Here's why:
* Alum is a flocculant: It causes the tiny clay particles to clump together, forming larger, heavier flocs.
* Flocculation: This process makes the clay particles settle more quickly to the bottom of the water, separating the muddy water into clear water and sediment.
* How it works: Alum reacts with the water to release aluminum ions. These ions attract and bind to the negatively charged clay particles, causing them to stick together.
Other substances can also be used for flocculation, but alum is a common and effective choice for clarifying muddy water.
