A control system and control method for improving the carbon capture efficiency of an enhanced contact stability process

Abstract

The application discloses a control system and method for improving carbon capture efficiency of a contact stabilization process, the control system comprising a first electromagnetic flowmeter installed on an influent pipe of a contact stabilization process unit, a variable frequency sludge discharge pump and a second electromagnetic flowmeter installed on a sludge discharge pipe, an oxygen consumption rate detector and a sludge concentration detector installed in a contact tank and a stabilization tank, a suspended substance detector installed on an effluent pipe, and a data acquisition and control module. The method comprises the following steps: the data acquisition and control module calculates sludge discharge of the contact stabilization process unit according to a set control algorithm, in combination with real-time detection data of the oxygen consumption rate, the sludge concentration, influent flow and effluent suspended substance, and then outputs a signal to adjust the frequency of the sludge discharge pump, so that the sludge discharge reaches the calculated value, and finally the purpose of dynamically regulating biological activity and biological flocculation performance is achieved. The method can greatly improve the capture efficiency of the contact stabilization process on organic matters in sewage and the process operation stability.

Description

Technical Field

[0001] This invention relates to a wastewater treatment and resource recovery control system and its control method, and more particularly to a control system and control method for improving the carbon capture efficiency of a contact stabilization process. Background Technology

[0002] For a long time, wastewater treatment has mainly relied on the aerobic "adsorption-degradation" process of microorganisms to mineralize and decompose organic pollutants. This process is energy-intensive, produces large amounts of carbon, and has a low resource and energy recovery rate. In fact, wastewater is an overlooked energy carrier. For typical domestic wastewater with a COD concentration of 500 mg / L, the organic chemical energy contained can reach 1.93 kWh / m³. 3 If this chemical energy is recovered and utilized, low-carbon operation and even energy self-sufficiency of sewage treatment plants can be achieved. The key to achieving this goal is to recover carbon resources from sewage.

[0003] Enriching and separating organic matter from wastewater is a prerequisite for carbon resource recovery and utilization. Among these technologies, the efficient contact stabilization process is an emerging wastewater carbon capture technology. It utilizes the "famine-feast" cycle of activated sludge microorganisms to capture, flocculate, adsorb, and store carbon sources in wastewater, transferring them to the sludge for separation and removal. Numerous studies have shown that bioflocculation performance is a key factor influencing the rapid capture, adsorption, storage, and separation of different forms of organic matter in wastewater. Therefore, effective bioflocculation management and control are essential for improving carbon capture efficiency.

[0004] The influent to urban wastewater treatment plants in my country typically exhibits highly fluctuating organic matter content and composition. Current contact stabilization processes primarily employ SRT-based operation control methods with constant SRT or constant MLSS, which are unable to adapt to variations in water quality and environmental conditions. This results in significant fluctuations in process biomass and biological activity, poor sludge bioflocculation performance, and inadequate rapid settling and separation of sludge after COD entrainment, leading to low and unstable organic matter capture efficiency in the system. Therefore, there is an urgent need to develop a new control system and method to improve the carbon capture efficiency and operational stability of contact oxidation processes under fluctuating water quality and environmental conditions, thus ensuring the efficient recovery and utilization of carbon resources from wastewater. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a control system and method for improving the carbon capture efficiency of the contact stabilization process. This enhances the rapid flocculation, capture, adsorption, storage and separation performance of activated sludge microorganisms for different forms of organic matter under different water quality and environmental conditions, reduces the ineffective mineralization loss and runoff of organic matter, and improves the carbon capture efficiency and operational stability of the contact stabilization process.

[0006] The present invention discloses a control system for improving carbon capture efficiency in a contact stabilization process, comprising a first electromagnetic flowmeter installed on the inlet pipe of the contact stabilization process unit, a variable frequency sludge discharge pump and a second electromagnetic flowmeter installed sequentially on the sludge discharge pipe of the contact stabilization process unit along the sludge discharge direction, an oxygen consumption and respiration rate detector installed in the contact tank and stabilization tank of the contact stabilization process unit respectively, a sludge concentration detector installed in the contact tank and stabilization tank respectively, and a suspended solids detector installed on the outlet pipe of the contact stabilization process unit. The data acquisition and control module is connected to the first electromagnetic flowmeter, the second electromagnetic flowmeter, the two oxygen consumption and respiration rate detectors, the two sludge concentration detectors, the suspended solids detector, and the variable frequency sludge discharge pump via control lines.

[0007] The present invention provides a control method for improving carbon capture efficiency in a contact stabilization process, comprising the following steps:

[0008] Step 1: Configure OUR in the data acquisition and control modules respectively. Ratio OUR's online setting value Higher and below

[0009] Limit setting value OUR Lower OUR Ratio This represents the ratio of the oxygen consumption and respiration rate in the contact tank to the oxygen consumption and respiration rate in the stabilization tank.

[0010] Among them OUR Higher OUR takes values ​​between 0.9 and 1.2. Lower It takes a value between 0.5 and 0.8;

[0011] Step 2: The data acquisition and control module reads in real time the influent flow rate data output by the first electromagnetic flowmeter, the sludge discharge flow rate data output by the second electromagnetic flowmeter, the OUR data output by the oxygen respiration rate detectors in the contact tank and stabilization tank, the MLSS data output by the sludge concentration detectors in the contact tank and stabilization tank, and the effluent SS data output by the suspended solids detector. The detection cycle of the oxygen respiration rate detectors in the contact tank and stabilization tank is set to Δt1min, and the detection cycles of the first and second electromagnetic flowmeters, the sludge concentration detectors in the contact tank and stabilization tank, and the suspended solids detectors are set to Δt2min. Here, OUR refers to oxygen respiration rate; MLSS refers to sludge concentration; and SS refers to suspended solids.

