Disinfection by-product formation of natural organic matter surrogates and treatment by coagulation, MIEX ® and nanofiltration

Abstract

Potentially the most effective means of controlling disinfection by-products (DBPs) is to remove precursors before disinfection. To understand relationships between physical properties, treatability and DBP formation, nine natural organic matter (NOM) surrogates were studied. Their DBP formation and removal by coagulation, MIEX ® anion exchange resin and two nanofiltration membranes was measured. Whereas treatability of NOM surrogates was explained in terms of their physicochemical properties, the same was not true of DBP formation. Hence it was not possible to selectively remove compounds which generate high amounts of DBPs. Instead, precursor removal strategies based upon empirical DBP formation potential testing are more apt. Under conditions simulating full-scale performance, MIEX ® did not offer improved performance over coagulation. A hydrophobic nanofiltration membrane proved successful for removing neutral, hydrophilic surrogates, and hence is also suitable for DBP precursors of this character.