【作者】 吴丹；

【导师】 全燮；

【作者基本信息】 大连理工大学 ， 环境工程， 2007， 博士

【摘要】 生物过滤法由于其具有低成本、操作简单、无二次污染等优点，已被认为是富有前景的处理低浓度可生物降解的恶臭和挥发性有机物（VOCs）的废气处理技术。然而在生物过滤器长期运行处理VOCs废气，特别是高污染负荷VOCs混合废气时，混合气组分间存在的抑制影响以及填料中的氮营养物质的缺乏往往成为VOCs生物降解的限制因素。本研究对生物过滤反应器长期处理高浓度的具有不同生物可降解性VOCs与NH₃三组分混合废气的去除效果进行了研究，以及探索解决生物过滤反应器长期处理混合废气过程中营养缺乏问题的简便而有效的方法。本研究采用堆肥和聚乙烯（PE）为填料的生物过滤反应器处理高浓度乙酸丁酯、对二甲苯和NH₃的混合废气。考察了在不同浓度、不同空床停留时间条件下生物过滤反应器对乙酸丁酯、对二甲苯和NH₃的处理效果；描述了生物降解过程中污染物组分间的抑制作用；探索并确立了NH₃作为生物过滤反应器去除此混合气时微生物所需的氮营养物质的可行性；考察了不同NH₃浓度对生物过滤反应器处理乙酸丁酯、对二甲苯和NH₃混合气处理效果的影响，确立了适宜的NH₃浓度范围；并对生物过滤反应器运行过程中填料中的、pH、湿度以及微生物状态变化进行了考察。本研究还考察了采用由填有堆肥和PE混合物的堆肥生物过滤器和填有挂有生物膜的PE生物过滤器所组成的复合生物过滤器对高浓度对二甲苯废气的去除效果。本研究的主要结论为：（1）采用由堆肥生物过滤反应器和PE生物过滤反应器组成复合生物过滤反应器可以成功地去除高浓度的对二甲苯废气。在对二甲苯的入口浓度为100-3300 mg·m^-3，EBRT为132s时，去除率在80％以上，可获得80g·m^-3·h^-1的去除负荷。EBRT为30s时，反二甲苯的最大去除负荷为40g·m^-3·h^-1。（2）乙酸丁酯、对二甲苯和NH₃混合废气可以在以堆肥和PE为主要填料的三段式生物过滤反应器中有效地去除。当EBRT为60s和30s时，得到的高的乙酸丁酯去除负荷为157g·m^-3·h^-1和150g·m^-3·h^-1，相应地去除率约为100％和96％。乙酸丁酯的去除主要发生在反应器第一段。当在总EBRT为60s（即第一段EBRT为20s），乙酸丁酯入口负荷为471g·m^-3·h^-1时，乙酸丁酯在第一段的去除负荷为397g·m^-3·h^-1。在EBRT为30-90s，对二甲苯入口浓度为45-827 mg·m^-3时，去除率为40-100％。对二甲苯在EBRT为60s时的最大去除负荷为33g·m^-3·h^-1。在EBRT为60s和30s时，达到100％去除时的对二甲苯的去除负荷分别为30g·m^-3·h^-1和24g·m^-3·h^-1。NH₃在EBRT为60s和30s，入口浓度为43-150 mg·m^-3时的去除率近100％。（3）在乙酸丁酯和对二甲苯共存的条件下，生物过滤反应器优先去除乙酸丁酯。较高浓度的乙酸丁酯的存在会抑制生物过滤反应器中对二甲苯的去除。（4） NH₃既可以作为污染物被去除，同时也可以作为微生物所需的氮营养物质为生物过滤反应器去除混合废气提供氮营养。在三段式生物过滤反应器中，对于由于NH₃引入，使对二甲苯在EBRT为60s时的去除率为100％的最大去除浓度(510 mg·m^-3)高于EBRT为90 s时的去除率为100％的最大去除浓度(400 mg·m^-3)。（5）不同的NH₃入口浓度对生物过滤反应器处理混合气的处理效果有很大的影响。在单段的填有堆肥和PE混合填料的生物过滤器中，保持EBRT （EBRT=60 s）恒定时，在一定的NH₃入口浓度(13-193 mg·m^-3)范围内，NH₃的存在改善了乙酸丁酯和对二甲苯的生物过滤处理效果，并随着NH₃入口浓度的提高，乙酸丁酯和对二甲苯的去除负荷增加。但当NH₃浓度过高(211-493 mg·m^-3)时，对混合气的去除负荷并未随着NH₃浓度的增加而明显增加，而是与低NH₃浓度(13-80 mg·m^-3)下的混合气去除负荷相接近。在此堆肥生物过滤反应器中和操作条件下，适宜的NH₃入口浓度为145～193 mg·m^-3。（6）对二甲苯的去除对NH₃浓度变化比较敏感。（7）连续运行的处理乙酸丁酯、对二甲苯和NH₃混合气的生物过滤反应器中，填料的pH、湿度和氮含量均发生变化。NH3的引入对填料的pH和氮含量存在影响。在生物过滤反应器运行过程中，填料无酸化现象发生，填料中的氮含量在没有NH₃引入时逐渐减少。当NH₃引入后，氮含量增加。反应器的填料中细菌和真菌数增加，特别是在接近污染气体入口处，这是由于在接近反应器的入口处高的污染负荷。总之，填有堆肥和PE混合填料的生物过滤器可以成功地去除高浓度乙酸丁酯、对二甲苯和NH₃混合气。NH₃可以作为生物过滤反应器处理乙酸丁酯、对二甲苯和NH₃混合气时微生物的氮营养物质。更多还原

