Sludge bulking control method applied to sewage treatment

Abstract

The invention discloses a sludge bulking control method applied to sewage treatment, and relates to the technical field of sewage treatment. The method comprises the following steps: adjusting the working mode of the plate-and-frame filter press; polyacrylamide (PAM) anions or polyaluminum ferric chloride (PAFC) are added into the effluent of the biochemical tank to assist in improving the solid-liquid separation effect of the secondary sedimentation tank, and the PAM anions are preferentially selected; the method comprises the following steps: collecting biochemical pool water samples for many times every day, determining the cause of sludge settleability reduction through microscopic examination, and judging whether the sludge settleability is caused by filamentous bacterium expansion; for the sludge settleability problem which is difficult to control by a conventional means, a biological targeting settling aid can be considered to be used; and the sludge performance of the biochemical pool is optimized by adding a specific strain into the aerobic pool. According to the method, biochemical pool water samples are collected for multiple times every day, the reason of sludge sedimentation performance reduction is determined through microscopic examination, whether the sludge is caused by filamentous bacterium expansion or not is judged, the problem of sludge expansion can be found and prevented in the early stage, and the early warning capacity of the system is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sludge bulking control method applied to sewage treatment. Background Art

[0002] Sewage treatment is an important and indispensable municipal engineering project in cities and rural areas. It is of great significance to protect the environment, safeguard people's health and promote sustainable development. The main task of municipal sewage treatment plants is to treat domestic sewage and industrial wastewater, remove harmful substances in them, make them meet the discharge standards, and prevent water pollution. At present, municipal sewage treatment plants widely use activated sludge method for sewage treatment. The activated sludge method is a biological treatment method that uses microorganisms to degrade organic matter in sewage. It mainly includes the following parts: the primary sedimentation tank initially removes suspended solids and large particle impurities in the sewage, and the biochemical tank removes the chemical oxygen demand (COD cr ), five-day biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), total nitrogen (TN) and total phosphorus (TP) and other pollutants. The secondary sedimentation tank separates the activated sludge in the biochemical pool and the treated clean water through gravity sedimentation to further improve the effluent quality; the sludge treatment system concentrates, dehydrates and disposes of the residual sludge produced in the biochemical pool.

[0003] Although the activated sludge process has achieved remarkable results in sewage treatment, there are also some common problems, among which sludge bulking is an important problem. Sludge bulking refers to the decline in the settling performance of activated sludge due to certain reasons, which makes it impossible to effectively separate the sludge in the secondary sedimentation tank, thus affecting the effluent water quality and treatment efficiency. There are two main types of sludge bulking: non-filamentous bacterial bulking, which is caused by the decline in sludge settling performance due to factors such as nutrient imbalance, temperature changes, and pH fluctuations; filamentous bacterial bulking, which is caused by the excessive growth of filamentous bacteria, forming loose flocs, resulting in the deterioration of sludge settling performance.

[0004] To this end, we provide a sludge bulking control method for sewage treatment to solve the above-mentioned problems. Summary of the invention

[0005] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] The present invention is a sludge bulking control method applied to sewage treatment, comprising the following steps:

[0007] S100, adjust the working mode of the plate and frame filter press: expand the volume of the sludge storage tank to reduce the time required for sludge settling in the intermediate sludge storage tank and the time of the material discharge rate, so that the moisture content of the residual sludge in the biochemical stage is reduced to about 97%. Arrange the plate and frame filter press to work 24 hours a day to further reduce the sludge concentration in the biochemical tank;

[0008] S200, adding reagents: adding polyacrylamide (PAM) anions or polyaluminium ferric chloride (PAFC) to the effluent of the biochemical pool to assist in improving the solid-liquid separation effect of the secondary sedimentation tank. PAM anions are preferred because they are more economical than PAFC.

[0009] S300, Monitoring and Analysis: Collect water samples from the biochemical pool several times a day and use microscope examination to determine the cause of the decline in sludge settling performance and whether it is caused by filamentous bacterial expansion;

[0010] S400, Use of biological targeted settling aids: For sludge settling problems that are difficult to control by conventional means, biological targeted settling aids can be considered. The agent must meet the requirements of being non-toxic, fast-acting, and not having a negative impact on the activity of microorganisms in the sludge. The recommended dosage is at least 3 grams per kiloliter of water, and can be adjusted according to actual conditions;

[0011] S500, Optimize bacterial strain addition: Optimize the performance of biochemical pool sludge by adding specific bacterial strains to the aerobic pool.

