Bipolar Membrane Electrodialysis for Nutrients Separation and Recovery from Wastewater

Bipolar membrane electrodialysis (BMED) is an electro-membrane separation technology used for over 20 years to treat liquid wastes, including wastewater from various industrial processes, municipal wastewater, and animal farms. This technology has been developed for its ability to dissociate H2O into H+ and OH− ions and to convert cations and anions in the feed solution into bases and acids, respectively, by applying an electrical potential. In comparison with alternative treatment technologies, BMED has some advantages, such as no need for chemical reagents, high degrees of efficiency, and straightforward operational procedures. However, BMED has been limited by a high level of preparation expense for BMs, membrane deposition, and ion loss during operation. This review mainly describes the principles and designs of BMED, their compositions along with their advantages and disadvantages, the membrane fouling and cleaning, and also the trend of their application in wastewater treatment. Finally, the results on nutrient recovery by BMED show that the performance of BMED depends on the nature of the ion exchange membranes used, the composition of the sample solution, the process conditions, and the configuration of the membrane stack.