3) Decomposition

• . When organisms die or produce waste products, the dead material is broken down by organisms called decomposers.
• · Decomposers are certain types of bacteria and fungi.
• Decomposers need oxygen, moisture, a suitable temperature and a suitable pH to break down waste.
•  Decomposers break down dead waste by secreting enzymes, which partly digest the waste.
• The decomposers then take up the small, soluble food molecules.#
•  In a compost heap, gardeners try to provide optimum conditions for decay.
• The compost produced is used as a natural fertiliser for growing plants.
•  If waste is broken down in anaerobic conditions, methane gas is produced.
• Biogas generators can be used to produce biogas from waste for use as a fuel.

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