Fluoride abatement from aluminium surface treatment effluents by electrocoagulation

In the present study, the treatability of an aluminium surface treatment effluent bearing high amount of fluoride (3360-6440 mg/L) and aluminium (2695-4690 mg/L) together with organic matter (340-370 mg COD/L) by electrocoagulation using aluminium electrodes was studied. The effect of varying operating parameters such as the applied current density (3.7-29.8 mA/cm ²), initial pH (2.55-3.86) and electrolyte (NaCl) concentration (500-3000 mg/L) on fluoride abatement as well as organic matter and aluminium removals was investigated. The results of the experimental study indicated that an increase in the applied current density significantly enhanced EC process performance whereas there was no significant effect of electrolyte (NaCl) concentration on pollutant removal efficiency. The electrocoagulation process proved to be effective and efficient for the treatment of aluminium surface treatment process effluents providing fluoride abatements up to 99% together with around 90% aluminium removals.