WASTEWATER TREATMENT FOR ELECTROCOATING

Because it is an immersion process, electrocoating employs the use of a large amount of water. Typically, pigment, resin, and additives make up only 10 to 15% of the contents of an electrocoating paint tank. Electrocoating is also an extremely efficient coating process due to recycling of paint through ultrafiltration, with usage typically ranging from 95 to 99%; however, the small amount of paint, which may at some point elude deposition, must be extracted from the waste stream prior to discharge. Wastewater treatment strategies for electrocoating - like those for pretreatment stages - are based on three main considerations: (1) removing impurities from the process tanks; (2) retaining useful materials in the process tanks; (3) minimizing the impurities for disposal.