Low-energy-consumption MBBR process system stable operation regulation and control method

Abstract

The invention discloses a low-energy-consumption MBBR process system stable operation regulation and control method, and belongs to the technical field of water treatment. The device comprises a first reaction tank, a second reaction tank, a third reaction tank and auxiliary accessories which are sequentially arranged from front to back, the auxiliary accessories comprise flashboards, valves and water inlet pipes, each reaction tank is internally provided with an aeration pipe with adjustable air volume, different operation modes can be realized through the arranged valves, and in the corresponding operation mode, the aeration pipes are communicated with the valves. And different water inlet loads can be coped with by adjusting the aeration rate. According to the MBBR process, flexible regulation and control are achieved according to the actual inflow water quality and quantity, it is guaranteed that the effluent water quality stably reaches the standard, invalid air volume waste is reduced, and energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a method for stable operation control of a low-energy MBBR process system. Background Technology

[0002] The Moving Bed Biofilm Reactor (MBBR) is a highly efficient process system for wastewater treatment. Its microbiological essence is the biofilm method, achieving efficient and specific enrichment of functional bacteria, with a relative abundance more than 10 times higher than that of activated sludge processes, resulting in a significant improvement in macroscopic treatment efficiency. During process operation, the fluidization of the suspended carrier is crucial. Fluidization is a prerequisite for optimal process performance and a foundation for safe and reliable operation. If the suspended carrier does not fluidize, it can lead to carrier accumulation or blockage, affecting process safety. Therefore, sufficient fluidization power is required. However, in actual operation, the quality and quantity of the wastewater to be treated are constantly changing. When the quality and quantity of the wastewater are lower than the design values, from the perspective of pollutant removal, the aeration airflow can be reduced. However, from the application perspective, reducing the airflow may lead to the risk of the suspended carrier not fluidizing, thus necessitating the provision of an airflow exceeding actual needs, resulting in increased energy consumption.

[0003] Existing technologies for reducing system energy consumption include methods such as reducing aeration volume and online monitoring. However, these methods carry the risk of suspended carrier non-fluidization and are not suitable for various operating modes. Furthermore, the aeration volume cannot be precisely adjusted when the operating mode changes. Other methods involve multi-mode control based on influent water quality, primarily aimed at meeting standards rather than reducing energy consumption. Therefore, this invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for stable operation and control of a low-energy MBBR process system. A multi-mode operation method for MBBR is set up to address changes in water quality and quantity, and an aeration control method matching this multi-mode operation method is studied. By combining the two, low-energy operation of the MBBR process system can be achieved.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for stable operation control of a low-energy MBBR process system includes the following steps:

[0007] a. The MBBR process system includes a first reaction tank, a second reaction tank, a third reaction tank, and auxiliary accessories arranged from front to back. The auxiliary accessories include gate valves, valves, and inlet pipes. Each reaction tank is equipped with an aeration pipe with an adjustable air volume design. Suspended carriers are added to all three reaction tanks.

[0008] b. The MBBR system has three operating modes: Mode A, Mode B, and Mode C. The specific route of Mode A is: wastewater flows out after passing through the first reaction tank, the second reaction tank, and the third reaction tank; the specific route of Mode B is: wastewater flows out after passing through the second reaction tank and the third reaction tank; and the specific route of Mode C is: wastewater flows out after passing through the third reaction tank.

[0009] c. When the influent load is greater than 1.2 times the design load, operate according to mode A. At this time, control the aeration rate of the first reaction tank and the second reaction tank to 40% of the design value, and the aeration rate of the third reaction tank to 20% of the design value.

[0010] When 0.8 times the design load ≤ influent load ≤ 1.2 times the design load, operate according to mode A. At this time, control the aeration volume of the first reaction tank, the second reaction tank, and the third reaction tank to make them equal, and the total aeration volume is the design value.

[0011] When 0.4 times the design load ≤ the average value of the influent load over 10 consecutive days < 0.8 times the design load, operate according to mode B. At this time, close the aeration pipe of the first reaction tank, control the second and third reaction tanks to make their aeration volume equal, and the total aeration volume is the value calculated based on the consumption of oxygen-consuming pollutants.

