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

23, organic pollution: refers to natural organic matter in the form of carbohydrates, proteins, amino acids and fats and other forms of some other biodegradable synthetic organic matter. It mainly comes from domestic sewage and industrial wastewater.

24, concentration polarization: Under the operating condition of reverse osmosis, the salt on the surface of the film is concentrated, and there is a concentration difference between the salt in the water, if the flow rate of concentrated water is small, the flow rate is low, the water with high content of salt can not be taken away in time, and a high concentration difference will be formed on the surface of the film, which hinders the diffusion of salt, this phenomenon is called concentration polarization.

25, suspended matter (SS) : refers to the solid substances suspended in water, including insoluble in water inorganic matter, organic matter and mud sand, clay, microorganisms, etc. The content of suspended matter in water is one of the indicators to measure the degree of water pollution. It is the amount of solid obtained by drying the intercepts on the filter paper at 103-105 degrees after the water sample is filtered. The unit is mg/l.

26, aeration: The process of transferring O2 in the air to the mixed liquid and being used by microorganisms. The purpose is to provide dissolved oxygen required by activated sludge and other microorganisms to ensure the oxygen demand of microbial metabolic processes.

27, biochemical oxygen demand (BOD) : refers to the dissolved oxygen consumed by microorganisms in the process of decomposition and oxidation of organic matter in water under the specified time, temperature 20 ° C, usually for 5 days, abbreviated BOD5, unit mg/L.

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

29, water hammer: also known as water hammer. In the process of water (or other liquids) transportation, due to the sudden opening or closing of the valve, the sudden stop of the pump, and the sudden opening and closing of the guide vane, the flow rate changes suddenly, and the pressure fluctuates greatly.

30, adsorption: refers to the use of porous solid adsorption of some or several pollutants in the wastewater to recover or remove some pollutants, so that the wastewater can be purified method.

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

32, sewage: sewage is a general term for water discharged in production and living activities. In human life and production activities, to use a large amount of water, these waters are often polluted to different degrees, the polluted water is called sewage.

33, sewage treatment: is the use of various technologies and means, the sewage contained in the separation of pollutants removal, recycling or conversion into harmless substances, so that the water is purified.

34, sewage reuse: sewage or waste water after secondary treatment and in-depth treatment back for production systems or domestic utility is called sewage reuse. When the treated water meets the specific reuse requirements and is reused, it can also be called reclaimed water.

35, scale: that is, due to the poor water quality of the boiler water, after a period of operation, the solid attachment generated on the pipe wall of the heating surface and water contact.

36, water slag: refers to the solid matter suspended in the furnace water and deposited in the drum, the bottom of the lower header and other slow flow of sediment. The difference from scale: the water slag is relatively loose, in suspension or sediment state, and some of it is easy to discharge with the boiler blowdown; The scale can be firmly bonded to the pipe wall and is not easy to discharge.

37, iron, manganese, aluminum: trace amounts of iron and manganese will create staining, scaling and taste problems, iron in the reduced state of the environment is in the form of water-soluble bivalent iron, when and air contact will gradually oxidize into yellow brown colloidal trivalent iron, and finally precipitated into brown iron hydroxide. The characteristics of manganese and iron are similar, because the oxides of iron, manganese and aluminum are also one of the reasons for scaling of RO film, it is necessary to analyze its content.

38, pure water: refers to the removal of the strong dielectric that is easy to remove in water, and the weak electrolyte such as silica acid and carbon dioxide that is difficult to remove to a certain degree of water. The salt content of pure water is less than 1.0mg/L, and the conductivity is less than 3μs/cm.

39, ultra-pure water: also known as high pure water, refers to the water conductive medium is almost all removed, and the water does not dissociate colloidal substances, gases and organic matter are removed to a very low degree of water. The salt content of ultra-pure water is less than 0.1mg/L, and the conductivity is less than 0.1μs/cm.