Japan Geoscience Union Meeting 2015

Presentation information

International Session (Poster)

Symbol A (Atmospheric and Hydrospheric Sciences) » A-GE Geological & Soil Environment

[A-GE04] Subsurface Mass Transport and Environmental Assessment

Sun. May 24, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Yasushi Mori(Graduate School of Environmental and Life Science, Okayama University), Hirotaka Saito(Department of Ecoregion Science, Tokyo University of Agriculture and Technology), Ken Kawamoto(Graduate School of Science and Engineering, Saitama University), Shoichiro Hamamoto(Department of Biological and Environmental Engineering, The University of Tokyo), Ming Zhang(Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology)

6:15 PM - 7:30 PM

[AGE04-P13] Temperature Dependency on Solute Transport Parameters in Porous Media at Saturated Condition

Moe ARIHARA1, *Shoichiro HAMAMOTO2, Ken KAWAMOTO1, Taku NISHIMURA2, Toshiko KOMATSU1 (1.Graduate School of Science and Engineering, Saitama University, 2.Graduate School of Agriculture and Life Sciences, the University of Tokyo)

Keywords:solute dispersion coefficient, solute diffusion coefficient, hydraulic conductivity, thermal dependency

Widespread use of ground source heat pump systems may disturb thermal condition of soils, and potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to perturbation of subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in repacked columns under temperature control (10 oC to 40 oC) to investigate effects of temperature on solute transport parameters. Toyoura sand and glass beads were used in the experiments. In the transport experiments, 0.01M KCl solution was injected to the core sample with 5-cm diameter and 5-cm height from the bottom end. The concentrations of the electrolyte at the effluent were measured using electrical conductivity, and used for calculating solute dispersion coefficient. The solute diffusion experiments were also performed under different temperature conditions to obtain temperature effect of solute diffusion coefficient. The results showed hydraulic conductivity and solute diffusion coefficient for both materials increased with increasing temperature due to lower viscosity of water at higher temperature. Toyoura sand showed that solute dispersion coefficient at 25 oC was highest followed by 40 oC, and 10 oC, indicating effects of temperature on solute diffusivity and viscosity of water affected solute dispersion characteristics. For glass beads with larger size fraction, temperature dependency on solute dispersion coefficient was insignificant.