MBR (Membrane Biological Reactor) backwashing system capable of saving occupied area

Abstract

The utility model discloses a land-saving MBR (Membrane Bioreactor) backwashing system, which relates to the technical field of MBR sewage treatment, comprises a water production system, and is characterized in that the water production system is communicated with a backwashing system and a chemical enhanced backwashing system; the backwashing system consists of a backwashing water absorption pipeline, a backwashing centrifugal pump, a backwashing water pressing pipeline and a plurality of backwashing branch pipes; the chemical enhanced backwash system comprises acid enhanced backwash and alkali enhanced backwash, the acid enhanced backwash is used for carrying out acid backwash on the water production system, and the alkali enhanced backwash is used for carrying out alkali backwash on the water production system. The MBR backwashing system provided by the utility model is simple in structure, convenient to use and compact in system, and is particularly suitable for the design of a large full-buried MBR system, the original old process and the condition that MBR transformation is adopted in shortage of occupied space.

Description

Technical Field

[0001] This utility model relates to the field of MBR wastewater treatment technology, and in particular to a space-saving MBR backwashing system. Background Technology

[0002] MBR, also known as membrane bioreactor, is an emerging water treatment technology that combines bioreactor and membrane filtration technology. In the past decade, the MBR process has been widely used worldwide due to its minimal footprint and reusable effluent quality.

[0003] The challenge of operating an MBR process lies in controlling membrane fouling. Flocculent sludge in the sludge mixture easily adheres to the membrane surface, eventually forming a gel layer that gradually reduces the membrane's filtration flux. Backwashing is one of the most fundamental fouling control methods in MBR operation, and it is typically embedded in the MBR's operating procedure on a periodic basis.

[0004] Generally, the backwash water for MBR is the system's production water. Therefore, the backwashing system needs to be equipped with a reclaimed water tank and a backwash water pump at the MBR's outlet. The suction and discharge pipes of the backwash water pump are connected to the reclaimed water tank and the MBR's production water pipe, respectively. Through the operation of the backwash water pump and the switching of pneumatic valves, the water in the reclaimed water tank is driven in reverse from inside the MBR membrane into the MBR's reaction tank, thereby achieving the flushing and elution of contaminants on the MBR membrane surface and in the membrane pores.

[0005] In practical applications, the following problems may arise when setting up a reclaimed water tank: Firstly, the tank's volume needs to be larger than the volume of water required for a single backwash of all MBR membrane modules at maximum flow rate. This will result in high infrastructure costs for new projects and renovations of existing structures. Secondly, reclaimed water tanks pose certain safety hazards; careless operation by on-site personnel can lead to contamination of the reclaimed water, which can exacerbate membrane fouling during backwashing and even cause irreversible damage. Furthermore, long-term water storage in the tank makes it prone to algae or microorganism growth. Therefore, a security filter or other backwash water filtration facility must be added to the actual backwashing system. This increases equipment footprint and consumable replacement costs; additionally, the security filter requires high precision and regular manual maintenance and cleaning. Finally, the backwashing process requires real-time level monitoring of the reclaimed water tank and interlocking with the backwash pump and pneumatic valves, increasing the demands on instrumentation and system control.

[0006] In conclusion, the simplification of the cleaning tank and backwashing system is of great significance for the further promotion of MBR technology, especially for large-scale fully underground sewage treatment plants, existing old processes, and situations where MBR retrofitting is adopted due to limited land.

[0007] The current method omits the reclaimed water tank by replacing the traditional centrifugal pump with a bidirectional lobe rotor pump. Relying on the reverse discharge function of the lobe rotor pump, backwashing is achieved using product water from the main product water pipe, allowing both product water production and backwashing functions to be performed on the same pipeline. However, the self-priming performance of the lobe rotor pump is closely related to the wear-resistant and corrosion-resistant rotor, making the equipment more technically demanding than traditional centrifugal pumps. Currently, lobe rotor pumps are mostly imported brands, resulting in high equipment prices. Furthermore, compatibility with the MBR membrane system must be considered before selecting a lobe rotor pump.

[0008] For example, the patent with authorization announcement number CN208878303U discloses a novel MBR hydraulic backwashing system. This system directly utilizes the running permeate pumps and their permeate to backwash individual membrane modules that are not in operation, through the control and switching of multiple sets of permeate pumps and pneumatic valves, eliminating the need for a backwash pump and a reclaimed water tank. However, directly using permeate pumps for backwashing makes it difficult to control the backwash flow rate and cannot guarantee the backwash water pressure, and is highly limited by the characteristics of the system piping and permeate pumps. Nevertheless, the advantages of the aforementioned patent in saving space and simplifying the backwashing system are undeniable and worth learning from, and further optimization is warranted to improve its operability and broaden its application scenarios.

