What does the term "clarifier" refer to in sewage treatment?

The term "clarifier" in sewage treatment specifically refers to a large tank designed to facilitate the settling out of solids from wastewater. In the treatment process, wastewater flows into the clarifier, where gravity causes the suspended solids to settle to the bottom, forming a sludge layer. This separation is crucial as it allows for the removal of solids, making the water clearer and preparing it for further treatment processes or discharge.

This separation technique is essential in the overall sewage treatment process, as it significantly reduces the concentration of solids in the effluent, which is critical for compliance with environmental regulations and for protecting aquatic environments. The clarified water that rises to the surface can then be treated further or discharged, while the accumulated sludge is typically processed separately.