Tap water was coagulated with polymeric Al chloride (PACl) and Al-2(SO4)(3) at 20 degrees C (Al dose 1,1-3,3 mg/L). The postcoagulation sludge was sepd. by sedimentation and recycled to the original water. Zeta potential was detd. before and after sludge addn. to the water sample. Humic acids-contaminated water (an artificial sample) was coagulated with PAC. The purifn. was followed by detn. of UV absorbance at 254 nm and turbidity. Recycling of the postcoagulation sludge resulted in decreasing the coagulant consumption.