You might be wondering how to remove salt from water if you have an ion-exchange water softening system. Ion-exchange systems produce soft water that contains a small amount of sodium.
Despite the fact that sodium can’t be tasted, some people prefer to remove it completely from their drinking water. Knowing how to remove salts from water can help you determine if augmenting your water softening system is right for you.
Soft Water and Sodium
In the process of water softening, sodium plays a key role. In a residential setting, hard water is dealt with using two primary methods: water softeners and water conditioners. Water conditioners change minerals so they won’t cause scaling, whereas a water softener removes the minerals in hard water and replaces them with sodium ions. Since these systems don’t contain sodium, they’re sometimes called salt-free water softeners. Here’s what you need to know about salt versus salt-free water softeners.
The process of ion exchange is what softeners use to remove hardness from water. Sodium plays a crucial role in this process.
Ion-Exchange
Mineral ions are picked up by water percolating through the soil and stone of the Earth’s crust. Mineral ions, most often calcium and magnesium, bind to water molecules. Once the water reaches your tap, it has been treated, but those treatments don’t affect its mineral content.
An ion exchange system can help here. Usually, these systems are installed where the main water line comes into your home after the water meter. There are at least two tanks in these systems: a brine tank and a resin tank.
In the resin tank, there are negatively charged resin beads attached to sodium ions. In the resin tank, hard water passes over the resin beads, attracting the positively charged mineral ions attached to the water molecule to the negatively charged resin. A solution of sodium ions is drawn from resin beads, which replace the mineral ions in water molecules. A positively charged sodium ion replaces a positively charged mineral ion to maintain ionic balance in the water molecule.
In time, the resin beads in the tank will accumulate a large number of mineral ions. Water will stop softening if these ions are not flushed from the system. The resin tank is flooded with salty brine from the brine tank in order to flush the system. Sodium ions replace the mineral ions in the resin once again after the salty water dissolves them. The mineral-containing brine solution is flushed down the drain, and the system is ready to start softening again.
The Impact of Sodium in Soft Water
Due to the amount of sodium in the soft water they produce, some people are skeptical about ion-exchange water softeners. Especially since the dangers of high-sodium diets have been discussed extensively over the last few decades, this is understandable.
In order to avoid any confusion, the soft water produced by these systems contains sodium (Na) instead of table salt, sodium chloride (NaCl). The sodium added to the water does not alter its taste. However, it is worthwhile to consider the impact of this sodium. For the average, healthy adult the sodium content in soft water poses little risk. The sodium content of the water produced by your system depends on how hard it is going into it. Sodium will be released in greater amounts from a water softener when water is harder than normal.
On the water hardness scale, for instance, water containing 10 grains of calcium carbonate per gallon (GPG) is considered very hard. Upon softening, this water contains only 74 milligrams (mg) of sodium per quart or 298 mg per gallon. Each gallon of soft water contains slightly more sodium than two slices of white bread or two cups of milk.
Removing Salt From Water
Sodium in softened water does not pose a risk to most people, however, some people prefer the sodium removed from their drinking water or require low sodium in their diets.
You should understand how to remove salinity from water if you still want the benefits of softened water but don’t want sodium in your drinking water.
A physical filtration system is the most common and effective way to remove salt from water. Reverse osmosis systems can remove salt and a variety of other contaminants from softened water.
Take a look at reverse osmosis systems, which provide a natural way to remove salt from water.
Reverse Osmosis System
To understand reverse osmosis, it is helpful, to begin with osmosis. Osmosis is all around us and is important for how our bodies function. Imagine two liquids on either side of a membrane. Different substances are dissolved in those liquids. The solution on one side of the membrane has a high concentration of a dissolved substance, while the solution on the other side has a low concentration.
Osmosis occurs when a liquid that has a low concentration of dissolved substances flows across a membrane to a solution that has a high concentration of dissolved substances. Until there is an equal amount of liquid and dissolved substance on both sides of the membrane, the flow will continue.
Unlike this natural process, reverse osmosis is the exact opposite. A good way to visualize reverse osmosis is through desalination, the process of removing salt from seawater. Reverse osmosis uses high pressure to force saltwater across a semipermeable membrane.
The pressure used in the system must exceed the osmotic pressure to force the water across the membrane. Water molecules can pass through the membrane, but sodium ions or many other contaminants cannot. Sodium is largely removed from freshwater on the other side of the membrane.
Benefits of Reverse Osmosis
For removing sodium from softened water, reverse osmosis is a highly effective and natural method. In addition, reverse osmosis systems significantly reduce the number of contaminants in water.
Reverse osmosis systems remove or reduce:
- Sodium
- Bacteria (Salmonella)
- Protozoa (Giardia)
- Viruses (norovirus)
- Nitrates
- Mineral and metal ions
- Perfluoroalkyl substances (PFAS)
A reverse osmosis system may also contain a sediment pre-filter and an activated carbon post-filter. Filters made of activated carbon are highly effective at removing many substances that give tap water a bad taste and odor. Among these are disinfectants like chlorine used in water treatment, chloramines, and volatile organic chemicals (VOCs). Using a reverse osmosis system that incorporates activated carbon filtration, you can be sure your drinking water has fewer contaminants and a filtered taste. You can learn more about Does Water Taste by reading our guide.
Can You Use Both Systems?
Definitely! Reverse osmosis and a water softener can be used together. This is how it works. Ion-exchange water softeners are installed at the point of entry (POE). The water line into the house is installed with ion-exchange systems, which provide soft water throughout the house.
You can install a reverse osmosis system at the point-of-use (POU) if you are concerned about the sodium content of soft water. You can do this at your kitchen sink or wherever you prefer to pour your drinking water.
A dual system setup allows hard water to enter your house and immediately enter the water softening system, where mineral ions are exchanged with sodium ions. In addition to removing sodium ions, other contaminants are also removed.
In this way, you can benefit from both soft water and water filtration. If you soften your water, you won’t have to worry about soap scum, scaling, and deposits that come with hard water. Reverse osmosis gives you gallons of filtered, clean water.
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