Wastewater toxicity grading detection system based on quorum sensing principle and operation and maintenance guidance method

Abstract

The invention discloses a waste water toxicity grading detection system based on the quorum sensing principle and an operation and maintenance guidance method, and belongs to the technical field of environmental biotechnology and waste water treatment monitoring, and the waste water toxicity grading detection system based on the quorum sensing principle comprises a biological sensing module, the biosensor is used for generating specific signal molecules through quorum sensing microbial strains so as to respond to the toxicity of wastewater; the signal detection module is used for detecting the concentration of the specific signal molecules or a corresponding electrochemical signal; and the control and data analysis module is used for controlling reaction conditions, collecting and processing signal data and calculating the toxicity inhibition rate. According to water quality characteristics of different nodes in a wastewater treatment process, different quorum sensing strains are selected, and signal molecules are detected in situ through a high-sensitivity electrochemical sensor, so that rapid, accurate and graded evaluation of toxicity is realized, and further advanced early warning and accurate decision support are provided for system operation and maintenance.

Description

Technical Field

[0001] This invention belongs to the field of environmental biotechnology and wastewater treatment monitoring technology, specifically involving a wastewater toxicity classification detection system based on the principle of quorum sensing and an operation and maintenance guidance method. Background Technology

[0002] Toxicity monitoring of chemical wastewater is crucial for ensuring the stable operation of biological treatment systems. Existing toxicity detection methods (such as luminescent bacteria methods and respiration rate methods) have certain limitations. They mostly reflect overall toxicity and cannot distinguish toxic mechanisms; moreover, they usually use a single bacterial species, making it difficult to address the significant differences in the intensity and properties of wastewater toxicity at different treatment stages. For example, the raw water before treatment may be the most toxic, while the effluent after anaerobic treatment may have reduced toxicity but contain different inhibitory byproducts. Using the same detection bacterial species and standards can lead to inaccurate assessments.

[0003] Quorum sensing (QS) is a mechanism by which microorganisms regulate their gregarious behavior by secreting and sensing specific signaling molecules (such as AHLs and AIPs). The quorum sensing systems of many microorganisms are extremely sensitive to environmental stresses (such as toxic substances). Toxic substances can interfere with the synthesis, release, or recognition of signaling molecules, causing their concentrations to deviate from normal levels. Therefore, changes in the concentration of signaling molecules can serve as a sensitive and specific bioindicator reflecting environmental toxicity.

[0004] This invention utilizes this principle to select different quorum sensing bacteria species based on the water quality characteristics of different nodes in the wastewater treatment process, and uses a highly sensitive electrochemical sensor to detect signal molecules in situ, thereby achieving rapid, accurate, and graded assessment of toxicity, and providing advanced early warning and precise decision support for system operation and maintenance.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a graded detection system and method based on the principle of quorum sensing that can distinguish the toxicity of wastewater at different stages of treatment, and to provide precise operation and maintenance guidance for the biological wastewater treatment system.

[0007] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0008] A wastewater toxicity classification detection system based on the principle of quorum sensing includes:

[0009] The biosensing module is used to generate specific signal molecules through quorum sensing of microbial species in response to wastewater toxicity.

[0010] A signal detection module is used to detect the concentration of the specific signal molecule or the corresponding electrochemical signal;

[0011] The control and data analysis module is used to control reaction conditions, collect and process signal data, and calculate the toxicity inhibition rate.

[0012] The biosensing module is configured with different quorum sensing microbial strains for different process units in the wastewater treatment process to achieve graded assessment of toxicity.

[0013] In one or more embodiments of the present invention, the biosensing module includes at least one set of bioreactors, which contain quorum sensing microbial strains.

[0014] The quorum sensing microbial strains are selected for different wastewater treatment process units, including raw water / high-concentration wastewater detection units, anaerobic influent / effluent detection units, and aerobic influent / effluent detection units.

[0015] In one or more embodiments of the present invention, the raw water / high-concentration wastewater detection unit uses highly resistant quorum sensing bacteria, including Pseudomonas aeruginosa or resistant strains isolated from extreme environments.

[0016] The anaerobic influent / effluent detection unit uses anaerobic quorum sensing bacteria that are sensitive to byproducts of anaerobic environments, including Vibrio fischeri or methanogenic archaea.

[0017] The aerobic inlet / outlet water detection unit uses aerobic quorum sensing bacteria that are sensitive to low concentrations of organic toxins and heavy metals, including Escherichia coli.

