CN106995238A - The method and immobilization bioreactor of ammonia nitrogen in a kind of processing waste water - Google Patents

Abstract

The invention belongs to the technical field of water pollution control, and in particular relates to a method for treating ammonia nitrogen in waste water and an immobilized bioreactor. In the method, the waste water is circulated between the anoxic zone and the aerobic zone and then flows into the sedimentation zone, and the denitrification effect is excellent. In the aerobic zone, the mixture of vinyl alcohol-sodium alginate embedded particles and activated sludge is used as the microbial degradation material. Not only large microbial load, low microbial inhibition effect, strong tolerance to shock load and toxic substances, fast nitrification rate, less sludge output, stable operation, but also relatively simple embedded particle reactor, greatly shortening the particle size. The domestication time can reach a low and stable effluent ammonia nitrogen concentration in a short period of time, and has the advantages of activated sludge adsorption and embedded particles to weaken the impact of high-concentration free ammonia on microbial activity. The synergistic effect of the two It enriches the community diversity, enhances the operation effect of the system, and has a good treatment effect on high-concentration ammonia nitrogen.

Description

A method for treating ammonia nitrogen in wastewater and immobilized bioreactor

technical field

The invention belongs to the technical field of water pollution control, and in particular relates to a method for treating ammonia nitrogen in waste water and an immobilized bioreactor.

technical background

Ammonia nitrogen in wastewater mainly comes from urban sewage and industrial wastewater. Among them, ammonia nitrogen in industrial wastewater is still one of the main contributors to the nitrogen load in the water environment due to its large concentration changes, high toxicity, high content of refractory organic matter, and difficult treatment. First, it has increasingly become the focus of ammonia nitrogen load control in the water environment. At present, the biological denitrification method widely used in the field of wastewater treatment is limited by unfavorable factors such as difficulty in the growth and proliferation of nitrifying bacteria, poor activity of nitrifying bacteria, and insufficient carbon source available to microorganisms. There are differences in the application of biological nitrification and denitrification to industrial ammonia nitrogen wastewater. degree of failure.

Therefore, seeking an efficient, economical, stable and controllable biological denitrification method for industrial ammonia nitrogen wastewater has always been a hot and difficult point in the research of industrial ammonia nitrogen wastewater treatment. Immobilized microbial technology has become a research hotspot in the treatment of industrial ammonia nitrogen wastewater due to its advantages of large microbial load, strong tolerance to impact load and toxic substances, fast nitrification rate, low sludge output, and stable operation. The treatment effect of immobilized microorganism technology is mainly related to two factors, one is filler, the filler currently used is mainly embedding particles of a single bacterial strain; the other is the reactor, the currently used immobilized bioreactor mainly includes stirring There are three types of trough type, fixed packed bed and fluidized bed. Among them, the stirred tank reactor is mostly operated in batches, which can make the microorganisms in the reactor evenly distributed and improve the utilization rate of microorganisms, but the shear force is too large, which is easy to cause The particles made by embedding immobilization method or cross-linking immobilization method are broken; the immobilized microorganisms in the fixed packed bed reactor will squeeze each other or even rupture due to excessive operating pressure, resulting in the reduction of microbial catalytic activity and gas-liquid - The large bubbles generated in the solid three-phase flow affect the operation effect; while the operation of the fluidized bed reactor is strict and the cost is too high.

Contents of the invention

One object of the present invention is to provide a method for treating ammonia nitrogen in wastewater, which has short domestication time, low microbial inhibition effect, fast nitrification speed, low sludge production, high ammonia nitrogen degradation efficiency, rich community diversity, and shock load resistance Strong, stable operation, can efficiently treat high ammonia nitrogen industrial wastewater.

Another object of the present invention is to provide a biological immobilization reactor for treating ammonia nitrogen in wastewater, which has low energy consumption, good three-phase mixing effect, high oxygen mass transfer coefficient, simple operation, and saves land occupation.

In order to realize the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A method for treating ammonia nitrogen in waste water, the waste water is circulated between the anoxic zone and the aerobic zone, then flows into the sedimentation zone, and is discharged after sedimentation in the sedimentation zone, characterized in that: the anoxic zone uses activated sludge as the microorganism Degradable material, the aerobic zone uses the mixture of vinyl alcohol-sodium alginate embedded particles and activated sludge as the microbial degradation material, the dissolved oxygen concentration in the anoxic zone does not exceed 0.2mg/L, and the dissolved oxygen concentration in the aerobic zone is 4-5mg/L, the total hydraulic retention time of wastewater in anoxic zone and aerobic zone is at least 4 hours.

