Automatic control system and method for nitrogen removal in five-stage bardenpho sewage treatment process

Abstract

The application relates to a five-section Bardenpho sewage treatment process denitrification automatic control system and method, the five-section Bardenpho sewage treatment process is realized based on multiple reaction pools, the automatic control system comprises a controller, the controller controls the denitrification efficiency of the five-section Bardenpho sewage treatment process by regulating and controlling the control parameters of regulating and controlling components arranged on the multiple reaction pools; the regulating and controlling components comprise: an internal reflux pipeline connected to the tail end of a front aerobic tank and the front end of a front anoxic tank; a dosing pipeline, the output end of which is connected to a rear anoxic tank; the controller is in communication connection with the internal reflux pipeline and the dosing pipeline respectively, and is used for controlling the internal reflux ratio of the internal reflux pipeline and the amount of carbon source added into the rear anoxic tank. Based on the system, the regulating and controlling means corresponding to each coupling reaction zone is single, the denitrification effect generated by each regulating and controlling means is more accurate, and thus independent fine control can be carried out, so that the denitrification efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, and in particular to a denitrification automatic control system of a five-stage Bardenpho sewage treatment process and a denitrification automatic control method of the five-stage Bardenpho sewage treatment process. BACKGROUND

[0002] The five-stage Bardenpho process is a commonly used sewage treatment process in urban sewage treatment plants, has the advantages of high denitrification rate and flexible regulation and control, and realizes the removal of organic matter, nitrogen and phosphorus through microbial reactions in different regions. Although the five-stage Bardenpho process performs well in improving the sewage treatment effect, with the fluctuation of the influent water quality and the increase in the complexity of the treatment process, the traditional control method is difficult to meet the dynamic needs in actual operation.

[0003] Specifically, the five-stage Bardenpho process includes an anaerobic tank, a front anoxic tank, a front aerobic tank, a rear anoxic tank and a rear aerobic tank connected in sequence, the material transfer and microbial reaction between each reaction tank are coupled with each other, the control variables are multiple and interact with each other, the existing control strategy usually regards the front anoxic tank and the front aerobic tank as a coupled reaction zone, and regards the rear anoxic tank and the rear aerobic tank as a coupled reaction zone, for each coupled reaction zone, the denitrification effect of the coupled reaction zone is adjusted by adjusting the internal reflux ratio and the amount of carbon source. However, in actual application, the denitrification effects produced by the internal reflux ratio and the amount of carbon source are coupled, which makes it difficult to independently and finely control the two regulation and control means of the internal reflux ratio and the amount of carbon source.

[0004] In addition, the prior art relies on manual experience to adjust the internal reflux ratio and the amount of carbon source, the control method is relatively rough, cannot respond to the fluctuation of the influent water quality in real time, causes large fluctuation of the nitrate nitrogen concentration in the anoxic tank, and affects the denitrification efficiency, especially the regulation and control of the amount of carbon source, which is usually based on a fixed ratio or experience, and is easy to cause waste of carbon source or insufficient removal of nitrate nitrogen. When the influent water quality or water quantity suddenly changes, the regulation and control method relying on manual experience also has a regulation and control lag, which is easy to cause the effluent TN to exceed the standard. SUMMARY

[0005] (1) Technical problem to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present application provides a denitrification automatic control system of a five-stage Bardenpho sewage treatment process and a denitrification automatic control method of the five-stage Bardenpho sewage treatment process, which solves the problem that the prior art cannot finely control the two regulation and control means of the internal reflux ratio and the amount of carbon source.

[0007] (2) Technical solution

[0008] In order to achieve the above-mentioned purpose, the main technical scheme adopted by the present application includes:

[0009] In a first aspect, the embodiments of the present application provide a five-stage Bardenpho sewage treatment process automatic nitrogen removal control system, the five-stage Bardenpho sewage treatment process is realized based on a plurality of reaction tanks, the reaction tanks include an anaerobic tank, a front anoxic tank, a front aerobic tank, a rear anoxic tank and a rear aerobic tank connected in sequence, the automatic control system includes a controller, the controller controls the nitrogen removal efficiency of the five-stage Bardenpho sewage treatment process through a regulation and control component arranged on the plurality of reaction tanks; the regulation and control component includes:

[0010] an internal reflux pipeline connected to the end of the front aerobic tank and the front end of the front anoxic tank, used for refluxing part of sewage at the end of the front aerobic tank to the front end of the front anoxic tank;

[0011] a dosing pipeline with an output end connected to the rear anoxic tank, used for adding a carbon source to the rear anoxic tank;

[0012] the controller is in communication connection with the internal reflux pipeline and the dosing pipeline, respectively, used for controlling the internal reflux ratio of the internal reflux pipeline according to the first nitrate nitrogen concentration at the end of the front anoxic tank and the second nitrate nitrogen concentration at the front end of the rear anoxic tank, and controlling the amount of the carbon source added to the rear anoxic tank according to the second nitrate nitrogen concentration at the front end of the rear anoxic tank, the organic nitrogen concentration at the end of the rear anoxic tank, the ammonia nitrogen concentration at the end of the rear anoxic tank and a preset internal control concentration value of the effluent TN of the water plant.

[0013] Optionally, the controller includes a first judgment module and an internal reflux control module.

[0014] the first judgment module is used for judging whether the current first nitrate nitrogen concentration is in a preset control interval in each adjustment period, and if not, jumping to the internal reflux control module;

[0015] the internal reflux control module is used for calculating the reflux nitrate nitrogen concentration of the reflux sewage of the internal reflux pipeline, and calculating a target adjustment amount of the first nitrate nitrogen concentration; and determining an adjusted internal reflux ratio according to the reflux nitrate nitrogen concentration and the target adjustment amount.

