Anaerobic membrane bioreactor, sewage treatment system and use method thereof

Abstract

The invention belongs to the field of separation, and particularly relates to an anaerobic membrane bioreactor, a sewage treatment system and a use method of the anaerobic membrane bioreactor. The anaerobic membrane bioreactor comprises a membrane tank, a hydrophobic membrane assembly arranged in the membrane tank and a hydrophilic ultramicro filter membrane assembly; the hydrophobic membrane component is communicated with a membrane aeration gas inlet pipe and a membrane aeration tail gas discharge pipe; the ultramicro filter membrane assembly is communicated with the water producing pipe; and the ultramicro filter membrane assembly is communicated with a backwashing water pipe. According to the anaerobic membrane bioreactor disclosed by the invention, solid-liquid separation of an ultramicro filter membrane can be combined with anaerobic biological treatment, and high-concentration and refractory organic matters in sewage are degraded by utilizing anaerobic microorganisms, so that the effluent quality and the treatment efficiency are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of separation, and particularly relates to an anaerobic membrane bioreactor, a sewage treatment system and a use method thereof. BACKGROUND

[0002] Membrane bioreactor (MBR) technology is a kind of high-efficiency sewage treatment technology combining membrane separation technology and biological treatment unit, which can effectively improve the effluent quality and treatment efficiency. MBR technology mainly utilizes microorganisms to degrade organic matter in sewage, and realizes mud-water separation through a membrane assembly (usually microfiltration or ultrafiltration membrane). Its advantages are as follows: replacing the secondary sedimentation tank, effectively removing suspended solids, pathogens and the like, and having excellent effluent quality; small land occupation, high concentration of sludge (MLSS) can be maintained in the reactor; low sludge yield and long sludge age; flexible and stable operation, and strong anti-shock load capacity. In the field of municipal sewage treatment and reuse, MBR is mainly used for capacity expansion, production of reclaimed water, and has been widely applied, and has become an important technology in the field of sewage treatment and reuse.

[0003] At present, MBR mainly adopts air aeration to solve the membrane pollution problem in the operation process, so as to ensure the long-term stable operation of the MBR facility. However, this results in a high concentration of dissolved oxygen in the water body, which cannot realize or limit the anaerobic biochemical process, thereby affecting the effluent water quality. In addition, there are research reports on using hydraulic plug flow to flush the membrane wire, but the operation mechanism is complex, and the effect of controlling membrane pollution is also limited. SUMMARY

[0004] The present application aims to overcome the shortcomings in the prior art, and provides an anaerobic membrane bioreactor, a sewage treatment system and a use method thereof.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] An anaerobic membrane bioreactor comprises a membrane tank, a hydrophobic membrane assembly and a hydrophilic ultrafiltration membrane assembly arranged in the membrane tank; the hydrophobic membrane assembly is in communication with a membrane aeration gas inlet pipe and a membrane aeration tail gas discharge pipe; the hydrophilic ultrafiltration membrane assembly is in communication with a water production pipe; and the hydrophilic ultrafiltration membrane assembly is in communication with a backwashing water pipe.

[0007] An air aeration structure is arranged at the bottom of the membrane tank.

[0008] The hydrophobic membrane assembly and the hydrophilic ultrafiltration membrane assembly are independently multiple groups; and the hydrophobic membrane assembly and the hydrophilic ultrafiltration membrane assembly are arranged at intervals.

[0009] The membrane aeration gas inlet pipe of the plurality of hydrophobic membrane assemblies is communicated with a membrane aeration gas total inlet pipe, and the membrane aeration tail gas discharge pipe of the plurality of hydrophobic membrane assemblies is connected with a membrane aeration tail gas discharge total pipe; and the water production pipe of the plurality of ultra-micro filtration membrane assemblies is communicated with a water production total pipe.

[0010] The distance between the membrane aeration gas inlet pipe of the adjacent hydrophobic membrane assembly and the water production pipe of the ultra-micro filtration membrane assembly is 5-20 cm; preferably, the height of the hydrophobic membrane assembly and the height of the ultra-micro filtration membrane assembly are independently 1-3 m.

