Microbial Desalination Cells (MDCs): Technological Potential, Operational Limitations and Scale-Up Perspectives

Microbial desalination cells (MDCs) are emerging bioelectrochemical systems that integrate wastewater treatment, seawater desalination and energy recovery within a single process. By converting organic matter into electrical energy while driving ion migration from saline streams, MDCs offer a sustainable complement to conventional desalination technologies. Recent advances in reactor design, electrode materials, ion-exchange membranes and operating strategies have improved desalination efficiency, organic matter removal, pH stability and energy recovery. Nevertheless, practical application remains constrained by low volumetric productivity, membrane fouling, limited long-term stability, modest power generation and uncertain economic feasibility under realistic wastewater conditions. This review provides a critical assessment of MDC technology beyond conventional configuration-based comparisons. Using the three-chamber MDC as a reference platform, it analyses how electrodes, membranes and operational parameters interact to determine overall performance, highlighting the mechanisms that limit efficiency. It also evaluates performance metrics, diagnostic methods, cost considerations, scale-up challenges and industrial applicability. Emphasis is placed on the realistic role of MDCs, not as stand-alone desalination technologies, but as integrated pre-treatment units for processes such as reverse osmosis. By combining technical, operational and economic perspectives, this review identifies key future research priorities for scalable application, including advanced modelling, material optimisation and robust long-term system integration strategies.