A method for evaluating activated sludge settling performance and controlling sludge bulking

Abstract

The present invention relates to the technical field of sewage treatment, and specifically to a method for evaluating the settling performance of activated sludge and controlling sludge bulking. The method of the present invention evaluates the settling performance of activated sludge by defining a "sludge escape index" SEI, and makes corresponding process adjustments based on the evaluation results, thereby slowing down or even avoiding sludge bulking. In the method of the present invention, when the sludge is slightly expanded, the solid surface load of the secondary sedimentation tank is reasonably adjusted; when the sludge is moderately expanded, micropowder is added to aid sedimentation; when the sludge is severely expanded, additional flocculants are added to improve the sludge settling performance; when the sludge is severely expanded, emergency measures such as adding a carbon source are adopted for treatment. Through the method of the present invention, the settling performance of the sludge in the secondary sedimentation tank can be effectively evaluated, and sludge bulking can be controlled in a timely and effective manner, which is of great significance to maintaining the stable operation of the production process.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a method for evaluating activated sludge settling performance and controlling sludge bulking. Background Art

[0002] Municipal sewage treatment plants are an indispensable part of modern urban infrastructure, with their main task being to treat and purify urban domestic sewage and industrial wastewater. However, during the sewage treatment process, the problem of sludge bulking caused by the deterioration of sludge settling performance has always been a technical challenge. Sludge settling performance has a significant impact on the operating efficiency and effluent quality of sewage treatment plants. Sludge refers to the semi-solid material separated from wastewater during the sewage treatment process. In the secondary treatment process, rapid sludge settling not only improves the treatment efficiency of the biological reactor, but also reduces the load on subsequent treatment units. However, in actual operation, many sewage treatment plants face the problem of ineffective supervision of sludge settling performance and extensive control of the settling effect, which leads to the inability to timely detect and resolve the deterioration of settling performance.

[0003] Many factors influence sludge settling performance. Currently, the Sludge Volume Index (SVI) is an important indicator for measuring activated sludge settling performance and is commonly used to assess sludge bulking and coagulation settling performance. Sludge bulking is often associated with high SVI values, but the specific SVI threshold varies depending on the sewage treatment plant and treatment process, and the range is large (150-250 mL / g). The SVI needs to be set based on the actual project, which is a time-consuming process and is not universal across projects. Therefore, how to accurately and quickly evaluate the settling performance of activated sludge in actual projects is a technical problem that needs to be solved in existing engineering practices.

[0004] Furthermore, factors such as the suspended solids content, organic matter concentration, water temperature, pH value, and the type and number of microorganisms in wastewater all affect sludge settling performance. For example, high concentrations of organic matter increase the viscosity of the mixed liquor, hindering sludge settling. A pH value outside the neutral range can also reduce microbial activity, affecting sludge structure and, consequently, settling performance. Common measures to address sludge settling performance issues include: optimizing process parameters, such as adjusting the influent load, controlling aeration volume, and adjusting pH; using chemical agents, such as flocculants and coagulants, to enhance flocculation and settling rate; and employing advanced biological treatment technologies, such as aerobic granular sludge technology. Due to the numerous factors that contribute to activated sludge bulking and reduced settling performance, process optimization requires a long cycle, making it difficult to meet the requirements of sewage treatment plants. Chemical agents, due to their limited active ingredients and low molecular weight, also fail to rapidly improve sludge settling performance and increase chemical costs for sewage treatment plants. Aerobic granular sludge is currently mainly used in SBR systems and has not yet been widely applied in continuous flow systems. Therefore, how to efficiently and quickly control sludge settling performance is also a technical problem that needs to be solved in existing engineering practices.

[0005] In summary, sludge settling performance is a key challenge in urban wastewater treatment, requiring comprehensive consideration of multiple factors and approaches. Therefore, the present invention provides a new metric for evaluating sludge settling performance, as well as a route and method for maintaining activated sludge settling performance, offering a systematic and effective solution to activated sludge bulking. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for evaluating the settling performance of activated sludge and controlling sludge bulking, so as to solve the problems that the existing use of the sludge index (SVI) to evaluate the sludge settling performance is time-consuming and not universal in actual engineering projects, which brings inconvenience to the actual engineering, and the existing sludge settling performance control method is not accurate and efficient enough.

