Garden Island Landfill Gas Management

Garden Island Landfill Gas Management is a landfill gas capture and combustion project located on Garden Island, approximately 15km 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). The site operates on a closed landfill that served as a major waste disposal facility for the metropolitan area between 1972 and 2001.

The project operates under the Carbon Credits (Carbon Farming Initiative, Landfill Gas) Methodology Determination 2015. This methodology credits the destruction of methane generated by decomposing organic waste. By installing a gas collection system involving deep extraction wells and perimeter "pin wells," the project captures methane that would otherwise migrate into the atmosphere. The gas is then combusted, converting potent methane (CH4) into less harmful carbon dioxide (CO2).

The project area consists of a capped landfill mound situated within a sensitive estuarine environment, adjacent to the Adelaide Dolphin Sanctuary and the Port River. The surrounding region is a mix of heavy industry and coastal conservation zones. The climate is Mediterranean/semi-arid, characterized by hot, dry summers and cool winters. The site's geology originally comprised estuarine muds and mangroves, but the project area itself is highly modified, covered by approximately 1.4 million tonnes of clay and soil capping.

A notable feature of this project is its use of specialized "Lo-Cal" (low calorific) flare technology. Because the landfill has been closed since 2001, methane concentrations are lower than in active landfills. The specialized flare installed can sustainably combust gas with methane concentrations as low as 12%, allowing the proponent to continue abating emissions and ensuring safety long after standard flares would cease to function.