Views: 19 Author: Xicheng Ep Ltd Publish Time: 2021-08-28 Origin: Xicheng Ep Ltd
At present, the treatment methods commonly used in the industry to treat low-concentration ammonia nitrogen mainly include chemical agent method, adsorption method, breaking point chlorination method, biological method, and stripping method.
Ammonia nitrogen remover mainly achieves the removal effect by oxidizing and decomposing ammonia nitrogen in water:
The removal rate is as high as 96% or more;
At the same time, it also has the auxiliary function of decolorization and COD reduction, and can also adjust the pH value to save the cost of acid adjustment;
Furthermore, the reaction speed is fast, and the reaction is complete in about 5-6 minutes;
The ammonia nitrogen remover can be directly added to the sedimentation tank in the original process without additional equipment and processes, which greatly reduces the cost.
Adsorption methods often use porous solids as adsorbents, which can be divided into physical adsorption, chemical adsorption and exchange adsorption according to different adsorption principles.
However, due to the limited exchange capacity of the ion exchanger, frequent regeneration is required, and the ammonia nitrogen removal effect gradually decreases after regeneration, resulting in the ion exchanger must be replaced after multiple regenerations; in addition, the exchange capacity of the ammonia nitrogen is easily affected by other cations in the wastewater, so Environmentalists who use this method should first understand.
Breakpoint chlorination is one of the denitrification processes in sewage treatment projects. Its principle is a chemical process in which chlorine gas is passed into ammonia nitrogen wastewater to a certain critical point, and ammonia nitrogen is oxidized to nitrogen.
Here we need to remind the environmentalists who use this method:
Chlorine produced by the interaction of chlorine and ammonia nitrogen in water will cause secondary pollution;
The chlorine consumption is large, and the safe use and storage cost of liquid chlorine is high
The pH requirements of the water quality are harsh, and the acidic wastewater produced needs to be neutralized by alkaline substances to meet the discharge standards, which increases the operating cost of treating ammonia nitrogen wastewater.
Biological method means that the ammonia nitrogen in wastewater is generated by a series of reactions such as nitrification and denitrification under the action of various microorganisms, so as to achieve the purpose of removal.
However, because the biological method is affected by temperature, the treatment efficiency is low at low temperature, it takes a long time, covers a large area, and has a large oxygen demand. Some harmful substances such as heavy metal ions have an inhibitory effect on microorganisms and need to be removed before the biological method. . So personally do not recommend it.
The stripping method uses the difference between the actual concentration of volatile substances such as ammonia (NH3) and the equilibrium concentration to adjust the pH of the wastewater to alkaline, using air or other gases as the carrier gas and passing it into the stripping tower. After the gas-liquid two phases are fully contacted, the gas dissolved in the wastewater and NH3 enter the gas phase from the liquid phase through the gas-liquid interface, so as to achieve the purpose of removing ammonia nitrogen in the wastewater.
Pay attention to when using the blow-off method:
If it is necessary to add alkali to adjust the pH of the wastewater to above 11 before stripping, and then add an appropriate amount of acid to adjust the pH to below 9 after stripping, the consumption of acid and alkali will be large and the treatment cost will be increased;
In addition, for industrial wastewater with complex components, whether it is stripping or stripping, precipitation is prone to occur during the stripping process with the addition of alkali, leading to the problem of tower blockage.