The method according to the present invention is characterized in that: the activated sludge is nitrification sludge.

According to the method of the present invention, it is characterized in that: the vinyl alcohol-sodium alginate embedding particles are prepared from the following components, in every 100mL aqueous solution, 10-15g of polyvinyl alcohol, 0.1-1.0g of sodium alginate, Activated sludge 10-20g.

According to the method of the present invention, it is characterized in that: the vinyl alcohol-sodium alginate embedding particles are prepared from the following components, in every 100mL aqueous solution, 10g of polyvinyl alcohol, 0.8g of sodium alginate, and 10g of activated sludge .

According to the method of the present invention, it is characterized in that: the vinyl alcohol-sodium alginate embedding particles are prepared from the following components, in every 100mL aqueous solution, 10g of polyvinyl alcohol, 0.8g of sodium alginate, and 10g of activated sludge , the polyvinyl alcohol polymerization degree is 1700-1800.

According to the method of the present invention, it is characterized in that: the preparation of the vinyl alcohol-sodium alginate embedding particles comprises the following preparation steps:

(1) Preparation of polyvinyl alcohol-sodium alginate gel solution: add polyvinyl alcohol 10-15g, sodium alginate 0.1-1.0g, activated sludge 10-20g in every 100mL aqueous solution, and mix polyvinyl alcohol , sodium alginate, and deionized water are mixed and heated to form a gel, ultrasonicated, and left to stand for use;

(2) Mixing with activated sludge: After acclimating the activated sludge, centrifuging, and washing with normal saline, add it to the mixed gel solution obtained in step (1), and mix evenly;

(3) Preparation of embedding particles: drop the homogeneously mixed mixture in step (2) into a saturated boric acid solution containing 2% CaCl ₂ to prepare embedding particles with a particle size of 3-4 mm and a specific surface area of 4-10 m ² /g , and stir cross-linking on a constant temperature magnetic stirrer for 30min;

(4) Post-treatment: transfer the product obtained in step (3) to 0.5 mol/L Na ₂ SO ₄ solution, place it at 4°C for 2 hours, wash it with normal saline, and freeze and thaw it 4 times at -20°C, remove Wash with ion water, and store at 4°C in wastewater with an ammonia nitrogen concentration of 50mg/L until use;

Wherein, the ultrasonic frequency described in step (1) is 40kHz, and the ultrasonic time is 30min;

The standing time described in the step (1) is 4 hours;

The centrifugal speed described in the step (2) is 3000-5000r/min, and the centrifugal time is 10-20min; preferably, the centrifugal speed described in the step (2) is 3000r/min, and the centrifugal time is 15min ;

The number of washings with physiological saline in step (2) is 1-3 times.

According to the method of the present invention, it is characterized in that: the total hydraulic retention time of wastewater in anoxic zone and aerobic zone is 4-20 hours; preferably, the total hydraulic retention time of wastewater in anoxic zone and aerobic zone is 4-20 hours. 16 hours.

In a specific embodiment, when the wastewater ammonia nitrogen concentration is 100mg/L, the total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is 4h; when the wastewater ammonia nitrogen concentration is 400mg/L, the wastewater is in the anoxic zone and The total hydraulic retention time in the oxygen zone is 16h.

The method according to the present invention is characterized in that: the residence time ratio of the wastewater in the anoxic zone and the aerobic zone is 1:1.5-2.5.

According to the method of the present invention, it is characterized in that: the circulation velocity of the waste water in the anoxic zone and the aerobic zone is 0.06-0.1m/s.

The method according to the present invention is characterized in that: the hydraulic retention time of the wastewater in the sedimentation zone is 0.5-4 hours.

