微生物燃料电池强化去除地下水硝酸盐的研究

发布时间：2018-02-16 13:09

本文关键词： 硝酸盐去除反硝化作用电刺激微生物燃料电池生物电化学反应器　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：硝酸盐在缺氧条件下会转化为亚硝酸盐和亚硝胺类物质,对人体有致癌作用。相比于物理、化学处理工艺,生物法有更高的去除效率和环境友好性,而提高其去除效率是目前本领域的研究重点。本研究利用微生物燃料电池所产生的微电流强化反硝化作用,分别从可行性、机理以及影响因素三个方面展开研究,从而提升硝酸盐的去除效率,并实现生物电能的原位利用,为微生物的微电刺激提供了可靠的理论分析和实验支持。实验结果表明:(1)经过可行性研究,将微生物燃料电池作为电源为BER供电,以5 h为一个测定周期。对电压、硝氮、亚硝氮、氨氮和化学需氧量(COD)分别进行监测。且以不加电的生物反应器作为对照,从而对比微电流对BER的影响。结果表明,微生物燃料电池电压在500~700 m V时,相比不加电反应器,BER硝氮去除加快,且副产物积累减少。因此低电压对微生物反硝化起到了刺激的作用。(2)机理的研究方面,通过最大或然数法(MPN)计数和ATP分析得到了BER加电前后的微生物的数量和活性,并通过电学指标的监测与计算,排除了物理化学作用的影响,结果表明,加电的反应器相对于不加电的来说,数量增长了一个数量级,而活性在一个完整周期内,加电的BER中微生物的活性约为不加电反应器的1.5倍。从而确定是低电压促进了微生物的增殖,并提高了微生物活性,从而提升了反硝化速率。(3)基于已得到的结论,将微生物燃料电池的电压控制在500-700 m V范围内,利用响应曲面法,对BER中的进水硝酸盐氮浓度、COD浓度和水力停留时间(HRT)三个因素进行了优化,最终以硝氮去除率最高,副产物积累最少作为目标,得到了COD=849.66 mg/L,NO3--N=60 mg/L,HRT=3.92 h的最优结果。综上所述,来自于微生物燃料电池的微电流刺激能够提升BER中的微生物活性及数量,从而提高了硝氮的去除效率,减少了副产物的积累。且通过条件优化,得到了最优的运行结果,为工艺的实际应用提供了借鉴。
[Abstract]:Nitrate can be transformed into nitrite and nitrosamines under hypoxia conditions, which has carcinogenic effect on human body. Compared with physical and chemical treatment, biological process has higher removal efficiency and environmental friendliness. To improve the removal efficiency is the focus of this field. In this study, micro-current enhanced denitrification produced by microbial fuel cells is studied from three aspects: feasibility, mechanism and influencing factors. In order to improve the removal efficiency of nitrate and realize the in-situ utilization of bioelectric energy, it provides reliable theoretical analysis and experimental support for microorganism micro-electric stimulation. The microbial fuel cell was used as the power supply for BER. The voltage, nitrate, nitrite, ammonia nitrogen and chemical oxygen demand (COD) were monitored in a 5 h period. The unpowered bioreactor was used as the control. The results show that when the voltage of microbial fuel cell is 500 ~ 700mV, the removal of nitrate-nitrogen is faster than that of non-rechargeable reactor. And the accumulation of by-products decreased. Therefore, the number and activity of microbes before and after BER charging were obtained by maximum probability method (MPN) counting and ATP analysis in the study of the mechanism of low voltage stimulation to microbial denitrification. Through the monitoring and calculation of electrical indexes, the effect of physical and chemical action is excluded. The results show that the quantity of the reactor with power is increased by an order of magnitude, and the activity is within a complete cycle. The activity of microorganism in the electrified BER is about 1.5 times of that in the non-electrified reactor. It is confirmed that the low voltage promotes the microbial proliferation and the microbial activity, thus increases the denitrification rate. The voltage of microbial fuel cell was controlled in the range of 500-700mV. By using response surface method, three factors of nitrate concentration and HRT in BER were optimized. Finally, the removal rate of nitrate was the highest. The minimum by-product accumulation was the target, and the optimum result of COD=849.66 / L ~ (10) -N ~ (60 mg / L) ~ (60 mg / L) HRT was 3.92 h. In conclusion, the micro-current stimulation from microbial fuel cell could enhance the microbial activity and quantity in BER, and thus improve the removal efficiency of nitrate. The byproduct accumulation is reduced and the optimal operation result is obtained by optimizing the conditions, which provides a reference for the practical application of the process.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X523;TM911.45

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