Automotive Industry Wastewater Treatment

Automotive manufacturers use a water-borne electrodeposition (E-coat) paint process that produces wastes containing zinc (Zn), nickel (Ni), and phosphorus (P). Most waste is found in rinse water from E-coat overflows, which can contain less than 1,000 mg/L TSS. Some dumps contain detactified paint-waste concentrate in small quantities. Together, these streams create a unique treatment challenge.

At the equalization tank, wastewater streams are blended and homogenized. Treatment uses a physical and chemical process: the wastewater pH is raised to the minimum solubility of the combined metals, then coagulants and flocculants are added to improve settling. Solids are separated from clean water using a large inline plate clarifier. Solids settle into a cone-type hopper, while effluent flows to a multi-media filter for polishing. The pH is readjusted to permitted discharge levels before water is discharged to the city sewer or optionally recycled for internal use.