Understanding the initial use stage of cement mortar lining in drinking water distribution systems:Silicon and aluminum as stability indicators  

作　　者：Qiaozhi Liu Yuan Zhuang Guiwei Li Yao Zhang Marc A.Edwards Baoyou Shi 

机构地区：[1]Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Civil and Environmental Engineering,Virginia Tech,Blacksburg,VA 24061,USA

出　　处：《Journal of Environmental Sciences》2024年第1期495-505,共11页环境科学学报（英文版）

基　　金：supported by the Beijing Municipal Science&Technology Program (No.Z201100008220003);the National Key R&D Program of China (No.2019YFD1100105)。

摘　　要：The cement mortar lining(CML)of commonly used ductile iron pipes can severely deteriorate the drinking water quality at the initial stage of use,but the behavioral characteristics of different elements release from the CML in this stage is still unclear.In this study,dynamic immersion experiments with new cement mortar lined ductile iron pipe reactors were conducted under different feed water hardness and alkalinity conditions.The results showed that the release of alkaline substances from the CML at the initial stage of use could strongly influence the pH of water,which consequently greatly impacted the release/precipitation behaviors of calcium,aluminum and silicon.The pH and aluminum concentration of the effluent water could reach 11.5 and 700μg/L within 24 hr of hydraulic retention time,respectively,under conditions of relatively lower hardness and alkalinity.Due to the pH elevation,calcium carbonate precipitation could occur even at much lower feed water alkalinity.Whereas the aluminum and silicon could keep release from the CML in soluble form at different hardness and alkalinity levels,and their release rate depended on the amount of calcium carbonate precipitation.Thus,aluminum and silicon were more suitable as indicators of the corrosion intensity at the initial stage of CML use rather than the traditional calcium carbonate precipitation potential.Appropriate feed water hardness and alkalinity levels for mitigating the initial intense corrosion of CML were proposed:hardness>40 mg/L(CaCO_(3)),alkalinity>100 mg/L(CaCO_(3)).

关 键 词：Cement mortar lining HARDNESS ALKALINITY Elemental release Drinking water supply 

分 类 号：TU991.36[建筑科学—市政工程]