In-Situ Chemical Oxidation
In-Situ Chemical Oxidation
Residential Property UST Spill
Location: North Vancouver
When: 2020
Contaminant of Concern: Petroleum Hydrocarbons (LEPH), phenanthrene, pyrene
Impacted Media and Volume: 200 m3 impacted soil and groundwater
Tasks: Remediation Design, Blending, Field applications, Performance Monitoring
The Problem
An underground storage tank containing heating oil had leaked off-site onto a residential property and migrated under the building foundation. Impacts under the basement resulted in vapour intrusion in the basement and free product in property sumps.
The Approach
In-situ chemical oxidation (ISCO) program based on 2.5 meter injection radius of influence within the basement of the impacted property, as well as surface application and directional injection on the exterior property foundation. Injections were conducted using drive-points to target various depth intervals within saturated and unsaturated zones. Due to shallow groundwater levels at the property, a sump exists to artificially lower the groundwater and prevent flooding of the basement. TRIUM utilized this to increase the groundwater level, thereby creating a fully saturated treatment zone.
Over 7 days, advanced 24 injection points in the basement and 3 on the exterior of the property. A total of 20,104 litres of sodium persulfate was injected at the site. Blending is site specific following TRIUM’s TriOx process and utilizing appropriate activation products.
The Results
Confirmatory soil, groundwater, and vapour samples following injections met applicable guidelines
Minimal disturbance treatment option with 6-week treatment time-frame
Property owner provided clearance to return to home after remediation