Characteristics of organic material in Huangpu River and treatability with the O3-BAC process
Résumé
This work investigated the characteristics of dissolved organic matter (DOM) in the source water from Huangpu River and treatability by the pre-ozonation, coagulation, filtration, post-ozonation and biologically activated carbon (BAC) process. The molecular weight distribution and DOC of each fraction obtained from membrane filters were analyzed. The results showed that the <3 kDa fraction contained mainly DOM from the raw water sample, suggesting that the water had been highly contaminated by anthropogenic activities. The raw water contained more hydrophilic fraction and less hydrophobic fraction, especially the non-acid hydrophilic fraction. Since there was a higher content of DOM in the <3 kDa and non-acid hydrophilic fractions, chlorination of the Huangpu River water produced a greater trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP), which indicated that the low molecular weight DOM and hydrophilic fractions were the major disinfection by-product precursors in the chlorine disinfection process. However, these DOM fractions cannot be effectively removed through conventional water treatment. The combined pre- and post-ozonation BAC process showed better removal efficiency of DOM and DBPFP compared to the conventional process. Furthermore, positive activity and dose-related effect was observed in the raw water extracts and no genetoxicity was observed for the sample from BAC in the Ames test. Therefore, the results of this study suggest that the advanced O3-BAC process is a better alternative for the treatment of drinking water from Huangpu River.