Investigation of the efficiency of a designed electrocoagulation reactor: Application for dairy effluent treatment

Abstract Here we present a new electrocoagulation reactor operating with 20 aluminum electrodes in bipolar configuration mode. The disposition and the orientation of the electrodes (tilted to form an angle of 7° with respect to the horizontal direction) provide simple handling and efficient condition for electroflotation. The reactor has excellent electrical stability over time due to the good circulation that prevents the accumulation of flocs on the electrodes. Throughout the treatment, there is thus a good stability of the voltage measured at fixed current density. This reactor was used successfully for the treatment of a dairy effluent. During processing, the influence of key experimental parameters (the current density, the charge loading and the initial pH of the effluent) was studied on the reactor performances for the removal chemical oxygen demand (COD), phosphate ions (PO 4 3− ), suspended solids (SS) and turbidity. General trend observed in other electrocoagulation reactors operating with aluminum electrodes were obtained. Under optimal experimental conditions (current density of 0.65 Am −2 , charge loading of 0.59 Fm −3 and initial pH of 6), the removal efficiency was 80% for COD, 98% for phosphate and 100% for SS and turbidity. The energy consumption at these optimal conditions was very low (0.163 kWhm −3 ). Considering the relative easy handling of the reactor, the price of the aluminum electrodes and the energy consumption, we determined a cost associated to the dairy effluent used is 0.026 $ m −3 .