A method for optimizing control of flow promoter in biological pool of AAO process

Abstract

The present invention discloses an AAO process biological pool flowmaker optimization control method, wherein a monitoring system monitors production data collected from a PLC control system in real time, and an optimization algorithm control unit can calculate in real time the minimum number of flowmakers to be opened. The present invention constructs a model of the minimum number of flowmakers required for the normal operation of the biological pool, and then monitors the operating status of the biological pool and the flowmakers in real time through a PLC control system, corrects and optimizes the constructed model, and then configures the operating mode and the best combination mode of the flowmakers in real time; the initial minimum number of flowmakers opened model is corrected and optimized, and each flowmaker in the biological pool is regulated according to the processed minimum number of flowmakers opened model, compared with an AAO control system that does not establish a corresponding energy-saving control model, the energy consumption reduction range is increased, and the purpose of energy saving and consumption reduction is achieved while ensuring that the effluent water quality meets the standard.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to an optimization control method for a flow promoter in an AAO process biological pool. Background Art

[0002] AAO (Anaerobic-Anoxic-Oxic) is a combination of traditional activated sludge process, biological nitrification and denitrification process and biological phosphorus removal process for biological nitrogen and phosphorus removal. It has good removal capacity for BOD, SS and nitrogen and phosphorus in various forms. It is a commonly used urban sewage treatment process. As an important equipment of the biological pool, the flow pusher plays a positive role in promoting the circulation of the mixed liquid in the low-speed area at the bottom of the biological pool, thereby solving the problems of low flow rate and sludge deposition at the bottom of the biological pool, making the water flow more stable, the bubble action time longer, and the microorganisms and mixed liquid more effective. As one of the important sewage treatment equipment, the operating conditions and flow pushing effect of the flow pusher directly affect the treatment quality of sewage.

[0003] At present, relevant researchers mostly optimize the selection of flowmakers, installation location or offset distance between flowmakers and diversion walls, so that flowmakers can operate under optimal conditions, thereby reducing the operating costs of flowmakers. However, at the beginning of the design of flowmakers, in order to cope with complex changes in water quality and water volume, designers will still determine the operating parameters, number of equipment and installation location of flowmakers based on the maximum design load.

[0004] Most sewage treatment plants operate below the design conditions, and the number of flowmakers often exceeds the actual operation requirements. Due to the lack of relevant optimization control solutions, process operators basically control the flowmakers in the biological pools in a fully open and normally open mode. In the actual production process, the sewage treatment volume shows peaks in the morning and evening, during the day, at night, in summer and in winter. The sludge concentration, COD and temperature in the sewage also show seasonal changes. The traditional normally open control mode will generate a lot of energy waste. Most of the existing AAO control systems save energy and reduce consumption by improving equipment, ditch types and other devices. The lack of corresponding energy-saving control models has limited the reduction in energy consumption.

[0005] For example, Chinese patent CN104710010B, published on September 30, 2015, is a real-time control system for AAO oxidation ditch and its sewage treatment method. After denitrification, the mixed liquor in the anoxic tank is returned to the anaerobic tank and anaerobically releases phosphorus together with the raw water, overcoming the influence of nitrate on anaerobic phosphorus release in the traditional AAO process; the mixed liquor in the anaerobic tank, the return sludge in the secondary sedimentation tank and the return nitrification liquid in the oxidation ditch enter the anoxic tank together for denitrification; the mixed liquor in the anoxic tank enters the oxidation ditch, and through regulation, an aerobic-anoxic alternating environment is created, so that simultaneous nitrification and denitrification occur in the ditch, which enhances the denitrification effect; the PLC control system regulates the aeration mode, reflow ratio, etc. in real time according to the signals collected by each online monitoring instrument. This scheme mainly saves energy and reduces consumption by improving hardware equipment such as equipment, ditch type, and device. No energy-saving control model is established for control, and there is a problem of limited energy consumption reduction. Summary of the invention

