The relationship between disinfection by-products formation and characteristics of natural organic matter in raw water

Abstract

The influence of the characteristics of natural organic matter (NOM) on disinfection by-product formation was investigated for Maeri raw water, located in downstream of Nakdong river and Hoedong reservoir at Busan in Korea. The NOM was chlorinated and analyzed for trihalomethanes (THMs), 5 haloacetic acids (HAA-5) and total organic halide (TOX). Aromatic contents determined by specific UV absorbance at 254 nm (SUVA) correlated well with THMs, HAA-5 and TOX formation for the NOM in the Maeri raw water and Hoedong reservoir. Especially, THMFP/DOC showed better correlation with SUVA than HAAFP-5/DOC and TOXFP/DOC with SUVA. Chloroform formation showed good correlation with SUVA for Maeri raw water, but poor correlation with SUVA for the Hoedong raw water. In addition, TCAA formation potential showed good correlation with SUVA for both raw waters. In contrast, a lack of correlation was observed for DCAA formation for both raw waters. THM formation per unit DOC concentration was 70.2–81.1% and 18.9–29.8% for hydrophobic and hydrophilic organic matter in the Maeri raw water, respectively, in which the hydrophobic organic matter had much higher THM formation. In contrast, HAA-5 formation per unit DOC concentration varied seasonally for Maeri raw water. THM formation in the Maeri raw water had a good correlations with SUVA regardless of the ratio of hydrophobic and hydrophilic fraction, and THM formation per unit DOC concentration was higher for the order of humic acid>fulvic acid>hydrophilic organic matter. HAA-5 formation per unit DOC concentration for the hydrophilic organic matter was about 30 μg per mg DOC regardless of SUVA values, but HAA-5 formation per unit DOC concentration for the hydrophobic organic matter was proportionally increased with increasing SUVA values. However, the HAA-5 formation per mg DOC was the highest for the hydrophilic organic matter.