The method for treating ammonia nitrogen in wastewater provided by the invention has the following advantages:

(1) The wastewater is circulated in the anoxic zone and the aerobic zone, and after being fully denitrified in the anoxic zone filled with activated sludge, it enters the aerobic zone filled with activated sludge and vinyl alcohol-sodium alginate embedded particles Nitrification, denitrification effect is significantly improved;

(2) In the aerobic zone, the mixture of activated sludge and vinyl alcohol-sodium alginate embedded particles is used as the microbial degradation material, which not only has a large microbial load, but also has a strong tolerance to impact loads and toxic substances, and a fast nitrification rate. The sludge output is small, the operation is stable, and the relatively simple embedded particle reactor greatly shortens the acclimation time of the particles, and can achieve a low and stable effluent ammonia nitrogen concentration in a short period of time, and has both activated sludge Adsorption and embedding particles have the advantages of weakening the impact of high concentration of free ammonia on microbial activity. The synergistic effect of the two enriches the diversity of the community and enhances the operating effect of the system.

In a second aspect, the present invention provides an immobilized bioreactor for wastewater ammonia nitrogen treatment, including a nitrification/denitrification unit and a precipitation unit co-walled with the nitrification/denitrification unit, characterized in that:

The left middle part of the nitrification/denitrification unit is provided with a vertical partition wall to divide the nitrification/denitrification unit into an anoxic zone on the left and an aerobic zone on the right, and the upper part of the partition wall passes through the upper screen It is connected to the top of the nitrification/denitrification unit, and the lower part of the partition wall is connected to the bottom of the nitrification/denitrification unit through the lower screen. The upper screen and the lower screen can not only keep the embedded particles in the aerobic area, but also Without affecting the circulation and exchange of sewage between the anoxic zone and the aerobic zone, the bottom of the nitrification/denitrification unit is provided with a sludge discharge port connected to the sludge discharge pipe, which can realize the disposal of aged particles and excess sludge emission;

The upper part of the left wall of the anoxic zone is provided with a water inlet, and a stirring device is installed in the anoxic zone, so that the sewage can be lifted and circulated and mixed evenly;

The middle part of the right wall of the aerobic zone is provided with an underwater thruster to promote the circulation of sewage between the anoxic zone and the aerobic zone, and the bottom of the aerobic zone is provided with an aeration device for aerobic Zone oxygen supply, the upper right part of the aerobic zone is provided with a conduit passing through the right wall of the aerobic zone, the left opening end of the conduit is equipped with a filter to realize the separation of embedded particles and sewage;

The middle part of the settling unit is provided with a central pipe, the upper part of the central pipe communicates with the right open end of the conduit, the lower part extends into the lower part of the settling unit, the upper right wall of the settling unit is provided with a water outlet, and the settling unit The bottom of the tank is provided with a sludge discharge outlet connected to the sludge discharge pipe, which can realize the discharge of sludge.

Further, the upper part of the aerobic zone is provided with a deflector, and the deflector forms an angle of α ₁ with the vertical plane from the upper left to the lower right, and α ₁ is 52-54°; preferably, α ₁ is 53° °, which can promote the circulation of sewage between the anoxic zone and the aerobic zone.

Furthermore, the front of the conduit is provided with a baffle, which can realize the separation of embedded particles and sewage on the one hand, and allow sewage to flow into the conduit at a uniform speed on the other hand.

Further, the pore size of the upper sieve, the lower sieve and the filter is smaller than the particle size of the particles embedded in the aerobic zone; preferably, the pore size of the upper sieve, the lower sieve and the filter is less than 2.5 mm.

Further, the upper part of the nitrification/denitrification unit is a cuboid, and the lower part is a square bucket, and the angle between the inclined wall corresponding to the length of the square bucket and the horizontal plane is 45°.

Further, the geometric size of the nitrification/denitrification unit satisfies the following relationship: Q×t=( _Heffective -H ₁ )L ₁ ×L ₂ +[L ₁ ×L ₂ +L ₃ ×L ₄ +√(L ₁ ×L ₂ +L ₃ ×L ₄ )]×H ₁ /3, L ₂ =1.5L ₁ ,

_Heffective =3.7L ₁ , l ₁ =H－7/6H ₁ , h=1/2H ₁ , H ₁ =1/2L ₂ ×tan45°×(1-L ₄ /L ₂ ), l ₂ =2/ 5L ₂ , H=H ₂ +H _{is effective} , the length ratio of anoxic zone to aerobic zone is 1:2, where,

Q is the inflow of sewage,

t is the residence time,

L1 is the width of the cuboid above the nitrification/denitrification unit,

L2 is the length of the cuboid above the nitrification/denitrification unit,

L3 is the width of the bottom of the square bucket in the lower part of the nitrification/denitrification unit,

L4 is the length of the bottom of the square bucket in the lower part of the nitrification/denitrification unit,

H1 is the height of the lower square bucket of the nitrification/denitrification unit, and H is the _effective depth of the nitrification/denitrification unit,

H2 is the safe height,

H is the total height,

l ₁ is the height of the partition wall,

h is the distance from the partition wall to the bottom of the square bucket,

l ₂ is the length of the deflector.

