Reducing the formation of disinfection by-products by pre-ozonation

The objective of this study is to apply the pre-ozonation process to reduce the formation of disinfection by-products (DBPs). The raw water sample, collected from the Te-Chi Reservoir in central Taiwan, has been polluted by fertilizer. Three types of resins were used to isolate the natural organic matter into seven types of organic fractions. The pre-ozonation was used to oxidize each organic fraction to study the reduction of DBPs of each fraction. Experimental results indicated that the pre-ozonation could reduce the concentration of dissolved organic carbon resulting in the reduction of DBP formation. With the pre-ozonation, 9-54% of DOC and more than 40% of DBPs were reduced. With the analysis of UV adsorption and Fourier transform infrared spectrometer (FTIR), the reduction of A254 and unsaturated functional groups such as aromatic ring and C=C bond containing in the water sample is the major reaction mechanism.