PROJECT SUMMARY
WASTE MINIMIZATION AUDIT REPORT
CASE STUDIES OF MINIMIZATION OF CYANIDE HASTE
FROM ELECTROPLATING OPERATIONS
by
Jacobs Engineering Group Inc*
Hazardous and Toxic Materials Division
Pasadena, California
Contract No.: 68-02-7053, HA »46
Project Officer
Harry Freeman
Thermal Destruction Branch
Alternative Technologies Division
HAZARDOUS HASTE ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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NOT tCE
This doc%aI ent has been reviewed In accordance with U.S. Environmental
Protection Agency policy and approved for publication. Mention of trade
names of comer ci&l products does not constitute endors ient or recomen—
dation for use.
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EXECUTIVE *4MARY
To promote waste minimization activities in accordance with the national policy
objectives established under the 1984 Hazardous and Solid Waste Amendments to the
Resource Conservation and Recovery Act of 1976 (RCRA), the Hazardous Waste
Engineering Research Laboratory (HWERL) of the USEPA Office of Research and
O.v.lopment h s undertaken a project to develop and teds waste minimization ( ‘ NM)
audit procedure.
As part of this project, a total of 6 WM audits were carried out In four separate
facilities. Thu report presents the results of the on-site WM audits performed at two
electroplating facilities that generate cyanide-bearing wastes. The report also
describes the WM audit procedure as it has developed from the initial (pre-project)
sequenc. of steps, to the modified (past-project) sequence that reflects the experience
gained during this HWERL project. The 4 other audits, 2 dealIng with solvent wastes
and 2 dealing with heavy metal and corrosives wastes, are discussed in two separate
reports.
LO• WAS1 MU UM ATION ALW PRO DURE
The main objective of this report Is to provide usaM guidelines far the conduct of a
‘NM audit. The following sections dIscuss how a WM audit fits Into en overall WM
program, and provide brief descriptions of the principal elements of a WM audit.
U The Role of the WM Audit in sWM Proar*m
The primary objective at a waste minimization program Is to reduce the quantity
and/or toxicity of waste effluints leaving the production process. The essential
elements of a WM program Include the initiation and planning of the program, the
planning end execution of a WM audit, and the implementation of the recommended
meaauree that emerge from the audit process.
During the program initiation phase, the commitment of tap management to reduce
waste generation must be estabLIshed, which results in the development of an
organizational structure for the WM program and in the setting of waste reduction
goals for the entire organization. The next step involves characterizatIon at waste
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generation rates and waste characteristics. The program planning step follows, with
the selection of the audit team(s) to carry aut the actual auditing phase. The auditing
process constitutes the most important element of the overall WM program, since it
provides the key Inputs for the generation of WM options, u well as for the decisions
of which waste minimization measures should be implemented. Following the audit,
selection of options for ImplementatIon are made besed on feasibility analysis. Finally
WM measures go through the sequence of design , procorement, construction, startup,
and performance monitoring.
1.2 Waste Minimization Audit Procedure
The execution of a waste minimization audit can be divided into three distinct phases,
as shown In Table 1. The overall objective of the pre .audIt phase Is to gather and
analyze the Information necessary to select a waste stream(s) for ths facility audit.
The audit phase follows, the objective of which Is to develop a comprehensive set of
WM options and to soreen them. The product of the audit phase is a list of option.
selected for further evaluation. A technical and economic feasibiUty analysts Is
performed for each selected option during the post-audit phase of the program. This
phase ends with th. preparation of a final report. The following paragraphs provide a
brief description of each audit step.
1. Preparation for h. audit
The objective of this step is to gain background Information about the facility to be
audited. Preparation should Includ, examination of Information sources related to the
processes, operations, and waste management practices at the facility. The result of
proper preparation should be a well-defined needs list, Inspection agenda, or a
checklist detailing what Is to be accomplished, what questions or ‘ ‘,s need to be
resolved, and whet Information needs to be gathered. The needs list should be
provided to the faculty before the actual site visit to allow the facility personnel to
assemble the m.teriala needed by the audit team in advance.
