What is ammonia nitrogen and how to remove ammonia nitrogen exceeding the standard
——What is ammonia nitrogen? Ammonia nitrogen refers to ammonia in the form of free ammonia (or non-ionic ammonia, NH3) or ionic ammonia (NH4+). The higher the pH, the higher the proportion of free ammonia; conversely, the higher the proportion of ammonium salts. The main harmful effect of ammonia nitrogen on aquatic organisms is free ammonia, whose toxicity is dozens of times greater than that of ammonium salt, and increases with the increase of alkalinity. The toxicity of ammonia nitrogen is closely related to the pH value and water temperature of the pool water. In general, the higher the pH value and water temperature, the stronger the toxicity. The colorimetric methods commonly used to determine ammonia are the classic Nessler's reagent method and phenol-hyposine salt method; titration and electro-J method are also commonly used to determine ammonia; when the content of ammonia nitrogen is high, the national standard Nessler's reagent can also be used method, salicylic acid spectrophotometry, distillation-titration method. 2. How to remove ammonia nitrogen exceeding the standard? Low temperature in winter leads to lower water temperature, which affects the effect of biochemical treatment. The methods of reducing ammonia nitrogen in winter can be divided into physical and chemical methods, biochemical combined methods and new biological denitrification methods. 1. Physicochemical method Physicochemical method can be divided into: stripping method (under alkaline conditions, utilizing the gas-liquid equilibrium relationship between the gas-phase concentration and liquid-phase concentration of ammonia nitrogen to separate), zeolite deamination method (using cations in zeolite and NH4+ in wastewater is exchanged to achieve the purpose of denitrification), membrane separation technology (remove ammonia nitrogen by using the selective permeability of membrane), chemical oxidation method (use strong oxidant to directly oxidize ammonia nitrogen into nitrogen for removal) Method. 2. Combined biochemical method The physical and chemical method will not be limited by the high concentration of ammonia nitrogen in the treatment of high-concentration ammonia nitrogen wastewater, but it cannot reduce the concentration of ammonia nitrogen to a low enough level (such as below 100 mg/lL). Biological denitrification can be affected by high concentrations of free ammonia or nitrite nitrogen. In practical application, the method of biochemical combination is adopted, and the wastewater containing high concentration of ammonia nitrogen is subjected to physical and chemical treatment before biological treatment. 3. New biological denitrification method The new biological denitrification method can be divided into: whole process nitrification and denitrification (currently used for a long time A biological method is to convert the ammonia nitrogen in the wastewater into nitrogen gas through a series of reactions such as nitrification and denitrification under the action of various microorganisms, so as to achieve the purpose of wastewater treatment)) anaerobic ammonium oxidation and full autotrophic denitrification (Referring to the process in which ammonia nitrogen is directly oxidized into nitrogen gas with nitrite as the electron acceptor under anaerobic conditions), aerobic denitrification. GNST-900S Ammonia Determination Instrument meets the national standard 'HJ535-2009 Determination of Ammonia Nitrogen in Water Quality by Nessler's Reagent Spectrophotometry'. It uses optical fiber detection technology, medical imported light source, double colorimetric detection system, and humanized operation interface guidance. Design, the user can operate the instrument according to the text and voice prompts. The instrument has stable performance, accurate measurement, wide measurement range, powerful functions, and simple operation; it can directly measure ammonia nitrogen water quality testing.