Further, the upper part of the settling unit is a cuboid, and the lower part is a square bucket, and the inclined wall corresponding to the length of the square bucket forms an included angle of 60° with the horizontal plane.

Further, the geometric dimensions of the precipitation unit satisfy the following relationship: L ₅ =L ₁ , L ₅ =L ₆ , L ₈ =L ₉ , _H'effective = _Heffective =3.7L ₁ , wherein,

L5 is the width of the upper cuboid of the precipitation unit,

L6 is the length of the cuboid above the precipitation unit,

L8 is the width of the bottom of the square bucket at the lower part of the sedimentation unit,

L9 is the length of the bottom of the square bucket at the lower part of the sedimentation unit,

H'effective is the _effective depth of the precipitation unit.

The immobilized bioreactor provided by the present invention is provided with anoxic zone and aerobic zone, and when the circulation and exchange of waste water and activated sludge are realized in the anoxic zone and aerobic zone through the upper screen and the lower screen, the The embedded particles remain in the aerobic zone, which greatly improves the effect of nitrification/denitrification, and the denitrification effect of wastewater is significantly improved; in addition, the immobilized bioreactor provided by the present invention adopts the integrated design of anoxic, aerobic and sedimentation, including The buried particles are directly added in the upper part of the aerobic zone, the sludge is discharged through the lower sludge discharge pipe, and the sewage is discharged directly after passing through the sedimentation zone, which is convenient, simple and easy to operate, and saves land occupation.

Description of drawings

Fig. 1 is the three-dimensional structural diagram (ignoring the wall thickness) of the immobilized bioreactor of the present invention;

Fig. 2 is the sectional view of immobilized bioreactor of the present invention;

Fig. 3 is the left view of the nitrification and denitrification unit of the immobilized bioreactor of the present invention;

Fig. 4 is a left view showing the structure of the sedimentation unit of the immobilized bioreactor of the present invention;

In the figure,

1-nitrification/denitrification unit, 11-partition wall, 12-anoxic zone, 121-water inlet, 122-stirring device, 13-aerobic zone, 131-underwater flow device, 132-aeration device, 133 - conduit, 134 - filter screen, 135 - deflector, 136 - baffle, 14 - upper screen, 15 - lower screen, 16 - sludge discharge port;

2-sedimentation unit, 21-center pipe, 22-water outlet, 23-sludge outlet;

3 - Mud discharge pipe.

detailed description

Preparation of embodiment 1 embedding particles

(1) Preparation of polyvinyl alcohol-sodium alginate gel solution: add polyvinyl alcohol 10g, sodium alginate 0.8g, activated sludge 10g in every 100mL aqueous solution, mix polyvinyl alcohol, sodium alginate, Ionized water was mixed and heated to form a gel, ultrasonically treated at an ultrasonic frequency of 40kHz for 30min, and left to stand for 4h for later use;

(2) Mixing with activated sludge: domesticate activated sludge, centrifuge at 3000r/min for 15min, wash with normal saline, add to the mixed gel solution obtained in step (1), and mix evenly;

(3) Preparation of embedding particles: drop the homogeneously mixed mixture in step (2) into a saturated boric acid solution containing 2% CaCl ₂ to prepare embedding particles with a particle size of 3-4 mm and a specific surface area of 4-10 m ² /g , and stir cross-linking on a constant temperature magnetic stirrer for 30min;

(4) Post-treatment: transfer the product obtained in step (3) to 0.5mol/L Na ₂ SO ₄ solution, place it at 4°C for 2 hours, wash it with normal saline for 1-3 times, and freeze and thaw repeatedly at -20°C 4 times, washed with deionized water, and stored at 4°C in wastewater with an ammonia nitrogen concentration of 50mg/L until use;

Implementation Case 2 Preparation of Embedded Particles

Preparation of polyvinyl alcohol-sodium alginate gel solution: 10 g of polyvinyl alcohol, 0.1 g of sodium alginate, and 15 g of activated sludge were added to every 100 mL of aqueous solution.