[0007] To achieve the above object, the present invention adopts the following technical solution: a method for evaluating the settling performance of activated sludge, comprising the following steps:

[0008] S1. Define the activated sludge settling performance evaluation indicator "sludge escape index" SEI;

[0009] S11. Determine the mud level height H, m of the secondary sedimentation tank; the solid surface load Q, kg / (m 2 *h); where h is hour;

[0010] SEI=H / Q, unit is m 3 *h / kg;

[0011] The physical meaning of the "sludge escape index" is: the actual sludge layer height corresponding to the current solid surface load of the secondary sedimentation tank of the sewage treatment plant under the dynamic hydraulic conditions of continuous water inflow, backflow and outflow;

[0012] The mud level height is defined as follows: the bottom plane of the effective water depth of the secondary sedimentation tank is used as the reference plane, and the height of the mud surface exceeding the reference plane is defined as the mud level height;

[0013] S2. Define the threshold value of “sludge escape index” TSEI;

[0014] S21. Check the maximum mud level H0, m designed for the secondary sedimentation tank; the solid surface load Q0, kg / (m designed for the secondary sedimentation tank). 2 *h);

[0015] TSEI=H0 / Q0, unit is m 3 *h / kg;

[0016] S3. Compare the “sludge escape index” measured by S1 with the threshold value of the “sludge escape index” defined by S2 to evaluate the settling performance of the activated sludge.

[0017] Furthermore, in the S3, when SEI≤TSEI, the sludge does not swell; when TSEI<SEI≤(1+H2 / 3H0)TSEI, the sludge swells slightly; when (1+H2 / 3H0)TSEI<SEI≤(1+2H2 / 3H0)TSEI, the sludge swells moderately; when (1+2H2 / 3H0)TSEI<SEI≤(1+H2 / H0)TSEI, the sludge swells severely; when SEI>(1+H2 / H0)TSEI, the sludge swells severely.

[0018] Among them, H2=H3-H0-H1;

[0019] Where, H3 is the effective water depth of the secondary sedimentation tank; H0 is the maximum mud level height designed for the secondary sedimentation tank; and H1 is the mud level protection height of the secondary sedimentation tank.

[0020] Furthermore, when the sludge does not swell, the current process state is maintained without adjustment, and the mud level height and sludge escape index of the secondary sedimentation tank are continuously monitored; when the sludge swells slightly, relatively reasonable indicators and parameters are maintained, and the solid surface load of the secondary sedimentation tank is reasonably adjusted according to the mud level height of the secondary sedimentation tank; when the sludge swells moderately, on the basis of the mild expansion treatment measures, the powder addition system begins to add an appropriate amount of powder to aid sedimentation, and at the same time, the residual sludge discharge is appropriately increased to accelerate sludge renewal; when the sludge swells severely, on the basis of the moderate expansion treatment measures, the proportion of powder addition is appropriately increased, and at the same time, an appropriate amount of flocculant is started; when the sludge swells severely, on the basis of the severe expansion treatment measures, the proportion of flocculant addition is appropriately increased, and at the same time, an appropriate amount of carbon source agent is started to improve the sludge nutritional environment. In addition, according to actual conditions, emergency measures including surpassing the primary sedimentation tank, surpassing the grit chamber and reducing the water intake can be taken.

[0021] Furthermore, the flocculant includes PAC and PAM.

[0022] Furthermore, the micropowder dosing system mixes the micropowder and water evenly and then transports the micropowder to the dosing point.

[0023] Furthermore, the micropowder includes organic microparticles and inorganic microparticles, the organic microparticles are one or more of activated coke powder, waste activated carbon powder, and blue carbon powder, and the inorganic microparticles are one or more of bentonite powder, zeolite powder, sludge incineration slag powder, and dried sludge powder.

[0024] Furthermore, the particle size of the micropowder is 75-150 microns and the density is 1.1-2.2 g / cm 3 .

[0025] Furthermore, the micropowder is activated coke powder.

[0026] Furthermore, the activated coke powder is modified, and the preparation of the modified activated coke powder comprises the following steps:

[0027] S1. Adding activated coke powder to a starch solution, stirring and ultrasonically impregnating the activated coke powder to obtain an impregnation mixture;

[0028] S2, subjecting the S1 impregnation mixture to microwave treatment;

[0029] S3, separating the solid-liquid mixture after the microwave treatment in S2 and drying it to obtain the modified activated coke powder of the present invention.

[0030] Furthermore, the power of the microwave is 600-1000W.

