Operations of Wastewater Treatment Plants Practice Exam 2025 – All-in-One Guide to Mastering Your Certification!

A clarifier plays a crucial role in the wastewater treatment process, primarily functioning to settle out suspended solids from the water. When wastewater flows into a clarifier, it is allowed to remain relatively still, allowing particles within the water to settle to the bottom due to gravity. This process is called sedimentation. The solids that settle form a sludge layer at the bottom of the clarifier, while the clearer water, known as supernatant, remains on top and can be further treated or discharged.

While aeration is an important step in wastewater treatment, especially for biological processes, it is not the function of a clarifier. Chemical treatment processes, such as adding coagulants or disinfectants, also do not take place in clarifiers. Additionally, while some clarifiers might have skimming devices to remove floating debris, their primary design and purpose are to effectively separate solids from liquids. Understanding the role of a clarifier is essential for operating wastewater treatment plants effectively and ensuring proper treatment processes are followed.