The patented ELI Eco Logic International Inc. (Eco Logic), process (see photograph below) uses a gas-phase reduction reaction of hydrogen with organic and chlorinated organic compounds at elevated temperatures to produce a hydrocarbon-rich gas product. During the SITE demonstration, soils were pretreated within Eco Logic's thermal desorption unit (TDU), which was operated in conjunction with the reduction reactor. For further information on Eco Logic's TDU, see the profile in the Demonstration Program section (completed projects).
Gas-Phase Chemical Reduction Process
The gas-phase reduction reaction takes place within a specially designed reactor at ambient pressure. Separate nozzles inject gaseous atomized waste, steam, and hydrogen into the reactor. As the mixture swirls down between the outer reactor wall and a central ceramic tube, it passes a series of electric glo-bar heaters, raising the temperature to 850 °C. The reduction reaction takes place as the gases enter the ceramic tube through inlets at the bottom of the tube and travel up toward the scrubber. The scrubber removes hydrogen chloride, heat, water, and particulate matter. If necessary, scrubber liquid may be recycled through the system for additional treatment.
For waste with a low organic content, the majority of the hydrogen-rich gas recirculates to the reactor; the remainder can be used as a supplementary fuel for a propane-fired boiler that produces steam. Processing waste with a high organic content produces excess gas product, which can be compressed and stored for later analysis and reuse as supplementary fuel.
The unit is mounted on two standard, drop-deck, highway trailers. A computerized process control system allows the operator to monitor process variables such as temperature, pressure, hydrogen content, and oxygen levels. In addition, an on-line mass spectrometer is used to continually monitor selected organic compounds.
The Eco Logic process is designed to treat aqueous and oily waste streams and soil or sludge contaminated with hazardous organic waste such as polychlorinated biphenyls (PCB), polynuclear aromatic hydrocarbons, chlorinated dioxins and dibenzofurans, chlorinated solvents, chlorobenzenes, and chlorophenols. Wastes with high water content are easily handled by the process since water is a good source of hydrogen.
In October and November 1992, the Eco Logic process was demonstrated at the Middleground Landfill in Bay City, Michigan, under a Toxic Substances Control Act research and development permit. The demonstration was conducted in cooperation with Environment Canada and the Ontario Ministry of the Environment. The test was performed using PCB-contaminated wastewater, waste oil, and soil from the site. The Demonstration Bulletin (EPA/540/MR-93/522) and the Applications Analysis Report (EPA/540/AR-93/522) are available from EPA.
Since the SITE demonstration, Eco Logic has developed a commercial-scale system (the SE25) which is designed to treat 100 to 300 tons per day of contaminated soil or sediment and 20 tons per day of PCB liquid. The SE25 combines the reduction reactor, which treats PCB oils and aqueous wastes, with a redesigned TDU, which treats contaminated soils and sediments and an SBV for treating bulk solids such as electrical equipment, drums, and personal protective equipment.
Two commercial-scale SE25 treatment units are currently in operation; one in Perth, Western Australia, and the other at a General Motors of Canada Ltd (GMCL) facility in Ontario. Both are currently treating a variety of waste matrices, including DDT residues and PCBs in soil, oils, electrical equipment, concrete, and other solids. Following the GMCL project, the unit will be relocated to Toronto, Ontario where General Electric (GE) and Eco Logic have a contract to destroy PCB-impacted materials stored aboveground at GE's Lansdowne and Davenport facility. Eco Logic has also been awarded a contract through the Department of Energy's Morgantown Energy Technology Center for treatment of hazardous wastes, radioactive mixed low-level wastes, and energetics-explosives.
During the demonstration, two separate waste feed conditions were used:
(1) wastewater containing an average PCB concentration of 4,600 parts
per million, and (2) waste oil containing an average PCB concentration of
24.5 percent. Both feeds were tested in triplicate. The demonstration of
the Eco Logic process yielded the following results:
EPA PROJECT MANAGER:
Gordon Evans
U.S. EPA
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7684
Fax: 513-569-7787
TECHNOLOGY DEVELOPER CONTACT:
Jim Nash
ELI Eco Logic International Inc.
143 Dennis Street
Rockwood, Ontario, Canada
N0B 2K0
519-856-9591
Fax: 519-856-9235