[0031] Beneficial effects of the present invention:

[0032] 1. The method of the present invention proposes an indicator called "sludge escape index" to objectively evaluate the dynamic settling performance of sludge. It more directly and objectively reflects the actual mud-water separation effect of the secondary sedimentation tank. It has stronger adaptability and can be applied to secondary sedimentation tanks with different loads, making it more convenient for actual engineering applications. The process adjustment scheme of controlling sludge settling performance through a cascade strategy helps maintain the stability of the activated sludge system and timely warns and controls sludge bulking.

[0033] 2. The method of the present invention uses micropowder to aid sedimentation and improve the sedimentation performance of sludge. In particular, the method of the present invention uses modified activated coke micropowder, which has better adsorption and affinity for organic matter in sewage and activated sludge, can form granular sludge faster and better, and at the same time improve the sludge's removal efficiency of pollutants;

[0034] 3. The method of the present invention can evaluate and control the settling performance of activated sludge in urban sewage treatment systems, improve system stability, and solve the problem of high SS or even sludge leakage in the effluent of the secondary sedimentation tank due to sludge bulking. At the same time, it can also significantly improve sewage treatment efficiency and reduce treatment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a diagram showing the actual corresponding relationship between the various defined heights in the secondary sedimentation tank of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0037] The principle of the technical solution of the present invention:

[0038] In the method of the present invention, the "Sludge escape index" (SEI) is defined and the calculation formula is as follows:

[0039] SEI=H / Q

[0040] Where, H is the mud level height of the secondary sedimentation tank, in meters;

[0041] The bottom plane of the effective water depth of the secondary sedimentation tank is taken as the reference plane, and the height of the mud surface exceeding the reference plane is defined as the mud level height; wherein, the effective water depth of the secondary sedimentation tank is the conventional parameter in the design of the existing secondary sedimentation tank;

[0042] Q is the solid surface load Q of the secondary sedimentation tank, unit is kg / (m 2 *h); where h is hours.

[0043] SEI is the actual mud level height of the sludge layer corresponding to the current solid surface load of the secondary sedimentation tank of a sewage treatment plant under the dynamic hydraulic conditions of continuous water inflow, backflow and outflow of the secondary sedimentation tank.

[0044] And define the threshold value of "sludge escape index" TSEI, the calculation formula is as follows:

[0045] TSEI=H0 / Q0

[0046] Where, H0 is the designed mud level height of the secondary sedimentation tank, in m;

[0047] Q0 is the designed solid surface load of the secondary sedimentation tank, in kg / (m 2 *h).

[0048] Compared with the traditional sludge index (SVI), the new sludge settling performance index SEI more directly and objectively reflects the actual mud-water separation effect of the secondary sedimentation tank. It is used to guide production and has stronger adaptability and can be applied to secondary sedimentation tanks with different loads.

[0049] Based on the sludge settling performance index SEI defined above, the method of the present invention proposes a process adjustment scheme for controlling sludge settling performance using a cascade strategy; by comparing SEI with TSEI, the sludge settling performance degree is divided into five levels: no expansion, mild expansion, moderate expansion, severe expansion and serious expansion.

[0050] When SEI≤TSEI, the sludge does not expand. At this time, the current process state is maintained without adjustment, and the sludge level height and sludge escape index of the secondary sedimentation tank are continuously monitored;

[0051] When TSEI<SEI≤(1+H2 / 3H0)TSEI, the sludge expands slightly. At this time, various indicators and parameters should be maintained at a reasonable level. According to the mud level in the secondary sedimentation tank, the solid surface load of the secondary sedimentation tank should be reasonably adjusted.

[0052] When (1+H2 / 3H0)TSEI<SEI≤(1+2H2 / 3H0)TSEI, the sludge is moderately expanded. At this time, on the basis of the mild expansion treatment measures, appropriate amount of micro powder is added to aid sedimentation, and the discharge of residual sludge is appropriately increased to accelerate sludge renewal;

[0053] When (1+2H2 / 3H0)TSEI<SEI≤(1+H2 / H0)TSEI, the sludge is severely expanded. At this time, based on the moderate expansion treatment measures, the proportion of micropowder should be appropriately increased, and flocculants such as PAC (polyaluminum chloride) and PAM (polyacrylamide) should be added in appropriate amounts;

[0054] When SEI> (1+H2 / H0) TSEI, the sludge swells severely. On the basis of the severe swelling treatment measures, the proportion of flocculant addition should be appropriately increased; at the same time, carbon source agents should be added in appropriate amounts to improve the sludge nutritional environment; in addition, emergency measures such as surpassing the primary sedimentation tank, surpassing the grit chamber and reducing the water intake can be taken according to the actual situation.

