How does a Berkey purification system work?

The purification elements are the heart of a Berkey system: water poured into the upper chamber passes through them by gravity alone, without electricity or pressure, and collects, filtered, in the lower chamber. According to the manufacturer, Black Berkey elements combine three processes.

Microfiltration

Each element is a very dense matrix, pierced with millions of micropores. Water passes through, but the pores are too small for many impurities: bacteria, cysts and parasites, sediment and particles.

Ion exchange

Some contaminants, such as lead, copper or chromium, are present in water in ionic form. They are attracted to the materials of the element and remain bound to them.

Adsorption

An electrostatic charge holds particles smaller than the pores against the inner walls of the element, including some viruses according to the manufacturer.

Gravity and contact time

Water takes several minutes to pass through the elements. This prolonged contact time between the water and the filter media is one of the strengths of gravity filtration.

What about Phoenix elements?

Phoenix Gravity elements, the new generation, work on the same gravity principle. They are certified to NSF/ANSI 42 and NSF/ANSI/CAN 372 in the Travel, Big and Royal Berkey, and are for mains water only. Their results are detailed in What does Berkey eliminate?.