In Brief: How To Soften Water
The various methods used in the process include ion exchange, chelation, reverse osmosis, and salt-free water softeners. The choice of method for softening water depends on factors like the amount of water you need to soften, the hardness of your water, among others.
What is the softening of water?
Softening of water refers to the process of removing salts of metals like calcium, magnesium, or iron. These metals often create insoluble deposits in water which can be seen as scales in boilers or tubs. Softening of water is done by adding such substances as lime, salt, or zeolite mineral.
Methods of water softening
There are many different types of methods and technologies that are used for the softening of water. Some of the most popular ones have been mentioned below-
Method 1: Reverse osmosis
Reverse osmosis uses a semipermeable membrane and reverse-flow technology to soften water. The water passes from a highly concentrated or saline solution through the membrane to a high purity stream on the opposite side of the membrane.
The membrane is used to filter out all unwanted elements from water, including calcium and magnesium ions that cause hardness, and only allow for the passage of water molecules.
Reverse osmosis method for the softening of water is extremely effective and leads to the removal of heavy metals, most salts, and solids from water.
There are, however, certain limitations to this method. One of them is that it leads to a lot of water wastage. To produce one gallon of softened water, a reverse osmosis system may require two or more gallons of water.
Additionally, they may also remove the healthy minerals and nutrients from the water in addition to removing the unwanted ones.
Reverse osmosis methods also require frequent maintenance and care. The storage unit for untreated water will require regular disinfection or may otherwise lead to bacterial growth. The entire system will also need frequent cleaning.
Reverse osmosis systems can also be a bit more expensive than other softening and purifying systems. They can cost anywhere between $500 to %1500 depending upon the type and size of the system among other factors.
Method 2: Ion exchange
The ion exchange procedure is used to exchange the calcium and magnesium in water for sodium ions. Sodium ions are provided to the water in the form of brine or dissolved sodium chloride salt.
The sodium ions are coated on an exchange medium. This exchange medium can either be resins or zeolites.
The sodium ions are loosely attached to the resin medium and as they are released in water, the calcium and magnesium ions take their place. Sodium ions are then released in water.
When using this method, it is necessary to frequently replace the resin mediums as they become coated with calcium and magnesium ions.
This process is known as the regeneration of ion exchange resins. To recharge the resin with sodium ions, a resin or softener is back flushed with salt brine solution.
During the back flush, this brine solution will replace the calcium and magnesium ions from the resin.
This process of water softening is considered advantageous as it enhances the lifespan of appliances and allows for reduced use of cleaning products like detergents.
This process, however, also has its limitations. When using a salt-based softener, the water can be used for drinking or watering plants due to its sodium content.
An increase in sodium intake can also lead to health issues.
Follow this quick link to understand how the ion exchange process is used for water softening:
Method 3: Chelation
Chelation is a chemical process for water softening.
Through this process, the combining of other chemicals with hardness causing ions, namely calcium and magnesium, is prevented, thereby preventing the formation of limescale.
The chelating agents combine with metal ions to form water-soluble compounds. EDTA is a commonly used chelator agent.
While chelating was earlier only used for large scale water softening, for instance for factory or industry use, it has now been made available for domestic and household purposes as well.
One of the massive advantages expressed concerning this method of water softening is that since calcium and magnesium ions remain in the water, they continue to provide the necessary health benefits when the water is consumed.
Additionally, there is no increase in sodium. It also does not require much maintenance and leads to almost no wastage of water.
However, this is not a long and sustainable solution. The chelating agent will last for a limited time only even as water continues to circulate in the system.
This will result in the re-activation of the hardness ions. Therefore, it is only recommended for water that will be consumed within one or two days.
Method 4: Template assisted crystallization (TAC) or salt-free water softeners
This process involves the use of ceramic polymer-based beads in an active media that acts as an anchor for calcium and magnesium ions.
The hardness ions integrate into the beads as crystals, making them grow larger on the media surface.
The accumulated crystals then disintegrate due to water movement and friction and are swept back into the flowing water.
These crystals then continue to flow into the plumbing system but do not attach themselves to any substance to form limescale.
The TAC or salt-free water systems are recommended for water hardness of about 25 GPG (grains per gallon), at a flow rate of 7 GPM (gallons per minute). This is a fairly new technology and has only recently been released for use at the domestic level.
