Diverting Organic Waste from Landfill - Creating Energy from waste
Biogas is basically produced as landfill gas (LFG) or digested gas.
Biogas digesters
Biogas digesters are air-tight tanks that use bacteria to break down the wet organic matter to produce biogas and also a semi-solid residue.
The biogas is used as a fuel for generating heat or electricity. Using biogas can assist keeping bacteria out of the environment and precious water resources and cut greenhouse gas emissions. Biogas plants can also improve sanitation, and the residue is useful as a fertiliser. Individual biogas systems are already benefitting several million households in Nepal, India, China and elsewhere. Larger systems are also used to process farm waste in Germany, and at sewage treatment works in the UK.
Creating biogas in a biogas digester
A simple biogas plant has a container to hold the decomposing organic matter and water (slurry) and another to collect the biogas.
There must also be systems to feed in the organic matter (the feedstock), to take the gas to where it will be used, and to remove the residue.
In our biogas plants, the slurry container and gas container are combined, so that the gas collects under a rigid dome over the slurry. As the slurry breaks down, the biogas which is produced pushes some of the slurry into a separate reservoir. When the biogas is taken off, the slurry flows back. A biogas plant needs some methane-producing bacteria to get it started.
Once the plant is producing biogas, the bacteria reproduce and keep the process going.
Cow manure is the best starter. The digester is fed regularly and the feed is mixed with water. Animal waste (specifically pig waste) needs longer to digest due to the high water content.
Biogas plants can work well for many years, provided that they are constructed well and checked regularly. If the plant is made from masonry, care must be taken to make sure that the structure is water-tight and gas-tight. For this reason a prefabricated system where the quality assurance takes place in a factory is preferred.
The Biogas Pro 6 is a six cubic meter micro biogas system with a self contained one cubic meter gas storage and a four cubic meter liquid digester zone. The system has been deliberately over engineered with extra thick tank walls and rounded flexible gas storage container to ensure a long life span.
Designed to take mixed waste it has fantastic retention ability and punches way above its weight class in terms of gas and organic fertilizer generation. Due to its factory built specifications this unit can be easily designed into a larger biogas grid putting a number of BP6 systems together in a semi-series system to allow it to take on larger amounts of waste.
Applications
Biogas can be used for electricity production on sewage works, in a CHP gas engine, where the waste heat from the engine is conveniently used for heating the digester; cooking; space heating; water heating; and process heating. If compressed, it can replace compressed natural gas for use in vehicles, where it can fuel an internal combustion engine or fuel cells and is a much more effective displacer of carbon dioxide than the normal use in onsite CHP plants.
The biogas system addresses a number of key challenges facing Southern Africa:
- Access to energy especially in rural areas
- Toxic waste and high cost of waste removal
- High cost of energy
- Vermin infestation
- Water scarcity
- High cost of fertilizer and the need for high nitrate fertilizers.
- Job creation needs
- Avoiding deforestation
The AGAMA Range of systems.
We presently offer five basic systems:
- AGAMA BiogasPro® 6 and 6D
- AGAMA BiogasPro® 3
- AGAMA BiogasPro® 3 Lightop
- AGAMA Smart Top
- AGAMA Rocket Laboratory Digester
