辽河口滨海湿地芦苇根际土壤中芘和茚并（1,2,3-cd）芘的强化净化技术研究

发布时间：2018-01-04 00:15

本文关键词：辽河口滨海湿地芦苇根际土壤中芘和茚并（1,2,3-cd）芘的强化净化技术研究　出处：《中国海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：辽河口滨海湿地拥有亚洲最大的芦苇湿地,为众多稀有动植物提供栖息地。但由于辽河油田的高强度开发使湿地沉积物和土壤中PAHs的含量较高,其中高分子量(4环-6环)、难生物降解的PAHs就占到总PAHs的近50%,且分布在芦苇的整个生长季内无明显变化。这进一步说明湿地中降解PAHs的微生物活性较低且老化了的PAHs的生物有效性也较低。因此,本文针对辽河口滨海芦苇湿地PAHs污染现状,以湿地土壤内含量较高的芘和茚并(1,2,3-cd)芘为研究对象,在利用湿地芦苇根系分泌物去除芘和茚并(1,2,3-cd)芘的基础上结合微生物固定化技术以增加根际微生物数量和活性,提出湿地植物芦苇-固定化微生物复合系统,以强化微生物群落对高环PAHs的降解。本研究利用筛选到的两株PAHs高效降解菌(PYR1和INP1)作为微生物固定化研究的目标菌株,以工业和生活废物—煤渣作为载体材料,通过包埋法对混合菌进行固定化。然后将固定化生物煤渣粒置于芦苇根际,构建湿地植物-固定化微生物联合净化系统,并对其净化能力及添加的固定化微生物对土壤中细菌群落结构及多样性的影响进行了分析。具体的研究结果如下：(1)从长期受石油污染的滨海湿地中成功筛选出芘和茚并(1,2,3-cd)芘高效降解菌株PYR1和INP1,经16S rDNA鉴定,可确定其分别为Pseudomonas sp.和Acinetobacter sp.。以芘和茚并(1,2,3-cd)芘为唯一碳源,在无机盐培养基中培养18d后,混合菌株PYR1+INP1对芘和茚并(1,2,3-cd)芘的去除率分别为即.3%和59.8%,其对芘的去除率高于单菌,对茚并(1,2,3-cd)芘的去除效果没有单菌好。(2)煤渣、改性PVA和氯化钙的配比为100:5:2.5 (g:mL:mL)时,固定化微球的成球效果、机械强度和传质性能等综合性能较高。固定化微球的内部空间结构富含空隙,通透性增强,利于传质,适于微生物的生长。室内条件下固定化微生物对污染土壤中芘和茚并(1,2,3-cd)芘的去除研究表明,实验30d后,其去除率分别达到70.7%和80.9%,明显高于游离菌和没有包埋菌的煤渣粒的效果。这表明包埋PAHs高效降解菌的固定化生物煤渣粒明显增强了芘和茚并(1,2,3-cd)芘的去除。(3)基于滨海湿地植物和微生物固定化技术构建的芦苇—固定化生物煤渣粒复合系统对芘的去除率达59%以上,对茚并(1,2,3-cd)芘的去除率也超过了80%,说明该联合净化系统适用于滨海湿地的PAHs污染修复。此外,2组装置列PAHs不同的净化效果表明不同PAHs初始浓度对植物-固定化微生物联合净化PAHs的影响是不同的。在一定污染浓度范围内,PAHs污染物浓度越高,其去除率越高。(4)未添加固定化微生物的Shannon指数约为9.3,添加固定化微生物40d后,Shannon指数仅为5.3,固定化微生物的输入对土壤中的土著微生物产生了较大影响,降低了土壤中细菌群落的多样性。添加固定化微生物40d后,所测得的序列在纲的水平上,主要优势菌群为Gammaproteobacteria(Y-变形菌纲),占到了总群落的60%。在属水平上,优势菌为Acinetobacter sp. (12.68%)、 Pseudomonas sp. (7.4%)、Dysgonomonas sp. (3.78%),均具有高效降解PAHs的能力。
[Abstract]:The coastal wetland of Liaohe estuary has Asia's largest wetland habitat for many rare animals and plants. But due to the high strength development of the Liaohe oil field to higher content of PAHs wetland sediments and soils, and the high molecular weight (4 -6 ring ring), bio degradable PAHs accounted for nearly 50% of the total PAHs, and distribution no significant change in the whole growth season of reed. This further illustrates the effectiveness of the biological activity of microbial degradation of PAHs in wetland is lower and the aging of PAHs is relatively low. Therefore, according to the current situation of the coastal wetland PAHs pollution in Liaohe estuary, with wet soil in high content and Indeno (1,2,3-cd) pyrene pyrene as the research object, in the removal of pyrene and indene by root exudates and reed wetland (1,2,3-cd) combined with immobilized microorganism technology on the basis of pyrene in order to increase the number and activity of microorganisms in the rhizosphere of Phragmites australis, proposed immobilized micro The biological complex system, to strengthen the microbial community of high ring PAHs degradation. Two strains of PAHs degrading bacteria used in this study screened (PYR1 and INP1) as the target strain of immobilized microorganisms, to industrial and domestic waste coal cinder as carrier materials for immobilization of mixed bacteria by embedding method. Then the immobilized biological particles in the rhizosphere of reed cinder, constructed wetland plants and immobilized