NORWICH – On Thursday, the New York State Department of Environmental Conservation will hear public comments on a proposed $11.2 million remedial plan for a property located on Birdsall Street in the City of Norwich.
The former NYSEG Manufactured Gas Plant (MGP) site, located at 24 Birdsall St., produced coal gas and what’s known as carburetted water gas until 1953. The production of the gases included a cooling process, which utilized ground water as a bottom seal for cooling and pressure purposes, which significantly increased the potential for byproducts to be introduced into the ground water and subsurface area.
While remedial action was taken at the site several times, the DEC and the Department of Health are proposing further action be taken to address contamination.
According to representative Diane Carlton, the DEC has recommended a process known as “in-situ” solidification of the on-site sub-surface soils, as well as two off-site properties. It’s also calling for the collection and removal of mobile coal tar from beneath off-site areas, further in-situ chemical oxidation treatment of off-site contaminated soils, enhanced bioremediation of groundwater and an environmental easement.
In-situ solidification prevents groundwater from traveling through the contaminated soil. The process would require the top six feet – approximately 1,800 tons – of soil to be removed from the site and disposed of before a cement or clay like material was brought in. The clay would be mixed with the existing soil, using a large auger.
“The ISS process prevents ground water from passing through the soil. The contaminants are maintained with in the soil, reducing the potential for contamination migrating off site,” Carlton explained.
The total cost of the DEC’s proposed remedy is approximately $11.2 million. Construction costs account for approximately $10.8 million. The cost to monitor and maintain the sites is estimated at $120,200 a year for 20 years.
In addition to the ISS process, the proposed plan calls for the collection of mobile coal tar from an off-site area located to the south of Front Street. The coal tar and contaminated water would be collected from a total of 12 collections wells for disposal. In-situ chemical oxidation, a process that involves the introduction of a chemical oxidant into the subsurface for the purpose of transforming ground water or soil contaminants into less harmful chemical species, would then be performed at the site to treat the remaining material.
Periodic monitoring and maintenance will continue for approximately 20 years.
Carlton explained that the DEC’s proposed actions were determined by considering which options would have the best remedial impact while still being cost effective.
Additional information on the history of the MGP site and the proposed remedial action is available at the Guernsey Memorial Library in Norwich. A public meeting will be held at 7 p.m. Thursday in the second floor conference room at the Norwich Fire Department. Citizens will have an opportunity to comment on the proposed plan.
Written comments can also be submitted to Mr. Anthony Karwiel, Project Manager, NYSDEC Central Office, 625 Broadway, 11th Floor, Albany, NY 12233. Comments must be postmarked no later than March 24.