title: Balancing of nitrogen conversion in deammonifying biofilms through batch tests and GC/MS.
abstract: Growth carriers from a technical deammonifying moving-bed WWTP were used in batch tests to determine possible N-conversion reactions under varying oxygen and substrate conditions. Deammonification, denitrification, and nitrification reactions could be proved using conventional analysis, combined with gas chromatography/mass spectrometry analysis to get additional information about 15N-isotope labelled gaseous end products of the different reactions. In this orientating study N2O could be observed in some cases up to 12% of the total gas production. N2O production came from incomplete denitrification processes under anoxic or oxygen-limiting conditions and in the absence of organic substrate, as if structural components of deammonifying biofilms play a crucial role for the portion of side-reactions, leading to undesirable gaseous end products.
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D018441:Biofilms; D019149:Bioreactors; D008401:Gas Chromatography-Mass Spectrometry; D009584:Nitrogen / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000641:Ammonia; D009584:Nitrogen