[0018] In one or more embodiments of the present invention, the signal detection module is an electrochemical sensor modified with elements capable of specifically recognizing and binding target signal molecules, the elements including aptamers, molecularly imprinted polymers, or specific receptor proteins.

[0019] In one or more embodiments of the present invention, the electrochemical sensor is configured to convert the concentration of signal molecules into an electrical signal, the electrical signal including changes in current or impedance, to achieve in-situ, real-time monitoring.

[0020] In one or more embodiments of the present invention, the control and data analysis module is configured to establish a dose-response relationship model between the baseline concentration of the signaling molecule and the toxicity inhibition rate, and to calculate the toxicity inhibition rate based on the model.

[0021] In one or more embodiments of the present invention, the formula for calculating the toxicity inhibition rate (IR) is as follows:

[0022] IR (%) = |(C-C0)| / C0 × 100%

[0023] Wherein, C0 represents the stable concentration of signal molecules or the corresponding electrical signal value measured under non-toxic baseline conditions, and C represents the concentration of signal molecules or the electrical signal value measured after the water sample to be tested is introduced.

[0024] In one or more embodiments of the present invention, the system is integrated with a wastewater biological treatment system, and the control and data analysis module is also used to output operation and maintenance guidance instructions based on the toxicity inhibition rate, including adjusting the influent flow rate, adding adsorbent, or changing process parameters.

[0025] A wastewater toxicity classification detection and operation and maintenance guidance method based on the principle of quorum sensing includes the following steps:

[0026] S1. The water sample to be tested is introduced into the biosensing module, causing the quorum sensing microorganisms to produce specific signal molecules;

[0027] S2. The concentration of the specific signal molecule or the corresponding electrochemical signal is detected by the signal detection module;

[0028] S3. Process signal data through the control and data analysis module to calculate the toxicity inhibition rate;

[0029] S4. Assess the toxicity level of wastewater based on the toxicity inhibition rate and generate operation and maintenance guidance suggestions.

[0030] In one or more embodiments of the present invention, the method further includes: triggering an alarm system and automatically executing maintenance measures when the toxicity inhibition rate exceeds a preset threshold;

[0031] The operation and maintenance measures include reducing the amount of water entering the aerobic tank, adding powdered activated carbon, or adjusting the anaerobic / aerobic process conditions.

[0032] Compared with existing technologies, the wastewater toxicity classification detection system and operation and maintenance guidance method based on the principle of quorum sensing of the present invention have the following beneficial effects:

[0033] 1) For the first time, differentiated quorum sensing bacterial strains were used to detect the toxicity characteristics and microbial tolerance of different water qualities in the treatment process, resulting in more accurate and instructive evaluation results;

[0034] 2) The quorum sensing mechanism is extremely sensitive to environmental disturbances and can detect low concentrations of specific types of toxic substances, which is more advanced than comprehensive toxicity indicators.

[0035] 3) The electrochemical detection method eliminates the need for complex sample pretreatment, enabling in-situ, real-time, and non-destructive monitoring of signal molecule concentrations with a fast response speed;

[0036] 4) By accurately locating the source of toxicity, it is possible to directly guide maintenance personnel to take the most targeted control measures, which greatly improves maintenance efficiency and system stability. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram illustrating the structure of a wastewater toxicity classification detection system and operation and maintenance guidance method based on the principle of quorum sensing, and its integration with the wastewater treatment process, according to one embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a wastewater toxicity classification detection system based on the principle of quorum sensing, which includes a biosensing module, a signal detection module, and a control and data analysis module.

[0041] The biosensing module is constructed by setting up three bioreactors, forming three independent detection units, each targeting the water quality characteristics of different process nodes:

[0042] Raw water / high-concentration wastewater detection unit (located at the outlet of the equalization tank): *Pseudomonas aeruginosa* PAO1 was selected as a quorum-sensing strain with extremely high toxicity resistance. This strain is a common model organism; its LasI / R system relies on N-(3-oxododecanoyl)homoserine lactone (3-oxo-C12-HSL) for quorum sensing, exhibiting strong tolerance to various industrial toxins and producing detectable changes in signal molecules under such stress. Then, *Pseudomonas aeruginosa* in the logarithmic growth phase was immobilized using a sodium alginate-calcium chloride encapsulation method to form gel microspheres with a particle size of approximately 3 mm, which were then filled into the bioreactor. This method maintains bacterial activity and allows the signal molecules to diffuse freely.

