Treatment of sulfate-rich and low pH wastewater by sulfate reducing bacteria with iron shavings in a laboratory

Sulfate-rich wastewater is an indirect threat to the environment especially at low pH. Sulfate reducing bacteria (SRB) could use sulfate as the terminal electron acceptor for the degradation of organic compounds and hydrogen transferring SO42- to H2S. However their acute sensitivity to acidity leads to a greatest limitation of SRB applied in such wastewater treatment. With the addition of iron shavings SRB could adapt to such an acidic environment, and 57.97, 55.05 and 14.35% of SO42- was reduced at pH 5, pH 4 and pH 3, respectively. Nevertheless it would be inhibited in too acidic an environment. The behavior of SRB after inoculation in acidic synthetic wastewater with and without iron shavings is presented, and some glutinous substances were generated in the experiments at pH 4 with SRB culture and iron shavings.