中文摘要：

针对水源切换过程中由于水质化学组分变化可能引起管壁铁腐蚀产物释放而导致管网“黄水”的问题，从北方某市的实际管网中挖取了管垢类型不同的原通混合水和通地下水的管段，分别搭建了循环式管网模拟系统，研究了硫酸根、溶解氧和余氯对管网铁释放的影响。结果表明：管段内壁的腐蚀产物特征对管网铁释放有重要的影响。增加进水硫酸根浓度，系统铁释放均有所增加。原通混合水的管段由于其管垢厚且较稳定，对硫酸根具有较好的耐受性；而原通地下水的管段管垢薄且稳定性较差，铁的释放受硫酸根影响较大。增加水中溶解氧含量对铁的释放具有明显抑制作用，但当溶解氧超过一定值时，其抑制作用反而降低。适当调节进水余氯浓度对铁释放也具有一定的抑制作用，但不同管垢类型对应的最佳余氯浓度不同。

英文摘要：

To understand the processes of iron corrosion by-products release and the consequent red water problems caused by the variation of water chemical composition under water source switch con- dition, east iron pipes with different water supply sources and different corrosion scale characteristics were harvested from two sites of existing water distribution system in a northern China city, and two pipe-loop distribution systems were established. The effects of sulphate, dissolved oxygen （DO） and residual chlo- rine concentrations on iron release were investigated. The results showed that the characteristics of corro- sion scales had significant effect on iron release. The corrosion scales on pipes transporting blended water were thicker and more stable, while those on pipes transporting groundwater were thinner and less stable With the increase of sulfate concentration, the effluent concentrations of total iron were both increased in the two pipe-loops. However, the iron release was much more serious in the pipes transporting groundwa- ter than that in the pipes transporting blended water. Increasing DO concentration could significantly in- hibit iron release, but further increase of DO to a specific value resulted in iron release increase. Adjus- ting residual chlorine concentration could inhibit iron release, but different corrosion scales exhibited dif- ferent optimal chlorine concentrations.