[0016] Optionally, in the internal reflux control module, calculating the current reflux nitrate nitrogen concentration of the reflux sewage of the internal reflux pipeline, and calculating the target adjustment amount of the first nitrate nitrogen concentration, includes:

[0017] taking the product of the current internal reflux ratio and the second nitrate nitrogen concentration as the current reflux nitrate nitrogen concentration;

[0018] taking the difference between the current first nitrate nitrogen concentration and a preset internal control value of the first nitrate nitrogen concentration as the target adjustment amount.

[0019] Optionally, in the internal reflux control module, the adjusted internal reflux ratio is determined according to the internal reflux nitrate nitrogen concentration and the target adjustment amount, comprising:

[0020] a difference between the current internal reflux nitrate nitrogen concentration and a target adjustment amount multiplied by (1+r) is taken as a first proportional factor, wherein r is an external reflux ratio of the five-stage Bardenpho sewage treatment process;

[0021] a sum of the current second nitrate nitrogen concentration and the target adjustment amount is taken as a second proportional factor;

[0022] a ratio of the first proportional factor to the second proportional factor is taken as the adjusted internal reflux ratio.

[0023] Optionally, the controller further comprises a second judgment module and a dosing control module;

[0024] the second judgment module is configured to determine, in each adjustment period, whether the current second nitrate nitrogen concentration is greater than an internal control value of the third nitrate nitrogen concentration at the end of the post-anoxic tank, and if so, jump to the dosing control module;

[0025] the dosing control module is configured to determine, according to the second nitrate nitrogen concentration, the organic nitrogen concentration at the end of the post-anoxic tank, the ammonia nitrogen concentration at the end of the post-anoxic tank, and a preset internal control concentration value of the water plant effluent TN, a target removal amount of nitrate nitrogen in the post-anoxic tank; and determine, according to the target removal amount, a target carbon source amount to be added to the post-anoxic tank.

[0026] Optionally, in the dosing control module, the target removal amount of nitrate nitrogen in the post-anoxic tank is determined according to the second nitrate nitrogen concentration, the organic nitrogen concentration at the end of the post-anoxic tank, the ammonia nitrogen concentration at the end of the post-anoxic tank, and the preset internal control concentration value of the water plant effluent TN, comprising:

[0027] the preset internal control concentration value of the water plant effluent TN is sequentially subtracted by the current ammonia nitrogen concentration at the end of the post-anoxic tank and the organic nitrogen concentration at the end of the post-anoxic tank to obtain a basic target value;

[0028] a difference between the current second nitrate nitrogen concentration and the basic target value is taken as the target removal amount of nitrate nitrogen in the post-anoxic tank.

[0029] Optionally, in the dosing control module, the target carbon source amount to be added to the post-anoxic tank is determined according to the target removal amount, comprising:

[0030] a product of the target removal amount and a carbon source equivalent required for a unit of carbon source to remove nitrate nitrogen is divided by a concentration of the carbon source agent used to obtain a theoretical agent amount, and a sum of an agent compensation amount required to eliminate dissolved oxygen in the post-anoxic tank and the theoretical agent amount is taken as the target carbon source amount.

[0031] Optionally, the controller further comprises:

[0032] a dynamic correction module, configured to compensate and adjust the target carbon source amount according to the following formula based on the current influent flow of the water plant in each adjustment period, to determine the final carbon source amount added to the back anoxic tank:

[0033]

[0034] wherein C f represents the final carbon source amount added to the back anoxic tank;

[0035] C g represents the target carbon source amount added to the back anoxic tank;

[0036] Q0represents the current influent flow of the water plant;

[0037] Q 设计 represents the design influent flow of the water plant;

[0038] a represents a correction coefficient, and the value range is [0.1, 0.7].

[0039] Optionally, the control assembly further comprises:

[0040] an internal reflux pump and an internal reflux flow meter arranged on the internal reflux pipeline; and / or,

[0041] a carbon source container, a metering pump and a dosing pump arranged on the dosing pipeline; and / or,

[0042] an influent flow meter arranged at the front end of the front aerobic tank; and / or,

[0043] a first nitrate nitrogen concentration meter arranged at the end of the front anoxic tank; and / or,

[0044] a second nitrate nitrogen concentration meter arranged at the front end of the back anoxic tank; and / or,

[0045] an ammonia nitrogen concentration meter arranged at the end of the back anoxic tank.

[0046] In a second aspect, the embodiments of the present application provide a nitrogen removal automatic control method of a five-stage Bardenpho sewage treatment process, which is based on the nitrogen removal automatic control system of the five-stage Bardenpho sewage treatment process of the first aspect, and controls the nitrogen removal efficiency of the five-stage Bardenpho sewage treatment process.

[0047] (III) Advantages

[0048] The beneficial effects of the present application are: the denitrification automatic control system of the present application comprises an internal reflux pipeline and a dosing pipeline. The internal reflux pipeline is connected to the end of the front aerobic tank and the front end of the front anoxic tank, and is used for refluxing part of the wastewater at the end of the front aerobic tank to the front end of the front anoxic tank. The dosing pipeline is connected to the rear anoxic tank at the output end, and is used for adding carbon source to the rear anoxic tank. That is, the front coupling reaction zone formed by the front anoxic tank and the front aerobic tank controls the denitrification effect through the internal reflux ratio, and the rear coupling reaction zone formed by the rear anoxic tank and the rear aerobic tank controls the denitrification effect through the amount of carbon source added. The corresponding regulation and control means of each coupling reaction zone is single, and the denitrification effect produced by each regulation and control means is more accurate and clear, so that independent fine control can be performed respectively, thereby improving the denitrification efficiency.

