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Biogas biodesulfurization has been successfully performed in biotrickling filters (BTFs). Nevertheless, elemental sulfur (S 0 ) generation and accumulation in the packed bed cause an increase in operating costs restricting its application. This drawback could be avoided using a gas-lift bioreactor as proposed in the present work, which allows recovery and reuse of the generated S 0 . The effect of governing operational parameters [nitrite concentration, nitrogen/sulfur (N/S) molar ratio, hydraulic residence time (HRT), pH, inlet load (IL), and gas residence time (GRT)] was studied. Results showed that no inhibition by nitrite was found at concentrations up to 760 mg N− NO 2 − L −1 . H 2 S removal efficiencies (REs) over 95% were obtained under ILs over 55 g S−H 2 S m −3 h −1 when N/S molar ratios of 1.1 mol mol −1 or above were used. A HRT of 36 h and a pH of 7.8 ± 0.05 were found to be optimal. The maximum S 0 production (99%) was obtained under an IL of 180 g S−H 2 S m −3 h −1 using a N/S molar ratio of 1.1 (RE = 98.1 ± 0.5%). A maximum elimination capacity of 194.2 ± 4.2 g S−H 2 S m −3 h −1 (RE = 83.9%) was obtained under a GRT of 41 s. Therefore, gas-lift bioreactors stand as a successful and feasible alternative to BTFs to accomplish the anoxic biodesulfurization.

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