Electrochemical treatment of wastewater from almond industry using DSA-type anodes: direct connection to a PV generator

Abstract

Food industries such as almond industry generate large volumes of wastewater in their processes and common techniques are not always efficient for treating this kind of effluents. In this work, the feasibility of a treatment for pollutants removal of a real industrial wastewater by electrochemical oxidation s studied at laboratory scale and then scaled-up to pre-industrial scale. The first stage of the work was performed at laboratory scale, using a 63 cm2 cell, where different anodes (Ti/Pt, and DSA anodes (Ti/RuO2 and Ti/IrO2)) and the optimal experimental conditions (pH, current density, temperature and [Cl-]) were studied and established. By using a DSA-Cl2 anode (Ti/RuO2), pH 9, j = 50 mA cm-2, [Cl-] = 2000 mg L-1 and room temperature, chemical oxygen demand (COD) was removed up to 75% and results show that electrooxidation can remove organic pollutants. In the second stage the scaling-up of the process from laboratory to pre-industrial scale was performed, by using a 3300cm2 cell. The electrochemical reactor was finally powered by a photovoltaic generator directly connected, in order to operate by using a renewable energy and a COD elimination of 80% was achieved.