Soft water

Soft water is softened or descaled water. The opposite of soft water is so-called hard water, which contains a high concentration of magnesium (Mg²+) and calcium (Ca²+) ions. These components in cold water are essentially responsible for the calcification of all devices and pipes. Possible areas of application for soft water: There are numerous areas of application for soft water. Soft water is used practically everywhere that water pipes or water processing equipment need to be protected from calcification. Here are some examples of possible areas of application: power plants and district heating systems, hospitals and care homes, laundries, rinsing and washing water, process water, cooling water. Regarding the degree of water hardness, there are different levels in Germany: soft, medium, and hard. The exact water hardness is measured in °dH (German degrees of hardness), which essentially indicates the proportion of calcium and magnesium in the water. These are the hardness-forming agents, i.e., soluble compounds in the form of mineral salts that are responsible for the degree of water hardness. The amounts of these substances in groundwater vary depending on the environment. A value of less than 8.4 °dH is considered soft water, while a value between 8.4 and 14 °dH is considered medium-hard water. If the value is higher than 14, it is referred to as hard water. The degree of water hardness is of only minor importance for health. This is quite different for technical systems and installations. The mineral salts contained in hard water are deposited inside pipes and equipment, especially at higher water temperatures. This leads to higher water and energy consumption. In addition, repairs to the affected devices or systems can become more frequent. Hard water therefore causes additional costs that should be avoided.

Pipes in which water circulates become calcified. Water softening is carried out, among other things, to prevent the formation of limescale in pipes and electrical equipment used for wastewater treatment or water processing. The treatment of hard water into soft water takes place in special softening systems. In these systems, the calcium and magnesium ions responsible for water hardness are exchanged for sodium ions, thereby softening the water.

There are various methods for treating hard water. Ion exchangers are used very frequently. This is no coincidence, as water softening via the chemical process of ion exchange is currently considered the best option. However, there are other methods such as reverse osmosis or physical water softening.

Ion exchange

The water to be softened passes through an ion exchange column filled with special resin. As the water flows through this column, the calcium and magnesium ions in the water are filtered out by the resin layer. The resulting soft water then enters the building's water circuit or is made available at the appropriate extraction points. The advantage of this method is that the special resin is regenerable. To keep it receptive to the ions in the water, they are flushed out at regular intervals. This is an automatic process that can be carried out at night, for example.

Reverse osmosis and physical descaling

Reverse osmosis is a much less common water treatment method in which the water to be purified is pressed through a semi-permeable membrane at high pressure. In addition to heavy metals and other pollutants, minerals are also filtered out of the water. Another option for water softening is the physical method, which relies on electric or magnetic fields. However, the latter two methods are very rarely used for water softening.