High-ammonia-nitrogen waste liquid purification process

A purification process, high ammonia nitrogen technology, applied in chemical instruments and methods, water/sewage multi-stage treatment, separation methods, etc. The effect of high elasticity and strong shock load resistance

Inactive Publication Date: 2021-07-09
DALIAN MARITIME UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Disclosed in CN106946420A is a high-concentration ammonia-nitrogen sewage treatment method. The invention combines blow-off method, advanced oxidation method and breakpoint chlorination method, which has the advantages of high ammonia nitrogen removal rate and strong process stability, but it will also cause short Saturation of time exchangers increases processing costs
However, this method needs to add a large amount of expensive coagulant, and the NaCl produced at the same time will affect the microbial activity of subsequent biological treatment

Method used

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  • High-ammonia-nitrogen waste liquid purification process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] 15L of waste liquid containing 4000mg / L of ammonia nitrogen is first pretreated by grille and sedimentation tank, and NaOH solution is added to the inlet pipe of the heat exchanger to adjust the pH to 11, and the temperature of high ammonia nitrogen waste liquid is raised to 65°C. Then it enters the plate blowing tower. The upper part of the blowing tower is equipped with a tubular liquid distributor, and the bottom of the tower is equipped with a blower to blow in circulating air for gas-liquid contact and mass transfer. The waste liquid at the bottom of the tower is discharged through the drainage pump, and undergoes crystallization, dehydration, and drying to obtain solid products and complete the recovery of ammonia nitrogen resources. The concentration of ammonia nitrogen in the effluent measured at this time was 120 mg / L, and the removal rate of ammonia nitrogen was about 97%.

Embodiment 2

[0037] 20L of waste liquid containing 6300mg / L of ammonia nitrogen is firstly pretreated by grille and sedimentation tank, and then KOH is added to the alkali addition tank with stirring to adjust the pH to 12, and then the temperature of high ammonia nitrogen waste liquid is raised to 70°C. After that, it enters the packed blow-off tower. The upper part of the blow-off tower is equipped with a trough-type liquid distributor, the tower is filled with Pall rings, and the bottom of the tower is equipped with a blower to blow in circulating nitrogen. Entering the absorption tower with pH=5, the waste liquid at the bottom of the stripping tower is discharged through the drainage pump, and undergoes crystallization, dehydration, and drying to obtain solid products and complete the recovery of ammonia nitrogen resources. The concentration of ammonia nitrogen in the effluent measured at this time was 125 mg / L, and the removal rate of ammonia nitrogen was about 98%.

Embodiment 3

[0039] 25L of ammonia nitrogen containing 5800mg / L waste liquid is first pretreated by grille and sedimentation tank, and NaOH solution is added to the inlet pipe of the heat exchanger to adjust the pH to 13, and the temperature of high ammonia nitrogen waste liquid is raised to 85°C. After entering the plate type stripping tower, the upper part of the stripping tower is equipped with a jet liquid distributor, and the bottom of the tower is equipped with a blower to blow in circulating nitrogen for gas-liquid contact mass transfer. The waste liquid at the bottom of the tower is discharged through the drainage pump, and undergoes crystallization, dehydration, and drying to obtain solid products and complete the recovery of ammonia nitrogen resources. The ammonia nitrogen concentration in the effluent measured at this time was 170mg / L, and the removal rate of ammonia nitrogen was about 97%.

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Abstract

The invention discloses a high-ammonia-nitrogen waste liquid purification process. A purification system for the process mainly comprises a grating, a sedimentation tank, a heat exchanger, a stripping tower and an absorption tower. The purification method comprises the following steps of: (1) pretreating the high-ammonia-nitrogen waste liquid through the grating and the sedimentation tank to separate impurities in the waste liquid, and then adding alkali to adjust the pH value; (2) heating the waste liquid in the step (1) in the heat exchanger; (3) enabling the waste liquid heated in the step (2) to enter the stripping tower to be in contact with circulating gas for mass transfer, efficiently stripping NH3 under a high-temperature condition, enabling the stripped waste liquid to enter the bottom of the tower to be discharged, or recycling the waste liquid after deep treatment; (4) enabling the circulating gas rich in ammonia nitrogen in the step (3) to enter the lower part of an absorption tower, transferring NH3 in the gas from a gas phase into sprayed absorption liquid under a gas-liquid phase balance condition, and reacting with acid in the absorption liquid to generate ammonium salt; and meanwhile, enabling the circulating gas becoming clean again to enter the stripping tower to be recycled; and (5) discharging the absorption liquid from the bottom of the tower, crystallizing, dehydrating and drying to obtain a solid product, thereby completing the recovery of ammonia nitrogen resources.

Description

technical field [0001] The invention belongs to the technical field of waste liquid purification, and in particular relates to a method for purifying high ammonia nitrogen waste liquid. Background technique [0002] Ammonia nitrogen waste liquid mainly comes from tail gas treatment waste liquid, farmland drainage, aquaculture wastewater, landfill leachate, coal chemical sewage or petrochemical sewage, etc. If it is not treated in time and directly discharged into the water body or stored in an inappropriate place, it will cause serious deterioration of the surface water or groundwater quality, and cause great harm to the environment and human health. [0003] At present, the main technologies for treating ammonia nitrogen waste liquid are: breakpoint chlorination method, ion exchange method, electrodialysis method, catalytic wet oxidation method, chemical precipitation method, biological denitrification method, stripping method, etc. The breaking point chlorine addition met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/10B01D53/58B01D53/78C02F101/16
CPCC02F9/00B01D53/58B01D53/78C02F1/001C02F2001/007C02F1/02C02F1/20C02F1/66C02F2101/16Y02A50/20
Inventor 孙天军李云赫李涵清梁培远邵秘华赵宝刚
Owner DALIAN MARITIME UNIVERSITY
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