The influence of novel disinfection strategies in the removal of humic substances

Conventional drinking water production includes coagulation-flocculation, settling followed by sand filtration and chlorine disinfection. In order to avoid algae proliferation, pre and intermediate chlorination is usually effected. During these previous oxidation steps, water contains higher loads of organics; thus formation of chlorinated disinfection by products (DBP), such as trihalomethanes (THM), is favored. The nascent chlorine, ozone and chlorine dioxide combination generated in "CETOLAR" system presents greater oxidative power (synergy) than conventional chlorine. By the sum of oxidizers’ power, this “CETOLAR” system confers greater capacity of disinfection and it is possible, with a smaller dosage, to eradicate the pathogenic germs and avoid the presence of resistant germs. However, very little is known about its effect over natural organic matter (NOM). The present paper studies the effect of such a pioneering oxidation strategy on the content, nature and reactivity to form THMs of NOM.