The preparation method is the same as in Example 1.

Implementation Case 3 Preparation of Embedded Particles

Preparation of polyvinyl alcohol-sodium alginate gel solution: 15 g of polyvinyl alcohol, 1.0 g of sodium alginate, and 20 g of activated sludge were added to every 100 mL of aqueous solution.

The preparation method is the same as in Example 1.

Implementation Case 4 Preparation of Embedded Particles

Preparation of polyvinyl alcohol-sodium alginate gel solution: 10 g of polyvinyl alcohol, 0.5 g of sodium alginate, and 15 g of activated sludge were added to every 100 mL of aqueous solution.

The preparation method is the same as in Example 1.

Example 5

Referring to the immobilized bioreactor shown in Figures 1-2, it includes a nitrification/denitrification unit 1 and a precipitation unit 2 co-walled with the nitrification/denitrification unit 1, and the left middle part of the nitrification/denitrification unit 1 is set There is a vertical partition wall 11 that divides the nitrification/denitrification unit 1 into an anoxic zone 12 on the left and an aerobic zone 13 on the right. 1, the bottom of the partition wall 11 is connected to the bottom of the nitrification/denitrification unit 1 through the lower screen 15, and the upper screen 14 and the lower screen 15 can realize that the embedded particles are retained in the aerobic zone 13, Without affecting the circulation and exchange of sewage between the anoxic zone 12 and the aerobic zone 13, the bottom of the nitrification/denitrification unit 1 is provided with a sludge discharge port 16 communicated with the sludge discharge pipe 3, which can realize aging Discharge of pellets and excess sludge;

The upper part of the left wall of the anoxic zone 12 is provided with a water inlet 121, and a stirring device 122 is installed in the anoxic zone 12, so that the sewage can be lifted and circulated and mixed evenly;

The middle part of the right wall of the aerobic zone 13 is provided with an underwater thruster 131 to promote the circulation of sewage between the anoxic zone and the aerobic zone, and the bottom of the aerobic zone 13 is provided with an aeration device 132 for use To supply oxygen to the aerobic zone, the upper right part of the aerobic zone 13 is provided with a conduit 133 passing through the right wall of the aerobic zone 13, and the left open end of the conduit 133 is equipped with a filter screen 134 to realize embedding particles and Separation of sewage;

The middle part of the sedimentation unit 2 is provided with a central pipe 21, the upper part of the central pipe 21 communicates with the right open end of the conduit 133, and the lower part extends into the lower part of the sedimentation unit 2, and the upper right wall of the sedimentation unit 2 is provided with a water outlet 22. The bottom of the sedimentation unit 2 is provided with a sludge discharge outlet 23 communicated with the sludge discharge pipe 3 to realize sludge discharge.

The top of the aerobic zone 13 is provided with a deflector 135, and the deflector 135 forms an angle of α ₁ with the vertical plane from the upper left to the lower right, and α ₁ is 52-54°; preferably, α ₁ is 53°, which can promote the circulation of sewage between the anoxic zone and the aerobic zone.

The front of the conduit 133 is provided with a baffle 136 , which can realize the separation of embedded particles and sewage on the one hand, and allow the sewage to flow into the conduit 133 at a constant speed on the other hand.

The apertures of the upper screen 14, the lower screen 15 and the filter screen 134 are smaller than the particle diameter of the embedded particles in the aerobic zone; preferably, the apertures of the upper screen 14, the lower screen 15 and the filter screen 134 are less than 2.5 mm.

The upper part of the nitrification/denitrification unit 1 is a cuboid, and the lower part is a square bucket. The angle between the inclined wall corresponding to the length of the square bucket and the horizontal plane is 45°.

