[Characterization of greenhouse gas emissions and stable isotopic composition of ammonia during industrial composting process].

Carbon dioxide (CO ₂ ), nitrous oxide (N ₂ O), methane (CH ₄ ) and ammonia (NH ₃ ) emitted during the composting of livestock and poultry waste are important gaseous atmospheric pollutants. However, most previous studies on compost-related anthropogenic emissions of these gases were based on small reactor composting. Our understanding of their in situ emissions during industrial composting remains extremely limited. In order to explore the influence of gas produced by industrial composting on regional environment, we monitored CO ₂ , CH ₄ , N ₂ O and NH ₃ emissions during industrial composting for 19 days and characterized the isotopic composition of emitted NH ₃ . On average, the emission rates of CO ₂ , CH ₄ , N ₂ O, and NH ₃ during the composting cycle were 86.8 g CO ₂ -C·d ^-1 ·m ^-2 , 9.8 g CH ₄ -C·d ^-1 ·m ^-2 , 3.7 mg N ₂ O-N·d ^-1 ·m ^-2 and 736.6 mg NH ₃ -N·d ^-1 ·m ^-2 , respectively. The contribution of CH ₄ to daily global warming potential (GWP) was the highest (65%), followed by CO ₂ , NH ₃ (indirect), and N ₂ O. Moreover, ammonia emitted from industrial compost had a mean δ ¹⁵ N value of -11.6‰±1.2‰ (range: -21.8‰--7.2‰). Overall, this study provided useful information for understanding greenhouse gas emission dynamics and characterizing atmospheric NH ₃ sources during composting process in livestock and poultry breeding areas.