Energy-saving ammonia-nitrogen wastewater treatment method and device

Abstract

The invention discloses an energy-saving ammonia-nitrogen wastewater treatment method. According to the method, firstly, the pH (potential of hydrogen) value of ammonia-nitrogen wastewater is adjusted firstly, compounded ammonia in the ammonia-nitrogen wastewater is decomposed to free ammonia through mixed heat exchange and heating, free ammonia is conveyed to the upper part of an ammonia removal tower and flows into the lower part, meanwhile, high-temperature steam is conveyed from the lower part of the ammonia removal tower through a reboiler, ammonia-nitrogen wastewater and the high-temperature steam have steam-liquid contact in a medium in the ammonia removal tower, ammonia and nitrogen in the ammonia-nitrogen wastewater and the steam form ammonia-containing steam in an ammonia and nitrogen removal tower, the ammonia-containing steam is discharged from the top of the tower, and wastewater without ammonia is discharged from the bottom of the tower; the general concentration of the ammonia-containing steam discharged from the top of the ammonia removal tower is higher than 30%, the ammonia-containing steam is firstly condensed through cooling and collected in a condensate buffer tank, accordingly, ammonia water condensate is formed, the ammonia water condensate is conveyed into an ammonia water circulating tank intermittently through an ammonia water condensate pump, and ammonia water is prepared. By means of the method and the device, the removal rate of ammonia and nitrogen is higher than 99.9%, the operation is convenient, the working stability is good, the occupation area is small, and the operation cost is low; the content of ammonia and nitrogen is not higher than 100 mg / L, and the quality of discharged water is good.

Description

technical field [0001] The invention relates to an ammonia nitrogen treatment method, in particular to a treatment method and a treatment device for high-concentration ammonia nitrogen wastewater. Background technique [0002] With the rapid development and growth of chemical fertilizer, petrochemical, coking and other industries, the resulting high ammonia nitrogen wastewater has also become one of the restrictive factors for the development of the industry. At present, the more common way to deal with high-concentration ammonia-nitrogen wastewater in domestic and foreign production practices is to first reduce the ammonia-nitrogen in the wastewater to below 200mg / L by stripping or blowing off the high-concentration ammonia-nitrogen wastewater (if it cannot be reduced to below 300mg / L, It needs to be diluted with clean water), and then use A / O method or chemical precipitation method (magnesium ammonium phosphate method) for subsequent treatment. Effluent NH 3 -N under the...

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Problems solved by technology

[0003] 1) The continuous A / O method not only has high investment, but also occupies a large area, and has strict requirements on the pretreatment effluent (such as NH3-N must be less than 200mg / l, and the stripping or stripping method is suitable for high concentration of more than 2000mg / l) Ammonia nitrogen wastewater cannot meet this requirement at all, and can only be diluted with doubled water before treatment);

[0004] 2) Although the investment and floor area of ​​the continuous chemical precipitation method are smaller than the A / O method, the chemical consumption is too large, and the ratio of N:P:Mg is 1:1.1-1.2, the cost of the chemical treatment is too high, and The effluent cannot meet the national first-level or second-level discharge standards;

[0005] 3) In the current ammonia stripping treatment process, the stripping efficiency of ammonia nitrogen can only reach 85-90%, and ammonia stripping enters the atmosphere to cause secondary pollution

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