[0011] The application also comprises a use method of the anaerobic membrane bioreactor, comprising the following steps:

[0012] Air is sent into the tubular path of the hydrophobic membrane assembly by a fan, preferably, the inlet air pressure is 0.1-0.2 MPa; preferably, the pressure is 0.15 MPa; and low-oxygen air is discharged from the membrane pool through the membrane aeration tail gas pipe;

[0013] Water produced by the ultra-micro filtration membrane assembly at least at one end is pumped out of the membrane pool through the water production pipe by a negative pressure suction pump; preferably, the water production time is 10-30 minutes, preferably 20 minutes; the membrane flux is set to 5-15 L / (m 2 ·h); preferably, the membrane flux is 10 L / (m 2 ·h); the water production is stopped by valve control, the ultra-micro filtration membrane is back-flushed by a back-flushing pump through a back-flushing water pipe; preferably, the back-flushing water amount is 1.2-1.5 times of the water production amount, and the back-flushing time is 60-90 seconds;

[0014] Optionally, the aeration tail gas produced by the membrane aeration tail gas pipe of the hydrophobic membrane assembly is introduced into an air aeration structure through a pipeline for continuous pulse aeration for 40-90 seconds.

[0015] The application also comprises a sewage treatment system comprising the anaerobic membrane bioreactor and an aerobic membrane bioreactor.

[0016] The aerobic membrane bioreactor comprises an aerobic membrane pool, an ultra-micro filtration membrane assembly arranged in the aerobic membrane pool, and an aerobic air aeration structure arranged at the bottom of the aerobic membrane pool; the membrane aeration tail gas discharge pipe of the anaerobic membrane bioreactor is communicated with the aerobic air aeration structure.

[0017] The application also comprises a use method of the sewage treatment system, comprising the following steps: the membrane aeration tail gas discharged from the anaerobic membrane bioreactor is introduced into the aerobic air aeration structure of the aerobic membrane bioreactor through a pipeline in series, so as to control the membrane pollution of the conventional aerobic MBR.

[0018] Preferably, the aerobic air aeration structure is a hollow fiber hydrophobic membrane.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The anaerobic membrane bioreactor of this invention combines solid-liquid separation via ultrafiltration membranes with anaerobic biological treatment, utilizing anaerobic microorganisms to degrade high-concentration, recalcitrant organic matter in wastewater, effectively improving effluent quality and treatment efficiency. The anaerobic membrane bioreactor of this invention produces excellent effluent quality, occupies a small area, maintains a high concentration of anaerobic sludge within the reactor, has low sludge production, and a long sludge age; it operates flexibly and stably, and has strong resistance to shock loads. Attached Figure Description

[0021] Figure 1 This is a simplified structural diagram of an anaerobic membrane bioreactor.

[0022] Figures 2-3 This is a schematic diagram showing the connection between an anaerobic membrane bioreactor and an aerobic membrane bioreactor.

[0023] Figures 4-5 Schematic diagram of the anaerobic reaction corridor. Detailed Implementation

[0024] 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.

[0025] Figure 1 An anaerobic membrane bioreactor is shown, comprising a membrane tank 5, a hydrophobic membrane module 1 disposed within the membrane tank, and an ultrafiltration membrane module 7. The hydrophobic membrane module 1 is connected to a membrane aeration inlet pipe 2 and a membrane aeration exhaust pipe 10. The ultrafiltration membrane module is connected to a permeate pipe, which, as one embodiment, includes a first permeate pipe 3 and a second permeate pipe 8 respectively disposed on both sides of the ultrafiltration membrane module. The ultrafiltration membrane module 7 is connected to a backwash water pipe 4. An air aeration structure 9 is provided at the bottom of the membrane tank 5. The air aeration structure can be a conventional perforated pipe or a pulse aeration box, preferably a pulse aeration box.

[0026] The hydrophobic membrane module and the ultrafiltration membrane module can be independently structured as hollow fiber membranes, flat sheet membranes, or tubular membranes, respectively. Hollow fiber membranes are preferred because their specific surface area is larger than that of flat sheet and tubular membranes, which is beneficial for increasing the biofilm loading capacity formed by bacterial adhesion on the membrane surface.

