Cause analysis and control technology pilot study of yellow water in a groundwater water supply network in a city in northwest China
With the increase of the service life of water supply pipe,the pipe network is gradu-ally aging,and the problem of chemical stability of pipe network is increasingly prominent.In or-der to solve the yellow water problem in a water supply network with high alkalinity groundwater in a city of northwest China and ensure the safety of water use,the cause of yellow water was ana-lyzed and a pilot scale study of the yellow water control technology was carried out.On the one hand,the water quality characteristics and rules of the formation of yellow water were monitored,the corrosion pipe scale composition of cast iron pipe was analyzed,and the cause of the formation of yellow water was explored.On the other hand,the pilot pipe network system was built,and the effect of residual chlorine,alkalinity,and corrosion inhibitor on the iron release was studied by the pilot system.The results showed that:The formation of yellow water was periodic,it was the en-hancement of hydraulic erosion led to the release of iron from the corrosion scale,and the corrod-ibility of water could also affect iron release.The main components of the corrosion scale were Fe3O4 and α-FeOOH,but the morphological characteristics and chemical composition of different corrosion scale layers varied.It is suggested that the residual chlorine in the pipe network should be controlled at about 0.4 mg/L,raising or lowering residual chlorine concentration would promote the iron release.When dealing with the sudden yellow water problem,and considering the control efficiency and economy comprehensively,it is suggested to use 0.5 mg/L(as P)tripolyphosphate preferentially as the corrosion inhibitor to control the yellow water phenomenon of the pipe net-work.The extra cost for water treatment per ton is about 0.018 yuan.
Water supply networkIron releasePipe scaleYellow waterCorrosion inhibitor
万方数据
维普
