POLLUTION PREVENTION TECHNIQUES FOR ELECTRONICS AND COMPUTER INDUSTRY -------------------------------------------------------------------- The electronics and computer industries have participated in many pollution prevention projects and have been the focus of many case studies. Pollution prevention techniques and processes used by these industries can be grouped into four general categories: . Process or equipment modification . Raw material substitution or elimination . Waste segregation/separation/preparation . Recycling Each of these categories is briefly discussed below. Refer to section I for a list of specific pollution prevention techniques and associated costs, savings, and other information. Process or equipment modification is used to reduce the amount of waste generated. For example, manufacturers can change equipment or processes to: enhance water conservation by installation of countercurrent rinsing systems; reduce alkaline and acid concentration in tanks by installing a pH controller; and reduce drag-out by decreasing the withdrawal rate of parts from plating tanks. Raw material substitution or elimination is the replacement of existing raw materials with other materials that produce less waste, or a non- toxic waste. Examples include substituting non-cyanide solution for a sodium cyanide solution in copper plating baths and replacing hexava- lent chromium with trivalent chrome plating system. Waste segregation/separation/preparation involves avoiding the mixture of different types of wastes and avoiding the mixture of hazardous wastes with non-hazardous wastes. This makes the recovery of hazardous wastes easier by minimizing the number of different hazardous consti- tuents in a given waste stream. Also, it prevents the contamination of non-hazardous wastes. A specific example is segregation of wastewater sludge by metal contaminants. Recycling is the use or reuse of a waste as an ingredient or feedstock in the production process on-site. Examples of recycling include: recovering copper during the etching processes, recovering lead and tin from printed wiring boards, and installing a closed-loop recycling system to reuse freon (which is being phased-out) and reduce/reuse water consumption. I. POLLUTION PREVENTION TECHNIQUES FOR ELECTRONICS AND COMPUTER INDUSTRY This section provides examples of pollution prevention techniques used in the electronics/computer industry. I.I Examples of Source Reduction and Recycling Options for Electroplating Operations --------------------------------------------------------------- Technique - Process or Equipment Modification Option 1 - Modyfy rinsing methods to control drag-out by: . Increasing bath temperature . Decreasing withdrawal rate of parts from plating bath . Decreasing drip time over solution tanks; racking parts to avoid cupping solution within part cavities. . Shaking, vibrating, or passing the parts through an air knife, angling drain boards between tanks . Using wetting agents to decrease surface tension in tank. Contact: Braun Intertec Environmental, Inc., and MN Office of Waste Management (612) 649-5750. Option 2- Utilize water conservation methods including: . Flow restrictors on flowing rinses . Counter current rinsing systems . Fog or spray rinsing . Reactive rinsing . Purified or softened water . Dead rinses . Conductivity controllers . Agitation to assure adequate rinsing and homogeneity in rinse tank . Flow control valves. Contact: Braun Intertec Environmental, Inc., and MN Office of Waste Management (612) 649-5750. Option 3 - Implement counter flow rinsing and cascade rinsing systems to conserve consumption of water. Costs and Savings: Costs: $75,000 to upgrade existing equipment and purchasing new and used equipment. Waste Savings/Reduction: reduce water use and Environmental Quality (800) 452-4011. Option 4 - Use drip bars to reduce drag-out. Costs and Savings: Capital Investment: $100/tank. Savings: $600/year. Contact: NC Department of Natural Resources & Community Development, Gary Hunt (919) 733-7015. Option 5 - Use drain boards between tanks to reduce generations of drag-out. Costs and Savings: Capital Investment: $25/tank. Savings: $450/year. Contact: NC Department of Natural Resources & Community Development, Gary Hunt (919) 733-7015. Option 6 - Install racking to reduce generations of drag-out. Costs and Savings: Capital Investment: zero dollars. Operating Costs: Capital Investment: $100/tank. Savings: $600/year. Contact: NC Department of Natural Resources & Community Development, Gary Hunt (919) 733-7015. Option 7 - Employ drag our recovery tanks to reduce generations of drag-out. Costs and Savings: Capital Investment: $500/tank, Savings: $4,700/year. Contact: NC Department of Natural Resources & Community Development, Gary Hunt (919) 733-7015. Option 8 - Install counter-current rinsing operation to reduce water consumption. Costs and Savings: Capital Investment: $1,800-2,300. No direct costs. Savings: $1,350/year. Waste Savings/Reductions: reduce water use by 90-99%. Contact: NC Department of Natural Resources & Community Development, Gary Hunt (919) 733-7015. Option 9 - Redesign rinse tank to reduce water conservation. Costs and Savings: Capital Investment: $100. No direct costs. Savings: $750/year. Contact: NC Department of Natural Resources & Community Development, Gary Hunt (919) 733-7015. Option 10 - Increase parts drainage time to reduce drag-out. Contact: City of Los Angeles Hazardous and Toxic Material Project; Board of Public Works (213) 237-1209. Option 11 - Regenerate plating bath by activated carbon filtration to remove built up organic contaminants. Costs and Savings: Capital Investment: $9,973/year. Savings: $122,420/year. Waste Savings/ Reduction: 10,800 gallons/year. Reduce volume of plating baths disposed and requirements for virgin chemicals. Contact: EPA hazardous Waste Engineering Research Laboratory, Cincinnati, OH, Harry Freeman. Option 12 - Install pH controller to reduce the alkaline and acid concentrations in tanks. Contact: Securus, Inc., DBA Hubbard Enterprises. Option 13 - Install atmospheric evaporator to reduce metal concen- trations. Contact: Securus, Inc., BDA Hubbard Enterprises. Option 14 - Install process (e.g., CALFRAN) to reduce pressure to vaporize what at cooler temperatures and recycle water by condensing the vaapors in another container, thus concentrating and precipitating solutes out. Costs and Savings: Waste Savings/Reduction: reduce volume and quantity of aqueous waste solutions by recovering pure water. Contact: CALFRAN International, Inc., (413) 525-4957. Option 15 - Use reactive rinsing and multiple drag-out baths. Costs and Savings: Savings: Reduce cost of treating spent process baths and rinsewaters. Waste Savings/Reduction: increase lifetime of process baths and reduce the quantity or rinsewater requiring treatment. Contact: SAIC, Edward R, Saltzberg. Option 16 - Improve control of water level in rinse tanks, improve sludge separation, and enhance recycling of supernatant to the process by aerating the sludge. Costs and Savings: Savings: $2,000/years. Waste Savings/Reduction: reduce sludge generation by 32%. Contact: NJ Hazardous Waste Facilities Siting Commission, Hazardous Waste Source Reduction and Recycling Task Force. Option 17 - Install system (e.g., Low Solid Fluxer) that applies flux to printed wiring boards, leaving little residue and eliminates the need for cleaning CFCs. Costs and Savings: Waste Savings/ Reduction: reduce CFC emissions over 50%. Contact: AT&T Bell Laboratories, Princeton, NJ. Option 18 - Install ion exchange system to reduce generation of drag- out. Costs and Savings: Savings: $1,900/year. Capital Investment: $78,000. Operating Costs: $3,200/year. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 19 - Employ reverse osmosis system to reduce generation of drag-out. Costs and Savings: Savings: $40,000/Year. Capital Invest- ment: $62,000. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 20 - Use electrolytic metal recovery to reduce generation of drag-out. Costs and Savings: Capital Investment: $1,000. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 21 - Utilize electrodialysis to reduce generation of drag-out. Cost and Savings: Capital Investment: $50,000. Contact: NC Department Of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 22 - Implement evaporative recovery to reduce generation of drag-out. Costs and Savings: Capital Investment: $50,000. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 23 - Implement the electrodialysis reversal process for metal salts in wastewater. Costs and Savings: Savings: $40,100/year in operating costs. Contact: Ionics, Inc., Separations Technology Division. Technique - Raw Material Substitution Option 1 - Substitute cyanide plating solutions with alkaline zinc, acid zinc, acid sulfate copper, pyrophosphate copper, alkaline copper, alkaline copper, copper fluoborate, electroless nickel, ammonium silver, halide silver, methanesulfonate-potassium iodide silver, amino or thio complex silver, no free cyanide silver, cadmium chlo- ride, cadmium sulfate, cadmium fluoborate, cadmium perchlorate, gold sulfite, and cobalt gold. Contact: Braun Intertec Environmental, Inc. and MN Office of Waste Management (612) 649-5750. Option 2 - Substitute sodium bisulfite and sulfuric acid for ferrous