Conference on Environmental Science and Technology

In recent decades, the production of saline wastewater has increased significantly as various industries, including tanneries, the food industry, oil and gas, and pulp and paper, contribute to its generation (Alam et al., 2022). However, saline wastewater can have a negatively impact on coastal ecosystems and the microorganisms employed in wastewater treatment plants. Therefore, the EU has adopted strict disposal regulations and the Scientific Committee has focused its research efforts on methods to utilize this wastewater that align with the EU's circular economy strategy. Bipolar Electrodialysis (BED) is an innovative separation process in which electricity drives the exchange of anions (Cl-, SO4-2, etc.) and cations (Na+, K+, etc.) through positively and negatively charged membranes, respectively, whereas bipolar membranes (BPM) are applied with the aim to split H2O molecules into H+ and OH-, enabling the production of alkaline and acidic solutions from saline wastewater. In this study, a bipolar electrodialysis system (BED) was used to produce NaOH and HCl from saline wastewater from the pulp and paper industry (Essity, France) and the steel industry (Huttenwerke Krupp Mannesmann GmbH). Initially, a two-chamber BED system (BED1-2, PCCEll GmbH) was employed to evaluate the performance of commercial cation (CEM) and anion exchange membranes (AEM) with respect to the production of NaOH and HCl from synthetic NaCl solutions. Subsequently, the primary operating parameters of the process were optimized and finally, the BED1-2 system was scaled up to a three-chamber system (BED1-3), in which the simultaneous production of HCl and NaOH from synthetic and real wastewater was examined. This work was performed in the context of the CORNERSTONE project that received funding from the European Union’s Horizon Europe Research & Innovation framework programme under Grant Agreement No 101138504.