| Softening water is often very helpful as it has a | | | | be damaging to the environment, especially in arid |
| number of benefits, in particular reducing scale build-up | | | | regions. Some jurisdictions prohibit such release and |
| and sometimes improving the taste. However, | | | | require users to dispose of the spent brine at an |
| softening it also has a certain effects on human health | | | | approved site or to use a commercial service |
| and also on the environment which are important to | | | | company. |
| consider. | | | | Most water softener manufacturers provide metered |
| The hard water to be treated passes through a bed | | | | control valves to minimize the frequency of |
| of the resin which contains sodium and potassium ions. | | | | regeneration. It is also possible on most units to adjust |
| As the water passes through the resin, the hardness | | | | the amount of salt used for each regeneration. Both of |
| ions are trapped in the resin and replaced by the | | | | these steps are recommended to minimize the impact |
| sodium or potassium ions which are released into the | | | | of water softeners on the environment. |
| water - effectively softening it. The harder the water | | | | In industrial scale water softening plants, the effluent |
| is, the more sodium or potassium ions are released | | | | flow from re-generation process can be very |
| from the resin and into the water. | | | | significant. Under certain conditions, such as when the |
| Effect on Humans | | | | effluent is discharged in admixture with domestic |
| For people on a low-sodium diet, the increase in | | | | sewage, the calcium and magnesium salts may |
| sodium levels (for systems releasing sodium) in the | | | | precipitate out as hardness scale on the inside of the |
| water can be significant, especially when treating very | | | | discharge pipe. This can build up to such an extent so |
| hard water. A paper by Kansas State University gives | | | | as to block the pipe as happened on a major industrial |
| an example: "A person who drinks two liters (2L) of | | | | plant in Australia in the 1980s. I certainly would not want |
| softened, extremely hard water (assume 30 gpg) will | | | | to be the person who had to clean that pipe! |
| consume about 480 mg more sodium (2L x 30 gpg x | | | | To Sum Up |
| 8 mg/L/gpg = 480 mg), than if unsoftened water is | | | | Although there are benefits to softening water, there |
| consumed." This is a significant amount, as they state: | | | | are also consequences that must be taken into |
| "The American Heart Association (AHA) suggests | | | | account, both human and environmental as discussed |
| that the 3 percent of the population who must follow a | | | | above. In my opinion, the benefits of softening probably |
| severe, salt-restricted diet should not consume more | | | | outweigh the disadvantages as long as one is aware |
| than 500 mg of sodium a day. AHA suggests that no | | | | that it does directly effect the quality of the water and |
| more than 10 percent of this sodium intake should | | | | consequently the minerals it contains. People who must |
| come from water. The draft guideline of 20 mg/L for | | | | have strict control over their diet (particularly their |
| water protects people who are most susceptible." | | | | sodium intake) need to be aware of this. Also, |
| Effect on Environment | | | | domestic water softening devices are very useful in |
| Over time the resins gradually lose their effectiveness | | | | preventing the hardness minerals which are removed |
| and must be regenerated by passing a concentrated | | | | causing hard water stains and limescale problems. |
| brine solution through them. Most of the salt used for | | | | They also do not have a significant impact on the |
| regeneration gets flushed out of the system and may | | | | environment compared to the much larger sized |
| be released into the soil or sewer. This process can | | | | devices that are employed in industry. |