Borehole water softener

Softening water from a well: why to soften water, as well as methods of water softening

What interesting things you will learn from the content of this article:

1. Why to soften water

2. Methods of water softening

2.1 Boiling method

2.2 Ion exchange method

2.3 Reverse osmosis method

2.4 Reagent method

3. Comparison of softening methods

Initially, it was well water that was considered the cleanest and devoid of any impurities. But this fact has long been irrelevant. Well water, even if it is artesian, just like any other, is subject to contaminants. They appear in the process of passing groundwater between the layers of the earth. Many factors can increase the concentration of contaminants. One of them is pesticide treatment Absorbed into the ground, harmful substances penetrate quite deeply, ending up in the path of groundwater. The presence of contaminated groundwater sources is also another reason. As a result, the composition of water from a well can be dozens of times more harmful than tap water. It may contain not only calcium and magnesium salts, but also many other impurities, including organic contaminants. For the most part, water from a well is used in settlements or country houses and is used for cooking, irrigation, drinking. It is necessary to accurately select the method of softening, while not making the water too soft.

1. Why soften water

So, as we have already found out, well water often carries a lot of harmful elements. One of these are hardness salts. Their presence in the water is quite easy to determine. The easiest way - boil the water and the scale will remain on the bottom. The greater the concentration of hardness salts in water, the more damage it can cause. If you use such water for food, the body suffers. Salts are deposited in the joints and vessels. There can be formed growths on bone tissue. For household appliances, the presence of scale leads to imminent breakdown. The fact is that hardness salts form a scale that coats the heating element, reducing heat conductivity. This applies to kettles, washing machines and dishwashers. This results in increased electricity consumption. Hardness salts are also dangerous for pipes. They settle on the walls, clogging them. As a result, all household appliances and plumbing must be replaced. Scale removal by improvised means in this case is ineffective. It tightly adheres to the walls and heating element and it is difficult to remove it without using chemicals and without mechanical damage. In the industrial segment hard water is not allowed to be used at all. Any water must strictly obey the norms of SanPin. For example, in some areas of production, even a minimum concentration of hardness salts is unacceptable. Not only can harm the product, but the equipment will also suffer. And in industry, its replacement will be very expensive. In this case, production can completely stop. Therefore, to avoid such problems, water is softened. There are several ways to do this.

Fig. 1 Consequences of hard water in heating systems

2. Methods of water softening

Some softening methods are suitable only for industrial production. Others are oriented towards the domestic sector. In any case, the initial chemical composition of the water and the purpose of the system play an important role. Each method has advantages and disadvantages. It is important at the first stage of choosing a method to determine the requirements and based on this information to take into account all the nuances of softening. The chosen method must effectively cope with the task at hand. Uninterrupted operation of the system is also one of the key factors when choosing a softening method.

2.1 Boiling method

One of the earliest methods of removing hardness salts, which is known to everyone. Today, with modern water treatment plants, it already seems archaic. However, in some situations it is boiling that helps to get rid of hardness salts and get usable water. Of the disadvantages of the method can be distinguished by the fact that it removes only temporary hardness of water. And is suitable for cleaning a small amount of water. The essence of the method is boiling. When water is heated to a certain degree, calcium salts precipitate, forming flakes of scale. On a large scale, the method is extremely inappropriate, because at such a capacity, water heating must occur constantly. And this is not only a waste of time, but also of electricity. Boiling is used in camping trips and when it is necessary to purify a small volume of water. This method is ineffective in large production facilities due to high productivity.

Fig. 2 Boiling method

2.2 Ion exchange method

This method is suitable for both domestic and industrial applications. Household softening systems based on ion exchange are more compact and easier to use. The main purifying element is the ionic resin. It is filled with sodium ions. When water passes through the filter, hardness salts are replaced by sodium ions, which are completely harmless. Over time, the resin becomes clogged with calcium and magnesium ions and must be cleaned. For this purpose, a saline solution is used. The filter is washed with salt concentrate and re-saturated with sodium. The solution is discharged into the drain, having previously been cleaned. Since it is not quite rational to install such a system with a solution tank and a disposal system for home use, the ionic resin is placed in a cartridge. Therefore, when regeneration is necessary, the filter is simply changed. In industrial production everything remains the same. The regeneration system makes it possible to extend the service life of the filter. If necessary, sensors can be installed to monitor the system and automatic regeneration. But this design is quite expensive. And if the household equipment is still more or less affordable, industrial installations are not cheap at all.

Fig. 3 Filter softener by ion exchange method.

