The plant-enhanced bio-cathode: Root exudates and microbial community for nitrogen removal

A plant bio-electrochemical system (PBES) was constructed for organic pollutant removal and power generation. The bio-cathode, composed of granular activated carbon (GAC), stainless wire mesh and a plant species (Triticum aestivum L.), was able to catalyze cathodic reactions without any requirement for aeration or power input. During the 60-day-long operation, an average voltage of 516 mV (1000 Omega) and maximum power density (P-max) of 0.83 W/m(3) were obtained in the PBES. The total nitrogen removal and total organic carbon removal in the PBES were 85% and 97%, respectively. Microbial community analyses indicated that bacteria associated with power generation and organic removal were the predominant species in the bio-cathode, and plant-growth-promoting rhizobacteria were also found in the PBES. The results suggested that the coupling of plants with the GAC cathode may enhance the organic-matter degradation and energy generation from wastewater and therefore provide a new method for bio-cathode design and promote energy efficiency. (C) 2018 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.