How a softening system works in detail

Jan 31, 2024, 14:49:40

How is limescale removed from drinking water?
What properties does softened water have?
What happens when the water softening system is regenerated?

Our softening systems (also decalcification systems) work with the ion exchange process. This is a chemical process that removes the hardness causes calcium and magnesium from the water and replaces them with easily soluble sodium (component of salt).

How is limescale removed from drinking water?

Strictly speaking, limescale is just what remains when very hard water evaporates. It consists largely of calcium and magnesium. Our softening systems are installed in the house installation near the water meter. The hard drinking water, which is supplied by the waterworks, flows through the control valve from top to bottom through the ion exchange resin, which is located in the pressure tank of the system. In this area the water is softened. The exchange resin is structured in such a way that it absorbs calcium and magnesium ions and leaves sodium ions behind in the water.

Once the water has reached the lower part of the water softening system, it flows back up through a riser pipe. Special filter nozzles, which are attached to the top of the control valve and the bottom of the riser pipe, ensure that the special resin remains in the pressure vessel. This means that the lime remains in the pressure tank of the system and clean, lime-free water leaves the system into your house pipe.

(Image: Duplex water softening system )

What properties does softened water have?

The water that can be taken from a softening system has a water hardness of 0° dH or 0 mmol/l. There are therefore no more lime formers in this water (all other substances remain untouched). The pH value is unchanged compared to the input water, since the ion exchange process is a neutral exchange process. The sodium content increases by approximately 8 mg per liter and per degree of hardness removed in °dH. So if you previously had a water hardness of 20 °dH, then after softening you will have 160 (20 x 8) mg per liter more sodium in the water than before. The limit for sodium in drinking water is 200 mg per liter.

Completely softened water is suitable for drinking up to a certain degree of hardness. If the water hardness is very high (above 25 ° dH), a residual hardness must be left in the water if you do not want to exceed the limit for sodium. It is therefore possible to regulate the water hardness using an adjusting screw. For example, you can leave a residual hardness of 5 °dH in the water. This also has the advantage that you save some salt.

What happens when the water softening system is regenerated?

As soon as the capacity is exhausted, the exchange resin must be regenerated in order to be able to absorb new hardness formers. The control valve works fully automatically and initiates regeneration as soon as it is necessary. During regeneration, the system is flushed with salt brine. The exchange resin absorbs the sodium ions and releases the previously absorbed calcium and magnesium ions. The rinse water automatically ends up in the wastewater.

For individual systems, regeneration usually takes place every three days, exactly when the least water is needed (usually at night). Our duplex softening systems basically consist of two full-fledged softening systems and work in pendulum operation. This means that one softener column is always in operation while the second is being regenerated or is on standby. This means that soft water is available around the clock in our Duplex models. More about this: Single or double softening system (Basic vs Duplex)

In our shop you will find the right softening system for your household.