[0043] Anaerobic influent / effluent monitoring unit (located at the inlet of the UASB anaerobic reactor): *Vibrio fischeri* was selected as the strain sensitive to anaerobic byproducts. This bacterium is an internationally standardized toxicity test strain; its quorum sensing system relies on N-hexanoyl homoserine lactone and it is highly sensitive to anaerobic metabolic byproducts such as volatile fatty acids and sulfides. It was also immobilized using sodium alginate encapsulation. The reactor is equipped with a light-shielding hood, and the internal environment is maintained at a micro-aerobic to anaerobic level by filling with nitrogen gas, with the temperature controlled at 25°C to simulate its optimal habitat.

[0044] Aerobic influent / effluent detection unit (located at the inlet of the A / O aerobic tank): *Escherichia coli* MG1655 was selected as the aerobic quorum sensing strain sensitive to low concentrations of organic toxins and heavy metals. This strain's SdiA system can sense various AHL signals, and its metabolic activity is highly sensitive to low doses of acrylonitrile, phenol, and heavy metal ions. It was also immobilized using sodium alginate encapsulation. Sterile air was continuously introduced into the reactor to maintain dissolved oxygen >2 mg / L, and the temperature was controlled at 37℃.

[0045] When constructing the signal detection module, a dedicated electrochemical sensor is configured for each detection unit to detect its corresponding specific signal molecule.

[0046] The electrochemical sensor uses a glassy carbon electrode as the working electrode. Molecularly imprinted polymers (MIPs) are employed as specific recognition elements. Using 3-oxo-C12-HSL (targeting *Pseudomonas aeruginosa*), C6-HSL (targeting *Vibrio fischeri*), and C8-HSL (targeting a common AHL-inducing bacillus in *Escherichia coli*) as template molecules, corresponding MIPs were synthesized and modified onto the surface of their respective working electrodes. The MIPs can capture target signal molecules with high selectivity and high affinity.

[0047] Differential pulse voltammetry is used for detection. When the signal molecules are captured by MIPs, redox reactions occur at specific potentials, generating electrical current signals. There is a linear relationship between the concentration of signal molecules and the current response value within a certain range. The sensor is directly immersed in the effluent of the bioreactor to achieve in-situ and real-time monitoring, with a response time within 5 minutes.

[0048] The control and data analysis module consists of a PLC controller, a data acquisition card, and upper computer analysis software. The PLC controller controls the water sample injection pump, the reactor temperature, and the pH of each detection unit. The data acquisition card continuously collects the current signals of each electrochemical sensor.

[0049] The system first uses a non-toxic synthetic culture medium as the reference water sample, which flows through each detection unit and operates continuously for 24 hours. The stable average electrical signal value at this time is recorded as the reference signal value (C0) of this unit. After introducing the water sample to be tested, the software takes the average signal value within a monitoring period as the measured signal value (C).

[0050] According to the preset formula, the toxicity inhibition rate (IR) is automatically calculated:

[0051] IR(%) = |(C - C0)| / C0 × 100%

[0052] This formula can cover both cases where toxic substances inhibit the synthesis of signal molecules (C < C0) and the stress-induced abnormal increase (C > C0).

[0053] The upper computer analysis software pre-stores dose-effect relationship models for different typical poisons. For example, for the aerobic unit, through previous experiments, a standard curve of acrylonitrile concentration and IR value was established, such as the S-shaped Logistic model. When the IR value is measured, the model can inversely estimate the equivalent toxicity concentration and conduct early warning grading. If IR < 20% is a mild early warning, 20% ≤ IR < 40% is a moderate early warning, and IR ≥ 40% is a severe early warning.

[0054] A method for wastewater toxicity grading detection and operation and maintenance guidance based on the principle of quorum sensing includes the following steps:

[0055] S1. Introduce the water sample to be tested into the biological sensing module to enable quorum sensing microbial strains to generate specific signal molecules;

[0056] S2. Detect the concentration of the specific signal molecules or the corresponding electrochemical signals through the signal detection module;

[0057] S3. Process the signal data through the control and data analysis module to calculate the toxicity inhibition rate;

[0058] S4. Evaluate the wastewater toxicity level based on the toxicity inhibition rate and generate operation and maintenance guidance suggestions;

[0059] S5. When the toxicity inhibition rate exceeds the preset threshold, the alarm system is triggered and maintenance measures are automatically executed.

[0060] Operational and maintenance measures include immediately reducing the amount of water entering the aerobic tank to reduce the impact of toxic load; adding powdered activated carbon to the aerobic tank to quickly remove trace amounts of organic toxins from the water through adsorption; and suggesting a thorough investigation of the UASB reactor's operating status, as incomplete metabolic products may be present.

[0061] Subsequent laboratory tests confirmed a slight increase in acrylonitrile concentration in the anaerobic effluent, which strongly inhibits aerobic bacteria but has little impact on anaerobic bacteria. Due to the timely response, an aerobic tank collapse was averted.

[0062] To verify the effectiveness of this invention, we conducted laboratory simulation tests and field trials, and compared it with traditional toxicity testing methods.

[0063] I. Laboratory Simulation Experiment: Dose-Response Relationship and Sensitivity Verification

[0064] Experimental objective: To verify the response sensitivity of different detection units to target characteristic pollutants.

[0065] Materials and Methods:

[0066] Testing system: The three-unit testing system constructed as described above.

[0067] Target poison:

[0068] Aerobic unit (E. coli): Acrylonitrile (representing cyanide-containing organic compounds)

[0069] Anaerobic unit (Vibrio fischeri): valerate (representing a high concentration of volatile fatty acids)

[0070] Raw water unit (Pseudomonas aeruginosa): Phenol (representing a high concentration of a complex toxic substance)

[0071] Method: Simulated wastewater containing target toxins of different concentration gradients was introduced into each unit, and the changes in electrochemical signals were recorded to calculate the toxicity inhibition rate (IR).

[0072] Table 1: Dose-effect relationship data of each detection unit for different toxic substances

[0073]

[0074]

[0075] Note: IR > 80% indicates that microbial activity is completely inhibited.

[0076] The data clearly demonstrate that each detection unit exhibits the highest sensitivity to its target toxicant. For example, a low concentration of 2.0 mg / L acrylonitrile can cause a strong inhibition of 45.5% in the aerobic unit, while having minimal effect (IR <13%) on the anaerobic and raw water units. This fully demonstrates the ability of this invention to distinguish between the mechanism and source of toxicity.

[0077] The aerobic unit has a detection limit of 0.5 mg / L for acrylonitrile and can produce a significant signal change of 15.2%, which is much higher than the usual sensing threshold of the traditional activated sludge process, about 5-10 mg / L, demonstrating its potential for early warning.

[0078] II. Comparative Experiment with Traditional Methods

[0079] Experimental objective: To compare the response performance and information richness of this invention with the national standard method - luminescent bacteria method GB / T15441 under simulated complex toxicity impact scenarios.

[0080] Scenario setting: Simulate an anaerobic reactor malfunction, with the effluent containing trace amounts of acrylonitrile (2.0 mg / L) and a high concentration of valeric acid (200 mg / L), resulting in a mixture of toxicity.

[0081] Table 2: Comparison of responses of different detection methods under mixed toxicity shocks

[0082]

[0083] The electrochemical detection method of this invention enables in-situ, real-time monitoring, with a response speed of 8 minutes, which is much faster than the 30-minute response time of the luminescent bacteria method, which requires a long incubation period, thus saving valuable time for operation and maintenance.

[0084] The IR value differences between the units provided by this invention can directly pinpoint the toxicity originating from beyond the anaerobic stage and indicate mixed toxicity. In contrast, the luminescent bacteria method only provides a general "comprehensive toxicity" index, which cannot guide subsequent specific operational and maintenance actions.

[0085] III. On-site pilot verification and operation and maintenance guidance effectiveness

[0086] Location and period: Wastewater treatment plant in a fine chemical industrial park, continuous monitoring for 3 months.

[0087] Key event log:

[0088] During a single operation, the system recorded the following sequence of events:

[0089] At time T0: The IR value of the aerobic unit jumps from 15% to 52% within 5 minutes, triggering a "severe alarm".

[0090] T0+1 minutes: The system automatically diagnoses: the raw water unit (IR=12%) and the anaerobic unit (IR=18%) are normal, confirming that the toxicity originates from the anaerobic stage and has a specific and strong inhibitory effect on aerobic microorganisms.

[0091] T0+2 minutes: The system automatically executes the preset plan: reduces the influent flow rate of the aerobic tank by 60% and starts the powdered activated carbon (PAC) dosing device.

[0092] T0+30 minutes: The IR value of the aerobic unit drops to 35%, and the system alarm is downgraded to "moderate".

