Electrochemical disinfection has been shown to be an efficient method with a shortrequired contact time for treatment of drinking water supplies, industrial raw water supplies, liquid foodstuffs, and wastewater effluents. In the present work, the electrochemical disinfection of saline water contaminated with bacteria was investigated in chloride-containing solutions using Sb-doped Sn-W-oxide anodes. The influence of current density, bacterial load, initial chloride concentration, solution pH, and the type of bacteria (E. coli D21, E. coli O157:H7, and E. faecalis) on disinfection efficacy was systematically examined. The impact of natural organic matter and a radical scavenger on the disinfection process was also examined. The electrochemical system was highly effective in bacterial inactivation for a 0.1 M NaCl solution contaminated with ∼10 CFU/mL bacteria by applying a current density ≥1 mA/cm through the cell.100% inactivation of E. coli D21 was achieved with a contact time of less than 60 s and power consumption of 48 Wh/m, by applying a current density of 6 mA/cm in a 0.1 M NaCl solution contaminated with ∼10 CFU/mL. Reactive chlorine species as well as reactive oxygen species (e.g. hydroxyl radicals) generated in situ during the electrochemical process were determined to be responsible for inactivation of bacteria.

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The prediction of mass-transfer rates into and from moving drops in the liquid−liquid systems has usually used the well-known Whitman two-film theory approach. According to the latter, the total resistance to mass transfer resides on each side of the interface and is described by the individual film mass-transfer coefficients for the continuous and dispersed phases in the absence of surface-active agents (contaminants). In the present work, the same approach has been used to model the excess mass-transfer resistance exerted by surface-active agents in the continuous phase. To achieve this goal, an experimental investigation has been conducted on the mass transfer into and from single drops for the chemical test system, n-butanol−succinic acid−water, recommended by the European Federation of Chemical Engineering (EFCE) in the presence and absence of the anionic surfactant, sodium dodecyl sulfate (SDS). The influence of the latter on the drop size, drop contact time, extraction fraction, viscosity of the continuous phase, and interfacial tension as well as the overall mass-transfer coefficients for both mass-transfer directions has been investigated. On the basis of the experimental results obtained for both mass-transfer directions, the excess mass-transfer resistance exerted by the surfactant has been correlated in terms of drop Reynolds numbers for the clean and contaminated chemical systems.

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