The Mechanism of Membrane Fouling on Submerged Flat Membrane MBR Treating of Domestic Wastewater

A test with submerged flat membrane bioreactor(MBR) to treat the mixed wastewater from dormitory and the dining room of university was carried out.The experiment system applied A/O process with nitrification tank and denitrification tank,with daily treatment of 4 m~3.The results showed that with BOD_5 concentration of 90～450(mg/L) and COD_(Cr) concentration of 120～900(mg/L) in the influent,the effluent BOD_5 concentration of 5～25(mg/L) and COD_(Cr) concentration of 8～45(mg/L) could be resulted,showing high removal efficiency.Meanwhile,the membrane fouling was studied,and the mechanism of membrane fouling affected by MLSS,size distribution of sludge and composition of raw water revealed.It is found that the diameter of sludge particles changes with the MLSS.When MLSS is higher than 20.000(g/L,) sludge particles diameter descends in evidence.Also,more small particles which can result in membrane fouling are resulted in.This phenomena was proved by experiment of membrane fouling when MLSS higher than 20.000(g/L.)