Nonlocal reactive transport in heterogeneous dual-porosity media with rate-limited sorption and interregional mass diffusion

Authors
Citation
H. Huang et Bx. Hu, Nonlocal reactive transport in heterogeneous dual-porosity media with rate-limited sorption and interregional mass diffusion, WATER RES R, 37(3), 2001, pp. 639-647
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology,"Civil Engineering
Journal title
WATER RESOURCES RESEARCH
ISSN journal
0043-1397 → ACNP
Volume
37
Issue
3
Year of publication
2001
Pages
639 - 647
Database
ISI
SICI code
0043-1397(200103)37:3<639:NRTIHD>2.0.ZU;2-8
Abstract
Huang and Hu [2000] developed a nonlocal, first-order, Eulerian theory for the mean concentration of a conservative tracer in a dual-porosity medium. Here the results of Huang and Hu are extended to reactive chemical transpor t under linear nonequilibrium sorption in both mobile and immobile zones. S imilar to Huang and HM [2000], a two-zone, mobile and immobile, model [van Genuchten and Wierenga, 1976] is adapted to account for the interregional m ass transfer. Hydraulic conductivity in the mobile zone, sorption coefficie nts in both zones, and interregional mass diffusion rate are all assumed to be spatial random variables to account for the inherent spatial variabilit y of physical and chemical properties of a natural medium. The analytical s olution for mean concentration in mobile water is given explicitly in Fouri er-Laplace space and numerically converted to real space via a fast Fourier transform method. The results are simplified to conservative transport in a dual-porosity medium [Huang and Hu, 2000] and reactive transport in a one -zone model [Hu et al., 1995] under appropriate conditions. The solution pr ovides a tool to investigate the validity of an "effective sorption" method , where various chemical sorption and physical mass transfer processes are treated as a sorption process with effective sorption parameters. This stud y shows that chemical sorption and interregional mass diffusion may be lump ed together as an effective sorption process under specific conditions. Gen erally speaking, however, such simplification will lead to a significant er ror in prediction of the plume evolution, especially at late travel time. I t is also shown that randomness of the interregional mass transfer process will significantly enhance the plume spreading and lead to a more negativel y skewed plume.