Evolution of bromates and organobrominated compounds in two drinking watertreatment plants

A study of concentration of bromates and THM has been made during a year on two surface water treatment plants which supply drinking water to the city of Paris. The concentrations of bromates and THM are always under the E.U guidelines, but the results on the two plants whose treatments are differen t (one physico-chemical, the other biological), depend on different paramet ers. Temperature seems to have a greater influence on the formation of brom ate in the physico-chemical treatment. On the biological plant, slow sand f iltration removes BDOC leading to a potentially higher formation of bromate s. Concentrations of different THM are not significantly influenced by Br- concentrations.