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Ultrapure Water FAQ - What is what? - Glossary Water Treatment compact

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Treated water is essential in laboratories and medicine. But why is water treatment more important than ever today ?

Water is the most versatile element of all. It is used as process water, rinsing water for bath maintenance or as boiler feed water. In hospitals and laboratories, pure and ultrapure water is required for general and specific applications. Central sterile supply departments use treated water to supply autoclaves, sterilizers and laboratory dishwashers.

What special processes are suitable for water treatment results, for example, from the water analysis, the water requirement and the respective requirements for the product water. Filtration, ion exchange, reverse osmosis, ultrafiltration, microfiltration or the electrodeionisation (short: EDI ) are just a few examples of the water treatment process.

- Activated Carbon Filter -

Activated carbon filter serve to adsorb organic compounds and to remove chlorine and chloramines. Activated charcoal is based on charcoal, wood or coconut shells and is therefore a natural product.

- ASTM Type I, and III -

The American Society for Testing and Materials defines different standards for the quality of pure and ultrapure water with types I - III. The ASTM types specify certain properties of the water, such as spec. electrical resistance, spec. electr. conductivity, total organic carbon (TOC value), sodium, chloride and total silicate content, the germ count (CFU) and the limit value for endotoxins (EU/ml).

- Bag Filter -

Bag filters are used for final filtration with very low concentrations of solids and are characterized in particular by the wide range and easy handling when changing the filter bags. Alternatively, they can also be used to separate coarse particles. The water to be treated enters the top side of the bag filter housing and then runs through the filter bag. In this way, the solids are held back in the filter bag. If the bag filters are exhausted, they are emptied and used again after cleaning.

- Boiler Feed Water -

In many branches of industry, water and steam are used in production for heating, as process steam or for generating electricity. The boiler feed water is the elementary drive medium of systems for heat and steam generation, such as in steam power plants. Minor dirt or impurities in the water can disrupt the operation of the very complex systems and, in the worst case, lead to damage. Modern and economically working boiler systems therefore require the treatment of consistently high-quality boiler feed water.

- Candle Filter -

Candle filters are non-backwashable protective filters that filter impurities from the water, such as small solid particles, rust particles and grains of sand. The contaminants are retained on the surface of the wound or thermally bonded fibers. The candle filter consists of a filter housing and one or more differently constructed candles inserted in it. In addition to the wound cartridge (depth filter), filter cartridges designed as membrane filters (surface filters) are also available. Depending on the raw water quality, candle filters should be replaced regularly.

- Carbonic Acid -

A distinction is made between free and chemically bound carbonic acid. In the case of the latter, it is important to note whether it is carbonate or bicarbonate carbonic acid. Each value of bound carbonic acid has a certain value of free, so-called associated carbonic acid (equilibrium carbonic acid). The quantity exceeding the equilibrium carbonic acid is called aggressive carbonic acid, more precisely calcic aggressive carbonic acid. The total amount of free carbonic acid is equally aggressive towards metals.

The determination is made by titrating 100 ml water with 1/10 normal hydrochloric acid and with 1/10 normal sodium hydroxide solution. Methyl orange and phenolphthalein are used as indicators.

- Cooling Water Treatment -

In cooling circuits, large amounts of water are required in the circuit and for evaporation. In order to avoid corrosion and deposits and to comply with the water-chemical and microbiological requirements, the cooling water treatment and water conditioning must be tailored to the requirements in compliance with VDI 2047-2, 6022 and 3803.

- Deferrisation Filter -

Deferrisation filters remove the iron and manganese from the water using catalytic filter material and quartz gravel. The dissolved iron and manganese are oxidized and then filtered off. For water with coarse dirt particles, an appropriate filter should be installed.

- Decarbonization -

Decarbonization (also decarbonization) removes the carbonate hardness, which is caused by the hydrogen carbonates of calcium and magnesium dissolved in the water. Decarbonization plants have weakly acidic H-form ion exchange resins. Cations, calcium and magnesium are bound to the exchange mass and the hydrogen carbonate anion is converted into carbonic acid. The carbon dioxide produced when the carbonic acid decomposes is expelled from the water with air using a trickle deaerator and the exhausted exchanger mass is regenerated with hydrochloric acid.

