A closed sewage biochemical treatment device and process

Abstract

The present invention discloses a closed sewage biochemical treatment device, which includes a closed tank body; an inner ring is arranged therein, and a flow guiding umbrella is arranged on the lower side of the inner ring; there is a gap between the bottom of the inner ring and the flow guiding umbrella, and there is a gap between the flow guiding umbrella and the inner wall of the tank body; in the upper side area of the flow guiding umbrella, an aerobic zone, an anoxic / anaerobic zone are respectively formed between the inner side of the inner ring, the outer side of the inner ring and the closed tank body, and a sedimentation zone is formed in the lower side area of the flow guiding umbrella; a deep water and shallow aeration unit is arranged in the aerobic zone, and a sludge reflux unit is also arranged; a hydraulic cyclone unit is arranged in the sedimentation zone, which cooperates with the sludge discharge port at the bottom of the tank body to discharge sludge; the sewage inlet on the tank body is communicated with the aerobic zone and / or the anoxic zone; the top end of the flow guiding umbrella is communicated with the purified water outlet for clarifying the treated water. The present invention also provides a corresponding closed sewage biochemical treatment process. The device and the process are environmentally friendly and safe, realizing the full biochemical process cycle of anoxia, anaerobic and aerobic, and can improve the biochemical efficiency and the sewage treatment effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and relates to a closed sewage biochemical treatment device and process. Background Art

[0002] Aerobic biochemical treatment is a basic method for sewage treatment: Usually, sewage, inoculated microbial sludge, and air are introduced into a biochemical pool. Under appropriate temperature and oxygen content, microorganisms grow and reproduce, degrading and consuming organic matter. The basic process is as Figure 1 shown, where: A is an anoxic and anaerobic zone for hydrolysis and denitrification. It can be placed at the front end, or at the back end, or both the front and back ends are provided; there may be fillers in the pool for microorganisms to attach, and a stirrer is provided to promote uniform mass transfer in the reaction; O is an aerobic biochemical pool, often referred to as an aerobic zone or an aeration zone, usually an open shallow pool system for the convenience of aeration; an aeration device is built-in, and an external blower supplies air; the secondary sedimentation tank clarifies the mixed liquid in the biochemical pool, and the effluent is discharged after advanced treatment or directly discharged; part of the sedimented sludge is discharged externally through a sludge return pump, and part is returned to the aeration tank.

[0003] Problems existing are: 1. The hydraulic retention time in the biochemical pool is very long. Generally, domestic sewage requires several hours, and industrial sewage requires several days, resulting in a huge floor area; the secondary sedimentation tank is a shallow pool structure, and the floor area is also relatively large; 2. The large pool surface leads to the overflow of waste gas and serious non-point source air pollution; 3. The large pool surface leads to short-circuit of water flow, uneven mass transfer, rapid overflow of aeration, short contact time of gas, liquid, and solid (microorganisms), and low oxygenation and biochemical efficiency; 4. The large pool surface results in large heat dissipation and is not conducive to heat preservation, especially in cold regions, causing the biochemical process to stagnate; 5. The layout of each treatment unit is a planar superposition, and the space is not fully utilized.

[0004] Chinese patent document CN102583736B discloses an activated sludge and biofilm composite circulating flow sewage biochemical treatment process and device. Its biochemical pool includes an anoxic zone, an anaerobic zone, and an activated sludge and biofilm collaborative treatment zone. A circulating water flow is formed through pusher aeration in the activated sludge and biofilm collaborative treatment zone to achieve pump-free internal circulation, which has great improvement compared with the traditional technology. However, the self-circulation of this technical solution only exists in the activated sludge and biofilm collaborative treatment zone, and the circulation of the entire biochemical process is not achieved; moreover, the entire biochemical pool is still a traditional open pool body, and there is a problem of unorganized emission of VOCs waste gas. Summary of the Invention

[0005] Aiming at the problems in the above-mentioned prior art, the purpose of the present invention is to provide a closed-type closed sewage biochemical treatment device and process with anoxic, anaerobic, and aerobic full biochemical process circulation. The device and process are environmentally friendly and safe, realizing the full biochemical process circulation of anoxia, anaerobic, and aerobic, and can improve the biochemical efficiency and the sewage treatment effect.

[0006] One of the objectives of the present invention is to provide a closed sewage biochemical treatment device, and the technical solution adopted is as follows:

[0007] A closed sewage biochemical treatment device includes a closed tank body; an inner ring is arranged inside the tank body, and a flow guiding umbrella is arranged below the inner ring; there is a gap in the vertical direction between the bottom of the inner ring and the flow guiding umbrella, and there is a gap in the horizontal direction between the flow guiding umbrella and the inner wall of the tank body;

[0008] In the upper side area of the flow guiding umbrella, two zones are formed between the inner side of the inner ring, the outer side of the inner ring and the closed tank body, namely an aerobic zone and an anoxic / anaerobic zone, and the lower side area of the flow guiding umbrella forms a sedimentation zone; the anoxic / anaerobic zone includes an upper anoxic zone and a lower anaerobic zone, and the water in the anoxic zone flows to the anaerobic zone under the action of gravity;

