[Influence factors of bromate formation in Yangtze River water during ozonation process]

A serial bench-scale experiments were conducted to study the effect of ammonia, pH, initial dissolved ozone and temperature on bromate formation during ozonation process in Yangtze river water, where bromide anion (Br(-)) was detected. Ammonia has little suppression effects on bromate production in Yangtze water at pH 7.35 and 0.6 mg/L ammonia background concentration, for it can't block the indirect-direct path. Within our experiment's conditions, at the initial dissolved ozone from 0.8 mg/L to 2.5 mg/L, it should be kept below 1.2 mg/L in order to avoid bromate standard violation. BrO3(-) formation is sensitive to pH variation. BrO3(-) production is 8 microg/L when pH decreases to 6.3. Lower temperature leads to both slower ozone decomposition and lower production of bromate. BrO3(-) production is 9.1 microg/L at 10 degrees C, 100 microg/L initial Br(-) and 1.6 mg/L initial dissolved ozone.