[0027] For hollow fiber membrane modules and flat sheet membranes, hydrophobic membrane modules 1 and ultrafiltration membrane modules 7 can be arranged alternately in parallel. For tubular membranes, hydrophobic membrane modules 1 and ultrafiltration membrane modules 7 can be arranged in a sleeve-like configuration. Hollow fiber membrane modules can be categorized into curtain-type, cylindrical, and square structures, with curtain-type modules being preferred. The preferred hydrophobic membrane module 1 in the membrane tank is a hollow fiber curtain-type hydrophobic membrane module, and the preferred ultrafiltration membrane module 7 is a hollow fiber ultrafiltration curtain-type membrane module. The preferred arrangement of these two is an alternating parallel arrangement. The height of the hollow fiber ultrafiltration curtain-type membrane module and the hollow fiber curtain-type hydrophobic membrane module is 1–3 m. The center distance between the first product water pipe 3 of each hollow fiber ultrafiltration curtain-type membrane module and the membrane aeration inlet pipe 2 of the hollow fiber curtain-type hydrophobic membrane module is 5–20 cm. The maximum pore size of the hydrophobic membrane in the hollow fiber curtain-type hydrophobic membrane module is 0.10–10 μm.

[0028] The anaerobic membrane bioreactor operates as follows: air is supplied via a blower through the membrane aeration inlet pipe 2 into the tube side of the hydrophobic membrane module 1 (hollow fiber curtain type hydrophobic membrane module). Oxygen is supplied to the biofilm growing on the hydrophobic membrane surface through the hydrophobic membrane pores in a bubble-free aeration manner, creating a good dissolved oxygen gradient along the biofilm thickness direction. This allows nitrification and denitrification reactions to occur simultaneously within the biofilm. This simplifies the process, saves energy, and reduces carbon source requirements, thereby achieving highly efficient simultaneous nitrification and denitrification. Low-oxygen air is discharged from the membrane tank 5 through the membrane aeration tailpipe 10.

[0029] In membrane tank 5, a biofilm grows on the surface of the ultrafiltration membrane module 7 (hydrophilic ultrafiltration membrane) under anaerobic conditions. Through biochemical control, the anaerobic ammonia oxidation process can be achieved. Anaerobic ammonia oxidizing bacteria directly utilize NH4+. 4+ NO2 is an electron donor. - As an electron acceptor, it generates N2. The anaerobic microfiltration membrane module 7 produces water, which is then pumped out of the membrane tank via a negative pressure pump or siphon through the first product water pipe 3 and the second product water pipe 8 at both ends of the ultrafiltration membrane. The water production time is 5–60 minutes. Then, the water production is stopped by a valve, and a backwash pump backwashes the ultrafiltration membrane through the backwash water pipe 4 of the ultrafiltration membrane module. The backwash water volume is 1.2–1.5 times the production water volume, and the backwash time is 30–300 seconds.

[0030] Depending on the quality of the raw water and the product water, air or membrane aeration tail gas can be periodically introduced into the air aeration structure 9 as needed. The thickness of the biofilm growing on the hydrophobic membrane and ultrafiltration membrane surfaces is controlled through aerobic aeration. The process parameters, such as membrane aeration pressure, ultrafiltration membrane permeate flow rate, permeate time, backwash water volume and time, and aerobic aeration volume and time, are all automatically controlled by a program.

[0031] The anaerobic membrane bioreactor of this invention, through precise control of parameters such as bubble-free aeration pressure, temperature, sludge time (SRT), and reflux ratio, can regulate the growth status of biofilms grown on hydrophobic membrane surfaces, biofilms grown on hydrophilic ultrafiltration membrane surfaces, and biological colonies in the water between the membranes. It can achieve highly efficient and stable denitrification under conditions of significant energy saving (bubble-free oxygenation) and no need for organic carbon sources, and significantly reduce sludge production, thereby reducing sludge disposal pressure.

