Enhanced cork-boiling wastewater treatment by electro-assisted processes

摘要

In the cork processing industry, a large amount of highly polluted wastewater is generated during the cork-boiling step. In this work, we propose two novel approaches for the treatment of cork-boiling wastewater (CBW): (i) a sequential electro-coagulation coupled to Fenton oxidation process (EC + Fenton) and (ii) the electroFenton process (EF). Both technologies were tested at 80 degrees C with the stoichiometric dose of H2O2 required for complete mineralization of the organic matter. Both treatments resulted in a high TOC conversion, around 87%, with complete phenolic compounds removal. The resulting effluents were biodegradable (BOD5/COD > 0.65), containing non-toxic carboxylic acids as formic, acetic, oxalic and malonic acids. Regarding the economy of the process, the main cost is related to H2O2 consumption. In this sense, an initial physic-chemical pretreatment diminished the oxidant requirements and thus, the operational costs can be reduced by 40% in the EC + Fenton process.