The combined effect of irradiance and iron concentration on photo-Fenton treatment cost Free

Industrial wastewaters, which are often toxic and non-biodegradable so that conventional biological treatments cannot be applied, becomes one of the most important factors affecting the water scarcity problem. In this context, advanced oxidation processes (AOPs) have attracted the attention of researchers as these can oxidize almost any type of pollutant due to the generation of highly reactive transitory species (mainly hydroxyl radical). This study evaluates the combined effect of the initial photo-catalyst concentration and irradiance level on photo-Fenton efficiency. For the lowest iron concentration, 8 mg/L, iron limited process performance. The 20 mg/L experimental series showed that the process was run under photo-limitation while, for the highest iron concentration, hydrogen peroxide consumption was increased unnecessarily with no improvement of the treatment times and QUV values. Under the conditions studied, the economical assessment showed that total cost was between 0.76 and 1.39 €/m³, obtaining the best result for 20 mg/L of iron and 46 W/m². Under low UV irradiance, the use of low iron concentrations is recommended from an economical point of view.