【作者】 夏琼；

【导师】 钱家忠；

【作者基本信息】 合肥工业大学 ， 环境工程， 2008， 硕士

【摘要】 地下水既是一种宝贵的自然资源,又是环境的基本要素。当今世界所面临的“人口,资源,环境”三大问题,都直接或间接地与地下水资源有关。随着人口的增长、城市规模的不断扩大及工农业的迅速发展,人类对地下水的污染越来越严重。其中硝酸盐是世界上许多地区地下水污染最普遍的环境因子,并且污染程度不断增加。硝酸盐污染在我国的情形也相当严重,并且呈恶化趋势。巢湖是被国家列为重点治理的“三河三湖”其中之一。近年来,湖泊富营养化日趋严重,一个重要原因即是非点源的氮磷污染。合肥滨湖新区位于巢湖和合肥老城区之间,其地下水受人类活动影响较大,具有典型性,而且该区还是流域地下水系统与滨湖地表水系统发生相互作用的一个重要场所。因此,论文结合国家自然科学基金（40672154）和教育部新世纪优秀人才计划项目（NCET-06-0541）,开展“合肥滨湖新区地下水环境特征及硝酸盐去除实验研究”具有理论和实际意义。本文在收集了国内外相关研究成果和合肥滨湖新区地貌、地质、水文地质条件以及地下水水化学监测数据等资料的基础上,采用了因子分析和模糊综合评价的方法,对其水环境质量进行分析。根据污染状况,以滨湖地带重点污染带为靶区,进行了硝酸盐去除实验研究,得出主要结论如下:（1）研究区地下水的水化学类型主要为HCO₃—Na和HCO₃—Ca型,其中Ca-Na-Mg-HCO₃-Cl类型水较多和Ca-Na-Mg-HCO₃类型所占比例偏大;（2）滨湖地区硝酸盐严重超标,污染范围较大,污染程度达到47.3%。氨氮和亚硝酸盐局部超标,污染范围小;（3）使用因子分析法,在对污染分区的基础上,得出相关系数矩阵。根据因子分析碎石图和旋转后的因子荷载散点图,选择各个分区的主因子,得到地下水各种化学成分对硝酸盐空间差异性的影响类型。结果表明:NH₄⁺,NO₂^-,Ca²⁺,Mg²⁺对NO₃^--N的污染起正向作用,而SO₄^2-,HCO₃^-,pH对NO₃-N的污染起负向作用;（4）模糊综合评价法得出研究区的水质总体为Ⅲ类水,总体水质良好;（5）尝试使用现场取样,培养反硝化菌群进行修复实验,结果表明:随着时间的增加,硝酸盐含量逐渐降低,最大降解效率达到57.67%;氨氮含量呈现先减少后增加的趋势;亚硝酸盐含量呈现先增加后减少的趋势,主要由于中间过程中亚硝酸盐含量的累计。硝酸盐含量与pH值成负相关,与DO值成正相关。为了加强反硝化的效率,可适当调节其pH值接近7,DO含量在0～3mg/1之间。在浅层土壤中,反硝化作用随着深度的增加,效果增强。更多还原

【Abstract】 The groundwater is not only a precious natural resources, but also a basic element of environment. It is relative to the three problems about "population, resource and enrivonment" directly or indirectly. The pollution of groundwater is more seriously as the increasing population, expanding city size and developing industry and agriculture. The nitrate is a universal environmental factor in most areas of the world and contamination degree is increasing continuously. In our country, the status is serious and present a deteriorative tendency.Chaohu is one of the " three rivers and three lakes" ,which our country do key harmassment on it. In recent years, the stuation of lake eutrophication is more seriously, one of the important reason is non-point source nitrogen and phosphorus. New Lakeshore District locates between Chaohu and old town of Hefei, it is a typical district that its groundwater is impacted greatly by human activities. The district is an important site which interact groundwater system of basin with surface water of lakeshore. So, combined the National Natural Science Foundation of China （No.40672154） and the Program for New Century Excellent Talents in University （No. NCET-06-0541）, the title of "hydrochemical characteristics and experimental study of nitrate removal in New Lakeshore District of Hefei city" is determined. It is of theoretical and practical significance.This paper analyzes the water environment quality by the measures of factor analysis and fuzzy comprehensive evaluation method on the basis of the results of international and national research and data gathering, which is about the geomorphy, geology, hydrogeologic condition and the chemical data of groundwater in the New Lakeshore District, Hefei. Nitrate experimental research to the New Lakeshore District have been done according to the pollution status. Conclusions are drawn as follows:（1） The hydrochemistry type of the groundwater in the target area is HCO₃-Na and HCO₃-Ca, which the type of Ca-Na-Mg-HCO₃-Cland Ca-Na-Mg-HCO₃ have large proportion.（2） The nitrate pollution in the most part of New Lakeshore District is out of extent and the range is large which is up to 47.3%. Ammonia and nitrogen is out of extent in some areas and the range is small.（3） The correlation coefficient matrices are obtained based on pollution zoning by factor analysis method. The impact types which chemical contents in the groundwater relative to nitrate spatial difference are obtained by choosing major factors of different zones according to factor analysis gravel diagrams and factor load scatter diagrams after rotation.the results shows that: NH₄⁺, NO₂^-. Ca²⁺, Mg²⁺ are positive correlation to the NO₃^--N pollution, while SO₄^2-, HCO₃^-, pH are negative correlation to the NO₃^-N pollution.（4）Fuzzy comprehensive evaluation shows that: the level of water quality is three grade in the target area and the water quality is good.（5）Try to use field sampling and carry out the recovery experiment by culturing denitrification microflora. The result shows that: nitrate content is gradually decreased with the prolonging of time, the maximum degradation efficiency is up to 57.67%; ammonia content present a tendency of decreasing at first and then increasing; nitrite content present a tendency of increasing at first and then decreasing, it’s dominating causes to the accumulation of nitrite. Nitrate content is negative correlation to the pH, and is positive correlation to the DO. In order to strengthen the efficiency of denitrification, pH value can be adjusted to 7 and DO content may be between 0 and 3 mg/1. In shallow soil, the efficiency of denitrification is increasing as the increased depth.更多还原