Reclamation of Cleaning Water Using Ultrafiltration and Double Pass Reverse Osmosis

Abstract

In the production of electrodeposition primers, water is used as the primary cleaning agent. The dirty water that is generated contains residual contaminants from the primer production equipment, which requires that the water be disposed of as a hazardous waste. These contaminants are typically pigments and solvents. Because of the commitment to minimize process generated wastes, an integrated ultrafiltration (UF) and reverse osmosis (RO) system was installed to reclaim the cleaning water at the PPG Industries, Inc. (PPG) Cleveland, Ohio plant. The recovered water is then reused for cleaning in the primer manufacturing process. The integrated ultrafiltration and reverse osmosis system operates to reclaim 80 to 85% of the cleaning water. The system effectively removes 100% of the pigments and resins and 98% of the solvents and heavy metals. The quality of the final reclaimed water at the end of the process actually meets local sanitary water system discharge limits.