Metal Finishing Pollution Prevention:
EPA Region 9 and Arizona Department of Environmental Quality (ADEQ) implemented a metal finishing P2 program in South Phoenix, AZ. The program focused on a wide range of subjects transferable to many facilities. Costs, raw material savings, and waste reductions were documented for each project. Detailed descriptions of the projects are documented in the following fact sheets: http://www.epa.gov/region9/waste/p2/projects/metal.html
- Reverse osmosis applications for metal finishers PDF (4 pp, 199K)
- Innovative cooling system for hard chrome electroplating PDF (1 pg, 1.13M)
- Modifying tank layouts to improve process efficiency PDF (4 pp, 337K)
- Reducing rinse water use with electrodeless conductivity control systems PDF (4 pp, 385K)
- Reducing dragout with spray rinses PDF (4 pp, 404K)
- Finding an alternative to solvent degreasing PDF (4 pp, 168K)
- Metal recovery and wastewater reduction through electrowinning PDF (4 pp, 186K)
- Extending electrodeless nickel bath life with electrodialysis PDF (4 pp, 106K)
- Metal finishing bath life extension PDF (4 pp, 263K)
This information is also available through the National Metal Finishing Resource Center (NMFRC). The sample outlines of the workshops used in the Metal Finishing P2 Project are located at: http://www.epa.gov/region9/waste/p2/projects/wkshops.html
Pollution Prevention for the Electroplating and Metal Finishing Industry Covers pollution prevention strategies for the metal finishing industry, which can be used to minimize the generation and release of wastes. Information regarding alternative technologies, regulatory requirements, and case studies is included: http://www.sbeap.org/publications/pp4elecro_metal.pdf
Metal Finishers and Electroplaters: Regulatory Requirements and Pollution Prevention Ideas A summary of the preventative measures and technologies the metal finishing industry can implement to reduce pollution in the workplace. Also details many of the environmental regulations associated with the metal finishing industry. Located at: http://www.sbeap.org/TrainingTools.php?type=Training%20tool,manual,Checklist
Alternative For: Acid neutralization, filtration, and landfill deposition
Adsorption Treatment System To Recover Mineral Acid Solutions The adsorption treatment system uses an ion exchange process to recover spent acids from waste acid streams, such as those associated with electroplating processes. Upon recovery, the wastewater is released to a treatment plant. Ion exchange is a chemical reaction where an ion from solution is exchanged for an oppositely charged ion attached to an immobile solid particle, i.e., an ion exchange resin. Ion exchange reactions are stoichiometric and reversible. The use of an adsorption treatment system can help facilities meet pretreatment standards for discharges of wastewater to a publicly owned treatment plant (40 CFR 403) or meet effluent limits of a NPDES permit (40 CFR 122). In addition, this treatment process may help facilities meet the requirements of waste reduction under RCRA, 40 CFR 262, Appendix.
Alternative For: Solvent-Borne Painting, Spray Painting
Electrocoating Electrocoating reduces or eliminates volatile organic compounds (VOCs), hazardous air pollutants (HAPs), and the generation of hazardous waste associated with conventional solvent spray application. The reduction or elimination of VOCs and HAPs may allow a facility to avoid regulation under the National Emission Standards for Hazardous Air Pollutants (NESHAPs) and/or related air pollution regulations at the federal, state, and local levels, including requirements under the Clean Air Act Title V Operating Permit Program.
Alternative For: Hazardous waste generation and the associated disposal costs
Electrodialysis Technology For Anodizing Bath Solutions The addition of an electrodialysis unit to an anodizing bath system can extend the useful life of the bath solutions and thereby significantly reduce the volume of hazardous waste generated. Electrodialysis does not affect the anodizing process. It is simply a process that can indefinitely extend the useful life of the bath solution by maintaining a low concentration of metal ions. The capture media, catholyte, removes the metal ions and forms a concentrated sludge.
Alternative For: Hazardous waste generation and the associated disposal costs
Electroless Nickel Bath Life Extension (Archived) Utilizing Electroless Nickel (EN) bath life extension technology to augment current EN operations can increase the life of a plating bath at a typical naval facility up to ten-fold, reduce the volume of hazardous waste generated by up to 90 percent, and reduce the associated disposal costs.
The reduction of hazardous waste helps facilities meet the requirements of waste reduction under RCRA, and may also help facilities reduce their generator status and lessen the amount of regulations (i.e., recordkeeping, reporting, inspections, transportation, accumulation time, emergency prevention and preparedness, emergency response) they are required to comply with.
