Wastewater reuse using photo-Fenton process at neutral pH.

Abstract

The photo-Fenton process is an advanced oxidation technique used to remove contaminants present in wastewater. Although the optimal pH to carry out this process is acid (approximately between 2.8 and 3), it is also studied at neutral pH. This makes the process eco-friendlier since it is not necessary to acidify and then neutralize to be able to pour the effluents into the environment. In this work of bibliographic review, the process at neutral pH has been studied with both artificial and natural light, from articles that employed chelating agents to carry it out. With artificial light has been identified what affected the process and with natural light the optimal conditions have been determined to eliminate at least 80% of the contaminants of emerging concern (CECs). The optimal conditions to eliminate the CECs, determined using natural light, since it has been considered as a more sustainable option, have been 0.1 mM of iron, 1.47 mM of peroxide and the use of EDDS as a chelating agent with a molar ratio of 1:1 with iron. Once these conditions have been identified, a raceway pond reactor (RPR) has been designed for La Jonquera Wastewater Treatment Plant (WWTP). Four different reactors have been designed, varying conditions and the criteria to choose which one has been economical. This RPR is intended to treat the water that comes out of the biological reactors, with an area of 1,169 m2 and a liquid depth of 15 cm. Finally, a study has been carried out of the costs associated with the installation of this reactor in the WWTP, estimated at €218,597, considering only the installation of the reactor and the purchase of lands adjacent to the plant.