The Study On Membrane Cleaning Method And Operation Commissioning Test As The PVDF/PVP Improved Ultrafiltration Membrane Used In Urban Sewage Recycling

Ultrafiltration technology used in urban sewage depth processing, can reduce theemissions of pollutants, and get multi-objective use excellent water, therefore, muchattention has been paid. however, in view of the complicated composition of the urbansewage, the membrane flux decline caused by membrane fouling has become a majorobstacle of the promotion of membrane technology. This paper presents a pilot studywhich uses coagulation, sedimentation and sand filtration as pretreatment for theautomatic membrane separation device to treat secondary effluent. The aim of thisstudy is to investigate the effect of different operational conditions and chemicalenhanced backwash（CEB） on the inhibition of membrane fouling, provide certainreference for practical engineering application.The results show that:（1）Using the ultrafiltration method for the determination dissolved organic mattermolecular weight distribution of Secondary Effluent of urban wastewater. It shows thatorganic matter molecular weight distribution of urban wastewater is stable, the organicmatter of <3k occupied50-63%, the organic matter of>60k occupied5-10%in TOC;And the organic matter of <3k occupied53-61%, the organic matter of>60k occupied2-12%in UV254. Urban secondary water soluble organic matter is given priority to thesmall molecules.（2） As the coagulation, sedimentation and sand filtration as pretreatment to treaturban wastewater can remove organic matter effectively, especially for removing ofturbidity. Average removal rates of UV254、COD、phosphate、ammonia is reduced to 69.8%、64.2%、65.4%、67.45%compared with raw water，ultrafiltration technologyas the core test shows that the regeneration system can realize the depth of thesecondary effluent.（3）The experiment researches and determines the ultrafiltration membraneconstant filtration flux the membrane fouling rate and the best operation control mode，the test shows that the backwash flow changes can substantially reduce membranefouling, the CEB can inhibit the membrane fouling, hydraulic cleaning and CEB canguarantee long-time stable operation.（4） The test analysis and sums up the proper operation control parameter forimproved ultrafiltration membrane, and determines the CEB frequency、backwashingwater consumption、 backwashing pressure and water production rate, the waterconsumption of50-120L·m^-2·h^-1is1.38-5.97L·m^-2、backwashing pressure is0.04-0.08MPa, the CEBfrequency is40^-120cycles, water production rate is82.56%-88.31%,provide areference for engineering practice.