Biofuels I
In GCSE Biology, biogas which is mainly methane and carbon dioxide can be made by the anaerobic fermentation of waste materials.
A wide variety of microorganisms (e.g, bacteria and yeast) are involved in the digestion of waste materials. Microorganisms can be used to produce fuels (biofuels) by a form of anaerobic respiration, also known as fermentation. All oxygen must be removed for this to happen.
Biogas, which is mainly methane, can be made in this was using a wide range of waste materials and plant material that contain carbohydrate.
Waste from sugar factories and sewage works can be used to produce biogas on a large scale. Biogas generators are often located near to sewage works and sugar factories as this cuts down on transport costs.
Usually in GCSE Biology, smaller scale biogas generators can be used to provide the energy need for an individual family or farm. Waste is collected from kitchens and livestock and is digested by bacteria to produce biogas.
A biogas generator can provide enough energy for a small village or family. The biogas can be used for cooking on simple stove and for heating and lighting homes.
In GCSE Biology currriculum, the production of biogas depends on...
- The temperature of the fermenter (in cold countries the generator will have to be insulated to keep the bacteria warm enough to produce a good yield of biogas, in hot countries the generator will have to be kept cool (e.g, keeping it underground) so that the high temperatures don't kill the bacteria (denature their enzymes)
- The rate of fermentation
- The type of waste used
Advantages of biogas
- Can be thought of as a 'carbon neutral' fuel (releases the same amount of carbon dioxide that the plant material used for photosynthesis when it was alive)
- Good be LEDCs were electricity isn't widely available.
Disadvantages of biogas
- Still releases carbon dioxide when be transported etc.
- If any air gets into the generator the bacteria will respire aerobically, producing carbon dioxide, so the production of biogas will not be as efficient.
End of this part! (remember to read part 2)
Drafted by Gina (Biology)