阅读说明：本技术 一种利用甘氨酸作为释磷剂从含磷污泥中回收磷的方法 (Method for recovering phosphorus from phosphorus-containing sludge by using glycine as phosphorus release agent ) 是由 邱光磊 田煜程 陈航 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种利用甘氨酸作为释磷剂从含磷污泥中回收磷的方法；在厌氧条件下向富磷剩余污泥中加入外源甘氨酸,在不消耗甘氨酸的条件下,激发并实现污泥微生物细胞中聚合磷酸盐的分解与磷酸盐的释放,得到释磷后的混合液；将释磷后的混合液经静置,实现固液分离；固液分离后的富磷上清液,经pH调节或沉淀剂的加入,实现磷酸盐的沉淀,得到磷酸盐沉淀物；待磷酸盐沉淀物干燥后,即得到磷回收产品；磷酸盐回收后的含甘氨酸上清液可循环使用,进行下一批次污泥磷酸盐释放；本方法可通过调节混合液中甘氨酸浓度实现磷酸盐释放速率的调控,并可保证磷的高效、快速、充分释放,溶液中甘氨酸极少消耗,可进行循环使用。(The invention discloses a method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent; adding exogenous glycine into the phosphorus-rich excess sludge under an anaerobic condition, and exciting and realizing the decomposition of polymerized phosphate in sludge microbial cells and the release of phosphate under the condition of not consuming glycine to obtain a mixed solution after phosphorus release; standing the mixed solution after releasing the phosphorus to realize solid-liquid separation; the supernatant rich in phosphorus after solid-liquid separation is subjected to pH adjustment or the addition of a precipitator to realize the precipitation of phosphate, so as to obtain phosphate precipitate; after the phosphate precipitate is dried, a phosphorus recovery product is obtained; the glycine-containing supernatant after phosphate recovery can be recycled for the next batch of sludge phosphate release; the method can realize the regulation and control of the release rate of the phosphate by regulating the concentration of the glycine in the mixed solution, can ensure the efficient, rapid and sufficient release of the phosphorus, has little consumption of the glycine in the solution, and can be recycled.)

1. A method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent is characterized by comprising the following steps:

adding exogenous glycine into the phosphorus-rich excess sludge under an anaerobic condition, and exciting and realizing the decomposition of polymerized phosphate in sludge microbial cells and the release of phosphate under the condition of not consuming glycine to obtain a mixed solution after phosphorus release;

standing the mixed solution after releasing the phosphorus to realize solid-liquid separation;

the supernatant rich in phosphorus after solid-liquid separation is subjected to pH adjustment or the addition of a precipitator to realize the precipitation of phosphate, so as to obtain phosphate precipitate;

and drying the phosphate precipitate to obtain a phosphorus recovery product.

2. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent according to claim 1, wherein the phosphorus release agent comprises:

the glycine-containing supernatant after phosphate recovery can be recycled for the next batch of sludge phosphate release.

3. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent according to claim 2, wherein the phosphorus release agent comprises:

the addition amount of the glycine is as follows: until the final concentration of glycine in the mixed solution is 10-750 mg/L.

4. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent according to claim 3, wherein the phosphorus release agent comprises:

the content of dissolved oxygen in the phosphorus release process is less than 1 mg/L;

the mixed liquid is mixed in the phosphorus release process, and the stirring speed is 20-200 rpm.

5. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent according to claim 4, wherein the phosphorus release agent comprises:

the pH value is 5.5-9.5 in the phosphorus release process;

the phosphorus release reaction time is 0.5-12 h.

6. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent according to claim 5, wherein the phosphorus release agent comprises:

after the phosphorus release reaction is finished, performing standing solid-liquid separation on the sludge mixed solution, and discharging sludge concentrated at the bottom; standing for solid-liquid separation for 5-120 min;

and (3) recovering phosphorus from the phosphorus-containing supernatant after solid-liquid separation, and adjusting the pH of the mixed solution to 6.0-11.0.

7. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent according to claim 6, wherein the phosphorus release agent comprises:

the precipitator is one or more of calcium chloride, calcium sulfate, calcium oxide, magnesium sulfate, magnesium carbonate, magnesium oxide, ferric sulfate and ferric chloride.

8. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus releasing agent according to claim 7, wherein the phosphorus releasing agent comprises:

the reaction time of the precipitation is 2-120 min.

9. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus releasing agent according to claim 8, wherein the phosphorus releasing agent comprises:

and (3) drying the phosphate precipitate, namely exposing the phosphate precipitate in the air and naturally drying the phosphate precipitate to obtain a dry phosphorus recovery product.

10. The method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus releasing agent according to claim 9, wherein the phosphorus releasing agent comprises:

the glycine-containing supernatant can be recycled, which means that the supernatant after phosphate precipitation recovery is recycled and is continuously used as a phosphorus release agent released by phosphorus-containing sludge.

