Effect of pH on sulfate removal from wastewater using a bioelectrochemical system

The effects of pH on sulfate pollutant removal, power generation and microbial community were investigated using a bioelectrochemical system, which was built on acclimatized sludge with sulfate at different pHs. For the experiment, ethanol was used as the electron donor for the reduction of sulfate pollutant. In the range of pHs between 2.5 and 10.5, the optimum condition for sulfate removal from wastewater is at pH 4.5 considering the capital cost, removal efficiency, chemical oxygen demand and coulombic efficiency. The results were different from previous studies that neutral condition is suitable for sulfate-reducing bacteria to treat pollutants. According to microbial community analysis, Paludibacter sp. might play the most important role in sulfate removal at pH 4.5. Desulfuromonadaceae sp., Desulfobulbaceae sp. and Desulfovibrio sp. were inferred to make major contributions to power generation. These results could help to reduce capital cost in treating acidic sulfate-rich wastewaters.

• Effective sulfate removal at pH 4.5 using a bioelectrochemical system is obtained.
• Paludibacter sp. might play an important role in sulfate removal at pH 4.5.
• The results can help to reduce the operation cost for acidic wastewater treatment.