- Deionized Water -

The term deionized water stands for fully desalinated water. The terms deionized water, deionized water, demineralized water or demineralized water are also frequently used. Deionized water is made ion exchanger Obtained from drinking water by retaining the minerals present (salts and ions). Tap water is used for smaller quantities, and surface or well water for larger quantities. A parameter for measuring the quality of deionized water is the electrical conductivity, which is given in micro-Siemens per cm (µS/cm). The requirements for deionized water quality vary from industry to industry. In many industrial applications, for example as a heat carrier in the coolant circuit of a power plant, for metal cleaning systems, air humidifiers, rinsing baths and galvanic baths or for the supply of steam boilers and steam turbines. In addition, deionized water is used in hospitals, laboratories and in medical technology.

- Desalination/Waterdesalination -

Desalinated water is used in many industrial and commercial processes in hospitals, laboratories and in medical technology, since the salts contained in the raw water can have serious consequences. Water desalination is therefore of fundamental importance in these areas. The classic process technologies used in desalination include Ion exchange, Electrodeionization (EDI) and Reverse osmosis.

- DIN EN 285 -

The DIN EN 285 standard describes the verification of the safety and performance of a steam sterilizer and its process within the meaning of the 93/42/EEC directive on medical products. Since there is no standard for fully desalinated water for mechanical treatment, a boiler feed water quality defined in DIN EN 285, Appendix B is also recommended for cleaning and disinfection devices for the treatment of medical products.

- DIN EN 15883 -

This European standard applies to washer-disinfectors and recommends the use of water treatment, as appropriate, using softening, ionization or reverse osmosis systems.

- Dosing Technology -

The dosing technology, also called dosing station or dosing system, performs particularly precise dosing. An example is the conditioning of boiler water or cooling water to prevent corrosion and deposits. The dosing pumps are selected individually for each water treatment system.

- Electric Conductivity -

Electrical conductivity, given in μS/cm (Microsiemens per cm ) or S/cm (Siemens per cm ), is the reciprocal value of the measured electrical resistance in Megaohm/cm. The electrical conductivity is useful for assessing the salinity of the water.

- Electrodeionization -

The Electrodeionization (EDI) ion exchange resins and ion selective membranes are combined with direct electric current to remove ions from water. By applying an electrical voltage, the water inside the cell is split into H+ and OH-. The cations H+ or Na+ can migrate through the so-called cation permeable membrane, just like the anions through the anion permeable membrane. The ions migrate in the direction of the applied voltage, i.e. the anions to the positive pole (anode), cations to the negative pole (cathode). The water ions H+ and OH-, which migrate through an ion exchange chamber, then displace the salt ions that are on the ion exchange resins and continuously regenerate them. The salt ions migrate through the corresponding ion-selective membranes into the concentrate chambers and are flushed out there with water. Since all concentrate chambers are flushed through one after the other, excess H+ and OH- can combine again to form H2O.

- Full Desalination -

Complete water desalination means the complete removal of all salts from the water to be treated. Other water components are not removed. Therefore, the usual procedure for this complete desalination is the use of a strongly acidic cation exchanger and a strongly basic Anion Exchangers.

- Gravel Filter -

Gravel filters are used to remove undissolved solids from the water and are used, for example, for the pre-filtration of well water, surface water or for the filtration of cooling water. The gravel filter consists of a container with a gravel bed as filter material through which the water is pressed. The dirt particles are held back in the filter material.

- Ion Exchanger -

There are salts in different concentrations in drinking water. These consist of cations and anions. Special ion exchange resins are used to remove these. So a Cation Exchanger selectively cations (sodium ions, calcium ions, potassium ions) and gives off hydrogen ions to the water. A Anion Exchanger in turn selectively binds anions (sulphate ions, chloride ions) and in return releases hydroxide ions into the water. The result is fully desalinated water.

