Membrane-method community sewage recycling device and recycling method

Abstract

The invention belongs to the field of sewage treatment, and particularly relates to a membrane-method community sewage recycling device and method. The membrane-method community sewage recycling device comprises a pretreatment unit for pretreating sewage; the biochemical treatment unit is used for carrying out biochemical treatment on the sewage so as to degrade organic matters and remove nitrogen and phosphorus; the MBR membrane tank unit is used for carrying out membrane separation on the sludge-water mixed liquid treated by the biochemical treatment unit, producing clear liquid and intercepting activated sludge; and the disinfection unit is used for disinfecting clean water generated by the MBR membrane tank unit. The method has the beneficial effects of high efficiency, stability and energy conservation and recycling. Integration is convenient, and the method is especially suitable for communities with limited spaces.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, specifically relating to a membrane-based community wastewater reuse device and method. Background Technology

[0002] With the continuous advancement of new rural construction in my country, the rural domestic sewage discharge pattern has gradually shifted from a scattered state to an intensive one. Centralized treatment and reuse of domestic sewage can effectively reduce the pollution caused by direct sewage discharge to surrounding natural water systems.

[0003] Rural domestic sewage is mainly treated using traditional decentralized sewage treatment methods, employing small-scale local treatment units. Common sewage treatment methods include septic tanks, constructed wetlands, and stabilization ponds, which utilize the photosynthetic action of algae and the anaerobic decomposition by microorganisms to treat rural sewage.

[0004] Traditional decentralized wastewater treatment methods, such as septic tanks, constructed wetlands, and stabilization ponds, are based on natural ecological technologies and are constructed in combination with the local environment. Due to their low construction and operation costs, minimal site requirements, and ability to flexibly adapt to different rural layouts, they have a high application rate in rural my country. However, with the construction of new rural areas, their disadvantages, such as low treatment capacity and efficiency, significant influence of natural conditions on treatment effects, and poor nitrogen and phosphorus removal, have gradually become apparent, making them unsuitable for clustered rural construction. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a membrane-based community wastewater reuse device and reuse method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A membrane-based community wastewater reuse device includes:

[0008] The pretreatment unit pre-treats the wastewater;

[0009] The biological treatment unit performs biological treatment on wastewater to degrade organic matter and remove nitrogen and phosphorus.

[0010] The MBR membrane tank unit separates the sludge-water mixture after the biological treatment unit through membrane separation, producing clear liquid and retaining activated sludge.

[0011] And a disinfection unit to disinfect the clean water produced by the MBR membrane tank unit.

[0012] Preferably, the preprocessing unit includes:

[0013] A bar screen is used for pretreatment of wastewater to remove sludge.

[0014] Security filters are used for the precise filtration of wastewater.

[0015] Preferably, a water storage tank is provided between the pretreatment unit and the biochemical treatment unit; the biochemical treatment unit is an inverted A-type unit. 2 / O processing tank.

[0016] Preferably, the reuse device is placed in an integrated box.

[0017] Preferably, the MBR membrane tank unit includes an MBR membrane tank and a sludge tank connected to the membrane tank.

[0018] Preferably, the supernatant water from the sewage tank is returned to the screen for slag removal.

[0019] This invention also includes a membrane-based community wastewater reuse method, employing the aforementioned membrane-based community wastewater reuse device; comprising the following steps:

[0020] S1: Pre-treatment is performed using the aforementioned pre-treatment unit, allowing the community domestic sewage to undergo secondary physical filtration by passing through a bar screen and a security filter in sequence to remove suspended solids;

[0021] S2: Perform biochemical treatment using the aforementioned biochemical treatment unit, employing an inverted A... 2 The / O process involves sequentially performing hypoxic, anaerobic, and aerobic reactions.

[0022] S3: Using an MBR membrane tank unit for membrane separation, the biochemically treated mud-water mixture is sent into a membrane bioreactor equipped with a hollow fiber ultrafiltration membrane module for solid-liquid separation to obtain ultrafiltration permeate.

[0023] S4: The ultrafiltration permeate is disinfected and reused using the disinfection unit.

[0024] Preferably, in step S2, the inverted A 2 The hydraulic retention time of the / O process unit is 3 hours in the anoxic zone, 6 hours in the anaerobic zone, and 8 hours in the aerobic zone. In the aerobic zone, the dissolved oxygen concentration in the wastewater is controlled at 2-3 mg / L, and the sludge concentration is controlled at 4000-5000 mg / L. Preferably, in the anoxic zone, sodium acetate is added as a carbon source at a dosage of 40-80 mg / L, preferably 60 mg / L.

