污泥堆肥及其土地利用全过程含氮气体(NH3, N2O, NO)的排放特征及其控制研究

Composting and land application of compost is and will be one of the major approaches for sludge treatment and disposal of China in the future. However, there is extremely lack data of NH3, N2O and NO emissions from the full process of sludge composting and compost land application, resulting in great difficulty to meet demands of greenhouse gas reduction and nitrogent conservation. Therefore,it is imperative to carry out such kind of research.In this study, three gases-containing nitrogen such as NH3, N2O and NO are selected, and their emission characteristics and factors from the full process of sludge composting and compost land application will be determined through field investigation. A revised model will be thus established for NH3, N2O and NO emissions calculation and scenario analysis in China. Technologies for reducing NH3, N2O and NO emission will be developed and integrated, through adjusting C/N ratio,moisture content in the stage of pretreatment, optimizing aeration and turning in sludge composting,and screening nitrification inhibitor during land application of sludge compost based on synergetic control theory. Through investigating links of nitrogen transformation, functional microbial community such as ammonification bacteria, nitrifying bacteria anddenitrifying bacteria and their genes (amoA, nirK, nirB, norB) using advanced analysis methods such as isotope tracer and real RT-qPCR methods, mechanisms of NH3, N2O and NO emission from the whole process of sludge composting and compost land application will be revealed in order to provide scientific and technological support for greenhouse gas reduction and air pollution control in sludge treatment and utilization in China.

污泥堆肥及其土地利用是今后我国污泥处理与资源化利用的主要发展方向，但我国极端缺乏该过程的NH3,N2O,NO排放基础数据，难以满足温室气体和污染气体减排的需求，开展该方面的研究势在必行。因此，本项目以三种含氮气体(NH3,N2O,NO)为对象，明确污泥堆肥及其土地利用全过程的NH3,N2O,NO排放特征与排放因子。围绕氮素转化过程、功能菌群(氨化菌、硝化菌、反硝化菌)和功能基因(amoA,nirK,nirB,norB)，研究氮素转化与NH3， N2O,NO排放的相互关系，揭示全过程的N2O,NH3,NO排放机制。从前端(预处理)、过程(堆肥过程)和末端(土地利用)控制入手，研发实现全过程NH3, N2O和NO减排的协同控制关键技术，探讨不同情景下我国典型区域污泥堆肥及其土地利用全过程的NH3、N2O和NO排放减缓效益，为我国今后污泥处理与资源化利用的温室气体和污染气体减排提供科技支撑。

污泥堆肥及其土地利用是今后我国污泥处理与资源化利用的主要发展方向，但我国极端缺乏该过程的NH3,N2O,NO排放基础数据，难以满足温室气体和污染气体减排的需求，开展该方面的研究势在必行。因此，本项目以三种含氮气体(NH3,N2O,NO)为对象，明确污泥堆肥及其土地利用全过程的NH3,N2O,NO排放特征与排放因子。围绕氮素转化过程、功能菌群(氨化菌、硝化菌、反硝化菌)和功能基因(amoA,nirK,nirB,norB)，研究氮素转化与NH3，N2O,NO排放的相互关系，揭示全过程的N2O,NH3,NO排放机制。从前端(预处理)、过程(堆肥过程)和末端(土地利用)控制入手，研发实现全过程NH3, N2O和NO减排的协同控制关键技术，探讨不同情景下我国典型区域污泥堆肥及其土地利用全过程的NH3、N2O和NO排放减缓效益。取得污泥不同堆肥工艺、不同季节的温室气体和氨气排放特征。 通过通风优化设计可以降低污泥堆肥中氨气累积排放量约5%，减少温室气体排放当量0.121kg eCO2；通过添加物料湿重1%的沸石粉可以减少5%堆肥过程中温室气体的累积排放；污泥堆肥品土地利用过程NH3仍是主要的N素损失源，相对CK处理净N素损失占污泥堆肥品TN含量的7.22%；N2O平均排放通量相对净损失为污泥堆肥品TN含量的0.524%；生命周期评价分析表明，获得污泥堆肥及土地利用全生命周期增温潜势及排放因子分别为328.41 kg eCO2/tDS。其中，污泥处理系统以土地利用（45.88%）和供电(42.04%)为主要贡献，污泥处理系统以化石燃料CO2和N2O为主要的GHG排放。我国三种典型土壤中氮素转化功能菌群为Nitrososphaera，Nitrosospira和Nitrospira，以AOA为主，污泥堆肥对黄土中功能菌群的扰动较小，而黄土中关键功能基因amoA, nirS, narG和nosZ的丰度高于红土和黑土中，这说明黄土中氮素转化更为活跃，也是温室气体排放的热点区域。