Which of the following is a method of managing sludge?

The correct choice emphasizes various effective methods of managing sludge, which is the semi-solid byproduct generated during sewage treatment. Sludge management is crucial for maintaining the efficiency and environmental safety of wastewater treatment facilities.

Composting is a biological process that utilizes microorganisms to decompose organic debris found in sludge, producing a stable end product that can be used as a soil amendment. Anaerobic digestion is another biological process where bacteria break down organic matter in the absence of oxygen, resulting in the production of biogas and reducing the volume of sludge. Incineration, on the other hand, involves the burning of sludge at high temperatures, significantly reducing its mass and converting it into ash, which can be disposed of easily.

Each of these methods effectively reduces the volume and hazardous nature of sludge, thereby helping in its proper disposal or reuse, which is essential for environmental protection and resource recovery in sewage treatment operations.