Degradation of selected herbicides in a lowland surface water by ozone and ozone-hydrogen peroxide

The efficiency of ozone, and ozone in combination with hydrogen peroxide, for the degradation of five herbicides: Atrazine, Benazolin, Bentazone, Imazapyr and Triclopyr, under controlled laboratory conditions was investigated. Experiments were conducted at pH 7.5 in a bubble contactor column with a raw lowland surface water spiked with initial active ingredient concentrations of 2 mu g/L. Mean consumed ozone doses were approximately 1, 2 and 3 mg O-3/L. Hydrogen peroxide was added simultaneously to the application of ozone in a series of six mass ratios, between 0.0 and 1.0, with each of the consumed ozone doses. The results demonstrated a greater but varying removal of all herbicides achieved with increasing consumed ozone and applied hydrogen peroxide doses.