After conducting a jar test, what does hazy settled water indicate?

Hazy settled water following a jar test indicates poor coagulation. During the jar test, which is a laboratory procedure that simulates the water treatment process, various coagulants are added to determine their effectiveness in aggregating suspended particles in water. Good coagulation leads to the formation of larger flocs that settle out of the water, resulting in clear supernatant water.

When the settled water remains hazy, it suggests that not enough of the suspended particles have been removed, indicating that the coagulation process was not effective. This could result from insufficient coagulant dosage, improper coagulant type for the specific water characteristics, or inadequate contact time for the coagulant to work effectively. The presence of hazy water demonstrates that while some flocculation may have occurred, it was insufficient to achieve the desired clarity, signaling a need to reassess the coagulation strategy.