[0012] Step 3: The data acquisition and control module outputs a control signal to the variable frequency sludge pump, adjusting the pump's operating frequency until the initial sludge discharge capacity reaches Q. waste，0 The specific process is as follows:

[0013] The first step involves the data acquisition and control module calculating the initial sludge discharge volume Q based on the influent flow rate data, MLSS data, and effluent SS data output at time Δt2 from the first electromagnetic flowmeter, the sludge concentration detectors at the contact tank and stabilization tank, and the suspended solids detector. Waste，0 The calculation method is as follows:

[0014]

[0015] In the formula: Q Waste，0 X represents the initial sludge discharge volume of the system. contactor，Δt2 and X stabilizer，Δt2 These are the real-time MLSS monitoring data of the contact pool and the stabilization pool at time Δt2, respectively; Q In，Δt2 This refers to the real-time monitoring data of the influent flow rate at time Δt2; SS Ef，Δt2 This refers to the real-time SS monitoring data of the effluent at time Δt2; V contactor and V stabilizer These represent the effective volumes of the contact tank and stabilization tank in the contact stabilization process unit, respectively; SRT0 is the initial sludge age of the system, ranging from 0.2 to 1.5 days.

[0016] The second step involves the data acquisition and control module sending a control signal to the variable frequency sludge pump to start it and begin sludge discharge. The operating frequency of the variable frequency sludge pump is then adjusted until the initial sludge discharge capacity reaches Q. Waste，0

[0017] Step 4: The data acquisition and control module calculates the OUR (Oxygen Consumption and Respiration Rate) using a formula based on the real-time OUR data output by the oxygen consumption and respiration rate detectors at different times in the contact tank and stabilization tank. Ratio，T The system will then make the following judgments. If any one of the judgment conditions is met, it indicates that the oxygen consumption and respiration rate detector data is abnormal. The data acquisition and control module will stop automatic operation and prompt the operator to perform maintenance on the detector until the maintenance is completed and the oxygen consumption and respiration rate detector data is normal. Then, the data acquisition and control module will repeat steps two to four. Otherwise, it will proceed to step five.

[0018]

[0019] The judgment conditions are as follows:

[0020] Judgment Condition 1: Real-time detection data of the contact pool OUR at time T. contactor，T <2 mg O2 / L·hr or OUR contactor , T >100mg O2 / L·hr;

[0021] Judgment Condition 2: Stabilizing the real-time detection data of the OUR pool at time T. stabilizer，T <5mg O2 / L·hr or OURstabilizer，T >120 mg O2 / L·hr;

[0022] Judgment Condition 3: The ratio of the real-time OUR detection data of the contact pool at time T to the real-time OUR detection data of the stabilization pool at time T. Ratio，T <0.1 or OUR Ratio，T >3.0;

[0023] In the formula: OUR contactor，T For the real-time detection data of the contact pool OUR at the T detection time, OUR stabilizer，T The OUR is the real-time detection data of the stable pool at time T; Ratio，T Δt1 is the ratio of the real-time OUR detection data of the contact pool to the real-time OUR detection data of the stabilization pool at time T; T is the detection time of the oxygen consumption and respiration rate detectors at the contact pool and the stabilization pool, T = Δt1, 2Δt1, 3Δt1, 4Δt1, ..., kΔt1; Δt1 is the detection period of the oxygen consumption and respiration rate detectors at the contact pool and the stabilization pool.

[0024] Step 5: The data acquisition and control module calculates ΔOUR. T The calculation formula is as follows:

[0025] When OUR Ratio，T >OUR Higher hour:

[0026] ΔOUR T =α*(OUR) Ratio，T -OUR Higher )

[0027] When OUR Ratio，T <OUR Lower hour:

[0028] ΔOUR T =α*(OUR) Lower -OUR Ratio，T )

[0029] When OUR Lower ≤OUR Ratio，T ≤OUR Higher hour:

[0030] ΔOUR T =β*(OUR) Ratio，T -OUR Higher )

[0031] In the formula: ΔOUR T ΔOUR is the calculated value at time T; α and β are correction coefficients; where α takes values ​​of 0.5 to 0.6 and β takes values ​​of 1.8 to 2.0.

[0032] Step Six: The data acquisition and control module calculates OUR. set，T+Δt1 The calculation formula is as follows:

[0033]

[0034] In the formula: OUR set，T OUR is the calculated value of OUR at time T. set，T+Δt1 The OUR value is calculated at the detection time T+Δt1; the OUR value is calculated at T=Δt1. set，T The initial value of OUR set，T The initial value is the real-time detection data of the contact pool OUR at time Δt1;

[0035] Step 7: The data acquisition and control module calculates OUR. set，i and OUR contactor，i The calculation formula is as follows:

[0036]

[0037]

[0038] In the formula, OUR set，i and OUR contactor，i OUR represents the time interval from the (i-1)th to the ith hour of system operation. set，j1 and OUR contactor，j1 The average value of OUR; set，j1 The OUR value is calculated at detection time j1. When j1 is equal to T, the OUR is... set，j1 The value of OUR is equal to the calculated value of OUR at time T. set，T OUR contactor，j1 For the real-time detection data of the contact pool OUR at the detection time j1, when j1 is equal to T, OUR contactor，j1 The value of OUR is equal to the real-time detection data of the contact pool at the detection time T. contactor，T j1 = T2-(n1-1)Δt1, T2-(n1-2)Δt1, T2-(n1-3)Δt1......T2-(n1-n1)Δt1; T2 is the last detection time of the oxygen consumption and respiration rate detectors at the contact pool and stabilization pool during the i-1 to i-1 hour period of system operation; i is the number of hours the system has been running, i = 1, 2, 3......k; n1 is an integer;

[0039] Step 8: The data acquisition and control module, based on OUR... set，i and OUR contactor，i Numerical calculation to adjust the sludge discharge flow rate Q of the contact stabilization process unit Waste，i The calculation method is as follows:

[0040] When OURset，i <OUR contactor，i hour:

[0041] Q Waste，i =Q Waste，i-1 +γQ Waste，i-1

[0042] When OUR set，i ≥OUR contactor，i hour:

[0043] Q Waste，i =Q Waste，i-1 -γQ Waste，i-1

[0044] In the formula: Q Waste，i-1 and Q waste，i These are the calculated sludge discharge flow rates of the variable frequency sludge pump in the (i-1)th hour and the ith hour, respectively; i

