Clarifiers
Clarifiers are tanks built with mechanical means for the continuous removal of solids deposited by sedimentation. They are commonly used in wastewater treatment plants and other industrial processes to separate solid particles from liquids.

Function of Clarifiers
The main function of clarifiers is to remove suspended solids from a liquid stream through the process of sedimentation. Sedimentation is the process by which particles settle to the bottom of a liquid due to gravity. Clarifiers provide a large surface area for the settling of particles and use mechanical mechanisms to facilitate the removal of settled solids.

Working Principle
The working principle of clarifiers involves the following steps:
1. Inflow of wastewater: The wastewater containing suspended solids enters the clarifier tank.
2. Settling zone: The wastewater is directed to the settling zone, where the velocity of the flow is reduced. This allows the solid particles to settle down under the influence of gravity.
3. Mechanical mechanisms: Clarifiers are equipped with mechanical mechanisms such as scrapers or rakes that continuously remove the settled solids from the bottom of the tank. These mechanisms help in preventing the accumulation of solids and maintain the capacity of the clarifier.
4. Effluent discharge: The clarified liquid, free from settled solids, is discharged from the top of the clarifier tank.
5. Sludge removal: The removed solids, known as sludge, are collected in a hopper or sludge pit at the bottom of the clarifier. The sludge is periodically removed from the clarifier for further treatment or disposal.

Advantages of Clarifiers
- Efficient removal of suspended solids: Clarifiers are designed to provide a large settling area, ensuring effective removal of suspended solids.
- Continuous operation: The mechanical mechanisms in clarifiers allow for continuous removal of settled solids, enabling uninterrupted operation.
- Flexibility: Clarifiers can be designed to accommodate different flow rates and handle a wide range of solid concentrations.
- Space-saving design: Clarifiers have a compact design, making them suitable for installations with limited space.

In conclusion, clarifiers are tanks built with mechanical means for the continuous removal of solids deposited by sedimentation. They play a crucial role in wastewater treatment and other industrial processes by effectively separating suspended solids from liquids.