Steve Strohl and his crew at Universal Drilling in Houston, Texas, recently completed a phytoremediation drilling project under the direction of KMA Environmental and Weston Solutions, Inc.  Phytoremediation is a technique to remediate contaminated soils, water or air by using plants able to contain, degrade or eliminate metals, pesticides, solvents, explosives, crude oil and its derivatives.  A summary of the project follows.  For more information contact Steve Strohl, Universal Drilling, at 800-900-0280.

PHYTOREMEDIATION DRILLING TECHNIQUE

Several rows of fast-growing, water-loving trees are being used to form a hydraulic barrier in a hydrocarbon contaminated groundwater plume at a site near Houston, Texas.  Weston Solutions, Inc. is the managing contractor for the site.  KMA Environmental Services and Universal Drilling Services were contracted to install the phytoremediation system.

A skid-steer equipped with a 12-inch auger was used to advance a boring approximately 1-foot deep for planting the tree.  Universal Drilling Services provided a sonic drill rig, which was used to advance a 2-inch boring from the bottom of the 12-inch hole to the top of the shallow transmissive zone, approximately 10-12 feet below ground surface (bgs).  The 2-inch boring was then backfilled with sand.  The shallow transmissive zone is under confined conditions and the boring allows the groundwater to rise to approximately 3 to 5-feet bgs.  Eucalyptus camaldulensis trees were then planted into the 12-inch hole.  These trees have been planted and monitored at other sites in the area and have shown that a 4-year old tree can “pump” up to 50-gallons of water per day almost year round due to the long growing season in the Houston area.

This planting technique has been used at numerous sites.  The advantages of this technique includes no drill cuttings to dispose of and it is much quicker than using other drilling methods such as hollow stem augers.  Even though this method is quicker, using a standard geo-probe rig allowed for only 50-75 borings per day.  The sonic rig proved to be much quicker with 200 to 250 borings being advanced each day.  The track-mounted rig was also much more maneuverable through the crowded planting area.

It is expected that the trees will tap into groundwater within the first growing season and provide a hydraulic barrier to the off-site migration of the groundwater contaminant plume within 3 to 5 years.

Frank Thomas
KMA Environmental Services
409-599-3384
www.phytofarms.com