. Six or eight other
states have the machinery in place, and by the end of this
year at least half the states will be prepared to provide
such financing.
It is up to the businessman to seek out the issuing
authority in his state.
For further information on any of the financial
assistance programs call me at (202-755-3624) or write to
me at 401 M St. S. W., mail code WH-586, Washington,
D. C. 20460
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SUMMARY OF EVENING SESSION
Purpose of Evening Session
To concentrate on frank interchanges between
attendees, consultants and EPA officials on the
metal finishing industry's needs and problems in
pollution control technology.
Evening Session Panel Members:
Moderator: Kenneth Coulter, AES Environmental
Committee
Panelists: Dr. E. E. Berkau, Dir., EPA Industrial
Pollution Control Division, Industrial Environ-
mental Research Lab.
Robert B. Schaffer, Dir., EPA Effluent
Guidelines Div., Washington, DC
Nancy J. Hutzel, Program Analyst, EPA
Permits Div., Office of Water Enforcement,
Washington, DC
Gary McKee, Supervisory Chemist, EPA
Environmental Monitoring & Support Lab.,
Cincinnati, OH
John Dickenson, Coordinator, Solid Waste
Section, Region IV, EPA, Atlanta, GA
Simon P. Gary, AES First Vice President,
Scientific Control Labs., Inc.
Richard W. Grain, AES Environmental
Committee, Industrial Filter and Pump Mfg. Co.
Dr. Clarency Roy, AES Environmental
Committee, Aqualogic Inc.
Bud Weber, Genessee Valley Metal
Finishing Co., Inc.
SUMMARY OF DISCUSSION POINTS
RAISED DURING EVENING SESSION
The vast majority of the comments and questions
raised during the evening session dealt with the
regulations affecting the electroplating industry,
the need to communicate these regulations to the
users, and the need for RD&D in sludge
characterization and centralized treatment.
Specifically:
• There were many questions to Robert Schaffer
relating to which regulations affected the
electroplating industry and when they became
effective. Nancy Hutzel was asked how the
pretreatment requirements affected the electro-
plating industry, especially the requirements of
40CFR303. This section requires reporting
within 180 days after the publication of the
general pretreatment regulations on the status of
meeting pretreatment regulations. It was obvious
from the comments that most of theelectroplaters
present were not aware of the reporting require-
ment, and those who were aware were not sure
of the status of the proposed regulations for elec-
troplating. Mr. Schaffer stated that he would
check with EPA's Office of General Council to
determine the status of the regulations.
There was a question as to which has priority -
state and local regulations, orfederal regulations.
The answer was that nothing precludes a state or
local agency from setting any regulation that they
wish, but that the federal overrides state and local
regulations if the federal regulation is more
stringent.
One conference attendee pointed out that the
preamble to the Resource Conservation and
Recovery Regulations mentions that inadequate
data are available to set regulations. He asked
what EPA was doing in this regard. Dr. Eugene
Berkau reported that the EPA/AES grant on
sludge characterization had been awarded and
work to provide data would be underway shortly.
Several electroplaters expressed that the
cadmium problem could be solved if military
specifications did not require the use of cadmium
in electroplating. Simon Gary expressed a belief
that cadmium was advantageous for some uses.
A great deal of support for the centralized
treatment research was evidenced. Timing of this
project was also emphasized in that
electroplaters need answers soon if the option is
to be viable. Dr. Berkau explained that the phased
approach of screening regions first, rather than
going ahead with the demonstration, is necessary
because it is important that the demonstration be
successful and representative of a wide range of
situations in the United States.
A potential problem with the pretreatment
regulation was highlighted by questions as to
how changing POTW removal allowances are
handled. Electroplating representatives
explained that if a system were designed for a
large removal allowance, a change in that removal
allowance could result in redesign of the system.
83
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• There were a number of questions on the legal
ramifications of sludge handling and disposal. A
great deal of concern on the electroplater's part
was evident as to possible long-term liabilities
from the waste material generated. It was
explained that this issue would be dealt with on a
case-by-case basis by local courts.
• There was a question as to when a source
becomes a new source. Mr. Schaffer explained
that if construction is initiated after proposal and
the regulation is promulgated within 120 days
after proposal, it is a new source. In the case of
electroplaters, there will not be any new sources
until the regulation is promulgated, because it has
been more than 120 days since proposal.
• A question was raised as to how a person
petitions to get a pollutant removed from the
priority pollutant list. Mr. Schaffer explained that
the proper procedure was to send a letter to the
Effluent Guidelines Division requesting such a
deletion. He mentioned that several of such
requests have been received.
A representative of one of the trade magazines,
along with many electroplaters in the audience,
expressed the need for better communication of
regulations from EPA to the affected industries.
They explained that most electroplaters do not
read the Federal Register and when they do, they
have difficulty understanding the legal language.
Concerns were expressed as to the need for the
Office of Solid Waste and the Effluent Guidelines
Division to work more closely together.
There were only a few technical questions.
Clarence Roy discussed types of treatment for
copper and nickel complexes and the technology
and shortcomings of breakpoint chlorination.
84
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Water Recycling and Nickel Recovery
Using Ion Exchange
Kenneth Price (Oldsmobile) & Charles Novotny (Industrial)*
In 1972 Oldsmobile installed two ion exchange systems
supplied by Industrial Filter & Pump Mfg. Co. The
exchange systems were designed to treat nickel rinse
water from the bumper plating lines at Plants #1 and #3.
The treatment systems were designed to accomplish
three purposes: (1) Reduction of nickel metal in the plant
effluent discharged to the City of Lansing, (2) Recovery
of nickel metal, (3) Recovery of the rinse water itself.
General Process Description
The nickel rinse water from the spray rinse following
the final nickel plating step is collected in a sump and
pumped to a 10,000 gallon filter supply tank. The transfer
pumps operate automatically and are controlled by level
controls in the sump tank.
From the filter supply tank, the water is pumped
through a filter to remove Dur-Ni solids present in the
final plating step before rinsing. A coagulant is added to
aid in the filtration.
The filtrate then passes through one of two, three-bed
ion exchange trains. The first column is a cation
exchanger using Dowex HCR-W strong acid resin. This
column removes the nickel and other cations present in
the water. The water continues on through a weak base
exchanger containing Dow WGR resin and a strong base
exchanger containing Dow SBR resin.
This combination of weak base exchange followed by
strong base exchange takes advantage of the high
capacity and efficiency of weak base resin regeneration to
remove most of the anions and the ability of the strong
base resin to remove silicates and borates for a final
"polish."
The solution emerging from the strong base exchanger
is high quality demineralized water. This is stored in a
5000 gallon D. I. water tank and recycled back into the
plating process as the nickel spray rinse. Make-up water
is added to the storage tank as required. This water is also
deionized.
When one train becomes exhausted, the other train is
'Kenneth Price
Oldsmobile Div.. GMC, Lancing, Ml
Charles J. Novotny
Industrial Filter & Pump Mfg. Co.. Cicero, IL
put on stream and the exhausted train is regenerated. The
cation column is regenerated with sulfuric acid. A
quadruple reuse of acid is employed to reduce the amount
of excess acidity in the spent regenerant.
The anion exchangers are regenerated in series. Fresh
sodium hydroxide solution is pumped into the strong
base exchanger and then into the weak base exchanger.
There is enough free sodium hydroxide left after passing
through the strong base column to regenerate the weak
base column.
The recovered nickel sulfate solution, at about 5.0-5.5
oz/gallon nickel metal, is further concentrated to 10.0 -
11.0 oz, gallon nickel metal using an atmospheric
evaporator. The concentrated solution is sold for
reprocessing.
During periods of downtime on the plating process -
weekends, breakdown, etc. - a level control in the filter
supply tank diverts the water from the strong base
exchanger back to the filter supply tank. This permits a
constant "head" on the filter and prevents potential
"souring" of water that would stay in the exchange
columns if flow were stopped.
Process Specifications
An ion exchange train is considered exhausted when
the water emerging from the strong base exchanger has a
resistance of 20,000 ohms @ 60° F. A freshly regenerated
train is considered ready for service at the same point.
The resin volumes for the exchange columns are: Plant
#3: Cation 100 ft. \ weak base 135 ft.-1, and strong base 50
ft.1. At Plant #1: Cation 65 ft.1, weak base 85 ft.1, and
strong base 30 ft.3. The size differences between plants are
due to the fact that the plating capacity at Plant ft 1 is less
than Plant #3. The rinse rate is also lower at Plant #1.
The cycle time for one three-bed system is
approximately 60 hours at each plant. Since each cubic
foot of cation resin has an estimated capacity of 2.0 - 2.4
pounds of nickel, each cycle removes 200 - 240 pounds of
nickel at Plant #3 and 130 - 155 pounds of nickel at Plant
#1.
The cation resin at Plant #3 is regenerated with 500
gallons of 20% sulfuric acid (950 pounds).
The anions resins are regenerated with 510 gallons of
10% caustic, (950 pounds of 50% NaOH).
Correspondingly, for Plant #1, the cation resin
requires 350 gallons of 20% sulfuric acid (665 pounds);
the anion resins use 300 gallons of 10% caustic (550
85
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pounds of 5()cc NaOH). The table below summarizes
these data:
Plum tf3
Plain HI
Rinse Mow
C'iilion Resin
Weak Hase Resin
Strong Base Rcsm
Cation Rcgeneranl
\nion Regcncram
Cvcle I ime
Ni cone, in t-eed
100 gpm 60 gpm
100 ft.1 65 ft.'
DOW-HCR-W DOW-HCR-W
135 It.1 OOW-W(iR85 It.1 DOW-W(iR
M) It.1 DOW-SBR .10 ft ' DOW-SBR
950 Ibs. H:S(X 665 Ibs. H-SOa
950 Ibs. 50'V NaOH 550 Ibs. 50r; NaOH
60 hours 60 hours
40 - 60 IM'M 40 - 60 IM'M
Regeneration
Regeneration of a train is initiated by the attendant
simply by energizing the first step in an automatically
sequenced series of regeneration steps. The indexing
from one step to another is then controlled by a timer or
level control. Each step may be controlled by a manual
advance cycle button if an extended time on a given step
is desired.
The quadruple use of acid is accomplished by using a
series of five tanks. The last tank is the final used acid and
the first is the fresh acid.
During regeneration, the thrice used acid is pumped
into the exchanger and displaced by twice used ucid; the
twice used acid is displaced by once used acid; the once
used acid by fresh acid; and the fresh acid by water. Thus
the solution is displaced down the line of tanks until the
final concentrated solution is obtained.
The caustic regenerant is pumped into the strong base
exchanger and on into the weak base exchanger. The
regenerant is then displaced from the strong base through
the weak base with decationized water and the columns
reused in series.
Finally the entire three-bed train is rinsed - usually an
hour to one and one half hours - until a water quality of
20.000 ohms is reached.
Problems
The original intent of the recovery system was to
recycle the water and reuse the nickel sulfate solution
back in the plating tanks.
In order to do this, a number of conditions needed to
be met:
I. The pH of the solution to be 3.0 - 3.5,2. Only minute
quantities of contaminating metals could be present, 3. A
low level of sodium ion - 2000 ppm or below - had to be
achieved.
To adjust the final used acid to an acceptable level, the
process was to employ a single weak base exchange
column containing DOW-WGR resin.
The solution from the cation regeneration was to be
pumped through this column where the excess acidity
was to be removed. The weak anion resin was expected to
be capable of removing this excess acid without splitting
the neutral nickel sulfate salts.
This was never achieved. The metal precipitated in the
column causing fouling. Partial regeneration to reduce
column capacity was attempted but no improvement was
noted. The problem appeared to be due to the fact that
although the volume of resin available has the capability
of removing the excess acidity from a batch of solution,
only a small amount of solution contacts the resin at a
given time. The pH of the environment precipitates the
nickel that eventually plugs the column and prevents the
continued flow of acid solution. The precipitated metal
can not be redissolved by incoming low pH solution.
Efforts to utilize ion exchange to adjust the pH of the
solution were abandoned and nickel carbonate was used
to achieve the desired pH.
A low level of sodium ion was required because the
solution was to be added to the semi-bright nickel plating
tank. Dragout from one plating tank into the other meant
that the first nickel plating step needed the vast majority
of nickel salt additions. Sodium ion is known to have a
limiting effect on current in semi-bright nickel.
Since the amount of sodium ion in Dur-Ni plating bath
is higher in proportion to the nickel metal than is
acceptable in semi-bright, immediate regeneration of a
cation column after exhaustion would have resulted in
excess sodium levels in the recovered solution.
To remove unwanted sodium ion from the cation
column, a deplacement step was used.
Displacement takes advantage of the fact that
although a cation resin will remove all cations from a
solution, it will hang on to some much more tightly than
others.
When a column becomes exhausted, nearly all the sites
on the column are occupied by a cation. If a mixture of
cations in solution is allowed to pass through this
exhausted column the resin will continue to exchange.
The resin will exchange a weakly held cation for a more
strongly held cation.
In this case, when nickel rinse water is passed through
an exhausted column, the column will exchange a nickel
ion in the solution for a sodium ion on the resin. Thus the
sodium ion is displaced from the resin into the solution.
The sodium laden rinse water is permitted to pass from
the cation column into the plant effluent.
The displacement is allowed to continue until enough
sodium has been displaced that the regenerant solution is
low enough to be used in the plating bath.
The time required to displace sodium was expected to
be 30 min. During this period, the nickel rinse water
flowed into the cation column and into the plant effluent.
Thus, no water was recycled while sodium was being
displaced.
It was found that 30 min. did not allow sufficient time
to displace sodium. In order to achieve acceptable levels
of sodium ion a four to six hour displacement period was
required.
This long period of displacement depleated the supply
of D.I. water. The original process used soft water at
Plant #3 and city water at Plant #1 as make-up. The
addition of large amounts of city water at Plant #1
elevated calcium levels in the recovered solution.
Calcium salts precipitated in the plating tank on the air
86
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agitation system and eventually forced us to discontinue
the reuse of the solution in the plating tanks.
At Plant #3 the soft water make-up added enough
sodium ion that the displacement step did not reduce
sodium levels enough to allow use of the solution.
The long displacement time was due to two factors:
One was that changes in the configuration of the
bumpers reduced the nickel concentration in the
incoming rinse water by 50 - 60 percent. This meant less
metal was available to displace the sodium and
displacement time was increased.
The second reason was that the use of city and soft
water as make-up introduced additional sodium into the
system which also lengthened displacement time.
Oldsmobile felt that D. 1. water make-up was not
necessary even though it was recommended by the
equipment manufacturer.
It is now felt ihat if deionized (or at least decationized)
water were used for make-up, the recovered nickel would
be reuseable directly into the plating tanks. First, there
would be few cations present other than nickel and the
displacement of sodium step would be much shorter.
Next, the recovery ion exchange system cycles would
be lengthened by the reduced load. Overall operating
expensed would not be increased by addition of make-up
water demineralizers since the mineral content of the
make up is now being removed by the recovery system. In
fact, overall economics would be improved.
Summary
Although the ion exchange processes at Oldsmobile
did not fully achieve all the objectives hoped for, it still
recycles a combined 50 million gallons of water and
recovers about 30,000 Ibs. of nickel metal annually.
In addition, significant reductions of nickel metal in
plant effluent has been observed.
Oldsmobile is also able to rinse following a Dur-Ni
plating step with only one rinse tank. In many cases,
several rinse steps are used reclaim, cold water, hot
water - to conserve water and reduce nickel dragout.
Using one tank instead of two or three is accomplished
because a high volume of water may be employed without
wasting water. The metal, in very small concentration,
can also be recovered.
This can be an advantage if space requirements are a
consideration when a new installation or modification of
old equipment is contemplated.
Resin attrition rates indicate that a constant
replacement of resin at high expense is not a factor for
consideration in this type of ion exchange application.
Periodic checks of the resins show the following losses
in total resin capacity per year.
Cation Resin
Weak Base Resin
Strong Base Resin
2% - 3%
Under 1%
3% - 4%
Normal cleaning of resins is limited to an occasional
(once or twice per year) soaking of the resins with warm
(140° F.) inhibited hydrochloric acid.
Most waste treatment processes will not be self-
supporting. The ion exchange process described is not
self supporting since not all of the operating costs are
recovered. However, recycling does eliminate much of
the cost associated with methods that generate a solid
waste that must be disposed.
Recovery and recycling using ion exchange has wide
application in the electroplating industry. Its use should
be given careful consideration when waste treatment
systems are being designed.
87
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Field Demonstration of Closed-Loop Recovery
Of Zinc Cyanide Rinsewater
Using Reverse Osmosis and Evaporation
Kenneth J. McNulty & John W. Kubarewicz*
ABSTRACT
A field test was conducted to demonstrate closed-loop recovery of zinc cyanide rinsewater
at a job shop plat ing facility. Since the zinc cyanide bath operates at room temperature with very
little evaporation from the bath, reverse osmosis (RO) treatment of the rinsewater must be
supplemented by evaporation in order to achieve the volume reduction necessary for return of a
concentrate to the plating bath. The permeate from the RO unit was recycled to the first rinse
after plating while the distillate from the evaporator was recycled to the second rinse after
plating. Continuous, unattended operation of this system was demonstrated with no adverse
effects on plating quality.
Spiral-wound PA-300 membrane modules were used in the RO unit. Periodic tests were
conducted throughout the demonstration to characterize membrane performance under
standard conditions. These tests indicated a gradual loss in membrane flux and rejection. After
3,000 hours of exposure to the rinsewater, the membranes were cleaned by flushing with a
cleaning solution. The cleaning resulted in nearly complete restoration afflux and rejection.
The gradual loss in membrane performance is thus attributable to fouling of the membrane by
particulates in the rinsewater. Such fouling can be reduced by better pre-filtration and reversed
by periodic cleaning.
The economics of the combined RO evaporation system were assessed for a system
designed to provide rinsing equivalent to the present two-stage counter-current rinse at the
demonstration site. The analysis showed that the total operating cost (including amortization)
was somewhat less for the combined RO evaporation system than for evaporation alone. The
minimum cost occurred for 90% water recovery in the RO system. However credits for
rinsewater recovery were insufficient to completely off-set the total operating cost of the
recovery system.
INTRODUCTION
Wastewater treatment technologies for the
electroplating industry can be broadly classified as end-
of-pipe destruction processes or in-plant recovery
processes. The end-of-pipe destruction processes treat a
total shop effluent to remove a mixture of heavy metals.
At present it is neither technically nor economically
feasible to recover and recycle metals from the end-of-
pipe processes (1). On the other hand, in-plant recovery
processes treat rinsewater from a specific plating bath (or
other operation) making it possible to recover and return
the heavy metals to the plating bath.
Because of the inherent disadvantage of end-of-pipe
'Kenneth J. McNulty & John W. Kubarewicz
Walden Division of Abcor, Inc.
850 Main Street. Wilmington. MA 01887
treatment—loss of valuable plating chemicals, cost of
treatment chemicals, cost of sludge disposal—increasing
attention has been focused on closed-loop recovery
methods. In many cases, the economics of closed-loop
recovery have been very favorable resulting in rapid
payback on the capital investment for recovery
equipment (2).
Aside from a few applications in which closed-loop
recovery can be achieved by counter-current rinsing
alone, some technique must be used to remove the
dissolved plating chemicals from the rinsewater.
Although other techniques are under development,
evaporation, reverse osmosis (RO), and ion exchange are
the most commonly used processes for rinsewater
recovery (1,3). Each of these techniques has particular
advantages and disadvantages, and the best technique or
combination of techniques will depend on factors specific
to each application.
88
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A number of advantages can be cited for the use of RO
in rinsewater recovery. These include low capital cost,
low energy and operating costs, and minimal space
requirements. However, there are also some limitations.
The two major limitations for RO are:
I. The membrane modules deteriorate with time and
require periodic replacement. The rate of
deterioration depends on the type of membrane, the
rinsewater pH and temperature, and the
concentration of other reactants in the rinsewater
such as oxidants.
2. Reverse osmosis cannot produce a highly
concentrated stream for recycle to the plating bath.
Thus for ambient temperature baths, RO must be
supplemented with some other concentration
technique, such as evaporation, in order to close the
loop.
To date, RO has been applied primarily to the recovery
of nickel rinsewaters. For nickel, the rinsewaters are
relatively mild in pH (4-6) resulting in acceptable life for
the conventional commercial membranes (cellulose
acetate and aromatic polyamide). In addition, nickel
baths operate at elevated temperatures where substantial
evaporation occurs, and closed-loop operation can be
achieved with RO alone.
Several programs, jointly sponsored by EPA and AES,
have been conducted to evaluate the applicability of RO
to plating baths other than nickel (4, 5, 6). Laboratory
tests were conducted with a variety of newly developed
membranes and rinsewaters with extreme pH levels (6).
These tests indicated that of the membranes tested, the
PA-300 was superior to the other membranes for
treatment of copper cyanide, zinc cyanide, and chromic
acid rinsewaters. The PA-300 membrane has since been
commercialized (currently designated TFC-PA;
manufactured by Fluid Systems Division of UOP) and is
available in a spiral-wound modular configuration.
A field test was undertaken to evaluate the PA-300
membrane module for recovery of zinc cyanide
rinsewater under realistic conditions. Zinc cyanide was
selected because of the large volume of zinc cyanide
plating done by the industry and because the high pH of
the rinsewaters would provide a "worst case" test of the
membrane for resistance to alkaline conditions. Since the
zinc cyanide bath operates at room temperature, it was
necessary to use an evaporator to supplement RO
treatment and achieve the level of concentration
necessary for closed-loop operation. This paper presents
and discusses the results of this field test.
METHODS AND MATERIALS
A mobile RO test system was leased from Abcor, Inc.
and an evaporator was leased from Wastesaver
Corporation for the duration of the field test. These two
units were installed on an automatic rack, zinc cyanide
plating line at New England Plating Co. in Worcester,
Massachusetts. The overall schematic of the installation
is shown in Figure 1. Feed to the RO system was
withdrawn from Rinse Tank No. I and separated by the
DISTILLATE
DISTILLATE
(0.22 gpm)
VAPORATOR
ONCENTRATE
(1.0 gpm)
Fig. 1—Overall Schematic of RO/Evaporator Operation.
RO system into a permeate stream and a concentrate
stream. For purposes of design, it was assumed that the
RO system would produce about 2 gpm of permeate and
would operate at 90% conversion. (Conversion is defined
as the ratio of permeate flow to feed flow.) Thus the RO
system would be fed at the rate of 2.22 gpm and would
produce concentrate at the rate of 0.22 gpm. The
permeate was returned to Rinse Tank No. I and the
concentrate was fed to the evaporator.
Since dragin and dragout were essentially identical for
the plating bath and the rate of evaporation was
negligible, there was no room in the plating bath for a
concentrate stream. If the evaporator were fed only RO
concentrate, it would have to evaporate it to dryness in
order to prevent eventual overflow of the bath. In order
to prevent precipitation of plating chemicals in the
evaporator a I gpm purge stream was circulated from the
plating bath through the evaporator and carried the
plating salts introduced with the RO concentrate back to
the plating bath. That is, the evaporator concentrate was
higher in concentration than the plating bath by the
amount added by the RO concentrate. The distillate from
the evaporator was collected in a holding tank and added
at a controlled rate to Rinse Tank No. 2. A float valve
operating off the level in Rinse Tank No. I insured that
the rate of RO concentrate production was exactly
balanced by the rate of distillate returned to Rinse Tank
No. 2. A slight excess of distillate was produced to insure
that the holding tank would always remain full; and the
excess was permitted to overflow into the plating bath
(0.02 gpm). The steam rate was cut back to minimize
overflow from the holding tank.
89
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n
i
r1
j©
/^! T „ . oiuiiuu u
•1 ^^! Q" • M HUH
Fig. 2—Flow Schematic tor RO Demonstration Syitem.
Fig. 3—Flow Schematic lor Evaporator.
A flow schematic of the RO system is shown in Figure
2. Feed from the first rinse tank was withdrawn by a
booster pump and passed through two cartridge filters in
parallel. Both l-n and 20-/i filters were used at different
times during the field test. Excess flow from the booster
pump was returned to the rinse tank. After pre-filtration,
the feed was pressurized to 700 psi with multi-stage
centrifugal feed pump and passed through three 4-inch
diameter, spiral-wound, PA-300 modules arranged in
series. Most of the concentrate from the third module was
recycled to the suction of the feed pump in order to
maintain the required feed flow rate through the
modules. A heat exchanger in the recirculation loop
removed heat generated by the energy input of the
pumps. A small flow of concentrate from the third
module was fed to the evaporator (see Figure 1), and the
permeate from the three modules was combined and
returned to the first rinse tank. The instrumentation and
controls for the RO system are shown in Figure 2.
In order to characterize membrane performance with a
standard feed solution, the RO system was periodically
operated in a total recycle mode using the auxiliary feed
tank. For this mode of operation, the booster pump
recycle line was closed off, the concentrate line to the
evaporator was opened, and the permeate was returned
to the auxiliary tank rather than the rinse tank. The
standard solution (generally a portion of plating bath
diluted to 10% by volume of original bath strength) was
charged to the auxiliary tank and the system was
operated with total recycle until steady state was
achieved. At steady state, the permeate flow rate for each
module was measured, and samples of the feed and
permeate from each module were obtained for analysis.
Typical operating conditions for both closed-loop and
total recycle were:
Feed Pressure
Recirculation Flow Rate
Temperature
Concentrate Flow Rate
700 psi
10 gpm
70 - 90° F
0.2 gpm (closed-loop only)
The flow schematic for the evaporator is shown in
Figure 3. Steam was fed through a pressure reducing
valve to a tube bundle submerged in the boiler section of
the evaporator, and steam condensate was returned to
the plant boiler. For most installations, a cooling tower is
used to cool the water which is recirculated through the
condenser section of the evaporator. However, for this
installation it was more convenient to use recirculated
chilled water since it was readily available at the
installation site and the chiller had sufficient excess
capacity. The evaporator was maintained under vacuum
by circulating water through an eductor. Cooling water
was added to the eductor tank to remove the energy input
of the eductor circulation pump. Feed to the evaporator
was controlled by a level switch (LS) and solenoid valve.
