DOI: 10.1016/j.watres.2018.08.031
Scopus记录号: 2-s2.0-85053050235
论文题名: Mystery of the high chlorine consumption in disinfecting a chemically enhanced primary saline sewage
作者: Li W. ; Zhang X. ; Li X. ; Lee J.H.W.
刊名: Water Research
ISSN: 431354
出版年: 2018
卷: 145 起始页码: 181
结束页码: 189
语种: 英语
英文关键词: Breakpoint chlorination
; Chlorine consumption
; DBPs
; Disinfection
; Wastewater treatment
Scopus关键词: Ammonia
; Chlorination
; Chlorine
; Chlorine compounds
; Disinfection
; Effluents
; Iron
; Mixing
; Sewage treatment plants
; Sulfur compounds
; Wastewater treatment
; Breakpoint
; Chemically enhanced primary treatment
; Chlorine disinfection
; DBPs
; Low concentrations
; Mixing conditions
; Simulated wastewater
; Stonecutters island sewage treatment works
; Chemicals removal (water treatment)
; ammonia
; chloride
; chlorination
; chlorine
; concentration (composition)
; disinfection
; effluent
; laboratory method
; nitrite
; nitrogen
; reduction
; sewage treatment
; wastewater treatment plant
; China
; Hong Kong
; Stonecutters Island
英文摘要: Stonecutters Island Sewage Treatment Works is one of the largest sewage treatment plants in the world and consists mainly of a chemically enhanced primary treatment (CEPT) unit and a disinfection unit. It has long been realized that most of the dosed chlorine (15 mg/L) is lost at the beginning part of the disinfection unit during disinfection of the CEPT effluent. Lab-scale tests were therefore conducted in this study to determine the causes. Because ferric chloride is used in CEPT, ferrous iron in the CEPT effluent (from the reduction of ferric iron) was initially thought to be the main chlorine consumer. However, the chlorine consumption by ferrous iron was found to be 1.2 mg/L at most. Suspended solids and sulfide also did not contribute significantly to the chlorine consumption. Batch tests were therefore conducted to evaluate the effects of mixing condition and chlorine stock solution concentration on the chlorine consumption. Less chlorine was consumed upon increased mixing. Using a high-concentration chlorine stock solution (25000 mg/L) resulted in a 3-times-higher chlorine consumption in the absence of mixing than using a low-concentration chlorine stock solution (2500 mg/L). By correlating the losses of ammonia and total nitrogen with the chlorine consumption, we hypothesized that the use of a high-concentration chlorine stock solution under poor mixing leads to a localized high ratio of chlorine to ammonia, resulting in breakpoint chlorination and an unusually excessive chlorine consumption. A novel apparatus was developed to quantify the nitrogen gas generated during chlorination of a simulated wastewater, and the mass balance of nitrogen-containing species (i.e., ammonia, nitrogen gas, nitrite and nitrate) during the chlorination was inspected. The good fit between the measured chlorine consumption and that back-calculated from nitrogen-containing species verified our hypothesis. Finally, it needs mentioning that the high chlorine consumption and the breakpoint chlorination may occur during chlorine disinfection of any sewage effluents with relatively high ammonia levels; thus it is suggested that either not-too-high concentrations of chlorine stock solutions or sufficient mixing should be applied during disinfection of the sewage effluents. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112449
Appears in Collections: 气候减缓与适应
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作者单位: Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Hong Kong; Department of Civil Engineering, The University of Hong Kong, Hong Kong
Recommended Citation:
Li W.,Zhang X.,Li X.,et al. Mystery of the high chlorine consumption in disinfecting a chemically enhanced primary saline sewage[J]. Water Research,2018-01-01,145