【作者】 李慧颖；

【导师】 黄少斌；

【作者基本信息】 华南理工大学 ， 环境工程， 2010， 硕士

【摘要】 氮氧化物(NOx)是造成大气污染的主要污染源之一,大量排放给自然环境和人类生产及生活带来严重的危害。传统的NOx治理方法复杂、难度大、费用昂贵,世界各国都在努力寻找和研究NOx的控制和治理新方法。本文通过优化优势的好氧反硝化菌系及其培养条件,建立生物滤塔,研究了有氧条件下用生物滤塔反硝化去除NOx的效能,探讨了NOx在塔中的生化转化机制以及非稳态情况下生物滤塔的恢复效果。对去除过程的动力学进行了分析,并用实验数据进行了验证。研究旨在为生物滤塔的工业化应用在设计、运行过程等方面提供理论基础。利用正交实验方法对好氧反硝化菌系的培养条件进行优化,将筛选出的好氧反硝化菌系(好氧反硝化菌种A1、A2、A3混合制成)接种于生物滤塔,研究了好氧条件下生物滴滤塔反硝化去除NOx的效果。结果表明,该系统能有效克服氧对反硝化菌活性的抑制作用,实现了对NOx的高效脱除。在O2体积分数为10%、NOx进气浓度为286.4 mg/m3、EBRT为59s时,NOx净化效率能够达到93.6%。在生物滤塔系统中存在以兼性反硝化菌为主,多种菌种共存的微生物混合体系。通过对生物滤塔的抗NOx冲击负荷能力的研究,结果表明,当NOx进气浓度由352.3mg/m3突然提高至754.9 mg/m3时并不能使系统崩溃,反应器仍可以恢复处理能力。生物滤塔在停运2 d、5d后只需12h、42h即可以恢复对NOx的去除能力,去除效率达到停运前水平。而在停止供水供气的情况下10d,塔内的微生物全部失活,若在停运时间歇供气供水,塔的净化效果可以恢复。针对生物滤塔的堵塞等现象,采用气水联合冲洗的方式进行反冲洗,研究了反冲洗的周期及冲洗后滤塔的恢复能力。反冲洗周期为10-15天,反冲洗后滤塔需要约60小时左右才能恢复正常的脱硝能力,NOx去除率可达到86.9%。通过“吸附-生物膜”理论对生物滤塔的去除能力进行了探讨,根据其动力学模型计算了生物滤塔对NOx的生化去除量和NOx出口浓度,发现模型计算值与实验值之间相关性较好,说明“吸附-生物膜”理论模型描述生物滴滤塔对低浓度NOx废气的净化过程能够得到比较准确合理的结果,可为相关的理论研究和实际操作提供指导和帮助。更多还原

【Abstract】 Nitrogen oxides (NOx) are one of the major sources caused air pollution, its emissions will bring serious harm to natural and life and production of human. Conventional NOx treatment technologies are difficult, complex and expensive. People in the world are making efforts to look for and investigate new ways to control NOx pollution.Optimized aerobic denitrifiers were applied to a biofilter for the removal of NOx. The removal process of NOx was investigated,and the biochemical conversion mechanism under aerobic conditions are discussed. Achieve the operation data of biological trickling filter under non-steady-state by changing the operating conditions. Kinetics of the NO removal were analyzed and validated with experimental data. This paper is rearched in the in the design, and operation of biotrickling filter to provide theoretical basis for industrial application.The medium components and culturing conditions were optimized for the better aerobic denitrifiers system by using sophisticated orthogonal method. The biofilter finished start-up after 26 days and the presence of oxygen has no evident negative effect on the efficiency of NOx removal. The biofiltration system could remove NOx at high efficiency of 93.6% at the EBRT of 58s and the inlet NOx concentration of 286.4 mg/m3 with 10% O2. The removal process consisted of chemical oxidation and bio-nitrification in the biofilter. The bioprocess mainly contributed to the removal. Exist in the biological filtration system to facultative denitrifying bacteria, many strains of microorganisms coexist mixed system.Obtain operation data of biotrickling filter in case of non-steady state by changing the operating conditions. Results showed that the biofilter has strong buffering capacity when the inlet NOx concentration changed, when the inlet NOx concentration suddenly increased from 352.3mg/m3 to 754.9 mg/m3 didn’t lead the system crash, the treatment capacity of reactor can be recovered if adjust the NOx concentration in time. Biofilter after 2d and 5d outage, the NOx removal ability can be restored with the restart time of 12h and 42h. Complete cessation of water supply in case of outages 10d, all of the microorganisms of the tower are inactive, if supply gas and water during the outage period, the purification effect of biofilter can be restored.The biofilm plugged up the biofilter after running for some time, so this study uses gas-water backwash method to wash the biofilter. The optimum backwash cycle and the ability to recover of the biofilter after backwash were studied. Backwash cycle is 10-15 days. After backwashing biofillter will take some time (about 60 hours or so) to restore normal denitrification capacity.According to the kinetic calculation models,the NOx biological elimination and the NO outlet concentration were calculated to the change of inlet concentration. The calculated data show that the kinetic model constructed based on the“absorption-biofilm”theory was valuably applied to the NO removal process of the biofilter, and could offer guidance and help for the relative theory or practical operation.更多还原