[0045] The system operates in hours, i = 1, 2, 3...k; γ is the adjustment step size, with a value of 5% to 10%;

[0046] Step 9: The data acquisition and control module, based on Q... waste，i Calculated value, feedback control adjusts the operating frequency of the variable frequency sludge pump, current sludge discharge flow rate is lower than Q Waste，i When calculating values, increase the operating frequency; the current sludge discharge flow rate is higher than Q. Waste，i Calculate the value, reduce the operating frequency, until the sludge discharge flow rate of the variable frequency sludge pump reaches Q. Waste，i Calculated value;

[0047] Step 10: The data acquisition and control module calculates X based on the real-time influent flow rate data output by the first electromagnetic flowmeter at different times, the real-time MLSS data output by the sludge concentration detectors at the contact tank and stabilization tank at different times, and the real-time effluent SS data output by the suspended solids detector at different times. contactor，i X stabilizer，i Q In，i and SS Ef，i The calculation formulas are as follows:

[0048]

[0049]

[0050]

[0051] In the formula: X contactor，i and X stabilizer，i Q represents the average MLSS of the contact pool and the stabilization pool during the period from the (i-1)th to the ith hour of system operation; In，iThe average influent flow rate during the period from the (i-1)th to the ith hour of system operation; SS Ef，i X is the average SS (suspended solids) in the effluent during the period from the (i-1)th to the ith hour of system operation; contactor，j2 For the real-time MLSS detection data of the contact pool at time j2, when j2 equals T1, X contactor，j2 The value is equal to the real-time detection data X of the contact pool MLSS at detection time T1. contactor，T1 ;X stabilizer，j2 For the MLSS real-time detection data of the stable pool at time j2, when j2 equals T1, X stabilizer，j2 The value is equal to the real-time detection data X of the stabilization pool MLSS at detection time T1. stabilizer，T1 Q In，j2 For the real-time influent flow rate at time j2, when j2 equals T1, Q In，j2 The value of is equal to the real-time detection data of the influent flow rate Q at detection time T1. In，T1 ;SS Ef，j2 For the real-time SS detection data of the effluent at time j2, when j2 equals T1, SS Ef，j2 The value of is equal to the real-time detection data of SS in the effluent at detection time T1. Ef，T1 T1 represents the detection time of the first and second electromagnetic flowmeters, the sludge concentration detectors in the contact tank and the stabilization tank, and the suspended solids detectors. T1 = Δt2, 2Δt2, 3Δt2, 4Δt2, ..., kΔt2, in minutes; j2 = T3 - (n2 - 1)Δt2, T3 - (n2 - 2)Δt2, T3 - (n2 - 3)Δt2, ..., T3 - (n2 - n2)Δt2; T3 represents the last detection time of the first and second electromagnetic flowmeters, the sludge concentration detectors in the contact tank and the stabilization tank during the (i-1)th to the ith hour of system operation; n2 is an integer.

[0052] Step 11: The data acquisition and control module, based on X... contactor，i X stabilizer，i Q In，i SS Ef，i and Q Waste，i Calculated values ​​for the actual SRT during the operation of the contact-stabilized process unit. i The correction is performed using the following formula:

[0053]

[0054] Where: SRT i This is the sludge age correction value for the contact stabilization process unit at the i-th hour;

[0055] Step 12: When 0.2d < SRT iWhen the time is <1.5 days, the system repeats steps two through twelve, adjusting the sludge discharge rate of the contact stabilization process unit in real time; when the SRT... i ≤0.2d or SRT i When the value is ≥1.5d, then the current OUR in step one is... Ratio The set value is reset, where SRT i When ≤0.2d, reduce the current OUR. Ratio OUR's online setting value Higher Increase the current OUR Ratio The lower limit setting value OUR Lower When SRT correction is ≥1.5d, increase the current OUR. Ratio OUR's online setting value Higher Reduce the current OUR Ratio The lower limit setting value OUR Lower Reset OUR Ratio After setting the upper and lower limits, the system continues to repeat steps two through twelve, adjusting the sludge discharge rate of the contact stabilization process unit in real time.

[0056] The beneficial effects of this invention are:

[0057] ① Fully utilize the alternating "starvation-fullness" environment characteristic of the contact-stabilized process, based on the contact area

[0058] Real-time detection of the oxygen consumption and respiration rate (OUR) in the stable zone allows for dynamic regulation of the system's biomass and biological activity, promoting the formation of intracellular and extracellular polymers and energy storage substances in microorganisms. This enables the screening of microorganisms with high adsorption, high flocculation, and high storage capabilities, thereby enhancing the rapid capture, flocculation, adsorption, and storage performance of dissolved, particulate, and colloidal organic matter in wastewater.

[0059] ② It enhances the bioflocculation performance of microorganisms in the contact stabilization process, improves the rapid settling and separation performance of sludge after it has been "saturated" with COD, reduces the ineffective mineralization loss and runoff of organic matter during the treatment process, improves the carbon capture efficiency of the contact stabilization process, maximizes the transfer of organic matter to sludge, and maximizes sludge production.

[0060] ③ Significantly improves the adaptability of the contact stabilization process to water quality and environmental conditions, ensuring the stability of process operation. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the control system for improving carbon capture efficiency in a contact stabilization process according to the present invention.

[0062] Figure 2 This is a control flowchart of the control method of the present invention. Detailed Implementation

[0063] To make the technical means, objectives and effects of the present invention easier to understand, the technical solutions of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0064] As attached Figure 1 The present invention illustrates a control system for improving the carbon capture efficiency of a contact stabilization process. This control system is installed on an existing contact stabilization process unit, which is a wastewater treatment carbon capture process. The specific structure of this process can be found in "Research on an Emerging Wastewater Treatment Carbon Capture Technology HICS" in the 2020 supplement of the journal "Water Supply and Drainage", Vol. 46, pp. 43-46.

