【作者】 张鹏；

【导师】 冯传平； 郝春博；

【作者基本信息】 中国地质大学（北京） ， 生物化学与分子生物学， 2011， 硕士

【摘要】 地下水硝酸盐氮(NO3--N)的污染已成为广泛关注的环境问题。由于过度施肥以及工业、生活废水的不合理排放,使地下水中硝酸盐的浓度逐年升高。而饮用硝酸盐含量过高的水会严重威胁人类的健康。生物法是是目前应用的最经济有效的处理方法。但传统的生物反硝化法仍存在许多缺点。因此本研究针对生物法存在的不足设计了一种电极强化生物膜反应器,进行了处理地下水硝酸盐的试验研究,并运用了分子生物学手段对反应器中生物多样性进行了监测。本文研究了电极单独作用、碳氮比(C/N)、磷酸盐、电流强度对电极强化生物膜处理地下水硝酸盐处理效果的影响。试验结果表明,电极对硝酸盐的除去效果很微弱,主要作用还是水解产生氢气。碳源对电极生物膜反应器的去除效果至关重要,本实验中C/N =1.00时反应器的运行效果达到最佳,硝酸盐氮的去除率达到96%,亚硝酸盐氮的含量≤0.02mg/L,出水没有外加碳源甲醇的污染。缺少磷酸盐时,硝酸盐氮去除效果C/N=1.25、1.00时微弱下降,硝酸盐氮的去除率分别为84.6%和82.6%,在低C/N条件下明显降低,硝酸盐氮的去除率为47.6%。同时,造成了亚硝酸盐氮积累量的显著增加,出水亚硝酸盐氮的含量最高达到10mg/L左右,严重影响了出水水质。电流强度的增加对处理效果能起到促进作用,但是存在着一个极限,超过这个极限,会对处理效果起到抑制作用。在本实验中,电流强度的极限值是40mA。利用PCR-DGGE技术研究了反应器生物群落的演变规律。试验结果表明,在反应初期Acetobacterium和γ- proteobacterium的优势地位逐渐被β- proteobacterium取代。随着电流的通入, Hydrogenophaga sp、Pseudomonas sp、Alcaligenes sp、Denitratisoma sp成长迅速逐渐变成了优势菌种。总的来说,β-proteobacteria是电极强化生物膜反应器内的优势菌种。更多还原

【Abstract】 Nitrate contamination of groundwater has become a widespread concern environmental problem. Nitrate concentration in groundwater aquifers has steadily been increasing over the years mainly due to the extensive use of chemical fertilizers in intensive agriculture as well as discharge of domestic and industrial wastes. High levels of nitrate in drinking water will pose a serious threat to human health.Biological method is the most cost-effective approach. However, the traditional method of biological denitrification still has many disadvantages. In this study, a strengthening biofilm- electrode reactor has been designed for overcome the disadvantages of biological methods. The nitrate remove from groundwater by this reactor has been studied. Biological diversity of the reactor has been monitored by use of molecular biology methods.This study is to investigate the performance of the strengthening biofilm- electrode reactor affect by electrochemical reduction,C/N,phosphate and current intensity. The result show that: the nitrate remove by electrochemical reduction is very weak and the main role of electrode is the hydrogen producing by hydrolysis; Carbon source is a critical parameter. In this study, the optimum C/N is 1.00. Nitrate nitrogen removal rate reached 96%, nitrite concentration 0.02 mg/L and no methanol as carbon source found in effluent. Lack of phosphate, nitrate nitrogen removal rate slight decrease when C/N =1.25 and 1.00.The rate is 84.6% and 82.6%, respectively. At low C/N conditions, nitrate nitrogen removal rate remarkable decrease, is only 47.6%. At the same time, the accumulation of nitrite has a significant increase. Nitrite nitrogen in effluent up to 10mg/L caused a serious impact on water quality. Current intensity increase has an accelerating influence for the efficiency of strengthening biofilm- electrode reactor. However, current intensity increase exist an optimum value. Exceed this value, current intensity increase plays an inhibition role. In this study, the optimum value is 40mA.The evolution of reactor system was studied with denaturing gradient gel electrophoresis(DGGE). The results indicated Acetobacterium andγ- proteobacterium were dominant at the beginning, then progressively replaced byβ- proteobacterium. Hydrogenophaga sp,Pseudomonas sp,Alcaligenes sp,Denitratisoma sp were dominant at current has passed.In a word,β-proteobacteria is dominant in reactor.更多还原