[0055] The above, such as Figure 1 As shown, H2=H3-H0-H1;

[0056] Where, H3 is the effective water depth of the secondary sedimentation tank; H0 is the maximum mud level height designed for the secondary sedimentation tank; and H1 is the mud level protection height of the secondary sedimentation tank.

[0057] In the method of the present invention, a micropowder dosing system is used to add micropowder. During the process, the micropowder is lifted to a mixing tank through a feeding system, such as a bucket elevator, and then a delivery pump is used to pump the secondary effluent of the sewage treatment into the mixing tank for micropowder mixing. After the mixing is uniform, the effluent is delivered to the dosing point by a pump.

[0058] In the method of the present invention, the micropowder can be either organic microparticles or inorganic microparticles. The organic microparticles can be activated coke powder, waste activated carbon powder, blue carbon powder, etc., and the inorganic microparticles can be bentonite powder, zeolite powder, sludge incineration slag powder, dried sludge powder, etc., and the particle size must be less than 75 microns.

[0059] Through production exploration, the method of the present invention also proposes a modified activated coke powder.

[0060] Aerobic granular sludge has been widely researched to address sludge bulking. However, due to its unique hydraulic and control requirements, it is difficult to retrofit existing projects and difficult to promote on a large scale in new projects. Therefore, researchers have developed granular sludge technology using inorganic media particles as its core. While this technology can form granular sludge without requiring strict hydraulic and control conditions, the introduction of large quantities of inorganic particles can significantly impact the operation of sludge treatment and disposal equipment, significantly increasing the ash content in the sludge.

[0061] The modified activated coke micropowder, which is mainly composed of activated coke micropowder and prepared by carbon source impregnation and microwave modification, is a good organic medium particle sedimentation aid material. It is more friendly to equipment in sludge treatment and disposal, especially in sludge combustion resource disposal. The organic medium particle material will be a good fuel, which will help the full combustion of sludge and improve the sludge disposal efficiency. In addition, the modified activated coke micropowder prepared by carbon source impregnation and microwave modification has better adsorption and affinity for organic matter and activated sludge in sewage, and can form granular sludge faster and better, while improving the sludge removal efficiency of pollutants.

[0062] The preparation steps of starch-impregnated microwave-modified activated coke powder are as follows:

[0063] First, weigh 1.00g of starch and add it to a beaker containing 200mL of deionized water. Apply magnetic stirring for 5 minutes and ultrasonic wave for 5 minutes to evenly distribute the starch in the water. Then, weigh 5.0g of activated char powder (particle size 75-150 microns) and add it to the starch mixture. Apply magnetic stirring for 10 minutes and ultrasonic wave for 10 minutes to ensure that the starch and activated char powder are thoroughly mixed and in full contact.

[0064] The mixed solution was transferred to a round-bottom flask and heated in a microwave chemical reactor at a power of 600-1000 W for 10 minutes. After the mixed solution was naturally cooled to room temperature, the solid powder was collected by high-speed centrifugation and dried in a forced air drying oven at 105°C for 12 hours. The dried sample was sieved to obtain starch-impregnated microwave-modified activated coke micropowder DMACP.

[0065] Example 1

[0066] Take the biological pool of a large urban sewage treatment plant in Zhengzhou (A 2 O) as an example, the number of secondary sedimentation tanks is 4, the diameter is 36m, and the area of ​​each tank is 1017m 2 , the inlet MLSS is 3200 mg / L.

[0067] Secondary sedimentation tank solid surface load Q (kg / (m 2 The calculation formula of h) is:

[0068]

[0069] Where:

[0070] V 进 is the volume flow rate of water in the secondary sedimentation tank, m 3 / h;

[0071] V 回 is the volume flow rate of the secondary sedimentation tank back to the biological pool, m 3 / h;

[0072] C is the sludge concentration in the biological pool, mg / L;

[0073] S is the surface area of ​​the secondary sedimentation tank, m 2 .

[0074] After checking, the maximum surface load of the secondary sedimentation tank of the sewage treatment plant is Q0=4.256kg / (m 2 *h), the designed mud level height of the secondary sedimentation tank is 1m.

[0075] After calculation, TSEI=0.235m 3 *h / kg.

