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Using CO_(2)and oxidants for in situ regeneration of permeable reactive barriers for leachate-contaminated groundwater

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Journal of Environmental Sciences 2024年第11期145卷 152-163页

作者： Fangming Xu Xingshen Luo Junlong Huang Yuecen Dong kaixuan zheng Yanting Liu Yanjun Liu Hongtao Wang School of Environment Tsinghua UniversityBeijing 100084China School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China Zhongye Changtian International Engineering Co.Ltd. Changsha 410205China

Groundwater contamination near landfills is commonly caused by leachate leakage,and permeable reactive barriers(PRBs)are widely used for groundwater ***,the deactivation and blockage of the reactive medium in PRBs limit their long-term *** the current study,a new methodology was proposed for the in situ regeneration of PRB to remediate leachate-contaminated ***_(2)coupled with oxidants was applied for the dispersion and regeneration of the fillers;by injecting CO_(2)to disperse the fillers,the permeability of the PRB was increased and the oxidants could flow evenly into the *** results indicate that the optimumfiller proportion was zero-valent iron(ZVI)/zeolites/activated carbon(AC)=3:8:10 and the optimum oxidant proportion was COD/Na_(2)S_(2)O_(8)/H_(2)O_(2)/Fe^(2+)=1:5:6:5;the oxidation system of Fe^(2+)/H_(2)O_(2)/S_(2)O_(8)^(2−)has a high oxidation efficiency and *** average regeneration rate of zeolites was 72.71%,and the average regeneration rate of AC was 68.40%;the permeability of PRB also *** technology is effective for the remediation of landfills in China that have large contaminated areas,an uneven pollutant concentration distribution,and a long pollution *** purification mode of long-term adsorption and short-time in situ oxidation can be applied to the remediation of long-term high-concentration organically polluted groundwater,where pollution sources are difficult to cut off.

关键词： Landfill leachate Groundwater remediation PRB in situ regeneration Advanced oxidation technology

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Passive convergence-permeable reactive barrier (PC-PRB): An effective configuration to enhance hydraulic performance

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Frontiers of Environmental Science & Engineering 2022年第12期16卷 79-88页

作者： kaixuan zheng Xingshen Luo Yiqi Tan Zhonglei Li Hongtao Wang Tan Chen Li Zhao Liangtong Zhan School of Environment Tsinghua UniversityBeijing100084China College of Life and Environmental Sciences Minzu University of ChinaBeijing100081China Institute of Geotechnical Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou310058China

A novel permeable reactive barrier(PRB)configuration,the so-called passive convergence-permeable reactive barrier(PC-PRB),is proposed to overcome several shortcomings of traditional PRB configurations,such as high dependency to site hydrogeological characteristics and plume *** PC-PRB is designed to make the plume converge towards the PRB due to the passive hydraulic decompression-convergent flow *** corresponding passive groundwater convergence(PC)system is deployed upstream of the PRB system,which consists of passive wells,water pipes,and a buffer layer.A two-dimensional(2D)finite-difference hydrodynamic code,entitled PRB-Flow,is developed to examine the hydraulic performance parameters(i.e.,capture width(W)and residence time(t))of *** is proved that the horizontal 2D capture width(Wh)and vertical 2D capture depth(Wv)of the PC-PRB remarkably increase compared to that of the continuous reactive barrier(C-PRB).The aforementioned relative growth values in order are greater than 50%and 25%in this case ***,the PRB geometric dimensions as well as the materials cost required for the same plume treatment *** sensitivity analysis reveals that the dominant factors influencing the hydraulic performance of the PC-PRB are the water pipe length(Lp),PRB length(LPRB),passive well height(Hw),and PRB height(HPRB).The discrepancy between the Wh of PC-PRB and that of the C-PRB(i.e.,∆Wh)has a low correlation with PRB parameters and mainly depends on Lp,which could dramatically simplify the PC-PRB design ***,the proposed PC-PRB exhibits an effective PRB configuration to enhance hydraulic performance.

