Biotechnology Advances in Treatment of Air Streams Containing H2S

Hydrogen Sulfide (H2S) is an odourous, highly toxic gas commonly encountered in various commercial and municipal sectors. Three novel, laboratory-scale, Horizontal-Flow Biofilm Reactors (HFBRs) were tested for the removal of H2S gas from air streams over a 178-day trial at 10°C. Removal rates of up to 15.1 g [H2S] m(-3) h(-1) were achieved, demonstrating the HFBRs as a feasible technology for the treatment of H2S-contaminated airstreams at low temperatures. Bio-oxidation of H2S in the reactors led to the production of H(+) and sulfate (SO(2-)4) ions, resulting in the acidification of the liquid phase. Reduced removal efficiency was observed at loading rates of 15.1 g [H2S] m(-3) h(-1). NaHCO3 addition to the liquid nutrient feed (synthetic wastewater (SWW)) resulted in improved H2S removal. Bacterial diversity, which was investigated by sequencing and fingerprinting 16S rRNA genes, was low, likely due to the harsh conditions prevailing in the systems. The HFBRs were dominated by two species from the genus Acidithiobacillus and Thiobacillus. Nonetheless, there were significant differences in microbial community structure between distinct HFBR zones due to the influence of alkalinity, pH and SO4 concentrations. Despite the low temperature, this study indicates HFBRs have an excellent potential to biologically treat H2S-contaminated airstreams.

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THE REMOVAL OF H₂S FROM PROCESS AIR BY DIFFUSION INTO ACTIVATED SLUDGE

Moussavi¹,

Naddafi²,

Mesdaghinia³

et al. 2007

Environmental Technology

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Emissions of H2S from publicly owned treatment works is a serious problem, therefore collection and treatment of these emissions is essential. In this work, the performance of a bench scale activated sludge system used for the removal of H2S from foul air was investigated, and the effects of H2S concentration (5 to 50 ppm,) on COD reduction and biomass settleability were studied. After biomass acclimation, the reactor was operated in a continuous mode at a hydraulic retention time of 5 h and a mean cell residence time of 6 days. Results showed that COD and H2S removal were 93.5 and 94.5%, respectively. Furthermore, H2S concentration up to 50 ppm, did not significantly affect the COD reduction. H2S loading rates of up to 7.5 mg(H2S) g(-1)MLSS, d(-1) were treated with greater than 94% efficiency. The only adverse effect of H2S that was observed was an increase in the sludge volume index at loading rates over 4.5 mg(H2S) g(-1)MLSS d(-1), at which bulking of the sludge occurred. Overall, the results indicate that H2S at concentrations usually emitted from wastewater treatment processes (lower than 50 ppm(v)), can be efficiently treated by diffusion into activated sludge without compromising the performance of the activated sludge process.

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Biotechnology Advances in Treatment of Air Streams Containing H2S

Cited by 8 publications

References 1 publication

Application of water based nanofluids in bioscrubber for improvement of biogas sweetening in a pilot scale

Application of water based nanofluids in bioscrubber for improvement of biogas sweetening in a pilot scale

Hydrogen sulfide oxidation in novel Horizontal-Flow Biofilm Reactors dominated by an Acidithiobacillus and a Thiobacillus species

THE REMOVAL OF H₂S FROM PROCESS AIR BY DIFFUSION INTO ACTIVATED SLUDGE

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Biotechnology Advances in Treatment of Air Streams Containing H2S

Cited by 8 publications

References 1 publication

Application of water based nanofluids in bioscrubber for improvement of biogas sweetening in a pilot scale

Application of water based nanofluids in bioscrubber for improvement of biogas sweetening in a pilot scale

Hydrogen sulfide oxidation in novel Horizontal-Flow Biofilm Reactors dominated by an Acidithiobacillus and a Thiobacillus species

THE REMOVAL OF H2S FROM PROCESS AIR BY DIFFUSION INTO ACTIVATED SLUDGE

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THE REMOVAL OF H₂S FROM PROCESS AIR BY DIFFUSION INTO ACTIVATED SLUDGE