Oil leaks and spills often result in uncontrolled and unintended releases of contaminants in the environment. After addressing the leak and removing released contaminant, the residual oil impacts are often left in place for natural weathering and degradation. These impacts exist in many phases in the subsurface, primarily adsorbed to the soil, dissolved in groundwater and as a free product (light non-aqueous phase liquid (LNAPLs) on groundwater table. These impacts are known to contaminate soil and/or groundwater, and pose risks to human health and the environment. The degree and extent of risk depends on the release quantity, location, exposure pathways and proximity to sensitive receptors.
This presentation discusses our India-based experience and case studies including: a) investigations carried out to define the nature and extents of the contamination and quantify risks posed by the impacts, and b) various remediation technologies employed to clean up sites including bioremediation, chemical oxidation, free-product recovery system, air sparging, soil vapor extraction, and monitored natural attenuation. Monitored natural attenuation and bioremediation are typically considered the most cost-effective methods to remediate oil impacts. The presentation will also discuss the conditions under which typical remediation technologies are cost-effective and beneficial.