Critical evaluation of electroactive wetlands: traditional and modern advances

In the field of sustainable wastewater management, electroactive wetlands (EW), or constructed wetland-microbial fuel cells (CW-MFC), are an emerging technology. With the growing problem of untreated wastewater, the emphasis must shift to decentralisation of wastewater treatment infrastructure, and CW-MFC can be an excellent choice. This review provides a chronologically organized account of the design and configuration of CW-MFCs developed between 2010 and 2023. The research on CW-MFC has mainly focused on material, positioning and number of electrodes; use of electroconductive media and filler materials; flow regime; algal-based CW-MFC and multistage setups. Compared to traditional constructed wetlands (CW) and microbial fuel cells (MFC), CW-MFCs have a number of advantages, including better treatment efficiency, faster organic matter utilisation, lower capital and land requirements and a smaller carbon footprint. However, there are some limitations as well, such as upscaling and viable electricity generation, which are covered in more detail in the article. Moreover, the economics of this technology is also evaluated. The microbiology of a CW-MFC and its influence on its performance are also elaborated. Recent advancements in this field in terms of design, configuration and performance are discussed. Finally, the knowledge gaps that must be addressed before this technique can be successfully implemented on a large scale are highlighted, along with specific recommendations. This article aims to advocate for EWs as an ideal decentralised wastewater treatment technique, while also shedding light on the areas that still need to be worked on.