Nitrous oxide production during nitrification from organic solid waste under temperature and oxygen conditions

Landfill aeration can accelerate the biological degradation of organic waste and reduce methane production; however, it induces nitrous oxide (N₂O), a potent greenhouse gas. Nitrification is one of the pathways of N₂O generation as a by-product during aerobic condition. This study was initiated to demonstrate the features of N₂O production rate from organic solid waste during nitrification under three different temperatures (20°C, 30°C, and 40°C) and three oxygen concentrations (5%, 10%, and 20%) with high moisture content and high substrates’ concentration. The experiment was carried out by batch experiment using Erlenmeyer flasks incubated in a shaking water bath for 72 h. A duplicate experiment was carried out in parallel, with addition of 100 Pa of acetylene as a nitrification inhibitor, to investigate nitrifiers’ contribution to N₂O production. The production rate of N₂O ranged between 0.40 × 10⁻³ and 1.14 × 10⁻³ mg N/g-DM/h under the experimental conditions of this study. The rate of N₂O production at 40°C was higher than at 20°C and 30°C. Nitrification was found to be the dominant pathway of N₂O production. It was evaluated that optimization of O₂ content is one of the crucial parameters in N₂O production that may help to minimize greenhouse gas emissions and N turnover during aeration.