Treatment of wastewater from the dairy industry using electroflocculation and solid whey recovery

Abstract

The aim of this study was to investigate the efficiency of electroflocculation for the treatment of wastewater from the dairy industry and the recovery of solid whey. An electrochemical apparatus containing two aluminum or iron electrodes, a power source, an electroflocculation cell and magnetic stirring was employed. The following experimental conditions were monitored: electroflocculation time, initial pH of wastewater and applied potential intensity. Chemical oxygen demand, turbidity and final pH were the response variables. The chemical oxygen demand and turbidity decreased by employing aluminum or iron electrodes, applied potential intensity of 5 V, distance between two electrodes of 2 cm, 60 min electroflocculation time and initial wastewater pH of 5.0. The removal rates of organic matter based on the measure of chemical oxygen demand and turbidity when employing aluminum electrodes were 97.0 ± 0.02% and 99.6 ± 3.00 × 10−4%, respectively, with a final pH of 6.72. The removal rates of organic matter when employing iron electrodes were 97.4 ± 0.01% and 99.1 ± 1.00 × 10−4%, respectively, with a final pH of 7.38. In conclusion, electroflocculation is an excellent alternative for the dairy wastewater treatment in comparison to conventional treatment methods. The water used in food production and equipment washing is recovered with this method, resulting in a liquid that can be properly disposed. It is also possible to recover solid whey after electroflotation, which can then be used in the production of food supplements for humans and animals. Therefore, the dairy wastewater treatment process employing electroflocculation leads to sustainable food production.