Biogas is combustible gas derived from decomposing biological waste in the absence of oxygen (anaerobic digestion).
Biogas can be produced from wet or mixed organic waste streams (biomass). The anaerobic digestion conversion processes utilise natural occuring microbes and biochemical pathways to convert waste into biogas. During anaerobic digestion, around half of the carbon content of the biomass is converted to biogas, which can be directly used in a burner/condenser or fed into a gas engine to produce electricity and/or thermal energy (heat). The rest of the biomass becomes organic slurry which can be used directly as a fertiliser or separated into a liquid and solid phase to produce animal bedding/soil conditioner, liquid fertiliser and recycled water.
Bio-waste is collected from markets, restaurants, kitchens, gardens and farms.
The waste spends approximately three weeks in the digester where methanisation separates it into two parts:
• A solid part (digester sludge).
• A gaseous part (biogas).
Biogas generated can be used for cooking, lighting, heating or cooling. Biogas appliances, such as gas stoves or gas lamps are required for usage. Compared to other gases, biogas needs less air for combustion. Therefore, conventional gas appliances need to be modified when they are used for biogas combustion (e.g. larger gas jets and burner holes).
The byproduct can be directly applied to plants and gardens as a high quality organic fertilizer.
Biogas technology is a generic term for the technologies associated with the anaerobic digestion of organic waste (food waste, animal waste, sewage etc) to produce methane gas and an organic sludge (a recyclable by-product). Biogas technology is widely acknowedged as the best way to treat wet organic waste. Farm owners, food processors, waste managers and sewage treatment plant operators can all benefit from treating their organic waste streams with biogas technologies.
- Reduce the odours associated with intensive wet organic waste.
- Reduce offsite waste transport, handling and disposal costs.
- Provide opportunities for direct use of biogas for cooking, lighting, heating or cooling.
- Improve onsite water efficiency.
- Reduce the size and maintenance of existing effluent management systems.
- Extend the life of associated effluent infrastructure, such as septic tanks.
- Create new revenue streams.