Minimizing Trenching using HDD at a Houston Superfund Site
DTD has finished installing a total of 21 conveyance lines at an active Superfund site in Houston, Texas. The source of the site contamination derives from a dry cleaning facility that operated from 1988 until 2003. A new business now occupies the space but the source of the contamination still remains below the parking lot of the shopping center.
Two sources of contaminated soil vapor have been identified and mitigation of the contaminant is currently in progress. In order to remediate the two vapor zones (one shallow, one deep), a total of 21 vertical soil vapor extraction (SVE) wells are being installed within the front parking lot of the shopping center. All the wells will then be connected to a treatment compound via underground conveyance lines. The treatment compound will be located away from the public eye on the back side of the shopping center.
To avoid extensive trenching around the building DTD mobilized to the site to install two 12” HDPE carrier casings connecting the front and back side of the shopping center, or the well locations and the treatment compound. The drilling was completed using one of our Vermeer 24×40’s and a Kemtron mud recycling system. The two bores were drilled beneath the active business then were reamed to 18” diameter before pulling in the 210’ long sections of 12” carrier casings. Lastly the two bundles of one- and two-inch sized conveyance piping were pulled through the 12” casings. The project was completed with 11 days of site activities which included all in house fusing and handling of the 12” HDPE pipe.
Conveyance Lines on back side of Shopping Center (treatment compound location)
Conveyance Lines on front side of Shopping Center (parking lot/vertical SVE well location)
Many HDD contractors may have the ability to complete a project like this but very few have the experience and qualifications to work on contaminated sites. DTD specializes in horizontal well installations across the country that requires us to maintain a stringent health and safety program. All DTD employees are up to date on OSHA HAZWOPER training and annual medical monitoring. We are able to supply the environmental consultant with all required submittals needed to get field work started quickly and without hassle.