Anaerobic digestion
Anaerobic digestion is where organic materials (food and garden waste) are converted into methane or 'biogas' and compost in the absence of oxygen. These processes take place in an enclosed building and involve the breakdown of organic material in a sealed vessel called a digester. This allows the biogas to be generated.
Any odours from the digester or composting are removed using a filter. Liquid left over at the end of the digestion process is recycled back into the digester.
For further information on how a typical anaerobic digestion process works, please download the information sheet below.
Information Sheet - Anaerobic Digestion - September 2012
Why has anaerobic digestion been selected as an acceptable technology option?
- Reduces greenhouse gas emissions and diverts significant amount of waste going to landfill: around 70% of waste (by volume)
- Produces marketable products: including compost and up to 1.8MW surplus of power from biogas generation (if exported from a 100,000 tonnes per annum facility) which is enough to power 2,700 homes
- Low risk of air and water pollution
- Low risk of odours
- Minimal risk of health consequences
- Net energy producer
- Well proven technology, with hundreds of commercial facilities in operation around the world, including Australia.
What are the disadvantages of anaerobic digestion?
- Markets for compost derived from municipal solid waste in Western Australia are still being developed
- Restricted to treating organic materials - other materials are removed for recycling or disposal
- Contamination of the organic material affects digester performance
- Biogas cleaning to avoid corrosion and odour can be problematic
Examples of anaerobic digestion facilities
Anaerobic facilities are operating successfully in Australia and overseas, particularly throughout Europe. Click on the link below for examples of anaerobic digestion in Australia:
AnaeCo anaerobic digestion facility at Western Metropolitan Regional Council in Shenton Park, WA