A mixture of five commercial pesticides (Vydate((R)), Metomur((R)), Couraze((R)), Ditimur-40((R)) and Scala((R))) commonly used in intensive agriculture has been selected as an example of highly toxic, non-biodegradable wastewater to be treated by solar Photo-Fenton. The effect of the total concentration of organics as dissolved organic carbon (100-500 mg/L), operating temperature (25-50 degrees C), dissolved iron concentration and their relationship to different process efficiency parameters (mineralization rate, hydrogen peroxide consumption and treatment time) were evaluated Experiments were carried out under sunlight in a pilot plant It consists of four compound parabolic collectors (CPCs) and a total volume of 75 L From the results of the study it can be concluded that solar plants should be designed for operating at temperatures below 45 degrees C to avoid significant loss of iron H2O2 should be carefully dosed during the photo-Fenton treatment to avoid its continued excess and inefficient use (C) 2010 Elsevier BV All rights reserved