title: Characterization of soluble microbial products (SMPs) in a membrane bioreactor (MBR) treating synthetic wastewater containing pharmaceutical compounds.
abstract: This study investigated the behaviour and characteristics of soluble microbial products (SMP) in two anoxic-aerobic membrane bioreactors (MBRs): MBRcontrol and MBRpharma, for treating municipal wastewater. Both protein and polysaccharides measured exhibited higher concentrations in the MBRpharma than the MBRcontrol. Molecular weight (MW) distribution analysis revealed that the presence of pharmaceuticals enhanced the accumulation of SMPs with macro- (13,091 kDa and 1587 kDa) and intermediate-MW (189 kDa) compounds in the anoxic MBRpharma, while a substantial decrease was observed in both MBR effluents. Excitation emission matrix (EEM) fluorescence contours indicated that the exposure to pharmaceuticals seemed to stimulate the production of aromatic proteins containing tyrosine (10.1-32.6%) and tryptophan (14.7-43.1%), compared to MBRcontrol (9.9-29.1% for tyrosine; 11.8-42.5% for tryptophan). Gas chromatography-mass spectrometry (GC-MS) analysis revealed aromatics, long-chain alkanes and esters were the predominant SMPs in the MBRs. More peaks were present in the aerobic MBRpharma (196) than anoxic MBRpharma (133). The SMPs identified exhibited both biodegradability and recalcitrance in the MBR treatment processes. Only 8 compounds in the MBRpharma were the same as in the MBRcontrol. Alkanes were the most dominant SMPs (51%) in the MBRcontrol, while aromatics were dominant (40%) in the MBRpharma. A significant decrease in aromatics (from 16 to 7) in the MBRpharma permeate was observed, compared to the aerobic MBRpharma. Approximately 21% of compounds in the aerobic MBRcontrol were rejected by membrane filtration, while this increased to 28% in the MBRpharma.
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, #06-10, Singapore, 637141, Singapore. Electronic address: dqzhang@ntu.edu.sg.
authors.forename: Dongqing
authors.initials: D
authors.lastname: Zhang
authors.affiliation: School of Civil Engineering & Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, 4350 Australia.
authors.forename: Antoine Prandota
authors.initials: AP
authors.lastname: Trzcinski
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, #06-10, Singapore, 637141, Singapore.
authors.forename: Chinagarn
authors.initials: C
authors.lastname: Kunacheva
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Avenue, Singapore, 639798, Singapore; Department of Chemical Engineering, Imperial College London, SW7 2AZ, UK.
authors.forename: David C
authors.initials: DC
authors.lastname: Stuckey
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, #06-10, Singapore, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Avenue, Singapore, 639798, Singapore.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, #06-10, Singapore, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Avenue, Singapore, 639798, Singapore.
authors.forename: Soon Keat
authors.initials: SK
authors.lastname: Tan
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, #06-10, Singapore, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Avenue, Singapore, 639798, Singapore. Electronic address: WJNg@ntu.edu.sg.
authors.forename: Wun Jern
authors.initials: WJ
authors.lastname: Ng
mesh_terms: D019149:Bioreactors; D008401:Gas Chromatography-Mass Spectrometry; D008567:Membranes, Artificial; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D008567:Membranes, Artificial; D062065:Wastewater
keywords: Anoxic-aerobic; Membrane bioreactor (MBR); Pharmaceutical compounds; Soluble microbial products (SMP); Wastewater treatment