Indiana Harbor Main Page
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Treatment
Technology
The
Corps of Engineers has considered a wide range of technologies for treating the
sediment from Indiana Harbor and Canal.
To be effective at Indiana Harbor, a treatment technology would address
all of the contaminant concerns for the sediment: very high metal
concentrations, very high oil and grease content, very high volatile and
semi-volatile organic compound concentrations, the presence of polychlorinated
biphenyls, and high nutrient (nitrogen and phosphorus) concentrations. Unless
all of the contaminants are removed, the sediment will still need to be
confined in a disposal facility. The
types of technology which the Corps has considered include the following:
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Incineration based technologies: - Plasma arc furnace - Thermal desorption - Combustion using molten metal - Combustion using molten salt - Gas phase chemical reduction - Rotary kiln incineration |
Limitations of incineration technologies: These technologies address the oil and grease and organic compounds, but do not treat metals. Incineration creates air pollution and leaves solid waste (ash or slag) that needs to be landfilled. |
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Extraction technologies: - Solvent extraction - Soil washing - the BEST (basic extractive sludge treatment) process - Supercritical fluid extraction |
Limitations of extraction technologies: These technologies separate contaminants from the soil particles, but do not destroy contaminants. Most technologies work for one type of contaminant (for example, a solvent that works for removing metals won’t work for removing organic compounds), so that multiple treatments would be needed to remove the contaminants from the sediments. The large volume of extracted contaminants still needs treatment or disposal. Some of these processes create air pollution. |
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Chemical oxidation or reduction technologies: - Supercritical water oxidation - Electrochemical oxidation - Solvated electron process - Catalytic hydrogenation - Base catalyzed dechlorination |
Limitations to chemical oxidation and reduction technologies: The purpose of these technologies is to remove chlorine atoms from organic compounds, making the compounds less toxic. Some organic compounds may be destroyed, but most of these technologies do not completely destroy organic compounds. The waste stream may be strongly reacting solutions which need additional treatment. |
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Biological treatment technologies: - Slurry phase biological treatment - Phytoremediation (using plants) |
Limitations to biological technologies: These technologies may not work on metals. Nutrients can be degraded, but any other biological remediation may take a long time to complete. The sediment at Indiana Harbor and Canal may be too contaminated to support plant growth. Corps of Engineers Detroit District is completing on-going studies at Milwaukee and Green Bay. |
The Corps of Engineers and
the U.S. EPA will continue to evaluate new technologies which may be
appropriate for Indiana Harbor. Find out more about contaminated sediment
issues at the following web sites:
USACE Waterways
Experiment Station, Center for Contaminated Sediments: http://www.wes.army.mil/el/dots/ccs/
The Great Lakes National
Program Office: http://www.epa.gov/glnpo/
The Great Lakes Dredging
Team: http://www.glc.org/projects/dredging/