Silt-to-compost project wins Case Earth Award

Contaminated silt was excavated from Brownhills Creek, dewatered and sent off site for composting.

A project that turned contaminated silt that had built up in a South Australian creek into valuable compost has won an award for Environmental Excellence in the South Australian leg of the 2005 Case Earth Awards.

The award-winning project was carried out by a consortium of contractors comprising Flinders Bioremediation, Lucas Earthmovers and Jeffries Group. It involved excavating 3000 cubic metres of silt, sediment, rubble, organic matter and litter that had built up in a silt trap in Brownhills Creek. The material contained elevated levels of hydrocarbons and zinc.

Left untreated, this material would only have been suitable for sending to landfill at an estimated cost of about $500,000. Instead, the consortium developed a technique to remove and dewater the material before sending it off site to a recycled organics facility where it was turned into compost.

The project served as a trial of the application of composting technology to a unique problem. It is expected that this method will now be adopted more widely and for far larger projects.

The Case Earth Awards, sponsored by Case Construction Equipment and the Civil Contractors Federation (CCF) and now in their 12th year, recognise environmental reform in the construction industry.

Another project to win a state award in the Environmental Excellence category was the Inkerman Landfill, a 17 million cubic metre landfill developed by Waste Management Pacific.

All state winners are now in contention for the national honours, to be announced at the CCF National Conference Gala Dinner in Sydney during November.