Methods for Adding Nutrients to Promote the Resistance of Anaerobic Ammonium Oxidation Granular Sludge to Heavy Metal Stress

Abstract

This invention discloses a method for adding nutrients to anammox granular sludge to enhance its resistance to heavy metal stress, belonging to the field of wastewater biological treatment. The method includes: periodically adding a nutrient solution to an anammox granular sludge system that has been or may be subsequently subjected to heavy metal stress, thereby improving the sludge's ability to resist heavy metal stress; the nutrient solution contains at least one of proline, arginine, glutamic acid, lysine, and nicotinic acid; and the concentration of each nutrient component in the anammox granular sludge system after adding the nutrient solution is 5-50 μM. This invention is easy to operate. By periodically adding an appropriate amount of nutrient solution to the anammox granular sludge, it promotes the sludge to maintain good activity after heavy metal stress, improves its resistance to heavy metals, alleviates the negative effects of stress, and provides a new control method for actual process operation.

Description

Technical Field

[0001] This invention belongs to the field of biological wastewater treatment, specifically relating to a method for adding nutrients to promote anaerobic ammonia oxidation granular sludge to resist heavy metal stress. Background Technology

[0002] Anammox, with its advantages of low energy consumption and low carbon footprint, has become an upgraded technology for biological nitrogen removal from wastewater. Currently, over 90% of anammox processes are applied in the form of granular sludge. Granular sludge is a granular bioaggregate naturally formed by microorganisms during long-term operation due to external factors such as hydraulic shear forces. The granular form allows for the stratification of internal and external functional microorganisms and is conducive to microbial retention. Anammox processes are currently mostly operated in high-nitrogen-load environments, such as various industrial wastewaters and sludge digestion liquids. These wastewaters often contain various heavy metal ions, which remain in the discharged wastewater due to production processes. These heavy metal ions are toxic to the various microorganisms in the anammox community. High concentrations of heavy metal ions not only directly lead to a deterioration in nitrogen removal efficiency but can also cause the disintegration of granular sludge, resulting in a significant loss of functional microorganisms and increased process costs. Therefore, developing methods to enhance the heavy metal resistance and promote the recovery of anammox granular sludge is of great significance for the efficient, economical, and stable operation of anammox processes.

[0003] Regarding methods for recovery after anaerobic ammonia oxidation stress, a search revealed relevant patent applications. For example, Chinese Patent Publication No. CN202211402981 discloses a method for promoting the recovery of anaerobic ammonia oxidizing bacteria after iron ion inhibition using betaine and EDTA-2Na. The specific steps are as follows: Betaine is added intermittently to the water containing the anaerobic ammonia oxidizing bacteria. The intermittent addition method includes alternating continuous addition and paused addition, with the continuous addition time controlled at 8-12 days and the paused addition time controlled at 3-5 days. EDTA-2Na is added before adding betaine to the water. Furthermore, Chinese Patent Publication No. CN202211242932 discloses a rapid recovery method for heavy metal inhibition in anaerobic ammonia oxidation, the specific steps of which are as follows: Heavy metal inhibition in anaerobic ammonia oxidation is rapidly restored by adding particulate heavy metal ion exchange resin to the system.

[0004] The methods reported in the above-mentioned publicly filed patent cases all have a certain impact on the resistance of anaerobic ammonia oxidizing bacteria to heavy metal ion inhibition. However, the added EDTA-2Na and particulate adsorption resin (particle size 0.5-1mm) may cause secondary pollution of the effluent water quality, and the resin recovery process is relatively complex.

[0005] By analyzing the changes in metabolite composition during the inhibition and natural recovery processes of anaerobic ammonia-oxidizing bacteria by heavy metals, the types of nutrients required by these bacteria during stress recovery can be determined. Based on this, a nutrient agent can be constructed to promote the resistance of anaerobic ammonia-oxidizing bacteria to heavy metal stress. Furthermore, by utilizing small-molecule substances required by anaerobic ammonia-oxidizing bacteria during heavy metal stress, a novel method for adding nutrients to promote the resistance of anaerobic ammonia-oxidizing granular sludge to heavy metal stress can be invented. Summary of the Invention

[0006] The purpose of this invention is to address the problem of decreased denitrification efficiency caused by various heavy metal ions in the water body during current anammox denitrification processes, and to provide a nutrient addition method to promote the resistance of anammox granular sludge to heavy metal stress.