2.3 Reverse osmosis method

The reverse osmosis method is based on membrane purification. For this purpose, special membrane filters are used, which consist of many small cells. And they retain calcium and magnesium salts. Pressurized water is fed to the filter and the flow is divided into two parts. One of which is cleaned and passes on, and the second rinses the filter and goes down the drain. The membrane is very sensitive to external influences and chemical elements. Therefore, it is necessary to install primary filtration, which will trap large particles of contaminants and trace elements. The method is quite popular for domestic and industrial use. Because the water after membrane purification is completely purified from hardness salts, without losing taste qualities. But a significant advantage of the method in a wide range of temperatures during softening, while the water does not lose its properties. However, quite a lot of water goes down the drain, which makes the method ineffective at high capacity. To increase the volume of softened water, several membranes are installed. Also, if modernization is necessary, the system can always be supplemented with any accessories.

Fig. 4 Wagner-250 reverse osmosis system

2.4 Reagent method

Another way to make water soft is to use chemicals. When reagents interact with calcium and magnesium ions, a chemical reaction takes place and precipitation occurs. For complete purification, it is recommended to install additional filters that will remove the scale. As a rule, loading is used. This method is more suitable for industrial production, as the use of chemicals must be strictly dosed, based on the volume and performance of the system. In addition, there is a possibility of residual reagents in the water, which is unacceptable in domestic use. In addition, proper disposal of water going down the drain is required. Reagents should be used carefully, as they can create additional decomposition products during softening. To avoid such situations, a chemical dispenser and a filter for final cleaning are used, which will trap the remaining harmful elements and the resulting sediment.

Fig. 5 Scheme of pressure reagent deferrization system

3. Comparison of softening methods

Each method has its own pros and cons. To purify water from a well, some nuances should be taken into account. First of all, a chemical analysis of water is taken and on the basis of these data the method is selected. Also important is the place of use of the softening system. Will it be an industrial sphere or a household segment. Also the choice is affected by the frequency of use of the softening system. If you consider a country plot, which is used only in the summer, you can not install a large-scale water softening system. The simplest way is the use of chemicals. They are able to remove not only calcium and magnesium salts, but also other impurities. However, this requires the installation of special dispensers and accurate calculation of the amount of reagents. If these nuances are not observed, the composition of water can change significantly. It is worth considering the cost of reagents and the installation of a finishing filter for complete purification from the remaining elements of the reaction.

Softening system based on reverse osmosis is quite universal and common. Water after membrane purification becomes soft and devoid of any trace elements at all. At the same time, it is necessary to install additional filters for pre-cleaning. Because the membrane removes even the smallest impurities and the presence of large particles will significantly reduce its service life. Additional filtration elements are also installed to bring the water composition to an optimal state. The capacity of the system is small.

The method of ionic softening allows you to quickly remove hardness salts without residue. The principle of substitution copes with the assigned tasks quite quickly. The possibility of regeneration is a huge advantage of this method. However, the salt solution used to wash the filter requires additional cleaning before disposal. Firstly, it is itself too saturated with salt. Secondly, it has a high concentration of calcium and magnesium ions.

And finally, boiling. A relatively quick way to soften water, but is suitable only for small amounts of water. Due to the large expenditure of time and energy. In addition, the remaining scale is difficult to remove.

Having considered the advantages and disadvantages of softening methods, you can make a choice, taking into account some nuances. Water must strictly comply with the regulations. Hard water is not suitable for use. But also too soft is not beneficial. So how to choose the golden mean. To begin with, it is necessary to start from the initial analysis of water. Given this data, the system and method is selected. The need for additional components is calculated. This may be a pumping station, in case of low water pressure. Or dosers when using the reagent method. The need for automation of the system is also taken into account. On the one hand, such a possibility will get rid of the observation of the softening system and will itself calculate the time for washing or regeneration of the filter. On the other hand for household use such a load would be unnecessary. In addition, the performance of the system is also taken into account. The highest in the reagent method, the lowest in reverse osmosis systems. If the ionic softening method is chosen, the utilization of the concentrate after regeneration should be considered.

Table 1. Softening systems

Based on these data, it is possible to choose the method that best meets your needs. It is worth considering that any system can be modernized by installing additional elements and components. It is also worth considering the performance of the system and correlate the consumption of raw water with the received water. If the difference is large, and losses should be minimized, it is better to try another method of softening. In addition, the output water should not only be purified from calcium and manium salts, but also comply with regulations. For domestic softening, the size of the system is important. Compact units will be more acceptable in this case.

Water softening. Calculation of the period between regenerations with salt.