Research On Treatment Of Odor Gas Containing Hydrogen Sulfide By Multilayer Biofilter

Odor Pollution is considered to be one of the seven pollution problems of the world. H2S-contaminated gas streams was very harmful. Using corncob and sawdust as filler, biofiltration technique for treating H2S-contaminated gas streams was investigated. The suitable technological conditions, desulfurizing-bacteria and removal kinetics have been studied in this paper. The mainly results were as follows:1.Through a series of experiments, the activated microorganisms came from the compost leachate. The desulfurizing-bacteria had a good capacity for desulfurization. The experimental results showed that the removal rate of S2- was 80% after lOh's degradation, The growth process of the desulfurizing-bacteria in different cultivation condition have been studied, the results showed that the appropriate pH value and temperatures were 4.0 and 30℃.2. Using the single layer biofilter to treat H2S-contaminated gas streams, the removal efficiency declined with the increase of the inlet concentration of H2S. In the experiment, the gas flow was 0.2m3/h. The removal rate of H2S was higher than 90% when the inlet volumetric loading rate of H2S below 144.7g(H2S)/(m3·d), and the inlet volumetric loading rate of H2S should below 144.7g(H2S)/(m3·d) when sawdust used as filler.3. Using the multilayer biofilter to treat H2S-contaminated gas streams, the factors affected the effieiency of H2S purificaiton were researched by comparing the performance of different fillers. Using corncob as filler, the removal rate of H2S was higher than 90% when the inlet hydrogen sulfide was lower than 200mg/m3. The removal rate of H2S was higher than 98% when the inlet hydrogen sulfide was lower than 60mg/m3. The multilayer biofilter had a higher removal rate of H2S than that of the single layer biofilter.4. The removal rate of each layer was studied. When the inlet hydrogen sulfide was lower than 40 mg/m3, the lower layer which was 200 mm thick removed more than 95% of the total removal rate. The removal rate of the lower layer declined with the increase of the inlet concentration of H2S, the other two layers played a major role. So we must design the height of packing layer according to the inlet concentration of H2S and purification demand in practice.5. The relation between the moisture content and the removal rate have been studied. The results showed that according to the single layer biofilter, the suitable moisture content ranged from 60% to 70% when using corncob as filler, and it ranged from 45% to 50% when using sawdust as filler. According to the the multilayer biofilter, the suitable moisture content ranged from 50% to 60% when using sawdust as filler.Using the multilayer biofilter, the suitable moisture content of the sawdust was somewhat increased. the suitable moisture content of the corncob kept invariant.6. pH value of the fillers were determined for last two months. At the beginning, pH value of the corncob was 6.5, and the sawdust was 6.9. As the time was going, pH value declined. At the end of the period, the pH value was 4 to 5. The removal rate of H2S kept still. It was suitable for the desulfurizing-bacteria growing in acid environment.