[0007] The specific technical solution adopted in this invention is as follows:

[0008] This invention provides a method for adding nutrients to promote the resistance of anaerobic ammonia oxidation granular sludge to heavy metal stress, as detailed below:

[0009] Adding nutrient solutions periodically to anaerobic ammonia oxidation granular sludge systems that have been or may be subjected to heavy metal stress can improve the ability of anaerobic ammonia oxidation granular sludge to resist heavy metal stress.

[0010] The nutrient solution is an aqueous solution containing nutrient components, which are at least one of proline, arginine, glutamic acid, lysine, and nicotinic acid. In the anaerobic ammonia oxidation granular sludge system after adding the nutrient solution, the concentration of each nutrient component is 5-50 μM.

[0011] Preferably, the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution is in a state of heavy metal stress.

[0012] Furthermore, the nutrient solution is added every 12 hours in batches.

[0013] Furthermore, after the nutrient solution is added to the anaerobic ammonia oxidation granular sludge system for the first time, the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the system are continuously measured by colorimetry to determine the denitrification efficiency of the granular sludge in the system before and after the reaction; if the denitrification efficiency has not yet recovered to the preset level, the nutrient solution needs to be added periodically.

[0014] Preferably, the anaerobic ammonia oxidation granular sludge system is in a healthy state before the addition of the nutrient solution.

[0015] Furthermore, the nutrient solution is added once every five days, with each addition lasting one day.

[0016] Preferably, during the reaction process of adding the nutrient solution to the anaerobic ammonia oxidation granular sludge system, the pH value is 6.5-7.8 and the temperature is 20-40℃.

[0017] Preferably, in the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution, the sludge concentration is MLSS: 500-5000 mg / L, wherein the relative abundance of anaerobic ammonia oxidation bacteria is 5%-50%.

[0018] Preferably, in the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution, the nitrogen concentration ranges from 100-800 mg / L, and the NH4+ concentration is [missing information]. + -N and NO2 - The molar concentration ratio of -N was maintained at 1:(1.1 to 1.3).

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) This invention uses a self-developed nutrient solution for process dosing control. The regular addition of the nutrient solution can reduce the nitrogen removal efficiency of the stressed anammox granular sludge system by only 20%-30%, while the control group (i.e., the stressed anammox granular sludge system without added nutrient solution) reduces it by more than 50%. Long-term regular addition promotes the stability of granular sludge particle size and avoids disintegration after stress.

[0021] (2) In the method of the present invention, the addition of nutrient solution can be effectively utilized by various microorganisms in the anaerobic ammonia oxidation community in the anaerobic ammonia oxidation granular sludge system, and the overall community's resistance to heavy metal ions is increased.

[0022] (3) The nutrient components used in this invention are all substances required by the human body or microorganisms. After being added and used, they have no other harmful effects on water bodies except for the recovery effect on granular sludge under heavy metal stress. They are environmentally friendly and easy to promote.

[0023] (4) The nutrient ingredients used in this invention are all commercial products, which are relatively inexpensive and easy to obtain. Attached Figure Description

[0024] Figure 1 This is a comparison of the denitrification activity of nutrient addition during the continuous short-term heavy metal stress of anaerobic ammonia oxidation particles in Example 2.

[0025] Figure 2 This is a comparison of the resistance to heavy metal stress in the long-term anaerobic ammonia oxidation granular sludge reactor after periodic addition of nutrients, as shown in Example 3. Detailed Implementation

[0026] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0027] This invention provides a method for adding nutrients to promote the resistance of anaerobic ammonia oxidation granular sludge to heavy metal stress. The method is as follows:

[0028] The prepared nutrient solution is periodically added to the anaerobic ammonia oxidation granular sludge system that has been or may be subjected to heavy metal stress, thereby improving the anaerobic ammonia oxidation granular sludge's ability to resist heavy metal stress. The nutrient solution is an aqueous solution containing nutrient components, at least one of proline, arginine, glutamic acid, lysine, and nicotinic acid. In the anaerobic ammonia oxidation granular sludge system after adding the nutrient solution, the concentration (i.e., the final concentration) of each nutrient component is 5-50 μM.

