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An industrial-scale biotrickling filter for the removal of high concentrations of H 2 S is described in this work. The system has been operating at H 2 S inlet concentrations between 1000 and 3000 ppm v at acidic conditions. A decrease of pH from 2.6 to 1.8 did not affect the biological activity inside the biofilter while reducing the water make-up consumption up to 75%. The current oxygen supply system, based on direct injection of air to the liquid phase, has demonstrated to be inefficient for a long term operation leading to elemental sulfur accumulation in the packing material (i.e. promoting clogging episodes). The present study demonstrates it is possible to partially remove (40.3%) the deposited elemental sulfur by bio-oxidation when biogas is not fed. In normal operation conditions, the implementation of an aeration system based on jet

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The present study evaluates the technical and economical feasibility of the H2S elimination from an energy-rich gas using a full-scale biotrickling filter installed in a municipal waste water treatment plant. The study analyzes the continuous operation of a 4.5 months period, treating 80 m3 h-1 of biogas with an average H2S concentration of 3000 ppmv. The bioreactor was operated at a gas contact time of 180 seconds and maximum elimination capacities of 170 g H2S m-3 h-1 were obtained without any occurrence of neither biological nor mass transfer limitation. Elemental sulfur and sulfate were the main detected byproducts of the H2S treatment. The main drawback observed during the studied period was related to the air flow supply. This caused a removal efficiency decrease and an excess of sulfur production. A comparative cost-benefit analysis of the more applied chemical oxidation processes with the biological treatment was performed. Savings chemicals indicated that the payback time of the substitution treatment was about 4.5 years. Cost savings ranged between 11000€ per year, or 2.6€ per kg H2S treated. The results of this study have shown how to solve the main operational problems detected in the proposed system and the cost-benefit analysis suggests a significant benefit by replacing the current chemical treatment by the biological alternative not only from an environmental point of view, but also from an economical perspective.