What describes the secondary treatment of water?

The secondary treatment of water is a crucial process in wastewater management that focuses on removing dissolved and suspended organic matter. The option that includes sedimentation, flotation, and chlorination accurately describes this stage.

During secondary treatment, biological processes are typically employed to break down organic contaminants. Sedimentation refers to the process where solids settle at the bottom of a treatment tank, allowing clearer water to rise to the surface for further treatment. Flotation involves introducing air or chemicals to facilitate the rise of solid particles to the surface, effectively separating them from the treated water. Chlorination is then used as a disinfection step to eliminate any remaining pathogens, ensuring that the water is safe before it is released into the environment or reused.

The other processes mentioned in the other options are either pre-treatment or specific physical processes. Coagulation and flocculation are part of the primary treatment aimed at removing larger particles from water. Bar screening is a preliminary step that removes large debris and solids before the water undergoes further treatment. Microfiltration, while effective in removing microorganisms and suspended solids, is typically associated with tertiary treatment rather than secondary, focusing on polishing the water before it is discharged or reused.