CN102775018A - Phosphorus removing and coupling process of sewage sludge treatment - Google Patents

Abstract

The invention discloses a phosphorus removal coupled phosphorus process for sewage sludge treatment, which converts phosphorus in sewage sludge into phosphine, and then absorbs phosphine to make it a resource. The sludge is discharged outside. The process includes the following operating procedures: anaerobic process of sewage sludge and anaerobic process of sewage sludge. After the phosphine gas generated in the above processes is dried and deacidified, it is introduced In the adsorption column of the hydrogenation resource absorption unit filler, the resourceful treatment of phosphine is realized, and the montmorillonite clay adsorbent that absorbs phosphine is directly transported to the landfill area and buried in the soil. In this process, the montmorillonite clay adsorbent is added to the subsequent adsorption column of the anaerobic reactor to absorb the generated phosphine, and then the co-reacted adsorbent is directly buried in the soil to avoid environmental pollution, thus completing Recycling treatment of phosphine to achieve standard removal of phosphorus from sewage sludge, rapid production and resource utilization of phosphine.

Description

A coupled phosphorus removal process for sewage sludge treatment

technical field

The invention relates to a sewage purification treatment method, in particular to a phosphorus removal coupled phosphorus process for sewage sludge treatment.

Background technique

Eutrophication of water body is one of the main environmental problems at present, which seriously restricts the sustainable development of society and economy. Phosphorus, as a nutrient factor, is one of the important factors that induce eutrophication in water bodies. The phosphorus in water mainly comes from domestic sewage, detergents and industrial wastewater. How to effectively remove phosphorus in wastewater has always been a hot topic for environmental engineering researchers all over the world. Domestic and foreign researchers have done a lot of research on phosphorus removal theory, technology and related processes. However, most of them remove nitrogen, phosphorus and other pollutants in sewage at the cost of consuming a large amount of resources and energy, which has the disadvantage of "using energy consumption and energy" to transfer pollution. Therefore, it has become the focus of attention of the scientific community to break the traditional sewage phosphorus removal process and realize the resource utilization of phosphorus in sewage.

In recent years, the recovery of struvite has become a research hotspot. Phosphorus removal technology recovered in the form of struvite can be used to treat high-concentration ammonia nitrogen wastewater and high-concentration phosphate wastewater, as well as wastewater containing high-concentration ammonia nitrogen and phosphate at the same time, and can also reduce the generation of some nitrogen oxide types of atmospheric greenhouse gases in wastewater . However, these studies mainly focus on the recovery and treatment of chemical methods. Chemical phosphorus removal is not only expensive in chemicals and high in operating costs, but also leaves a large amount of anions in the water, which increases the salinity of the water and causes secondary pollution. At the same time, the nitrogen in the water , phosphorus content have not yet reached the discharge standards, but also need to be used for further treatment.

The process of biological phosphorus removal coupled with phosphorus resource recovery is an economical and reasonable technical route, and this technology is gradually becoming possible. Phosphorus in sewage may be the precursor of phosphine, which is reduced to phosphine under the action of anaerobic microorganisms, which exists in the form of free state and matrix-bound phosphine (matrix-bound). A survey of phosphorus in the anaerobic treatment of wastewater found that the maximum loss of total phosphorus was 78%. These findings provide ideas for wastewater phosphorus removal and phosphorus recovery cycle process. It not only shows that phosphorus can be removed in gaseous form in the process of wastewater phosphorus removal, but also shows that phosphorus can be recycled in gaseous form in the recycling process. Therefore, the discovery of phosphine in the process of sewage treatment immediately aroused widespread concern.

Therefore, it is necessary to study how the phosphorus in the anaerobic reactor system for phosphorus removal in sewage and its process is converted into phosphine, and how to stabilize the resource utilization of phosphine in the end, and then reveal the conversion process and removal mechanism of phosphorus in wastewater, and establish a resource regeneration system. Process technology is of great significance to broaden the application range of wastewater phosphorus removal biotechnology and change the traditional "energy consumption" technology.

Invention content

The object of the present invention is to address the deficiencies of the prior art, to provide a phosphorus removal coupled phosphorus process for sewage sludge treatment, in the process of sewage sludge phosphorus removal, phosphorus is removed in the form of phosphine, and resource recycling is carried out to Reduce the cost of sewage phosphorus treatment and improve the overall technical level of sewage phosphorus treatment.

