Removal of malodorous gases from swine manure by a polyurethane biofilter inoculated with heterotrophic and autotrophic bacteria

Removal of malodorous gases from swine manure by a polyurethane biofilter inoculated with heterotrophic and autotrophic bacteria was investigated. Ammonia, hydrogen sulfide and other gases could be efficiently treated at 3-3.6 second of empty bed retention time by the polyurethane biofilter. In the range of SV 200-1,200h^-1 the average removal efficiency of odor was about 89% when the odor unit of inlet gas was below 4100. Odor elimination capacity of the polyurethane biofilter was 1.8 x 10⁵-5.0 x 10⁷ OU^-3.h-^-1 that were 84-90% of the inlet load. The critical loads of NH₃ and H₂S, which mean 97% removal with respect to the inlet loads, were 31 and 27 g.m^-3.h^-1 respectively. The maximum elimination capacities of NH₃ and H₂S were 56 and 157 g.m^-3.h^-1, respectively. Although the removability for NH₃ and H₂S was not influenced by H₂S/NH₃ ratio (ppmv/ppmv), the H₂S removability was inhibited by high H₂S concentration more than 80 ppmv.