MOBILIZATION AND LEACHING OF NATURAL AND WATER DISPERSIBLE COLLOIDS IN AGGREGATED VOLCANIC ASH SOIL COLUMNS

SOILS AND FOUNDATIONS

LIS WOLLESEN DE JONGE¹  KEN KAWAMOTO²  PER MOLDRUP³  TOSHIKO KOMATSU²  CHAMINDU DEEPAGODA T.K.K.³  HIROTAKA SAITO⁴ 

[1] Department of Agroecology and Environment, Faculty of Agricultural Sciences, Aarhus University;Graduate School of Science and Engineering, Saitama University;Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University;Department of Ecoregion Science, Tokyo University of Agriculture and Technology

关键词: chemical non-equlibrium;    column experiment;    leaching;    soil colloids;    two-site equilibrium/kinetic model;    volcanic ash soil;    water dispersible colloids;    (IGC: D4/E7);   

DOI  :  10.3208/sandf.51.123

学科分类：建筑学

来源: Japanese Geotechnical Society / Jiban Kogakkai

【 摘 要 】

References(31)Cited-By(1)Colloid-facilitated transport enhances migration of strongly sorbing compounds (e.g., radionuclides, phosphorus, heavy metals) in soil and groundwater. Mobilization, transport and deposition of soil colloids are the underlying processes governing colloid-facilitated contaminant transport. Although significant progress has been made in simulating mobilization and transport/deposition of model colloids in different collector systems, it may be inadequate for the prediction of natural colloidal behavior in the subsurface. This study quantifies the leaching of natural volcanic ash soil colloids (NC) as well as the simultaneous transport of applied water dispersible soil colloids (WDC) in aggregated volcanic ash soil columns. Two water-saturated soil columns were irrigated with artificial irrigation water (AIW) at an intensity of 80 mm/hr for 60 hours. Two additional columns were irrigated at the same intensity, but a colloidal suspension of 5 mg/L was applied after 20 hours for a period of 20 hours. Effluent colloid concentrations were measured in each experiment. HYDRUS-1D was used for the simulation and estimation of colloid transport parameters. The results clearly showed different kinetics for applied colloid transport and natural colloid leaching. Transport of applied WDC followed first-order attachment kinetics, while the two-site equilibrium/kinetic model with equal fractions of equilibrium and kinetic sites best described the leaching of NC. Coupling these best model approaches well predicted the simultaneous leaching of natural and applied colloids, hereby providing a useful tool for the design of colloid-based in-situ soil remediation systems.

【 授权许可】

Unknown