What does anaerobic digestion involve?

Anaerobic digestion refers specifically to the biological process in which microorganisms break down organic matter in environments devoid of oxygen. This process is essential in sewage treatment as it helps to reduce the volume of organic waste and convert it into biogas—primarily methane and carbon dioxide—and a nutrient-rich digestate. The absence of oxygen is critical as it influences the types of microorganisms that thrive and the biochemical pathways they use for digestion.

This process not only facilitates waste stabilization but also contributes to renewable energy production through biogas, which can be harnessed for heating or electricity generation. Anaerobic digestion is widely used in treatment plants to manage sludge and reduce the environmental impact of wastewater treatment.

Other options describe different processes that do not align with anaerobic digestion. For instance, decomposing organic matter with oxygen present describes aerobic processes, while the use of heat to eliminate pathogens pertains to thermal treatment methods, and aerating water is linked to improving the quality of water by promoting aerobic conditions.