填埋场环境恶臭气体污染物关键致臭物质及致臭机制研究

Due to the increase of municipal solid waste in China, malodor pollution caused by hydrogen sulfide, ammonia, and VOCs at landfills is becoming increasingly acute. Hence, the analysis and abatement of landfill odor are significant. Determining the key odorants and the mechanism of odor by combining instrumental and sensory analysis is a hot spot. However, research on the mechanism of odor pollution for complex odorous mixtures is still limited by the lack of effective simplification method and research on the change of sensitivity of odor perception (Weber-Fechner slope k).. The present research is dedicated to developing an effective simplification method and analyzing the mechanism of complex odorous mixtures from landfills. Odor interaction effects between different substances in the landfill odorous air will be investigated, and odor omitting as well as odor recombination experiments will be conducted to analyze the contribution of each substance. Afterwards, an effective simplification method will be developed to select the key odorants from the complex odorous mixtures in the landfills. Furthermore, odor interaction effects between the key odorants and different reference substances will be investigated, to revise the Weber-Fechner slope of the key odorants which is influenced by the odor interaction effects. Finally, the mechanism of odor pollution at landfills will be explained by determining the key odorants and the change of the sensitivity of odor perception (k) in the odorous mixtures. By developing the simplification method and analyzing the odor pollution mechanism, the present research could provide instructions and suggestions for the analysis, prevention and abatement of odor pollution from typical sources such as landfills.

随着我国城市生活垃圾产量的不断增加，垃圾填埋场散发硫化氢、氨、VOCs等气体造成的恶臭污染问题日益突出，因此对其进行准确分析和有效防治具有重要意义。结合仪器分析和感官分析方法筛选混合恶臭污染物中的关键致臭物质并探索气味形成机制，已成为当前恶臭气味污染研究的热点。但是针对复杂恶臭污染物体系，仍缺乏有效的关键致臭物质筛选方法和嗅觉灵敏度变化特征分析，限制了致臭机制研究的进展。. 本项目拟选取典型垃圾填埋场作为研究对象，开展复杂气味污染物体系的降元方法和致臭机制研究，深入分析复杂混合物中不同组分间的气味相互作用，设计气味重构与缺失实验，建立合理有效的复杂体系降元方法，准确筛选复杂气味污染物中的关键致臭物质，并分析混合物中气味相互作用对关键物质嗅觉灵敏度变化的影响，揭示复杂气味污染物的致臭机制。本项目的实施将为填埋场等典型环境恶臭气味污染的分析、预防和精准控制提供重要的理论指导和技术支撑。

垃圾填埋场散发恶臭气体造成的气味污染问题日益突出，对其进行准确分析和有效防治具有重要意义。本项目针对北京市典型垃圾填埋场，分别在春夏秋冬四个季节采集填埋场内暴露作业区、覆膜区、覆土区三个主要散发源的恶臭气体，结合气相色谱质谱和动态稀释嗅辨仪测定填埋场恶臭气体的组分类型和浓度，以及气味浓度和气味强度，共检出了145种污染物组分，包括芳香族化合物、含氧化合物、含硫化合物、含氮化合物、卤化物、烷烃、烯烃和萜烯8类化合物，硫化氢、氨、苯、甲苯、乙苯、间二甲苯检出率超过60%。采用气味活度值方法筛选出正戊醛、正己醛、庚醛、辛醛、壬醛、癸醛、正己酸和苯酚、硫化氢、氨9种OAV>1的组分，以及二甲基二硫醚、α-蒎烯和柠檬烯等OAV<1但具有较大异味影响潜力的组分。各类组分的异味贡献规律为：含氧化合物（82.33%）＞硫化物（17.27%）＞芳香化合物（0.20%）含氮化合物（0.15%）＞烯烃（0.019%）＞烷烃（0.018%）＞萜烯（0.017%）。进一步测定了关键致臭物质的嗅觉灵敏度及其在气味相互作用影响下的变化程度，结果表明，以乙酸丁酯为参比物质进行混合时，戊醛的气味活度值系数均小于1，表明混合物中二者之间的气味相互作用为拮抗作用，且拮抗作用随戊醛OAV的增大而减弱。戊醛与乙酸丁酯混合后，其嗅觉灵敏度从1.90变为1.55，类似的，乙苯与4-甲基-2-戊酮混合后，嗅觉灵敏度从1.37变为1.20，二甲苯与4-甲基-2-戊酮混合后，嗅觉灵敏度从2.76变为2.55。混合前后气味物质的嗅觉灵敏度k发生改变，说明乙酸丁酯对戊醛有拮抗作用，而4-甲基-2-戊酮对乙苯、间二甲苯均为协同作用，在实际混合样品中气味物质产生气味刺激的能力发生改变，揭示了组分化学浓度、气味阈值、嗅觉灵敏度、气味相互作用影响下的混合恶臭气体致臭机制。