During anaerobic digestion, what is primarily being broken down?

During anaerobic digestion, organic matter is primarily being broken down. This process occurs in the absence of oxygen and involves the decomposition of complex organic compounds by microorganisms. The microorganisms feed on organic materials such as fats, proteins, and carbohydrates, producing biogas — primarily methane and carbon dioxide — as well as digestate, which can be used as a fertilizer.

Organic matter is a broad category that encompasses a wide range of substances, including food waste, agricultural residues, and other biodegradable materials. The breakdown of this organic matter during anaerobic digestion is crucial for reducing the volume of waste, stabilizing the material, and capturing energy in the form of biogas. This process not only helps manage waste but also provides a renewable source of energy and contributes to nutrient cycling in the ecosystem.

In contrast, while cellulosic materials can be part of the organic matter being digested, they are not the primary focus of anaerobic digestion. Excess nutrients are typically addressed through other processes in wastewater treatment rather than anaerobic digestion itself. Heavy metals, though they may be present in some waste, do not undergo breakdown in the anaerobic digestion process, as they are inorganic and do not decompose like organic matter.