Which type of filtration system uses a porous medium to remove particles?

A sand filtration system is specifically designed to use a porous medium, which in this case is sand, to effectively remove solid particles from water. The process involves passing water through layers of sand, where the larger particles can be trapped by the larger spaces between the grains, and finer particles are caught in the smaller spaces. As water flows through the sand bed, the filtration action occurs, allowing clean water to emerge at the bottom while retaining suspended solids and other contaminants within the sand.

Different filtration methods serve various purposes and operate on distinct principles:

• Reverse osmosis relies on a semi-permeable membrane to remove impurities from water, primarily targeting dissolved solids rather than larger particles.
• Activated carbon filtration utilizes activated carbon to adsorb chemical impurities, odors, and taste elements from the water rather than using a porous medium to physically trap particles like sand does.
• Microfiltration employs membranes to separate out particles based on size, typically filtering out microorganisms and larger particulates without utilizing a granular medium like sand.

Thus, while all these systems have their distinct applications and functions, sand filtration is specifically distinguished by its reliance on a granular porous medium for the physical removal of particles.