Bioelectricity production using shade macrophytes in constructed wetlands-microbial fuel cells

The coupling of constructed wetlands (CW) to microbial fuel cells (MFC) has become a promising hybrid technology due to its high compatibility to generate electricity and remove pollutants from wastewater. In the present study, the bioelectricity production generated from constructed wetlands-microbial fuel cells (CW-MFCs) was evaluated using four species of shade macrophytes: Aglaonema commutatum, Epipremnum aureum, Dranacaena braunni, and Philodendron cordatum. The CW-MFCs were operated in a continuous upflow mode with a hydraulic retention time (HRT) of 4 d. The systems were fed with synthetic water without an external carbon source. The bioelectrochemical systems were operated under diffuse radiation conditions (shadow). Philodendron cordatum was the macrophyte species that produced a maximum voltage of 103 mV, with a power density of 12.5 mW/m(2). High voltages were obtained when the diffuse radiation in the CW-MFCs was 3000-4000 mu mol(.)m(2)/s. The maximum production of root exudates was 20.6 mg/L as total organic carbon for the Philodendron cordatum species. Philodendron cordatum was the macrophyte species that obtained high conversion efficiency (0.0014%), compared to other macrophyte species (< 0.0008%). In the CW-MFCs systems it was observed that the bioelectricity production was mainly due to the quantity of the root exudates released into the rhizospheres of the plants.

Automated summary

The coupling of constructed wetlands to microbial fuel cells is a promising hybrid technology for generating electricity and removing pollutants from wastewater. This study evaluated the bioelectricity production from constructed wetlands-microbial fuel cells using different species of shade macrophytes, and found that Philodendron cordatum was the most efficient in terms of voltage and power density.