A control system and method for carbon source addition of domestic sewage

Abstract

This invention discloses a control system and method for adding carbon sources to domestic sewage, applied in the field of sewage treatment technology. It includes a sewage treatment unit, a carbon source addition unit, and an intelligent control unit. The sewage treatment unit comprises an anaerobic tank, an anoxic tank, an aerobic tank, and a secondary sedimentation tank connected in sequence. An internal return pipe is provided between the effluent end of the anoxic tank and the influent end of the aerobic tank; an external return pipe is provided between the effluent end of the secondary sedimentation tank and the influent end of the anaerobic tank. The intelligent control unit calculates the theoretical dosage based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, according to the influent load. It then dynamically adjusts the theoretical dosage based on the corresponding fluid flow rates in the internal and external return pipes and the nitrate nitrogen concentration in the effluent of the anoxic tank, according to the nitrate nitrogen concentration deviation, thereby controlling the carbon source addition unit to add carbon sources. This invention achieves precise and dynamic carbon source addition, improving denitrification efficiency and reducing operating costs.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically to a control system and method for adding carbon sources to domestic sewage. Background Technology

[0002] During coal mining operations, a large amount of domestic wastewater enters sewage ponds. This wastewater typically originates from sewage discharged from staff canteens, bathrooms, dormitories, and offices within the coal mine's living area. Coal mine sewage contains significant amounts of organic matter and pollutants such as nitrogen and phosphorus, which not only lead to eutrophication and algal blooms, but also pose a serious threat to aquatic life and human health.

[0003] The carbon-to-nitrogen ratio (C / N) in coal mine domestic wastewater is generally low, resulting in insufficient carbon source during biological denitrification in coal mines and affecting denitrification efficiency. Traditional carbon source addition methods often employ constant dosage or manual adjustment, which suffer from problems such as response lag, inaccurate addition, waste, or effluent exceeding standards. Although existing technologies employ feedforward or feedback control carbon source addition systems, they often suffer from problems such as a single control model, poor adaptability, and difficulty in coping with water quality fluctuations.

[0004] Therefore, how to provide a control system and method for adding carbon sources to domestic sewage that can achieve precise and dynamic carbon source addition, improve denitrification efficiency and reduce operating costs is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a control system and method for adding carbon sources to domestic sewage. The aim is to achieve precise and dynamic addition of carbon sources through a feedforward-feedback composite control strategy, thereby improving denitrification efficiency and reducing operating costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A control system for adding carbon source to domestic sewage includes: a sewage treatment unit, a carbon source addition unit, and an intelligent control unit; The wastewater treatment unit includes: an anaerobic tank, an anoxic tank, an aerobic tank, and a secondary sedimentation tank connected in sequence; wherein, an internal return pipe is provided between the effluent end of the anoxic tank and the effluent end of the aerobic tank; and an external return pipe is provided between the effluent end of the secondary sedimentation tank and the effluent end of the anaerobic tank. The intelligent control unit is used to calculate the theoretical dosage based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank and the influent load. It also combines the corresponding fluid flow rates in the internal and external return pipes and the nitrate nitrogen concentration in the effluent of the anoxic tank to dynamically correct the theoretical dosage according to the nitrate nitrogen concentration deviation, thereby controlling the carbon source dosing unit to add carbon source.

[0007] Optional, the carbon source dosing unit includes: a carbon source storage tank, a diaphragm metering pump, an electric valve, and a dosing flow meter; The intelligent control unit controls the frequency and flow rate of the diaphragm metering pump to add carbon source; the carbon source addition point is set at the inlet end of the anoxic tank.

[0008] Optionally, the intelligent control unit includes: an information acquisition module, a feedforward control module, a feedback control module, and an execution control module; The information acquisition module includes: influent flow meter, COD online analyzer, ammonia nitrogen online analyzer, internal reflux flow meter and external reflux flow meter, and effluent nitrate nitrogen online analyzer; The feedforward control module is used to calculate the theoretical dosage. The feedback control module is used to dynamically correct the theoretical dosage. The execution control module is used to control the carbon source dosing unit to do carbon source dosing.

