title: Chemical Characterization of Low Molecular Weight Soluble Microbial Products in an Anaerobic Membrane Bioreactor.
abstract: Effluents from wastewater treatment systems contain a variety of organic compounds, including end products from the degradation of influent substrates, nonbiodegradable feed compounds, and soluble microbial products (SMPs) produced by microbial metabolism. It is important to identify the major components of these SMPs to understand what is in wastewater effluents. In this study, physical pretreatments to extract and concentrate low molecular weight SMPs (MW< 580 Da) from effluents were optimized. Liquid-liquid extraction (LLE) of a 200 mL effluent sample showed the best performance using a mixture of n-hexane, chloroform, and dichloromethane (70 mL) for extraction. For solid phase extraction (SPE), two OasisHLB cartridges were connected in-line to optimize recovery, and the eluted samples from each cartridge were analyzed separately to avoid overlapping peaks. Four solvents varying from polar to nonpolar (methanol, acetone, dichloromethane, and n-hexane) were selected to maximize the number of compound peaks eluted. A combination of SPE (OasisHLB) followed by LLE was shown to maximize compound identification and quantification. However, the compounds identified accounted for only 2.1 mg of chemical oxygen demand (COD)/L (16% of total SMP as COD) because many SMPs have considerably higher MWs. Finally, the method was validated by analyzing a variety of different reactor effluents and feeds.
authors.affiliation: Advanced Environmental Biotechnology Center, Nanyang Environment & Water Research Institute, Nanyang Technological University , 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore.
authors.forename: Chinagarn
authors.initials: C
authors.lastname: Kunacheva
authors.affiliation: Advanced Environmental Biotechnology Center, Nanyang Environment & Water Research Institute, Nanyang Technological University , 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore.|Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Chencheng
authors.initials: C
authors.lastname: Le
authors.affiliation: Advanced Environmental Biotechnology Center, Nanyang Environment & Water Research Institute, Nanyang Technological University , 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore.
authors.forename: Yan Ni Annie
authors.initials: YN
authors.lastname: Soh
authors.affiliation: Advanced Environmental Biotechnology Center, Nanyang Environment & Water Research Institute, Nanyang Technological University , 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore.|Department of Chemical Engineering, Imperial College London , London SW7 2AZ, U.K.
authors.forename: David C
authors.identifier: 0000-0002-6255-1153
authors.initials: DC
authors.lastname: Stuckey
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D059625:Liquid-Liquid Extraction; D008970:Molecular Weight; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D062065:Wastewater; D014874:Water Pollutants, Chemical