What type of water treatment process uses PAC?

PAC, or powdered activated carbon, is primarily utilized in the coagulation process during water treatment. Coagulation involves the addition of chemicals to water to facilitate the clumping together of small particles and impurities. When PAC is introduced, it adsorbs organic compounds, taste, odor, and color from the water, helping to bind suspended solids. This significantly enhances the efficiency of the coagulation process by promoting the aggregation of particles into larger clumps, known as flocs, which can then be more easily removed from the water.

The application of PAC is particularly beneficial in treating water sources with high levels of contaminants, as it increases the rate of particle removal and improves the overall quality of the treated water. Thus, the reason for selecting coagulation as the correct answer lies in the role that PAC plays in promoting and improving the coagulation efficiency and effectiveness in water treatment processes.