[0009] Optionally, based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, the theoretical dosage is calculated according to the influent load, specifically:

[0010] in, This is the theoretical dosage. The COD concentration of the influent to the anaerobic tank; This refers to the influent flow rate of the anaerobic tank. , , It is a constant; The safety factor is calculated based on influent ammonia nitrogen concentration data and adjusted according to empirical principles. is the feedforward coefficient.

[0011] Optionally, based on the corresponding fluid flow rates in the internal and external return pipes and the nitrate and nitrogen concentrations in the effluent from the anoxic tank, the theoretical dosage is dynamically adjusted according to the nitrate and nitrogen concentration deviation, specifically as follows:

[0012] in, This is the revised theoretical dosage; This refers to the nitrate and nitrogen concentration in the effluent from the anoxic tank. The target value for nitrate and nitrogen concentration in the effluent of the anoxic tank; This refers to the influent flow rate of the anaerobic tank. The fluid flow rate in the internal return pipe is the wastewater containing nitrate nitrogen; The fluid flow rate in the external return pipe is the activated sludge mixed liquor. It is a constant; This is the feedback coefficient.

[0013] Optionally, the intelligent control unit uses a PLC as the core controller, supporting PID regulation and remote monitoring.

[0014] This invention also provides a control method for adding carbon sources to domestic sewage using a control system for adding carbon sources to domestic sewage, comprising: Step 1: Real-time data collection of influent flow rate, COD concentration, ammonia nitrogen concentration in the anaerobic tank, fluid flow rate in the internal and external return pipes, and nitrate nitrogen concentration in the effluent of the anoxic tank. Step 2: Based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, calculate the theoretical dosage according to the influent load. Combined with the corresponding fluid flow rates in the internal and external return pipes and the nitrate nitrogen concentration in the effluent of the anoxic tank, dynamically adjust the theoretical dosage according to the nitrate nitrogen concentration deviation, thereby controlling the carbon source addition unit to add carbon source.

[0015] As can be seen from the above technical solution, compared with the prior art, this invention discloses a control system and method for adding carbon sources to domestic sewage. By monitoring influent water quality parameters in real time and dynamically adjusting the carbon source dosage, the carbon source demand in the biological denitrification process is met, significantly improving denitrification efficiency. The combination of feedforward control and feedback control avoids insufficient or excessive carbon source dosage, reduces carbon source waste, lowers operating costs, improves the system's anti-interference ability, ensures stable effluent water quality compliance, realizes automated and intelligent management of carbon source addition, reduces manual intervention, and improves management efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the system structure provided by the present invention.

[0018] Figure 2 This is a schematic diagram of the method flow provided by the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: Embodiment 1 of the present invention discloses a control system for adding carbon sources to domestic sewage, such as... Figure 1 As shown, it includes: a wastewater treatment unit, a carbon source dosing unit, and an intelligent control unit.

[0021] The wastewater treatment unit includes: an anaerobic tank, an anoxic tank, an aerobic tank, and a secondary sedimentation tank connected in sequence; wherein, an internal return pipe is provided between the effluent end of the anoxic tank and the effluent end of the aerobic tank; and an external return pipe is provided between the effluent end of the secondary sedimentation tank and the effluent end of the anaerobic tank.

[0022] The intelligent control unit is used to calculate the theoretical dosage based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank and the influent load. It also combines the corresponding fluid flow rates in the internal and external return pipes and the nitrate nitrogen concentration in the effluent of the anoxic tank to dynamically correct the theoretical dosage according to the nitrate nitrogen concentration deviation, thereby controlling the carbon source dosing unit to add carbon source.

