Press Release
IEG Technologies UK Limited is a specialist company offering a range of revolutionary patented technologies for in situ soil and groundwater remediation.
Underpinned by an extensive track record gained on several hundred remediation projects completed over 15 years across Europe and the USA, IEG's patented
Groundwater Circulation Well™ (GCW™) can in many circumstances be used to achieve clean up
targets quicker, cheaper, more intelligently and sustainably than other more conventional in situ techniques.
Schematic of IEG Groundwater Circulation Well™ System
IEG GCW™ systems are specially designed and configured on a site-specific basis, depending on geoenvironmental and contaminant characteristics, to provide accelerated aerobic,
enhanced anaerobic or sequential anaerobic to aerobic reactions to deliver more effective treatments.
By selectively applying biological, chemical, and physical processes, IEG's soil air and groundwater circulation technologies are applicable for a wide range of contaminants,
including hydrocarbons (gasoline, diesel, kerosene, fuel oils), polycyclic aromatic hydrocarbons (PAH), creosote, chlorinated solvents (trichloroethane, tetrachloroethane), pesticides and nitrates,
ammonia and metals.
For complex problems, GCW™ technology can also be coupled with other IEG in situ process methods such as vacuum liquid recovery, bioaugmentation, bioventing,
soil flushing, soil air circulation and coaxial groundwater circulation/air sparging.
IEG's solutions deliver significant advantages over other in situ remediation methods. They are: -
- Quicker - groundwater circulating through the aquifer enhances the mobilisation of adsorbed and dissolved contaminants by forcing flow through less permeable lenses and drawing
them to the treatment well; in addition, circulation flow accelerates and enhances delivery of oxygen and nutrients to contaminated zones, stimulating natural in situ bioremediation much faster
than other techniques.
- Smaller - compact designs require less space on-site.
- Smarter - in-ground circulation flow contains groundwater plumes and treats contaminants simultaneously in one well - operates as a "Virtual-Permeable Reactive
Barrier™".
- Greener - requires low negative pressure-low energy, delivering maximum treatment efficiency, with minimum waste.
Other benefits offering potential for significant cost and time savings include:-
- Minimal ground excavation and solid waste generation.
- No abstraction of groundwater for above ground treatment - the aquifer is the treatment zone.
- No reinjection wells required - no injection consent.
- No trade effluent discharge - no discharge consent.
- Achieves simultaneous hydraulic containment and physical, chemical and/or biological treatment.
Technical Note
The IEG Groundwater Circulation Well™ (GCW™) system creates an in situ vertical groundwater circulation cell by drawing groundwater from an aquifer formation through one
screen section of a multi-screened well and discharging it through another. The sphere of influence of a GCW™ depends on the distance between the two screen sections and the
thickness of the contaminated aquifer. The larger the circulation cell, the larger is the travel time for the circulation.
According to the required remedial strategy, two modes of operation are possible; standard and reverse flow, where groundwater is circulated around a central GCW™.
Under "standard" flow conditions, groundwater flows upward through the GCW™. In "reverse" circulation mode, the flow of groundwater within the GCW™ is
downward. In the latter case, groundwater in the lower half of the aquifer moves away from the well while water in the upper half of the aquifer moves toward the well. In either case, induced
differences in potentiometric head establish and maintain the three-dimensional circulation cell in an ellipsoidal zone around the circulation well.
The majority of the groundwater captured by the circulation cell circulates a number of times through the GCW™ before being released, treated, down gradient. Due to mass
conservation, the same quantity of groundwater is released by the well down gradient as is captured up gradient.
The vertical and horizontal circulation flow patterns induced by the GCW™ force groundwater to move through the entire aquifer within a defined and calculated circulation cell
thus improving the mobilisation of contaminants by forcing flow through less permeable formation lenses. As such, groundwater serves as an in situ carrier bringing contaminants into the dissolved
phase and transporting them from throughout the capture zone to the GCW™ system for treatment. Clean groundwater is then discharged back into the formation.
Due to its effective means of ensuring hydraulic control and its simultaneous in situ treatmant capability, the GCW™ may be used in sequence to act as a "Virtual-Permeable Reactive
Barrier™" (V-PRB™). If the width of a contaminant plume is larger than the capture zone of a single well, several GCW's may be arranged in a transverse direction to
the natural groundwater flow. The distance between each system can be modelled and calculated to ensure that no groundwater passes the well barrier without being captured and treated.
Unlike conventional PRB's, where a passive permeable barrier is inserted into the aquifer, GCW™ is an active remediation technique because it induces high groundwater
velocities around the well barrier to expedite remediation.
IEG's range of patented in situ systems to treat contaminated soil and groundwater include:
