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Targeted clean extraction method for sludge phosphorus recovery

An extraction method and phosphorus recovery technology, applied in the field of sludge resource utilization, can solve the problems of low extraction efficiency of activated sludge, sludge can not be used directly as phosphate fertilizer, increase the complexity of phosphorus recovery process, etc., and achieve broad market application prospects, Important social and environmental benefits, the effect of little metal element interference

Active Publication Date: 2021-07-09
TONGJI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these sludges are also enriched with a large number of organic pollutants, pathogenic microorganisms, heavy metals and other substances in sewage. Therefore, sludge cannot be used directly as phosphate fertilizer, and the release of phosphorus becomes an important prerequisite for sludge phosphorus recovery.
[0004] Acid dissolution is a simple and effective sludge phosphorus extraction technology, but the co-dissolution of metals leads to subsequent phosphorus recovery, which needs to be separated and purified by ion exchange resin and other methods, which increases the complexity of the phosphorus recovery process
In addition, a large number of current research data show that acid dissolution can effectively extract inorganic phosphorus in sludge, and the extraction efficiency of digested sludge with high inorganic phosphorus content is more than 80%, but the extraction efficiency of activated sludge with high organic phosphorus content low

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  • Targeted clean extraction method for sludge phosphorus recovery

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Effect test

Embodiment 1

[0032] The sludge used in this embodiment is the remaining activated sludge of Shanghai Bailonggang Sewage Treatment Plant for biological phosphorus removal, its total solids (TS) and volatile solids (VS) are 2.45% and 1.47% respectively, and the total phosphorus content is about 23.92mg / g TS, the phosphorus content in the supernatant is about 40mg / L.

[0033] Add 1.225 g of acidic ion exchange resin to 50 g of sludge, and shake it on a shaker at 200 rpm for 4 hours at room temperature. After the reaction, the pH of the sludge drops to 2.3. Utilize 55 purpose stainless steel sieves to obtain ion-exchange resin and sludge respectively, sludge is carried out centrifugal filtration, in filtrate, add calcium chloride, make Ca / P mol ratio in filtrate be 1.5:1, utilize 3M sodium hydroxide to adjust pH to 9. Stir at 200rpm for 30 minutes, let stand for precipitation for 30 minutes, and recover phosphorus in the form of calcium phosphate precipitation, and finally clean and regenerate...

Embodiment 2

[0039] The sludge used in this example is the remaining activated sludge of a sewage treatment plant in Suzhou, where TS=2.40%, VS=1.56%, the total phosphorus content is about 24.64mg / gTS, and the phosphorus content in the supernatant is about 30mg / L.

[0040] Add 1.2 g of acidic ion exchange resin to 50 g of sludge, and shake it on a shaker at 200 rpm for 4 hours at room temperature. After the reaction, the pH of the sludge drops to 2. Utilize 55 purpose stainless steel sieves to obtain ion-exchange resin and sludge respectively, sludge is carried out centrifugal filtration, in filtrate, add calcium chloride, make Ca / P mol ratio in filtrate be 1.5:1, utilize 3M sodium hydroxide to adjust pH to 9. Stir at 200rpm for 30 minutes, let stand for precipitation for 30 minutes, and recover phosphorus in the form of calcium phosphate precipitation, and finally clean and regenerate the used ion exchange resin with 5% hydrochloric acid.

Embodiment 3

[0045] The sludge used in this implementation is the mixed sludge of biological phosphorus removal activated sludge and iron salt enhanced phosphorus removal chemical sludge in a sewage treatment plant in Suzhou, where TS=2.50%, VS=1.52%, and the total phosphorus content is about 24.50mg / g TS, the phosphorus content in the supernatant is about 35mg / L.

[0046] 1.25 g of acidic ion exchange resin was added to 50 g of sludge, and shaken on a shaker at 200 rpm for 4 hours at room temperature. After the reaction, the pH of the sludge dropped to 2.5. Utilize 55 purpose stainless steel sieves to obtain ion exchange resin and sludge respectively, carry out centrifugal filtration to sludge, add calcium chloride in filtrate, make Ca / P mol ratio in filtrate be 2:1, utilize 3M sodium hydroxide to adjust pH to 8. Stir at 200rpm for 30 minutes, let stand for precipitation for 30 minutes, and recover phosphorus in the form of calcium phosphate precipitation, and finally clean and regenerate...

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Abstract

The invention relates to a targeted clean extraction method for sludge phosphorus recovery, which comprises the following steps: (1) targeted extraction of phosphorus: adding acidic ion exchange resin into sludge, and conducting stirring to fully extract inorganic phosphorus and organic phosphorus in the sludge; (2) ion exchange resin regeneration: sieving a mixture of the sludge and the resin in the step (1), respectively collecting the sludge and the resin, regenerating the resin by using a strong acid regeneration liquid, and recycling the regenerated resin in the step (1); and (3) cleaning and recycling of phosphorus: centrifuging the sludge obtained in the step (2), respectively collecting residual sludge and supernate, adding calcium salt into the supernate, then adjusting the pH value, and cleaning and recycling phosphorus in the sludge in the form of calcium phosphate. Compared with the prior art, the method has the advantages of high release rate of phosphorus, small interference of metal elements, recyclability of resin and the like.

Description

technical field [0001] The invention relates to the technical field of sludge resource utilization, in particular to a targeted cleaning and extraction method for sludge phosphorus recovery. Background technique [0002] As a biologically necessary and non-renewable resource, the long-term stable supply of phosphorus has attracted widespread attention from all mankind. According to the statistics of the United States Geological Survey, the consumption of phosphate rock is growing at an average rate of more than 2% per year. In 2019, the world’s phosphate rock mining volume is about 240 million tons. ) and the consumption rate, the world's phosphate rock resources will be completely consumed within 280 years. Therefore, the recovery of phosphorus resources has become a strategic demand for global sustainable development. [0003] As a misplaced resource, sludge is an important source of phosphorus recovery. According to incomplete statistics, about 1.3 million tons of phos...

Claims

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Application Information

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IPC IPC(8): C02F11/00C02F11/127C01B25/32C02F101/10
CPCC02F11/00C02F11/127C01B25/32C02F2209/18C02F2101/105C02F2209/06C02F2101/203C02F2101/20C02F2101/10
Inventor 戴晓虎丁燕燕武博然
Owner TONGJI UNIV