The phosphorus removal coupled phosphorus process for sewage sludge treatment of the present invention is to convert the phosphorus in the sewage sludge into the form of phosphine, and then absorb the phosphine to make it a resource. The mud is discharged outside, and it is characterized in that the process includes the following operating procedures:

(1) Anaerobic process of sewage sludge

①Add sewage sludge into the vertical anaerobic baffle reactor, and add buffer agent sodium bicarbonate to adjust the pH value of the sewage sludge between 6 and 6.5, and add an appropriate amount of glucose with a concentration of 500mg/L as reducing sugar ;

②The vertical anaerobic baffle reactor is placed in a light-proof box in a completely dark environment, and the temperature in the reactor is kept at 32±1°C;

③Introduce nitrogen gas into the gas inlet at the bottom of the vertical anaerobic baffle reactor to start aeration, the gas flow rate is 0.08~0.09 m ³ /h (preferably 0.08 m ³ /h), so that the concentration of dissolved oxygen in the reactor is low 1mg/L; motor-controlled stirring blades are installed in the vertical anaerobic baffle reactor to fully stir the sewage sludge during the aeration process, and the stirring intensity is 50~60r/min (preferably 50r/min) ;

④ After the above-mentioned anaerobic reaction is complete, the generated phosphine gas is exported from the gas outlet on the upper part of the vertical anaerobic baffle reactor, dried by a drier to remove water, and then passed through two series-connected porous carriers for hydrogen oxidation. The U-shaped tube of sodium particles removes CO ₂ , and after being thoroughly dried by another dryer, the gas is introduced into the adsorption column equipped with the packing of the phosphine recycling absorption unit to realize the recycling treatment of phosphine. The hydrogen resource absorption unit filler is montmorillonite clay adsorbent;

(2) Anaerobic process of sewage sludge

The internal and external environmental conditions of the vertical anaerobic baffle reactor in this process are the same as those in the process (1), and the pH value and glucose concentration are also the same as those in the process (1);

①Turn off the nitrogen source in process (1), and continue to feed air into the reactor in process (1) to start aeration. The gas flow rate is 0.08 ~0.09m ³ /h, so that the dissolved oxygen in the reactor The concentration is 3mg/L higher, and the stirring blades fully stir the sewage sludge during the aeration process, and the stirring intensity is 50~60 r/min;

② After the aerobic reaction is complete, the generated phosphine gas is exported from the gas outlet on the upper part of the reactor. After drying, removing CO ₂ and drying again, the gas is introduced into the adsorption column equipped with the packing of the phosphine resource absorption unit In order to realize the recycling treatment of phosphine, the phosphine recycling absorption unit filler is montmorillonite clay adsorbent;

(3) The montmorillonite clay adsorbent that adsorbs phosphine is directly transported to the landfill area and buried in the soil.

Further, ② in step (2) is specifically: After the above-mentioned aerobic reaction is completely complete, the generated phosphine gas is exported from the gas outlet on the upper part of the reactor, dried by a drier to remove water, and passed through two series-connected The U-shaped tube equipped with porous carrier and sodium hydroxide particles is used to remove CO ₂ , and the sodium hydroxide particles are attached to the surface of the porous carrier; after being completely dried by another dryer, the gas is introduced into the phosphine resource Recycling treatment of phosphine is realized in the adsorption column of the packing of the absorption unit, and the packing of the absorbing unit for recycling of phosphine is montmorillonite clay adsorbent; the porous carrier can be a porous ceramic carrier or other polymer porous carrier.

Further, the pH value of the sewage sludge is adjusted to 6 in the steps (1) and (2) of the phosphorus removal coupled phosphorus process of the sewage sludge treatment.

Further, the temperature in the reactor in the steps (1) and (2) of the coupled phosphorus removal process for sewage sludge treatment is 32°C.

Further, the nitrogen source and the air source of the aeration in the phosphorus removal coupled phosphorus process of sewage sludge treatment are connected to the air inlet at the bottom of the reactor through a tee.

In the phosphorus removal coupled phosphorus process of sewage sludge treatment, in the anaerobic stage, phosphine has a tendency to accumulate; in the aerobic stage, the detection value of phosphine drops rapidly, but there is still a relatively stable level in the aerobic stage. Low levels of phosphine detected.

