EP 1110-1-19
30 Jun 01
Exhibit 4-4, cont.
Example Construction Activities (Section 3)
In general, the soil for each lift was placed 4 to 12 inches thick in the land treatment area and inoculated with
PAH-degrading microorganisms. The inoculum, sprayed on the soil, was developed by growing seed
cultures in mobile, on-site reactor tanks equipped with aeration and mixing equipment. The land treatment
area was cultivated once every two weeks. An irrigation system was used to maintain a 10-percent soil
moisture content. The concentration of microorganisms in the soils at the land treatment area was found to
be adequate to support biological activity, and no inoculum was applied for the second or third lift.
Additionally, the total number of lifts applied to each subplot varied because several of the half-acre areas
exceeded the TCIC concentrations of 100 mg/kg. Subsequently, no additional soil was placed in those
subplots until the analytical results indicated less than 100 mg/kg.
Appendix A reports matrix characteristics and operating parameters of the land treatment system.
Approximately 50 cubic yards of construction debris were removed from the soil and buried on the site.
After validation of the final sampling results and determination that the remediation objectives had been met,
the site was backfilled with clean soil and seeded on September 1, 1998.
4-5. Chronology of Events. This section should provide a tabular summary that lists the
major events for the OU, and associated dates of those events, starting with the ROD signature.
The table should include significant milestones and dates, including: RD submittal and approval;
ROD amendments; mobilization and construction of the remedy; treatment system/application
start-up; monitoring and sampling events; system modifications; operational down time;
variances or non-compliance situations; date of final shut-down or cessation of operations; final
sampling and confirmation-of-performance results; required inspections; demobilization; and RA
completion or startup of post-RA O&M activities. If an O&F period applies, indicate the start
and end dates. For interim RA reports, indicate when cleanup goals are estimated to be
achieved. An example chronology is provided in Exhibit 4-5.
Exhibit 4-5
Example Chronology of Events (Section 4)
Date
Event
March 8, 1996
ROD for OU2 signed.
August 3, 1996
Remedial Design (RD) submitted.
September 15, 1996
RD approved; ROD amendment signed.
September 29, 1996
RA contract awarded.
Construction of the land treatment area began, including excavation of contaminated
October 3, 1996
soil..
December 1, 1996
Solidified waste from OU1 transported and disposed of off-site.
December 12, 1996
PRPs, EPA, and the State conduct pre-final inspection of the land treatment area.
January 12, 1997
PRPs, EPA, and the State conduct final inspection of the land treatment area.
Operation of land treatment area begun; first lift of soil applied to treatment subplots;
January 19, 1997
sampling of soil in treatment plots begun.
4-7
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