The literature highlights that sulphate-reducing bacteria need to oxidize a carbon source in order to reduce sulphates. Starting from this observation, the main objective of this project is to study if sulphate-reducing bacteria have the potential to degrade carbon pollution in horizontal subsurface flow sand filters. Two parallel horizontal sand filters have been designed. After a seeding period with wastewater coming from the wastewater treatment plant of Strasbourg, both horizontal sand filters have been fed with a synthetic influent. One of the horizontal sand filters was fed with an influent representative of a sulphate-rich carbon-polluted wastewater, in order to favour the growth of sulphate-reducing bacteria. The second one was fed with an identical influent, but without sulphates. After a maturing period, the COD reduction is about 95%, and equivalent to the one observed for the horizontal sand filter used as a reference. Though the influent of the horizontal sand filter fed with sulphates is acid, and the concentration in dissolved oxygen reaches zero, the decrease in COD is important and allows an effluent concentration inferior to 40mg/l of COD. Thus, we settled a system that is similar to an acid mine drainage, but that allows a good degradation of carbon pollution.