CN112250172A

CN112250172A - Starting method of low-matrix-concentration anaerobic ammonia oxidation biofilm reactor

Info

Publication number: CN112250172A
Application number: CN202011121815.7A
Authority: CN
Inventors: 王少坡; 朱雅新; 于静洁; 王栋; 王晨晨; 刘楠楠; 李亚静; 邱春生
Original assignee: Tianjin Chengjian University
Current assignee: Tianjin Chengjian University
Priority date: 2020-10-20
Filing date: 2020-10-20
Publication date: 2021-01-22

Abstract

The invention discloses a starting method of a low-matrix-concentration SBR anaerobic ammonia oxidation biofilm reactor. The starting-up method of the reactor comprises the following steps: (1) pumping simulated wastewater without a carbon source into the reactor by a peristaltic pump; (2) before starting, adding return sludge of a secondary sedimentation tank into the reactor, and adding a small amount of anaerobic ammonia oxidation seed sludge in an activity lag phase; (3) adding polyethylene filler into the reactor in the middle of operation; (4) the reactor is started by adopting a mode of feeding water with low substrate concentration and gradually increasing nitrogen load; (5) treating simulated wastewater, wherein the treatment comprises the following stages: the water inlet, the anaerobic treatment, the sedimentation, the water outlet and the idle stage are circularly carried out. The invention has the advantages that the low-matrix-concentration water inlet mode is adopted, and the concentration inhibition of FA and FNA can be effectively avoided. And in the starting stage, the nitrogen load is gradually increased, and the domestication and enrichment of the anaerobic ammonium oxidation bacteria are accelerated. The addition of the filler effectively solves the problem that anaerobic ammonium oxidation bacteria are difficult to enrich.

Description

Starting method of low-matrix-concentration anaerobic ammonia oxidation biofilm reactor

Technical Field

The invention belongs to the technical field of biological sewage treatment, and particularly relates to a starting method of an SBR (sequencing batch reactor) anaerobic ammonia oxidation biofilm reactor in a mode of feeding water with low matrix concentration and gradually increasing nitrogen load. Is particularly suitable for treating domestic sewage in sewage treatment plants.

Background

Human beings discharge a large amount of nitrogen-containing waste water into the water body, cause the environmental pollution problems such as water eutrophication, etc., and nitrogen pollution has become one of the environmental problems in China and seriously harms human health. Typical nitrogen treatment processes include nitrification and denitrification, both of which are generally energy consuming and require large amounts of added carbon sources, increasing operating costs. However, anammox is a "shortcut".

ANAMMOX (ANAMMOX) is an autotrophic denitrification process, and the discovery of the ANAMMOX process provides a relatively economical and practical method for the treatment of low C/N ratio wastewater. The anammox bacteria exist widely in nature, but the content and abundance of the anammox bacteria are low, so that the anaerobic ammonia oxidation reactor is required to be inoculated with aerobic sludge or trace anammox sludge for acclimatization and culture. In addition, anaerobic ammonium oxidation bacteria (ANAOB) have long multiplication time, low specific proliferation rate and easy loss in the enrichment culture process. In addition, anammox bacteria are susceptible to influent substrate concentrations. So that the start-up of the anammox reactor can be a slow and difficult process. This limits the application of the anammox process. Therefore, the application of the anaerobic ammonia oxidation process can be effectively promoted by developing the starting method of the anaerobic ammonia oxidation process.

The SBR reactor has strong capability of retaining microorganisms, can effectively reduce sludge loss, and is beneficial to the growth of microorganisms with long generation cycle such as AnAOB. The addition of the filler in the reactor is beneficial to forming a microenvironment, is more beneficial to enrichment and culture of strains and enhances the hydraulic shock resistance. In addition, in the process of starting the reactor, the mode of introducing water with low matrix concentration and gradually increasing nitrogen load is adopted, so that the concentration inhibition of FA and FNA can be effectively avoided, and a foundation is laid for the efficient operation of the reactor.

