Recovery of Wastewater Nitrogen for Solanum lycopersicum Propagation

Recovery of wastewater nitrogen and recycle into plant biomass was demonstrated with a anaerobic ion exchange (AN-IX) reactor and hydroponic cultivation of Solanum lycopersicum. A Maryland AN-IX prototype was operated for 355 and confirmed > 95% total nitrogen nitrogen removal at 14–22 °C temperature and clinoptilolite capacity of 0.81 meq NH4+-N/g. Sequential breakthrough of NH4+ was successfully predicted with a 1-D solute transport model, suggesting that NH4+ capture within AN-IX is amenable to rational process design. Solanum lycopersicum (cherry tomato) was cultivated in fill-and-drain hydroponic culture with AN-IX clinoptilolite as sole nitrogen source. Spent clinoptilolite supported greater increases in plant canopy volume and flower and fruit production than synthetic fertilizer or clean, unused zeolite. Ammonium and nitrate increased significantly in the recirculating nutrient medium with spent clinoptilolite, presumably by microbially mediated NH4+ desorption that occurred auto-catalytically without inoculation. This study provides proof-of-principal of local-scale recycling of wastewater nitrogen by AN-IX recovery and direct plant propagation in spent AN-IX media.