[0009] Equally important, the backwashing system requires certain control logic to ensure a stable water volume during the backwashing process, that is, the flow rate of the main water production pipe always meets the demand for backwashing water volume during the backwashing process. To this end, we propose an MBR backwashing system that saves space. Utility Model Content

[0010] The purpose of this utility model is to provide a space-saving MBR backwashing system. The provided MBR backwashing system has a simple structure, is easy to use, and is compact. It is particularly suitable for the design of large-scale fully buried MBR systems, existing old processes, and situations where MBR retrofitting is adopted due to limited space.

[0011] To achieve the above objectives, this utility model provides the following technical solution: a space-saving MBR backwashing system, including a water production system, wherein the water production system is connected to a backwashing system and a chemically enhanced backwashing system;

[0012] The backwashing system consists of a backwashing suction pipe, a backwashing centrifugal pump, a backwashing pressurization pipe, and multiple backwashing branch pipes;

[0013] The chemically enhanced backwashing system includes acid-enhanced backwashing and alkali-enhanced backwashing. The acid-enhanced backwashing is used to perform acid backwashing on the product water system, and the alkali-enhanced backwashing is used to perform alkaline backwashing on the product water system.

[0014] Preferably, the water production system includes three or more MBR membrane modules operating in parallel. Each MBR membrane module consists of an MBR membrane tank, several submerged MBR membrane modules filled with MBR hollow fiber membrane filaments, a water intake pipe, a water production centrifugal pump, and a water discharge pipe.

[0015] Preferably, a pneumatic butterfly valve for water production is installed on the water suction pipe, and an electromagnetic flow meter for water production is installed on the water discharge pipe.

[0016] Preferably, each pressurized water pipe of the water production system is connected to the main water production pipe, and the main water production pipe is equipped with a total water production electromagnetic flow meter.

[0017] Preferably, the backwash suction pipe is connected before the main product water electromagnetic flow meter in the product water main pipe, the backwash pressure pipe is equipped with a backwash electromagnetic flow meter at its front end, and the backwash pressure pipe is connected to the suction pipe of each MBR membrane module in the product water system through a backwash branch pipe. A backwash pneumatic butterfly valve is installed on the backwash branch pipe.

[0018] Preferably, the chemically enhanced backwashing system includes a storage tank, a dosing pipeline connected to the storage tank, and a dosing metering pump connected to the dosing pipeline. The dosing pipeline is equipped with a dosing pneumatic ball valve, and the end of the dosing pipeline is connected to a backwashing pipeline mixer.

[0019] Preferably, a pneumatic butterfly valve for water production is installed on the water intake pipe, and an electromagnetic flow meter for water production is installed on the water discharge pipe. The end of the water discharge pipe of the water production system is connected to the main water production pipe, and a main electromagnetic flow meter for total water production is installed on the main water production pipe.

[0020] The technical effects and advantages of this utility model are as follows:

[0021] (1) This backwashing system does not require a backwashing tank, reducing civil engineering and plant area, effectively reducing the cost and infrastructure investment of the entire sewage treatment system.

[0022] (2) Using real-time produced water in the pipeline for backwashing can avoid the backwash water pollution problem caused by long-term storage in the clear water tank. At the same time, it also eliminates the need for the security filter required by the normal backwashing system, greatly reducing management difficulty and manpower input.

[0023] (3) The backwashing system omits the backwash water security filter and simplifies the backwashing pipeline, thus reducing system costs and reducing backwash water pressure loss to a certain extent, while ensuring backwashing effect.

[0024] (4) The backwashing process can be automated by PLC program control, which reduces manual operation and facilitates maintenance. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the MBR backwashing system of this utility model.

[0026] Figure 2 This is a schematic diagram of the control program structure of the MBR backwashing system of this utility model.

