Dandenong Treatment Plant C.A.L.M. (Capped and Lined Mound)

Location: Greens Road, Dandenong, VIC
Client: Melbourne Water
Value: $9.1m

The Details

Following on from Goldsmith’s successful completion of the Dandenong Treatment Plant Remediation project, Goldsmith was engaged by Melbourne Water to undertake the next phase of the project, which included the construction of a Capped and Lined Mound (C.A.L.M.) with the 600,000m3 of contaminated material stockpiled during the remediation project.

The CALM design incorporates a compacted clay and LLDPE Base Liner and a compacted clay and LLDPE membrane for the cap. It consists of 6 Cells, totaling 87,000m2 in area at the base and 89,000m2 of geomembrane in the cap.

Other features of this relatively complex design, include a gas collection system, leachate collection system and surface drainage infrastructure. The material tracking system developed by Goldsmith for the remediation project was further used to track each load of the 600,000m3 of contaminated material into its final position. This system allows waste from any area of the original treatment plant site to be located in its new position.

Goldsmith contributed significantly to the design of the CALM in the following areas:

  • optimising use of available materials in the drainage layer, resulting in cost savings and creation of 9,000m3 of repository air space
  • replacing capping filter sand with a geocomposite drain saving cost
  • eliminating 50% of subsurface pipes
  • saving 26,700m3 of landfill air space
  • consulting closely with client and designers to replace over-specified items for various components and sourcing equivalent lower cost replacement