Deep denitrification process for wastewater

Abstract

The invention provides a deep denitrification process for wastewater. The deep denitrification process comprises the following specific steps of: firstly, performing microwave irradiation and coagulating sedimentation on the wastewater, wherein a certain quantity of NaOH is added into the high-concentration ammonia-nitrogen wastewater to adjust the pH value of the wastewater to 11-13, and a flocculant and a coagulant are added into the wastewater at an alkaline condition to perform the coagulating sedimentation, thus obtaining supernatant liquor; secondly, introducing the supernatant liquor obtained in the first step into an air stripping tower, wherein a sprayer is arranged at the top of the air stripping tower, multiple packing layers are arranged in the middle in a tower body, after passing through the sprayer, the wastewater becomes fine flow and flows through the packing layers, an air blower introduces air into the tower through an aeration port at the bottom of the tower, the air is in contact with the fine flow on the surface of packing, and exhaust for air stripping enters an absorption cell containing waste hydrochloric acid or waste sulphuric acid absorption liquid to absorb a part of ammonia nitrogen; thirdly, performing continuous circulating ammonia sedimentation on pyrolysis products of magnesium ammonium phosphate (MAP), and after the sedimentation of the MAP, processing effluent by a biological nitrogen removal process; fourthly, performing anaerobic (A)-anoxia (4)-oxic (O) biological nitrogen removal process on the effluent in the third step; and fifthly, performing denitrification on the left less nitrogen by a denitrification biofilter and a membrane filter. Therefore, ammonia nitrogen and total nitrogen of the effluent of the processed wastewater can reach a first-level A standard in the discharge standard of pollutants for municipal wastewater treatment plants (GB18918-2002).

Description

technical field [0001] The invention relates to a wastewater deep denitrification process, which belongs to the technical field of sewage treatment. Background technique [0002] In recent years, with the development of industry and agriculture, the problem of eutrophication of water bodies has become increasingly prominent, and the impact of ammonia nitrogen wastewater on the environment has attracted great attention in the field of environmental protection worldwide. [0003] At present, my country's ammonia nitrogen wastewater has expanded from cities to rural areas, and non-point source pollution is becoming more and more serious. Due to the lag in the construction of sewage treatment facilities, a large amount of untreated high-concentration ammonia nitrogen wastewater is directly discharged into ditches, rivers, and finally into lakes, etc. Water bodies have aggravated the pollution of the water environment. Most of the existing sewage treatment plants that have been b...

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Problems solved by technology

However, the removal mechanism of total nitrogen is mainly biological denitrification. It is difficult to find a simple and effective method to control the total nitrogen of the effluent. It can only be controlled by adjusting the process parameters and operating conditions, so the total nitrogen index is largely Affected the implementation of Class A standard in sewage plants

[0007] At present, most of the reasons why the total nitrogen index cannot meet the standard or cannot be upgraded to the first-level A standard are mainly due to the following points: the whole system has no denitrification function; the system has the denitrification function, but

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