Open SolWat System with Cooling of the Secondary Wastewater Effluent from a WWTP on the Front Surface of the Photovoltaic Module for efficient Energy Generation and Reclaimed Water Production

Abstract

Energy consumption in wastewater treatment plants (WWTP) is a critical part of their operation and maintenance costs, with tertiary treatments being one of the most energy demanding stages, although as they are not required by law, they are not usually included in the wastewater treatment line. In this research, a photochemical–photovoltaic hybrid system was developed and studied: Open SolWat, which allows solar disinfection of the water while cooling the temperatures on the front surface of the photovoltaic module by means of a thin layer of water flowing from the top, thanks to a pumping system. In comparison to the SolWat technologies studied so far, the improved system allowed better quality reclaimed water (RD1620/2007, R(EU)2020/741) to be obtained from the secondary effluent of a WWTP, with the simultaneous generation of energy. However, this time it also productively improved its energy efficiency (15–21%). The tests were carried out under a 4 h SODIS treatment with real sunlight. Therefore, the possible implementation of the system as a tertiary treatment of a WWTP is considered, as it could improve environmental sustainability and reduce energy consumption.

Keywords

• solar energy
• photovoltaics
• active water cooling
• reclaimed water