2. Pre-audlt meeting
The next step Is a pre-audit meeting with plant personnel. This initial contact should
include solicitation f plant personnels’ views on the focus and function of the audit.
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TASL.E 1 RECO 1B 1OED WASTE M UM1ZATION AL.CIT PROCEDURE
Program
Phase
Activities
Product
Pr.-Audlt
1.
PreparatIon for the audIt
a
needs list/inspection
agenda
2.
Pre-eudlt meeting and
inspection
a
notes
3.
Data compilation and
waste stream selection
o
facility and process
description
a
waste description
a
rational, for selection
Audit
4.
Facility InspectIon
a
notes
5.
Qinerstlon of a campre-
hensive t of WM options
a
list of proposed options
with written rationale
6.
OptIons evaluation
a
independent options ratings
by audit team and by -
plant personneL followed by
Joint review
7.
Selection of options for
fessiblUty analyses
o
a
list of selected options
options Interim report
Post-AudIt
8.
TechnIcal and economic
feasibility analysis
a
study or budget grade
estimates of capital and
operating cnsts profit-
ability analysis
9.
Final report preparation
a
final report with
recommendations
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The information needs identified in the previous step siiOUId be discussed. A tour of
the facility wu1d be performed to familiarize the audit team with the operations
performed. During this meeting, it Is important to estabI1& a key facility contact.
3. Data compilation and waste stream selection
Selecting the principal waste streams Or waste pro Jciflg operations f or the audit
provides th. audit team with the focus for th. effort. The criteria used far waste
stream selection includs waste composition, quantities, degree of hazard, method and
cost of disposal, perceived potential for minimization, and compliance status.
After all pertinent data are collected, they si ould be assembled In the form of a
written facility description. Th. description iouId Include facility Location and size,
description of pertinent operations or processes , and a description of th. waste
streams centering on sources, generation rates, and current methods of management.
The report mould includ, a writtan justification for selection of a waste stream(s) far
study.
4. AudIt Inspection
The audit Inspection Is the ultimate step In the information gathering process. The
governing objective of this step Is to evolve a fuller understanding of primary and
secondary causes of waste generation for the selected waste streams, and to cover the
items missed in the pre-eudit phase. The audit Inspection must result in a clear
understanding of waste generation causes. Useful guidelines for this step include
having a detailed inspection agenda ready In advance, scheduling the Inspection to
coincide with the particular operation that Is of interest, obtaining permission to
interview plant psracnnsl directly, obtaining permission to photograph the facility,
observing the “housekeepIrg aspects of operation, and assessing the level of
coordination of environmental activities between various departments.
5. GeneratIon of WM options
The objective of this step is to generate a comprehensive set of WM options. It is
important at this point to List as Large a number of options as possible, including WM
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,*ii.i 5. W’W S R1 TIOU OPTIOUS MIGTLlS? POP OTUIDS NU Sl ULICISOPL*TJ &TICSS
OPTIONS COS RNT S
Drag-out minimization - ly reducing dreg-out. lean of lb. plating solution saves th. tank.
Norkpiec. positioning - Proper po.itionliig at the part on th. rack r.diic.s solution drag-out.
Withdrawal speed sod drainage - Slow speed. r.disc. drag-out. Parts should be allowed to drain over tank.
Drag-out recovery - Drain board. nod drip tank. can be used so r.cover plating solutions.
Concentration - Reducing the concentration of the bath reduces lo..ss due to dug-out.
Tamp.ratur. - Increased temperatur, reduce. solution viscosity / surface tension.
Surfactants — Lower lb. surfac. tension of lb. solution which reduces drag-out.
latsasion of bath lit. - Isducss the frequency .1 spent bath replacement.