Alternative For: Wastewater disposal, conventional end-of-pipe treatment
Electrolytic Recovery Technology For Metal Cyanide Recycling Electrolytic recovery technology uses an electrical current to plate out the metals and oxidize the cyanides in the rinse waters from electroplating. The metal is recovered from the electrolytic recovery unit (ERU) as a foil that can be returned to the cyanide plating bath as an anode source. Electrolytic recovery technology can remove more than 90 percent of the metal in the rinse stream and oxidize up to 50 percent of the cyanides thus reducing the use of hazardous chemicals including acids, alkalis and chlorine-containing chemicals to treat rinse waters. Additionally, since the metal is recovered the volume of metal-containing hazardous sludge at the wastewater treatment plant is reduced.
This technology generates a less contaminated rinse water and thereby reduces the amount of treatment chemicals used by a treatment facility. Because less chemicals are used the possibility that a treatment facility would meet any of the reporting thresholds of SARA Title III (40 CFR 300, 355, 370, and 372) and EO 12856 is decreased.
Alternative For: Hard Chrome Plating
High Velocity Oxy-Fuel Thermal Spray High Velocity Oxy-Fuel (HVOF) thermal spray technology is a dry process that produces a dense metal coating whose desired physical properties are equal to or surpass those of hard chrome plating (HCP). These properties include wear resistance, corrosion resistance, low oxide content, low stress, low porosity, and high bonding strength to the base metal.
This process melts a metal powder and produces a dense metallic coating with physical properties are equal to or surpassing those of HCP. The only waste stream produced by HVOF is from the capture of the overspray. Since the overspray contains only the pure metal or alloy, it is feasible to recycle or reclaim this waste stream. Traditional plating operations generate a large volume of hazardous waste from contaminated plating bath solutions and rinse waters.
Alternative For: Electroplated hard chromium (EHC) plating and other plating processes
Ion Implantation Process Ion implantation is a potential enhancement method for chrome plating or other plating processes, as well as a process that can improve engineering properties of substrate materials. Therefore, any site using electrolytic hard chrome plating or other plating processes could be a candidate for implementation, as could original equipment manufacturers to improve the service life of components such that refurbishment would not be necessary until a much longer service period has passed.
Alternative For: Cyanide Based Nickel Stripping Processes
Non-Cyanide Nickel Strippers Until recently, the majority of stripping of metal coatings from production parts has been accomplished using cyanide based processes. The disadvantages of cyanide-based stripping are that cyanides are hazardous to personnel, require frequent bath solution change-outs due to a limited bath life, and generate rinse streams containing high concentrations of metals and cyanides.
Non-cyanide based metal stripping removes metal based coatings from production parts by dipping the parts in a bath solution, and rinsing. Using a non-cyanide based metal stripping process reduces the volume of hazardous waste generated and the associated disposal costs, and exposure of personnel to hazardous materials and wastes.
Alternative For: Cyanide Silver Plating
Non-Cyanide Silver Plating Non-cyanide silver plating deposits a silver coating to production parts by dipping the parts in a bath solution, and rinsing. Using a non-cyanide plating process reduces the volume of hazardous waste generated and the associated disposal costs, and exposure of personnel to hazardous materials and wastes.
Until recently, the majority of silver plating of production parts has been accomplished using cyanide-based processes. The disadvantages of cyanide-based plating are that cyanides are hazardous to personnel; require frequent bath solution change-outs due to limited bath life, and the generation of rinse streams containing high concentrations of metals and cyanides. The rinse water generated requires pre-treatment to remove the cyanides and metals at the Industrial Wastewater Treatment Plant before the water can be released to the Public Owned Treatment Works (POTW). The treatment process at the treatment plant requires the use of toxic chemicals such as sulfuric acid, caustic, chlorine, and other hazardous materials.
Alternative For: Chemical removal; mechanical abrasion with abrasive burr or wheel; heat sources, such as lasers or soldering irons
Precision Micro-Abrasive Sand Blasting For Cleaning Circuit Boards Micro-abrasive sand blasting is accomplished by propelling a finely graded abrasive powder into a stream of compressed air, through an abrasive-resistant hose and out a miniature nozzle manually or automatically positioned at the workpiece. The process is used to remove a variety of conformal coatings, including epoxy, acrylic, urethane, silicone, parylene, and ultraviolet-cured materials, from printed circuit boards for rework and repair. It replaces chemical, mechanical, and thermal methods of coating removal. Some micro-abrasive units also can be used for other functions, such as deburring, texturing, drilling, and cutting.
