The Sustainability Imperative - Sustainable Design: The Science of Sustainability and Green Engineering - page 250

usage is 1 part per million (ppm). EPA's examples of high-occupancy areas
include residences, schools, and day care centers. The plan is an example of a
targeted and precautionary design, since these areas are likely to have greater
exposures than those at a landfill, which limits contact and access, and because
the cleanup target is five times lower than the EPA requirement. * The removal
of PCBs from the soil will eliminate further regulation of the site and permit
flexible uses of the site after clean up.
A public bid opening was held on December 22, 2000 for the site detox-
ification contract. The IT Group, with a bid of $ 13.5 million, was the low
bidder. Existing funds were sufficient to fund phase I. A contract was entered
into with the IT Group, and a notice to proceed was issued on March 12,
2001. Site preparation work was completed in December 2001. Work in-
cluded the construction of concrete pads and a steel shelter for the processing
area, the extension of county water, an upgrade of electrical utilities, and the
establishment of sediment and erosion control measures.
The treatment equipment was delivered in May 2002. An open house was
held on site the next month so that community members could view the site
and equipment before startup. Initial tests with contaminated soil started at the
end of August 2002. The EPA demonstration test was performed in January
2003. An interim operations permit was granted in March 2003 based on the
demonstration test results. Soil treatment was completed in October 2003. A
total of 81,600 tons of material was treated from the landfill site. The treated
materials included the original contaminated roadside soil and soil adjacent
to the roadside material in the landfill that had been cross-contaminated. The
original plan specified using the BCD process to destroy the PCBs after thermal
desorption separated them from the soil. With only limited data available to
estimate the quantity of liquid PCBs that would be collected, conservative
estimates were used to design the BCD reactor. In practice, the quantity of
PCBs recovered as liquid was much less than anticipated. Thus, the BCD
reactor tanks were too large to be used for the three-run demonstration test
required under TSCA to approve the BCD process. As an alternative, one tank-
load of liquid containing PCBs was shipped to an EPA-permitted facility for
destruction by incineration. Most of the equipment was decontaminated and
demobilized from the site by the end of 2003. Site restoration was completed
in the spring when vegetation became established. The total cost of the project
was $ 17.1 million.
* Similar protective approaches have been used frequently in emergency response and remedial
efforts, such as those that followed the attacks on the World Trade Center towers. For example,
the risk assessments assumed long-term exposures (e.g., 30 years) to contaminants released by
the fire and fugitive dust emissions, even though the exposures were significantly shorter.