零价铁对UASB-MFC耦合系统污泥颗粒化性能及生物传感性能的影响研究

发布时间：2018-04-30 09:16

本文选题：微生物燃料电池 + 升流式厌氧污泥床　；参考：《天津工业大学》2017年硕士论文

【摘要】：升流式厌氧污泥床(Up-flow Anaerobic Sludge Blanket,UASB)-微生物燃料电池(Microbial Fuel Cell,MFC)生物传感器因其能够对UASB运行状态进行稳定监测而被广泛研究。颗粒污泥作为UASB-MFC耦合系统稳定运行的关键,因其具有较高的生物活性,助于快速降解有机物,利于生物传感,而零价铁(Zero-valent Iron,ZVI)具有吸附作用,能使微生物快速聚集。因此本文将零价铁应用于UASB-MFC耦合系统中,研究ZVI对污泥颗粒化的影响;此外,由于UASB-MFC耦合系统受水解酸化及MFC电子传递等影响,从而导致生物传感性能受阻,响应时间长。因而利用ZVI较强的还原性能研究其对生物传感的影响。根据课题的实验研究与分析,得出如下结论:1.零价铁能够有效促进污泥颗粒化进程。通过不同ZVI浓度投加后反应器状况对比,反应器R1(ZVIOmg/L)内污泥平均粒径由52μm增长到851μm,而投加零价铁后颗粒平均粒径的增大,其中R4(ZVI 30mg/L)中粒径增加最多,由55μm增加至1332μm,且其大颗粒污泥所占比例较高。除此之外,零价铁促进系统内胞外聚合物中蛋白质的分泌,使污泥絮凝性能得到改善,同时相对应的降低Zeta电位,说明适量零价铁能够有效促进污泥颗粒化进程。2.零价铁对于强化生物传感器产电性能与传感性能具有一定作用。通过对比电信号和pH对浓度变化的反馈时间,得出电信号对浓度的反馈比pH的反馈更加快速。在500-2000mg/L范围内,ZVI不仅能够加速电信号及pH反馈速率,缩短反馈时间,且能对电信号起到扩增作用;在2000-6000mg/L范围内,ZVI的投加反而会对pH的反馈有所延滞。通过电化学测试得出,投加零价铁能够提升MFC的功率密度及库伦效率,降低内阻。由于零价铁增加溶液的离子强度,能够提升细菌和阳极表面电子的传递,使其电化学活性增强,助于MFC的电子传递过程,益于生物传感器性能提升。3.零价铁能提高水解酸化效率并优化产酸类型。当有机负荷为0.36gCOD/gMLSS·d时,各系统TVFA均维持在70mg/L,且VFA成分以乙酸为主,达到50%,ZVI对于VFA成分影响并不明显;在有机负荷为4.32gCOD/gMLSS·d时,系统负载过大,出现酸化状态,ZVI0mg/L时TVFA为1424mg/L,而随着ZVI投加量增加,TVFA显著降低,ZVI 50mg/L时,TVFA为814mg/L,下降43%。零价铁的加入使反应器内丁酸占总挥发性脂肪酸比例降低6%-21%,乙酸含量增加8%-21%。零价铁对水解酸化的强化效应,可对降低后续处理负荷、形成更有利的有机酸形式起促进作用。
[Abstract]:Up-flow Anaerobic Sludge Blanketn UASBM-microbial Fuel Cell-MFC biosensor has been widely studied for its ability to monitor the stability of UASB operation in Up-flow anaerobic sludge bed. Granular sludge is the key to the stable operation of UASB-MFC coupling system, because of its high biological activity, which is helpful to the rapid degradation of organic matter and is beneficial to biosensor, and Zero-valent Iron-Iron-ZVI) has the adsorption function, and can make the microorganism gather rapidly. In this paper, zero-valent iron is applied to the UASB-MFC coupling system to study the effect of ZVI on sludge granulation. In addition, the UASB-MFC coupling system is affected by hydrolytic acidification and MFC electron transport, which results in hindered biosensor performance and long response time. Therefore, the effect of ZVI on biosensor was studied by using its strong reduction property. According to the experimental research and analysis of the subject, the following conclusion is drawn: 1. Zero valent iron can effectively promote sludge granulation process. After adding different ZVI concentration, the average particle size of sludge increased from 52 渭 m to 851 渭 m in reactor R1 + ZVI Omg / L, and the average particle size increased after adding zero valent iron, in which the particle size of R4(ZVI 30 mg / L increased the most. It was increased from 55 渭 m to 1332 渭 m, and the proportion of large granular sludge was higher. In addition, zero-valent iron can promote the secretion of protein in extracellular polymer, improve the flocculation performance of sludge, and reduce the Zeta potential, which indicates that zero-valent iron can effectively promote the process of sludge granulation. 2. Zero valent iron plays an important role in enhancing the electrical and sensing properties of biosensors. By comparing the feedback time of electric signal and pH on the change of concentration, it is concluded that the feedback of electric signal to concentration is faster than that of pH. ZVI can not only accelerate the feedback rate of electric signal and pH, shorten the feedback time, but also amplify the electric signal in the range of 500-2000mg/L, but delay the feedback of pH in the range of 2000-6000mg/L. The results of electrochemical test show that adding zero valent iron can improve the power density and Coulomb efficiency of MFC and reduce the internal resistance. By increasing the ionic strength of the solution, the zero-valent iron can enhance the electron transfer between bacteria and anode surface, and enhance the electrochemical activity of the solution, which is beneficial to the electron transfer process of MFC and the performance of biosensor. 3. Zero valent iron can improve the efficiency of hydrolysis and acidification and optimize the type of acid production. When the organic load was 0.36gCOD/gMLSS d, the TVFA of each system was maintained at 70 mg / L, and the VFA component was mainly acetic acid, and the effect on the composition of VFA was not obvious when the organic load was 50% 4.32gCOD/gMLSS d, but the system load was too large when the organic load was 4.32gCOD/gMLSS d. The TVFA of ZVI0 mg / L was 1424 mg / L, while with the increase of ZVI dosage, the TTV FA of ZVI 50mg/L decreased by 814 mg / L, and decreased by 43%. The ratio of butyric acid to total volatile fatty acids in the reactor was reduced by 6- 21 with the addition of zero valent iron, and the content of acetic acid increased by 8- 21. The strengthening effect of zero valent iron on hydrolysis and acidification can promote the formation of more favorable organic acid form by reducing the load of subsequent treatment.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;TP212.3

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