The geometric dimensions of the nitrification/denitrification unit 1 satisfy the following relationship: Q×t=( _Heffective -H ₁ )L ₁ ×L ₂ +[L ₁ ×L ₂ +L ₃ ×L ₄ +√(L ₁ ×L ₂ +L ₃ ×L ₄ )]×H ₁ /3, L ₂ =1.5L ₁ , H _effective =3.7L ₁ , l ₁ =H-7/6H ₁ , h=1/2H ₁ , H ₁ =1/2L ₂ ×tan45°×(1-L ₄ /L ₂ ), l ₂ =2/5L ₂ , H=H _effective +H ₂ The anoxic zone 12 has the same width as the aerobic zone 13, and the anoxic zone 12 and the length ratio of the aerobic zone 13 is 1:2, wherein,

Q is the inflow of sewage,

t is the residence time,

L1 is the width of the upper cuboid of nitrification/denitrification unit 1,

L2 is the length of the upper cuboid of nitrification/denitrification unit 1,

L3 is the width of the bottom of the square bucket in the lower part of nitrification/denitrification unit 1,

L4 is the length of the bottom of the square bucket in the lower part of nitrification/denitrification unit 1,

H1 is the height of the lower square bucket of nitrification/denitrification unit 1,

H _effective is the effective depth of nitrification/denitrification unit 1,

H is the total height of the reactor,

H ₂ is the safe height.

l ₁ is the height of the partition wall 11,

h is the distance between the partition wall 11 and the bottom of the square bucket,

l ₂ is the length of the deflector.

The upper part of the settling unit 2 is a cuboid, and the lower part is a square bucket, and the inclined wall corresponding to the length of the square bucket forms an included angle of 60° with the horizontal plane.

The geometric dimensions of the precipitation unit 2 satisfy the following relationship: L ₅ =L ₁ , L ₅ =L ₆ , L ₈ =L ₉ , _H'effective = _Heffective =3.7L ₁ , wherein,

L5 is the width of the upper cuboid of precipitation unit 2,

L6 is the length of the upper cuboid of precipitation unit 2,

L8 is the width of the bottom of the square bucket at the bottom of the sedimentation unit 2,

L9 is the length of the bottom of the square bucket at the bottom of the sedimentation unit 2,

H' _effectively is the effective depth of the settling unit 2 .

The treatment of embodiment 6 ammonia nitrogen wastewater

The wastewater with an initial ammonia nitrogen concentration of 100 mg/L and a COD of about 500 mg/L is run in the immobilized bioreactor shown in Example 5, and the concentration of mixed liquid suspended solids (MLSS) in the anoxic zone is controlled at about 4000 mg/L In the aerobic zone, 10% of the volume of the aerobic zone is put into the embedding particles prepared in Example 2, the dissolved oxygen concentration in the anoxic zone is no more than 0.2mg/L, and the dissolved oxygen (DO) in the aerobic zone is controlled at about 4mg/L. Add Na ₂ CO ₃ to adjust the pH value to 7.5-8.5. The total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is 4 hours, and the ratio of the residence time in the anoxic zone to the aerobic zone is 1:1.5. The hydraulic retention time is 0.5h, the concentration of ammonia nitrogen in the water flowing out from the outlet of the sedimentation area is 3.69mg/L, and the removal rate of ammonia nitrogen is 96.31%.

The treatment of embodiment 7 ammonia nitrogen wastewater

The wastewater with an initial ammonia nitrogen concentration of 200 mg/L and a COD of about 500 mg/L is run in the immobilized bioreactor shown in Example 5, and the concentration of mixed liquid suspended solids (MLSS) in the anoxic zone is controlled at about 4000 mg/L In the aerobic zone, 10% of the volume of the aerobic zone is put into the embedded particles prepared in Example 3, the dissolved oxygen concentration in the anoxic zone is no more than 0.2 mg/L, and the dissolved oxygen (DO) in the aerobic zone is controlled at about 5 mg/L. Add Na ₂ CO ₃ to adjust the pH value to 7.5-8.5. The total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is 1.5 hours, and the ratio of the residence time in the anoxic zone to the aerobic zone is 1:2. The hydraulic retention time is 1h, the concentration of ammonia nitrogen in the water flowing out from the outlet of the sedimentation area is 26.42mg/L, and the removal rate of ammonia nitrogen is 86.79%.

