ABATTEMENT DU CHROME PAR L ELECTROCOAGULATION DES EAUX USEES DE TANNERIE

Electrocoagulation is a way to reduce the level of emerging pollutants. Tannery is a socio-economic activity in which water and chromium are central elements. Tannery wastewater, the source of effluents containing emerging pollutants including very toxic chromium, is discharged into the treatment canals. The objective of the study is the reduction of chromium by electrocoagulation of tannery wastewater. The method consisted of separating impurities from a liter of wastewater sample using an electrocoagulator. The waste water is introduced into the electrolytic tank with two electrodes connected to the generator under electrical voltage. At each electrocoagulation the electrodes are cleaned with a 0.1 N sulfuric acid solution. After decantation and filtration (0.5u) the final concentration of chromium in the filtrates is determined. The results reveal that with a sample of initial concentration 16.59 mg/L in 45 minutes: at pH 7.15 the minimum reduction is 97.22%. At pH 8.59, the maximum reduction is 99.93%. In conclusion, electrocoagulation can reduce the chromium level in wastewater to 0.01 mg/L below the standard 2 mg/L. Reducing the rate of emerging pollutants in wastewater collected in Bamako is our perspective.