[0006] The technical problem to be solved by the present invention is that the current AAO oxidation ditch control system has not established a corresponding energy-saving control model, resulting in a limited reduction in energy consumption. An AAO process biological pool flowmaker optimization control method is proposed, which models the minimum number of biological pool flowmakers to be opened, and timely controls the number of flowmakers to be opened according to the operating status of the biological pool and the flowmaker to increase the reduction in energy consumption.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: an AAO process biological pool flow promoter optimization control method, comprising the following steps:

[0008] According to the condition parameters of the biological pool, calculate the energy required for the operation of the biological pool;

[0009] The initial minimum number of flowmakers to be opened is modeled based on the energy required by the bio-pool and the actual power of the flowmakers.

[0010] Modify and optimize the initial model of the minimum number of flowmakers to be opened;

[0011] According to the processed model of the minimum number of flowmakers to be opened, each flowmaker in the biological pool is regulated. After the initial model of the minimum number of flowmakers to be opened is established, the model is corrected once and twice according to the operating status of the biological pool and the flowmaker, so that the model has stronger adaptability and stability.

[0012] Preferably, the condition parameters of the biological pool include the energy required for plug flow per kilogram of liquid and the calculated energy loss of the biological pool. The calculation formula for the energy required for plug flow per kilogram of liquid is:

[0013]

[0014] Among them, ∑ξ is the total local resistance coefficient; F is the water flow area; λ is the resistance coefficient along the way; U is the wetted perimeter of the channel; C is the water flow velocity; L is the centerline length of the biological pool;

[0015] The energy loss calculation formula for the biological pool is:

[0016] W r =H f Q

[0017] Among them, Q is the flow rate passing through the water section in the biological pool per unit time;

[0018] The energy required for the biological pool is calculated as follows:

[0019] W R =W r / η

[0020] Wherein, η is the flow efficiency of the flowmaker.

[0021] Usually ξ=1, λ=0.03, η=60%; if there are n corners, then ∑ξ=n.

[0022] As a preferred option, the initial minimum number of flow boosters to be opened is:

[0023]

[0024] Where P is the actual power of the flow generator, W r The energy required for the biological pool.

[0025] Based on the energy required by the biological pool and the actual power of the flowmakers, the minimum number of flowmakers required to be turned on under normal operation of the biological pool can be preliminarily calculated.

[0026] As a preferred embodiment, the correction process of the initial minimum number of flow boosters to be opened model includes:

[0027] Check the equipment control status of all flow promoters in the biological pool;

[0028] Determine the operating constraints of the flowmaker;

[0029] The number of flow promoters opened T is modified according to the real-time water inflow of the biological pool;

[0030] The real-time operating data is obtained through the PLC control system, and the number of flowmakers opened is corrected again.

[0031] According to the process operation characteristics and the acquired real-time operating data, the combined operation mode of the flowmakers is calculated and the initial minimum number of flowmakers to be opened is corrected.

[0032] As a preferred embodiment, the device control state calculation formula of the flow booster is:

[0033] A 推流器 =(a1, a2, a3...a i ……a n )

[0034] Among them, a i is the operating status of the i-th flow generator;

[0035] The operating constraints of the flow pusher are:

[0036] A i =1

[0037] MIN(A i , A j )≥1

[0038] T0≥MIN(T 设 )

[0039] Among them, MIN(T 设 ) is the minimum number of units designed to be turned on.

[0040] The above operating constraints indicate that the i-th flowmaker should be in the normally open state, and at least one of the i-th and j-th flowmakers should be open.

[0041] As a preferred method, the calculation formula for correcting the number of flow promoters opened T according to the real-time water inflow is:

[0042] K=Q / Q 设

[0043] Among them, Q 实 is the real-time water intake, Q 设 is the designed water inlet.

[0044] The range of K is 0-100%.

