Bio-Electrochemical Evaluation of Constructed Wetland-Microbial Fuel Cells for Wastewater Treatment and Simultaneous Bioenergy Recovery

Addressing the urgent need for sustainable solutions in stormwater and wastewater treatment is a global concern, this study explores innovative methods for effective wastewater management and simultaneous resource recovery from the process. Traditional "grey infrastructure" techniques often fall short, leading to flooding, pollution, and overburdened treatment facilities. Additionally, conventional water treatment methods typically focus on pollutant removal, neglecting the potential for valuable resource recovery from wastewater streams. With increasing water scarcity, there is a great need for a paradigm shift from only pollutant removal from wastewater to simultaneous resource recovery in the wastewater treatment processes.

Using the positivism approach, this research investigated the integration of constructed wetlands (CWs) with microbial fuel cells (MFCs) for dual purposes: enhancing wastewater treatment and generating bioenergy. A lab-scale trial with four CW configurations used a downhill vertical flow arrangement. These configurations incorporated aggregates, graphite plates, copper wires, granulated activated carbon, and stainless steel wire meshes to function as anodes and cathodes.

Stormwater samples were tested for colour, turbidity, pH, and nitrate levels before and after treatment in the CW rigs. Results showed that influent stormwater quality significantly impacted effluent parameters, with higher influent levels resulting in higher effluent values. Notably, the pH levels in the effluent were mostly alkaline, which is suspected to have hindered power production in the CW-MFC systems. However, nitrate concentrations in the effluent were significantly reduced, aligning with studies demonstrating CWs' effectiveness in removing wastewater pollutants.

This study highlights the potential of CW-MFC systems in achieving sustainable wastewater management and resource recovery, contributing to global sustainable development goals.