<p dir="ltr">This study investigates the optimization of nitrogen removal in wastewater treatment through a comparative analysis of conventional nitrification-denitrification (N/D) and partial nitritation-anammox (PN/A) processes integrated with anaerobic digestion (AD). Using Bio-Win 6.0 simulations, the research examined system performance across various operational conditions, including temperature ranges (15-35°C), dissolved oxygen levels (0.1-2.0 mg/L), and total Kjeldahl nitrogen concentrations (40-1000 mg/L). Results demonstrated that the PN/A-AD system achieved superior nitrogen removal efficiency (up to 97.5% at 100 mg/L TKN) compared to conventional N/D processes, particularly in treating high-strength nitrogen wastewater. The PN/A system maintained 54.3% removal efficiency even at 1000 mg/L TKN, while requiring less energy (4,614 kW versus 4,682 kW) and producing significantly less sludge (0.57 kg/kg versus 8.07 kg/kg nitrogen removed). Temperature significantly influenced system performance, with optimal conditions observed at 35°C and DO levels between 1-1.5 mg/L. Sensitivity analysis revealed system stability across multiple operational parameters, suggesting robust performance in realworld applications. This research provides valuable insights for designing and optimizing nitrogen removal processes in wastewater treatment plants, particularly for facilities targeting energy efficiency and reduced operational cost.</p>