title: Sulfur toxicity and media capacity for H2S removal in biofilters packed with a natural or a commercial granular medium.
abstract: Two types of media, a natural medium (wood chips) and a commercially engineered medium, were evaluated for sulfur inhibition and capacity for removal of hydrogen sulfide (H2S). Sulfate was added artificially (40, 65, and 100 mg of S/g of medium) to test its effect on removal efficiency and the media. A humidified gas stream of 50 ppm by volume H2S was passed through the media-packed columns, and effluent readings for H2S at the outlet were measured continuously. The overall H2S baseline removal efficiencies of the column packed with natural medium remained >95% over a 2-day period even with the accumulated sulfur species. Added sulfate at a concentration high enough to saturate the biofilter moisture phase did not appear to affect the H2S removal process efficiency. The results of additional experiments with a commercial granular medium also demonstrated that the accumulation of amounts of sulfate sufficient enough to saturate the moisture phase of the medium did not have a significant effect on H2S removal. When the pH of the biofilter medium was lowered to 4, H2S removal efficiency did drop to 36%. This work suggests that sulfate mass transfer through the moisture phase to the biofilm phase does not appear to inhibit H2S removal rates in biofilters. Thus, performance degradation for odor-removing biofilters or H2S breakthrough in field applications is probably caused by other consequences of high H2S loading, such as sulfur precipitation.
authors.affiliation: Department of Environmental Engineering, Texas A&M University-Kingsville, Kingsville, TX 78363, USA. kjones@tamuk.edu
authors.forename: Kim
authors.initials: K
authors.lastname: Jones
authors.forename: Alvaro
authors.initials: A
authors.lastname: Martinez
authors.forename: Mohammad
authors.initials: M
authors.lastname: Rizwan
authors.forename: Jim
authors.initials: J
authors.lastname: Boswell
mesh_terms: D000393:Air Pollutants / Q000302:isolation & purification*; D000397:Air Pollution / Q000517:prevention & control*; D001673:Biodegradation, Environmental; D001681:Biological Assay; D005374:Filtration; D009812:Odorants / Q000517:prevention & control; D010316:Particle Size; D013455:Sulfur / Q000633:toxicity; D013458:Sulfur Dioxide / Q000302:isolation & purification*
chemical_list: D000393:Air Pollutants; D013458:Sulfur Dioxide; D013455:Sulfur