Dear Colleagues,

It is beyond all doubt today that climate change mitigation must be faced from a circular economy perspective. In this context, a waste-to-energy recovery approach has become a key strategy for the future, to meet the Sustainable Development Goals of Agenda 2030. Bio-electrochemical systems (BES) show great potential as a future technology due to their ability to convert wastewater in valuable products—electricity in the case of microbial fuel cells and hydrogen in microbial electrolysis cells. 

However, the development of BES is limited by two main constraints: high production costs and low process efficiencies. On one hand, the economic limitations are mainly connected to the use of precious metals as catalysts and expensive polymeric membranes. On the other hand, their performance may be limited due to (1) low power output, (2) insufficient pollutant remediation efficiency, (3) handmade fabrication methods, (4) no optimized design, (5) low repeatability and versatility, and 6) poor understanding of microbes–electrode and electron transfer mechanism. 

Therefore, a strong effort is required of the scientific community to overcome these challenges and to promote the development and the implementation of this technology.

In this Special Issue, we aim to gather emerging approaches and new developments focused on improving efficiency and cost optimization, in order to achieve the industrial scale-up of bioelectrochemical systems.

Original research and review articles are expected in this Issue.

Topics of interest for publication include but are not limited to the following:

• Innovative configurations of bioelectrochemical reactors;
• Cost-effective materials for electrodes and membranes;
• Platinum group metal-free catalysts or low catalyst loadings;
• Sustainable or low impact materials for electrodes, membranes, and catalysts;
• Efficient MFC pilot scale-up approaches;
• Design and configuration of MECs for sustainable hydrogen production;
• Low-cost processing and manufacturing techniques;
• MFC or MEC application to wastewater treatment;
• New approaches of ,modeling and simulation of bioelectrochemical systems;
• Technoeconomic analyses of microbial fuel cell fabrication or application. 

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