【作者】 刘强；

【导师】 马广大；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2003， 博士

【摘要】 挥发性有机化合物(VOCs)是仅次于颗粒污染物的又一大类气态污染物。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废气是近年来发展起来的工艺，与传统净化工艺相比，具有设备简单、投资少、运行费用低、无二次污染等优点，因而受到学者的重视。 本文分别以活性炭、拉西环作为填料，考察了混合菌滴滤塔对含苯废气、含二甲苯废气的净化效果；然后又以两种陶粒为填料，以筛选出的二甲苯降解菌——坚硬芽孢杆菌对滤塔挂膜，考察滤塔的净化效果，并研究了喷淋液流量、喷淋液中氮源的浓度等因素对净化效果的影响，对净化过程的动力学进行了分析，并用试验数据进行了验证。最后，通过将坚硬芽孢杆菌包埋后制成的固定化颗粒作为滤塔的填料，考察了滤塔对含二甲苯废气的净化效果。 混合菌生物滴滤塔净化含苯废气的研究结果表明：滤塔填料的体积去除负荷随体积负荷的增加而增加，但二者并非线性关系；气体停留时间越短，滤塔的净化效率越低；活性炭滤塔的净化效率较高，但压降要远高于拉西环滤塔的压降。 混合菌生物滴滤塔净化含二甲苯废气的研究结果表明：以拉西环为填料的滤塔的净化效果较差，而且数据波动较大。 高效生物滴滤塔净化含二甲苯废气的研究结果表明：采用纯种细菌可以显著提高滤塔的净化效果。在气体停留时间为84.8和28.3s，入口二甲苯浓度一定时，随着喷淋液流量的增加，滤塔的净化效果降低；在气体停留时间为17.0s时，喷淋液流量变化对滤塔的净化效果无显著影响。气体停留时间为84.8s和28.3s时，在本试验的范围内(浓度≤3000mg／m~3)，两座滤塔均能保持较高的净化效率(≥97％)；当气体停留时间为17.0s时，随着入口中二甲苯浓度的增加，净化效率逐渐降低。对于滤塔1，当入口浓度增加到3000mg／m~3时，净化效率下降到80％左右；对于滤塔2，当入口浓度增加到3000mg／m~3时，净化效率下降到82％左右。增加喷淋液中氮源的浓度可以提高滤塔的净化效果；以氨氮作为氮源容易造成硝化细菌在滤塔中的累积，影响去除效果。随着滤塔的运行，填料层的压降逐渐升高，因此，应当采 西安建筑科技大学博士学位论文一取措施控制生物膜的厚度。滤塔各单元填料层单位质量填料的可挥发性生物膜干重的测量结果表明，生物在滤塔高度方向不均匀。对比两种填料可以发现，2＃陶粒无论是挂膜性能、净化效率，还是抗冲击负荷能力，都是优于1＃陶粒，尽管2＃陶粒的压降是1＃陶粒的2倍左右，但尚在可以接受的范围之内。 动力学分析表明生物降解一级反应动力学模型能较好地与实验数据吻合，常数f·a／Q随入口浓度 C。；的增大而升高。 对于优势菌种生物滴滤塔（两种陶粒为填料）净化工甲苯废气的过程，个。／Q F。（C＿。＼＿＿＿．与C。；的关系为 y＝5689．4exP15ful 适用范围为C。；＜4500mg／m＼ ’g‘””””””O“t 2453．5）“” 对于混合菌群生物滴滤塔（大拉西环为填料）净化二甲苯废气的过程，个a心 F。（C＿。＼＿＿．＿与 C。，的关系为 y－12980．3exPI SLI 适用范围为 C。；＄3500 mg／m飞 一g’—”—”O“［1651．3）“” 对于混合菌群生物滴滤塔H拉西环为填料）净化二甲苯废气的过程，f·。／Q f．＿（C＿：＼＿＿＿与C。；的关系为y＝18379．oexpl二千三1 适用范围为C。＜3200m咖。 －g’”－”O“＼1564．5）”‘一 固定化生物滴滤塔净化二甲苯废气的研究结果表明：固定化生物颗粒滤塔对二甲苯废气有相当的净化能力，但比陶粒滤塔的净化效果差。固定化颗粒的制作条件对于净化效果及颗粒的使用寿命有很大影响；颗粒包埋的菌体量多，则滤塔的净化效果较好；颗粒的活化可以提高滤塔的净化效果；增加钙化时间可以提高固定化颗粒的强度和使用寿命。 本研究表明，通过人工筛选菌种进行VOCS废气净化，在技术上是可行的，并能有效提高空塔气速，减小设备尺寸，这为该技术的最终应用指明了研究方向更多还原

