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Removal method of total nitrogen and ammonia nitrogen

来源:From the network      Release time:2022-05-31       Number of readings:


The concept of total nitrogen and ammonia nitrogen

The nitrogen entering the water body is mainlyInorganic nitrogenOrganic nitrogen之分。

Inorganic nitrogen includes ammonia nitrogen (referred to as ammonia nitrogen) and nitrate nitrogen。Ammonia nitrogen includes free ammonia nitrogenNH3-NAnd ammonium nitrogenNH4+-N;Nitrate nitrogen includes nitrate nitrogenNO3--NAnd nitrite nitrogenNO2--N。

Organic nitrogen mainly includes urea, amino acid, protein, nucleic acid, uric acid, fatty amine, organic base, amino sugar and other nitrogen-containing organic matter。Soluble organic nitrogen is mainly in the form of urea and protein,It can be converted to ammonia nitrogen by actions such as ammoniation。


Total nitrogen refers to the nitrogen content in soluble and suspended particles (usually measured nitrate nitrogen, nitrite nitrogen, inorganic ammonium salt, dissolved ammonia and other organic nitrogen compounds in the sum of nitrogen)。Soluble total nitrogen refers to water soluble and containing filterable solids (less than 0.45μm particulate matter) nitrogen content。Total nitrogen is one of the important indexes to measure water quality。

Determination method of total nitrogen:一是Organic nitrogen and inorganic nitrogen compounds (ammonia nitrogen, nitrite nitrogen, nitrate nitrogen) were determined and then added together。二是After oxidizing with potassium persulfate to convert organic nitrogen and inorganic nitrogen into nitrate, the nitrate ion in the solution is measured by ion selective electrode method, and can also be determined by ultraviolet method or reduction to nitrite, azo colorimetry, and ion chromatography。

1.2 氨氮

Ammonia nitrogen refers to free ammonia (or non-ionic ammonia),NH3Or ionic ammonia(NH4+Ammonia exists in form。Higher pH and higher proportion of free ammonia;On the contrary, the proportion of ammonium salt is high。
Ammonia nitrogen is a nutrient in water, which can lead to water eutrophication and is the main oxygen consuming pollutant in water.Toxic to fish and some aquatic organisms。
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。Ammonia toxicity is closely related to pH value and water temperatureIn general, the higher the pH value and water temperature, the stronger the toxicity。

Two approximate sensitivity colorimetric methods commonly used to determine ammonia are the classical Nessler reagent method and the phenol-hypochlorite method.Titration and electrode methods are also commonly used to determine ammonia;When the ammonia nitrogen content is high, the distillation titration method can also be used。(National standards include Nath's reagent method, salicylic acid spectrophotometry, distillation - titration method)


How to deal with total nitrogen and ammonia nitrogen?

2.1 Use nitrogen removal process

2.1.1The traditional process of denitrification by activated sludge

Under the action of various microorganisms, the traditional biological method converts ammonia nitrogen in wastewater into nitrogen through a series of reactions such as nitrification and denitrification, so as to achieve the purpose of wastewater treatment。Such processes includeBarth proposed three stage activated sludge method, two stage activated sludge method and other processes。

2.1.2 Anoxic-aerobic activated sludge denitrification system (A/O method)

The anoxic-aerobic activated sludge denitrification system (A/O method) was developed in the early 1980s and has been widely used at present。Compared with the two-stage activated sludge process, this process sets the anoxic denitrification reactor in front of the aerobic reactor, so it is often called "preemptive denitrification biological nitrogen removal system".The processing process is shown in the figure below。


2.1.3Other biological nitrogen removal processes

(1) Oxidation ditch process

Due to the operation process characteristics of the oxidation ditch, aerobic zone and anoxic zone will be formed in different parts of the reaction ditch, so that the activated sludge in the oxidation ditch passes through the aerobic zone and anoxic zone respectively.Thus, biological nitrogen removal can be realized。

(2) Biological turntable biological nitrogen removal process

Control the operating conditions of each stage of biological turntable,Put them in an aerobic state and anoxic state respectively,That is, aerobic biological turntable and anaerobic biological turntable need to be used respectively in the whole process,BOD removal and nitration of ammonia nitrogen were achieved in different aerobic biological turntables,In the anaerobic biological turntable, denitrification is mainly realized,The principle is similar to the above-mentioned three-stage activated sludge biological denitrification process,Only in this process to achieve all levels of function is to rely on the biological turntable to complete。

2.2 Utilization OrganismsStrain treatment

The use of some biological strains can also play a certain role in the degradation of total nitrogen and ammonia nitrogen, but the daily maintenance needs are relatively large.Generally, it is necessary to arrange long-term technical personnel to operate on site。

2.3 Treatment with chemical agents - ammonia nitrogen remover

First test the concentration of total nitrogen and ammonia nitrogen, if the concentration difference is not large, ammonia nitrogen removal agent can be directly used in the case of ammonia nitrogen concentration below 200mg/L, and the dosage is determined according to the water quantity on site.So when you get rid of the ammonia, the total nitrogen will go down。

Source: From the Internet