Treatment of Irrigation Return-Flow Water Containing Pesticides Using Ozone

摘要

The treatment of irrigation return-flow water containing two pesticides, bromoxynil and trifluralin, was investigated using ozone (O_3) and O_3 combined with hydrogen peroxide (H_2O_2) in batch reactors. The results indicated that these pesticides could not be completely degraded during ozonation, achieving degradation levels lower than 50%. An enhancement of the level of degradation was observed using O_3/H_2O_2 process. A biphasic behaviour of O_3 was also observed. Acute toxicity analysis performed using Microtox? showed a decrease in the toxic effects of the samples on the luminescent bacteria during the first few minutes of treatment, followed by an increase of the toxic effects at the end of the reaction. The quantification of oxidation by- products generated during treatment was also addressed.