Alternative For: Chromic Acid Anodizing (CAA)
Sulfuric/Boric Acid Anodizing The Sulfuric/Boric Acid Anodizing (SBAA) process is a direct replacement for the Chromic Acid Anodizing (CAA) process used on aluminum production pieces. The SBAA process consists of a sulfuric/boric acid anodizing bath and a chromate sealer bath. SBAA is a commercially available and tested process that provides a protective coating meeting all military and industrial specifications applicable to the CAA process. The SBAA process was tested by the Naval Air Systems Command (NAVAIRSYSCOM) at NADEP North Island and has been approved by NAVAIRSYSCOM as an alternative to the CAA process.
Alternative For: Certain Electroplating processes like cadmium
Surface Coating By Physical Vapor Deposition PVD is a desirable alternative to electroplating and possibly some painting applications because it generates less hazardous waste and uses less hazardous materials (i.e., no plating baths). Physical Vapor Deposition (PVD) comprises a group of surface coating technologies used for decorative coating, tool coating, and other equipment coating applications. It is fundamentally a vaporization coating process in which the basic mechanism is an atom by atom transfer of material from the solid phase to the vapor phase and back to the solid phase, gradually building a film on the surface to be coated. In the case of reactive deposition, the depositing material reacts with a gaseous environment of co-deposited material to form a film of compound material, such as a nitride, oxide, carbide or carbonitride.
Alternative For: Certain Electroplating processes like cadmium
Zinc-Nickel Plating Used for replacement of cadmium coatings (applied by electrodeposition, typically from a cyanide-based plating bath). The reflectalloy alkaline zinc-nickel plating process is a direct replacement of the cadmium process used on fasteners and steel components to provide protection against corrosion.
The purpose of this overview is to present the results of a feasibility study that has led to Department of Toxic Substances Control (DTSC) decision to develop a specific Pollution Prevention (P2) program that targets Hexavalent Chrome (Cr-6) and Cyanide waste streams in the metal plating and finishing industry throughout California. See: http://www.dtsc.ca.gov/PollutionPrevention/SB1916/upload/ppac-metal-plating-report.pdf
Aircraft Maintenance Chromium Replacement. This project identified the best alternatives to chromic acid anodizing (a common inorganic pretreatment for aluminum) from existing and developmental methods.
Enhanced Surface Coatings By Ion-Plating The Construction Engineering Research Laboratory (CERL) is studying a more cost-effective way to prevent surface-initiated failures by simply depositing corrosion- or wear-resistant materials on the surface of susceptible structures.
Metal Finishers Fact Sheet Utah Department of Environmental Quality ,
More than 31,000 metal finishing facilities in the United States generate hazardous waste from their production processes. Pollution prevention and reducing hazardous waste generation can save money and reduce future liability
Environmental Assistance Division, Michigan Department of Environmental Quality
Thermal spraying is a process in which metals are melted and sprayed on a surface to form a coating. Other names for thermal spraying include flame spraying, metallizing, and hardfacing.
Brimac Anodizing P2 Case Study
West-Tech Finishing Inc., P2 Case Study
Metalon Technology Ltd. , P2 case Study
DeCaro Manufacturing, P2 case Study
Pollution Prevention at Specific Plating Company Specific Plating has dramatically reduced its sewer discharges of copper and nickel. The company’s pollution prevention efforts include both modifications of industrial processes and improved waste handling and treatment techniques.
Valley Chrome Plating Case Study. With encouragement of the California Department of Toxic Substances Control, Valley Chrome became one of the first sizeable decorative plating firms in the U.S. to abandon carcinogenic hexavalent chrome in its manufacturing process and switch to less toxic trivalent chrome. http://www.dtsc.ca.gov/PollutionPrevention/MFMS/Metal_Finishing_Success.cfm
Definitions of the Seven Core Environmental Goals – National Metal Finishing Strategic Goals Program – (April 10, 2009) ,
National Metal Finishing Strategic Goals Program Online – provides an overview of the pollution prevention goals for water reduction, energy reduction, reduction of hazardous waste, reduction of metals emissions, increased metals utilization, reduction of organic TRI emissions, and reduction in human exposure to toxic material – percentage goals have been established and methods for meeting the goals are outlined.
Environmental Management Systems: A Guide for Metal Finishers – NSF International supported by US EPA, Office of Research and Development This project involved 11 metal finishing companies in a pilot project with the following objectives: 1) to demonstrate Environmental Management Systems (EMS) implementation in the metal finishing industry, and 2) to better define the resulting costs and benefits. The IS0 14001 (1996) Environmental Management Systems Standard was used as the basis for defining an environmental management system.
Guide to Pollution Prevention Practices: Benchmarking Metal Finishing – National Center for Manufacturing Sciences (NCMS) This feature presents a summary of pollution prevention strategies for common metal finishing processes. This information comes from the Benchmarking Metal Finishing, document prepared by the National Center for Manufacturing Sciences (NCMS).
