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The steps of water treatment in the treatment plant are slightly different depending on whether the goal is to increase the quality of surface water or underground water. According to the type of polluting substances and their amount, different methods and steps may be implemented, and in each step, an effort is made to improve the determining factors of water quality. Haft Industrial Group; The manufacturer of water purification equipment will refer to the main stages of water purification in the water treatment plant.

water catchment; The first stages of water treatment in the treatment plant

After entering the water treatment plant, surface and underground water are first stored in special reservoirs. These catchments provide conditions for water to be stored in an environment without movement and turbulence, and a large volume of polluting and suspended materials will settle in it. In order to increase the quality and clarity, the water in the reservoir is slightly purified with nets and special garbage collectors at this stage. At this stage of purification, water quality indicators do not face much change, and the only purpose is to store water to enter other parts and stages of purification.

Where do they pass the water in the treatment plant to get the mud?

One of the biggest challenges in the process of water purification is removing the mud in them. There are various methods to remove this mud, the least expensive of which is to pass through the sand bed. The mud is attached to the very fine grains of sand, and in this way clean water passes through it. This method is inspired by the behavior of nature. Of course, in industrial units, this process is mostly done with the help of sand filters, which have the same application as a sand bed.

Physical purification with scavenger

Surface water is polluted with a large amount of particles and pieces of solid materials such as wood, cloth, leaves and tree branches, etc. These solid particles suspended in water have a negative effect on its turbidity. In addition, their entry into other wastewater treatment equipment not only causes the half-life stages to be longer, but also may disrupt various equipment and devices. For this purpose, as the second step of the water purification process in the water treatment plant, an equipment called a garbage collector is used. These equipments have a high variety and in all of them the goal is physical water purification by collecting large solid particles suspended in water. Garbage collectors used in treatment plants have a high variety, among which the following can be mentioned:

• Manual garbage collector
• Mechanical scavenger
• A pair of net scavengers

In all types of garbage collectors used in treatment plants, the purpose is to prevent the entry of solid particles, pieces of wood and leaves, etc. in the water into the canal and different parts of the treatment plant. For this reason, in different parts such as the entrance of purification ponds and other parts, various types of garbage collectors are used with large to small distance between the bars. In addition to the differences in the distance between the bars in the garbage collector plates, the way of collecting the materials accumulated in them is also different. So that in some of them, the collection of these materials is done by human power, and in some of them, this process is done with the help of mechanical power. It should be noted that garbage removal is one of the steps of water treatment in the treatment plant, which not only affects the quality of water, but also increases the lifespan of other treatment equipment.  

preliminary chemical treatment; The third step of the water purification process in the treatment plant

One of the challenges in surface water treatment is the growth of algae and different plants in the treatment ponds. For this reason, in the design of water purification steps in the water treatment plant, attention is paid to this issue and a part is considered as preliminary chemical purification. In this section, with the help of various chemical substances, efforts are made to prevent the growth of algae and other aquatic plants. Among the materials used in this step, we can mention copper sulfate and activated charcoal powder. Of course, it should be noted that in this step, in order to prevent the growth of plants and algae, various operations are used, among which we can mention the harvesting of plants on the bottom of the pool. In addition, different types of crabs and snails can be used to destroy plants on the bottom of the pool, which is also considered as biological treatment. If these two steps are not successful, some herbicides are used, which is a kind of chemical treatment.

Preliminary settlement

After the removal of plants and algae, as well as the preliminary treatment, there are many small suspended particles in the water, which have a negative effect on the darkening of the water. For this reason, these particles should be removed with the help of different methods. Sedimentation is one of the most practical methods that do not require chemicals, etc. This stage of water purification in the water treatment plant provides conditions in which a large volume of solid and fine particles suspended in the water gradually settles. In order to increase the settling speed of these particles, factors such as water temperature can be increased.

Surface water nets

Among other stages of water purification in the treatment plant, we can mention the use of surface water nets. These nets have become cylindrical and circular, and due to the very small holes on them, a large amount of small and suspended substances in the water are removed with its help. In order to increase the quality and efficiency of these nets, it is necessary to wash their surface in different ways to prevent clogging of their tiny holes.

Aeration in water treatment in treatment plant

One of the most important stages of water purification in the water treatment plant is aeration, which causes a very high volume of gases in the water to be removed and improves the taste and smell of the water. In addition, water aeration causes many pollutants to be oxidized with the help of oxygen entering the water, and finally the turbidity of the water will decrease. Among the effects of using aeration in water purification, we can mention the reduction of hydrogen sulfide, iron and manganese, methane and carbon dioxide and improving the taste of water. Aeration in water purification is done in different ways and according to the type of equipment in the treatment plant as well as the amount and type of pollutants, water may be dispersed and sprayed outside in some conditions and air may be sprayed into the water in some conditions. is injected For this purpose, various types of surface aeration, fixed aeration and deep aeration or risk and tube diffusers are used.  

Coagulation and clotting

The next step of the water purification steps in the treatment plants is coagulation and flocculation, which is done with the help of chemicals and polymers. The reason for using these materials is the non-settlement of some particles and ions in the water, which lead to its turbidity. For this reason, various materials such as polyelectrolyte and active silica are used, which entering and mixing in water causes negative particles with positive charges of these materials to be absorbed and form clots. Finally, these coagulated materials float on the surface of the water and are collected with the help of different equipment. In addition to collecting clotted materials, they are also given the opportunity to settle smaller particles on the bottom of the ponds.

getting tough

Considering that one of the biggest challenges in water purification is the presence of a large amount of calcium and magnesium in the water, which ultimately lead to an increase in water hardness, as an important step in the water purification process in the water treatment plant, the hardness The tightening is done by a tightening device. In order to reduce water hardness, several methods are used, the most common of which is the use of ionic resin beads. In addition, lime and calcium carbonate lime are also used in order to slightly reduce the hardness of water. In the use of ion exchange with the help of resin grains, calcium and magnesium ions are tried to replace the sodium ions in the resin. For this reason, it is necessary to regenerate the resin grains used in this step in different ways.

Water disinfection is one of the most important stages of water treatment in the treatment plant

As the final steps for water purification, it is necessary to perform disinfection in different ways. Disinfection of water in treatment plants may be done with chemicals such as chlorine and ozone, or with heat, light, and electromagnetic radiation. In the disinfection stage, it is also necessary to check the pH level of the water so that this factor can be adjusted to a neutral state.

Storage

As the last stage of water purification in the treatment plant, it is stored in large tanks to enter the city water pipes through different channels.