Continuous deodorization and bacterial community analysis of a biofilter treating nitrogen-containing gases from swine waste storage pits

A biofilter inoculated with Arthrobacter sp. was applied to the simultaneous elimination of trimethylamine (TMA) and ammonia (NH₃) from the exhaust air of swine waste storage pits. The results showed that the biofilter achieved average removal efficiencies of 96.8 ± 2.5% and 97.2 ± 2.3% for TMA and NH₃, respectively. A near-neutral pH (7.3-7.4) was maintained due to the accumulation of acid metabolites and the adsorption of alkaline NH₃. Low moisture demand, low pressure drop and high biofilm stability in the system were other advantages. After long-term operation, the bacterial community structure showed that at least twenty-five bands were explicitly detected by a denaturing gradient gel electrophoresis (DGGE) method. However, the inoculated Arthrobacter sp. still maintained a dominant population (>50%). Paracoccus denitrificans' presence in the biofilter could play an important role in oxidizing NH₃ and reducing nitrite by heterotrophic nitrification and anaerobic denitrification.