Upon low level signal, the solenoid valve opened and feed
was drawn by vacuum into the evaporator. The distillate
from evaporation of the feed condensed, was collected in
a tray below the condenser, and was continuously
pumped back to the second rinse after plating (see Figure
1). The concentrate from the boiler section of the
evaporator was continuously pumped back to the plating
bath.
Typical operating conditions for the evaporator were:
Vacuum
Temperature
Steam Pressure
Concentrate Flow Rate
26 - 27 in. Hg
100- 110° F
<5 psi
I gpm
During the field test, the RO modules were cleaned
using a cleaning sequence recommended by the
membrane manufacturer. The modules were first flushed
with 50 gal of water to remove the plating chemicals. A
0.1% by volume solution of Triton X-100, a non-ionic
surfactant, was prepared and recirculated through the
modules at a pressure of 700 psi, a flow rate of 10 gpm,
and a temperature of 120° F for 45 minutes. After
flushing with another 50 gallons of water, 2% citric acid
solution was prepared and adjusted to pH 3.0 with
ammonium hydroxide. This solution was recirculated
through the modules at the same conditions and for the
same time as the Triton X-100. Following the citric acid
cleaning the system was again flushed with water and
returned to treatment of zinc cyanide rinsewater. Since
the PA-300 membrane is rapidly degraded by chlorine,
all water used for flushing and preparing cleaning
solutions was dechlorinated by the addition of sodium
sulfite.
90
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Samples collected during the field test were analyzed
for zinc (atomic absorption), free cyanide (selective ion
electrode), total solids (gravimetric) (determination of
residue), conductivity (conductivity bridge), and pH
(electrode).
The nominal composition of the plating bath was:
Zn (as metal) 20.000 mg/1 2.7 oz/gal
CN (as NaCN) 60.000 mg/1 8.0 oz/gal
Caustic 75.000 mg/l 10.0 oz/gal
Brightener
(700 Special) 4 ml/I 4 gal/1000 gal
In addition to these compounds, polysulfide was
regularly added to the bath for purification, and the bath
also contained a large quantity of carbonates. The total
solids concentration of the bath was in the vicinity of
350,000 mg/1 (35% by weight).
RESULTS AND DISCUSSION
Field activities covered the months of June through
December of 1978. During this time, the system was
operated primarily in the closed-loop mode shown in
Figure 1. However, closed-loop operation was
periodically interrupted to conduct total recycle tests on
the RO system. The performance of RO modules is
generally assessed in terms of the module flux (rate of
permeate production per unit membrane area) given in
gallons per ft2 per day (gfd) and the rejection (defined for
a particular dissolved species as one minus the ratio of
permeate to feed concentrations) given in percent. Since
both flux and rejection depend on feed concentration, it
is necessary to conduct RO performance tests at a fixed
feed concentration in order to be able to accurately
interpret trends in the flux and rejection data. During
closed-loop operation the feed concentration to the RO
system can vary considerably (depending on the parts
being plated and their d ragout); hence total recycle tests
at a fixed feed concentration (10% of bath strength) were
periodically conducted to accurately assess trends in the
RO system performance. System performance was
monitored less rigorously during operation in the closed-
loop mode.
The total operating time for the field demonstration
(time during which permeate was being produced) was
approximately 1000 hours. The total exposure time of the
modules to the rinsewater, however, was about 4,200
hours. The longer exposure time reflects the system
down-time during which the modules were sitting in
contact with the concentrated zinc cyanide rinsewater.
Various factors contributed to the system down-time,
including: electro-mechanical failure of various system
components, high or low alarm shut-down of the system,
weekends and holidays. The total exposure time is
probably more significant than operating time in
controlling the degree to which the modules are attacked
chemically by constituents in the rinsewater (e.g.,
caustic). On the other hand, operating time is more
significant in controlling the degree to which the modules
become fouled with particulates in the feed. Correlations
presented below are based on exposure time. However,
the operating time was reasonably evenly spread over the
test program, and correlations on an operating-time basis
would be similar.
Closed-Loop Operation
The RO/evaporator system was designed to operate
continuously, with no operator attention, between start-
up Monday morning and shut-down Friday afternoon.
However, during most of the field test program, various
electro-mechanical and other problems occurred which
prevented unattended week-long operation. Each failure
generally resulted in several days down time because of
the logistics of getting project personnel to the field site,
diagnosing the problem, and implementing remedial
action. Eventually these problems were solved and week-
long unattended operation was demonstrated.
During demonstration of the closed-loop system, no
adverse effects were noted on the quality of the plated
parts. However, the rinse tanks after zinc plating were
followed by an acid dip, a flowing rinse, and other surface
finishing steps before the parts were finally inspected.
Therefore the degree of rinsing following zinc cyanide
plating was probably not of critical importance to quality
control.
Both the RO system and evaporator were under-
designed as a direct replacement for the two-stage
countercurrent rinse at a nominal rinsewater flow rate of
2 gpm (see "Economics" below). The system design
reflected limitations imposed on program costs,
availability of PA-300 modules at the time the system was
fabricated, and lack of design data for the zinc cyanide
application. Nevertheless, the system was of sufficient
size to obtain meaningful design and economic data.
RO performance during closed-loop operation was
monitored by measuring the productivity of each module
(rate of permeate production) and by monitoring the
conductivity of the combined RO permeate. In general,
the productivity during closed-loop operation was
similar (but slightly higher) than the productivity during
the total recycle tests (see discussion below). The
conductivity of the combined permeate generally ranged
between 2,000 and 4,500 /i-mhos/cm. This is equivalent
to a total solids concentration of approximately 1,000 to
2,000 mg/1.
The evaporator was operated at about one-half of its
rated capacity (15 gal per hour vs. a capacity of 25 gph).
Samples of distillate and evaporator concentrate were
obtained and analyzed for zinc, free cyanide, total solids,
conductivity and pH. The results of these analyses are
presented in Table I. During closed-loop operation at the
time the samples were taken, a stream of about 1.5 gpm
from the bath was circulated through the evaporator and
back to the bath in order to prevent precipitation of
plating salts in the evaporator. Thus, the evaporator was
operating on a feed very similar in composition to the
bath and producing a concentrate which was more
concentrated than the plating bath. (In addition, the
plating bath during this test appears to be significantly
91
-------
TABLE I
REJECTION RESULTS FOR EVAPORATOR
CURING CLOSED-LOOP OPERATION
l)i\iilltiir Rejection
/1 IK
(\uimlc
lolnl Sululs
Cond \icti\nv
pH
46.000 mil I
90.000 mg, I
404,000 mg/l
160,000 mg I
IM
< O.I mii-1
15 mg/l
< •> mgM
100 mg, I
10.3
> 99.999H' ;
.
99.999
99.8 1'1,',
NOII : OpiTUling conditions 104"
conversion
I-, 27 in Hg viicuiim, 17':;,
higher in zinc than the nominal level given above). The
quality of distillate produced was quite good. Zinc and
total solids concentrations were below their respective
detection limits, but cyanide, conductivity, and
hydroxide ion were detectable. The rejections or removal
efficiencies were quite high; particularly for zinc and total
solids. The quality of distillate was considered quite
suitable for final rinsing.
Total Recycle Tests at 10% of Bath Concentration
Total recycle tests were periodically conducted in order
to evaluate membrane module performance under well
defined conditions of feed concentration (10% of bath
concentration), pressure (700 psi), temperature (75 - K5°
F), and recirculation rate through the modules (10 gpm).
Results for flux as a function of time are shown in Figure
4. The flux was calculated from the measured permeate
flow rate using a surface area of 70 ft2 per module.
(Actual surface areas measured after the field lest for
Modules «2 und »3 were 73 and 69 ft\ respectively.) The
data were corrected to 75° F using the inverse relation
between flux and water viscosity.
Tor Modules tfl and 02 the flux levels were nearly
identical throughout the field demonstration. The flux
gradually declined from 13 gfd to 7 gfd over the first 3,000
hours. Following cleaning at 3,000 hours, the flux
increased to 12 gfd, which is very close to the original
level. Thus the cleaning procedure employed was quite
successful in restoring the flux. It may therefore be
concluded that the major reason for flux decline is
fouling of the membranes.
Results for Module #3 are also presented in Figure 4
(dashed line). The flux starts at a significantly higher level
(20 gfd) but declines more rapidly to a value of 5 gfd at
3,000 hours. The cleaning procedure was ineffective in
restoring the flux of Module #3. Because of its low flux
und low rejections (discussed below) Module #3 was
removed from the system at 3,000 hours.
After cleaning, the system was returned to closed-loop
operation on the actual rinscwater. During the next 1,200
hours the flux for Modules tt I and #2 declined to about 7
gfd. The rote of flux decline was more rapid during this
time period since a coarser grade (20/* vs IM) cartridge
filter was used to pro-filter the feed during this segment of
the demonstration,
Results for zinc rejection during the field
demonstration are shown in Figure 5. For Modules #1
and #2 the zinc rejections agree reasonably well and arc
correlated with a single curve (solid line). The zinc
rejection declined gradually from an initial value of 99%
to 97% after 3,000 hours. Upon cleaning, ihe rejection for
Module tl I increased to nearly 99% while the rejection for
Module #2 increased to about 98%. Thus the cleaning
procedure was successful in restoring the /inc rejection.
Therefore ii is reasonable lo conclude that the loss of/inc
rejection is primarily the result of membrane fouling.
After cleaning the rejection again declined us fouling
occurred.
For Module #3 the /inc rejection dropped off rapidly
to a value of 90% after only 700 hours and remained
reasonably constant between 700 and 3,000 hours.
Cleaning produced u significant increase in rejection
(from 90 to 95%).
The rejection of free cyanide is shown in Figure 6.
Again the results for Modules #1 and #2 agree quite well
throughout the test. For these modules the cyanide
rejection declined slightly—from 98% to 97%- during
the first 3,000 hours. Cleaning had little effect on the
rejection level. However, because of the small loss in
rejection, cleaning would be anticipated to have only a
minor effect on rejection levels. Following cleaning, the
cyanide rejection declined at a more rapid rate, probably
as the result of the increased rate of fouling.
0 wwl II
A «MI »
0 KMI II
r
1 --- .
Pig. 4—Zinc r«|*otlon vi. tupoiur* Urn* •« datarmlnad by total rtoyolt
(••It •( 10% ot bath.
Fig. 8—Hu* at • function ot txpoiura llmi for total raoyola (tilt «t 10% of
bath and 75" l».
92
-------
l,« 1.100 1.000 I,Hi 1,101 I.UO 1,000 <,UD
Pig. C—Frt t cyanide rejection vi. exposure lime •• determined by tola)
recycle tetlt il 10% ol bath.
The cyanide rejection results for Module #3 are also
shown in Figure 6. As for zinc, the cyanide rejection
dropped quite rapidly, from 99 to 85%, during the first
700 hours and appeared to stabilize at about 85% until
3,000 hours. The data point at 3,000 hours (93%
rejection) indicates a substantial recovery in rejection
before cleaning. Since no similar recovery was observed
for zinc and total solids rejections, it is possible that the
high cyanide rejections at 3,000 hours could be attributed
to a sampling or analytical error.
Total solids rejections are presented in Figure 7. The
results for Modules #l and #2 are, as before, almost
identical. There was a gradual loss in total solids rejection
for Modules tt\ and #2 from 95% initially to 90% after
3,000 hours. Cleaning at 3,000 hours produced an
apparent loss in rejection. (A similar loss was also noted
for conductivity rejection.) During operation after
cleaning, the rejection increased to 90%—the same level
as before cleaning. Thus the loss of rejection upon
cleaning was only temporary. Indeed, since the results of
Figures 4-6 indicate fouling and a decline in membrane
performance between 3,000 and 4,200 hours, it is
reasonable to postulate that a similar decline in total
solids rejection occurred during this period. By virtue of
the fact that the rejection at 4,200 hours is the same as at
3,000 hours, it can be concluded that the cleaning actually
improved the total solids rejection. The observed loss in
rejection is probably the result of an interaction between
the citric acid cleaning solution and the membrane
surface. Similar results have been observed with citric
acid in cleaning tests conducted by the manufacturer (7).
These tests consistently showed a loss in rejection after
cleaning, but the rejection then increased over a relatively
short period (5-24 hours) to the level expected for a clean
module. The mechanisms of this interaction is not well
understood, but the rejection loss appears totally
reversible by extensive flushing or by returning the
system to operation on the normal feed. Thus the most
reasonable explanation of the total solids rejection
behavior is that, when the system was returned to nowmrK
operation after cleaning, the rejection increased to a level
probably close to 95% within 24 hours and then
decreased gradually to 90% at 4,200 hours as fouling of
the module occurred.
J I
Fig. 7—Tola! tolldi re|ectlon vi. eipoiure lime at determined by total
recycle leilt al 10% of bath.
The total solids rejections for Module #3 are quite
similar to the /inc and cyanide rejections for this module.
The rejection decreased from 95% to about 80% during
the first 700 hours und remained at about 80% until the
module was removed at 3,000 hours. Cleaning produced
no significant change in total solids rejection for Module
#3.
The close agreement between the results for Modules
# I and #2 would be anticipated for two identical modules
operated in series. By comparison the results for Module
#3 are quite poor. Since the system conversion per pass
was low (high recirculation flow relative to permeate
flow) the feed concentrations to the three modules were
approximately the same; therefore u higher feed
concentration would not account for the poor
performance of Module #3.
A similar rapid loss in performance has been
occasionally noted for some of the earlier PA-300
modules used in water disalination (7). This problem was
traced to a procedure used in manufacturing the
modules. The procedure has since been changed and the
problem thereby eliminated. However, the modules used
in this field test were manufactured before this change,
and it is believed that Module #3 was defective from the
outset of the test.
The level of suspended solids in the zinc cyanide bath
was high compared to the levels observed for copper
cyanide baths (5). A purifier (polysulfide) was regularly
added to the zinc cyanide bath and produced a mud-like
sludge that was removed by filtration, Some of this
sludge was carried over into the rinse tanks and thus into
the RO system. During the first 3,000 hours of the test, I
ju cartridge filters were used and had to be changed
approximately once per week (assuming 100 operating
hours per week). After about 3,000 hours, 20 M cartridge
filter were used. The service time for the coarser filters
was substantially longer (estimated service time - one
month) but the rate of fouling of the modules was greater
with the coarser filters. It is recommended that two
cartridge filters in series- a 20 n filter followed by a I M
filter—be used for prc-filtration of zinc cyanide
rinsewater.
Following the field test Module #2 was cut open and
93
-------
too
0 18,000 40,000 60,000 80,000
TOTAL SOLIDS FEED t«tt0ITMTi«, «a/l
Fig. 8—Dependence of Rux on feed concentration
100,000
90
§ as
80
n
I ZlK
O NOBUtC II
& MODULE 12
_L
0 20,000 40,000 £0,000 80,000
TOTAL SOLIDS TEED CONCENTRATION, mg/1
Fig, 9—Dependence o( rejection on le«d concentration.
100.000
unwound for inspection. The membrane was fouled with
a thin layer of sulfide sludge with the degree of fouling
increasing toward the center of the module. This layer
could be very easily wiped from the membrane surface.
During cleaning at 3,000 hours, a distinct odor of HaS
was noted during recycling of the citric acid solution,
This is presumed to be the result of solubilization of some
of the suifide foulant. This suggests that the ammoniated
citric acid was the active ingredient in the cleaning
procedure and that Titron X-100 surfactant could be
eliminated. Cleaning agents other than citric acid could
work as well or better and should be tested. Of particular
interest would be the use of oxidizing agents to oxidize
the sulfide foulant layer. While the membrane is
susceptible to rapid attack by some oxidizing agents such
as chlorine, it has been shown to be resistant to others
such as chlorine dioxide and chromic acid (6, 7).
In addition to fouling of the membrane, examination
of the module internals revealed some possible
deterioration of the membrane backing material.
Samples of the membrane and backing were returned to
the manufacturer for examination, the finding of which
confirmed that the backing had been deteriorated,
probably as a result of the high concentrations of
hydroxide ion in the rinsewaters (7). However, it is not
clear what effect deterioration of the backing would have
on membrane module performance. No gross effects on
performance were observed during the field test.
Substitute backing materials could be used, but a
development program would be required to
commercialize the PA-300 on a more resistant backing.
Total Recycle Tests at Other Feed Concentrations
Following initial start up of the RO system, total
recycle tests were conducted to determine the dependence
of flux and rejection on feed concentration. Tests were
conducted at various dilutions of the plating bath ranging
in nominal concentration from zero to 20% of the bath
concentration.
Flux results as a function of the total solids
concentration of the feed are shown for Modules # I and #
2 in Figure 8. The results for these two modules are in
very good agreement. (Results for Module #3 were not
consistent with those shown in Figure 8 and have not
been included). As expected, the flux decreases with
increasing feed concentration and approaches a level
generally considered uneconomical at a feed
concentration in the vicinity of 100,000 mg/1. By
comparison the bath concentration is approximately
350,000 mg/1 in total solids. These data illustrate the
problem of using RO to achieve very high
concentrations. The data presented in Figure 8 can be
used in optimizing the degree of concentration that
should be obtained in the RO system prior to
evaporation.
Rejection as a function of the total solids
concentration in the feed is shown in Figure 9 for
Modules #1 and #2, The zinc, cyanide, and total solid
rejections remain essentially constant at 99%, 98%, and
95%, respectively for feed concentrations below about
40,000 mg/1 total solids. At higher feed concentrations
the rejections drop off as expected.
94
-------
Economics
One of the main objectives of conducting a field
demonstration is to provide a basis for evaluating the
economics of the process. Figure lOa shows the flow
schematic for the original two-stage countercurrent
rinsing system. The rinsewater flow rate was measured at
2.0 gpm. The rate of dragout from the bath was estimated
by turning off the rinsewater and measuring the buildup
of zinc and total solids in the first rinse as a function of
time. The calculated dragout rate was 0.01 to 0.015 gpm.
However the parts being plated during this determination
were flat and free-draining and a somewhat higher
dragout rate of 0.02 gpm was considered more typical for
purposes of design. Given these flow rates and ideal
mixing in the rinse tanks, the zinc concentration is
reduced from 20,000 mg/1 in the bath to 2.0 mg/1 in the
final rinse.
Figure I Ob shows the flow schematic, flow rates (in
gpm), and zinc concentrations (in mg/I) for an
RO/Evaporator system designed to give the same zinc
concentration in the final rinse. The flow rates given in
Figure I Ob are for 90% water recovery in the RO system
(ratio of system permeate to system feed. 5.85/6.5 = 0.90).
All of the concentrate from the RO system is converted to
distillate in the evaporator, and an equal flow (0.65 gpm)
of plating bath is used to purge the concentrated
chemicals from the evaporator and prevent precipitation.
The stream returning to the bath is about 3% higher in
concentration than the bath, and precipitation in the
evaporator would occur only if there were some
constituent in the bath (e.g., carbonates) at a
concentration very close to its solubility limit. The
permeate and distillate flow rates given in Figure I Ob
(5.85 and 0.65 gpm, respectively) are considerably greater
than the corresponding flows in the system demonstrated
(I-1.5 and 0.2 gpm, respectively).
One of the most important of design criteria is the flux
for the RO system. The flux depends on the operating
pressure, temperature, feed concentration, and the flow
rate of concentrate from the module. The system would
be designed to operate at 800 psi, maximum
recommended operating pressure for the modules. The
design temperature would be 77° F. At higher
temperatures the flux would increase, and the rejection
would remain essentially the same. Thus the performance
of the RO system would improve with increasing
temperature, although the membrane life may be
shortened. For the design case shown in Figure lOb (i.e.
90% RO system conversion) the total solids
concentration in the feed to the first RO module is
calculated to be 5,500 mg/1 and the concentrate
withdrawn from the final module is 10,600 mg/1. Thus
the average feed-side total solids concentration is about
8,000 mg/1. From Figure 8 the flux for a new module at
this feed concentration would be about 20 gfd (at 700 psi
and a recirculation flow rate of 10 gpm). From Figure 4
the flux declines to about half of its initial value over an
operating period of about 700 hours (exposure time:
3,000 hours). Thus it would seem reasonable to design the
9.91. mm
JLJLj
28.000 •)/1
3»,«0 mtf
if, 8i
In 209
TS JM
? 0 9P»
2* 1.9
15 »
t. PrtMM H«*fs|
9.45
Is. €Ja»*4-l*>p rinsing ijrftcm
Fig. 10—Plows and concentration* for open and closed-loop rinsing.
system for a minimum flux of 10 gfd. At this flux the rate
of permeate production is approximately 0.5 gpm for
each module (area = 70 ft2). Based on the recommended
ratio of concentrate flow to permeate flow (10 to I) the
rate of recirculation for the RO system would be 5 gpm as
shown in Figure I Ob. (This recirculation rate is only half
of that used during this field demonstration and could
result in a slightly lower flux than measured; however the
higher operating pressure—800 vs 700 psi—would
compensate by increasing the flux.)
Rejection is also an important parameter in the design.
Based on the results of Figure 9 at a total solids
concentration of 8,000 mg/1, the zinc and total solids
rejections would be 99% and 95%, respectively. From
Figures 5 and 7, fouling of the modules can be expected to
result in a decrease in zinc rejection from 99 to 98%. Thus,
for the design, the minimum zinc and total solids
rejections were selected as 98% and 90%, respectively.
The RO system can be designed to operate at any
desired conversion within reason. At low conversion the
capital and operating costs are dominated by the
evaporator; at high conversion, capital and operating
costs are dominated by the RO system. At some
intermediate conversion, the total operating cost should
pass through a minimum. Material balance calculations
were performed for the system of Figure lOb using
various RO system conversions. (Results are shown only
for the 90% conversion case.) Capital and operating costs
95
-------
were then developed for each conversion in order to
determine the optimum.
Table 2 gives the capital costs for the RO unit, the
evaporator unit, and the total system, for various RO
system conversions. The material balance relationships
and the RO module rejection were used to calculate the
permeate flow and the evaporator capacity required to
give a zinc concentration of 2 mg/1 in the final rinse. At
zero conversion in the RO system (i.e. no RO system) the
entire treatment load is handled by the evaporator. For
this case the evaporator must produce 2.0 gpm in order to
provide the same degree of rinsing as the original 2-stage
countercurrent system. Cost details are noted at the foot
of Table 2. The lowest capital cost occurs when the
evaporator is used to handle the entire treatment load.
For RO system conversion between 70 and 90%, the total
system cost remains at about $62,000.
Total annual operating costs were also calculated for
each RO system conversion. The breakdown of operating
costs for a conversion of 90% is shown in Table 3. Specific
costs and assumptions are noted at the foot of Table 3.
The costs are based on operating 100 hours per week
(Monday morning through Friday afternoon) and 50
weeks per year for a total of 5,000 operating hours per
year. Similar operating costs were developed for other
RO system conversions.
The electrical costs for the RO system are strongly
dominated by the requirements for the high pressure
pump. The use of a positive displacement pump was
assumed with a combined pump/ motor efficiency of
75%. In addition, since a new (or clean) module would
produce twice the design flux, the RO system could be
operated at half the design pressure (i.e., 400 psi). As
fouling occurs the operating pressure would be increased
to maintain the design flux, and the system would be
cleaned when the operating pressure reached 800 psi.
Thus an average feed pressure of 600 psi was used in
calculating the power costs of Table 3.
When operating with the 1/z cartridge pre-filters, it was
necessary to change the two parallel cartridges after
about 100 hours of operation. With the 20ju filters, the
pressure drop was still quite low (< 3 psi) even after 300
hours of operation. With two parallel passes each having
a 20/i and a lju cartridge in series, it is estimated that the
four filters would last for about a month (400 hours).
Monthly replacement was therefore assumed for the
economic calculations.
With Ifj. pre-filtration, cleaning was required after
about 700 hours of operation. During this time three
modules were in use. However for the design cases shown
in Table 2, anywhere from 6 to 18 modules would be used.
It is reasonable to postulate that the extent of fouling
would vary inversely with the membrane surface area.
Thus a cleaning frequency of once every four months
(1600 hours) was assumed.
Membrane life is a very important parameter in the
economics. As mentioned above, chemical attack of the
membrane or other module components would be
expected to depend on total time of exposure to the
rinsewaters rather than operating time per se. The two
field demonstration modules were exposed to the
rinsewaters for a total of 4,200 hours. This is close to the
5,000 hours operating time per year taken as the basis for
calculating the operating costs. If the system were
designed to purge the modules with distillate on shut-
down, the effective exposure time would also be about
5,000 hours. Thus a membrane life of one year would be
virtually assured. However, it is likely that the membrane
life would be considerably longer than one year. During
the field demonstration the modules produced only a
fraction of the permeate flow that would be produced by
a system designed to meet the rinsing constraints of
Figure lOb. Thus the feed concentration to the field
demonstration modules was considerably greater than
would be seen by a larger capacity system. Furthermore,
during periods when the demonstration system was not
TABLE 2
CAPITAL COSTS FOR VARIOUS RO SYSTEM CONVERSIONS
RO
System
Conversion
0
0.70
0.80
0.90
0.95
Required
Permeate
Flow
gpm
2.575
3.625
5.85
8.91
Required'
Membrane Required'
Area No. of
ff Modules
371
522
842
1.283
6
8
12
18
Membrane'
Module
Cost
5
3,780
5,040
7,560
11.340
Housing"1
Cost
$
1,700
2,550
3,400
5,100
Total Cost' Required' Total Cost Total
for RO Evaporator for System
System Capacity Evaporator Cost
$ gph 5 5
21.780
23,890
28.560
34.040
120
66.2
54.4
39.0
28.1
44.129
39.199
39,199
33.880
33.880
44.129
69,979
63,089
62.440
67.920
(a) Design flux = 10 gfd.
(b) Based on area of 70 ft"' per module.
(c) Based on S630 per module (Abcor, Inc.)
(d) Based on $850 per 3-module housing (The Permutit Co.. Inc.).
(e) Based on system cost of $ 15.000 (Osmonics, Inc.) for system W / O modules, housings, and high-pressure pump. Pump/ motor cost = S1,300
for< 4 gpm permeate; 52,600 for> 4 gpm permeate (Wanner Engineering, Inc.).
(0 Double effect evaporator with cooling tower package. Based on rated capacities of 200 gph (544,129). 100 gph ($39,199). and 50 gph
($33,880).