[0032] Depending on the quality of the anaerobic MBR permeate, it can be followed up with conventional aerobic processes or aerobic MBR processes. The membrane aeration tail gas (10g) can be extracted and used in subsequent conventional aerobic processes to fully utilize the remaining oxygen, or used for aeration and cleaning in the aerobic MBR process to control membrane fouling. This reduces the total air consumption of the wastewater treatment system, lowers system operating costs, and improves the final permeate quality.

[0033] Figure 2 The diagram illustrates the connection between an anaerobic membrane bioreactor and conventional aerobic MBR process sections. The membrane aeration tail gas discharged from the anaerobic membrane bioreactor via membrane aeration tail gas pipe 10 is used for aeration and cleaning of the aerobic MBR process section to control membrane fouling. This reduces the total air consumption of the wastewater treatment system and improves the final effluent quality. The aerobic membrane bioreactor used in the aerobic MBR process section includes an aerobic membrane tank 12 and an aerobic ultrafiltration membrane module 14 (which can be the same as the ultrafiltration membrane module 7 of the anaerobic membrane bioreactor) installed within the aerobic membrane tank. The aerobic ultrafiltration membrane module 14 includes a third permeate pipe 11 and a fourth permeate pipe 15. An aerobic air aeration structure 19 is installed at the bottom of the aerobic membrane tank 12. The membrane aeration tail gas discharged from the anaerobic membrane bioreactor via membrane aeration tail gas pipe 10 is connected to the aerobic air aeration structure 19 for aeration. The aerobic air aeration structure 9 can be a conventional perforated pipe or a pulse aeration box, preferably a pulse aeration box. As one form, Figure 3 As shown, the aerobic tank membrane aeration and cleaning structure of the aerobic MBR process section can be a hollow fiber hydrophobic membrane 20, but the maximum pore size of the hollow fiber hydrophobic membrane (0.6 μm) should be greater than the hydrophobic membrane pore size (0.2 μm) of the hydrophobic membrane module in the anaerobic MBR membrane tank.

[0034] Figure 4 An anaerobic reaction chamber is shown, comprising multiple sets of the aforementioned hydrophobic membrane modules (maximum pore size 0.20 μm) and ultrafiltration membrane modules; the hydrophobic membrane modules and ultrafiltration membrane modules are spaced apart, each with a membrane height of 2 m. The membrane aeration inlet pipes 2 of the multiple sets of hydrophobic membrane modules are connected to the membrane aeration main inlet pipe 23, and the membrane aeration exhaust pipes 10 of the multiple sets of hydrophobic membrane modules are connected to the membrane aeration exhaust main pipe 21; the permeate pipes of the multiple sets of ultrafiltration membrane modules are connected to the permeate main pipe 22.

[0035] The anaerobic reaction chamber operation method of this invention is as follows: Air is supplied by a blower through the membrane aeration inlet pipe 2 into the tube side of the parallel hydrophobic membrane module 1 (hollow fiber curtain type hydrophobic membrane module), with the inlet air gauge pressure being 0.15 MPa. The low-oxygen air is discharged from the membrane tank through the membrane aeration exhaust manifold 21. Permeate from both ends of the ultrafiltration membrane module 7 is drawn out of the membrane tank through the permeate manifold 22 using a negative pressure suction pump. The permeate time is 20 minutes, and the membrane flux is set to 10 L / (m²). 2 (h). Then, the water production is stopped by valve control, and the backwash pump backwashes the ultrafiltration membrane module 7 through the backwash water pipe. The backwash water volume is 1.5 times the water production volume, and the backwash time is 60 seconds. The above process parameters, such as water production time, backwash water volume and time, and aeration exhaust gas emission time, are automatically controlled by the program.

[0036] Figure 5 The diagram shows that multiple air aeration structures 9 are installed inside the anaerobic reaction corridor, which are connected by an aeration main pipe 25 to achieve aeration of the anaerobic reaction corridor.

