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The present study is carried out to remove chromium and turbidity from tannery wastewater using the electrocoagulation process with aluminum electrodes. This experimental study is carried out using a batch system. The applied pilot comprises a reactor containing two parallel metal electrodes (Al). The latter are connected as monopolar, and a different potential is applied between them. Several working parameters, such as applied potential difference, electrolysis time, active electrode surface, interelectrode distance, and the pH of the medium have been studied to achieve higher removal efficiency. The treatment reached a maximum reduction of 99% for turbidity and 93% for chromium under the following conditions: 15 V applied potential difference, 45 cm2 electrode surface, 1 cm interelectrode distance, pH 6.1 raw water, and a contact time of 90 min. Given the treatment efficiency obtained in this study, electrocoagulation process has the potential to be used for the cost-effective removal of wastewater pollutants.

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The electrocoagulation (EC) process is an efficient and low-cost system for the purification of wastewater.The aim of this work was to investigate the efficiency of two types of aluminum (Al) electrodes (Al alloy and pure Al electrodes) for the treatment of synthetic semi-skimmed milk wastewater. Turbidity, chemical oxygen demand (COD), and concentration of Al species were monitored during the experiments. The effect of various parameters, such as current density and type and nature of the electrode were examined. The results showed that Al alloy electrodes exhibited a higher efficiency than pure Al electrodes. A quasi-total reduction of turbidity and a removal of approximately 58% of the COD were achieved within 24 min at pH 7 and a current density of 14.3 mA.cm −2 . It was also observed that the removal performance was not affected by the state of the electrode surfaces (polished) under the same operating conditions.

This present study focuses on the evaluation of the effectiveness and the feasibility of a combined treatment between the electrocoagulation (EC) and the adsorption on an activated carbon in grains (GAC) in a continuous mode. The peculiarity of this work is that the experiments are conducted with real wastewater from an industrial dairy. This combined treatment first required an optimization of the EC followed by an adsorption. For each of these techniques, different influential operating parameters such as the current density, the reaction time, the GAC dose, the initial turbidity of water … etc., have been studied. The Turbidity and the COD have been continuously analyzed, while the phosphorus, the BOD5, TSS, nitrogen and the grease have been punctually analyzed, and this happened before and after the water treatment. The EC adsorption coupling results have shown that the addition of an appropriate dose of GAC (2 gL−1) in a separate column, increases the effectiveness of treatment; more than 98 % of reduction for the COD, the BOD5, the turbidity and the greases. A mechanism explaining the phenomena which are involved in this combined treatment is proposed. On the basis of these results of efficiency, speed, low operational cost (~ 3 $m−3 of the treated water), and in comparison with the EC used alone, the EC coupling/the adsorption GAC, could be recommended as a treatment of separation for waters at a high load in organic pollutants.