title: Enrichment of denitrifying methanotrophic bacteria from municipal wastewater sludge in a membrane bioreactor at 20°C.
abstract: Simultaneous nitrogen and methane removal by the slow growing denitrifying methanotrophic bacterium 'Candidatus Methylomirabilis oxyfera' offers opportunities for a new approach to wastewater treatment. However, volumetric nitrite consumption rates should be increased by an order of magnitude before application in wastewater treatment becomes possible. A maximum volumetric nitrite consumption rate of 36 mg NO2(-)-N/L d was achieved in a membrane bioreactor inoculated with wastewater sludge and operated at 20°C. This rate is similar to maximum rates reported in literature, though it was thought that by strict biomass retention using membranes, higher rates would be achieved. In experiments lasting several years, growth was not stable: every experiment showed a decrease in activity after 1-2 years. The cause remains unknown. Rates increased after addition of copper and operating a membrane bioreactor at shorter hydraulic retention times. Further research should focus on long-term effects of copper addition and operation at hydraulic retention times in the order of hours using membrane bioreactors.
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands. Electronic address: christel.kampman@chalmers.se.
authors.forename: Christel
authors.initials: C
authors.lastname: Kampman
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands.
authors.forename: Hardy
authors.initials: H
authors.lastname: Temmink
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands.
authors.forename: Tim L G
authors.initials: TL
authors.lastname: Hendrickx
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands.
authors.forename: Grietje
authors.initials: G
authors.lastname: Zeeman
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands.
authors.forename: Cees J N
authors.initials: CJ
authors.lastname: Buisman
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors; D058440:Denitrification; D008567:Membranes, Artificial; D008697:Methane / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D008567:Membranes, Artificial; D008697:Methane; D009573:Nitrites; D012722:Sewage; D062065:Wastewater
keywords: Anaerobic methane oxidation; Denitrification; Low temperature; Membrane bioreactor; Methylomirabilis oxyfera