Results are presented from investigations of multispark electric discharge in water excited along multielectrode metal-dielectric systems with gas supply into the interelectrode gaps. The intensity distribution of discharge radiation in the region covering the biologically active soft UV (190⩽λ⩽430 nm) has been determined and the absolute number of quanta in this wavelength interval has been measured. The potentiality of the slipping surface discharge in water for its disinfection is analysed. The energy expenditure for water cleansing is estimated to be as low as ~10-4 kWh l-1.

Aims:  To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro‐organisms. Methods and Results:  Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (η ≈ 10 –4 kW h l –1 ). Conclusions:  The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. Significance and Impact of the Study:  The non‐thermal treatment method can be used for the eradication of micro‐organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

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The aim of this work was to investigate the effectiveness of a high voltage multi-spark electric discharge, with pulse energy of 1 Joule, in killing microorganisms in wastewater. Wastewater from primary treated effluent arising from domestic and industrial sources was abstracted for continuous pulsed discharge disinfection. The wastewater contained a large mixed population of microorganisms (approximately 10(7) CFU ml(-1) [10(9) CFU 100 ml(-1)] total aerobic heterotrophic bacteria) including vegetative cells and spores. The electrical conductivity of the wastewater ranged from 900-1400 microS cm(-1) and it was shown that a specific energy of 1.25-1.5 J cm(-3) was required to achieve 1 log reduction in bacterial (faecal coliforms/total aerobic heterotrophs) content. This is higher than that previously shown to reduce the population of E. coli in tap water of low conductivity, demonstrating the role of total wastewater constituents, including dissolved and particulate substances, water colour and the presence of microbial spores, in effective disinfection. The system can be engineered to eradicate microbial populations to levels governed by legislation by increasing treatment time or energy input.