SBR process aeration control method, device and system based on real-time COD monitoring

Abstract

The present invention relates to an SBR process aeration control method, device and system based on real-time COD monitoring, which belongs to the field of sewage treatment and solves the technical problem of high energy consumption of SBR process in the prior art. The method comprises: collecting the current COD concentration and the current aeration time; determining the current COD concentration change rate according to the current COD concentration and the current aeration time; determining the aeration volume reduction rate when determining that the current COD concentration change rate is not greater than the first COD concentration change rate and greater than the second COD concentration change rate; reducing the aeration volume according to the aeration volume reduction rate until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration. The technical solution provided by the present invention reduces the SBR energy consumption by reducing the total aeration volume.

Description

Technical Field

[0001] The present invention belongs to the field of sewage treatment, and in particular relates to a SBR process aeration control method, device and system based on real-time COD monitoring. Background Art

[0002] Aeration is usually used to reduce the chemical oxygen demand (COD) content in sewage during sewage treatment. The COD is usually detected by the potassium dichromate method. During the detection process, the mixed liquid needs to be digested, which will consume a lot of time and result in the inability to obtain real-time COD data during the sewage treatment process. Therefore, it is difficult to perform closed-loop control of the aeration system.

[0003] In order to achieve energy saving and consumption reduction in aeration systems, sewage treatment plants usually use dissolved oxygen (DO) as an indicator to control aeration volume. However, since the target value of dissolved oxygen is usually set based on the experience of operators and the aeration volume is difficult to quantitatively adjust, the DO value fluctuates greatly, making the energy saving effect of the aeration system weak and unable to provide real-time feedback on the actual oxygen demand in the system. Summary of the invention

[0004] In view of the above analysis, the present invention aims to propose an SBR process aeration control method, device and system based on real-time COD monitoring, which can save the energy consumption of SBR by controlling the aeration amount during the aeration stage.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] In one aspect, the present invention provides an SBR process aeration control method for real-time monitoring of COD, comprising:

[0007] Collect current COD concentration and current aeration time;

[0008] Determining a current COD concentration change rate according to the current COD concentration and the current aeration time;

[0009] When it is determined that the current COD concentration change rate is not greater than the first COD concentration change rate and greater than the second COD concentration change rate, determining the aeration volume reduction rate;

[0010] The aeration amount is reduced according to the aeration amount reduction rate until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration.

[0011] Further, determining the aeration volume reduction rate includes:

[0012] According to a preset aeration volume decrease rate range, an aeration volume function is determined, wherein the aeration volume function is a linear function with aeration time as an independent variable and aeration volume as a dependent variable;

[0013] The aeration amount reduction rate is determined according to the aeration amount function.

[0014] Furthermore, the aeration volume function is a random function within a preset aeration volume decrease rate range; the aeration volume decrease rate range is that the aeration volume decreases by 10 units every 20 minutes to 30 minutes.

[0015] Further, a plurality of aeration volume control points are determined, each of which corresponds to an aeration volume to be controlled;

[0016] According to the preset aeration volume decrease rate range and each of the aeration volumes to be controlled, a plurality of aeration volume functions are determined, each of the aeration volume functions is a linear function, with aeration time as an independent variable and aeration volume as a dependent variable;

[0017] According to each of the aeration volume functions, the aeration volume reduction rate corresponding to each of the aeration volume control points is determined.

[0018] Further, when the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration, the current aeration amount is adjusted to a preset aeration amount.

[0019] Furthermore, after each aeration process is completed, the time required for the initial aeration volume to become the preset aeration volume is recorded;

[0020] The average of the recorded times is determined to obtain the target time.

[0021] Further, determining a first coordinate according to the current time and the current aeration amount;

[0022] Determining a second coordinate according to the preset aeration volume and the target time;

[0023] Generate an aeration volume function according to the first coordinate, the second coordinate and a preset aeration volume decrease rate range, wherein the aeration volume function is a nonlinear function with aeration time as an independent variable and aeration volume as a dependent variable;

[0024] Determining the aeration amount reduction rate according to the aeration amount function;

[0025] The aeration volume reduction rate ranges from 10 units of aeration volume every 20 minutes to 30 minutes.