The treatment of embodiment 8 ammonia nitrogen wastewater

The wastewater with an initial ammonia nitrogen concentration of 300 mg/L and a COD of about 500 mg/L is run in the immobilized bioreactor shown in Example 5, and the concentration of mixed liquid suspended solids (MLSS) in the anoxic zone is controlled at about 4000 mg/L In the aerobic zone, 10% of the volume of the aerobic zone is put into the embedded particles prepared in Example 1, the dissolved oxygen concentration in the anoxic zone is no more than 0.2 mg/L, and the dissolved oxygen (DO) in the aerobic zone is controlled at about 5 mg/L. Add Na ₂ CO ₃ to adjust the pH value to 7.5-8.5. The total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is 12 hours. The ratio of the residence time in the anoxic zone and the aerobic zone is 1:2. The hydraulic retention time is 3h, the concentration of ammonia nitrogen in the water flowing out from the outlet of the sedimentation area is 42.84mg/L, and the removal rate of ammonia nitrogen is 75.72%.

The treatment of embodiment 9 ammonia nitrogen wastewater

The wastewater with an initial ammonia nitrogen concentration of 400 mg/L and a COD of about 500 mg/L is run in the immobilized bioreactor shown in Example 5, and the concentration of mixed liquid suspended solids (MLSS) in the anoxic zone is controlled at about 4000 mg/L In the aerobic zone, 10% of the volume of the aerobic zone is put into the embedded particles prepared in Example 1, the dissolved oxygen concentration in the anoxic zone is no more than 0.2 mg/L, and the dissolved oxygen (DO) in the aerobic zone is controlled at about 5 mg/L. Add Na ₂ CO ₃ to adjust the pH value to 7.5-8.5. The total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is 16 hours. The ratio of the residence time in the anoxic zone and the aerobic zone is 1:2. The hydraulic retention time is 4h, the concentration of ammonia nitrogen in the water flowing out from the outlet of the sedimentation area is 136.96mg/L, and the removal rate of ammonia nitrogen is 65.76%.

Claims (10)

