Bio-electro-Fenton: A New Combined Process – Principles and Applications

Abstract

Biological treatments show insufficient removal efficiency in the case of recalcitrant organic compounds. Therefore, the necessity of upgrading wastewater treatment plants (WWTPs) with advanced treatment steps is unequivocal. Advanced oxidation processes (AOPs) are the most effective technologies for the removal of a large range of organic pollutants from water due to the generation of strong oxidizing species like hydroxyl radicals (•OH). However, AOPs often involve high energy and/or reagent consumption and are considered as less cost-effective than biological processes. Hence, the combination of AOPs and biological treatments has been implemented aiming at maximizing efficient removal of recalcitrant organic pollutants while minimizing treatment costs. Among AOPs, electrochemical advanced oxidation processes (EAOPs) have been widely explored during coupled processes, since they possess remarkable advantages, such as high efficiencies, operability at mild conditions, economic feasibility, ease of automation, as well as eco-friendly character. The electro-Fenton process (EF) stands out as one of the most applied EAOPs and the present chapter is devoted to the advances and applications of EF process as a treatment step coupled with biological methods: the so-called bio-electro-Fenton (Bio-EF) process, which brings together the high oxidation power of EF and cost-effectiveness of biological methods.