- Bioremediation (Natural Attenuation) – Stimulating indigenous microbial populations in the subsurface to biodegrade organic contaminates.
- Dig and Haul (Excavation and Disposal) – Bulk removals, as well as precision excavation to remove the impacted materials, followed by transportation and disposal.
- Groundwater Systems – Installation of groundwater-soil-vapor recovery systems to remove contaminated groundwater, complete treatment, and dispose of the contaminates and clean water.
- Negative Air Enclosures – Construction of temporary vapor control structures to manage the release of emissions in the work zone and to the surrounding population. Airflow is routed through a blower system and treated before being released. Work is normally performed in Level B personal protective equipment.
- NORM Excavation – Naturally occurring radioactive materials normally have relatively low concentrations of radium; however, some of the materials may contain elevated concentration and must be managed safely to limit human health exposure.
- Radioactive Soils Screening and Sorting – Radionuclides cannot be destroyed or degrade; therefore, the material must be screened and sorted before it can be treated.
- Phytoremediation – A process that uses plants to remove, transfer, stabilize or destroy contaminates in soil, sediment and groundwater.
- Tank Management – Installation and removal of aboveground and underground storage tanks used for bulk storage.
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Case Studies
SOIL REMEDIATION
PIPELINE RELEASE
Maljamar, New Mexico
A hydrocarbon pipeline release occurred over a 5-acre property in a remote area of southeastern New Mexico. Previously, the impacted materials had been excavated and staged in two stockpiles around the site. The north area was an open excavation that was approximately 40 feet in depth and ranged from 150 to 200 feet across.
 Remedial Construction Services, L.P. (RECON) first assisted the Engineer in the collection of soil samples. After receipt of the laboratory report, RECON moved all the material near the excavation. The soil was placed into the excavation based on the amount of hydrocarbons contained in the soil. The less affected material was placed near the bottom of the excavation, while the more affected soils were placed near the top of the excavation during backfilling operations.
From the bottom of the excavation, at 40 feet, to 12 feet below the ground surface, RECON used a Telebelt TM to feed the material into the excavation. The Telebelt TM is a self-contained unit capable of moving materials over 130 feet from point of feed to point of discharge. The machine was selected fro this project for its ability to feed material a great distance, and also is easily relocated around the work in a short time period. Within 12 feet of the surface, the material was placed with a trackhoe and compacted in 1-foot lifts.
The south area was also an open excavation that was approximately 10 feet in depth, and ranged from 60 feet to over 150 feet across. The affected soil stockpiles in this area were also segregated to assist in sampling and used as backfill for the excavation after receipt of the laboratory data. Backfilling and compaction of these soils was accomplished with dozers and trackhoes.
After backfill and compaction of the two areas, RECON was required to conduct site restoration activities. This work included removal of a temporary perimeter fence, re-grading of roads, and grading of surface soils over disturbed areas.
All work was completed in Level D personal protection equipment with special gear for the extremely windy and cold conditions. The project was completed on schedule and within the time frame set by the owner’s engineer.
Guadalupe RESTORATION
Guadalupe, California
 Remedial Construction Services, L.P. (RECON) was awarded this contract by Unocal in December 2005. When Chevron acquired Unocal, the contract became part of our IDIQ contract and is being performed under our Preferred Supplier Contract with Chevron.
Stockpile Removals
This 5-year project began in August 2006, with the mobilization of transportation vehicles and loading equipment. The transportation of soils from the TB8 stockpile began with RECON loading 10 trucks, each 3 times a day. The work has continued on the same transportation schedule and there have been zero complaints from the surrounding community. A total of 500,000 cubic yards of impacted material will be removed from the various stockpiles on the site.
Excavation Activties
In order to excavate an additional 500,000 cubic yards of impacted soils from these highly sensitive coastal dunes, RECON is installing sheetpiling and a dewatering system around each of the excavations before any removal activities begin. This includes the removal of vegetated overburden and clean overburden material.
Using precision excavation techniques, RECON will remove and transport the hydrocarbon impacted materials offsite. Once it is confirmed that all materials of concern have been removed, clean overburden material and onsite borrow material will be used to backfill the excavations. These areas will be closed with the native Coastal Dune Scrub or Wetlands material to restore the area to its original environmentally-friendly habitat.
Safety
Safety is always paramount on a RECON project; we have 38 individuals, including subcontractors, who are committed to maintaining a safe project. These individuals assisted in the creation and use of Job Safety Analyses, participated in the training activities, perform daily and periodically-random safety audits, and follow the 1,200 permit conditions for this site.
The second area to be excavated was located at the bottom of the hill. Groundwater was encountered at 4 feet and the excavation needed to extend an additional 3 feet. In order to avoid dewatering the excavation, the area was divided into grids or “slots”. The first slot was excavated, followed by the third slot. After confirmation samples were verified, the first and third slots were backfilled and the second slot was excavated. This continued until all 33,931 tons of impacted
material was removed. RECON was able to use the groundwater that accumulated in the excavation to assist with the compaction efforts.
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