活性污泥中降解煤菌种的选育及其降解效果研究

发布时间：2018-03-29 12:11

  本文选题：活性污泥　切入点：煤生物降解　出处：《天津理工大学》2017年硕士论文

【摘要】：我国是煤炭储量和消耗量大国。目前,煤炭最主要的利用方式是燃烧。煤炭的直接燃烧会造成严重的环境污染,使雾霾天气增多。因此,如何实现煤炭的清洁转化,是我国践行人与自然和谐共生理念必须面对的课题。本研究的主要目的是从活性污泥中筛选出能够降解煤的微生物,为煤生物降解在菌种选育方面提供新的方向,为煤的生物降解利用的进一步研究提供理论基础。首先,将富集培养之后的污泥上清液转接至含有50m L无机盐培养液和0.5g煤的锥形瓶中培养。观察发现,实验组瓶中有气泡浮在液面,而对照组中没有;实验组煤样的电镜图和红外光谱图表明,煤样表面空隙增大,煤样中分子结构发生变化;实验组上清液元素分析结果显示,上清液中Ca、Mg和P的含量有所减少,Zn的含量有所增加。以上变化表明活性污泥中存在能够降解煤的微生物,证实从活性污泥中筛选能够降解煤菌种的可行性。其次,利用控制变量的方法对泥碳比进行优化;利用Minitab设计中心复合实验对无机盐培养液的成分进行优化;利用正交实验(三因素三水平)对培养温度、煤样预处理方法和pH进行优化。最终得到微生物降解煤的最佳培养方案,即泥3g、煤样0.5g、无机盐培养液50mL、未经处理煤样、培养温度35℃和pH设为8。其中无机盐培养液的成分为:磷酸二氢钾的浓度为1.1g/L,氯化钙的浓度为1.1g/L,硫硫酸铁的浓度为0.4/L,酸镁的浓度为0.1g/L,氯化钠的浓度为0.5g/L,硝酸铵的浓度为5g/L,。再次,利用Z字划线方法从活性污泥中分离菌种,将得到的5种菌种回接至无机盐培养液为50mL和煤样为0.5g的锥形瓶中恒温培养。上清液元素分析结果表明接入菌种Z1的上清液中Ca、Mg、P和Zn元素含量较对照组有所变化,接入其余菌种的上清液元素含量变化不大;煤样红外光谱分析结果表明,经过菌种Z1、Z2和Z3作用后的煤样中芳环结构和含氧官能团均有所变化,而接入其余菌种的煤样分子结构变化微小;菌种Z1、Z2和Z3作用后的煤样电镜图显示,其煤样松散程度增加。因此,最终筛选出能够降解煤的菌种Z1、Z2和Z3。菌种Z1的降解率最大。利用水浸片和革兰氏染色法初步分析得到:菌种Z1为放线,菌种Z2为毛霉菌,菌种Z3为酵母菌。最后,研究菌种Z1、Z2和Z3对煤的降解效果。利用ICP-OES等离子光谱仪分析液态降解产物,结果表明Ca元素、Mg元素和P元素的含量减少,Zn元素含量增加,这说明在微生物降解煤的过程中,培养液中部分元素被利用,煤中部分元素析出;利用红外光谱分析固态降解产物,结果表明煤样中芳环结构相对增多,含氧官能团和C≡C键相对减少,这说明产物中有芳环结构生成,降解过程中有氧化水解作用发生。降解率的计算结果显示,多种菌种联合作用的降解效果好于单一菌种。其中菌种Z1、菌种Z2和菌种Z3共同对煤样进行降解的降解率最好。
[Abstract]:China is a big country in coal reserves and consumption. At present, the most important way to use coal is combustion. Direct combustion of coal will cause serious environmental pollution and increase haze weather. Therefore, how to realize clean conversion of coal, The main purpose of this study is to screen out the microorganisms that can degrade coal from activated sludge and to provide a new direction for the breeding of coal biodegradation. It provides a theoretical basis for further study on the biodegradation and utilization of coal. Firstly, the sludge supernatant after enrichment and culture is transferred to a conical bottle containing 50 mL inorganic salt and 0.5 g coal. There were bubbles floating in the bottle in the experimental group, but not in the control group. The electron microscope and infrared spectra of the coal sample in the experimental group showed that the void on the surface of the coal sample increased and the molecular structure of the coal sample changed; the element analysis of the supernatant of the experimental group showed that, The contents of Ca, mg and P in the supernatant decreased and the content of Zn increased. The above changes indicated that there were microorganisms capable of degrading coal in the activated sludge, which proved the feasibility of screening the bacteria that could degrade the coal from the activated sludge. The sludge / carbon ratio was optimized by the method of controlling variables, the composition of inorganic salt culture solution was optimized by Minitab design center compound experiment, and the culture temperature was optimized by orthogonal experiment (three factors and three levels). The pretreatment method and pH of coal sample were optimized. Finally, the optimum culture scheme of microbial degradation of coal was obtained, that is, mud 3g, coal sample 0.5g, inorganic salt culture solution 50mL, untreated coal sample, untreated coal sample, untreated coal sample, untreated coal sample, untreated coal sample. The culture temperature is 35 鈩，

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