Bromate Free Disinfection of Drinking Water using a High Voltage Impulse (HVI) Technique

Ozonation for the purpose of disinfection of drinking water usually produces various kinds of disinfection byproducts (DBPs). Among the DBPs, bromate (BrO
₃
^-
) is notorious for its potential carcinogenic nature. World health organization (WHO) limits the bromate to 10 ppb in drinking water. To reduce this bromate formation during the disinfection processes, a high voltage impulse (HVI) technique was applied in this study. HVI has been used as one of disinfection process for non-thermal sterilization of foods. The HVI system consisted of power supply, high voltage generator, capacitors and impulse generator. HVI with 10 to 20 kV/cm of electric fields was introduced to sample waters in order to monitor if bromates are formed or not. As the precursor of bromate, i.e., bromide (Br-) spiked into the sample waters by 1,000 ppb, bromate was not generated at all times, indicating that the bromate formation was completely inhibited. A model microorganism, Escherichia coli is inoculated to the sample waters to test the disinfection efficiency. More than 2-log reduction (99%) of E.coli was achieved after HVI treatment with 20 kV/cm, 100 Hz, 4 μs pulse width. Consequently, HVI technique could be used for alternative strategy for bromate free-disinfection procedure for water disinfection.