[0026] Further, storing the aeration amount function and the power consumption corresponding to the aeration amount function;

[0027] Determining the generation probability of each of the aeration volume functions according to the power consumption;

[0028] Determining the aeration volume reduction rate includes:

[0029] An aeration volume function is generated according to the generation probability, the first coordinate, the second coordinate, and a preset aeration volume decrease rate range.

[0030] Further, receiving external input power consumption control parameters;

[0031] According to the power consumption control parameter, a target power consumption and an optimized aeration volume function corresponding to the target power consumption are determined, wherein the optimized aeration volume function is used to determine an aeration volume reduction rate; and the power consumption during the aeration process is controlled not to exceed the target power consumption.

[0032] In a second aspect, an embodiment of the present invention provides an SBR process aeration control device based on real-time COD monitoring, comprising: a COD detection probe, a COD analyzer, an editable logic controller, a frequency converter and a blower;

[0033] The COD detection probe is arranged in the SBR reactor, and is used to collect the COD concentration signal in the sewage, and send the COD concentration signal to the COD analyzer;

[0034] The COD analyzer determines the aeration volume reduction rate according to the COD concentration signal when the current COD concentration change rate is not greater than the first COD concentration change rate and greater than the second COD concentration change rate, until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration, obtains the current aeration volume, and sends the current aeration volume to the editable logic controller;

[0035] The editable logic controller determines the operating parameters of the blower according to the current aeration volume, and controls the blower to operate according to the operating parameters through the frequency converter.

[0036] In a third aspect, an embodiment of the present invention provides an SBR process aeration control system based on real-time COD monitoring, which is used to execute the method described in any one of the first aspects, including: an electric energy meter, a second data processing module, the first data processing module, and the device described in the second aspect;

[0037] The electric energy meter is used to record the power consumption during the aeration stage of the SBR tank;

[0038] The first data processing module is used to set the generation probability of the aeration amount function generated by the COD analyzer according to the power consumption recorded by the electric energy meter.

[0039] The second data processing module is used to generate a function of COD concentration changing over time and a function of COD concentration changing rate changing over time based on the historical data of SBR sewage treatment; and determine the first COD concentration changing rate and the second COD concentration changing rate based on the function of COD concentration changing rate changing over time.

[0040] Compared with the prior art, the present invention can achieve at least one of the following technical effects:

[0041] 1. With respect to the decomposition process of COD, the present invention determines the current COD concentration change rate by detecting the COD concentration, and determines the timing of reducing the aeration amount in the SBR aeration stage by using the target COD concentration, the first COD concentration change rate and the second COD concentration change rate. The first COD concentration change rate is used as the starting point of the aeration amount reduction operation, and the target COD concentration and the second COD concentration change rate are used as the end point of the aeration amount reduction operation, and then the aeration amount is maintained unchanged, so as to reduce the aeration amount or maintain the aeration amount at the appropriate time, thereby reducing the total aeration amount and thus reducing the energy consumption of the SBR.

[0042] 2. In actual application scenarios, sewage treatment effect and power consumption are two options that are difficult to balance. The present invention uses random functions to control the aeration volume reduction process, and through statistical correspondence between random functions and power consumption, it is possible to flexibly adjust the aeration volume when treating sewage according to indicators such as sewage treatment volume, component content in sewage, and electricity consumption period, thereby taking into account the requirements of improving sewage treatment effect and reducing energy consumption.

[0043] 3. The technical solution provided by the present invention can reduce power consumption by 10-30% during the aeration stage.

[0044] 4. A linear control of aeration volume is proposed to improve the stability of the sewage treatment process, and a nonlinear control is proposed to improve the applicability of the method.

[0045] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0047] Figure 1 The COD concentration and the COD concentration change rate obtained by the embodiment of the present invention through historical data are as follows;

[0048] Figure 2 The aeration frequency change trend of the present invention and the aeration frequency change trend of the prior art;

[0049] Figure 3 A schematic diagram of the structure of an SBR process aeration control device based on real-time COD monitoring provided by an embodiment of the present invention;

[0050] Figure 4 A flow chart of an SBR process aeration control strategy based on real-time COD monitoring provided by an embodiment of the present invention.

