Resource Recovery of Corn Stover in Water Treatment: Nitrate Removal from Simulated Groundwater

• • Mixed corn stover tissues and husk achieved >98% nitrate removal across four cyclic denitrification runs, with total nitrogen removal capacities of 39.30 mg/g and 39.95 mg/g, respectively, demonstrating sustained performance for groundwater remediation. • • DOC release from mixed tissues and husk exhibited stable slow-release kinetics, yielding high carbon utilization efficiencies of 203.99 mg TN/g organic carbon and 182.41 mg/g, respectively, indicating effective electron donor supply for denitrification. • • Byproduct accumulation (NO2-N and NH4-N) remained below 2 mg/L in the best-performing systems, ensuring minimal secondary pollution and compliance with stringent water quality standards. • • Structural equation modeling revealed that carbon source type indirectly controls total nitrogen removal via DOC-mediated effects on pH, conductivity, and nitrogen transformation pathways, providing a mechanistic basis for optimizing carbon source selection in bioreactors.