[0065] The control system includes a first electromagnetic flowmeter 6-1 installed on the inlet pipe 1 of the contact stabilization process unit, a variable frequency sludge discharge pump 5 and a second electromagnetic flowmeter 6-2 installed sequentially on the sludge discharge pipe 3 of the contact stabilization process unit along the sludge discharge direction, an oxygen consumption respiration rate detector (OUR detector) 7 installed in the contact tank and stabilization tank of the contact stabilization process unit, a sludge concentration detector (MLSS detector) 8 installed in the contact tank and stabilization tank, and a suspended solids detector (SS detector) 9 installed on the outlet pipe 2 of the contact stabilization process unit. The data acquisition and control module 4 is connected to the first electromagnetic flowmeter, the second electromagnetic flowmeter, the two oxygen consumption respiration rate detectors, the two sludge concentration detectors, the suspended solids detector, and the variable frequency sludge discharge pump via control lines.

[0066] The outlet of the inlet pipe is aligned with the contact tank, the inlet of the sludge discharge pipe is connected to the sludge discharge port on the bottom wall of the contact tank, and the inlet of the outlet pipe is connected to the outlet on the upper side wall of the sedimentation tank. The sedimentation outlet on the bottom wall of the sedimentation tank is connected to the inlet at the bottom of the stabilization tank via a pipeline, and the upper part of the contact tank and the upper part of the sedimentation tank are connected by a connecting pipeline.

[0067] In the figure: OUR: oxygen consumption respiration rate; MLSS: sludge concentration; SS: suspended solids.

[0068] Reference Figure 2 A control method for improving carbon capture efficiency in a contact stabilization process includes the following steps:

[0069] Step 1: Configure OUR in the data acquisition and control modules respectively. Ratio OUR's online setting value Higher and the lower limit setting value OUR Lower OUR Ratio This represents the ratio of the oxygen consumption and respiration rate in the contact tank to the oxygen consumption and respiration rate in the stabilization tank.

[0070] Among them OUR Higher OUR takes values ​​between 0.9 and 1.2. Lower It takes a value between 0.5 and 0.8.

[0071] Step 2: The data acquisition and control module reads in real time the influent flow rate data output by the first electromagnetic flow meter, the sludge discharge flow rate data output by the second electromagnetic flow meter, the OUR data output by the oxygen consumption and respiration rate detectors in the contact tank and stabilization tank, the MLSS data output by the sludge concentration detectors in the contact tank and stabilization tank, and the effluent SS data output by the suspended solids detector. The detection cycle of the oxygen consumption and respiration rate detectors in the contact tank and stabilization tank is set to Δt1min, and the detection cycles of the first electromagnetic flow meter, the second electromagnetic flow meter, the sludge concentration detectors in the contact tank and stabilization tank, and the suspended solids detectors are set to Δt2min.

[0072] Step 3: The data acquisition and control module outputs a control signal to the variable frequency sludge pump, adjusting the pump's operating frequency until the initial sludge discharge capacity reaches Q. Waste，0 The specific process is as follows:

[0073] The first step involves the data acquisition and control module calculating the initial sludge discharge volume Q based on the influent flow rate data, MLSS data, and effluent SS data output at time Δt2 from the first electromagnetic flowmeter, the sludge concentration detectors at the contact tank and stabilization tank, and the suspended solids detector. waste，0 The calculation method is as follows:

[0074]

[0075] In the formula: Q waste，0 This represents the initial sludge discharge volume of the system, in cubic meters (m³). 3 / hr;X contactor，Δt2 and X stabilizer，Δt2 The data are the real-time MLSS monitoring data of the contact tank and stabilization tank at time Δt2 (i.e., the real-time monitoring data of the sludge concentration at the contact tank and stabilization tank at the time of the first monitoring cycle), in mg / L; Q In，Δt2 The data represents the real-time influent flow rate at time Δt2 (i.e., the real-time flow rate of the first electromagnetic flowmeter during the first detection cycle), in meters per second (m). 3 / h;SS Ef，Δt2 The data represents the real-time SS (suspended solids) detection data of the effluent at time Δt2 (i.e., the real-time detection data of the suspended solids analyzer at the first detection cycle), in mg / L; V contactor and V stabilizer These are the effective volumes of the contact pool and stabilization pool in the contact stabilization process unit, respectively, in cubic meters (m³). 3 SRT0 is the initial sludge age of the system, in days, and ranges from 0.2 to 1.5 days.

[0076] The second step involves the data acquisition and control module sending a control signal to the variable frequency sludge pump to start it and begin sludge discharge. The operating frequency of the variable frequency sludge pump is then adjusted until the initial sludge discharge capacity reaches Q. Waste，0 .

[0077] Step 4: The data acquisition and control module calculates the OUR (Oxygen Consumption and Respiration Rate) using a formula based on the real-time OUR data output by the oxygen consumption and respiration rate detectors at different times in the contact tank and stabilization tank. Ratio，T The system will then make the following judgments. If any one of the judgment conditions is met, it indicates that the oxygen consumption and respiration rate detector data is abnormal. The data acquisition and control module will stop automatic operation and prompt the operator to perform maintenance on the detector until the maintenance is completed and the oxygen consumption and respiration rate detector data is normal. Then, the data acquisition and control module will repeat steps two to four. Otherwise, it will proceed to step five.

[0078]

[0079] The judgment conditions are as follows:

[0080] Judgment Condition 1: Real-time detection data of the contact pool OUR at time T. contactor，T <2 mg O2 / L·hr or OUR contactor，T >100mg O2 / L·hr;

[0081] Judgment Condition 2: Stabilizing the real-time detection data of the OUR pool at time T. stabilizer，T <5mg O2 / L·hr or OUR stabilizer，T >120 mg O2 / L·hr;

[0082] Judgment Condition 3: The ratio of the real-time OUR detection data of the contact pool at time T to the real-time OUR detection data of the stabilization pool at time T. Ratio，T <0.1 or OUR Ratio，T >3.0;

[0083] In the formula: OUR contactor，T For the real-time detection data of the contact pool OUR at the T detection time, OUR stabilizer，T The OUR data is the real-time detection data of the stable cell at time T, in mg O2 / L·hr. Ratio，T Δt1 is the ratio of the real-time OUR data of the contact pool to the real-time OUR data of the stabilization pool at time T; T is the detection time of the oxygen consumption and respiration rate detectors at the contact pool and the stabilization pool, T = Δt1, 2Δt1, 3Δt1, 4Δt1...kΔt1, in min; Δt1 is the detection cycle of the oxygen consumption and respiration rate detectors at the contact pool and the stabilization pool, in min.

