Distributed sewage treatment equipment capable of switching working modes

Abstract

The utility model discloses distributed sewage treatment equipment capable of switching working modes, which comprises a water inlet pipe, the water inlet pipe is communicated with a multi-stage biological treatment tank, the multi-stage biological treatment tank is communicated with a sedimentation tank, an effluent weir of the sedimentation tank is communicated with a clean water tank, the sedimentation tank is communicated with an MBR (Membrane Bioreactor) membrane tank through a middle communication passage, and the MBR membrane tank is communicated with a water inlet pipe. And the MBR membrane tank is communicated with the clean water tank through an MBR water producing pump. The device has the beneficial effects that different working modes of independent water production of the sedimentation tank, independent water production of the MBR membrane tank and mixed water production of the sedimentation tank and the MBR membrane tank can be switched by controlling the start-stop state of the MBR system through the height of the liquid level. And the impact resistance of the distributed sewage treatment equipment to the water quantity is improved, and scenes with different effluent quality requirements can be met.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewage treatment, and in particular relates to distributed sewage treatment equipment with switchable working modes. Background Art

[0002] Distributed sewage treatment devices are widely used in rural sewage treatment. Rural sewage has the characteristic of large fluctuations in water volume. During special periods such as holidays, the water volume will suddenly increase. This puts high demands on the impact resistance of distributed sewage treatment equipment. In recent years, the MBR process has received extensive attention and application in the field of rural domestic sewage treatment due to its advantages such as short residence time, small footprint, and good effluent quality. However, the MBR membrane has an upper limit on water production during operation, and it is easy to overflow in a large area due to untimely treatment when the water volume suddenly increases.

[0003] At present, the MBR process has an upper limit on water production and cannot effectively solve the problem of large fluctuations in rural sewage volume. Some researchers have proposed "a sedimentation tank for a dual-system membrane bioreactor" (Chinese patent CN210001733U), which organically integrates the MBR membrane and the sedimentation tank to achieve the function of switching the effluent of the MBR membrane or the sedimentation tank. Other researchers have proposed "dual-system fully automatic integrated sewage treatment equipment" (Chinese patent CN213037624U), which uses the "A / O+sedimentation tank+MBR" process to achieve the switching of two sets of mud and water separation devices, AO+sedimentation tank or AO+MBR. And "a dual-mode composite dynamic membrane rural domestic sewage treatment device" (Chinese patent CN114314839A), which can realize the switching of DMBR membrane effluent and anaerobic effluent, and can meet the different drainage requirements of rural areas during irrigation and non-irrigation periods. Similar patents include (Chinese patent CN116332348A) and so on. The essence of the above patents is to protect the operation of the MBR membrane through the sedimentation tank, and most of them use switching valves to switch the working mode. They do not fundamentally solve the problem of the upper limit of the water production of the MBR process.

[0004] In addition, "A rural domestic sewage treatment device with switchable processes" (Chinese patent CN219907336U) can realize the switch between the "anaerobic + anoxic + aerobic + sedimentation" system and the "aerobic + sedimentation" system. It can meet the different needs of farmland irrigation and standard discharge. However, the technology proposed in this patent does not have an MBR membrane system, so the water quality of the produced water cannot meet more stringent discharge standards.

[0005] At the same time, in the process of rural sewage treatment, relevant requirements and standards have become increasingly stringent in controlling the total nitrogen content in effluent. At present, most distributed domestic sewage treatment devices use nitrification liquid reflux in the AO process or AAO process, or add a denitrification filter at the effluent end to achieve the purpose of removing total nitrogen, which places high demands on control and operation personnel.

[0006] Therefore, it is necessary to develop a distributed domestic sewage treatment equipment that can achieve good total nitrogen removal, meet the needs of large water volume fluctuations and high impact load resistance. Utility Model Content

[0007] The purpose of the utility model is to provide a distributed sewage treatment equipment with switchable working modes, which solves the problems of small water volume and large fluctuation range of water volume in rural domestic sewage, especially during special periods such as holidays, when the water volume will suddenly increase; the use of a single MBR membrane technology has the problem of water production upper limit, which is easy to cause sewage overflow; at the same time, the total nitrogen content in the effluent is required to be higher and higher, and the traditional nitrification liquid reflux requires the nitrification liquid reflux pump to be turned on for a long time, which consumes a lot of electricity.

[0008] In view of the shortcomings of the existing technology, the utility model proposes a method that does not require a nitrification liquid reflux pump, a sludge reflux pump and multiple water inlet points to achieve the function of good removal of total nitrogen. It adopts a distributed domestic sewage treatment device that can switch the water outlet mode through a sedimentation tank or MBR to adapt to rural sewage treatment scenarios with large water volume fluctuations and high denitrification requirements.

