What do you not know about domestic sewage testing

Domestic sewage is the wastewater discharged from residents' daily life, mainly from residential buildings and public buildings, such as residences, institutions, schools, hospitals, shops, public places and industrial enterprise toilets. The pollutants contained in domestic sewage are mainly organic matter and a large number of pathogenic microorganisms. Due to the unstable organic matter present in domestic sewage, it is easy to rot and produce stench. Bacteria and pathogens reproduce in large numbers using organic matter in domestic sewage as nutrients, which can lead to the spread of infectious diseases. Classification of Domestic Sewage According to the environmental functions and protection objectives of urban sewage treatment plants discharged into surface waters, as well as the treatment process of sewage treatment plants, the standards for routine pollutants in basic control items are divided into standard, secondary standard, and tertiary standard. Standards are divided into Standard A and Standard B. a. Standard A of the standard is the basic requirement for the effluent of urban sewage treatment plants to be used as reused water. When the effluent of the sewage treatment plant is introduced into rivers and lakes with a small dilution capacity for urban landscape water and general reuse water, standard A of the standard shall be implemented. b. When the effluent of urban sewage treatment plants is discharged into the second-class functional waters of GB3838 surface water (except for the designated drinking water source protection area and swimming area), the second-class functional waters of GB3097 seawater, and closed or semi-enclosed waters such as lakes and reservoirs, the implementation Standard Class B standard. c. The effluent of urban sewage treatment plants is discharged into the functional waters of GB3838 surface water IV and V or the seawater of GB3097 functional seas of III and IV, and the secondary standard shall be implemented. d. Sewage treatment plants in organized towns in non-controlled watersheds and non-water source protection areas, according to local economic conditions and water pollution control requirements, implement the third-level standard when adopting enhanced treatment processes, but the location of the second-level treatment facilities must be reserved. Staged up to the second standard. NO.2 Domestic sewage testing standard 'Comprehensive sewage discharge standard' GB8978-1996 'Water quality standard for sewage discharged into urban sewers' CJ3082-99 'Pollutant discharge standard for urban sewage treatment plants' GB18918-2002 NO.3 Domestic sewage testing item 1. Chemical Oxygen Demand High chemical oxygen demand means that the water contains a lot of reducing substances. The higher the chemical oxygen demand, the more serious the organic pollution of sewage. 2. Biochemical Oxygen Demand The aerobic microorganisms in the water body decompose the organic matter in the water into inorganic matter at a certain temperature. The amount of dissolved oxygen required in the oxidation process within a specific time indicates the content of aerobic pollutants such as organic matter in the water. a comprehensive indicator. 3. Suspended matter Solid matter suspended in water, including insoluble inorganic matter, organic matter, mud sand, clay, microorganisms, etc. The content of suspended solids in water is one of the indicators to measure the degree of water pollution. 4. The total number of bacteria refers to the total number of bacterial colonies grown in the sewage water sample in the nutrient agar medium after being cultured at 37 degrees Celsius for 24 hours. 5. Total phosphorus After the water sample is digested, various forms of phosphorus are converted into orthophosphate. The result is measured in milligrams of phosphorus per liter of water sample. 6. Coliform bacteria refers to a group of bacteria related to fecal pollution with certain characteristics. These bacteria are not completely consistent in biochemistry and serology. It is defined as: aerobic and facultative anaerobic, able to Gram-negative bacteria that break down lactose to produce acid and gas.