What is the Difference Between Sedimentation and Decantation

The main difference between sedimentation and decantation is that sedimentation is the overall process of particles settling to the bottom of a liquid due to gravity, whereas decantation is the separation of a liquid from solid particles by carefully pouring off the liquid, leaving the sediment behind.

Sedimentation and decantation are two related processes used to separate solid particles from liquid in a mixture.

Key Areas Covered

1. What is Sedimentation 
      – Definition, Features
2. What is Decantation
      – Definition, Features 
3. Similarities Between Sedimentation and Decantation
      – Outline of Common Features
4. Difference Between Sedimentation and Decantation
      – Comparison of Key Differences
5. FAQ: Sedimentation and Decantation
      – Frequently Asked Questions

Key Terms

Sedimentation, Decantation

Difference Between Sedimentation and Decantation - Comparison Summary

What is Sedimentation

Sedimentation is a geological and environmental process whereby solid particles settle down from a fluid medium, often water or air, and accumulate at the bottom of a container or a natural reservoir. This natural phenomenon plays a crucial role in shaping landscapes, forming sedimentary rocks, and influencing aquatic ecosystems.

In aquatic environments, sedimentation occurs as suspended particles, such as silt, clay, and organic matter, gradually settle due to gravitational forces. The settling process is influenced by factors like particle size, density, and the viscosity of the fluid. As particles descend, they create layers of sediment on the seabed or riverbed, contributing to the formation of sedimentary deposits over time.

Sedimentation is a dynamic and ongoing process that impacts the clarity and quality of water bodies. Excessive sedimentation can result from human activities like deforestation, construction, and agriculture, leading to sediment runoff into rivers and lakes. This can degrade water quality, harm aquatic habitats, and even disrupt the natural flow of watercourses.

Sedimentation vs Decantation

Beyond its environmental implications, sedimentation has geological significance. Over millions of years, accumulated sediments can undergo lithification, a process where loose particles are compacted and cemented to form solid sedimentary rocks like sandstone, shale, or limestone. These rocks often preserve a record of Earth’s past, providing insights into ancient climates, ecosystems, and geological events.

Understanding sedimentation is essential for managing water resources, mitigating environmental impact, and interpreting Earth’s history. In fact, scientists and environmentalists closely monitor sedimentation patterns to address issues related to erosion, habitat degradation, and water pollution.

Human activities can introduce additional chemical complexities to sedimentation. Runoff from agricultural areas, for instance, may carry fertilizers or pesticides, altering the chemical composition of sediment particles and impacting aquatic ecosystems. Industrial discharges can introduce heavy metals, altering sediment chemistry and posing environmental risks.

What is Decantation

Decantation is a simple yet effective separation technique used in chemistry to isolate a mixture’s components based on their differing densities. This process capitalizes on the principle that substances with varying densities will settle at different rates when left undisturbed.

In a typical decantation procedure, a mixture containing solid particles and liquid is allowed to stand, enabling gravity to exert its influence. The heavier, denser particles settle to the bottom, forming a sediment, while the lighter liquid remains above. This settling period is crucial, as it allows the separation to occur naturally.

Differentiate Sedimentation and Decantation

The success of decantation relies on understanding the specific gravity and insolubility of the components involved. It is particularly useful when dealing with heterogeneous mixtures such as suspensions or emulsions, where mechanical separation might be challenging or impractical.

One common application of decantation is in the purification of liquids. For instance, when muddy water is left to settle, the sediment settles at the bottom, and the clearer water can be carefully poured off, leaving the impurities behind. This method is fundamental in industries ranging from wastewater treatment to winemaking.

Additionally, decantation is employed in the laboratory for the separation of immiscible liquids. After mixing two liquids with distinct densities, allowing them to settle, and then carefully pouring off the upper layer, chemists can isolate the desired component.

Similarities Between Sedimentation and Decantation

  • Sedimentation and decantation are both processes used to separate particles from a liquid.
  • Moreover, both processes rely on the force of gravity to facilitate the separation.

Difference Between Sedimentation and Decantation


Sedimentation is a natural process where particles settle down due to gravity in a liquid, forming sediment at the bottom. Decantation, on the other hand, is a separation technique that involves carefully pouring off the liquid portion of a mixture, leaving the solid sediment behind.


Sedimentation occurs over time and is a passive settling process. It is not typically used as a deliberate separation method. Decantation, however, is a specific technique employed to separate liquid and solid components by pouring off the liquid while leaving the solid sediment behind.


Moreover, sedimentation often occurs in natural settings or in containers where particles settle over time. Decantation usually requires specialized equipment such as a decanter or separating funnel, allowing controlled pouring to separate the liquid and solid phases.

FAQ: Sedimentation and Decantation

What is an example of sedimentation?

Tea leaves settling down on a cup of tea is an example of sedimentation.

What is a mixture to which decantation could be applied?

Oil and water are such a mixture to which decantation could be applied.

Is salt and water an example of decantation?

Salt and water is not an example of decantation because decantation is typically used to separate solid particles from a liquid mixture. In the case of salt and water, salt dissolves completely in water, forming a homogeneous solution.


The main difference between sedimentation and decantation is that sedimentation is the overall process of particles settling to the bottom of a liquid due to gravity, whereas decantation is the separation of a liquid from solid particles by carefully pouring off the liquid, leaving the sediment behind.


1. “Sedimentation.” Wikipedia. Wikipedia Foundation.
2. “Decantation.” Byju’s.

Image Courtesy:

1. “Sedimentation Thickening Ponds diagram” By Eawag: Swiss Federal Institute of Aquatic Science and Technology Technical drawings: designport, Paolo Monaco, Zurich – eCompendium of sanitation systems and technologies:(CC BY 3.0) via Commons Wikimedia
2. “Dekantieren” By Andi schmitt – Own work (CC BY 4.0) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

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