sulfate in order to oxidize chromic acid wastes, and substitute gaseous chlorine for liquid chlorine in order to reduce cyanide reduction. Costs and Savings: Savings: $300,000/year. Waste Savings/ Reduction: reduces feedstock by 50%. Contact: Eastside Plating and OP Department of Environemntal Quality (800) 452-4011. Option 3 - Replace hexavalent chromium with trivalent chromium plating systems. Contact: City of Los Angeles Hazardous and Toxic Meterial Project; Board of Public Works (213) 237-1209. Option 4 - Replace cyanide with non-cyanide baths. Contact: City of Los Angeles Hazardous and Toxic Material Project; Board of Public Works (213) 237-1209. Option 5 - Replace conventional chelating agents such as tartarates, phosphates, EDTA, and ammonia with sodium sulfides and iron sulfates in removing metal from rinse water which reduces the amount of waste generated from precipitation of metals from aqueous wastestreams. Costs and Savings: Costs: $178,830/year. Savings: $382,995/year. Waste Savings/Reduction: 496 tons of sludge/year. Contact: Tyndall Air Force Base, FL, Charles Carpenter (904) 283-2942; EG & G, Dan Sucia, Penny Wilcoff, & John Beller (208) 526-1149. Option 6 - Replace methylene chloride, 1,1,1-trichloroethane, and perchloroethylene (solvent-based photochemical coatings) with aqueous base coating of 1% sodium carbonate. Costs and Savings: Waste Savings/ Reduction: reduce solvent use by 60 tons/year. Contact: American Etching and Manufacturing, Pacoima, CA. Option 7 - Replace methanol with nonflammable alkaline cleaners. Costs and Savings: Waste Savings/Reduction: eliminate 32 tons/year of flammable methyl alcohol. Contact: Amercian Etching and Manufacturing, Pacoima, CA. Option 8 - Substitute a non-cyanide for a sodium cyanide solution used in copper plating baths. Costs and Savings; Waste Savings/Reduction: reduce 7,630 pounds/year. Contact: Highland Plating Company, Los Angeles, CA. Technique - Recycling Option 1 - Send drag-out waste to another company for waste exchange. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 2 - Reuse rinsse water. Costs and Savings: $1,500/year. Capital Investment: $340/tank. No direct costs. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 3 - Reuse drag-out waste back into process tank. Contact: NC Department of Natural Resources & Community Development; Pollution Prevention Pays Program Gary Hunt (919) 733-7015. Option 4 - Recovery process chemicals with fog rinsing parts over plating bath. Contact: City of Los Angeles Hazardous and Toxic Mate- rial Project; Board of Public Works (213) 237-1209. Option 5- Evaporate and concentrate rinse baths for recycling. Contact: City of Los Angeles Hazardous and Toxic Materials Project; Board of Public Works (213) 237-1209. Option 6 - Use ion exchange and electrowinning, reverse osmosis, and thermal bonding when possible. Contact: City of Los Angeles Hazardous and Toxic Material Project; Board of Public Works (213) 237-1209. Options 7 - Use sludge slagging techniques to extract and recycle metals. Costs and Savings: Capital Investment: $80,000 for 80 tons/ year and $400,000 for 1,000 tons/year. Operating Costs: $18,000 per year for and 80 ton facility. Waste Savings/Reduction: reduce volume of waste by 94%. Contact: City of Los Angeles Hazardous and Toxic Material Project; Board of Public Works (213) 237-1209. Option 8 - Use hydrometallurgical processes to extract metals from sludge. Contact: City of Los Angeles Hazardous and Toxic Material Project; Board of Public Works (213) 237-1209. Option 9 - Convert sludge to smelter feed. Contact: City of Los Angeles Hazardous and Toxic Material Project; Board of Public Works (213) 237-1209. Option 10 - Remove and recover lead and tin from boards by elect- rolysis or chemical precipitation. Contact: Control Data Corporation and MN Office of Waste Management (612) 649-5750. Option 11 - Install a closed loop batch treatment system for rinse- water to reduce water use and waste volume. Costs and Savings: Savings: $58,460/year. Capital Investment: $210,000. Waste savings/ Reduction: 40,000 gallons/year (40%). Contact: Pioneer Metal Finishing, Inc., Harry Desoi (609) 694-0400. Option 12 - Install an electrolytic cell which recovers 92 percent of dissolved copper in drag-out rinses and atmospheric evaporator to recover 95 percent of chromatic acid dragout, and recycle it into chromic acid etch line. Contact: Digital Equipment Corporation and Lancy International Consulting Firm, William McLay (412) 452-9360. Option 13 - Oxidize cyanide and remove metallic copper to reduce metal concentrations. Contact: Securus, Inc., DBA Hubbard Enterprises. I.2. Examples of Source Reduction