[0076] In this embodiment, H3=4m, H0=1m, H1=1.5m, and H2=H3-H0-H1=1.5m.

[0077] The sludge settling performance is divided into five levels according to TSEI; when SEI≤0.235, the sludge does not swell; when 0.235<SEI≤0.353, the sludge swells slightly; when 0.353<SEI≤0.470, the sludge swells moderately; when 0.470<SEI≤0.588, the sludge swells severely; when SEI>0.588, the sludge swells severely.

[0078] The above-mentioned set levels are applied in actual production to regulate the sedimentation performance of the sludge. After 180 days of continuous monitoring and regulation, the sludge sedimentation performance is good and the effluent is stable.

[0079] Example 2

[0080] Take the biological pool of a large urban sewage treatment plant in Zhengzhou (A 2 Taking O) as an example, the sludge settling performance of the secondary sedimentation tank was evaluated using the traditional SVI and the SEI of the present invention between 2020 and 2023. The specific recorded values ​​are as follows:

[0081] Table 1 Sludge settling performance SVI table

[0082]

[0083] Table 2 Sludge settling performance SEI table

[0084]

[0085] The traditional activated sludge SVI (Survey Viability Index) warning values ​​of 120 mL / g or 150 mL / g, used to assess activated sludge settling performance, have some overlap and similarity with the SEI. However, the SVI has limitations. For example, in February 2020, an SVI of 162 mL / g indicated severe sludge bulking. However, due to the low surface solids loading in the secondary clarifier, the SEI indicated that the sludge level in the secondary clarifier, leading to moderate sludge escape, was low.

[0086] In addition, especially when the SVI is far below or above the design load, there are obvious defects in the actual application of SVI in production; when it is far below the design value, even if the SVI is as high as 200mL / g, the mud level in the secondary sedimentation tank is still at a safe mud level; when it is far above the design value, the SVI is 80mL / g, and the mud level in the secondary sedimentation tank is likely to have affected the effluent water quality.

[0087] In addition, in the calculation of SVI, in order to be as accurate as possible, the tests of MLSS and SV30 mainly rely on manual testing, especially the results of SV30, which are generally measured 1-3 times at fixed times of the day. This method is difficult to meet the current requirements for refined and intelligent management and operation of sewage treatment plants. Through the application of SEI, the sedimentation performance of activated sludge can be continuously monitored, thereby realizing intelligent sludge sedimentation performance control of sewage treatment plants.

[0088] Comparative Example 1

[0089] Take the biological pool of a large urban sewage treatment plant in Zhengzhou (A 2 O) Activated sludge (MLSS=5205mg / L, MLVSS=2928mg / L) was used as the experimental object. The sedimentation performance evaluation experiment was carried out on original activated coke micropowder MACP and starch-impregnated microwave-modified activated coke micropowder DMACP, and a blank control was set up.

[0090] Take 200mL of the mixed liquid from the biological pool effluent and place it in a 250mL beaker. Take three groups and number them. Except for the blank experiment, add 3.0g of original activated coke micropowder MACP and 3.0g of starch-impregnated microwave-modified activated coke micropowder DMACP (determined by the previous small-scale test) to the corresponding numbered beakers in turn. Stir for 5 minutes, quickly introduce into a 100mL graduated cylinder and quickly adjust the volume to 100mL. Place it on a horizontal table and let it stand. Observe and record the sedimentation ratio results of 5min, 15min, and 30min. The test results are shown in Table 1:

[0091] Table 3 Comparison of sedimentation performance of three groups of experiments

[0092]

[0093] It can be seen that in the blank experiment without adding any sludge settling aids, SV30 = 63%, when MACP was added at 1.5 g / L, the corresponding SV30 = 52%, and when DMACP was added at 1.5 g / L, the corresponding SV30 = 42%. Compared with the addition of no substances, the addition of original activated coke micropowder MACP or starch-impregnated microwave-modified activated coke micropowder DMACP can significantly improve the sludge settling performance. The settling ratio of MACP decreased by 17.5%, and the settling ratio of DMACP decreased by 33.3%. The addition of MACP or DMACP can significantly improve the settling performance of activated sludge, and the settling ratio of DMACP decreased by 15.9% more than that of MACP.

[0094] Starch-impregnated microwave-modified activated coke micropowder DMACP is a good method to use it as a sedimentation aid for activated sludge in urban sewage treatment plants; while improving the sedimentation performance of activated sludge, it also significantly increases the calorific value of sludge incineration.

