Concentrating Nitrogen Waste with Electrodialysis for Fertilizer Production
Mohammed Tahmid, Hyuck Joo Choi, Sai Tarun Ganapavarapu, Joseph K. Scott, Marta C. Hatzell
Abstract
High Resolution Image Download MS PowerPoint Slide Recovery of nitrogen from wastewater presents a unique opportunity to valorize waste and contribute to a more circular nitrogen economy. However, dilute solution separations are challenging for most state-of-the-art separations technologies. This often results in technologies having low concentration factors that result in low-value products (e.g., < 1 wt % N). Here, we demonstrate how a cascading electrodialysis system combined with a hollow fiber membrane contactor (ED+HFMC) system can achieve efficient recovery of ammonia from simulated centralized animal feeding operation (CAFO) wastewater. The integrated system achieved an overall concentration factor of ∼200× (∼40× in ED and ∼5× in HFMC). This resulted in a ∼10 wt % NH 4 + -N fertilizer product. The specific energy consumption (SEC) for the three stages of the ED was 1.89–6.14 kWh/kg NH 4 + -N, which is lower than that of the Haber–Bosch process (8.9–19.3 kWh/kg N). Operating costs were <$0.90/kg NH 4 + -N for each of the electrodialysis stages and NH 3 stripping. This integrated ED+HFMC system holds promise for the recovery of ammonia from dilute feedstreams as the ED+HFMC achieves high concentration factors and has low energy demand.