Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste. When organic matter, such as food scraps and animal waste, break down in an anaerobic environment (an environment absent of oxygen) they release a blend of gases, primarily methane and carbon dioxide. Because this decomposition happens in an anaerobic environment, the process of producing biogas is also known as anaerobic digestion.
The Ecology of Biogas
Biogas is known as an environmentally-friendly energy source because it alleviates two major environmental problems simultaneously:
- The global waste epidemic that releases dangerous levels of methane gas every day
- The reliance on fossil fuel energy to meet global energy demand
By converting organic waste into energy, biogas is utilizing nature’s elegant tendency to recycle substances into productive resources. Biogas generation recovers waste materials that would otherwise pollute landfills; prevents the use of toxic chemicals in sewage treatment plants, and saves money, energy, and material by treating waste on-site. Moreover, biogas usage does not require fossil fuel extraction to produce energy.
Instead, biogas takes a problematic gas, and converts it into a much safer form. More specifically, the methane content present in decomposing waste is converted into carbon dioxide. Methane gas has approximately 20 to 30 times the heat-trapping capabilities of carbon dioxide. This means that when a rotting loaf of bread converts into biogas, the loaf’s environmental impact will be about 10 times less potent than if it was left to rot in a landfill.
Many Uses of Biogas:
Biogas can be produced with various types of organic matter, and therefore there are several types of models for biogas digesters. Some industrial systems are designed to treat: municipal wastewater, industrial wastewater, municipal solid waste, and agricultural waste.
Small-scale systems are typically used for digesting animal waste. And newer family-size systems are designed to digest food waste. The resulting biogas can be used in several ways including: gas, electricity, heat, and transportation fuels.
For example, in Sweden hundreds of cars and buses run on refined biogas. The biogas in Sweden is produced primarily from sewage treatment plants and landfills.
Another example of the diversified uses of biogas is the First Milk plant. One of the UK’s biggest cheese makers is building an anaerobic digestion plant that will process dairy residues and convert into bio-methane for the gas grid. New anaerobic digestion plants like these with fascinating stories keep popping up every day!