阴极菌群对MFC脱氮产电及动力学影响

以硝酸盐溶液为阴极电子受体,在阴极室分别接种活性污泥菌群和反硝化菌群,分别构建了生物阴极型微生物燃料电池A-MFC和D-MFC。考察两种阴极菌群MFC的脱氮与产电性能,通过动力学模型对硝酸盐降解过程进行分析。结果表明,阴极菌群的不同会对MFC脱氮与产电性能造成影响,反硝化菌群对硝酸盐有更好的亲和能力和更大的耐受程度。     

单室不锈钢阳极微生物燃料电池强化反硝化的研究

采用碳布阴极,不锈钢阳极构建了以葡萄糖为唯一电子供体、硝酸盐作为电子受体管状单室微生物燃料电池(MFC),研究MFC的COD、NO3-去除情况和强化反硝化性能。在室温下,初始COD为595 mg/L,外接电阻100、1000Ω时,该MFC去除率为62%、56%,比厌氧对照组高10%~15%,NO3-去除率为60%、58%,比厌氧对照组高10%。表明该MFC在能良好降低COD的同时,也能够很好的去除硝酸盐,并且强化了反硝化过程,是一种很高效的去除硝酸盐的方法。给我们在MFC的研究和硝酸盐的降解中提供了一个新的方向,对加深理解MFC机理,推动MFC技术发展和降解硝酸盐的水处理的应用具有理论与实际意义。     

微生物燃料电池在污水生物脱氮中的研究进展

微生物燃料电池(MFC)是一种新型污水处理技术,其在处理污水的同时能产生电能,引起众多研究者的关注.将MFC应用于含氮污水的处理中便形成了反硝化或同步硝化反硝化MFC系统.本文回顾了MFC生物脱氮的发展历程,并从MFC实验装置的设计构造(空间构型、电极材料、分隔材料)、影响因素(含氮污染物浓度、水力停留时间、溶解氧、碳源与碳氮比、温度、pH值、外电阻)和反硝化细菌的基因表达与多样性等3个方面进行了综述与分析,提出需要从以下方面进行MFC生物脱氮效能的强化:开发具有强电子传输能力和氨氧化催化功能的廉价高效电极材料,优化MFC脱氮的运行条件和探索不同环境下的脱氮机理,通过研究MFC阴极微生物种群构成筛选培育优势反硝化功能菌.     

单室型无质子膜微生物燃料电池协同去除COD和含氮污染物

分别驯化、培养厌氧消化菌和反硝化菌,以间距180μm(80目)的不锈钢网为电极,构建了单室型无质子交换膜微生物燃料电池(MFC)污水处理系统,厌氧消化菌在阳极附着成膜组成生物阳极氧化去除有机污染物,反硝化菌在阴极附着成膜组成生物阴极反硝化去除含氮污染物,实现污水深度处理。在电池系统稳定运行期间,最高开路电压为182.5 mV时,COD的去除率为96.5%;NH4+-N和NO3-N的去除率分别高于93.5%和96.7%,出水中NO2-N的含量低于0.072 mg L 1。当阳极室和阴极室分开时,COD、NH4+-N和NO3-N的最大去除率之和分别为67.0%、76.9%和84.0%,均明显低于阳极室和阴极室连通的MFC系统的去除率,这表明该MFC系统具有良好的有机污染物和含氮污染物协同去除能力。     

以琼脂凝胶为碳源和载体的水源水生物脱氮

针对受硝酸盐污染的水源水,建立了以琼脂凝胶为反硝化菌的碳源和微生物载体的反应器,通过生物反硝化作用去除水源水中的硝酸盐.试验结果表明,在水源水自然接种的条件下,通过微生物的驯化培养可以顺利启动琼脂凝胶反应器;系统的反硝化效果受水力停留时间(HRT)和进水DO质量浓度的影响较明显,进水NO3-N质量浓度对系统的反硝化能力有一定的影响,同时改变进水方式可以进一步提高反硝化效率;在温度为21～23℃、进水NO3-N质量浓度为24.74mg·L-1、HRT为7.1 h、进水DO质量浓度不控制的条件下,NO3-N的去除率能达到76.25‰此时出水COD和NO2-N质量浓度分别为16.57mg·L-1和0.387mg·L-1.研究指出,琼脂凝胶生物反硝化系统能够有效地脱除水源水中的硝酸盐氮.     