Disclosure of Invention

The invention provides a method for starting an SBR anaerobic ammonia oxidation biomembrane reactor in a mode of feeding water with low matrix concentration and gradually increasing nitrogen load, aiming at solving the problems that AnAOB is difficult to enrich and the starting time of the anaerobic ammonia oxidation reactor is long.

In order to achieve the purpose, the technical scheme adopted by the invention is to provide a starting method of the SBR anaerobic ammonia oxidation biofilm reactor in a mode of feeding water with low matrix concentration and gradually increasing nitrogen load, the method adopts a method of feeding water with low matrix concentration and gradually increasing nitrogen load to start the reactor, filler is added into the reactor to enrich anaerobic ammonia oxidation bacteria, and the anaerobic ammonia oxidation sludge is domesticated by increasing nitrogen load in the starting process, and the method specifically comprises the following steps:

(1) the return sludge of the secondary sedimentation tank (MLSS is 4500mg/L) is inoculated before the SBR reactor is started, and the inoculation amount accounts for about 60 percent of the volume of the reactor. The test water is simulated sewage without adding organic carbon source, and the water inlet substrate is composed of NH₄HCO₃And NaNO₂The other components in the simulated wastewater are as follows: KH (Perkin Elmer)₂PO₄ 30mg/L、CaCl₂·2H₂O 36mg/L、NaHCO₃350mg/L and trace elements. And controlling the pH value to be 7.5-8.5 and the temperature to be 30 +/-2 ℃.

(2) The SBR reactor operates for three periods every day in the first four stages of starting, the duration of one period is 12 hours, the three periods comprise water feeding for 20 minutes, stirring for 6 hours, standing for 80 minutes and water discharging for 20 minutes, the water discharging ratio is set to be 33.3 percent, the HRT is set to be 24 hours, and sludge is not actively discharged in the operation process of the SBR reactor. In the last stage, when the reactor is unstable, the period of 8h is adjusted to 12h, namely 6h stirring is improved to 10h continuous stirring, and after the activity is recovered, the period is adjusted to 8h again.

(3) The start-up of the reactor, 156d, is carried out in a total of four stages: a thallus autolysis stage (1-22 d), an activity retardation stage (23-83 d), an activity improvement stage (84-124 d), an activity stabilization stage (125-156 d) and a reactor instability recovery stage (156-208 d). Wherein, when the operation lasts for 15d (autolysis stage), the sludge is stored in a constant temperature refrigerator at 4 ℃ for 28d, and the activity of the sludge is kept.

(4) And adding filler into the SBR reactor at the activity delay stage to enrich the AnAOB. The outside of the reactor is shielded by shading cloth, so that the reactor is strictly shaded;

according to the invention, the selected filler is High Density Polyethylene (HDPE) with a Density of 30%, the filler is a hollow cross-shaped framework, the internal space of the filler is divided into four chambers, the diameter of the four chambers is 10mm multiplied by 10mm, and the specific gravity of the filler is more than or equal to 0.95g/cm³The specific surface area is more than or equal to 500m²/m³。

(7) In the activity improvement stage, a small amount of anaerobic ammonium oxidation seed sludge is added into the reactor;

according to the invention, the volume of the SBR reactor is 14L, and the amount of the anammox sludge added is about 1/50 of the volume of the reactor.

(3) Starting the SBR anaerobic ammonia oxidation reactor, and domesticating anaerobic ammonia oxidation sludge by adopting a mode of feeding water with low substrate concentration and gradually increasing nitrogen load.

