What process involves using sand to filter out contaminants?

The process that utilizes sand to filter out contaminants is known as filtration. In water treatment processes, sand filtration is a common method used to remove suspended particles, bacteria, and other impurities from water. When water passes through layers of sand, the physical properties of the sand trap these contaminants, allowing cleaner water to emerge on the other side.

Filtration is a crucial step in both drinking water and wastewater treatment, ensuring that the water meets safety and quality standards before it is distributed for consumption or released back into the environment. In more advanced systems, sand filters may be used in combination with other treatment techniques to enhance their effectiveness.

In contrast, coagulation involves the addition of chemicals that promote the aggregation of particles, which can then be separated from the water but does not involve sand. Scavenging is often related to the removal of toxins or undesired substances, but is not specifically tied to the sand filtering process. Disinfection refers to the processes used to kill or deactivate pathogenic microorganisms, rather than filtering them out physically. Therefore, filtration stands out as the correct answer regarding the use of sand to remove contaminants from water.