Electro-Oxidation (EO), also known as anodic oxidation, is a technique used for wastewater treatment, mainly for industrial effluents, and is a type of advanced oxidation process (AOP). The most general layout comprises two electrodes, operating as anode and cathode, connected to a power source.
Advanced oxidation processes (AOPs) have shown to be very useful technologies for application in different wastewater treatment areas. These processes use the very strong oxidizing power of hydroxyl radicals to oxidize organic compounds to carbon dioxide and water. These procedures usually involve the use of O3, H2O2, Fenton’s reagent and electrolysis to generate the hydroxyl radicals. However, some recent investigations have found that the use of a coupled processes using O3/electrooxidation increases the effectiveness of the process and also could reduce the operating costs associated to the application of AOPs. In this chapter, there is a description of our work in the treatment of wastewater using an ozonation-electrooxidation combined process. The main parameters to control for having a successful application of such method are discussed. Several examples for different kinds of polluted water are addressed
Traditional wastewater treatments involve the addition of chemicals or the use of microorganisms to treat polluted water. However, in both processes, there is always a residue known as sludge. The sludge management and final disposal could represent up to 50% of the total wastewater treatment plant cost. Therefore, novel ways to deal with this issue should be developed. In this way, the use of advanced oxidation processes (AOPs), in which the HO• radical production is favored, could represent an interesting option for treat wastewater with less or without sludge production.
The final goal of AOPS is the complete degradation of the pollutants present in wastewater, aiming its final mineralization, yielding as final products: carbon dioxide, water and inorganic compounds. These methodologies solve the problem of the final disposal of sludge; because when they are well developed, there is no production of sludge. Obviously, not always is possible the complete mineralization of contaminates. Nevertheless, most of the times, the final products of the destruction of contaminants are harmless compared to the original ones.