[0045] As a preferred method, the number of flow boosters opened is modified by the PLC control system as follows:

[0046]

[0047] Among them, T 修正min S is the minimum number of flow generators in the biological pool after modification and optimization; m MLSS for biological pool; S y is the liquid level of the biological pool; I W is the inlet water temperature; p is the aeration volume; T is the actual number of flow generators in the biological pool; A i is the operating status of the i-th flow generator. The value is 1 when the device is running and 0 when the device is stopped.

[0048] The PLC control system obtains the effluent water quality data and the flow promoter control status in real time, including reading the real-time data of effluent COD, ammonia nitrogen, total phosphorus, total nitrogen, etc. If the effluent water quality meets the effluent water quality standard of the factory, the correction and optimization is completed.

[0049] As a preferred embodiment, the optimization process of the initial minimum number of flow promoters to be opened model includes:

[0050] When there is no water inflow, no water outflow, and the biological pool is inactive, the minimum number of flow promoters to be opened is T 修正min The calculation formula is:

[0051] T 修正min =0;

[0052] When there is no water inflow or outflow and the biological pool is in a state of aeration, the minimum number of flowmakers to be opened is corrected according to the liquid level of the biological pool.

[0053] The minimum number of flow boosters can be set to three levels: K1, K2 and K3. 修正min =K1; in the middle liquid level state, T 修正min =K2; Under high liquid level condition, T 修正min = K3. The PLC control system obtains the liquid level of the biological pool and the control status of the flow generator in real time, and automatically corrects the minimum number of flow generators to be opened, so that the biological pool can operate normally under the state of suffocation.

[0054] The substantial effect of the present invention is as follows: the present invention constructs a model of the minimum number of flowmakers required for the normal operation of the biological pool, and then monitors the influent water quality and water volume of the sewage treatment plant and the biological pool, as well as the operating status of the biological pool and the flowmakers in real time through a PLC control system, corrects and optimizes the constructed model, and then configures the operating mode and the best combination of the flowmakers in real time; the initial model of the minimum number of flowmakers opened is corrected and optimized, and each flowmaker in the biological pool is regulated according to the processed model of the minimum number of flowmakers opened. Compared with an AAO control system for which a corresponding energy-saving control model is not established, the energy consumption reduction rate is increased, and the purpose of energy saving and consumption reduction is achieved while ensuring that the effluent water quality meets the standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the planar structure of the AAO process biological pool of this embodiment;

[0056] Figure 2 The flowchart of the AAO process biological pool flow pusher optimization control method of this embodiment;

[0057] Figure 3 This is a schematic diagram of the architecture for implementing the optimized control method for the AAO process biological pool flow promoter of this embodiment.

[0058] Among them: A, anaerobic tank, B1, 1# anoxic tank, B2, 2# anoxic tank, B3, 3# anoxic tank, C1, 1# aerobic tank, C2, 2# aerobic tank, C3, 3# aerobic tank, D, mixed liquor return, E, sludge return, F, influent, G, effluent, H, flowmaker, 1, monitoring system, 2, PLC control system, 3, optimization control algorithm unit, 4, MLSS measuring instrument, 5, flow meter, 6, liquid level meter, 7, flowmaker status. DETAILED DESCRIPTION

[0059] The specific implementation of the present invention will be further described below through specific examples in conjunction with the accompanying drawings.

[0060] The planar structure of the biological pool in this embodiment is as follows Figure 1 As shown, after pretreatment, the wastewater enters the anaerobic tank A as influent F and passes through the anaerobic reactor to partially decompose the high COD substances, and then enters the anoxic section, including 1# anoxic tank B1, 2# anoxic tank B2 and 3# anoxic tank B3, for denitrification, followed by the aerobic section for oxidative degradation of organic matter and nitrification, namely 1# aerobic tank C1, 2# aerobic tank C2 and 3# aerobic tank C3. To ensure the efficiency of denitrification, part of the effluent from the aerobic section enters the anoxic stage through reflux and is mixed with the effluent from the anaerobic section to reflux the mixed liquid D to supplement the carbon source in the anoxic section. The other part of the effluent G enters the secondary sedimentation tank, and after separating the activated sludge, it is returned to the anaerobic section as sludge E. Among them, the flow promoter H plays a positive role in promoting the circulation of the mixed liquid in the low-speed zone at the bottom of the tank, preventing sludge sedimentation and substandard effluent water quality.

