Treatment of odor gas containing hydrogen sulfide by multilayer biofilter

In order to solve the problems of high pressure drop and low purifying efficiency existing in the single layer biofilter, using corncob as filler, in contrast to the single layer biofilter, multilayer biofilter used in treating H2S-contaminated gas streams was investigated. The suitable technological conditions and removal kinetics have been studied in this paper. The results showed that the multilayer biofilter had a higher removal rate of H2S than that of the single layer biofilter. The removal efficiency of H2S was more than 90% when the inlet hydrogen sulfide was lower than 140 mg/m3. When the inlet volumetric loading rate of H2S below 42.2 g/(m3·d), the bottom layer which was 200 mm thick removed more than 95% of the total removal rate. The biofilter worked well as the moisture content ranged from 55% to 70%. The removal kinetics were researched based on the Michaelis - Menten model, two kinetic parameters were Ksp with a value of 12.4 mg/m3 and Vm with a value of 909 g/(m3·d). So the multilayer biofilter was better than the single layer biofilter in treating H2S-contaminated gas streams. It was a kind of biofilter with longer residence time, low pressure drop, high purifying efficiency, and air movement distributed more uniformly. The removal efficiency of H2S was more than 90% during three months operation. The experiment provide some theoretical guidance for further research and engineering application.