An electrocoagulation unit for the purification of soluble oil wastes of high COD

In spite of abundant literature on the topic, the efficiency of electrocoagulation for a specific effluent cannot be predicted in advance. Prior to designing an industrial wastewater treatment unit, preliminary treatment tests have to be done using different soluble oil wastes with a very high chemical oxygen demand (COD). The influence of various parameters can then be assessed. Coagulant dose, linked to the electrical charge passed and the nature of the waste, seem to be the controlling parameters of process efficiency. The results obtained at the laboratory-scale have been confirmed in a small pilot cell, and an industrial unit has been designed. A preliminary economic study shows that electrocoagulation may be competitive with current treatment technologies. From knowledge gained at bench-scale, we concluded that electrocoagulation appears to be a suitable process for treatment of soluble oily wastes with high COD.