Bromate formation during ozonation of groundwater in coastal areas in Greece

This project studied bromate ion formation during ozonation of groundwater containing elevated bromide ion levels. Groundwater samples from aquifers in coastal areas were ozonated in a semi-batch reactor under typical ozonation conditions sufficient to inactivate microorganisms. Ozone dose and contact time played a significant role in bromate ion production. Bromate formation increased as the contact time increased under the same ozone dose. In addition, increasing the ozone dose while keeping a constant contact time resulted in increasing bromate formation. Further parameters that influenced the formation of bromate ions were the initial concentration of bromide ion and the product CT (ozone dose times contact time), which has been suggested as a control variable for effective ozonation. Empirical bromate formation models were developed in order to simulate the effect of water quality characteristics and treatment processes on bromate formation. The empirical models were capable of estimating the concentration of bromate ions in ozonated groundwater samples, which contain low concentrations of ammonia and dissolved organic carbon.