Decontamination of cork wastewaters by solar-photo-Fenton process using bleaching wastewater as H2O2 source

Abstract

This paper reports on a treatment strategy of cork wastewaters through the design of a solar-photo-Fenton process using cork bleaching wastewater as hydrogen peroxide (H2O2) source, as a pre-oxidation step, before a conventional biological oxidation process. This method proved to be efficient, achieving mineralization rates higher than 90% for different iron concentrations (2080 mg Fe L1 ). Higher iron concentrations resulted in the lower energy consumption and 60 mg Fe L1 was selected as the optimum dose for 91% mineralization and used for biodegradability studies. According to the ZahnWellens test, the optimum phototreatment energy to achieve a biodegradable effluent is 13.6 kJUV L1 (65% mineralization), which corresponds to H2O2 consumption of 76.1 mM (approximately 8.5 L of cork bleaching wastewater (at 7.7 g H2O2 L1 ) for 15 L of cork boiling wastewater).