Carrier Enhanced Solute Migration in Aquifers

A dissolved solute and carriers are advected by steady random groundwater flow which is modelled by regarding the log-hydraulic conductivity as a stationary random space function (RSF). Our aim consists into analyzing spatial moments pertaining to: i) the dissolved concentration, and ii) the concentration associated to the carrier phase. Both the concentration plumes are supposed to evolve along distinct flow paths which do not interact since the transverse mixing is neglected. Like previous studies (e.g. Cvetkovic & Dagan, 1994), it is seen that the masses and the centres of gravity depend only on the mean velocity field, and chemical processes. We investigate the potential enhancing effect of carriers by comparing spatial moments of the two moving plumes. The forward/reverse mass transfer rates between the liquid and carrier phases combined with degradation coefficients are the critical parameters. In particular, it is shown that potentially most significant effects are obtained when detachment from carrier sites is slow, provided that degradation on carriers is small as compared with the one acting in the liquid phase. Asymptotic results are also presented.