investigations of the river bottom have taken place during the 1980s and 1990s. Two areas of the river have undergone
demonstration dredging in the past five years.
While planning the appropriate remedial response to be undertaken, the Wisconsin Department of Natural Resources (DNR) requested input from the public. Minergy proposed a feasibility study to determine the potential to use a glass furnace capable of melting the contaminated river sediment at high temperature, thereby destroying the PCBs and binding any metals in the glass aggregate produced. Such furnaces have been used for decades to make glass. Feedstock consisting primarily of silica sand (which is the main constituent of river sediment) melts in the furnace. The molten product is cooled to form glass aggregate, which is a marketable construction material.
This report is written to summarize the activities undertaken during Phase 3 of the multi-phase glass furnace feasibility study. The first two phases of the feasibility study determined that the minerals contained in dredged sediments could form a stable glass, and that the variability of mineral concentrations along the lower Fox River appeared to be within acceptable ranges. Results from these phases are available in reports sent to the Department under separate cover.
During one of the demonstration dredging projects, the DNR containerized approximately 60 tons of de-watered,
contaminated river sediment. The DNR contracted with Minergy for the design, construction, and operation of a pilot melter, to melt the sediment into a glass aggregate.
The U.S. EPA Superfund Innovative Technology Evaluation (SITE) program was used to perform an independent evaluation of the fate of PCB and other contaminants for Phase III. The dryer segment of the analysis was performed at the Hazen Research, Inc. facility in Golden, Colorado in January 2001. At that location, Hazen has a demonstration-scale dryer of the appropriate technology for use on sediments.
The melter evaluation was performed at Minergy’s GlassPack Test Center in Winneconne, Wisconsin. A demonstrationscale melter was constructed, with operation of the melter from May to August, 2001. The pilot program was designed to confirm that the technology can destroy PCB contamination, stabilize trace metals, and convert the mineral content of river sediment into an inert, marketable construction material.
Under SITE program, the fate of PCBs and other compounds within the river sediment were monitored during the processing and melting of the river sediment. The SITE program test results will be submitted under separate cover by the EPA contractors responsible for gathering that data.