Ultrasound-assisted electrocoagulation process applied to the treatment and reuse of swine slaughterhouse wastewater

The use of combined approaches, such as physicochemical processes, in the treatment of wastewater is currently being widely applied, especially for complex matrixes like swine slaughterhouse wastewater. The objective of this study was to investigate the performance of swine slaughterhouse wastewater treatment, applying electrocoagulation-flotation (ECF) and ultrasound-assisted electrocoagulation-flotation (ECF/US) processes using Al and Al/Fe electrodes. The effect of current, pH and treatment time was evaluated. The best experimental conditions for the process were current of 5 A, potential of 6 V, distance between electrodes of 10 mm and time of 60 min, using Al electrode. In general, the parameters of the swine effluent treated by ECF showed an average efficiency above 90 % in the removal of contaminants when the Al electrode was used for a time of 60 min. In this case, the best results were: removal of color 97 %, turbidity 97.4 %, BOD 93 % and oil & grease 90 %. When the Al/Fe electrodes were used, the best results were: removal of color 95.5 %, turbidity 96.2 %, nitrogen 93.4 %, and BOD 90.7 %. Similar results were obtained with the ECF/US process, but this required a treatment time of only of 25 min. The treated wastewater, after filtration through an activated carbon filter, satisfies criteria for use as reuse water, demonstrating that ECF and ECF/US are promising techniques for wastewater treatment.