[0051] Reference numerals:

[0052] 1-SBR reactor, 2-COD detection probe, 3-COD analyzer, 4-editable logic controller, 5-frequency converter, 6-blower, 7-valve, 8-aeration pipe. DETAILED DESCRIPTION

[0053] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0054] SBR (Sequencing Batch Reactor Activated Sludge Process) is an activated sludge sewage treatment technology that operates in an intermittent aeration mode. The main sewage treatment processes of SBR include: water intake, aeration, sedimentation, drainage and standby. Among them, aeration refers to the process of forcibly transferring oxygen in the air to the liquid, with the purpose of obtaining sufficient dissolved oxygen to oxidize and decompose the reducing pollutants in the sewage. During the aeration process, SBR uses a constant aeration volume for aeration. However, as time goes by, the reducing pollutants in the water decrease, which will inevitably lead to a decrease in the decomposition rate of the reducing pollutants. At this time, continuing to maintain a constant aeration volume cannot increase the decomposition rate of the reducing pollutants, but instead consumes a lot of energy.

[0055] In order to reduce the energy consumption of SBR during the aeration stage, it is necessary to detect the water quality in real time, and then reduce the aeration volume according to the water quality to reduce the energy consumption of SBR during the aeration process. The parameters commonly used to characterize water quality are COD (Chemical Oxygen Demand) and DO (dissolved oxygen), which are commonly used water quality evaluation parameters. Among them, COD refers to the amount of oxidant consumed by the oxidation of reducing substances in 1 liter of water sample under certain conditions, which is converted into milligrams of oxygen required after all liters of water sample are oxidized, expressed in mg / L. COD reflects the degree of pollution by reducing substances in water. DO refers to the molecular oxygen dissolved in water, which is called dissolved oxygen, usually recorded as DO, expressed in milligrams of oxygen per liter of water. It is an indicator to measure the self-purification ability of water bodies. As can be seen from the definition, there is no direct correlation between the two. In other words, when testing water quality, COD and DO cannot replace each other or be derived from each other.

[0056] When characterizing water quality, DO is easier and faster to measure than COD, so DO measurement is usually used as a reference to adjust the aeration volume. However, DO testing has the following problems:

[0057] On the one hand, during the aeration process, as time goes by, DO continues to increase and COD continues to decrease. However, under certain conditions, the oxygen content in the water will not increase indefinitely. When DO reaches its maximum value, the subsequent DO test results are meaningless. That is, when DO reaches its maximum value, only COD can be tested. The traditional COD test method takes 3-5 hours, and it is obvious that the COD test results at this time have a time lag.

[0058] On the other hand, since there is no necessary quantitative relationship between DO and COD, there is no way to calculate COD through DO during the detection process. That is to say, if COD reaches the preset value before DO, the subsequent aeration is meaningless and will only waste energy and processing time.

[0059] Aiming at the defects of SBR aeration process and the insufficiency of DO measurement method in the prior art, the present invention provides an SBR process aeration control method based on COD real-time monitoring, comprising the following steps:

[0060] Step 1: Collect the current COD concentration, current aeration volume and current aeration time;

[0061] Step 2: Determine the current COD concentration change rate based on the current COD concentration and the current aeration time.

[0062] Step 3: When it is determined that the current COD concentration change rate is not greater than the first COD concentration change rate and greater than the second COD concentration change rate, determine the aeration volume reduction rate.

[0063] In the embodiment of the present invention, the control of aeration volume reduction rate is divided into linear control and nonlinear control.

[0064] Specifically, linear control is divided into single-stage control and multi-stage control.

[0065] The specific process of single-stage control is as follows: according to the preset aeration volume decrease rate range, determine the aeration volume function, which is a linear function with aeration time as the independent variable and aeration volume as the dependent variable. According to the aeration volume function, determine the aeration volume reduction rate. That is, use the linear function as the path for the aeration volume to decrease. Among them, the aeration volume function is a random function within the preset aeration volume decrease rate range; the aeration volume decrease rate range is 10 units per 20min-30min, and the aeration volume decreases by 10 units.

