The presence and the removal of atrazine, deethylatrazine, deisopropylatrazine and deethylhidroxiatrazine in a pilot plant consisted of ozonation and slow sand filtration

When preceded by ozonation, dose of 1.6 mg.L-1, the concentration of atrazine was less than 2 µg.L-1 and met the maximum value allowed by the Portaria 2,914/2011; however, the concentration of byproducts was over 18 µg.L-1. For ozone dose of 2.8 mg.L-1, atrazine value in the filtered effluent was less than 0.1 µg.L-1, but the sum of chlorinated byproducts was equal to 3.7 µg.L-1. The assessment of the removal of atrazine in processes using ozonation should always be associated with the monitoring of chlorinated byproducts, especially deethylatrazine considering that: there is formation of those in higher concentration of atrazine producing water supply with a high health risk and those not included in Portaria MS 2,914/2011.