ABSTRACT
Natural organic matter was isolated and fractionated from surface water for subsequent ozonation and disinfection by-product (DBP) identification under conditions typical of drinking water treatment. Aquatic natural organic matter (NOM) was isolated from two source waters by adsorption on Amber-lite®* XAD-8 and XAD-4 macroreticular resins, and on Bio Rad®** AG MP-50 ion exchange resin. These fractions accounted for approximately 50 to 60% of the dissolved organic material and 60 to 75% of the color. They were characterized and then ozonated under a range of pH, alkalinity, and ozone dosages encountered during drinking water treatment. By-products of either health concern or which may contribute to biological instability of treated drinking water were investigated, including aldehydes, oxoacids, and low molecular weight carboxylic acids, and the results compared with those obtained by ozonating a standard material obtained from the International Humic Substances Society and by ozonating the natural waters. Comparison and correlation of by-product yields with reductions in ultraviolet absorbance are also reported. On the basis of ultraviolet absorbance measurements, the fulvic acid fractions studied accurately represented the natural water and may be the primary sources of precursor material for aldehydes and oxoacids formed during ozonation. However, the NOM fractions that were isolated in this research contributed less significantly to carboxylic acid formation.
