NORWICH – Cleanup and decontamination work which began in late October will continue throughout the winter and early spring at a former New York State Electric and Gas (NYSEG) plant, behind Front and Birdsall Streets and adjacent to the Tops parking lot.
Phase one of the cleanup will include the collection and disposal of coal tar oil and contaminated groundwater, the in-situ solidification of impacted soils and the installation of a clean soil cover, according to the New York State Department of Environmental Conservation (DEC), which ordered the cleanup in March of 2008.
The in-situ solidification process involves the utilization of a nozzle-equipped auger, which injects a cement-bentonite mixture into the ground, according to NYSEG Manager of Regional Outreach and Development James Salmon. When the mixture cures, it prevents the byproducts of outdated manufacturing gas plants from migrating or dissolving into the groundwater. This “cured” mixture can then be easily excavated using standard construction equipment should the need arise in the future, he added.
A private contractor, hired by NYSEG, will perform the cleanup and decontamination, with oversight provided by the NYSDEC and the New York State Department of Health.
Originally utilized for the manufacturing of natural gas from 1863 to 1953, the site now contains an unknown amount of discharged coal tar oil, and the goal of phase one is to remove and dispose of the contaminant and the soils containing it.
Primary activities during this phase, according to the DEC, include mobilization and site preparation; community air monitoring and continued collection of mobile coal tar oil and heavily contaminated groundwater.
Phases two and three of the decontamination effort will focus on a second, smaller site, near the railroad tracks on the south side of Front Street.
Phase two – which began in the spring of 2009 and continued through November of the same year – is the physical removal of coal tar via a pumping process, said Salmon. The pumping resumed in the April of 2010 and recently halted once again due to the onset of winter, he added.
“NYSEG will resume pumping in April of 2011 and will continue pumping until no more coal tar can be removed,” stated Salmon, who added a total of 51,000 gallons of coal tar-water mixture containing approximately 25,500 gallons of coal tar had been removed from the phase two area to date.
Phase three will also focus on the smaller site on the south side of Front Street and includes in-situ chemical oxidation followed by enhanced biological treatment. Oxidizing chemicals will be injected into the ground which will attack and destroy any remaining coal tar and break it down into carbon dioxide and water, reported Salmon.
Following that process, Salmon said oxygen will be pumped into the ground, stimulating naturally existing bacteria and destroying any remaining pockets of manufacturing gas plant byproducts.
“They’re very much on schedule at this point in time and there have been no major problems to date,” stated Mayor Joe Maiurano of phase one. “The area is being monitored for air quality on a daily basis to make sure the air quality is safe.”
According to the mayor, holding phase one of the project during the winter months will help keep down the dust which, otherwise, may have hampered the cleanup effort.
“In conjunction with our commitment to environmental stewardship, NYSEG has long been a leader in investigating and, as needed, cleaning up former manufactured gas plant sites,” stated Salmon. “We remain committed to that effort.”