水力负荷对硫自养反硝化处理微污染水的影响

发布时间：2018-10-26 12:16

【摘要】：近年来我国环境问题日益突出,尤其是南方广大湖泊水体的富营养化污染问题,其中氮污染主要体现为NO3--N超标问题。传统的反硝化工艺因需要投加大量碳源,在该类水的生物脱氮方面存在局限性,故开发和发展新型生物脱氮技术迫在眉睫。硫自养反硝化技术因其不需外加碳源、无二次污染、污泥产量少、运行成本低等特点,成为处理该类水体的首选工艺之一,但目前该工艺的研究尚处于起步阶段。本论文采用硫代硫酸盐为电子供体的硫自养反硝化技术,并结合生物滤池系统,对微污染水体中NO3--N进行脱氮处理,以期研究成果为实际工程提供技术参考。论文以脱除NO3--N为目标,主要研究了水力负荷对生物滤池脱氮效果的影响,探索了生物滤池的外形尺寸设计参数,为硫自养反硝化生物滤池的设计和运行提供了理论依据,通过多组对照实验,得出以下结论:采用厌氧污泥作为硫自养反硝化菌的接种污泥,驯化时间短,而采用剩余活性污泥作为硫自养反硝化菌的驯化污泥,系统中存在NH4+-N释放问题,TN浓度逐渐升高无降低趋势,驯化时间较长。以两种常见的陶粒作为反应器的填料,在相同条件下连续运行,两个反应器出水水质基本一致,表明陶粒粒径对硫自养反硝化系统影响较小。实验研究了高径比为5.7和16.1的两个相同体积的反应器分别所能达到的最短HRT和最大水力负荷,结果发现,在水力负荷小于1.0m3/(m2·h)的运行条件下,小高径比的反应器比大高径比的反应器脱氮效果稳定,而当水力负荷大于1.0m3/(m2·h)时,大高径比的反应器比小高径比的反应器处理能力高、脱氮效果好;小高径比的反应器最短HRT、最大水力负荷分别为0.5h、1.0m3/(m2·h),且在此运行条件下反应器TN和NO3--N的平均去除率分别为83%和89%,而大高径比的反应器在最短HRT和最高水力负荷达到10min和6.0m3/(m2·h)时,TN、NO3--N的平均去除率仍能维持在89%、94%左右;两个反应器稳定运行后,出水均未出现NO2--N的积累现象。对反应器中的陶粒和污泥进行SEM观察,发现各反应器中的微生物均呈长丝状,主要在污泥中成团生长,只有极少量的微生物富集在陶粒表面。对反应器不同阶段污泥中的微生物进行分子生物学分析,结果显示,反应器中微生物物种分布各异。除了人们已经发现的硫杆菌属(Thiobacillus),实验还发现了多个微生物种属能够参与硫自养反硝化过程,但Thiobacillus在系统中占较高比例,为8.4%,对硫自养反硝化反应起主要作用;系统中各功能菌属的所适宜的生存条件不同,Thiobacillus适于在较高NO3--N浓度和较为稳定的环境条件下生长,而丝硫菌属(Thiothrix)与硫微螺菌属(Sulfurimonas)可以在氮浓度更低和水流更急的条件下存活。
[Abstract]:In recent years, environmental problems in China have become increasingly prominent, especially the eutrophication pollution of the vast number of lakes in southern China, in which nitrogen pollution is mainly reflected in the problem of NO3--N exceeding the standard. Because the traditional denitrification process needs a large amount of carbon source, there are some limitations in the biological denitrification of this kind of water, so it is urgent to develop and develop a new biological denitrification technology. The technology of sulfur autotrophic denitrification has become one of the preferred processes for treating this kind of water because of its characteristics of no additional carbon source, no secondary pollution, less sludge production and low operating cost. However, the research of this process is still in its infancy. In this paper, sulfur autotrophic denitrification technology with thiosulfate as electron donor and biological filter system were used to treat NO3--N in micro-polluted water, in order to provide technical reference for practical engineering. In order to remove NO3--N, the effect of hydraulic load on denitrification of biofilter was studied in this paper. The design parameters of shape and dimension of biofilter were explored, which provided a theoretical basis for the design and operation of sulfur autotrophic and denitrifying biofilter. The following conclusions are drawn from the multi-group controlled experiments: the acclimation time is short when the anaerobic sludge is used as the inoculation sludge of the sulfur autotrophic denitrifying bacteria, while the surplus activated sludge is used as the acclimation sludge of the sulfur autotrophic denitrifying bacteria. There is a problem of NH4-N release in the system. The concentration of TN increases gradually and does not decrease, and the domestication time is longer. Under the same conditions, the effluent quality of the two reactors was basically the same, which indicated that the diameter of the ceramsite had little effect on the autotrophic sulfur denitrification system. The shortest HRT and maximum hydraulic load of two same volume reactors with ratio of height to diameter of 5.7 and 16.1 are studied experimentally. The results show that the hydraulic load is less than 1.0m3/ (m 2 h) when the hydraulic load is less than 1.0m3/ (m 2 h). The denitrification efficiency of the reactor with small ratio of height to diameter is more stable than that of the reactor with large ratio of height to diameter. When the hydraulic load is greater than 1.0m3/ (m ~ 2 h), the treatment capacity of the reactor with large ratio of height to diameter is higher than that of the reactor with small ratio of height to diameter, and the effect of denitrification is better. The shortest HRT, maximum hydraulic load of the reactor with small aspect ratio is 0.5 h ~ (-1) 1.0 m ~ (3) / (m ~ (2) h), and the average removal rates of TN and NO3--N are 83% and 89%, respectively. The average removal rate of TN,NO3--N in the reactor with high aspect ratio is about 89% when the shortest HRT and maximum hydraulic load are 10min and 6.0m3/ (m 2 h). After stable operation of the two reactors, there was no accumulation of NO2--N in the effluent. By SEM observation of ceramsite and sludge in the reactor, it was found that the microbes in each reactor were long filamentous, mainly grew in the sludge, and only a very small number of microbes were concentrated on the surface of the ceramsite. The results of molecular biological analysis of microorganisms in sludge at different stages of the reactor showed that the distribution of microbial species in the reactor was different. In addition to the (Thiobacillus), experiments of Thiobacillus, many microbes were found to be able to participate in the process of sulfur autotrophic denitrification, but Thiobacillus played a major role in the autotrophic denitrification of sulfur, accounting for a high proportion of 8.4% of the total amount of thiobacterium, which played a major role in the reaction of sulfur autotrophic denitrification. The suitable living conditions of each functional genus in the system are different, and Thiobacillus is suitable for growth under higher NO3--N concentration and more stable environmental conditions. (Thiothrix) and (Sulfurimonas) could survive under the condition of lower nitrogen concentration and faster water flow.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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