In situ restoration techniques for aquifers contaminated with hazardous wastes

Abstract

Improper disposal of hazardous wastes is a threat to the nation's ground water supply. Methods which prevent contamination are probably the most effective techniques to protect ground water. Once contamination problems occur, there are a number of in situ techniques that can be used to cleanse the ground water and at least partially restore the aquifer. Before any treatment program can be implemented, a thorough investigation of the hydrogeology and contamination problems of the site must be made. Plume management techniques such as barriers to ground water flow or hydrodynamic control can be effective when properly installed. One of the options used frequently is to remove the contaminated material to a secure site; while this cleans up the contaminated site, the material is not treated and the potential for contamination of the second site exists. Chemical and physical treatment techniques include processes such as neutralization, chemical reaction, extraction and immobilization. Biological techniques for in situ treatment generally involve enhancing the degradative capacity of the indigenous microflora or the addition of organisms acclimated to degrade the contaminants. Combinations of chemical and biological processes are often effective. Aquifer restoration is likely to be costly, time-consuming, and often only partially effective.