and Recycling Options for Etching Operations ------------------------------------------------------------------------ Technique - Raw Material Substitution Option 1 - Substitute sodium persulfate etchant (acid etch solution) with hydrogen peroxide/sulfuric acid. Contact: ADC Products and MnTAP (612) 625-4949. Technique - Recycling Option 1 - recover copper by electrolytic processes. Contact: ADC Products and MnTAP (612) 625-4949. I.3. Examples of Source Reduction and Recycling Options for Semiconductor Manufacturing ------------------------------------------------------------------ Technique - Process or Equipment Modification Option 1 - Install a system (e.g., the CALFRAN process) to reduce pressure to vaporize water at cooler temperatures, recycle water by condensing the vapors in another container, and concentrate and pre- cipitate solutes. Costs and Savings: Waste Savings/Reduction: reduce volume and quantity of aqueous waste solutions by recovering pure water. Contact: CALFRAN International, Inc. Springfield, MA 01101, Val Partyka (413) 525-4957. Option 2 - Reduce chrome waste generation by : . Installing a rain cover over on outdoor tanks to reduce chrome waste . Treating on-site with caustics and sodium bisulfite to reduce chrome VI liquid to chrome III sludge . Repairing water leaks in process rinse tank to reduce chrome waste. Costs and Savings: Capital Investment: #30,000 for the rain cover, pipe repairs, and on-site treatment system. Waste Savings/Reduction: Savings: $15,000/year in disposal costs, and reduce 95% of chrome wastes from 6,000 gallons to two or three drums generated per quarter. Contact: Wacker Siltronic Corporation and University of MN (612) 625-4949. Technique - Raw Material Substitution Option 1 - Replace chlorinated solvent baths with a non-hazardous product to reduce, and later, eliminate use of chlorinated solvents. Costs and Savings: Waste Savings/Reduction: reduce chlorinated solvent use by 93%, and then completely eliminate the use of the chemical. Contact: Wacker Siltronic Corporation and University of MN (612) 625-4949. Technique - Recycling Option 1 - Convert an open-top still into a closed loop system to recycle Freon 113. Costs and Savings: Cost: $20,000. Waste Savings/ Reduction: $57,000/year in disposal and feedstock costs, and reduce waste volume by 85%. Contact: Wacker Siltronic Corporation and University of MN (612) 625-4949. Option 2 - Use Athens system to reprocess sulfuric acid generated during wafer fabrication operations. The acid is heated to boil of water and other impurities, purified through distillation, and pumped back into wet stations to continue wafer processing. Costs and savings: Annual savings/Reductions: $2.9 million from not purchasing sulfuric acid and 28% reduction in sulfuric acid generated in 1993. Contact: intel or Alameda Instruments, Inc. and Athens Corporation (Manufacturers of this type of equipment). I.4. Examples of Source Reduction and Recycling Options for Printed Wiring Board Manufacturing ----------------------------------------------------------- I.4.a. General Operations -------------------------- Technique - Process or Equipment Modification Option 1 - Modify sludge pretreatment processes by: . Adding flow control valves . Installing metal recovery equipment . Adding of deionization system Costs and Savings: Costs: lower chemical treatment costs. Waste Savings/Reduction: $90,000 in disposal costs. Contact: Unisys Corpo- ration and MnTAP (612) 625-4949. Option 2 - Redesign board during board assembly. Contact: Capsule Envr\ironmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. Option 3 - Install a system (e.g., CALFRAN process) to reduce pressure to vaporize water at cooler temperatures, recycle water by condensing the vapors in another container, concentrate and precipitate solutes. Costs and Savings: Waste Savings/Reduction: reduce volume and quantity of aqueous waste solutions by recovering pure water. Contact: CALFRAN International, Inc. Springfield, MA 01101, Val Partyka (413) 525-4957. Option 4 - Alternatives to wet chemicla processes include: . Mechanical cleaning as an alternative to chemical methods; . Process efficiency improvements for applying photopolymers, printing, and developing; . Alternative processes for connecting the PWB layers together; and . Alternatives to lead-based soldering involving the use of lasers, reactive gases, or ultrasonics. Contact: EPA CST. Technique - Raw Material Substitution Option 1 - Substitute semiaqueous or aqueous photoresist for TCA and methylene chloride during board manufacturing. Contact: Capsule Environmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. Option 