[0027] In the diagram: 1. MBR membrane tank; 2. MBR hollow fiber membrane filaments; 3. Submerged MBR membrane module; 4. Suction pipe; 5. Permeate water pneumatic butterfly valve; 6. Permeate water centrifugal pump; 7. Permeate water electromagnetic flow meter; 8. Pressurized water pipe; 9. Permeate water main pipe; 10. Main permeate water electromagnetic flow meter; 11. Backwash suction pipe; 12. Backwash centrifugal pump; 13. Backwash electromagnetic flow meter; 14. Backwash pressurized water pipe; 15. Backwash branch pipe; 16. Backwash pneumatic butterfly valve; 17. Chemical storage tank; 18. Chemical dosing pipe; 19. Chemical dosing metering pump; 20. Chemical dosing pneumatic ball valve; 21. Pipeline mixer. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] This utility model provides, for example Figure 1-2 The illustrated space-saving MBR backwashing system includes a permeate system connected to a backwashing system and a chemically enhanced backwashing system. The backwashing system consists of a backwashing suction pipe 11, a backwashing centrifugal pump 12, a backwashing pressurized water pipe 14, and multiple backwashing branch pipes 15. The chemically enhanced backwashing system includes acid-enhanced backwashing and alkali-enhanced backwashing. Acid-enhanced backwashing is used to perform acid backwashing on the permeate system, and alkali-enhanced backwashing is used to perform alkaline backwashing on the permeate system. The MBR membrane module is backwashed through the coordination of the backwashing system, acid-enhanced backwashing, and alkali-enhanced backwashing.

[0030] It should be further explained that the permeate system includes three or more MBR membrane modules operating in parallel. Each MBR membrane module consists of an MBR membrane tank 1, several submerged MBR membrane modules 3 filled with MBR hollow fiber membrane filaments 2, a suction pipe 4, a permeate centrifugal pump 6, and a discharge pipe 8. A permeate pneumatic butterfly valve 5 is installed on the suction pipe 4, and a permeate electromagnetic flow meter 7 is installed on the discharge pipe 8. The discharge pipe 8 of the permeate system is connected to the permeate main pipe 9, and a main permeate electromagnetic flow meter 10 is installed on the permeate main pipe 9.

[0031] Furthermore, each pressurized water pipe 8 of the water production system is connected at its end to the main water production pipe 9, which is equipped with a main water production electromagnetic flow meter 10.

[0032] It should be noted that the backwash suction pipe 11 is connected before the main product water electromagnetic flow meter 10 of the product water main pipe 9, the backwash pressure pipe 14 is equipped with a backwash electromagnetic flow meter 13 at the front end, and the backwash pressure pipe 14 is connected to the suction pipe 4 of each MBR membrane module in the product water system through the backwash branch pipe 15. The backwash branch pipe 15 is equipped with a backwash pneumatic butterfly valve 16.

[0033] Furthermore, the chemical-enhanced backwashing system includes a storage tank 17, a dosing pipeline 18 connected to the storage tank 17, and a dosing metering pump 19 connected to the dosing pipeline 18. The dosing pipeline 18 is equipped with a dosing pneumatic ball valve 20, and the end of the dosing pipeline 18 is connected to the backwashing pipeline mixer 21.

[0034] This embodiment uses the backwashing process of MBR membrane module A as an example for illustration:

[0035] After the permeate program of Group A starts, the permeate pneumatic butterfly valve 5 will switch to the open state, and then the permeate centrifugal pump 6 will run. The negative pressure generated by the permeate centrifugal pump 6 causes the sludge mixture in the MBR membrane tank 1 to be filtered through the MBR hollow fiber membrane filaments 2 of the submerged MBR membrane module 3 and collected into the suction pipe 4. It is then further transported by the permeate centrifugal pump 6 to the permeate pressure pipe 8. The instantaneous permeate flow rate of Group A can be read by the permeate electromagnetic flow meter 7 on the pressure pipe 8. The permeate systems of the other groups are the same as above. The permeate from all permeate systems is collected in the permeate main pipe 9. The instantaneous permeate flow rate of the entire MBR system can be read by the total permeate electromagnetic flow meter 10 on the permeate main pipe 9.

[0036] When Group A needs backwashing, first turn off the pneumatic butterfly valve 5 and centrifugal pump 6 of Group A. Then, turn off the pneumatic butterfly valve 16 of Group A and start the backwash centrifugal pump 12. After the backwash centrifugal pump 12 starts running, the negative pressure generated causes the water in the main permeate pipe 9 to be drawn into the backwash suction pipe 11. Then, through the backwash pressure pipe 14 and the backwash branch pipe 15, the backwash water is delivered to the suction pipe 4 of the group to be cleaned. Finally, it is sprayed out from inside the hollow fiber membrane filaments 2 of the MBR into the MBR membrane tank 1, realizing the backwashing process of Group A.

[0037] The above backwashing process can be implemented through a PLC automatic control program, including the following steps:

[0038] Step 1: Startup Condition Counting: Record the cycle / duration of water production process in Group A. Once the cumulative water production cycle / duration of Group A reaches the backwash requirement, the backwash preparation procedure begins.

