【作者】 曲有鹏；

【导师】 Bruce E. Logan； 冯玉杰；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2013， 博士

【摘要】 水资源短缺及水污染严重已成为制约我国经济社会可持续发展的瓶颈之一。传统的废水处理技术导致了较高的化石能源需求，海水淡化技术可以增加水资源的供应量，但高能耗的问题同样制约其应用和推广，低能耗的海水淡化技术及水中有机物定向转化和能源化新方法是可持续水处理技术发展趋势。微生物脱盐电池(Microbial desalination cell, MDC)是根据生物电化学系统(Bioelectrochemical system, BES)技术衍生出来的，利用阳极上的产电微生物氧化有机物污染物产生电能，在阴阳极间形成电场推动脱盐室中盐离子去除，不需要任何外加的压力和电场即可实现同步产电、脱盐和污染物去除。然而目前MDC系统内存在的pH不平衡问题严重抑制了反应器的性能，并且空气阴极生物电化学系统中溶解氧对反应器性能影响较大，上述问题都将影响MDC系统的未来应用。本论文以MDC为研究手段，开展了新型反应器设计、海水淡化、污染物去除和溶解氧对反应器性能影响等方面研究。开发了无pH抑制效应的内循环MDC（recirculation MDC, rMDC）反应器。利用反应器阳极室和阴极室产生的酸碱相互中和以消除反应器内pH不平衡，运行周期内可保持溶液pH近中性的环境，MDC阳极溶液pH=5.0为反应器性能降低的拐点，阳极溶液pH＜5.0时由于产电菌的活性受到抑制反应器性能迅速下降。rMDC的最大功率密度和COD去除率远高于MDC反应器，在25mM PBS条件下rMDC的NaCl去除率比MDC反应器提高了48%，而50mM PBS时却比MDC降低了13%，高缓冲盐浓度增加了底物循环过程中阴阳极室间的电势损失，rMDC在低缓冲液条件下的优异性能可以降低其在实际应用中因污水电导率较低产生的影响。在rMDC基础上设计并构建了四个反应器单元串联的连续流微生物脱盐燃料电池（串联MDC）。四个反应器单元的最大功率密度均高于间歇流运行的普通三室MDC，通过增加串联MDC单元数目可以有效提高污染物的处理能力。盐溶液HRT延长脱盐效果随之提高，盐溶液HRT为1d时NaCl去除率为76±1%，HRT增加到2d时NaCl去除率提高到97±1%。阳极微生物16S rDNA基因文库结果显示，兼性厌氧微生物Klebsiella ornithinolytica为各单元中最优势菌群，能够发酵木糖产生多种小分子的混合酸，推测其功能为严格厌氧的产电微生物提供厌氧环境，维持产电系统的稳定。探索了使用青贮秸秆和啤酒废水两种废弃生物质为底物驱动串联MDC实现同步产电脱盐的可行性。青贮秸秆水洗液作为碳源和同时作为碳源、氮源时MFC反应器的最大功率密度分别为847±3mW·m-2和609±3mW·m-2。分别以青贮秸秆水洗液和啤酒废水运行串联MDC时，青贮秸秆水洗液为底物的反应器NaCl去除率可达到74±2%（盐溶液HRT=1d）和96±2%（盐溶液HRT=2d）。不添加任何缓冲液直接进啤酒废水的反应器COD去除率在75%-83%之间， NaCl去除率为50%-55%。研究了空气阴极MES系统中溶解氧对反应器性能的影响。开发了用于纯菌研究的空气阴极立方体反应器，通过研究非产电菌Escherichia coli和产电菌Geobacter sulfurreducens在不同运行模式反应器中的性能，发现溶解氧浓度变化与反应器输出电压之间密切联系，随着混合培养反应器内溶解氧浓度降低输出电压逐渐升高，而纯培养反应器均无明显电压产生。混合培养时E. coli消耗掉溶液中的溶解氧，为厌氧产电菌G. sulfurreducens创造厌氧环境，维持其代谢活性并产生电能。更多还原