[0049] In addition, the controller used in the denitrification automatic control system of the present application controls the internal reflux ratio of the internal reflux pipeline according to the first nitrate nitrogen concentration at the end of the front anoxic tank and the second nitrate nitrogen concentration at the front end of the rear anoxic tank; and controls the amount of carbon source added to the rear anoxic tank according to the second nitrate nitrogen concentration at the front end of the rear anoxic tank, the organic nitrogen concentration at the end of the rear anoxic tank, the ammonia nitrogen concentration at the end of the rear anoxic tank, and the preset internal control concentration value of the water plant effluent TN. The denitrification control system of the present application can dynamically adjust the internal reflux ratio of the internal reflux pipeline and the amount of carbon source added to the rear anoxic tank respectively and accurately based on the respective independent pipelines according to the changes of the above parameters of each reaction tank, thereby improving the denitrification efficiency and reducing the carbon source consumption. At the same time, both are independently regulated and controlled, and the nitrate nitrogen concentrations of the wastewater flowing through the front coupling reaction zone and the rear coupling reaction zone in each adjustment period are cooperatively controlled, so as to maximize the denitrification efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 A connection schematic diagram of a reaction tank for implementing a five-stage Bardenpho sewage treatment process and a regulation and control assembly provided thereon is provided in the embodiment;

[0051] Figure 2 An architecture schematic diagram of the controller provided in the embodiment is provided;

[0052] Figure 3 Another connection schematic diagram of a reaction tank for implementing a five-stage Bardenpho sewage treatment process and a regulation and control assembly provided thereon is provided in the embodiment. DETAILED DESCRIPTION

[0053] In order to better explain the present application and facilitate understanding, the present application will be described in detail in combination with the drawings and specific embodiments.

[0054] To better understand the above technical solutions, exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application can be understood more clearly and thoroughly, and that the scope of this application can be fully conveyed to those skilled in the art.

[0055] Example 1

[0056] This embodiment provides an automatic denitrification control system for a five-stage Patonpo wastewater treatment process, such as... Figure 1 As shown, the five-stage Patonpo wastewater treatment process is based on multiple reaction tanks, each comprising an anaerobic tank, a pre-anoxic tank, a pre-aerobic tank, a post-anoxic tank, and a post-aerobic tank connected in sequence. The automatic control system includes a controller, which regulates the denitrification efficiency of the five-stage Patonpo wastewater treatment process through control components installed on the multiple reaction tanks. The control components include:

[0057] The internal return pipe connects the end of the front aerobic tank and the front of the front anoxic tank, and is used to return a portion of the wastewater from the end of the front aerobic tank to the front of the front anoxic tank.

[0058] The dosing pipeline has its output end connected to the post-anoxic tank and is used to add carbon source to the post-anoxic tank.

[0059] Specifically, the internal reflux pipeline is equipped with an internal reflux pump and an internal reflux flow meter; the dosing pipeline is equipped with a carbon source container, a metering pump, and a dosing pump; the front end of the front aerobic tank is equipped with an influent flow meter; the end of the front anoxic tank is equipped with a first nitrate nitrogen concentration meter; the front end of the rear anoxic tank is equipped with a second nitrate nitrogen concentration meter; and the end of the rear anoxic tank is equipped with an ammonia nitrogen concentration meter.

[0060] The controller is communicatively connected to the internal return pipeline and the dosing pipeline, and is used to control the internal return ratio of the internal return pipeline according to the first nitrate nitrogen concentration at the end of the front anoxic tank and the second nitrate nitrogen concentration at the front of the rear anoxic tank; and to control the amount of carbon source added to the rear anoxic tank according to the second nitrate nitrogen concentration at the front of the rear anoxic tank, the organic nitrogen concentration at the end of the rear anoxic tank, the ammonia nitrogen concentration at the end of the rear anoxic tank, and the preset internal control concentration value of TN in the water plant effluent.

[0061] Based on the above setting mode, the coupling reaction zone formed by the front anoxic tank and the front aerobic tank of the present application controls the denitrification effect through the internal reflux ratio, and the coupling reaction zone formed by the rear anoxic tank and the rear aerobic tank of the present application controls the denitrification effect through the amount of carbon source added. The corresponding regulation means of each coupling reaction zone is single, and the denitrification effect generated by each regulation means is more accurate and clear, so that independent fine control can be performed respectively, thereby improving the denitrification efficiency.

[0062] Embodiment Two

[0063] In order to better understand Embodiment One, the specific architecture of the controller is described in detail in this embodiment.

[0064] As shown in Figure 2 The controller provided by the present embodiment comprises a first judgment module, an internal reflux control module, a second judgment module and a dosing control module.

[0065] The judgment module is configured to judge whether the first nitrate nitrogen concentration is within a preset control interval in each adjustment period. If not, jump to the internal reflux control module. If yes, it indicates that the current first nitrate nitrogen concentration does not need to be adjusted, and the internal reflux ratio does not need to be adjusted in the current adjustment period.

[0066] Specifically, the preset control interval is determined according to the specific equipment and design data of the water plant, and generally needs to be set in a reasonable low range to ensure that the effluent TN value of the water plant is less than the specified discharge standard.

[0067] The internal reflux control module is configured to calculate the reflux nitrate nitrogen concentration of the reflux sewage of the internal reflux pipeline, and calculate the target adjustment amount of the first nitrate nitrogen concentration; and determine the adjusted internal reflux ratio according to the reflux nitrate nitrogen concentration and the target adjustment amount.

