Thermally Enhanced Soil Vapor Extraction/Bioremediation at Former Chemical Plant
Lead Design Firm: CHA Consulting Inc.
General Contractor: Cascade Thermal
Specialized Treatability Consultant: XDD Environmental
After a Schenectady, N.Y., factory that produced enamels, varnishes and other resins for more than 80 years—and had a history of chemical spills—finally closed in 1997, New York’s environmental authorities designated the property a state Superfund site for both groundwater and soil contamination.
Testing and analysis of the site’s conditions took place in the years afterward, along with early remediation work, with the state finally determining it would attempt to remove groundwater pollution with a thermally enhanced soil vapor extraction process, which includes an air injection technology that uses heat to cause the biodegradation of contaminants. The toxic materials were as deep as 15 ft below the ground surface across a 1.6-acre site.
Adding to the complexity was the site’s location in a residential neighborhood, with a railroad and creek downhill from the main work area. The team strived to minimize the impact of truck traffic through the neighborhood and to limit noise, dust and odors—with the project logging no complaints from residents or nearby businesses across two years.
The project entailed challenges to conventional methods such as excavation and disposal—including the need for shoring for nearby infrastructure and stabilizing the slopes on the site.
Instead of using standard high-temperature thermal remedies, the team opted for a less common low temperature thermally enhanced soil vapor extraction technique, which limited impact on the community—and resulted in a lower project cost than other methods.
With work starting in 2016 and wrapping up late in 2018, the team proved the low temperature method combined with a targeted oxygen delivery system was able to heat the subsurface and stimulate biological degradation. The system entailed installing soil vapor extraction and dual phase extraction wells to test and dewater the treatment zone, custom blowers and a groundwater treatment system as well as piping, hoses, gauges and valves.