Electrocoagulation: Cod Removal Mechanism

Electrocoagulation (EC) is electrochemical water and wastewater treatment technology which in its simplest form uses an electrochemical cell where a dc voltage is applied to the electrodes, usually made of Iron or Aluminum, and the electrolyte is the water or wastewater. Current theory of EC has not been able to explain all the phenomena associated with the process, among others the differences in COD removal efficiency in wastewater. In this paper we discuss the facts associated with COD removal using EC and develop a mechanism that explains them. To do so first, a review of the technology is done. Second, the concept related to Oxygen Demand is discussed, next, the results from a pilot plant relative to COD removal efficiency using EC are shown. Last, two set of experiments and a mechanism for COD removal are presented. This mechanism fits data and observations, is congruent with the Iron Pourbaix diagram. Finally the factors affecting COD removal are mentioned.