Field Measurements and Modeling of Two-Stage Biofilter that Treats Odorous Sulfur Air Emissions

Because the presence of hydrogen sulfide (H2S) and methyl mercaptan (MeSH) inhibits the removal of some organic reduced sulfur compounds (e.g., dimethyl sulfide, Me2S) in biofilters, a two-stage biofilter may be an appropriate method to treat a mixture of reduced sulfur compounds. This work studied the treatment of odorous air emissions [a mixture of H2S, MeSH, Me2S, and dimethyl disulfide (Me2S2)] using a two-stage biofilter. H2S had the highest overall removal efficiency (96%) followed by MeSH and Me2S (90 and 91% removal, respectively) and Me2S2 (81%). Most of the removal of H2S, MeSH, and Me2S2 occurred in the primary biofilter (72% H2S, 66% MeSH, and 52% Me2S2), while most of the Me2S removal occurred in the secondary biofilter (64% Me2S). A dynamic model that describes biofiltration was calibrated and validated to H2S and MeSH field data. This is the first time a model was evaluated with organic odor-causing sulfur compound data obtained from a biofilter packed with compost and wood chips. Model simulations showed that H2S removal in a lava rock packed biofilter would be better than in a similar biofilter packed with compost and wood chips.