Final answer:
Anaerobic digesters carry out anaerobic digestion of wastewater, breaking down organic material without oxygen, reducing sludge volume and odors, and producing methane for biogas.
Step-by-step explanation:
Anaerobic digesters are sealed reactors used to perform anaerobic digestion of wastewater. This process involves the breakdown of organic material by microorganisms in the absence of oxygen. Sludge digestion is a key step where sewage sludge from the bottom of a sedimentation tank undergoes bacterial digestion to reduce volume, odors, and pathogens. One byproduct of this process can be methane, which is utilized in biogas production to generate electricity.
During the anaerobic respiration, certain microorganisms can survive in oxygen-depleted environments by using different final electron acceptors, such as nitrate or sulfate. This form of respiration is crucial in the treatment of wastewater as it enables the stabilization of sludge under oxygen-free conditions. Post digestion, the treated material can be safely disposed of or used as fertilizer, following careful testing for contaminants.