Fouling Suppression And Operation Effect In Non-Woven MBR By Using Electric Field

MBR is a kind of efficient technology for water treatment,because it has good and stable effluent water quality,compact structure,small space,high concentration of mixed liquid suspended solids is widely used in the field of sewage treatment,more and more attention by people.However,the existence of membrane fouling and the high cost of membrane components hinder the further development and application of MBR.At present,there are some problems such as high cost of membrane module and simple electric field function and insufficient research on reducing membrane pollution in the research of additional electric field MBR.Therefore,low cost and new membrane material development and research as well as the control of electric field on membrane pollution become the key points to solve the above problems.This test to select cheap non-woven fabric as membrane materials to build membrane module,and an electric field non-woven MBR with electric flocculation and electric field force was designed and built,and from the optimal process parameters,removing pollutants,membrane fouling control,sludge characteristics,mixed liquid characteristic,electrode materials,non-woven fabric membrane material,filter cake layer structure and other aspects were studied.By measuring the water quality and microbial activity of the applied electric field non-woven membrane bioreactor（EMBR）under different operating parameters,the optimal operating conditions of the reactor were obtained:intermittent operation and applying an electric field for 2 minutes,plate spacing of 3.0cm,voltage of 2.5V,hydraulic retention time of 8.5h.Under the optimal process parameters,the MBR and EMBR are compared under the same operating conditions.The results show that the average effluent COD concentration of MBR and EMBR are 23.01mg·L^-1 and 13.20mg·L^-1 respectively.The average effluent COD removal rate of EMBR is 95.15%,which is higher than that of the control system（91.77%）.The average removal rate of effluent ammonia nitrogen in MBR was 90.03%,while that in EMBR was 92.09%.The removal rate of TP from MBR effluent reached 22.87%,while the removal rate of EMBR was higher,reaching 43.59%.The average effluent turbidity and turbidity removal rate of MBR and EMBR were 3.72NTU,3.31NTU,and 92.98%,93.13%.The average sludge concentration of MBR was 5034mg·L^-1,while that of EMBR was 7957mg·L^-1.Compared with MBR,the average sludge concentration increased by2923mg·L^-1.Overall,the SVI value of EMBR sludge is lower than that of MBR sludge.The sludge particle size of EMBR is larger,EMBR has a lower membrane fouling growth rate,and EMBR also reduces R _t,R _c and R _p to a certain extent.Compared with MBR sludge specific resistance,EMBR sludge specific resistance is smaller,indicating that sludge filtration and dehydration performance in EMBR unit is better.Most of the iron ions dissolved from the plate enter the sludge and are used by microorganisms.The filtration resistance of supernatant and mixture of EMBR decreased compared with MBR.Under the action of electric field,the rapid filtration of sludge mixture of the two units is different,and the Zeta potential of the mixture in EMBR was higher than that in MBR.The content of pollutants in cake layer of non-woven membrane surface of EMBR is lower.The characterization of non-woven film shows that the presence of electric field can alleviate the membrane pollution on the surface of non-woven film.