Volatile organic compounds and malodors emitted from painting operations are of primary concern in the automotive industry and pressured to be abated by newly amended VOC rule and offensive odor law in Korea. Over-sprayed paints in painting booths are delivered into water surface by downward stream of clean air and collected in water circulating pools. The circulating water mixed with waste paints generated from paint booths put out floating sludge by addition of chemical killing agent and floating agent and the odors evolved from this procedure has been under the circumstance that it must be validated to match the new rules. The activated sludge method that the circulating water pond would be considered as a huge bioreactor was applied to this over-sprayed sludge tank. and we got some remarkable reductions of sludge, odours, VOCs and dirts on air dusts. Herein, some abbreviated results will be reported.