According to the invention, the nitrogen load is adjusted by adjusting the influent substrate concentration or the hydraulic retention time. Control of feed water NH at start-up₄ ⁺-N and NO₂ ^-The concentration of-N is about 50mg/L and 66mg/L respectively. The thalli autolysis stage is to feed water NH₄ ⁺Increase of-N to 60mg/L, NO₂ ^-the-N is increased to 79.2mg/L, and the effluent quality is not improved. Two consecutive increases of feed water NH in the activity-increasing stage₄ ⁺-N、NO₂ ^-The concentration of-N was 80mg/L and 105.6 mg/L. In the activity stabilization stage, NH is controlled by feeding water₄ ⁺-N and NO₂ ^-The concentration of-N is 70mg/L and 92.4mg/L respectively, and NH can be generated₄ ⁺The average removal rate of-N is more than 80%, and the average TRE is more than 63%. Subsequently, in order to ensure the supply of the substrate and to further increase the concentration of the substrate in the reactor, water NH is fed in₄ ⁺Increase of-N to 90mg/L, NO in feed water₂ ^-The increase in N to 118.8mg/L, no change in the cycle run time, and deterioration in the reactor performance occurred. Then the inlet water N isH₄ ⁺-N and NO₂ ^-N is respectively reduced to 70mg/L and 92.4mg/L, the hydraulic retention time is prolonged, the original 8h operation period is adjusted to 12h, and the treatment effect of the reactor is improved. The running period is then readjusted to a period of 8 h. NH at reaction run 206d₄ ⁺The removal rate of-N is increased to 85.0 percent, and the effluent NO is₂ ^-N is almost zero, and the total nitrogen removal rate is as high as 73.4 percent.

(7) Controlling NH in the early stage of SBR reactor₄ ⁺-N and NO₂ ^-The concentration ratio of-N is configured according to 1: 1.32, the concentration of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in inlet and outlet water is detected in the later period of operation, and the concentration of a substrate in the inlet water is adjusted according to the concentration of the ammonia nitrogen and nitrite nitrogen in the outlet water.

After the performance of the anaerobic ammonia oxidation reactor is stable, NH in the simulated wastewater can be ensured₄ ⁺The removal rate of-N is as high as 85 percent, and the effluent NO₂ ^-The N content is almost zero, and the total nitrogen removal rate is more than 60 percent on average. The sludge enters a stabilization phase.

The method of the present invention is not particularly limited, and may be selected according to the ordinary techniques in the art.

The beneficial effects of the invention are shown in the following aspects: (1) the inoculation of the anammox seed sludge accelerates the rapid start-up of the anammox reactor. (2) The addition of the filler effectively solves the technical problems that the sludge is easy to lose and difficult to enrich. (3) Adopts a low-substrate-concentration water inlet mode, can effectively avoid NH₄ ⁺-N and NO₂ ^--concentration inhibition of N. (4) And in the starting stage, the nitrogen load is gradually increased, and the domestication and enrichment of the anaerobic ammonium oxidation bacteria are accelerated. (5) The stirring device in the reaction stage mixes muddy water and raw water to ensure that the AnAOB is fully contacted with the matrix.

Drawings

Fig. 1 is a diagram showing an apparatus of an anaerobic ammonia oxidation biofilm reactor according to an embodiment of the present invention.

Wherein: 1. a water inlet pump; 2. an electric stirrer; 3. a stirring paddle; 4. a heating rod; a water outlet; 6. sampling port

Detailed Description

The starting method of the SBR anaerobic ammonia oxidation biofilm reactor in the mode of low substrate concentration water inlet and gradually increased nitrogen load is further explained by combining the concrete examples

The examples are not described in detail and are in accordance with the prior art in the field.

Examples

The starting method of the SBR anaerobic ammonia oxidation biofilm reactor comprises the following specific steps:

(1) reactor device

The SBR reactor is adopted in the test, the effective volume of the main body of the SBR reactor is a cylindrical organic glass container of 14L, the height of the SBR reactor is 600mm, the diameter of the cylindrical SBR reactor is 200mm, and a row of sampling ports with the spacing of 100mm are arranged in the vertical direction on the wall of the SBR reactor and used for sampling and draining. The reactor is supplemented with a time control switch, a constant temperature heating rod, an electromagnetic valve, a peristaltic pump, an electric stirrer and the like. The upper part of the reactor is a filler gathering area, the upper part of the reactor is filled with water, and the middle part of the reactor is drained.

