Performance of pilot-scale horizontal subsurface flow constructed wetland coupled with a microbial fuel cell for treating wastewater

This work presents a new hybrid technology for treating wastewater along with electricity generation. The main objective of this work was to integrate a microbial fuel cell (MFC) into a horizontal subsurface constructed wetland (HSSF-CW-MFC) at a pilot scale for improving the wastewater treatment performance of HSSF-CW. The HSSF-CW-MFC was tested on three different organic loading rates: 0.15, 0.30, and 0.52 kg COD/m³/d at a set hydraulic retention time. The HSSF-CW-MFC was further studied for establishing the influence of electron transfer using conductive material (artificial electron acceptor) on wastewater treatment performance. During the efficient electron transfer (system run in closed-circuit operation), 33.7% higher chemical oxygen demand (COD) removal was achieved in comparison to the hindered electron transfer (system run in open circuit) condition. The results illustrate that efficient electron transfer from bottom anaerobic zones to the aerobic zone of the HSSF-CW helps in enhancing the treatment performance. The maximum power and current densities achieved were 11.67 mW/m³and 17.15 mA/m³, respectively.