The production of phosphine is a complicated process for microorganisms. First, it is necessary to ensure that the reaction process is carried out in the dark, and second, a certain reducing power must be ensured in the reaction environment, that is, sufficient reducing sugar must be ensured.

The results showed that acidic conditions would promote the release of sludge-bound phosphine. With the increase of acidification degree, the disappearance rate of bound phosphine in anaerobic sludge was accelerated. When the concentration of phosphine decreases to a certain extent, the disappearance rate also decreases accordingly. Stirring will promote the release of phosphine, and the concentration of phosphine released under static conditions is about 1/2 of the former. The same temperature is also one of the factors affecting the formation of phosphine.

Compared with the prior art, the beneficial effect of the present invention is: add the montmorillonite clay adsorbent in the subsequent adsorption column of the anaerobic reactor, absorb the generated phosphine, and then directly bury the co-reacted adsorbent Into the soil, to avoid pollution to the environment, so as to complete the resource treatment of phosphine, to achieve the standard removal of phosphorus in sewage sludge, rapid production and resource utilization of phosphine.

Detailed ways

The technical solutions of the present invention will be further described below through specific examples. The following examples are not intended to limit the present invention.

Example 1

(1) Anaerobic process of sewage sludge

① Add sewage sludge to the vertical anaerobic baffle reactor, and add buffer agent sodium bicarbonate to adjust the pH value of the sewage sludge at 6, and add an appropriate amount of glucose with a concentration of 500mg/L as reducing sugar;

②The vertical anaerobic baffle reactor is placed in a light-proof box in a completely dark environment, and the temperature in the reactor is kept at 32°C;

③Introduce nitrogen into the gas inlet at the bottom of the vertical anaerobic baffle reactor to start aeration, the gas flow rate is 0.08 m ³ /h, so that the concentration of dissolved oxygen in the reactor is lower than 1mg/L; The plate reactor is equipped with motor-controlled stirring blades to fully stir the sewage sludge during the aeration process, and the stirring intensity is 50 r/min;

④ After the above-mentioned anaerobic reaction is complete, the generated phosphine gas is exported from the gas outlet on the upper part of the vertical anaerobic baffle reactor, dried by a drier to remove water, and then passed through two series-connected porous carriers for hydrogen oxidation. The U-shaped tube of sodium particles removes CO ₂ , and after being thoroughly dried by another dryer, the gas is introduced into the adsorption column equipped with the packing of the phosphine recycling absorption unit to realize the recycling treatment of phosphine. The hydrogen resource absorption unit filler is montmorillonite clay adsorbent;

(2) Anaerobic process of sewage sludge

The internal and external environmental conditions of the vertical anaerobic baffle reactor in this process are the same as those in the process (1), and the pH value and glucose concentration are also the same as those in the process (1);

①Turn off the nitrogen source in process (1), and continue to feed air into the reactor in process (1) to start aeration. The gas flow rate is 0.08 m ³ /h, so that the concentration of dissolved oxygen in the reactor The height is 3mg/L, and the stirring blades fully stir the sewage sludge during the aeration process, and the stirring intensity is 50 r/min;

② After the above aerobic reaction is complete, the generated phosphine gas is exported from the gas outlet on the upper part of the reactor, dried and dehydrated by a dryer, and passed through two series-connected U-shaped dehumidifiers equipped with porous carriers and sodium hydroxide particles. CO ₂ is removed through the tube, and the sodium hydroxide particles are attached to the surface of the porous carrier; after being thoroughly dried by another dryer, the gas is introduced into the adsorption column equipped with the packing of the phosphine resource utilization absorption unit to realize the phosphine The recycling treatment of phosphine, the filler of the phosphine recycling absorption unit is montmorillonite clay adsorbent;

(3) The montmorillonite clay adsorbent that adsorbs phosphine is directly transported to the landfill area and buried in the soil.

The nitrogen source and the air source of the aeration are connected through the tee and the gas inlet at the bottom of the reactor.

Phosphine was determined by secondary cold trap enrichment-gas chromatography (GC/NPD), and the gas chromatograph was Agilent7890A. The total phosphorus in sewage sludge samples was determined by molybdenum antimony anti-spectrophotometry. The change of phosphine and total phosphorus content in sewage sludge with time in this process, the test results are shown in Table 1.

