The article compares different methods for removing nitrogen from landfill leachate. They tested three processes in lab experiments: combining nitrification and denitrification, nitritation-anammox, and nitrogen precipitation as magnesium-ammonium-phosphate. The combined nitrification/denitrification process had the highest nitrogen removal rate but required aeration and carbon source. The nitritation-anammox process also removed nitrogen efficiently without needing a carbon source. However, the nitrogen precipitation process was less effective and led to increased phosphorous levels in the effluent. Overall, the nitritation-anammox process was found to be the most cost-effective for meeting nitrogen removal requirements in leachate treatment.