Because of the difficulty in disposing bioleaching solutions of nickel ore, an alternative remediation treatment, the selective precipitation of metals using H2S produced biologically by sulfate-reducing bacteria (SRB), has attracted extensive attention. SRB oxidize some carbon compounds anaerobically by reducing sulfate, in which electron donors are essential for the growth of SRB and the efficiency of biological sulfate reduction process. In this paper, influence of some electron donors on the growth and activity of SRB was studied. The carbon compounds tested included organic acids, alcohols, volatile fatty acid salts and carbohydrates. Results showed that sulfate-reducing activity decreases in the order of organic acids, volatile fatty acid salts, alcohols and carbohydrates. Considering the rate of sulfate removal and operating cost, the use of formic acid as an energy source in our experiments was found to be the most effective, resulting in 97% sulfate removal. (C) 2012 Elsevier B.V. All rights reserved.