[0012] When the average influent load over 10 consecutive days is less than 0.4 times the design load, the system operates according to mode C. In this case, the aeration pipes of the first and second reaction tanks are closed, and the aeration rate of the third reaction tank is calculated based on the consumption of oxygen-consuming pollutants.

[0013] In the above-mentioned method for stable operation control of a low-energy MBBR process system, in step c, when operating in mode C, if the effluent quality continuously increases for 3 consecutive days or 0.4 times the design load is less than or equal to the influent load for 3 consecutive days, switch to mode B operation. For the first 3 days after the mode switch, control the aeration rate of the second reaction tank to 20% of the design value, and the aeration rate of the third reaction tank to be calculated based on the consumption of oxygen-consuming pollutants. After 3 days, restore the aeration rates of the second and third reaction tanks to be the same, and the total aeration rate to be calculated based on the consumption of oxygen-consuming pollutants.

[0014] In the above-mentioned method for stable operation control of a low-energy MBBR process system, in step c, when operating in mode B, if the effluent quality continuously increases for 3 consecutive days or if 0.8 times the design load ≤ the influent load ≤ 1.2 times the design load for 3 consecutive days, then revert to mode A operation. For the first 3 days, control the aeration rate of the first reaction tank to 20% of the design value, the aeration rate of the second reaction tank to 40% of the design value, and the aeration rate of the third reaction tank to 40% of the design value. After 3 days, control the aeration rates of the first, second, and third reaction tanks to be the same, and the total aeration rate to the design value.

[0015] The above-mentioned method for stable operation control of a low-energy MBBR process system involves reverting to mode A for 2 days after continuous operation in mode B or mode C for more than 15 days without any change in the operating mode. If the influent load still does not change, then switch back to mode B or mode C for operation.

[0016] The aforementioned method for stable operation control of a low-energy MBBR process system includes a gate comprising a first gate, a second gate, and a third gate. The first gate is located between the first and second reaction tanks, the second gate is located between the second and third reaction tanks, and the third gate is located at the outlet of the third reaction tank. The first and second gates are unidirectional gates.

[0017] The above-mentioned method for stable operation control of a low-energy MBBR process system has the same tank volume for the first, second, and third reaction tanks.

[0018] The above-mentioned method for stable operation control of a low-energy MBBR process system includes a first valve, a third valve, and a fifth valve respectively installed on the main inlet pipes connected to the first, second, and third reaction tanks; a second valve is installed between the first and third valves on the main inlet pipes, and a fourth valve is installed between the third and fifth valves.

[0019] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0020] (1) This invention provides a method for stable operation control of a low-energy MBBR process system, which sets up three reaction tanks connected in sequence. Different operating modes can be realized through the valves set up. In the corresponding operating mode, the aeration volume is adjusted according to the influent load, thus realizing aeration adjustment under multiple operating modes.

[0021] (2) The MBBR process can be flexibly adjusted according to the actual influent water quality and quantity, with the goal of achieving the effluent standard, which reduces the waste of ineffective air volume and energy consumption.

[0022] (3) The water quality of each region of the present invention is relatively constant, the suspended carrier is always in a stable operating environment and is not affected by water quality changes, the biofilm is not affected, the bacterial community enrichment efficiency is high, and the effluent water quality is stable and meets the standards. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the present invention.

[0024] V1 - First reaction tank, V2 - Second reaction tank, V3 - Third reaction tank, F1 - First valve, F2 - Second valve, F3 - Third valve, F4 - Fourth valve, F5 - Fifth valve, W1 - First gate, W2 - Second gate, W3 - Third gate. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0026] It is understood that the connection relationships described in this application refer to direct or indirect connections. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components. For example, A can be directly connected to C, and C can be directly connected to B, thus achieving a connection between A and B through C. It is also understood that the "A connects to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0027] In the description of this application, the words "first," "second," etc., are used only to distinguish different objects and do not limit the quantity or order of execution, nor do they imply that they must be different. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0028] The technical solution of this application will be further described in detail below with reference to the accompanying drawings.

[0029] The technical concept of this invention is to reduce the energy consumption of the system by adjusting the aeration under multi-mode operating conditions in real time.

[0030] In this invention, the aeration rate is controlled by controlling the gate. The gate is used to adjust the opening of the aeration pipe to achieve the corresponding aeration rate.

