In our daily life, we often come into contact with water treatment, such as pure water we drink in our life, ultra-pure water used in industry, urban sewage treatment, etc., and the object we want to treat is the object we want to express, so how do we express these pollutants?
Solid pollutants: pollutants existing in water in solid form, including suspended state, colloidal state and dissolved state.
Suspended matter: solid matter with particle size below 1nm, mainly in low molecular or ionic state.
Turbidity: suspended solids and colloidal substances such as soil, silt, fine organic matter, inorganic matter and plankton in water can make the water quality turbid and present a certain turbidity. According to the water quality analysis, the turbidity formed by 1mgSiO2 in 1L water is a standard turbidity unit, which is referred to as 1 degree for short.
Color and chroma: Color is a kind of color in waste water, which is usually described in words. Chroma refers to the color depth of wastewater. There are two ways to express chromaticity: ① Platinum-cobalt standard colorimetry: It is stipulated that the color depth produced by containing Pt1mg and Co0.5mg in 1L water is 1 degree. (2) Dilution multiple method: dilute the waste water with water according to a certain dilution multiple until it is close to colorless.
Biochemical oxygen demand (BOD): refers to the amount of dissolved oxygen consumed by microorganisms in the process of decomposing and oxidizing organic matter in water under certain conditions of temperature and time.
Chemical oxygen demand (COD): refers to the amount of oxygen consumed by oxidizing organic substances in wastewater with strong oxidants under certain conditions. commonly used oxidants are potassium permanganate and potassium dichromate.
Total oxygen demand TOD: refers to a certain amount of water sample vaporized at 900℃ in a special burner with platinum as catalyst, in which the organic matter burns, and then the oxygen reduction in the gas carrier is measured as the oxygen required for complete oxidation of the organic matter.
Total organic carbon TOC: the total organic carbon in water samples is measured by combustion method to reflect the total organic matter in water. Organic nitrogen: it is a water quality index reflecting the total amount of nitrogen-containing organic substances such as protein, amino acids and urea in water. It can be decomposed into NH4+, NH3, NO3-, NO2-, etc. NH4+ and NH3 are ammonia nitrogen, NO2- is nitrite nitrogen and NO3- is nitrate nitrogen. Total nitrogen TN: it is a water quality index including all contents from organic nitrogen to nitrate nitrogen.