USING FRACTIONATED NATURAL ORGANIC-MATTER TO QUANTITATE ORGANIC BY-PRODUCTS OF OZONATION

An improved procedure was used to isolate and fractionate natural orga nic matter (NOM) in water for subsequent ozonation and disinfection by -product (DBP) and color removal quantitation. Isolated NOM fractions from two different sources, accounting for approximately 50 to 60% of the dissolved organic material and 60 to 75% of the color, were charac terized and then ozonated under conditions approximating those encount ered during drinking water treatment. The natural waters also were ozo nated. Organic DBPs of either health concern or which may contribute t o biological instability of finished water were investigated, includin g aldehydes, oxoacids and low molecular weight carboxylic acids. pH an d ozone dosage were the parameters having the greatest effect on DBP f ormation. On the basis of UV absorbance measurements, the fulvic acid fractions studied taken together accurately represented the natural wa ter and may be the primary sources of precursor material for aldehydes and oxoacid DBPs. However, as yet unidentified NOM fractions contribu te significantly to carboxylic acid formation upon ozonation.