利用氢自养反硝化菌处理硝酸盐污染地下水的研究

讨论了氢自养反硝化菌的驯化培养方法及氢自养反硝化菌在厌氧条件下利用氢气作为电子供体还原硝酸盐的可行性,试验建立了氢自养反硝化茵生物量的定量方法,每单位OD600相当于水样中氢自养反硝化菌的生物量浓度为491.74 mg·L-1;讨论了硝酸盐底物浓度对氢自养反硝化菌反硝化性能的影响,硝酸盐浓度超过150mgNO3-N·L-1时,反硝化菌的活性会受到抑制;在氢自养混合茵初始生物量25 mg·L-1左右,硝酸盐浓度为100mgNO3-N·L-1以下时,反硝化时间21 h可以达到硝酸盐的彻底还原.     

电极-SBR法处理城市污水脱氮除磷的研究

本论文研究的目的在于研究电场与生物协同作用下,SBR法去除污水中氮磷的效果。实验结果表明,电极-SBR法比传统的SBR法在脱氮除磷方面,都有比较明显的提高。实验还揭示：由于电场的作用,造成了电极表层的氧气浓度降低,抑制了硝化/亚硝化菌的生长,并在电解的过程中为反硝化提供H＋作为电子受体,促进了反硝化反应。而阴极板上产生的氢气形成了缺氧环境,反硝化菌可能在缺氧的条件下利用氢作为载体对硝酸盐氮、亚硝酸盐氮进行彻底的氧化还原成氮气。     

饮用水中硝酸盐的去除

作为重要的饮用水源,地下水中硝酸盐的污染日趋严重,硝酸盐对人体健康有严重的危害。物化方法(离子交换、电渗析、反渗透等)、生物反硝化、化学反硝化等工艺都可不同程度地去除作为饮用水的地下水中的硝酸盐,这些方法各有优缺点。本文综述了地下水中硝酸盐去除方法的应用和研究现状,并对其发展趋势做了简单的讨论。     

短程电极生物膜处理养殖废水中高氨氮的试验研究

为了探索高氨氮水产养殖废水处理新技术,采用短程电极生物膜工艺同时在硝化区、反硝化区各设1组电源控制反应。研究结果显示:亚硝化细菌利用好氧区阳极碳棒电解产生的氧使氨氮转化为亚硝酸盐氮;反硝化菌利用反硝化区阴极碳棒电解产生的氢实现脱氮。实验的主要影响因素是p H和温度,反硝化区的电流对实验有一定的促进作用,次要的影响因素为C/N、水力停留时间和氨氮浓度。     

地下水硝酸盐氮污染原位修复研究进展

可渗透反应墙(PRB)技术是一种经济、高效、节能的地下水污染原位修复方法。阐述了PRB去除地下水中硝酸盐的反应机理、墙体结构,分析比较了零价铁还原原位修复、零价铁还原/生物反硝化联合原位修复、自养反硝化修复地下水氮污染以及适合地下水硝酸盐去除的异养生物反硝化的碳源材料等研究进展,指出了各工艺的不足之处和研究方向,展望了PRB技术原位修复地下水氮污染的发展前景。     

Enhanced denitrification through microbial and steel fuel-cell generated electron transport

