Wastewater treatment for electrocoating

Solution from the paint tank continually undergoes ultra-filtration (UF) to prevent process contamination and produce final rinse makeup. Typically fronting the UF units are one or more bag filters of increasing filtering capabilities, which remove foreign particulates that have entered the paint bath. The detackified paint curd is separated from the liquid portion of the paint by a dedicated filter press or some other filtering device. The filter cake can be reduced in volume by further dewatering or evaporation. Proper handling of waste products created by the cleaning, pretreatment, and painting processes is an extremely important part of the entire electrocoating equation. Waste treatment strategies must focus on removing impurities from the system while retaining paint chemistry. Ultra-filtration is not considered a portion of the waste treatment system, although a small amount of paint will be removed from this closed loop when the bag filters are replaced. The bag filters are disposed of along with concentrated paint wastes.