地表坡面流通过植被过滤带(VFS)时,植物的茎与枝会把水流的动能转化为湍流的动能,改变地表水的水力特性,进而影响胶体颗粒物的迁移。为了探讨不同水力特性的地表坡面流对胶体在VFS中的迁移和去除机制产生的影响,进而为利用VFS去除胶体污染物的工程设计提供理论依据,通过室内试验,观测不同雷诺数地表坡面中胶体在VFS的迁移过程,同时耦合水量平衡方程与胶体运移方程,构建数值模型模拟胶体在VFS中的迁移。结果表明:随雷诺数增加,绕流状态逐渐复杂、规律性降低,胶体沉积吸附过程加强。同一水力特性条件下,处于不利吸附状态的胶体沿程粒径增大、表面电势减小,使扩散能力和沉积吸附能力减弱。但随雷诺数增加,VFS对胶体的去除效率降低,是由于在土壤饱和状态下流速的增加,胶体向土壤扩散过程减少。
Abstract
When surface flow passes through vegetative filter strips (VFS), the stems and branches of plant will convert the kinetic energy of water flow into turbulent flow energy, change the hydraulic characteristics of the surface flow, and then affect the migration of colloidal particles. The aim of this research is to explore the effect of surface slope flow with different hydraulic characteristics on the migration and removal mechanism of colloid in VFS, and furthermore to provide a theoretical basis for the design of VFS in removing colloidal pollutants. The migration process of colloids in VFS with different Reynolds numbers was observed via indoor experiment, and a numerical model of simulating the colloid migration was constructed by coupling the water balance equation and the colloid migration equation. Results manifested that, as the Reynolds number increased, the flow state complicated, the regularity attenuated, and the colloidal deposition and adsorption process strengthened. Given the same hydraulic characteristics, the particle of colloid in unfavorable adsorption state expanded and the surface potential decreased along the way, which weakened the diffusion capacity and deposition adsorption capacity. However, as the Reynolds number increased, the removal efficiency of colloids by VFS declined due to the increase in flow velocity under soil saturation and the decrease of the diffusion process of colloids into the soil.
关键词
胶体 /
植被过滤带 /
饱和土壤 /
水力特性 /
雷诺数 /
沉积吸附效率系数
Key words
colloidal /
vegetative filter strips /
saturated underlying surface /
hydraulic characteristics /
Reynolds number /
deposition adsorption efficiency coefficient
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 崔 键,马友华,赵艳萍,等. 农业面源污染的特性及防治对策[J]. 中国农学通报,2006, 22(1): 335-335.
[2] 黄 涛. 胶体污染物对多孔介质吸附能力影响机制的微尺度研究[J]. 学术动态, 2012, 33(1): 19-21.
[3] 孙金伟, 许文盛. 河岸植被缓冲带生态功能及其过滤机理的研究进展[J]. 长江科学院院报, 2017, 34(3): 40-44.
[4] 孙棋棋,张春平,于兴修,等. 中国农业面源污染最佳管理措施研究进展[J]. 生态学杂志, 2013, 32(3): 772-778.
[5] 万成炎,马沛明,常剑波,等. 三峡水库生态防护带建设的初步探讨[J]. 长江科学院院报, 2009, 26(1): 9-11.
[6] 庾从蓉, 段佩怡. 植被过滤带的污染物去除效率研究进展[J]. 水资源保护, 2018, 34(2): 68-74.
[7] FLANAGAN K, BRANCHU P, RAMIER D, et al. Evaluation of the Relative Roles of a Vegetative Filter Strip and a Biofiltration Swale in a Treatment Train for Road Runoff[J]. Water Science and Technology, 2017, 75(4): 987-997.
[8] SCAVIA D, KALCIC M, MUENICH R L, et al. Multiple Models Guide Strategies for Agricultural Nutrient Reductions[J]. Frontiers in Ecology and the Environment, 2017, 15(3): 126-132.
[9] YU C,GAO B,MUOZ-CARPENA R,et al. A Laboratory Study of Colloid and Solute Transport in Surface Runoff on Saturated Soil[J].Journal of Hydrology,2011,402(1/2):159-164.
