Advanced Water Treatment for Removal of Chemicals Difficult to Treat by Water Purification

Abstract

We investigated the efficiency of an advanced water treatment to remove formaldehyde (FA) and chloroform (CF) precursors. The formation potential of haloacetic acid (HAA) from CF precursors was also evaluated. The results of a jar test showed that FA and CF precursors, except for acetonedicarboxylic acid (ADC) , were not removed by raising the dosage of a coagulant. On the other hand, the results of the test at the experimental plant showed that FA and CF precursors were removed, and the formation potential of FA, CF and HAA, were reduced by ozonation and granular activated-carbon treatment. We found that ADC and 1,3,5-trihydroxybenzene were not only the precursors of CF, but also the precursors of dichloroacetic acid and/or trichloroacetic acid.