Simultaneous nitrogen and phosphor removal in an aerobic submerged membrane bioreactor

Article type: Research Article

Authors: WANG, Zhi-wei | WU, Zhi-chao | GU, Guo-wei | YU, Guo-ping | MA, Lu-ming

Affiliations: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China

Note: [] Corresponding author. E-mail: [email protected]

Abstract: Simultaneous nitrification and denitrification (SND) effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids (MLSS) 19–20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor (MBR) and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2–0.3 mg/L. The main mechanisms governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate (PFS) addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances (EPS) of mixed liquor.

Keywords: membrane bioreactor (MBR), flat-sheet membrane, simultaneous nitrification and denitrifiction (SND), phosphor removal, wastewater treatment, oxygen transfer rate

Journal: Journal of Environmental Sciences, vol. 18, no. 3, pp. 439-445, 2006