硫酸根浓度突变对给水管网铁释放的影响

Effect of sulphate concentration change on iron release in drinking water distribution systems

针对水源频繁切换造成原水水质硫酸根质量浓度突变对给水管网铁释放的影响开展试验研究。选取北京市城区3个不同地区的管段,设计并制作管段模拟反应器,比较分析不同硫酸根质量浓度水质条件下、不同地区管段的铁释放情况。结果表明:硫酸根质量浓度的大幅增加可导致黄水问题。给水管网铁释放量与硫酸根质量浓度具有显著相关性,当硫酸根质量浓度从25mg/L增加到180mg/L,相应的Larson指数从0.35增加到1.40时,8h滞留时间后管段出水浊度、色度的最大增加值分别约为6NTU和50度,总铁释放速率最大增加约2.00mg/(m2.h)。由此,确定了水源切换条件下,硫酸根和Larson指数对管垢铁释放的控制指标:硫酸根质量浓度<75mg/L,Larson指数<0.70。在此条件下,管网水主要水质指标(总铁质量浓度、浊度和色度)基本达标。

This study investigated the effect of sulphate concentration changes on the iron release in a drinking water distribution system caused frequently switching of the water source.The rates of iron release from corrosion scale for different water sources were analyzed with pipe section reactors designed to simulate the distribution system flow mode.The results showed that the sulphate concentration was the dominant factor that led to red water.The iron release rate from the corrosion scale correlated well with the sulphate concentration with a sulphate concentration increase from 25mg / L to 180mg / L accompanied by a Larson ratio increase from about 0.35to 1.40.The turbidity in the pipe section reactors increased 6NTU after 8h,the color increased 50degrees and the iron release rate increased 2.00mg /（m 2.h）.These results indicate that the sulphate concentration should be lower than 75mg / L and the Larson Ratio should be controlled to less than 0.70for the water quality in the distribution system to meet the Chinese drinking water quality standard.Based on these results,t was suggested to be and controlled less than 0.70in order that in meet the standard of drinking in China.