[0012] The present invention is further configured that the step S100 further includes:

[0013] S101. Clean the filter plates and filter cloth of the plate and frame filter press regularly to maintain good filtering performance;

[0014] S102. According to the change of sludge concentration in the biochemical pool, the operation time and frequency of the plate and frame filter press are dynamically adjusted to keep the sludge concentration within the optimal range.

[0015] The present invention is further configured such that the step of adding PAM anions or PAFC in step S200 needs to be preceded by a small test to determine the optimal dosage and frequency of addition to ensure the effectiveness and economy of the agent.

[0016] The present invention is further configured such that step S300 also includes recording the time and location of each water sample collection, and inputting the data into a computer system for analysis, so as to timely discover the changing trend of sludge settling performance.

[0017] The present invention is further configured that step S300 further includes:

[0018] S301. When the sludge settling performance is reduced due to non-filamentous bacteria, the internal environment of the biochemical pool is adjusted, such as changing the working state of the internal return pump and adopting a multi-stage water distribution strategy, to promote the healthy cultivation of the sludge in the biochemical pool;

[0019] S302. If filamentous bacteria expansion is detected, add an appropriate amount of sodium hypochlorite to the effluent of the anoxic section while ensuring normal dissolved oxygen in the aerobic section, control the residual chlorine content in the supernatant at around 0.1 mg / L, and closely monitor changes in microbial activity. If any abnormality is found, stop adding sodium hypochlorite immediately.

[0020] The present invention is further configured such that step S301 also includes dynamically adjusting the aeration volume and aeration time according to changes in the dissolved oxygen concentration in the biochemical pool to maintain a suitable biochemical environment.

[0021] The present invention is further configured such that step S302 further includes, after adding sodium hypochlorite, regularly collecting water samples for microbial microscopic examination, monitoring changes in the number of filamentous bacteria, and adjusting the amount of sodium hypochlorite added according to the changes.

[0022] The present invention is further configured such that step S400 also includes conducting a small laboratory test before adding to evaluate the sedimentation-aiding effect at different concentrations and selecting the most suitable addition concentration for practical application.

[0023] The present invention is further configured such that step S500 also includes analyzing the microbial community in the biochemical pool before adding the bacterial strains, selecting bacterial strains with good compatibility with existing microorganisms for addition, and regularly monitoring the survival rate and activity of the bacterial strains after the addition.

[0024] The present invention has the following beneficial effects:

[0025] 1. The present invention reduces the water content of the residual sludge in the biochemical stage to about 97% by expanding the capacity of the sludge storage tank and reducing the time required for sludge settling in the intermediate sludge storage tank and the time of the material discharge rate. This not only improves the working efficiency of the plate and frame filter press, but also reduces the time and cost of sludge treatment. The plate and frame filter press is arranged to work 24 hours a day, further reducing the sludge concentration in the biochemical tank, creating favorable conditions for increasing the sewage treatment load. This enables the sewage treatment system to better cope with peak loads and improve the overall treatment capacity.

[0026] 2. The present invention effectively improves the solid-liquid separation effect of the secondary sedimentation tank and improves the effluent water quality by adding PAM anions or PAFC to the effluent of the biochemical pool. A small test is conducted before adding to determine the optimal dosage and frequency of addition to ensure the effectiveness and economy of the agent. This avoids excessive use of the agent and reduces operating costs.

[0027] 3. The present invention collects water samples from the biochemical pool several times a day, and determines the cause of the decline in sludge settling performance through microscopic examination to determine whether it is caused by filamentous bacteria expansion, which is helpful for early detection and prevention of sludge expansion problems and improves the early warning ability of the system; when the decline in sludge settling performance caused by non-filamentous bacteria is detected, the internal environment of the biochemical pool is adjusted, such as changing the working state of the internal reflux pump and adopting a multi-stage water distribution strategy, to promote the healthy cultivation of biochemical pool sludge; if filamentous bacteria expansion is detected, then on the premise of ensuring normal dissolved oxygen in the aerobic section, an appropriate amount of sodium hypochlorite is added to the effluent of the anoxic section to control the residual chlorine content in the supernatant to about 0.1 mg / L.

