Conception et élaboration d’un réacteur d’électrocoagulation : Application au traitement des eaux de rejet industriel

Abstract

This novel approach has been applied to two reactors, of type A (5.7 L) and type B (25.8 L) that dispose each an active surface electrode of about 0.4212 m² and 1.23 m² respectively. The chosen electrical connection mode is bipolar: only the end plates are connected to the DC generator while the intermediate plates then acquire a bipolarity. The effluent circulates in a sinusoidal manner in the two reactors with respect to the arrangement of the electrodes. The effluent inlet into the reactor is positioned in the left parts and outlet on the right-side for the A and downwards parts from outlet upwards for the B. The arrangement of the electrodes has considerably reduced the voltage across the electrodes. The electrochemical behavior of the process is characterized both by the generation of coagulant and bulb. We applied the EC process for the treatment of constituted milk effluents, domestic sewage from the Camp-Sic district of Mendong and Etoundi wastewater from the city of Yaounde.. The current density and the charge density, which are the main parameters of the electrolysis for the electrocoagulation process were followed. The following pollution parameters were studied: the turbidity, suspended solids (MES), chemical oxygen demand (COD), phosphate (PO43-) and Biochemical oxygen demand for 5 days (BOD5). The FTIR analysis of the sludge produced after treatment show that there was not so much difference between these spectra. Experiments on laboratory-prepared specimens yielded conclusive results by removing 99% of TSS; 79% COD and 90% PO43- with the two designed reactors, while turbidity was completely eliminated. The optimization of the parameters was applied with interesting results to the domestic wastewater from the Mendong Camp-SIC and the Etoudi abattoir wastewater. For Mendong domestic wastewater, we were able to entirely eliminate TSS, 92.05% Turbidity and 93.52% COD, and for slaughterhouse wastewater, we achieved 98.96% for TSS, 97.64% for turbidity and 94.44% for COD using the Type B reactor. Moreover, these results suggest that the electrocoagulation process proves very effective for the treatment of different types of effluents. This consistent with the arguments developed in the literature regarding its effectiveness and low-cost approach. The results indicate that the concentration of pollutants decreases over time as the concentration of aluminium ions increases. The bubbles bring to the surface the flocs formed during the electrolysis. The treatment of both artificial effluent and real effluents elucidate that this process generates a small amount of sludge and the device is easy to remove and clean.