[0061] A method for optimizing the control of a flow promoter in an AAO process biological pool, such as Figure 2 As shown, the following steps are included:

[0062] According to the condition parameters of the biological pool, calculate the energy required for the operation of the biological pool;

[0063] The initial minimum number of flowmakers to be opened is modeled based on the energy required by the bio-pool and the actual power of the flowmakers.

[0064] Modify and optimize the initial model of the minimum number of flowmakers to be opened;

[0065] The flowmakers in the biological pool are regulated according to the treated minimum opening number model of the flowmakers.

[0066] The specific workflow of this embodiment is as follows:

[0067] 1. Calculate the energy required for the operation of the biological pool based on the medium and pool type parameters of the biological pool.

[0068] The energy required for pushing flow per kilogram of liquid is:

[0069]

[0070] The energy loss of the biological pool is calculated as:

[0071] W r =H f Q (2)

[0072] The energy required for the biological pool is:

[0073] W R =W r / η (3)

[0074] Where, in formula (1), ∑ξ is the total local resistance coefficient, ξ=1. If there are n corners, then ∑ξ=n, and F is the water flow area, m 2 ; λ is the resistance coefficient along the way, λ = 0.03; U is the wetted perimeter of the channel, m; C is the water velocity, m / s; L is the centerline length of the biological pool, m; in formula (2), Q is the flow rate per unit time passing through the water section in the biological pool, m 3 / s; in formula (3), η is the flow-pushing efficiency of the flow-pushing device, η=60%;

[0075] 2. Given the energy required by the bio-pool and the actual power of the flow generator, calculate the minimum number of flow generators required for the normal operation of the bio-pool.

[0076] The minimum number of flow boosters to be opened is:

[0077]

[0078] Where, P in formula (4) is the actual power of the flow generator, W r The energy required for the biological pool.

[0079] 3. According to the process operation characteristics and the real-time operating data obtained, the operation combination mode of the flowmakers is calculated, and the minimum number of flowmakers to be opened is corrected and optimized.

[0080] 1) Check the equipment control status of all flow machines in the biological pool to see if they are controllable.

[0081] A 推流器 =(a1, a2, a3...a i ......a n ) (5)

[0082] Among them, a in formula (5) i is the operating status of the i-th flowmaker.

[0083] 2) Determine the operating constraints of the corresponding flow generator according to the process operation characteristics

[0084] A i =1 (6)

[0085] MIN(A i , A j )≥1 (7)

[0086] T0≥MIN(T 设 ) (8)

[0087] Among them, MIN(T 设 ) is the minimum number of flowmakers to be opened, formula (6) indicates that the i-th flowmaker should be in the normally open state, and formula (7) indicates that at least one of the i-th and j-th flowmakers should be opened.

[0088] 3) According to the real-time water inflow Q of the biological pool 实 Correct the number of flow boosters opened T;

[0089] Real-time collection of water inflow Q of the biological pool 实 , calculate the real-time water inflow Q 实 Q 设 Relationship:

[0090] K=Q 实 / Q 设 (9)

[0091] The range of K is 0-100%, and the relationship between the water inflow and the number of flowmakers opened is shown in Table 1.

[0092] Table 1 Relationship between water inflow and number of flow generators opened

[0093] K 0-a％ a%-b% c%-d% … i%-j% … n％-100％ Number of units <![CDATA[T1]]> <![CDATA[T2]]> <![CDATA[T3]]> … <![CDATA[T i ]]> … T

[0094] Among them, T>T i >…>T3>T2>T1>T0≥MIN(T 设 ).

