Preserving The Canadian Civil Defence / Emergency Preparedness History

Penhold Transmitter Bunker Remediation Project

If you haven’t already, you may want to investigate the Government of Canada’s “Federal Contaminated Sites Inventory” website at http://www.tbs-sct.gc.ca/fcsi-rscf/home-accueil-eng.aspx, with links to various publications and data, including Annual Reports.

There is a specific write-up about Penhold Transmitter Bunker Remediation Project, the custodian being Public Services and Procurement Canada, at http://www.federalcontaminatedsites.gc.ca/default.asp?lang=En&n=71C9FACF-1#penhold.

Here is a link to their contact page, http://www.tpsgc-pwgsc.gc.ca/comm/cn-cu-eng.html, to request information directly.

 

Penhold Transmitter Bunker Remediation Project

Name and Location: Penhold Transmitter Bunker, Alberta
Custodian: Public Works and Government Services Canada

The demolition of the bunker is being conducted using heavy machinery. The ground is covered with debris.

This is a former cold war–era communications bunker site located in farmland in southern Alberta.

During the decommissioning of the bunker in 2001, petroleum hydrocarbon (PHC)–impacted soils were discovered both under the bunker and alongside the structure. Since there is no documentation indicating management of fuel at the military site, it is difficult to determine the time frame and the quantity of fuel released into the environment.

Multiple investigative programs were undertaken to complete delineation and to determine the best option for remediation of the soils. Due to the large amount of overburden materials that were not impacted, the cost of removal of the clean soil to access the contamination was prohibitive. A multiphase extraction system was selected as the best way to remove the PHC product from the groundwater matrix and was installed at the site in 2004. This contract included hydraulic ground fracturing, installation of recovery wells and networks, and the supply and operation of a multi-phase recovery system to treat groundwater.

The system consists of six recovery wells installed six to nine metres below surface, connected to two recovery networks. The recovery wells consist of PVC pipes perforated with sand packs in the active zone. The infiltration gallery for return of treated groundwater consists of a trench excavated and backfilled with pea gravel, located approximately 20 m up-gradient of the plume. Two summer networks were added in April 2006 to enhance the system, and these additional networks vastly improved productivity of removal of product within the groundwater matrix.

The custom multi-phase extraction system consists of a steel container unit divided by a firewall into a small control room and a larger process room. The control room houses the electrical power and control components and the air compressor, and the process room contains the treatment components, including liquid ring pump, vapour-liquid separator, in-line filter, oil-water separators, and carbon vessels for water treatment. The process-room electrical equipment is equipped with explosion-proof components.

Fluid, vapour and air from the recovery wells are drawn into the network pipes and to the system by the liquid ring pump, and into the liquid-vapour separator. The vapour phase is discharged to the atmosphere. The liquid phase, consisting mainly of groundwater with diesel, is pumped to an oil-water separator. Floating product is skimmed off and transferred to two storage containers located in a lined area adjacent to the unit. The groundwater is then polished through two activated carbon vessels, and returned to the ground via the infiltration trench.

Between June 2004 and December 2008, over 4700 litres of diesel fuel were successfully recovered from the groundwater through the system. On-going monitoring of the site has revealed contaminant migration off-site, impacting the neighbouring property. As a result of this movement, soils exceeding Site Specific Target Levels identified through a risk assessment process will need to be excavated and removed from site. This final phase of the project will be tendered and carried out in late 2011.