Management of solar energy to power electrochemical wastewater treatments

Abstract In this work, the management of photovoltaic (PV) energy, assisted by a redox flow battery (RFB), for powering an electrochemical advanced oxidation process (EAOP), is evaluated. The storage of surplus energy allows to extend the treatment time overnight and to increase the environmental remediation efficiency during the whole electrochemical treatment. Nevertheless, this work points out that it is important to evaluate the most suitable powering strategy to take advantage of the total solar energy produced. The energy supplied by the PV panels to each system depends on the electrical features of the electrochemical devices (electrooxidation reactor and the RFB) and, especially, on the connection between them (series or parallel). A straightforward coupling (without a targeted regulation of the energy distributed between the EAOP and the RFB) brings out a time-depending and uncontrolled powering. This type of strategy opposes to the smarter regulation of the energy between the EAOP and the RFB by means of a targeted powering to each device. Results show higher remediation degrees when both electrochemical devices are directly coupled in parallel, regardless of the operational mode used (straightforward or targeted) due to lower current densities lead to higher global performances for both electrochemical devices. Nonetheless, it is important to note that the green targeted powering notices higher remediations than the straightforward coupling when the system operates under parallel connection and a RFB control. The low current densities supplied to the RFB point out higher capacities and, consequently, the remediation treatment is extended. Those results shed light on interesting conclusions in terms of green energy use. Furthermore, this software tool allows by means of a simple predictive modelling to optime the operational conditions of electrochemical treatments powered by renewable energies and assisted by energy storage systems.