Settling of Solids in Water during Waste Water Treatment



During waste water treatment, various methods are used to remove solids from the water. One of the commonly used methods is settling, where solids settle down at the bottom of a tank or basin. The settling process is based on the principle of gravity, where heavier particles settle faster than lighter particles.



Types of Solids that Settle as Solid in Water



- Suspended Solids: These are solid particles that are suspended in water and can be removed through settling. Suspended solids include organic matter, bacteria, and other contaminants.

- Inorganic Solids: Inorganic solids such as sand, silt, and clay also settle during waste water treatment. These solids are heavier and settle down at the bottom of the settling tank.



Process of Settling Solids in Water



- Cohesive Forces: The settling process is influenced by cohesive forces between solid particles. These forces determine how fast solids settle in water.

- Retention Time: The longer the retention time in the settling tank, the better the settling of solids. Adequate retention time allows the heavier solids to settle down completely.

- Particle Size: Smaller particles take longer to settle compared to larger particles. Controlling the particle size distribution can improve the settling efficiency.



Advantages of Settling Solids in Water



- Efficient Removal: Settling is an efficient method for removing solids from water, including both suspended and inorganic solids.

- Cost-Effective: Settling is a cost-effective method compared to other advanced treatment processes.

- Environmentally Friendly: Settling does not require the use of chemicals, making it an environmentally friendly treatment method.



In conclusion, settling is an effective method for removing solids from water during waste water treatment. By understanding the types of solids that settle and the factors influencing the settling process, wastewater treatment plants can improve the efficiency of their treatment processes.