嗜酸性硫杆菌的分离纯化及其应用研究

发布时间：2017-12-26 22:23

本文关键词：嗜酸性硫杆菌的分离纯化及其应用研究　出处：《南京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：针对酸洗污泥的减量化与资源化问题,现有的火法、湿法和固化等处置方法存在着二次污染、经济性差、有效资源无法回收利用等问题。本研究富集培养嗜酸性硫杆菌,探究生物法在酸洗废弃物处理领域的可行性。对江苏省重点地区的不锈钢企业进行采样分析,得出酸洗废水进水的pH在2-3左右,经石灰和碱液中和沉淀后,出水的pH在6-7左右。酸洗污泥的pH基本呈碱性,在8-9左右,含水率大约在70%～80%。酸洗废水和酸洗污泥中Fe、Ca含量最高,平均含量分别为13.63%和27.57%；重金属Ni、Cr的含量突出,平均含量分别为2.26%和2.77%；酸根离子含量最高的为F,平均含量达到23.57%。从南京市城东污水处理厂的二沉池中富集培养菌株作为实验菌株,经分离鉴定为嗜酸性硫杆菌,命名为Acidithiobacillus ferrivorans NJUST22。分别讨论初始pH、亚铁浓度和温度对菌株活性的影响,确定最佳运行参数,即菌株可以利用亚铁作为能源,最适pH为2.5,温度为30℃。由于酸洗废水和酸洗污泥中含有一定量的重金属和酸根离子,会对菌株产生潜在的毒害作用,需研究对其的耐受性。结果表明：菌株可耐受600mg/L的重金属离子Cr3+和Ni2+; NO3-、Cl-、SO42-、PO43-要达到0.3mol/L时才会出现强烈的抑制作用；而F-仅需0.01mol/L就会对菌株活性造成强烈的抑制。嗜酸性硫杆菌在培养过程中,使整个培养基pH降低,以达到浸出污泥中重金属的目的。但由于酸洗污泥pH过高和氟离子浓度过高两个原因,会一定程度抑制菌株的活性,导致整个培养基pH下降缓慢,重金属离子的浸出率较低。当初始亚铁浓度为5.0g/L时,重金属Cr3+和Ni2+的浸出率分别达到34.87%和85.37%,过高的初始亚铁浓度反而会导致浸出率的下降。考察初始pH、亚铁浓度和温度对生物法合成黄钾铁矾的影响,对黄钾铁矾进行物相分析,并探究其对废水中重金属离子的去除效果。结果表明：菌株的活性决定了黄钾铁矾的生成量,但初始pH低于2.0、温度低于20℃以及培养基中的亚铁浓度过低时都不利于黄钾铁矾的生成。黄钾铁矾样品由形状不规则的小颗粒胶连在一起组成,分散性好。样品的平均粒径为17.74μm,分布较均匀。生物法合成黄钾铁矾时,酸洗废水(出水)中Cr3+的去除率较高,最高可达到87.02%,Ni2+的去除率相对较低,最高可达到55.30%。
[Abstract]:Aiming at the problem of reduction and reuse of acid sludge, the existing fire, wet and solidification disposal methods have two problems, such as pollution, poor economy, and effective resources can not be recycled. This study enriched and cultured eosinophilic bacilli, and explored the feasibility of biological method in the field of acid washing waste treatment. Sampling and analyzing the stainless steel enterprises in key areas of Jiangsu Province, it is concluded that the pH of the pickling waste water is about 2-3, and the pH of the effluent is about 6-7 after neutralization and precipitation by lime and alkali. The pH of the pickling sludge is basically alkaline, at about 8-9, and the water content is about 70% ~ 80%. The contents of Fe and Ca in acid pickling wastewater and acid washed sludge were the highest, the average contents were 13.63% and 27.57% respectively. The contents of heavy metals Ni and Cr were outstanding, the average contents were 2.26% and 2.77% respectively, and the highest content of acid ion was F, with an average content of 23.57%. From the two sink of Chengdong wastewater treatment plant in Nanjing, the strain was selected as an experimental strain and identified as acidophilic Thiobacillus, named Acidithiobacillus ferrivorans NJUST22. The effects of initial pH, ferrous concentration and temperature on the activity of bacteria were discussed respectively, and the best operation parameters were determined. That is, strain can use ferrous as energy source, the optimum pH is 2.5, and the temperature is 30 C. Because of a certain amount of heavy metals and acid ion in pickling and pickling sludge, it will have potential toxicity to the strain, and it is necessary to study its tolerance. The results showed that the strain could tolerate heavy metal ions Cr3+ and Ni2+ of 600mg/L, while NO3-, Cl-, SO42- and PO43- had strong inhibition when 0.3mol/L reached 0.3mol/L, while F- only needed 0.01mol/L, which strongly inhibited the activity of strain. In the process of culture, Thiobacillus eosinophilia reduces the whole medium pH to achieve the purpose of Leaching Heavy Metals in sludge. However, due to two reasons of high pH and high fluoride concentration, the activity of the strain will be inhibited to a certain extent, resulting in a slow decline of pH in the whole culture medium and a low leaching rate of heavy metal ions. When the initial ferrous concentration is 5.0g/L, the leaching rates of heavy metals Cr3+ and Ni2+ reach 34.87% and 85.37% respectively. The higher initial ferrous concentration will lead to the decrease of leaching rate. The effects of initial pH, ferrous concentration and temperature on biotic synthesis of jarosite were investigated. Phase analysis of jarosite was carried out and its removal effect on heavy metal ions in wastewater was explored. The results showed that the activity of the strain determined the production of jarosite. However, when the initial pH was below 2, the temperature was below 20 C, and the ferrous concentration in the medium was too low, it was not conducive to the generation of jarosite. The samples of potassium ferric alum are made up of small particles with irregular shape, and have good dispersibility. The average particle size of the sample is 17.74 m, and the distribution is more uniform. In the process of biological synthesis of jarosite, the removal rate of Cr3+ in acid washing wastewater (effluent) is high, the highest can reach 87.02%, and the removal rate of Ni2+ is relatively low, up to 55.30%.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;X172

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