[0068] The second judgment module is configured to judge whether the current second nitrate nitrogen concentration is greater than the internal control value of the third nitrate nitrogen concentration at the end of the rear anoxic tank in each adjustment period. If yes, jump to the dosing control module. Specifically, the internal control concentration value of the third nitrate nitrogen concentration is generally determined according to the internal control concentration of the effluent TN of the water plant; preferably, the internal control concentration value of the third nitrate nitrogen concentration is the difference between the internal control concentration of the effluent TN of the water plant and the current ammonia nitrogen concentration at the end of the rear anoxic tank and the organic nitrogen concentration at the end of the rear anoxic tank.

[0069] The dosing control module determines the target removal amount of nitrate nitrogen in the rear anoxic tank according to the second nitrate nitrogen concentration and the ammonia nitrogen concentration at the end of the rear anoxic tank; and determines the target carbon source amount added to the rear anoxic tank according to the target removal amount.

[0070] The adjustment period refers to the time interval for the denitrification automatic control system to adjust the control parameters of the control component each time. Specifically, the adjustment period can be 5 minutes to 3 hours, preferably, the adjustment period is 30 minutes to 2 hours, and most preferably, the adjustment period is 1 hour.

[0071] In a specific embodiment of the present embodiment, the specific manner in which the internal reflux control module adjusts the internal reflux pipeline is as follows:

[0072] The product of the current internal reflux ratio and the second nitrate nitrogen concentration is taken as the current reflux nitrate nitrogen concentration.

[0073] The difference between the current first nitrate nitrogen concentration and the preset internal control value of the first nitrate nitrogen concentration is taken as the target adjustment amount.

[0074] The difference between the current reflux nitrate nitrogen concentration and the target adjustment amount multiplied by (1+r) is taken as the first proportion factor; wherein r is the external reflux ratio of the five-stage Bardenpho sewage treatment process.

[0075] The sum of the current second nitrate nitrogen concentration and the target adjustment amount is taken as the second proportion factor.

[0076] The ratio of the first proportion factor to the second proportion factor is taken as the adjusted internal reflux ratio.

[0077] Preferably, the preset internal control value of the first nitrate nitrogen concentration can be determined according to the preset control interval of the first nitrate nitrogen concentration, which can specifically be the middle value of the preset control interval of the first nitrate nitrogen concentration. For example, if the preset control interval of the first nitrate nitrogen concentration is [A, B], the preset internal control value of the first nitrate nitrogen concentration is (A+B) / 2. That is, when the current first nitrate nitrogen concentration is lower than A, the internal reflux ratio is increased to increase the current first nitrate nitrogen concentration to a value close to (A+B) / 2 within the control interval [A, B]. When the current first nitrate nitrogen concentration is higher than B, the internal reflux ratio is decreased to decrease the current first nitrate nitrogen concentration to a value close to (A+B) / 2 within the control interval [A, B]. In this way, the internal reflux ratio is increased / decreased to make the first nitrate nitrogen concentration instrument online value return to a position close to the middle value within the control interval.

[0078] The inner reflux pipeline is connected to the end of the front aerobic tank and the front end of the front anoxic tank, that is, the two ends of the front coupled reaction zone composed of the front anoxic tank and the front aerobic tank, for refluxing part of the wastewater at the end of the front aerobic tank to the front end of the front anoxic tank. The inner reflux control module takes the deviation of the current first nitrate nitrogen concentration at the end of the front anoxic tank from the internal control value as the target adjustment amount, and adjusts the inner reflux ratio of the inner reflux pipeline based on the second nitrate nitrogen concentration at the front end of the back anoxic tank (that is, the end of the front aerobic tank). The first nitrate nitrogen concentration and the second nitrate nitrogen concentration involved in the adjustment of the inner reflux ratio are both control parameters of the front coupled reaction zone composed of the front anoxic tank and the front aerobic tank, and the overall calculation process does not involve the control parameters of the back coupled reaction zone composed of the back anoxic tank and the back aerobic tank. Therefore, the adjustment of the inner reflux ratio as a control means can independently control the denitrification effect of the front coupled reaction zone, thereby achieving fine control of the front coupled reaction zone. Moreover, based on the deviation of the current first nitrate nitrogen concentration from the internal control value, the application can dynamically adjust the inner reflux ratio, stabilize the fluctuation range of the first nitrate nitrogen concentration, and simultaneously improve the denitrification efficiency.

[0079] In another specific embodiment of the present embodiment, the dosing control module determines the target carbon source amount dosed to the back anoxic tank in the following manner:

[0080] The preset internal control concentration value of the effluent TN of the water plant is sequentially subtracted by the current ammonia nitrogen concentration at the end of the back anoxic tank and the organic nitrogen concentration at the end of the back anoxic tank to obtain a basic target value. The current ammonia nitrogen concentration at the end of the back anoxic tank can be measured by an online ammonia nitrogen concentration instrument. The organic nitrogen concentration at the end of the back anoxic tank is an empirical value, which usually has a certain value range in different seasons, different influent loads, and different wastewater treatment plants according to long-term operation data of the wastewater treatment plant.

[0081] The difference between the current second nitrate nitrogen concentration and the basic target value is taken as the target removal amount of nitrate nitrogen in the back anoxic tank.

[0082] The product of the target removal amount and the carbon source equivalent required for removing unit nitrate nitrogen by the carbon source is divided by the concentration of the carbon source agent to obtain a theoretical agent amount. The sum of the compensation amount of the agent required for eliminating dissolved oxygen in the back anoxic tank and the theoretical agent amount is taken as the target carbon source amount.