1. A method for treating ammonia nitrogen in waste water, the waste water is circulated between the anoxic zone and the aerobic zone and flows into the sedimentation zone, and is discharged after precipitation in the sedimentation zone, it is characterized in that: the described anoxic zone uses activated sludge It is a microbial degradation material. The aerobic zone uses a mixture of vinyl alcohol-sodium alginate embedded particles and activated sludge as the microbial degradation material. The dissolved oxygen concentration in the anoxic zone does not exceed 0.2mg/L, and the dissolved oxygen concentration in the aerobic zone The concentration is 4-5mg/L, and the total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is at least 4 hours. 2. The method according to claim 1, characterized in that: the activated sludge is nitrification sludge, and the vinyl alcohol-sodium alginate embedding particles are prepared from the following components, in every 100mL aqueous solution , polyvinyl alcohol 10-15g, sodium alginate 0.1-1.0g, activated sludge 10-20g; preferably, the vinyl alcohol-sodium alginate embedding particles are prepared from the following components, each 100mL aqueous solution , polyvinyl alcohol 10g, sodium alginate 0.8g, activated sludge 10g; further preferably, the vinyl alcohol-sodium alginate embedding particles are prepared from the following components, in every 100mL aqueous solution, polyvinyl alcohol 10g , sodium alginate 0.8g, activated sludge 10g, and the polyvinyl alcohol polymerization degree is 1700-1800. 3. method according to claim 1, is characterized in that: the total hydraulic retention time of waste water in anoxic zone and aerobic zone is 4-20 hour, and the residence time ratio in anoxic zone and aerobic zone is 1: 1.5-2.5, the circulation velocity in the anoxic zone and the aerobic zone is 0.06-0.1m/s; preferably, the total hydraulic retention time of the wastewater in the anoxic zone and the aerobic zone is 4-16 hours. 4. The method according to claim 1, characterized in that: the hydraulic retention time of the wastewater in the sedimentation zone is 0.5-4 hours. 5. An immobilized bioreactor for ammonia nitrogen treatment in wastewater, comprising a nitrification/denitrification unit (1) and a precipitation unit (2) co-walled with the nitrification/denitrification unit (1), characterized in that: The left middle part of the nitrification/denitrification unit (1) is provided with a vertical partition wall (11) to divide the nitrification/denitrification unit (1) into an anoxic zone (12) on the left and an aerobic zone on the right. Zone (13), the upper part of the partition wall (11) is connected to the top of the nitrification/denitrification unit (1) through the upper screen (14), and the lower part of the partition wall (11) is connected through the lower screen (15) Connected to the bottom of the nitrification/denitrification unit (1), the bottom of the nitrification/denitrification unit (1) is provided with a sludge discharge port (16) communicated with the sludge discharge pipe (3); A water inlet (121) is provided on the upper left wall of the anoxic zone (12), and a stirring device (122) is installed in the anoxic zone (12); The middle part of the right wall of the aerobic zone (13) is provided with an underwater thruster (131), and the bottom of the aerobic zone (13) is provided with an aeration device (132), and the aerobic zone (13) The upper right part is provided with a conduit (133) that passes through the right wall of the aerobic zone (13), and the left open end of the conduit (133) is equipped with a filter screen (134); The middle part of the settling unit (2) is provided with a central pipe (21), the upper part of the central pipe (21) communicates with the right open end of the conduit (133), and the lower part extends into the lower part of the settling unit (2). The upper part of the right wall of the sedimentation unit (2) is provided with a water outlet (22), and the bottom of the sedimentation unit (2) is provided with a mud discharge outlet (23) communicated with the mud discharge pipe (3). 6. The immobilized bioreactor according to claim 5, characterized in that: the upper part of the aerobic zone (13) is provided with a deflector (135), and the deflector (135) is from upper left to right Form an angle α ₁ with the vertical plane, α ₁ is 52-54 °; preferably, α ₁ is 53 °. 7. The immobilized bioreactor according to claim 5, characterized in that: a baffle (136) is provided in front of the conduit (133). 8. The immobilized bioreactor according to claim 5, characterized in that: the aperture of the upper screen (14), the lower screen (15) and the filter (134) is smaller than that of the particles embedded in the aerobic zone. Particle size; preferably, the apertures of the upper screen (14), lower screen (15) and filter (134) are less than 2.5mm. 9. The immobilized bioreactor according to claim 5, characterized in that: the upper part of the nitrification/denitrification unit (1) is a cuboid, the lower part is a square bucket, and the length of the square bucket corresponds to the inclined wall The included angle with the horizontal plane is 45°, and the geometric dimensions of the nitrification/denitrification unit (1) satisfy the following relationship: Q×t=( _Heffective -H ₁ )L ₁ ×L ₂ +[L ₁ ×L ₂ +L ₃ ×L ₄ +√(L ₁ ×L ₂ +L ₃ ×L ₄ )]×H ₁ /3, L ₂ ＝1.5L ₁ , H _{is effective} ＝3.7L ₁ , l ₁ ＝H－7/6H ₁ , h =1/2H ₁ , H ₁ =1/2L ₂ ×tan45°×(1-L ₄ /L ₂ ), l ₂ =2/5L ₂ , H=H ₂ +H _{is effective} , anoxic zone (12) and The length ratio of the aerobic zone (13) is 1:2, wherein, Q is the inflow of sewage, t is the residence time, L1 is the width of the upper cuboid of the nitrification/denitrification unit (1), L2 is the length of the upper cuboid of the nitrification/denitrification unit (1), L3 is the width of the bottom of the square bucket at the bottom of the nitrification/denitrification unit (1), L4 is the length of the bottom of the square bucket in the lower part of the nitrification/denitrification unit (1), H1 is the height of the lower square bucket of the nitrification/denitrification unit (1), H _effectively is the effective depth of the nitrification/denitrification unit (1), H2 is the safe height, H is the total height, l ₁ is the height of the partition wall (11), h is the distance between the partition wall (11) and the bottom of the square bucket, l ₂ is the length of the deflector. 10. The immobilized bioreactor according to claim 5, characterized in that: the upper part of the settling unit (2) is a cuboid, the lower part is a square bucket, and the inclined wall corresponding to the length of the square bucket is 60° from the horizontal plane. ° included angle, The geometric dimensions of the precipitation unit (2) satisfy the following relationship: L ₅ =L ₁ , L ₅ =L ₆ , L ₈ =L ₉ , _H'effective = _Heffective =3.7L ₁ , wherein, L5 is the width of the upper cuboid of the precipitation unit (2), L6 is the length of the upper cuboid of the precipitation unit (2), L8 is the width of the bottom of the square bucket at the bottom of the settling unit (2), L9 is the length of the bottom of the square bucket at the bottom of the settling unit (2), H'effective is the _effective depth of the precipitation unit (2).