1.3.1 Introduction

Ask any groundwater professional in the field to list the most common perceptions concerning aquifer restoration and you are likely to get this answer: (1) they are too costly, (2) they are time-consuming, (3) they are not always effective, and (4) pertinent information is usually not available for the aquifer and the geological system. These perceptions, having generally been accepted by groundwater professionals over 2 decades, are slowly changing, however. An ever-increasing amount of information is becoming available about aquifer restorations and groundwater cleanup. More and more information is being shared by aquifer professionals at conferences and meetings. The federal government, however, has taken the lead and has established technology transfer programs and funded site demonstration programs. Indeed, government sponsoring agencies such as the U.S. Air Force Center for Environmental Excellence, U.S. Army Environmental Center (ACE), Federal Remediation Technologies Roundtable, U.S. Environmental Protection Agency (EPA), U.S. Navy (USN), and U.S. Department of Energy (DOE) have shed more light on remediation technologies in the last 8 years than all efforts in the preceding 50 years.

This chapter summarizes the state of the art for aquifer restoration. As previously stated, it focuses on the aqueous groundwater aquifer remedial methods, dense non-aqueous-phased liquids (DNAPLs), and finally light nonaqueous-phase liquids (LNAPLs). It is noted here, as earlier, that both the DNAPLs and LNAPLs pose the most significant threat to groundwater systems, and...