[0093] T0+2 hours: The IR value of the aerobic unit returned to the background level, approximately 15%. Subsequent GC-MS analysis confirmed that the acrylonitrile concentration in the UASB effluent instantaneously increased to 4.8 mg / L.

[0094] In this incident, thanks to the rapid, accurate diagnosis and automatic response of the system invented in this invention, a potential sludge bulking and collapse accident in the aerobic tank caused by an acrylonitrile shock was successfully avoided. Traditional methods relying on manual testing are completely inadequate to handle such sudden shocks.

[0095] This case study fully demonstrates the closed-loop intelligent operation and maintenance process from detection and diagnosis to decision execution, and fully proves how the present invention can transform toxicity monitoring information into direct and effective operation and maintenance productivity.

[0096] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0097] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wastewater toxicity classification and detection system based on the principle of quorum sensing, characterized in that, include: The biosensing module is used to generate specific signal molecules through quorum sensing of microbial species in response to wastewater toxicity. A signal detection module is used to detect the concentration of the specific signal molecule or the corresponding electrochemical signal; The control and data analysis module is used to control reaction conditions, collect and process signal data, and calculate the toxicity inhibition rate. The biosensing module is configured with different quorum sensing microbial strains for different process units in the wastewater treatment process to achieve graded assessment of toxicity.

2. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 1, characterized in that, The biosensing module includes at least one set of bioreactors, which contain immobilized quorum sensing microbial strains. The quorum sensing microbial strains are selected for different wastewater treatment process units, including raw water / high-concentration wastewater detection units, anaerobic influent / effluent detection units, and aerobic influent / effluent detection units.

3. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 2, characterized in that, The raw water / high-concentration wastewater detection unit uses highly resistant quorum sensing bacteria, including Pseudomonas aeruginosa or resistant strains isolated from extreme environments. The anaerobic influent / effluent detection unit uses anaerobic quorum sensing bacteria that are sensitive to byproducts of anaerobic environments, including Vibrio fischeri or methanogenic archaea. The aerobic inlet / outlet water detection unit uses aerobic quorum sensing bacteria that are sensitive to low concentrations of organic toxins and heavy metals, including Escherichia coli.

4. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 1, characterized in that, The signal detection module is an electrochemical sensor modified with elements capable of specifically recognizing and binding target signal molecules, including aptamers, molecularly imprinted polymers, or specific receptor proteins.

5. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 4, characterized in that, The electrochemical sensor is configured to convert the concentration of signal molecules into an electrical signal, which includes changes in current or impedance, enabling in-situ, real-time monitoring.

6. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 1, characterized in that, The control and data analysis module is configured to establish a dose-response relationship model between the baseline concentration of the signaling molecule and the toxicity inhibition rate, and to calculate the toxicity inhibition rate based on the model.

7. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 6, characterized in that, The formula for calculating the toxicity inhibition rate (IR) is as follows: IR (%) = |(C-C0)| / C0 × 100% Wherein, C0 represents the stable concentration of signal molecules or the corresponding electrical signal value measured under non-toxic baseline conditions, and C represents the concentration of signal molecules or the electrical signal value measured after the water sample to be tested is introduced.

8. The wastewater toxicity classification and detection system based on the quorum sensing principle according to claim 1, characterized in that, The system is integrated with the wastewater biological treatment system. The control and data analysis module is also used to output operation and maintenance guidance instructions based on the toxicity inhibition rate, including adjusting the influent flow rate, adding adsorbent, or changing process parameters.

9. A method for wastewater toxicity classification detection and operation and maintenance guidance based on the principle of quorum sensing, characterized in that, Using the wastewater toxicity classification detection system according to any one of claims 1-8, the method includes the following steps: S1. The water sample to be tested is introduced into the biosensing module, causing the quorum sensing microorganisms to produce specific signal molecules; S2. The concentration of the specific signal molecule or the corresponding electrochemical signal is detected by the signal detection module; S3. Process signal data through the control and data analysis module to calculate the toxicity inhibition rate; S4. Assess the toxicity level of wastewater based on the toxicity inhibition rate and generate operation and maintenance guidance suggestions.

10. The method according to claim 9, characterized in that, The method further includes: triggering an alarm system and automatically implementing maintenance measures when the toxicity inhibition rate exceeds a preset threshold; The operation and maintenance measures include reducing the amount of water entering the aerobic tank, adding powdered activated carbon, or adjusting the anaerobic / aerobic process conditions.

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