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Abatement of dimethyl sulfide using anoxic biotrickling filter

Shihab, Mohammed Salim, Akmirza, Ilker, Mhemid, Rasha Khalid, Türker, Mustafa, Alp, Kadir
Journal of chemical technology and biotechnology 2019 v.94 no.7 pp. 2274-2283
alpha-Proteobacteria, anaerobic conditions, bacterial communities, biodegradation, biofilters, biotransformation, denitrification, dimethyl sulfide, liquids, mass transfer, nitrates, nitrogen, oxidation, sulfates, sulfur, thermodynamics, wastes
BACKGROUND: This study aimed to use a lab‐scale anoxic biotrickling filter (ABTF) for the bioconversion of dimethyl sulfide (DMS) gas to produce less harmful byproducts, i.e. elemental sulfur and/or sulfate. It examined the exploitation of nitrate as an electron acceptor in the oxidation of malodorous DMS‐containing gas in combination with other parameters: gas/liquid (G/L) ratio (40, 60, 80, 100, 150), empty bed residence time (EBRT) (10, 30, 60, 90, 120 s) and inlet loading (IL) (9, 18, 48, 90 g m⁻³ h⁻¹). RESULTS: Thermodynamic analysis and half‐reactions showed that at DMS/NO₃⁻ molar yield ratios 0.75 and 0.34, elemental sulfur and sulfate were the main metabolic products respectively. Overall, 58% of the sulfur element in DMS was bioconverted to elemental sulfur. Mass balance calculations revealed high denitrification efficiency, i.e. 52.7% of inlet NO₃⁻ was converted to N₂. The optimal EBRT was found as 30 s (corresponding to removal efficiency (RE) 89%) for inlet concentration 150 mg m⁻³ and as 60 s (corresponding to RE 78%) for inlet concentration 1500 mg m⁻³. However, the maximum elimination capacity (EC) was 70.3 g m⁻³ h⁻¹ at EBRT 60 s and G/L ratio 80. The relative abundance of bacterial communities was dominated by Proteobacteria (56.1%) and Alphaproteobacteria (27.3%) at phylum and class levels respectively. CONCLUSION: The study revealed that ABTF has a reliable biodegradation capacity in DMS oxidation under anoxic conditions; however, process improvement on mass transfer enhancement for low waste gas concentrations is still required. © 2019 Society of Chemical Industry