资源环境科技发展态势分析平台

The effect of spatially variable attachment coefficient on biocolloid transport in geochemically heterogeneous porous formations was investigated numerically with a newly developed three-dimensional mathematical model. The biocolloid transport model accounts for horizontal uniform flow in water saturated porous media, and assumes that the biocolloid attachment varies spatially with a constant mean and random fluctuations. Biocolloid particles can either be suspended in the aqueous phase or attached (reversibly or irreversibly) onto the solid matrix. Multiple random realizations of geochemically heterogeneous porous media were employed in order to obtain appropriate ensemble mean concentration distributions, which subsequently were used for classical moment analysis. Emphasis was given in the proper selection of the number of realizations required for the correct ensemble mean estimation of a stochastic variable. The results showed that the existence of spatially variable biocolloid attachment efficiency, caused by geochemical heterogeneity, strongly contributes to an early time substantial increase in biocolloid spreading, an effect that asymptotically dissipated when the migrating biocolloid plume had sampled all of the geochemical heterogeneity within the porous formation. Furthermore, biocolloid plume spreading and enhanced transport were shown to increase with increasing variability of the attachment coefficient. Our findings suggested that neglecting to account for aquifer chemical heterogeneity may lead to erroneous predictions of biocolloid transport in porous media.