Tebuthiuron and ametryn formulations degraded in a flow plant with BDD/air-diffusion cell. Growing oxidation power over single herbicide formulations: AO-H2O2 < EF < SPEF. Two-stage kinetics in EF and SPEF due to the formation of Fe(II) and Fe(III) complexes. Similar profiles with lower oxidation ability for mixed herbicide formulations in SPEF. Identification of 4 heteroaromatic products in mixtures and release of sulfate and nitrate ions.