Tailing of the breakthrough curve in aquifer contaminant transport: Equivalent longitudinal macrodispersivity and occurrence of anomalous transport
2008 (English)Conference paper (Refereed)
We analyse the mass arrival (breakthrough curve) at control planes at × of a plume of conservative solute injected at time t = 0 in the plane × = 0. The formation is of random three-dimensional stationary and isotropic conductivity K, characterized by the univariate normal distribution f(Y), Y = lnK, and the integral scale I. The flow is uniform in the mean, of velocity U, and longitudinal transport is quantified by f(z,x), the probability density function (pdf) of travel time r at x. We characterize transport by an equivalent longitudinal macrodispersivity αL(x), which is proportional to the variance of the travel time. If αL is constant, transport is coined as Fickian, while it is anomalous if αL increases indefinitely with x. If f(z,x) is normal (for × I), transport is coined as Gaussian and the mean concentration satisfies an ADE with constant coefficients. For the subordinate structural model transport is anomalous, in spite of the closeness of the conductivity distribution to the lognormal one. To further analyse anomalous behaviour, a relationship is established between the shape of f(K) for K→0 and the behaviour of αL, arriving at criteria for normal or anomalous transport. The model is used in order to compare results with the recent ones presented in the literature, which are based on the Continuous Time Random Walk (CTRW) approach. It is found that a class of anomalous transport cases proposed by CTRW methodology cannot be supported by a conductivity structure of finite integral scale.
Place, publisher, year, edition, pages
2008. no 324, 342-347 p.
, IAHS-AISH Publication, ISSN 0144-7815
Contaminant transport, Groundwater hydrology, Random media, Stochastic processes, Anomalous transports, Break through curves, Conductivity distributions, Conductivity structures, Constant coefficients, Continuous time random walk approaches, Control planes, Gaussian, Log normals, Mean concentrations, Probability densities, Structural models, Travel time, Univariate, Aquifers, Groundwater resources, Hydrogeology, Model structures, Normal distribution, Probability density function, Random processes, Three dimensional, Underground reservoirs, Water quality, Groundwater pollution, aquifer pollution, Gaussian method, groundwater, hydrology, pollutant transport, stochasticity, tailings
Oceanography, Hydrology, Water Resources Water Engineering
IdentifiersURN: urn:nbn:se:kth:diva-154090ScopusID: 2-s2.0-62949233347ISBN: 9781901502794OAI: oai:DiVA.org:kth-154090DiVA: diva2:760084
Groundwater Quality 2007 Conference - Securing Groundwater Quality in Urban and Industrial Environments, GQ'07; Fremantle, WA; Australia; 2 December 2008 through 7 December 2008
QC 201411032014-11-032014-10-142014-11-03Bibliographically approved