Cleaning up old TR coal gas plant
TWO RIVERS – It's time to clean up the environmental pollutants left behind by a manufactured gas plant that ceased operations nearly seven decades ago.
"It is the right thing to do for the community and the environment ... and we would like to get regulatory closure from the EPA and DNR," said Naren M. Prasad, a senior environmental engineer with Integrys.
That is the parent company of Wisconsin Public Service Corp., which operated a manufactured gas plant site on 21st Street, near the West Twin River, from 1925 to 1946.
Prasad said coal was superheated and a gas was produced for basic uses including indoor heating and lighting. But the manufacturing and purification processes produced by-products including coal tar, which can contain known or suspected cancer-causing agents and other potentially hazardous chemicals.
Integrys-WPSC has signed an "order on consent for removal action" with the U.S. Environmental Protection Agency to remove to landfill or bury on-site in a concrete slurry some 70,000 cubic yards of the coal tar on the 4-acre site.
An EPA document indicates there are "high levels of hazardous substances in surface and sub-surface soil at concentrations" exceeded what the federal agency and state Department of Natural Resources allows.
The removal to landfill of 20,000 cubic yards or "in-situ solidification stabilization" (ISS) of the remaining 50,000 cubic yards of coal tar is to be completed mid-2015.
Prasad said ISS both physically and chemically solidifies and stabilizes the contaminated soil into a material resembling columns of low-strength concrete at ground level and below. ISS mixes a cement-like grout with impacted soil using large diameter augers.
City Manager Greg Buckley said the contaminants are rendered inert, and while they remain on-site are unable to further impact groundwater or adjacent wetlands. He said after cleanup is completed the site will be covered with topsoil and maintained as a green field.
Considering that active planning for cleanup has been ongoing for more than 10 years, he said civic officials are pleased to see WPSC and the EPA moving forward.
Buckley said the site is part of a larger 24-acre complex of properties on the West Twin River, including the former Seneca Oil site and former U.S. oil tank farm, that is identified as a potential "smart growth" redevelopment area in the city's 2010 Comprehensive Plan.
Time critical
The EPA said the removal is "time critical" considering the "site's plans for future construction, the potential exposure to children trespassers and the industry-commercial use of nearby property."
Excavation crews began removal last month and Prasad there will be a work break during the winter when digging into the ground can be problematic.
"Air samples will be collected and analyzed throughout the project to ensure that nothing harmful is being released," Prasad said.
WPSC's former manufactured gas building on 21st Street and other structures and foundations were demolished over the years in an area the EPA said was historically industrial.
An EPA update document indicated sandbag dikes and an underwater "curtain" will be installed along the river to prevent any contaminated soil from entering the water.
"Neighbors will probably notice engine noise from the equipment used in the stabilization process, extra truck traffic during the dig'n'haul activities, and air monitoring stations making sure excess dust isn't released into the air," the EPA document states.
For additional information on site cleanup, visit www.epa.gov/region5/cleanup/tworivers.
Charlie Mathews: (920) 686-2969 or cmathews@htrnews.com