【作者】 陈波；

【导师】 张耀斌；

【作者基本信息】 大连理工大学 ， 环境工程， 2009， 硕士

【摘要】 挥发性有机化合物（VOCs）是仅次于颗粒污染物的一大类大气污染物。对于低浓度VOCs废气的控制较难。寻求合理的治理途径和控制方案已成为世界各国亟待解决的热点课题。生物法净化VOCs废气具有设备简单、投资少、运行费用低、无二次污染等优点,其中生物滴滤法由于其运行参数易于控制等优点更是成为研究的热点。苯乙烯一种典型的单环芳香类VOCs,对人体和环境具有较大的危害性,同时苯乙烯较难溶于水,适于生物滴滤法去除。因此,本实验选择苯乙烯作为目标物,选取改性聚乙烯环为填料,通过快速排泥挂膜法进行微生物的接种驯化,综合考察空床停留时间、气体浓度、循环液营养和循环液pH对生物滴滤法处理苯乙烯性能的影响,并考察了床层压降和矿化率的变化。研究结果表明,1.通过快速排泥法挂膜,反应器可在较短周期内实现微生物的驯化,并表现出良好的处理能力。苯乙烯浓度和空床停留时间是影响反应器性能的重要因素,当空床停留时间分别为60 s、45 s、30 s和15 s时,对应的入口浓度分别为1400 mg·m^-3、430 mg·m^-3、350mg·m^-3和200 mg·m^-3时,对应的去除负荷为82 g·m^-3·h^-1、31.2 g·m^-3·h^-1、35.6 g·m^-3·h^-1和40.8 g·m^-3·h^-1,可实现达标排放,此时填料床层对苯乙烯的去除能力是:上段>中段>下段。随着空床停留时间的缩短,床层压降的增加与空塔气速的提高成线性关系。2.循环喷淋液中的硝酸盐（亚硝酸盐）对生物滴滤池的影响十分明显,在初始阶段,亚硝酸根很快被耗尽,硝酸根则相对缓慢。当循环液中的TN浓度从532.3 mg·L^-1下降到102.6mg·L^-1时,苯乙烯的去除效率在92%-99%之间波动,苯乙烯废气的入口浓度维持在500mg·m^-3,滴滤塔的总去除能力在46.0 g·m^-3·h^-1上下波动:当TN从102mg·L ^-1下降到24mg·L^-1,滴滤池的去除效率由94%下降到43%,苯乙烯废气的进样浓度从500mg·L^-1下降到了220 mg·L^-1,滴滤床的总去除负荷也从45.1 g·m^-3·h^-1下降到了22.3g·m^-3·h^-1。部分原因是NO_x^-浓度降低导致反硝化作用减弱,减小碳源的反硝化利用,同时被循环液的pH上升所证明。在这个过程中,生物滴滤塔高负荷运行时的矿化率明显低于低负荷运行时的矿化率。更多还原

【Abstract】 Volatile organic compounds （VOCs） are major organic pollutants which are only fewer than the particle pollutant. VOCs are difficult to be removed at low concentration specially, and which has been become the hot subjects at all over the world. Biological method is very promising due to many advantages, such as simple devices, less investments, lower operation cost and no second pollutions. Biotrickling filter has been focused on more interesting because of the simple operation parameters.Styrene is one of the typical aromatic organic compounds, which has seriously harmful to the human body and the nature environment. On the other hand, styrene is hydrophobic, and it is suitable to be removed by the biological methods. Therefore, styrene is chosen as the target object in this experiment. The modified PE is selected as padding and the method of rapid sludge discharging is employed to inoculate and domesticate the biomass. The influences of empty bed residence time （EBRT） of filter, styrene concentration, the nutrition and the pH value of the circulation solution on the removal of styrene in biotrickling filter have been investigated. Furthermore, the pressure drop and the the mineral ratio of the filter are also considered. The results are shown as following:1. In the biofilters, the biomass could be domesticated using the method of rapid sludge discharging in a short period, and the biofiiters exhibited the high ability of VOCs removal. Concentration of styrene and EBRT had important influences on the performance of the reactor. The elimination capacities were 82 g.m^-3.h^-1, 31.2 g.m^-3.h^-1, 35.6 g.m^-3.h^-1 and 40.8 g.m^-3.h^-1 at EBRT of 60 s, 45 s, 30 s and 15 s with the inlet concentrations of 1400 mg·m^-3, 430 mg·m^-3, 350 mg·m^-3 and 200 mg·m^-3, respectively. The effluence of the reactor could achieve the national discharge standard. At the same time, the elimination capacity of the three stages filter is the order: the upper bed > the second bed > the lower bed. When the empty tower gas velocity was shorten, the pressure drop increased largely with shortening the empty tower gas velocity in line.2. The effect of the nitrite and nitrate in the sprayer circulation solution on the ability of the biotrickling filter was very clearly. At the starting times, nitrite would exhaust quickly and the nitrate would exhaust much slowly. When the TN concentration of circulation solution dropped from 532.7 mg·L^-1 to 102.63 mg·L^-1 and the styrene inlet concentration kept 500 mg.m^-3, the removal efficiencies were fluctuating between 92%-99%, and the total elimination capacities were fluctuating between 46.0 g.m^-3.h^-1 more or less. When the TN concentration of the circulation solution dropped from 102.63 mg·L^-1 to 24.24 mg·L^-1, the removal efficiencies dropped from 94% to 43%, the styrene inlet concentration dropped from 500 mg.m^-3to 220 mg.m^-3 else, the total elimination capacities of the biotrickling filter decreased from 45.1 mg·L^-1to 22.3 mg·L^-1. The reason could be that the capacity to use carbon resource decrease due to the lack of NO_x^-, which could be supported by the fact of the increase of pH in the solution treated. In this process, the mineral ratio of the biotrickling filter at large inlet styrene capacity was much lower than that of the low inlet styrene capacity.更多还原