44 Groundwater Hydrogeology

Monday, 15 March 2010
1:30 PM - 5:35 PM
International E

INNOVATIVE TECHNOLOGY TO IMPROVE THE PERFORMANCE OF REMEDIATION WELLS

Paper number: 44-11
Program: Technical Sessions
Time: 4:35 PM – 4:55 PM

Authors

Abstract

The lifecycle of a groundwater remediation project usually involves in-situ treatment and/or hydraulic recovery of contaminant mass. Treatment systems typically meet contaminant mass removal expectations during the first several months; however, mass removal decreases over time due to ageing, biological fouling, chemical precipitation, and sediment deposition on and around the well screens. The end result is a high maintenance, contaminant recovery system that operates for many years with little progress toward reaching cleanup goals. An attempt to improve system performance is often made by scaling the system to work harder, including upgrading system components, installing more wells or completely changing the primary technology to an alternative. The condition of the system’s recovery wells are often overlooked as a reason for diminishing system performance.

Conventional methods of well development and maintenance, including chemical and mechanical processes, have had varying levels of success in optimizing contaminant treatment systems. Impulse generation is a highly efficient and cost effective emerging technology option for the rehabilitation of contaminant recovery systems that are not maintaining system performance. The technology involves releasing an inert, compressed gas into the well screen interval in rapid, short bursts. This generates vibrations that loosen sediment and biological deposits on the well screen, surrounding gravel pack and native formation. This technology has proven to be more effective at rehabilitating well screens than conventional methods alone.

Impulse generation methodology has been employed on groundwater remediation projects in New York, New Jersey and Maryland resulting in increases in contaminant recovery and overall treatment system performance. Economic analysis indicates a reduction in contaminant recovery costs per pound following well rehabilitation.