Elevated Concentration of Nitrate Ions in Water Through Direct Treatment by Dielectric Barrier Discharge

Direct treatment of water by dielectric barrier discharge plasma with pulse repetition rates in the range of 2.5-4 kHz and microsecond rise time scale was used to treat samples of water for up to 10 min. Very high concentration of nitrate ions was measured by ion chromatography, and explained by the plasma generator's operating parameters. It is shown that electrical conductivity increases and pH decreases with treatment time. These effects are enhanced at higher pulse repetition rates of the plasma discharge, provided that the power supply linearly scales power with output frequency. An increase in electrical conductivity of the treated water is in accordance with the concentration of produced nitrate ions and pH decrease.