Electrochemical treatment applied to food-processing industrial wastewater

The removal of organic pollutants from food-industry wastewater by an aluminum electrocoagulation process was evaluated using a pilot batch reactor coupled to a rotating electrode. Under optimal conditions of pH 4, 18.2 A m(-2) current density, and 150 rpm electrode rotational velocity, the electrochemical method yields a very effective reduction of all organic pollutants. Treatment reduced chemical oxygen demand (COD) by 88%, biochemical oxygen demand (BOD5) by 52%, total solids by 82%, and total coliforms by 93%. The effect on the species formed of reducing the pH of the aqueous solution with sulfuric acid was determined. The wastewater quality was monitored using UV-vis spectrometry and cyclic voltammetry in order to characterize initial and final pollutant levels. Finally, the morphology and elemental composition of the resulting sludge was characterized using scanning electron microscopy (SEM) and energy-dispersion spectroscopy (EDS).