The Studies Of Detecting Haloacetic Acids And Exploring Their Rules Of Changing In The City's Water Supply System

Recently water supply industry pays more and more attentions to disinfectionby products in the water. Because our city is using chlorine to disinfect drinking water,during this procedure many disinfection by products, such as THMs and HAAs, areproduced. Based on other studies, we know that the cancer risk of HAAs is 50 to 100times higher than the cancer risk of THMs. Both《Water Quality Standards for UrbanWater Supply》,which was published by Ministry of Construction in 2005, and《Sanitary standard for drinking water》,which was published by Ministry of Healthand National Standardization Administration in 2006, limited the amount of HAAs inthe drinking water seriously.This study includes: Establish the detection method to HAAs. Decide where andhow to collect samples in the water supply system of Tianjin. Measure theconcentration of HAAs, as well as the concentration of THMs and other relative itemsin the samples, which are collected in resouces, water treatment factories andwater delivering systems. Analyze the change and tendency of HAAs in the watersupply system of Tianjin, and several factors'influences on creating and keeping ofHAAs. Give effective suggestions to control HAAs in the drinking water according tothe conclusions above.After one year study, we make several conclusions below: There are no HAAs inthe upstream reservoirs. There are no HAAs in the ground water in Tianjin, either. Theconcentration of HAAs in the water supply system is below the national standards.From the beginning of water treatment to the resident's taps, the concentration ofHAAs show an approximate tendency: increase sharply, maintain the level, anddecrease quickly. Many things, such as the organic substances in the water, theposition to add chlorine, the amount of chlorine, the temperature of the water and thestatus of the water conduits, can influence the HAAs in the water. When the amountof organic substances or chlorine is changed, the level of HAAs will change in thesame direction. The earlier chlorine is added into the water, the more HAAs will beproduced. Temperature and HAAs show an obvious correlation. But there is norelation between the water conduit's length and HAAs. The HAAs'concentration isdecided by both length and the layout of the conduit at the same time.