Abstract
Hydrogen sulfide (H2S) is one of the main contaminants found in biogas which is one of the end products of the anaerobic biodegradation of proteins and other sulfur-containing compounds in solid waste. The presence of H2S is one of the factors limiting the valorization of biogas. To valorize biogas, H2S and other contaminants must be removed. This study evaluated the performance of a pilot-scale biotrickling filter system on H2S removal from landfill biogas. The biotrickling filter system, which was packed with stainless-steel pall rings and inoculated with an H2S-oxidizing consortium, was designed to process 1 to 10 SCFM of biogas and used to determine the removal efficiency of a high concentration of hydrogen sulfide from landfill biogas. The biofiltration system consisted of two biotrickling filters connected in series. Results indicate that the biofiltration system reduced H2S concentration by 94–97% without reduction of the methane concentration in the outlet biogas. The inlet concentration of hydrogen sulfide, supplied to the two-phase bioreactor, was in the range of 900 to 1500 ppmv. The hydraulic retention times (HRT) of the two biotrickling filters were 3.9 and 0.9 min, respectively. Approximately 50 ppmv of H2S gas was detected in the outlet gas. The maximum elimination capacity of the biotrickling filter system was found to be 272 g H2S.m− 3.h− 1. During the biological process, the performance of biotrickling filter was not affected when the pH of the recirculated liquid decreased to 2–3. The overall performance of the biotrickling filter system was described using a modified Michaelis–Menten equation, and the Ks and Vm values for the biosystem were 34.7 ppmv and 200 mg H2S/L.h− 1, respectively.
Oxidation of volatile reduced sulphur compounds in biotrickling filter inoculated with Thiobacillus thioparus