Solute Dispersion of Organic Compounds on Undisturbed Soil Columns

Abstract

Results of column tests performed on large undisturbed samples are presented, focusing on the behavior of the hydrodynamic dispersion coefficient ($$D_h$$). Tests were performed employing petroleum produced water from onshore facilities percolating sandy soils with different fine contents. To measure the organic content of the produced water, this work used the parameter TPH (total petroleum hydrocarbons). The obtained results show that the longitudinal dispersion coefficient ($$\alpha _L$$) varies with flow velocity ($$v_s$$) and that both the ratio between the hydrodynamic dispersion and diffusion coefficients ($$D_h/D$$) and $$\alpha _L$$ are approximately two orders of magnitude higher than the values normally found in the literature for the same type of soil. This is probably related to the fact that the organic compounds measured by TPH in the produced water are partially in dissolved form, but dispersed particles are also transported by water flow, increasing the experimental values of $$D_h$$.