96
-------
operating, the concentration across the membranes
equilibriated resulting in very high concentrations on the
permeate side. This situation would accelerate attack of
the membrane backing material and other permeate-side
components. Purging the system on shut-down would
largely eliminate this source of module deterioration.
Item
TABLE 3
TOTAL AND NET OPERATING COST
FOR 90% RO SYSTEM CONVERSION
(5,000 OPERATING HOURS PER YEAR)
RO Evaporator Total
System System System
5 ' $ ' J
Capital Amortization (a) 2,100 3,388 5.488
Direct Operating Costs
Steam @ J3.50/
lOOOIbs(b) - 3,760 3.760
Electrical @ S0.0474/
kw-hr(c) 1.008 1,100 2,108
Operation & Mainte-
nance @ SlO/hr
including fringe
benefits (d) 960 960 1,920
Cartridge Filters &
Cleaning Chemicals (e) 240 240
Membrane Replace-
ment (2-year life) 3,780 3.780
Total Direct Operating
Cost 5,998 5,820 11.808
Total Annual Operating
Cost 8,098 9,208 17,296
Credit for Bath
Recovery @ S0.47/
gal (0 (2,820)
Credit for Water
Recovery @ S0.45/
100 ft' (361)
Credit for Cyanide
Destruction @ S4.05/
Ib CN (g) (6,440)
Credit for Solid Waste
Disposal @ S29/
drum and 25% solids
in sludge (h) (354)
Total Annual Credits (9.975)
Net Annual Operating
Cost 7.321
(a) Straight-line depreciation over 10 years with zero salvage value.
(b) Based on actual cost for No. 4 fuel oil of J0.393/gal, heating
value of 140,000 Btu/gat, and a boiler efficiency of 80%.
(c) Based on actual cost for October 1978.
(d) Based on actual maintenance labor rates.
(e) Four cartridge filters changed once per month at average cost of
S4.68 each. Cleaning three times per year with 6 IDS citric acid per
cleaning at S0.82 per pound.
(0 Chemical costs: zinc $0.445/lb; sodium cyanide $0.51/Ib; caustic
$O.I85/lb; brightener $6.792/gal.
(g) Based on 8 Ibs NaOCI per Ib of CN with no addition of caustic
(already present in rinsewater). Cost for 15% NaOCI solution =
S0.665/gal.
(h) Based on sludge centrifuged to 25% solids and hauled in lots of
80 55-gal drums.
Considering these factors, it is not unreasonable to
project a two-year membrane life as assumed in Table 3.
Operating and maintenance labor for the RO system
was assumed to require 1 day per month. This would
include system start-up on Mondays, shut-down on
Fridays, cartridge filter replacement, membrane
cleaning, and other maintenance as required.
Steam consumption for a double effect evaporator
operating as shown in Figure lOb with temperatures of
130° F and 110° F in the first and second effects,
respectively was calculated to be 0.66 Ibs steam/Ib
distillate. Electrical requirements for operation of the
cooling tower, evaluation of the evaporator, pumping the
various output streams, and miscellaneous usage were
obtained from the manufacturer (4.64 kw, 8.64 kw, and
16.64 kw for double effect capacities of SO, 100, and 200
gph, respectively). As for RO, operation and
22,000
20,000
18,000 -
16,000
14,000
8
to
S 12.000
10,000 —
8.000 —
6.000 —
0.7 0.8 0.9
RO SYSTEM CONVERSION
Fig. 11—Annual operating costs lor various RO conversions.
1.0
97
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maintenance for the evaporator was assumed to require
one man-day per month.
As shown in Table 3, the direct operating costs
(excluding amortization) are about $6,000 per year each
for the RO system and the evaporator for a total of about
$12,000. The total annual operating cost including
amortization is $17,300. Table 3 also gives the
breakdown of credits resulting from recovery of the
rinsewater. The largest credit results from a reduction in
the amount of cyanide to be destroyed. The credit for
sludge disposal was calculated on the basis of the weight
of zinc hydroxide produced by precipitation of the
dragout and is probably significantly less than for plating
shops which do not have solids dewatering equipment.
The total annual credit for rinsewater recovery is about
$10,000, which leaves a net operating expense of $7,300
per year for the recovery system.
Operating costs were also determined for other RO
system conversions and are shown in Figure 11. For
conversions ranging from 70% to 95% the RO operating
costs increase and the evaporator operating costs
decrease. The total operating cost passes through a
minimum at an RO system conversion of 90%. Using an
evaporator alone for rinsewater recovery (zero percent
RO system conversion) the total annual operating cost
including amortization is about $20,900. For the
optimum combination of RO and evaporation, the total
annual operating cost is approximately $17,300 which
represents in annual savings of $3,600.
In considering the impact of these numbers it should be
emphasized that the recovery system was designed to
meet a given rinsing criteria for a two-stage
countercurrent rinsing system. Recovery system costs
could be reduced significantly by using more rinsing
stages. For manual operations, additional rinse tanks
could be inserted in the line, and for automatic
operations, over-the-tank spray rinses could be used. In
addition, consideration should be given to working with
higher rinse concentrations where rinsing is not critical.
The costs for recovery provide a substantial incentive for
reducing the rinsewater flow by simple, inexpensive
techniques.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the cooperation
and support of Bruce Warner, president of New England
Plating Co. in providing the field site for the
demonstration, support personnel to assist in installation
and cost information for operation and waste treatment
at New England Plating Co. Financial support for the
program was provided by EPA (Grant No. R805300) and
AES (Research Project No. 45). Technical support
during the program was received from the EPA Project
Officer, Mary Stinson, and from the AES Project
Committee: Jack Hyner, Joseph Conoby, Charles Levy,
James Morse, and George Scott.
REFERENCES
I. Skovronek, H. S., and M. K.. Stinson, Advanced
Treatment Approaches for Metal Finishing
Wastewaters (Part II). Plating and Surface Finishing,
64(11): 24-31, 1977.
2. Anon., Recovery Pays! Plating and Surface
Finishing, 66 (2): 45-48, 1979.
3. Hall, E. P., D. J. Lizdas, and E. E. Auerbach, Plating
and Surface Finishing, 66 (2): 49-53, 1979.
4. Donnelly, R. G., R. L. Goldsmith, K. J. McNulty, and
M. Tan, Reverse Osmosis Treatment of
Electroplating Wastes, Plating, 61 (5): 432-422, 1974.
5. McNulty, K. J., R. L. Goldsmith, A. Gollan, S.
Hossain, and D. Grant, Reverse Osmosis Field Test:
Treatment of Copper Cyanide Rinse Waters. EPA-
600/2-77-170, U. S. Environmental Protection
Agency, Cincinnati, Ohio, 1977. 89 pp.
6. McNulty, K. J., P. R. Hoover, and R. L. Goldsmith,
Evaluation of Advanced Reverse Osmosis
Membranes for the Treatment of Electroplating
Wastes. EPA-600/8-78-010, Environmental
Protection Agency, Cincinnati, Ohio.
7. Personal Communications, Dr. Robert L. Riley,
Fluid Systems Division of UOP, San Diego, CA.
98
-------
Membrane Processes for Metal Recovery
From Electroplating Rinse Water
John L. Eisenmann*
Investigations into the feasibility of two new
applications of membrane processes for the recovery of
plating metals from electroplating rinses have recently
been initiated with the aid of EPA demonstration grants.
These are the recovery of chromic acid from a decorative
chrome plating line by electrodialysis and the removal of
nickel from a Watts-type line via Donnan Dialysis. Both
of these processes function by transferring metal ions or
metal containing ionic complexes across ion-exchange
membranes. This ionic transport is from the rinse water
on one side of the membrane to a receiving solution on
the opposite side. The enriched solution can then be
returned to the plating tanks or otherwise treated more
conveniently or economically than the rinse stream itself.
A major difference between the two processes is that the
driving force for electrodialysis is an impressed electrical
potential across the membrane while Donnan dialysis
depends on maintaining a cross-membrane
concentration gradient. As normally operated,
electrodialysis functions as a demineralization process,
removing and concentrating both anions and cations
from the treated solution. Donnan dialysis acts as a
continuous ion-exchange process, replacing the ionic
constituent of interest with an innocuous or a less
valuable species of the same charge type. Lately,
electrodialysis appears to have become more familiar to
the electroplating industry but Donnan dialysis has seen
little, if any, exploitation in this area. One of the goals of
the demonstration programs is to make potential users
aware of the technology and to indicate where it might
best be applied. Each process will be discussed in more
detail below and some of the laboratory and field results
to date described.
Electrodialysis (ED) is a membrane process which can
be used for the separation, removal or concentration of
ionized species in water solutions. These operations are
accomplished by the selective transport of the ions
through ion-exchange membranes under the influence of
an electrical potential (VDC) applied across the
membrane. The ion-exchange membranes are the key to
the process and two types are required. Cation-exchange
membranes, which are permeable only to the positively
'John L. Eisenmann
Chemical Recovery Systems
Division of The Lea Manufacturing Co.
176 King Street, Hanover. MA 02339
charged cations in the solution, and anion-exchange
membranes which permit only the passage of negative,
anionic species. Physically, both membrane types are
formed as thin sheets of ion-exchange material, usually
reinforced by a synthetic fabric backing to provide the
necessary strength. Thickness can vary between one-
tenth to almost on millimeter and membrane sheets
larger than one meter square are commonly used. The
resin matrix is usually styrene or vinyl-pyridine
copolymerized and cross-linked with divinylbenzene and
the exchange capacity imparted by sulfonic acid, or
quaternary ammonium or pyridinium groups covalently
bonded to the polymeric backbone. In such membranes,
95-99% of any electric current flowing is carried by the
mobile counterions.
In the usual configuration for electrodialysis,
alternating cation- and anion-selective membranes are
arrayed in parallel between two electrodes to form an ED
multicell or membrane "stack" (1,2). Especially designed
spacer/gaskets separate the membranes by forming leak-
tight, flow directing compartments between adjacent
membranes, and the whole assembly is held in
compression by a pair of end plates and tie-rods or other
clamping device. The compartments or cells formed by
the spacers are typically I-1.5 mm thick and direct the
solution fed to the cell over the surfaces of the membranes
either in a tortuous path or sheet flow pattern. The flow
path usually contains a plastic screen or supporting
baffles to ensure separation of the membranes and induce
turbulent flow. A stainless steel sheet is commonly used
for the cathode and platinized titanium for the anode.
Other necessary equipment such as pumps, power
supply, filters and piping is conventional, but plastic
components are used wherever possible to avoid
corrosion, stray electrical currents and contamination of
the process streams.
Conventional arrangement and operation of an ED
multicell are shown schematically in Figure I. The
process or feed solution which is to be depleted of ions is
fed to the even-numbered or diluting cells and the ion-
receiving or concentrating solution passes through the
odd-numbered cells. Usually the same solution is used for
both streams but the concentrating solution is
volumetrically 10% to 20% of the feed and may be
recycled to minimize the amount of discharge and better
control the pressure differential. The repeating stack unit
of a cation-selective membrane, a diluting spacer, an
99
-------
Cathode
A
\ 1
1
A c
^
1
^ A c
\
1
1
JC
\ 1
t
t C
Aftl C/
(
A
•k i
A l\ A | l\. A !
X
Cell-pa
One
-pair
Anode
"*
Feed
Return
Concentrate
\
Concentrate
collection or
disposal
Electrode rinse
reservoir
Fig. 1—ED Multicell Schematic.
C- Cation selective membrane
A- Anion selective membrane
M_ Cations
X~ An ion s
anion-selective membrane, and a concentrating spacer is
termed a cell-pair, and ED equipment can be
characterized by indicating the number of cell-pairs
comprising a multicell. Industrial stacks generally
contain 50-300 cell-pairs although a recent report has
described a multicell containing over 900 cell-pairs
especially designed for large-volume brackish water
demineralization. Solution is distributed to, and
collected from, the cells by two internal hydraulic
circuits; one for the concentrating cells and one for the
diluting cells. As indicated in Figure I, the passage of a
direct current through the stack causes the ions in the
solutions flowing through the stack to move in the
direction of the oppositely charged electrode. Positive
cations in the feed stream are attracted to the negative
cathode and pass from the diluting compartments,
through the cation-exchange membranes on the cathode
side of the cell, into the concentrating compartments,
where they accumulate, since their further transport is
prevented by interposed anion-selective membranes.
Negative anions move in the opposite direction,
traversing the adjacent anion-exchange membranes but
blocked by the cation-exchange membrane next
encountered. Flow velocity of the solutions in the cells
varies with the stack type within the range 5-50 cm/sec. A
hydraulically separate stream is used to rinse the
electrode compartments and remove the gases formed by
the electrode reactions:
at the cathode: 2 H2O + 2e~ - H2t 4- 2OH
at the anode: H2O - 2e~ - 1/2 O2t + 2 H+ or
cr-c'- i/2Cht
The electrode rinse is usually acidified to prevent
increases in pH and resulting precipitation of insoluble
species. Part of the feed or concentrate solutions can be
used as the rinse or a special rinse solution prepared and
recycled independent of the process streams. Use of the
electrodialysis multicell concept makes it possible to
obtain a deionizing effect equal to many times the
electrical equivalents passed. This feature and the
availability of physically strong and highly selective ion-
exchange membranes combine to make electrodialysis
economically viable, notably for the desalination of
water.
Ohm's and Faraday's Laws apply to the
electrochemical phenomena occuring within the multicell
and several mathematical relationships can be used to
characterize electrodialysis equipment and to compare
different types of apparatus. Current efficiency, also
called coulomb efficiency, indicates the effective
utilization of the current passing through the membrane
stack for transfer of the ion of interest. It is calculated
from feed stream flow rate and inlet and outlet
concentrations, current through the stack, and number of
cell pairs.
Another important consideration is the relationship of
the stack limiting current density to solution
concentration and flow velocity. If the limiting current
100
-------
density is exceeded, polarization at the membrane
surface will occur due to local ion depletion and pH
changes, precipitation in the cells, high electrical
resistance and loss of current efficiency may result. To
avoid polarization operating current densities are held at
conservative levels, often one-half the limiting value.
Turbulance promoters and high fluid velocities in the
feed cells are used in an effort to maximize the allowable
current through the stack.
For the treatment of plating rinse water, rather small,
mobile ED modules have been developed for use in the
usually space-limited plating rooms. A commercial unit
is shown in Figure 2. It measures approximately 42"x 52"
* 27" and contains all controls and equipment necessary
for operation. Feed and return piping for recirculation of
a still or reclaim rinse and a single electrical connection
are all that are necessary to complete installation. The
membrane stack shown at the lower right of the module
contains 35 cell-pairs and can vary in size in order to
provide the capacity required to remove an amount of
plating salts equal to that dragged into the rinse from the
plate tank(s) and thus hold the reclaim solution at a
constant metal concentration. The multi-cell differs from
conventional ED equipment in that the concentrate cells
are dead-ended for maximum concentration and
simplified operation.
In order to extend the electrodialysis concept to the
treatment of chrome plating rinses, one of the first
considerations was the chemical resistance of the
membranes. To check this, commercially available
anion-exchange membranes were immersed at room
temperature in chromic acid plate solution and sections
removed for testing after 7, 14, 42, and 69 days. All
sections were leak-tight and appeared to have lost none of
their physical strength although there was a slight
roughening of the surface. Exchange reactions indicated
that the ion-exchange groups were not affected by the
acid. Laboratory electrodialysis experiments were then
conducted with a five cell-pair stack similar in size and
operating characteristics to the multicell shown in Figure
2. Simulated chromic acid rinse solutions were prepared
by dissolving chromium trioxide in tap water.
Electrodialysis of these solutions over a range of current
densities gave the representative results in Table I. All
samples were taken after several hours operation at each
operating condition. Rinse temperature was 78-91° F.
The data indicate that chromic acid can be concentrated
from dilute aqueous solutions at least to about lQr'c of the
strength of many chrome plate solutions and may be
useful for direct return to the plate tanks. Figure 3 plots
the increase in product concentration with current
through the stack, a result consistent with data from
other electrodialysis concentration experiments. (3) The
attainable chromic acid concentration in the product
appears to be leveling off at 170-180 g, 1 and the
product feed concentration ratio decreases with
increasing feed concentration. During the course of these
experiments the membranes were in contact with varying
concentrations of chromic acid over a period of 2-3
months without obvious deterioration or loss of
selectivity; tending to confirm the life test results
described above.
A fifty cell-pair demonstration module was next
constructed for testing on an actual chrome plating line
operated by Seaboard Metal Finishing Co. of West
Haven, CT. This module is show n on-site in Figure 4 and
was installed to recirculate a dead rinse located between
the plate tanks and the counterflow rinses. Figure 5 is a
schematic of this arrangement. Recirculation rate
through the ED stack was 20-25 G PM and dilute sulfuric
acid was used an an electrode rinse solution. Initially, the
objective was to determine it the membranes and other
materials of construction would he sufficientlv resistant
Fig. 2—Electrodialysis Module lor Metal Recovery.
Electrodialysis of
Run
I
2
3
4
s
Current
Dentil v
10 ma cm
12
14
16
IS
Table 1
Simulated Chromic Acid Rinses
Feed Com:
K 1 CrO*
.37
.32
1.24
.9K
.70
Proiluel
Com:
v 1 CrOi
61
106
143
167
174
ProJut l
Rinse Ratio
165
331
IIS
170
249
101
-------
-
,
Wo rk [ '
10 15
Current , aaperes
Fig 3-Chromlc Acid Eleclrodlalyjli
Concentrated
Product
Fig. 5—ED Treatment ol Chrome Line.
Fig. 4—Eleclrodialysls Unit on Chrome Line.
Fig. 6—Chrome Product Concentration.
to exhibit a reasonable life, to see what operating
conditions must be used, to decide what modifications
must be made to optimi/e chrome recovery during later
stages of the project and to familiari/e the plating room
personnel with operation of the electrodialysis
equipment. The recovery unit was to run directly on the
drag-out solution without any adjustment in or
accommodations by the normal plating operation.
During this time the unit was run for approximately 250
hours over a period of more than two months. Operation
was during the day shift of a three-shift operation.
Concentrations ol product samples taken at the end ot
each operating run together with the operating currents
are plotted in Figure 6. During the first part of the period
the current on the stack was increased slowly to a
maximum of 20-21 amps at Day 10, where it was
maintained for the remainder of the period. Product
concentration also increased, as expected from the
laboratory data, and remained relatively high in the 160-
212 g, I chromic acid range until Day 26 when it fell
sharply. The chief operating difficulty during the period
was the high temperature acquired by the rinse solution
due to heating by the pumps and the DC current applied
to the stack. Most of the time it was significantly greater
than 100 K the recommended maximum operating
temperature, and caused extensive slippage between the
102
-------
stack spacers and membranes, eventually leading to
external and internal leakage. It is to this leakage that the
sharp drop in product concentration is attributed and,
indeed, the highest observed rinse temperature of 118°
was reached on the previous day. Rinse concentration
data during this operating period are incomplete but were
in the 50-70 g/1 CrOa range, giving product/feed
concentration ratios of 2-4. These ratios can, of course,
be markedly improved by operating simultaneously with
the plating operation to prevent chrome buildup in the
rinse and/or increasing the stack capacity as required.
At this point the test program was interrupted for
equipment inspection and evaluation, construction and
installation of a new stack designed to minimize slippage
problems, and installation of a cooler in the rinse tank.
Disassembly of the stack revealed no general failure of
the membranes but several were torn and wrinkled due to
displaced spacers. Others had developed pin-holes. Some
spacers had extruded to partially block the flow path and
manifolds and there was a general misalignment of the
stack plies, again, probably attributable to the high
temperatures. At this time, or at subsequent re-startup
attempts, all wetted stainless-steel flowmeter fittings had
to be replaced, viton "O" installed in all unions and filters
and a replacement plastic impeller housing for the feed
pump was required. The second test period was started a
few weeks ago but no correlated data is yet available.
Plans are for the ED unit to run concurrently with the
plating shifts and to increase recovery capacity by
increasing membrane area with a larger stack or
additional units. Lower rinse concentrations should then
be able to be maintained. With the addition of the cooler
in the rinse solution, higher current densities can also be
explored. The outlook for use of ED for chromic acid
recovery is promising but it appears that high current
densities will be required to obtain a product of plating
concentration, that cooling will be necessary and that,
relative to treatment of other bath types, more membrane
area will be needed for equivalent metal recovery.
The second membrane system being examined for
potential usefulness to the electroplating industry is
Donnan dialysis. This process uses the permselective
properties of ion-exchange membranes to establish a
Donnan equilibrium between two solutions of
electrolytes separated by the membrane. In contrast to
electrodialysis, only one type of membrane is used; either
cation- or anion-permeable. For example, in the case of a
cation-exchange membrane, the anions in the two
solutions are prevented from inter-diffusing across the
membrane but the mobile cations will redistribute
themselves between the two solutions on either side of the
membrane until equilibrium is reached and the ratios of
all similarly charged cations are equal:
Any multivalent ions present in the solutions will
equilibrate at higher ratios than the monovalent ions.
The driving force for the cation exchange is the system's
displacement from the equilibrium ratios and can be
controlled by manipulation of the solution
concentrations. If the concentration of one cation species
is substantially increased in, say, the left or stripping
solution, the total cation concentration is maintained due
to the impermeability of the membrane for anions and
the principle of electroneutrality as applied to the solutes.
However, in order to approach equilibrium, the net effect
is the diffusion of any other cationic species in the right-
hand solution from right to left across the membrane,
against the concentration gradient, to ultimately reach a
concentration many times that remaining in their original
solution. They are replaced by counter-diffusion of the
added cation. The major variables affecting the transfer
rate are temperature, concentration and solution flow
characteristics at the membrane face. In practice,
membrane configuration can be plate-and-frame (similar
to the ED multicell), tubular or hollow fiber and the
process regarded as a continuous ion-exchange system.
The feasibility of the process has been examined in the
laboratory for the separation and concentration of
uranyl and lanthanum ions (4), water softening (5),
nutrient removal from secondary sewage effluents (6)
and, in the present case, nickel removal from plating
rinses. The early tests of nickel solutions were performed
on plate-and-frame apparatus adapted from the ED
membrane stack shown on the module in Figure 2 and
schematically in Figure 1. Commercial cation-exchange
membranes in sheet form were used. Dilute nickel feed
solution was pumped repeatedly through a single feed cell
and 0.5-1 N H:SO.i stripping solution recirculated
through two flanking concentrating cells. Typical results
are shown in Table II.
As can be seen, a 20% reduction (% cut) in nickel per
pass through the unit was realized in the feed solution by
exchange with strip solution hydrogen ions and the
recovered nickel was concentrated in the strip solution up
to 50 times its original feed concentration. In another
experiment a sulfuric acid stripping solution was
recirculated for 40 hours against a once-through feed
solution held between 25 and 50 mg/1 nickel. The strip
was maintained at 1.0 - 1.5 normal by the periodic
addition of acid but no other adjustments were made. At
the end of the experiment the nickel concentration in the
(Gl/Cr)' ' = (Q./C,,)'" = (Ckl/Ckr)'" = K
where i, j, and k are cationic species, z their valence, C
their concentration and r and 1 refer to the left sides of the
membrane.
TABLE II
NICKEL RECOVERY BY DONNAN DIALYSIS
Ni Feed
mg/l
in
30
24
20
13
Cone..
our
24
19
16
10
% Cut
20
21
20
23
Ni Strip Cone
mg/l
710
780
830
870
Strip /Feed (in)
Cone. Ratio
24
33
42
67
103
-------
3.0 -
2.0 -
0.5
5 10
Fig. 7—Nickel Recovery by Donnan Dialysis.
is
Hours
strip had increased to 14 g/1, a concentration ratio of 300,
without any decrease in transfer rate or percent removal,
indicating no significant decrease in driving force. Feed
pH was 1.75 to 6.0 during the experiment.
If, in addition to the strip, the rinse or feed solution is
also recirculated, extremely low residual nickel
concentrations can be attained with Donnan dialysis.
Figure 7 is a plot of the nickel concentration in a
simulated rinse where an initial concentration of 4 mg/1
nickel was reduced to .07 mg/1 after 29 hours continuous
dialysis. Again, only a single cell was used and much
more rapid removal rates would be anticipated with an
increase in membrane area. Higher initial concentrations
could also be easily treated at the expense of additional
treatment time or equipment size. It is, of course, possible
and perhaps sometimes desirable to flow both feed and
strip solutions through the exchanger on a once-through
basis. The data demonstrate the possibility of polishing
some plating effluents to fractional ppm with a very
simple technique and offers the hope of meeting very low
effluent standards.
We have also performed some Donnan dialysis work
using ion-exchange membranes in tubular form. The
tubes were made by DuPont from their Nafion ion-
exchange resin and had an inside diameter of .025". A
shell and tube exchanger containing about 380 individual
tubes, or 13 ft2 of membrane area, was used. The aim was
to verify the effects of certain operating variables on
nickel transport rate. Results are shown in Figure 8 where
JO
r»d riow, cm
Fig. 8—Donnan Dialysis Transport Rate vs. Flow Rate.
flux in g/hr/380-tube module is plotted versus total feed
flow rate. Each curve represents a fixed nickel
concentration and at each concentration level the flux
increases with flow rate. This is typical of film-controlled
membrane processes where the thickness of the stagnant
layer at the membrane surface can be reduced by
increasing fluid velocity. The increase in flux with bulk
solution concentration at equivalent flow is also
consistent with a film controlled process where diffusion
to the membrane face is critical.
On the basis of the laboratory results a Donnan
dialysis unit was constructed for field testing to
demonstrate nickel recovery from the rinse water on a
Watts-type nickel plating line. The unit consists of four
vertically mounted shell and tube Nafion exchangers
fabricated by DuPont and piped to be able to run in
parallel or in series, plus two auxiliary tubes arranged for
series flow only. Each tube provides 20 ft2 of membrane
area. A schematic of the feed side hydraulics only is
shown in Figure 9. Strip solution is always up,
0 ....
D m..,
O
Fig. 9—Feed Side Flow Schematic.
104
-------
Fig. 10—Tubular Donnan Dialysis System.
