Horizontal AS/SVE System in Atlanta
Urban setting for HDD activities. (note drill rig and equipment set in the background)
Finishing the 1st quarter 2014, DTD installed 7 horizontal remediation wells in 10 days, within the city limits of Atlanta, GA. Three of the wells will be used for air sparging (AS), while the remaining four will be used for soil vapor extraction (SVE).
This horizontal well network will be used to speed the remediation of a contamination plume created by various releases from a former gas station. The former gas station has been torn down and single building erected, which is now occupied by a real estate business and a dry cleaner. An ATM is also located on the property which contributed to the already high volume of foot and vehicle traffic. The existing vertical remediation system is not reaching the cleanup goals fast enough, and the increased contact with the contaminant by the horizontal screen is expected to accelerate cleanup.
Drill Rig setup with utility trench.
One priority with this residential/commercial setting was disturbance to the surrounding community. The project team set fencing with privacy screens and worked an adjusted schedule to minimize any disturbance to the local neighborhood. System design required bore paths to pass underneath these high traffic areas and operating businesses.
We used our Vermeer 24x40a drill rig and a 750 gallon single phase mud system to install the wells. Site restrictions required a small equipment footprint and drill rig capable of a sharp bend radius to miss multiple utilities and a short horizontal offset was needed to achieve the desired screen depths. Prior to entering the ground, a local utility contractor exposed multiple utilities with an air knife system. The air knife uses high pressure air to break apart the soil and expose the individual lines. System design required bore paths to pass underneath the various utilities, building footprint and the high traffic areas of the operating businesses.
Utility locating with an air knife tool.
DTD completed over 1,450′ of drilling (7 individual wells) on this project with screen lengths ranging from 80′ to 150′. Even though drilling an AS/SVE remediation system is a typical DTD installation, successful completion was attributed to detailed utility inspections and site organization. DTD demobilized from location after 10 days of site work, complete restoration of the drilling areas, and with minimal impacts to any of the neighboring businesses.