Explanation of Water Treatment Terms

Explanation of Terms:
1. Raw water: refers to untreated natural water or urban tap water, also known as raw water

2. Clarified water: Water that removes suspended impurities from the raw water.

3. Demineralized water refers to the water in which the cations and anions are basically removed or reduced to a certain extent, which is called desalinated water. The methods of desalination include distillation, electrodialysis, reverse osmosis, ion exchange, etc.

4. Turbidity: refers to the degree of turbidity in water, which is the optical effect caused by the presence of certain suspended solids (including colloidal substances) in the water. The unit is represented by NTU. Turbidity is one of the main characteristics that visually determine whether water has been contaminated. The standard unit of turbidity is specified as 1 degree, which is composed of 1mgSiO2.

5. Flocculant: An agent that can cause coagulation and bridging of rubber particles, resulting in flocculation.

6. Total alkalinity: refers to the total amount of substances in water that can neutralize strong acids.

7. Acidity: refers to the total amount of substances in water that can neutralize strong alkalis.

8. Hardness: Refers to certain metal ions in water that are prone to forming precipitates, usually referring to the content of calcium and magnesium ions.

9. Conductivity: refers to the conductivity of a solution between two parallel electrodes with a cross-sectional area of 1 square centimeter and a distance of 1 centimeter at a certain temperature. It can indirectly represent the content of dissolved salts in water.

10. Resistivity: It is also an indicator reflecting the conductivity of water. The higher the resistivity of water, the poorer its conductivity, and the less ions it contains. Its common unit is M Ω. CM. It has a reciprocal relationship with conductivity. For example, the conductivity of water is 0.2 μ S/cm, then its resistivity is 1/0.2=5 (M Ω. CM).

11. TDS (Total Dissolved Solids) TDS (Total Dissolved Solids): refers to the remaining inorganic matter after filtering out suspended solids (SS) and colloids and evaporating all water. The unit is ppm or mg/l, which can be measured using a TDS instrument. It also reflects the ion content in the water. There is a rough correspondence between it and conductivity: for a sodium chloride reference solution, a TDS value of 1ppm corresponds to 2 μ Conductivity of s/cm.

12. PH value: The relative content of acid and alkali in the solution. The pH value is a unit of measurement of the negative logarithm (log) of hydrogen ion concentration in water. The pH value is divided into 0-14 levels, and a pH value of 7.0 indicates that water is neutral; If the pH value is less than 7.0, water is acidic; The pH value is greater than 7.0. Then water is alkaline.

13. Alkalinity: Alkalinity refers to the content of substances in water that can undergo a neutralization reaction between [H+] ions and strong acids. The substances that produce alkalinity in water are mainly composed of carbonate alkalinity and bicarbonate alkalinity, as well as hydroxide alkalinity produced by the presence of hydroxides.

14. SDISDI: Pollution Index - used to measure the amount of suspended solids in raw water used in reverse osmosis systems.

15. Ozone: An unstable and highly active form of oxygen that is generated by natural lightning or high-voltage charges passing through the air. It is an excellent oxidant and disinfectant.

16. Residual chlorine: The effective chlorine remaining in water after being disinfected with chlorine and exposed to it for a certain period of time.

17. Total number of Escherichia coli: The total coliform group refers to a group of aerobic and facultative anaerobic Gram negative non-spore bacteria that can ferment lactose at 37 ℃ and produce acid and gas within 24 hours. The total coliform group refers to the total number of coliforms contained in each liter of water sample.

18. Recovery rate: refers to the ratio of the flow rate of product water produced by the system to the inflow flow rate.

19. Desalination rate: Desalination rate: A parameter that reflects the performance of the membrane. Typically, the desalination rate of the primary RO membrane system is above 97%. It can be simply calculated as follows: (conductivity of raw water - conductivity of product water)/conductivity of raw water.

20. Salt content: The salt content of water, also known as salinity, represents the amount of salt contained in the water. Due to the fact that various salts in water generally exist in the form of ions, the salt content can also be expressed as the sum of the amounts of various cations and anions in the water.

