基于氢自养反硝化的生物电化学系统脱氮性能研究

发布时间：2018-05-06 17:42

本文选题：生物电化学系统 + 氢自养反硝化　；参考：《江南大学》2017年硕士论文

【摘要】：源于工业、农业、畜牧业的大力发展,大量的氮素进入水体并不断累积,威胁到人类和其他生物的生存,含氮废水的高效处理已成为备受关注的问题。相对于传统的物理、化学及生物脱氮工艺,基于生物电化学系统(Bioelectrochemical System,BES)的反硝化脱氮技术具有效率高、能耗低、污泥产生量少等优点而备受关注。为了给BES中的脱氮行为提供更多的电子来源,本研究基于氢自养反硝化的原理,将生物制氢工艺与生物电化学系统耦合,构建了三种不同结构的生物电化学脱氮系统,包括双室BC(Biocathode)、串联式HBC(Hydrogen Facilitated Biocathode)和三室CHBC(Coupled Hydrogen and Biocathode),并从动力学、电化学、分子生物学等方面展开研究,综合比较了三组BES的运行性能,发现了三室CHBC的脱氮性能最佳。主要研究结果如下:(1)采用不同的方式对BES阳极产电菌、阴极脱氮菌、产氢菌进行了驯化,结果显示,阳极产电菌经过28 d成功驯化后,阳极电势逐步稳定在-0.55 V左右;脱氮阴极微生物经过28 d的成功驯化后,NO-3-N去除率趋于稳定;厌氧污泥经预处理消灭产甲烷菌后用于产氢菌群的驯化,驯化成功后BC、HBC、CHBC发酵气体中H2组分均稳定在40-50%之间,且无CH4气体生成。(2)NO-3-N初始浓度为130 mg/L时,CHBC、HBC和BC分别经过6 d,8 d和12d的运行可使NO-3-N降解率达到95%以上。NO-3-N降解过程中,CHBC中的NO-2-N浓度始终保持最低,其最高浓度仅为4.20 mg/L,远低于HBC(15.92 mg/L)和BC(32.56mg/L),由此表明CHBC的脱氮效率最佳,且反硝化过程更完整,而BC中脱氮途径很可能是以硝酸盐异化为主。(3)三组BES产氢过程中均发生了明显的乙酸和丁酸积累,属于典型的丁酸型发酵产氢。72 h内,HBC产酸总量最低,相应的产氢量也保持最低(32.70 m L/g VS)。CHBC的产酸总量最高,但产氢量却受到乙酸浓度的抑制,仅达到BC(50.23 m L/g VS)的75.91%;CHBC(52.49%)和HBC(45.59%)还伴有乙醇型发酵产氢,使得发酵气体中的氢含量高于BC(44.41%),并能够保证产氢体系的稳定性,从而更好地为BES脱氮提供电子。(4)CHBC拥有最大的电流(3.60 m A)和开路电压(336.7 mV),其库伦效率(79.1±0.2%)相比BC和HBC分别提高了35.21%和9.56%,其最大功率密度能够达到118.43 m W/m3,较BC和HBC分别提高了46.86%和20.10%。电化学阻抗谱的测定结果显示CHBC(35.45Ω)和HBC(39.83Ω)的极化内阻仅为BC(81.52Ω)的一半。此外,CHBC中电极膜传递电子的能力最强,且其脱氮阴极生物膜中的全细胞数量最多。因此,CHBC具有产电性能最佳,极化电阻最小,电子传递性能最佳的电化学优势。(5)利用Illumina测序技术对三组BES脱氮阴极的微生物分析得知,尽管CHBC生物多样性最低,但有5种脱氮菌属在CHBC(Simplicispira,Thauera,Thermomonas,Azoarcus,Ottowia)中得到了富集,而BC(Denitratisoma)和HBC(Thiobacillus)中仅各有1种脱氮菌得到富集,且CHBC中这7种脱氮菌属相对丰度(45.44%)远高于BC(15.13%)和HBC(15.96%),说明CHBC更适合脱氮菌群的生长,从而提高了系统的脱氮性能。此外,三组BES中均发现了少量的产氢菌属Clostridium sp.,且CHBC富集了更多的以Simplicispira为主的氢自养反硝化菌,表明CHBC中的氢自养反硝化能力更强,脱氮途径很可能以硝酸盐呼吸为主。
[Abstract]:Because of the great development of industry, agriculture and animal husbandry, a large number of nitrogen enters the water body and accumulates continuously, which threatens the survival of human and other organisms. The efficient treatment of nitrogen containing wastewater has become a concern. Relative to the traditional physics, chemical and biological denitrification processes are based on Bioelectrochemical System (BES). In order to provide more electronic sources for denitrification in BES, this study is based on the principle of hydrogen autotrophic denitrification in this study, which is based on the principle of hydrogen autotrophic denitrification, coupled with biological hydrogen production technology and biological electrochemical system, and constructed three different structures of biological electrochemical denitrification. The system, including two chamber BC (Biocathode), series HBC (Hydrogen Facilitated Biocathode) and three chamber CHBC (Coupled Hydrogen and Biocathode), has been studied from the aspects of dynamics, electrochemistry and molecular biology. The performance of the three groups of BES is compared and the best denitrification performance of the three chambers is found. The main research results are as follows: (1) The BES anode producing bacteria, the cathodic denitrification bacteria and the hydrogen producing bacteria were domesticated in different ways. The results showed that the anode potential steadily stabilized at -0.55 V after 28 d acclimation, and the removal rate of