[0029] As a preferred embodiment of the present invention, the nutrient composition includes five components: proline, arginine, glutamic acid, lysine, and niacin, and the final concentration of each component is 5-50 μM.

[0030] In a preferred embodiment of the present invention, the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution is in a state of heavy metal stress. At this time, the nutrient solution is added every 12 hours in batches. Regularly adding the nutrient solution to the anaerobic ammonia oxidation granular sludge system under heavy metal stress can prevent a significant decrease in the activity of the granular sludge in the system and promote activity recovery and particle size maintenance.

[0031] In practical use, after the initial addition of nutrient solution to the anammox granular sludge system, the activity status of the anammox granular sludge should be checked periodically until its activity recovers to the target state. It should be noted that the target state refers to the desired state, that is, the activity state of the anammox granular sludge as defined or required before treatment. This can be adjusted according to actual conditions and is not limited here. In other words, after the initial addition of nutrient solution to the anammox granular sludge system, the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the system can be continuously measured using colorimetry to determine the denitrification efficiency of the granular sludge before and after the reaction, thereby obtaining the activity recovery status of the granular sludge microorganisms in the system. If the denitrification efficiency has not yet recovered to the preset level, it is necessary to continue adding nutrient solution periodically.

[0032] In a preferred embodiment of the present invention, the anaerobic ammonia oxidation granular sludge system is in a healthy state before the addition of the nutrient solution. At this time, the nutrient solution is added every five days, with each addition lasting one day. Regularly adding the nutrient solution to the healthy anaerobic ammonia oxidation granular sludge system can promote the stability of the granular sludge particle size in the system and avoid disintegration under stress.

[0033] In a preferred embodiment of the present invention, during the reaction process of adding nutrient solution to the anaerobic ammonia oxidation granular sludge system, the pH value of the system should be maintained at 6.5-7.8 and the temperature at 20-40℃.

[0034] As a preferred embodiment of the present invention, in the anaerobic ammonia oxidation granular sludge system before the addition of nutrient solution, the sludge concentration is MLSS: 500-5000 mg / L, wherein the relative abundance of anaerobic ammonia oxidation bacteria is 5%-50%.

[0035] In a preferred embodiment of the present invention, the nitrogen concentration in the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution is in the range of 100-800 mg / L, and the NH4+ concentration is... + -N and NO2 - The molar concentration ratio of -N was maintained at 1:(1.1 to 1.3).

[0036] The methods and effects of the present invention will be specifically illustrated below through examples.

[0037] Example 1

[0038] This embodiment compares the effect of different nutrient components on the activity decay rate of anaerobic ammonia oxidation sludge after short-term heavy metal stress at different dosages to verify the effectiveness of different components and determine the final nutrient component ratio. The method includes the following steps:

[0039] Step 1) Anaerobic ammonia oxidation granular sludge from an actual wastewater biochemical treatment section was used for a reactor operation test. (The reaction system in this experiment was a 100mL serum bottle, pH was maintained at 7.3-7.7, temperature was 37℃, and initial NH4+ was...) + -N, NO2 - -N concentrations of 30 mg N / L and 40 mg N / L, NH4 + -N and NO2 - The molar concentration ratio of -N was approximately 1:1.3, and the sludge concentration was MLSS: 800 mg / L. All comparative experiments maintained the same temperature and uniform influent conditions. The same concentrations of copper, zinc, and nickel (3 mg / L each) were added to each test serum bottle.

[0040] Step 2) Add different doses of nutrient components (such as proline, glutamic acid, etc.) to the experimental group. Then start the shake-flask reaction.

[0041] Step 3) After 12 hours of reaction, the specific activity of the granular sludge in the stressed anammox granular sludge system was detected, and the anammox activity decay rate was calculated (100% - specific activity at the end of the experiment / initial specific activity * 100%).

[0042] The experimental results are as follows:

[0043] According to the results shown in Table 1, various amino acids and nicotinic acid at dosages of 5-50 μM all reduced the activity decay rate of anaerobic ammonia oxidation granular sludge after being subjected to combined stress from three heavy metals: copper, zinc, and nickel.

