A Study on the Optimal Management Technology of the On-site Sodium Hypochlorite Generator for Disinfection By-products Reduction

• Published in: Daehan hwan'gyeong gonghag hoeji Vol. 44; no. 12; pp. 525 - 533
• Main Authors: Park, No-suk, Yoon, Suk-min, Park, Sang-min, Yun, Hyeon-jeong, Yun, Mi-ae, Lee, Young-joo
• Format: Journal Article
• Language: English
• Published: Korean Society of Environmental Engineers 01.12.2022
• Subjects: bromate; chlorate; free available chlorine; on-site sodium hypochlorite generator; optimal operation conditions
• ISSN: 1225-5025; 2383-7810
• DOI: 10.4491/KSEE.2022.44.12.525

Objectives : The purpose of this study is to suggest operating conditions that can minimize the disinfection by-products of sodium hypochlorite produced in on-site sodium hypochlorite generators.Methods : The characteristics of disinfection by-products were investigated by operating conditions (dissolved water type, brine concentration, temperature of electrolytic cell inflow water, pH of electrolytic cell inflow water and electrolyzer current density) using a on-site sodium hypochlorite generator(5 kg/day).Results and Discussion : The concentration of disinfection by-products (chlorate, bromate) according to the type of dissolved water was found to be high in the order of softened water > tap water > RO treated water. As the brine concentration increased, chlorate decreased and bromate increased. The optimal saline concentration was found to be 3% or more. As temperature of electrolytic cell inflow water increases,, chlorate decreases and bromate increases. The difference in the concentration of disinfection by-products(chlorate, bromate) according to the pH of electrolytic cell inflow water is not large, and the appropriate pH is determined to be about 7 when the free available chlorine and disinfection by-products are taken into account. Also, as the current density increases, the chlorate increases and bromate showed a decreasing trend.Conclusion : It has been shown that the concentration of disinfection by-products can be minimized when operating within the operating range suggested by the on-site sodium hypochlorite generator manufacturer, and some operating conditions are thought to have been suggested by the manufacturer to protect the electrolyzer cells. As the market for on-site sodium hypochorite generator gradually expands, it is expected that improved facilities will be continuously released in consideration of the stricter standards for disinfection by-products.