Traitement des eaux résiduaires d’industrie de textile par électrocoagulation en réacteur continu

Abstract

Electrocoagulation (EC) is an effective treatment for highly polluted industrial wastewater. It has been used successfully for the treatment of various industrial effluents including effluents issues from food industries, tanneries wastewater, water containing metals or heavy metals, wastewater contained soluble oil issued from mechanical workshop, polymerization manufactures, and textiles industries. The main objective of this study was to investigate the effects of the operating parameters, such as initial pH, initial concentration (C0), residence time (τ), current density (j), inlet flow rate (Q), direct/ alternating current (DC/AC) and electrode connection systems on the removal of a red nylosan dye (Acid Red 336) by EC process using aluminum electrode in a continuous electrochemical reactor. The optimized parameters will be applied to the treatment of a real textile effluent. Our results suggest an opportunity for the application of continuous EC process to remove color and turbidity from wastewater. For example, A rate of abatement between 87 % and 96 % for color and turbidity was observed for the direct current, when the initial concentration of the dye C0 was ranged from 100 mg/L to 1000 mg/L, current density j = 300 A/m², conductivity κ = 2.5 mS/cm, inlet flow rate Q = 15 L/h and 26 L/h, treatment time t = 30 min and initial pH ranged from 3.46 to 9. The specific electrical energy consumption was 9.5 kWh per kilogramme of removed dye for direct current and monopolar connection. The recirculation of the wastewater increased considerably the elimination of the color and the turbidity for the two modes of connection (MP and BP), but for (MP-P) connection, the effect was not significant. For the influence of electrodes connection modes, the results showed that bipolar connection is slightly more effective compared to monopolar connection (MP) in terms of abatement of the color and turbidity. But in terms of consumption of energy, the bipolar mode (BP) consumes more energy than the monopolar mode (20 kWh per kilogramme of removed dye)