Integrated hydroponic bioelectrochemical wastewater treatment process for sustainable agriculture

Increasing global food demands put pressure on existing water resources for supporting water-intensive conventional agricultural systems. Hydroponic systems have emerged as a potential solution for addressing water resource utilization challenges. However, the nutrient solution used in hydroponics poses additional problems. In this research, an integrated hydroponic bioelectrochemical system facilitates simultaneous wastewater treatment, energy generation, and nutrient transport across the membrane for the hydroponic system. This configuration offers the potential to bolster crop growth by transferring valuable ions from treated municipal wastewater. A combined bioelectrochemical–hydroponic system treats municipal wastewater from the Portage Treatment Plant (Indiana) in the anode chamber via an energy-positive process while supporting lettuce growth in the cathode chamber. This is compared to a standard microbial fuel cell configuration with an air cathode. Both employ 1000-ohm resistors, cation exchange membranes (CEMs), and distilled water and wastewater as catholytes and anolytes, respectively. Plant growth in the integrated design is monitored and compared to a traditional hydroponic setup. Coulombic efficiency, chemical oxygen demand (COD), and total nitrogen removal efficiency, as well as power generation in both configurations, are evaluated. Nutrient transport pathways across the membrane and their applications to plant growth are discussed. The findings of this study provide insights into the potential of the innovative bioelectrochemical system for both wastewater treatment plants and modern agriculture in a circular economy framework.