Case Study - KIA E-Coat Wastewater and Treatment Process
KIA Automotive uses a water-borne Electrodepostion (E-Coat) paint process that produces various wastes including rinse waters containing Zinc (Zn), Nickel (Ni) & phosphorous (P) waste. Most of the waste is found in the rinse waters from the e-coat overflows that contain less 1000 mg/l TSS. Some of the “dumps” contain detactified paint waste concentrate in small quantities. The various combinations of the waste create a unique treatment challenge. At the Equalization Tank (EQ Tank) the various wastewater streams are blended and homogenized into a predictable and consistent influent. Treatment is accomplished by use of a physical/chemical process; i.e., raising the pH of the wastewater to the minimum solubility of the combined metals, Zn, Ni, P, and, then, adding coagulants and a flocculant(s) to enhance settling of the solids. The separation of the solids from the clean water is accomplished by use of a large inclined plate clarifier. Solids settle into a cone type hopper and the effluent overflows to a multi-media filter for further polishing. pH is again adjusted to permitted discharge levels, usually less then 9, and the water is discharged to the city sewer or optionally recycled for internal use.