Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted bonding with calcium ions. Soft water also extends the lifetime of plumbing by reducing or eliminating scale build-up in pipes and fittings. Water softening is usually achieved using lime softening or ion-exchange resins but is increasingly being accomplished using nanofiltration or reverse osmosis membranes.
Water softeners use methods that reduce the magnesium and calcium content present in the water. There are other water softeners that also reduce iron and manganese. These minerals are known to cause hard water, which is undesirable to most people due to various reasons. Though hard water may not be harmful to a person’s health, it can cause problems when it comes to cleaning surfaces. Softening your home’s water may address this problem.
Hard water contains metal ions that react when used with soaps by preventing them from making more lather and letting them leave a noticeable ring on surfaces, usually seen in the bathtubs that use hard water. Magnesium and calcium alike form deposits on areas where hard water is used for a long time. These deposits can also accumulate on things made from metal, like pipes, sink faucets, shower heads, pots and pans, and inside coffee pots. Extreme cases can even allow build-up to destroy equipment, since it acts as a thermal insulator that can possibly overheat metal tools.
Some of the most common forms of water softeners used in households are devices made from ion-exchanging resin. Water softeners are available in 3 main types, depending on the salt that they use, namely: hydrogen, sodium and potassium. They consist of a resin bed through which water flows. Since the resin has a negative charge, it binds to the metal ions with a positive charge found in hard water. Hydrogen, univalent sodium or potassium are particularly used in the resin, which exchanges with divalent elements such as calcium and magnesium ions. This means that when calcium and magnesium are removed from the water, they are replaced by hydrogen, sodium or potassium.
In the long run, these water softeners will get used up because they release the hydrogen, sodium or potassium molecules into the water as it flows through. However, the resin can be restored by allowing some brine to pass through the resin. There are different kinds of brine that can be used, based on the type of resin – like hydrochloric acid refreshing hydrogen, sodium chloride refreshing sodium and potassium chloride refreshing potassium resin.
After these brines have been used, they can result to problems in the environment when discharged in large quantities. For this reason, several regions need huge water softening plants to retrieve the brine so it can be properly disposed. Resin water softeners have this one side effect, which is, they allow water to be loaded with sodium, especially when the water is very hard from the beginning. During the process of water softening, they can add until 250 mg of sodium/liter to extra hard water.
There are three ways of regenerating water softeners: by means of a meter, using a timer or doing it manually. The most popular and most efficient type of water softener is meter regeneration. This is done by tracking the amount of water being used. Once it is set, the meter depends on the number of people using the water and the hardness of the water. Timer regeneration works on a set schedule, like for example, once a week. Though timer systems are cheaper than meter systems in terms of set-up, they are less efficient in using salts. On the other hand, manual regeneration is done by letting the user regenerate the softener whenever needed. It does not make use of any automated tracking device. While this type of softener is both cheap and efficient, it is only suitable for softening small amounts of water.