[0095] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A method for evaluating activated sludge settling performance, characterized in that: The following steps are involved: S1. Define the activated sludge settling performance evaluation indicator "sludge escape index" SEI; S11. Determine the mud level height H, m of the secondary sedimentation tank; the solid surface load Q, kg / (m 2 *h); where h is hour; SEI=H / Q, unit is m 3 *h / kg; The physical meaning of the "sludge escape index" is: the actual sludge layer height corresponding to the current solid surface load of the secondary sedimentation tank of a sewage treatment plant under the dynamic hydraulic conditions of continuous water inflow, return flow and discharge; The mud level height is defined as follows: the bottom plane of the effective water depth of the secondary sedimentation tank is used as the reference plane, and the height of the mud surface exceeding the reference plane is defined as the mud level height; S2. Define the threshold value of "sludge escape index" TSEI; S21. Check the maximum mud level H0, m designed for the secondary sedimentation tank; the solid surface load Q0, kg / (m designed for the secondary sedimentation tank). 2 *h); TSEI=H0 / Q0, unit is m 3 *h / kg; S3, compare the "sludge escape index" measured by S1 with the threshold value of the "sludge escape index" defined by S2 to evaluate the settling performance of the activated sludge; When SEI≤TSEI, the sludge does not expand; when TSEI<SEI≤(1+H2 / 3H0)TSEI, the sludge expands slightly; when (1+H2 / 3H0)TSEI<SEI≤(1+2H2 / 3H0)TSEI, the sludge expands moderately; when (1+2H2 / 3H0)TSEI<SEI≤(1+H2 / H0)TSEI, the sludge expands severely; when SEI>(1+H2 / H0)TSEI, the sludge expands severely. Among them, H2=H3-H0-H1; Where, H3 is the effective water depth of the secondary sedimentation tank; H0 is the maximum mud level height designed for the secondary sedimentation tank; and H1 is the mud level protection height of the secondary sedimentation tank.

2. The method for controlling sludge bulking according to the evaluation method of claim 1, characterized in that: When the sludge does not swell, the current process state is maintained without adjustment, and the mud level height and sludge escape index of the secondary sedimentation tank are continuously detected; when the sludge swells slightly, relatively reasonable indicators and parameters are maintained, and the solid surface load of the secondary sedimentation tank is reasonably adjusted according to the mud level height of the secondary sedimentation tank; when the sludge swells moderately, on the basis of the mild swelling treatment measures, a proper amount of micropowder is added through the micropowder adding system to aid sedimentation, and the discharge of residual sludge is appropriately increased to accelerate sludge renewal; when the sludge swells severely, on the basis of the moderate swelling treatment measures, the proportion of micropowder added is appropriately increased, and a proper amount of flocculant is started to be added; when the sludge swells severely, on the basis of the severe swelling treatment measures, the proportion of flocculant added is appropriately increased, and a proper amount of carbon source agent is started to be added to improve the sludge nutritional environment.

3. The method for controlling sludge bulking according to claim 2, characterized in that: The flocculants include PAC and PAM.

4. The method for controlling sludge bulking according to claim 2, wherein: The micro powder adding system mixes the micro powder and water evenly and then transports the micro powder to the adding point.

5. The method for controlling sludge bulking according to claim 2, wherein: The micropowder includes organic microparticles and inorganic microparticles. The organic microparticles are one or more of activated coke powder, waste activated carbon powder, and blue carbon powder. The inorganic microparticles are one or more of bentonite powder, zeolite powder, sludge incineration slag powder, and dried sludge powder.

6. The method for controlling sludge bulking according to claim 5, characterized in that: The particle size of the micro powder is 75-150 microns and the density is 1.1-2.2 g / cm 3 .

7. The method for controlling sludge bulking according to claim 6, characterized in that: The micro powder is activated coke powder.

8. The method for controlling sludge bulking according to claim 7, characterized in that: The activated coke powder is modified. The preparation of the modified activated coke powder comprises the following steps: S1. Adding activated coke powder to a starch solution, stirring and ultrasonically impregnating the activated coke powder to obtain an impregnation mixture; S2, subjecting the S1 impregnation mixture to microwave treatment; S3, separating the solid-liquid mixture after the microwave treatment in S2 and drying it to obtain the modified activated coke powder of the present invention.

9. The method for controlling sludge bulking according to claim 8, characterized in that: The power of the microwave is 600-1000W.

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