microorganism combined purification system, and the influence of the purification capacity and adding immobilized microorganism on the soil bacterial community structure and diversity were analyzed. The results are as follows: (1) from the coastal wetland affected by long-term oil the pollution of the screened Indeno (1,2,3-cd) pyrene and pyrene degrading strains PYR1 and INP1, by 16S rDNA identification, we can determine its Pseudomonas sp. and Acinetobacter sp.. Respectively with pyrene and Indeno (1,2,3-cd) pyrene The only carbon source in inorganic salt culture medium 18D, PYR1+INP1 mixed strains of pyrene and Indeno (1,2,3-cd) pyrene removal rates were.3% and 59.8%, the removal rate of pyrene is higher than that of single strain of Indeno (1,2,3-cd) pyrene removal no single bacteria (2). A modification of PVA and calcium chloride ratio for 100:5:2.5 (g:mL:mL), the ball effect immobilized microspheres, the comprehensive performance of the mechanical strength and mass transfer performance is high. The internal spatial structure in space, enhance the permeability of immobilized microspheres, for the mass transfer, suitable for the growth of microorganisms. In the polluted soil and Indeno pyrene immobilized microorganisms under laboratory conditions (1,2,3-cd) on the removal of pyrene showed that the experiment 30d, the removal rate reached 70.7% and 80.9% respectively, was significantly higher than that of free bacteria and no embedding bacteria particles. The effect of cinder showed that the embedded PAHs degrading bacteria immobilized biological cinder grain obviously Enhanced pyrene and Indeno (1,2,3-cd) pyrene removal. (3) the construction of coastal wetland plant and microorganism immobilization technology Reed - immobilized biological particle composite system cinder of pyrene removal rate was 59% based on the above, to Indeno (1,2,3-cd) pyrene removal rate is more than 80%, indicating that PAHs pollution remediation the purification system is suitable for coastal wetlands. In addition, the purification effect of 2 different PAHs assembly arrangement shows that the effects of different initial PAHs concentration on plant - immobilized microorganism combined with the purification of PAHs is different. In a certain concentration range, PAHs the higher the concentration of pollutants, the removal rate was higher (4) did not. Adding the immobilized microorganism Shannon index is about 9.3, adding the immobilized microorganisms 40d, Shannon index was only 5.3, immobilized microorganism input has great impact on indigenous microorganisms in the soil, and reduced the diversity of bacterial communities in soil. Adding the immobilized microorganism 40d, measured by the sequence in class level, the main dominant bacteria Gammaproteobacteria (Y- Proteobacteria), accounting for the total community 60%. at genus level, dominant bacteria were Acinetobacter sp. (12.68%), Pseudomonas sp. (7.4%), Dysgonomonas sp. (3.78%). The ability to have efficient degradation of PAHs.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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