What is anaerobic digestion?

What is anaerobic digestion?

• A. A biological process that breaks down organic waste in the absence of oxygen to produce biogas.
• B. A chemical reaction that combines waste with oxygen to form ash.
• C. A physical sorting process to separate recyclables.
• D. A thermal process that melts plastics into fuel.

Answer: (A)

Anaerobic digestion is a biological process where microorganisms break down organic waste in the absence of oxygen to produce biogas, a mix largely made up of methane and carbon dioxide. This happens in sealed digesters where microbes perform anaerobic metabolism, converting complex organics into simpler compounds and releasing gas that can be captured for energy. The remaining solid and liquid material, called digestate, can be used as a fertilizer. This is different from processes that require oxygen or heat without microbes: combustion or oxidation needs oxygen and yields ash and CO2; physical sorting has no biological change; and thermal methods like melting plastics don't involve microbes or produce biogas. So anaerobic digestion is the oxygen-free, biological breakdown of organic waste that generates renewable biogas.

Anaerobic digestion is a biological process where microorganisms break down organic waste in the absence of oxygen to produce biogas, a mix largely made up of methane and carbon dioxide. This happens in sealed digesters where microbes perform anaerobic metabolism, converting complex organics into simpler compounds and releasing gas that can be captured for energy. The remaining solid and liquid material, called digestate, can be used as a fertilizer. This is different from processes that require oxygen or heat without microbes: combustion or oxidation needs oxygen and yields ash and CO2; physical sorting has no biological change; and thermal methods like melting plastics don't involve microbes or produce biogas. So anaerobic digestion is the oxygen-free, biological breakdown of organic waste that generates renewable biogas.