A digester is a device or system used to break down organic matter into simpler compounds by exposing it to heat, chemicals, and/or microorganisms. In biology, for example, a digester can refer to an enzyme that breaks down complex molecules in food during the process of digestion. In waste management or industrial processes, a digester is commonly used to break down organic materials such as sewage sludge, agricultural waste, or animal manure into biogas and fertilizer. The biogas produced can be used for energy production while the nutrient-rich fertilizer can be used in farming.