[0084] Step 5: The data acquisition and control module calculates ΔOUR. T The calculation formula is as follows:

[0085] When OUR Ratio，T >OUR Higher hour:

[0086] ΔOUR T =α*(OUR) Ratio，T -OUR Higher )

[0087] When OUR Ratio，T <OUR Lower hour:

[0088] ΔOUR T =α*(OUR) Lower -OUR Ratio，T )

[0089] When OUR Lower ≤OUR Ratio，T ≤OUR Higher hour:

[0090] ΔOUR T =β*(OUR) Ratio，T -OUR Higher )

[0091] In the formula: ΔOUR T ΔOUR is the calculated value at time T, in mg O2 / L·hr; T is the detection time of the oxygen consumption and respiration rate detectors at the contact tank and stabilization tank, in min; T = Δt1, 2Δt1, 3Δt1, 4Δt1...kΔt1; Δt1 is the detection cycle of the oxygen consumption and respiration rate detectors at the contact tank and stabilization tank, in min. α and β are correction coefficients. α ranges from 0.5 to 0.6, and β ranges from 1.8 to 2.0.

[0092] Step Six: The data acquisition and control module calculates OUR. set，T+Δt1 The calculation formula is as follows:

[0093]

[0094] In the formula: OUR set，T OUR is the calculated value of OUR at time T. set，T+Δt1OUR is the calculated value at the detection time T+Δt1, in mg O2 / L·hr; T is the detection time of the oxygen consumption and respiration rate detectors at the contact tank and stabilization tank, T = Δt1, 2Δt1, 3Δt1, 4Δt1...kΔt1, in min; Δt1 is the detection cycle of the oxygen consumption and respiration rate detectors at the contact tank and stabilization tank, in min; OUR is calculated at T = Δt1. set，T The initial value of OUR set，T The initial value is the real-time detection data of OUR in the contact pool at time Δt1 (i.e., the real-time detection data of the oxygen consumption and respiration rate detector at the contact pool at the time of the first detection cycle).

[0095] Step 7: The data acquisition and control module calculates OUR. set，i and OUR contactor，i The calculation formula is as follows:

[0096]

[0097]

[0098] In the formula, OUR set，i and OUR contactor，i OUR represents the time interval from the (i-1)th to the ith hour of system operation. set，j1 and OUR contactor，j1 The average value is expressed in mg O2 / L·hr; OUR set，j1 The OUR value is calculated at detection time j1. When j1 is equal to T, the OUR is... set，j1 The value of OUR is equal to the calculated value of OUR at time T. set，T The unit is mg O2 / L·hr; OUR contactor，j1 For the real-time detection data of the contact pool OUR at the detection time j1, when j1 is equal to T, OUR contactor，j1 The value of OUR is equal to the real-time detection data of the contact pool at the detection time T. contactor，T The units are mg O2 / L·hr; T is the detection time of the oxygen consumption and respiration rate detectors at the contact pool and stabilization pool, T = Δt1, 2Δt1, 3Δt1, 4Δt1...kΔt1, in min; j1 = T2-(n1-1)Δt1, T2-(n1-2)Δt1, T2-(n1-3)Δt1...T2-(n1-n1)Δt1, in min; T2 is the last detection time of the oxygen consumption and respiration rate detectors at the contact pool and stabilization pool during the i-1 to i-th hour of system operation, in min; Δt1 is the detection cycle of the oxygen consumption and respiration rate detectors at the contact pool and stabilization pool, in min; i is the number of system operating hours, i = 1, 2, 3...k, in hr; n1 is an integer.

[0099] Step 8: The data acquisition and control module, based on OUR... set，i and OUR contactor，i Numerical calculation to adjust the sludge discharge flow rate Q of the contact stabilization process unit Waste，i The calculation method is as follows:

[0100] When OUR set，i <OUR contactor，i hour:

[0101] Q Waste，i =Q Waste，i-1 +γQ Waste，i-1

[0102] When OUR set，i ≥OUR contactor，i hour:

[0103] Q Waste，i =Q Waste，i-1 -γQ Waste，i-1

[0104] In the formula: Q Waste，i-1 and Q Waste，i These are the calculated sludge discharge flow rates of the variable frequency sludge pump in the (i-1)th hour and the ith hour, respectively, in m³. 3 / hr; i is the system operating hours, i = 1, 2, 3...k, in hr; γ is the adjustment step size, γ takes a value of 5% to 10%; the initial sludge discharge capacity of the variable frequency sludge pump is Q. Waste，0 .

[0105] Step 9: The data acquisition and control module, based on Q... Waste，i Calculated value, feedback control adjusts the operating frequency of the variable frequency sludge pump, current sludge discharge flow rate is lower than Q waste，i Increase the operating frequency during calculation. The current sludge discharge flow rate is higher than Q. Waste，i Calculate the value, reduce the operating frequency, until the sludge discharge flow rate of the variable frequency sludge pump reaches Q. Waste，i Calculated value;

[0106] Step 10: The data acquisition and control module calculates X based on the real-time influent flow rate data output by the first electromagnetic flowmeter at different times, the real-time MLSS data output by the sludge concentration detectors at the contact tank and stabilization tank at different times, and the real-time effluent SS data output by the suspended solids detector at different times. contactor，i X stabilizer，i Q In，i and SS Ef，i The calculation formulas are as follows:

[0107]

[0108]

[0109]

