Top, at right: The original mill site is shown in this aerial view taken in December 1999 before demolition operations began. All photos: Ken Dow, www.cattailpress.com. Far right: The newly constructed bridge and roadway for state Routes 7 and 11 and the relocated Sebasticook River channel can be seen in the foreground of this photo. In the background, only a few foundations remain of the former mill.
Bottom, at right: Steam rises as a bulldozer spreads hot, clean soil removed from the decontamination beds and dumped on the former mill site. Far right: By October 2003 the soil decontamination phase was complete and crews had begun removal of the soil desorption bins. This bin had been one of eight stationary treatment bins constructed to treat 500 tons of soil per batch.
Another critical element of the project was removing 100,000 tons of chlorinated benzene-contaminated soil and sediment and treating it with a low-temperature thermal treatment (LTTT) system. This system was more cost-effective than other treatment options and well-suited to the phased approach required for relocation of the road and bridge.
The LTTT system was designed as an onsite system to thermally desorb contaminants from soils. It included stationary treatment piles, hot-air injection, process emissions extraction and treatment, and control/monitoring equipment.
The hot-air injection system consisted of indirect-fired propane process heaters, a boiler for steam addition (this minimized the time required to reach target temperature and maintain adequate soil moisture content), and an underground system of injection piping connected to perforated pipes at the bottom of each pile. The perforated pipes were then covered with a layer of stone to prevent soil from clogging the pipes and to facilitate soil loading and unloading. This treatment system was highly effective, reducing the concentration of contaminants by more than 90% and producing a soil safe enough for reuse on site.
To access the contamination, the EPA needed to relocate state Routes 7 and 11 and remove the associated bridge. A temporary road bypass was designed as a permanent feature that resulted in significant benefits to the EPA, the town, and the state. The town of Corinna and the DOT had long been considering a realignment of state Routes 7 and 11. As a result of partnering between federal, state, and local agencies a permanent road and bridge alignment satisfying all stakeholders was agreed upon. This cooperation also resulted in significant cost savings.
In addition to causing a significant social and environmental degradation of the area, the contaminated Eastland Woolen Mill facility had also presented a major impediment to economic recovery. With the source of contamination removed from the former mill property, the area is now ready for redevelopment. The cleanup even helped to improve water quality in the downtown section of the East Branch of the Sebasticook River, which previously had been designated a non-attainment area.Looking Forward
During the initial planning stage, it was estimated that the project would take 18 months, cost $10 million, and require removing 22,000 cubic yards of soil. Once the project got underway, the contamination proved much more extensive—more than 102,000 cubic yards of soil were removed. The budget was revised to $48 million with a completion date of December 2006.
In the end, though, the excavation and thermal treatment of soil were completed ahead of the original projection, allowing site redevelopment to occur according to the original schedule. The project was streamlined by relocating the roadway, bridge, river, historic structure, and utilities just once to a new location and not moving them back.
According to Galen McKenney, who serves as chairman of the board of selectmen, the town was able to implement a redevelopment plan a year ahead of schedule with a 21-unit senior housing development downtown now serving; as an anchor for the town's redevelopment program.
“We received an $80,000 EPA grant to do a reuse plan for the reclaimed area, which is now done. The end result will be a mixed-used development of retail shops, housing, and green space,” he said. “We're hopeful that this will bring in more jobs and increased tax revenues. This project saved our town and is the greatest thing to happen here in 100 years.”
— Baker is a project manager with MACTEC Engineering and Consulting Inc.