Simultaneous removal of carbon disulfide and hydrogen sulfide from viscose fibre waste gas with a biotrickling filter in pilot scale

Abstract

A biotrickling filter (BTF) inoculated with concentrated activated sludge possessing highly efficient degrading strains was investigated on a pilot-scale for the treatment of viscose fibre waste gas containing carbon disulfide (CS2) and hydrogen sulfide (H2S). The BTF had a quick start-up period, with 90.6% and 98.2% removal of CS2 and H2S, respectively, from the 18th day of acclimation. When the influent concentration was increased from 145 mg m−3 to 1912 mg m−3, steady removal efficiencies (REs) of above 70% for CS2 and 90% for H2S were achieved for the entire operation, with maximum elimination capacities (ECs) of 122.7 g m−3 h−1and 108.2 g m−3 h−1 for CS2 and H2S, respectively. The results showed that H2S was preferentially degraded by BTF, owing to hydrophilic H2S having a low Henry coefficient, which allowed it to adsorb on the biofilm surface more easily and made its biodegradation more favorable. The pH significantly affected the REs of CS2 and H2S, which decreased from 81% to 52% and from 95% to 73%, respectively, with a pH increase from 2 to 8, while sulfate accumulation did not significantly affect the pollutant REs. A tolerance experiment showed that BTF was resistant to large fluctuations in CS2 and H2S concentrations, with a RE of 80% recovered in only 2 days. Microbial diversity analysis showed that Acidithiobacillus, Acidiphilium, and Metallibacterium had higher relative abundances at the genus level, and remained persistent throughout the operation, implying that these strains played an important role in the simultaneous removal of CS2 and H2S from waste gas.