工厂化堆肥温室气体排放和氨气同位素特征

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

畜禽废弃物堆肥处理过程中产生的二氧化碳(CO_(2))、氧化亚氮(N_(2)O)、甲烷(CH_(4))和氨气(NH_(3))等是重要的温室气体和大气污染物。但目前有关该过程气体排放的研究多基于室内小型模拟的反应器式堆肥,在工厂化堆肥条件下的原位气体排放监测较少。为探究工厂化堆肥产生气体对区域环境的影响,本研究对沈阳某堆肥厂畜禽废弃物堆体的气体排放进行了19 d的监测,并量化了排放氨气的自然丰度;N(δ^(15)N)特征。结果表明:堆置周期内,CO_(2)、CH_(4)、N_(2)O和NH_(3)的平均排放速率分别为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)和736.6 mg NH_(3)-N·d^(-1)·m^(-2)。温室气体日增温潜势(GWP)的贡献大小为CH_(4)>CO_(2)>NH_(3)(间接)>N_(2)O,其中CH_(4)贡献了65%。堆肥排放NH_(3)的δ^(15)N在-21.8‰~-7.2‰,平均-11.6‰±1.2‰。本研究结果可为区域畜禽废弃物堆肥过程中温室气体排放的核算及大气氨溯源提供数据支持。

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 meanδ^(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.