The Berkey® Phoenix Gravity filters form the heart of the Berkey purification system.
They are based on a combination of three complementary scientific technologies that make it possible to obtain drinking water of very high quality, without electricity and solely by gravity.

Please note that Berkey filters are not designed to be used with salt or softened water. Using the filters with salt or softened water will considerably shorten their lifespan and void their warranty.

Microfiltration

Microfiltration constitutes the first barrier against contaminants.

Each filter is composed of an extremely dense matrix, incorporating millions of micropores invisible to the naked eye. These pores allow water to pass through but are physically too small to allow the passage of many pollutants.

This process effectively retains:

→ pathogenic bacteria
→ cysts and parasites
→ sediments
→ solid particles and sedimentary minerals

Absorption (ion exchange)

Berkey filters also use an ion exchange process.

Certain contaminants, notably heavy metals such as lead, copper or chromium, are present in water in ionic form. These unstable ions are naturally attracted to the filter materials.

They are then permanently captured and bound to the filter, never ending up in the filtered water stored in the lower chamber.

Adsorption

Adsorption is based on an electrostatic phenomenon.

Inside the filter, an ionic barrier forms between the micropores. This barrier blocks contaminants even smaller than the pore size, including certain submicron viruses.

Thanks to their electrostatic charge, these particles are attracted against the internal walls of the filter and remain permanently trapped throughout the filtration process.

It is this capability that allows Berkey filters to be classified as water purifiers, and not merely as simple filters.

Gravity filtration and contact time

Berkey systems operate exclusively by gravity, without electricity or pressure.

Water takes several minutes to pass through the filters, ensuring a prolonged contact time between the water and the filter materials.
This high contact time considerably improves purification efficiency compared to pressure filtration systems.