[0066] The specific process of multi-stage control is as follows: determine multiple aeration volume control points, each of which corresponds to an aeration volume to be controlled. According to the preset aeration volume reduction rate range and each aeration volume to be controlled, determine multiple aeration volume functions, each of which is a linear function with aeration time as the independent variable and aeration volume as the dependent variable. According to each aeration volume function, determine the aeration volume reduction rate corresponding to each aeration volume control point. Multi-stage control can make up for the problems of single-end control accuracy and single control mode.

[0067] The content of sewage components is complex, and it is difficult to meet actual needs by simply relying on linear control. For this reason, the embodiment of the present invention uses a nonlinear function to determine the aeration volume reduction rate to achieve nonlinear control. During the nonlinear control process, the aeration volume reduction rate is constantly changing, resulting in the aeration time being difficult to control. In view of the above problems, the embodiment of the present invention sets control targets for nonlinear control, including target time and target aeration volume.

[0068] Specifically, near the end of the aeration phase, due to measurement errors and uneven COD distribution, the measurement results of the COD concentration in the sewage will be inaccurate. In order to avoid the above situation causing sewage treatment to fail to meet standards, when the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration, the current aeration volume is adjusted to the preset aeration volume. The preset aeration volume is also the target aeration volume for nonlinear control. After each aeration process is completed, the time required for the initial aeration volume to become the preset aeration volume is recorded, and then the average value of the recorded time is determined to obtain the target time. It should be noted that the average value of time in the embodiment of the present invention does not only refer to the arithmetic mean, but can also be other averages, such as the weighted average.

[0069] Based on the target aeration volume and target time, the specific process of nonlinear control is:

[0070] Determine a first coordinate according to the current time and the current aeration volume;

[0071] Determine the second coordinate according to the preset aeration volume and target time;

[0072] Generate an aeration volume function according to the first coordinate, the second coordinate and the preset aeration volume decrease rate range, wherein the aeration volume function is a nonlinear function with aeration time as an independent variable and aeration volume as a dependent variable;

[0073] According to the aeration volume function, the aeration volume reduction rate is determined;

[0074] The aeration volume decrease rate ranges from 10 units every 20 minutes to 30 minutes.

[0075] Step 4: reduce the aeration volume according to the aeration volume reduction rate until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration.

[0076] In the embodiment of the present invention, the COD concentration change rate is constantly decreasing, and the reduction process is roughly divided into three stages. In the first stage, the easily decomposable components of COD in the sewage decompose rapidly, and the COD concentration change rate decreases rapidly in this stage; in the second stage, the easily decomposable components of COD in the sewage are basically completely decomposed, and the remaining components continue to decompose, and the COD concentration change rate decreases slowly in this stage; in the third stage, the COD concentration in the sewage reaches the standard concentration (COD target concentration), and the concentration change rate remains basically unchanged.

[0077] Specifically, for easily decomposable COD, the decomposition rate is fast and it also consumes a lot of oxygen, so it is necessary to maintain the oxygen content in the water by ensuring a large aeration volume to achieve rapid decomposition. A large aeration volume needs to be maintained in the first stage.

[0078] The COD concentration change rate can characterize the decomposition rate of COD. Under certain reaction conditions such as temperature and pressure, the decomposition rate of COD is determined by the COD's own properties and concentration. The decomposition rate of easily decomposable COD is obviously faster than that of other components. After the easily decomposable COD is decomposed, the decomposition rate will inevitably have an obvious change. Therefore, the present invention characterizes this change with the first COD concentration change rate, thereby converting this change into data, i.e., the first COD concentration change rate is the dividing point between the first stage and the second stage, so that the aeration amount is controlled.

