Study On Removal Of Disinfection By-product Precursors By Anvanced Treatment Process In Water Of Yellow River Reservoir

The paper discussed the removal of disinfection by-products (DBPs) precursors by anvanced treatment process in Yellow River Reservoir water. On this basis, lab trials went on to change the operating parameters to study the removal of DBPs precursors furtherly by enhanced coagulation, activated carbon adsorption and advanced oxidation, which would offer data support for reducing DBPs in dring water.Through the one-year analysis for raw water, it was found that trihalomethane formation potential (THMFP) is more than haloacetic acids formation potential(HAAFP), and meanwhile, the proportion of chlorine-byproducts formation potential is higher than the brome-byproducts. The main types of THMs were chloroform, bromodichloromethane and dibronochloromethan and the HAAs included trichloroacetic acid and dichloroacetic acid mainly. However, the formation potential of bromoform, bromoacetic acid and monochloroacetic acid were less than5μg/L and the monochloroacetic acid was below the detection limit. In addition,the THMFP was highest in summer, contrary, HAAFP in summer was lower than other seasons. It showed a good correlation with UV254of the THMFP and HAAFP, and the correlation coefficient were0.9325and0.949respectively, which could be used as an alternative parameter of DBPs precursors.The results demonstrated that, the DBPs precursors were removed effectively in the finished water from advanced treatment process, of which the proportion of bromo-products increased while the chlorinated by-products reduced. From February to November, the total removal of THMs precursors showed a descended trend, and the highest removal rate was49%in June and July, while the lowest removal rate was15.7%in November. The THMs remval rates of high-density sedimentation tanks, ozone contact tank, biological activated carbon pools and sand filter were4.8%-9.8%、15%-20.5%、4.1%-16.9%and O-8.5%respectively. The removal rate of HAAFP changed with seasons, which showed a trend of increased first but fell then, the maximum removal rate reached72.2%in June, The removal rates of HAAFP for each process unit were9.5%-23.2%、19.4%-24.8%、13%-20.7%and5.2%-11.8%, obviously, it could be seen that advanced treatment process for the removal of THMs precursors were better than HAAs, and the descending effect of each process unit for the removal of DBPs precursors were:ozone contact tank> biological activated carbon pool> high sedimentation tank sand filter, and combined process effluent quality meets drinking water health standards "(GB5749-2006).In term of DBPs removal, advanced treatment process were better than conventional treatment process, the removal rate of THMFP in conventional treatment process were0-40%, while the HAAFP were30%-60%, it could be seen that the removal of HAAs precursors were superior to THMs in conventional treatment process.Enhanced coagulation could remove36.5%THMs precursors, and the effect of adsorption was better than biodegradation on the BAC process segment in removing the precursors THMs. However, regardless of enhanced coagulation or adsorption, the reduction of the THMFP attributed to trichloromethane. During advanced oxidation processes, ozone oxidation could remove approximately21.9%of THMFP, when [O3]/[H2O2](M/M) was1:3, THMs precursors could be removed well by the combined process of O3/H2O2and the removal efficiency could achieved to32%; In removal efficiency respect, combined process of O3/H2O2were best while H2O2/UV were worst.