[0009] The purpose of the utility model is achieved through the following technical solutions:

[0010] A distributed sewage treatment equipment with switchable working modes comprises an inlet pipe, the inlet pipe is connected to a multi-stage biological treatment tank, the multi-stage biological treatment tank is connected to a sedimentation tank, the outlet weir of the sedimentation tank is connected to a clean water tank, the sedimentation tank is connected to an MBR membrane tank through an intermediate connecting passage, and the MBR membrane tank is connected to the clean water tank through an MBR water production pump.

[0011] Furthermore, the multi-stage biological treatment tank includes a first anoxic tank, a first aerobic tank, a second anoxic tank and a second aerobic tank which are connected in sequence, the water inlet pipe is connected to the first anoxic tank, and the second aerobic tank is connected to the sedimentation tank.

[0012] Furthermore, the effective volume ratio of the first anoxic pool, the first aerobic pool, the second anoxic pool and the second aerobic pool is 1:3:1:1.

[0013] Furthermore, the water inlet flow ratio between the first anoxic pool and the second anoxic pool is (3-5):1.

[0014] Furthermore, the water inlet pipe is also connected to the second anoxic tank.

[0015] Furthermore, the clean water tank is connected to the water outlet pipe, the sedimentation tank is connected to the mud discharge pipe, and the mud discharge pipe is provided with a mud discharge valve.

[0016] Furthermore, a sedimentation tank gas stripping device is provided in the sedimentation tank, and an MBR tank gas stripping device is provided in the MBR membrane tank. The sludge return ends of the sedimentation tank gas stripping device and the MBR tank gas stripping device are both connected to the head end tank of the multi-stage biological treatment tank, and the aeration fan supplies air to the sedimentation tank gas stripping device and the MBR tank gas stripping device through a reflux control valve.

[0017] Furthermore, a liquid level meter is provided in the MBR membrane pool, and an MBR fan supplies air to the MBR membrane pool.

[0018] Furthermore, it also includes an aeration fan, which supplies air to the aeration device of the multi-stage biological treatment tank, and an anoxic stirring valve is arranged on the air supply pipeline of the anoxic tank in the multi-stage biological treatment tank.

[0019] Furthermore, the clean water tank is connected to the MBR membrane tank through an MBR backwash pump.

[0020] Beneficial effects of the utility model:

[0021] 1. By controlling the start and stop status of the MBR system through the liquid level height, the different working modes of independent water production in the sedimentation tank, independent water production in the MBR membrane tank, and mixed water production in the sedimentation tank and MBR membrane tank can be switched. This improves the impact resistance of distributed sewage treatment equipment to water volume and the ability to cope with different effluent water quality requirements.

[0022] 2. The AOAO biochemical system with multiple water inlet points can achieve good removal of total nitrogen without nitrification liquid reflux.

[0023] 3. The air lift device is used to complete the sludge return, reducing the sludge return pump. The first anoxic tank and the second anoxic tank use intermittent aeration and stirring, reducing the cost of stirring equipment and power consumption. In the independent water production mode of the sedimentation tank, only the aeration fan is working in the device, and the energy consumption and failure rate can be reduced.

[0024] The aforementioned main scheme of the utility model and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and protected by the utility model; and in the utility model, (non-conflicting options) options and other options can also be freely combined. After understanding this scheme, those skilled in the art can understand that there are many combinations based on the existing technology and common knowledge, all of which are technical schemes to be protected by the utility model, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the utility model.

[0026] In the figure: 1-water inlet pipe, 2-first anoxic tank, 3-first aerobic tank, 4-second anoxic tank, 5-second aerobic tank, 6-sedimentation tank, 7-clear water tank, 8-MBR membrane tank, 9-water outlet pipe, 10-sludge discharge pipe, 11-sludge discharge valve, 12-middle connecting passage, 13-sedimentation tank air stripping device, 14-MBR tank air stripping device, 15-liquid level meter, 16-aeration fan, 17-first anoxic stirring valve, 18-second anoxic stirring valve, 19-reflux control valve, 20-MBR fan, 21-MBR water production pump, 22-MBR backwash pump. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with specific embodiments and drawings.