[0079] In the second stage, the remaining COD continues to decompose. Since the remaining COD is not as active as the easily decomposed COD, its oxygen consumption rate decreases. At this time, it is only necessary to supplement oxygen according to the current oxygen consumption rate. Therefore, the aeration volume should be reduced in the second stage to reduce energy consumption. When the COD concentration reaches the target COD concentration (usually the COD concentration specified in the national standard), the amount of COD is already very small. At this time, its decomposition rate will basically not change, and the aeration volume needs to be maintained at the minimum value. Therefore, the target COD concentration and the second COD concentration change rate are used as the dividing point between the second and third stages, and the transformation of the decomposition rate is digitized again to facilitate the control of the aeration volume.

[0080] It can be seen that the COD target concentration, the first COD concentration change rate and the second COD concentration change rate are very important for the implementation of the present application. The specific process of obtaining the above three values ​​is:

[0081] Step a: Obtain historical sewage treatment data.

[0082] The application scenario of the present invention is SBR. For the same SBR, the type of sewage treated, component content, sewage treatment volume, sewage treatment time, and COD change trend are stable in the long run. Therefore, the historical sewage treatment data include: data on the change of COD concentration in water over time, data on the change rate of COD over time, such as Figure 1 Preferably, the historical sewage treatment data is data of a treatment cycle, and the treatment cycle is in months or years.

[0083] Step b: determining the COD concentration function and the COD change rate function respectively based on historical sewage treatment data.

[0084] In the embodiment of the present invention, the COD concentration function takes the aeration time as the independent variable and the COD concentration as the dependent variable; the COD change rate function takes the aeration time as the independent variable and the COD change rate as the dependent variable. Figure 1 The two sets of data in are fitted to obtain the COD concentration function and COD change rate function respectively.

[0085] Step c: determining a first COD concentration change rate and a second COD concentration change rate respectively according to the COD concentration function and the COD change rate function.

[0086] In the embodiment of the present invention, the COD target concentration is the target concentration to be achieved by sewage treatment as specified in the national standard, so the COD target concentration is fixed. According to the COD target concentration and the time corresponding to the COD target concentration, the second COD concentration change rate is determined by the COD change rate function.

[0087] When determining the first COD concentration change rate, multiple test points are determined through the COD change rate function according to the change trend of the COD concentration function graph, and the aeration volume test is performed for each test point. That is, each test point is used as the first COD concentration change rate for sewage treatment. For each test, when the current COD concentration change rate is determined to be the test point, the aeration volume is reduced until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration. Record the power consumption corresponding to each test point, and select the test point with the smallest power consumption as the first COD concentration change rate.

[0088] It should be noted that the COD concentration function determined according to historical data takes the maximum COD concentration in the historical data as the initial concentration, and the initial concentration in actual operation is usually less than the historical maximum COD concentration. In the embodiment of the present invention, the corresponding COD concentration function in the actual treatment process is regarded as a part of the COD concentration function obtained from the historical data. Therefore, in the actual sewage treatment process, the COD concentration function and the COD change rate function established by the historical data are still used to control the aeration volume. In addition, when the initial concentration of sewage treatment is less than the COD concentration corresponding to the first COD concentration change rate, sewage with a higher COD concentration can be added to ensure that the initial concentration is greater than the COD concentration corresponding to the first COD concentration change rate, so as to facilitate subsequent sewage treatment.

[0089] For sewage treatment enterprises, their electricity consumption is relatively complicated. On the one hand, enterprises need to consider energy conservation and cost reduction, and on the other hand, to ensure the sewage treatment effect, they must use sufficient exhaust volume. In addition, although the components and content of sewage remain unchanged for a long time, the deviation of the component content in sewage from historical data will still occur. In order to deal with the above problems, the present invention sets the aeration volume function as a random function to provide more control methods for aeration volume control. Preferably, for nonlinear control, the aeration volume function and the power consumption corresponding to the aeration volume function are stored; the generation probability of each aeration volume function is determined based on the power consumption; when determining the aeration volume reduction rate, the aeration volume function is generated based on the generation probability, the first coordinate, the second coordinate and the preset aeration volume reduction rate range to minimize the power consumption during the aeration process.

