MODELS FOR ASSESSING AND PREDICTING THE SUBSURFACE TRANSPORT OF CONTAMINANTS FROM THE WASTEWATER IN THE EFFLUENT CHANNEL OF KCM AD - PLOVDIV, SOUTHERN BULGARIA

Abstract

Until the end of the 20th century, the uncontrolled discharge of highly polluted emissions from the non-ferrous metals companies in Bulgaria was the cause of heavy contamination in vast areas around these industrial sites. In the last two decades, after the introduction of good environmental practices and the closure of polluting industries, a deceleration of the negative processes and a gradual cleaning of the already polluted waters and soils are observed. In order to evaluate and predict these processes, numerical 2D models of the conditions for the subsurface transport of contaminants from the wastewater in the effluent channel of KCM AD-Plovdiv are developed using the VS2DI computer programme. The scheme of convection-diffusion mass-transport is applied, taking into account the concomitant processes of reversible elimination, mechanical dispersion and mixing. Employing the developed models, the fate and transport of pollutants typical for this type of industrial sites – sulphate ions and cadmium (SO4 and Cd) are studied, taking into account their concentration in the wastewater before and after the application of modern technologies and equipment for remediation of contaminated water. The computer simulation encompasses the period from the construction of the effluent channel till 2035.