This project was completed for the purpose of removing highly PCB-contaminated sediment from the walls and floors of a raceway system located in a former industrial property in Lawrence, MA. IAI utilized a specially equipped electrically powered hydraulic dredge to remove the contaminated sediment from the sub-surface and external raceways, dewatered the dredged material in geotextile tubes and treated the geotextile tube weep water in a temporary treatment system on site prior to discharge under an NPDES permit issued by Massachusetts Department of Environmental Protection.
Contaminants of Concern
- PCBs, up to 18,000 ppm
- Extractable petroleum hydrocarbons, up to 160 ppm
- Naphthalene, up to 13 ppm
- Metals
- Volatile Organic Compounds (VOCs)
- Semi-Volatile Organic Compounds (SVOCs)
Health & Safety
Personnel health and safety was addressed very carefully at the site, due to several complicating factors. The biggest challenge was that the sub-surface raceway system was determined to be a permit-required confined space, so all of the requirements of OSHA’s confined space regulations had to be incorporated into operating procedures, including: confined space permits, continuous air monitoring, respiratory protection, continuous communication with confined space attendants and rescue personnel on site at all times. IAI provided a Certified Industrial Hygienist to direct site safety and health activities, as well as confined space rescue personnel, and all IAI site personnel were confined space entry and OSHA 40-hour HAZWOPER trained.
Remediation Services
IAI was contracted by the site owner to:
- Dredge about 2,000 cubic yards of highly PCB-contaminated sediment from the permit-required confined space of the sub-surface raceways and external raceways
- Design and construct a header system for delivering pumped sediment to geotextile tubes for dewatering
- Install and operate chemical feed system to flocculate pumped sediment
- Utilize geotextile tubes to dewater the pumped sediment
- Install, operate and maintain water treatment system to treat geotextile tube weep water
- Support hydro-blasting operations to remove contaminated residue from raceway walls
Remediation Equipment Utilized
- 4 inch diameter electrical hydraulic dredge and 4 inch HDPE header system
- Chemical feed system for dredge slurry flocculation
- 360 lineal feet of 75 foot circumference geotextile tubes
- 200 gpm on-site wastewater treatment system including pressurized sand filter, greensand filter, Granular Activated Carbon (GAC) adsorption units and microfiltration unit