[0037] In summary, the anaerobic membrane bioreactor of this invention combines solid-liquid separation via ultrafiltration membranes with anaerobic biological treatment, utilizing anaerobic microorganisms to degrade high-concentration, recalcitrant organic matter in wastewater, effectively improving effluent quality and treatment efficiency. The anaerobic membrane bioreactor of this invention produces excellent effluent quality, occupies a small area, maintains a high concentration of anaerobic sludge within the reactor, has low sludge production, and a long sludge age; it also operates flexibly and stably, with strong resistance to shock loads.

[0038] 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. An anaerobic membrane bioreactor, characterized in that, It includes a membrane tank, a hydrophobic membrane module disposed in the membrane tank, and a hydrophilic ultrafiltration membrane module; the hydrophobic membrane module is connected to a membrane aeration inlet pipe and a membrane aeration exhaust pipe; the ultrafiltration membrane module is connected to a product water pipe; and the ultrafiltration membrane module is connected to a backwash water pipe.

2. The anaerobic membrane bioreactor according to claim 1, characterized in that, An air aeration structure is provided at the bottom of the membrane tank.

3. The anaerobic membrane bioreactor according to claim 1, characterized in that, The hydrophobic membrane assembly and the ultrafiltration membrane assembly are independently in multiple sets; the hydrophobic membrane assembly and the ultrafiltration membrane assembly are arranged at intervals.

4. The anaerobic membrane bioreactor according to claim 3, characterized in that, The membrane aeration inlet pipes of the multiple sets of hydrophobic membrane modules are connected to the main membrane aeration inlet pipe, and the membrane aeration exhaust pipes of the multiple sets of hydrophobic membrane modules are connected to the main membrane aeration exhaust pipe; the water production pipes of the multiple sets of ultrafiltration membrane modules are connected to the main water production pipe.

5. The anaerobic membrane bioreactor according to claim 3, characterized in that, The distance between the membrane aeration inlet pipe of the adjacent hydrophobic membrane module and the water production pipe of the ultrafiltration membrane module is 5-20cm; preferably, the height of the hydrophobic membrane module and the ultrafiltration membrane module is independently 1-3m.

6. A method of using the anaerobic membrane bioreactor according to any one of claims 1-5, characterized in that, Includes the following steps: Air is supplied to the membrane fiber tube side of the hydrophobic membrane module via a blower through the membrane aeration inlet pipe. Preferably, the inlet air gauge pressure is 0.1-0.2 MPa; more preferably, it is 0.15 MPa. Low-oxygen air is discharged from the membrane tank through the membrane aeration tailpipe. Using a negative pressure suction pump, permeate from at least one end of the ultrafiltration membrane module is drawn out of the membrane tank via a permeate pipe; preferably, the permeate time is 10-30 minutes, more preferably 20 minutes; the membrane flux is set to 5-15 L / (m²). 2 •h); preferably 10L / (m 2 ·h); Water production is stopped by valve control, and the ultrafiltration membrane is backwashed by a backwash pump through a backwash water pipe; preferably, the backwash water volume is 1.2-1.5 times the production water volume, and the backwash time is 60-90 seconds. Optionally, the aeration tail gas generated by the hydrophobic membrane module membrane aeration tail gas pipe can be introduced into the air aeration structure through the pipeline for continuous pulse aeration for 40-90 seconds.

7. A wastewater treatment system, characterized in that, Includes the anaerobic membrane bioreactor and the aerobic membrane bioreactor as described in any one of claims 1-5.

8. The wastewater treatment system according to claim 7, characterized in that, The aerobic membrane bioreactor includes an aerobic membrane tank, an ultrafiltration membrane module disposed within the aerobic membrane tank, and an aerobic air aeration structure disposed at the bottom of the aerobic membrane tank; the membrane aeration exhaust pipe of the anaerobic membrane bioreactor is connected to the aerobic air aeration structure.

9. A method of using the wastewater treatment system according to any one of claims 7-8, characterized in that, The process includes the following steps: the membrane aeration tail gas discharged from the anaerobic membrane bioreactor is introduced into the aerobic air aeration structure in the aerobic membrane bioreactor through pipelines to control membrane fouling in conventional aerobic MBRs.

10. The method of using the wastewater treatment system according to claim 9, characterized in that, The aerobic air aeration structure is a hollow fiber hydrophobic membrane.

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