What is the primary function of a clarifier in wastewater treatment?

The primary function of a clarifier in wastewater treatment is to allow solids to settle out of wastewater. In this process, the wastewater flows into the clarifier, where it is held in a large tank. The reduction in flow velocity allows heavier solids, such as suspended particles and organic matter, to settle to the bottom of the tank, forming a sludge layer. This sedimentation process is crucial as it helps to separate solid waste from the liquid phase, resulting in a clearer effluent that can be further treated or discharged.

The clarifier is an essential component in the treatment process because it reduces the concentration of suspended solids in the wastewater, which is necessary for effective biological treatment or further processing. The settled solids can then be removed periodically for proper disposal or treatment, which is critical for maintaining the effectiveness of the treatment facility.

The other options refer to functions that do not align with the primary role of a clarifier. Filtering chemical pollutants is typically done in more advanced treatment processes, aerating the water involves adding air to enhance biological treatment, and injecting nutrients is part of enhancing microbial activity in biological processes, but none represent the core function attributed to a clarifier in wastewater treatment systems.