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ANODIZING AND
THE ENVIRONMENT
Anodizing's environmental friendliness and relative safety are
among its best properties, in the age of increasing concern for
human protection and quality of our land, water and air.
Anodizing uses simple water-based chemicals that can be treated
easily and that release no harmful by-products. The liquid
by-products are recycled and returned to the process. Solid
by-products can be isolated and diverted for use in the manufacture
of alum, baking powder, cosmetics, newsprint, fertilizer and water
purification systems. The U.S. Environmental Protection Agency,
which heavily regulates the production and use of solvent-based
paints and flouropolymer finishes containing volatile organic
compounds (VOCs), regards anodizing as an environmentally friendly
process.
Anodizing does create a by-product composed primarily of aluminum
hydroxide, some aluminum sulfate and water. It is harmless
because it contains no significant amounts of heavy metals. In some
cases, municipal sewerage treatment plants benefit from these
by-products by using them as filters in the secondary treatment of
sewage. | 