[0023] Based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, the theoretical dosage is calculated according to the influent load, as follows:

[0024] in, This is the theoretical dosage. The COD concentration of the influent to the anaerobic tank; This refers to the influent flow rate of the anaerobic tank. , , It is a constant; The safety factor is calculated based on influent ammonia nitrogen concentration data and adjusted according to empirical principles. is the feedforward coefficient.

[0025] Wastewater denitrification typically involves two steps: 1. Nitrification: Ammonia nitrogen is oxidized to nitrate under aerobic conditions. 2. Denitrification: Nitrate is reduced to nitrogen gas under anaerobic conditions. Denitrifying bacteria require an external carbon source to provide biological energy to complete the denitrification process. A lack of carbon source will prevent effective nitrate removal, leading to excessive total nitrogen in the effluent. The purpose of setting up an influent ammonia nitrogen meter to measure the influent ammonia nitrogen concentration is to determine the focus of water treatment monitoring. If the influent ammonia nitrogen concentration remains consistently high, and the effluent ammonia nitrogen concentration is also high, it indicates that the problem lies in increasing aeration rather than the amount of carbon source. Furthermore, long-term collection of influent ammonia nitrogen concentration data allows for the adjustment of the safety factor in the feedforward formula based on empirical principles. . The value ranges from 1.05 to 1.20, and the fluctuation of ammonia nitrogen is the determining factor. The important basis for determining the value.

[0026] Based on the corresponding fluid flow rates in the internal and external return pipes and the nitrate and nitrogen concentrations in the effluent from the anoxic tank, the theoretical dosage is dynamically adjusted according to the nitrate and nitrogen concentration deviation, specifically as follows:

[0027] in, This is the revised theoretical dosage; This refers to the nitrate and nitrogen concentration in the effluent from the anoxic tank. The target value for nitrate and nitrogen concentration in the effluent of the anoxic tank; This refers to the influent flow rate of the anaerobic tank. The fluid flow rate in the internal return pipe is the wastewater containing nitrate nitrogen; The fluid flow rate in the external return pipe is the activated sludge mixed liquor. It is a constant; This is the feedback coefficient.

[0028] The carbon source dosing unit includes: a carbon source storage tank, a diaphragm metering pump, an electric valve, and a dosing flow meter; The intelligent control unit controls the frequency and flow rate of the diaphragm metering pump to add carbon source; the carbon source addition point is set at the inlet end of the anoxic tank.

[0029] The intelligent control unit includes: an information acquisition module, a feedforward control module, a feedback control module, and an execution control module; The information acquisition module includes: influent flow meter, COD online analyzer, ammonia nitrogen online analyzer, internal reflux flow meter and external reflux flow meter, and effluent nitrate nitrogen online analyzer; The feedforward control module is used to calculate the theoretical dosage. The feedback control module is used to dynamically correct the theoretical dosage. The execution control module is used to control the carbon source dosing unit to do carbon source dosing.

[0030] The intelligent control unit uses Siemens PLC-1200 as the core controller, which supports PID regulation and remote monitoring. Specifically, parameter settings, status monitoring and alarm management are performed through the HMI interface or a remote platform.

[0031] Example 2: Embodiment 2 of the present invention discloses a control method for adding carbon sources to domestic sewage using a control system for adding carbon sources to domestic sewage, such as... Figure 2 As shown, it includes: Step 1: Real-time data collection of influent flow rate, COD concentration, ammonia nitrogen concentration in the anaerobic tank, fluid flow rate in the internal and external return pipes, and nitrate nitrogen concentration in the effluent of the anoxic tank. Step 2: Based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, calculate the theoretical dosage according to the influent load. Combined with the corresponding fluid flow rates in the internal and external return pipes and the nitrate nitrogen concentration in the effluent of the anoxic tank, dynamically adjust the theoretical dosage according to the nitrate nitrogen concentration deviation, thereby controlling the carbon source addition unit to add carbon source.

