Streamer discharges for water purification

Summary form only given. Streamer discharges are considered to be an energy efficient alternative method for the biological and chemical decontamination of water. We have studied the generation of streamers in distilled and in tap water with a coaxial reactor of 50 mm diameter and 100 mm length. Voltage pulses of up to 100 kV amplitude and 500 ns duration have been applied. Electrical and optical diagnostics were used to investigate the spatial and temporal development of the streamers. With a straight wire of 75 /spl mu/m in diameter as the center electrode, an average of 3-4 streamers per cm wire length was observed. By enclosing the wire in a perforated insulating tube, a highly luminous plasma was generated in the pinhole perforations. The plasma spread along the outer surface of the tube, and served as a source of a multitude of secondary streamers. The high streamer density indicates a potential increase in bacterial and chemical decontamination efficiency over simple coaxial streamer reactors. The streamer density might be further enhanced by introducing dielectric pellets into the discharge volume. Experimental results on the bacterial decontamination effect of the various types of discharge will be presented.