industrial methods of water treatment and filtration

industrial water filtration and purification

Clean water in large quantities can be applied in different cases .For each case water treatment will take place in different ways.

We divide the cases of industrial water purification into three groups:

  • Industrial cleaning of water, when water is the end product. (For example - large-volumes production of bottled water, cleaning water for the central water supply systems and large consumers)
  • Purification of water for industrial production of other products (Food, drinks, perfumes, pharmaceutical industry, etc.).
  • Cleaning and water treatment for use of water as the process fluid (For example as a coolant in the heating and energy systems as reagent in the chemical industry and other industries)

Scheme of water purification and composition of equipment will be determined for each case separately.

For example, do not always need a strainer. In cases where the water has unique requirements, for example - in pharmaceutical industry - water purification scheme can be very complex and expensive. In this case, unacceptable risk of getting any infections through the water. In the chemical industry composition of the water can greatly influence the course of reactions and the consumption of expensive reagents.

Each process step requires a different water quality. Since water purification processes is a complex and expensive undertaking, the treatment is always carried out to the minimum acceptable level for this technological process. Thus, on one industrial facility can simultaneously operate multiple water purification schemes, implementing different methods using different equipment and materials and producing clean water to various degrees of purity. Sometimes they can be considered as the aggregate subsystem total water purification system at the enterprise as a whole.

In each case, the filtration system is installed completely different, corresponding to the nature of impurities. Currently, pure water has become a deficit, so most industrial plants purify the wastewater and re-use them, which is very beneficial for them and besides does not pollute nature and ecological environment.

Industrial water filtration systems come in different types, here are the main ones: common industrial strainers are used for the detention of large insoluble impurities such as rust, sand, clay, slurry. Strainers considered obsolete, but they are simple and practical to use quite easy to clean and can be operated at a low operating pressure. Disc filters are widely used, their degree of filtration is determined by the size of the hole being formed by compression of the disc under the influence of water pressure. They are made of a polymeric material that provides ease of cleaning and high performance.

Special industrial systems for water softening, continuously provide training softened water, which helps protect equipment from scale, sedimentation of magnesium and calcium salts. In this case, the principle of ion exchange, of course, occur and recent developments, for example, a combination of a filter and a method of ion exchange electrodialysis. These softeners are used in the food industry, medicine, municipal water services, power system, and many other enterprises.

Industrial water disinfection system with the installation of UV lamps allow to destroy harmful bacteria, making the water completely safe to use. Its main advantage is that the water is not exposed to chemical attack, it does not change their taste and organoleptic properties. Disinfection of water and industrial waste water on a large scale in a few seconds. Water filtration using activated carbon removes odors, taste, organochlorines. Industrial water filtration system filters used in coal activated carbon to remove organic molecules having a large size.

By the type of water flow motion diagrams of treatment are divided into gravity-fed (free-flow) and pressure. In the municipal tap-water and major industrial waterworks movement of raw water from the construction to the construction is carried out by gravity. At the same time mark the water table in each subsequent construction below the previous year. Height difference determines the pressure required to overcome the hydraulic resistance inside the building and in communication from one to the other facilities.

Technological scheme of industrial water purification and water treatment includes the following main stages:

  • Mechanical cleaning of water from suspended particles
  • Removal of iron and manganese from water
  • Removal of organic contaminants (bleaching, deodorization)
  • Water softening
  • Desalting
  • Removal of microbiological contamination
  • Correction of the composition of water (alkalinity, acidity, content of individual elements)

Used technological solutions depend on the quality of source water, needs of treated water, purity and consumption mode.

The first step in treatment is the mechanical treatment of water to remove suspended insoluble impurities, which is realized on the granular media, sump, filters, disc filters or by settling with additional precipitants to accelerate and improve the efficiency of the cleaning process. In some cases mechanical treatment is combined with the removal of iron as a catalyst filling folder remove iron has good filtration efficiency (up to 20 micrometers) or sorption lightening, when used as a grain loading in the filter is not inert filter loading and the sorbent which has filter and sorption properties. Finer filtration is carried out using membrane filtration techniques.

Removal of iron from the water occurs during the oxidation of ferrous to ferric iron (on catalyst loading, making the process efficient and rapid oxidation). As the oxidizing agent used oxygen, permanganate, sodium hypochlorite. Iron precipitates in the form of flakes of red color, detained on the filter medium and gravel layer.

Cleaning water with injected air or other oxidant (permanganate, hypochlorite) is fed to the control unit (head) and out of the top of the filter, is introduced inside through a distribution system, filtered downward through the loading layer is cleaned with from iron and suspended through particles and disposed below the drainage filter placed in the gravel layer, a filter and flow out from there to control unit.

The air parts insoluble in water, which collects in the top of the filter and output there from through an air circuit (purge valve).Other oxidizing agents catches with adsorbent filters (activated carbon).

When filter has a pollution , pressure drop is increases and decreases productivity. At the time of commissioning in the frequency and time (usually at night), the control unit is installed in the filter that automatically switches to download recovery mode. Regeneration is carried out by spraying water at high velocity from the bottom up and discharge of waste water into the sewer. The rate is set above the fluidization speed of loading one in which it is expanding by 30-50%, which allows you to completely remove it with the dirt detainees fluids.

Then, water softening - the removal of salt from her rigidity on special ion exchange resins.

Depending on the purpose of purified water and the need for it, as well as the quality of raw water (the need for pre-treatment), all purification steps after the mechanical treatment can be implemented by membrane purification techniques in a single hardware solution. After removing the mechanical undissolved impurities by mechanical cleaning, also known as pre-filtration or pre-treatment, it is a correction of the ion composition of the water, ie, separate removal therefrom of dissolved iron ions (iron removal) of calcium and magnesium (softening), etc., and organic molecules pyrogenic contamination -. Bacteria and viruses are also removed by membrane techniques in parallel with the adjustment of ionic composition of water). We are talking about the use of reverse osmosis or nanofiltration for the preparation of highly purified water. In this reverse osmosis membrane selectivity is significantly higher than in the case of singly charged ions by nanofiltration.

Membrane methods are highly efficient equipment has smaller dimensions compared to the ion exchange purification techniques, requires virtually no reactants, but less efficient compared with the same ion exchange methods, the equipment has a high cost for the same performance. Reverse osmosis and nanofiltration is advisable to apply in cases of need for highly purified water at a relatively low demand for it (the perfume, food and pharmaceutical industries).

Where it is critical of the removal of water impurities, or only some require a high-performance water treatment, it is advisable to use a combination of ion-exchange techniques.

In general, industrial water treatment involves the following set of cleaning:

  • industrial mechanical water purification filter (hot and cold water)
  • industrial filters water softener (industrial water softeners and magnetic transducers)
  • industrial complex filters, iron removal of water
  • industrial complex filters dechlorination of water (water adsorption system or carbon filters)
  • industrial complex filters for water disinfection (disinfection of water systems, water stations silvering UV water disinfection)
  • production of water filters aeration (aeration columns, injectors, compressors, injectors )
  • industrial complex filters for water purification for drinking water (reverse osmosis or nanofiltration)
  • industrial complex fine water filters (industrial microfiltration)
  • production of circulating water filter (water treatment revolving cycle)

For proper operation of the entire purification system requires a centralized system of the whole complex. Proper functioning of all components of water consumption depends on the initial project, which should be developed during the construction or design of the industrial complex.