[0090] Preferably, receive external input power consumption control parameters; determine the target power consumption and the optimized aeration volume function corresponding to the target power consumption according to the power consumption control parameters, and the optimized aeration volume function is used to determine the aeration volume reduction rate; control the power consumption during the aeration process not to exceed the target power consumption. For example, the sewage treatment plant limits the current and voltage parameters according to production. According to the above settings, first calculate the power consumption of the aeration process under the current and voltage, and then determine the optimized aeration volume function according to the corresponding relationship between the power consumption and the aeration volume function. In this way, the optimized aeration volume function is used in the aeration stage to determine the aeration volume reduction rate to achieve the purpose of balancing energy saving and production.

[0091] Specifically, Figure 2 As shown, the area below the aeration frequency trend line of the present invention represents the power consumption, wherein the changing trend of the aeration frequency is the same as the changing trend of the aeration volume. Q1 is the aeration volume of the first stage. In the actual process, Q1 is the aeration power of the SBR, Q2 is the aeration volume of the second stage, which is determined by the aeration volume function, and Q3 is the aeration volume of the third stage. As mentioned above, for a certain SBR reactor, Q1 and Q3 are both constants, then the Q1 and Q3 segments of the aeration frequency trend line of the present invention are unchanged. In this way, it is the Q2 segment that determines the power consumption in the present invention, that is, the smaller the corresponding area of ​​the Q2 segment, the smaller the power consumption. In an embodiment of the present invention, the generation probability of the aeration volume function is set according to the power consumption, so that the function with obvious power saving effect is preferentially used to control the aeration volume reduction rate, so that the proportion of reduced power consumption is close to 30%.

[0092] In addition, setting the generation probability for the aeration function can effectively help enterprises reduce the power consumption during the aeration stage, and can flexibly adjust the aeration volume according to actual conditions. For example, during low-peak electricity consumption, enterprises can increase the total aeration volume by changing the generation probability of the random function to improve sewage treatment efficiency. During peak electricity consumption, they can reduce the total aeration volume by changing the generation probability of the random function to reduce energy consumption.

[0093] The embodiment of the present invention provides an SBR process aeration control device based on real-time COD monitoring, such as Figure 3 As shown, it includes: a COD detection probe 2, a COD analyzer 3, an editable logic controller 4, a frequency converter 5 and a blower 6.

[0094] The COD detection probe 2 is arranged in the SBR reactor 1 , and is used to collect the COD concentration signal in the sewage, and send the COD concentration signal to the COD analyzer 3 .

[0095] The COD analyzer 3 determines the aeration volume reduction rate based on the COD concentration signal, when the current COD concentration change rate is not greater than the first COD concentration change rate and is greater than the second COD concentration change rate, until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration, obtains the current aeration volume, and sends the current aeration volume to the editable logic controller 4.

[0096] In the embodiment of the present invention, the COD analyzer 3 uses UV 254 The ultraviolet fluorescence method is used to quickly test COD in sewage, laying a technical foundation for real-time detection of COD.

[0097] The editable logic controller 4 determines the operating parameters of the blower 6 according to the current aeration volume, and controls the blower 6 to operate according to the operating parameters through the frequency converter 5. Specifically, the operating parameters of the blower 6 include the motor speed, and the blower 6 operates according to the motor speed determined by the editable logic controller 4, thereby increasing or decreasing the aeration volume. The gas generated by the blower 6 enters the aeration pipe 8 through the valve 7.

[0098] The embodiment of the present invention provides an SBR process aeration control system based on COD real-time monitoring, comprising: an electric energy meter, a first data processing module and an SBR process aeration control device based on COD real-time monitoring.

[0099] The electric energy meter is used to record the power consumption during the aeration stage of the SBR tank.

[0100] The first data processing module is used to set the generation probability of the aeration volume function generated by the COD analyzer according to the power consumption recorded by the electric energy meter.

[0101] In an embodiment of the present invention, the SBR process aeration control system based on COD real-time monitoring further includes: a second data processing module;

[0102] The second data processing module is used to generate a function of COD concentration changing with time and a function of COD concentration changing rate changing with time according to the historical data of SBR sewage treatment; and determine the first COD concentration changing rate and the second COD concentration changing rate according to the function of COD concentration changing rate changing with time.