Table 1

Reaction time (h) 1 2 3 4 5 6 Total phosphorus (mg/L) 30 28 30 27 26 20 Phosphine (ng/L) 120 430 100 20 20 20

The test results show that in the anaerobic stage, the total phosphorus concentration is relatively stable, and the phosphine is accumulated. In the subsequent aerobic stage, the detected value of phosphine drops rapidly and remains stable for a period of time thereafter.

In the dephosphorization coupled phosphorus process of sewage sludge treatment of the present invention, through the optimal control of various aspects such as pH value, temperature, aeration flow rate and stirring conditions, the generation amount of phosphine is greatly improved in the anaerobic reaction stage , to achieve a good phosphorus removal effect, and further to maintain a certain amount of phosphine production in the aerobic reaction stage, to better achieve the phosphorus removal effect on sewage sludge.

Example 2

(1) Anaerobic process of sewage sludge

① Add sewage sludge to the vertical anaerobic baffle reactor, and add buffer agent sodium bicarbonate to adjust the pH value of the sewage sludge to 6.5, and add an appropriate amount of glucose with a concentration of 500mg/L as reducing sugar;

②The vertical anaerobic baffle reactor is placed in a light-proof box in a completely dark environment, and the temperature in the reactor is kept at 32°C;

③Introduce nitrogen gas into the gas inlet at the bottom of the vertical anaerobic baffle reactor to start aeration, the gas flow rate is 0.09m ³ /h, so that the concentration of dissolved oxygen in the reactor is lower than 1mg/L; The plate reactor is equipped with motor-controlled stirring blades to fully stir the sewage sludge during the aeration process, and the stirring intensity is 60 r/min;

④ After the above-mentioned anaerobic reaction is complete, the generated phosphine gas is exported from the gas outlet on the upper part of the vertical anaerobic baffle reactor, dried by a drier to remove water, and then passed through two series-connected porous carriers for hydrogen oxidation. The U-shaped tube of sodium particles removes CO ₂ , and after being thoroughly dried by another dryer, the gas is introduced into the adsorption column equipped with the packing of the phosphine recycling absorption unit to realize the recycling treatment of phosphine. The hydrogen resource absorption unit filler is montmorillonite clay adsorbent;

(2) Anaerobic process of sewage sludge

The internal and external environmental conditions of the vertical anaerobic baffle reactor in this process are the same as those in the process (1), and the pH value and glucose concentration are also the same as those in the process (1);

①Turn off the nitrogen source in process (1), and continue to feed air into the reactor in process (1) to start aeration. The gas flow rate is 0.09 m ³ /h, so that the concentration of dissolved oxygen in the reactor The height is 3mg/L, and the stirring blades fully stir the sewage sludge during the aeration process, and the stirring intensity is 60 r/min;

② After the above aerobic reaction is complete, the generated phosphine gas is exported from the gas outlet on the upper part of the reactor, dried and dehydrated by a dryer, and passed through two series-connected U-shaped dehumidifiers equipped with porous carriers and sodium hydroxide particles. CO ₂ is removed through the tube, and the sodium hydroxide particles are attached to the surface of the porous carrier; after being thoroughly dried by another dryer, the gas is introduced into the adsorption column equipped with the packing of the phosphine resource utilization absorption unit to realize the phosphine The recycling treatment of phosphine, the filler of the phosphine recycling absorption unit is montmorillonite clay adsorbent;

(3) The montmorillonite clay adsorbent that adsorbs phosphine is directly transported to the landfill area and buried in the soil.

The nitrogen source and the air source of the aeration are connected through the tee and the gas inlet at the bottom of the reactor.

Phosphine was determined by secondary cold trap enrichment-gas chromatography (GC/NPD), and the gas chromatograph was Agilent7890A. The total phosphorus in sewage sludge samples was determined by molybdenum antimony anti-spectrophotometry. The change of phosphine and total phosphorus content in sewage sludge with time in this process, the test results are shown in Table 2.

Table 2

Reaction time (h) 1 2 3 4 5 6 Total phosphorus (mg/L) 31 29 30 27 26 20 Phosphine (ng/L) 125 425 100 20 20 20

The test results show that in the anaerobic stage, the total phosphorus concentration is relatively stable, and the phosphine is accumulated. In the subsequent aerobic stage, the detected value of phosphine drops rapidly and remains stable for a period of time thereafter.

