Chemical composition and direct electrochemical oxidation of table olive processing wastewater using high oxidation power anodes

Abstract Table olive processing wastewater (TOW) is a notoriously polluting due to its high organic and phenol content. To reduce them, an electrochemical process has been studied for the treatment of this effluent. Experiments were performed with a cell equipped with lead dioxide (PbO 2 ) or boron-doped diamond (BDD) as anode and platinum as cathode, where Table Olive Wastewater (TOW) were destroyed by hydroxyl radicals formed at the anode surface from water oxidation. The comparative study of both systems shows the performance of the BDD anode compared to PbO 2 , explained by the large amounts of hydroxyl radicals generated effective at BDD anode and its synthesis characteristics. Using LC/MS analysis, it was possible to determine hydroxytyrosol, as major phenolic compounds, in table olive processing wastewater and its concentration reach 890 mg L −1 . A possible reaction mechanism oxidation for hydroxytyrosol was proposed. The kinetics decays for hydroxytyrosol degradation on PbO 2 anode follows a pseudo-first order reaction with a rate constant 0.9 h −1 for j app value 20 mA cm −2 .