Water Softener
A water softener is designed to remove excess amounts of trace elements such as calcium, magnesium and other ions that exist in hard water. Hard water can cause a number of side effects such as lime scale, damaged plumbing and even corrosion to anything it touches. Most residential water softeners use an ion-exchange resin that is used to exchange the ions of calcium and magnesium for sodium ions.
Water softeners can be used to soften water, however, hard water does have a number of good things about it as well. You can actually get more calcium and magnesium in your diet by drinking hard water, which is extremely important. Hard water also reduces the amount of toxic metal ions in water such as copper and lead.
Resin exchange softeners work by passing the water that needs to be softened over a layer of resin. The negatively charged resin then binds to and absorbs all metal ions which are positively charged. The resin contains charged ions from the salt that’s added to this type of water softener. The water then replaces the ions on the resin with calcium and magnesium ions in exchange for the sodium ions through a chemical reaction. Only enough sodium is released in the water to exchange for any calcium or magnesium ions, so the amount of salt you use depends on how hard your water is.
Other resins are available that can remove other things such as carbonate and sulphate ions which can be captured using hydroxyl ions that are stored in the resin. Typically, both types of resin will be used in most water softeners to eliminate as many impurities as possible.
Eventually the resins will contain only calcium and magnesium ions. At this point the resin will need to be regenerate to continue to soften the water. Cationic resin, the type of resin used to remove calcium and magnesium, can be regenerated by flushing it with a brine created from salt loaded into the softener and water. Anionic resins, the kind used to remove sulphates, will typically need to be flushed with a lye solution to regenerate. The salts that are used to softener the water are eventually flushed into your septic or sewer system.
Other methods exist as well such as lime softening. Lime softening is also known as Clark’s process and is primarily used in Florida, Texas and the Midwest. Lime softening works by adding lime, also known as calcium hydroxide, to help neutralize the calcium and magnesium ions in the water. An additional benefit of this process is the removal of a wide variety of microorganisms and other biological matter from your water.
The addition of added sodium into water that’s been softened can be quite significant, especially with very hard water. For example, if you were to drink about 2L of water (equivalent to your recommended daily intake of water) that was softened from extremely hard water, you will have consumed about 500 mg of additional sodium.
The American Heart Association recommends that people who follow a severe salt restricted diet consume no more than 400 mg of sodium per day. They also say that no more than 10% of your salt intake should come from the water that you drink. If you are concerned with your salt intake levels, you can always plumb one faucet in your house that’s bypassed the water softener.
Water that hasn’t been softened can be quite beneficial to your health, providing you with additional nutrients and minerals your body needs. There are definitely some tradeoffs between softening and not softening your water. Most people only soften their water in cases of extremely hard water to help prevent the constant build up of lime scale and rust stains. Using a water softener can make your water somewhat less healthy when compared to water that hasn’t been softened, though the benefits can easily outweigh this.