ABSTRACT

Plasma generated by high voltage discharge can be applied in drinking water or wastewater treatment. The plasma treatment of deionized and tap water was performed in an experimental unit. Electric discharge was formed in air bubble flows spreading between the electrodes. Electric potential had amplitude 33 kV, frequency 500 Hz, impulse front 8 mksec, current in electric breakdown had amplitude up to 400 A. Specific Electric Conductivity (SEC), concentrations of hydrogen ions (from pH), concentrations of total iron and sum of nitrates and nitrites in water increased with time of treatment due to formation of nitric and nitrous acids and sedimenting iron-containing particles (the tap water after 3 minutes of treatment had 8 mgN/L, 5 mgFe/L, pH = 3.6). Concentrations of other ions in the treated tap water remained approximately the same as before treatment. Optical density of water in the range from 200 to 800 nm decreased or increased with the time of treatment depending on the wavelength. SEC and fluorimetry were suggested for express-monitoring of plasma treatment efficiency.