Aeration control method for sewage treatment plant

Abstract

The present invention relates to a sewage treatment plant aeration control method, comprising the following steps: setting a desired dissolved oxygen value in a control system and setting performance parameters of a blower in the control system; detecting the sludge oxygen consumption rate and dissolved oxygen concentration in the sewage treatment tank, calculating the oxygen supply by the control system based on the detected sludge oxygen consumption rate and dissolved oxygen concentration, calculating the aeration volume required for the set dissolved oxygen value based on actual aeration parameters and oxygen transfer rate, calculating the required aeration volume according to a model, and automatically adjusting the blower according to the aeration volume Q and the adjustment period T to control the aeration rate in the aeration tank. The present invention improves the control accuracy and efficiency of aeration regulation in the sewage treatment plant aeration tank by optimizing aeration control logic, utilizing the actual dissolved oxygen concentration value detected online to quickly determine the adjustment measures within the adjustment period, and fully considering the influence of sewage temperature on oxygen dissolution.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to an aeration control method for a sewage treatment plant. Background Art

[0002] In biological wastewater treatment, aeration is the most energy-intensive process. Reducing energy consumption during the aeration phase is crucial for wastewater treatment plants to achieve energy conservation and consumption reduction. Aeration control strategies utilize automated control instruments and equipment to automatically and precisely regulate the aeration volume during the wastewater treatment process, achieving stable effluent quality, reducing energy consumption, and minimizing human intervention.

[0003] The most common aeration control method in China is still the relatively extensive manual debugging method, which usually determines the aeration volume based on the operator's experience. If there is no long-term and obvious fluctuation in the effluent water quality, the aeration volume will not be adjusted in real time. Once the operating conditions change, the aeration volume is still adjusted up or down based on experience, resulting in problems such as insufficient or excessive aeration. Some treatment plants even have their aeration systems operating at overload for a long time, which not only fails to guarantee the effluent water quality, but also causes a large amount of energy waste.

[0004] The DO (dissolved oxygen) control method uses PID feedback to monitor the DO concentration and adjust the air volume to a preset value when external conditions change regularly. However, there is a significant lag between changes in air volume, influent quality and quantity, and the reflected changes in dissolved oxygen. This makes this control method always "slow," and adjustments often lead to misjudgments, significantly reducing its practicality. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides an aeration control method for a sewage treatment plant to solve the technical difficulties existing in the prior art.

[0006] The technical objectives of the present invention are achieved through the following technical solutions:

[0007] A method for controlling aeration in a sewage treatment plant comprises the following steps:

[0008] Set the expected dissolved oxygen value in the control system and set the performance parameters of the blower in the control system;

[0009] Detect the sludge oxygen consumption rate and dissolved oxygen concentration in the sewage treatment tank. Based on the detected sludge oxygen consumption rate and dissolved oxygen concentration, the control system calculates the oxygen supply. Based on the actual aeration parameters and oxygen transfer rate, the control system calculates the aeration volume required for the dissolved oxygen set value.

[0010] The calculation formula for the aeration rate required to increase the actual dissolved oxygen concentration to the set value is:

[0011] ;

[0012] Where Q is the aeration rate, OUR is the activated sludge oxygen consumption rate, is the volume of sludge in the aeration tank, SOTE is the oxygen utilization rate of the aerator under standard conditions, V 曝气池 is the volume of the aeration tank, t is the water temperature in the aeration tank (℃); P 预期值 is the expected dissolved oxygen concentration, P 实际值 is the actual dissolved oxygen concentration;

[0013] The control system automatically adjusts the blower according to the aeration volume Q and the adjustment period T to control the aeration rate in the aeration tank.

[0014] Preferably, the activated sludge oxygen consumption rate OUR is measured online by an oxygen consumption rate meter, and the time interval of the online measurement is 10 minutes.

[0015] Preferably, the actual dissolved oxygen concentration is obtained by real-time monitoring by a dissolved oxygen monitor.

[0016] Preferably, when the actual dissolved oxygen concentration value is lower than the expected dissolved oxygen concentration value, the adjustment period T is set to 20 minutes while the sludge oxygen consumption rate remains unchanged, and the aeration rate within the adjustment period T is calculated by the calculated aeration volume Q, thereby increasing the blowing rate of the blower;

[0017] When the actual dissolved oxygen concentration is greater than the expected dissolved oxygen concentration, the adjustment period T is set to 10 minutes while the sludge oxygen consumption rate remains unchanged. The aeration rate within the adjustment period T is calculated using the calculated aeration volume Q, and the blower rate is then reduced.

[0018] The actual dissolved oxygen concentration value is tested every 10 minutes. When the actual dissolved oxygen concentration value is equal to the expected dissolved oxygen concentration value, the expected regulation target is achieved.

[0019] Compared with the existing methods, the present invention has the following beneficial effects:

[0020] The present invention optimizes aeration control logic, utilizes the actual dissolved oxygen concentration value detected online to quickly determine the adjustment measures within the adjustment cycle, and fully considers the influence of sewage temperature on oxygen dissolution, thereby improving the control accuracy and efficiency of aeration regulation in the aeration tank of a sewage treatment plant.

[0021] The present invention can significantly reduce the energy consumption of the aeration system in a sewage treatment plant by optimizing the aeration control logic. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to specific embodiments.

