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City of Kitchener T.(519) 741-2303 F.(519) 741-2624 
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| Contact Information | |
| Electrohome Limited | |
| Start Date: | 1/1/2000 |
| End Date: | 1/1/2003 |
| Location: | Kitchener, Ontario |
| Project Scale: | Completed. |
| Media Treated: | Soil. |
| Clean up of Site Involved: | Site Characterization & Assessment, Treatment, Removal. |
| Site Condition: | The geology of the site, extending from the ground surface to depth, includes a 6 m surficial aquifer (sand), a 3.5 m upper clay-confining layer, a 7.5 m intermediate aquifer (sand), and a second clay-confining layer. The groundwater flows northward in both the surficial and intermediate aquifers.The property in Kitchener that has become contaminated with trichloroethene (TCE), an industrial degreasing solvent.All possible phases of TCE contamination were investigated. The detected phases of TCE at the subject site included: 1. Residual TCE adsorbed on soil particles 2. Dissolved phase TCE 3. Vapour phase TCEThe presence of pure phase TCE, or Dense Non-Aqueous Phase Liquids (DNAPLs), was extensively investigated, but was not found during the Phase II investigation. Of the four possible phases of TCE, dissolved phase and vapour phase TCE were the most critical because they represented the greatest risk to public health and the environment. Dissolved phase TCE was detected in both the surficial and intermediate aquifers and in the upper clay confining layer.The natural biological breakdown products of TCE, including cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC) were also detected in these same geologic units. The maximum dissolved phase concentrations of TCE, cDCE, and VC were approximately 340 mg/L, 380 mg/L, and 13 mg/L, respectively. The maximum concentrations of vapour phase TCE, cDCE, and VC were 1,014 mg/m3, 778, mg/m3, and 49 mg/m3, respectively. The contaminant plumes were fully delineated in both the surficial and intermediate aquifers. The plumes were found to extend off-site to the north approximately 150 m in both aquifers. |
| Proposed Site Usage: | Commercial use |
| Reasons for Success: |
§ Since XCG constantly keeps up-to-date with the latest new and emerging technologies, XCG was able to immediately identify an alternative remedial approach that would be more cost effective at the subject site. This preferred remedial technology is Multi-Phase Extraction (MPE). The costs saving compared to conventional pump and treat at this site was app. 4 million. § The risk assessment indicated that the risks to existing residential and industrial neighbours were within acceptable risk limits. § The site-specific clean-up criteria for soil, groundwater and soil vapour were approximately one order of magnitude less stringent that the MOEE generic guidelines, and were still fully protective of public health and the environment. § The RAP provided a detailed work plan for each of these components. The RAP also provided a contingency plan based on more conventional remedial technologies in the event that the pilot-scale demonstration would reveal that remediation targets were not being achieved. |
| Regulatory Approvals Required: | n/a |
| Exceedance of Set Standards: | n/a |
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Technologies Used: |
XCG preferred the remedial technology: Photocatalytic Oxidation and the Multi-Phase Extraction (MPE). They developed a remedial Action Plan (RAP) for a MPE system.XCG developed a Remedial Action Plan (RAP) that evaluated the possible remedial approaches including conventional approaches such as: § pump-and-treat and § soil vapour extraction; and, emerging technologies such as § Multi-Phase Extraction (bioslurping), § air sparging, § in-situ bioremediation, § intrinsic remediation, § the “Waterloo Barrier"""" cut-off wall, § """"funnel-and-gate"""" systems, and § metal-enhanced oxidation. |
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Description: A Site Specific Risk Assessment (SSRA) was conducted to evaluate the risks to public health and the environment, and to develop site-specific clean-up criteria for the soil, groundwater and soil vapour at the site. The SSRA involved the consideration of five contaminants of concern, nine potential receptor groups and five potential contaminant migration pathways. XCG developed a Remedial Action Plan (RAP) that evaluated the possible remedial approaches including conventional approaches such as pump-and-treat and soil vapour extraction; and, emerging technologies such as Multi-Phase Extraction (bioslurping), air sparging, in-situ bioremediation, intrinsic remediation, the “Waterloo Barrier"""" cut-off wall, """"funnel-and-gate"""" systems, and metal-enhanced oxidation. The vacuum generated by the MPE system is so powerful that within the first week a small quantity (approximately 100 L) of free product chlorinated solvents was sucked out of the clay formation around the extraction well. This free product contributed to the initially high concentrations of chlorinated solvents in air stream. Since MPE is an emerging technology, its implementation was appropriately phased with a pilotscale demonstration followed by full-scale implementation. For the first four months the soil vapours were treated using a new technology called Photocatalytic Oxidation. This process uses UV light and a titanium dioxide (TiO2) catalyst to destroy the chlorinated compounds, and convert them to the basic elements of carbon dioxide and water. Due to the efficient recovery of the contaminant mass, the initially high concentrations quickly subsided. Afterwards Granular Activated Carbon (GAC) was used to treat both soil vapours and groundwater. The flow rate for soil vapour and groundwater are approximately 2 m3/min, and 18 L/min, respectively. So far over three pore volumes of groundwater have been removed from the core of the plume. |
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| Emissions/Byproducts: | n/a |
| Source of Information: | XCG Consultants (http://www.xcg.com/casestudies/Electrohome(Remediation).pdf ) |
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