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Scope of Work:
- Site preparation required clearing and grubbing, removal of surficial debris, demolition of a former office and warehouse, and installation of all erosion and sedimentation controls over a 10-acre site.
- The excavation plan called for a complicated 50’x50’ grid system of excavations in 2’ increments to terminal depths of 6-9’ below grade. Excavation grids typically contained a combination of both TSCA and non-TSCA layers were then segregated for treatment or disposal. Excavations also frequently encountered drums with unknown wastes that required special handling.
- Non-TSCA soils were pre-processed prior to low temperature thermal desorption (LTTD). Pre-processing including screening out debris to a 2” minus specification and moisture conditioning with either quicklime or lime kiln dust (as needed).
- Non-TSCA soils were then thermally treated in ESMI’s mobile thermal treatment plant where all organic contaminants (PCBs, VOCs, SVOCs) were destroyed. Treatment rates typically exceeded 30 tons per hour despite poor soil conditions. Over 45,000 CY of soil was successfully treated by ESMI without a single pile failure.
- Approximately 33,000 tons of TSCA soil and debris were shipped to an off-site TSCA landfill for disposal. An additional 21,000 tons of non-TSCA debris (from screening) was also shipped to a non-hazardous landfill.
- Groundwater was consistently encountered at approximately 5’ and required full time dewatering management and on-site water treatment. DAC provided a 200-gpm water treatment system which utilized extensive particulate filtration, organoclay, and activated carbon to treat to surface water standards. Over 9.6 million gallons were treated and discharged to nearby local stream.
- Due to residential proximity, the community air monitoring program included four fixed air stations with both real time monitoring for dust and VOCs and documentation sampling for PCBs, PM10 dust, and VOCs. Odor suppression and dust suppression were highly prioritized in order to mitigate community nuisance concerns.
- All treated soils were reutilized as backfill material and the site was restored with imported topsoil and vegetation.
- All site facilities and utilities needed for construction and operation of the LTTD plants were installed by DAC. Utility services included a temporary gas, electrical, water, and communications. The LTTD plant was situated on a temporary concrete slab (over 1,200 CY of concrete) which was removed at the end of the project.
- Extensive media sampling was performed for untreated soils, treated soils, post excavation confirmatory sampling, air sampling, water treatment sampling, and equipment decontamination.
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