21. Sedimentation and sedimentation: One of the technical methods for wastewater treatment. It can be divided into two types of actions: physical precipitation and chemical precipitation. The commonly referred to precipitation is physical precipitation, which is a method of gravity separation. It utilizes the difference in specific gravity between suspended solids in wastewater and water, and separates them from water through gravitational sedimentation or upward flotation. Chemical precipitation is the addition of a certain chemical agent to wastewater, causing it to undergo chemical reactions with dissolved substances in the wastewater, generating insoluble compounds and precipitation.

22. There are multiple interpretations of the definition of "reclaimed water", which is referred to as "recycled water" in sewage engineering and "reused water" in factories. Generally, water quality is used as a distinguishing indicator. It mainly refers to non drinking water that can be reused within a certain range after being treated with urban or domestic sewage and reaching a certain water quality standard. The quality of recycled water is between the upper water (drinking water) and the lower water (domestic sewage), which is also the reason for the name of reclaimed water. People also refer to the system that supplies reclaimed water as the reclaimed water system.

23. Organic pollution
Organic pollution refers to natural organic substances and other biodegradable synthetic organic substances that exist in the form of carbohydrates, proteins, amino acids, and fats. Mainly sourced from domestic sewage and industrial wastewater.

24. Concentration polarization: Under operating conditions of reverse osmosis, the surface salts of the membrane are concentrated, and there is a concentration difference between the salts in the same inlet water. If the flow rate of the concentrated water is low and the flow rate is low, the high content salt water cannot be taken away in a timely manner, and a high concentration difference will form on the membrane surface, hindering the diffusion of salt. This phenomenon is called concentration polarization.

25. Suspended solids (SS): refers to solid substances suspended in water, including inorganic substances, organic substances, mud and sand, clay, microorganisms, etc. that are insoluble in water. The content of suspended solids in water is one of the indicators to measure the degree of water pollution. It is the amount of solid obtained by drying the residue on the filter paper after filtering the water sample at a temperature of 103-105 degrees Celsius. Unit: mg/l.

26. Aeration: The process of transferring O2 from the air to the mixed liquid and utilizing it by microorganisms. The purpose is to provide dissolved oxygen required by microorganisms such as activated sludge and ensure the oxygen demand during microbial metabolism.

27. Biochemical Oxygen Demand (BOD): Biochemical Oxygen Demand (BOD) refers to the dissolved oxygen consumed by microorganisms in the process of decomposing and oxidizing organic matter in water at a specified time, temperature, and conditions. It usually takes 5 days at a temperature of 20 ℃, abbreviated as BOD5, with a unit of mg/L.

28. Chemical Oxygen Demand (COD): refers to the amount of oxygen consumed by oxidizing organic substances in wastewater with strong oxidants under certain conditions. The wastewater inspection standard generally uses potassium dichromate as an oxidant, with a unit of mg/L.

29. Water hammer, also known as water hammer. During the transportation of water (or other liquids), sudden changes in flow rate and significant fluctuations in pressure occur due to sudden opening or closing of valves, sudden stop of water pumps, sudden opening or closing of guide vanes, and other reasons.

30. Adsorption: refers to the method of using porous solids to adsorb certain or several pollutants in wastewater to recover or remove certain pollutants, thereby purifying the wastewater.

31. Enzyme: It is a catalyst (biocatalyst) made by oneself in biological cells. Its basic component is protein, which is a substance that promotes the speed of biochemical reactions.

32. Sewage: Sewage refers to the general term for water discharged in production and living activities. In human life and production activities, a large amount of water is used, which is often polluted to varying degrees. The polluted water is called sewage.

33. Sewage treatment: Sewage treatment refers to the use of various technologies and means to separate, remove, recycle, or convert the pollutants contained in sewage into harmless substances, so as to purify the water.

