Research On Cogulation Enhancing Removal Of Phosphors And Mitigating Membrane Fouling In Membrane Bioreactor

In order to protect the marine environment,IMO(International Maritime Organization)formulated the MARPOL73/78 Convention,which made strict regulation of emission standards of ship domestic sewage.In the 64th MEPC(Mariteme Environment Protection Committee)meeting,the clear emission standards of total nitrogen(TN)and total phosphorus(TP)of ship domestic sewage were made first time.Because of its small space on board and excellent ability of decontamination,MBR(Membrane Bioreactor)has a significant advantage in the field of ship domestic sewage treatment.However,its poor effect of denitrification and phosphorus removal,membrane fouling and other technical problems are solved urgently.Therefore,to optimize treatment processing by adding coagulant to MBR is of great significance for enhancing its effect of phosphorus removal and mitigating membrane fouling.In this paper,MBR and MCBR(Membrane Coagulaiton Bioreactor)were used to treat ship domestic sewage,respectively,and their effects of decontamination and mechanisms of membrane fouling were investigated.In order to study the efficiency of decontamination of MBR treating ship domestic sewage in the long run,and its removal effects of CODc,,NH3-N,TN,TP and turbidity were investigated,respectively.In order to determine the optimum dose of the coagulant added to MCBR,phosphorus removal coagulation tests were conducted.In order to study the efficiency of decontamination of MCBR treating ship domestic sewage in the long run,its removal effects of CODCr,NH3-N,TN,TP and turbidity were investigated and compared with MBR,respectively.The experimental results showed that the addition of PAC(Aluminium Polychlorid)made few influence to the removal effect of TN but dramaticlly improved the removal effect of TP,and the average removal rate of TP was increased from 15.6%to 89.1%.Moreover,the membrane fouling of MBR and MCBR were investigated,and the results showed that the addition of PAC could effectively mitigate membrane fouling.The time TMP reached 50kPa was approximately prolonged to 1.5 times the original.By investigating the change of TMP(Transmembrane pressure),resistance distribution of foulant layers,elemental composition of foulants,MLSS,pH,EPS,SMP and other factors,in combination with sludge flocs size analysis and Zeta potential analysis,the mechanism of addition of PAC mitigating membrane fouling was analyzed.