基于可渗透反应格栅的地下水中2，4-二氯酚溶质运移模拟研究
发布时间：2019-05-12 17:07
【摘要】：氯酚类化合物(CPs)是一类对人体具有巨大危害的有机污染物,其特点是难以降解、持久性强。氯酚的难降解性使其在自然环境中可以长期存留,延长降解周期,很难去除。2,4-二氯酚(2,4-DCP)是其中一种,对地下水环境具有很大危害,由于人们缺乏对2,4-DCP在地下水环境中迁移转化规律的认识,一些针对性的地下水修复技术难以得到很好的应用。所以研究地下水中2,4-DCP在多孔介质中的迁移转化规律,探索其迁移转化过程,对治理在地下水环境中2,4-DCP污染具有重要意义。本文在实验室地下水原位修复模拟平台建立的基础上,模拟实际的地下水环境,保证本次研究试验数据的准确性与可靠性。用海藻酸钠包覆的粗砂承载零价铁粉混合填料作为反应格栅填料,避免了多孔介质中分散脱离现象的发生。同时,为构建2,4-DCP的迁移转化模型,设计静态吸附试验、连续流动态示踪试验和相关计算确定迁移转化模型的参数。本文通过吸附试验确定粗砂和粗砂承载零价铁的吸附平衡方程为Freundlich吸附方程,吸附系数分别为4.45635E-6和0.00846,弥散系数为0.345 cm2/min,孔隙度为0.38,给水度为0.1,渗透系数为4.15×10-2cm/s,渗流速度为1.245×10-4cm/s。根据模拟地下水流场初始条件及边界条件等,本文分别构建地下水流数学模型和溶质运移数学模型,运用Newton-Raphson迭代法进行求解。对TOUGHREACT模型软件的理论背景和计算方法进行分析,TOUGHREACT进行物理化学数值模拟过程采用了顺序迭代法(SIA),模型先进行水流方程的求解,之后水流速度和相饱和度数值会被直接用于化学溶质运移模拟过程。本文构建了地下水中2,4-DCP化学反应和溶质运移耦合模型,运用TOUGHREACT模型软件模拟地下水环境中2,4-DCP迁移转化过程,PRB反应器内和出水处2,4-DCP随时间变化的试验测定值(实测值)和模型计算值(模拟值)快速反应期能够较好的拟合,说明模型中很好的处理了2,4-DCP在反应介质中吸附等化学反应。由于2,4-DCP实测值干扰因素较多,因此出现2,4-DCP随时间变化升降趋势。但整体上,2,4-DCP实测值和模拟值具有良好的拟合效果。
[Abstract]:Chlorophenol compound (CPs) is a kind of organic pollutant which has great harm to human body, which is difficult to degrade and persistent. Chlorophenol is difficult to degrade, which makes it possible to retain chlorophenol for a long time in the natural environment, prolong the degradation cycle and is difficult to remove. 2, 4-dichlorophenol (2, 4 脳 DCP) is one of them, which is very harmful to groundwater environment. Due to the lack of understanding of the migration and transformation of 2, 4 DCP in groundwater environment, some targeted groundwater remediation techniques are difficult to be well applied. Therefore, it is of great significance to study the migration and transformation law of 2 / 4 DCP in groundwater in porous media and to explore its migration and transformation process in order to control the pollution of 2 / 4 DCP in groundwater environment. In this paper, based on the establishment of laboratory groundwater in situ remediation simulation platform, the actual groundwater environment is simulated to ensure the accuracy and reliability of the test data. The mixed packing of zero valence iron powder coated with sodium alginate was used as the reaction grille packing to avoid the phenomenon of dispersion separation in porous media. At the same time, in order to construct the migration and transformation model of 2, 4 DCP, the static adsorption test, continuous flow state tracer test and related calculation were designed to determine the parameters of the migration and transformation model. In this paper, the adsorption equilibrium equation of coarse sand and coarse sand bearing zero valence iron is determined by adsorption test as Freundlich adsorption equation, adsorption coefficient is 4.45635E-6 and 0.00846, dispersion coefficient is 0.345 cm2/min, porosity is 0.38, The water supply degree is 0.1, the permeability coefficient is 4.15 脳 10 ~ (- 2) cm / s, and the seepage velocity is 1.248 脳 10 ~ (- 4) cm / s. According to the initial conditions and boundary conditions of simulated groundwater flow field, the mathematical models of groundwater flow and solute transport are constructed and solved by Newton-Raphson iteration method. The theoretical background and calculation method of TOUGHREACT model software are analyzed. The physical and chemical numerical simulation of TOUGHREACT is carried out. The sequential iterative (SIA), model is used to solve the water flow equation first. Then the water velocity and phase saturation values will be directly used to simulate the chemical solute transport process. In this paper, the coupling model of chemical reaction and solute transport in groundwater is constructed, and the transfer and transformation process of 2,4 DCP in groundwater environment is simulated by TOUGHREACT model software. The experimental measured values (measured values) and model calculated values (simulated values) of 4 DCP over time in the PRB reactor and at the outlet of the DCP can be well fitted. The results show that the chemical reactions such as adsorption of 2, 4 脳 DCP in the reaction medium are well dealt with in the model. Because there are many interference factors in the measured values of 2, 4 DCP, there is a rising and falling trend of 2, 4 DCP with time. On the whole, the measured and simulated values of 2,4-DCP have good fitting effect.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X523
