Background & Objectives: Application of sulfate reducing bacteria to remove toxic metal contaminants from environment is considered a cost-effective and valuable method. The purpose of this study was bacterial reduction of sulfate to remove copper from synthetic wastewater under anaerobic conditions.

Methods: This experimental study was conducted in a biological reactor at anaerobic conditions. The copper was introduced into reactor at 5 to 75 mg/l. The rate of sulfate reduction and copper removal were studied at retention times of 24 hours or less. All parameters in 50 ml samples were analyzed using the standard methods for experiments of water and wastewater.

Results: After the adaptation of bacteria at different concentrations of copper, the maximum copper and sulfate removal at the optimum retention time of 24 hours were recorded 97.19 % and 98.5 %, respectively. The maximum production of H₂S at optimum operational conditions was about 117 ml/l.

Conclusion: The results showed that the reduction of sulfate and copper biological precipitation by this method is acceptable. Alkalinity generated during the process can facilitate the system for treatment of acidic wastewater containing copper sulfate.