Treatment of submerged hollow fiber ultrafiltration membrane for reuse of sludge water

To lower the costs of wastewater treatment, the submerged hollow fiber ultrafiltration membrane was employed to reuse the filter backwash water and settling tank sludge water. Experimental study indicates that the submerged hollow fiber ultrafiltration membrane can condense the concentration of sludge from 0.1%-0.3% to 2.5%. At 20°C, the system can operate continuously for 80 days with daily online backwashing with chemical additions only once, and the membrane flux can be recovered up to 97% by using NaClO and NaOH as chemical additions. The results show that the membrane flux is mainly affected by temperature, and has a positive linear relation to temperature with a slope of 0.368. After treated by submerged hollow fiber ultrafiltration membrane, the effluent can reach the National Standard for Drinking Water (GB5749-85), especially for the sludge water from sedimentation tanks and the backwashing water from filters in water supply plants.