[0083] That is, the carbon source agent dosing amount of the back anoxic tank = the target removal amount of nitrate nitrogen of the back anoxic tank x the carbon source agent amount required for removing unit nitrate nitrogen + the carbon source agent amount required for eliminating dissolved oxygen in the influent of the back anoxic tank.

[0084] The carbon source equivalent required for removing unit nitrate nitrogen by the carbon source used is an empirical value, which is related to the specific water plant type and the type of carbon source agent used. For example, the pure sodium acetate carbon source equivalent required for removing unit nitrate nitrogen in a daily urban sewage treatment plant is generally between 6 mg and 8 mg. The product of the target removal amount and the carbon source equivalent is the theoretical total amount of carbon source required to eliminate the target removal amount of nitrate nitrogen. In practical applications, the carbon source agent used is usually diluted, so the theoretical total amount of carbon source is divided by the concentration of the carbon source agent used to obtain the theoretical agent amount of the carbon source agent. The concentration of the carbon source agent is generally in mass fraction.

[0085] The agent compensation amount required for eliminating dissolved oxygen (DO) in the post-anoxic tank is also an empirical value, which is related to the specific water plant type and the type of carbon source agent used. For example, the empirical value of the sodium acetate concentration required for eliminating unit dissolved oxygen is 2.56 mg / L,

[0086] The output end of the dosing pipeline is connected to the post-anoxic tank. The above-mentioned dosing control module takes the deviation (basic target value) between the current second nitrate nitrogen concentration and the third nitrate nitrogen concentration at the end of the pre-anoxic tank as the target removal amount, and determines the target carbon source amount based on the carbon source equivalent required for removing unit nitrate nitrogen by the carbon source used, the concentration of the carbon source agent used, and the agent compensation amount required for eliminating dissolved oxygen in the post-anoxic tank. The second nitrate nitrogen concentration, the organic nitrogen concentration at the end of the post-anoxic tank, and the ammonia nitrogen concentration at the end of the post-anoxic tank involved are all control parameters of the post-coupling reaction zone composed of the post-anoxic tank and the post-oxygen tank. Except for the second nitrate nitrogen concentration as the water quality parameter at the inlet of the post-coupling reaction zone, the overall calculation process does not involve the control parameters of the pre-coupling reaction zone, so that the adjustment of the carbon source dosage, as a regulation means, can independently control the denitrification effect of the post-coupling reaction zone, thereby realizing fine control of the post-coupling reaction zone. Moreover, based on the deviation between the current second nitrate nitrogen concentration and the third nitrate nitrogen concentration, the present application can realize precise control of the carbon source dosage, effectively reducing the consumption of carbon source agent.

[0087] The controller provided in the present embodiment can dynamically and accurately adjust the internal reflux ratio of the internal reflux pipeline and the amount of carbon source added to the post-anoxic tank based on the respective independent pipelines according to the changes in the above-mentioned parameters of each reaction tank, thereby improving the denitrification efficiency and reducing the carbon source consumption. The internal reflux control module and the dosing control module work cooperatively, and both independently regulate and control, and cooperatively control the nitrate nitrogen concentration of the sewage flowing through the pre-coupling reaction zone and the post-coupling reaction zone in each adjustment period, thereby ensuring the maximum denitrification efficiency.

[0088] It should be noted that the dosing control module provided in the present application only involves adding carbon source to the post-anoxic tank, but in specific application scenarios, if the influent water quality fluctuates too much, causing the second nitrate nitrogen concentration to be too high and exceeding the maximum treatment capacity of the post-anoxic tank, carbon source can also be added to the pre-anoxic tank to ensure that the effluent TN value is lower than the specified discharge standard.

[0089] In addition, in the third specific embodiment of the present embodiment, in order to cope with the load fluctuation of the post-anoxic tank caused by the sudden increase or decrease of the water plant influent, a dosing dynamic correction module can also be integrated in the controller to ensure that the amount of carbon source added matches the actual demand.

[0090] Specifically, the dosing dynamic correction module is configured to compensate and adjust the target carbon source amount according to the following formula based on the current influent flow of the water plant to determine the final carbon source amount added to the post-anoxic tank in each adjustment period.

[0091]

[0092] wherein C f represents the final carbon source amount added to the post-anoxic tank;

[0093] C g represents the target carbon source amount added to the post-anoxic tank;

[0094] Q0 represents the current influent flow of the water plant;

[0095] Q 设计 represents the design influent flow of the water plant;

[0096] α represents a correction coefficient, and the value range is [0.1, 0.7].

[0097] The correction coefficient is an empirical parameter, which can be dynamically corrected according to the real-time denitrification efficiency (calculated by the nitrate removal rate) to ensure that the amount of carbon source added matches the actual demand. The specific value of α can be obtained by fitting historical data, and preferably, the value range of α is [0.2, 0.5].

[0098] In the above formula, Q0-Q 设计 represents the influent surge / decrease amplitude of the water plant, (Q0-Q 设计 ) / Q 设计 represents the influent surge / decrease rate of the water plant, and the influent surge / decrease rate of the water plant is fused with the above correction coefficient α. When the correction coefficient α is determined, the final carbon source amount added to the post-anoxic tank is dynamically adjusted based on the influent surge / decrease rate of the water plant on the basis of the target carbon source amount, to further improve the precise control of the carbon source dosage and reduce the waste of carbon source reagent.

