Biofiltration of waste gas containing sulfide hydrogen and toluene

A laboratory-scale biofilter was used to treat waste gas containing sulfide hydrogen and toluene. Its performance, transformation mechanisms of substances and microbiological characteristics were investigated in this study. The inlet concentrations of sulfide hydrogen and toluene varied from 30~300 mg/m³ and the inlet air flow rate was 420 L/h, equivalent to empty bed residence time of 40s. The experimental results showed that both sulfide hydrogen and toluene can be efficiently removed in the biofilter. Removal efficiency of above 93.1% for sulfide hydrogen and above 85.6% for toluene can be obtained. The main products obtained in the biodegradation process of sulfide hydrogen was sulphate and elemental sulphur, while their percentages were different at various inlet loading rates of sulfide hydrogen. There was a strong correlation between the CO₂ production and inlet toluene concentration. The results in microbial analysis had proven that both fungi and acidophilic thiobacilli were dominant in the biofilter in stable operation.