中国南北两城市饮用水水质化学稳定性对比研究

Comparison of Drinking Water Quality Chemical Stability between a Northern City and a Southern City in China

水质化学稳定性是表征饮用水安全的重要指标之一。基于我国南北两座城市5年间(2013年—2017年)出厂水和管网水的水质监测数据,采用Langelier饱和指数(IL)、Ryznar稳定指数(IR)、侵蚀指数(AI)和拉森比率(LR)综合分析南北两市水质化学稳定性的异同。南北供水系统水质化学稳定性与水温、pH、总硬度等常规水质指标存在相关性。北方A市IL为-0.47~0.97、IR为6.26~8.33,春夏水质具有化学稳定或结垢特性,秋冬水质具有轻度腐蚀特性;南方B市IL为-2.89~-1.99、IR为10.96~12.34,全年呈严重腐蚀倾向;AI值和LR值进一步表明两市的水质对石棉水泥管和金属管均具有侵蚀和腐蚀特性。因此,控制供水系统水质的化学稳定可有效保障供水安全。

The chemical stability of water quality is one of the most important indicators to characterize the safety of drinking water.Based on the water quality monitoring data of product water and pipe network water from two Chinese cities (city A in the north and city B in the south) during the past 5years (2013-2017),the Langelier saturation index (IL),Ryznar stability index (IR),erosion index (AI) and Larson ratio (LR) were used to comprehensively analyze the differences and similarities of water quality chemical stability between the two cities.The water quality chemical stability of drinking water from the north and south water supply systems was correlated with conventional water quality indicators such as water temperature,pH and total hardness.In city A,the values of ILand IRwere in the range of-0.47-0.97 and 6.26-8.33,respectively.The water quality in spring and summer was chemically stable or showed a tendency of scaling,while the water quality in autumn and winter was mildly corrosive.In city B,the value of ILwas between-2.89 and-1.99,and that of IRwas between 10.96 and 12.34,suggesting that the water quality showed a tendency of serious corrosion throughout the year.The values of AI and LR further indicated that the water quality of the two cities was erosive and corrosive for both asbestoscement pipe and metal pipe.Therefore,controlling the chemical stability of water quality in water supply systems can effectively guarantee the safety of water supply.