Water filtration has many filter options, from Anthracite to Limestone. Out of all filter media, sand, and carbon filters are widely used for water filtration and desalination. They both work to remove harmful particles from water, even though they function differently. The sand filter’s fine pores allow water to pass through and trap dirt particles slowly. Sand filters are universally used for various types of water treatment, including groundwater cleaning, rinsing water processes, re-circulating systems, and irrigation systems. In this blog, we will discuss sand and carbon filter media for desalination, along with their differences and benefits.

What is a Sand Filter?

These filters are essential parts of any water filtration or desalination procedure. They are filled with sand of different particle sizes so that nothing gets past it. Although the size of the sand filter depends on the liquid’s flow rate, it is usually placed at the beginning of the process. The water first passes through a sand filter before going into an activated carbon filter.

What is a Carbon Filter?

Activated Carbon filters are important for water purification as they remove chlorine, odors, volatile organic compounds, and unpleasant tastes from water. The use of activated carbon as a filter media results in its high porousness and extensive surface area. Heavy metals and impurities get absorbed or removed when passed through the filter. Finally, the water that leaves this filter is much cleaner than before.

How Does a Sand Filter Work?

The sand filter media works when water moves from the top of the tank through the sand to the bottom of the tank. High pressure is applied to make the movement smooth. As the water passes down, the sand grains collect particles such as dirt, debris, and body waste materials in them. Bit by bit, even the smallest particles are removed from the water as it passes through the sand, and the sand becomes denser and requires cleaning. 

To clean the sand filter media, it needs to be backwashed. It can be backwashed by both manual and automatic methods. In backwashing, the sand filter reverses the flow of water through it, so starting from the laterals at the bottom and working the way to the top while taking out the collected debris and particles with it. After the water goes through the whole sand filter, it is then sent to the waste instead of the pool. It only takes a couple of minutes to finish backwashing, so it doesn’t take much time and doesn’t need any labor. Once backwashing is completed, the system is rinsed, and the clean sand resumes filtering the water.

How is a Carbon Filter Different from a sand Filter?

Although both sand filters and carbon filters have similar construction, they still differ significantly. The main difference between them is the media they use for filtration process. For example, the carbon filter contains a large layer of activated carbon, while the sand filter has collection of sand with different particle sizes.

The carbon filter is perfect for removing whatever chlorine that was leftover after the water passes through the sand filtration stage. It is also great for removing molecular organic particles or elements that have managed to escape the previous stages of filtration. Activated carbon is great for eliminating any odors, colors, pesticides, or even organic components that may be present in water.

Bottom Line

Even though Sand filters are placed before activated carbon filter media, they still need to be cleaned and maintained in the same way. Factors such as the composition and pollutant concentration in the water, the airflow duration, and the water temperature and humidity affect the expectancy and efficiency of the filter media. For any inquiry related to sand and carbon filter media for desalination, get in touch with us at info@keiken.es.

Desalination systems are the pillars of freshwater supplies. They are an alternative to insufficient clean water production and natural causes of droughts. The system deploys reverse osmosis to purify contaminants like salt from untreated water. This process works by applying pressure pumps that effectively force the water through semi-permeable membranes.

Media filters consist of many filtration media, such as sand, gravel, or plant fibers. These media efficiently absorb and trap suspended particles in the water, removing impurities. In this blog, we will discuss how Keiken Engineering provides high-quality filtering media, which are perfect for use in the desalination, water, and wastewater management sectors.  

Top 5 Types of Media Filters

 Anthracite

Anthracite is a high-quality product with an NSF certificate and complies with drinking water standards. It is a great media filter for the treatment of water for human use.  The best applications for it are-

• Single-layer
• multimedia filters

Its angular shape, along with garnet, sand, or gravel, allows for high performance with reduced pressure drop. As a result, better filtration runs and longer intervals between backwashes.

 Zeolite

Always check if the zeolite is NSF certified. It is advised that it be used in drinking water treatment facilities, that desalinate brackish water and seawater. It can hold suspended particles as small as one micron in size, and it has a low carbon footprint.

The ability of zeolite to filter at greater speeds significantly reduces SDI and turbidity and extends the duration between washes.

Activated carbon

GAC stands out for its high carbon and iodine content, which enables it to obtain high adsorption performance. It can be mineral or vegetable-derived and has a rich internal porosity. The best part is the substantial free surface area for adsorption, activated by hot water vapour.

It is a very powerful adsorbent material for removing undesirable chemicals. It mostly eliminates organic matter and chlorine in gases and liquids.

 Garnet

Garnet must meet the most stringent requirements for drinking water treatment, wastewater cleaning, and industrial effluents. It is recommended to use it in dual filters with Anthracite or even single-layer filters. This is because it is well suited for the filtration of water with high metal concentrations.

Sand

Sand media is mainly used to treat drinking water. Silica sand follows a rigid classification to produce a particle size distribution. Additionally, several granulometries, from 0.5 mm to 5 mm, are there. 

It is ideal for any filtration device as it is completely natural, odourless, clean, and free of heavy metals and harmful compounds.

Gravel

Gravel needs to comply with certain standards for water treatment to make it fit for human consumption. Its physical qualities make it stand out as a product of the highest quality.

It is an affordable product for storing other filtering media, thanks to its outstanding mineral and composition features, such as Silica Sand, Anthracite, Zeolite, and Garnet.

Limestone

Always choose Limestone that contains more than 98% calcium carbonate. This substance is used in desalination plants following the reverse osmosis stage to remineralize water and during the post-treatment phase. Ensure that you choose the one that complies with the standards that govern its usage in the filtration process. 

The bottom line

After the reverse osmosis seawater desalination system, you have clean water for use.  Hence, it is clean, safe, and tasty water.  Modern desalination trends include the utilization of advanced technologies that improve the efficiency of removing pollutants. It further reduces costs and environmental impact. Among these technologies are different media filters that allow for the effective removal of pollutants.

To get more details about seawater desalination systems and how it works, contact Keiken Engineering.