水平流人工湿地水力学特征与数学模拟

发布时间：2018-03-15 11:50

本文选题：水平流人工湿地　切入点：水力学　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：人工湿地系统作为一种生物污水处理技术,具有易建设、低能耗、运行维护简便、生态效益好等优点,在世界各地得到了广泛应用。本课题主要针对水平流人工湿地,通过自建实验室水平潜流式人工湿地小试系统进行原位实时监测,从水力学角度研究不同水力条件对湿地系统水力学规律和处理效果的影响,并进一步建立数学模型,模拟分析水平流人工湿地的水力学行为和污染物迁移转化规律。主要研究结果如下：1.水平流人工湿地填料性质：通过进行水力学参数测试,得出了六种填料在水平流人工湿地内的最佳填充顺序由表层到底层依次是：黄沙,细彩砂,细黄岩砂,粗黄岩砂,粗彩砂和雨花石。填料的孔隙率均在40%左右,且渗透系数较大,渗透性能良好。2.不同水力条件对人工湿地系统水力学和处理效果的影响：(1)湿地系统的水量损失比随进水流速的增大而减小,当湿地系统的进水流速在13.5 mL/min-332 mL/min之间时,水量损失量为0.6%～6.9%；(2)出水口位置的变化对水平流人工湿地的水力学行为有影响,当出水口位于湿地系统上层时回收率提高2.8%,λ提高0.194,S下降0.261,减少了短流、死区等现象,有效的提高了湿地系统的水力效率；(3)延长水平流人工湿地的水力停留时间有利于提高湿地系统的水力效率,当水力停留时间为73 h时,系统的回收率为98.8,λ为1.048,S为0.447；(4)当水平流人工湿地系统上层进水、上层出水,水力停留时间73 h,水力负荷0.065m3/(m2·d),系统的COD平均去除率为76.4%,硝酸盐氮平均去除率为92.1%,总氮平均去除率为81.1%,总磷平均去除率为50.9%。污染物的去除量主要集中于水平流人工湿地系统的前半部分,并且去除效率随污水在系统中推流距离的延长呈减缓趋势。3.水平流人工湿地的水力学行为和污染物迁移转化规律模拟：应用Visual MODFLOW软件采用试验得到的模型参数对实验室水平流人工湿地系统的水力学行为进行模拟,模型可信度较高；模型反映出人工湿地内部的水流规律,展现出污染物的迁移转化趋势；对不同水力负荷下人工湿地系统进行模拟,模拟结果表明降低人工湿地的水力负荷、延长水力停留时间可以有效提高污染物的去除效果。
[Abstract]:As a biological wastewater treatment technology, artificial wetland system has been widely used in the world because of its advantages of easy construction, low energy consumption, simple operation and maintenance and good ecological benefit. In situ real-time monitoring was carried out through a laboratory horizontal subsurface flow constructed wetland small scale test system. The effect of different hydraulic conditions on the hydraulic law and treatment effect of wetland system was studied from the point of view of hydraulics, and the mathematical model was further established. The hydraulic behavior of horizontal flow constructed wetland and the law of pollutant migration and transformation are simulated and analyzed. The main results are as follows: 1. The filling properties of horizontal flow constructed wetland. It is concluded that the best filling sequence of six fillers in horizontal flow constructed wetland is: yellow sand, fine colored sand, fine Huang Yan sand, coarse Huang Yan sand, coarse colored sand and rain flower stone. The porosity of packing is about 40%, and the best filling order is: yellow sand, fine color sand, fine Huang Yan sand, coarse Huang Yan sand, coarse color sand and rain flower stone. And the permeability coefficient is large, permeability is good. 2. The effect of different hydraulic conditions on hydraulic mechanics and treatment effect of constructed wetland system. The water loss ratio of wetland system decreases with the increase of influent velocity. When the influent velocity of the wetland system is between 13.5 mL/min-332 mL/min, the loss of water is 0.669 / 2) the hydraulic behavior of the horizontal flow constructed wetland is affected by the change of the outlet position. When the outlet is located in the upper layer of the wetland system, the recovery rate is increased by 2.8 and 位 is increased by 0.194N, which decreases by 0.261, and reduces the phenomena of short flow and dead zone, etc. Increasing the hydraulic retention time of horizontal flow constructed wetland is beneficial to improve the hydraulic efficiency of wetland system, when the HRT is 73 h, The recovery rate of the system is 98.8, 位 = 1.048, S = 0.447 ~ 4). When the upper layer of the horizontal flow constructed wetland system enters the water, the upper layer of the constructed wetland system leaves the water. The average removal rate of COD, nitrate nitrogen, total nitrogen removal rate, total nitrogen removal rate, total phosphorus removal rate and total phosphorus removal rate of the system were 76.4, 92.1, 81.1 and 50.9, respectively. The first half of the wetland system, And the removal efficiency is slowing down with the extension of the push distance of sewage in the system. 3. Simulation of hydraulic behavior and pollutant transfer and transformation of horizontal flow constructed wetland: the model parameters obtained by using Visual MODFLOW software are compared with each other. The hydraulics behavior of the horizontal flow constructed wetland system in laboratory is simulated. The model has high reliability; the model reflects the internal flow law of constructed wetland and shows the trend of pollutant migration and transformation; the simulation results of artificial wetland system under different hydraulic loads show that the hydraulic load of constructed wetland is reduced. Prolonging HRT can effectively improve the removal efficiency of pollutants.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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