[0110] In the formula: X contactor，i and X stabilizer，i Q represents the average MLSS of the contact tank and the stabilization tank during the period from the (i-1)th to the ith hour of system operation, in mg / L; In，i This represents the average influent flow rate during the period from the (i-1)th to the ith hour of system operation, in meters per second (m³). 3 / hr;SS Ef，i X represents the average suspended solids (SS) in the effluent during the period from the (i-1)th to the ith hour of system operation, expressed in mg / L; contactor，j2 For the real-time MLSS detection data of the contact pool at time j2, when j2 equals T1, X contactor，j2 The value is equal to the real-time detection data X of the contact pool MLSS at detection time T1. contactor，T1 The unit is mg / L; X stabilizer，j2 For the MLSS real-time detection data of the stable pool at time j2, when j2 equals T1, X stabilizer，j2 The value is equal to the real-time detection data X of the stabilization pool MLSS at detection time T1. stabilizer，T1 The unit is mg / L; Q In，j2 For the real-time influent flow rate at time j2, when j2 equals T1, Q In，j2 The value of is equal to the real-time detection data of the influent flow rate Q at detection time T1. In，T1 The unit is m 3 / h;SS Ef，j2 For the real-time SS detection data of the effluent at time j2, when j2 equals T1, SS Ef，j2 The value of is equal to the real-time detection data of SS in the effluent at detection time T1. Ef，T1 The units are mg / L; T1 is the detection time of the sludge concentration detector and suspended solids detector at the first and second electromagnetic flowmeters, the contact tank, and the stabilization tank, T1 = Δt2, 2Δt2, 3Δt2, 4Δt2...kΔt2, in min; j2 = T3-(n2-1)Δt2, T3-(n2-2)Δt2, T3-(n2-3)Δt2...T3-(n2-n2)Δt2, in min; T3 is the last detection time of the sludge concentration detector and suspended solids detector at the first and second electromagnetic flowmeters, the contact tank, and the stabilization tank during the period from the (i-1)th to the ith hour of system operation, in min; Δt2 is the detection cycle of the sludge concentration detector and suspended solids detector at the first and second electromagnetic flowmeters, the contact tank, and the stabilization tank, in mg / L;

[0111] `min`; `i` is the system running hours, `i = 1, 2, 3...k`, in hr; `n²` is an integer. Step 11: The data acquisition and control module, based on `X`... contactor，i X stabilizer，i Q In，i SS Ef，i and Q Waste，i Calculated values ​​for the actual SRT during the operation of the contact-stabilized process unit. i The correction is performed using the following formula:

[0112]

[0113] Where: SRT i V represents the sludge age correction value for the contact stabilization process unit at hour i, in days (d). contactor and V stabilizer These are the effective volumes of the contact pool and stabilization pool in the contact stabilization process unit, respectively, in cubic meters (m³). 3 i represents the system's operating hours, where i = 1, 2, 3...k, and the unit is hours (h).

[0114] Step 12: When 0.2d < SRT i When the time is <1.5 days, the system repeats steps two through twelve, adjusting the sludge discharge rate of the contact stabilization process unit in real time; when the SRT... i ≤0.2d or SRT i When the value is ≥1.5d, then the current OUR in step one is... Ratio The set value is reset, where SRT i When <0.2d, reduce the current OUR. Ratio OUR's online setting value Higher Increase the current OUR Ratio The lower limit setting value OUR Lower When SRT correction is ≥1.5d, increase the current OUR. Ratio OUR's online setting value Higher Reduce the current OUR Ratio The lower limit setting value OUR Lower Reset OUR Ratio After setting the upper and lower limits, the system continues to repeat steps two through twelve, adjusting the sludge discharge rate of the contact stabilization process unit in real time.

[0115] To further understand the implementation effects of the present invention, the following description is based on experimental examples. The scope of protection of the present invention is not limited by the following experimental examples.

[0116] Experimental example:

[0117] The effluent from the aerated grit chamber of a municipal wastewater treatment plant was treated using a contact stabilization process. The total effective volume of the contact stabilization process unit was 220L, and the water temperature during operation was 12-24℃. The operating effect of the contact stabilization process unit and the efficiency of organic matter transfer and capture in the raw water were investigated under the control system and method of this invention and under the constant SRT control method. The results are shown in Table 1.

[0118] (1) The control system and method of the present invention

[0119] Using the control system and method of this invention, OUR Higher and OUR Lower The values ​​were set to 0.95 and 0.6 respectively, with correction factors α and β set to 0.5 and 2.0. The OUR detection cycle Δt1 was set to 20 minutes, and the detection cycles Δt2 for the electromagnetic flowmeter, MLSS, and SS were set to 5 minutes. During operation, OUR... contactor and OUR stabilizer The measured values ​​were 24.15–44.31 mg O2 / Lh and 28.66–49.80 mg O2 / Lh, respectively. Ratio The concentrations ranged from 0.56 to 1.15 mg / L, and the MLSS ranged from 402.09 to 815.41 mg / L. The SRT ranged from 0.56 to 1.22 during this operating period.

[0120] (2) Using constant SRT control method

[0121] A constant SRT-based control method was adopted, which controls the sludge discharge rate of the contact stabilization process unit by fixing the operating SRT value. The SRT was controlled between 0.3 and 1.2 days, and the MLSS was between 53 and 1470 mg / L during operation.

[0122] Compared with the constant SRT control method, after operating the control system and method of the present invention, the sludge biological activity VSS / SS of the contact stabilization process unit increased from 0.54-0.67 to 0.63-0.78, an average increase of 40%, and the content of extracellular polymeric substances (EPS) of microorganisms in the contact zone increased from 230-471 mg COD / VSS to 416-650 mg COD / VSS, an average increase of 43%.

[0123] The above comparisons demonstrate that, by adopting the control system and method of this invention, the bioflocculation activity of the biomass microorganisms in the contact stabilization process unit is enhanced, the extracellular polymer content of the microorganisms is increased, and the capture, adsorption, storage, and separation performance of dissolved, particulate, and colloidal organic matter in wastewater is improved. Ultimately, the ineffective mineralization removal rate of organic matter is reduced from 12%–40% to 7%–25%, an average reduction of 46%, and the capture and transfer rate of organic matter is increased from 25%–65% to 43%–74%, an average increase of 39%. This significantly improves the process's capture efficiency of organic matter in raw water, thereby facilitating the subsequent energy utilization of sludge and enhancing the level of energy utilization.

