农村供水系统不同贮水材质水质变化特性分析

针对西部地区农村供水系统管线长、用水量小,水在调节池中停留时间较长而易造成供水系统二次污染的问题,选取工程上常用的混凝土、瓷砖、塑料和不锈钢材质,分别研究了不同环境条件下各贮水材质水体中余氯、pH、电导率和溶解氧等水质参数随时间的变化特征。结果表明:一定温度下不同材质调节池中,贮存水余氯衰减系数由大到小依次为混凝土、塑料、瓷砖、不锈钢;水体pH值变化也较为明显,其中混凝土及瓷砖内壁调节池pH值随储存时间增加呈现明显的上升趋势,不锈钢材质pH上升趋势平缓,而塑料材质pH值未发生显著变化;混凝土、瓷砖及不锈钢材质蓄水池电导率在初始阶段随时间的变化上升较快,而在后期随时间的变化趋势较为平稳;混凝土及不锈钢材质调节池溶解氧随时间的变化较为平稳,而瓷砖及塑料材质调节池溶解氧随时间的变化有升高的趋势。通过本研究进一步明确了不同材质调节池对水质的影响及其随环境因素变化的时间效应,以期为农村供水系统规划设计及运行管理提供一定参考。

Changes of Water Quality in Regulation Tanks Made of Different Materials in Rural Water Supply System

The rural water supply in west China is facing with problems such as long transfer distance, small flow, and secondary pollution caused by long time stay of water in the regulation tank. In order to explore the impact of regulation tank made of different materials on water quality, we tested the variations of four water quality indicators (residual chlorine, pH, conductivity and dissolved oxygen) in different tanks made of concrete, tile, plastics and stainless steel, respectively. The results show that at given temperature, the attenuation coefficient of residual chlorine in concrete tank is the largest, followed by plastic, tile and stainless steel. The pH value also changes obviously: the pH value of water in concrete and tile regulation tanks shows an obvious rising trend with the increase of storage time, while in stainless steel tank the pH value increases gently, and in plastic tank the pH value does not change significantly. The water conductivity in concrete, tile and stainless steel tanks increases with time rapidly in the early stage, but the change becomes stable later. The variations of dissolved oxygen in concrete and stainless steel tanks are relatively stable, while in tile and plastic tanks, dissolved oxygen shows a trend of increasing. The effect of different tank materials on water quality and the variation of water quality with environmental factors are obtained. It could be a reference for the design, operation and management of rural water supply system.