Method for recovering phosphorus from urban mud anaerobic digestion solution

An anaerobic digestion and municipal sludge technology, applied in the field of phosphorus recovery, can solve the problems of not finding, low utilization efficiency of calcium source, and high recovery cost, and achieve the effects of reducing phosphorus load, expanding utilization channels, and reducing costs.

Active Publication Date: 2009-11-25
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

The recovery of phosphorus in the crystal form of ammonium magnesium phosphate needs to find an economical and suitable source of magnesium, and at the same time determine the appropriate recovery process conditions to obtain a higher phosphorus recovery rate and a product with a high phosphorus content. This aspect needs further research; Phosphorus recovery in the form of salt precipitation requires an ideal calcium source, Ca(OH) 2 The utilization efficiency of emulsion as a calcium source is low, while CaCl 2 As a calcium source, the recovery cost is relatively high, so an ideal calcium source has not been found so far

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  • Method for recovering phosphorus from urban mud anaerobic digestion solution
  • Method for recovering phosphorus from urban mud anaerobic digestion solution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Take the fly ash from power plant A. After testing, the content of f-CaO in the fly ash is 1.70-3.40%. Mix fly ash and water at a ratio of 1:5, stir at 400rpm for 4h; let it stand for 16h, take the supernatant, filter the suspended particles with a filter membrane with a pore size of 0.45 microns, and obtain a leachate; after determination, Ca in the leachate 2+ The concentration reaches 1500.0mg / L.

[0034] After anaerobic digestion of municipal sludge, the supernatant was taken. After testing, the initial total phosphorus concentration was 94.5mg / L, and the initial orthophosphorus concentration was 89.0mg / L. Pretreatment was carried out, that is, the filter membrane with a pore size of 0.45 microns was used to filter and remove Suspend the particles, then add hydrochloric acid with a concentration of 5.9mol / L to acidify, adjust the pH value of the solution to 4.0, and obtain a pretreated digestive juice.

[0035] Mix the leaching solution and the pretreated digestive...

Embodiment 2

[0038] Take the fly ash from power plant B, and it is tested that the content of f-CaO in the fly ash is 1.70-3.40%. Mix fly ash and water at 1:40, stir at 50rpm for 0.5h; let it stand for 10h, take the supernatant, filter with a filter membrane with a pore size of 0.45 microns to remove suspended particles, and obtain a leachate; wherein, Ca in the leachate 2+ The concentration reached 640.0mg / L.

[0039] After anaerobic digestion of municipal sludge, the supernatant was taken. After testing, the initial total phosphorus concentration was 173.0mg / L, and the initial orthophosphorus concentration was 167.8mg / L. Pretreatment was carried out, that is, the filter membrane with a pore size of 0.45 microns was used to filter and remove Suspend the particles, then add hydrochloric acid with a concentration of 8.85mol / L to acidify, adjust the pH value of the solution to 3.8, and obtain the pretreated digestive juice.

[0040] According to the molar ratio of calcium and phosphorus in ...

Embodiment 3

[0043] Take the fly ash from power plant A. After testing, the content of f-CaO in the fly ash is 1.70-3.40%. Mix fly ash and water at a ratio of 1:20, stir at 200rpm for 1h; let it stand for 12h, take the supernatant, filter the suspended particles with a filter membrane with a pore size of 0.45 microns, and obtain a leachate; wherein, Ca in the leachate 2+ The concentration reached 1020.0mg / L.

[0044] After anaerobic digestion of municipal sludge, the supernatant was taken. After testing, the initial total phosphorus concentration was 107.6mg / L, and the initial orthophosphorus concentration was 105.9mg / L. Pretreatment was carried out, that is, the filter membrane with a pore size of 0.45 microns was used to filter and remove Suspend the particulate matter, then add hydrochloric acid with a concentration of 8.85mol / L to acidify, adjust the pH value of the solution to 2.0, and obtain a pretreated digestive juice.

[0045] Mix the leaching solution and the pretreated digestiv...

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Abstract

The invention discloses a method for recovering phosphorus from the urban mud anaerobic digestion solution, comprising: mixing and stirring the fly ash and water with the mass ratio of 1:5-40, standby, producing the leaching liquid; anaerobic digestion of the urban mud, taking the supernatant for acidification to regulate the pH value of the solution for preprocessing; mixing the leaching liquid and the preprocessed digestion liquid according to initial reaction calcium phosphorus molar ratio of 0.5-3.3:1; regulating the reaction pH value to 7.5-11.0, stirring and reacting for 5-120 min; obtaining the calcium phosphate precipitates. The invention subtly utilizes the fly ash leaching solution to provide calcium source and recovers phosphorus in the mode of calcium phosphate, can recover the valuable products from the mud and the fly ash and relieve the phosphorus load in the subsequent sewage treatment. Because the leaching solution is enriched with hydroxyl ions, the alkali feed quantity is reduced and the recovered products has high purity.

Description

technical field [0001] The invention relates to a method for recovering phosphorus, in particular to a method for recovering phosphorus from municipal sludge anaerobic digestion liquid. Background technique [0002] As a non-renewable mineral resource, phosphate rock can only last for about 70 years in my country. The Ministry of Land and Resources has listed phosphate rock as one of the 20 kinds of ores that cannot meet the needs of national economic development after 2010. At the same time, phosphorus is one of the main factors that cause eutrophication of water bodies. As a large amount of phosphorus-containing domestic sewage and industrial wastewater are discharged into rivers and lakes, the nutrient content of water bodies increases. The direct consequence is eutrophication of water bodies, causing algae to grow wildly , leading to the death of fish, shellfish and other aquatic animals due to lack of oxygen, thereby accelerating the aging process of the water body, ma...

Claims

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Application Information

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IPC IPC(8): C01B25/32
Inventor 梅翔王磊孙庆瑶陈建华王金梅黄河杨旭黄永胜
Owner NANJING FORESTRY UNIV
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