Electrocoagulation is the process of destabilizing suspended, emulsified or dissolved contaminants in an aqueous medium by introducing an electrical current into the medium. The electrical current provides the electromotive force to drive the chemical reactions. When reactions are driven or forced, the elements or compounds will approach the most stable state. Generally, this state of stability produces a solid that is either less colloidal and less emulsified (or soluble) than the compound at equilibrium values. As this occurs, the contaminants form hydrophobic entities that precipitate and can easily be removed by a number of secondary separation techniques. Stated another way:
“[Electrocoagulation] utilizes direct current to cause sacrificial electrode ions. to remove undesirable contaminants either by chemical reaction and precipitation or by causing colloidal materials to coalesce and then be removed by electrolytic flotation. The electrochemical system has proven to be able to cope with a variety of wastewaters. These waters are paper pulp mill waste, metal plating, tanneries, canning factories, steel mill effluent, slaughter houses, chromate, lead and mercury laden effluents, as well as domestic sewage. These wastewaters will be reduced to clear, clean, odorless and reusable water. In most cases, more especially domestic sewage, the treated water effluent will be better than the raw water from which it had originated.”4
In the Electrocoagulation process, the electrical current is introduced into water via parallel plates constructed of various metals that are selected to optimize the removal process. The two most common plate materials are iron and aluminum. In accordance with Faraday’s Law, metal ions will be split off or sacrificed into the liquid medium. ‘these metal ions tend to form metal oxides that electromechanically attract to the contaminants that have been destabilized.
(4) Eckenfelder, W.W. and Cecil, L.K.. “Applications of New Concepts of Physical-Chemical Wastewater Treatment.” Vanderbilt University; Nashville, TN: Pergamon Press, Inc.