Which of the following is a common method used in the primary treatment of wastewater?

In the primary treatment of wastewater, sedimentation is a common method used to remove solid materials and suspended particles from the wastewater. This process involves allowing the wastewater to sit in a large tank, where heavier solids settle to the bottom due to gravity, forming a sludge layer. This sludge is then removed for further treatment or disposal, while the clearer liquid above, known as supernatant, can move on to secondary treatment processes.

Sedimentation effectively reduces the bulk of solids and organic material in the wastewater, making it a crucial first step in the overall treatment process. While filtration, disinfection, and bioremediation are important in other stages of wastewater treatment, they are not typically part of primary treatment. Filtration involves passing water through a medium to remove particles, disinfection is used to kill pathogens, and bioremediation employs microorganisms to break down contaminants, often occurring after primary treatment has already reduced solids.