2 - Substitute no-clean fluxes for CFC 113 and TCA during board assembly. Contact: Capsule Environmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. Option 3 - Substitute aqueous clean fluxes for CFC 113 and TCA during board assembly. Contact: Capsule Environmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. Option 4 - Substitute semi-aqueous cleaning materials for CFC 113 and TCA during board assembly. Contact: Capsule Environmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. Option 5 - Substitute other solvents for CFC 113 and TCA during board assembly. Contact: Capsule Environmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. Technique - Waste Segregation/Separation/Preparation Option 1 - Segregate wastewater sludge to prepare for metal recovery. Contact: Unisys Corporation and MnTAP (612) 625-4949. Technique - Recycling Option 1 - Remove and recover lead and tin from boards by electroly- sis-chemical precipitation. Contact: Control Data Corporation and MN Office of Waste Management (612) 649-5750. I.4.b. Cleaning Operations -------------------------- Technique - Prrocess or Equipment Modification Option 1 - Install a system (e.g., Low Solids Fluxer (LSF) which applies flux to printed wiring boards, leaves little residue, and eliminates the need for cleaning with CFCs. Costs and Savings: Waste Savings/Reduction: reduce CFC emissions over 50%. Contact: AT&T Bell Laboratories, Princeton, NJ. Technique - Raw Material Substitution Option 1 - Substitute for CFC 113 used in defluxing with: . Fully aqueous system using water soluble fluxes . Aqueous system using saponifiers to remove rosin based fluxes . Semi-aqueous system using terpenes as a solvent . Hydrogenated CFCs with chlorinated solvents Contact : Medronic Inc. and MN Technical Assistance Program (MnTAP) (612) 627-4848 Maria Scheller. Option 2 - Substitute CFC 113 used in hand cleaning boards with: . Blend of HCFC and methanol dispensed from a trigger-grip device that limits the amount of solvent lost to the atmosphere Contact: Medtronic Inc. and MN Technical Assistance Program (MnTAP) (612) 627-4848 Maria Scheller. I.4.c. Electroplating Operations ---------------------------------- Technique - Raw Material Substitution Option 1 - During tin-lead electroplating process, substitute fluo- boric acid with: . Organic sulfonic acid (OSA) plating . Acid tin sulfate plating which eliminates lead use . Hot air leveling . Conductive, solderable polymer solutions Contact: Capsule Environmental Engineering Inc. and MN Office of Waste Management (612) 649-5750. I.5. Examples of Source Reduction and Recycling Options for Cathode Ray Tube Manufacturing ------------------------------------------------------------------ Technique - Process or Equipment Modification Option 1 - Reduce building of contamination in bath solutions by in- creasing process efficiency (e.g., implement ion exhcange technology). Contact: EPA CSI. Technique - Raw Material Substitution Option 1 - Replace lacquer in panel preparation with a wax-like material similar to floor wax. It provides the necessary coating without a high VOC content. One potential drawback, however, is the use of ammonia. Contact: EPA CSI. Option 2 - Replace Freon as a cleaning agent for removing particulate contaminants from panel mask frames with air blow cleaning and an aqueous wash (nearly all CRT manufacturers have implemented this change). CPA CSI. Option 3 - Identify less hazardous cleaning chemicals, such as isop- ropyl alcohol, as alternatives to acetone or chlorinated solvents in maintenance and cleanup processes. Contact: EPA CSI. Option 4 - Find substitutes for chromium-based photoresists. Contact: EPA CSI. Option 5 - Identify alternatives to the lead-based frit used in sea- ling the funnel with the panel mask. Constact: EPA CSI. Technique - Recycling Option 1 - Regenerate acids for glass cleaning and frit removal in waste glass recovery operations using existing technologies and equip- ment. Contact: EPA CSI. Option 2 - Reclaim and reuse photoresists from one of the panel pre- paration processes. Contact: EPA CSI. Option 3 - Recover soluble lead generated during the waste glass recovery operation by ion exchange resins. Reuse in lead smelting ope- rations. Contact: EPA CSI. Option 4 - Improve phosphor solution r ecovery and recycling effici- encies to further reduce discharge of metals to the environment. Contact: EPA CSI. Option 5 - Reduce or recover the following: . Chrome wastes . Cleaning materials (hydrofluoric acids) . EP effluent . Furnaces slag . Cullent dust . Fugitive dust . Refractory brick wastes . Alcohols Contact: EPA CSI. SOURCE : CTEM PUBLICATION DATE : 15TH JUNE, 1999