Hydrogen sulphide removal from air by biotrickling filter using open-pore polyurethane foam as a carrier

• A biotrickling filter was studied for H2S removal using Thiobacillus denitrificans.
• The best biofilter performance was achieved in the pH range from 7.6 to 8.5.
• The sulphate concentration affected the microorganisms from 16.8 g L−1.
• The presence of other bacteria did not diminish the sulphur oxidation capacity.

A study was conducted on H2S removal in a biotrickling filter packed with open-pore polyurethane foam. Thiobacillus denitrificans was used as inoculum and a mixed culture population was developed during the process. The inhibitory effect of sulphate concentration (1.8–16.8 g L−1), pH (6.9–8.6), trickling liquid velocity (TLV, 9.1–22.8 m h−1), H2S inlet concentration (20–157 ppmv) and the empty bed residence time (EBRT, 9–57 s) on the H2S removal efficiency (RE) were thoroughly investigated. An increase in pH from 6.9 to 8.5 led to a corresponding increase in H2S removal. In addition, an inhibitory effect of sulphate concentration was observed from 16.8 g L−1 and the maximum elimination capacity was found to be 22 gS m−3 h−1 (RE 98%). The RE was constant (98.8 ± 0.30%) for EBRT ≥ 16 s, but a decrease in the EBRT from 16 to 9 s led to a corresponding decrease in RE from 98.2 to 89.6% for a TLV of 9.1 m h−1 and from 97.9 to 94.9% for a TLV of 22.8 m h−1 (inlet load of 11.0 ± 0.2 gS m−3 h−1). The sulphur oxidation capacity in the biotrickling filter was not diminished by the presence of other bacteria.