Removal of H₂S in an extremely acidic-biotrickling filter: Evaluation of removal performance and characterization of microbial communities

A cost-efficient, environmentally friendly, and extremely acidic biotrickling filter is essential for desulfurization to recover elemental sulfur and sulfate for extensively remediating H2S. The present study investigated the H2S removal capacity, accumulation of desulfurization products, sulfur balance, microbial community, and the H2S biodegradation kinetics. The results showed that when the empty bed retention time (EBRT) decreased from 180 s to 60 s, the removal efficiency of H2S decreased from 100% to 95.4%, and the elimination capacity increased from 18.0 +/- 1.3-51.5 +/- 3.2 gH(2)S m(-3) h(-1). Furthermore, with the increase of EBRT, the proportion of SO42--S in the biodesulfurization products gradually decreased from 74.83% to 38.71%, whereas that of S-0-S increased from 16.04% to 53.30%. The content of polysaccharide (PS), protein (PN), and the change of PN/PS values during the H2S removal process were studied. Moreover, 16 S rRNA high-throughput sequencing analysis showed that Acidithiobacillus, Thiobacillus, Sulfuricurvum, and Sulfobacillus were the main genera in the removal of H2S, and their total abundance was higher than 68.00%. In addition, the system viability and robustness were proved by shock loads and starvation regimes.