[0031] like Figure 1 As shown, the low-energy MBBR process system of the present invention includes a first reaction tank V1, a second reaction tank V2, and a third reaction tank V3, all three reaction tanks having the same volume. A first gate W1 is installed between the first and second reaction tanks, a second gate W2 is installed between the second and third reaction tanks, and a third gate W3 is installed at the outlet of the third reaction tank. A first valve F1, a third valve F3, and a fifth valve F5 are respectively installed on the main inlet pipes connecting to the first, second, and third reaction tanks. A second valve F2 is installed between the first and third valves on the main inlet pipes, and a fourth valve F4 is installed between the third and fifth valves.

[0032] Preferably, the first gate and the second gate are unidirectional gates.

[0033] Example 1:

[0034] A wastewater treatment system is designed to treat 30,000 m³ of wastewater. 3 / d, designed influent ammonia nitrogen 30mg / L, effluent ammonia nitrogen 1.5mg / L. Design air volume 98Nm 3 / s. The aeration rate is adjusted according to the actual influent water quality, always operating in Mode A. In the initial stage, the aeration rate can be adjusted based on the actual influent water quality, at which point the energy consumption is 0.155~0.189 kWh / m³. 3 When the influent ammonia nitrogen level is lower than the actual value, the actual air supply decreases accordingly. However, the suspended carrier is difficult to fluidize, and the air volume has to be readjusted. When the influent ammonia nitrogen level is reduced from 20 mg / L to 10 mg / L, the energy consumption cannot be reduced further and remains at 0.127 kWh / m³. 3 At or above the required level. When the influent ammonia nitrogen is 20 mg / L, adjust to Mode B operation. At this time, shut off the airflow in the first reaction tank, and the overall energy consumption is reduced to 0.122 kWh / m³. 3 The energy consumption decreased by 3.94%; when the influent ammonia nitrogen continued to decrease to 15 mg / L, the energy consumption decreased to 0.089 mg / L, a reduction of 29.92%; when the influent ammonia nitrogen decreased to 10 mg / L, if mode B was continued, it would be difficult to reduce the energy consumption in order to maintain fluidization. At this time, switching to mode C reduced the energy consumption to 0.057 kWh / m³. 3 Compared with mode A, the energy consumption was reduced by 55.12%, and compared with mode B, it was reduced by 34.48%. The operating energy consumption values ​​of different modes under different influent water quality conditions in this embodiment are shown in Table 1.

[0035] Table 1

[0036]

[0037] As can be seen from Example 1, it adopts operating modes A, B, and C, and the system energy consumption can be reduced by controlling the aeration volume.

[0038] Example 2:

[0039] A wastewater treatment system with a treatment capacity of 100m³ 3 The design influent ammonia nitrogen concentration was 30 mg / L, and the designed effluent ammonia nitrogen concentration was 1.5 mg / L. Different operating modes were switched based on the actual influent water quality to achieve energy saving and consumption reduction. The recovery status of the first reaction tank was studied. It was found that when the suspended carrier was shut down for a long time, excessive fluidization intensity upon resumption of operation could easily cause biofilm detachment, affecting the treatment effect. Analysis of biofilm thickness and biomass under different aeration rates revealed that the changes in biofilm thickness and biomass were minimal when the aeration rate was restored to 20%, which is considered the optimal initial aeration rate for recovery. Table 2 shows the analysis of biofilm detachment under different aeration rates in this embodiment.

[0040] Table 2

[0041]

[0042] Example 3:

[0043] A wastewater treatment system with a treatment capacity of 500m³ 3 The design parameters were: influent ammonia nitrogen 50 mg / L, effluent ammonia nitrogen 1.5 mg / L, and different operating modes were switched based on the actual influent water quality to achieve energy saving and consumption reduction. Initially, mode A was used for over one year. As the influent water quality decreased, mode B was switched. The first reaction tank was subsequently shut down. Load measurements were periodically taken from the packing material in the first reaction tank to study performance recovery time. It was found that as the shutdown time increased, the biochemical performance of the biofilm in the first reaction tank decreased, and the time to recover to the initial value also gradually increased. The research results showed that a maximum shutdown of 15 days did not affect the stability of the effluent, regardless of the initial load or recovery time. However, if the shutdown exceeded 15 days, substrate replenishment was required for a period before shutdown to avoid adverse consequences from prolonged shutdown. The performance and recovery time of the biofilm under different shutdown periods in this embodiment are shown in Table 3.

