title: Effect of process design and operating parameters on aerobic methane oxidation in municipal WWTPs.
abstract: Methane is a potent greenhouse gas and its emission from municipal wastewater treatment plants (WWTPs) should be prevented. One way to do this is to promote the biological conversion of dissolved methane over stripping in aeration tanks. In this study, the well-established Activated Sludge Model n°1 (ASM1) and Benchmark Simulation Model n°1 (BSM1) were extended to study the influence of process design and operating parameters on biological methane oxidation. The aeration function used in BSM 1 was upgraded to more accurately describe gas-liquid transfer of oxygen and methane in aeration tanks equipped with subsurface aeration. Dissolved methane could be effectively removed in an aeration tank at an aeration rate that is in agreement with optimal effluent quality. Subsurface bubble aeration proved to be better than surface aeration, while a CSTR configuration was superior to plug flow conditions in avoiding methane emissions. The conversion of methane in the activated sludge tank benefits from higher methane concentrations in the WWTP's influent. Finally, if an activated sludge tank is aerated with methane containing off-gas, a limited amount of methane is absorbed and converted in the mixed liquor. This knowledge helps to stimulate the methane oxidizing capacity of activated sludge in order to abate methane emissions from wastewater treatment to the atmosphere.
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, Netherlands; Department of Biosystems Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium. Electronic address: m.r.j.daelman@tudelft.nl.
authors.forename: Matthijs R J
authors.initials: MRJ
authors.lastname: Daelman
authors.affiliation: Department of Biosystems Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
authors.forename: Tamara
authors.initials: T
authors.lastname: Van Eynde
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, Netherlands.
authors.forename: Mark C M
authors.initials: MCM
authors.lastname: van Loosdrecht
authors.affiliation: Department of Biosystems Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
authors.forename: Eveline I P
authors.initials: EIP
authors.lastname: Volcke
mesh_terms: D000388:Air; D018533:Biomass; D019149:Bioreactors; D002138:Calibration; D002947:Cities; D003198:Computer Simulation; D005160:Facility Design and Construction; D057232:Global Warming; D008697:Methane / Q000737:chemistry*; D009609:Nitrous Oxide / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D011312:Pressure; D012722:Sewage; D014865:Waste Disposal, Fluid; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D008697:Methane; D009609:Nitrous Oxide; D010100:Oxygen; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: ASM1; Activated sludge; Climate footprint; Greenhouse gasses; Methanotrophic bacteria; Wastewater treatment