HYDROPHOBICITY CHARACTERISTICS OF NATURAL ORGANIC MATTER AND THE FORMATION OF THM (Pencirian Kehidrofobikan Sebatian Organik Semulajadi dan Pembentukan THM)

This study investigated the relationship between the characteristics of natural organic matter (NOM) and the formation of trihalomethanes (THMs). NOM from Semenyih river was isolated using resin adsorption method into six fractions based on hydrophobicity and acidity. Hydrophobic acid (40 %) and hydrophilic neutral (22 %) were the major component in the water sample. All the six classes of NOM were evaluated for their trihalomethane formation potential (THMFP) and related parameters. The result shows that the major fractions (hydrophobic acid and hydrophilic neutral) were not the reactive organic fractions in the formation of THMs. Hydrophobic base and hydrophilic base were found to be the most reactive fractions of concern with respect to the formation of THMs. Hydrophobic contents in NOM favoured the formation of THMs. In addition, increasing pH from 6 to 9 increased THM formation. The results from the present study indicated that the identification and specific removal of NOM fractions in raw water would minimize the formation of THMs during chlorination process.