[0044] Table 1. Activity decay rate (%) of anaerobic ammonia oxidation granular sludge under different nutrient dosages.

[0045]

[0046] Example 2

[0047] This embodiment demonstrates the effectiveness of the nutrient agent in this invention for resisting heavy metal stress in anammox granular sludge by comparing sludge activity during short-term heavy metal stress, including the following steps:

[0048] Step 1) The anammox granular sludge involved in this experiment consisted of anammox granular sludge obtained from the actual engineering site (AMX1) and anammox granular sludge cultured in the laboratory for a long period of time (AMX2). (The reaction system in this experiment was a 100mL serum bottle, with the pH maintained at 7.3-7.7, the temperature at 37℃, and the initial NH4+.) + -N, NO2 - -N concentrations of 30 mg N / L and 40 mg N / L, NH4 + -N and NO2 - The molar concentration ratio of -N was approximately 1:1.3, and the sludge concentration was MLSS: 800 mg / L. All comparative experiments maintained the same temperature and uniform influent conditions. The same concentrations of copper, zinc, and nickel (3 mg / L each) were added to each test serum bottle.

[0049] Step 2) Add a nutrient solution (an aqueous solution containing five nutrient components: proline, arginine, glutamic acid, lysine, and niacin, each at a concentration of 10 μM) to the experimental group (i.e., the nutrient group). Then, begin the shake-flask reaction. After 12 hours of reaction, wash the sludge, add the heavy metals and the corresponding nutrient solution again, and react for another 12 hours. Repeat this cycle three times.

[0050] Step 3) Detect the specific activity of granular sludge in the stressed anammox granular sludge system and calculate the anammox activity decay rate. The calculation formula is 100% - specific activity at the end of the test / initial specific activity * 100%.

[0051] In this embodiment, the experimental results are as follows:

[0052] according to Figure 1 As shown, after repeated exposure to the combined stress of copper, zinc, and nickel, the specific activity of the anammox granular sludge in the control group (i.e., normally operating and without any added nutrients) decreased by 29.83% and 39.49% in the actual engineering field (AMX1) and laboratory (AMX2) anammox granular sludge, respectively. In contrast, the specific activity of the anammox granular sludge in the experimental group of this embodiment, with the assistance of nutrient solution, decreased by only 20.24% and 23.42%, respectively. This indicates that the nutrient solution assistance can significantly improve the resistance of anammox granular sludge to heavy metals.

[0053] Example 3

[0054] This embodiment demonstrates the effectiveness of the nutrient solution in resisting heavy metal stress in anammox granular sludge by comparing the operating status during long-term operation, including the following steps:

[0055] Step 1) Anaerobic ammonia oxidation granular sludge from an actual wastewater biochemical treatment plant was used for a reactor operation test. The reaction system was a 500 mL UASB reactor, with the pH maintained at 7.3-7.7, the temperature at 37℃, and the initial NH4+. + -N, NO2 - -N concentrations of 100 mg N / L and 130 mg N / L, NH4 + -N and NO2 - The molar concentration ratio of -N was approximately 1:1.3, and the initial sludge concentration was MLSS: 3000 mg / L. All comparative experiments maintained the same temperature and uniform influent conditions. Nutrient solution was added to the experimental group (reactor 1), while reactor 2 served as the control group.

[0056] Step 2) Add the nutrient solution (an aqueous solution containing five nutrients: proline, arginine, glutamic acid, lysine, and niacin, with each component having a concentration of 5 μM) to the reactor once every 5 days for 1 day each time. The nutrient solution is added by a feed pump.

[0057] Step 3) On the 68th day of reactor operation, introduce 3 mg / L of each of copper, zinc and nickel heavy metal ions into the feed water for stress, and the stress time is 24 hours.

[0058] Step 4) Subsequently, water quality operation is sampled regularly and continuously monitored, the specific activity of granular sludge is calculated, and the size of granular sludge is measured.

[0059] Table 2. Size of Granular Sludge

[0060]

[0061] like Figure 2 As shown, after the introduction of heavy metal stress on day 68, the nitrogen removal efficiency of reactors 1 and 2 decreased significantly. The removal efficiency of the nutrient group (reactor 1) decreased by approximately 30%, while the removal efficiency of the control group (reactor 2, i.e., operating normally without any nutrient solution added) decreased by more than 50%. After stress, the nitrogen removal efficiency of the nutrient group was able to rapidly recover to 90% of its original level within 2 days, while the control group required a longer time.

