The Characteristics Of DBPS Formation And The Associated Removal Technique For The Source Water From Tai Lake

Tai Lake is one of the most important source waters in Yangtze River Delta. However, the water quality in Tai Lake is deteriorating due to the frequent human activities, and the organic pollution was severe because of the cynobacteria bloom occurred annually in recent decade years. It’s definitely needed pay more attention on studying disinfection by-products. In this thesis, we studied the formation of THMs, HAAs, HNMs, HANs, HKs upon disinfection (Cl2、NH2Cl2、O3+Cl2、O3+NH2Cl)of the organic matter from the raw water, sediment and soil. Also the removal effect for DBPs precursor among different technique (PAC, MIEX, AC) were also compared. Moreover, the extraction method of HNMs was also optimized. The results are as following:1) The dosage of Na2SO4exerted the most influence on the extraction efficiency of HNMs, and the second is CuSQ4. pH and shaking times doesn’t have much effect on the extraction efficiency in this study. The optimum conditions are as following:Na2SO4=6g; CuSO4=lg; pH=3.5-5.0, shaking times=120-180. The correlation coefficients of the calibration curves were more than0.9925(r>0.9925), the recovery (81-120%) and the method detection limit (MDL:0.017-0.217μg L-1) also showed good reliability and reproducibility of the method, which can be successfully applied in treated water.2) For Tai Lake water, high level of O3pretreatment (0.6-1.0mg/mgDOC) will increase the yields of HNMs (Cl2:4.7-5.6times; NH2C1:2.1-2.7times); HKs (Cl2:4.8-7.1 times; NH2Cl:2.5-2.9times); DHAAs (Cl2:1.5-2.4times; NH2C1:0.3-0.6times), thus, pretreatment of high O3dose is not recommended for Tai Lake water. What’s more, chloramination not only greatly reducd DBPs production, but also effectively control the generation of bromine containing DBPs as compared with chlorination.3) For the organic matter from Tai Lake sediment and soil, yields of DBPs from chlorination are also far more than that from chloramination. O3pretreatment can increase the yields of HNMs and HKs, but the effect is not so stable on THMs and HANs. Br-can increase the yields of HNMs, HANs, and increased the relative amount of bromine containing DBPs NO2-has little influence on the yields of DBPs.4) AC has best effect in removing the THMs and HNMs precursors for Tai Lake water as compare with PAC and MIEX, and the optimum flow velocity is16-32ml min-1. MIEX has a good effect on removing THMs and HNMs precursors when performed under low bed volume(BV), however if the bed volume becomes higher(>400BV), it doesn’t have obvious removal effect on HNMs. PAC also has a good effect to remove the THMs precursors (the best dosage is40mg L-1), but has little effect on removal of HNMs precursors.