Potable drinking water is a major challenge in our country nowadays as all the drinking water sources like rivers, ponds, and lakes have been subject to water pollution. Industrial waste and human excretion have been dumped into them for several years, causing the quality of the water to be degraded. Plus, at many places, groundwater is used as drinking water, and there is a high possibility that it would contain a higher percentage of minerals like calcium and magnesium. A more than preferred ratio of these minerals changes the nature of the water too hard. Water softening is the process of removal of these minerals from water to make it perfect for drinking as well as other purposes; the devices used for the process is called Water Softener.
About water softening
There are two majorly used scientific methods for softening water, one is through the ion exchange method, and the second one is reverse osmosis. Other less used methods are through Chelating agents, Lime softening, Distillation method, and washing soda method. Let us discuss them briefly.
Ion exchange method
This is the way most of the home appliances used to soften water. In this method, the calcium and magnesium ions are exchanged with sodium or potassium ions. This removed the hardness causing agents from water and add unharmful sodium and potassium in it. The devices use a resin-like substance that initially has all the sodium or potassium, but at the end is only left with calcium and magnesium. One needs to replace the resin from time to time as a recharge.
This method is now a day mostly used in industrial level RO Service as well as home-based water purification systems. In this method, water is pushed hard through a semi-permeable membrane. Since this action is done by immense pressure, it thus separates water molecules from hardness ions. The pore is large enough to allow water molecules to pass through but stops the calcium and magnesium ions. This membrane is the key to this process, and it needs to change from time to time.
These agents are mostly present in soaps. Shampoos so that the effect of hard water can be reduced while someone is using these products with hard water. For example, citric acid in soaps, phytic acids, and EDTA components are very commonly used in all the personal care products.
The simplest way of softening water is by boiling it and then capturing the evaporated water so as to condense them and retrieve the water in the purest form with no hardness. But this method is not used widely because it consumes a lot of fuel and is not energy efficient.
Washing Powder or soda method
In this method, we used home used washing soda, which has sodium and carbonate molecules. When treated with hard water, it changes the calcium and magnesium chloride and sulfate ions to their carbonates, which are evaporated, while setting the sodium ions with Chlorine and sulfides to form Sodium chloride and sodium sulfate.
We simply add the lime solution into the hard water, and a similar to ion exchange chemical reaction happens here as well but without any resins. It is a commercially viable way to soften water.
Importance of water purification and evolving methods
From all of the above, we have now understood how important the softening of water is and how we do it. But that is just a part of the whole water purification process. Because that is a multi-layered process where we remove chemical and biological contaminants and pathogens, solids that remain suspended, harmful gases. All of these should be removed to obtain pure drinking water. This process is carried out not only in-home based water purifiers but also at an industrial level in all the major sectors like pharmaceuticals, industrial appliances, mineral water plants, food processing, etc.
The methods have revolutionized as well, and nowadays, we use active carbons, flocculation chlorination, electromagnetic waves like UV rays in place of legacy methods sedimentation, distillation, and filtrations. The quality standard of pure drinking water is going high by high every year, and manufacturers are coming up with more advanced, economically viable, cost-effective water purifiers. But still, more than a billion people worldwide do not have access to pure drinking water.