【作者】 余关龙；

【导师】 杨春平；

【作者基本信息】 湖南大学 ， 环境工程， 2008， 硕士

【摘要】 近年来,从大规模工业生产或化学药剂制造过程中排放的大量的挥发性有机物(volatile organic compounds, VOCs),不但污染环境,还危害人体健康。采用生物法处理低浓度VOCs发展迅速。其中生物滴滤技术被认为是高效、经济和环境友好的控制技术,并且不会产生二次污染。由于合成填料比自然填料具有更多的优点,聚氨酯海绵(25 PPI)作为填料已经在生物滴滤器和转鼓生物过滤器中得到了应用。本研究采用两个相同的实验室规模生物滴滤器装置,以甲苯为模型VOCs,以整块开孔网状聚氨酯海绵材料作为生物滴滤器中微生物依附的载体,分别考察并评价了VOCs负荷和气体停留时间对其性能的影响。对于更好设计和应用聚氨酯海绵作为工业规模生物滴滤器的填料具有重要的实际意义。生物滴滤器对实验室模型甲苯废气处理效果良好。气体停留时间对装置的去除效率和去除能力均有较大的影响。在甲苯平均进口浓度为483 mg/m~3时,生物滴滤器去除效率和去除能力均随气体停留时间的缩短而急剧下降。当停留时间分别为30,15和7.5 s时,去除效率分别99%,65%和50%。平均去除能力分别达到了83,37,22 g toluene/m~3·h。进口甲苯浓度也对装置的性能产生了较大的影响。在气体流量为280 L/h的条件下,对于甲苯气体,去除效率随进口气体浓度升高呈下降的趋势。当进口甲苯浓度低于713 mg/m~3时,去除效率超过99%;继续增加进口甲苯浓度到1130和2710 mg/m~3时,去除效率下降至74%和44%。同样条件下,对甲苯的去除能力的规律均表现为:随进口浓度的升高EC值逐渐变大,升高到一定程度趋势变缓。当有机负荷为分别为85,135,3225 g toluene/m~3·h时,平均去除能力分别达到了845,98,142 g toluene/m~3·h;当进口有机负荷增加到最大值494 g toluene/m~3·h,甲苯去除能力达最大值237 g toluene/m~3·h。以城市污水处理厂的活性污泥混合菌种作为甲苯的降解实验的接种污泥,经驯化以后,不仅对甲苯具有较好的降解性能,而且活性污泥中混合菌群的生物多样性有助于生物滴滤器实现快速启动。实验结果还表明:采用整块网状聚氨酯海绵填料生物滴滤器,当停留时间和进气浓度一定时,生物滴滤器去除甲苯的效率或去除能力,随着填料高度的增加而增加;压力损失随着进口气体流量和甲苯浓度的增加而增加;并且在进口甲苯负荷有较大的波动时,由于分布在填料上的生物膜,能够提供很大的缓冲能力,使其具有很好的抵制冲击负荷的能力。总之,用本生物滴滤器进行甲苯废气的处理,具有填料使用寿命长,易于管理,去除率高,去除能力大等优点,因此,具有广阔的应用前景。更多还原

【Abstract】 Recently, volatile organic compounds (VOCs) present in waste gas streams emitted from large-scale industrial operations or chemicals process were able to result in environment pollution and jeopardize people health. Biological treatment is an emerging rapidly technology for treatment of the low concentration VOCs. In particularly, biofiltration is known as an efficient, economical and environmental friendly technology, and having no second pollutions.Synthetic media have advantages over many natural media, and polyurethane sponges have been applied in biotrickling filters (BTFs) and rotating drum biofilters. In this study, toluene was chosen as the model VOC, open-pore reticulated polyurethane sponges (10 pores per cm) were used as structured packing media in two identical bench-scale BTFs which were separately evaluated at various volatile organic compound loading rates and gas empty bed contact time (EBCT). These investigations are helpful for proper design of full-scale biofilters packed with polyurethane sponges.The BTFs packed with polyurethane sponges have a good performance for treating waste gas containing toluene. Both influent toluene concentration and EBCT have a great effect on performance of BTFs. Toluene removal efficiencies were over 99%, 65% and 50%, and the average elimimation capacity (EC) were 83, 37 and 22 g toluene/m~3·h when the EBCT were 30, 15, and 7.5 s, respectively, at a constant influent toluene concentration of 483 mg/m~3.The influent toluene concentration also influenced the performance of BTFs in a great extend. When the VOC average feed concentration were 713, 1130 and 2710 mg/m~3, correspondingly the organic loading rate of the BTF were 85, 135 and 322 g toluene/m~3·h, the EC increased rapidly to 84 g toluene/m~3·h during the first 15 days, then increased slowly and reached up to 98, 142 g toluene/m~3·h, and removal efficiency were over 99%, 74% and 44% respectively at an EBCT of 30 s.The activated sludge, from municipal wastewater treatment plant, has a good degradation performace for toluene after acclimated by toluene. Effect of inoculation of activated sludge on startup performance of a BTFs after backwashing was also investigated. Result showed that the BTF added activated sludge had a shorter startup period.The results indicated also that the removal efficiency or EC of the BTFs packed with structured polyurethane sponges will enhance with a incresing height of media at a certain infulent toluene concentration and EBCT. The pressure drop will increase with increasing influent gas flow rate and toluene concentration. Moreover, the BTF has a strong capacity of resisting shock loading when the influent organic loading had a wide fluctuation range as the biofilm on the media provide a great buffer capacity.In short, the biotrikling filter is reliabe, highly removal efficient and EC, and easy to be maintained. And meanwhile, the media in the biotrikling filter has a long service life. Therefore, it has a potential application area.更多还原