Policy and Rules
Stormwater Rules Have Changed and Metal Finishers Must Take Action – National Metal Refinishing Resource Center Revised Stormwater regulations, referred to as Phase II Stormwater rules, were published by EPA in 1999. The Phase II rules have changed the “no exposure” option. If you do not meet the definition of “no exposure”, and if you do not have a stormwater permit, you are currently out of compliance.
Alternative Technologies for Surface Finishing – US EPA, Office of Pollution Prevention and Toxics ,
Several alternative surface finish technologies are available that can provide a planar mounting surface and do not use lead. They range from other metals such as nickel, tin, gold, and silver to organic-based coatings. Although many facilities use these alternative surface finishes, a comprehensive analysis has not been undertaken before to compare the performance, cost, and health and environmental risks associated with them. In response to industry interest for this information, the Design for the Environment (DfE) PWB Project undertook a comparative evaluation of health risk and competitiveness issues for HASL and five alternative surface finishes.
Capsule Report: Approaching Zero Discharge in Surface Finishing – US EPA, Office of Research and Development – (November 2000) This document provides technical guidance to surface finishers, environmental managers and decision makers on control technologies and process changes for approaching zero discharge (AZD). AZD is one of the key themes underlying the Strategic Goals Program (SGP), a cooperative effort among the U.S. Environmental Protection Agency (EPA), the American Electroplaters and Surface Finishers Society, the National Association of Metal Finishers, and the Metal Finishing Suppliers Association to test and promote innovative ideas for improved environmental management within the metal finishing industry.
Metal Finishing Industry Pollution Prevention Project – Eighth Progress Report – The Metal Finishing Pollution Prevention Task Force The Project goals are to develop a methodology and supporting tools for formulating pollution prevention (P2) plans for the reduction of toxic substances used, generated and/ or released in the metal finishing industry. The Project aims also to promote the development and implementation of site-specific pollution prevention plans by the members and member companies of Canadian Association of Metal Finishers and the American Electroplaters and Surface Finishers Association and to publish progress of substance use reduction under the plans.
Pollution Prevention for the Metals Finishing Industry – Northeast Waste Management Official’s Association (NEWMOA) The Northeast Waste Management Officials’ Association (NEWMOA) designed this online manual to provide environmental assistance staff with a basic reference on metal finishing. The purpose of the manual is to enable assistance providers to rely on a single publication to jump start their research on pollution prevention for metal finishers with whom they are working. The manual is explicitly designed to be useful to assistance professionals with experience working with metal platers and those who have never encountered metal finishing before. The U.S. Environmental Protection Agency Pollution Prevention Division funded this manual as a model of a comprehensive packet of information on a single industry.
Profile of the Metal Casting Industry – US EPA, Office of Compliance and Enforcement This link provides access to a web page that allows users to download this entire document or sections of interest. In addition, links are included to allow user to find updated data on this industry in the Sector Notebooks in order to obtain the most current emissions data from the Toxic Release Inventory (TRI) and compliance and enforcement data.
Profile of the Metal Fabrication Industry – US EPA, Office of Compliance and Enforcement
This link provides access to a web page that allows users to download this entire document or sections of interest. In addition, links are included to allow user to find updated data on this industry in the Sector Notebooks in order to obtain the most current emissions data from the Toxic Release Inventory (TRI) and compliance and enforcement data.
Replacement of Chromium Electroplating Using Advanced Material Technologies On Gas Turbine Engine Components – GE Aircraft Engines, Cincinnati, OH Electrolytic hard chrome plating (EHC) has been widely used by OEMs and the Department of Defense (DoD) weapon systems community in the sustainment of weapon systems’ performance. The overhaul of gas turbine engines at military depots is no exception. In general, HCAT has been finding that not only do cost effective alternatives for EHC exist, but they often result in improved performance which would warrant making the changes from EHC to the alternatives on technical merit alone.
Replacement of Chromium Electroplating Using HVOF Thermal Spray Coatings – Naval Research Laboratory Due to both environmental and life-cycle-cost issues, the Department of Defense has established a program to qualify HVOF thermal spray coatings as viable alternatives to hard chrome plating in aircraft maintenance. A Joint Test Protocol has been established to delineate the types of tests required to execute this qualification and successfully validate HVOF coatings for these types of operations. In this paper, the results of fatigue, corrosion, and abrasive wear tests for 83/17 WC/Co and Tribaloy 400 coatings deposited by HVOF are compared to those for hard chrome plating.