Fig. 11—Donnan Dialysis System on-slte.
counterflow and parallel. Individual valves, pressure
gages, flowmeters and filters control the flow through
each tube. A photo of the completed unit undergoing
hydraulic testing is shown in Figure 10. Pumps for feed
and strip solutions are mounted at the rear of the unit.
Installation on-site was completed only about two
months ago. In operation, the first rinse of a counterflow
sequence, currently averaging 0.5 g I nickel, is
recirculated through the tube-side of the modules and a I-
2 normal acid strip pumped through the shell side from a
separate reservoir. Nickel-laden strip solution is to be
used to replenish the plate tanks, as required, and the acid
concentration renewed daily. Figure I I is a view of the
installed unit. The strip reservoir can be seen in the rear.
Preliminary results are consistent with the laboratory
tests in yielding a nickel transfer rate of about 2 g/ hr/ ft2
depending chiefly on variation in rinse concentration.
After collecting preliminary data on the performance
of the individual tubes and checking the several possible
operating modes, the unit will be adjusted to optimize
nickel recovery and minimize counterflow volume. The
final results will be used to determine what type of
recovery operation is best suited for Donnan dialysis and
as a basis for design of a prototype commercial unit. One
interesting concept is to use Donnan dialysis as the final
step in a sequence of treatment processes to produce very
low contaminant levels in the final effluent. Processes
such as electrodialysis, which have relatively higher
recovery rates and more concentrated products would do
most of the reclaim work. In any event, Donnan dialysis
seems certain to become a useful metal recovery and
pollution control technique.
REFERENCES
I. Wilson. .I. R. "Deminerali/ation by Electrodialysis",
Butterworths. London (I960).
2. Eiscnmann, J. L.. and Leit/. F. B.. "Electrodialysis" in
"Physical Methods of Chemistry - Part II B: Electro-
chemical Methods", A. Weissberger anddB. Rossiter,
Eds., Wiley-Interscience. New York (1971).
3. Nishiwaki. T.. "Concentration of Electrolytes Prior to
Evaporation with an Electromemhrane Process: in
"Industrial Processing with Membranes". R. E. Lacy
and S. Loeb, Eds., Wiley-lnterscicnce, New York
(I972).
4. Wallace, R. M., I & EC Process Design & Dev., 6, 4,
423 (I967).
5. Smith. J. D. and Eisenmann, J. I... Ind. Water Eng.. 1,
9, 38 (1970).
6. Unpublished data.
105
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An EPA Demonstration Plant For Heavy Metals Removal
By Sulfide Precipitation
Murray C. Scott*
The Holley Carburetor Company, a Division of Colt
Industries, Paris, Tennessee was awarded a grant by the
EPA to demonstrate the effectiveness of a new approach
to removal of heavy metals from waste streams by sulfide
precipitation. The process, called Sulfex , was
developed by the Permutit Company. Before the process
was demonstrated at Holley Carburetor, preliminary
pilot plant work was done by the Permutit Company at
their research facilities. The work was done under a grant
made to the National Association of Metal Finishers by
the EPA.
The surfaces of the carburetor castings are of either
zinc or aluminum and are chemically treated according to
finishing specifications established by the automotive
industry. A "Udylite" automatic rack line dips the
castings into various treatment and rinse water tanks
according to a pre-arranged program. The water rinses
following the treatment tanks are the source of
contaminated wastewater which must be treated before
discharge into the city of Paris sewer system. Figure No. 1
illustrates the automatic line. Rinse flow is on the order of
35 gpm.
There are three basic cycles of treatment: (1) zinc
chromate, (2) deoxidize, (3) aluminum chromate.
Composite samples of rinse water were collected during
each cycle and analyzed. The analytical results obtained
are shown in Table No. 1. For design purposes these
concentrations were increased by 20% as a factor of
safety.
Two metals, chromium and zinc, had to be removed
before discharge of this waste into the city sewer. Total
zinc was not to. exceed 0.10 mg/1 and total chromium was
not to exceed 1.0 mg/1. These were the effluent limits
prescribed by Holley Carburetor in their bid
specifications. Whether conventional "lime and settle"
would meet these effluent limitations was questionable,
as shown by solubility curves for zinc and chromium
hydroxides in Figure No. 2.
The amphoteric properties of metal hydroxides
frequently make the results of the "lime and settle"
approach questionable. An operating pH ideally suited
for good removal of one metal causes another metal to go
•Murray C. Scott
Permutit Company
Paramus, NJ
1
1
Cleaner
A 2
T Rlnte
Rime
4
Deoxldlzer
5
Rinse
6
Out
7
Out
8
Chromate
15
HotRlnie
14
Rime |
13 I
Rinse f
12
Deburrlng
(Chemical)
11
Rinse
10
Phosphate
9
Rinse
»
1
I
To Treatment System
Fig. 1—Automatic line.
TABLE I
PROCESS
Zinc
CYCLES
Dichromaie Deoxidize
Ca
Mg
Na
K
Fe
Mn
At
Cr
Zn
Ni
Cu
Pb
Alk
Cl
SO4
SiO:
P
10 mg/l
4
50
3
1. 4
0.02
6
81
71
0.05
O.IO
O.IO
10
9
40
II.3
65
8 mg/I.
3
39
3
1. 7
0.03
13
46
42
0.05
O.I2
O.IO
12
5
IS
II.3
58
A luminum
Chromate
9 mg/l
3
37
3
I.I
O.IO
4
57
34
0.05
0.07
O.IO
12
6
37
1 0.7
38
106
-------
100
r 10
5
o
8
0.1
I
•
-
.
-
:
<
Fe3
i
4
i
\
\
•
\
t
\
X
\
Cr\
\
J
\
•
\
\
X
\
icu
1
i
i
I
i
\
\
i
\
\
A
i
\
\
\
\
\
a
*
i
\ «
i
\
\
\
\MI
i
/\
i
i
/
'
'
Cd
|
#"
^
li
\
\ \
\ \
\ !
\
/
1
1
/
^
\ t
\v
\\
"
/
;
-
•
5678
pH UNITS
9 10 11 12
Fig. 2
into solution. The solubility curves shown in Figure No. 2
suggest that the pH best suited for removal of zinc is
about 10.0. At this pH (10.0) chromium has a solubility of
about 5.0 nig/1, well above the maximum limit specified
for this meal. The relationship of the solubilities of
chromium and zinc shown in Figure No. 2 are used only
to illustrate potential problems that might occur. These
solubilities will vary with composition of the waste, but,
the amphoteric properties of the precipitated metal
hydroxides are forever present. However, if the heavy
metals could be precipitated as sulfides, a mixture of
metals would not be competing for optimum pH values.
Comparison of the solubilities of various metal
hydroxides and metal sulfides is shown in Figure No. 3.
Not only are the metal sulfides not amphoteric, their
solubilities are theoretically orders of magnitude below
the metal hydroxides and decrease further with
increasing pH.
THE SULFEX™ PROCESS
The Sulfex process uses an insoluble salt as the source
of the sulfide ion. Selection of the salt is not random. The
solubility of the insoluble salt must be greater than the
solubility of the heavy metal sulfide to be precipitated. As
indicated in Table No. 2, ferrous sulfide is more soluble
than the heavy metal sulfides that would be precipitated
from metal finishing waste streams, so the Sulfex process
uses ferrous sulfide as the source of sulfide ions.
Solubility products are taken from Nth edition of
Lange's Handbook of Chemistry.
The iron sulfide works best when it is a freshly
prepared slurry. For practical reasons, pulverized iron
2 3 4 5 6 7 8 9 10 11 12 13
Fig. 3—Solubilities of Metal Hydroxide* and Sulfide*.
TABLE II
SOLUBILITY PRODUCTS
Iron
Zinc
Cadmium
Nickel
Copper
Lead
Mercury
Silver
Hydroxide
8.0 X IO'1*
1.2 X 10"
2.5 X 10 u
10 X 10 "
2.2 X 10 •Nl
8.0 X I0':"
3.0 X I0':"
2.0 X 10"
Sulfide
6.3 X 10 "
1.6 X 10 4
8.0 X 10 '
3.2 X 10 *
6.3 X 10 *
1.2 X 10 '
1.6 X 10
6.3 X 10 «'
sulfide is not used. Since only the surface of the large
particle is useful, much of the iron sulfide particle would
be wasted. However, freshly precipitated iron sulfide has
a great deal of reactive surface. Quantities of iron sulfide
required to adequately remove metals from waste
streams will vary from 1.2 times stoichiometric to 3.0
times stoichiometric.
107
-------
Characteristics of the SulfexIN process, when properly
applied, offer a high degree of flexibility. Because of the
low solubility of iron sulfide, the sulfide ion
concentration is constantly maintained at about 0.02
ppb. Yet sufficient sulfide is available to accommodate
wide variations in influent metal concentrations because
the sludge blanket in the clarifier contains a large
quantity of active iron sulfide. There is the additional
asset of being able to reduce and remove hexavalent
chromium in one step. The chemistry of the Sulfex
process may be illustrated by two equations:
(1) Cu(OH): + FeS - CuS + Fe (OH)2
(2) Na:CrO4 + FeS + 4H2O -
Cr(OH), + Fe(OH)3 + 2NaOH + S
Because of the low concentration of sulfide ion, soluble
sulfide complexes do not form with mercury, tin or silver
as shown in the following equations:
HgS + S= - HgS=2
SnS2 + S= - SnS3=
Ag + S= - AgS~
WASTE TREATMENT SYSTEM
The waste treatment system is designed to handle a
maximum flow of 35 gpm. The operating day is 16 hours.
A schematic of the system is shown in Figure No. 4. The
treatment consists of neutralization, precipitation,
clarification, filtration and sludge dewatering.
All rinse water comes into a two-compartment basin.
The first compartment has a retention time of 105
minutes and the second compartment which normally
operates with an average depth of 3 ft. has a detention
time of about 80 minutes. The second compartment is
operated at a low level so that it may accommodate filter
backwash. These two holding compartments help
equalize the waste but their primary function is to permit
neutralization to a pH of about 8.5. Neutralization is
done in two steps by the addition of lime which is
controlled in both steps by pH sensing devices. The lime
metering pump in the first step operates on-off. In the
second step the lime metering pump has electronic stroke
IIMI Ire* MtMtlc flow M«I«I
AJ^
*•' V- ,_..,-\,-c-
pH VS SHIFT NUUSII
fFFUIIKT
Fig. 5—Average pH Value of Raw Influent, Neutralization Stage I and II,
and Preclpltator Effluent as a Function of Time.
adjustment which is controlled by degree of deviation
from the pH set point. Figure No. 5 shows comparative
pH data for the raw waste, 1st stage neutralization, 2nd
stage neutralization, and treatment plant effluent. The
pH of the precipitator influent was closely controlled,
ranging between a high of 9.0 and a low of 8.3; however,
after the system was stabilized the pH was usually
between 8.3 and 8.7. (The reduction of hexavalent
chromium in the clarifier (precipitator) raised the pH and
produced effluent pH values generally between 8.4 and
9.6).
Neutralized waste is then pumped to the clarifier where
an iron sulfide slurry and a polymer are added. The rate
of addition is proportional to influent flow. Jar tests are
made twice each shift to determine the iron sulfide and
polymer requirement. Timers on the panel board are then
adjusted to change the cycle of the chemical feed pumps.
The stroke of the pumps may also be changed, if desired,
giving further flexibility to control of the chemical
feeders.
The clarifier is a sludge blanket type, as illustrated in
Figure No. 6. A slowly rotating mixer beneath the curtain
baffle promotes floe formation. The floe mixture passes
beneath the baffle into a section where the rise rate
diminishes as the top of the unit is approached. This
produces a blanket with a relatively sharp line of
Fig. 4
L,
Tube Settlers
A ».
\ Sludge -
Mixing Zone Y Blanket-_
1
Outlet
Sludge
Concentrator
Blow-off
Fig. 6
108
-------
coNcwnunoN or raaaut Minn n IHIFT maun
•HUT NUHIIII
Fig. 7—Effect of Variable Ferrous Sulflde Requirement on the Reverse
Ferrous Sulflde Capacity of the Sludge Blanket as a Function of Time.
Note: X's are points where no jar test was made.
demarcation between the top of the blanket and the clear
water above the blanket. This blanket of suspended
solids, which will range in concentration from 5000 mg/I
to 15,000 mg/1, may consist of as much as 50% active iron
sulflde. It is this reservoir of iron sulfide which allows the
system to accommodate wide variations of influent metal
concentrations with no change in the effluent quality.
To illustrate the effect of the iron sulflde reservoir in
the sludge blanket, we ran jar tests on grab samples taken
from the second neutralization basin to determine the
amount of sulflde required. The yellow color of the
chromate in the sample was used as an indicator. Source
of the iron sulflde for this test was slurry taken from the
chemical feed tank. When sufficient iron sulflde slurry
has been added to react with all the metals and the
hexavalent chromium in the sample, the yellow color
disappears. The required iron sulflde dosage indicated by
the jar test and the amount of iron sulflde being
introduced by the chemical feed system at that time were
noted and plotted on the graph shown in Figure No. 7.
Those areas with diagonal lines represent times when
the actual feed of iron sulflde exceeded the demand, so
active iron sulflde was accumulating in the sludge
blanket. The dotted areas represent times when the actual
demand from iron sulflde exceeded the feed rate, so
active iron sulflde from the sludge blanket was being
consumed. Total detention time of iron sulflde in the
sludge blanket is about 19 hrs.
The amount of active iron sulflde in the sludge blanket
A
\
VA > •-, x>-. /
f^\r \ i v
^ " \.. r'
can be controlled by adjusting the rate of feed of the iron
sulfide slurry; however, excessive feed rates will increase
chemical operating costs. For this reason, we were
interested in stoichiometric iron sulfide requirements.
The waste was analyzed for metals and then the
stoichiometric sulflde requirement was obtained by
calculation. A comparison of stoichiometric sulflde
requirement and the sulfide requirement indicated by jar
testing is shown in Figure No. 8. The jar test sulfide
demand varied from 200% to 500% of the theoretical,
averaging about 3.5 times stoichiometric. With more
operating experience, closer control is expected to reduce
the iron sulflde consumption.
The clarifier has a sludge concentrator which is blown
off automatically, based on influent flow to the clarifier.
Since the amount of blowoff required is a function of
both the hydraulic load and the suspended solids load,
the blowoff rate is further controlled by adjusting a timer
which determines the length of time the blowoff valve is
open. This is estimated by collecting a sample from the
unit to determine the height of the sludge blanket in the
tube settlers. Two sampling points, one within the tube
settlers and one six inches below the tube settlers, permits
the operator to determine whether the blanket is too high
or too low.
The blowoff is collected in a sump and then pumped
through a filter press for dewatering. A polypropylene
filter cloth is used. No precoat or body feed is required.
Operation is at constant pump drive speed until the
pressure builds up to 50 Ibs. At this pressure, the resulting
cake breaks away cleanly from the cloth. Down time is
about 10-15 minutes. Operating time is about 10-14
hours. The unit holds slightly over 5 cu. ft. Dewatered
cake is disposed at a local landfill.
The feed to the press contained from 14,000 mg/1 to
24,000 mg/1 suspended solids. Effluent from the press
contained about 3 mg/1 suspended solids at the beginning
of the run and 22 mg/1 at breakthrough (at end of run).
Filter cake contained about 25% solids. On a total dry
weight basis, the percentages of metals in the filter cake
are shown in Table No. 3
The Sulfex process produces more sludge than a
conventional "lime and settle" process, because a mole of
insoluble ferrous hydroxide is produced for each mole of
heavy metal sulfide formed. The excess iron sulfide in the
clarifier sludge blanket also adds to sludge volume. This
must be taken into consideration and adequate sludge
disposal included as part of the overall design of the
Sulfex treatment system. For example:
When designing a conventional rinse water waste
Fig. 8—Theoretical Ferrous Sultide Requirement Compared with Jar Test
Requirement as a function of Time.
Note: X'* are points where no Jar test was made.
TABLE III
Cr
Fe
Cu
Zn
Total Solids
3.3% to 4.5%
26.9% to 33.0%
<0.l%
3.7% to 4.1%
23.4% to 29.3%
109
-------
treatment system, the waste is usually neutralized before
clarification. The addition of iron sulfide to the clarifier
converts this treatment system to the Sulfex'N process.
This method of applying the Sulfex process results in a
substantial increase in sludge production (on the order of
2.8 times) over straight lime treatment. It can only be
justified where total metal concentrations are very low, or
where there is inadequate space to permit a Sulfex
polishing system.
A Sulfex polishing system uses a second clarifier. Iron
sulfide and a polymer are added to this clarifier.
Chemical requirements are quite low, since only residual
metals from the hydroxide process need be treated. In
applications of this type, the amount of additional sludge
produced by the Sulfex process usually will amount to
only 1% to 2% of the total sludge produced by the entire
treatment system.
Supernatant from the clarifier is then pumped to a dual
media, anthracite-sand, filter which is equipped with an
air scour to insure good cleaning during the backwash
procedure. Prudence, sound engineering, and
requirement of a performance guarantee make filtration
mandatory, but excellent quality is possible without
filtration, as illustrated in Table No. 4.
Metal
Zn
Fe
Cu
Cr (Total)
Cr'*
Total Suspended
Solids
TABLE IV
Clarifier Effluent
mg/l
0. 1 to 0.5
0.3 to 4.0
$0.01
0.1 to 1.0
$ 0.05
1.0 to 10
Filtered Effluent
mg/l
$ 0.05
$0.50
$0.01
$0.04
$0.04
$ 0.5 - 1.0
Filtered effluent from the treatment system at Holley
Carburetor routinely produced metal concentrations
lower than detectable by today's accepted analytical
methods. Metal concentrations in the influent and
effluent are shown in Figures No.'s. 9, 10, II, 12, 13.
10&00-
S10JO-
5 tjo-
wi.
a
HKXAVALIMT CHftOMI CONCtNTMTION V» SHOT NUUMM
*"**• MrUKMT
•rnuoa
I i i i t i i 1 i i
o 4» uiuit«iuauiuiUiU4&a
•KmHUHUH
Fig. 10—Average Concentration of Hexavalent Chrome In Raw Influent
and Filter Effluent as a Function of Time.
TOTAL CHMOm COMCtMTHATKM Vt tWT HUHHR
_AJ
Fig. 11—Average Concentration of Total Chromium In Raw Influent and
Filter Effluent as a Function of Time.
TOT«I me coxcnnuTiai n wm Minn*
no iu mo
Fig. 12—Average Concentration of Total Zinc In Raw Influent and Filter
Effluent as a Function of Time.
tOTAl MOM CONCUTUT10N
.DinUIMT
• ,
•-
U U U IU
IU M> *U
-------
CHEMICAL OPERATING COSTS
Detailed data was collected over a period of 38 shifts
(19 days). This included the startup period when all
equipment was checked out and plant personnel were
being trained. About 22 shifts (11 days) were required to
reach a steady state where operating conditions were
considered normal. For this reason only, data collected
during the last 16 shifts (8 days) were used for calculating
chemical operating costs. During this period, the flow
averaged 26 gpm. Metal concentration averaged 34 mg/1
Cr*6 and 34.7 mg/1 Zn. The pH ranged between 5.2 and
6.5
Unit cost for chemicals were as follows:
Ferrous Sulfate 6.75e/lb
Sodium Sulfhydrate 26.5e/lb
Lime 4.65
-------
Comparing the chemical costs for treatment of this
waste by conventional methods with chemical costs for
treatment by the Sulfex process is difficult, but the
following data is a reasonable estimate:
For Chromium
For Zinc
For Sludge
Disposal
total
TABLE
Conventional
S6.4I kg
0.17/kg
1.16
57. 74
V
Primary
Sulfex
$6.38, kg
5.05, kg
2.32
$13.75
Polishing
Sulfex
$6.39/kg
• 17/kg
1.88
S8.44
With this particular waste, a portion of the sludge
comes from precipitation of phosphate. Unfortunately,
we did not collect detailed analytical data on phosphate
concentrations because removal of phosphate was not
required. The original analytical data showed a low
phosphate concentration of 38 mg/1 as P and a high of 65
mg/las P. The low concentration was used for estimating
the sludge produced by phosphate precipitation and the
value was included in the assessment of comparative
sludge disposal costs.
Increased chemical usage and increased sludge is the
premium paid for primary Sulfex treatment where the
FeS is added to the same clarifier that would be used for
conventional hydroxide precipitation. The third column
in Table No. 4 shows costs for chemicals and sludge
disposal for a complete treatment system which includes
polishing by the Sulfex process.
COST ANALYSIS
Operating Costs
The yearly operating cost, excluding depreciation and
licensing fees, for the treatment system at Holley
Carburetor is outlined below. This cost results from
charges incurred by operators, utilities and chemicals.
The estimated yearly operating cost, based on plant
performance to date, is as follows:
1. Operators Salaries:
$10,800 per operator X 2 operators = $21,600
+ fringe benefits at 40% = 8,640
Total Salaries
= $30,240/year
2. Electricity:
203.32 kwh 5 day 52 wk. $0.0191
x X X = $IOIO/year
day
wk.
kwh
3. Water:
4162m1 X$0.053/m'
4. Chemical:
$14.69 2 shifts 260 days
X X = $7639/year
shift day yr.
5. Sludge Handling and Disposal
Cost:
$15 260 days
x = $3900/year
day yr.
Total Operating Cost is therefore:
Salaries
+ Electricity
+ Water
+ Chemicals
+ Sludge Disposal
TOTAL
= $30,240
= 1,010
220
= 7,639
= 3,900
$43,009/year
= $220/year
Capital costs are itemized as follows:
Equipment $92,465
Engineering Costs 17,400
(Consulting, report to
state and design for
underground tanks)
Underground Tanks 48,000
Shipping and Instal-
lation 21,730
Taxes
(on equipment only) 1,089
$180,684
SUMMARY
Precipitation of heavy metals by sulfide will in most
cases permit any plant to economically meet extremely
rigid discharge standards but frequent complaints are
lodged that disposal of sulfide sludges presents a serious
impediment to acceptance of any sulfide process for
heavy metals removal. The complaints are not necessarily
on solid ground.
In almost all cases the waste streams are neutralized
with lime or caustic. This results in the precipitation of
metal hydroxides. The next logical step is to remove these
precipitated metals by coagulation and settling or any
other technique that might be applicable. Sulfide
precipitation, if required, should be applied to residual
soluble metals which represent a very small portion of the
total metals originally present in the waste streams. Is
there any reason why this very small sludge portion
consisting of metal sulfides cannot be disposed in the
same manner as the large portion of metal hydroxides?
The leaching test procedure, described in the Dec. 18,
1978 Federal Register, page 58596, was used to obtain the
following comparative data on a sludge produced by the
Sulfex process and on a sludge produced by the addition
112
-------
of lime. A solution containing 20 mg/1 of each metal was
used for the test. Equal portions of this solution were
treated, one by Sulfex™ and the other by lime. The sludge
produced by each procedure was then subjected to the
leaching test recommended by the EPA. The pH of the
Sulfex mixture was 5.7. The pH of the hydroxide mixture
was 5.8.
The Sulfex mixture gave no odor of HjS nor was there
any evidence of H:S detectable by lead acetate paper.
EXTRACT LEVEL mg/1
Arsenic
Barium
Cadmium
Chromium
(Total)
Lead
Mercury
Selenium
Silver
MAY
Ni
Fe
Zn
Cu
EPA Proposed
Regulation
0.50
10.0
0.10
0.50
0.50
0.02
0.10
0.50
Sulfex
_
—
0.02
<0.05
0.20
—
.
0.02
Hydroxide
,
»
1000
1.5
55
-
0.21
BE CONSIDERED IN FUTURE
3
50
10
35
820
0.36
0.03
>33
< 1
1475
259
These data would suggest that disposal of sulfide
sludges will present no more of a problem than disposal
of hydroxide sludges. Both appear to be material that
should be disposed in a secure landfill.
113
-------
The Development of an Activated Carbon Process
For the Treatment of Chromium (VI)—
Containing Plating Wastewater
C. P. Huang & A. R. Bowers*
INTRODUCTION
Ever since Ostrejko' discovered in 1900 that, when
treated with mineral chloride, vegetable charcoal exhibits
decoloring power 10 times greater than untreated
charcoal, many brands of activated carbon have been
manufactured and used by various industries.2'3 Early
applications of activated carbon were associated mainly
with material production, such as sugar refining, oil and
drug purification. Use of activated carbon for water
treatment in the United States was first reported in 1930,
for the elimination of taste and odor.4 Due, in part, to this
historical connection, most of the applications of and
research effort on activated carbon in the water and
wastewater industries are oriented toward organics
removal. Research efforts on inorganics removal by
activated carbon, specifically metallic ions, are markedly
limited.
This paper presents some of the most recent
developments concerning applications of activated
carbon for total chromium removal.
Recently, the removal of inorganic pollutants and
heavy metals by activated carbon adsorption has received
considerable attention. Much of this work has been done
in Japan, where heavy metals are a pressing concern.
Kawashima and others reported significant removal of
heavy metals from synthetic wastewaters using activated
charcoal.5 Saito showed that the removal of heavy metals
such as copper, cadmium and ferric iron could be
improved by treating activated carbon with sulfonate.6
Huang and Ostovic found a variety of commercial
activated carbons to effectively adsorb cadmium, Cd(II),
from dilute aqueous solution, largely as a result of charge
development on the carbon surface.7
Use of activated carbon to remove chromium (VI)
from water is a recent endeavor. Toyokichi reported that8
chromates are effectively removed by passing wastewater
containing chromates through a column packed with
platinum black catalyst-impregnated activated carbon.
*C. P. Huang. Associate Professor
A. R. Bowers. Doctoral student
Environmental Engineering Program
University of Delaware, Newark, DE 19711
One kg of activated carbon was mixed with 1 ml platinum
black colloid containing 0.001 mg Pt/1 and 1 g pure
FhSCX. The platinum black catalyst-impregnated
activated carbon (SO 1) was packed in a column, then
wastewater containing 100 ppm of chromate was passed
through the column at 1 m3/hr. The resulting wastewater
contained less than 0.1 ppm of chromate. Similar
research was conducted by Tagashira, et al.,9 who found
that mixing 200 ml fcC^O? solution (534 ppm Cr) with
5 g powder coconut shell charcoal (100-200 mesh 15%,
200-325 mesh 15% and < 325 mesh 70%) and heating in an
autoclave at 200° C for 30 minutes can reduce the Cr(VI)
concentration to 0.01 ppm.
