Summary: the drinking water companies (1) changed their treatment process onsite to create a pure(r) by-product and (2) established a plant where this by-product is processed for reuse in their process and in other high-end applications. Both steps are unprecedented in the world.
Drinking water is softened in the Netherlands. It
– protects the transport lines;
– saves the use of chemicals cleaning showers glass,
– reduces energy consumption of (washing-)machines
– expands lifetime of (eg) kitchen equipment).
The softening process traditionally consists of (1) adding caustic soda to the raw water and (2) the precipitation of calcite on seeding material (sand). This results in softerning pellets with a core of sand and shell (97%) of calcite.
In order to create a better recyclable by-product, the drinking water industry changed their softening process using calcite instead of sand. This results in a more or less pure softening pellet with more possibilities to recycle.
Waternet, WML , Dunea and Brabant Water did an extensive research program to test seeding material made from their own by-product, it makes their process circular. The results were prodigious, this ‘Dutch calcite’ even worked better than quarry sand or calcite.
On April 13 ‘The Calcite Factory’ was opened in Amsterdam, where the sand-free softening pellets are processed by grinding, seeving, drying and sanitizing to (1) new seeding material (2) raw materials for (eg) plastic-, paper- or feed industry.