Pollutants removal effect and membrane fouling alleviating by an improved submerged membrane bioreactor for domestic wastewater treatment

The effect of an improved membrane bioreactor (IMBR) on COD, NH3-N and TN removal and membrane fouling alleviating was investigated through a comparative study with a traditional submerged membrane bioreactor (SMBR). The variations of trans-membrane pressure (TMP), concentration of mixed liquid suspend sludge (MLSS) and extracellular polymeric substance (EPS) was also conducted through the long-term operation. The results showed that the removal efficiency of COD and NH3-N by the IMBR was similar with that of the SMBR in that both the effluent COD were less than 30mg/L and the NH3-N were less than 2mg/L, while the removal efficiency of TN by IMBR was 75%, which was much better than that of SMBR. The MESS and EPS concentration in SMBR were basically identical with that of IMBR's biotic zone. They were increased with the operation time, but they were significantly decreased in IMBR's membrane zone than that of SMBRs'. The IMBR was more capable of alleviating membrane fouling, and it had been cleaned only twice while the SMBR who had been cleaned 5 times during the period of about 90 days laboratory performance.