What is the primary function of polyelectrolytes in water treatment?

Polyelectrolytes play a critical role in water treatment by serving as coagulant aids. Their primary function is to assist in the coagulation process, which is essential for aggregating suspended particles and aiding in their removal from water. Polyelectrolytes are charged polymers that interact with other particles in the water, promoting the formation of flocs—larger clumps of particles that can then be removed more efficiently through sedimentation or filtration.

In water treatment, when polyelectrolytes are introduced, they bind with coagulants like aluminum sulfate or ferric chloride to improve the efficiency of particle aggregation. This process is vital in treating water to maintain clarity and remove contaminants before the water is distributed for use. The enhancement of floc formation and settling time ensures that fewer chemicals are needed in the coagulant process, ultimately leading to a more cost-effective and efficient treatment plan.

Other options do not align with the primary responsibilities of polyelectrolytes in this context. While polyelectrolytes can influence other processes, their main contribution is through aiding coagulation, which is essential for effective water treatment.