Horizontal Environmental Well (HEW)
Definition - What does Horizontal Environmental Well (HEW) mean?
A horizontal environmental well (HEW) is installed for cleaning of underground storage tank sites and at environmental cleanup sites.
A HEW can be installed using horizontal directional drilling (HDD) by using entry and exit holes, known as a double-ended well, or by using only an entry hole, known as a blind well. Unlike vertical wells, horizontal wells that are dug horizontally beneath the earth’s surface are able to make contact and draw out contaminants from a greater area.
Horizontal environmental wells are also known as horizontal remediation wells (HRWs)
Trenchlesspedia explains Horizontal Environmental Well (HEW)
A horizontal environmental well (HEW) is advantageous in that it can access places below surface obstructions, reduce number of vertical wellheads that will be otherwise required, have greater contact with the contaminated zone, and reduce the construction time on site.
A single horizontal well can replace a number of vertical wells that will be required for the same area, making it a very economical and time-saving option.
However, HEWs are more expensive to install than vertical wells and also more challenging in its design, drilling, and installation aspects. Commonly used methods to remediate wells are soil vapor extraction (SVE), soil venting, and air sparging.