Anaerobic Digestion & Biogas: Energy from Organics

When bacteria break down food and farm waste without air, they make methane-rich biogas and a fertiliser — a double win.

Anaerobic digestion (AD) is a process where microorganisms decompose organic matter in an oxygen-free tank. The output is biogas (mostly methane and CO₂) that can be burned for heat and power, plus a nutrient-rich digestate useful as fertiliser.

What Feeds an AD Plant

• Food scraps and supermarket waste.
• Animal manure and crop residues.
• Sewage sludge and some industrial organic by-products.

AD vs Composting

Both handle organics, but AD captures energy as biogas while composting mainly makes soil. AD suits wet, energy-rich feedstocks; composting suits garden and yard waste. Many systems do both — digest the wet fraction, compost the rest.

Why It Helps

Instead of rotting in a landfill and emitting methane uncontrolled, the same organics are digested in a sealed tank where the gas is captured and used. That converts a climate problem into fuel and fertiliser.

Related Reading

Compare with home composting and waste-to-energy, and see how rural areas use local treatment.

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