[0099] Embodiment Three

[0100] Based on the automatic control system for denitrification provided in Embodiment One and Embodiment Two, an automatic control method for denitrification of a five-stage Bardenpho sewage treatment process is provided, which is specifically as follows:

[0101] The embodiment provides an automatic control method for denitrification of a five-stage Bardenpho sewage treatment process, part of sewage at the end of the front aerobic tank is backflowed to the front end of the front anoxic tank through an internal reflux pipeline connected to the end of the front aerobic tank and the front end of the front anoxic tank; the internal reflux ratio of the internal reflux pipeline is controlled according to the first nitrate nitrogen concentration at the end of the front anoxic tank and the second nitrate nitrogen concentration at the front end of the post-anoxic tank; a dosing pipeline connected to the post-anoxic tank at the output end is used to add carbon source to the post-anoxic tank; the dosing amount of the dosing pipeline is controlled according to the second nitrate nitrogen concentration at the front end of the post-anoxic tank, the organic nitrogen concentration at the end of the post-anoxic tank, the ammonia nitrogen concentration at the end of the post-anoxic tank and the preset internal control concentration value of the effluent TN of the water plant.

[0102] Taking a 20,000 tons / day sewage treatment plant using a five-stage Bardenpho process as an example, the specific steps are as follows:

[0103] 1. Equipment configuration

[0104] As shown in Figure 3 , the internal reflux pipeline is provided with an internal reflux pump and an internal reflux flow meter; the dosing pipeline is provided with a carbon source container, a metering pump and a dosing pump; the front end of the front aerobic tank is provided with a water inflow flow meter for measuring the current water inflow Q0 of the water plant; the end of the front anoxic tank is provided with a first nitrate nitrogen concentration meter for collecting the first nitrate nitrogen concentration The front end of the post-anoxic tank is provided with a second nitrate nitrogen concentration meter for collecting the second nitrate nitrogen concentration The end of the post-anoxic tank is provided with an ammonia nitrogen concentration meter for collecting the ammonia nitrogen concentration NH3_N at the end of the post-anoxic tank. 后缺末 The carbon source agent stored in the carbon source container is sodium acetate solution (also known as sodium acetate, CH3COONa), and the concentration of the sodium acetate solution is 25% (mass fraction).

[0105] The controller is in communication connection with the internal reflux pump, the internal reflux flow meter, the metering pump, the dosing pump, the water inflow flow meter, the first nitrate nitrogen concentration meter, the second nitrate nitrogen concentration meter and the ammonia nitrogen concentration meter respectively, so as to collect the corresponding real-time data and control the working frequency of the internal reflux pump and the dosing pump, and further control the internal reflux ratio of the internal reflux pump and the amount of carbon source added.

[0106] 2. Parameter configuration

[0107] The first nitrate nitrogen concentration at the end of the front anoxic tank The control range is set at 1-4 mg / L, based on the design value of the wastewater treatment plant and kept within a reasonably low range.

[0108] Based on the above first nitrate nitrogen concentration The control range can be set to the preset internal control value of the first nitrate nitrogen concentration. Set to the middle value of the control range:

[0109] The internal control value for the third nitrate nitrogen concentration at the end of the post-anoxic tank must simultaneously consider the ammonia nitrogen concentration (NH3-N) and the organic nitrogen concentration (TON) in the post-anoxic tank. 后缺末 To ensure post-hypoxia end-TN ( NH3_N 后缺末 The sum of TON, where lower concentrations of nitrite nitrogen are generally not considered here. (The impact) is that the effluent discharge standard is stably met with a certain safety margin. The current second nitrate nitrogen concentration at the inlet of the post-anoxic tank. Subtracting the internal control value of the third nitrate nitrogen concentration at the end of the post-anoxic tank gives the target nitrate nitrogen removal amount in the post-anoxic tank. If the effluent discharge standard TN is 15 mg / L, to ensure the safety and stability of the effluent quality, the internal control concentration value of TN in the water plant's effluent will be... 出水内控值 Set at 13.5 mg / L, NH3_N 后缺末 =0.2 mg / L (online instrument display value), TON 后缺末 =0.8 mg / L (an empirical value determined through long-term monitoring), then the internal control value for the third nitrate nitrogen concentration at the end of the post-anoxic pool is:

[0110]

[0111] 3. Actual control process

[0112] Within one control cycle, the external reflux ratio r = 70% and the internal reflux ratio R are obtained directly from the instrument or through further calculation based on real-time data. 调整前 =280%, the current first nitrate nitrogen concentration at the end of the pre-anoxic pool. The current second nitrate nitrogen concentration at the front end of the post-anoxic tank The controller's operation steps based on each module include the following steps S1 to S5:

[0113] S1, The first judgment module judges the current first nitrate nitrogen concentration. If the concentration of the first nitrate nitrogen is not within the preset control range of 1-4 mg / L, the system will switch to the internal reflux control module to adjust the internal reflux ratio.

[0114] S2. The internal reflux control module uses the product of the current internal reflux ratio and the second nitrate nitrogen concentration as the current reflux nitrate nitrogen concentration.

[0115]

[0116] The internal reflux control module uses the difference between the current first nitrate nitrogen concentration and the preset internal control value of the first nitrate nitrogen concentration as the target adjustment amount.

[0117]

[0118] The internal reflux control module will adjust the current reflux nitrate nitrogen concentration. The difference between (1+r) times the target adjustment amount As the first proportionality factor; the current second nitrate nitrogen concentration Adjustment amount with target The sum of these factors is used as the second scaling factor; the ratio of the first scaling factor to the second scaling factor is used as the adjusted internal reflux ratio R. 调整后 :

[0119]

[0120] It should be noted that the operating frequency of the internal reflux pump is linearly related to the internal reflux ratio. After determining the adjusted internal reflux ratio, the internal reflux ratio of the internal reflux pipe can be adjusted by increasing or decreasing the operating frequency of the internal reflux pump accordingly.