- m-Value -

The m-value is a measure of the carbonate hardness (HC03-+). A positive m value means that the water is acidic and its pH is greater than 4.3. It is determined by titration of 100 ml water with 1/10 normal hydrochloric acid to pH 4.3. Methyl orange is used as an indicator.

- Multy-Layer Filter -

Multi-layer filters retain even the finest dirt particles in the water through depth filtration and adsorption. They consist of two or more filter layers with different grain sizes, such as quartz sand and anthracite coal.

- Metal Cleaning -

The treated water is of elementary importance for metal cleaning, as drilling, milling, turning or welding work is carried out in metalworking companies. With desalinated water, the systems can be better cooled and lubricated, tools and cutting emulsions can be used longer and bacterial growth and corrosion can be minimized.

- Microfiltration -

Microfiltration retains all ingredients in the water that are larger than the membrane pores. The pores are in the range of about 0.05 to 10 µm. A characteristic of this method is the tangential overflow (cross-flow filtration) of the membrane, in which the water is not pressed directly through the membrane, but flows across the membrane. This achieves a cleaning effect on the membrane and increases the service life of the system many times over.

- Nanofiltration -

Nanofiltration reduces turbidity and coloration in surface water. It is also used for partial softening. With this membrane technology, mainly divalent ions and larger molecules are retained. This system is therefore similar in structure and function to the Reverse osmosis.

- Organic Substances -

The consumption of potassium permanganate can be determined by oxidizing the organics with potassium permanganate (KMnO4). It is a somewhat specific cumulative parameter for the water's organic matter content.

- Oxygen -

Oxygen is determined colorimetrically or with electronic measuring devices and given in mg/l. Normal tap water contains between 5 to 10 mg/I oxygen. Thermally degassed Water should contain less than 0.02 mg/l oxygen.

- p-Value -

The p-value is a measure of free alkalinity (C03--+0H-). A positive p-value means that the water is alkaline and the pH value is greater than 8.3. It is determined by titrating on of 100 ml of water with 1/10 normal hydrochloric acid 8.3. Phenolphthalein is used as an indicator.

- Partial Desalination -

Partial desalination for water treatment represents a special case. If the water has certain ingredients (e.g. only carbonate hardness), a sufficient desalination effect can be achieved by using a weakly acidic cation exchanger. Other water components are not removed. Therefore, the usual procedure for this complete desalination is the use of a strongly acidic Cation Exchanger and a strongly basic Anion Exchangers.

- pH-Value -

PH is a measure of hydrogen ion concentration. Measuring range 0-14. In practical use, the measuring range is mostly 2-12. Neutral water has a pH of 7.0. If the pH is less than 7.0, the water is acidic. If the pH value is greater than 7.0, the water is alkaline. The measurement is carried out electronically or with pH indicator papers. In low-salt water, some neutral salt must be added before the measurement.

- Process Water Treatment -

Industrial water, also known as process water or service water, is often used in industry for cooling, production or as rinsing water. Rainwater, well water, river water or brackish water, among other things, is used for the treatment of process water. Depending on the application, different process technologies of the Water treatment such as Filtration, ion exchange and membrane techniques are used.

- Process Water -

Industrial processes often require specially treated water or steam. This includes water that is used for product manufacture, for cleaning purposes and as an auxiliary medium for heating or cooling processes. Raw water from drinking or well water is used for the production of process water. Alternatively, surface water and bank filtrate can also be used. Through precisely coordinated process technologies such as Filtration, Softening, Ion exchange, membrane processes, etc., the process water is optimally prepared for the area of ​​application. The criteria and requirements are different. The particle content, the hardness, the salt content but also organic and microbiological contamination are often decisive factors for the investment in a Hartmann GmbH water treatment system. The water is fed back into the process thanks to the resource-saving circulation technology, since the treated process water is too valuable to be used once.