[0103] The first data processing module and the second data processing module may be computers.

[0104] The following examples and comparative examples are given to illustrate the feasibility of the embodiments of the present invention.

[0105] Example 1

[0106] The first stage is the water inlet stage: the sewage inlet time is determined according to the water inlet volume. When the sewage enters the SBR reactor and reaches the set time, the water inlet valve of the water inlet pump is closed, and then it enters the second stage.

[0107] The second stage of aeration: the air inlet valve is opened, and the blower is turned on to aerate the SBR reactor. The COD real-time monitoring value and the rate of change per unit time ΔCOD are used as the control index of the aeration volume, and the function y of COD changing with time t is established. COD =F(t), rate of change The process controller and frequency conversion are used to adjust the aeration volume Q of the blower. The control logic is as follows: Figure 4 As shown:

[0108] 1. Set the COD standard value to C0;

[0109] 2. When real-time monitoring of y COD >C0, and ΔCOD≥b, that is, in the stage 0 to T1, the aeration volume of the blower is the initial volume Q1;

[0110] 3. When real-time monitoring of y COD >C0, and a<ΔCOD<b, that is, in the stage T1-T2, the aeration volume Q2 of the blower gradually decreases with the increase of time T, Q2=g(t), g(t) is the aeration volume function. When t→∞ in g(t), the aeration volume Q2=ξ×Q1, where ξ is the setting coefficient, 0<ξ<1.

[0111] 4. When real-time monitoring of y COD ≤C0, and ΔCOD≤a, that is, T2-T3 stage, the aeration volume is Q3=Q2, and aeration is stopped after continuous aeration at Q3 for 30 minutes.

[0112] Then add the carbon source and stir: add the amount of carbon source according to the operating experience, turn on the stirrer and stir according to the set time, and then enter the next stage.

[0113] The third stage is the sedimentation stage: the sedimentation time is set according to the operating experience. When the sedimentation time reaches the set time, it enters the drainage stage.

[0114] The fourth stage is the drainage stage: the treated water is discharged out of the reactor through the outlet pipe; after the drainage is completed, the drainage valve is closed.

[0115] The fifth stage is the idle stage: set a time limit based on the on-site situation to meet the requirements of the next operation cycle. After the idle stage, enter a new cycle.

[0116] Wherein, a corresponds to the second concentration change rate in the embodiment, and b corresponds to the first concentration change rate in the embodiment.

[0117] Comparative Example

[0118] The first stage is the water inlet stage: the sewage inlet time is determined according to the water inlet volume. When the sewage enters the SBR reactor and reaches the set time, the water inlet valve of the water inlet pump is closed, and then it enters the second stage.

[0119] The second stage is aeration: the air inlet valve is opened, and the blower is turned on to aerate the SBR reactor with a constant aeration volume Q1. Then add the carbon source and stir: add the amount of carbon source according to the operating experience, and turn on the stirrer to stir according to the set time, and then enter the next stage.

[0120] The third stage is the sedimentation stage: the sedimentation time is set according to the operating experience. When the sedimentation time reaches the set time, it enters the drainage stage.

[0121] The fourth stage is the drainage stage: the treated water is discharged out of the reactor through the outlet pipe; after the drainage is completed, the drainage valve is closed.

[0122] The fifth stage is the idle stage: set a time limit based on the on-site situation to meet the requirements of the next operation cycle. After the idle stage, enter a new cycle.

[0123] The power consumption of Example 1 is Figure 2 The area below the aeration frequency trend line of the present invention, the power consumption of comparative example 1 is Figure 2 The area below the aeration frequency trend line of the prior art. The area of ​​the shaded area is the power consumption saved in Example 1. It can be seen that the technical solution provided by the present invention can effectively reduce the power consumption during the aeration process.

