Which of the following is a method of sludge stabilization?

Sludge stabilization is a crucial step in wastewater treatment that reduces the organic content of the sludge, minimizes odors, and decreases the volume of materials that need to be managed. Anaerobic digestion is an effective method of sludge stabilization as it utilizes microorganisms that thrive in environments without oxygen. This process not only stabilizes the sludge by breaking down organic matter but also produces biogas, which can be captured and used as a renewable energy source. This transformation significantly reduces the mass of the sludge, making it easier to handle and dispose of.

While aerobic digestion is also a method of sludge stabilization, anaerobic digestion is often preferred in many wastewater treatment plants due to its energy recovery aspects and reduced oxygen requirements. Incineration, while it can be a method of reducing sludge volume, is primarily a disposal method rather than a stabilization technique. Filtration does not stabilize sludge; it is used to separate solids from liquids and does not significantly alter the characteristics of the sludge itself.