[0044] Table 3

[0045]

[0046] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0047] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A method for stable operation control of a low-energy MBBR process system, characterized in that, The steps are as follows: a. The MBBR process system includes a first reaction tank, a second reaction tank, a third reaction tank, and auxiliary accessories arranged from front to back. The auxiliary accessories include gate valves, valves, and inlet pipes. Each reaction tank is equipped with an aeration pipe with an adjustable air volume design. Suspended carriers are added to all three reaction tanks. b. The MBBR system has three operating modes: Mode A, Mode B, and Mode C. The specific route of Mode A is: wastewater flows out after passing through the first reaction tank, the second reaction tank, and the third reaction tank; the specific route of Mode B is: wastewater flows out after passing through the second reaction tank and the third reaction tank; and the specific route of Mode C is: wastewater flows out after passing through the third reaction tank. c. When the influent load is greater than 1.2 times the design load, operate according to mode A. At this time, control the aeration rate of the first reaction tank and the second reaction tank to 40% of the design value, and the aeration rate of the third reaction tank to 20% of the design value. When 0.8 times the design load ≤ influent load ≤ 1.2 times the design load, operate according to mode A. At this time, control the aeration volume of the first reaction tank, the second reaction tank, and the third reaction tank to make them equal, and the total aeration volume is the design value. When 0.4 times the design load ≤ the average value of the influent load over 10 consecutive days < 0.8 times the design load, operate according to mode B. At this time, close the aeration pipe of the first reaction tank, control the second and third reaction tanks to make their aeration volume equal, and the total aeration volume is the value calculated based on the consumption of oxygen-consuming pollutants. When the average influent load over 10 consecutive days is less than 0.4 times the design load, the system operates according to mode C. In this case, the aeration pipes of the first and second reaction tanks are closed, and the aeration rate of the third reaction tank is calculated based on the consumption of oxygen-consuming pollutants.

2. The method for stable operation control of a low-energy MBBR process system according to claim 1, characterized in that: In step c, when operating in mode C, if the effluent quality continues to rise for 3 consecutive days or if 0.4 times the design load is less than or equal to the influent load for 3 consecutive days, switch to mode B. For the first 3 days after the mode switch, control the aeration rate of the second reaction tank to 20% of the design value, and the aeration rate of the third reaction tank to be calculated based on the consumption of oxygen-consuming pollutants. After 3 days, restore the aeration rates of the second and third reaction tanks to be the same, and the total aeration rate to be calculated based on the consumption of oxygen-consuming pollutants.

3. The method for stable operation control of a low-energy MBBR process system according to claim 2, characterized in that: In step c, when operating in mode B, if the effluent quality continues to rise for 3 consecutive days or if 0.8 times the design load ≤ the influent load ≤ 1.2 times the design load for 3 consecutive days, then switch to mode A. For the first 3 days, control the aeration rate of the first reaction tank to 20% of the design value, the aeration rate of the second reaction tank to 40% of the design value, and the aeration rate of the third reaction tank to 40% of the design value. After 3 days, control the aeration rates of the first, second, and third reaction tanks to be the same, and the total aeration rate to the design value.

4. The method for stable operation control of a low-energy MBBR process system according to claim 1, characterized in that: If the operation mode remains unchanged after running continuously for more than 15 days in mode B or mode C, then switch back to mode A for 2 days. If the influent load still does not change, then switch back to mode B or mode C.

5. The method for stable operation control of a low-energy MBBR process system according to claim 1, characterized in that: The gate includes a first gate, a second gate, and a third gate. The first gate is located between the first reaction tank and the second reaction tank, the second gate is located between the second reaction tank and the third reaction tank, and the third gate is located at the outlet of the third reaction tank. The first gate and the second gate are one-way gates.

6. The method for stable operation control of a low-energy MBBR process system according to claim 1, characterized in that: The first, second, and third reaction tanks have the same volume.

7. The method for stable operation control of a low-energy MBBR process system according to claim 1, characterized in that: A first valve, a third valve, and a fifth valve are respectively installed on the main inlet pipes connected to the first reaction tank, the second reaction tank, and the third reaction tank; a second valve is installed between the first valve and the third valve on the main inlet pipe, and a fourth valve is installed between the third valve and the fifth valve.

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