Critical assessment of advanced oxidation processes and bio-electrochemical integrated systems for removing emerging contaminants from wastewater

The remediation of emerging contaminants (ECs) of concern, such as personal care products, antibiotics, endocrine-disrupting chemicals (EDCs), surfactants, pesticides, etc., is the need of the hour. Conventional wastewater treatment technologies such as the activated sludge process, trickling filter, constructed wetlands, coagulation and flocculation, adsorption, etc. are not designed to remove trace recalcitrant contaminants. This necessitates the need to devise novel technologies specifically to target bio-refractory microcontaminants present in wastewater. In this context, the present review article focuses on the remediation of ECs through advanced oxidation processes (AOPs) and integrated bio-electrochemical systems (BESs). In this critical assessment, the detailed mechanism, degradation efficiency, comparison, techno-economic and life cycle analysis, relative merits and demerits, and challenges and future prospects of electrochemical technologies (ETs) and integrated BESs are presented. The integrated BESs and hybrid AOPs have shown enormous potential for the degradation of ECs because of their low operational cost and environmental compatibility. Even though individual ETs are also promising, higher operational cost hinders their real-life applications. Therefore, more scaled-up investigations and efforts to overcome these challenges are required to accelerate the commercialization of these technologies.