[0124] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A SBR process aeration control method based on real-time COD monitoring, characterized in that: include: Collect current COD concentration and current aeration time; Determining a current COD concentration change rate according to the current COD concentration and the current aeration time; When it is determined that the current COD concentration change rate is not greater than the first COD concentration change rate and greater than the second COD concentration change rate, determining the aeration volume reduction rate; The aeration amount is reduced according to the aeration amount reduction rate until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration.

2. The method according to claim 1, characterized in that: Determining the aeration volume reduction rate includes: According to a preset aeration volume decrease rate range, an aeration volume function is determined, wherein the aeration volume function is a linear function with aeration time as an independent variable and aeration volume as a dependent variable; The aeration amount reduction rate is determined according to the aeration amount function.

3. The method according to claim 2, characterized in that The aeration volume function is a random function within a preset aeration volume decrease rate range; the aeration volume decrease rate range is that the aeration volume decreases by 10 units every 20 minutes to 30 minutes.

4. The method according to claim 1, characterized in that Determining the aeration volume reduction rate includes: Determine a plurality of aeration volume control points, each of which corresponds to an aeration volume to be controlled; According to the preset aeration volume decrease rate range and each of the aeration volumes to be controlled, a plurality of aeration volume functions are determined, each of the aeration volume functions is a linear function, with aeration time as an independent variable and aeration volume as a dependent variable; According to each of the aeration volume functions, the aeration volume reduction rate corresponding to each of the aeration volume control points is determined.

5. The method according to claim 1, characterized in that The method further comprises: When the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration, the current aeration amount is adjusted to a preset aeration amount.

6. The method according to claim 5, characterized in that The method further comprises: After each aeration process is completed, record the time required for the initial aeration volume to become the preset aeration volume; The average of the recorded times is determined to obtain the target time.

7. The method according to claim 6, characterized in that Determining the aeration volume reduction rate includes: Determine a first coordinate according to the current aeration time and the current aeration amount; Determining a second coordinate according to the preset aeration volume and the target time; Generate an aeration volume function according to the first coordinate, the second coordinate and a preset aeration volume decrease rate range, wherein the aeration volume function is a nonlinear function with aeration time as an independent variable and aeration volume as a dependent variable; Determining the aeration amount reduction rate according to the aeration amount function; The aeration volume reduction rate ranges from 10 units of aeration volume every 20 minutes to 30 minutes.

8. The method according to claim 7, characterized in that storing the aeration amount function and the power consumption corresponding to the aeration amount function; Determining the generation probability of each of the aeration volume functions according to the power consumption; The generating of the aeration amount function comprises: The aeration amount function is generated according to the generation probability, the first coordinate, the second coordinate and a preset aeration amount decrease rate range.

9. An SBR process aeration control device based on real-time COD monitoring, characterized in that: include: COD detection probe, COD analyzer, programmable logic controller, frequency converter and blower; The COD detection probe is arranged in the SBR reactor, and is used to collect the COD concentration signal in the sewage, and send the COD concentration signal to the COD analyzer; The COD analyzer determines the aeration volume reduction rate according to the COD concentration signal when the current COD concentration change rate is not greater than the first COD concentration change rate and greater than the second COD concentration change rate, until the current COD concentration change rate is not greater than the second COD concentration change rate and the current COD concentration is not greater than the COD target concentration, obtains the current aeration volume, and sends the current aeration volume to the editable logic controller; The editable logic controller determines the operating parameters of the blower according to the current aeration amount; The frequency converter is used to control the blower to operate according to the operating parameters.

10. An SBR process aeration control system based on real-time COD monitoring, used to execute the method of claims 1-7, characterized in that: include: An electric energy meter, a second data processing module, a first data processing module and the device according to claim 9; The electric energy meter is used to record the power consumption during the aeration stage of the SBR tank; The first data processing module is used to set the generation probability of the aeration amount function generated by the COD analyzer according to the power consumption recorded by the electric energy meter; The second data processing module is used to generate a function of COD concentration changing over time and a function of COD concentration changing rate changing over time based on the historical data of SBR sewage treatment; and determine the first COD concentration changing rate and the second COD concentration changing rate based on the function of COD concentration changing rate changing over time.

Images