Removal of odorous sulphur compounds from industrial gases by biotrickling filters

  • Vincenzo Torretta Università degli Studi dell’Insubria
  • Marco Schiavon Università degli Studi di Trento
  • Enrico Anselmo Papa Università degli Studi dell’Insubria
  • Paolo Caruson Air Clean Srl, Rho
  • Andrea G Capodaglio University of Pavia
Keywords: hydrogen sulphide, odor abatement, phosphoric acid production.


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 (H2S), sulphur dioxide (SO2) and dimethyl sulphide (DMS) from the phosphoric acid reactor’s exhaust air current. Concentrations of H2S, SO2 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 H2S 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 H2S, SO2 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.

Author Biographies

Vincenzo Torretta, Università degli Studi dell’Insubria

Prof. Vincenzo Torretta works at the University of Insubria of Varese (Italy). His work focuses on air pollution control technologies, waste treatment and energy recovery and environmental impact assessment. He has been author and co-author of several ISI/Scopus-indexed publications.

Marco Schiavon, Università degli Studi di Trento

Marco Schiavon is a PhD candidate at the University of Trento (Italy). His work focuses on air pollution control technologies, air pollution modeling and human exposure assessment. He has been author and co-author of ISI/Scopus-indexed publications on these topics since 2012.

Enrico Anselmo Papa, Università degli Studi dell’Insubria

Prof. Enrico Anselmo Papa works at the University of Insubria, Varese (Italy). His work focuses on technical structures and energy production.

Paolo Caruson, Air Clean Srl, Rho

Dr. Paolo Caruson is the owner and general director of AirClean, leader firm in the field of the treatment of gaseous emissions produced by the municipal wastewater and municipal solid waste treatment plants, in particular by biological systems and adsorbers. He is involved in applied researches thanks to a cooperation with the Universities of Trento and Varese.

Andrea G Capodaglio, University of Pavia

Professor of Environmental Engineering at the University of Pavia (Italy). Holds a MSc cum Laude from the University of Pavia and a PhD in Environmental ngineering from Marquette University in Milwaukee, USA.