Subsequently, in 2005-2006, AMPAC installed an in situ (in place) bioremediation (ISB) perchlorate in groundwater treatment system in the area southeast of Sam Boyd Stadium (Las Vegas, NV) to treat groundwater containing perchlorate at a location approximately one mile up-gradient of Las Vegas Wash. It was comprised of nine shallow (less than 60 ft. below ground surface) groundwater extraction wells east of Boulder Highway, a water conditioning operation on a 1.77 acre City of Henderson site now owned by AMPAC, a re-injection system comprised of re injection wells and a deep re injection trench (treatment occurred in the ground subsequent to the re injection), and approximately 20,000 ft. of underground lines.
The system was started in mid-2006 and was shut down on June 19, 2012 to allow for expansion of perchlorate in groundwater. The following
are performance data for the ISB system's six year run:
- 479,000,000 gallons (1,466 acre-feet) of groundwater treated.
- 56,000 lbs of perchlorate eliminated from that groundwater subsequent to re injection.
- An ability to treat up to 1,152,000 gallons (3.5 acre-feet) of groundwater per day.
- An ability to chemically reduce more than 1,000 lbs of perchlorate (as needed) per day.
- Five new groundwater extraction wells closer to the former manufacturing facility that will extract groundwater at 180-230 ft. below ground surface at a combined rate of approximately 450 gpm. Combined with the existing extraction wells, there will be a total of fourteen extraction wells available for use.
- A new 21,000 ft. underground pipeline to move extracted groundwater from the five new groundwater extraction wells to the FBR treatment location.
- Two first stage 23,000 gallon fluidized bed reactors utilizing sand media.
- One second stage 19,500 gallon fluidized bed reactor utilizing carbon media.
- One 10,000 gallon underground storage tank for ethanol, which is the "electron donor" in the process.
- One 17,000 gallon media separation vessel.
- One 11,400 gallon aeration tank, 9 ft. diameter by 24 ft. tall.
- Other process equipment including water storage tanks, fluidization and other pumps, blowers, biofilters and equipment necessary for solids separation (if needed).
New groundwater modeling completed by AMPAC's consultants in 2009, with peer review by the Nevada Division of Environmental Protection,
resulted in a determination that groundwater closer to the former production facility is moving at a lower depth (150 ft. - 230 ft. below
ground surface) at a much slower pace than estimated previously. One of the consequences of this analysis was the conclusion that if only
the existing in situ system was maintained, the total project time would be increased significantly to more than 60 years. Therefore it was
determined that an expansion of capacity of the system that included direct extraction of groundwater in the area closer to the former
production facility was warranted in order to reduce the total time of operation. The work to achieve the system expansion commenced in
2010. The new larger capacity system will also be a bioremediation process but will be an ex situ (or above ground) Fluidized Bed Reactor
(FBR) located on the 1.77 acre property where water conditioning took place in the in situ process. The system will chemically reduce the same
target electron acceptors (perchlorate, nitrate and chlorate) as in the in situ system that operated for six years. The system will be
operational in 2012 and will have the following characteristics:
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