Removal of Hydrogen Sulfide in a Biotrickling Filter under Extremely Acidic Conditions

Hydrogen sulfide (H₂S), an extremely corrosive and toxic gas, was commonly generated by urban treatment plants, gas and oil refineries, paper and pulp industries and so on. Biofiltration, which was considered as cost-effective and environment-friendly, evoked substantial attention in recent years. In this study, a biotrickling filter filled with polypropylene pall rings was constructed, where efficient removal of H₂S under extremely acidic conditions (pH 1.0) took place. The effects of empty bed resident time (EBRT), inlet H₂S concentration, pH on the performance of the reactor were investigated. H₂S removal efficiency was consistently above 90% after a start-up period of 18 d and a maximum elimination capacity of 52.0 g/m³·h was obtained after operation for 58 d. A high removal efficiency of 100% was achieved with EBRT in the range of 13-30 s. A maximal elimination capacity of 70.2 g/m³·h was obtained with an inlet H₂S concentration of 400 mg/m³, when H₂S removal efficiency was only 73.1%. These results demonstrated that the system could be operated well under extremely low pH, which is economical and convenient for H₂S removal process where hydrogen ions were accumulated.