(2) Inoculated sludge and filler

The experimental inoculation sludge is taken from return sludge of a secondary sedimentation tank of a certain Tianjin sewage treatment plant, MLSS is 4500mg/L, and the inoculation amount is about 60% of the effective volume of the reactor. The start-up phase was inoculated with a small amount of anammox sludge, about 1/50 in terms of the effective volume of the reactor.

The reactor is filled with High Density Polyethylene (HDPE) filler with diameter of 10 × 10mm and specific gravity of 0.95g/cm³Above, the specific surface area is more than 500m²/m³The filling ratio of the inoculation filler is about 30 percent.

(3) Composition and concentration of culture medium

The test water adopts artificial simulated wastewater, and the water inlet substrate is composed of NH₄HCO₃And NaNO₂The concentrations of the two are adjusted according to the operation effect, and no organic carbon source is added. The rest components and trace elements of the influent are shown in tables 1 and 2.

TABLE 1 simulation of wastewater quality

TABLE 2 microelement table

Mircronutrients：(1mL/L)

(4) Design of operating parameters

The temperature in the reactor is controlled to be 30 +/-2 ℃ through a heating rod, the pH is controlled to be 7.5-8.5, and the reactor is strictly protected from light. The test is carried out by adopting a mode of intermittent water inlet and outlet, and the reactor is operated for three periods every day before instability, wherein the period is 8 hours, the water is fed for 20 minutes, the stirring is carried out for 6 hours, the standing is carried out for 80 minutes, and the water is drained for 20 minutes. The drainage ratio was 33.3%. After the reactor is unstable, the period of 8h is adjusted to 12h, namely the stirring time of 6h is increased to 10h for continuous stirring. And after the activity is recovered, the solution is returned for 8 hours. The sludge is not actively discharged in the running process of the reactor.

(5) Result of operation

The reactor is started up and operated 156d, and the starting process can be divided into five stages according to the operation effect: a thallus autolysis stage (1-22 d), an activity retardation stage (23-83 d), an activity improvement stage (84-124 d), an activity stabilization stage (125-156 d) and a reactor instability recovery stage (156-208 d).

A thallus autolysis stage (1-22 d): inoculating sludge into the reactor to form secondary sedimentation tank return sludge, and performing thallus autolysis on aerobic bacteria in the return sludge under anaerobic conditions to cause effluent NH₄ ⁺The value of-N is higher than the feed water. Meanwhile, the thallus autolysis provides an electron donor for denitrifying bacteria to ensure NO in the effluent₂ ^-N concentration lower than feed water NO₂ ^--N concentration.

An activity retardation stage (23-83 d): the absence of the electron donor gradually inhibits the denitrification process, the activity of denitrifying bacteria is weakened, and the activity of anaerobic ammonia oxidation is not shown, so that the total nitrogen of inlet water and outlet water is basically the same, and NH is generated₄ ⁺The removal rate of-N slowly begins to decrease. At 62d of reactor operation, NH was measured₄ ⁺-N and NO₂ ^-N is removed simultaneously, and weak anammox activity begins in the reactor. The sludge inoculated at this stage changed from black to brown-yellow.

An activity-improving stage (84-124 d): in order to ensure the supply of the substrate, the concentration of the substrate entering water is continuously increased twice to ensure that NH is supplied₄ ⁺-N concentration 80mg/L, NO₂ ^-The concentration of N was 105.6 mg/L. And the addition of the seed mud obviously improves the activity of AnAOB, NH₄ ⁺-N and NO₂ ^-The removal rate of-N is also gradually increasing. NH (NH)₄ ⁺-N and NO₂ ^-The ratio of the degradation amount of-N is about 1: 1.4, because a small amount of residual denitrifying bacteria are still in the reactor, and the denitrifying bacteria utilize NO of the inlet water₂ ^-N is subjected to a denitrification reaction to yield NH₄ ⁺-N and NO₂ ^-The ratio of the amounts of-N degradation is higher than the theoretical value of 1: 1.32.

