Membrane fouling is a common problem in membrane bioreactor(MBR).Regular cleaning of membrane cassettes is an effective method to alleviate membrane fouling in engineering applications.The arrayed flat sheet membrane,as a kind of membrane with corrugation,has the advantages of high density,high flux and being free of off-line cleaning.This article introduces the application case of arrayed flat sheet membrane in integrated MBR-based sewage purification equipment and its chemical cleaning scheme.In this case,the membrane fouling was serious,resulting in a pure water flux of only 7％of the new membrane.The amounts of Fe and Ca in the inorganic-organic composite layer on the membrane surface reached 5 384 mg/m2 and 1 400 mg/m2,respectively,and the total organic carbon content reached 548 mg/m2(with an polysaccharide concentration of 400 mg/m2).After a restorative online cleaning using oxalic acid and sodium hypochlorite,the transmembrane pressure of the arrayed flat sheet membrane recovered from 29 kPa to 11 kPa.The equipment was then operated continuously at a flux of 25 L/(m2·h),with a monthly maintenance cleaning using 500 mg/L sodium hypochlorite solution.During the five-month monitoring period,the transmembrane pressure did not fluctuate significantly,showing good operation stability.The result indicated that organic matter played a key role in the inorganic-organic combined fouling,and the maintenance cleaning using sodium hypochlorite could effectively remove organic foulants from the arrayed flat sheet membrane,thus curbing the formation of subsequent combined fouling.
维普
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