The performance and applicability study of a photovoltaic-driven electro-Fenton wastewater treatment system

•A new photovoltaic electric Fenton (PVEF) system was developed with a low energy consumption of 5.5 kWh/kg.•The performance of PVEF systems in different types of wastewater were evaluated.•The PVEF can replace the deep treatment process in wastewater treatment plants, reducing energy consumption by 803 kWh and carbon emissions by 305 t. In the current mainstream wastewater treatment technologies, electro-Fenton (EF) has been widely used as an advanced oxidation process for achieving deep degradation of organic pollutants without secondary pollution. However, the high energy consumption of EF has hindered its development to a certain extent. In this study, a photovoltaic(PV)-driven EF system is developed to incorporate photovoltaic energy into the EF system to efficiently degrade organic matter in sewage and reduce energy consumption and operating costs of sewage treatment. To fully evaluate the performance of the photovoltaic drive electro-Fenton degradation sewage (PVEF) system, we investigated the effects of system configuration, current density, and stirring speed on the degradation of methyl orange (AO7) by the PVEF system. After determining the optimal experimental conditions, we explored the treatment efficiency and feasibility of the system for three different types of pollutants. Laboratory scale experiments also confirmed the critical effects of current density and stirring speed on the energy consumption of degradation. Finally, PVEF technology replaces the advanced treatment process in the sewage treatment plant, and the energy consumption model is established based on the local dye sewage plant in Chengdu to evaluate its applicability in different regions. The experimental results show that the dual-cathode system reduced energy consumption by 24.9 % and increased degradation efficiency by 30 % compared to the conventional EF system·H2O2 generated under the optimal conditions is fully utilized, resulting in a removal rate of more than 95 % in 20 min for AO7. The optimal energy efficiency condition is determined when the current density is 3 mA/cm2 and the stirring speed is 1000 rpm, which reduces the system’s energy consumption. The degradation test results of different pollutants show that the system can realize the degradation of various pollutants. The simulation results of the sewage plant scale show that the PVEF system can reduce carbon emission by 305 t instead of the traditional advanced treatment process.