Environmental Engineering Reference
In-Depth Information
(MCWD, 2008a). The range of detections in Mesa's wells in 2007 was nondetect to 16 μg/L
(MCWD, 2008b). The City of Fountain Valley's wells continue to be tested for 1,4-dioxane; in 2007,
results ranged from nondetect to 6.6 μg/L (City of Fountain Valley, 2008). Blending with water from
uncontaminated wells lowers 1,4-dioxane concentrations such that levels in water delivered to
homes may be below the 3 μg/L California Notii cation Level.
8.6.5 I
NSTITUTIONAL
M
EASURES
TO
P
REVENT
F
UTURE
I
NDUSTRIAL
D
ISCHARGES
A
DVERSE
TO
R
ECYCLING
W
ASTEWATER
In order to ensure that Water Factory 21 is not again subjected to unexpected high inl uent concen-
trations of 1,4-dioxane, the Orange County Sanitation District entered into an agreement with
OCWD to establish a 5 μg/L target concentration for 1,4-dioxane in the wastewater treatment plant
efl uent (i.e., the inl uent to the Water Factory 21 advanced treatment system) (Mowbray, 2008).
OCWD continues to pioneer new advances in the reuse of treated wastewater, the identii cation of
emerging contaminants, and their treatment. USEPA recently awarded OCWD a $300,000 grant to
research the fate of emerging contaminants including 1,4-dioxane in treatments using a variety of
reverse osmosis membranes (Yamachika, 2007).
8.7 AIR FORCE PLANT 44, TUCSON, ARIZONA
William H. DiGuiseppi, AECOM
The Air Force Plant 44 case study rel ects work funded by the United States Air Force (USAF),
through the Air Force Center for Engineering and the Environment (AFCEE). However, the follow-
ing is solely the opinion and assessment of AECOM Environment (formerly Earth Tech, Inc.) and
does not rel ect the opinion or approval of the USAF.
8.7.1 B
ACKGROUND
Air Force Plant (AFP) 44 is located 15 miles southwest of downtown Tucson, Arizona. It is bounded
on the east by Tucson International Airport and on the west by Nogales Highway (Route 89), the
Union Pacii c Tucson-Nogales railroad spur, and the San Xavier Papago Indian Reservation, of the
Tohono O'odham nation. To the south is the Hughes Access Road, vacant land, and light commer-
cial property. AFP 44 covers approximately 1266 acres and has industrial facilities occupying a
total building area in excess of 1.2 million square feet. The government-owned, contractor-operated
defense industrial plant was constructed by Hughes Aircraft Company (Hughes) in 1951 for the
purpose of manufacturing Falcon air-to-air missiles. Hughes sold the plant to the U.S. government
in 1951. Hughes then operated AFP 44 under a series of facility contracts from 1951 to 1997. In
December 1997, Hughes merged with Raytheon Company (Raytheon), which has operated the plant
since that time. AFP 44 has been used for the production of weapons systems since its inception in
1951 (Earth Tech, 1994).
Since 1981, the USAF, in conjunction with Hughes, has investigated soil and groundwater impacts
at AFP 44 under the DOD (U.S. Department of Defense) Installation Restoration Program (IRP).
The Tucson International Airport Area (TIAA) was placed on the preliminary USEPA National
Priorities List (NPL) in July 1982. It was declared a Superfund Site and placed on the i nal NPL list
in September 1992 (Earth Tech, 1994). AFP 44 is one of six project areas within the TIAA Superfund
Site. The USAF is the lead federal agency at AFP 44 and is responsible for environmental response
actions that are being conducted in accordance with CERCLA, as amended. In 1983 and 1984,
additional USAF/Hughes studies dei ned an off-site groundwater TCE plume substantially attribut-
able to AFP 44. The plume encompassed an area containing City of Tucson water supply wells,
several of which were closed following verii cation of solvent impacts through additional sampling.
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