Common professional names of water treatment (1-45)

Common names of chemical water treatment:

(1) Surface water. It refers to the water existing on the surface of the earth’s crust and exposed to the air. It is the general name of rivers, glaciers, lakes and marshes. It is also called “land water”.

(2) Groundwater. It refers to the water existing in the cracks in the earth’s crust or in the soil voids.

(3) Raw water. It refers to the water in the nature, including but not limited to groundwater, reservoir water and other natural water sources, without any artificial purification treatment.

(4) pH. It refers to the acid-base value of the solution.

(5) Total alkalinity. It refers to the total amount of substances in water that can neutralize with strong acid.

(6) Phenolphthalein alkalinity. It refers to the alkalinity measured with phenolphthalein as indicator (pH of titration end point = 8.2 -8.4).

(7) Alkalinity of methyl orange. It refers to the alkalinity measured with methyl orange as indicator (pH of titration end point =3.1-4.4).

(8) Total acidity. It refers to the total amount of substances in water that can neutralize with strong alkali, including inorganic acid, organic acid, strong acid and weak alkali salt, etc.

(9) Total hardness. In general natural water, its ion content mainly is Ca2+ and Mg2+, other ion content is very small. Generally, the total content of Ca2+ and Mg2+ in water is called the total hardness of water.

(10) Temporary hardness. The hardness formed by the presence of Ca(HCO3)2 and Mg(HCO3)2 in water, which can be removed after boiling. It is called carbonate hardness, also known as temporary hardness.

(11) Permanent hardness. The hardness formed by salt substances such as CaSO4 (CaCl2) and MgSO4 (MgCl2) in water, which can not be removed after boiling. It is called non carbonate hardness, also known as permanent hardness.

(12) Solute. It exists in water (or other solvents) as simple molecules or ions. The particle size is usually only a few tenths to a few nanometers. It is invisible to the naked eye and has no Tyndall phenomenon. It can not be seen by optical microscope.

(13) Colloid. It is a group of particles formed by several molecules or ions. Its size is usually in the range of tens of nanometers to tens of microns. Which is invisible to the naked eye, but Tyndall phenomenon occurs. The small colloidal particles can not be seen by optical microscope, the large colloidal particles can be seen.

(14) Suspended matter. It is formed by the combination of a large number of molecules or ions. Its size is usually more than tens of microns. It can be clearly seen by optical microscope. The suspended particles can be precipitated after standing for a long time.

(15) Total salt content. The total amount of ions in water is called total salt content. It is obtained by adding up the total amount of cations and anions. The unit is expressed in terms of mg/L (also used to be ppm).

(16) Turbidity. It is an alternative parameter to reflect the content of suspended matter in water. The main suspended matter in water is usually soil. The standard turbidity unit is 1mg silica in 1L distilled water, expressed as 1PPm.

(17) TDS. It is also known as total dissolved solids, it is measured in milligrams per liter (mg/L). It indicates how many milligrams of dissolved solids are dissolved in 1 liter of water.

(18) Resistance. According to Ohm’s law, under the condition of constant water temperature, the resistance value of water is inversely proportional to the vertical cross-section area of the electrode, and is directly proportional to the distance between the electrodes.

(19) Conductance. The conductivity of water is called conductance.

(20) Electrical conductivity. The reciprocal of the resistance of water, is usually used to indicate the purity of water.

(21) Resistivity. It refers to the resistance between the two opposite sides of the cube water with a side length of 1cm at a certain temperature. Its unit is Ω*cm, which is generally used to indicate the quality of high-purity water.

(22) Softened water. It refers to the water in which the hardness (mainly refers to calcium and magnesium ions) is removed or reduced. In the process of water softening, only the hardness of water decreases, but the total salt content remains the same.

(23) Desalted water. It refers to the water in which salts (mainly strong electrolytes dissolved in water) are removed or reduced to a certain extent. Its conductivity is generally 1.0-10.0 us/cm, resistivity (25℃) is 0.1-1000000Ω.cm, and the salt content is 1.5mg/L.

