Comparison of UV/H2O2, UV/S2O82−, solar/Fe(II)/H2O2 and solar/Fe(II)/S2O82− at pilot plant scale for the elimination of micro-contaminants in natural water: An economic assessment

•Solar photo-Fenton and UV highly efficient in the removal of micro-contaminants.•Comparison between solar photo-Fenton and UV must consider an economic assessment.•Solar and UV with 50 mg/L of H2O2 and UV with 50 mg/L of peroxydisulfate showed similar costs.•Total costs increase if more than 99% degradation of micro-contaminants is required.

One of the most important factors affecting the application of advanced oxidation processes (AOPs) at full scale are the high operating costs, especially those associated with the cost of the reagents. Therefore, the optimization of operating parameters, such as a reduction in reagent consumption to achieve the partial or complete decontamination of waters, is crucial in AOP application. The present study is focused on the comparison of solar and UV photo-Fenton technologies (by using H2O2 or S2O82−), for the removal of five micro-contaminants (antipyrine, caffeine, carbamazepine, ciprofloxacin and sulfamethoxazole) from simulated freshwater at very low concentrations (100 ppb each one). In addition, economic assessment of the implementation of UV/H2O2, UV/S2O82−, solar/Fe(II)/H2O2 and solar/Fe(II)/S2O82− was also carried out. The total costs obtained were 0.42 €/m3 for solar/Fe(II)/H2O2 with 50 mg/L of initial H2O2, 0.72 €/m3 for solar/Fe(II)/S2O82− with 50 mg/L of initial S2O82−, 0.43 €/m3 for UV/H2O2 with 50 mg/L of initial H2O2, 0.49 €/m3 for UV/S2O82− with 50 mg/L of initial S2O82− and 0.61 €/m3 for UV/S2O82− with 25 mg/L of initial S2O82−. It was concluded that consumption of reagents and electricity costs coming from lamp operation in the UV process had a significant impact on the total operating cost of both technologies. Furthermore, it must be stressed that solar and UV processes promoted by H2O2 are more cost-effective than when employing S2O82−.