[Optimal process combination for control of disinfection by-products and precursors].

It is compared that the efficiency of control disinfection by-products and their precursors by sequential-chlorination disinfection and traditional free chlorination disinfection following different processes combination. 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. Moreover, the poorer the influent quality is, the more advantages sequential chlorination disinfection have over free chlorination disinfection. The formation of trihalomethane and haloacetic acids by sequential chlorination following the simplest traditional process is even less than their formation by free chlorination following the most complex process, pre-ozonization plus traditional one and ozonization-active carbon process. The results show that ozonization-active carbon process and pre-ozonization have better efficiency on control of disinfection by-products and their precursors. We recommend that water plants apply the sequential chlorination disinfection and ozonization-active carbon process.