Enhancement of the Fenton and photo-Fenton processes by components found in wastewater from the industrial processing of natural products: The possibilities of cork boiling wastewater reuse

Some wastewaters from the industrial processing of natural products, such as cork boiling wastewater (CBW), have been known to contain high quantities of polyphenolic compounds that are capable of forming complexes with ferric and ferrous iron and even contributing to the reduction of ferric iron. The aim of this work is to evaluate how some of the major components found in CBW are able to influence the availability and regeneration of iron during the Fenton and photo-Fenton process, opening the way for its reuse. Presence of small quantities of CBW (1:50 related with wastewater to be treated) have been shown to increase availability of iron in natural water up to pH 5 and enhance the degradation of the insecticide Imidacloprid as well as a mixture of contaminants (phenol/methomyl/Imidacloprid) at near-neutral pH. Significant mineralization (>70%) of these compounds was also achieved at pH 5, with any added dissolved organic carbon (DOC) removed concurrently with the contaminants, with similar results to pH3 without CBW. The observed effects of the reused CBW are similar to the ones achieved by the addition of commercial iron-chelating agents such as Ethylenediamine-N,N′-disuccinic acid (EDDS) in photo-Fenton process.