[0032] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0033] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control system for adding carbon source to domestic sewage, characterized in that, include: Wastewater treatment unit, carbon source dosing unit, and intelligent control unit; The wastewater treatment unit includes: an anaerobic tank, an anoxic tank, an aerobic tank, and a secondary sedimentation tank connected in sequence; wherein, an internal return pipe is provided between the effluent end of the anoxic tank and the effluent end of the aerobic tank; and an external return pipe is provided between the effluent end of the secondary sedimentation tank and the effluent end of the anaerobic tank. The intelligent control unit is used to calculate the theoretical dosage based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, according to the influent load, and dynamically correct the theoretical dosage based on the nitrate nitrogen concentration deviation of the effluent in the internal and external return pipes, thereby controlling the carbon source dosing unit to do carbon source.

2. The control system for adding carbon source to domestic sewage according to claim 1, characterized in that, The carbon source dosing unit includes: a carbon source storage tank, a diaphragm metering pump, an electric valve, and a dosing flow meter; The intelligent control unit controls the frequency and flow rate of the diaphragm metering pump to add the carbon source; wherein the carbon source is added at the inlet of the anoxic tank.

3. The control system for adding carbon source to domestic sewage according to claim 1, characterized in that, The intelligent control unit includes: an information acquisition module, a feedforward control module, a feedback control module, and an execution control module; The information acquisition module includes: an influent flow meter, an online COD analyzer, an online ammonia nitrogen analyzer, an internal reflux flow meter, an external reflux flow meter, and an online effluent nitrate nitrogen analyzer; The feedforward control module is used to calculate the theoretical dosage. The feedback control module is used to dynamically correct the theoretical dosage. The execution control module is used to control the carbon source dosing unit to do carbon source dosing.

4. The control system for adding carbon source to domestic sewage according to claim 1, characterized in that, Based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, the theoretical dosage is calculated according to the influent load, specifically as follows: in, This is the theoretical dosage. The COD concentration of the influent to the anaerobic tank; The influent flow rate of the anaerobic tank; , , It is a constant; The safety factor is calculated based on influent ammonia nitrogen concentration data and adjusted according to empirical principles. is the feedforward coefficient.

5. The control system for adding carbon source to domestic sewage according to claim 1, characterized in that, Based on the corresponding fluid flow rates in the internal and external return pipes and the nitrate and nitrogen concentrations in the effluent from the anoxic tank, the theoretical dosage is dynamically adjusted according to the nitrate and nitrogen concentration deviation, specifically as follows: in, This is the revised theoretical dosage; The nitrate concentration in the effluent from the anoxic tank; The target value for nitrate nitrogen concentration in the effluent of the anoxic tank; The influent flow rate of the anaerobic tank; The fluid flow rate in the internal return pipe is the wastewater containing nitrate nitrogen; The fluid flow rate in the external return pipe is the activated sludge mixed liquor. It is a constant; This is the feedback coefficient.

6. The control system for adding carbon source to domestic sewage according to claim 1, characterized in that, The intelligent control unit uses a PLC as the core controller and supports PID regulation and remote monitoring.

7. A method for controlling the addition of a carbon source to domestic sewage using a control system for adding a carbon source to domestic sewage according to any one of claims 1-6, characterized in that, include: Step 1: Real-time data collection of influent flow rate, COD concentration, ammonia nitrogen concentration in the anaerobic tank, fluid flow rate in the internal and external return pipes, and nitrate nitrogen concentration in the effluent of the anoxic tank. Step 2: Based on the influent flow rate, COD, and ammonia nitrogen concentration of the anaerobic tank, calculate the theoretical dosage according to the influent load. Combined with the corresponding fluid flow rates in the internal and external return pipes and the nitrate nitrogen concentration in the effluent of the anoxic tank, dynamically adjust the theoretical dosage according to the nitrate nitrogen concentration deviation, thereby controlling the carbon source addition unit to add carbon source.

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