[0095] 4) The PLC control system obtains real-time operating data to further correct the number of flow promoters that are turned on: including real-time reading of the total inlet flow, temperature, MLSS, pH and effluent COD, ammonia nitrogen, total phosphorus, total nitrogen of the sewage treatment plant, as well as the liquid level, MLSS, aeration volume, and operating status of the mixer of the biological pool.

[0096]

[0097] Among them, T in formula (10) 修正min S is the minimum number of flow generators in the biological pool after modification and optimization. m MLSS for biological pool, S y is the liquid level of the biological pool, IW is the inlet water temperature, I p is the aeration volume, T in formula (11) is the actual number of flow generators in the biological pool, A i is the operating status of the i-th flow generator. The value is 1 when the device is running and 0 when the device is stopped.

[0098] 5) The PLC control system obtains the effluent water quality data and the flow promoter control status in real time, including reading the real-time data of effluent COD, ammonia nitrogen, total phosphorus, total nitrogen, etc. If the effluent water quality meets the effluent water quality standard of the plant, the correction and optimization is completed.

[0099] 4. Optimize the model of minimum number of flowmakers opened under extreme mode conditions.

[0100] 1) When there is no water inflow or outflow and the biological pool is inactive, the minimum number of flow promoters to be opened is T 修正min for:

[0101] T 修正min =0

[0102] 2) There is no water inflow or outflow, and the biological pool is in a state of exposure. The minimum number of flow promoters to be opened is corrected according to the liquid level of the biological pool.

[0103] The PLC control system obtains the liquid level of the biological pool and the control status of the flowmaker in real time. Three gears can be set to automatically correct the minimum number of flowmakers to be opened, so that the biological pool can operate normally even in the muffled exposure state.

[0104] In low liquid level state, T 修正min =K1;

[0105] Under the medium liquid level condition, T 修正min =K2;

[0106] Under high liquid level condition, T 修正min =K3.

[0107] This embodiment includes a monitoring system, such as Figure 3 As shown, the monitoring system 1 monitors in real time the flowmaker status 7, the operating status of the biological pool equipment, the operating parameters, and the production data such as flow, water level, and water quality collected from the PLC control system 2, which can be collected through measuring equipment such as the MLSS measuring instrument 4, the flow meter 5, and the liquid level meter 6. Based on these production data, the optimization algorithm control unit 3 can calculate in real time the minimum number of flowmakers to be opened and configure the corresponding flowmaker operation mode in real time.

[0108] In this embodiment, a model of the minimum number of flowmakers required for the normal operation of the biological pool is constructed, and then the influent water quality and water volume of the sewage treatment plant and the biological pool, as well as the operating status of the biological pool and the flowmakers are monitored in real time through the PLC control system, and the constructed model is corrected and optimized, and the operating mode and the best combination of the flowmakers are configured in real time; the initial model of the minimum number of flowmakers opened is corrected and optimized, and each flowmaker in the biological pool is regulated according to the processed model of the minimum number of flowmakers opened. Compared with the AAO control system for which the corresponding energy-saving control model is not established, the energy consumption reduction is improved, and the purpose of energy saving and consumption reduction is achieved while ensuring that the effluent water quality meets the standard.

[0109] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. An AAO process biological pool flow promoter optimization control method, characterized in that: The steps include: The energy required for the operation of the biological pool is calculated according to the condition parameters of the biological pool, wherein the condition parameters of the biological pool include the energy required for plugging flow per kilogram of liquid and the calculated energy loss of the biological pool, the calculated energy loss of the biological pool is the product of the energy required for plugging flow per kilogram of liquid and the flow rate passing through the water section in the biological pool per unit time, the energy required by the biological pool is the ratio of the calculated energy loss of the biological pool to the plugging efficiency of the flow plug, and the initial minimum number of flow plugs to be opened is the ratio of the energy required by the biological pool to the actual power of the flow plug; The initial minimum number of flowmakers to be opened is modeled based on the energy required by the bio-pool and the actual power of the flowmakers. Modify and optimize the initial model of the minimum number of flowmakers to be opened; The flowmakers in the biological pool are regulated according to the treated minimum opening number model of the flowmakers.