In the dephosphorization coupled phosphorus process of sewage sludge treatment of the present invention, through the optimal control of various aspects such as pH value, temperature, aeration flow rate and stirring conditions, the generation amount of phosphine is greatly improved in the anaerobic reaction stage , to achieve a good phosphorus removal effect, and further to maintain a certain amount of phosphine production in the aerobic reaction stage, to better achieve the phosphorus removal effect on sewage sludge.

For those skilled in the art, under the inspiration of the concept of the present invention and specific embodiments, some deformations that can be directly derived or associated from the disclosure of the present invention and common sense, those of ordinary skill in the art will realize that other methods can also be used, Or the replacement of common known technologies in the prior art, as well as non-essential changes such as different combinations of features, etc., can also be applied, and can realize the functions and effects described in the present invention, and will not be described in detail one by one. All belong to the protection scope of the present invention.

Claims (6)

1. the dephosphorization coupling phosphorus technology handled of a sewage sludge is characterized in that may further comprise the steps:

(1) anaerobic technique of sewage sludge

1. in vertical anaerobic baffled reactor, adding sewage sludge, and adding pH value that the buffer reagent sodium hydrogencarbonate regulates sewage sludge between 6～6.5, the glucose that adds concentration and be 500 (mg/L) is as reducing sugar;

2. vertical anaerobic baffled reactor is in the lucifuge case, be in the environment of complete dark, and the temperature in the maintenance reactor drum is 32 ± 1 ℃;

3. feed nitrogen at the air intake place of vertical anaerobic baffled reactor bottom and begin aeration, gas flow is 0.08 ~ 0.09 m ³/ h makes the concentration of dissolved oxygen in the reactor drum be lower than 1mg/L; Be provided with the agitating vane of electric machine control in the vertical anaerobic baffled reactor, in aeration process, sewage sludge fully stirred, stirring intensity is 50 ~ 60r/min;

4. after treating that above-mentioned anaerobic reaction fully, the phosphine gas of generation is derived from the air outlet on vertical anaerobic baffled reactor top, through dry, removal CO ₂After the drying, the gas introducing is equipped with in the adsorption column of phosphuret-(t)ed hydrogen resource utilization absorptive unit filler, realizes the recycling treatment of phosphuret-(t)ed hydrogen, this phosphuret-(t)ed hydrogen resource utilization absorptive unit filler is the montmorillonitic clay sorbent material;

(2) anaerobic technique of sewage sludge

1. close the source nitrogen that feeds in the step (1), change that the continuation bubbling air begins aeration the vertical anaerobic baffled reactor in step (1) in into, gas flow is 0.08 ~ 0.09m ³/ h makes the concentration of dissolved oxygen in the reactor drum be higher than 3mg/L, and agitating vane fully stirs sewage sludge in aeration process, and stirring intensity is 50 ~ 60 r/min;

2. after treating that aerobic reaction completely, the phosphine gas of generation is derived from the air outlet on reactor drum top, through dry, removal CO ₂After the drying, the gas introducing is equipped with in the adsorption column of phosphuret-(t)ed hydrogen resource utilization absorptive unit filler, realizes the recycling treatment of phosphuret-(t)ed hydrogen, this phosphuret-(t)ed hydrogen resource utilization absorptive unit filler is the montmorillonitic clay sorbent material.

2. the dephosphorization coupling phosphorus technology that sewage sludge according to claim 2 is handled, it is characterized in that also comprising: the montmorillonitic clay sorbent material that will adsorb phosphuret-(t)ed hydrogen directly is transported to the landfill district and places into the soil.

3. the dephosphorization coupling phosphorus technology that sewage sludge according to claim 1 is handled is characterized in that described in step (1) and the step (2) through dry, removal CO ₂Drying specifically again: dewater through a moisture eliminator drying, remove CO through two placed in-line U type pipes that porous support, sodium hydrate particle are housed ₂, said sodium hydrate particle is attached on the porous support surface; Pass through another moisture eliminator finish-drying again.

4. the dephosphorization coupling phosphorus technology of handling according to the described sewage sludge of claim 1-3, the pH value that it is characterized in that all regulating in step (1) and (2) sewage sludge is 6.

5. the dephosphorization coupling phosphorus technology that sewage sludge according to claim 1 and 2 is handled is characterized in that all keeping the temperature in the reactor drum in step (1) and (2) is 32 ℃.

6. the dephosphorization coupling phosphorus technology that sewage sludge according to claim 1 is handled, the source nitrogen that it is characterized in that aeration and air source are that the air intake through threeway and reactor bottom links to each other.