Garden Island Landfill Gas Management

Garden Island Landfill Gas Management is a landfill gas project located at Garden Island, approximately 16 kilometers northwest of the Adelaide CBD in South Australia. Registered in August 2015, the project is managed by the Urban Renewal Authority (trading as Renewal SA). While the registry listing does not specify an area, public reports indicate the site covers approximately 52 hectares.

The project operates under the Carbon Credits (Carbon Farming Initiative, Landfill Gas) Methodology Determination 2015. This methodology involves the installation of gas collection systems to capture methane generated by the decomposition of organic waste in landfills. Instead of venting into the atmosphere, the methane is combusted (flared) or used for electricity generation, converting it into carbon dioxide, which has a significantly lower global warming potential.

Garden Island is a reclaimed area situated within the Port River estuary, characterized by a coastal and industrial landscape. The region experiences a Mediterranean climate with hot, dry summers and cool, wet winters. As a closed landfill site in a sensitive estuarine zone, the "soil" consists of a clay and soil cap installed over legacy waste, surrounded by mangroves and marine waterways.

A notable feature of this project is its focus on "legacy waste" and the use of specialized technology. The landfill closed in 2001, and the project involved recommencing gas management using a "Lo-Cal" (low calorific) flare. This technology was required because the aging waste produces landfill gas with low methane concentrations (down to 12%), which standard flares often cannot effectively combust. The system was designed to mitigate fugitive emissions protecting the surrounding marine environment and nearby residents.