【作者】 刘伟佳；

【导师】 吴军虎；

【作者基本信息】 西安理工大学 ， 农业水土工程， 2010， 硕士

【摘要】 通过查阅文献资料,采用室内试验与理论分析相结合的技术路线,研究了不同影响因素条件下污水入渗水分及污染物在土壤-地下水中的运移规律。主要研究成果为：(1)研究了不同地下水埋深条件下均质土壤毛管水上升运动特性。毛管水上升过程以上升速率为依据可划分为上升和稳渗两个阶段,上升阶段毛管水平均上升速率与地下水埋深成正相关关系,稳渗阶段成负相关关系。(2)对比分析了不同地下水埋深条件下,污水入渗水分及污灌物在土壤-地下水中的运移规律。地下水埋深的不同导致了土壤初始含水量分布和污灌物迁移路径的差异；土壤入渗量随地下水埋深的增大而增大；埋深越浅,入渗结束时的入渗率越小；氯离子与SO42-在土壤中分布规律相似,入渗后其淋洗量随地下水埋深的增大而减小,埋深深,迁移路径长,土体内含水量低,污灌物易累积在土壤中,地下水中增量小；土体内氯离子淋洗量大于SO42-,地下水增量大于SO42-；埋深浅,高土水势能和反硝化潜势制约了污水携带NO3--N向下层土壤迁移淋失的趋势,但高土水势能和短迁移路径使下层土壤基质中的NO3--N易被挤入至地下水中,NO3--N污染地下水风险较大。(3)研究了不同土壤质地条件下,污水入渗水分及污灌物在土壤-地下水中的运移规律。土壤初始含水量随质地的变重而增加；土壤入渗量随质地的变重而减小；质地越重,土壤中氯离子SO42-累积量就越大,地下水中增量越少；氯离子污染地下水的程度大于SO42-；质地越重,NO3--N在土壤中运移的距离越小,土壤中累积NO3--N量越多,地下水中NO3--N浓度的增幅越小。(4)研究了不同夹砂层粒径条件下,污水入渗水分及污灌物在土壤-地下水中的运移规律。砂层对土壤毛管水上升高度有明显的抑制作用,水分未穿越砂层；砂层的阻水作用随砂层粒径的变粗而增强；有夹层各处理土壤中氯离子和NO3--N累积含量均大于均质土,地下水中氯离子和NO3--N增量小于均质土；砂层粒径越粗,受上层土壤和砂层内氯离子和NO3--N的补给量越大,地下水中氯离子和NO3--N增量越大。(5)研究了不同夹砂层层位条件下,污水入渗水分及污灌物在土壤-地下水中的运移规律。砂层层位越高,对土壤毛管水上升高度的抑制作用越明显。入渗相同灌水量所需时间为：层位80cm>均质土>层位10cm>层位45cm。不同砂层层位抑制污水入渗氯离子的程度不同,层位10cm和80cm入渗后土体内水分分布连续,层位10cm的抑制能力小于80cm,入渗后地下水中氯离子浓度大于后者。层位45cm上下水力不连续,地下水中氯离子增幅最小。不同砂层层位对土壤NO3--N分布和转化规律有明显的影响,地下水中NO3--N变化规律与氯离子相似。更多还原

【Abstract】 Based on consulting a great deal of literature from the domestic and foreign and adopted technique way of indoor experiment and theoretical analyses, the paper mainly studies the transport rule of water and pollutants in soil and groundwater under waste water infiltration in various conditions. The main results are as follows:(1) The rise characteristic of capillary water in homogeneous soil under groundwater depth was researched. Capillary water upward process can be divided into two stages of rising and steady infiltration according to capillary upward rate, capillary upward average rate of rise is positively related to groundwater depth in stages of rising, and negatively correlated with groundwater depth in stable stages.(2) The transport rule of water, nitrogen, chloride and sulfate in soil and groundwater under waste water infiltration in different groundwater was researched. Different groundwater depth led to the difference in soil moisture distribution and the migration path of sewage irrigation pollutants. Infiltration capacity increased with the in increased groundwater depth. Infiltration rate decreased with the increased groundwater depth at the time that the infiltration was over. The chloride had a similar distribution rules with the SO42- in the soil and groundwater. Their leaching and washing decreased with the increased groundwater depth after infiltration, The longer the migration path and the more the soil moisture content, the deeper the groundwater depth, chloride are easier to stagnate in soil, by contrast, accrual of chloride in groundwater decreased. Leaching and washing of chloride in soil and accrual in groundwater is greater than SO42-. Although the higher of soil moisture potential energy and denitrification were restricted to tendency of NO3--N in sewage from up to down, but the higher of soil moisture potential energy and shorter migration path stimulate NO3--N of soil matrix from subsoil to groundwater, the pollution risk of groundwater increased with the groundwater depth.(3) The transport rule of water, nitrogen, chloride and sulfate in soil and groundwater under waste water infiltration in different soil texture was researched. Initial soil moisture content with the increased soil texture. Infiltration capacity of soil with the decreased soil texture. The cumulant of chloride and SO42- in soil increased with an increase of soil texture, and their increment decreased. Leaching and washing of chloride in soil and accrual in groundwater is greater than SO42-. The pollution level of groundwater caused by chloride is greater than SO42-.NO3--N transport distance in soil and NO3--N content increased amplitude in groundwater also decreased with the increased soil texture.(4) The transport rule of water, nitrogen and chloride in soil and groundwater under waste water infiltration in different soil particle size of sand layer was researched. Because of sand layer has an obvious inhibitive effect on the height of capillary ascension, anastaticwater not penetrate sand layer. Prevent water action was enhanced with increasing soil particle size of sand layer. The cumulant of chloride and NO3--N in soil is greater than homogeneous soil, by contrast, accrual of chloride and NO3--N in groundwater is less than homogeneous soil. Supply amount of chloride and NO3--N from above layer and sand layer increases as particle size of sand rises, and their increment in groundwater also increases as particle size of sand rises.(5) The transport rule of water, nitrogen and chloride in soil and groundwater under waste water infiltration in different sand layer depth was researched. The smaller the sand layer depth, the inbibitional effect of capillary upward water height more obvious. The process of infiltration With the same irrigation reuirement need time as follow:sand layer depth lie on 80cm> homogeneous soil> sand layer depth lie on 10cm> sand layer depth lie on 45cm. The inbibitional effect of chloride by different layer depth in varying degrees, water distribution is continuous in sand layer depth lie on 10cm and 80cm after infiltration, the chloride ion in the groundwater is more than the latter because of inbibitional effect is less than the latter. Chloride ion increment in groundwater is least in sand layer depth lie on 45cm because soil water distribution is noncontinuous. The sand layer the principles of NO3--N transformation and transport in soil can be influenced by the changes of sand layer depth, the changes of NO3--N in groundwater is similar to chloride ion.更多还原