Design and Application of a Funnel and Gate Barrier System for PCB Remediation in the Canadian Arctic
Excavation of all PCB contaminated soils at the former military base at Resolution Island , Nunavut is not possible because some soil is trapped in the fractured bedrock or may be situated on very steep terrain that cannot be accessed for logistical and safety reasons. Much of the contaminated surface soil was stabilized by lichens and dwarf plants or by compaction since it has been undisturbed for many years. Excavation of this soil left a small amount of material in place, which is much more subject to erosion, particularly runoff. In order to control the mobilization of this material within the drainage system after excavation was completed, permanent barrier systems were proposed.
The application of geosynthetics as filters and sorbents in a funnel and gate barrier system were investigated. Prototype barriers were designed and constructed at the site and the performance studied. Laboratory research involved testing the suitability and efficiency of various materials to remove contaminants from water mixed with soil from the site areas under various conditions in order to mimic changes in temperatures, wind speed, water flow, filter thickness, clogging potential etc. In addition fundamental parameters such as partition coefficients, kinetic constants, permeability and permitivity were determined.
Barrier filter installation and potential filter materials (above), and an example finished barrier and continued sampling of granulated activated carbon (GAC) and gravel filter materials for monitoring purposes (below).
Barrier design schematic (below).