An activity stabilization stage (125-156 d): the denitrification reaction disappears gradually at this stage, but the reactor enters an activity stabilization stage due to the small amount of the AnAOB in the reactor and the long doubling time of the AnAOB. NH (NH)₄ ⁺The highest removal rate of-N can reach 83.3 percent, and NO₂ ^-The highest N removal rate can reach 96.4 percent, and the total nitrogen removal rate is also more than 60 percent on average.

And (5) a destabilization recovery stage (156-228 d): water inlet NH in the reactor₄ ⁺Increase of-N to 90mg/L, NO in feed water₂ ^-Increase of-N to 118.8mg/L (feed NH)₄ ⁺-N、NO₂ ^-N concentration ratio 1: 1.32, no change in cycle run time). At this time, FA in the reactor is up to 4.69mg/L and FNA is up to 2.68. mu.g/L, and the increase of FA and FNA inhibits the AnAOB activity and deteriorates the performance of the reactor. NH (NH)₄ ⁺The N removal rate is reduced to 22.1% from the original 82.3%, the TRE is reduced to 15.8% from the original 69.3%, and the effluent NO is₂ ^-The N concentration was increased to 30.2 mg/L. At run 176d, the influent substrate concentration was adjusted and the influent NH was applied₄ ⁺-N and NO₂ ^-the-N is respectively reduced to 70mg/L and 92.4 mg/L. After two weeks of operation, the period is prolongedThe hydraulic retention time is adjusted to 12h from 8h of the original operation cycle, namely 6h of stirring is improved to 10h of continuous stirring. The treatment effect of the reactor is obviously improved. And the operation period is readjusted to be a period of 8 hours, wherein the water is fed for 20 minutes, the stirring is carried out for 6 hours, the standing is carried out for 80 minutes, and the water is drained for 20 minutes. At run 206d, NH₄ ⁺The removal rate of-N is increased to 85.0 percent, and the effluent NO is₂ ^-N is almost zero, and the total nitrogen removal rate is as high as 73.4 percent. After culture acclimation of 228d, the AnAOB in the reactor is mainly Candidatus Brocadia, but only accounts for 13.26% of the flora. A small amount of anaerobic ammonium oxidation bacteria are enriched on the filler, and the color of the sludge is changed from black before inoculation to yellow brown. The anaerobic ammonia oxidation biofilm reactor was successfully started.

Claims

1. A starting method of an SBR anaerobic ammonia oxidation biomembrane reactor under the mode of low substrate concentration water inlet and gradually increased nitrogen load is characterized in that: the method starts a reactor by adopting a method of feeding water with low substrate concentration and gradually increasing nitrogen load, adds filler in the reactor to enrich anammox bacteria, and domesticates the anammox bacteria by increasing the nitrogen load in the starting process, and specifically comprises the following steps:

(1) pumping the simulated wastewater without the carbon source into the SBR reactor through a water inlet by virtue of a peristaltic pump;

(2) before starting, adding return sludge of a secondary sedimentation tank into the SBR reactor, and adding a small amount of anaerobic ammonium oxidation seed sludge during the operation of 83d (activity retardation stage);

(3) adding polyethylene filler (the filling ratio is about 30%) into the SBR reactor in the middle operation period;

(4) the SBR reactor adopts a low-substrate-concentration water inlet mode at the initial starting stage, the nitrogen load is adjusted according to the operation performance in the starting process, and anaerobic ammonium oxidation bacteria are enriched;

(5) treating the simulated wastewater, wherein the wastewater treatment operation cycle comprises the following steps: the water inlet stage, the reaction stage, the precipitation stage, the water outlet stage and the idle stage are circularly carried out.

