Ultrafiltration Combination Process On Raw Water Quality Adaptability Research

Coagulation, potassium permanganate preoxidation, activated carbon adsorption, and ultrafiltration(UF) combination process were used in dealing with sudden pollution of turbidity, heavy metals and organics with reservoir water derived from the Yellow River and the simulated water. In order to supply the basis for the establishment of emergency response plan and technical assistance for a long-term stable operation of the membrane system, the suitability of UF combination process had been studied to cope with sudden pollution and two groups of UF combination process operation features were compared.The coagulation,activated carbon adsorption, ferrous sulfate reduction had been used in emergency treatment of sudden hexavalent chromium pollution.The results show that the polyaluminium chloride as a coagulant in addition to the chrome effect is better than polymeric ferric sulfate, aluminium chloride and ferric chloride. Increasing coagulant dosage cannot effectively remove hexavalent chromium. When we used activated carbon adsorption to remove hexavalent chromium, the optimum pH value is 3~4, and the optimal adsorption time is 30 min.then increasing coagulant dosage can effectively remove hexavalent chromium.Ferrous sulfate reduction can remove hexavalent chromium quickly and effectively; The addition of coagulant can increase total chromium removal efficiency significantly. The optimal dosing interval of ferrous sulfate and ferric chloride in the neutral condition is 10 min,and the optimum pH value is between7 and 8.Ferrous sulfate reduction/short-range precipitation/UF and ferrous sulfate reduction/ coagulation/short-range precipitation/UF composite process can deal with sudden hexavalent chromium pollution effectively, which make total chromium concentration of ultrafiltration effluent is lower than 0.05mg/L, and the Standards for Drinking Water Quality(GB 5749 — 2006) is met. Both the ultrafiltration combined processes can control membrane fouling effectively, which play a very important role in water quality.In order to cope with sudden pollution of turbidity, humus and polysaccharide, activated carbon adsorption, coagulation and sedimentation, potassium permanganate preoxidation and UF combination process were studied.The results show that compared with the potassium permanganate preoxidation and activated carbon adsorption, coagulation have a good effect on humic acid removal. Compared with potassium permanganate preoxidation, coagulation and adsorption on polysaccharide removal effect is better. And activated carbon adsorption-ultrafiltration, potassium permanganate peroxidation-ultrafiltration, coagulation-ultrafiltration of humus, polysaccharide pollution showed better adaptability.Conventional technique-ultrafiltration and short flow-ultrafiltration were compared, and studied the effect of return sludge for UF combination process. The results show that the conventional process of turbidity and organic matter removal effect were better than short process, and the conventional process- ultrafiltration combined technology of membrane pollution control effect is good, but short process technology of membrane fouling control remains to be further optimized. Return sludge would improve short process technology on the treatment effect of water quality, help to improve the water quality, and slow the membrane fouling. Coagulation- ultrafiltration adapt to different water quality studies have shown that the Yangtze river water quality is better than the local water supply, help to improve the local water quality after mixing, slow the membrane fouling, ultrafiltration process showed better adaptability.