2. The AAO process biological pool flow promoter optimization control method according to claim 1, characterized in that: The condition parameters of the biological pool include the energy required for plug flow per kilogram of liquid and the calculated energy loss of the biological pool. The calculation formula for the energy required for plug flow per kilogram of liquid is: Among them, ∑ξ is the total local resistance coefficient; F is the water flow area; λ is the resistance coefficient along the way; U is the wetted perimeter of the channel; C is the water flow velocity; L is the centerline length of the biological pool; The energy loss calculation formula for the biological pool is: W r =H f Q Among them, Q is the flow rate passing through the water section in the biological pool per unit time; The energy required for the biological pool is calculated as follows: W R =W r / or Wherein, η is the flow efficiency of the flowmaker.

3. The AAO process biological pool flow promoter optimization control method according to claim 2 is characterized in that: The initial minimum number of flow boosters to be turned on is: Where P is the actual power of the flow generator, W R is the energy required for the biological pool, ∑ξ is the total local resistance coefficient; F is the water flow area; λ is the along-the-way resistance coefficient; U is the wetted perimeter of the channel; C is the water flow velocity; L is the centerline length of the biological pool, Q is the flow rate passing through the water flow section in the biological pool per unit time, η is the flow efficiency of the flow generator, ∑ξ=n.

4. The AAO process biological pool flow promoter optimization control method according to claim 3 is characterized in that: The correction process of the initial minimum number of flowmakers model includes: Check the equipment control status of all flow promoters in the biological pool; Determine the operating constraints of the flow booster; The number of flow promoters opened T is modified according to the real-time water inflow of the biological pool; The real-time operating data is obtained through the PLC control system, and the number of flowmakers opened is corrected again.

5. The AAO process biological pool flow promoter optimization control method according to claim 4 is characterized in that: The equipment control state calculation formula of the flow booster is: <h2 style=";text-align:left;direction:ltr">A<h2 style=";text-align:left;direction:ltr"> 推流器 <h2 style=";text-align:left;direction:ltr"> (a1, a2, a3, etc.)<h2 style=";text-align:left;direction:ltr"> i <h2 style=";text-align:left;direction:ltr"> ......a<h2 style=";text-align:left;direction:ltr"> q <h2 style=";text-align:left;direction:ltr"> ) Among them, a i is the operating status of the i-th flow generator; The operating constraints of the flow pusher are: A i ＝1 MIN(A i ,IN j )≥1 T0≥MIN(T 设 ) Among them, MIN(T 设 ) is the minimum number of units opened in the design, T0 is the initial minimum number of units opened for the flow generator, A i It is the operating state of the flow generator under controllable state.

6. The AAO process biological pool flow promoter optimization control method according to claim 4 or 5, characterized in that: The calculation formula for correcting the number of flow boosters opened T according to the real-time water inflow is: K=Q 实 / Q 设 Among them, Q 实 is the real-time water intake, Q 设 is the designed water inlet.

7. The AAO process biological pool flow promoter optimization control method according to claim 4 or 5, characterized in that: The correction form of the number of flow boosters opened by the PLC control system is: Among them, T 修正min S is the minimum number of flow generators in the biological pool after modification and optimization; m MLSS for biological pool; S y is the liquid level of the biological pool; I w is the inlet water temperature; p is the aeration volume; T is the actual number of flow generators in the biological pool; A i is the operating status of the i-th flow generator. The value is 1 when the device is running and 0 when the device is stopped.

8. The AAO process biological pool flow promoter optimization control method according to claim 1 or 4, characterized in that: The optimization process of the initial minimum number of flow-producers model includes: When there is no water inflow, no water outflow, and the biological pool is inactive, the minimum number of flow promoters to be opened is T 修正min The calculation formula is: T 修正min ＝0； When there is no water inflow or outflow and the biological pool is in a state of aeration, the minimum number of flowmakers to be opened is corrected according to the liquid level of the biological pool.

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