[0028] 4. The present invention optimizes the sludge performance of the biochemical pool by adding specific strains to the aerobic pool. Before adding the strains, the microbial community in the biochemical pool is analyzed, and strains with good compatibility with existing microorganisms are selected for addition. This helps to improve the treatment efficiency and stability of the system.

[0029] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example

[0032] The present invention is a sludge bulking control method applied to sewage treatment, comprising the following steps:

[0033] Step S100: Adjust the working mode of the plate and frame filter press and expand the volume of the sludge storage tank to reduce the time required for sludge sedimentation in the intermediate sludge storage tank and the time of the material discharge rate, so that the moisture content of the residual sludge in the biochemical stage is reduced to about 97%, and arrange the plate and frame filter press to work 24 hours a day to further reduce the sludge concentration in the biochemical tank.

[0034] Specific measures: Expand the volume of the sludge storage tank by adding partition walls or increasing the depth on the basis of the existing sludge storage tank, or increase the overall capacity by building additional sludge storage tanks. This can reduce the sedimentation and material discharge time of the intermediate sludge storage tank, reduce the moisture content of the residual sludge in the biochemical stage to about 97%, help improve the sludge concentration effect, reduce the time and cost of sludge treatment, ensure that the plate and frame filter press operates around the clock and treats sludge uninterruptedly, further reduce the sludge concentration in the biochemical tank, create favorable conditions for increasing the sewage treatment load, and significantly improve the system's treatment capacity, especially during peak load periods.

[0035] S101: Clean the filter plates and filter cloth of the plate and frame filter press regularly to maintain its good filtering performance.

[0036] Specific measures: Develop a regular cleaning plan, use a high-pressure water gun or other cleaning tools to thoroughly clean the filter plate and filter cloth to ensure good filtration performance of the plate and frame filter press, prevent clogging and reduce filtration efficiency. Regular cleaning can extend the service life of the equipment and reduce maintenance costs.

[0037] S102: According to the change of sludge concentration in the biochemical pool, the operation time and frequency of the plate and frame filter press are dynamically adjusted to keep the sludge concentration within the optimal range.

[0038] Specific measures: Use the monitoring system to monitor the changes in the sludge concentration in the biochemical pool in real time, and dynamically adjust the operating time and frequency of the plate and frame filter press as needed to ensure that the sludge concentration is within the optimal range, avoid system overload or underload, and maintain stable operation of the system. Dynamic adjustment helps to optimize the treatment effect and improve the flexibility and adaptability of the system.

[0039] Step S200: Adding reagents, adding polyacrylamide (PAM) anions or polyaluminium ferric chloride (PAFC) to the effluent of the biochemical pool to assist in improving the solid-liquid separation effect of the secondary sedimentation tank. PAM anions are preferred because they are more economical than PAFC. The step of adding PAM anions or PAFC requires a small test before adding to determine the optimal dosage and frequency of addition to ensure the effectiveness and economy of the reagents.

[0040] Specific measures: According to the results of laboratory pilot experiments, choose PAM anions or PAFC for addition, and give priority to PAM anions because they are more economical and show higher efficiency in practical applications. Under laboratory conditions, determine the optimal dosage and frequency of PAM anions or PAFC through pilot experiments to ensure the effectiveness and economy of the agent and avoid excessive use and waste. Pilot experiments can provide scientific basis to ensure the rationality and economy of the use of agents.

[0041] Step S300: Collect water samples from the biochemical pool several times a day, and determine the cause of the decline in sludge settling performance through microscopic examination to determine whether it is caused by filamentous bacteria expansion.

[0042] Specific measures: Develop a plan to collect water samples multiple times a day, and use standard sampling bottles and samplers to collect water samples from biochemical pools. Multiple daily collections can promptly detect changes in sludge settling performance and provide timely data support for subsequent treatment; examine water samples through a microscope to determine the cause of the decline in sludge settling performance and whether it is caused by filamentous bacteria expansion; microscopic examination can intuitively observe the types and quantities of microorganisms in the sludge, helping to accurately diagnose problems.

[0043] S301: When it is detected that the sludge settling performance has decreased due to non-filamentous bacteria, the internal environment of the biochemical pool is adjusted, such as changing the working state of the internal recirculation pump and adopting a multi-stage water distribution strategy to promote the healthy cultivation of the sludge in the biochemical pool. According to the changes in the dissolved oxygen concentration in the biochemical pool, the aeration volume and aeration time are dynamically adjusted to maintain a suitable biochemical environment.

