Full Description

Natural organic matter (NOM) from five water sources was fractionated using XADresins and ultrafiltration membranes into different hydrophobicity and molecular weight(MW) groups. The disinfection byproduct (DBP) formation from each fraction duringchlorination and chloramination was studied. In tests using chlorination, hydrophobic andhigh MW (e.g. 3kDa) precursors produced more trihalomethanes (THMs), trihaloaceticTHAA) acids and unknown total organic halogen (UTOX) than correspondingtransphilic, hydrophilic and low MW (e.g. 3kDa) precursors. However, the formation ofTHMs and THAA was similar among different fractions for a water with low humiccontent. Hydrophilic and MW0.5k fractions gave the highest dihaloacetic acid yields.No significant difference was found for the dihaloacetic acid and UTOX formationamong different fractions during chloramination. It appears that chloramination DBPprecursors are more evenly distributed among NOM fractions. High pH favors theformation of THMs and HAAs over UTOX. Increasing pH also led to lower TOXformation for hydrophobic and high MW fractions, but had little impact on TOX yieldsfrom hydrophilic and low MW fraction. Bromine and iodine were found to be morereactive with hydrophilic and low MW fractions as measured by THM and HAAformation than their corresponding hydrophobic and high MW fractions. However,hydrophobic and high MW fractions produced more UTOX when reacting with bromineand iodine. Includes 39 references, tables, figures.

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Edition: Vol. - No. Published: 06/17/2005 Number of Pages: 20File Size: 1 file , 1.8 MB