WANG Mu,TAN Zhen-jiao,LI Ji,et al.Influence Factors of Sodium Hypochlorite Disinfection Performance in Municipal Wastewater Treatment Plant[J].China Water & Wastewater,2021,37(1 1):22-27.
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Influence Factors of Sodium Hypochlorite Disinfection Performance in Municipal Wastewater Treatment Plant

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第37卷 Number: 1 1 Page: 22-27 Column: Date of publication: 2021-01-01
Author(s):
WANG Mu1; TAN Zhen-jiao1; LI Ji2; CHEN Jiang-jie1; ZHANG Min1; WANG Rui-jie1; WANG Yue-hong1; WANG Xiao-li1; WANG Yan2; GAO Zhi-lin3; ZHAO Zheng-hua3; LUO Guo-bing4
(1. Wuxi Public Utilities Environment Testing Research Institute Co. Ltd., Wuxi 214063, China；2. School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; 3. Wuxi Public Utilities Testing Co. Ltd., Wuxi 214073, China; 4. Wuxi City Drainage Monitoring Station, Wuxi 214011, China)
Keywords:
municipal wastewater treatment plant; disinfection; sodium hypochlorite; logarithmic removal rate; influence factor
Abstract:
Sodium hypochlorite disinfection is the most widely used disinfection method in municipal wastewater treatment plants in China. However, no consensus has been reached on the operation parameters of sodium hypochlorite (such as dosage) and its disinfection performance. In view of the above problems, the sodium hypochlorite disinfection experiment was carried out to treat the effluent from the secondary settling tank of a municipal wastewater treatment plant in accordance with first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). Logarithmic removal efficiency of fecal coliform in the effluent from the secondary settling tank was positively correlated with available chlorine dosage, contact time and temperature in the process of disinfection. ORP of the effluent after disinfection could indirectly characterize the disinfection performance, and CT values (contact time T×disinfectant residual concentration C at the end of contact time) could guide the dosage of disinfectant. Under the premise of contact time of 12 min，when available chlorine dosage was 3.67 mg/L, the logarithmic removal rate of fecal coliform could reach more than 2.5 lg, which ensured the fecal coliform count in the effluent after disinfection to reach first level A discharge standard. At this time，ORP was 578 mV, CT value of total chlorine was 7.6 mg·min/L, and CT value of free chlorine was 3.3 mg·min/L.
Last Update: 2021-01-01