【Abstract】 Biofiltration has been recognized as a cost-effective and promising technology for the purification of air streams contaminated with low concentrations of biologically degradable volatile organic compounds （VOCs） because of low costs, operational simplicity and limited negative environmental effects. However, during the long-term operation of biofilters, especially with high VOCs load, available nutrient deficiency and inhibition of VOCs components may be limiting factors for degrading VOCs when VOCs mixtures are removed in biofilters. The major objectives of this work were to investigate the biofiltration of the mixtures of different biologically degradable VOCs and NH₃ with high inlet concentrations, and to resolve the nutrient deficiency for degrading VOCs during the long-term operation of biofilters and seek a convenient and effective method of nutrient addition.In this work, the biofilters packed with the mixtures of compost and polyethylene （PE） were employed to remove the mixtures of n-butyl acetate, p-xylene and NH₃ with high inlet concentrations. The removal efficiencies of n-butyl acetate, p-xylene and NH₃ were investigated with various concentrations at various empty bed residence time （EBRT）. The inhibition effect of VOCs components was described. The availability of NH₃ as the nutrient for microorganisms degrading n-butyl acetate and p-xylene was determined. Furthermore, an optimal concentration of NH₃ was obtained by investigating the removal of the mixtures of n-butyl acetate, p-xylene and NH₃ with various NH₃ concentrations in biofilters packed with the mixtures of compost and PE. The nutrients, pH, water content and microbial characteristics in packing media were measured. In addition, the removal of p-xylene with high inlet concentrations was performed in a hybrid biofilter which consisted of a compost-based biofilter and a biofilter packed with PE.The following main conclusions were obtained:（1） p-Xylene was successfully removed in a hybrid biofilter which consisted of a compost-based biofilter and a biofilter packed with PE. At EBRT of 132 s, the removal efficiency was more than 80% and the elimination capacity of 80 g·m^-3·h^-1was obtained with the inlet concentrations of 100-3300 mg·m^-3. At EBRT of 30 s, the maximum elimination capacity was 40 g·m^-3·h^-1.（2） The mixtures of n-butyl acetate, p-xylene and NH₃ could be effectively eliminated in a three-section biofilter packed with the mixtures of compost and PE. At EBRT of 60 s and 30 s, high elimination capacities of 157 g·m^-3·h^-1 and 150 g·m^-3·h^-1 were obtained corresponding to the removal efficiencies of 100% and 96% respectively. When the inlet load of n-butyl acetate was 471 g·m^-3·h^-1, the elimination capacity was 397 g·m^-3·h^-1 in the 1st section of the biofilter at total EBRT of 60 s corresponding to EBRT of 20 s for 1st section of biofilter.At EBRT of 30-90 s, the removal efficiencies of p-xylene were 40-100% with inlet concentrations of 45-827 mg·m^-3. The maximum elimination capacity of p-xylene was 33 g·m^-3·h^-1 at EBRT of 60 s. With the removal efficiency of 100%, the elimination capacities were 30 g·m^-3·h^-1 and 24 g·m^-3·h^-1 at EBRT of 60 s and 30 s respectively. At EBRT of 60 s and 30 s, the removal efficiency of NH₃ was approximate 100% with inlet concentration of 43-150 mg·m^-3.（3） At the simultaneous presence of n-butyl acetate and p-xylene, the removal of n-butyl acetate was more available than that of p-xylene, and the removal ofp-xylene was inhibited by the presence of high concentration of n-butyl acetate.（4） NH₃ was not only removed as a pollutant, but also added as the nitrogen nutrient for degrading VOCs by microorganisms.In the three-section biofilter, due to the feeding of NH₃, the maximal removal concentration of p-xylene with the removal efficiency of 100% was 510 mg·m^-3 at EBRT of 60 s, which wasmore than 400 mg·m^-3 at EBRT of 90 s.（5） The removal of the mixtures of n-butyl acetate, p-xylene and NH₃ was remarkably affected by the variation of NH₃ inlet concentration in biofilters packed with the mixtures of compost and PE. At constant EBRT of 60 s, with the range of NH₃ inlet concentration of 13-193 mg·m^-3, the presence of NH₃ improved the removal of n-butyl acetate and p-xylene, and the elimination capacities of n-butyl acetate and p-xylene increased with the increase of NH₃ inlet concentration. However, when the inlet concentration of NH₃ was in the range of 211-493 mg·m^-3, the elimination capacities of n-butyl acetate and p-xylene did not keep increasing with the increasing of NH₃ inlet concentration and were similar to those obtained with NH₃ inlet concentration of 13-80 mg·m^-3. An optimal inlet concentration of NH₃ was 145-193 mg·m^-3 for good performance of the biofilter under these operation conditions in this biofilter.（6） The removal of p-xylene was sensitive to the variation of NH₃ inlet concentration.（7） pH, water content and nitrogen content of packing media changed in the biofilters where the mixtures of n-butyl acetate, （?）-xylene and NH₃ were continuously removed. The feeding of NH₃ affected pH and nitrogen content of packing media. No acidification occurred in the packing media in during the operation of biofilters. Nitrogen content of packing media gradually decreased without the feeding of NH₃, and after the feeding of NH₃, the nitrogen content of packing media increased.The bacteria and fungi colony counts in packing media increased during the operation period, especially at the inlet section of the biofilter which was due to the high contaminants load at the inlet section of the biofilter.In conclusion, the mixtures of n-butyl acetate, p-xylene and NH₃ with high inlet concentrations were successfully eliminated in a biofilter packed with the mixtures of compost and PE. NH₃ could be used as nitrogen nutrient for degrading the mixture of n-butyl acetate, p-xylene and NH₃ in the biofilter.更多还原