National
Grid DC
Substation De-Construction

HELPING TRANSPOWER SAFELY REMOVE HAZARDOUS SUBSTANCES AND REUSE DE-CONSTRUCTION MATERIALS.

Client:        Transpower

Sector:       Private

Services:    Planning & Policy, Environmental, Ecology, Asbestos, Resource Consents

As part of Transpower's Benmore and Haywards Pole 1 Deconstruction Project, 4Sight was engaged to assist where historic operations had resulted in mercury contamination within the building.  There was asbestos-containing material (ACM) present, and in some areas the ACM was also contaminated with mercury. 4Sight’s innovative protocol meant asbestos and mercury removal in a manner that provided for worker health and safety and environmental protection.  It also allowed crushed concrete from the deconstruction project to be used as backfill material, which avoided disposal costs and a reduced carbon footprint.

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4Sight was engaged to help with the deconstruction of the Pole 1 buildings at the Benmore and Haywards substations, where historic operations had resulted in mercury contamination within the building.  There was asbestos-containing material (ACM) present, and in some areas the ACM was also contaminated with mercury.     

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Transpower wanted to deconstruct the Pole 1 building and use the concrete from the process as fill material in the Pole 1 building's basement; however, this couldn't proceed until the asbestos and mercury were removed and the client obtained consent.

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Drawing on our experience with national, regional, and district requirements, as well as international experience in ACM and mercury removal, we helped Transpower evaluate the human health and ecological risks and costs associated with various deconstruction, building reuse, and debris disposal scenarios for the project. We also helped the client reduce their potential liability by providing rigorous systems to document processes and maintain transparency in remediation activities.

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In our work on the project, we:

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• Developed an innovative protocol for mercury and asbestos removal and removal evaluation;

• Evaluated potential ecological and human health risks from reuse of cleaned concrete as on-site fill material;

• Developed a resource consenting strategy, which was a joint effort by 4Sight's Land and Water Quality team and our Planning and Policy team;

• Prepared consent applications;

• Presented information to Canterbury Regional Council;

• Provided recommendations for appropriate monitoring strategies to ensure environmental protection, including recommending guideline levels for surface water and sediment monitoring.

• Monitored contractor works against the protocol; and

• Evaluated air monitoring and other data.

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4Sight’s innovative protocol meant the removal contractor did not require containment for asbestos removal. By using our international contacts, we identified products that allow the safe removal of asbestos-containing tiles and adhesive without containment being required and with no airborne release of asbestos.  The protocol was approved by Environment Canterbury and WorkSafe NZ.  This innovation has resulted in a cost savings of over $100,000 at Benmore alone. 

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Consent was granted with guideline values for environmental protection, and the monitoring programme as presented in the application was approved. Being able to reuse deconstruction materials on-site will save Transpower tens of thousands of dollars, with the alternative being off-site disposal.