[0062] The activity and particle size of the granular sludge, as shown in Table 2 above, indicate that the granular sludge size in reactor 1 was significantly larger than that in reactor 2 under continuous nutrient solution addition (1403.5 μm vs 1308.3 μm on day 32). Even after heavy metal stress, the granular sludge size did not decrease significantly (1289.8 μm vs 1116.0 μm on day 70). Simultaneously, the activity trend of the granular sludge was similar to the overall nitrogen removal efficiency of the reactors; after heavy metal stress (day 70), the specific activity of the granular sludge in reactor 1 was significantly higher than that in reactor 2 (85.7 vs 55.0 mg N / g vs s / d).

[0063] The above results indicate that regular nutrient solution supplementation has a good effect on resisting heavy metal stress in long-term anammox granular sludge reactors. Specifically, it enhances anammox activity under both healthy conditions and after stress. Simultaneously, the addition of nutrient solution helps maintain the morphology of the anammox granular sludge.

[0064] The method of this invention is easy to operate. By periodically adding nutrient solution to the anaerobic ammonia oxidation granular sludge reactor, it can effectively achieve rapid recovery of anaerobic ammonia oxidation activity and sludge particle formation, alleviate the negative effects of stress, and provide a new control method for actual process operation.

[0065] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for adding nutrients to anaerobic ammonium oxidation granular sludge to enhance its resistance to heavy metal stress, characterized in that, Specifically as follows: Adding nutrient solutions periodically to anaerobic ammonia oxidation granular sludge systems that have been or will be subjected to heavy metal stress can improve the ability of anaerobic ammonia oxidation granular sludge to resist heavy metal stress. The nutrient solution is an aqueous solution containing nutrient components, which are at least one of proline, arginine, glutamic acid, lysine, and nicotinic acid. In the anaerobic ammonia oxidation granular sludge system after adding the nutrient solution, the concentration of each nutrient component is 5-50 μM.

2. The method for adding nutrients to promote anaerobic ammonia oxidation granular sludge's resistance to heavy metal stress according to claim 1, characterized in that, Before the addition of the nutrient solution, the anaerobic ammonia oxidation granular sludge system was under heavy metal stress; the nutrient solution was added every 12 hours in batches.

3. The method for adding nutrients to promote anaerobic ammonia oxidation granular sludge's resistance to heavy metal stress according to claim 1, characterized in that, The anaerobic ammonia oxidation granular sludge system was in a healthy state before the addition of the nutrient solution; the nutrient solution was added once every five days, with each addition lasting one day.

4. The method for adding nutrients to promote anaerobic ammonia oxidation granular sludge's resistance to heavy metal stress according to claim 1, characterized in that, During the reaction process of adding the nutrient solution to the anaerobic ammonia oxidation granular sludge system, the pH value is 6.5-7.8 and the temperature is 20-40℃.

5. The method for adding nutrients to promote anaerobic ammonia oxidation granular sludge's resistance to heavy metal stress according to claim 1, characterized in that, In the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution, the sludge concentration is MLSS: 500-5000 mg / L, and the relative abundance of anaerobic ammonia oxidation bacteria is 5%-50%.

6. The method for adding nutrients to promote anaerobic ammonia oxidation granular sludge's resistance to heavy metal stress according to claim 1, characterized in that, In the anaerobic ammonia oxidation granular sludge system before the addition of the nutrient solution, the nitrogen concentration ranges from 100-800 mg / L, and the NH4+ concentration is... + -N and NO2 - The molar concentration ratio of -N was maintained at 1:(1.1~1.3).

7. The method for adding nutrients to promote anaerobic ammonia oxidation granular sludge's resistance to heavy metal stress according to claim 2, characterized in that, After the nutrient solution was added to the anaerobic ammonia oxidation granular sludge system for the first time, the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the system were continuously measured by colorimetry to determine the denitrification efficiency of the granular sludge in the system before and after the reaction. If the denitrification efficiency has not yet recovered to the preset level, it is necessary to continue to add nutrient solution regularly.

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