关键词： Passive convergence-permeable reactive barrier(PC-PRB) Permeable reactive barrier configuration Numerical simulation Hydraulic performance evaluation Sensitivity analysis

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Numerical modeling and performance evaluation of passive convergence-permeable reactive barrier(PC-PRB)

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Frontiers of Environmental Science & Engineering 2023年第11期17卷 131-144页

作者： kaixuan zheng Dong Xie Yiqi Tan Zhenjiang Zhuo Tan Chen Hongtao Wang Ying Yuan Junlong Huang Tianwei Sun Fangming Xu Yuecen Dong Ximing Liang School of Environment Tsinghua UniversityBeijing 100084China College of Life and Environmental Sciences Minzu University of ChinaBeijing 100081China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China

The passive convergence-permeable reactive barrier(PC-PRB)was proposed to address the limitations of traditional PRB *** evaluate the hydraulic and pollutant removal performance of the PC-PRB system,we developed a simulation code named *** code uses the two-dimensional(2D)finite element method to simulate groundwater flow and solute *** studies demonstrate that PC-PRB technology is more efficient and cost-effective than continuous permeable reactive barrier(C-PRB)in treating the same contaminated *** of PC-PRB technology results in a 33.3%and 72.7%reduction in PRB length(L_(PRB))and height(H_(PRB)),respectively,while increasing 2D horizontal and 2D vertical pollutant treatment efficiencies of PRB by 87.8%and 266.8%,*** addition,the PC-PRB technology has the ability to homogenize the pollutant concentration and pollutant flux through the PRB system,which can mitigate the problems arising from uneven distribution of pollutants in the C-PRB to some *** L_(PRB)required for PC-PRB decreases as the water pipe length(L_(p))increases,while the H_(PRB)required initially decreases and then increases with increasing L_(p).The effect of passive well height(Hw)on H_(PRB)is not as significant as that of L_(p)on H_(PRB).Overall,PC-PRB presents a promising and advantageous PRB configuration in the effective treatment of various types of contaminated plumes.

关键词： Passive convergence-permeable reactive barrier Numerical modeling Hydraulic behavior assessment Pollutant treatment performance evaluation Influential factors analysis

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集合卡尔曼滤波方法的高时空分辨率山区地表反照率反演

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遥感学报 2022年第12期26卷 2568-2581页

作者：郑凯旋林兴稳闻建光郝大磊浙江师范大学地理与环境科学学院金华321004 中国科学院空天信息创新研究院遥感科学国家重点实验室北京100094 中国科学院大学北京100049

高分辨率地表反照率遥感产品以其空间分辨率高的优点,目前正成为区域能量平衡和气候变化研究的重要数据源。现行的高分辨率地表反照率遥感反演算法及数据产品均假设地表平坦且均一,缺乏对地表异质性和地形复杂性的考虑,将适用于平坦地... 详细信息

高分辨率地表反照率遥感产品以其空间分辨率高的优点,目前正成为区域能量平衡和气候变化研究的重要数据源。现行的高分辨率地表反照率遥感反演算法及数据产品均假设地表平坦且均一,缺乏对地表异质性和地形复杂性的考虑,将适用于平坦地表的反演算法应用于山区将存在一定的误差。改进的直接算法将直接反演算法与山地辐射传输模型结合,为反演山区高分辨率地表反照率提供了可能,可以反演山区地表反照率产品。但该算法受到下垫面积雪、云污染等影响,反演的影像时域不连续,且存在着较多的缺失值,无法构建时空连续的地表反照率产品来支撑山区地表能量平衡相关研究。针对这一问题,本文以高分四号(GF-4)卫星数据为例,首先基于改进的直接反演算法反演山区高分辨率地表反照率,结合MODIS BRDF/Albedo产品构建先验知识背景场,采用集合卡尔曼滤波方法对反演的山区地表反照率进行时空填补,构建了时空连续的地表反照率反演方法,并生产了2016年—2017年的山区地表反照率产品。研究结果表明,反演的时空连续高分辨率地表反照率产品与地面站点观测数据的一致性较好。不同坡度地面站点的验证结果显示,反演的时空连续地表反照率产品在湿地、农田等平坦地表下RMSE小于0.01,坡度较大的站点下RMSE为0.0163。本文描述的山区地表反照率时空填补技术也可以应用到其他定量遥感产品,为这些产品在山区地表下的填补技术提供有效参考。

关键词：地表反照率山区地表高分四号集合卡尔曼滤波算法长时间序列

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