Sand Media Filters: A Key Player in Water Treatment Processes   

Sand media filters are integral components in the water treatment industry, playing a crucial role in purifying and maintaining water quality. Their significance in various water treatment processes can be outlined as follows:

1. Removal of Suspended Particles: Sand media filters are highly effective in removing suspended particles from water. They work by allowing water to pass through layers of sand, which trap and remove particles, thus clarifying the water.

2. Versatility in Applications: These filters are versatile and can be used in a range of settings, from municipal water treatment plants to industrial and agricultural applications. They are particularly effective in treating groundwater, surface water, and wastewater.

3. Sustainable Water Treatment: Sand media filters are a sustainable option for water treatment. They require minimal maintenance and are energy-efficient, making them a cost-effective solution for long-term water purification.

4. Enhancing Water Quality: By removing contaminants and impurities, sand media filters significantly enhance the quality of water. This is essential for ensuring safe drinking water and for meeting the water quality standards required in various industrial processes.

5. Compatibility with Other Treatment Methods: These filters can be used in conjunction with other water treatment methods, such as chemical treatment and UV disinfection, to achieve comprehensive water purification.

How the Sand Media Filter Work?

The Filtering Process

Filtering with media filters, also known as depth filtration, is done by filtering water through a thick layer of graded particles, called the filter bed. These particles can be sand, gravel or other granular materials. The filtration degree depends on the effective size of the bedding and the water velocity through the filter. 
Raw water enters from the filter inlet (1) and percolates through the filter bed (2). Suspended materials come into contact and attach to the media particles. Clean water flows through the filtration nozzles (3) and out of the filter via the outlet valve (4). 
The gradual dirt buildup in the filter bed causes an increase in the pressure differential across the filter and when it reaches its maximum design value, a cleaning process should be performed. In automatic media filter installations a pressure differential switch senses the pressure differential and when it reaches a preset value, the self cleaning process begins.   

The Cleaning Process

Cleaning is done by backwashing; pressurized water flows in reverse direction - from the nozzles upwards, causing suspension of the filter bed, thus releasing the suspended matter from the bedding. The dirt particles are then washed out of the filter through the back-flush valve. In automatic media filters installations the cleaning process is done by the system's controller. When the pressure differential switch senses that the differential pressure across the system reached a pre-set value, a signal is sent to the flushing controller and the self cleaning process begins.