Application of solar photo-Fenton in raceway pond reactors: A review

This work critically reviews the present knowledge about the use of Raceway Pond Reactors (RPR) to treat municipal wastewater treatment plant (MWWTP) secondary effluents by solar photo-Fenton process. The possibility of using RPR to treat industrial wastewater, which has been barely explored, is also reviewed. Initially, the general concepts and operation principles of RPR are described as well as their origin for photo-Fenton applications. Then, the main results and advances related to contaminants of emerging concern (CECs) removal, inactivation of microorganisms, industrial wastewater treatment and kinetic modelling are presented. Key aspects such as the impact of liquid depth, the continuous flow operation feasibility, the increase in treatment capacity, and the kinetic modelling are addressed along the review. At the end, main challenges and research gaps are identified, which should be the focuses of future research.