[0124] Table 1. Operational effect of the contact stabilization process unit

[0125]

[0126]

[0127] Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope thereof, and all such changes and modifications should be considered within the scope of protection of the present invention.

Claims

1. A control method for improving the carbon capture efficiency of a contact stabilization process, characterized in that: the control system comprises a first electromagnetic flowmeter (6-1) installed on the influent pipe (1) of the contact stabilization process unit, a variable frequency sludge discharge pump (5), a second electromagnetic flowmeter (6-2), oxygen uptake rate detectors (7) installed in the contact tank and the stabilization tank respectively, sludge concentration detectors (8) installed in the contact tank and the stabilization tank respectively, a suspended solids detector (9) installed on the effluent pipe (2) of the contact stabilization process unit, and a data acquisition and control module (4) connected to the first electromagnetic flowmeter, the second electromagnetic flowmeter, the two oxygen uptake rate detectors, the two sludge concentration detectors, the suspended solids detector, and the variable frequency sludge discharge pump through control lines respectively; the control system performs the following steps: step two, the data acquisition and control module reads the influent flow data output by the first electromagnetic flowmeter, the sludge discharge flow data output by the second electromagnetic flowmeter, the OUR data output by the oxygen uptake rate detectors in the contact tank and the stabilization tank respectively, the MLSS data output by the sludge concentration detectors in the contact tank and the stabilization tank respectively, and the effluent SS data output by the suspended solids detector in real time, wherein the detection period of the oxygen uptake rate detectors in the contact tank and the stabilization tank is set to Δt1 min, and the detection period of the first electromagnetic flowmeter, the second electromagnetic flowmeter, the sludge concentration detectors in the contact tank and the stabilization tank, and the suspended solids detector is set to Δt2 min, wherein OUR refers to oxygen uptake rate, MLSS refers to sludge concentration, and SS refers to suspended solids; the judgment condition is as follows: ​ ​ Step one, set the upper limit set value OUR Ratio and the lower limit set value OUR Higher in the data acquisition and control module, OUR Lower represents the ratio of the oxygen consumption rate of the contact tank and the oxygen consumption rate of the stabilization tank Ratio ; where OUR Higher between 0.9 and 1.2, OUR Lower between 0.5 and 0.8; ​ Step three, the data acquisition and control module outputs a control signal to the variable frequency sludge pump, adjusts the operating frequency of the variable frequency sludge pump until the initial sludge discharge of the variable frequency sludge pump reaches Q Waste,0 The specific process is as follows: Firstly, the data acquisition and control module calculates the initial sludge discharge Q according to the influent flow data, MLSS data and effluent SS data output by the first electromagnetic flowmeter, the contact cell and the stable cell at time Δt2. Waste,0 The calculation method is as follows: In the formula: Q Waste,0 Q0 is the initial sludge discharge of the system; X contactor,Δt2 and X stabilizer,Δt2 are respectively the real-time detection data of MLSS of the contact tank and the stabilization tank at Δt2; Q In,Δt2 is the real-time detection data of the influent flow at Δt2; SS Ef,Δt2 is the real-time detection data of the effluent SS at Δt2; V contactor and V stabilizer are respectively the effective tank capacity of the contact tank and the stabilization tank of the contact and stabilization process unit; SRT0 is the initial sludge age of the system, and the value is 0.2-1.5 d; Second step, the data acquisition and control module outputs control signal to the variable frequency sludge pump to start the variable frequency sludge pump to start sludge discharge, adjusts the running frequency of the variable frequency sludge pump until the initial sludge discharge of the variable frequency sludge pump reaches Q Waste,0 ; Step four, the data acquisition and control module calculates the OUR according to the real-time detection data of the OUR detection instrument at different time outputs from the contact tank and the stabilization tank, through the formula Ratio,T And the following judgment is made: if one of the judgment conditions is met, it indicates that the detection data of the oxygen consumption respiration rate detection instrument is abnormal, the data acquisition and control module stops automatic operation, and prompts the operator to maintain the detection instrument until the maintenance is completed and the detection data of the oxygen consumption respiration rate detection instrument is normal, and then the data acquisition and control module repeats steps two to four, otherwise step five is executed: ​ Condition 1, T detection time contact pool OUR real-time detection data OUR contactor,T <2 mg O2 / L·hr or OUR contactor , T >100 mg O2 / L·hr; Condition two, T detection time stable pool OUR real-time detection data OUR stabilizer,T <5 mg O2 / L·hr or OUR stabilizer,T >120 mg O2 / L·hr; Judgment Condition 3: The ratio of the real-time OUR detection data of the contact pool at time T to the real-time OUR detection data of the stabilization pool at time T. Ratio,T <0.1 or OUR Ratio,T >3.0; In the formula: OUR contactor,T For the real-time detection data of the contact pool OUR at the T detection time, OUR stabilizer,T The OUR is the real-time detection data of the stable pool at time T; Ratio,T Δt1 is the ratio of the real-time OUR detection data of the contact pool to the real-time OUR detection data of the stabilization pool at time T; T is the detection time of the oxygen consumption and respiration rate detectors at the contact pool and the stabilization pool, T = Δt1, 2Δt1, 3Δt1, 4Δt1...kΔt1; Δt1 is the detection period of the oxygen consumption and respiration rate detectors at the contact pool and the stabilization pool. Step five, the data acquisition and control module calculates ΔOUR T The calculation formula is as follows: When OUR Ratio,T >OUR Higher : ΔOUR T = a * (OUR Ratio，T - OUR Higher ) When OUR Ratio,T <OUR Lower : ΔOUR T = a * (OUR Lower - OUR Ratio，T ) When OUR Lower ≤ OUR Ratio,T ≤ OUR Higher : ΔOUR T = β * (OUR Ratio,T - OUR Higher ) where: ΔOUR T is the value of ΔOUR at the time of T detection; and α and β are correction factors, where α has a value of 0.5 to 0.6 and β has a value of 1.8 to 2.

