Sand filters are a type of water filtration system that uses layers of sand to remove impurities and particles from water. They work by allowing water to flow through the sand, which traps dirt, debris, and other contaminants. This process helps to improve water quality, making it cleaner and safer for various uses, including drinking and irrigation. These filters are commonly used in swimming pools, aquariums, and wastewater treatment facilities. They are effective because the sand's small particles create a large surface area for trapping contaminants. Regular maintenance, such as backwashing, is necessary to keep the filter functioning efficiently and to prolong its lifespan.