Huang and Wu'° studied the removal of chromium(VI)
by calcinated charcoal and found that removal was most
significant at low pH and low initial Cr(VI)
concentration, they also postulated that HCrO4" ions are
the major species being removed.
Seto and Tsuda" reported that by mixing a 50-ml
NazCrO* (10%) solution, with 5 g activated carbon in a
flask for 2 hrs at 25° C, the CrOs adsorption by the
activated carbon was 38.7% and 3.3%, respectively, when
the pH was 3 and 7.
By heating lignite with 14% HNOs acid for 13 minutes,
Nagasaki12 demonstrated that chromic acid ions were
effectively removed. By passing a wastewater containing
chromic acid (100 ppm), with pH being adjusted to equal
to or lower than that of chromic acid, through an
activated carbon column for 100 hrs, Nagasaki and
Terada13 reported that the effluent contained neither
Cr(VI) nor Cr(III). After treating 1350 1 of wastewater,
the effluent pH went up to 7 and contained 0.5 ppm
Cr(VI). Ten liters of 25% HC1 solution were then passed
through the column to regenerate the column by
dissolving the reduced Cr(III). The column was reused
for another 100 hrs without breakthrough.
A Dutch process for reducing Cr+6 to Cr*3 with
activated carbon was proposed by Roersma, et al.14 An
EPA-supported work conducted by Landrigan and
Hallowell also demonstrated that activated carbon can
be used by many small plating plants to remove their
chromium to relieve the burden on municipal sewage
systems.
Yoshida, el a/.,"1 studied the adsorption of Cr(VI) and
Cr(III) onto activated carbon as a function of pH and the
114
-------
amount of total Cr and Cr (VI) eluted from activated
carbon at pH 4 - 6.5. They reported that Cr(VI) is readily
adsorbed on activated carbon as anionic species such as
HCrO4~ and CrtV2, while Cr*3 ion is scarcely adsorbed
on activated carbon. They also observed that in acidic
solution, Cr(VI) is easily reduced to Cr(III) in the
presence of activated carbon. The adsorbed Cr(VI)
species was elutable with NaOH(X).I N) or with 1 N HC1
solution.
Huang and Wu17 studied the effect of pH on Cr(VI)
and Cr(III) adsorption by Filtrasorb 400 activated
carbon.
It is evident that Cr(VI) can be readily reduced to
Cr(III) at acidic condition and in the presence of
activated carbon. Kim18 reported that the reduction
reaction can be suppressed by adjusting the proton
concentration (i.e., H ions) to become equal to that of
the hexavalent chromate, or to maintain a Cr(VI) system
predominated by HCr(V species. Although a similar
statement has been made by Nagasaki and Terada,13 no
such finding was observed in a recent and more detailed
study conducted by Huang and Bowers."
INTERACTIONS OF CR(VI)
WITH ACTIVATED CARBON
The removal of Cr(VI) from solution occurs through
several steps of interfacial reactions: 1) the direct
adsorption of Cr(Vl) onto the carbon surface; 2) the
reduction of Cr(VI) species to Cr(III) by carbon on the
surface; and 3) adsorption of the Cr(lII) species
produced, which occurs to a much lesser extent than the
adsorption of the Cr(VI) species. The rate of each
reaction depends on the following mechanisms: a) the
transport of Cr(VI) anions, HCrCV, by molecular or
eddy diffusion, toward the carbon surface; b) chemical
reactions, reduction and/ or adsorption, which take place
on the external carbon surface; c) desorption and back
transport of the Cr(VI) and Cr(III) species from the
external surface into the bulk phase; d) inner transport of
the Cr(VI) and Cr(III) species into the internal surfaces
bounding the micropores and capillaries of the carbon; e)
chemical reactions, reduction and/or adsorption, taking
place at the internal surfaces; and i) back transport of the
Cr(VI) and Cr(HI) species across the internal surface and
the external interface into the bulk phase.
Batch Experimental Cr(VI) Adsorption
Huang and Bowers20 have conducted batch
experiments on the kinetics of Cr(VI) removal of
Filtrasorb 400 activated carbon. They found that
reduction and adsorption occurred simultaneously and
the kinetic equations were:
(D
dCr(Vl) 2.4[HCr04'][qG[H'l
~~dt red l.2 + 4.8XI04[Cr(lll)] + 2.4XIO'G[H<][Cr(VI)]
which is the rate of Cr(VI) reduction and:
(
dCr(VI)
dt
) =2.9XIO-'[HT-'[C][Cr(VI)] t,__L
ads l r«
which is the rate of Cr(VI) adsorption:
where the determining variables are as follows:
[C] = concentration of Filtrasorb 400 in the reactor
(g/0
[HCrOr] = concentration of bichromate (M)
[Cr(VI)] = concentration of total Cr(VI) species (M)
[Cr(HI)] = concentration of soluble Cr*3 cations (M)
[H+] = concentration of protons in solution (M)
G = average velocity gradients in the reactor (sec"1)
F = the instantaneous adsorption density of Cr(VI) on the
carbon surface (/u mole/g)
Ft = the adsorption density of Cr(VI) at equilibrium with
the surface and liquid phases.
Batch experiments also showed that the maximum
Cr(VI) adsorptive capacity of the carbon occurred at pH
2.5 and decreased rapidly between pH 2.5 and 7.1,
primarily due to the decreasing electrostatic attraction
between the postively charged carbon surface and the
anionic Cr(VI) species in solution. The Cr( VI) adsorptive
capacity decreased at pH < 2.5 due to the rapid reduction
of the Cr(VI) species and the subsequent dominance of
the cationic Cr(III) species at low pH.
Based upon these reaction Equations (1 and la), it is
possible to eliminate Cr(III) production to achieve total
Cr(VI) removal with a batch reactor.
Experiments with Packed Columns
Loosely packed carbon columns were run to determine
the importance of the various operational parameters in
maintaining an efficient and effective system for removal
of Cr(VI) and to minimize the amount of Cr(III)
produced.
The effects of carbon bed depth, influent Cr(VI)
concentration, and pH on the removal efficiency were
studied. Pre-washing of the carbon before contact with
Cr(VI) was also investigated.
The influence of bed size on the removal efficiency is
indicated in Figure 1 (a through d) for 10, 30 and 50 gram
carbon beds, all receiving a constant influent of 2
gal/min/ft2 or 44 ml/min, at pH 2.50, 10"3 M Na2CrO4
(52 ppm as Cr) and 0.1 M NaCl for ionic strength. The
inability of the carbon to remove all of the Cr(VI) over
the first few bed volumes, Figure 1 (a), is due to the high
initial pH observed, primarily due to the amount of H*
ions needed to hydrolyze the carbon surface. Since there
is no Cr(VI) present after 100 bed volumes for 30 or 50
gram beds, Figure I (c), indicates that adsorption of the
trivalent species does not occur and may be neglected.
The influent Cr(VI) concentration was varied from I X
10~4 M to 5 X 10'3 M NazCrO*, 5.2 to 260 ppm as Cr, while
the carbon bed size, influent pH, and flow rate remained
constant, 50 g, 150, and 2 gal/min/ft2, respectively. The
results of these experiments are shown in Figure 2 (a
through d). Figure 2 (a) shows a retardant effect of
increased Cr(VI) concentration on the time required for
115
-------
• Blank -0- Cr(Bl)
Q lOg I--400
m SOg F - 400
o SOg F - 400
(a)
200 400 600
No. Bid Volumn
200 4OO 6OO
No. Btd Volumii
• 0 - Cr (JEM
0 S »IOTS M
0 I « Itr8 M
100 200 300
No. Bid Volumii
100 200 300
No. Bed Volumii
900
400
v
•
\ 300
jt
t-, zoo
too
20O 4OO 6OO
No. Bid Volumll
ZOO 4OO 600
No. Bid Volumll
Fig. 1 —The effect of carbon bed size on: a. pH, b. residual Cr(VI), c. Cr(lll)
produced, and d. the Cr(VI) adsorption density.
(e)
aoo
eoo
too
zoo
(00 200 300
No. Bid Volumn
100 200 300
No. Bid Volumn
Fig. 2—The effect of Increasing Cr(VI) concentration In the Influent to a
constant bed size (SOg) on: a. pH, b. residual Cr(VI), c. Cr(lll) produced,
and d. the Cr(VI) adsorption density.
the pH of the column to equilibrate as the surface
hydrolysis reactions go to completion. This is due to the
increased demand imposed on the H* concentration as
the influent Cr(VI) concentration is increased and more
Cr(III) is subsequently produced, Figure 2 (c), and more
Cr(VI) is adsorbed, Figure 2 (d).
The removal of Cr(VI) is incomplete for the initial bed
volumes, Figure 2 (b), due to the high pH which is
maintained for the first 100 bed volumes as a result of the
If demand for the hydrolysis reactions. The complete
removal of 5 X 10"3 M Cr(VI) was never achieved during
the entire experiment, since the pH remained high
(greater than 4 over the entire 300 bed volumes). The n
concentration was insufficient to obtain complete
removal. Also, the results of Figure 2 (c) show that
Cr(III) will still be produced when the influent Cr(VI) to
H* ratio is greater than one (1.58 for 5 X10"3 M Cr(VI) to
pH 2.50). The 1:1 ratio only applies generally, when the
Cr(VI) concentration is less than 1X 10"4 M or when a 1:1
ratio implies the pH is greater than 4.0, which is not a
strong reducing condition regardless of the Cr(VI)
concentration. Equation (la) shows the reduction rate to
depend on the first power of the HT concentration. This
finding did not agree with what was reported by Kim and
Zoltek,18 who claimed a 1:1 total Cr(VI) to Bf for
minimum reduction and maximum adsorption reactions.
To eliminate the initial Cr(VI) removal deficiency and
smooth out the pH in the system, the carbon must be pre-
washed with an acidic solution before contact with
Cr(VI). It is not recommended that a strong acid solution
be used for this wash cycle, since strong acids are
corrosive to the carbon and may result in a degree of
hydrolysis which overshoots the equilibrium that can be
obtained by the H* concentration in the subsequent
wastewater influent. Therefore, the carbon must be
hydrolyzed by a wash solution which closely
approximates the pH of the influent to be treated. In a
column configuration, the wash cycle may be
accomplished in approximately 150 bed volumes or less,
by a pH of 2.50 or less, while at pH 3.00 or greater the
wash cycle requires too much time and becomes a
cumbersome operation. In this case it may be more
convenient to eliminate the concentration gradients
which occur in a packed column and hydrolyze the
carbon granules by titrating them with acid in a well-
mixed reactor until an equilibrium pH is obtained, before
placing the carbon into the column.
The results of pre-washing with 150 bed volumes of pH
2.50, 0.1 M NaCl washwater before contacting the
carbon with Cr(VI) are shown in Figures 3 and 4 for 50
grams of carbon, 5 X 10"" M and 1 X 10"3 M Na2GrC>4,
respectively, in the influent. The pH is observed to be
116
-------
_ 4
5 s
w
u
o
$ i I0"4 M NotCr04 ; O.I M Nod
SO gromt Carbon - priwoshid- pH'2.3
> pH o Cr(m)
• Cr(in)
3 PH
290
200
ISO E
100
1.0
400
No. Bid Volumti
600
Fig. 3—The effluent characteristics of a 5 x 10'' M Na,CrO, (26 ppm Cr(VI))
wastewater after treatment with a pre-washed packed column.
much smoother over the course of operation and no
Cr(VI) was detected in the effluent for 600 bed volumes.
The production of Cr(III) was also consistent and
increased linearly as the adsorption equilibrium and the
progressive increase in Cr(VI) concentration propagated
up the column.
Operation of Packed Column
Reduction of the Cr(VI) species cannot be eliminated
from a packed carbon column, but a packed column is
the most economical and simplest treatment scheme to
operate. Therefore, if a separate carbon system can be
devised to remove the Cr(III) produced, packed carbon
columns would be an efficient, simple, economical and
environmentally compatable treatment process for the
removal of hexavalent chromium species from
wastewater.
Column operation is sensitive to the pH in the
wastewater influent stream since there is a stoichiometric
requirement of 1 mole of H+ per mole Cr(VI) adsorbed
and 4 moles of H* per mole Cr(VI) reduced. In order to
completely remove all of the Cr(VI) from solution, a 1:1
molar ratio of H* to Cr(VI) would be the absolute
minimum ration of H+:Cr(VI), if Cr(VI) was removed
exclusively by adsorption. In fact, an excess of H* is
required to satisfy the stoichiometric demand of H* for
reduction and to prevent the decreased H* concentration
in the latter portions of the column from limiting the
removal rates and the Cr(VI) adsorptive capacity of the
carbon.
For a case study, treating 10,000 gal of wastewater per
day with I X 10~3 M Cr(VI) (or 52 ppm Cr), the maximum
pH in the influent would be 3.0. However, an excess of H+
is desired and the maximum Cr(VI) adsorptive capacity
of the carbon occurs at pH 2.50 (70 mg Cr(VI)/g). Bench
scale experiments have also indicated excellent Cr(VI)
removal performance at this pH value.20 Therefore, pH
2.50 appears to be the optimum condition for complete
removal of Cr(VI) by adsorption and reduction.
The surface loading rate of the carbon columns in this
study was 2 gal/ min/ft2. Therefore, at a wastewater flow
rate of 10,000 gal/day operating 8 hr/day, the column
would require 10.4 ft of surface area or be 3.64 ft in
diameter.
'o
I i 10 M NOjCrO,, ; 0.1 M NoCI
30 gromi Carbon- ft »«oilitd-pH • 2.3
i pH O Crlm)
• CrOQ)
O.S
ZOO
4OO
No. B«d Volumls
600
Fig. 4—The effluent characteristics of a 1 * 10'' M Na,CrO,(52 ppm Cr(VI)
wastewaler after treatment with » pre-washed column.
The depth of the column can be estimated from
experimental data. Table I shows the experimental bed
size and the number of influent bed volumes passed
through each column before breakthrough occurred.
A log-log plot of bed volumes vs bed depth is shown in
Figure 5. The number of bed volumes may then be
written as a function of bed depth or:
log (BVh) = 0.92 log (dh) + 2.94 (2)
where BVh = number of bed volumes to breakthrough
dh = carbon bed depth (ft)
The depth of the bed can be evaluated by choosing the
desired time interval between regenerations, which
implies:
where: Q = wastewater flow rate (gal/day)
t = time interval between regenerations (days of
actual system operation)
S. A. = column surface area perpendicular to the
flow (ft2)
Q, t and S. A. should all be known, from which dh can
be derived by solving Equation (2). By assuming 10,000
gal/day with regeneration cycles once a month (22 days
of actual operation), dh = 2.4 ft. Therefore, a 4ft diameter
by 3 ft depth carbon bed would be a conservative design
TABLE 1
Column depth versus number of bed volumes
to Cr(VI) breakthrough'
bed size
(grams)
10
30
50
bed depth
(ft)
0.70
0.42
O.I4
' flow rate = 2 gal/min/fr; pH = 2.5;
no. of bed volumes
to breakthrough
1 25
400
600
total Cr(VI) = I X IO" M
117
-------
2.8
o
Ol
w
.0
o
2.4
2.0
Inflow = 2 gal/min/ft
pH =2.5
I x I0"3 M Nc
0.92
100
0.2 0.6
-log [bed depth (ft)]
1.0
Fig. 5—Bed volume to breakthrough at a function of carbon bed depth lor
1 * 10-' M Na,CrO. at pH 2.50.
and require 1,082 Ibs of carbon @ 61c/lb. Thus,
regenerating once a month at a 2% carbon loss means the
operating cost for carbon for the column would be
O.OU/gal.
The initial column must be followed by a Cr(IIl)
treatment system capable of treating 10,000 gal/day at
2.0 to 3.0 X 10"4 M Cr(III) (10 ~ 15 ppm).
It is also relevant to compare the cost of using activated
carbon for Cr(Vl) reduction to the cost of conventional
reduction with sulfur dioxide (SO:). The following unit
material costs can be attributed to each:
Filtrasorb 400 costs 61
-------
100
I—I
Combined
Caustic
Thermal
Process
234 1234 1234
Adsorption Cycles
Fig. 7—A comparison of regeneration techniques alter 4 adsorption cycles
and successive regeneration cycles.
most effective, while 1 % NaOH is next best, and drying in
air at 103° C or 550° C appear to create little readsorp-
tion capacity. A comparison of the caustic, thermal (950°
C in CO:) and combined caustic-thermal regeneration
techniques over several regeneration cycles is shown in
Figure 7. Here the combined caustic-thermal technique
acquires an advantage over the thermal regeneration
alone, and the thermal regeneration approaches the same
readsorptive capacity as caustic regeneration, as
subsequent regeneration cycles are performed.
Loss of Carbon
The loss of original carbon due to various physical-
chemical reactions is shown in Table 2.
The average loss of 0.17% carbon by weight during the
first adsorption cycle, and another 0.06% loss per
additional adsorption cycle, was due mostly to carbon
ash. A 1.5% loss of carbon was found when it was treated
with 1% NaOH solution. Heating the used carbon in air
at 550° C caused the greatest loss of carbon, apparently
due to combustion. Thermal activation at 950° C in a
COj atmosphere gave 5% loss of carbon.
Disadvantages of Thermal Regeneration
Even though the thermal regeneration technique
appears to be more effective in restoring the Cr(Vl)
adsorptive capacity, the disadvantages of a thermal
regeneration system are significant.
TABLE 2
AVerage loss of carbon
during batch adsorption and regeneration cycles
Type of Operation
First adsorption cycle
Further adsorption cycles
Caustic regeneration cycle
(\ri NaOH)
Thermal regeneration cycle
at 550° C in air
Thermal regeneration cycle
at 950° C in CO:
Average Lux* of
Carbon per Cycle,
f-c by Weight
0.17
0.06
1.50
7.40
5.00
I. Thermal regeneration at 950° C in CO: results in a 5%
loss of carbon, which translates into significant costs
to supply the lost carbon.
2. The costs of building and operating a multiple hearth
or fluidized bed furnace at 950° C for regeneration are
prohibitive, except on a very large scale.
3. The resulting air pollutants, chrome carbonyl or other
organo-chromium compounds, which are formed at
high temperatures would require a great deal of
additional study and undoubtedly require stringent
controls which could be economically and
technologically unfeasible.
Therefore, thermal techniques for regeneration of
carbons laden with chromium cannot be an
environmentally compatible or economically sound
procedure.
Caustic Desorption of Adsorbed Chromium
The desorption of chromium from the carbon surface
by treatment with caustic solution can be measured
directly from chromium analysis of the wastewater
treated and the regenerant solution used. Figure 7 shows
the percent of chromium desorbed from the carbon
surface by various NaOH solutions after successive 24
hour regeneration contact periods with the carbon. Ten
grams of carbon were used, which was brought close to
equilibrium in a packed column after 1300 bed volumes
of influent, I X 10"' M NajCrOi, pH 2.50 and O.I M
NaCl, which is equivalent to an adsorption density of ca
940 jum/g (5 mg Cr/g). The carbon was then regenerated
in 500 ml of NaOH solution at the indicated strength.
From Figure 8, chromium is seen to be more effectively
desorbed from the carbon surface as the strength of the
caustic solution is increased, but the weaker solutions
approach the efficiency of the stronger solutions as the
number of regeneration cycles are increased. Therefore,
the concentration ratio between chromium in the bulk
solution and on the carbon surface increases with the
caustic strength. Figure 9 shows the Cr(VI)
concentrations reached in the bulk solution for the
various caustic solutions during the regeneration cycles.
119
-------
100
80
•o
o
•o
S 60
- 40
20
1.0 M NoOH
M NoOH
0123
No. Of Regenerations
Fig. 8—Percent desorption of chromium from the carbon surface by
caustic solution.
10 20 10 20 10 20
Fig. 9—The concentration of Cr(VI) desorbed In caustic solution as a
function of time.
Notice that close to 100% regeneration is achieved by 1.0
M NaOH after 1 cycle for 500 and 2SO ml volumes of
caustic solution, but the concentration of Cr(VI) is
doubled for the solution of lesser volume.
The primary goal of any waste treatment system is to
concentrate large volumes of wastewater into a small
volume of waste, which is easy to handle and dispose of.
Therefore, the purpose of regeneration is not only to
remove the adsorbed chromium for the surface, but to
concentrate that chromium into the smallest regenerate
stream possible. Figure 10 shows the maximum
concentration of Cr(VI) that can be collected in the
regenerant at various concentrations of caustic solution.
Acidic Desorption of Cr(VI)
Regeneration of the exhausted carbon with strong acid
solution appears attractive in an economical sense,
because acid is generally less expensive than caustic.
Figure 11 shows the reduction and desorption of
adsorbed Cr(Vl) from the carbon surface in 0.1 M HC1
solution. The desorption in the acid solution is much
slower than that observed in the caustic regenerate
solutions, however, stronger acid solutions may be used
to speed up the reaction and increase the extent of
desorption.
In contrast to caustic regeneration, strong acid
regeneration can only strip off Cr(IIl) from the carbon
surface. This provides an option for the regeneration of
Cr(III)-laden activated carbon.
REMOVAL OF Cr (III)
As indicated previously, Cr(III) production is difficult
to prevent in column operations. If the process of packed
200O
> 1000
h.
u
NaOH %
Fig. 10—Maximum Cr(VI) concentration obtainable In regenerant
solutions of various caustic strength.
I0 grams F- 400
500 ml O.I M HCI
10
20
30
40
50
60
Reaction Time (hr)
Fig. 11—The desorption of Cr(VI) from the carbon surface In addle
solution as Cr(lll).
120
-------
carbon column for Cr(VI) removal is selected, the
effluent must be treated to remove Cr(III). As indicated
by Huang and Ostovic,7 a different type of carbon is
needed for the removal of cations such as Cr(Ill). Results
of the preliminary tests on the adsorption characteristics
of Cr(III) by various brands of commercial activated
carbon are shown in Table 3.
TABLE 3
Comparative removal by various activated carbons.
Carbon type
Filtrasorb 100
Filtrasorb 200
Filtrasorb 300
Filtrasorb 400
Nuchar WVG
Nuchar WVL
MCB CX 647
Darco HD300
PH
4
4
4
4
4
4
4
4
Cr(lll) removed 124 hrx
IS
9
9
10
10
17
14
7
Original Cr(lll) concentration = 5 X 10
Ionic strength = 0.1 M NaCI
Carbon dosage = 29'I
M CrCli
100
80
6O
40
20
3 45678
PH
Fig. 12—The percent of Cr(lll) by adsorption or precipitation under
various conditions.
1. theoretical Cr(OH), precipitation expected without the presence of
carbon
2. actual Cr(OH) precipitation observed without the presence of carbon
3. 2 g/l N-VWL '
4. 4 g/l N-VWL
5. 6 g/l N-VWL
The percentage of Cr(III) removal appears rather small
under this particular set of experimental conditions.
However, it is possible to identify the rather promising
carbon types: Nuchar WVL, Filtrasorb 100 and MCB
CX647.
To improve the percentage of removal, it is important
to adjust the pH values to > 4, or to use enough activated
carbon (Figure 12). A more thorough investigation on
the application of activated carbon for Cr(lll) removal is
now being undertaken in the authors' laboratory.
ACKNOWLEDGEMENT
This work was supported by an Environmental
Protection Agency Grant, No. R804656-OIOI. However,
any opinions, findings, conclusions or recommendations
expressed herein are those of the authors and do not
necessarily reflect the view of the Agency. We would like
to thank Ms. Mary Stinson, our project manager, for her
assistance and suggestions on many occasions during the
course of this research project.
REFERENCES
1. Ostrejko, R., British Patents 14224 (1900); 18040
(1900); German Patent, 136792 (1901) (Ref. 3).
2. Hassler, J. W., "Active Carbon: The Modern
Purifier," New York: Githens-Sohl Co., 1941.
3. Hassler, J. W., "Activated Carbon," New York:
Chemical Publishing Co., 1963.
4. Mantell, C. L., "Carbon and Graphite Handbook,"
Chapter 13, New York, Wiley Interscience, 1968.
5. Kawashimat, et a/., "Treatment of Wastewater Con-
taining Heavy Metal Ions Using Activated Charcoal,
Mitzushou Gijutsu (Japan), 14(4): 379 Chemical
Abstracts 79, 57376, 1973.
6. Saito, I., "Removal of Heavy Metals from Aqueous
Solutions Using Sulfonated Coal and Activated
Carbon," Kogai Shigen Kenkyusho Iho (Japan),
5(2):57-64, 1976.
7. Huang, C. P., F. B. Ostovic, "The Removal of
Cadmium (II) from Dilute Aqueous Solution by
Activated Carbon Adsorption," J. Env. Engr.,
ASCE, 104 (EES), 863-878, 1978.
8. Abe, T., "Purification of Chromate-Containing
Waste Water," Japan. Kokai 740717 (1974) (in
Japanese CA082080475I 2B).
9. Tagashira, Y., H. Takagi, K. Inagaki, and H.
Minoura, "Removal of Chromium Ions from Waste
Waters with Activated Carbons," Japan. Kokai
750820 (1975) (in Japanese CA08410065057C).
10. Huang, C. P., and M. H. Wu, "Chromium Removal
by Carbon Adsorption," J. Water Poll. Control
Fed., 47(10):2437( 1975).
11. Miyagawa, T., S. Ikeda, and K. Koyama, "Removal
of Heavy Metals from Waste Water," Japan. Kokai
122:477(1974).
13. Nagasaki, Y., and A. Terada, "Chromium-Con-
taining Waste-Water Treatment with Activated
Carbon," Japan. Kokai 750721 (1975) (in Japanese
CA08408049635J).
14. Roersma, R. E., G. J. Alsema, and I. H.
Anthonissen, "Removal of Hexavalent Chromium
by Activated Carbon," Belg.-Ned. Tijdschr.
Oppervlakte Tech. Met. Series 19, No. 2:53-56
(1975) (in Dutch CA08308065112W).
121
-------
15. Landrigan, R. B., and J. B. Hallowell, "Removal of
Chromium from Plating Rinse Water Using
Activated Carbon," U. S. NTIS AD-A Rep., No. PB-
243370:54(1975).
