title: Improving the performance of membrane bioreactors by adding a metabolic uncoupler, 4-nitrophenol.
abstract: Effects of 4-nitrophenol (4NP) on the overall performance of membrane bioreactors (MBRs) were investigated in two bench-scale submerged MBRs. Positive impacts of 4NP on activated sludge production and membrane fouling were demonstrated over 45 days of stable operational period. After addition of 4-nitrophenol, the sludge production could be reduced effectively, but only a slight reduction in chemical oxygen demand removal was obtained. The effluent NH4(+)-N concentrations were almost the same in two MBRs. The transmembrane pressures (TMPs) and resistance R increased with increasing mixed liquor suspended solid concentration at each MBR. The average daily TMP increase rates in the control MBR reactor remained at about 0.23 kPa day(-1) and dropped to about 0.12 kPa day(-1) in the 4NP-MBR. Compared with the control MBR, a wider dispersion and lower peak of floc size, a lower zeta potential, and a lower extracellular polymeric substance concentration were observed in the 4NP-MBR.
authors: Department of Chemistry and Life Science, Leshan Normal University, Leshan 614004, People's Republic of China. qtang@ntu.edu.sg
authors: Tang
authors: T
authors: Qiong
authors: Lin
authors: L
authors: Song
authors: Ying
authors: Y
authors: Cheng
authors: Jun-Ru
authors: JR
authors: Xiong
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D008567:Membranes, Artificial; D009596:Nitrophenols / Q000494:pharmacology*; D012722:Sewage / Q000382:microbiology
chemical_list: D008567:Membranes, Artificial; D009596:Nitrophenols; D012722:Sewage; C024836:4-nitrophenol