The treatment of chemical high-salt wastewater by ED-MVR coupling technics and its energy consumption analysis

Abstract

In this study, electrodialysis mechanical vapor recompression (ED-MVR) coupling technics that could recycle the salt and the freshwater from the wastewater was put forward to treat the chemical wastewater with high salt. In order to make sure the economic feasibility of the ED-MVR coupling technics, the energy consumption was calculated by the theoretical model. Three parameters (the concentration of the feed, the concentration of the concentrated solution by ED, and the pressure of the evaporator) were researched to provide scientific guidance for the process optimization. In this work, the foremost factor found out during the analysis of energy consumption is the feed concentration which decides the scope of the ED-MVR process. When the concentration is lower than 12%, the technology reveals its advantages comparing with the stand-alone MVR process. At the same time, the energy consumption of the ED-MVR process decreases with the increase of the enrichment concentration. Also, the energy consumption of the MVR stage is influenced by the pressure of the evaporator. From the analysis, new thinking to deal with the chemical high-salt wastewater is provided by the ED-MVR coupling technics.