Pilot-scale chemical-biological system for efficient H₂S removal from biogas

A pilot-scale chemical-biological process was performed efficiently to remove corrosive H₂S from biogas. Consecutive 356-d livestock biogas purification was conducted at various H₂S loading rates. The average inlet H₂S concentration was 3542ppm, and a removal efficiency of 95% was achieved with gas retention time of 288s. This system showed robust performance during operation with stable parameters. Purified biogas with an average of 59% CH₄ was collected for power production. Moreover, 28.3kWh of power was produced by using a 30kW biogas generator under 300LPM biogas flow rate. During the 30-d shut down test, the jarosite formation resulted in pH decrease and appearance of Leptospirillum sp. and Sulfobacillus sp. in the bioreactor. However, the cell density of the inoculated Acidithiobacillus ferrooxidans was maintained above 5×10⁷CFU/g-AC during long-term operation. Thus, given the successful H₂S elimination, the chemical-biological process is a feasible system for biogas purification.