Influence of Ammonium Concentration on the Performance of an Inorganic Biofilter Treating Methane

Among the technologies available to reduce methane emitted from the pig industry, biofiltration seems to be an effective and inexpensive solution. In methane (CH4) biofiltration, nitrogen is an important macronutrient for the microorganisms growth. The objective of this research project was to study the effect of ammonium (NH4) on the performance, the biomass production and the nitrogen conversion of a biofilter treating methane. For NH4 concentrations ranging from 0.05 to 0.5 gN-NH4/L, the CH4 removal efficiency and the dioxide carbon production rate decreased linearly from 68 to 11.8 % and from 7.1 to 0.5 g/(m-h), respectively. The dry biomass content varied from 4.1 to 5.8 kg/(m filter bed). For the same range of concentrations, the ammonium conversion decreased while the specific nitrate production rate increased. The specific nitrate production rate presented negative values indicating denitrification in the biofilter. Keywords—Methane, biofiltration, pig, ammonium, nitrification, denitrification.