Modelling of Soil Contamination and its Remediation by In-Situ Solvent Flushing

Abstract

The consequence of industrialization and other development activities have led to serious degradation of land and water quality. Its remediation has become an important necessity in this scenario. To overcome this issue, it is essential to understand the nature of contaminant transport and their adsorption and desorption substance characteristics. In this study, both organic and inorganic contaminants have been considered, and their movement through the soil together with adsorption and desorption characteristics as well as chemical/biochemical degradation has been investigated. The transport has been described using a set of equations numerically solved with different boundary conditions to represent several scenarios experienced in several cases in the arid environment. The modelling has been confined to one dimension assuming the soil is homogeneous. Contaminant transport may be visualised in many ways; however, in this study, two specific cases are considered. First case is the movement of leachate from soil waste dumping to ground, where toxic organic and inorganic chemicals were also dumped. The second case is the large-scale spillage of some toxic chemicals/oil/chlorinated solvents/non-chlorinated solvents on the soil and their subsequent movement through the soil. There can be several variations of these scenarios. In this chapter, variation with respect to rainfall in the area followed by dry seasons is considered. There is no single technique universally applicable for all contaminated sites. This chapter presents an analysis of the site restoration techniques that may be employed in a variety of contaminated site cleanup programmes.