Coping with Adelaide's waste

By the early 1990s it was clear that Adelaide was quickly running out of landfill space. The problem was made more dire by the impending legislated closure of the Wingfield waste management facility on 31 December 2004. This facility had been operating for 50 years with limited environmental safeguards and had been the major waste repository for Adelaide. A new waste management facility - one with built-in environmental controls - was needed, and fast.

This presented a unique opportunity to develop a landfill project servicing theAdelaide metropolitan area. An extensive Environmental Impact Assessment process was embarked on to identify the location for a suitable new waste management facility. This required extensive time and capital investments as well as a commitment to the principles of a fully engineered landfill in order to receive the necessary government approvals. The Inkerman landfill site, located approximately 80 km north of metropolitan Adelaide, was subsequently identified and approved for the receipt of waste.

Owner of the Inkerman site, Waste Management Pacific SA (WMP), brought Renfrey Plant Hire on board to work on the project and together, through thorough planning and hard work, they had the landfill open for business according to a very tight schedule on the first working day of 2005.

Design of the Inkerman landfill has been based on making best use of available site resources. A key feature of this is the construction of a low-permeability liner developed using available site clays. Initial difficulties were faced in trying to use this material, but trialling different methods and refining construction processes allowed the creation of a lining system that exceeds the requirements of the South Australian Environment Protection Authority (EPA).

Being located in the driest state on the driest inhabited continent, and having limited access to potable water so as to minimise impacts on the local community, WMP commissioned Maunsell Engineers to carry out a study to confirm the suitability of using saline groundwater from the area with site materials to form the protective clay liner. WMP and Renfrey Plant Hire then incorporated this knowledge into site trials for determining suitable construction methodologies. This allowed the work to proceed using a previously under-used resource.

WMP has introduced an Australian first at the Inkerman landfill site through the incorporation of a mobile netting system into site operations which encapsulates the waste disposal area, preventing birds from accessing the waste as well as preventing the escape of litter.

The project was subject to strict independent geotechnical supervision and testing and had regular EPA site inspections throughout. Continual monitoring by WMP of potential environmental impacts has minimised effects from construction and operation of the landfill on the environment and local community.

Regular meetings have been held with community representatives throughout the project to allow information about site activities to be communicated to interested parties and any potential issues to be brought to WMP's attention.

As part of the Inkerman project, a resource recovery and waste transfer facility was established in metropolitan Adelaide to provide a cost-effective and efficient location for the consolidation of loads of waste, plus a high-efficiency transport system.

Waste Management Pacific and Renfrey Plant Hire achieved the rare honour of winning two South Australian Case Earth Awards for projects greater than $10 million for their role in constructing the new 17 million cubic metre landfill, which will provide a long-term, environmentally safe repository for Adelaide's waste.