[0044] Specific measures: Adjust the working state of the internal return pump: According to the changes in the sludge settling performance, adjust the working state of the internal return pump, increase or decrease the return volume to improve the sludge settling performance. The adjustment of the internal return pump can optimize the flow state of the sludge and promote the coagulation of the sludge; through the multi-stage water distribution strategy, optimize the water flow distribution in the biochemical pool and promote the healthy cultivation of sludge. Multi-stage water distribution can ensure the uniform distribution of sewage in the biochemical pool and improve the treatment effect; according to the changes in the dissolved oxygen concentration in the biochemical pool, adjust the aeration volume and aeration time in real time through the monitoring system to maintain a suitable biochemical environment and ensure the normal growth and metabolism of microorganisms. Dynamic adjustment of aeration can improve oxygen utilization and reduce energy consumption.

[0045] S302: If filamentous bacteria expansion is detected, then under the premise of ensuring normal dissolved oxygen in the aerobic section, add an appropriate amount of sodium hypochlorite to the effluent of the anoxic section to control the residual chlorine content in the supernatant at around 0.1 mg / L. At the same time, closely monitor the changes in microbial activity. Once abnormalities are found, stop adding sodium hypochlorite immediately. After adding sodium hypochlorite, collect water samples regularly for microbial microbial microscopic examination, monitor changes in the number of filamentous bacteria, and adjust the amount of sodium hypochlorite added according to the changes.

[0046] Specific measures: When filamentous bacteria expansion is detected, add an appropriate amount of sodium hypochlorite to the effluent of the anoxic section to control the residual chlorine content in the supernatant to about 0.1 mg / L; sodium hypochlorite can effectively inhibit the growth of filamentous bacteria, but the dosage must be strictly controlled to avoid negative effects on other beneficial microorganisms; after adding sodium hypochlorite, regularly collect water samples for microbial microscopic examination to monitor the changes in the number of filamentous bacteria. Once abnormal microbial activity is found, the addition of sodium hypochlorite should be stopped immediately. Regular monitoring can adjust the treatment measures in time to ensure the safety and stability of the system; according to the changes in the number of filamentous bacteria, dynamically adjust the dosage of sodium hypochlorite to ensure the effectiveness and safety of the control measures. Dynamic adjustment can improve the control accuracy and avoid excessive use of agents.

[0047] Further: record the time and location of each water sample collection, and input the data into the computer system for analysis, so as to timely discover the changing trend of sludge settling performance.

[0048] Specific measures: Record the time and location of each water sample collection in detail, and input the data into the computer system for analysis to promptly discover the changing trend of sludge settling performance; data recording and analysis can provide a scientific basis to help managers take timely measures to improve the management level of the system.

[0049] Step S400: For sludge settling problems that are difficult to control by conventional means, the use of biological targeted settling aids can be considered. The agent must meet the requirements of being non-toxic, fast-response, and not having a negative impact on the activity of microorganisms in the sludge. The recommended dosage is at least 3 grams per 1,000 liters of water, and it should be adjusted according to actual conditions. Before adding, a small laboratory test should be conducted to evaluate the settling aid effect at different concentrations, and the most suitable addition concentration should be selected for actual application.

[0050] Specific measures: Select biological targeted settling aids that are non-toxic, fast-reacting, and do not negatively affect the activity of microorganisms in sludge. The selection of settling aids should be based on laboratory research to ensure their safety and effectiveness. Laboratory tests should be conducted before addition to evaluate the settling effect at different concentrations and select the most appropriate addition concentration for practical application. Laboratory tests can provide a scientific basis to ensure the efficiency and economy of the settling aids.

[0051] Step S500: Optimize the sludge performance of the biochemical pool by adding specific strains of bacteria to the aerobic pool. Before adding the strains, analyze the microbial community in the biochemical pool, select strains that are compatible with existing microorganisms for addition, and regularly monitor the survival rate and activity of the strains after addition.

[0052] Specific measures: Before adding bacteria, analyze the microbial community in the biochemical pool and select bacteria that are compatible with existing microorganisms for addition; the selection of bacteria should be based on laboratory research to ensure its synergistic effect with existing microorganisms. After adding bacteria, collect water samples regularly for microbial microscopic examination to monitor the survival rate and activity of the bacteria to ensure the effectiveness and long-term stability of the bacteria and maintain the microbial balance in the biochemical pool; regular monitoring can adjust treatment measures in a timely manner and improve the treatment effect of the system.

