Exploring the Life Cycle Environmental Performance of Different Microbial Fuel Cell Configurations

Drastic global population and economic growth have escalated energy and water crises across the world. The overconsumption of energy and water resources without proper planning has entailed adverse environmental impacts. The emergence of microbial fuel cell (MFC) as a bio-electrochemical system (BES) for wastewater treatment and electricity generation shows potential as a prospective solution for the crises. To date, there is no study focused on the environmental impact comparison of different MFC configurations from a life cycle perspective. In this study, the environmental performance of five common MFC configurations (MFC 1: air-cathode MFC; MFC 2: H-type MFC; MFC 3: U-type MFC; MFC 4: flat MFC; and MFC 5: modularized MFC) from the construction stage to the operational stage are being investigated and compared via life cycle assessment methodology. MFC 1, MFC 3, and MFC 4 are single chamber reactors, while MFC 2 and MFC 5 are double chamber reactors. Data collected for this study are mainly sourced from peer-reviewed journal articles and evaluated using the ReCiPe 2016 impact assessment method in SimaPro 9.0 software. The results reveal that the MFC 4 induces the highest overall environmental burdens due to the high hydraulic retention time for wastewater treatment. The other options share significantly low and similar overall environmental burdens. It is also found that the energy consumption from MFC options accounts for 60-90 % of environmental loads in wastewater treatment. The COD level of the treated effluent in all options meets the discharge standard, but the nitrogen and phosphorus content level have to be further reduced to minimise the eutrophication risk to the aquatic ecosystems. This study provides data-driven insights to the renewable energy policymakers and wastewater treatment stakeholders on the environmental potential of different MFC configurations in relieving energy and water crises.