(24) Pure water. It refers to the water in which the strong electrolytes and weak electrolytes (such as SiO2, CO2, etc.) are removed or reduced to a certain extent. The conductivity is generally 0.1-1.0us/cm, and the resistivity is 1.0-1000000Ω.cm, and the salt content is less than 1mg/L.

(25) Ultrapure water. It refers to water in which the conductive medium is almost completely removed, and the non-dissociated gas, colloid and organic matter (including bacteria, etc.) are also removed to a very low level. Its conductivity is generally 0.1-0.055μs/cm, resistivity (25℃)>10×1000000Ω.cm, and salt content <0.1mg/l. Ideal pure water (theoretically) has a conductivity of 0.05μs/cm and a resistivity (25℃) of 18.3×1000000μs/cm.

(26) Deoxygenated water. It refers to water that has been freed of dissolved oxygen. It is generally used for boiler water.

(27) Ion exchange. It refers to a separation method that utilizes the difference in ion exchange capacity between the exchangeable groups in the ion exchanger and the various ions in the solution.

(28) Cationic resin. It has acidic groups. In aqueous solution, the acidic groups can ionize to generate H+, which can exchange ions with cations in water.

(29) Anionic resin. It has basic groups. It ionizes in aqueous solution and exchanges ions with anions.

(30) Inert resin. It has no active groups and no ion exchange effect. The relative density is generally controlled between the anion and cation resins to separate the anion and cation resins, avoid cross contamination between the anion and cation resins during regeneration, and make the regeneration more complete.

(31) Microfiltration. Also known as microporous filtration, it is a kind of precision filtration. Microfiltration can filter out micron- or nano-sized particles and bacteria in the solution.

(32) Ultrafiltration. One of the membrane separation technologies driven by pressure. The purpose is to separate large molecules from small molecules. The membrane pore size is between 20-1000A°.

(33) Nanofiltration. It is a pressure-driven membrane separation process between reverse osmosis and ultrafiltration. The pore size of the nanofiltration membrane ranges from a few nanometers.

(34) Osmosis. It is the phenomenon of water molecules diffusing through a semipermeable membrane. It penetrates from a high water molecule area (i.e., low concentration solution) into a low water molecule area (i.e., high concentration solution).

(35) Osmotic pressure. For a semipermeable membrane with different aqueous solution concentrations on both sides, the minimum additional pressure applied on the high concentration side to prevent water from penetrating from the low concentration side to the high concentration side is called osmotic pressure.

(36) Reverse osmosis. It is to pressurize water from a concentrated solution to a low-concentration solution through artificial pressure. The pore size of the RO reverse osmosis membrane is as small as nanometers. Under a certain pressure, water molecules can pass through the RO membrane, while inorganic salts, heavy metal ions, organic matter, colloids, bacteria, viruses and other impurities in the source water cannot pass through the RO membrane.

(37) Dialysis. A membrane separation operation driven by concentration difference, using the selective permeability of the membrane to solutes to achieve the separation of solutes of different properties.

(38) Electrodialysis. It refers to the phenomenon that charged solute particles (such as ions) in a solution migrate through a membrane when dialysis is carried out under the action of an electric field.

(39) EDI, also known as continuous electro-desalting technology, is a pure water manufacturing technology that combines ion exchange technology, ion exchange membrane technology and ion electromigration technology.

(40) Recovery rate. It refers to the percentage of feed water converted into produced water or permeate in the membrane system.

(41) Desalination rate. It refers to the percentage of total soluble impurities removed from the system influent through the reverse osmosis membrane, or the percentage of specific components such as divalent ions or organic matter removed through the nanofiltration membrane.

(42) Salt permeability. The opposite value of desalination rate, which is the percentage of soluble impurities in the influent that pass through the membrane. Permeate: Purified water produced by the membrane system.

(43) Flux. It refers to the flow rate of permeate per unit membrane area, usually expressed in liters per square meter per hour (l/m2h) or gallons per square foot per day (gfd).

(44) Product water. It refers to the purified aqueous solution, which is the water produced by the reverse osmosis or nanofiltration system.

(45) Concentrated water. It refers to the part of the solution that passes through the membrane, such as the concentrated water of the reverse osmosis or nanofiltration system.