GROUNDWATER AND LEACHATE: IN-SITU CHEMICAL/PHYSICAL TREATMENT
Directional Wells
Typical Diagram of In Situ Air Stripping with Horizontal Wells
Drilling techniques are used to position wells horizontally (or at an angle) to reach much deeper contaminants (not accessible by direct vertical drilling).
- It may be used to enhance other in-situ processes (e.g. ground water pumping, bioventing, SVE and in-well air stripping).
- Hydraulically activated thrust equipment is used to push the directional boring heads into the earth.
- The machinery & slowly rotating boring head are capable of initiating a borehole, steering down to a desired horizontal depth, then steering to travel along at that depth until downrange of the contaminant.
Uses:
- Treats all contaminant groups.
- Particularly useful if existing structures interfere with placement of vertical wells.
Limitations:
- The potential exists for the wells to collapse.
- Specialist equipment is required.
- Wells are difficult to position precisely.
- Installation of horizontal wells is typically costly.
- Currently, the technology is limited to depths < 12m & horizontal extent of 174m.