Fresh water disinfection by pulsed low electric field

In this paper, we describe a pulsed low electric field process for water disinfection. Electric intensity of 0.6–1.7 kV cm−1 is applied. Experiments are performed with a 1.2 L axis-cylinder reactor. A bipolar pulsed power source with pulsed width of 25 μs and frequency of 100–3000 Hz is used. Water conductivity of 3–200 μs cm−1 is investigated, which can significantly affect pulsed voltage-current waveforms and injected energy. Energy per pulse rises with increased water conductivity. The initial E. Coli density and water conductivity are two major factors influencing the disinfection. No disinfection effect is performed with deionized water of 3 μs cm−1. When water conductivity is 25 μs cm−1 and bacteria density is 104–106 cfu ml−1, significant disinfection effect is observed. More than 99% of the cells can be disinfected with an energy density of less than 70 J ml−1, while water temperature is below 30 °C.