The application of electrochemical technology to the wastewater treatment

With the ever increasing standard of drinking water supply and the stringent environmental regulations regarding the wastewater discharge, electrochemical technologies have regained their importance worldwide during the past two decades. There are companies supplying facilities for metal recoveries, for treating drinking water or process water, treating various wastewaters resulting from tannery, electroplating, diary, textile processing, oil and oil in water emulsion, and so on. Nowadays, electrochemical technologies have reached such a state that they are not only comparable with other technologies in terms of cost but also are more efficient and more compact. For some situations, electrochemical technologies may be the indispensable step in treating wastewaters containing refractory pollutants. Electrochemical processes present interesting and ecological advantages for waste treatment: (i) saving of energy, since they function at ambient temperature, (ii) better performance, because the cell geometry can be designed to maximize product yield, and (iii) ease of control, since the kinetics of the processes are determined by the working potential and/or current density that can be readily adjusted as necessary. In this paper, the established technologies such as electrochemical reactors for metal recovery, electroflotation (EF), and electro-oxidation (EO) will be examined.