Drag-in reduction - If ticlsmt rinsing prevents cross-conts .inatio of solution..
Oslonizod water - Seduces the build-up at calcium end magnesium ions in lbs bath.
Japurity removal - Can he performed by chemical precipitation, freezing carbonates), or by
tllt.ring part iculatesi.
Rack maintenance - Corrosion sad .alt deposits on the rack can coptsain.ts plating bath..
hondas - Us. of purer anode. and bags will prevent insoluble impurities in the anodes
Ira. entering th . bath. nodee .bould be removed when not in use.
Return solution Hess manufacturer. of plating solution, will rsproc..u spent baths.
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Minimization of rinse water - Seducing flow promotes recovery of metals and makes treatment more effective.
£uto.stic Slow control - Reduce. water use while insuring required degree of rinsing.
agitation - Increases rinsing efficiency which reduces the volume of water needed.
Multipl. tanks - Count.r-curr.ot rinsing can reduce water requirements by SO to So percent.
Spray/Cog nozzles - Nor. efficient then rinsing a part in a tank at water.
Closed-loop rinsing - Suac.ptsble to impurity build-up and may require lbs use of a rscovery
system. e.g.. evaporation ion •mchangs. reveres osmosis. •l.ctrodialysis.
Mon-cyanide solutions - I limina tss the generation of a cyanide-bearing waste.
Copper plating - Pyrophoapbat. copper plating solution may be used as a r.p)sce.ent.
Cadmium plating - Substitute. Include cadmium tluoborat. sod acid sulfate cadmium bathe.
Silver stripping - Nay be performed with potassium nitrate and em.oaiua bydroside.
Liternate plating techniques - Ilimluat.. the use of basardou . plating solution..
Ion vapor dsposition - Can ho used to plate parts with cadmium or aluminum. Rsguir.d squipsant I.
very complea and .zp.nslve.
Good operating practices - Helps to minimize Masts generation through procedural policine.
Segregation - Proper segregation can prevent sizing of hazardous and non-hazardous waste.
Trslning/supcrviOlOn - Operator awarone.s can help identify sod eliminate wasteful practices.
Spill a d leak prevention - Seduce. lbs loss of materials and the g.neratlon of clean-up wastes.
Maintenance - Preventive and cqrrectlva maintenance reduces spills, leak. and upsets.
Material tracking/control - Provides lbS facility with accurate material balances sdiicb can be used to
identify and quantify material •od waste handling problems.
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measures currently in place in the audited facility. Option generation should follow a
hierarchy to reflect the environmental desirability of source reduction over recycling,
and of recycling over treatment. Options can be generated by examining the technical
literature, through discussion with manufacturers of equipment or suppliers of process
input materials, and through the use of a checklist. Table 2 provIdes a checklist
suitable for electroplatIng wastes.
6. Options evaluation
Each of the option. postulated In the preceding step must undergo a preliminary
qualitative evaluation. The objective of this evaluation is to weed out the measures
th*t do not merit additional consideration and to rank the remaining measures in the
order of their overall desirability. The evaluation should consider aspects such as
waste reduction effectiveness, extent of current use In th. facility, industrial
precedent, technical soundness, cod, effect on pro ct quality, effect on plant
operations, Implementation period, end implementation resources availability. It is
recommended that the evaluation process be performed independently by both the
audit team and the hod facility personnel. A rating system has been developed to
rank th. measures in a consistent pattern and to provide a framework far resolving the
differences In opinions.
7. SelectIon of options tar feasibility analysis
Following the evaluation process by the two independent grot a, the two sets of
ratings are compared and disou d in a joint meeting In orders to develop ratings which
are mutually acceptable. Ths product of this meeting is a WM options List with revised
ratings. Th. final ratings are than used as a basis for the selection of options for
additional feasibility analysis. The number of measures promoted to the feasibility
evaluation stage depends an the time, budget, and resources available for such study.
