Flocculation | Activated Sludge Process | Wastewater Treatment Plant

 Flocculation 

After quick mixing/coagulation, the flocculation process begins, which is performed by agitating the coagulated water continuously at a lower intensity but for a longer period of time.

The microflocs formed during coagulation come into contact with each other during this gentle mixing stage. Collisions between microfloc particles cause them to bond, resulting in larger, visible flocs known as pinflocs.

The floc size grows as a result of further collisions and interactions with inorganic polymers formed by the coagulant or the addition of coagulant aids. Macroflocs are then formed, and the water is ready for sedimentation once the floc has reached its optimal size and strength. 

The purpose of flocculation is to promote flocs to grow to a size where sedimentation and filtration can remove them.

Three factors influence the formation of flocs: 

• The effectiveness of coagulation, 
• The effectiveness of collisions in promoting particle attachment,
• Stable colloidal suspensions will not flocculate well, and 
• The rate of collisions. 

Detention Time 

Flocculation is a time-consuming process that has a direct impact on clarification efficiency. As a result, detention time is critical in the flocculation process. Choosing the right stirring time is essential for efficient flocculation. 

• The recommended detention time for floc formation is 30 minutes. 

1. It is required for the chemical reactions to take place. 

• The detention time required for optimal floc development is also influenced by the size and shape of the flocculation facility.