[0053] The above method realizes effective control of sludge bulking, improves sewage treatment efficiency and effluent water quality, and reduces operating costs.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0055] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A sludge bulking control method for sewage treatment, characterized in that: The following steps are involved: S100, adjust the working mode of the plate and frame filter press: expand the volume of the sludge storage tank to reduce the time required for sludge settling in the intermediate sludge storage tank and the time of the material discharge rate, so that the moisture content of the residual sludge in the biochemical stage is reduced to about 97%, and arrange the plate and frame filter press to work 24 hours a day to further reduce the sludge concentration in the biochemical tank; S200, adding reagents: adding polyacrylamide (PAM) anions or polyaluminium ferric chloride (PAFC) to the effluent of the biochemical pool to assist in improving the solid-liquid separation effect of the secondary sedimentation tank. PAM anions are preferred because they are more economical than PAFC. S300, Monitoring and Analysis: Collect water samples from the biochemical pool several times a day and use microscope examination to determine the cause of the decline in sludge settling performance and whether it is caused by filamentous bacterial expansion; S400, Use of biological targeted settling aids: For sludge settling problems that are difficult to control by conventional means, biological targeted settling aids can be considered. The agent must meet the requirements of being non-toxic, fast-acting, and not having a negative impact on the activity of microorganisms in the sludge. The recommended dosage is at least 3 grams per kiloliter of water, and can be adjusted according to actual conditions; S500, Optimize bacterial strain addition: Optimize the performance of biochemical pool sludge by adding specific bacterial strains to the aerobic pool.

2. A sludge bulking control method for sewage treatment according to claim 1, characterized in that: The step S100 also includes: S101. Clean the filter plates and filter cloth of the plate and frame filter press regularly to maintain good filtering performance; S102. According to the change of sludge concentration in the biochemical pool, the operation time and frequency of the plate and frame filter press are dynamically adjusted to keep the sludge concentration within the optimal range.

3. A sludge bulking control method for sewage treatment according to claim 1, characterized in that: The step of adding PAM anions or PAFC in step S200 needs to be tested in a small scale before adding to determine the optimal dosage and frequency of addition to ensure the effectiveness and economy of the agent.

4. The sludge bulking control method for sewage treatment according to claim 1, characterized in that: The step S300 also includes recording the time and location of each water sample collection, and inputting the data into a computer system for analysis, so as to timely discover the changing trend of sludge settling performance.

5. The sludge bulking control method for sewage treatment according to claim 1, characterized in that: The step S300 further includes: S301. When the sludge settling performance is reduced due to non-filamentous bacteria, the internal environment of the biochemical pool is adjusted, such as changing the working state of the internal return pump and adopting a multi-stage water distribution strategy, to promote the healthy cultivation of the sludge in the biochemical pool; S302. If filamentous bacteria expansion is detected, add an appropriate amount of sodium hypochlorite to the effluent of the anoxic section while ensuring normal dissolved oxygen in the aerobic section, control the residual chlorine content in the supernatant at around 0.1 mg / L, and closely monitor changes in microbial activity. If any abnormality is found, stop adding sodium hypochlorite immediately.

6. A sludge bulking control method for sewage treatment according to claim 5, characterized in that: The step S301 also includes dynamically adjusting the aeration volume and aeration time according to the change of dissolved oxygen concentration in the biochemical pool to maintain a suitable biochemical environment.

7. A sludge bulking control method for sewage treatment according to claim 5, characterized in that: The step S302 also includes periodically collecting water samples for microbial microscopic examination after adding sodium hypochlorite, monitoring the change in the number of filamentous bacteria, and adjusting the amount of sodium hypochlorite added according to the change.

8. The sludge bulking control method for sewage treatment according to claim 1, characterized in that: The step S400 also includes conducting a small laboratory test before adding to evaluate the sedimentation-aiding effect at different concentrations and selecting the most suitable addition concentration for practical application.

9. The sludge bulking control method for sewage treatment according to claim 1, characterized in that: The step S500 also includes analyzing the microbial community in the biochemical pool before adding the bacterial strains, selecting bacterial strains with good compatibility with existing microorganisms for addition, and regularly monitoring the survival rate and activity of the bacterial strains after the addition.