AWWA ACE61681

The objective of this work was to examine the impact of raw water total organic carbon (TOC) concentration and alkalinity on the removal of the organic halide formation potential of the water by enhanced coagulation. Enhanced coagulation is considered to be the Best Available Technology (BAT) for the removal of disinfection byproduct (DBP) precursors. Enhanced coagulation is also mandated by the Stage 1 Disinfectants/Disinfection Byproducts (D/DBP) Rule, whereby specific TOC removal requirements are prescribed for the control of unidentified halogenated DBPs of potential public health concern. Twenty-seven waters were obtained from different utilities across the U.S.; three waters were obtained for each element of the 3x3 enhanced coagulation matrix. Jar tests were performed on each of the waters to determine the requisite alum dose for TOC removal in accordance with the enhanced coagulation Guidance Manual. Each of the waters was then treated with the requisite alum dose for enhanced coagulation, and the resulting settled waters, along with each of the raw waters, were chlorinated under uniform formation conditions. The chlorinated waters were analyzed for total organic halides (TOX). The formation of TOX in the raw waters and the effectiveness of coagulation for the removal of TOX formation potential were compared for each of the elements in the 3x3 enhanced coagulation matrix. Includes 23 references, tables, figures.