title: Identification and characterization of steady and occluded water in drinking water distribution systems.
abstract: Deterioration and leakage of drinking water in distribution systems have been a major issue in the water industry for years, which are associated with corrosion. This paper discovers that occluded water in the scales of the pipes has an acidic environment and high concentration of iron, manganese, chloride, sulfate and nitrate, which aggravates many pipeline leakage accidents. Six types of water samples have been analyzed under the flowing and stagnant periods. Both the water in the exterior of the tubercles and stagnant water carry suspended iron particles, which explains the occurrence of "red water" when the system hydraulic conditions change. Nitrate is more concentrated in occluded water under flowing condition in comparison with that in flowing water. However, the concentration of nitrate in occluded water under stagnant condition is found to be less than that in stagnant water. A high concentration of manganese is found to exist in steady water, occluded water and stagnant water. These findings impact secondary pollution and the corrosion of pipes and containers used in drinking water distribution systems. The unique method that taking occluded water from tiny holes which were drilled from the pipes' exteriors carefully according to the positions of corrosion scales has an important contribution to research on corrosion in distribution systems. And this paper furthers our understanding and contributes to the growing body of knowledge regarding occluded environments in corrosion scales.
authors.affiliation: Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
authors.forename: Huiyan
authors.initials: H
authors.lastname: Tong
authors.affiliation: Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China. Electronic address: zhpeng@tju.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
authors.forename: Yimei
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
authors.forename: Weigao
authors.initials: W
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China. Electronic address: meili@nju.edu.cn.
authors.forename: Mei
authors.initials: M
authors.lastname: Li
mesh_terms: D003343:Corrosion; D060766:Drinking Water / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis; D008345:Manganese / Q000032:analysis; D013058:Mass Spectrometry; D009566:Nitrates / Q000032:analysis; D013431:Sulfates / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis* / Q000592:standards
chemical_list: D060766:Drinking Water; D009566:Nitrates; D013431:Sulfates; D014874:Water Pollutants, Chemical; D008345:Manganese; D007501:Iron
keywords: Corrosion mechanism; Drinking water quality; Occluded water; Secondary pollution control; Steady water