ABSTRACT
Membrane bioreactor (MBR) technology has been used in industrial wastewater treatment plants. Membrane fouling still is one of the key problems limiting the stable operation of MBR, the kinds of cleaning reagents on the membrane surface and the cleaning strategies are researched extensively. Focused on the fouled membrane from a liquor-making treatment plant, the influence of chemical cleaning strategies on cleaning efficiency is investigated. Sodium hypochlorite and oxalic acid are two representative cleaning reagents widely used in MBR membrane cleaning. The effect of acid washing followed by alkaline washing is better than that of alkaline washing followed by acid washing, chemical cleaning routine can effectively extend the life of the membrane. The results show that the membrane organic pollutants can be cleaned with the effective chlorine concentration of 2000 ~ 5000mg/L for 2 ~ 3 hours and with the dosage of 2L/each membrane element for 2 hours, the membrane inorganic pollutants can be cleaned with the oxalic acid concentration of 1000mg/L for 1 ~ 2 hours and with the dosage of 2L/each membrane element for 2 hours. Chemical cleaning under 0.8M3/ (M2•h) aeration condition has a better cleaning effect.
