A ferrous oxalate mediated photo-Fenton system: Toward an increased biodegradability of indigo dyed wastewaters

► Indigo wastewaters are successfully treated with a solar assisted oxidation reaction. ► Using ferrous oxalate complexes, the efficiency of the treatment increases. ► Increasing peroxide concentrations did not improve the treatment substantially. ► The best removals of TOC and COD were reached with the smallest peroxide dose. ► A final complete biodegradability was obtained for these wastewaters.