Technical Field

The invention relates to the field of sludge recycling technology and phosphorus resource recovery, in particular to a method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent.

Background

Phosphorus is an important water environment pollutant, and as a nutrient for plants, excessive concentration of phosphorus in a water body can stimulate excessive growth of cyanobacteria/algae, so that cyanobacterial bloom is caused, and water ecological health and drinking water safety are damaged.

As one of key control factors of water eutrophication, the safety threshold of phosphorus in water is as low as 0.05-0.1mg/L, and phosphorus removal is one of important tasks of urban sewage treatment.

In addition, phosphorus is also an important non-renewable resource. The main purpose of phosphorus is to increase grain production as a fertilizer, and currently, the world has proved that the phosphorus reserves are only enough to support the development of human for hundreds of years, and the exhaustion of phosphorus resources directly threatens grain safety. About more than 300 million tons of phosphorus are lost with sewage every year around the world, and the phosphorus in the sewage can be recovered to meet the current 15-20% of phosphorus resource demand.

The method realizes the high-efficiency removal and subsequent recovery of phosphorus in the urban sewage treatment process, and has great significance for protecting the health of a water environment ecosystem and realizing the sustainable utilization of phosphorus resources.

Enhanced biological phosphorus removal is one of the most widely adopted phosphorus removal processes in municipal sewage treatment plants at present. The system depends on the unique physiological metabolic characteristics of the phosphorus-accumulating bacteria: decomposing intracellular polyphosphate under an anaerobic condition to obtain energy, and taking small-molecule volatile fatty acid from sewage to convert the small-molecule volatile fatty acid into the small-molecule volatile fatty acid to be stored in cells; the method comprises the steps of degrading polyhydroxyalkanoate to obtain energy under aerobic conditions, excessively absorbing dissolved orthophosphate in water to synthesize polyphosphate, storing the polyphosphate in a cell body, and discharging phosphorus-rich cells out of a sewage treatment system along with excess sludge, thereby achieving the purpose of removing phosphorus. In the process, phosphate in the sewage is converted into cells by the phosphorus accumulating bacteria, so that low-concentration phosphate in the urban sewage is enriched, and a large amount of phosphorus-rich sludge is generated. How to release phosphorus element stored in phosphorus accumulating bacteria cells in sludge is a key technical problem to be solved.

Common technologies include sludge digestion and an external carbon source method. The sludge digestion method includes a physical method (high-pressure injection, microwave irradiation, heating method, etc.) and a chemical method (ozone oxidation method, chlorine oxidation method, acid hydrolysis method, alkali hydrolysis method, etc.).

However, the traditional methods have the problems of difficult phosphorus release of the sludge, insufficient phosphorus release, large energy consumption, high operating cost and the like.

For the external carbon source method, carbon sources need to be supplemented continuously, and improper addition of carbon sources easily causes waste of carbon sources and generation of excessive excess sludge.

The research shows that glycine as a phosphorus release agent can induce phosphorus release of phosphorus accumulating bacteria under anaerobic conditions and is hardly consumed, which means that glycine has the advantages of low consumption and recycling compared with the traditional carbon source. Therefore, the invention provides a low-cost and high-efficiency recovery method for phosphate in the phosphorus-rich excess sludge of the enhanced biological phosphorus removal system by using glycine as a phosphorus release agent.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings of the prior art and provide a method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent.

The method can realize the regulation and control of the release rate of the phosphate by regulating the concentration of the glycine in the mixed solution, can ensure the efficient, rapid and sufficient release of the phosphorus, has little consumption of the glycine in the solution, can be recycled, greatly saves the cost of the medicament compared with the traditional process, and realizes the release and recovery of the phosphate in the phosphorus-rich sludge with low energy consumption and low addition.

The invention is realized by the following technical scheme:

a method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent comprises the following steps:

adding exogenous glycine into the phosphorus-rich excess sludge under an anaerobic condition, and exciting and realizing the decomposition of polymerized phosphate in sludge microbial cells and the release of phosphate under the condition of not consuming glycine to obtain a mixed solution after phosphorus release;

standing the mixed solution after releasing the phosphorus to realize solid-liquid separation;

the supernatant rich in phosphorus after solid-liquid separation is subjected to pH adjustment or the addition of a precipitator to realize the precipitation of phosphate, so as to obtain phosphate precipitate;

after the phosphate precipitate is dried, a phosphorus recovery product is obtained;

the supernatant containing glycine after the phosphate is recovered can be recycled for the next batch of sludge phosphate release.

The addition amount of the glycine is as follows: until the final concentration of glycine in the mixed solution is 10-750 mg/L.

