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H2S removal and microbial community composition in an anoxic biotrickling filter under autotrophic and mixotrophic conditions
- Khanongnuch, Ramita, Di Capua, Francesco, Lakaniemi, Aino-Maija, Rene, Eldon R., Lens, Piet N.L.
- Journal of hazardous materials 2019 v.367 pp. 397-406
- Brevundimonas, Rhodocyclales, Thiobacillus, acetates, biofilm, biofilters, biomass production, community structure, denitrifying bacteria, desulfurization, hydrogen sulfide, liquids, microbial communities, nitrate nitrogen, nitrates, organic carbon, wastewater
- Removal of H2S from gas streams using NO3−–containing synthetic wastewater was investigated in an anoxic biotrickling filter (BTF) at feed N/S ratios of 1.2–1.7 mol mol−1 with an empty bed residence time of 3.5 min and a hydraulic retention time of 115 min. During 108 days of operation under autotrophic conditions, the BTF showed a maximum elimination capacity (EC) of 19.2 g S m−3 h−1 and H2S removal efficiency (RE) >99%. When the BTF was operated under mixotrophic conditions by adding organic carbon (10.2 g acetate m−3 h−1) to the synthetic wastewater, the H2S EC decreased from 16.4 to 13.1 g S m−3 h−1, while the NO3− EC increased from 9.9 to 11.1 g NO3−–N m−3 h−1, respectively. Thiobacillus sp. (98–100% similarity) was the only sulfur–oxidizing nitrate–reducing bacterium detected in the BTF biofilm, while the increased abundance of heterotrophic denitrifiers, i.e. Brevundimonas sp. and Rhodocyclales, increased the N/S ratio during BTF operation. Residence time distribution tests showed that biomass accumulation during BTF operation reduced gas and liquid retention times by 17.1% and 83.5%, respectively.