Sand from water is separated by sedimentation and decantation.

Sedimentation:
- Sedimentation is the process in which solid particles settle down at the bottom of a liquid due to the force of gravity.
- When sand is mixed with water, the sand particles being heavier than water, settle down at the bottom of the container due to gravity.
- This settling down of sand particles is called sedimentation.

Decantation:
- Decantation is the process of separating a liquid from a solid by carefully pouring off the liquid without disturbing the solid at the bottom.
- After sedimentation, the clear water above the settled sand can be carefully poured off or decanted from the container, leaving behind the sand at the bottom.

Steps Involved in Separating Sand from Water:
1. Mixing sand with water: The sand is mixed with water to form a mixture.
2. Allowing the mixture to stand undisturbed: The mixture is left undisturbed for some time.
3. Sedimentation: During the standing time, the sand particles settle down at the bottom of the container due to gravity. This is called sedimentation.
4. Decantation: After sedimentation, the clear water above the settled sand can be carefully poured off or decanted from the container, leaving behind the sand at the bottom.
5. Collection of sand: The sand that remains at the bottom of the container can be collected for further use.

Advantages of Sedimentation and Decantation:
- Sedimentation and decantation are simple and effective methods for separating sand from water.
- They do not require any special equipment or chemicals.
- Sedimentation and decantation can be performed easily at home or in a laboratory setting.
- These methods are cost-effective and do not require much time.
- Sedimentation and decantation do not produce any harmful by-products or waste.

Limitations of Sedimentation and Decantation:
- Sedimentation and decantation may not be suitable for separating very fine particles of sand or when the sand particles are mixed with other materials that have similar densities.
- In such cases, other methods like filtration or centrifugation may be more appropriate.