0. Step six, the data acquisition and control module calculates the OUR set,T+Δt1 The calculation formula is as follows: OUR = OUR + Δt1 set,T OUR = OUR + Δt1 set,T+Δt1 OUR = OUR + Δt1 set,T OUR = OUR + Δt1 set,T OUR = OUR + Δt1 Step seven, the data acquisition and control module calculates the OUR set,i and the OUR contactor,i , according to the following formula: In the formula, OUR set,i and OUR contactor,i OUR represents the time interval from the (i-1)th to the ith hour of system operation. set,j1 and OUR contactor,j1 The average value of OUR; set,j1 The OUR value is calculated for detection time j1. When j1 equals T, the OUR is... set,j1 The value of OUR is equal to the calculated value of OUR at time T. set,T OUR contactor,j1 For the real-time detection data of the contact pool OUR at the detection time j1, when j1 is equal to T, OUR contactor,j1 The value of OUR is equal to the real-time detection data of the contact pool at the detection time T. contactor,T j1 = T2-(n1-1)Δt1, T2-(n1-2)Δt1, T2-(n1-3)Δt1……T2-(n1-n1)Δt1; T2 is the last detection time of the oxygen consumption and respiration rate detectors at the contact pool and stabilization pool during the i-1 to i-1 hour period of system operation; i is the number of hours the system has been running, i = 1, 2, 3……k; n1 is an integer; Step eight, the data acquisition and control module adjusts the OUR set,i and OUR contactor,i numerically calculates the sludge discharge flow rate Q of the contact stabilization process unit Waste,i , and the calculation method is as follows: When OUR set,i <OUR contactor,i : Q Waste,i = Q Waste,i-1 + γQ Waste，i-1 When OUR set,i ≥ OUR contactor,i : Q Waste,i = Q Waste,i-1 - γQ Waste，i-1 wherein: Q Waste,i-1 and Q Waste,i are the calculated values of the sludge discharge flow rate of the variable frequency sludge discharge pump at the i-1th hour and the ith hour, respectively; i is the number of hours of system operation, i = 1, 2, 3, …, k; and γ is the adjustment step, with γ being 5% to 10%. Step nine, the data acquisition and control module according to Q Waste,i The calculated value, the feedback control adjusts the frequency of the variable frequency sludge pump, and the current sludge flow is lower than Q Waste,i The calculated value, the frequency is increased; the current sludge flow is higher than Q Waste,i The calculated value, the frequency is reduced until the sludge flow of the variable frequency sludge pump reaches Q Waste,i The calculated value; Step ten, the data acquisition and control module respectively detects the real-time data of the influent flow output by the first electromagnetic flowmeter at different times, the real-time data of the MLSS output by the sludge concentration detector at the contact tank and the stabilization tank at different times, and the real-time data of the effluent SS output by the suspended solids detector at different times, and respectively calculates X contactor,i 、X stabilizer,i 、Q In,i and SS Ef,i , and the calculation formulas are as follows: wherein: X contactor,i and X stabilizer,i are the average values of MLSS in the contact tank and the stabilization tank, respectively, during the i-1th to ith hour of system operation; Q In,i is the average value of influent flow rate during the i-1th to ith hour of system operation. SS Ef,i is the average value of effluent SS in the i-1th to ith hour period of system operation; X contactor,j2 is the real-time detection data of MLSS of the contact tank at the j2 detection time, and when j2 is equal to T1, X contactor,j2 is equal to the real-time detection data of MLSS of the contact tank at the T1 detection time X contactor,T1 ; X stabilizer,j2 is the real-time detection data of MLSS of the stable tank at the j2 detection time, and when j2 is equal to T1, X stabilizer,j2 is equal to the real-time detection data of MLSS of the stable tank at the T1 detection time X stabilizer,T1 ; Q In,j2 is the real-time detection data of influent flow at the j2 detection time, and when j2 is equal to T1, Q In,j2 is equal to the real-time detection data of influent flow at the T1 detection time Q In,T1 ; SS Ef,j2 is the real-time detection data of effluent SS at the j2 detection time, and when j2 is equal to T1, SS Ef,j2 is equal to the real-time detection data of effluent SS at the T1 detection time SS Ef,T1 ; T1 is the detection time of the first and second electromagnetic flowmeters, sludge concentration detectors at the contact tank and the stable tank, and suspended matter detectors, T1 = Δt2, 2Δt2, 3Δt2, 4Δt2, …, kΔt2, unit: min; j2 = T3-(n2-1)Δt2, T3-(n2-2)Δt2, T3-(n2-3)Δt2, …, T3-(n2-n2)Δt2; T3 is the last detection time of the first and second electromagnetic flowmeters, sludge concentration detectors at the contact tank and the stable tank, and suspended matter detectors in the i-1th to ith hour period of system operation; n2 is an integer; Step eleven, the data acquisition and control module calculates the value of X contactor,i , Q stabilizer,i , and S In,i , and SS Ef,i and Q Waste,i , and corrects the actual SRT i in the operation of the contact stabilization process unit, and the correction formula is as follows: where: SRT i is the corrected value of the contact stabilization process unit sludge age for the ith hour. Step twelve, when 0.2d < SRT i <1.5d, the system repeats step two to step twelve operation, real-time adjustment of contact stable process unit sludge discharge capacity; when SRT i ≤0.2d or SRT i ≥1.5d, then the current OUR Ratio in step one is revalued, wherein when SRT i ≤0.2d, the upper limit set value OUR Ratio of the current OUR Higher is reduced, and the lower limit set value OUR Ratio of the current OUR Lower is increased; when SRT correction ≥1.5d, the upper limit set value OUR Ratio of the current OUR Higher is increased, and the lower limit set value OUR Ratio of the current OUR Lower is reduced; after the upper and lower limit set values of OUR Ratio are re-set, the system continues to repeat step two to step twelve operation, real-time adjustment of contact stable process unit sludge discharge capacity.

Images