[10]OLILO C, ONYANDO J, MOTURI W, et al. Effect of Vegetated Filter Strips on Transport and Deposition Rates of Escherichia Coli in Overland Flow in the Eastern Escarpments of the Mau Forest, Njoro River Watershed, Kenya[J]. Energy, Ecology and Environment, 2016, 1(3): 157-182.
[11]LAMBRECHTS T, DE BRAEKELEER C, FAUTSCH V, et al. Can Vegetative Filter Strips Efficiently Trap Trace Elements During Water Erosion Events? A Flume Experiment with Contaminated Sediments[J]. Ecological Engineering, 2014, 68: 60-64.
[12]PALMER M R. Observations of Particle Capture on a Cylindrical Collector: Implications for Particle Accumulation and Removal in Aquatic Systems[D]. Cambridge, Massachusetts: Massachusetts Institute of Technology, 2003.
[13]PALMER M R, NEPF H M, PETTERSSON T J R. Observations of Particle Capture on a Cylindrical Collector: Implications for Particle Accumulation and Removal in Aquatic Systems[J]. Limnology and Oceanography, 2004, 49(1): 76-85.
[14]WU L, MUNOZ-CARPENA R, GAO B, et al. Colloid Filtration in Surface Dense Vegetation: Experimental Results and Theoretical Predictions[J]. Environmental Science and Technology, 2014, 48(7): 3883-3890.
[15]PURICH A. The Capture of Suspended Particles by Aquatic Vegetation[D]. Perth: University of Western Australia, 2006: 1-97.
[16]DICKEY E C, VANDERHOLM D H. Vegetative Filter Treatment of Livestock Feedlot Runoff 1[J]. Journal of Environmental Quality, 1981, 10(3): 279-284.
[17]汪健夫. 改性高岭土沉积特性实验与模拟研究[D]. 杭州:浙江大学, 2020.
[18]夏威夷,高新新,赵晓冬,等. 含植被河道水流阻力系数试验研究[J]. 水运工程, 2020, 40(7): 34-40.
[19]赵 芳, MAVROMMATIS A, STAMOU A,等. 刚性淹没球冠状植被水流特性试验研究[J]. 水利学报, 2018, 49(3): 353-361.
[20]WU L, GAO B, MUNOZ-CARPENA R. Experimental Analysis of Colloid Capture by a Cylindrical Collector in Laminar Overland Flow[J]. Environmental Science and Technology, 2011, 45(18): 7777-7784.
[21]WU L,GAO B,MUNOZ-CARPENA R,et al. Single Collector Attachment Efficiency of Colloid Capture by a Cylindrical Collector in Laminar Overland Flow[J]. Environmental Science and Technology,2012,46(16):8878-8886.
[22]MOUTSOPOULOS K N, TSIHRINTZIS V A. Approximate Analytical Solutions of the Forchheimer Equation[J]. Journal of Hydrology, 2005, 309(1): 93-103.
[23]HELMERS M, EISENHAUER D. Overland Flow Modeling in a Vegetative Filter Considering Non-planar Topography and Spatial Variability of Soil Hydraulic Properties and Vegetation Density[J]. Journal of Hydrology, 2006, 328(1/2): 267-282.
[24]LIENHARD J H. Synopsis of Lift, Drag, and Vortex Frequency Data for Rigid Circular Cylinders[M]. Pullman, Washington: Technical Extension Service, Washington State University, 1966.
[25]SHEN C Y,HUANG Y F,LI B G,et al. Predicting Attachment Efficiency of Colloid Deposition under Unfavorable Attachment Conditions[J]. Water Resources Research,2010,46:12,doi:10.1029/2010WR009218, 2010.
[26]YANG C, DABROS T, LI D Q, et al. Kinetics of Particle Transport to a Solid Surface from an Impinging Jet under Surface and External Force Fields[J]. Journal of Colloid and Interface Science, 1998, 208(1): 226-240.
[27]于映雪,张秋兰,崔亚莉,等. 混合钠-钙电解质溶液的物质的量比和胶体粒径对胶体在饱和多孔介质中运移的影响[J]. 环境科学学报, 2018, 38(4): 1474-1481.
基金
国家自然科学基金青年科学基金项目(51509069);国家自然科学基金联合基金项目(U2040209);“一带一路”水与可持续发展科技基金资助项目(202041711)
PDF(1418 KB)
