title: Quantification and kinetic characterization of soluble microbial products from municipal wastewater treatment plants.
abstract: Soluble microbial products (SMP) formed by microorganisms in wastewater treatment plants (WWTPs) adversely affect final effluent quality and treatment efficiency. It is difficult to distinguish SMP from residual proteins, lipids and carbohydrates present in the influent that may persist during treatment. No method is currently available to determine quantitatively the extent to which SMP contribute to organic discharges from municipal WWTPs. In this work a modeling approach is presented which allows the SMP fraction of the effluent of a municipal WWTP to be quantified and described. The model is validated, in terms of utilization-associated products, biomass-associated products and extracellular polymeric substances, using influent from a municipal WWTP. SMP was found to account for, on average, 27 mg/L of chemical oxygen demand (COD), or 61% of the total COD in the WWTP effluent. Over 90% of the SMP was comprised of biomass-associated products. Five main factors influencing SMP formation in WWTP were evaluated. Neither wastewater composition nor mixed liquor suspended solids concentration was found to affect SMP production. On the other hand, a positive correlation was observed for SMP formation with both solids retention time and influent COD concentration, and a negative correlation with hydraulic retention time. Thus, operating or designing WWTPs with short solids retention and long hydraulic retention times could be considered as solutions for minimizing SMP production.
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China.
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Xie
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China.
authors.forename: Bing-Jie
authors.initials: BJ
authors.lastname: Ni
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China.
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Sheng
authors.affiliation: Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, School of Biological Sciences, 637551 Singapore. Electronic address: twseviour@ntu.edu.sg.
authors.forename: Thomas
authors.initials: T
authors.lastname: Seviour
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China. Electronic address: hqyu@ustc.edu.cn.
authors.forename: Han-Qing
authors.initials: HQ
authors.lastname: Yu
mesh_terms: D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D002681:China; D002947:Cities; D007700:Kinetics; D008962:Models, Theoretical; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000032:analysis*
chemical_list: D062065:Wastewater
keywords: Activated sludge; Chemical oxygen demand (COD); Effluent; Microorganisms; Soluble microbial products (SMP); Wastewater treatment plant (WWTP)