Polyacrylamide is a synthetic polymer has several properties that make it useful for treating sewage and wastewater. It is commonly used as a flocculant, which means it aids in the aggregation and settling of suspended solids in water.

Here are a few reasons why polyacrylamide effective in sewage treatment:

1. Flocculation: Polyacrylamide is a high-molecular-weight polymer that can form large, sticky chains. When added to sewage, it binds with fine suspended particles and forms larger flocs (aggregates) through a process called flocculation. These flocs settle down faster under the influence of gravity or can be easily separated through filtration. This helps to clarify the water and remove solid impurities.

2. Improved sedimentation: By promoting flocculation, polyacrylamide enhances the sedimentation process in wastewater treatment. The larger and denser flocs settle more rapidly, allowing for efficient separation of solids from the liquid phase.

3. Reduction of turbidity: Turbidity is a measure of the cloudiness of water caused by suspended particles. Polyacrylamide aids in reducing the turbidity of wastewater by clumping the fine particles together, allowing them to settle out or be filtered more effectively.

4. Enhanced dewatering: Polyacrylamide can also improve the dewatering process in sewage treatment facilities. When added to sludge, it improves the consistency and solid-liquid separation. The formation of larger flocs facilitates the removal of water, making the sludge easier to handle and dispose of.

5. Versatility: Polyacrylamide is compatible with various chemical treatment processes employed in sewage treatment, such as coagulation, pH adjustment, and disinfection. It can work synergistically with other chemicals to improve overall treatment efficiency.

It is worth noting that polyacrylamide should be used judiciously to avoid any negative impact on the environment. Proper dosage, application, and adherence to regulatory guidelines are crucial to ensure its safe and effective use in sewage treatment processes.