The basic knowledge of environmental protection water treatment is all here!

In addition to the salt content or conductivity of pure water and ultra-pure water have strict requirements, the content of various metal ions in water, the content of organic matter, the size and number of particles and the number of microorganisms also have strict indicators

40, distilled water: the raw water is heated and vaporized, and then the water condensed into steam is called distilled water. Generally, the conductivity of distilled water is about 10μs/cm, and the distilled water is distilled again to obtain secondary distilled water, and the distilled water is distilled multiple times, and the conductivity can be reduced to a very low of about 1.0μs/cm.

41, scale inhibitor: It is a kind of agent that can disperse insoluble inorganic salts in water, prevent or interfere with the precipitation and scaling of insoluble inorganic salts on the metal surface, and maintain the good heat transfer effect of metal equipment.

42, ion exchange resin: It is a polymer compound with a functional group (an active group of exchange ions), with a network structure and insolubility. Usually spherical particles.

43, ion: refers to the atom due to its own or external action to lose or get one or several electrons so that it reaches the outermost electron number of 8 or 2 (helium atom) or no electron (four neutrons) stable structure. This process is called ionization.

44, water production (water flux) : refers to the capacity of the reverse osmosis system, that is, the amount of water per unit time through the membrane, usually expressed in tons/hour (t/h) or gallons/day (g/d).

45, EDI: referred to as continuous electric desalting, is a new ultra-pure water preparation technology. It cleverly combines electrodialysis technology and ion exchange technology.

Second, pure water treatment basic process explanation

1, coarse filtration: refers to mechanical filtration, removal of suspended matter in water, colloids, turbidity, color, odor and so on. The main filtration methods are clarification tank, fast filter, sand filter, sand filter, multi-media filter, active carbon filter, disc filter, high efficiency fiber filter and so on.

2, fine filtration: the filter membrane made of special materials, high filtration accuracy. Common for microfiltration membrane and filter element filtration.

3, ultrafiltration: is a membrane filtration, remove macromolecules and colloids, bacteria and so on. High filtration accuracy, the common is ultrafiltration membrane.

4, reverse osmosis: reverse osmosis referred to as RO, the principle is that raw water under the action of high pressure through the reverse osmosis membrane, the solvent in the water from high concentration to low concentration diffusion so as to achieve the purpose of separation, purification, concentration, because it is the opposite direction of natural penetration.

5, ion exchange: all kinds of inorganic salts in the water ionization to produce positive, anion, through the hydrogen ion exchanger layer, the cation in the water is replaced by hydrogen ions, that is, the salt removal principle of the Yang bed; When passing through the OH-type ion exchanger layer, the anions in the water are replaced by OH- ions, that is, the principle of salt removal in the negative bed.

The mixed bed is an ion exchange device in which positive and anion exchange resins are mixed and filled in the same exchange column in a certain proportion.

6, EDI: is the combination of electrodialysis and ion exchange of the new process of salt removal, take electrodialysis and mixed bed ion exchange, the use of ion exchange for deep treatment, without chemical regeneration, ionization to produce H+ and OH-, to achieve the purpose of regeneration resin.

Third, commonly used water treatment technology

1, the raw water is groundwater: sand filter + precision filter + reverse osmosis + mixed bed or EDI

2, the raw water is tap water: sand filter + activated carbon filter + precision filter +RO+ mixed bed or EDI

3. Surface water:

① Multi-media filter + active carbon filter + precision filter +RO+ mixed bed or EDI

② Multi-media filter (or other forms of filter)+ ultrafiltration + precision filter +RO+ mixed bed or EDI

③ Disk filter + ultrafiltration + precision filter +RO+ mixed bed or EDI

4. Pipe materials commonly used in water treatment projects

1, carbon steel pipe: used for raw water inlet pipe

2, UPVC pipe: for pipe diameter less than DN150 occasions is better, easy to install.

3, stainless steel pipe: for occasions with special requirements, mostly used in small pharmaceutical systems.

4, steel lined rubber or plastic pipe: used in large projects, reliable use, construction is more troublesome.

5. Various uses of pure water

Pure water and ultra-pure water are widely used in power plants, electronics, medicine, chemical industry, through various membrane filtration or ion exchange, the harmful ions in water are removed.

1, power plant: multi-purpose desalted water, the main indicators of the desalted water quality are: hardness is about zero, conductivity ≤0.2μs.cm, SiO2≤20ppb.

2, chemical plants: chemical water is diverse, usually the water quality is not higher than the water quality of the power plant, but it may have requirements for some ions, so it is commonly used a primary or secondary reverse osmosis process. The effluent water conductance is above 5~10μs.cm. Mixed bed or EDI is added to the back if there are higher requirements.