Cleaner Production in Metal Plating Industry

The Metal Plating Industry:
Improvement of Resource Efficiency and Environmental Performance

Metal plating is a subset of metal finishing and surface coating. Related industries include metal cleaning, painting and coating, and heat treating.

The tables below list low-cost or no-cost solutions to reduce waste and pollution in any metal plating company, including ones in developing countries. All of these ideas have been proven to help small companies, anywhere in the world, save money while protecting the environment. The PAMA should demonstrate that these options have been considered thoroughly. Direct links to online guides to metal plating pollution prevention follow the table.

Install spill containment	Spills can be contained and managed to prevent losses of valuable resources.
Lengthen dragout time	Allows more chemical to drip back to process tank, so reduces the amount of chemical introduced in rinsewater.
Establish dragout timing	Post dragout times on signs at tanks to remind employees. A drain time of at least 10 seconds has been demonstrated to reduce dragout by 40+%, compared to the three-second industry average.
Install drain boards or drip guards	Boards and guards minimize spillage between tanks and are sloped away from rinse tanks so dragout fluids drain back to plating tanks.
Use conductivity sensors	These sensors indicate the cleanliness of the rinsewater. They cost only a few hundred dollars to order, and can greatly improve plating quality and prevent unnecessary dumping of rinsewater.
Agitate rinse bath	Agitation promotes better rinsing. Agitate water or part manually or with mechanical means (stirring or air bubbling).
Reuse spent acid/alkaline	Spent acid can be used to neutralize an alkaline waste stream. Spent alkali can be used to neutralize an acid waste stream.
Evaporation	Concentrate rinsewater and captured dragout liquids for reuse; the water condensate can also be reused. Mechanical evaporators or simple boilers can be used.
Increase bath temperature	Evaporates bath water so relatively clean waste rinsewater can be reused as bath makeup water. Reduces solution viscosity so more chemical drains back to process tank during dragout. Do Not Use On Cyanide or Hexavalent Chromium Baths.
Optimize bath concentrations	Run tests with successively lower bath concentrations to find the minimum level needed to achieve quality. This saves money by reducing overuse of chemicals and reduces contamination in wastewater. Remember that concentrations recommended by vendors are usually higher than the minimum needed for quality.