Enhanced wastewater treatment and electricity generation using stacked constructed wetland-microbial fuel cells

Water pollution and energy production are major issues in the context of climate change, urbanization and industrialization. There is need for cost-effective and sustainable processes for wastewater treatment. Here we designed a novel system made of a stack of 12 vertically-arranged constructed wetlands coupled with microbial fuel cells. Performance was evaluated in terms of chemical oxygen demand (COD) removal, NH4+-N, NO3--N, and PO4-3 removal efficiency, and electricity generation. The results reveal that the efficiency of COD removal increased gradually with decreasing external resistance, reaching 98.5% at 0.08 k omega. The maximum removal efficiency was 90.4% for NH4+-N at 15 k omega and 86.9% for NO3-N at 0.08 k omega. The maximum power density reached 30.85 mW/m(3) at 15 k ohm.