HR: 1330h
AN: H12A-0961    [PDF]
TI: Calibration and inverse modelling of multicomponent reactive transport in single and dual porosity media
AU: * Samper, J
EM: jsc@iccp.udc.es
AF: Universidad de La Coru¤a, Campus de Elvi¤a s/n, Coru¤a, E-15192 Spain
AU: Fernandez, A
AF: CIEMAT, Av Complutense 22, Madrid, E-28040 Spain
AU: Zheng, L
EM: zheng@iccp.udc.es
AF: Universidad de La Coru¤a, Campus de Elvi¤a s/n, Coru¤a, E-15192 Spain
AU: Montenegro, L
AF: Universidad de La Coru¤a, Campus de Elvi¤a s/n, Coru¤a, E-15192 Spain
AU: Rivas, P
AF: CIEMAT, Av Complutense 22, Madrid, E-28040 Spain
AU: Dai, Z
AF: Wright State University, Dept of geological Sciences, Dayton, OH 45435 United States
AB: The inverse methodology developped by Dai and Samper (2003) is applied to the interpretation of a long-term permeation test performed on a sample of nearly-saturated FEBEX compacted bentonite. Hydrogeochemical modelling of porewaters indicate that the main geochemical processes controlling the chemistry of the bentonite are: acid-base reactions, aqueous complexation, cation exchange, dissolution/ex-solution of CO2 and dissolution and precipitation of highly soluble minerals such as calcite, dolomite, chalcedony and gypsum/anhydrite. All these processes are assumed to take place under equilibrium conditions. The initial saline porewater of the bentonite is flushed with a fresh water with a chemical composition typical of granite formation. Water flux and chemical data of efluent waters were measured during the experiment. Direct and inverse modelling of this experiment has been carried out using the code CORE (Samper et al., 2000). WE address the uncertainties in mobile and immobile porosities as well as on the underlying geochemical conceptual model. Models of chloride breakhrough curves indicate that bentonite exhibits a double porosity behavior. The model reproduces the trends of measured data except for bicarbonate and pH which are affected by uncertainties in the evolution of CO2(g) pressures.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2003 Fall Meeting