8. AnalysIs of technical and economic feasibility
The specific WM options selected f or additional evaluation must be analyzed. Study-
grade (e.g., 3a% accuracy) estimates for the capital and operating costs can be
obtained from preliminary vendor information or factored estimation techniques.
Once the cost.s are obtained, the analysis is focused on an estimation of profitability,
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based on conventional methods (payback period, internal rate of return, or net present
value).
9. Final report preparation
As the concluding step of a WM audit, a final report should be prepared tO summarize
all the pertinent data, results, and recommendations.
2.0 RE .LTS OF WASTE MThW A11CN ALC TS FOR CVA E WASTES
Waste minimization audits were conducted at two electroplating facilities generating
cyanide-bearing wastes. The following section. imm.ri e the reports prepared for
each facility.
2.1 Facility C-lA /B
Facility C-lA/B, located In Southern California, La a major aviation, industrial, and
se ort complex supporting anti-submarin, aircraft, helicopters, and aircraft carriers
of the P*ciflc Fleet. Cyanide wastee are generated from various operations associated
with the plating shop. The principal metals plated at this facility ate chromium,
nickel, aluminum, copper, cadmium, and silver.
Plating Ii performed using racks or barrels. The sequence at unit operations is very
similar for the plating of different type of metals and Includsi alkaline cleaning, acid
cleaning, stripping (If th. removal of old costing is, required), and eLectroplating.
Each operation 1* followed by a single flowing water m is.
The cyanide loss and subsequent waste stream generation is due to (a) drag-cut of
plating/stripping solutions, which enter the rinse water, and (b) plating solution
filtrate, which is retained In the filtering medium end dL os.d of as solid waste.
Owing to a high drag-cut rate, the solutions are replenished frequently and do riot have
to be replaced periodically. Out cf 650,000 galLon. of wastewater generated daily,
about 5 percent is estimated to originate from cyanide-based plating operations.
A total af 31 source reduction options were considered and grouped into six distinct
categories based on the similarity in end-result of the methods. The categories
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include drag-out minimization, bath life extension, rinse water minimization,
sibstitutlon of non-cyanide solutions, substitution of alternate plating metals or
techniques, and good operating practices. Each measure was then rated based on a
pre-establlshed rating system.
Through a Joint review of the ratings of each proposed waste minimization option by
the audit team and facUlty p.rs nneL, a 1st of high-ranking options was selected for
additional evaluation and analysis. Ths options chosen as candidates for further
analysis were reduction of drag-out using drain boards and extanslon of bath life
through impurity removal, reduction of dreg-cut using drain boards and extension of
bath life through conversion to mechanical agitation, recovery of drag-out using still
rinsing, reduction of water usage using spray rinsing, and ajbstitution of non-cyanide
cadmium plating solutions. Table 3 summarIzes the results obtained from the
economic feasibility study associated with these options.
A preliminary economic feasibility study was Independently performed for 5 waste
minimization options selected from among 31 options initially considered. Since the
payback periods calculated for thee. options did not exceed a rula-of-the-thumb”
3 year value, the options appear feasible and maybe considered for Implementation.
2.2 Facility C-2
Facility C-2 is a small shop located in Southern California whose main business Is
refinishing decorative Item .. The principal metals plated at this facility are nickel,
brass, silver, and gold.
The basic operations performed at the plating shop Include paint stripping, cleaning,
electroplating, drying, and polishing. All operations are performed manually.
