Experimental Research on the Sterilization of Escherichia Coli and Bacillus Subtilis in Drinking Water by Dielectric Barrier Discharge

Abstract

The bactericidal effect on the representative type of Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge (DBD) advanced oxidation technology. The sterilizing rates under different conditions of reaction time t, input voltage V , pH value, and initial concentration of bacteria C0 were investigated to figure out the optimum sterilization conditions. Our observations and comparisons of cell morphology alteration by scanning electron microscopy and transmission electron microscopy revealed the sterilization mechanisms. The results showed that the sterilizing rate increased obviously with the extension of reaction time t and the rise of input voltage V . The optimal sterilization effect was achieved when the pH value was 7.1. As the initial concentration of bacteria rose, the sterilizing rate decreased. When the input voltage was 2.2 kV and the initial concentration of bacteria was relatively low, the sterilizing rate almost reached 100% after a certain treatment time in neutral aqueous solution. The reasons for the great damage of cell structure and the killing of bacteria are the oxidation of O3, OH and the accumulation of active species produced by DBD. The article provides a certain theoretical and experimental basis for DBD application in water pollution treatment.

The Applications of Plasma Gas Injection for Pollutants Treatment

“…In addition to inactivating algae, this novel plasma gas injection is successfully used to remove pathogenic bacteria [72], antibiotics [73], and organic pollutants [74], [75] in drinking water, and the details are described in Table II. Furthermore, to achieve its broad use in drinking water treatment, it is necessary to investigate the treatment impact of plasma gas injection on composite pollutants in the real water sources.…”

Discharge characteristics and reactive species production of unipolar and bipolar nanosecond pulsed gas–liquid discharge generated in atmospheric N2

“…Recently, nanosecond pulsed gas-liquid discharge (NPG-LD) with dielectric-free electrode configuration in atmospheric pressure has been widely used in many applications, including sterilization [1], water purification [2][3][4], biomedicine [5], and material treatment [6]. Compared with the sinusoidal discharge, the discharges driven by nanosecond pulse power supply are prone to cause lower heat and higher energy efficiency for producing reactive species [7][8][9].…”

Soft switching circuit to improve efficiency of all solid-state Marx modulator for DBDs

“…Dielectric barrier discharges (DBDs) have been applied in a variety of modern pulsed power applications, such as liquid food sterilization, water decontamination and air pollution control [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. DBDs are traditionally excited by high voltage and high frequency sinusoidal supply [16][17][18][19][20][21][22].…”