Study On Typical Disinfection By-products And Their Precursors In Yuqiao Reservoir

In recent years, the safety of drinking water has become the focus of public attention. Aiming at this issue, the paper studied trihalomethanes(THMs) and haloacetic acids(HAAs) and their precursors in water from Yuqiao Reservoir in Tianjin, China.First of all, the concentration of dissolved organic carbon(DOC),trihalomethanes formation potential(THMFP) and haloacetic acids formation potential(HAAFP) in water from Yuqiao Reservoir were detected regularly, whose aim was to acquire the current situation of organic matters, disinfection by-products(DBPs) and disinfection by-products formation potential(DBPFP). Then DOC in water was isolated into five different fractions using resin adsorption. These fractions were categorized as hydrophobic acid(HoA), hydrophobic neutral(HoN),hydrophobic base(HoB), weakly hydrophobic acids(WHoA) and hydrophilic matter(HiM). By comparing formation potential and specific formation potential of THMs and HAA5, the main precursors of these two kinds of DBPs were identified. Finally,the correlation degree between two indices, such as DOC and DBPFP, THMFP and HAAFP, specific ultraviolet absorbance(SUVA) and specific disinfection by-products formation potential(SDBPFP), were defined by correlation analysis, expecting to find substitute index of DBPFP and SDBPFP.The experimental results showed as follows:(1) The concentration of DOC,THMFP and HAAFP in water from Yuqiao Reservoir were 2.5~3.9mg/L, 64~468?g/L and 84.9~389.2?g/L respectively, which were relatively higher between June and September;(2) Compared with other surface water sources, DOC, THMFP and HAAFP in water from Yuqiao Reservoir were in a medium level;(3) Trichlormethane,dichloroacetic acid and trichloroacetic acid had higher concentration and formation potential among the nine kinds of DBPs.The results of DOC classification showed that HoA and HiM were the main fractions in the source water, secondly for WHoA and HoN, HoB concentration is the lowest of five fractions. In further analysis, HoA was found to be the main precursor of THMs and HAA5 because of the highest formation potential and specific formation potential of these two types of DBPs. Compared with WHoA, HiM had higherDBPFP and specific haloacetic acids formation potential(SHAAFP), excepting for specific trihalomethanes formation potential(STHMFP). In five fractions, HoB had the lowest formation potential and specific formation potential of THMs and HAA5.The results of correlation analysis indicated that DOC had moderate positive correlation with DBPFP(THMFP, HAAFP), and SUVA had moderate positive correlation with SDBPFP(STHMFP, SHAAFP) as well, while THMFP had a high positive correlation with HAAFP. DOC and SUVA can be selected as the reference index of DBPFP and SDBPFP respectively, but cannot be regarded as the substitute index.