Dep. of Aricultural Engineering, Faculty of Agricultural Sciences, Aarhus University, 8830 Tjele, Denmark.
J Environ Qual. 2010 Apr 13;39(3):1085-96. doi: 10.2134/jeq2009.0184. Print 2010 May-Jun.
Biological air filters have been proposed as a cost-effective technology for reducing odor emissions from intensive swine production facilities. In this work we present results from the application of membrane inlet mass spectrometry (MIMS) for continuously monitoring the removal of odorous compounds in biological air filters. The sensitivity and selectivity were tested on synthetic samples of selected odorous compounds, and linearity and detection limits in the lower ppb range were demonstrated for all compounds tested (methanethiol, dimethyl sulfide, carboxylic acids, 4-methylphenol, aldehydes, indole, and skatole) except trimethylamine. The method was applied in situ at two full-scale filters installed at swine houses. The results have been compared with analyses by thermal desorption gas chromatography-mass spectrometry (TD-GC/MS), and odor was measured by olfactometry. By comparison with TD-GC/MS, observed MIMS signals were assigned to 4-methylphenol, 4-ethylphenol, indole, skatole, the sum of volatile reduced organic sulfur compounds (ROS), and three subgroups of carboxylic acids. The removal rates were observed to be related to air-water partitioning with removal efficiencies in the range of 0 to 50% for low-soluble organic sulfur compounds and high removal efficiencies (typically 80-100%) for more soluble phenols and carboxylic acids. Based on the results and published odor threshold values, it is estimated that the low removal efficiency of ROS is the main limitation for achieving a higher odor reduction.
生物空气过滤器已被提议作为一种具有成本效益的技术，用于减少集约化养猪场的恶臭排放。在这项工作中，我们展示了膜进样质谱（MIMS）在连续监测生物空气过滤器中恶臭化合物去除方面的应用结果。在选定的恶臭化合物的合成样品上测试了灵敏度和选择性，并证明了所有测试化合物（甲硫醇、二甲基硫、羧酸、4-甲基苯酚、醛、吲哚和粪臭素）都具有线性和较低的 ppb 范围的检测限（除三甲胺外）。该方法应用于两个安装在猪舍中的全尺寸过滤器中。结果与热解吸气相色谱-质谱（TD-GC/MS）分析进行了比较，并通过嗅探法测量了气味。通过与 TD-GC/MS 的比较，观察到的 MIMS 信号被分配给 4-甲基苯酚、4-乙基苯酚、吲哚、粪臭素、挥发性还原有机硫化合物（ROS）的总和以及羧酸的三个亚组。去除率与气-水分配有关，对于低水溶性有机硫化合物，去除效率在 0 到 50%之间，对于更易溶解的酚类和羧酸，去除效率通常为 80-100%。根据结果和已发表的气味阈值值，估计 ROS 的低去除效率是实现更高的气味减少的主要限制。