- Protective Filter -

Protective filters protect pipeline networks and downstream systems from coarse and fine-grained contamination. Without these filters, deposits can form on the metal pipes, which can lead to pitting damage due to contact corrosion. On the other hand, deposits in plastic pipelines often cause constrictions, which can lead to a corresponding loss of pressure.

- Reverse Osmosis -

The Reverse Osmosis , also known as reverse osmosis (RO) is the simplest type of water treatment, in which the natural law of osmosis is simply reversed. A reverse osmosis system works by filtering harmful substances such as bacteria, viruses, germs and other contaminants out of the water using a semi-permeable membrane.

In addition to particulate matter in the water, ions are also held back. As an example, cherries that have burst after a summer rain should serve here. The cherry juice is a concentrated solution, the raindrop is a diluted solution, and the concentrations are balanced through the skin of the cherry. The solvent - i.e. the raindrop - enters through the cherry skin and the system tries to balance the two concentrations. The problem with this is that the volume of the cherry cannot increase, so the osmotic pressure rises. In nature, this increase causes the cherry to eventually burst.

If this effect is reversed, you get a Reverse osmosis. In doing so, so much pressure is exerted on the concentrated solution that the osmotic pressure of this solution is overcome. The solvent passes through the membrane again and all dissolved water components remain on the concentrate side.

How osmosis and reverse osmosis work is also explained in the video. You can also find a more detailed description of reverse osmosis in the chapter Pure water treatment.
Animation functional principle of Reverse Osmosis

- Rinse Water Treatment -

The rinsing water treatment with recirculation uses large amounts of water at a higher temperature in order to optimize the rinsing result while reducing costs at the same time. The final rinse with deionized water also ensures consistently high quality assurance for the products to be cleaned. Whether you work in an open or closed circuit depends in particular on the washing process and the items to be cleaned. Open systems are advantageous when the recycling effort is too high and indirect discharge is possible.

- Ultrafiltration -

In ultrafiltration, water is filtered through a polymeric membrane with a very fine pore structure. In particular, the process is used for difficult raw water with a seasonally fluctuating particle load. In this way, ultrafiltration with its defined cut-off point and its individual backflushing concepts can demonstrate its advantages. Thanks to the modular process technology, you can react flexibly to changes in the required quantities and to fluctuations in the raw water composition. Another advantage is the higher performance in terms of particle retention.

- UV-Sterilization -

One way of sterilizing the water in the post-treatment is the UV disinfection. The microorganisms in the water (bacteria, viruses, other microorganisms) are irradiated with high-energy UV light, which damages their DNA. The organisms can therefore no longer reproduce and the water becomes germ-free. The advantage of UV radiation is that no chemical substances are added to the water. The use of harmful and possibly carcinogenic chemicals is therefore no longer necessary. In addition, the UV sterilization with lower operating costs than chemical disinfection, since only electricity costs and the costs for changing the lamp are incurred.

- Water Treatment System -

The water treatment systems from Hartmann GmbH are characterized by their modular design. All cleaning stages can be delivered in an open frame or a closed housing on request. The water treatment systems are optimally adapted to the spatial conditions and can be installed and commissioned on site within a very short time.

- Water Softening -

With the water softening cations (calcium ions and magnesium ions) responsible for water hardness are exchanged for sodium ions. This is done with the help of cation exchange resins. The strongly acidic cation exchanger is loaded with sodium ions and exchanges them for calcium and magnesium ions. The process of water softening can also be reversed for regeneration. A saturated saline solution is used for this, which is produced, for example, by dissolving saline tablets.

- Water Hardness -

The hardness of the water is given in French (°fH) resp. German degrees of hardness (°dH) or in Val (val/m³) resp. millival (mval/l) or millimole (mmol/l). A distinction is made between carbonate hardness and non-carbonate hardness. The sum of these two hardships gives the total hardness. The total hardness is usually determined trimetrically using the complexon method.

1°f hardness resp. 0.56 °d hardness corresponds to 10 mg/I calcium carbonate.
5°f hardness resp. 2.8 °d hardness corresponds to 1 mval/I or 0.5 mmol/I.

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