A former wood-treating facility had previously been located on the project site; each of two ponds contained a layer of thick, black oily sludge. The sludge was contaminated with creosote, polyaromatic hydrocarbons and metals.
To remediate the ponds, the sludge was removed with utilization of a suspended pump and dewatered in geotextile tubes. IAI and its subcontractors constructed a dewatering pad by leveling a large area, building berms around it and lining it with high-density polyethylene (HDPE) liner to prevent groundwater contamination.
A centrifugal pump was used to pull the loose sludge from the ponds and deliver it to Geotube® containers which had been placed around the circumference of the dewatering pad for dewatering. The remaining portion of the sludge from the ponds was removed mechanically and placed in the center of the dewatering pad to dry.
Filtrate from the Geotube® containers and separated water from the mechanically-excavated sludge was collected and treated in a temporary on-site treatment plant before being discharged back into the ponds.
Due to the contamination in the pond sediment, all operations were covered under OSHA standard 1910.120 (the Hazardous Waste Operations and Response or HAZWOPER standard).
- Mechanical excavation to remove some of the sludge
- Oily, creosote-contaminated sludge
- Sludge pumping operation
- Polymer system used to flocculate pumped sludge prior to dewatering
- Geotextile tubes used to dewater pumped sludge