Large volume discharges in water and application to sludge treatment

Summary form only given. Recent advantages in the pulsed power have opened a new field of bio- and chemical electronics. Nonthermal plasmas using streamer discharges in gases have found an extensive use for flue gas cleaning and ozone generation. The recent extension in the use of such discharges in a liquid medium such as water and sewage offers new and promising ecological applications of pulsed electric power. The discharges in water and aqueous solutions are efficient in the creation of a variety of effects as shock waves, ultraviolet radiation, high electric fields, and especially formation of chemically active species acting on biological cells and chemical compounds dissolved in water. The studies of the water treatment by streamer discharges have been carried out usually in rod-to-plane electrode configuration and recently in disk-to-ring one. In order to achieve the high efficient water treatment, the production of a large volume streamer discharges has been requested. In this study, streamer discharges with a large volume are produced successfully, and those are applied to the treatment of surplus sludge. Two kinds of electrode configurations were used such as the rod and cylindrical electrodes with a length of 15 cm, an inner diameter of 9 cm and a rod diameter of 1 mm, and the rod and plane electrodes with a length of 15 cm and gap separations of 25, 35, 45, 55 mm.