A pilot plant for the treatment of Sulphur-based odorous gases was installed in a line of a phosphoric acid plant located in Skhira, Tunisia. The air pollution control system train consisted of a first stage, including a chemical scrubber operating with an alkaline solution containing caustic soda, followed by a two-stage biotrickling filter (BTF) filled with Mytilus edulis shells. This study evaluated the performance of the dual-stage BTF in removing hydrogen sulphide (H 2 S), sulphur dioxide (SO 2 ) and dimethyl sulphide (DMS) from the phosphoric acid reactor's exhaust air current. Concentrations of H 2 S, SO 2 and DMS at the inlet of the two-stage BTF were 10-30 ppm, < 1-20 ppm and 16-30 ppm, respectively. All of the respective concentrations at the outlet of the biological step were < 1 ppm, except for the H 2 S in the outlet during the first day of operation (10 ppm). Removal efficiencies were generally higher than 95% for all compounds, and remained high even with an increase of the off-gas flow rate. Mass-removal capacity was at least 2.0 g m -3 h -1 , 0.5 g m -3 h -1 and 6.2 g m -3 h -1 , for H 2 S, SO 2 and DMS, respectively. The removal efficiencies of the process were satisfactory, especially considering the already low inlet concentrations, due to the high quality of the raw phosphate used.Keywords: hydrogen sulphide, odor abatement, phosphoric acid production. Remoção de odores de compostos sulforosos de gases industriais por filtros biotrickling RESUMOUma estação piloto para o tratamento de gases odoríferos à base de enxofre foi instalado em uma linha de uma fábrica de ácido fosfórico localizada em Skhira (Tunísia). A estação piloto é constituída por um primeiro estágio que inclui um scrubber químico que usa uma e 6,2 g m -3 h -1 , respectivamente. Apesar das baixas concentrações de entrada, principalmente devidas à alta qualidade do fosfato bruto, a instalação piloto mostrou resultados satisfatórios, tendo em vista o seu redimensionamento e a sua aplicação a uma escala maior.Palavras-chave: abatimento de odores, ácido sulfídrico, produção de ácido fosfórico.