This study examines the impact of the chemical oxygen demand to nitrogen ratio (COD:N) on nitrous oxide (N2O) emissions
during N removal via a nitrite (NO2−) pathway for synthetic livestock wastewater treatment. Based on typical cycle operations,
1.07 ± 0.07% of the incoming N load was emitted as N2O at a COD:N ratio of 3:1. This was higher than the 0.83 ± 0.08%
emitted at a COD:N ratio of 6:1. The low COD:N ratio in the synthetic livestock wastewater may thus cause increased N2O
emissions. Nitrous oxide was emitted during both aeration and non-aeration periods; however, N2O emissions during aeration
periods were much higher than during non-aeration periods. Low dissolved oxygen levels, high NO2−-N concentrations and an
intermittent aeration strategy were the primary factors encouraging N2O emissions during synthetic livestock wastewater
treatment via the NO2− pathway.