Compared with traditional chlorination, sequeutial chlorination, i.e. short-term free chlorine plus chloramine disinfection can lower 35.8%～77.0% of trihalomethane formation and 36.6%～54.8% of haloacetic acids formation.
GC/MS test showed that total organic species number was reduced 59.7% and total spectrum aera was reduced 33% after treatment by“pretreatment+ozone+BAC+chlorination”, on the other hand, total organic species number was reduced 44% and total spectrum aera was reduced 13% after treatment by“pretreatment+air+BAC+chlorination”.
It is compared that the efficiency of control disinfection by-products and their precursors by sequeutial-chlorination disinfection and traditional free chlorination disinfection following different processes combination.
The data show that Ames test can only detect the mutagenicity of the chlorinated disinfection drinking water, while the comet assay of primary mouse hepatocytes can detect the mutagenicity of source water and chlorinated disinfection drinking water. The detection liminal value of the comet assay is much lower than that of Ames test.
DNA damage induced by organic extracts from drinking water and source water in city C can be found and comet length means from drinking water is longer than that from source water, suggesting that chlorinated disinfection can enhance DNA damage induced by organic extracts.