Hongjie Wang

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, NH 3 -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 NH 3 -N by the IMBR was similar with that of the SMBR in that both the effluent COD were less than 30 mg/L and the NH 3 -N were less than 2 mg/L, while the removal efficiency of TN by IMBR was 75%, which was much better than that of SMBR. The MLSS and EPS concentration in SMBR were basically identical with that of IMBRs biotic zone. They were increased with the operation time, but they were significantly decreased in IMBRs 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.

Influencing Factors on Nitrogen Removal Performance of Combined Biological Aerated Filter for Secondary Effluent from Municipal WWTP

A pilot-scale study was conducted to investigate the principal influencing factors on nitrogen removal performance of combined biological aerated filter (CBAF), including external carbon source dosage, ratio of air to water and hydraulic loading rate, with inflow of secondary effluent form a municipal WWTP in Shenzhen city. Moreover, the optimal operation mode of CBAF was determined as follows: with 15~25 mg COD Cr /L of added carbon source, 2:1 of the ratio of air to water and 10 m 3 /m 2 -d of hydraulic loading rate, CBAF had an excellent and stable removal performance of nitrogen under this running mode. When the concentrations of NH 4 + -N and TN in the influent were 1.0~17.4 mg/L and 7~23 mg/L, the concentrations in the effluent were lower than 2 mg/L and 15 mg/L respectively. The water quality of the effluent was in accordance with the requirements of Water Quality Standard for Scenic of Environment Use (GB/T18921-2002).