Abstract: Biological sulphate reduction is a new technology that can be used for the treatment of wastewater containing high amounts of sulphates and metals. The objective of this work was to investigate the feasibility and efficiency of biological sulphate reduction in a sulphidogenic jet loop biofilm reactor using hydrogen as electron donor. Polystyrene balls (qty: 265g, size > 2mm, density: 135 kg/m3, total surface area : 2.29 m2) were used, for the first time in this research as floating carrier material for bacterial attachment. In this jet loop reactor, high mass transfer rate between hydrogen and sulphate reducing active biomass is achieved by using a liquid jet drive. The reactor was run in mesophilc condition (340C) and a pH controller unit was fitted to maintain the reactor pH at optimum for bacterial growth and reducing the H2S toxicity.