[0023] This embodiment provides a method for controlling aeration in a sewage treatment plant, comprising the following steps:

[0024] Set the expected dissolved oxygen value in the control system and set the performance parameters of the blower in the control system;

[0025] Detect the sludge oxygen consumption rate and dissolved oxygen concentration in the sewage treatment tank. Based on the detected sludge oxygen consumption rate and dissolved oxygen concentration, the control system calculates the oxygen supply. Based on the actual aeration parameters and oxygen transfer rate, the control system calculates the aeration volume required for the dissolved oxygen set value.

[0026] The calculation formula for the aeration rate required to increase the actual dissolved oxygen concentration to the set value is:

[0027] ;

[0028] Where Q is the aeration rate, OUR is the activated sludge oxygen consumption rate, is the volume of sludge in the aeration tank, SOTE is the oxygen utilization rate of the aerator under standard conditions, V 曝气池 is the volume of the aeration tank, t is the water temperature in the aeration tank (℃); P 预期值 is the expected dissolved oxygen concentration, P 实际值 is the actual dissolved oxygen concentration;

[0029] The control system automatically adjusts the blower according to the aeration volume Q and the adjustment period T to control the aeration rate in the aeration tank.

[0030] In the above embodiment, the activated sludge oxygen consumption rate OUR is measured online by an oxygen consumption rate meter, and the time interval of the online measurement is 10 minutes.

[0031] It should be noted that the actual dissolved oxygen concentration is obtained by real-time monitoring using a dissolved oxygen monitor. Existing sewage treatment plants are equipped with oxygen consumption rate meters and dissolved oxygen monitors in their aeration tanks. When implementing the present invention, the oxygen consumption rate meters and dissolved oxygen monitors can be connected to the control system, and the blower can be connected to the control system. This system modification presents minimal technical barriers and is relatively low cost.

[0032] In some preferred embodiments, when the actual dissolved oxygen concentration is less than the expected dissolved oxygen concentration, the adjustment period T is set to 20 minutes while the sludge oxygen consumption rate remains unchanged, and the aeration rate within the adjustment period T is calculated using the calculated aeration volume Q, thereby increasing the blower rate.

[0033] When the actual dissolved oxygen concentration is greater than the expected dissolved oxygen concentration, the adjustment period T is set to 10 minutes while the sludge oxygen consumption rate remains unchanged. The aeration rate within the adjustment period T is calculated using the calculated aeration volume Q, and the blower rate is then reduced.

[0034] The actual dissolved oxygen concentration value is tested every 10 minutes. When the actual dissolved oxygen concentration value is equal to the expected dissolved oxygen concentration value, the expected regulation target is achieved.

[0035] It should be noted that in order to improve the regulation efficiency of the aeration system, the detection cycle can be changed according to the water quality of the sewage treatment plant. When the water quality of the sewage treatment plant is relatively stable, the detection of the actual dissolved oxygen concentration value can be appropriately extended, for example, it can be extended to 20 minutes or 30 minutes. When the water quality of the sewage treatment plant is unstable, the detection cycle can be appropriately shortened, for example, it can be shortened to 8 minutes or 5 minutes, so as to further improve the aeration control efficiency and achieve the purpose of precise technology and energy saving.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for controlling aeration in a sewage treatment plant, characterized in that: The following steps are involved: Set the expected dissolved oxygen value in the control system and set the performance parameters of the blower in the control system; Detect the sludge oxygen consumption rate and dissolved oxygen concentration in the sewage treatment tank. Based on the detected sludge oxygen consumption rate and dissolved oxygen concentration, the control system calculates the oxygen supply. Based on the actual aeration parameters and oxygen transfer rate, the control system calculates the aeration volume required for the dissolved oxygen set value. The calculation formula for the aeration rate required to increase the actual dissolved oxygen concentration to the set value is: ； Where Q is the aeration rate, OUR is the activated sludge oxygen consumption rate, is the volume of sludge in the aeration tank, SOTE is the oxygen utilization rate of the aerator under standard conditions, V 曝气池 is the volume of the aeration tank, t (℃) is the water temperature in the aeration tank; P 预期值 is the expected dissolved oxygen concentration, P 实际值 is the actual dissolved oxygen concentration; The control system automatically adjusts the blower according to the aeration volume Q and the adjustment period T to control the aeration rate in the aeration tank.

2. A sewage treatment plant aeration control method according to claim 1, characterized in that: The activated sludge oxygen consumption rate OUR is measured online by an oxygen consumption rate meter, and the time interval of the online measurement is 10 minutes.

3. A sewage treatment plant aeration control method according to claim 1, characterized in that: The actual dissolved oxygen concentration is obtained by real-time monitoring by a dissolved oxygen monitor.

4. A sewage treatment plant aeration control method according to claim 1, characterized in that: When the actual dissolved oxygen concentration is lower than the expected dissolved oxygen concentration, the adjustment period T is set to 20 minutes while the sludge oxygen consumption rate remains unchanged. The aeration rate within the adjustment period T is calculated using the calculated aeration volume Q, thereby increasing the blower rate. When the actual dissolved oxygen concentration is greater than the expected dissolved oxygen concentration, the adjustment period T is set to 10 minutes while the sludge oxygen consumption rate remains unchanged. The aeration rate within the adjustment period T is calculated using the calculated aeration volume Q, and the blower rate is then reduced. The actual dissolved oxygen concentration value is tested every 10 minutes. When the actual dissolved oxygen concentration value is equal to the expected dissolved oxygen concentration value, the expected regulation target is achieved.

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