Formation potentials of bromate and brominated disinfection by-products in bromide-containing water by ozonation

Lin, Tao; Wu, Shouke; Chen, Wei

Formation potentials of bromate and brominated disinfection by-products in bromide-containing water by ozonation

2014

Lin, Tao | Wu, Shouke | Chen, Wei

The ozonation involved in drinking water treatment raises issues of water quality security when the raw water contains bromide (Br⁻). Br⁻ions may be converted to bromate (BrO₃⁻) during ozonation and some brominated disinfection by-products (Br-DBPs) in the following chlorination. In this study, the effects of ozone (O₃) dosage, contact time, pH, and Br⁻and ammonia (NH₃-N) concentrations on the formation of BrO₃⁻and Br-DBPs have been investigated. The results show that decreasing the initial Br⁻concentration is an effective means of controlling the formation of BrO₃⁻. When the concentration of Br⁻was lower than 100 μg/L, by keeping the ratio of O₃dosage to dissolved organic carbon (DOC) concentration at less than 1, BrO₃⁻production was effectively suppressed. The concentration of BrO₃⁻steadily increased with increasing O₃dosage at high Br⁻concentration (>900 μg/L). Additionally, a longer ozonation time increased the concentrations of BrO₃⁻and total organic bromine (TOBr), while it had less impact on the formation potentials of brominated trihalomethanes (Br-THMFP) and haloacetic acids (Br-HAAFP). Higher pH value and the presence of ammonia may lead to an increase in the formation potential of BrO₃⁻and Br-DBPs.

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