Electrochemical treatment of plastic industry wastewaters powered by photovoltaic solar energy

¹ Democritus University of Thrace, Hephaestus Laboratory, Department of Chemistry, School of Science, Kavala, Greece
² Democritus University of Thrace, Department of Computer Science, Kavala, Greece
³ Democritus University of Thrace, Hephaestus Laboratory, Department of Physics, School of Science, Kavala, Greece
⁴ Democritus University of Thrace, Department of Environmental Engineering, Xanthi, Greece

^* Corresponding author: ifantidi@physics.duth.gr

Abstract

Electrochemical processes combined with renewable energy sources are considered sustainable and efficient for wastewater treatment. The combined photovoltaic – electrochemical (PV-EC) method can produce electrolytic hydrogen and purify industrial wastewaters by combining solar energy with electrocoagulation and electrooxidation processes. The PV-EC system's adaptability resides in its capacity to modify wastewater flow rate in response to the PV array's current intensity and instantaneous solar radiation. Operating parameters that affect process efficiency include wastewater flowrate, applied current intensity, electroprocessing time and solar irradiance were examined and optimal conditions were identified. The experimental results revealed that the initial chemical oxygen demand (COD) of 19 460 mg L^-1 of the plastic industry wastewater, were decreased to 8000 mg L^-1, after 2 h electroprocessing time using iron or aluminium electrodes at 600 mA current intensity. Further increase of COD removal efficiency was not possible either with increasing processing time, current intensity or using electrooxidation process. The results of our study indicate that the electrochemical treatment can reduce COD from wastewater generated during the production of plastic products. Moreover, the proposed method is applicable in decentralized areas without access to the electricity grid.