Evaluation of H2S gas removal by a biotrickling filter: Effect of oxygen dose on the performance and microbial communities

Abstract

A cost-efficient and environmentally friendly biofiltration system is essential for desulfurization to recover elemental sulfur and sulfate for extensively remediating H2S. This work investigated the H2S removal capacity, accumulation of desulfurization products, sulfur balance, microbial community, and the pathway for sulfide oxidation under different O2 doses (1%, 3%, 5%, and 10%). The results showed that the removal efficiency of H2S increased from 94.1% to 100.0% with the increase of O2 dose. At 1% O2, the elimination capacity (EC) was 5.72 ± 0.33 gH2S m–3 h–1, and about 78.13% of S0-S was generated. However, with stepwise increase of O2 concentration to 10%, the EC became 6.00 ± 0.35 gH2S m–3 h–1, and SO42–-S was the dominant product at 80.39%. Furthermore, the sulfur balance was verified by calculating the proportion of sulfur compounds (S0-S, SO42−-S, and SO32−-S) and comparing the microstructure of packing material in the biotrickling filter. Moreover, 16 S rRNA high-throughput sequencing analysis showed that the cooperation of sulfur-oxidizing bacteria in the biofiltration system was the key to the stable and efficient removal of H2S. In addition, possible reaction pathways in which H2S was transformed to S0 and SO42− were proposed.