(6) The reactor is started up for a total operation 208d, which can be divided into five stages: a thallus autolysis stage (1-22 d), an activity retardation stage (23-83 d), an activity improvement stage (84-124 d), an activity stabilization stage (125-156 d) and a reactor instability recovery stage (156-208 d). Wherein, the sludge is stored in a constant temperature refrigerator at 4 ℃ for 28 days when the 15 th (autolysis) stage is operated.

2. The method of claim 1, wherein the water-entering matrix in step (1) is composed of NH₄HCO₃And NaNO₂Providing NaHCO₃Used for providing a substrate and adjusting the pH, wherein the pH is controlled to be 7.5-8.5. The mineral composition in the simulated wastewater was as follows: KH (Perkin Elmer)₂PO₄30mg/L、MgSO₄·7H₂O 300mg/L、CaCl₂·2H₂O 36mg/L、NaHCO₃350mg/L and trace elements.

3. The method according to claim 1, wherein the SBR reactor is used in the step (1), the cylindrical organic glass container of the SBR reactor has an effective volume of 14L, a height of 600mm and a cylindrical diameter of 200mm, and a row of sampling ports with a spacing of 100mm are vertically arranged on the wall of the SBR reactor for sampling and draining. Stirring is carried out in the whole anaerobic reaction stage.

4. The method according to claim 1, wherein the amount of seeded secondary sedimentation sludge (MLSS is 4500mg/L) in step (2) accounts for 60% of the volume of the reactor, and the amount of seeded anaerobic ammonia oxidation sludge accounts for one-fiftieth of the volume of the reactor.

5. The method as claimed in claim 1, wherein the filler in the step (3) is High Density Polyethylene (HDPE) filler with a specific gravity of 0.95g/cm and a diameter of 10 x 10mm³Above, the specific surface area is more than 500m²/m³The filling ratio of the inoculation filler is about 30 percent.

6. The method of claim 1, wherein the adjusting in step (4) is performed by adjusting influent substrate concentration or hydraulic retention timeNitrogen loading. The concentration of the water inlet substrate is controlled to be about 50mg/L and 66mg/L respectively in the starting stage. The thalli autolysis stage is to feed water NH₄ ⁺Increase of-N to 60mg/L, NO₂ ^-the-N is increased to 79.2mg/L, and the effluent quality is not improved. Two consecutive increases of feed water NH in the activity-increasing stage₄ ⁺-N、NO₂ ^-The concentration of-N was 80mg/L and 105.6 mg/L. In the activity stabilization stage, NH is controlled by feeding water₄ ⁺-N and NO₂ ^-The concentration of-N is 70mg/L and 92.4mg/L respectively, and NH can be generated₄ ⁺The average removal rate of-N is more than 80%, and the average TRE is more than 63%. Subsequently, in order to ensure the supply of the substrate and to further increase the concentration of the substrate in the reactor, water NH is fed in₄ ⁺Increase of-N to 90mg/L, NO in feed water₂ ^-The increase in N to 118.8mg/L, no change in the cycle run time, and deterioration in the reactor performance occurred. Then the feed water NH₄ ⁺-N and NO₂ ^-N is respectively reduced to 70mg/L and 92.4mg/L, the hydraulic retention time is prolonged, the original 8h operation period is adjusted to 12h, and the treatment effect of the reactor is improved. The running period is then readjusted to a period of 8 h. NH at reaction run 206d₄ ⁺The removal rate of-N is increased to 85.0 percent, and the effluent NO is₂ ^-N is almost zero and TRE is as high as 73.4%.

7. The method of claim 1, wherein in the step (5), the four stages before the start-up of the reactor are operated for three cycles each day, one cycle is 8 hours in length and comprises water feeding for 20 minutes, stirring for 6 hours, standing for 80 minutes and water draining for 20 minutes, the water draining ratio is set to be 33.3 percent, the HRT is 24 hours, and the sludge is not actively drained during the operation of the reactor. In the last stage, when the reactor is unstable, the period of 8h is adjusted to 12h (namely 6h stirring is increased to 10h continuous stirring), and after the activity is recovered, the period is adjusted back to 8h again.