Decay and Biogas

• The best conditions for micro-organisms to decay organic matter are:

  • Moisture- needed for the microbes to grow and multiply
  • Warmth- Increased temperature causes faster reactions as their is an increased rate of enzyme action
  • Oxygen- Micro-organisms need oxygen for aerobic respiration to release energy
• Farmers increase the rate of decay in a composter by:

  • Finely shredded waste to increase surface area
  • Holes in side to let in oxygen
  • Extra decomposers added
  • Warmth generated by microorganisms
  • Lid to prevent evaporation
• Biogas is produced in a generator (or a digester) using many different microorganisms to ferment carbohydrates in plant and animal waste.

  Biogas is usually made up of methane and carbon dioxide in a 7:3 ratio

  We can combust the biogas to release energy
• What are the two types of Biogas generators?

  Batch

  Continuous
• A batch generator is manually loaded with the waste and emptied by hand afterwards.

  It only runs for a short while each time
• A continuous generator is more automated and the waste is continuously fed in.

  The products made are removed at a steady continuous rate. It is used for more large scale products