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 ------- 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. ii ------- 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 ------- 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. E-2 ------- 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 E - 3 ------- 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 E -4 ------- ,*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. i v ) 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. ------- 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, ------- 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 ------- 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 ------- 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 ------- 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. .10 ------- 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 4T1 ‘Economic analysis was performed In conjunction with the Implementation of drain boards. ------- 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. £-12 ------- |