Energy Efficiency Assessment of the Electrodialysis Process in Desalinating Rest Area Water Runoff

The efficient use of energy is a sign of conscious environmental responsibility. Sustainable management also refers to water resources, where emphasis is placed on the possibility of retaining rainwater at the point of the precipitation occurrence. This article focused on the reuse of runoff from a rest area (RA) along the expressway, wherever drinking water quality is not required. The runoff from RAs can be significantly contaminated due to the traffic-related issues. The objective of this article was to evaluate the energy efficiency of preliminary treatment of raw meltwater from a selected rest area using electrodialysis for Cl− and Na+ removal. The treatment was carried out under various conditions, including different solution temperatures (20 °C and 30 °C) and electric voltages (10 V, 20 V, 30 V). The energy efficiency assessment was preceded by a characterization of runoff quality and the analysis of pollutant removal efficiency in the electrodialysis process. The most energy-efficient variant was characterized with the 0.097 Wh/(mg/L) energy expenditure ratio and 93% efficiency removal for Cl− and 0.147 Wh/(mg/L) and 90% for Na+. In this variant, the permissible Cl− and Na+ concentrations limits were achieved after 27 min with an energy consumption of 57 Wh. In general, the observed highest energy efficiency occurred at the beginning of the electrodialysis process and decreased over time.