[0025] Preferably, the hollow fiber ultrafiltration membrane is a curtain-type braided tube reinforced membrane module, with a single membrane area of ​​not less than 20 m2, an operating flux of not more than 200 LMH, a retention accuracy of 0.03 microns, and a transmembrane pressure difference of 0.05 MPa; the sludge concentration in the membrane bioreactor is controlled at 6000-8000 mg / L.

[0026] Compared with existing decentralized wastewater treatment technologies, this invention adopts an integrated process of "pretreatment + biochemical treatment + MBR + disinfection". The beneficial effects of this invention are:

[0027] 1. High efficiency and stability: Combining the high efficiency of biological and membrane methods, the effluent water quality is excellent and stable, and it has strong resistance to shock loads.

[0028] 2. Energy saving and reuse: Deeply treated wastewater can be reused as a resource, saving water resources.

[0029] 3. Convenient integration: The modular and container-style design greatly reduces the floor space required, making it easy to transport and install, and is especially suitable for communities with limited space. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a membrane-based community wastewater reuse device. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments.

[0032] Figure 1 A membrane-based community wastewater reuse device is shown, comprising:

[0033] The pretreatment unit pretreats wastewater; it includes a bar screen for removing sludge from the wastewater and a security filter for precision filtration of the wastewater.

[0034] The biochemical treatment unit treats wastewater to degrade organic matter and remove nitrogen and phosphorus; a water storage tank is provided between the pretreatment unit and the biochemical treatment unit.

[0035] The MBR membrane tank unit performs membrane separation on the sludge-water mixture after treatment by the biological treatment unit, producing a clear liquid and retaining activated sludge. The MBR membrane tank unit includes an MBR membrane tank and a sludge discharge tank connected to the membrane tank. The supernatant from the sludge discharge tank is returned to a screen for sludge removal.

[0036] And a disinfection unit to disinfect the clean water produced by the MBR membrane tank unit.

[0037] As one form, the recycling device is placed in an integrated box for easy transportation and operation.

[0038] This invention also includes a membrane-based community wastewater reuse method, employing the aforementioned membrane-based community wastewater reuse device; comprising the following steps:

[0039] S1: Pre-treatment is performed using the aforementioned pre-treatment unit, allowing the community domestic sewage to undergo secondary physical filtration by passing through a bar screen and a self-cleaning filter in sequence to remove suspended solids;

[0040] S2: Biochemical treatment is carried out using the aforementioned biochemical treatment unit, employing an inverted A2 / O process, sequentially performing anoxic, anaerobic, and aerobic reactions; the hydraulic retention time of the anoxic section of the inverted A2 / O process unit is 3 hours, the hydraulic retention time of the anaerobic section is 6 hours, and the hydraulic retention time of the aerobic section is 8 hours; in the aerobic section, the dissolved oxygen concentration of the wastewater is controlled at 2-3 mg / L, and the sludge concentration is controlled at 4000-5000 mg / L; in the preferred anoxic section, sodium acetate is added as a carbon source at a dosage of 40-80 mg / L, preferably 60 mg / L.

[0041] S3: Using an MBR membrane tank unit for membrane separation, the biochemically treated sludge-water mixture is fed into a membrane bioreactor equipped with a hollow fiber ultrafiltration membrane module for solid-liquid separation to obtain ultrafiltration permeate; the hollow fiber ultrafiltration membrane is a curtain-type braided tube reinforced membrane module, with a single membrane area of ​​not less than 20 m2, an operating flux of not more than 200 LMH, a rejection accuracy of 0.03 microns, and a transmembrane pressure difference of 0.05 MPa; the sludge concentration in the membrane bioreactor is controlled at 6000-8000 mg / L.

[0042] S4: The ultrafiltration permeate is disinfected and reused using the disinfection unit.

[0043] The following is a description using specific examples.

[0044] Example 1: A membrane-based method for community wastewater reuse, comprising the following steps:

[0045] S1: The wastewater is introduced into the system by a lift pump. Large particles of impurities are initially intercepted by a basket screen with a precision of 10 mm. Then, it is further filtered by a self-cleaning security filter with a precision of 20 microns to ensure that no large-diameter floating objects and impurities enter the subsequent process. The wastewater suspended solids removal rate is ≥90%.

[0046] S2: After pretreatment, the wastewater enters the storage tank for a short period of time, and is then introduced into the inverted A by a booster pump. 2 The combined O / O treatment tank has a wastewater mixing time of 3 hours in the anoxic zone, during which 60 mg / L of sodium acetate is added to enhance the denitrification process, achieving a total nitrogen removal rate of ≥85%. The mixing time in the anaerobic zone is 6 hours, and the aeration time in the aerobic zone is 8 hours. The dissolved oxygen in the wastewater is controlled to be 2-3 mg / L and the sludge concentration is 4000-5000 mg / L through aeration.

