Cairns Regional Council - Portsmith Landfill Gas Project

Cairns Regional Council - Portsmith Landfill Gas Project is a landfill gas capture project located in the industrial suburb of Portsmith, approximately 4km south of the Cairns CBD in Far North Queensland. Registered in February 2014, the project operates on the site of the former Portsmith Landfill, which covers roughly 20 hectares. The site, having ceased acceptance of general waste around 2011/2012, now functions as a waste transfer station, while the surrounding area is characterised by industrial land use bordered by the ecologically sensitive Trinity Inlet.

The project operates under the Landfill Gas methodology, specifically targeting "legacy waste", waste deposited before July 2012. Landfill gas projects involve the installation of a network of wells and pipes to extract methane generated by decomposing organic matter. In this specific project, the captured gas is combusted using a flare. This process converts methane, a potent greenhouse gas, into carbon dioxide, significantly reducing its global warming potential.

Situated in the Wet Tropics, the region experiences a tropical monsoon climate with very high rainfall, particularly during the summer months. The landfill was originally constructed on a mangrove wetland, suggesting the underlying soil composition consists largely of marine clays, muds, and potential acid sulfate soils. Due to its proximity to the Great Barrier Reef Marine Park, the site’s closure and capping involved significant engineering to manage leachate and stormwater in this sensitive high-rainfall environment.

The project has been a key component of the Cairns Regional Council's emissions reduction strategy, reportedly destroying approximately 5,000 tonnes of CO2-equivalent annually. The closure and remediation of the landfill, which contains an estimated 1.7 million cubic metres of waste, garnered engineering awards for its design, which included a phytocapping layer to manage water ingress. The project successfully completed a Carbon Abatement Contract (CAC102466) with the Clean Energy Regulator.