[0121] S3, The second judgment module judges the current second nitrate nitrogen concentration. The internal control value for the third nitrate nitrogen concentration at the end of the post-anoxic tank is greater than the value for the third nitrate nitrogen concentration. Jump to the dosing control module.

[0122] S4, the dosing control module will set the preset internal control concentration value of TN in the water plant effluent. 出水内控值 Subtract the current ammonia nitrogen concentration (NH3_N) at the end of the anoxic pool in sequence. 后缺末 The organic nitrogen concentration (TON) at the end of the post-anoxic tank is used as the internal control value for the third nitrate nitrogen concentration at the end of the post-anoxic tank. The current second nitrate nitrogen concentration The internal control value of the third nitrate nitrogen concentration The difference is used as the target removal amount of nitrate nitrogen in the post-anoxic tank.

[0123]

[0124] The dosing control module will determine the target removal amount. K is the carbon source equivalent required for removing unit nitrate nitrogen, ω is the concentration of the carbon source agent used, and C is the compensation amount of the agent required for eliminating dissolved oxygen in the post-anoxic tank. 碳源 碳源浓度 , and the compensation amount of the agent required for eliminating dissolved oxygen in the post-anoxic tank C is obtained. DO补偿 g :

[0125]

[0126] In the above formula, the empirical value of K, the carbon source equivalent required for removing unit nitrate nitrogen, is in the range of 6 mg to 10 mg, and in the present embodiment, is specifically taken as 6 mg, that is, the amount of pure sodium acetate required for removing unit nitrate nitrogen is 6 mg, and the amount of sodium acetate with a concentration ω of 25% (mass fraction) is 24 mg. 碳源 碳源浓度 The compensation amount of the agent required for eliminating dissolved oxygen in the post-anoxic tank C is an empirical value, and in the present embodiment, the empirical value determined by the sewage treatment plant according to historical operation data is 2 mg / L. DO补偿

[0127] S5, the dynamic correction module of the agent addition, based on the current inflow Q0 of the water plant, adjusts the target carbon source amount C according to the following formula, takes α = 0.3, and determines the final carbon source amount C added to the post-anoxic tank: g f :

[0128]

[0129] wherein (Q0-Q 设计 ) / Q 设计 is determined according to the current inflow Q0 of the water plant and the design inflow Q 设计 of the water plant, and represents the sudden increase rate or sudden decrease rate of the current inflow.

[0130] Based on the above final carbon source amount, the working frequency of the agent addition pump is controlled, that is, the carbon source amount added to the post-anoxic tank is correspondingly controlled.

[0131] Compared with the target carbon source amount 62 mg / L calculated by the agent addition control module, the final carbon source amount determined by the dynamic correction module of the agent addition according to the current inflow is 58 mg / L, which reduces the carbon source consumption by 6%.

[0132] ​​​​​The denitrification automatic control method provided by the embodiment can automatically control the change of the parameters of each reaction tank, dynamically and accurately adjust the internal reflux ratio of the internal reflux pipeline and the amount of carbon source added to the backward anoxic tank based on the respective independent pipelines, improve the denitrification efficiency, and reduce the carbon source consumption. Meanwhile, both are independently controlled, and the nitrate nitrogen concentration of the sewage flowing through the front and rear coupling reaction zones in each adjustment period is cooperatively controlled to maximize the denitrification efficiency. Moreover, the fully automated control method reduces the degree of manual intervention and greatly reduces the operating cost.

[0133] Since the system / device for implementing the method of the embodiments of the present application is described in the above embodiments of the present application, the specific structure and modifications of the system / device can be understood by those skilled in the art based on the method described in the above embodiments of the present application, and thus will not be described here. Any system / device used in the method of the above embodiments of the present application belongs to the scope of protection of the present application.

[0134] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0135] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system) and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions.

[0136] It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the claims, the word "comprising" does not exclude the presence of other elements or steps than those listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. It is understood that the word should be interpreted as the article "a" or "an" preceding the first element of the list of elements, that, however, does not exclude the presence of a plurality of such elements. The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the claims, the word "first", "second", "third", etc. does not have any order of magnitude, but is used to distinguish between different elements. The word "first", "second", "third", etc. can be understood as part of the name of the element.

[0137] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0138] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims should be interpreted to include the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0139] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations fall within the scope of the claims of this application and their equivalents, then this application should also include these modifications and variations.