34. Sewage reuse: The reuse of sewage or wastewater for production systems or domestic miscellaneous purposes after secondary treatment and advanced treatment is called sewage reuse. When the treated effluent meets specific reuse requirements and is reused, it can also be referred to as regenerated water.

35. Scale and scale: refers to the solid attachment formed on the pipe wall in contact with water on the heating surface after a period of operation due to poor water quality of the boiler water.

36. Water slag
Water slag: refers to solid substances in a suspended state in the furnace water and sediment deposited at slow water flow points such as the bottom of the steam drum and lower header. Difference from scale: Water slag is relatively loose, in a suspended or sediment state, and a portion is easily discharged with the boiler discharge; And scale can firmly adhere to the pipe wall and is not easy to remove.

37. Trace amounts of iron and manganese in iron, manganese, and aluminum can cause problems such as staining, scaling, and taste. Iron exists in the form of water-soluble divalent iron in a reducing state. When in contact with air, it gradually oxidizes into yellow brown colloidal trivalent iron, which eventually precipitates into brown iron hydroxide. The characteristics of manganese are similar to that of iron. As the oxides of iron, manganese, and aluminum are also one of the reasons for RO membrane fouling, it is necessary to analyze their content.

38. Pure water refers to water that not only removes strong electrical media that are easy to remove from water, but also removes weak electrolytes such as silicic acid and carbon dioxide that are difficult to remove from water to a certain extent. The salt content of pure water is below 1.0mg/L, and the conductivity is less than 3 μ S/cm.

39. Ultra pure water
Ultra pure water, also known as high-purity water, refers to the removal of almost all conductive media from water, as well as the removal of non dissociative colloidal substances, gases, and organic substances to a very low level of water,. The salt content of ultrapure water is below 0.1mg/L, and the conductivity is less than 0 one μ S/cm.
Pure water and ultrapure water not only have strict requirements for salt content or conductivity, but also have strict indicator restrictions on the content of various metal ions, organic matter content, particle size and quantity, and microbial quantity in the water

40. Distilled water: Distilled water refers to the water formed by heating and vaporizing the raw water, and then condensing the steam. The conductivity of distilled water is generally 10 μ About s/cm, the first distilled water is distilled again to obtain the second distilled water, and the second distilled water is distilled multiple times. The conductivity can be reduced to as low as 1.0 μ Around s/cm.

41. Scale inhibitor: A type of agent that can disperse insoluble inorganic salts in water, prevent or interfere with the precipitation and scaling of insoluble inorganic salts on metal surfaces, and maintain good heat transfer performance of metal equipment.

42. Ion exchange resin Ion exchange resin is a polymer compound with functional groups (active groups that exchange ions), a network structure, and insolubility. Usually spherical particles.

43. Ionic ions refer to stable structures where an atom loses or gains one or more electrons due to its own or external actions, resulting in the outermost electron count of 8 or 2 (helium atoms) or the absence of electrons (four neutrons). This process is called ionization. The energy required or released during the ionization process is called ionization energy. In chemical reactions, metal element atoms lose their outermost electrons, while non-metallic atoms gain electrons, thus causing the participating atoms or atomic groups to charge. Charged atoms are called ions, positively charged atoms are called cations, and negatively charged atoms are called anions. Anions and cations form uncharged compounds due to electrostatic interactions. Like molecules and atoms, ions are also the fundamental particles that make up matter. Sodium chloride is composed of chloride ions and sodium ions.

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

45. EDIEDI (Electrodeionization), abbreviated as continuous electrodeionization, is a new type of ultra-pure water preparation technology that gradually developed in the 1990s. It cleverly integrates electrodialysis technology and ion exchange technology, and achieves ion directed migration to the concentrated water chamber under the action of a direct current electric field by selectively permeating anions and cations through the anion exchange membrane and the ion exchange resin, Thus, the deep desalination of water is achieved to obtain ultrapure water, and the water molecules are electrolyzed into hydrogen ions and hydroxide ions to regenerate the resin, eliminating the traditional acid-base chemical regeneration