title: Effect of Low-Density Static Magnetic Field on the Oxidation of Ammonium byNitrosomonas europaeaand by Activated Sludge in Municipal Wastewater.
abstract: Ammonium removal is a key step in biological wastewater treatment and novel approaches that improve this process are in great demand. The aim of this study is to test the hypothesis that ammonium removal from wastewater can be stimulated by static magnetic fields. This was achieved by analysis of the effects of static magnetic field (SMF) on the growth and activity ofNitrosomonas europaea, a key ammonia-oxidising bacterium, where increased growth and increased ammonia oxidation rate were detected when bacteria were exposed to SMF at 17 mT. Additionally, the effect of SMF on mixed cultures of ammonia oxidisers in activated sludge, incubated in sequencing batch bioreactors simulating wastewater treatment process, was assessed. SMFs of 30 and 50 mT, but not of 10 mT, increased ammonium oxidation rate in municipal wastewater by up to 77% and stimulated ammonia oxidiser growth. The results demonstrate the potential for use of static magnetic fields in increasing ammonium removal rates in biological wastewater treatment plants.
authors.affiliation: Ptuj Municipal Service Corporation, Puhova ulica 10, SI-2250 Ptuj, Slovenia; University of Ljubljana, Biotechnical Faculty, Department of Food Science and Technology, Večna pot 111, SI-1000 Ljubljana, Slovenia.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Filipič
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Department of Food Science and Technology, Večna pot 111, SI-1000 Ljubljana, Slovenia.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kraigher
authors.affiliation: Ptuj Municipal Service Corporation, Puhova ulica 10, SI-2250 Ptuj, Slovenia.
authors.forename: Brigita
authors.initials: B
authors.lastname: Tepuš
authors.affiliation: University of Maribor, Faculty of Mechanical Engineering, Institute for Engineering Materials and Design, Smetanova ulica 17, SI-2000 Maribor, Slovenia.
authors.forename: Vanja
authors.initials: V
authors.lastname: Kokol
authors.affiliation: Ptuj Municipal Service Corporation, Puhova ulica 10, SI-2250 Ptuj, Slovenia.
authors.forename: Ines
authors.initials: I
authors.lastname: Mandić-Mulec
keywords: ammonia-oxidising bacteria; biological wastewater treatment; nitrification; sequencing batch reactors; static magnetic field