A primary mission of BNL's Environmental Restoration Division is the remediation of soil and groundwater contamination and the prevention of additional contamination migrating off the Brookhaven site.
To that end, three groundwater treatment systems are currently operating at BNL, with a fourth now under construction. The map (right) shows the four systems and their locations. To summarize each system and its purpose:
Operable Unit III Remediation System: Construction of the Operable Unit III pump-and-treat system was completed in June, and the system is now working at full capacity. The system uses six wells to extract contaminated groundwater from the aquifer. The water is pumped to an air stripping tower, where air from a powerful blower separates volatile organic compounds (VOCs) from the water. The clean water is recharged (returned to the ground) and the VOCs are released into the air at concentrations below state and federal emissions standards.
The system was constructed to treat a plume of VOCs moving south from unidentified sources (still under investigation) in the developed central portion of the Lab site. It is currently processing approximately 600 gallons of water per minute. After the VOCs are removed, the clean water is discharged into a new recharge basin located approximately one mile north of the site's southern boundary.
Operable Unit I/Removal Action V Pump-and-Treat: This system (operational since December 1996) was constructed to remediate a plume of VOCs originating from the Lab's Current Landfill (now closed and capped) and the Hazardous Waste Management Facility. It uses two extraction wells to process more than 700 gallons of water per minute, and, like the Operable Unit III system, removes close to 100 percent of the chemical contamination.
Tritium Remediation System: Three groundwater extraction wells have been installed 3,500 feet south of the High Flux Beam Reactor's spent fuel pool to address the on-site tritium plume. Tritiated groundwater is pumped from the aquifer at a rate of about 120 gallons per minute and piped north to a treatment facility and recharge basin. The water is treated with carbon to remove chemical contamination that is also present in groundwater in the area due to other past BNL activities. The system, constructed as an interim action, will prevent tritiated water above the U.S. Environmental Protection Agency's drinking water standard of 20,000 picocuries/liter from leaving the Lab site while remediation options for the higher concentrations of tritium close to the reactor are evaluated.
Operable Unit IV Air Sparging/Soil Vapor Extraction System: This
remediation system, now under construction, combines two technologies to
remove contaminants from soil and groundwater. Air sparging and soil vapor
extraction work together, forcing pressurized air into the groundwater to
bubble these volatile compounds out of the water and soil and carry them
upward. Powerful vacuum pumps then recover the resulting vapors and pipe
them to a treatment facility. The system is being constructed to treat soils
and groundwater containing volatile and semi-volatile organic compounds
from a 1977 fuel oil spill.