Study On The Performance Of Folded Membrane-Dynamic Membrane Bioreactor For Domestic Sewage Treatment

Dynamic Membrane Bioreactor(DMBR)not only retains the advantages of traditional MBR process,but also has the advantages of low cost of membrane substrate,large membrane flux,easy control of membrane fouling,small footprint and good effluent quality.The field of sewage treatment has great application prospects.The paper uses a non-woven folded film as a membrane module to construct a dynamic membrane bioreactor to treat domestic sewage.The sequential batch operation mode is adopted,the treatment effect of the reactor,suitable process conditions,the influence of iron salt addition on the system and Experimental research has been carried out on membrane fouling control.The effect of the folded membrane-dynamic membrane bioreactor on domestic sewage treatment is affected by cycle time,aerobic anaerobic time ratio,and effluent volume exchange ratio.The experimental results show that the suitable operating conditions for the folded membrane-dynamic membrane bioreactor are: cycle time is 8h,aerobic anaerobic time ratio is 2:1,and effluent volume exchange ratio is 0.3,at this time COD,TN,TP and ammonia nitrogen The average effluent concentrations were 20.99mg/L,16.67mg/L,1.05mg/L and 6.80mg/L,respectively;the effluent quality accorded with the first-class B standard of Pollutant Discharge Standard for Urban Sewage Treatment Plants(GB18918-2002).When the iron salt dosage reached 5% of the sludge iron content,the reactor treated the sewage best.At this time,the average removal rate of COD,TN,TP and ammonia nitrogen in the effluent was compared with that before the iron salt was added.The increase of 4.1%,9.0%,9.3%,5.9%,TP removal rate was the largest;and the sedimentation performance of activated sludge after the addition of iron salt is improved,and the floc structure of sludge is more compact,indicating that iron salt has been strengthened.Reactor operating performance.When the gravity time of the reactor exceeds 30 min,the dynamic membrane is washed by reverse aeration backwashing.The test results show that the backwashing aeration intensity and backwashing time have certain influence on the recovery time of the biodynamic membrane.When the aeration intensity is 4m3/(m2.h)and the backwashing time is 5min,the recovery of the biodynamic membrane takes 24 min.After the biodynamic membrane is recovered,the effluent turbidity remains below 2NTU,which can effectively clean the contaminated dynamic membrane.