Claims

1. A nitrogen removal automatic control system for a five-stage Bardenpho sewage treatment process, the five-stage Bardenpho sewage treatment process being implemented based on a plurality of reaction tanks, the reaction tanks including an anaerobic tank, a front anoxic tank, a front aerobic tank, a rear anoxic tank, and a rear aerobic tank connected in sequence, characterized in that, The automatic control system comprises a controller which controls the nitrogen removal efficiency of the five-stage Bardenpho sewage treatment process through a regulating component arranged on the multiple reaction tanks; The regulating component comprises: an internal reflux pipeline connected to the end of the front aerobic tank and the front end of the front anoxic tank, for refluxing part of the sewage at the end of the front aerobic tank to the front end of the front anoxic tank; a dosing pipeline with an output end connected to the rear anoxic tank, for adding carbon source to the rear anoxic tank; The controller is in communication connection with the internal reflux pipeline and the dosing pipeline, respectively, for controlling the internal reflux ratio of the internal reflux pipeline according to the first nitrate nitrogen concentration at the end of the front anoxic tank and the second nitrate nitrogen concentration at the front end of the rear anoxic tank, and controlling the amount of carbon source added to the rear anoxic tank according to the second nitrate nitrogen concentration at the front end of the rear anoxic tank, the organic nitrogen concentration at the end of the rear anoxic tank, the ammonia nitrogen concentration at the end of the rear anoxic tank and the preset internal control concentration value of the effluent TN of the water plant; The controller comprises a second judgment module and a dosing control module; The second judgment module is configured to judge whether the current second nitrate nitrogen concentration is greater than the internal control value of the third nitrate nitrogen concentration at the end of the rear anoxic tank in each adjustment period, and if yes, jump to the dosing control module; The dosing control module is configured to determine the target removal amount of nitrate nitrogen in the rear anoxic tank according to the second nitrate nitrogen concentration, the organic nitrogen concentration at the end of the rear anoxic tank, the ammonia nitrogen concentration at the end of the rear anoxic tank and the preset internal control concentration value of the effluent TN of the water plant, and determine the target carbon source amount added to the rear anoxic tank according to the target removal amount; The controller further comprises: a dosing dynamic correction module configured to compensate and adjust the target carbon source amount according to the following formula based on the current inflow of the water plant in each adjustment period to determine the final carbon source amount added to the rear anoxic tank; ； wherein, represents the amount of final carbon source added in the post-anoxic tank; represents the target amount of carbon source to be added to the backward anoxic tank; represents the current inflow flow rate of the water plant; Qd represents the design inflow of the water plant; denotes a correction factor, which takes values in the range [0.1, 0.7].

2. The automatic denitration control system according to claim 1, wherein The controller comprises a first judgment module and an internal reflux control module; The first judgment module is configured to judge whether the current first nitrate nitrogen concentration is within the preset control interval in each adjustment period, and if not, jump to the internal reflux control module; The internal reflux control module is configured to calculate the reflux nitrate nitrogen concentration of the reflux sewage of the internal reflux pipeline, calculate the target adjustment amount of the first nitrate nitrogen concentration, and determine the adjusted internal reflux ratio according to the reflux nitrate nitrogen concentration and the target adjustment amount.

3. The automatic denitration control system according to claim 2, wherein In the internal reflux control module, calculating the current reflux nitrate nitrogen concentration of the reflux sewage of the internal reflux pipeline and calculating the target adjustment amount of the first nitrate nitrogen concentration comprises: multiplying the current internal reflux ratio and the second nitrate nitrogen concentration to obtain the current reflux nitrate nitrogen concentration; calculating the difference between the current first nitrate nitrogen concentration and the preset internal control value of the first nitrate nitrogen concentration as the target adjustment amount.

4. The automatic denitration control system according to claim 2, wherein In the internal reflux control module, determining the adjusted internal reflux ratio according to the reflux nitrate nitrogen concentration and the target adjustment amount comprises: calculating the difference between the current reflux nitrate nitrogen concentration and the target adjustment amount multiplied by (1+r) as the first proportion factor, wherein r is the external reflux ratio of the five-stage Bardenpho sewage treatment process. a sum of the current second nitrate nitrogen concentration and the target adjustment amount, as a second proportional factor; a ratio of the first proportional factor to the second proportional factor, as an adjusted internal reflux ratio.

5. The automatic denitration control system according to claim 1, wherein In the dosing control module, according to the second nitrate nitrogen concentration, the organic nitrogen concentration at the end of the post-anoxic tank, the ammonia nitrogen concentration at the end of the post-anoxic tank, and the preset internal control concentration value of the water plant effluent TN, a target removal amount of nitrate nitrogen in the post-anoxic tank is determined, including: subtracting the preset internal control concentration value of the water plant effluent TN from the current ammonia nitrogen concentration at the end of the post-anoxic tank and the organic nitrogen concentration at the end of the post-anoxic tank in turn, as a basic target value; differencing the current second nitrate nitrogen concentration from the basic target value, as the target removal amount of nitrate nitrogen in the post-anoxic tank.

6. The automatic denitration control system according to claim 1, wherein In the dosing control module, according to the target removal amount, a target carbon source amount to be added to the post-anoxic tank is determined, including: multiplying the target removal amount by the carbon source equivalent required by the used carbon source to remove unit nitrate nitrogen, and dividing by the concentration of the used carbon source agent, to obtain a theoretical agent amount, and adding an agent compensation amount required to eliminate dissolved oxygen in the post-anoxic tank to the theoretical agent amount, as the target carbon source amount.

7. The automatic denitration control system according to claim 1, wherein The control assembly further includes: an internal reflux pump and an internal reflux flow meter arranged on the internal reflux pipeline; and / or, a carbon source container, a metering pump, and a dosing pump arranged on the dosing pipeline; and / or, a water inlet flow meter arranged at the front end of the pre-oxic tank; and / or, a first nitrate nitrogen concentration meter arranged at the end of the pre-anoxic tank; and / or, a second nitrate nitrogen concentration meter arranged at the front end of the post-anoxic tank; and / or, an ammonia nitrogen concentration meter arranged at the end of the post-anoxic tank.

8. A method for automatic control of nitrogen removal in a five-stage Bardenpho sewage treatment process, characterized by, The denitrification automatic control method is based on the denitrification automatic control system of the five-stage Bardenpho sewage treatment process according to any one of claims 1 to 7, to control the denitrification efficiency of the five-stage Bardenpho sewage treatment process.

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