[0028] Example

[0029] refer to Figure 1 As shown, a distributed sewage treatment equipment with switchable working modes includes an inlet pipe 1, a multi-stage biological treatment tank (a first anoxic tank 2, a first aerobic tank 3, a second anoxic tank 4 and a second aerobic tank 5), a sedimentation tank 6, a clean water tank 7, an MBR membrane tank 8, an outlet pipe 9, a sludge discharge pipe 10, a sludge discharge valve 11, an intermediate connecting passage 12, a sedimentation tank air stripping device 13, an MBR air stripping device 14, a liquid level meter 15, an aeration fan 16, a first anoxic stirring valve 17, a second anoxic stirring valve 18, a reflux control valve 19, an MBR fan 20, an MBR water production pump 21 and an MBR backwash pump 22.

[0030] The water inlet pipe 1 is connected to the multi-stage biological treatment tank, and the multi-stage biological treatment tank is connected to the sedimentation tank 6, so as to realize the multi-stage biological purification treatment of sewage, that is, the single or combined treatment mode of anoxic, aerobic and anaerobic. The multi-stage biological treatment tank includes a first anoxic tank 2, a first aerobic tank 3, a second anoxic tank 4 and a second aerobic tank 5 which are connected in sequence. The water inlet pipe 1 is connected to the first anoxic tank 2, and the second aerobic tank 5 is connected to the sedimentation tank 6.

[0031] The effective volume ratio of the first anoxic pool 2, the first aerobic pool 3, the second anoxic pool 4 and the second aerobic pool 5 is 1:3:1:1. The water inlet pipe 1 is connected to the first anoxic pool 2 through the main pipe, and is also connected to the second anoxic pool 4 through the branch pipe. When water is inlet, the water inlet flow ratio of the first anoxic pool 2 and the second anoxic pool 4 is adjusted to (3-5):1 through a manual valve.

[0032] The effluent weir of the sedimentation tank 6 is connected to the clean water tank 7 to achieve the overflow of clean water from the sedimentation tank. The sedimentation tank 6 is connected to the MBR membrane tank 8 through the intermediate connecting passage 12, and the MBR membrane tank 8 is connected to the clean water tank 7 through the MBR water production pump 21 to achieve switching to the MBR sewage treatment mode, and the clean water of the MBR membrane tank 8 also flows into the clean water tank 7.

[0033] The clean water tank 7 is connected with the outlet pipe 9 to discharge the clean water from the clean water tank. The sedimentation tank 6 is connected with the mud discharge pipe 10, and the mud discharge pipe 10 is provided with a mud discharge valve 11 to discharge the mud from the sedimentation tank.

[0034] A sedimentation tank stripping device 13 is provided in the sedimentation tank 6, and an MBR tank stripping device 14 is provided in the MBR membrane tank 8. The sludge return ends of the sedimentation tank stripping device 13 and the MBR tank stripping device 14 are both connected to the head end tank of the multi-stage biological treatment tank (i.e., the first anoxic tank 2). The aeration fan 16 supplies air to the sedimentation tank stripping device 13 and the MBR tank stripping device 14 through the reflux control valve 19. The reflux control valve 19 is intermittently opened by the PLC controller to achieve intermittent reflux of the sludge.

[0035] The MBR membrane pool 8 is provided with a liquid level meter 15, through which the liquid level in the pool is identified. The MBR fan 20 supplies air to the MBR membrane pool 8, realizing independent air supply to the MBR pool. The clean water pool 7 is connected to the MBR membrane pool 8 through the MBR backwash pump 22, and backwashing is realized by using clean water.

[0036] The aeration fan 16 supplies air to the aeration device of the multi-stage biological treatment tank (the first anoxic tank 2, the first aerobic tank 3, the second anoxic tank 4 and the second aerobic tank 5), and an anoxic stirring valve is provided on the air supply pipeline of the anoxic tank (the first anoxic tank 2 and the second anoxic tank 4) in the multi-stage biological treatment tank to achieve intermittent stirring.

[0037] The workflow of this utility model:

[0038] Sewage treatment process: Raw water enters the first anoxic tank 2 from the water inlet pipe 1, and is treated in turn through the first aerobic tank 3, the second anoxic tank 4, the second aerobic tank 5 and the sedimentation tank 6. At the same time, the branch of the water inlet pipe 1 can directly introduce part of the raw water into the second anoxic tank 4. After the mixed liquid of the above-mentioned reaction process passes through the mud and water separation of the sedimentation tank 6, an outlet weir is set on the surface of the sedimentation tank, and the supernatant flows into the clear water tank 7 through the outlet weir of the sedimentation tank. It can also reach the MBR membrane tank 8 through the intermediate connecting passage 12 (pipe or port) in the middle of the sedimentation tank, realize the mud and water separation in the MBR membrane tank, and under the action of the MBR water production pump 21, the clear liquid reaches the clear water tank 7. Finally, it overflows to the discharge port through the outlet pipe 9.

