Wood Treatment Operation Closure

Support a lease closure at a wood treatment/preserving operation.

Environmental Consulting, Contractor Supervision

The Task:

Supervise the remediation of about 500 tonnes of impacted soil at a preservative formulation and wood treatment operation. Work was the result of a lease closure on the property, and the goal was to return the land to the property owners in acceptable conditions.

The Client:

Our client produces wood products treated with chromated copper arsenate (CCA) and alkaline copper quaternary (ACQ). They held a long-term lease on a half hectare property for over 25 years. (confidential client)

The Challenge:

CCA and ACQ had been formulated onsite. During the period of site operations, two documented accidental releases of CCA occurred at an interior tank farm. Remediation of these spills was completed; however, access constraints prevented complete remediation at the time of the spills.  Since site clean-up, soil quality standards have become more stringent, necessitating further remediation.  The remediation took place in long stretches of -20 degree °C  temperature weather.  A regulatory body became involved at the late stage of this project, citing concerns about groundwater contamination, with immediate concerns for downgradient drinking water sources.

The Solution:

Site remediation was undertaken inside the subject building beneath the concrete slab of the former production area. To access impacted soils beneath the building footprint, structural columns were braced with a system to allow excavation beneath strap beams and adjacent to column footings.  An x-ray fluorescence unit was used to delineate the impacted soil and guide soil excavation activities.

PGL’s project management expertise was highlighted through coordination with the property owner, and navigating the remediation in extreme temperatures, in a half occupied building, and under the building footings.

PGL addressed Ministry of the Environment and Climate Change (MOECC) concerns quickly. We designed a communication plan for neighbours with drinking water wells. Through leading edge sampling techniques, we were able to satisfy the MOECC that groundwater was not impacted, nor was it likely to be.

The Result:

The land was returned to the property owner in an acceptable condition. No further work was required to terminate the lease.  The MOECC was fully satisfied with our work and conclusions.