< Back to project list
|
|||||||||
|
Scope of Work:
¨ Site preparation included clearing and grubbing of approximately 3 acres of mixed hardwood and softwood forest and installation of erosion and sedimentation controls. Environmental controls included both personal and perimeter air monitoring for VOCs and particulates.
¨ Excavation of approximately 50,000 tons of PCE and TCE contaminated soils. Excavation depths were typically 30’ below grade, or to bedrock with some locations requiring trenching methods and / or sheeting in areas adjacent to the state highway. Due to the bedrock exposure, the project included a complex sheeting design which required bedrock drilling and pinning.
¨ Groundwater was collected from the excavations and stored in five Modutanks providing total storage of 200,000 gallons. The water was then treated through a 50 gpm system consisting of bag filters and carbon filters. Total volume treated exceeded 1 million gallons. The majority of the treated water was used in the evaporative cooling chamber of the thermal treatment plant. The remainder was discharged to a surface drainage ditch in accordance with state drinking water standards.
¨ Excavated soils were stockpiled for pre-processing prior to thermal treatment. Pre-processing included screening and crushing of all material to a 2” minus standard. Oversized material that could not be crushed was decontaminated manually and used as hard fill. Due to vapor emissions during soil handling, much of the soil processing was performed inside a 75’ diameter temporary fabric structure. All work inside the structure was performed under Level C personal protection with full time ambient air monitoring.
¨ After screening and crushing, the soil was treated in the mobile thermal treatment plant. The thermal treatment plant utilized an ASTEC rotary kiln to heat the soil to 800 degrees with a 15 minute residence time. Treated soil was re-moisturized and stockpiled for subsequent confirmatory analysis. Total daily production averaged 800 tons per day based on 24 hour, 7 day per week operation.
¨ The facility operated under a NYS DEC permit equivalency and successfully achieved the required 99.99% destruction removal efficiency (DRE). This was confirmed through biweekly stack testing for TCE, PCE, Dioxin, HCl, CO, metals, and particulates.
¨ Treated soil was sampled after every hour of production, in approximate 35 ton batches. All samples were analyzed on-site using a mobile laboratory and confirmed off-site by an ELAP certified laboratory in accordance with Level IV Data Validation protocol.
¨ Upon receipt of acceptable confirmatory analysis, the treated soil was placed back into the excavations as clean fill. Compaction occurred in 1’ lifts to 95% maximum dry density. All compaction was confirmed via nuclear density testing. |
|||||||||