【作者】 陈佩；

【导师】 颜家保；

【作者基本信息】 武汉科技大学 ， 化学工程与技术， 2015， 硕士

【摘要】 焦化废水中的主要污染物来源于炼焦过程所产生的剩余氨水,其所含的酚类、杂环类、多环芳烃类和苯系物类均对微生物有一定或较强的生物毒性。这些毒性化合物对微生物具有明显生长抑制作用,导致焦化废水经传统生物处理后仍部分残留影响废水达标排放。近年来,采用生物强化技术对焦化废水开展了大量的研究,以往的研究主要集中于酚类和氮杂环类,针对苯系物的研究还鲜有报道。本文以邻二甲苯为目标污染物,从长期受焦化废水污染的土壤中分离出一株邻二甲苯高效降解菌,通过菌落形态观察、革兰氏染色和生理生化实验,以及16S rDNA测序分析对菌株进行种属鉴定,研究其生长及降解特性、降解动力学和降解广谱性,并将其与本实验室保藏的另外6株高效菌构建复合菌,对复合菌的生长和降解特性及对焦化废水的生物强化效果进行了考察。本论文主要研究结论如下:1.以邻二甲苯为唯一目标底物,筛选得到一株邻二甲苯高效降解菌OX5,结合菌株OX5的生理生化特征和16S rDNA测序分析结果,将菌株OX5归属为绿脓假单胞菌属(Pseudomonas aeruginosa sp.)。2.菌株OX5适宜的生长和降解条件为:培养温度30~35℃,培养基初始pH=7.0~8.0,摇床转速150 r/min,接种量2vol%;邻二甲苯质量浓度达到200 mg/L时,开始抑制菌株的生长繁殖;OX5对邻二甲苯的降解过程符合Monod动力学方程,当邻二甲苯浓度ρ?64.32 mg/L时,OX5降解速率达到43.29 mg/(L·h)。3.酚类降解菌(F、LF1)、氮杂环类降解菌(Q、P3)、烷烃降解菌C16、萘降解菌N和邻二甲苯OX5按LF1:P3:C16:F:OX5=2:2:1:2:1比例构建的复合菌对焦化废水COD的降解效果最好;复合菌适宜的生长条件为:培养温度30℃,初始pH=7.0~8.0,摇床转速200 r/min。4.以葡萄糖为外加碳源时,COD去除率由48.5%提高到了58.3%,添加蔗糖时影响较小;以蛋白胨为外加氮源时,COD的去除率最高,达到了54.2%,加入尿素或硝酸钾时的效果不及使用蛋白胨和硫酸铵。5.与单一菌株相比,复合菌具有更宽的底物利用范围和更大的脱氢酶活性,且对废水COD的去除率增加了19%~29%;在摇瓶实验中,“复合菌+活性污泥”可在72 h内将焦化废水中的COD去除87.3%。更多还原

【Abstract】 Coking wastewater mainly from the coking produced in the process of surplus ammonia water, containing pollutants including phenols, heterocyclic or polycyclic aromatic hydrocarbons and benzene series. These compounds have a certain or strong risk of biological toxicity to microbe which can inhibit its growth, and the traditional biological treatment doesn’t eliminate the residue completely and it cannot satisfy the needs for environment protection. In recent years, many experts and scholars did substantive research in the field of coking wastewater by adopting the bioaugmentation technology and achieved significant progress. But majority of the former research relate only to phenols and N- heterocyclic and few deal with benzene series.In this study, o-xylene was used as the target pollutant and one high efficiency bacterium was isolated from coking-wastewate-contaminated soil. First, morphological observation, gram stain, physiological and biochemical properties and 16 S rDNA sequence were analyzed to identify the strain. Then, the growth and degradation conditions, the degradation kinetics and the range of substrate degradation were investigated. Finally, compound bacteria with the strain and the other six high efficiency strains were built, then its growth characteristics and bioaugmentation in coking wastewater were discussed. The main research conclusions of this study are as follows:1. O-xylene was used as the target substrate and a high efficiently degradation bacterium OX5 was isolated. The strain was identified as Pseudomonas aeruginosa sp. by physiological and biochemical characteristics test and 16 S rDNA sequence identification.2. The optimum temperature, initial pH, shaker rotary speed and bacterialload for OX5 was 30~35 ℃, pH 7.0~8.0, 150 r/min and inoculating quantity 2%, respectively. O-xylene started to inhibit OX5 proliferation when its mass concentration reached up to 200 mg/L. The degradation of o-xylene on strain OX5 follows the Monod kinetic equation, and when the initial o-xylene mass concentration ρ?64.32 mg/L, the degradation rate was 43.29 mg/(L·h).3. Compound bacteria which composed of strains for phenols(F、LF1)、strains for N- heterocyclic(Q、P3)、strain for alkane C16、strain for naphthalene N、strain for o-xylene OX5 at the ratio of LF1:P3:C16:F:OX5=2:2:1:2:1 had the highest degradation rate to COD of coking wastewater. The optimum temperature, initial pH and shaker rotary speed was 30 ℃, pH 7.0~8.0 and 200 r/min.4. The removal rate of COD increased from 48.5 % to 58.3% with glucose, however sucrose hardly had an effect on it. It had a best influence on the removal of COD while adding peptone as nitrogen source, the removal rate was up to 54.2%, and the effect of adding carbamide or KNO3 is less than using peptone or(NH4)2SO4.5. Comparing with the single strain, compound bacteria had a wider range of substrate degradation and the larger dehydrogenase activity, and could increase the removal rate of COD by 19%~29%. The COD could be removed 87.3% within 72 h on “compound bacteria+ activated sludge” in flask-shaking.更多还原