TOOWOOMBA LANDFILL GAS PROJECT VISIT
Two members of GBSAN’s Resource Recovery team recently visited the Toowoomba Landfill Gas facility in Toowoomba. Councillor Nancy Sommerfield has spent 10 years advocating for, and progressing, the case for methane capture.
Stockpile of chipped material for use in capping landfill
We were warmly received on our visit and our host was very generous and informative.
The facility currently handles 80,000 tonnes of waste per annum and has been built to factor in an increase in tonnage as the population increases.
Toowoomba Regional Council (TRC) are saving their ratepayers around $600,000 per year in energy costs since the extracted gas is used to power the Wetalla Water Treatment plant which is sited next to the waste facility. In addition, a further $150,000 per year in carbon credits is generated.
Top of a capped landfill
Points to note:
No separation of waste takes place, thereby saving time and cost. Once the landfill is full it is capped using a 300mm thick layer of chipped waste from building materials and old furniture (think Ikea), pallets etc. These materials can’t be recycled due to various chemical residues and they are chipped on site.
Perforated tubes are sunk deep into the landfill and a vacuum is used to suck methane from the landfill.
Existing landfills can be fitted with vertical shafts but more recent, purpose built, sites operate more efficiently using lateral extraction via pipes laid every four ‘lifts’ (1 lift = 2.5m), feeding into vertical shafts.
The biogas, which is approximately 50% methane, is brought to the surface and then transferred via pipes to the water treatment plant nearby. The biogas is processed to leave only methane, used to power the generator for the plant. Excess electricity is sent to the grid.
It’s wonderful to see this and other visionary projects in our area coming to fruition. Let’s ensure we ask the hard questions of our local councillors and candidates prior to the local government elections in March.
Sue Frances and Philippa Hambleton
16 January 2024
Some of the gas extraction pipes
View of waste water treatment plant – seen from top of capped landfill