The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay,linear sorption,and zero-order...The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay,linear sorption,and zero-order production.The library is constructed using Green's function method(GFM)in combination with available solutions.The library covers a wide range of solutions for various conditions.The aquifer can be vertically finite,semi-infinitive or infinitive,and laterally semi-infinitive or infinitive.The geometry of the sources can be of point,line,plane or volumetric body;and the source release can be continuous,instantaneous,or by following a given function over time.Dimensionless forms of the solutions are also proposed.A computer code FlowCAS is developed to calculate the solutions.Calculated results demonstrate the correctness of the presented solutions.The library is widely applicable to solve contaminant transport problems of one-or multiple-dimensions in uniform flow fields.展开更多
The immobilization of co-contaminants of organic and inorganic pollutants by biochar is an efficient remediation strategy. However, the effect of biochar amendments on the bioaccessibility of the co-contaminants in dr...The immobilization of co-contaminants of organic and inorganic pollutants by biochar is an efficient remediation strategy. However, the effect of biochar amendments on the bioaccessibility of the co-contaminants in dry versus flooded soils has rarely been compared. In batch experiments, bamboo-derived biochar（BB） had a higher sorption capacity for phenanthrene（Phe）/pyrene（Pyr）/zinc（Zn） than corn straw-derived biochar（CB）, while CB had a higher sorption capacity for lead（Pb） than BB. After 150 days of incubation, the amendments of 2% CB, 0.5% BB and 2% BB effectively suppressed the dissipation and reduced the bioaccessibility of Phe/Pyr by 15.65%/18.02%, 17.07%/18.31%and 25.43%/27.11%, respectively, in the aerobic soils. This effectiveness was more significant than that in the anaerobic soils. The accessible Zn/Pb concentrations were also significantly lower in the aerobic soils than in the anaerobic soils, regardless of treatments.The Gram-negative bacterial biomass and the Shannon–Weaver index in the aerobic soil amended with 2% CB were the highest. The soil microbial community structure was jointly affected by changes in the bioaccessibility of the co-contaminants and the soil physiochemical properties caused by biochar amendments under the two conditions. Therefore, dry land farming may be more reliable than paddy soil cultivation at reducing the bioaccessibility of Phe/Pyr/Zn/Pb and enhancing the soil microbial diversity in the short term.展开更多
基金This research was supported by National Scientific Supporting Plan of China(Grand No.2006BAC06B05).
文摘The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay,linear sorption,and zero-order production.The library is constructed using Green's function method(GFM)in combination with available solutions.The library covers a wide range of solutions for various conditions.The aquifer can be vertically finite,semi-infinitive or infinitive,and laterally semi-infinitive or infinitive.The geometry of the sources can be of point,line,plane or volumetric body;and the source release can be continuous,instantaneous,or by following a given function over time.Dimensionless forms of the solutions are also proposed.A computer code FlowCAS is developed to calculate the solutions.Calculated results demonstrate the correctness of the presented solutions.The library is widely applicable to solve contaminant transport problems of one-or multiple-dimensions in uniform flow fields.
基金supported by the National Key Basic Research Program of China(No.2014CB441105)the National Natural Science Foundation of China(No.41671236)+1 种基金the“135”Plan and Frontiers Program of the Institute of Soil Science,Chinese Academy of Sciences(No.ISSASIP1614)the Outstanding Youth Fund of Natural Science Foundation of Jiangsu,China(No.BK20150050)
文摘The immobilization of co-contaminants of organic and inorganic pollutants by biochar is an efficient remediation strategy. However, the effect of biochar amendments on the bioaccessibility of the co-contaminants in dry versus flooded soils has rarely been compared. In batch experiments, bamboo-derived biochar（BB） had a higher sorption capacity for phenanthrene（Phe）/pyrene（Pyr）/zinc（Zn） than corn straw-derived biochar（CB）, while CB had a higher sorption capacity for lead（Pb） than BB. After 150 days of incubation, the amendments of 2% CB, 0.5% BB and 2% BB effectively suppressed the dissipation and reduced the bioaccessibility of Phe/Pyr by 15.65%/18.02%, 17.07%/18.31%and 25.43%/27.11%, respectively, in the aerobic soils. This effectiveness was more significant than that in the anaerobic soils. The accessible Zn/Pb concentrations were also significantly lower in the aerobic soils than in the anaerobic soils, regardless of treatments.The Gram-negative bacterial biomass and the Shannon–Weaver index in the aerobic soil amended with 2% CB were the highest. The soil microbial community structure was jointly affected by changes in the bioaccessibility of the co-contaminants and the soil physiochemical properties caused by biochar amendments under the two conditions. Therefore, dry land farming may be more reliable than paddy soil cultivation at reducing the bioaccessibility of Phe/Pyr/Zn/Pb and enhancing the soil microbial diversity in the short term.