Enhancement of nitrate reduction was studied in a two-chambered microbial fuel cell (MFC) and a similar abiotic fuel cell (steel fuel cell or SFC) with an oxidizable steel wool anode and catalyst-free stainless steel mesh cathode. In the MFC and SFC systems, nitrate was reduced in the cathode chamber at 11.4 or 40.0 mg nitrate/L/day, respectively. The MFC utilized petroleum compounds in refinery wastewater as the electron donor and the SFC utilized steel wool as the electron donor. Oxidation of the petroleum compounds in the MFC and steel wool in the SFC caused electron flow from the anode to the cathode, where nitrate was reduced. Nitrate reduction was significantly (P < 0.001) higher in SFCs with non-sterile groundwater in the cathode chambers and the flow of electrons to the cathode stimulated microbial growth. Our results suggest the both MFC and SFC designs could serve as electron source for nitrate reduction at the cathode. Particularly the SFC could be an innovative low-cost, low-maintenance alternative for in situ remediation of nitrate-contaminated groundwater.     

Influence of NO3 and SO4 on power generation from microbial fuel cells

Potential competition in terms of electron transfer from bacteria to electron acceptors such as nitrate (NO₃) and sulfate (SO₄) or the anode of a microbial fuel cell (MFC) was investigated to determine how alternative electron acceptors would influence power generation in an MFC. The cell voltage was not initially affected when these electron acceptors were introduced into the MFCs. However, the presence of NO₃ decreased the CE of the MFC compared to the injections of SO₄ or control salt (sodium chloride). This suggests that the growth of nitrate-reducing bacteria independent of the microbial populations on the MFC anode were not utilizing the anode as an electron acceptor, rather, they were consuming organic carbon in the anodic chamber of the MFC, resulting in a decrease of the CE of this MFC with no immediate impact on power output. This suggests that the bacterial consortium in the nitrate-MFC still preferred the anode over nitrate as the electron acceptor, although the theoretical reduction voltage of nitrate (+0.74 V) is higher than the reduction voltage in an MFC air cathode (as high as +0.425). These results are useful when considering whether MFC technology can be applied in situ to enhance biodegradation of organic contaminants in the presence of alternative electron acceptors.     

AD-MFC中甲醇与硝酸盐的偶合过程与作用机制

在双室微生物燃料电池(MFC)阳极内接种反硝化细菌富集培养物,同时加入硝酸盐和甲醇,构建了阳极反硝化微生物燃料电池(AD-MFC),并以批式操作研究了AD-MFC的反硝化产电性能。试验结果表明,在初始硝氮浓度为(100.22±0.62)mg·L^-1,COD浓度为(500.40±1.67)mg·L^-1的条件下,AD-MFC的最大容积NO₃^--N和COD去除速率分别达到0.31 kg N·m^-3·d^-1和1.06 kg COD·m^-3·d^-1,最大电压达到(602.80±5.42)mV,相应最大功率密度为(908.42±0.07)mW·m^-3。AD-MFC的产电过程是甲醇氧化与硝酸盐还原的偶合过程,电压变化与反硝化作用密切相关,可用于指示反硝化进程。AD-MFC的电压曲线呈现降低-升高-再降低的三阶段特性,其原因是反硝化作用、甲醇降解作用和细胞水解发酵作用依次成为阳极液中的主导反应。     

Electricity generation with simultaneous wastewater treatment by a microbial fuel cell (MFC) with Cu and Cu–Au electrodes

Background: A microbial fuel cell (MFC) consisting of anaerobic and aerobic chambers separated by a salt‐agar slab was used for electricity generation with simultaneous wastewater treatment where copper and gold covered copper wires were used as anode and cathode, respectively. The electrons produced from degradation of carbohydrates in anaerobic chamber traveled through the copper wire generating electricity and the protons were transferred from cathode to anode through the salt‐agar slab. Variation of the current intensity (mA) and the electrical power (mW) were investigated as function of the surface area of anode and also the chemical oxygen demand (COD) content of the synthetic wastewater. Results: The generated power density (mW m^?2) increased with increasing surface area of the electrodes and also with the COD content of the wastewater. Both the current intensity (mA) and the power generated (mW) increased with time and reached maximum levels at the end of batch operation. More than 80% COD removal was achieved in the aerobic chamber with an electricity generation of 2.9 mW m^?2 when the initial COD content was 6000 mg l^?1. Conclusion: The MFC configuration and the use of Cu and Cu‐Au electrodes instead of graphite were proven to be effective for electricity generation with simultaneous wastewater treatment. The electrical current (0.24 mA) and power (2.9 mW m^?2) obtained in our microbial fuel cell are comparable with the literature studies utilizing salt bridge. The microbial fuel cell developed in this study can be improved further to yield higher power generations by modifications. Copyright © 2007 Society of Chemical Industry     

