Livestock Air Treatment Using Pva‐coated Powdered Activated Carbon Biofilter

This study evaluated the efficacy of polyvinyl alcohol (PVA)‐coated powdered activated carbon particles as a biofiltration medium. This material exhibited excellent properties as a biofiltration medium with a water holding capacity of 1.39 g H2O/g‐dry PVA; wet porosity of 0.53; and significantly lower pressure drop than that of commonly reported biofilter media such as compost. Bench‐scale biofilters treating off‐gas by aerating flushed swine manure samples were used to evaluate ammonia and hydrogen sulfide removal capacities along with greenhouse gas production potentials. Although ammonia adsorption capacity was much lower than granular activated carbon, the PVA biofilter medium retained its ammonia removal capacity because of suspected biological nitrification. The PVA biofilters continued to remove 80% of ammonia in the air for the entire 37 days of operation. While the biofilters produced 0.14 g N2O‐N/L‐wet PVA, another greenhouse gas methane production was negligible. Hydrogen sulfide was effectively removed (97%) by the PVA biofilters.