Effects of different applied electric currents on nitrate removal using the biofilm-electrode reactor

Nitrate enrichment in groundwater is a worldwide phenomenon, and the removal of nitrate from groundwater has raised ever-increasing concerns due to severe impacts of nitrate on human and animal health. A bioelectrochemical method for treatment of simulated nitrate-contaminated groundwater was investigated using a biofilm-electrode reactor (BER). Effects of different currents on the transformation of nitrate to nitrogen were investigated. The nitrate removal efficiency was dependent on the current. When the current was lower than 78mA, the nitrate removal efficiency was linearly related to the current, and a portion of the nitrate was transformed to nitrite or ammonium. The maximum nitrate removal efficiency 87% was achieved at the current of 78 mA and the given operation condition. The BER could be operated efficiently at the current of 78mA, but further increase the current did not offer significant performance promotion.