NO-3-N was stable after the successful acclimation of the denitrification cathode microorganism after 28 d; the anaerobic sludge was pretreated to eliminate methanogenic bacteria. After the acclimation of the hydrogen producing bacteria group, the H2 components in the BC, HBC, and CHBC fermented gases were stable between 40-50% and no CH4 gas after the domestication. (2) when the initial concentration of NO-3-N was 130 mg/L, CHBC, HBC and BC were passed through 6 D, 8 and 8. The highest concentration is only 4.20 mg/L, far below HBC (15.92 mg/L) and BC (32.56mg/L), which indicates that the denitrification efficiency of CHBC is the best and the denitrification process is more complete, and the denitrification pathway in BC is likely to be mainly nitrate dissimilation. (3) the accumulation of acetic acid and butyric acid in the three groups of BES production is a typical butyric acid. The total amount of acid produced in HBC was the lowest in the type of hydrogen producing.72 h, and the corresponding hydrogen production was the lowest (32.70 m L/g VS).CHBC was the highest, but the hydrogen production was inhibited by the concentration of acetic acid, only 75.91% of BC (50.23 m L/g VS); CHBC (52.49%) and 45.59% (45.59%) were accompanied by ethanol production of hydrogen, which made the hydrogen content in the fermented gas higher than that of the C (44.41%), and can guarantee the stability of the hydrogen production system, and thus better provide electrons for BES denitrification. (4) CHBC has the maximum current (3.60 m A) and open circuit voltage (336.7 mV), its Kulun efficiency (79.1 + 0.2%) increases 35.21% and 9.56% compared to BC and HBC respectively, and its maximum power density can reach 118.43 m W/m3, which is 4 higher than BC and HBC, respectively. The results of 6.86% and 20.10%. electrochemical impedance spectroscopy showed that the polarization internal resistance of CHBC (35.45 omega) and HBC (39.83 omega) was only half of BC (81.52 omega). In addition, the electrode membrane in CHBC has the strongest ability to transfer electrons and the number of all cells in the denitrogenation cathode biofilm is the most. Therefore, CHBC has the best electric property, the polarization resistance is the smallest, and the electron transfer is the least. (5) 5) microbiological analysis of three groups of BES denitrogenation cathodes by Illumina sequencing showed that 5 kinds of denitrification bacteria were enriched in CHBC (Simplicispira, Thauera, Thermomonas, Azoarcus, Ottowia), but only 1 species in BC (Denitratisoma) and HBC. The denitrification bacteria were enriched, and the abundance of the 7 denitrification bacteria in CHBC was much higher than that of BC (15.13%) and HBC (15.96%), indicating that CHBC was more suitable for the growth of the denitrification bacteria group, thus improving the system's denitrification performance. In addition, a small amount of hydrogen producing bacteria Clostridium sp. was found in the three groups of BES, and CHBC enriched more Simplicispira mainly. The hydrogen autotrophic denitrifying bacteria showed that hydrogen autotrophic denitrification was stronger in CHBC, and nitrification was probably the main way of denitrification.

【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

【参考文献】