Cyanide-bearing waste is generated from silver stripping, from silver, gold, brass, and
copper electroplating, and from the associated rinsing operations. The principal waste
streams include wastewater (e.g., overflows from the continuous rinse tanks and water
used for floor washings) and plating tank filter waste. Wastewaters from non-cyanide
sources such as paint stripping, buffing, and floor wishing, and from electroplating
operation are routed to a common sump. The contents of the sump (approximately
300-4CC gallons of sludge) are pumped out periodically arid disposed of as hazardous
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TABLE 3 SL 4MARY OF ECONOMIC FEAS LITY STUDY FOR FACLITY
Control
Category
Waste
Reduction
Method
Waste
Reduction
(%)
Capital
Cost
($)
Monthly
Cod
($!month)
Monthly
Savings
($!month)
Pay-back Period
(month)
1. Drag-out Use of drain boards 90 890 784 1.1
Minimization
Use of drain boards! 90 1103 1820 784
impurity removal
Ua of drain boards!
mechanical agItation 90 7030 784 9.0
Still rinsing
- Copper 40 560 202 2.8
- Cadmium 40 1680 58 2.4 yrs
- Silver 40 2800 89 2.6 yrs
gq 2. Bath Life impurity removal 213 1820
Extension
Mechanical agitation 6140
3. Rinse Water Spray rinsing 50 11685 440 2.2 yr.
Minimization
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waste. Owing to high dreg-out rate, plating Iutlans are adequately purged and thus
need riot be replaced on a periodic basis.
A total of 2J options were initially postulated far the reduction of cyanide-bearing
waste from the plating siiop. As was the case far facility C-lA/B, the WM options
were grouped Into six categarIe dreg-out minimization; bath life extension; rinse
water minimization; substitution of nm-cyanide solutions; good operating practices;
and plant layout alterations. Most of the proposed options era the same as those
proposed for facUlty C-lA/B, with th. exception of the options Involving good
operating practices and plant layout alteration (both are slt...specif I c m.aaur,e). The
options were rated by the project staff and were then presented to th. facility
personnel for review.
HIgh..rwflclng options were lacted far f.uibility evalu*tlon. These included
reduction of drag-out using drain boards, extension of bath life through the u of
deionized water, reduction of water usage using spray rinsing, end use of plastic media
blasting Instead at paint stripping (In conjunction with waste stream segregation).
TabLe 4 presents a summary of the rea4ta abtain d train the economic feasibility
study of these options.
A preliminary feuibtlity study was pert o id far 4 waste reduction options selected
from among 23 options initlafly considered. Of these tour optians, only spray rinsing
appears to be economically unvisbie. The other options appear feasible and may be
considered for future implementation.
3.0 0 RVATIONS A? RECOMP CAT!CNS
The foilowing observations and recommendations were made as the result of the pilot
aud its
a Fag’ th. two fa iUtjs audited, the availability of the required process
documentation was not satisfactory. Experience with these and other sites
indicated that the availability arid quality of the information varies
significantly. Much information is available, however, from outside
sources such as vendors, chemical suppliers, and literature.
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TABLE 4 SUMMARY OF ECONOMIC FEASIBILITY STLUY FOR FACLITY C-?
Percent
Description Waste Capital Monthly Monthly
of Reduction Cost Cost Savings Pay-back Period
Opleons Method (S) (5) (S/month) (5/month) (month)
1. Drag-out Lisa of drain boards 50 MS - ‘ 241 1.3
Minimization
2. Extensional Use of deionized 50 582 38 241 2.9
Bath L11e water
3. RInse water Use of spray rInsing 50 2,825 -- 29 0.1 years
Minimization
4. Good Operating Use of plastic medIa 90 17,900 2,519/yr 6,607/yr 4.4 years
Practices blasting
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‘Economic analysis was performed In conjunction with the Implementation of drain boards.
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o Pre-audit activities, particularly the pre-audlt site visits, were found to be
extremely Important in facilitating the audit process. Cooperation by the
plant staff was Improved when the audit teem went more time getting to
know the host faculty staff and how their organization functioned.
o ParticipatIon In the options ratings process Is much Improved when the host
facility personnel are required to independently develop ratings of each of
the WM options under consideration.
o Good operating practices recommendations must be presented with their
economic dimension stressed in order to retain th. interest of the host
facility personnel. Otherwise, they can be seen as trivial and trite.
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