EPA go-ahead starts cleanup at Montville Power's plant site

Most of the pollution at the plant on the Thames River dates to its previous owner, Northeast Utilities.
Most of the pollution at the plant on the Thames River dates to its previous owner, Northeast Utilities.

Montville - Montville Power LLC is taking measures to reduce the environmental and health hazards associated with polychlorinated biphenyls (PCBs) and other contaminants in the soil at its Lathrop Road plant.

The NRG Energy Inc.-owned company recently received approval from the Department of Energy and Environmental Protection to install engineered control devices at three locations on its property.

An engineered control involves placing a physical barrier over the contaminated soil, thereby preventing people who work or play in the area from coming into contact with the pollutants, said Mark Lewis of the DEEP Bureau of Water Management and Land Reuse.

In two of the three contaminated locations, this barrier will be a layer of asphalt. One of those sites contains arsenic and polynuclear aromatic hydrocarbons from the disposal of coal ash, said Lewis. The other location, where petroleum used to be stored in above-ground tanks, is contaminated with petroleum hydrocarbons.

A third location contains PCBs from soil that was dredged from the Thames River and deposited on the plant's property. The concentration of PCBs is high enough to meet the DEEP's "pollutant mobility criteria," explained Lewis, so this location requires a more complex device to prevent the contaminants from entering the water table. The polluted soil will be capped with a layer of sand and a plastic membrane to stop rain and snow melt from percolating downward before being topped with soil and planted with grass.

NRG hired a contractor, Shaw Environmental Inc., to manage the response to the pollutants. Groundwater monitoring by Shaw Environmental has shown that PCB contamination is not a current concern, said Lewis.

Most of the pollution on the site was generated by Northeast Utilities, which sold the plant to NRG Energy in the late 1990s. At the time of the sale, NRG pledged to do any needed hazardous material cleanup.



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