[0039] Aeration workflow: After the aeration fan 16 is started, it can simultaneously provide compressed air to the first anoxic tank 2, the first aerobic tank 3, the second anoxic tank 4, the second aerobic tank 5, the sedimentation tank gas stripping device 13, and the MBR tank gas stripping device 14. Among them, the first anoxic tank 2 and the second anoxic tank 4 are respectively equipped with a first anoxic stirring valve 17 and a second anoxic stirring valve 18 on the air supply pipeline. The main pipes of the sedimentation tank gas stripping device 13 and the MBR tank gas stripping device 14 are respectively installed with a reflux control valve 19, which is controlled by the switch of the PLC system. The MBR fan 20 independently supplies air to the MBR membrane tank 8.

[0040] Sludge discharge workflow: A sludge discharge valve 11 is installed on the sludge discharge pipe 10. When the residual sludge accumulates to a certain extent, the sludge discharge is completed by controlling the sludge discharge valve through PLC.

[0041] Sedimentation tank independent water production working mode: turn off the equipment of the MBR mud-water separation system (MBR fan 20, MBR water production pump 21, MBR backwash pump 22), the liquid level of the sedimentation tank 6 rises naturally, and the supernatant reaches the clean water tank 7 through the upper water outlet weir of the sedimentation tank. Finally, it overflows to the discharge port through the outlet pipe 9.

[0042] MBR membrane pool independent water production working mode: start the MBR mud-water separation system, identify the liquid level of the MBR membrane pool 8 through the liquid level meter 15, control the liquid level below the sedimentation tank outlet weir level, and all sewage reaches the clear water tank 7 through the intermediate connecting passage 12 and the MBR membrane pool 8. Finally, it overflows to the discharge port through the outlet pipe 9.

[0043] Sedimentation tank and MBR membrane tank mixed water production working mode: the liquid level of the MBR membrane tank 8 is identified by the liquid level meter 15, the MBR mud-water separation system is started, and the liquid level is controlled above the liquid level of the sedimentation tank outlet weir. The sewage can reach the clear water tank 7 through the sedimentation tank 6, the intermediate connecting passage 12, and the MBR membrane tank 8, and can also reach the clear water tank 7 directly through the sedimentation tank 6. Finally, it overflows to the discharge port through the outlet pipe 9.

[0044] Generally, the effective volume ratio of the first anoxic pool 2, the first aerobic pool 3, the second anoxic pool 4 and the second aerobic pool 5 is 1:3:1:1; when water is inletted, the water flow rate ratio of the first anoxic pool 2 and the second anoxic pool 4 is adjusted by a manual valve to be (3-5):1.

[0045] The first anoxic stirring valve 17 and the second anoxic stirring valve 18 adopt solenoid valves or electric valves, which are opened for 10-30 seconds every 5 minutes to complete the stirring of the first anoxic tank 2 and the second anoxic tank 4. The reflux control valve 19 adopts a solenoid valve or an electric valve, which is opened for 1-2 minutes every 10-20 minutes to return the sludge to the first anoxic tank 2. In order to achieve better denitrification and phosphorus removal effects, the carbon source can be added to the second anoxic tank 4, and the phosphorus removal agent can be added to the second aerobic tank 5.

[0046] Implementation Cases

[0047] like Figure 1 As shown, Example 1 of the utility model is applied to the treatment of domestic sewage in a certain place.

[0048] Designed water flow rate 10m 3 / d. The effective volumes of the first anoxic pool 2, the first aerobic pool 3, the second anoxic pool 4 and the second aerobic pool 5 are: 0.84m 3 , 2.52m3 , 0.84m 3 , 0.84m3. The sedimentation tank adopts an inclined tube sedimentation tank with a designed surface load of 0.74m 3 / ㎡ / h. The effective volume of MBR membrane pool 8 is 1.44m 3 . Add a dephosphorization agent dosing device and add it to the second aerobic tank 5.

[0049] The operating parameters were set as follows: the water flow ratio between the first anoxic tank 2 and the second anoxic tank 4 was 3.5:1;

[0050] The first anoxic stirring valve 17 and the second anoxic stirring valve 18 are opened for 18 seconds every 5 minutes; and the reflux control valve 19 is opened for 1 minute every 10 minutes.

