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Why is quartz sand used in gravity sand-bed filters?
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filtration
Tap water filtration system.
Quartz sand is used in gravity sand-bed filters primarily due to its physical and chemical durability. It is an ideal filter medium because it is abundant, comparatively hard, and resistant to wear.1
Crucially, quartz is nearly insoluble in water and does not decompose, ensuring that the filter bed remains stable and effective during the filtration process. In gravity sand-bed filters, which are commonly used in city water plants, layers of uniform quartz sand are placed atop coarse gravel or crushed rock to effectively trap suspended particles as water passes through.123