Food Industrial Effluent Treatment with Oxygen and Ozone Using Activated Carbon for Catalytic Oxidation

Abstract

ABSTRACT A catalytic oxidation treatment to remove coloration and chemical oxygen demand (COD) in an effluent from a food industry was carried out using oxygen and ozone as oxidizing agents and activated carbon as a catalytic. Different experiments of oxidation were conducted using 25, 50 and 100 mL of activated carbon bed to treat 100 mL of sample and constant flow of oxygen 7.2 g/min and ozone 0.034 mg/min, maintaining initial pH of industrial effluent. Almost a complete coloration removal and COD reduction of the sample was achieved for catalytic processes; however, time of treatment and agent oxidant doses were different in each case. According to volume of activated carbon beds, ozone doses for discoloration and COD removal were 8.5, 2 and 1.7 mg/L, whereas the oxygen doses were 2860, 770 and 500 g/L, respectively. Consequently, to eliminate the color in the industrial effluent, the dose of oxygen was higher than that of ozone. In addition, the oxidation agents promoted the regeneration of activated carbon, showing that its activity is declined after 60 cycles of effluent treatment with ozone, whereas with oxygen treatment, the total depletion was observed in 18 cycles. In turn, single adsorption showed activated carbon depletion in 5 cycles of effluent treatment.