SECTION NINE
Observations and Lessons Learned
COST-RELATED
Costs on similar future projects could be reduced by taking preliminary steps to minimize the
chances for shutdowns caused by legal actions. Millions of dollars in costs were incurred while
the incinerator was shutdown pending the outcome of a lawsuit brought by an opposition group.
A significant cost savings was realized due to a change incorporated into the contract
specifications allowing for the cleaning and backfilling of excavated rock. The reuse of rock
eliminated costs associated with importing stone from an outside source.
The initial remedial design included laying cover material capable of supporting vegetation over
treated soil depleted of organic material. Two studies demonstrated that the addition of compost
and fertilizer to the treated soil would be sufficient to allow sustained growth of a vegetative
cover. The amended design resulted in elimination of costs associated with importing fill
materials and topsoil.
PERFORMANCE-RELATED
Project managers of future similar projects should perform a thorough review of the proposed
equipment layout plans. Equipment locations are particularly important to consider with material
handling systems. Bins and buildings to store and/or stabilize ash should be located in close
proximity to ash sources to minimize the amount of high wear/severe duty equipment (e.g.,
screw augers and drag conveyors) necessary.
The feed preparation area should be as large as physically possible to allow sufficient room for
any additional equipment, which may become necessary for trash separation, drum handling
operations, pre-drying and similar operations.
Dust suppression is an important aspect of managing soil and ash on-site. When possible, soil
and ash management operations should be conducted within an enclosed structure such as a
building under slight negative pressure or using enclosed equipment.
During the preliminary site investigation and incinerator conceptual design, the moisture content
of site soil should be characterized. Worst case moisture content should be included in the RFP
so the contractor design engineers can size the kiln and burners accordingly. Soil moisture will
greatly affect the allowable throughput rate and the ability of the system to remove contaminants
from the soil. A heat transfer specialist should do a thorough review of the assumptions and
calculations used to size the incineration equipment.
The temperature of the treated soil exiting the kiln is a primary indicator of whether the soil will
meet the treatment requirements. The contractor should measure the kiln exit soil temperatures to
obtain a real-time indication of the kiln efficiency, rather than waiting 72 hours for the analytical
results of the treated soil samples.
Due to the severe environments under which they operate, the ash conveyance system may be
particularly susceptible to mechanical failure. A thorough review of the contractor's proposed
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Slippery Chemical OU 3 Final RA Report
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