Why use silica sand as filter media for water filtration and how does it work?
Silica sand has played a crucial role in water purification and filtration for many years. It is widely used worldwide, with four primary grades utilized for this purpose. The history of silica sand in water filtration dates back to 1804 when John Gibb designed and installed an experimental filter.
This pioneering filtration method underwent refinement over the subsequent years, leading to the installation of the world’s first public water supply by James Simpson for the Chelsea Waterworks company in 1829.
Water treatment practice,
later on, became mainstream after physician, John Snow, made the connection between the quality of the water as well as incidences of Cholera in the year 1845/1855. we have various products which will suit you.
In much of the developed world, the provision of good quality potable water is often taken for granted. But how does it actually work? Natural silica sand possesses a sub-angular to rounded shape, making it an ideal filtration media for capturing suspended solids in water. Its high silica content, durability, and hard-wearing nature allow for precise grading, enabling efficient filtering.
The grades of silica sand commonly used for filtration include 16/30, 8/16, 6/14, 14/25, 20/40, 18/8, 2/4, 3/6, 6/13, 13/19, and 14/25.
You can determine the silica grade by either considering the size range or using the Effective size (D10) and Uniformity Coefficient (UC).
Place the silica sand on top of the supporting layer of gravel within the filter vessel.
The filter allows incoming water to pass through the silica sand, effectively removing solids and debris. Silica sand’s unique properties make it a popular choice for water filtration in various applications, including swimming pools, leisure facilities, paper processing, power generation, chemical processing, and portable and wastewater treatment. In the market, you can find different types of silica sand filters, such as pressure filters.
These filters, which are commonly used in leisure applications, operate at a feed pressure of two to five bars.
The filter bed efficiently captures the majority of particulate solids, including even tiny particles, high up in the bed. Over time, as particulate solids accumulate, the pressure loss across the bed increases for a given flow rate. To address this issue, the filter bed undergoes backwashing, which involves reversing the flow to remove the accumulated particles.
During backwashing, the pressure loss or flow rate that exceeds acceptable levels prompts the cleaning process. This ensures that the filter bed remains effective and maintains optimal performance in capturing and removing contaminants from the water.
Rapid gravity filters
Water purification primarily utilizes rapid gravity filters, which are mainly employed at drinking water treatment works.
They do require smaller land areas in relation to the slow sand filters
and use the silica sand as well as other granular media
so as to remove the particles as well as impurities.
Read the following articles to know the more uses of silica sand: