3 Main Reasons AFM® Activated Filter Media will replace silica sand in all Rapid Gravity Filters in the Philippines

Silica Sand has been used for water filtration since 2000 BCE. Even to this day, most of the filtration systems use sand as one of the main filter medias.

One main way of filtering water using silica sand was thru a filter called slow sand filter. By forming a dirt and bacteria layer on top of it, Silica Sand was able to remove pathogens, and other bacteria from the water, making it safe and clean to drink.

As the industrial age began, cities started to grow and slow sand filters became a problem. They occupied a lot of space (slow sand filters can be as big as a football field) and were very slow to filter water, as the name implies.

This gave rise to Rapid Gravity Filters, which required lesser space and could filter water 5x-10x faster than slow sand filters. Although the production capacity grew, the need of maintenance also grew.

And as is its nature, silica sand became a great substrate for bacteria too. It started forming biofilm within the filter bed, which biocoagulated the bed and allowed unfiltered water to pass thru.

It's the same problem with silica sand today. The very bacteria which was perfect for slow sand filter, became a liability for rapid gravity filter.

This is where we introduce AFM® Activated Filter Media as a direct replacement to silica sand in all filters (except slow sand filters).

3 main reasons why AFM® will replace Silica Sand in all Rapid Gravity Filters:

1. No More Bio-Fouling and Bio-Coagulation: AFM® is coated using sol-gel method and comprises mostly of amber and green glass. The coating on and the oxides within these colored glass allows dissolved oxygen in water to form free radicals on AFM® grains, which destroy bacteria the moment it tries to stick to its surface.

This offers reliable filtration, and lesser backwash volume, saving thousands of pesos over the lifetime of the gravity filter.

2. Negative/Neutral Charge: AFM® comes in two charges: negative and neutral. AFM® standard has negative charge and is primarily used for removing precipitated iron, manganese and arsenic from deep well water. AFM® ng has neutral charge and is primarily used for removing hydrophobic material from water (hair, oils, lipids, microplastics).

This allows water treatment plants to tailor their rapid gravity filters according to different kinds of water sources.

3. 300x more surface area than Silica Sand: AFM® has more surface area, amplifying the charge (negative/neutral) of the media. This allows AFM® to filter down to 1 micron without the need of coagulants and flocculants.

This way, the water treatment plant can be assured of premium water filtration, and it also reduces post chlorination due to efficient and better filtration performance. 

This also allows filtration plants to operate at a faster flow rate, and make even smaller filter beds, simply by using AFM®. Higher turbidity can be handled more efficiently as well.


By allowing more water to be filtered, using lesser backwash water, doubling the performance and offering better water quality than silica sand, it's just a matter of time when all Rapid Gravity Filters will be replaced to AFM®. 

If you would like to know more about AFM® Activated Filter Media and see how we can help you, click here.

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