Experimental Study On Sewage Disinfection Of High-voltage Electrostatic Field

High-voltage electrostatic field technology is a new sewage disinfection technique, developed in the process that the electrostatic field technology was applied in the fouling control and removal of industrial circulation water. And it takes advantages in its wide application water quality range, convenient management, low operation cost, as well as without secondary contamination. However, the disinfection efficiency results were various in the former studies on high-voltage electrostatic field disinfection technology, most of the explanation on disinfection mechanism were theoretically speculated, so that the exact mechanisms have been yet to be fully understood.The aim of this paper is to probe into the mechanism of high-voltage electrostatic sewage disinfection, according to the results that are obtained from high-voltage electrostatic field disinfection experimentation, including the inactivation rule of fecal coliform and the physico-chemical parameter variation of treated sample.The obtained results show that, when high-voltage electrostatic fields acts on the sample in two insulation plates, the concentration of fecal coliform is always below the original concentration apparently, and the inactivation rate is between 40%⁹5%, no matter how high the electric field intensity is, with or without aeration. The inactivation rule of fecal coli in high-voltage electrostatic field disinfection reactor reveals that: in the first 10mins, the magnitude of fecal coliform decreases and the inactivation rate increases sharply, reaches the peak value during 15²0mins, then begins to fall, and finally retains a stable level at 70% around.In the high-voltage electrostatic field disinfection reactor, the pH value and the electrical conductivity of treated sample change with aeration, but have no correlation with electric field. Under the condition with aeration, with the prolonging of treatment time, the pH value increases but the electrical conductivity declines.High-voltage electrostatic field has some auxiliary function on the decoloration of methylene-blue, and the decolorizing efficiency without aeration is far below than with aeration.According to the inactivation rule of fecal coliform and the decolorizing experimentation of methylene-blue, it can be speculated that the concentration of reactive oxygen species such as superoxide anion radical O₂^-·and hydroxyl radical·OH, forming in high-voltage electrostatic field, are not high, and have limit effects on life activity of fecal coliform. The charge layer, which forms on the interface between the treated sample and the disinfection reactor due to the external high-voltage electrostatic field, is the mainly reason of inactivation effect. When the fecal coliform in the treated sample enter into the charge layer, they devitalize or lose their reproductive ability for their metabolism activities can not be carried out normally.