[0047] S3: The biochemical effluent enters four curtain-type MBR modules made of braided tube reinforced hollow fiber ultrafiltration membranes, with each module having a membrane area of ​​20m². 2The ultrafiltration process achieves a flux of 200 LMH, a retention accuracy of 0.03 microns, a transmembrane pressure differential of 0.05 MPa, and a sludge concentration of 6000-8000 mg / L; the permeate concentration is ≥30 mJ / cm³. 2 After ultraviolet disinfection, the waste is discharged and reused.

[0048] The influent ammonia nitrogen level was measured at 60 mg / L, and the product ammonia nitrogen level was measured at 0.57 mg / L. The product ammonia nitrogen levels meet the relevant requirements of the "Water Quality Standard for Urban Wastewater Reuse for Miscellaneous Uses" (GB / T 18920-2020).

[0049] In summary, the technical solution of the present invention has the following characteristics:

[0050] 1. High efficiency and stability: Combining the high efficiency of biological and membrane methods, the effluent water quality is excellent and stable, and it has strong resistance to shock loads.

[0051] 2. Energy saving and reuse: Deeply treated wastewater can be reused as a resource, saving water resources.

[0052] 3. Convenient integration: The modular and container-style design greatly reduces the floor space required, making it easy to transport and install, and is especially suitable for communities with limited space.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A membrane-based community wastewater reuse device, characterized in that, include: The pretreatment unit pre-treats the wastewater; The biological treatment unit performs biological treatment on wastewater to degrade organic matter and remove nitrogen and phosphorus. The MBR membrane tank unit separates the sludge-water mixture after the biological treatment unit through membrane separation, producing clear liquid and retaining activated sludge. And a disinfection unit to disinfect the clean water produced by the MBR membrane tank unit.

2. The membrane-based community wastewater reuse device according to claim 1, characterized in that, The preprocessing unit includes: A bar screen is used for pretreatment of wastewater to remove sludge. Security filters are used for the precise filtration of wastewater.

3. The membrane-based community wastewater reuse device according to claim 1, characterized in that, A water storage tank is provided between the pretreatment unit and the biochemical treatment unit; the biochemical treatment unit is an inverted A-type unit. 2 / O processing tank.

4. The membrane-based community wastewater reuse device according to claim 1, characterized in that, The aforementioned recycling device is placed in an integrated box.

5. The membrane-based community wastewater reuse device according to claim 1, characterized in that, The MBR membrane tank unit includes an MBR membrane tank and a sludge tank connected to the membrane tank.

6. The membrane-based community wastewater reuse device according to claim 5, characterized in that, The supernatant water from the sewage tank is returned to the screen for slag removal.

7. A membrane-based method for community wastewater reuse, characterized in that, The membrane-based community wastewater reuse device according to any one of claims 1-6 is adopted; Includes the following steps: S1: Pre-treatment is performed using the aforementioned pre-treatment unit, allowing the community domestic sewage to undergo secondary physical filtration by passing through a screen and a security device in sequence to remove suspended solids; S2: Perform biochemical treatment using the aforementioned biochemical treatment unit, employing an inverted A... 2 The / O process involves sequentially performing hypoxic, anaerobic, and aerobic reactions. S3: Using an MBR membrane tank unit for membrane separation, the biochemically treated mud-water mixture is sent into a membrane bioreactor equipped with a hollow fiber ultrafiltration membrane module for solid-liquid separation to obtain ultrafiltration permeate. S4: The ultrafiltration permeate is disinfected and reused using the disinfection unit.

8. The membrane-based community wastewater reuse method according to claim 7, characterized in that, In step S2, the inverted A 2 The hydraulic retention time of the / O process unit is 3 hours in the anoxic zone, 6 hours in the anaerobic zone, and 8 hours in the aerobic zone. In the aerobic zone, the dissolved oxygen concentration in the wastewater is controlled at 2-3 mg / L, and the sludge concentration is controlled at 4000-5000 mg / L. Preferably, in the anoxic zone, sodium acetate is added as a carbon source at a dosage of 40-80 mg / L, preferably 60 mg / L.

9. The membrane-based community wastewater reuse method according to claim 7, characterized in that, The hollow fiber ultrafiltration membrane is a curtain-type braided tube reinforced membrane module, with a single membrane area of ​​not less than 20m². 2 The operating flux is no higher than 200 LMH, the retention accuracy is 0.03 microns, and the transmembrane pressure difference is 0.05 MPa; the sludge concentration in the membrane bioreactor is controlled at 6000-8000 mg / L.

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