Conference on Environmental Science and Technology

Nitrous oxide (N₂O), a potent greenhouse gas with a global warming potential 300 times greater than CO₂, is increasingly recognized as a critical environmental challenge in wastewater treatment. Accurate measurement and mitigation of N₂O emissions are essential to minimize the climate impact of these systems. One of the factors influencing N₂O emissions is the aeration strategy. Aeration strategy plays a pivotal role in the efficiency and environmental footprint of wastewater treatment processes. This study explores the effects of three distinct aeration regimes—continuous aeration, intermittent aeration with 10-minute cycles (10 min aerated/10 min non-aerated), and intermittent aeration with 30-minute cycles (30 min aerated/30 min non-aerated)—on nitrogen removal efficiency and N₂O emissions. The experiments were conducted on activated sludge and wastewater samples collected from municipal WWTP designed for simultaneous carbon, nitrogen, and phosphorus removal. The results revealed significant differences in nitrogen removal efficiency and N₂O emission factors between the strategies. Continuous aeration achieved a nitrogen removal efficiency of 25% but resulted in the highest N₂O emission factor of 4.79%. The 30/30 intermittent aeration strategy improved nitrogen removal efficiency to 49%, with a lower emission factor of 3.35%. In contrast, the 10/10 strategy achieved a nitrogen removal efficiency of 39%, with an emission factor of 4.11%. These findings highlight the trade-offs between nitrogen removal efficiency and N₂O emissions under different aeration strategies. The 30/30 strategy demonstrated the most balanced performance, offering higher nitrogen removal efficiency and reduced emissions compared to the other strategies. By minimizing N₂O emissions, WWTPs can significantly reduce their carbon footprint while maintaining compliance with stringent effluent quality standards. This research offers valuable insights into operational adjustments that municipal treatment facilities can adopt to align with global sustainability goals.