Bromide consumption during chlorination SDS of the optimally treated water was determined by measuring the residual bromide after 72 hours chlorine contact; results are shown in Table 2. The results for the WA water source showed that not all bromide was consumed for any of the three ratios, with measurable Br residuals detectable after 72 hours chlorine contact; amount consumed 85%, 89% and 80% for Br:DOC ratios 1:13, 1:8 and 1:4, respectively. Similarly bromide residuals were detected for the ratios, 1:8 and 1:15, for the SA water source with 74% and 76% consumed, respectively, while bromide was undetectable at a Br:DOC ratio of 1:52. As HOBr is the faster reacting oxidant, complete consumption of the bromide was expected. However Wang & Huang (2006) have shown that incomplete oxidation of bromide to HOBr can occur, so all of the bromide may not have been available for reaction with DOC in our samples. Assuming that bromide, HOCl/OCl⁻ and DOC are in equilibrium, coupled with the fact that similar percentages of bromide were consumed in all Br:DOC samples, suggests that HOCl/OCl⁻ and DOC were not limiting the reaction. Rather, the amount of bromide incorporated appeared to be dependent on the initial bromide concentration not the Br:DOC ratio, although this could not be conclusively proved due to the limited data and difficulty of modifying the Br:DOC ratio without changing the bromide concentration.