A contaminated tract of land on the western side of Darwin Harbour has been brought back to life by Ventia's dedicated project team.
In 2015 we were awarded the Cox Peninsula Remediation Project in the Northern Territory by the Commonwealth Department of Finance. The remote land had been used by the Commonwealth for maritime, communications and defence purposes for 120 years.
The project team's aims were to restore the natural environment, make the site safe for future use and to work closely with the Traditional Owners of the land.
Working safely with dangerous contaminants
We removed asbestos, heavy metals and pesticides from the land across three separate sites: an Australian Communications & Media Authority (ACMA) site, a former Radio Australia site, and the Charles Point Lighthouse precinct, each of which came with its own challenges. We chose the most effective remediation methods and technologies for each situation, including thermal treatment, immobilisation, and disposal both on and off-site. For on-site disposal we designed and constructed a 30,000m3 on-site containment cell for the asbestos and treated wastes.
This complex project included:
- demolishing the Radio Australia transmitter and receiver compounds
- removing an extensive array of antennae infrastructure and underground cabling
- excavating, removing, treating and disposing of contaminated soil and waste tip sites, followed by reinstatement and rehabilitation
- removing and treating lead contaminated soils using a track mounted soil recycler (one of only two in Australia).
- designing, excavating, constructing, filling with inert material, and closure of a containment cell
- thermal treatment of contaminated soil, or off-site disposal to a licensed landfill
- monitoring emissions, dust and asbestos fibre
- groundwater and environmental monitoring to measure impacts of remediation works.
Engaging with the Traditional Owners
Working with the local Indigenous community was a strong focus for this project, and ultimately 35% of the project team was Indigenous. As part of our commitment to working with the Traditional Owners of the land, we engaged the Northern Land Councils Kenbi Ranger Group to deliver land management, heritage monitoring, site labour, transport and security services.
Ventia also extended training opportunities to each member of the Rangers, providing individuals with additional skills for the future. Courses included first aid, low voltage rescue, groundwater monitoring, plant operation competency verification, risk management and asbestos awareness and removal.Two Kenbi Rangers also visited our groundwater monitoring team in Victoria, learning how to periodically monitor the groundwater around the permanent containment cell at the site.
This collaborative approach saw Ventia and the Kenbi Rangers awarded Best Collaboration in Natural Resource Management in the NT Natural Resource Management Awards 2016.
Reducing environmental impact
Our commitment to protecting the local and global environment meant that during the project planning phase we identified and found ways to reduce our impact on the environment. Some of these included:
- constructing a 30,000m3 permanent on-site containment cell, which meant we could dispose of contaminated material close to the source, rather than transporting it 130 km and filling up the local landfill which was close to capacity. The cell was used for contaminated soils from various locations on Cox Peninsula, as well as building and demolition waste and asbestos. Excess crushed concrete was also placed in the cell. The cell was engineered to be impermeable, for long term and safe containment of waste materials.
- reclassifying soils with lower level contaminants for disposal rather than energy intensive on-site thermal treatment.
- replacing an existing bird nest in a tower destined for disposal which contained two resident ospreys (a listed species). We designed and constructed a replacement pole and nest and to everyone's delight the ospreys returned to take up residence in the purpose-built nest.
Watch the video to see how we did it.