Pollution Prevention Opportunities in Metal Finishing
helpful information from
U.S. EPA Region III
Philadelphia, PA
Ooctober 1990
For More Information
National Association of Metal Finishing
III E. Walker Drive
Chicago, Illinois 60601
312-644-6610
....... & Surface Finishers
12644 R.... Parkway
Orlando. FL 32826
407-281-6441
US EPA Pollution Prevention Information Center
703-821-4800 (into)
703-506-1025 (Access)
Pollution Prevention in Metal Manufacturing
EPA/530-SW-89-056
703-821-4800
Waste Minimization Audit Report
Case Studies of Minimization of Cyanide Waste
From E Operations
EPA /600/S2-87/056
703-821-4800
Conbol and T....kw The MOW Industry: in Plant Changes
EPA/625/8-82-008
703-821-4800
MOW Control Alternatives
Control Costs in
EPA/625/.....
703-821-4800
mm I and
Manual for Om Metal Finishing
Industry Toxin Substances Control Program
California Dept. of Health Services
916-324-1807
Waste Minimization in Metal Parts Cleaning
EPA/530-SW-89-049
703-821-4800
What Can You Do?
This fact sheet lists specific pollution prevention practices that have been successful at a number of metal finishing plants. Use this fact sheet along with the "Pollution Prevention Opportunities" fact sheet to gather ideas on how to reduce your wastes.
Improve Operations
- Allow only trained workers to mix baths.
- Use sumps that are easy to clean.
- Separate used oils from other wastes.
Substitute Materials
- Use deionized water to reduce sludge production.
- Use less toxic plating solutions (zinc instead of cadmium; trivalent chromium instead of hexavalent chromium).
- Replace cyanide and barium salt baths with sulfate or chloride baths. Use alkaline cleaners instead of solvents.
- Use no-rinse coatings.
Extend Process Bath Life
- Use purer anodes, or regenerate plating solutions through filtration.
- Reduce drag-in by modified rinsing.
- Cover baths with lids when not in use to reduce evaporation.
- Test process baths to determine when additional chemicals should be added or contaminants removed.
- Design and maintain racks and barrels to reduce the build-up of water and maximize drainage.
Reduce Drag Out
- Lower the concentration of plating bath constituents; increase the plating solution temperature.
- Use non-ionic wetting agents to reduce solution surface tension.
- Withdraw workpieces at a slower rate to allow maximum drainage.
- Extend drip time; install drip racks.
- Install drainage boards between tanks to route dragout into the correct process tank.
- Install wringer rolls or air wipes at the exit from strip or wire plating tanks.
Reduce Rinse Water
- Install automatic flow controls.
- Install multiple rinse tanks in a counter-current series system.
- Use sprays or mist to rinse off excess process solutions.
- Agitate the rinsing bath to increase efficiency.
Reuse & Recycle
- Install dragout collection tanks.
- Send spent acid/alkaline solutions back to the manufacturer.
- Recover plating metals from sludge.
We Encourage you to Pursue Pollution Prevention Opportunities Within your Company. Be a Part of the Cultural Change.
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Last Updated: January 16, 1996