EP 1110-1-19
30 Jun 01
4-4. Construction Activities. This section should provide a step-by-step description of the
activities undertaken to construct and implement the RA (e.g., mobilization and site preparatory
work; construction of the treatment system; associated site work, such as fencing and surface
water collection and control; system operation and monitoring; and sampling activities). If a
treatment technology was used, reference should be made to the appropriate appendix that
reports factors affecting cost and performance of the system (e.g., site conditions, matrix
characteristics, and operating parameters). An example construction activities section is
provided in Exhibit 4-4.
Exhibit 4-4
Example Construction Activities (Section 3)
Site Preparation
Site preparation activities included clearing, grubbing, and grading the land where the land treatment area
was to be constructed; building a drainage swale around the land treatment area; preparing a temporary,
central soil stockpile area consisting of several lined cells; and installing a perimeter fence with signs
warning against exposure to hazardous material. Approximately four acres were cleared. An estimated 200
cubic yards of contaminated soil found to contain less than 5,000 mg/kg TCICs were excavated during the
site preparation activities and stored in the central stockpile area along with previously excavated,
contaminated soil.
Off-Site Disposal of the Solidified, Operable Unit 1 Waste
To dispose of the 7,500 cubic yards of solidified OU 1 waste, a suitable receiving facility in Emelle,
Alabama, operated by Chemical Waste Management, Inc. (CWM), was identified. The waste was shipped
off-site to the facility in Emelle on December 1, 1996.
Construction of the Land Treatment System
A clay layer ranging from one to three feet in thickness was installed throughout the four-acre land treatment
area. The clay was taken from a borrow pit located elsewhere on the site. The borrow pit was shaped and
used as a 750,000-gallon retention pond for collecting water and leachate from the land treatment area.
Compacted clay berms were placed around the land treatment area and around the soil stockpile area. Swales
were installed outside the treatment area to intercept and redirect run-on.
The land treatment area was prepared with a one percent slope to the northwest corner, where the subsurface
drainage system drained under the berm into a gravel-lined swale that led to the retention pond. The
drainage system consisted of 12-inch-wide, flat, perforated pipe laterals, spaced every 50 feet in an east-to-
west direction. The pipes connected to a south-to-north drainage trench containing cylindrical, perforated
piping sloping to a sump in the northwest corner of the land treatment area. The entire subsurface drainage
system was covered with a minimum of six inches of clean, sorted sand. Finally, a portable irrigation
system, delivering water at 0.5 inches per hour to an area 70 feet in diameter, was installed at the retention
pond, which recirculated the collected water and sprayed the water over the land treatment area.
System Operation
Land treatment was performed in three lifts, with a total of 8,100 yd3 of soil treated: 3,300 yd3 (Lift 1); 3,000
yd3 (Lift 2); and 1,800 yd3 (Lift 3). For site management and sampling purposes, the land treatment area was
divided into eight half-acre, rectangular subplots. A composite sample was collected from each subplot each
quarter, until the concentration of TCICs in the soil in the subplot was less than 100 mg/kg. An additional lift
of soil from the stockpile area then was placed in the subplot. The process was repeated until all of the
stockpiled soil had been placed in the land treatment area.
4-6
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