【作者】 王卫娜；

【导师】 李建政；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2008， 硕士

【摘要】 连续流搅拌槽式反应器(CSTR)系统内微生物群落均成絮状结构,并且在搅拌状态下很难得到结构良好的颗粒污泥,因此常被用来作为产酸发酵及发酵生物制氢的装置。CSTR属悬浮絮状厌氧活性污泥系统,在传质和反应速度上较颗粒污泥系统具有明显优势,但目前尚无采用CSTR成功培养完整厌氧消化体系的研究报道。论文借助于两种结构型式的CSTR,在前期成功培育出具有完整甲烷发酵微生物系统的基础上,探讨了CSTR甲烷发酵系统向产酸发酵系统转化的运行控制对策,以期为以下两个方面的应用奠定基础:(1)CSTR厌氧消化系统的运行控制;(2)借助于产酸发酵菌群和产氢产乙酸菌群的生物质深度发酵产氢技术的研发。研究证明,采用好氧活性污泥为种泥,以稀释糖蜜为底物,在控制进水COD浓度7000 mg/L、HRT 18 h、温度35±1℃、pH 6.5～7.5等条件下,通过改变HRT和系统pH,可以实现CSTR甲烷发酵系统向产酸发酵系统的转变。主要调控方式为逐渐缩短HRT致8 h,之后逐渐降低系统pH值,使其保持在5.0左右。反应器运行稳定时未检出CH4,H2含量达到21.6%,液相末端产物VFAs总量达到1992mg/L,其中乙酸、丙酸、丁酸、戊酸和乙醇的百分含量分别为36%、27%、4.5%、2%和30%,呈现混合酸发酵特征。为了在CSTR反应系统中建立以产酸发酵菌群和产氢产乙酸菌群为优势的微生物群落,本论文研究了向CSTR甲烷发酵系统中投加特异性产甲烷菌抑制剂的控制方法。首先,利用选择性丁酸培养基,通过摇瓶试验,比较了特异性产甲烷菌抑制剂氯仿和2-溴乙烷磺酸钠的作用特征,发现2-溴乙烷磺酸钠具有更明显的产甲烷菌活性抑制作用,并初步确定2-溴乙烷磺酸钠的投加量为10 mmol/L。根据静态试验结果,通过进水向CSTR甲烷发酵系统连续投加2-溴乙烷磺酸钠,投加浓度分阶段依次提高,最终在CSTR反应系统内成功抑制了产甲烷作用。转化后的CSTR发酵系统,产气速率稳定在9 L/d,H2含量稳定在2.6%,CH4未检出;液相末端发酵产物VFAs总量达到3357mg/L,其中乙酸、丙酸、丁酸、戊酸和乙醇的百分含量分别为40%、38%、7%、4.2%和7%,呈现典型的丙酸型发酵。更多还原

【Abstract】 The anaerobic active sludge in CSTR has obvious advantages on mass-transfer and reaction rate compared with granular sludge resulted in the suspended flora. However, there are few reports in culturing anaerobic flora with a function of methane production in CSTR. Anaerobic flora with a function of methane production had bred in two CSTRs in previous study. The engineering control measures of transformation from methane fermentation system to acidogenic fermentation system were investigated in this paper. The results would lay a foundation for the application in the following two respects: (1) the engineering control of anaerobic digestion system in CSTR; (2) developing a new hydrogen-producing fermentation process, in which acidogens and hydrogen-pruducing acetogens could degrade organic material step by step and more hydrogen yield could obtained..The results indicated that a transformation from methane fermentation system to acidogenic fermentation system could carry out in CSTRⅡunder the following condition: influent COD 7000 mg/L (diluted molasses), hydrolic retention time (HRT) 18 h, pH 6.5～7.5 and a temperature of (35±1)℃. And then, the reactor was operated by shortenning HRT from 18 h to 8 h stage by stage and decreased the pH in the system to 5.0. When the fermentation system reached its steady state, methane was not detected in the biaogas and hydrogen content achieved 22%. The total liquid fermentation products was 1992 mg/L, among which the contents of acetic acid , propionic acid , butyric acid, pentanoic acid and ethanol were 36 %、27 %、4.5 %、2 % and 30 %respectively, indicating a typical mixed acid fermentation had occurred in the CSTRⅡ.In order to establish a microbial community dominated by acidogens and hydrogen-producing acetogens, specific methanogen inhibitor (2-bromoethanesuLfonate) was put in CSTRⅠcontinuously. The results indicated that methanogesis could be inhibited completely in CSTRⅠwhen the dose reached at above 10 mmol/L and an acidogenic fermentation system was obtained. When the system reached its steady state, the biogas yield kept about 9 L/d with a hydrogen content of 2.2%, with no CH4 been detected. The total liquid fermentation products reached 3357 mg/L, among which the percentage of acetic acid,propionic acid,butyric acid,pentanoic acid and ethanol were 40%, 38%, 7%, 4.2% and 7% respectively, indicating a typical propionic acid type fermentation in CSTRⅠ.更多还原