Proven In-situ Remediation Systems
The conventional approach for remediating contaminated groundwater has been to extract the contaminated water, treat it above ground, and reinject or discharge the clean water ("pump-and-treat").
It is becoming increasingly apparent that pump-and-treat technologies require considerable investment over extended periods of time, and that they have been proven inadequate in many cases. Often, they do not actually clean up the source of groundwater contamination. In situ treatment technologies for contaminated groundwater are now considered to be fundamentally more efficient, cost effective and are significantly more sustainable alternatives to pump-and-treat.
GCWs can be used in conjunction with other in situ technologies to treat halogenated VOCs, semi-VOCs (SVOCs), pesticides, and petroleum products and their constituents such as benzene, toluene, ethyl benzene, and xylene (BTEX). They have been applied to a wide range of soil types, from fine silty clay to coarse sandy gravel. With at least two screen sections, GCWs are universally applicable remediation tools.
They can be employed in several configurations, such as in well stripping (IWS), bioaugmentation, enhanced natural attenuation adding nutrients and/or electron acceptors for stimulating bioremediation processes, bioventing, soil vapour extraction, reactive nanoparticle dehalogenation, in situ denitrification and chemical oxidation (ISCO) or reduction (ISCR). They may also be combined with a LNAPL /DNAPL recovery system in the aquifer.
Different GCW configuration and/or composition allows wide and versatile solutions, e.g. the vPRB (in situ Virtual Permeable Reactive Barrier) where several vertical circulation wells are arranged in one line perpendicular to the natural groundwater flow to obtain a curtain of overlapped circulation cells; such configuration could be promising to treat huge plumes generated by contaminated mega-sites.
Groundwater Circulation Well systems are designed to create in situ vertical groundwater circulation cells by drawing groundwater from an aquifer through one screen section of a double-screened well, and discharging it through the second screen section.The pressure gradient between two hydraulically separated screen sections in the well induces a circulation flow in the aquifer. Groundwater circulation commonly occurs from the top of the formation to the bottom (herein termed "standard flow"). Under standard flow conditions, groundwater is pumped upward inside the remediation well as it enters a lower screen section and exits via an upper screen section. The groundwater moves through the treatment zone both horizontally and vertically before entering the influent screen.
In a reverse circulation mode, the flow of groundwater within the GCW well is downward via the aid of an in-well groundwater pump (i.e., water flows from the bottom of the aquifer formation in a torroidal upward pattern). In the reverse circulation mode, water in the lower half of the aquifer moves away from the well while water in the upper half of the aquifer moves towards the well.
GCW Standard-Flow GCW Reverse-Flow GCW Extraction GCW Reinfiltration