16. Yoshida, H., K. Kamegawa, and S. Arita,
"Adsorption of Heavy Metal Ions on Activated
Carbon. Adsorption and Reduction of Chromium
(VI) on Activated Carbon," Nippon Kagaku Kaishi
No. 3:387-390 (1977) (in Japanese CA08624176757S)
17. Huang, C. P., and M. H. Wu, "The Removal of
Chromium (VI) from Dilute Aqueous Solutions by
Activated Carbon," Water Res., 11(8):673 (1977).
18. Kim, J. 1., "Adsorption of Chromium on Activated
Carbon," Ph. D. Thesis, University of Florida, 1977.
19. Huang, C. P., and A. R. Bowers, "The Use of
Activated Carbon for Chromium (VI) Removal,"
presented at the 10th International Conference on
Water Pollution Research, July 1978, Stockholm,
Sweden.
20. Huang, C. P. and A. R. Bowers, "The Development
of an Activated Carbon Process for the Treatment
and Disposal of Chromium (Vl)-Containing
Industrial Wastewater," Preliminary Final Report to
EPA, May 1978.
122
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Removal of Heavy Metals
From Battery Manufacturing Wastewaters
By Hydroperm™ Cross-Flow Microfiltration
By Dr. John Santo, Dr. James Duncan & N. Shapira*
Charles H. Darvin**
John Baranski and Kenneth Mihalik***
SECTION
Regulations promulgated by Federal, State and local
governments place strict limits on the quantities of heavy
metals which may be released to the environment. In
some instances surcharges are imposed. Limits are
measured both in concentration and in total mass
quantities per day or month. The controlled metals
include: Ag, As, Cd, Cr, Cu, Pb, Hg, Ni, Sb and Zn.
This paper describes the results of Phase I of a two-
phase program to demonstrate the applicability of the
Hydroperm™ microfiltration system for the removal of
toxic heavy metals from lead-acid battery manufacturing
wastewaters after the metals have been chemically
precipitated. This program is being conducted under the
sponsorship of the United States Environmental
Protection Agency Industrial Environmental Research
Laboratory in Cincinnati, Ohio. The results reported
herein are from the successful laboratory testing of the
system. In Phase II, during 1979, a 24,000 gpd
Hydroperm microfiltration system will be constructed
and demonstrated at a General Battery Corporation
plant.
While the present program is directed toward treating
wastes from one specific industry, it is realized that many
other industries including the electroplating and metal
refining industries also have metal removal problems. It
is expected that the Hydroperm system will find wide
application throughout these industries.
A number of methods are presently used for metals
removal, including chemical precipitation, filtration,
electrodeposition, and cementation. However the most
widely used process is chemical precipitation. Here, a
'Dr. John Santo, Dr. James Duncan & N. Shapira
HYDRONAUTICS. inc.. Laurel, Maryland
"Charles H. Darvin
U. S. EPA Industrial Environmental Research Laboratory
Cincinnati, Ohio
•"John Baranski & Kenneth Mihalik
General Battery Corporation. Reading, Pennsylvania
chemical agent, usually lime or caustic soda, is added to
the wastewater, causing the dissolved heavy metals to
precipitate in the form of metal hydroxides. The
effectiveness of these chemical precipitation processes is
pH-dependent. For a given chemical precipitation
process, the efficiency of removal of metals also depends
on the employment of a suitable solid-liquid separation
system. The types of separation systems in use at present
usually involve gravity separation or filtration.
Filtration processes can be divided into two general
categories: cross-flow and through-flow filters. In
through-flow filtration, the flow of both feed and filtrate
are normal to the surface of the filter medium; thus the
filtered particles continuously accumulate on and within
it (see Figure 1). As a result, the filtrate flux steadily
I. THROUGH flOW FILTRATION
Id.
FILTER MEDIUM (GRAVEL,
SAND, CHARCOAL, DIATOMACEOUS
EARTH
FEATURES:
(I ) PERMEATE AND RED FLOW DIRECTIONS ARE
THE SAME
(II) INHERENTLY UNSTEADY OPERATION
(III) REQUIRES FREQUENT BACKWASHING
H. CROSS FLOW FILTRATION
Q
FEATURES:
(i ) PERMEATE aOW DIRECTION IS PERPENDICULAR
TO THAT OF THE FEED ROW
(il) PARTICLE POLARIZATION IS PREVENTED BY SHEAR
INDUCED BY THE FEED FLOW
Fig. 1—Types ol Physical MlcrofHtratlon.
123
-------
FILTRATE
tttmmtttmtmtmmn
"" "^1 -^- ]
/^ijunTHuiimiTuTimm
RJ6E WALL FILTRATE
FEED
Fig. 2—Crossflow Filtration Schematic.
decreases in time when the pressure drop across the filter
is maintained constant, and frequent "back-washing" is
necessary to remove the accumulated solids from the
filter matrix. Multimedia filters and diatomaceous earth
filters are two common examples of through-flow filters.
A different type of filtration which has been introduced
in recent years is cross-flow filtration, wherein the
direction of flow of the wastewater is parallel to the filter
surface, with the filtrate permeation occurring in a
direction perpendicular to the flow. With this process, a
quasi-steady operation is possible, since the continuous
build-up of the separated solids on the filter surface is
largely prevented by the hydrodynamic shear exerted by
the cross-flow (see Figure 2). Examples of cross-flow
filtration include microfiltration and membrane
filtration such as ultrafiltration and reverse osmosis
utilizing tubular filters.
It is relevant to point out that cross-flow microfiltra-
tion which removes primarily suspended solids, is
significantly different from membrane ultrafiltration
(UF) or hyperforation (RO) which remove substances
on the molecular level in addition to suspended solids. In
UF, higher filtration pressures (^ 50 psi) are used, with
even higher pressures (from 600-1200 psi) for RO,
compared with only ~5 psi for Hydroperm microfiltra-
tion. Furthermore, UF and RO employ relatively thin
membranes, compared with the in-depth, relatively
thick-walled (~1 mm) Hydroperm microfilters. As a
result, power requirements as well as both capital and
operating costs are much higher for membrane systems
than for Hydroperm. Another major disadvantage of
membrane filtration systems is that, under the relatively
harsh conditions characteristic of industrial filtration
applications, they are susceptible to fouling and clogging,
leading to unacceptably low filtrate flux levels. Some of
the problems associated with membrane systems are
listed in Table I below:
TABLE I
DISADVANTAGES OF MEMBRANE SYSTEMS
• Prone lo Clogging and Fouling
• "Cleaning" is Complicated
• Require Relatively High Filtration Pressures
• Prone to Leaks
• Relatively High Cost
The Hydroperm microfiltration system which was
used for the present tests utilizes thick-walled plastic
tubes whose walls are microporous, with the pore
structure and sizes being controlled during the
manufacturing process. Because of the basic ruggedness
as well as the chemical and biological inertness of the
tubes, they are not susceptible to the handling, fouling
and cleaning problems of membrane systems.
The outline of the present paper is as follows: in
Section 11 the precipitation of dissolved metals, and in
particular lead, is briefly discussed since this is the prime
importance for the success of any microfiltration system.
A description of the principal features of the filter tubes
follows in Section III which also contains some
qualitative theoretical discussions on filter performance.
The experimental apparatus and procedures used in the
present study arc described in Section IV. Results of tests
with battery manufacturing wastewaters are presented in
Section V. Section VI describes the complete Hydroperm
system planned for the field demonstration. Finally,
some concluding remarks are given in Section VII.
SECTION II
The Precipitation of Heavy Metals
The success of the cross-flow, microfiltration process
in removing heavy metals will basically depend on the
efficiency of the precipitation technique applied prior to
the Hydroperm filtration. Wastewater from battery
manufacturing plants has a low pH which leads to high
concentrations of dissolved lead. The determination of
an optimum pH for the Pb precipitation, even for a single
chemical agent, is complex. The presence of other
elements, the alkalinity of the water, temperature
variation, etc. make it necessary that an optimum
precipitation pH is established for each different
wastewater.
The solubility of lead in an aqueous solution is
substantially affected by pH. Lead dissolves, forming Pb
ions in solutions having a pH of 8 or less. In the pH range
8-11. Pb precipitates as lead oxide:
Pb: + 20H ~ PbO + H:O
Because of the amphoteric nature of lead, the PbO
dissolves in solution with a pH > 11:
PbO + 2H:O Z Pb (OH), + H'
In a Pb-carbonate-water system, the solubility of lead
depends on both pH and carbonate ion concentration. In
the range of pH 5 - 8.5 Pb precipitates as the carbonate:
Pb:* + COr ~ PbCOi
Between pH 8.5 and 12.5 lead is precipitated as cither lead
oxide or as the basic carbonate:
3 Pb:* + 2COr~ + 2H:O Z Pb,(CO):(OH): + 2H'
124
-------
TABI
,E2
Feed and Filtrate Analysis
TS
(>»g/l)
f-'ced 50.312
HItrate 2.889
ri Removal 94.26
SS Ph
(mg/l) (nig /I)
43.762 X.55
5 0.059
99.99 99.31
Cu
(»>g/l)
1.74
0.027
98.45
Zn
(mxlD
2.56
< 0.027
99.96
Ni
(nig/0
1.85
0.0028
99.85
Sb
(Wll)
0.57
0.35
38.6
Ax
(>»K/D
0.027
< 0.002
92.59
Many of the parameters, however, are interrelated. The
carbonate-biccarbonate-hydroxide alkalinity ratio is a
function of pH. Also, the concentration of calcium and
magnesium that may be present in a wastewater is a
function of both alkalinity and pH. When several
parameters are varied simultaneously, as would be the
case during wastewater treatment, it is difficult to predict
how Pb solubility will be affected.
Hydrated lime, Ca(OH):, which has been used in this
work, reacts with ionic lead forming lead hydroxide:
Pb:' + Ca(OHh - Pb(OH): 1 + Ca'"
The lime demand of a given wastewater is also a function
of the buffer capacity or alkalinity of the wastewater:
Ca(OH): + Ca(HCO.): - 2 CaCO, 1 + 2 H;O
2 Ca(OH): + Mg(HCO,) - 2 CaCO, 1 + Mg(OHfc 1 + 2
H:O
Ca(OH): + Na;CO, - CaCO, 1 + 2NaOH
In the case of the General Battery wastewaters, the
analytical results (sec Fable 2) clearly indicate that the
optimum pH for the precipitation, and consequently for
the removal of the principal heavy metals, falls into the
pH range of 9.3 -9.6.
SECTION III
Characteristic Features of Cross-Flow Filtration
The novel method of suspended heavy metals removal
described in the present paper is based on cross-flow
filtration with thick-walled, porous plastic tubes.
These tubes, which can be made from a variety of
extrudable thermoplastics by a proprietary process, have
several unique characteristics, including controlled
microporosity and ruggedness.
Hydroperm has application in a number of important
wastewater treatment roles, as follows:
• Pretreatment for suspended solids removal prior to
reverse osmosis, carbon adsorption, or ion exchange
treatment.
• Polishing, for removal of fine suspended solids after
chemical or biological treatment.
• Water Reuse, when this is otherwise impeded by the
presence of suspended solids.
• In-Plant Processes, for valuable materials recovery.
• Toxic Heavy Metals removal when in fine,
suspended form.
s
S
Fig
234567
EQUIVALENT K»E DIAMETED (p)
3—Typical Pore-Size Distribution* ol Tubes.
10
• Treatment for discharge.
The filtration characteristics of these tubes combine
both the "in-depth" filtration aspects of multimedia
filters and the "thin-skinned" surface filtration aspects of
membrane ultrafilters. For example, while the removal of
micron-sized particles and colloids is often impossible
with conventional through-flow filters, Hydroperm tubes
are capable of removing such particles. On the other
hand, in a manner similar to multimedia filters, the tubes
will allow the smaller particles and colloids in the waste
streams to actually penetrate into their wall matrix. It
should be noted that the pore structure of the tubes
differs from those of membrane ultrafilters in that the
pore sizes of the former are of the order of several
microns, with the "length" of the pores being many times
their diameters. A schematic view of cross-flow filtration
through the tubes is shown in Figure 2. The feed flow is
through the inside of the tubes at relatively low pressure
(~5 psi) and the filtrate permeation occurs through the
relatively thick (~1 mm ) tube walls.
Pore-size distributions of two typical tubes are shown
in Figure 3. Tube I has a rather "flat" distribution with
the pores ranging in size from 3 microns to 9 microns. On
the other hand Tube II has a "peaked" distribution, with
most of the pores being in the 2-micron range. They can
be made from many thermoplastics such as polyethylene,
nylon and others.
Two views of the pore structure of a typical tube are
shown in Figure 4. These photographs were taken with
the aid of a scanning electron microscope and are of a
125
-------
a ) S.E.M. 200X
S.E.M. 1000X
Fig. 4—Electron Microphotographs ol Hydroperm" Tub* Pore Structure -
Transverse Section.
transverse section of the tubes; the \ie\v in (a) has a
magnification lactor ol two hundred, while that in (h) has
a magnification lactor ot one thousand. I he open-cell,
reticulated nature ol the pore structure can be
appreciated Irom these photographs I hese leatures are
ot crucial importance in determining the performance ot
a given tube when it is used with a specific effluent, as can
be seen by considering a relatively simple model for the
tiltration process.
In general, any effluent from which suspended solids
removal is desired will contain a wide range of
particulates. ranging in diameter from several microns to
colloidal dimensions. When such effluents are circulated
through the inside ol this type of tubular filter, the solid
particles will be slowly driven, with the permeating flow.
toward the wall I hus. the concentration of the particles
in regions close to the wall will tend to steadily increase,
this tendency being delimited by the turbulent diffusion
of the particles from regions of high concentration to
those of lower concentration (that is, away from the walls
toward the center of the tube).
The turbulent diffusion (which tends to decrease the
particle concentration near the wall) is dependent on the
shear stress that is exerted on the walls h\ the cross-flow
cnculation. and. hence, its velocity. On the other hand.
the permeation rate (which tends to increase the particle
concentration near the wall) depends on the pressure
differential across the tiller surface (I'oiseuille's law) as
well as the pore structure ol the tubes (Darev's law). A
quasi-steady state profile ol the concentration ol the
particles will be established near the wall, when the two
opposing tendencies mentioned above exactly balance
each other. The resulting "particle polari/ation" in this
case is entirely analogous to the "concentration
polari/ation" ol solutes that occurs close to walls ol
ultraliltration and reverse-osmosis membranes.
Because ol the in-depth filtration characteristics of the
tubes, other factors also come into play. Specifically,
particles which are smaller than the largest pore si/c ot
the lubes can actually enter the wall matrix, while-
particles which are larger than all of the pores in the tubes
will be retained at the walls. I his feature is illustrated
schematically in Figure 5, which shows the parliclc-si/e
distribution in the feed plotted on the same scale as the
pore-si/e distribution ol the liltration tubes. The shaded
region represents the particles which are smaller than the
largest pore si/e and can thus enter the wall matrix. These
particles will remain within the wall ol the tube because of
the irregular and tortuous nature ol the pores. I hus as
liltration proceeds, the pore structure of the tube as well
as its permeability will undergo a gradual change due to
the penetration ol some ol the pores by the intruder
particles. However, the tendency of new particles to enter
the tube matrix will decrease as a line, dynamic filter cake
forms on the walls due to particle polarization described
earlier. Clearly, both the change in the pore structure and
INITIAL PORE SIZE
DISKWUTION
INITIAL PAKTICIE SIZE
DISTIIIBUTION
1
\
Porticl« retained ot
". I, 11 p. tulfoCI
Fig. 5—Schematic ol the Suspended Solids Penetration ol the
Hydroperm" tube matrix.
126
-------
the properties of the filter cake will be strongly influenced
by the shaded overlap region in Figure 5 and,
consequently, so will be the filtration performance.
Even from the relatively simple, qualitative discussion
given above, it is clear that the filtration performance is
influenced not only by such factors as the filtration
pressure, circulating flow velocity and temperature
(which changes the fluid \ iscosity and, hence, by Darcy's
law, the permeation rate), but also by the pore-si/e
distribution, pore structure and the particle-si/e
distribution in the wastes. As mentioned earlier, the
unique feature of these tubes is that their pore
characteristics can be "tailored" (that is. controlled in a
systematic manner) to suit the characteristics of a given
waste effluent.
SECTION IV
Kxperimental Apparatus and Test Procedures
The experiments described in the present paper
consisted of tests mostly with single tubes, though tests
with small modules containing a "bundle" of several
tubes are also typically performed. The inside diameters
of the single tubes tested were either 4 mm, 6 mm or 9
mm, and they had a length of about 46 cm so that their
filtration-surface area ranged from about 57 cm- (9 in.:)
to 130 cm- (20 in.:). A schematic view of a typical single-
tube loop is shown in Figure 6. As indicated in the figure,
the loops contain a feed reservoir (~5* gallons capacity).
a circulating pump, a How meter, pressure gauges to
measure pressure drops over the length of the tubing
being tested and appropriate val\ ing. Portable test loops
essentially like that shown in Figure 6, have also been
used at plant sites to conduct tests "in situ"
Basically, two different modes of operation are used
when carrying out the tests. In the first, which is the one
most often used and simulates "continuous-mode-
operation in a prototype system, the permeate is remixed
into the feed reservoir, so that (except for evaporation
losses) the volume of the circulating feed, as well as its
suspended-solids concentration, remain constant. The
feed in the reservoir is replaced at appropriate intervals to
eliminate changes in characteristics due to biological
activity and/or constant recirculation.
In the second mode of operation, "concentration", a
batch-wise process in a field prototype system is
simulated. Here the permeate is collected in a separate
reservoir, so that the volume of the circulating feed
continuously decreases while its suspended-solids
concentration continuously increases. The tests are
continued until a specified feed concentration is reached
or until the volume of the feed becomes so low that
adequate pump suction from the reservoir can no longer
be maintained.
Results from a wide variety of tests have demonstrated
that the Hydroperm tubes are capable of virtually total
PERMEATE
COLLECTING
FlOW f] JACKET
METER "^
PRESSURE /
GAUGE V
THERMOMETER-
\ /
PUMP
t
^
t
i
i
_
f
*
•-r
7\JI
2H
•X
r±
55;-^
•s^s
\
PRESSURE GAUGE
FILTRATION
TU8E
V EVAPORATION LOSS
^^ COMPENSATION LINE
FEED
LINE
PERMEATE
* LINE
-:r-r-=:a
*" " n
fe TEMPERATURE
^ 1 | CONTROL
RESEttVOlR 1 J
*A 55-g:il drum rcscrvon »,is .iclualh uxcd in llus U'-i program.
Fig. 6—Schematic of a Single-Tube Hydroperm" Test Loop.
removal of suspended (including colloidal) solids at
relatively low filtration pressures, and even at high feed
concentrations. Indeed, in most cases, the suspended
solids concentration in the permeate is nearly
independent of the value in the feed, displaying only a
negligible residual value. It is also relevant to note that in
spite of the micron-size pore structure and the lo\v
filtration pressures, in many cases Hydroperm tubes have
also yielded significant reduction in dissolved solids. The
tubes also achieved complete separation of oil from
water.
SECTION V
Tests with Battery Manufacturing Wastewater
The wastewater used for the present tests was obtained
from a General Battery Corporation plant. The raw
wastewaters contained ~ 1500 - 1900 mg/1 of total solids
with ~ 20 - 200 mg/1 of suspended solids and ~ 10 - 20
mg/1 of lead. When received, the wastewater had a pH of
~ 1.2. Toxic heavy metals included Pb, Cu, Zn, Ni, Sb
and As. The dissolved metals were precipitated at a range
of pH's by adding hydrated lime. The best results were
obtained at a pH of 9.3 - 9.6. After lime addition, TS
values increased to ~ 45,000 mg/1 in the feed, most of
which were in the form of SS (~ 40,000 mg/1).
A number of single tube tests of up to 160 hours in
duration were performed with the lime-precipitated
waste described above. In all but one of the tests the
filtrate was remixed with the feed, which resulted in a
"constant concentration" mode of operation. One test
was performed with increasing suspended solids
127
-------
concentrations in the feed, which resulted from the
periodic removal of the filtrate from the feed until an 85%
reduction in the total volume of the feed had been
reached. The purpose of these tests was to provide
information on filtrate flux and quality as a function of
the type of tube and the operating conditions used. This
information is necessary for tube optimization in pilot-
plant design.
A typical plot of filtrate flux versus time in hours is
shown in Figure 7. The tube used for this test had an
internal diameter of 6 mm and the pore structure was that
depicted in Curve I of Figure 3. The operating conditions
consisted of a feed pressure of 5 psi, a feed velocity of 4
ft/sec and a temperature of 35° C. In this constant-
volume test, the filtrate was remixed with the feed. Note
from Figure 7 that the flux begins at ~ 1,000 gal/ft2-day
and typically declines almost immediately, with the rate
of decline decreasing with time. From this curve and
experience with other wastes it can be estimated that
steady "plateau" fluxes of from 150 to 250 gfd could be
maintained for several days without any tube cleaning.
However, after 40 hours in the present test, the tube was
cleaned by operating the tube normally with a water
solution of 0.25% Servac (a mild phosphoric acid
containing commercial cleaner) in water for a period of
15 minutes. Dilute HC1 (~3 %) was also used
successfully. Note from the figure that when the test was
started again the flux had been restored nearly to its
original value (~ 1,000 gfd), after which it began to
decline again. The second flux decline was not as rapid as
it was in the first part of the test. This behavior frequently
occurs, probably because of changes in the feed during
pumping, and changes in the pore structure resulting
from penetration of fine suspended solids into the pore
matrix.
A total of twelve single-tube tests have been performed
GENERAL BATTERY
HYD. TUBE NO. 6-26-78 II- G3{NY)
1.0. - 6mm
V 4.0 FT AEC
P 5(.i
T 35° C
1200
thus far, with: 2 tube pore types (the ones shown in Figure
3); 3 tube internal diameters (4 mm, 6 mm and 9 mm);
with: feed velocities (7 ft/sec and 4 ft/sec); and one feed
pressure (5 psi). The results for the constant feed
concentration tests in terms of filtrate flux demonstrated
the influence of several important parameters. First, the
pore structure had a significant influence on flux, since
the tube with the wide pore-size distribution had a flux of
250 gal/ft2-day after 40 hours, while the tube with the
narrow distribution had a flux of 50 gal/fr-day after only
2 hours of operation. The effect of feed velocity was also
significant, since for the 7 ft/sec tests the filtrate flux after
40 hours was about 100 gal/ft 2-day higher than that for
the 4 ft/sec tests. The tube diameter, on the other hand,
was found to have little or no influence on flux. These
findings are consistent with the description of the physics
of the filtration process given in Section 111. The above
results are important for design purposes, since the flux,
feed velocity, and tube diameters will all have an
influence on economics in terms of materials cost and
power requirements.
The flux record for the test which was done with
increasing feed concentrations is shown in Figure 8 (~200
gfd at 160 hours). The tube type is the same as Tube I
shown in Figure 3. However, the internal diameter here is
4 mm. The test conditions are given in Figure 8. Note
from the figure that the test was operated in the constant-
concentration mode for most of the 160 hours of testing,
however, during four 3- to 7-hour intervals, the filtrate
was removed from the feed. Thus, the concentration of
suspended solids in the feed increased in four steps during
the test. During the final part of the test, the total feed
volume had been reduced to only 15% of its original
value. The flux levels in the figure show that, even with
this high feed concentration, fluxes of around 200 gallons
/ft2-day can be achieved.
Having established typical flux rates and the
dependence of these rates on certain operating
parameters, one turns now to filtration performance in
terms of filtrate quality. During the above tests, samples
of the feed and filtrate were analyzed periodically for
total solids (TS), suspended solids (SS), lead (Pb),
Copper (Cu), Zinc (Zn), Nickel (Ni), Antimony (Sb), and
Arsenic (As). Atomic adsorption was the analytical
method used. From these analyses it was found that the
filtrate quality was independent of any of the operating
10 20 30 40 50 60 70
TIME - Hn.
Fig. 7—Permeate Flux Result*.
80
•ool
too
400
200
0
—
5
O <
__ 1
I
>A
?
n
<&
9°?
r i n
-*?
I 0
Oil-
HYO
_ 1.0
V
f
I
n
CIAL IATTUY
. TUMNO. M-I4-71III -Of
7.0H/SK.
J|»l
XfC
SIAIt CONCtNTlMIOK
SIAIT KCYCU MOM
Yo
i
(NY)
MOM '
) JO 40 60 M 100 110 140 160 110 201
Fig. 8—Permeate Flux Retultt.
128
-------
Fig. 9—Hydroperm™ Module.
conditions or tube types mentioned above. A typical
comparison of the analysis of the feed and filtrate
samples is shown in Table 2. Note from the table that the
suspended solids content of the feed of 43,762 mg/1 was
reduced to 5 mg/1 in the filtrate, and that lead was
reduced from 8.55 mg/1 to .059 mg/1. These excellent
rejection percentages also hold for the other heavy metals
tested, as shown in the table. However, it should be
pointed out that, while microfiltration achieves virtually
complete removal of suspended solids, the quantity of
total metals converted to SS form is dependent upon
definition of an optimum pH for precipitation. In this
case, the optimum pH for lead removal is ~9.3 - 9.6.
SECTION VI
The HYDROPERM™ System
The basic element of the Hydroperm microfiltration
system is, of course, the tubular filter element that was
described in Section III. The design of the total system
primarily involves combining large numbers of these
tubes with a feed reservoir in a manner which is
economical in terms of capital and operating costs. The
design approach utilized at present is to combine groups
of tubes into modules which make up the basic building
blocks of any system.
A number of steps are required in total system design,
starting with tube optimization and proceeding to
component selection and sizing. The modules can be
optimized in terms of their length and diameter, number
of tubes contained, type of end-fitting used, and so on. A
typical module is shown in Figure 9. The arrangement of
the modules can also be optimized in terms of whether
they are arranged in series, in parallel, or in a
combination. The criteria used for the last two
optimization steps are ease of handling, ease of
maintenance, ease of installation, power requirements,
space constraints, as well as capital and operating costs
(see Figure 10).
When compared with other systems, the system of this
program offers several unique advantages. These are
summarized below:
(a) Compactness: The microfiltration system does not
require large spaces, they can be engineered to fit
available space.
