Method of rapid purging of contaminants from a contaminated area of soil

Abstract

A remediation method for decontamination of soil and groundwater that puts maximum remediation stress on the entire area and volume of contamination. This results in site restoration in days and weeks. The target contaminants are organic compounds such as hydrocarbon constituents associated with diesel fuel, gasoline, kerosene, solvents and creosote. Cleanup concentrations to non-detectable levels can be achieved when properly implemented. Positive pressure is used to push an uncontaminated gas throughout the entire contaminated area/volume. When contacting the contaminated area, volume and media, this gas becomes a carrier gas, stripping the contaminants and carrying them to ground level where they can be collected and treated or dissipated to the atmosphere. The method incorporates air entry points (vertical, horizontal, or directional) installed to a depth below the contamination, combined with a predetermined air entry point spacing (depth/spacing ratio). Use of an operating duty cycle enhances contaminant yield from the groundwater, the soil matrix below the groundwater table, and the soil above the groundwater table. Horizontal migration of contaminants during the process is prevented by the use of gas entry points around a boundary perimeter of the zone being purged. One or two days' use of the method produces the same results as one year of other remediation methods, such as 'pump and treat'. Transfer or removal rates of 40% to 50% per day of the existing contaminants are normal. No (vacuum) extraction wells are necessary to make this in-situ method work. Biodegradation is not a factor. Progress is measured by the amount of contaminants remaining. Site rehabilitation to regulatory standards, measured in micrograms per liter or parts per billion, can be achieved within weeks.