The inactivation of E. coli and total coli bacteria during pulsed corona discharge in the river water was investigated. The bacterial suspension of volume 157 ml was polluted with E. coli and total coli with concentration of 230 cfu/100 cm 3 and 1500 cfu/100 cm 3 , respectively. The processing was conducted in a tube reactor with hollow needle-torod electrode system. The 2 min. of treatment caused decrease of total coli concentration by three orders of magnitude leaving only 3 cfu/100 cm 3 , which was E. coli. Obtained energy efficiency was 0.15 cfu/J.

An influence of iron ions presence in water contaminated with phenol on phenol degradation induced by the corona discharge in air-like gas mixture was studied. DC positive corona discharge was generated between a hollow needle, through which air with 1.5 % CO 2 flowed, and the water surface. Concentration of phenol and iron sulphate in water was 0.6 mM and 0.08 mM, respectively. It was observed that phenol degradation was not enhanced by the presence of iron ions. There was no Fenton reaction producing OH radicals, in spite of significant production of hydrogen peroxide. Instead of going into Fenton reaction with hydrogen peroxide molecules, iron ions react with ozone which is produced in gas phase and then dissolves in water.PACS : 52.80.Wq

In this work results of the laser visualization of the gas bubbles flow in a needle-to-cylinder pulsed discharge reactor filled with distilled water are presented. The experimental setup consisted of a pulsed discharge reactor, high voltage supply, CuBr laser, and Video camera. In the glass reactor bottom a stressed needle or a set of needles were placed. The grounded cylinder was set 45 mm above the needle electrode(s). The pulses of positive voltage (up to 31 kV) with a repetition rate of 50 Hz were used. A laser beam emitted from the CuBr laser was formed, using a telescope, into the laser sheet, which crossed the reactor in a selected vertical and horizontal plains. It was observed that during the positive pulsed discharge in water the bubbles production and the streamer size increased with increasing applied voltage. Large vortices generated during the discharge distributed bubbles in the whole reactor volume, providing good mixing and distribution of active species. The more needles were used, the larger number of bubbles were observed.

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