典型大环内酯类抗生素污染物生物电化学降解研究

对利用单室空气阴极微生物燃料电池(MFC)降解水中红霉素(ERY)进行了研究。结果表明,ERY的加入使MFC阳极上的产电菌活性受到抑制,ERY浓度越大,对产电菌抑制性越强。当ERY质量浓度为30 mg/L时,MFC最大功率密度为400 mW/m^2,ERY降解率为(83.21±1.4)%,COD去除率为(84.91±2.1)%。加入ERY后,阳极微生物群落发生改变,但主要物种相同且数量较大,厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)和变形菌门(Proteobacteria)这3类产电菌门为微生物燃料电池的性能发挥了重要作用。     

异养反硝化微生物燃料电池脱氮产电性能研究

构建了双室型微生物燃料电池(MFC),探讨了异养反硝化底物降解、产电特性和指示作用。结果表明:有机物是影响异养反硝化微生物燃料电池产电和污水处理性能的关键影响因素,未加入有机物时MFC产电仅有10 m V;MFC的电信号能较好地反映亚硝氮、COD基质浓度的变化情况,因此可用电压变化指示底物的降解过程;在不考虑菌体水解、同化作用所引起氨氮浓度的增加问题时,亦可用时间来指示氨氮的降解过程。     

Microbial community dynamics and electron transfer of a biocathode in microbial fuel cells

Microbial community dynamics and its electron transfer process within a biocathode in a microbial fuel cell (MFC) were investigated in this study. The MFC was operated steadily over 400 days, and the power density reached 1.92 and 10.27 W/m³ based on the reduction of nitrate and oxygen, respectively. The six major groups of the clones that were categorized among the 26 clone types were Proteobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Firmicutes and uncultured bacteria. Microbial community dynamics showed that Betaproteobacteria was replaced by Gammaproteobacteria as the most abundant division among all the clone types with a percentage of 48.86% in the cathode compartment, followed by 20.45% of uncultured bacteria, 17.05% of Bacteroidetes, and others. Distinct oxidation and reduction peaks could be observed in the profiles of cathodic effluent during the cyclic and differential pulse voltammetry tests. It confirmed that nitrate and oxygen reduction in the cathode compartment could be significantly enhanced by the presence of microbes, which are able to excrete metabolites to assist the electron transfer process either in the anode or in the cathode compartment.     

Nitrate remediation in a novel upflow bio-electrochemical reactor (UBER) using palm shell activated carbon as cathode material

This study investigated the biological denitrification method which is a treatment method able to reduce inorganic nitrate compounds to harmless nitrogen gas. Autohydrogenotrophic denitrifying bacteria were used in this study to prevent any problematic outcomes associated with heterotrophic microorganisms. An upflow bio-electrochemical reactor (UBER) was used to accommodate hydrogenotrophic denitrifying bacteria employing palm shell granular activated carbon (GAC) as the biocarrier and cathode material. Bicarbonate as the external inorganic carbon source was fed to the reactor and hydrogen as the electron donor was generated in situ through electrolysis of water. Central composite design (CCD) and response surface methodology (RSM) were applied to investigate the effects of two operating parameters, namely electric current (I) and hydraulic retention time (HRT), on performance of the UBER. Electric current range of 0-20 mA and HRT range of 6-36 h were examined and results showed that nitrate can be entirely reduced within application of a wide operational range of electric current (10-16 mA) as well as HRT (13.5-30 h). However, increase of pH at cathode zone up to 10.5 inhibited nitrite reduction, and it was not reduced to the satisfactory level.