A review of microbial fuel cell prototypes, their efficacy in wastewater treatment and the contextual situation for Zimbabwe

Accelerated global human population growth and the corresponding increased urbanisation and industrialisation have resulted in increased manufacturing of goods, and production and loading of domestic and industrial wastewater overwhelming conventional wastewater treatment plants (CWTPs). The net result has been the release of untreated and partially treated domestic wastewater into water systems posing human health hazards and disturbing aquatic habitat integrity. Considering the severe challenges of wastewater treatment not only in Zimbabwe but in Africa and the world in general, it is prudent to assess the microbial fuel cells (MFCs) as an alternative wastewater treatment method for the CWTPs that have failed to operate efficiently. This purposive literature scoping review aimed to: (a) Examine the concept design and operational efficacy of microbial fuel cells (MFCs), (b) Examine the MFC operational system (c) Outline in brief the evolutionary history and assess the existent prototypes and (d) Establish the drivers and barriers for the uptake of microbial fuel cells (MFCs) from a global and local, Zimbabwe, context. Few prototypes have been utilized in real-world systems; with the majority of them being laboratory-scale based. Although MFCs are effective at treating wastewater, scaling them up is still difficult due to their low power generation. Nonetheless, MFCs' simultaneous wastewater treatment and power generation, low carbon footprint, and reduced sludge production are the main drivers behind their adoption. However, capital and maintenance costs and upscaling remain the major challenges in adopting MFC technology. If MFCs are to be used in developing nations like Zimbabwe, further studies should focus on low-cost materials that guarantee maximum power generation and effective wastewater treatment. To ensure effective wastewater treatment, MFCs should be compatible, and integrated with currently utilized sustainable wastewater treatment systems.