(b) Flexibility: Various estimates place the number of
electroplating and metal finishing companies in the
U.S. at well in excess of 10,000. Many of these are
small. Because of its modular construction, the
microfiltration system can be designed to
accommodate a full range of wastewater treatment
requirements, from small to large.
FILTRATE
DISCHARGE
FOR REUSE OR
TO CARBON
COLUMN
FILTRATE FLOW
CIRCULATING FEED ROW
CLEANING FLOW
FILTRATE FLOW
2-WAY VALVE
PRESSURE GAUGE
TEMPERATURE GAUGE
FLOW METER
VENT
SAMPLE PORT
FROM WASTER WATER
LAGOON
SLUDGE REMOVAL
Fig. 10—Schematic Hydroperm™ Wastewater Treatment System.
129
-------
(c) Versatility: Since the microfiltration system is
excellent in removal of suspended solids and oils as
well as substantial dissolved solids, the permeate can
be either directly recycled in cases where the presence
of some dissolved solids does not bar such water reuse,
or it can be discharged into sewer systems or natural
waters.
(d) Ruggedness: Since they are made from inert
thermo-plastics, the performance of the tubes does not
depend, in general, on changes in influent pH.
Moreover due to their rugged structure and low
operating pressure, the modules are not subject to the
fouling and leaking problems which have plagued
some membrane systems; nor are they subject to
clogging in the presence of oily wastes.
(e) Ease of Maintenance: Because of their ruggedness
and modular construction, the microfiltration system
is easy to maintain. It can be engineered in such a way
that a failure in a given module causes only a small part
of the total system to be shut down.
(0 Product Recovery: In many cases product recovery
is possible.
The virtually total absence of suspended solids in the
permeate from the tubes makes the permeate ideally
suited for ultimate treatment, when necessary, for the
further removal of dissolved solids by carbon or resin
columns, or RO membranes, so as to produce a
completely reusable or dischargeable water.
SECTION VII
Summary
The excellent results of Hydroperm performance in
terms of flux and permeate quality reported herein are
typical of the use of the Hydroperm separation system
with a number of other wastes. It should be pointed out
that the results of the heavy metals separation tests
described herein are not dependent on either the fact that
the wastewater containing the heavy metals is from a
battery manufacturing plant or that the metals were
precipitated with lime. Removal by Hydroperm of
various metals in suspended solid form as a result of
precipitation by chemicals other than lime would still be
just as effective. Thus, the results described herein would
appear to have widespread application throughout the
metal finishing industry. If either the waste
characteristics or the precipitant were to be changed, it is
clear from past Hydroperm tests (with Zn, Cu, Cd and
Ni) that results similar to those reported herein in
suspended solids removal would be obtained by
appropriate changes (if necessary) in tube pore-size
distribution and' operating conditions. Tube
performance in removal of SS is substantially
independent of the type of metal or concentration.
References
1. Henry, J. D., Jr., "Cross Flow Filtration," Recent
Developments in Separation Science, Volume 2,
CRC Press, pp. 205-225, 1972.
2. Duncan, J. D., Sundaram, T. R., Fruman, D. H. and
Santo, J. E., "A Unique Microfiltration System for
Treating Industrial Effluents." Paper presented at
the Second International Congress on Industrial
Effluents." Paper presented at the Second
International Congress on Industrial Waste Water
and Wastes, Stockholm, Sweden, February 1975.
See also. Progress in Water Technology, Vol. 8, Nos.
2/3, pp. 181-189, Pergaman Press, 1976.
3. Sundaram, T. R. and Santo, J. E., "Removal of
Turbidity from Natural Streams by the Use of
Microfiltration," HYDRONAUTICS, Incorporated
Technical Report 7662-1, June 1976.
4. Sundaram, T. R. and Santo, J. E., "Microfiltration
of Military Waste Effluents," Seventh Annual
Symposium on Environmental Research—Meeting
Report (Ed: J. A. Brown), American Defense
Preparedness Association, Washington, D. C.,
September 1976.
5. Sundaram, T. R. and Santo, J. E., "The
Development of a HYDROPERM™ Microfiltration
System for the Treatment of Domestic Wastewater
Effluents," HYDRONAUTICS, Incorporated
Technical Report 7658-1, January 1977.
6. Sundaram, T. R. and Santo, J. E., "Removal of
Suspended and Colloidal Solids from Waste Streams
by the Use of Cross-Flow Microfiltration." ASME
Publication No. 77-ENAS-5I, July 1977.
7. Bear, J., Dynamics of Fluids in Porous Media,
American Elsavier Co., 1972.
8. Sundaram, T. R. Santo, J. E. and Shapira, N. 1., "An
In-Depth, Cross-Flow Separation Technique for the
Removal of Suspended Solids from Wastewaters,"
Industrial Water Engineering, January/February
1978.
9. Sundaram, T. R. and Santo, J. E., "Development of
a Hydroperm™ Microfiltration System for the
Treatment of LAP Army Ammunition Plant
Wastewater Effluents," HYDRONAUTICS,
Incorporated Technical Report 7830-1, February
1978.
10. Sundaram, T. R. and Santo, J. E., "The
Development of a Hydroperm™ Microfiltration
System for the Treatment of "MUST' Hospital
Wastewater Effluents," HYDRONAUTICS,
Incorporated Technical Report 7760-1, October
1977.
130
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Status of Analytical Methods for Cyanide
Gerald D. McKee*
Introduction
The monitoring of cyanide in waste effluents is
required by the U. S. Environmental Protection Agency
to determine the "Total Cyanides" and the "Treatable
Cyanides," cyanides amenable to chlorination, being
discharged to a water body. The EPA approved method1
for measuring "Total Cyanides" does not measure
thiocyanide compounds or organic cyanides that do not
decompose or hydrolyze in mineral acid to cyanide ion.
The EPA approved method2 for measuring "Treatable
Cyanides" is based on the well known cyanide
destruction by oxidation with chlorine or hypochlorite.
Total cyanide is measured before and after an alkaline-
chlorination treatment of the sample and the difference is
termed "Cyanides, Amenable to Chlorination." Several
methods have been developed for the determination of
cyanides based on the ease of dissociation of cyanide
compounds using different experimental conditions.
This has brought about a whole host of less than
descriptive terms for cyanide, including "free," "simple,"
"easily dissociable," complex," and "non-dissociable"
cyanides. The dissociation of most inorganic cyanide is a
function of pH. Heat, catylsts or inhibitory agents are
commonly used to increase or decrease this dissociation
and subsequent removal of cyanide ion from the sample
for measurement. All of the methods discussed use either
pyridine-barbituric acid or pyridine-pyrazolone for
colorimetric development, titration with silver nitrate or
an ion-selective electrode (1SE) for final quantitative
measurement of cyanide. These measurement techniques
are discussed as a part of the total cyanide procedure.
Methods for Less than Total Cyanide
A method for measuring "free" cyanide using a
Conway micro diffusion cell has been proposed for use by
the American National Standards Committee on
Photographic Processing, PH4.1 Cyanide measured by
this technique is defined in this method as "the cyanide,
bound or otherwise, which can easily form hydrogen
cyanide (HCN) from an acidified solution." A small
sample volume (3 ml) is placed in the outer ring of the cell,
treated with cadmium chloride to precipitate
hexacyanoferrates and buffered to pH 6. An airtight lid is
placed on the cell and the HCN gas diffuses into the
center chamber of the cell which contains sodium
•Gerald D. McKee, U. S. Environmental Protection Agency
Environmental Monitoring and Support Laboratory
26 W. St. Clair Street, Cincinnati. OH 45268
hydroxide. This diffusion process takes from four to
eight hours to reach equilibrium. Measurement of the
cyanide that has diffused into the sodium hydroxide is
made with pyridine-barbituric acid. This procedure ;is
operator dependent and the cyanides recovered from
complex wastes are not well defined.
Mellon Institute developed a method4 for the
American Iron and Steel Institute (AISI) to measure
"simple or free cyanides and certain other easily
dissociated complex cyanides." Glassware similar to that
required for total cyanide measurement is required. The
sample is placed in a flask and acidified to pH 4 with
sulfuric acid. The HCN formed under these conditions is
drawn from the sample by an air flow of 3 litres per
minute for 2 hours into a sodium hydroxide scrubber.
This method reportedly recovers more than 90 percent of
cadmium, zinc, and nickel cyanide complexes and 61
percent of a copper cyanide compound. Ferro and ferri
cyanide compounds are not recovered. This method is
sensitive to glassware design and rate of air flow.
An electrode technique for measuring cyanide
published by Riseman5 recommended freeing the cyanide
ion from metals such as nickel and copper with a
preliminary heating step to 50° C for 5 minutes in the
presence of ethylene diamine tetraacetate (EDTA). Thjs
heating step is carried out on a sample acidified to pH 4
with acetic acid. The sample is then made basic and the
cyanide ion measured by a cyanide electrode. This
preferential complexing by EDTA releases cyanide ion
from some of the metal complexes but cyanide ion
present in the original sample is partially lost during the
heating step at pH 4.
A similar procedure is published by the American
Society for Testing Materials (ASTM), D2306-75,
Method C, "Cyanide, Amenable to Chlorination without
Distillation (Short Cut Method)."6 This procedure
requires heating the sample to 50°, C for one minute
followed by direct colorimetric measurement. The pH of
the sample during the heating step is not specified and
consequently, very different answers can result from a
sample analyzed at different pHs. In addition to the
volatility of hydrogen cyanide, if the pH is greater than
12, cyanogen chloride originally present in the sample
will be hydrolyzed to cyanate and not measured,
thiocyanate if present, will react with the color reagent
and be reported as cyanide. This method when used
under controlled conditions, such as an individual waste
stream with constant characteristics will produce results
adequate to aid in required treatment but the lack of
131
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precisely defined test conditions make this procedure
inadequate for monitoring various types of effluent.
The "Roberts and Jackson Method"7 was developed to
measure "cyanide" in the presence of ferrocyanide. The
sample is mildly acidified and a heat distillation is carried
out under reduced pressure in the presence of zinc acetate
to prevent the decomposition and distillation of
ferrocyanide. The released cyanide is collected in sodium
hydroxide measured with pyridine-pyrazolone.
This procedure has been modified to use an acetate
buffer to maintain a sample pH of about 4.5 throughout
distillation and is currently being considered for
adoption by ASTM. Cyanide is recovered from zinc
and nickel complexes but not from ferro, ferri and cobalt
cyanide compounds. Recoveries from copper and
cadmium cyanide compounds were 72 and 33 percent,
respectively.
The Environmental Monitoring and Support
Laboratory (EMSL) conducted an interlaboratory study
for cyanide analyses, EPA Methods Study 12," that
included the Roberts and Jackson, Cyanides Amenable
to Chlorination, by Difference and the Total Cyanide
methods. Concentrated solutions of potassium cyanide
ranging from 13 to 149 ug/1 in the presence of iron
cyanide ranging from 12 to 223 ug/1 when properly
diluted were sent to participants. The study participants
added these concentrated solutions to a natural water of
their choice and analyzed for cyanide by one or all of the
methods.
Only three laboratories submitted data for the Roberts
and Jackson method and, therefore, the results are of
limited value but are presented here because of the
method's apparent good precision and accuracy. These
data show a 95 percent recovery of potassium cyanide in
the presence of iron cyanide and a relative standard
deviation of 7.5 percent at a concentration of 80 ug/1.
Cyanides, Amenable to Chlorination2 is the difference
between the measurement of Total Cyanide1 before and
after an alkaline Chlorination step. This procedure is the
only method approved by the Environmental Protection
Agency for effluent compliance monitoring of "Less than
Total Cyanide." The Chlorination step is carried out at a
pH between 11 and 12 for one hour while maintaining an
excess of chlorine.
EMSL has used this method to less than 50 ug/1
cyanides amenable to Chlorination and estimate the
intralaboratory relative standard deviation to be
approximately 30 percent at 80 ug/1. At this same
concentration, in EPA Methods Study 12, this procedure
was found to have a positive bias of 141% using pyridine
pyrazolone, 106% using pyridine barbituric acid, and
120% using the 1SE for the final measurement system.
The interlaboratory relative standard deviation was
determined to 69, 73, and 126 percent using pyridine-
pyrazolone, pyridine barbituric acid and the 1SE,
respectively at 80 ug/1 of cyanide amenable to
Chlorination.
Methods for Total Cyanide
An automated method using a continuous flow thin
film evaporation for dissociable cyanides and high
intensity ultraviolet irradiation to decompose ferri, ferro
and cobalt complexes (total cyanide) was developed by
Kelada.9 This method also includes a measurement of
oxidizable (using ozone) cyanides and thiocyanates by
difference. This method is rapid and precise, but some
difficulties have been experienced with various degrees of
cyanide complex destruction using different UV light
sources. Technicon has a method similar to the method of
Kelada.
The EPA approved procedure for Total Cyanide1 is an
acid refux distillation. The sample is made highly acidic
and magnesium chloride catalyst is used to aid recovery
of iron cyanide compounds. The cyanide released from
the sample is absorbed in a sodium hydroxide scrubber
solution and the cyanide is measured either
colorimetrically or titrimetrically. The ISE measurement
technique is currently being investigated but is not
currently an approved technique for National Pollutant
Discharge Elimination System (NPDES) monitoring.
In the EPA Methods Study 12 to determine the
precision and accuracy of the total cyanide procedure,
data were calculated separately for those analysts using
the pyridine-barbituric acid, pyridine-pyrazolone and the
ISE. For concentrates added to natural water of the
analysts choice, the interlaboratory relative standard
deviations at 240 ug/1 total cyanide were 18 percent using
pyridine-pyrazolone, 30 percent using pyridine
barbituric acid and 38 percent using the ISE. The percent
recovery using pyridine-pyrazolone was 96 percent, 91
percent using pyridine barbituric acid and 100 percent
using an ISE.
Although this study did not include a concentration
quite as high as 640 ug/1, calculated estimates of relative
standard deviation based on this study are consistent
with intralaboratory data and are presented with that
qualification. The interlaboratory relative standard
deviation at 640 ug/1 total cyanide are estimated to be 13
percent using pyridine pyrazolone, 27 percent using
pyridine-barbituric acid and 28 percent using the ISE.
Intralaboratory studies estimate the relative standard
deviation from 240 to 640 ug/1 total cyanide to be
between 11 to 14 percent with a detection limit of about
20 ug/1 total cyanide.
Problems Associated with Total Cyanide Methodology
As you are aware, the proposed rules for total cyanide
discharge limit are: 240 ug/1 for a 30-day average and/or
640 ug/1 for a daily maximum. 1 will confine my discusion
to analyses of total cyanide at these concentration levels.
As with any analyses, the number of manipulations
involved increases the potential for error in the final
result due to the variability introduced at each step.
The first step that error may be introduced is
immediately after sample collection. The alkaline-
chlorination decomposition of cyanide is well known
and, therefore, chlorine, if present, must be removed
132
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prior to preserving the sample with sodium hydroxide.
The procedure states that the sample should be checked
with potassium iodide-starch test paper (Kl-starch
paper) for the persence of oxidizing reagents. There are a
number of reports about the insensitivity of the K I-starch
paper. It was reported by one individual (EPA-Region I)
that the Kl-starch paper being used did not detect less
than 10 mg/l chlorine; other users have verbally reported
detection limits of 5, 2, 0.5 mg/l chlorine. The Kl-starch
paper must be kept dry and out of sunlight if the
sensitivity is to be maintained. Certainly, there will be
significant differences in reported concentrations of
cyanide if these high levels of chlorine are present in some
samples when the sample is preserved with sodium
hydroxide to a pH of 12.
Two other optional pretreatment steps may affect the
final results. Sulfides, if present in the original sample,
will also distill under the acid conditions as hydrogen
sulfide and be trapped in the alkaline scrubber resulting
in an adverse affect both in the colorimetric and the ISE
procedures. The approved method recommends a test for
the presence of sulfide using lead acetate test paper. If
present, the sulfide is removed from the sample by
filtration following precipitation with cadmium
carbonate. Both the initial test for sulfide and its
subsequent removal have a potential for producing error.
The first error is the possibly poor sensitivity of the lead
acetate test paper to detect low levels of sulfide and the
second is the treatment with cadmium carbonate and
filtration step. Formation of the precipitate and filtration
may sorb some of the cyanide complexes and whether
this process is physical, mechanical or a loose chemical
attraction, the porosity of the filter paper, rate of
filtration, time required for the cadmium sulfide
precipitate to form, pH, solids originally present in the
sample, and the amount of precipitate formed will affect
the amount of the cyanide present in the filtered sample.
Fatty acid removal is another step that may introduce
error but is not pertinent to this industrial waste.
Another area of potential imprecision in the
determination is the rate of distillation. This is a minor
area of concern and lessens as the analyst acquires
experience with the procedure. The rate of the vacuum
distillation changes and requires readjustment as heat is
applied to the sample in order to maintain a contact rate
of distillation.
Another area of the analysis that may cause differences
in the reported concentrations is the use of different
catalysts in the distillation step. The procedure as written
in the 1974 edition of Methods for the Chemical Analysis
of Water and Wastes states that copper chloride is to be
used as the catalyst. The December 1, 1976 Federal
Register, Vol. 41, No. 232'° references the 1974 EPA
method but a footnote in the Federal Register
recommends the use of magnesium chloride (MgCb) for
samples suspected of having thiocyanate present. Other
referenced procedures in the above cited Federal Register
recommend the optional use of these catalysts. The use of
different catalysts in some sample types will result in
widely differing reported concentrations and the catalyst
used must be known when comparing data. The 1979
Methods for Chemical Analysis of Water and Wastes will
include only the use of MgCl:.
The procedure used for preparing a standard curve can
also produce an inherent and unnecessary wobble. If the
standard curve is prepared using non-distilled standards,
the curve will be approximately ten percent more precise
and also more accurate than distilling all of the standards
since any error introduced during distillation is
eliminated. It is essential that the identical concentration
of sodium hydroxide be used to prepare the standards as
will result from dilution of the scrubber solution.
Then after preparing a standard curve using non-
distilled standards, the distillation technique should be
checked by distilling standards. This procedure for
standard curve preparation is also less time consuming
and will produce a more precise and accurate standard
curve and also ensure the entire procedure is working
well.
There are two approved procedures for measuring the
cyanide in the sodium hydroxide solution of
concentration levels of interest. Either pyridine-
barbituric acid or pyridine-pyrazolone may be used to
develop a cyanide complex that may be measured
colorimetrically. The time of reaction for the cyanide and
the chlormine-T and the time of reaction between the
cyanogen chloride and either color reagent must be kept
identical with the standards and samples. This is
especially critical for pyridine-barbituric acid. The 1974
approved procedure recommends adding the color
reagent immediately after addition of the Chloramine-T;
better precision is obtained when this time for reaction
between cyanide and the Chloramine-T is held constant
at about two minutes prior to addition of the color
reagent. Many of these problems have been corrected in
the 1979 edition of Methods for Chemical Analysis of
Water and Wastes.
Summary
The Roberts and Jackson method for "less than total
cyanide" is not an EPA approved Method but based on
limited data appears to be adequate for measuring
cyanides except for cobalt and iron cyanide complexes
and is accurate and precise.
The EPA approved method for measuring "less than
total cyanide," Cyanide Amenable to Chlorination,
involves two complete measurements for total cyanide
and a Chlorination step. This procedure has an
interlaboratory relative standard deviation
approximately 70 percent at the proposed limit for
Cyanides Amenable to Chlorination.
The approved procedure for Total Cyanides is a classic
procedure that requires analyst experience. The
procedure is accurate and has an interlaboratory relative
standard deviation of 13 to 18 percent using pyridine
pyrazolone for color development at the proposed
discharge limits for Total Cyanide from the
Electroplating Point Source Category.
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All analytical methods, even when used in the best
laboratories by the best analytical chemists, require an
adequately implemented quality assurance program that
includes proper calibration, routine calibration check,
analyses of duplicate and spiked samples and laboratory
participation in round-robin studies.
References
1. "Methods for Chemical Analysis of Water and
Wastes," Environmental Monitoring and Support
Laboratory, Environmental Research Center, U. S.
E. P. A. Cincinnati, Ohio 45268; Method 335.2,
1979.
2. "Methods for Chemical Analysis of Water and
Wastes," Environmental Monitoring and Support
Laboratory, Environmental Research Center, U. S.
E. P. A., Cincinnati, Ohio 45268; Method 335.1,
1979.
3. American National Standard Method (Proposed)
for Determining Microdiffusion Free Cyanide in
Photographic Effluent," American National
Standards Institute, 1430 Broadway, New York,
N.Y. 10018, 1976.
4. "AISI Aeration, Recommended Method for the
Analysis of Simple Cyanides in Water," Mellon
Institute, Pittsburgh, PA, (1978).
5. Riseman, J., "Electrode Techniques for Measuring
Cyanide in Waste Waters," American Laboratory, 4,
(12), p. 63, 1972.
6. "Annual Book of ASTM Standards," Part 31,
Water, American Society for Testing and Materials,
1916 Race St., Philadelphia, PA 19103, D 2036-75,
Method C, 1978.
7. Roberts, R. F. and Jackson, B., "The Determination
of Small Amounts of Cyanide in the Presence of
Ferrocyanide by Distillation under Reduced
Pressure," Analyst, 96, p. 209, 1971.
8. EPA Methods Study 12, Cyanide in Water,
Environmental Monitoring and Suppor Laboratory,
Environmental Research Center, U. S. E.P.A.,
Cincinnati, Ohio 45268; In Press.
9. Kelada, N. P., Lue-Hing, C, and Lordi, D. T.,
"Cyanide Species and Thiocyanate Methodology in
Water and Wastewater," Metropolitan Sanitary
District of Greater Chicago, Report No. 77-20,1977.
10. "Federal Register," Guidelines Establishing Test
Procedures for the Analysis of Pollutants, 40, (232),
December 1, 1976.
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Prudent Waste Treatment Monitoring,
Analytical Control, and Testing
By Frank Altmayer*
ABSTRACT
It is not difficult to find reports offish kills, chemical spills, and discharges of insufficiently
treated waste in your daily newspaper. The tragic element in these stories is thai a majority of
these catastrophic could have been avoided ft adequate monitoring and control of waste
treatment systems had been performed. This paper shall detail the simple analytical and
monitoring tools available for achieving good waste treatment.
All of you work for companies which have recently
added a new product line. This new product differs from
your ordinary lines of business in many ways, and yet
there are some important similarities. This new product
must meet constantly increasing quality requirements; its
consumer products safety liability aspects are at least as
frightening as for any other products you manufacture.
The cost of raw materials to produce it are increasing
rapidly and yet your customer is a reluctant recipient who
charges you for accepting it, and this product, therefore,
creates negative sales. Your new product is ecologically
acceptable waste water.
As with any other product, the production of a
satisfactory waste water requires not only a
manufacturing facility commonly called a waste
treatment system but careful step by step control of the
entire process of waste treatment. One should consider
waste treatment a manufacturing process and apply the
same monitoring as are common in production of other
manufactured goods. These would include controls to
insure a consistent treatable raw material, process
control, in process inspection, and final inspection. The
purpose of this paper is to discuss the simple tools that
are available for achieving effective monitoring.
CHOOSING THE CONTROL TECHNIQUE
When choosing the control method for any phase of
waste treatment a prudent evaluation must be made as to
the degree of control necessary. For instance, for the first
step of chlorination of a cyanide effluent it is necessary
that the pH remain above 10.S; but a pH of 12 or higher
will create no problems. On the other hand, for optimum
clarification of mixed metal effluents, it may be necessary
'Frank Altmayer
Scientific Control Labs.. Inc.
3158 South Kolin Avenue. Chicago. IL 60623
to control the pH to ±0.1 units. The control methods will
vary greatly for these two operations.
Another way in which the necessary degree of control
and preciseness of measurement would vary would be
whether one's effluent closely approaches the legal limits
or if it meets it very comfortably. A company that
discharges zinc to a Metropolitan Sanitary District with a
limit of IS mg/l will require a different degree of
monitoring if their effluent is consistently in the 5 to 7
mg/l range than if its discharge is consistently 12 to 14
mg/l. In the latter case, they either should improve their
waste treatment to have a greater margin of safety or have
a very precise control of each phase of treatment.
The selection of control method should also be based
upon availability of materials and equipment and
operating materials, operator skill required, time for
testing, accuracy and precision obtainable, and
acceptance of test results by others, if required.
Chemists and waste treatment operators tend to be
empire builders. They frequently fall in love with precise,
expensive equipment. This characteristic, if unchecked,
often leads to poor waste control. For instance, hourly
observance of the pH using pH papers accurate to ± 0.2
pH units is more effective monitoring than once a day
monitoring using a pH meter accurate to ±0.01 pH units.
A wide variety of "tools" are available in waste
treatment. They vary from the very simplest to very
sophisticated. The goal should be to use the simplest.
effective tool. Some of these arc:
A Waste Treatment Manual
It is surprising how few companies have a manual
describing the waste treatment equipment, the function
of each separate section, and the proper control
monitoring. Such a manual is a must for effective waste
treatment. In addition to the above, the manual should
detail the type and frequency of inspection to be carried
135
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out at each treatment step and the remedial steps to be
taken in case of an upset.
Sight and Smell
The most important aspect of monitoring a waste
treatment system involves the use of one's sight and sense
of smell, and yet, very few waste treatment manuals
adequately instruct the operators on what to observe, the
frequency of observation, or the significance of what they
are observing.
A big fear, for any company discharging waste waters,
is the catastrophic failures that cause fish kills, sewer
dissolution, or other tragic occurrences. These are almost
always caused by gross malfunctions detectable by smell
or sight. Waste treatment control requires properly
trained operators to keep their eye and nose on the entire
operation. An operator who notices a yellow color in a
chromium reduction tank knows that he is not achieving
satisfactory chrome reduction regardless of what his
instrumentation shows. A strong smell of chlorine during
cyanide destruction indicates gross overchlorination or
chlorination at too low a pH. A nearly clear discharge to
the clarifier would indicate improper pH adjustment.
