ALTERNATIVE OPTIONS FOR ATRAZINE - INCIDENCE ON WATER-TREATMENT DEVICE

In recent years, triazine residues are often evidenced in surface waters as well as in underground waters. The European standards for the maximal level of each pesticide in water for human consumption is 0.1 mug.1-1 which raises problems for triazines such as atrazine or simazine. New molecules have been designed to replace atrazine and the aim of our study is to evaluate on a pilot plant the outcome of two triazines wich could be used instead of atrazine and simazine ; these two triazines are cyanazine and terbuthylazine. These triazines are not removed by coagulation, floculation, decantation. Cyanazine is well eliminated by slow sand filtration. Ozonation has no effect on cyanazine but eliminates 40 % of terbuthylazine. Mechanism of elimination of terbuthylazine on slow sand filters seems to be reversible adsorption which can lead to re-release of this pesticide in case of variation of concentration in the influent water.