Overview of Sustainable Water Treatment Using Microbial Fuel Cells and Microbial Desalination Cells

Global water scarcity and pollution are among the most severe challenges, affecting the lives of over 2.2 billion people and leading to a projected water demand that will exceed supply by 40% by 2030. Even though reverse osmosis and thermal desalination are commonly adopted water governance solutions, with energy consumption rates reaching up to 10 kWh/cubic meter of water, they remain economically unfeasible for most countries. Therefore, with rapid population growth and industrialization, high operation costs further limit the adoption of the traditional water treatment technologies. However, microbial fuel cells (MFCs) and microbial desalination cells (MDCs) are an innovative solution due to their ability to treat wastewater, desalinate water, and generate bioelectricity simultaneously. The recent advancements in MFCs have enabled the achievement of over 3 W/m 2 of power density, while desalination efficiencies in MDCs have surpassed 63%, reducing total energy consumption by more than 40% when compared to traditional methods. The innovative use of electrode materials, like graphene and carbon nanotubes, has led to a 40% faster electron transfer rate, further increasing the efficiency of energy recovery. Moreover, the innovative integration of artificial intelligence (AI) and machine learning (ML) optimized MFCs and MFC operations, leading to a cost reduction of up to 20% through the real-time monitoring of PMDCs. The main challenges, such as the high capital costs and membrane fouling, were also considered, with the system scalability being the recurring concern. Thus, the current reports suggest that MFCs and MDCs would reduce wastewater treatment costs by 30% if applied on a large scale in the future.