Too high a sludge blanket or floaters in a clarifier are a
sure sign of trouble. Incoming water for treatment
exhibiting an unusual color or turbidity will warn an alert
operator of potential danger.
pH Papers
Narrow range pH papers are a must for waste
treatment monitoring. They enable one to determine the
pH at any stage of waste treatment in less than 20 seconds
using less than S 10.00 worth of equipment, nothing
breakable, they are portable, and there is no clean up
after the test. They are extremely useful in process control
and in checking pH control meters.
Starch Iodide Papers
Potassium Iodide/ Starch indicator papers are
invaluable aids in monitoring alkaline chlorination of
cyanide effluents. They are the only control necessary for
batch chlorination and are useful for monitoring the
performance of ORP controls on flow through systems.
Test Kits
Two companies have made outstanding contributions
to waste treatment control by developing test kits for
analyzing waste waters and process waters. They are:
Hach Chemical Company; Ames, Iowa 50010 and
LaMotte Chemical Company; Chestertown, Maryland
21620. Both of these companies sell a variety of testing
equipment ranging from simple color comparative tests
costing about $20.00 for each parameter to be measured,
to elaborate spectrophotometric kits costing SSOO.OO to
$1,000.00. Generally speaking, we found these test kits
useful for process control and rough monitoring when
co-ordinated to a specific waste. The cheapest, most
simple ones are the most useful and that when it comes to
the elaborate ones one would be better off buying
conventional non-packaged equipment.
Test kits are extremely useful for waste treatment
control-
(a) when used as recommended by the supplier,
(b) when used as recommended by the supplier but
corrected to an approximate value using a correction
factor determined experimentally, and
(c) when used as recommended by the supplier on
samples which have been given more extensive
preparation than recommended by the supplier.
Test kits are formulated to compensate for
interferences experienced in a wide variety of wastes. For
many plating and printed circuit wastes, test kits will give
precise results when used as recommended by the
supplier. This can be checked out by performing a few
analyses on your waste and comparing the results to
those obtained using more precise methods.
If a wide discrepancy between test kit results and
precise analytical measurements is found, all is not lost.
In most instances where the test kits were not precise, the
results were repeatable and were off by a uniform
predictable value. If this is true for your effluent, a test kit
can be used by applying a correction factor for your
specific effluent. For example, a company we worked
with was having considerable trouble controlling
cyanide. Part of the problem was that a precise cyanide
analysis required 1 Vi to 4 hours and the services of a
skilled laboratory technician. By using a Hach test for
cyanide they were able to make a cyanide determination
in 20 minutes, using plating department personnel. They
found that for their effluent a Hach reading of 1.3 mg/1
cyanide corresponded to 2.0 cyanide amenable to
chlorination and a Hach reading of 4.5 mg/1 cyanide
corresponded to 10 mg/1 total cyanide.
An alternate to a correction factor can be to pre-treat
the sample to eliminate the interfering material.
Especially for metal analyses, acidifying the sample with
nitric acid and digesting for '/$ to 2 hours may destroy the
interferring element and enable one to use the test kit
satisfactorily.
The suppliers of the test kits will often help you on this.
Just as a warning, don't expect to win a court case
bused on test kit data if the opposition has used
"Standard Methods." In case of a fish kill or citation by a
regulatory authority, the test kit results will not stand up
unless you have well documented correlation between
such results and results obtained using "Standard
Methods." Even then, the only value the test kit results
will have is to show good faith on your part, rather than
to prove compliance.
Specific Ion Electrode
The specific ion electrodes have almost no value as
tools for monitoring waste treatment systems. Discharge
regulations relate to total pollutant and this varies widely
from ion concentration. Ion concentration depends on
temperature, pH. other materials present.
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Acceptable Analytical Techniques
Three "bibles" are available which describe the best,
most precise, universally accepted methods of analy/ing
waste waters. They arc: "Standard Methods for the
Examination of Water and Wastewater," published by
American Public Health Association; "Annual Book of
ASTM Standards." Water, Part 31; and "Methods of
Chemical Analysis for Water and Wastes," the
Environmental Protection Agency. Most of the
procedures in these three books are either identical or
very similar. Early regulations specified that the tests
were to be to "Standard Methods." The U. S. EPA now
reference their method of analysis, and the ASTM
Standards perhaps have the highest industrial
acceptance. An analysis conducted to the procedures in
any of these three books will be admissable as court
evidence. However, as a political decision, it is smart to
determine, when possible, what method is being used by
the regulatory authority you report to and then using the
same method.
In order to understand principles of analysis and to
develop the skills within your laboratory, I think it is wise
to study the procedures for a specific analysis in all three
books. ASTM goes into greater detail in describing
potential interferences and how to off-set them.
Generally speaking, ASTM also gives a greater number
of test options. "Standard Methods" is similar to ASTM
in their advising how to avoid pitfalls. Such information
is useful not only in developing skills and conducting the
analyses but are useful if you are trying to adapt Hach or
LaMotte test kits to your specific situation. The U. S.
EPA methods of analyses tend to be more dogmatic, but
it is simpler for most technicians to follow. U. S. EPA has
a companion manual entitled, "Analytical Quality
Control." This book is most useful for keeping an
analytical laboratory from wandering and becoming
imprecise.
The U. S. I:PA furnishes a very useful tool to waste
water control labs to aid in their quality control. The
Environmental Monitoring and Support l.ab..
Environmental Research Center, Cincinnati. Ohio
4526X, will furnish vials of prepared solutions containing
precise amounts of contaminants and a code sheet stating
the amount of these contaminants. The person in charge
of lab quality control can give these vials to the chemists
or technicians for analysis and when the results are
obtained they can be compared to the correct answer
furnished by the EPA. These cross checks go a long way
towards keeping everyone on their toes.
Periodic Impartial Sampling, Analysis
The effect of citations (fines, bad feelings) can be
minimi/ed by having periodic sampling and analyses
performed by an impartial outside laboratory. A hearing
officer will be inclined to be lenient if a company can
show consistent compliance prior to and after a \ iolation.
This system also keeps the waste treatment system
operator on his toes.
To sum it all up, for control the most easily conducted
test that will suffice should be used. These tests should be
done very frequently, perhaps 3 to 4 times a shift.
certainly, at least once a day. To verify conformancc to
regulations, to establish the validity of sample tests, and
for all data to be published in the literature, the testing
should be done in conformance with "Standard
Methods." "ASTM Standards," or. the "U. S. EPA
Methods" by an independent laboratory exercising rigid
quality control.
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Evaluation of Solvent Degreaser Emissions
Vishnu S. Katari, P.E., Richard W. Gerstle, P.E. and Charles H. Darvin
INTRODUCTION
Volatile organic compounds (VOC) are emitted from a
number of man made and natural sources. Typical
among the natural sources are volatile tupentine from
trees which are common in a number of wilderness areas
such as the Blue Ridge Mountains of Virginia. Nature in
her own way can accommodate and assimilate these VOC
emissions. On the other hand, man made VOC emissions
frequently represent a quantity which nature may have
trouble tolerating. One result of VOC emissions is
demonstrated graphically in the form of smog typical to
many of our larger cities. It has been estimated that the
total nationwide emissions of man made VOC is
approximately 28 million metric tons (31 million tons)
per year. Of this quantity, approximately 950,000 metric
tons (1,045,000 tons) per year comes from some form of
solvent degreasing operations.
Solvent metal cleaning can be divided into three main
categories: cold cleaning, conveyorized vapor degreasing
and open top vapor degreasing. This research and
development program evaluates practical and relatively
simple methods of significantly reducing organic solvent
emissions rates from open top vapor degreasing systems.
Even though this research evaluation program is still in
process, this paper has been prepared and presented to
indicate interim results. A final report will be prepared
and published at the completion of this study; it will
address the results of this study in detail.
BACKGROUND
There have been for a number of years solvent emission
control techniques that can recover or eliminate solvent
emissions from degreasing units. They include the use of
carbon adsorption or incineration. Carbon adsorption is
the process of removing molecules from an emission
stream by contacting them with activated carbon.
Incineration is the process of thermal destruction of
organic molecules. The feasibility of these processes
depends on plant economics and fuel availability.
Due to the potential economic impact that the use of
incineration or carbon adsorption may impart,
particularly on small job shop operations, this research
program was initiated by the Metals and Inorganic
Chemicals Branch of the Industrial Environmental
Research Laboratory. The program was designed to
•Vishnu S. Katari. P.E. & Richard W. Gerstle, P.E.
PEDCo Environmental, Inc.
Charles H. Darvin
U. S. EPA. Cincinnati, OH 45268
evaluate the capability of less expensive, although,
possibly less efficient concepts of control of VOC
emissions from vapor degreasers. Therefore, it is
believed that the Metals and Inorganic Chemicals Branch
through this research and evaluation program can make
a significant contribution to both industry and the goals
of EPA in identifying cost-effective and efficient VOC
control techniques for solvent degreasers.
A number of EPA and industry studies have identified
possible options for this purpose. Limited
experimentation has indicated that the use of such
options as increased freeboard heights, automatically
sealed tops, and/or secondary condensers could
significantly reduce the rate of organic emissions from
degreasers. A secondary advantage of these options
would be that they would not require major changes in
plant operation or equipment. Thus, they could provide
an inexpensive, simple-to-operate method of reducing
solvent emissions from degreasers.
Although previous studies have indicated solvent
savings, to date, no detailed quantification of the savings
potential of these concepts has been documented.
Therefore, to determine definitively the capability of
these techniques, a controlled test program was initiated.
The ASTM committee D-26 on degreasing was requested
to assist the testing contractor, PEDCo Environmental,
Inc., of Cincinnati, and EPA in defining and formulating
this test program. A special sub-committee of D-26 was
established for this purpose. Over 25 manufacturers of
degreasing systems, solvents, and users were contacted
for advice and support of the program. In addition,
representatives from NIOSH and OS HA were contacted.
Thus, influential groups that are involved in solvent
degreasing regulation, specification and utilization were
contacted for their comments and assistance.
TEST PROGRAM
A review of the typical vapor degreasers and their
design features, and recommendations from previous
studies led to selection of the following significant
variables for evaluation in this test series:
1) Cover utilization
2) Freeboard height
3) Refrigerated chiller (secondary condenser)
4) Lip exhaust
5) Hoist system speed
6) Load cross-sectional area
7) Solvent type
138
-------
Cover
Tank covers are an integral part of most vapor
degreasers and are used to cover the vapor zone when
idling or shut down. Many covers are left open and not
used. The amount of solvent that can be saved by utilizing
covers will be measured in this program.
Freeboard Height
Freeboard height is the distance from the top of the
vapor zone to the top of the degreaser tank. The primary
purpose of the freeboard is to reduce air movement near
the interface between air and solvent vapor. The
Occupational Safety and Health Administration
(OSHA) currently requires a freeboard-height-to-
degreaser width ratio of at least 0.50 or 91 cm (36 inches),
freeboard height whichever is shorter, for all vapor
degreasing tanks with a condenser or vapor level
thermostat. OS HA also requires a ratio of 0.75 when the
solvent is methylene chloride or trichlorofluoroethane.
Past studies reported a 27 percent reduction in solvent
emissions in an area of undisturbed air by increasing the
freeboard-to-width ratio from 0.50 to 0.75. A 55 percent
emission reduction was measured in turbulent air area by
increasing the ratio to l.O.2
Refrigerated Chiller (Secondary Condenser)
All vapor degreasers have a primary condenser which
utilizes cooling water to control the vapor height. Two
types of chillers are currently used above the primary
condenser for additional or secondary cooling; one
operates at sub-zero temperature of-23 to-32° C(-10to-
25° F) range and the other operates at I to 4° C (34 - 40°
F) range. The primary purpose of these chillers is to
reduce the rate of solvent loss from the top of the
degreaser.
Previous tests on a open vapor degreaser with the
subzero chiller using methylene chloride showed 40 to 43
percent solvent emission reduction.2
Exhaust
A lip vent exhaust can control the ambient air vapor
concentration around a degreaser by pulling the air and
vapor from the top of the degreaser. However, this may
increase solvent consumption unless a solvent recovery
system is used. One of the test degreasers will be used to
collect data on solvent emissions at exhaust rates of
approximately 15.2 to 30.5 m/min (50 and 100 ft/min)
face velocity.
Hoist System Speed
In degreaser operation a load is lowered and removed
by a vertical hoist system. The vertical movement of the
load into the degreaser generates a pumping or piston
action and increases emission rates by displacing the
vapor blanket. The current recommended maximum
hoist speed is 3.35 m/min (II ft/min.). The testing is
conducted at hoist speeds of 2.44 m/min (8 ft/min) and
4.88 m/min (16 ft/min) to determine the difference in
solvent consumption.
Load Cross-Sectional Area
The ratio of the load cross-sectional area to the
degreaser opening area is an important operating factor
affecting solvent consumption because of the pumping
action produced by the load movement. The
recommended maximum ratio of areas is 0.50 when using
many typical solvents. Solvent consumption is being
compared at load to degreaser top open area ratios of
0.50 and 0.70.
Solvent
Many different solvents are used in industrial vapor
degreasers. Because solvent characteristics such as
density, boiling point, and vapor pressure can interact
with other variables to generate unpredictable emissions,
this program will test at least two common solvents under
various operating conditions.
Methylene chloride and 1,1,1-trichloroethane are
being used in this test series. Grease deposits that melt
only at high temperatures may require a solvent with a
high boiling point such as trichlorothane [68° C (165° F)
boiling point]. To clean metals sensitive to temperature,
methylene chloride [40° C (104° F) boiling point] or
trichlorotrifluoroethane [47° C (117° F) boiling point]
would be a likely choice. Energy considerations also
favor solvents with a low boiling point.
DEGREASER SYSTEMS AND TEST FACILITY
In the beginning of the program, three options were
available for testing:
I) Equip a mobile testing facility for on-site testing of
degreasers during operation,
2) Use equipment now set up for testing at various
degreaser manufacturing facilities, or
3) Borrow degreasing equipment from manufacturers
and ship them to PEDCo's test laboratory.
After carefully considering these options, it was
decided to design a test facility and borrow the degreasers
from manufacturers. This option enhances the ability to
accurately monitor solvent emissions, and to better
control the test variables and operating conditions.
Several major manufacturers of vapor degreasers were
contacted in regard to design features of their systems
and some degreaser systems were examined at the
manufacturer's facilities. Basic designs do not vary
greatly. Only a few manufacturers make degreasers of all
sizes and types, and can supply most of the market
requirements. The others limit their production either to
a particular type (e.g., ultrasonic systems) or a particular
size [e.g., small 0.6 by 0.6 m (2-by 2-ft) units]. All provide
a cover, a definite freeboard height, and a system of
primary condenser coils. Typically, the degreaser unit is
also equipped with secondary condenser coils
(refrigeration chiller).
Three degreasers were selected: Degreaser A is
equipped with an above-freezing temperature secondary
condenser system and can be modified for variable
freeboard heights. Degreaser B is equipped with a below-
freezing temperature secondary condenser system and
can be modified for variable freeboard heights.
139
-------
Degreaser C is a small unit sized fora freeboard-to-width
ratio of 75 percent. Degreasers A and B are of typical size
[ 1.5 m long, 76 to 91 cm wide, and 76 to 91 cm freeboard
height (60 in. long, 30 to 36 in. wide, and 30 to 36 in.
freeboard height)], with vapor space dimensions which
are most frequently used for industrial vapor degreasing,
especially in small job shops and metal-working shops.
The test facility is designed with heating and air-
conditioning systems to maintain constant ambient
conditions of temperature and humidity. Currently
degreasers A and B are located in place side by side.
Necessary utility connections are in place and tests are
being conducted.
DEGREASER TEST PLAN
Table I presents the test plan designed to develop
quantitative relations between different design variables
and solvent losses. The test plan consists of two phases.
During Phase I the effects of selected variables on solvent
consumption and the interaction between variables will
be determined using 1,1,1-trichloroethane. During Phase
II, most of the Phase I experiments will be repeated while
using methylene chloride. These two solvents are selected
because the properties of each are'extremely different.
The results of tests will be analyzed to establish the
relationships between freeboard height, load cross-
TABLE 1
EXPERIMENTAL PLAN
:hlorethanc
•£
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u
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ylene chloride
•5 •
u
=
<
du
Degreaser A
Test No.
1
2
3
5 /
/
~/~
/
2
Exp. No.
IA
2A
3A
4A
5A
6A
7A
8A
9A
IOA
HA
I2A /
I3A /
I4A/
ISA
/
/
I6A
I7A
ISA
I9A
20A
2IA
22A
23A
24A
25A
26A
27A
Description
Idle test, cover open
Idle test, cover closed
Covering during operation
Variables:1
FB = 50/.J«%
SC = pn/off
A = JO/70%
yXsft/min
/"
/
Variables:
V = 16 ft/min
FB = 50/I25%
A = 50/70%
SC = off
Variables:
FB = 75 100%
V = 8 ft/min
SC = off
Variables:
FB = SO/ 125%
SC = on /off
A = 50/70%
V = 8 ft/min
Variables:
FB = 75%
A = 50%
V = 8 ft/min
SC = off
Exhaust = 50/100 ft/min
/ Degreaser B
Tesi No.
/
1
2
4
5
1
3
Exp. No.
IB
2B
3B
4B
SB
6B
7B
SB
9B
IOB
IIB
I2B
I3B
14B
I5B
I6B
I7B
I8B
I9B
20B
2IB
22B
23B
24B
2SB
26B
Idle test, cover open
Idle test, cover closed
No covering in operation
Variables:
FB = 50/I25%
SC = on/off
A = 50/70%
V = 8 ft/min
Variables:
FB = 75/ 100%
V = 8/16 ft/min
A = 50%
SC = off
Variables:
Small degreaser"
FB = 75%
V = 8 ft/min
A = 50%
SC = off
Variables:
FB = 50/I25%
SC = on/off
A = 50/70%
V = 8 ft/min*
Cross-current test
' FB- Freeboard height.
SC— Secondary condenser.
A- Load cross-sectional area.
V— Hoist speed.
h Small degreaser will be used for this experiment.
140
-------
sectional area, refrigeration freeboard chiller, hoist
speed, and degreaser size.
DEGREASER OPERATION
During the tests the degreasers are operated
continuously under different conditions for a preset time
period for each experiment. All experiments in this test
program are run for 24 hours to determine any significant
differences in solvent consumption at each level of a
variable being tested. During this time period, the load is
cleaned continuously over a preset cycle. Scales with a
113.4g (0.2S pound) precision are used to measure the
total solvent consumption. Thus for a 9Kg (20-pound)
loss in solvent, a maximum error of 1.25 percent could
occur. The error limit becomes smaller with higher
solvent consumption rates and longer experimental
periods.
A well defined clean load consisting of an extra heavy
wall black iron pipe coil, 8.5m (28 feet) long and
weighing 45.4 Kg (100 pounds), is used for each
degreaser. The load is placed on a perforated metal sheet
placed in a 22.6 Kg (50 pound) basket. To decrease cycle
time, the load is designed to be rapidly water cooled after
each degreasing cycle.
During the experimental period for most of the tests,
the load is operated continuously. During operation so
far, typical cycle time has been about 6.5 minutes. Table 2
presents an approximate cycle time distribution.
Parameters that are measured periodically during each
test are solvent consumption, solvent concentration over
the degreaser, temperature, humidity, air flow, and
barometric pressure. Cooling water rates and
temperature, and electrical consumption are also
measured periodically during the test. Solvent
consumption is the most important parameter because
the effect of design and operating variables will be
compared to consumption.
TEST RESULTS
Tests conducted so far have been run to determine the
effect of freeboard height, load area, and the utilization
of covers on solvent emissions. Figures 1 to 5 present the
results in terms of emission rate from the two degreasers
A and B. These tests were conducted over 8 to 24 hour
periods without secondary chillers and using 1,1,1-
trichloroethane solvent. The load was cleaned
30
TABLE 2
TYPICAL CYCLE TIME DISTRIBUTION
Time Interval
30 seconds
3 minutes & 30 seconds
30 seconds
20 seconds
60 seconds
IS seconds
25 seconds
Action
load descent
load cleaning
load ascent
pause
load cooling
air flushing of load
pause
25
20
§
%
5
10
5-
EMISSIONS REDUCTION,
FROM ©TO ©-81
FROM® TO®-54
)HEAT ON, NO COVER
)HEAT OFF, NO COVER
)HEAT OFF, COVER ON
NOTE: FB-50I
Fig. 1—Emissions from Idling degrtSMr.
60
50
40
30
20
10
©
sot
TEST CONDITIONS
HOIST SPEED - 8 ft/m1n
PRIMARY CHILLER - ON
SECONDARY CHILLER - OFF
LOAD SIZE (A) - 50X RATIO OF LOAD
TO DEGREASER CROSS- -
SECTIONAL AREA
EMISSIONS REDUCTIONS; X
FROMffiTO®: 29.5
FROM®TO®: 50.5
75t
lOOt
FREEBOARD (FB) HEIGHT
Fig. 2—Solvsnt •missions from dtgrtasar at different freeboard htlghts
and load sit* (A) at SO percent ratio.
141
-------
BU
70
60
50
•o
.0
c/? 40
0
t/>
•—I
LU
30
20
10
0
"~
-
-
T
50%
EST CONDITIONS
HOIST SPEED - 8 ft/m1n
PRIMARY CHILLER- ON
SECONDARY CHILLER-OFF
LOAD SIZE (A) - 70%
RATIO OF LOAD TO -
DEGREASER CROSS-
SECTIONAL AREA
EMISSl
FRC
IONS REDUCTION, %.
)M®TO(Z)- 28
125%
-
-
™
-
-
FREEBOARD (FB) HEIGHT
Fig. 3—Solvent emissions from degreaser at different freeboard heights
and load size (A) at 70 percent ratio.
continuously (6.5 minutes per cycle) at a hoist speed of
2.6m (8 feet per minute).
Figure I presents data on solvent loss from an idling
degreaser with a freeboard height of 50 percent. Covering
the degreaser top decreased the solvent emissions by 54
percent when no heat was applied. Boiling solvent in an
open top degreaser with no cover increased emissions by
81 percent.
Figure 2 and 3 show the effectiveness of increased
freeboard height on degreasers cleaning normal size (50%
area ratio) and oversize load (70% area ratio),
-
CD
50'.
(2)
7K
.
-
TEST CONDITIONS
HOIST SPEED - 8 ft/Bin
PRIMARY CHILLER - ON
SECONDARY CHILLER - OFF
FREEBOARD HEIGHT - 50V RATIO OF
DEGREASER WIDTH
- 38
LOAD SIZE
Fig. 4—Effect of load size on degreaser emissions.
respectively. The degreaser cleaning normal size loads
emitted about 30 percent less solvent when the freeboard
height increased from SO to 75 percent, and about SO
percent less solvent when the freeboard height doubled
from 50 to 100 percent of degreaser width. The degreaser
cleaning oversize loads emitted about 29 percent less
solvent when the freeboard height increased from 50 to
125 percent.
As shown in Figure 4, oversize load cleaning increased
emissions by 38 percent at a 50 percent freeboard height.
Figure 5 is an indication of cover usage on emission
rates. However, the data may not represent the
effectiveness of cover usage. During the tests on the
degreaser with no cover, the load was cleaned
continuously, but the other degreaser was kept closed
with periodic opening every half hour for one load
cleaning. The net result was the total amount of work
cleaned during the later test was only 30 percent of that
cleaned with the open degreasers. Thus, emissions on a
unit of load cleaned basis were actually less with the cover
off.
CONCLUSIONS
Test data produced thus far indicate substantial
savings in solvent usage with increased freeboard heights
and with load size that does not exceed 50 percent of the
degreaser open area.
Figure 6 presents solvent cost savings from degreasers
cleaning normal size loads. An increase of freeboard
height from 50 to 75 percent resulted in solvent savings of
142
-------
60
50
40
CO
o
to
to
30
20
10
TEST CONDITIONS
HOIST SPEED - 8 ft/m1n.
PRIMARY CHILLER - ON
SECONDARY CHILLER - OFF
FREEBOARD HEIGHT - 50%
RATIO OF DEGREASER-
WIDTH
3) COVER WAS OPEN
THROUGHOUT THE TEST
DCOVER WAS ON FOR 1/2
HOUR BETWEEN EAC"H '
CYCLE
EMISSIONS REDUCTION, %
FROM
-------
S4.83 per day and an increase from 50 to 100 percent
resulted in savings of S8.72 per day.
As shown in Figure 7, oversize load cleaning resulted in
additional costs of $6.23 per day. The degreaser required
a 125 percent freeboard height to off-set the additional
cost due to oversize load cleaning.
The results indicate that cleaning a normal size load in
a degreaser using increased freeboard height is more
economical as shown in Figure 8.
REFERENCES
1. Emission Standards and Engineering Division,
Chemical and Petroleum Branch, U. S. EPA. Control
of volatile organic emissions from organic solvent
metal cleaning operations (draft document). Research
Triangle Park, North Carolina, April 1977.
2. The Dow Chemical Company. Study to Support New
Source Performance Standards for Solvent Metal
Cleaning Operations. EPA Contract No. 68-02-1329.
U. S. Environmental Protection Agency, April 30;
1976.
144
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/8-79-011*
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Second Conference on Advanced Pollution Control for
the Metal Finishing Industry
5. REPORT DATE
June 1979 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Metals and Inorganic Chemicals Branch
Industrial Environmental Research Laboratory
Cincinnati, OH 1*5268
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Lab-Cinti, OH
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, OH 1*5268
13. TYPE OF REPORT AND PERIOD COVERED
Conference Proceedings Feb 79
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
Additional Sponsor: The American Electroplaters1 Society (AES)
16. ABSTRACT
Subject report contains technical research papers given at the Second Conference on
Advanced Pollution Control for the Metal Finishing Industry. This conference was
held in February, 1979 and was co-sponsored by the USEPA and the American Electro-
platers' Society (AES). Report contains papers on lERL-Ci research efforts and
covers all facets of air, water, and solid waste pollution control.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Industrial Wastes, Wastewaters, Metal
Finishing, Metal Coatings, Evaporators,
Air Pollution, Water Pollution,
Electroplating, Degreasing
Metal Preparation,
Metals, Reverse Osmosis
Solid Waste, Water Reuse,
Water Recycle, Toxic
68A
68C
68D
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
151
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
&U.S.GOVFJINIIIENT PRINTING OFFICE: 1979-657-060/1660 Region No. 5-11
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