Active temperature regulation is not needed in the process of releasing phosphorus;

the content of dissolved oxygen is less than 1mg/L in the process of releasing phosphorus;

mixing the mixed solution in the process of releasing phosphorus, wherein the stirring speed is 20-200 rpm.

The pH value is 5.5-9.5 during the phosphorus release process; the reaction time is 0.5-12 h.

After the phosphorus release reaction is finished, performing standing solid-liquid separation on the sludge mixed liquor, and discharging the mixed sludge concentrated at the bottom; standing for solid-liquid separation for 5-120 min;

and (4) recovering phosphorus from the phosphorus-containing supernatant after solid-liquid separation, and adjusting the pH of the mixed solution to 6.0-11.0.

The precipitator is a medicament capable of providing calcium ions, magnesium ions or iron ions, and comprises one or more of calcium chloride, calcium sulfate, calcium oxide, magnesium sulfate, magnesium carbonate, magnesium oxide, ferric sulfate and ferric chloride.

The reaction time of the precipitation is 2-120 min.

And (3) drying the phosphate precipitate, namely exposing the phosphate precipitate in the air and naturally drying the phosphate precipitate to obtain a dry phosphorus recovery product.

The supernatant containing glycine can be recycled, which means that the supernatant after phosphate precipitation is recovered is recycled and is continuously used as a phosphorus release agent released by phosphorus-containing sludge, and a proper amount of glycine is added to ensure the concentration of glycine in the mixed solution if necessary.

Compared with the prior art, the invention has the following advantages and effects:

the traditional method for adding the carbon source to release phosphate from the phosphorus-rich sludge has the defects that the adding amount of the carbon source is difficult to control, so that the phosphorus release is incomplete or the carbon source is excessive, the carbon source needs to be added into each batch of sludge, and the adding amount is large.

The method has the advantages of simple and easy technical means, and compared with the traditional method for releasing phosphorus by adding an external carbon source, the method has the advantages of less addition amount of the phosphorus releasing agent (glycine), recyclable phosphorus releasing agent and controllable phosphorus releasing rate, and can effectively reduce the medicament cost and save the material consumption in the phosphorus recovery process.

Drawings

FIG. 1 shows the results of a phosphorus release and glycine uptake test of sludge at different glycine concentrations in the example of the present invention.

FIG. 2 shows the second results of the phosphorus release and glycine uptake tests of sludge at different glycine concentrations in the example of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

A method for recovering phosphorus from phosphorus-containing sludge by using glycine as a phosphorus release agent can be realized by the following steps:

and (3) putting the phosphorus-rich residual sludge mixed liquor (MLSS ═ 1.0g/L) into a closed reactor, respectively adding glycine to the final concentrations of 10mg/L, 25mg/L and 50mg/L, stirring for 80min in a closed manner at the stirring speed of 100rpm and the pH value of 7.25, and inducing phosphorus-accumulating bacteria to release phosphorus.

Standing the mixed solution for 30min after the reaction is finished, discharging sludge which is settled at the bottom and completely releases phosphorus, adjusting the pH value to 9.5 by using 0.5mol/L sodium hydroxide, stirring and mixing for 60min, and carrying out precipitation reaction on phosphate in the phosphorus-rich supernatant by combining calcium ions and magnesium ions in the supernatant;

and discharging the precipitate after the precipitation reaction from the bottom of the reactor, and drying the precipitate in the air to obtain a phosphorus recovery product.

And (4) recycling the supernatant containing the glycine after the phosphate precipitation is recovered, and introducing the sludge mixed liquor of the next batch.

In the present embodiment, the conditions of sludge phosphorus release and glycine uptake under different glycine concentrations are shown in fig. 1 and fig. 2;

the test results of fig. 1 and 2 show that:

the glycine effectively induces the phosphorus release reaction of phosphorus accumulating bacteria in the excess sludge, and meanwhile, the glycine is not ingested, consumed and degraded by microorganisms;

the phosphorus release rate is controlled by adjusting the concentration of glycine, and the phosphorus release rate and the concentration of glycine form a significant linear relation in an experiment under the condition that the concentration range of glycine in a mixed solution is 10-50 mg/L;

that is, the higher the glycine concentration, the greater the phosphorus release rate, and the shorter the phosphorus release time.

Therefore, the phosphorus recovery speed can be effectively controlled according to the conditions such as the sludge discharge amount, the size of the reactor and the like.

As mentioned above, the invention can realize the regulation and control of the release rate of phosphate by regulating the concentration of glycine in the mixed solution, can ensure the efficient, rapid and sufficient release of phosphorus, has little consumption of glycine in the solution, can be recycled, greatly saves the cost of the medicament compared with the traditional process, and realizes the release and recovery of phosphate in the phosphorus-rich sludge with low energy consumption and low addition.

The embodiments of the present invention are not limited to the above-described embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they are included in the scope of the present invention.