TAC is a relatively expensive method for water softening. It can cost anywhere between $1300 to $1400. It also comes with the 5-micron sediment pre-filter.
Since the salt-free softener does not use sodium and potassium to soften the water, it can be consumed for drinking and other purposes without the use of expensive reverse osmosis filters.
This process also does not lead to any water wastage. It is an environmentally friendly process as it does not release any salt back into the groundwater.
However, if the water contains traces of oil or H2S, then this method must not be used.
Follow this quick link to see how salt-free softeners work:
Method 5: Boiling and Distillation
Boiling and distillation are some of the oldest known methods for softening hard water, and can easily be carried out at home. Boiling water precipitates the calcium carbonate out of the water, leaving the remaining solution soft.
Distillation, on the other hand, involves a 3-step process.
Water is first boiled, the rising vapor is then sent to a condenser where cooling water cools down the vapor, condenses it, and then store it. distillation is a fairly slow and energy-consuming process and is mostly used for industrial purposes.
Why do we need water softening
The hardness of water has become a common household problem in the US. Hard water leads to two common problems in the household- excessive use of detergent and soap, and the deterioration of appliances and different types of equipment.
Hard water commonly leads to the formation of lime-scale, the white staining, and deposition you may have noticed on your bucket or kitchen sink.
Anything that is washed with hard water, whether it is your utensils, or your hair and hands, will have the residual of chalky scale behind it. And while this may not seem like an immediate health concern, it does damage the things slowly.
The same is the case with your equipment and appliances. The chalky scale deposition on your water heater or filter will deteriorate and damage the efficiency of the appliance and eventually prevent them from functioning at all.
Hard water also leads to excessive use of detergent and soap for laundry or any type of cleaning purposes. Soft water will considerably reduce your consumption of detergent and soap, thereby cutting down your expenses.
To prevent all this damage, we need the process of water softening.
Benefits of softening water
There are many benefits of softening water. Soft water removes the existing scale within your heating system and prevents it from recurring. This saves the heater from damage and extends its lifespan.
It also leads to the saving of electricity, as water will get heated quickly and efficiently without the scales.
It similarly benefits other appliances and equipment. Softened water is also good for the plumbing system, as it helps in removing the scale and fixing the damage done by hard water.
Hard water has often been held responsible for hair and skin problems like dry scalp, eczema, and other conditions caused due to the dryness of the skin.
Soft water is usually considered better for skin and hair health. This is also because it does not require the use of large amounts of detergent or soap, thereby reducing dryness.
One additional benefit of using softened water is that it reduces the amount of soap or detergent being consumed.
The hardness of water caused due to soluble bicarbonates of calcium and magnesium is known as temporary hardness. Whereas, the hardness caused due to the presence of chlorides and sulfates of calcium and magnesium is known as permanent hardness. The addition of washing soda is often an effective way of removing both permanent and temporary hardness.
Baking soda is often used for softening laundry water. baking soda is sodium bicarbonate which is a surfactant. it is used to reduce the surface tension of a liquid. So, while baking soda will not essentially soften water (i.e, remove calcium and magnesium ions from water), it will make the water softer and smoother. This water is used for laundry and other similar purposes and not for drinking. to use baking soda, take ½ cup of baking soda and pour it into a tub of water.
Epsom salt, like other bath salts, can be used for softening hard water. On being added to water, Epsom salt releases sodium and potassium ions which replace the calcium and magnesium ions from water. calcium and magnesium ions are responsible for water hardness. This method is often used for softening bathwater but is only a temporary solution for hard water.
Only white vinegar can be used to soften water. Vinegar is naturally acidic and helps in neutralizing hard water as calcium is a very alkaline substance. However, vinegar should only be used to soften laundry water and water used for similar purposes. to use it, add ½ cups of vinegar to a tub of water.
It is usually recommended that you use a water softening system if the hardness of water is greater than 7 GPM or 120 mg/ L.
Water softening systems go a long way in preventing damage in your appliances and equipment, as well as the plumbing systems by preventing the build-up of minerals on them.
We hope that all this new information helps you in deciding which method you want to use for softening water.