[0051] The MBR fan 20, MBR water production pump 21, and MBR backwash pump 22 only work in the MBR membrane pool independent water production working mode and the sedimentation tank and MBR membrane pool mixed water production working mode. The parameters are as follows: the MBR fan 20 works for 8 minutes and stops for 2 minutes; the MBR water production pump 21 works for 8 minutes and stops for 2 minutes; the MBR backwash pump 22 starts for 3 minutes every 12 hours.

[0052] The results are as follows:

[0053] The seven-day average water flow is 10.5m 3 / d, the sedimentation tank is used in an independent water production mode, the water produced meets the GB18918 Class B standard, and the energy consumption per ton of water is 0.46kWh / m 3 The MBR membrane pool adopts independent water production working mode, and the water production meets the GB18918 Class A standard, with an energy consumption of 1.12kWh / m 3 .

[0054] The seven-day average water flow is 14.3m 3 / d, the sedimentation tank is used in an independent water production mode, the water produced meets the GB18918 Class B standard, and the energy consumption per ton of water is 0.40kWh / m 3 .

[0055] The seven-day average water flow is 22.5m 3 / d, the mixed water production mode of sedimentation tank and MBR membrane tank is adopted, and the water production meets the GB18918 Class B standard, and the energy consumption per ton of water is 0.91kWh / m 3 .

[0056] The overall water quality and energy consumption are at the leading level in the industry.

[0057] The above basic examples and further optional examples of the utility model can be freely combined to form multiple embodiments, which are all embodiments that can be adopted and claimed for protection by the utility model. In the scheme of the utility model, each optional example can be arbitrarily combined with any other basic examples and optional examples.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A distributed sewage treatment device with switchable working modes, comprising a water inlet pipe (1), characterized in that: The water inlet pipe (1) is connected to the multi-stage biological treatment tank, the multi-stage biological treatment tank is connected to the sedimentation tank (6), the water outlet weir of the sedimentation tank (6) is connected to the clean water tank (7), the sedimentation tank (6) is connected to the MBR membrane tank (8) through the intermediate connecting passage (12), and the MBR membrane tank (8) is connected to the clean water tank (7) through the MBR water production pump (21).

2. The distributed sewage treatment equipment with switchable working modes according to claim 1 is characterized in that: The multi-stage biological treatment tank comprises a first anoxic tank (2), a first aerobic tank (3), a second anoxic tank (4) and a second aerobic tank (5) which are connected in sequence, the water inlet pipe (1) is connected to the first anoxic tank (2), and the second aerobic tank (5) is connected to the sedimentation tank (6).

3. The distributed sewage treatment equipment with switchable working modes according to claim 2 is characterized in that: The effective volume ratio of the first anoxic pool (2), the first aerobic pool (3), the second anoxic pool (4) and the second aerobic pool (5) is 1:3:1:

1.

4. The distributed sewage treatment equipment with switchable working modes according to claim 2 or 3, characterized in that: The ratio of water inlet flow rate of the first anoxic pool (2) and the second anoxic pool (4) is (3-5):

1.

5. The distributed sewage treatment equipment with switchable working modes according to claim 2 is characterized in that: The water inlet pipe (1) is also connected to the second anoxic tank (4).

6. The distributed sewage treatment equipment with switchable working modes according to claim 1 is characterized in that: The clean water tank (7) is connected to the water outlet pipe (9), the sedimentation tank (6) is connected to the mud discharge pipe (10), and the mud discharge pipe (10) is provided with a mud discharge valve (11).

7. The distributed sewage treatment equipment with switchable working modes according to claim 1 is characterized in that: The sedimentation tank (6) is provided with a sedimentation tank gas stripping device (13), and the MBR tank gas stripping device (14) is provided in the MBR membrane tank (8). The sludge return ends of the sedimentation tank gas stripping device (13) and the MBR tank gas stripping device (14) are both connected to the head end tank of the multi-stage biological treatment tank, and the aeration fan (16) supplies air to the sedimentation tank gas stripping device (13) and the MBR tank gas stripping device (14) through a return control valve (19).

8. The distributed sewage treatment equipment with switchable working modes according to claim 1 is characterized in that: A liquid level meter (15) is provided in the MBR membrane pool (8), and an MBR fan (20) supplies air to the MBR membrane pool (8).

9. The distributed sewage treatment equipment with switchable working modes according to claim 1 or 7, characterized in that: It also includes an aeration fan (16) which supplies air to an aeration device of the multi-stage biological treatment pool. An anoxic stirring valve is provided on the air supply pipeline of the anoxic pool in the multi-stage biological treatment pool.

10. The distributed sewage treatment equipment with switchable working modes according to claim 1 or 8, characterized in that: The clean water tank (7) is connected to the MBR membrane tank (8) via the MBR backwash pump (22).

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