Моделиране миграцията на много подвижен замърсител в подповърхностното пространство на индустриални площадки

Abstract

The conditions for spreading of a fast-moving contaminant in the subsurface were studied at an industrial site where large amounts of contaminated water had been discharged over a relatively long period of time. The site is located in the eastern part of the town of Karlovo in Southern Bulgaria. Several hydrogeological units were distinguished in the near-surface following the application of hydrogeological methods and techniques, including investigative drilling, slug tests and laboratory tracer tests. Two-dimensional (2D) mathematical models were used to simulate the mass-transport of a fast-moving contaminant in the unsaturated and saturated zones. A deterministic modelling approach was applied in simulating the established hydrogeological units. Each unit was represented as a two-dimensional object with distinct boundaries and properties. The models were set up using VS2DTI software simulating convective mass transport, reversible elimination (sorption/ desorption), hydrodynamic dispersion, molecular diffusion and mixing. The models were used for predicting the contaminant migration from a continuous source on the surface to a depth of 15-20 m. Different model solutions were used to assess the protective effect of the man-made cover and subsurface geology at the industrial site.