[0039] Step 2: Backwash Self-Check: Check the permeate flow rate of Group A and the total permeate flow rate of the entire MBR system. If the remaining flow rate after subtracting the permeate flow rate of Group A from the total MBR permeate flow rate is greater than the preset backwash flow rate, the backwash procedure will begin. If the remaining flow rate does not meet the backwash flow rate requirement, Group A's permeate flow program will be extended, and it will enter a waiting state until the backwash flow rate requirement is met. Specifically, it is not recommended that the preset backwash flow rate exceed the sum of the permeate flow rates of the two groups.

[0040] Step 3: Entering the backwashing procedure: At this time, among the groups other than Group A, those currently producing water will maintain their water production status. The rest will continue to execute the procedure. If, during the backwashing process of Group A, other groups reach the backwashing conditions in terms of water production time / cycle, they will be queued in a registration manner, and the water production process will be extended.

[0041] Step 4: Backwash Start Control: The PLC sends a shut-off signal sequentially to the Group A product water centrifugal pump 6 and the Group A product water pneumatic butterfly valve 5. Then, it sends an open signal sequentially to the Group A backwash pneumatic butterfly valve 16 and the backwash centrifugal pump 12. The backwash program begins timing.

[0042] Step 5, Backwash End Control: When the backwash timer ends, the PLC sends a shutdown signal sequentially to the backwash centrifugal pump 12 and the backwash pneumatic butterfly valve 16 of Group A. Then, it sends a shutdown signal sequentially to the product water pneumatic butterfly valve 5 and the product water centrifugal pump 6 of Group A.

[0043] Step 6, Program Resumption: Group A begins resuming its permeate program, while the remaining membrane units with extended permeate production continue their programs. Units that meet the backwashing requirements during Group A's backwashing process cease their registration process and begin the same backwashing procedure as Group A. If multiple units are waiting for backwashing, the backwashing procedure is executed according to their registration priority.

[0044] When Group A requires acid or alkali-enhanced backwashing, the above backwashing procedure is executed and the corresponding dosing metering pump 19 and dosing pneumatic ball valve 20 are automatically opened. The agent is then evenly mixed into the backwashing water in the backwashing pipeline through the pipeline mixer 21 to achieve the chemical-enhanced backwashing process.

[0045] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A space-saving MBR backwashing system, comprising a product water system, characterized in that, The water production system is connected to a backwashing system and a chemically enhanced backwashing system; The backwashing system consists of a backwashing suction pipe (11), a backwashing centrifugal pump (12), a backwashing pressurized water pipe (14), and multiple backwashing branch pipes (15); The chemically enhanced backwashing system includes acid-enhanced backwashing and alkali-enhanced backwashing. The acid-enhanced backwashing is used to perform acid backwashing on the product water system, and the alkali-enhanced backwashing is used to perform alkaline backwashing on the product water system.

2. The space-saving MBR backwashing system according to claim 1, characterized in that, The water production system includes three or more MBR membrane modules operating in parallel. Each MBR membrane module consists of an MBR membrane tank (1), several submerged MBR membrane modules (3) filled with MBR hollow fiber membrane filaments (2), a water intake pipe (4), a water production centrifugal pump (6), and a water discharge pipe (8).

3. The space-saving MBR backwashing system according to claim 2, characterized in that, A pneumatic butterfly valve (5) for producing water is installed on the water suction pipe (4), and an electromagnetic flow meter (7) for producing water is installed on the water pressure pipe (8).

4. The space-saving MBR backwashing system according to claim 1, characterized in that, Each pressurized water pipe (8) of the water production system is connected at its end to the main water production pipe (9), and the main water production pipe (9) is equipped with a main water production electromagnetic flow meter (10).

5. The space-saving MBR backwashing system according to claim 1, characterized in that, The backwash suction pipe (11) is connected before the main product water electromagnetic flow meter (10) of the main product water pipe (9). The backwash pressure pipe (14) is equipped with a backwash electromagnetic flow meter (13) at the front end. The backwash pressure pipe (14) is connected to the suction pipe (4) of each MBR membrane module in the product water system through a backwash branch pipe (15). A backwash pneumatic butterfly valve (16) is installed on the backwash branch pipe (15).

6. The space-saving MBR backwashing system according to claim 1, characterized in that, The chemical-enhanced backwashing system includes a storage tank (17), a dosing pipeline (18) connected to the storage tank (17), and a dosing metering pump (19) connected to the dosing pipeline (18). The dosing pipeline (18) is equipped with a dosing pneumatic ball valve (20), and the end of the dosing pipeline (18) is connected to the backwashing pipeline mixer (21).

7. The space-saving MBR backwashing system according to claim 3, characterized in that, The end of the pressurized water pipe (8) of the water production system is connected to the main water production pipe (9), and the main water production pipe (9) is equipped with a main water production electromagnetic flow meter (10).

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