| Petroleum-contaminated vapor streams are commonly encountered during field remediation projects associated with off-gases produced from soil vapor extraction (SVE) operations. The first study of this dissertation investigated the applicability of biofiltration for treatment of SVE emissions. Experiments were performed using bench-scale biofilters for removal of JP-4 jet fuel vapors from contaminated air streams. Three different packing materials, granular activated carbon, yard waste compost, and bark compost, were chosen as biofilter media to evaluate their effectiveness and compare their overall performance.; The results indicated that the effectiveness of a biofilter was largely governed by the properties and characteristics of the support medium. In general, selection of the proper biofilter medium is a significant step toward developing successful biofilter operation. Additionally, care must be taken to optimize the operating parameters such as moisture content, pH, and nutrient availability in order to maintain effective treatment of pollutants.; Biofiltration for treatment of waste air streams containing hydrogen sulfide and volatile organic compounds (VOCs) poses particular difficulties because microbial oxidation of the sulfide generates acid, which accumulates in the biofilter medium, reducing pH. The second study of this dissertation assessed the feasibility of co-treatment of H2S and VOCs in low-pH biofilters. Bench-scale biofilters were operated for removal of benzene, toluene, or xylene and with a mix of all three in the presence of hydrogen sulfide. Inorganic media including a commercially available material called isolite, lava rock, and gravel were used as packing materials.; The low-pH biofiltration system demonstrated effective performance for simultaneous removal of H2S and VOCs. Hydrogen sulfide was readily removed with efficiencies typically near 99% throughout the operation period. BTX compounds were treated differently depending on pollutant type and concentration, acclimation history and characteristics, and substrate interactions. The results suggested that low-pH biofilters may be indeed practical for removing VOCs in application where sulfide oxidation or other transformation generate acid. Most probably, the microbial community in biofilters will adapt to the environmental conditions present in the reactors. Once an adequate microbial population has been established, the efficient contaminant treatment can be obtained. |