【Abstract】 Volatile Organic Compounds (VOCs) is another kind of contamination junior to particles. They do great harm to human health and cause heavy pollution, however, are hard to control, especially for waste gases borne with low-concentration VOCs. So, an effective control approach is urgent. Biotreatment of air-borne contaminants offer an alternative to conventional air treatment technologies. Because of its advantages, such as simple equipment, low investments & operational spending and no secondary-pollution, it has received increased attention of scholars around the world.Two biofilters packed respectively with the activated carbon and rasching rings, inoculated with the activated sludge, which was domesticated by contamination, were used to purify the waste gases contained benzene and xylene vapor individually. And then another two kinds of ceramic pellets were filled into the filters and inoculated withxylene biodegraded bacteria-Bacillus firmus, which was screening by incubatorshaker experiment. The purifying performances of reactors were investigated. Moreover, the trickling flux and the N concentration in the trickling liquid’s effects on biofilters’ performance were thoroughly examined. Finally, the purifying efficiency of reactor packed with grains, in which the Bacillus firmus were immobilized, was examined.The results of trickling biofiltration experiments purging benzene vapor show that volume removal loadings of biofilters are increased along with the volume loadings, but the relationship between them are non-linear. The lower EBCT (empty bed contract time) is, the worse the reactors’ performance is. The filter packed with activated carbon gain a better performance compared with the one packed with rasching rings, but the former own a much higher pressure drop when the fluid passes through it.The results of trickling biofiltration experiments purging xylene vapor show that the filters packed with rasching rings have low removal efficiency, and the performance of reactors are highly fluctuant.The results of high-effective trickling biofiltration experiments purging xylene vapor show that the biofilters inoculated with Bacillus firmus can get increased removal efficiency. For certain inlet concentration, when the EBAT (empty bed attained time) were 84.8s and 28.3s, the removal efficiency decreased along with the increase of drenching density of nutrient liquid. When the EBAT reduced to 17.0s, the drenching density of nutrient liquid had no significant effect on the performance of biofilters. At the EBAT of 84.8s and 28.3s, the biofilters can maintenance the removal efficiency no less than 97% when the inlet concentration was no more than 3000mg/m3. But, at the EBAT of 17.0s, the performance of biofilters deteriorated as the inlet concentration increased. For the biofilter 1 and 2, a removal efficiency of 80% and 82% can respectively be obtained when the inlet concentration was up to 3000mg/m3. Results show that higher removal efficiency can be obtained when the concentration of N in the nutrient liquid was increased. And, usage of NH4-N as the N source can cause the notified bacterium’s accumulation in the biofliters. The pressure drop of the biofliters will be higher and higher because of the bacterium ’s propagation, so some efforts should be made to control the biofilm’s thickness. The measure results of biofilm’s volatile suspended solid in the filters’ unit show an uneven distribution of biofilm along the height in the biofilters. Compare with the 1# ceramic pellet, the 2# ceramic pellet owned a better inoculation and anti-impulse loadings ability, moreover, higher removal efficiency. Although the pressure drop of filter packed with 2# ceramic pellet are as twice as that packed with 1# ceramic pellet, there are low enough to be accepted.The results of Dynamic analysis show that one-stage biodegradation kinetic model coincide with experiment results well. And, the constant /Q changed along with the inlet concentration Cgi.For the biofilters inoculated with Bacillus firmus and were更多还原