本文编号：2475535
[Abstract]:Chlorophenol compound (CPs) is a kind of organic pollutant which has great harm to human body, which is difficult to degrade and persistent. Chlorophenol is difficult to degrade, which makes it possible to retain chlorophenol for a long time in the natural environment, prolong the degradation cycle and is difficult to remove. 2, 4-dichlorophenol (2, 4 脳 DCP) is one of them, which is very harmful to groundwater environment. Due to the lack of understanding of the migration and transformation of 2, 4 DCP in groundwater environment, some targeted groundwater remediation techniques are difficult to be well applied. Therefore, it is of great significance to study the migration and transformation law of 2 / 4 DCP in groundwater in porous media and to explore its migration and transformation process in order to control the pollution of 2 / 4 DCP in groundwater environment. In this paper, based on the establishment of laboratory groundwater in situ remediation simulation platform, the actual groundwater environment is simulated to ensure the accuracy and reliability of the test data. The mixed packing of zero valence iron powder coated with sodium alginate was used as the reaction grille packing to avoid the phenomenon of dispersion separation in porous media. At the same time, in order to construct the migration and transformation model of 2, 4 DCP, the static adsorption test, continuous flow state tracer test and related calculation were designed to determine the parameters of the migration and transformation model. In this paper, the adsorption equilibrium equation of coarse sand and coarse sand bearing zero valence iron is determined by adsorption test as Freundlich adsorption equation, adsorption coefficient is 4.45635E-6 and 0.00846, dispersion coefficient is 0.345 cm2/min, porosity is 0.38, The water supply degree is 0.1, the permeability coefficient is 4.15 脳 10 ~ (- 2) cm / s, and the seepage velocity is 1.248 脳 10 ~ (- 4) cm / s. According to the initial conditions and boundary conditions of simulated groundwater flow field, the mathematical models of groundwater flow and solute transport are constructed and solved by Newton-Raphson iteration method. The theoretical background and calculation method of TOUGHREACT model software are analyzed. The physical and chemical numerical simulation of TOUGHREACT is carried out. The sequential iterative (SIA), model is used to solve the water flow equation first. Then the water velocity and phase saturation values will be directly used to simulate the chemical solute transport process. In this paper, the coupling model of chemical reaction and solute transport in groundwater is constructed, and the transfer and transformation process of 2,4 DCP in groundwater environment is simulated by TOUGHREACT model software. The experimental measured values (measured values) and model calculated values (simulated values) of 4 DCP over time in the PRB reactor and at the outlet of the DCP can be well fitted. The results show that the chemical reactions such as adsorption of 2, 4 脳 DCP in the reaction medium are well dealt with in the model. Because there are many interference factors in the measured values of 2, 4 DCP, there is a rising and falling trend of 2, 4 DCP with time. On the whole, the measured and simulated values of 2,4-DCP have good fitting effect.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X523
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