【Abstract】 The shortage of water resources and water pollution have restricted theeconomic and social sustainable development. Although seawater desalinationtechnology can increase the supply of fresh water, high energy consumptionrestricts its application and enlargement. Traditional wastewater treatment processesalso needed large amount of fossil energy. The desalination of low energyconsumption, directed transfer of organic matter in water and energy collection isthe development trend of sustainable water treatment.A microbial desalination cell (MDC) is a new type of bioelectrochemicalsystem (BES) that can simultaneously desalinate water, produce electrical current,and treat waste water. The ions in the salty water are transported through therespective AEM and CEM membranes when current is generated by theexoelectrogenic bacteria to balance charge in the anode chamber from release ofprotons, and in the cathode chamber by the consumption of protons. This results indesalination of the salty water without the use of any external energy source.However, a low pH can develop in the MDC anode chamber that inhibits bacterialactivity and the higher catholyte pH also can result in potential losses, limiting theextent of water desalination and electricity generation. Dissolved oxygen has beenshown to adversely affect reactor performance. These all restricts its futureapplications. In present thesis, research works were performed focusing on the newreactor configuration, seawater desalination, pollutant removal and influence ofdissolved oxygen.In this study, we designed and operated a recirculation microbial desalinationcell (rMDC) that recirculates the solutions between the anode and cathode chambers.This recirculation avoided pH imbalances and bacterial respiration inhibition. Acomparison of the anode potentials and anode pH suggests that a pH<5.0substantially reduced MDC performance due to adverse effects of low pH onmicrobial activity. Both maximum power density and COD removal of rMDC werehigher than that of MDC. The extent of desalination using the rMDC is a48%increase in performance compared to reactors operated in MDC mode with25mM PBS, although it is slightly less (13%) than that compared with the MDC with50mM PBS. The reduction in performance results from a potential losses when thesolutions were mixed between the electrode chambers, with a greater effect for thehigher PBS concentration. The lower concentration of PBS in rMDC with betterdesalination efficiency showed well potential in the practical application.A series of hydraulically connected MDCs was designed based on rMDC andoperated under continuous flow. The power densities of each unit reactor are muchgreater than those previously obtained using three-chamber MDCs when they wereoperated under fed batch conditions. COD removal of series of hydraulicallyconnected MDCs was improved compared to a single MDC. The NaCl removal was76±1%at an HRT=1d, and increased to97±1%at an HRT=2d. These results showthat increasing the HRT enhanced NaCl removal as a result of the longer period oftime for desalination. The most abundant sequences were most similar to Klebsiellaornithinolytica, which is a facultative anaerobe that can ferment D-xylose to mixedacids and butanediol. This suggests that this microbe would have been able toconsume dissolved oxygen and help maintain anaerobic conditions forexoelectrogenic bacteria in the air-cathode MDCs while degrading the xylose.Corn silage and beer brewery wastewater was demonstrated as substrate inseries of hydraulically connected MDCs. The maximum power densities were847±3mW m-2using corn silage washing liquid as carbonsource and609±3mWm-2as carbon and nitrogen sources in air-cathode MFC. When the series ofhydraulically connected MDCs was fed with corn silage washing liquid, the NaClremoval was74±2%at an HRT=1d and96±2%at an HRT=2d. The COD removaland NaCl removal is75%-83%and50%-55%, respectively, when the substratesolution was change to brewery wastewater without any buffer.A air-cathode MFC for pure culture was developed to study the nteraction ofmicroflora. Oxygen has been shown to adversely affect current generation by otherexoelectrogens. When the co-culture reactors were operated with a closed circuit,the dissolved oxygen in the bulk solution was rapid decrease.But no electricity wasproduced by pure cultures of G. sulfurreducens or E. coli. These results show thatoxygen consumption by E. coli created sufficiently anaerobic conditions for currentgeneration by G. sulfurreducens.更多还原