Optimal Treatment of Hypersaline Industrial Wastewater via Bipolar Membrane Electrodialysis

The wastewater from a fluid catalytic cracking refinery is difficult to treat because of its high salt content. An optimized bipolar membrane electrodialysis (BMED) strategy to dispose of this wastewater is proposed, and its effect is studied via a combination of experiments and simulations. First, the wastewater generation process is simulated by Aspen HYSYS software to identify the main pollutants in wastewater. Second, the influences of current density and operation time on the treatment efficiency and energy consumption are studied experimentally. This BMED process is then performed by custom models in Aspen Plus software based on experimental data. Finally, the solar organic rankine cycle (SORC) is used to optimize the power supply for BMED. The simulation results show that the mass fraction of sodium sulfate in disposed wastewater decreases from 8.000% to 0.370%, the mass fraction of sulfuric acid production is 7.656%, and that of sodium hydroxide is 6.431%. The SORC produces 2.880 kW of electricity to support the BMED process. Compared with conventional methods, the BMED SORC disposal of high-salt wastewater not only achieves the expected treatment effect but also produces additional valuable substances. This process is therefore facile to operate in a green and effective way and demonstrates potential large-scale applications in wastewater treatment.