[0009] A deep water shallow aeration unit is arranged in the aerobic zone, the deep water shallow aeration unit is communicated with the anaerobic zone and is also communicated with the gas source outside the tank body, and is used to form a pressure difference to make the sewage in the anaerobic zone flow back to the aerobic zone, so that the sewage flows back between the anoxic zone, the anaerobic zone and the aerobic zone;

[0010] A sludge return unit is also arranged in the aerobic zone, the sludge return unit is communicated with the sedimentation zone and is also communicated with the gas source outside the tank body, and is used to extract the sludge in the sedimentation zone and return it to the aerobic zone and aerate to activate the sludge;

[0011] A hydraulic cyclone unit is arranged in the sedimentation zone, and the hydraulic cyclone unit cooperates with the sludge discharge port at the bottom of the tank body to discharge the sludge;

[0012] A sewage inlet and a purified water outlet are arranged on the tank body, and the sewage inlet is communicated with the aerobic zone or the anoxic zone; the top of the flow guiding umbrella is communicated with the purified water outlet, and is used to discharge the clarified treated water below the umbrella surface of the flow guiding umbrella and above the hydraulic cyclone unit.

[0013] Preferably, the deep water shallow aeration unit includes an aeration lift pipe and a strong pipe aerator integrally connected in the aerobic zone, the aeration lift pipe is arranged vertically above the flow guiding umbrella and is communicated with the anaerobic zone, and the strong pipe aerator is connected to the gas source outside the tank body in the horizontal plane, and under the action of the pressure difference formed by aerating the aerobic zone, the sewage circulates between the anoxic zone, the anaerobic zone and the aerobic zone.

[0014] Preferably, the sludge return unit includes an aeration lift pipe and a strong pipe aerator integrally arranged, one end of the aeration lift pipe is located in the sedimentation zone and the other end is located in the aerobic zone, the strong pipe aerator is connected to the gas source outside the tank body, and under the action of the pressure difference formed by aerating the aerobic zone, the sludge in the sedimentation zone flows back to the aerobic zone.

[0015] Preferably, the hydrocyclone unit includes a push-flow pump arranged outside the tank body, a water suction annular pipe arranged close to the inner wall of the bottom of the tank body, and a water spraying annular pipe arranged close to the middle of the bottom of the tank body; the water suction annular pipe is connected to the inlet end of the push-flow pump, and the water spraying annular pipe is connected to the outlet end of the push-flow pump; nozzle tips are respectively arranged on the water suction annular pipe and the water spraying annular pipe for forming circumferential water flow.

[0016] The sludge discharge port is arranged at the center of the bottom of the tank body, opposite to the center of the circumferential water flow.

[0017] Further, the nozzle inclination angles on the water suction annular pipe and the water spraying annular pipe are the same.

[0018] Further, the bottom of the tank body is set as an inverted cone, and the sludge discharge port is arranged at the bottom of the cone.

[0019] Preferably, a catalyst bed layer is arranged inside the umbrella surface on the lower side of the flow guiding umbrella, and an ozone inlet pipe is further arranged on the lower side of the catalyst bed layer for forming an ozone catalytic oxidation reaction area inside the umbrella surface on the lower side of the flow guiding umbrella.

[0020] Further, a biochar purification unit is internally arranged at the top of the flow guiding umbrella, and the biochar purification unit is communicated with the top of the flow guiding umbrella for adsorbing the sewage after ozone catalytic oxidation treatment; and the purified water outlet is communicated with the outlet of the biochar purification unit.

[0021] Preferably, fixed or floating fillers or catalysts are arranged in the aerobic zone, anoxic zone and anaerobic zone.

[0022] Preferably, an exhaust port is arranged at the top of the tank body.

[0023] Preferably, the gas-water ratio of the deep water and shallow aeration unit is controlled to be (3 - 10):1.

[0024] Preferably, the reflux ratio of the anoxic and anaerobic mixed sewage in the anaerobic zone is controlled to be (5 - 25):1.

[0025] Preferably, the gas-water ratio of the sludge reflux unit is controlled to be (1.5 - 4):1.

[0026] Preferably, the reflux ratio of the sludge in the sedimentation zone is controlled to be (0.5 - 3):1.

[0027] The second object of the present invention is to provide a closed sewage biochemical treatment process, including the following steps:

[0028] The original sewage is introduced into the anoxic zone or aerobic zone above the flow guiding umbrella in the closed tank body. Under the aeration of the deep water and shallow aeration unit, the air content in the water of the aerobic zone increases and the density decreases, creating a pressure difference between the aerobic zone and the anoxic zone and anaerobic zone, causing the sewage to form a three-dimensional circulating flow. The anoxic sewage in the anoxic zone flows downward under the action of gravity, with the dissolved oxygen decreasing, and becomes an anaerobic zone at the lower part of the anoxic and anaerobic zone for anaerobic biochemical treatment. The anaerobic sewage in the anaerobic zone flows back into the aerobic zone for aeration to carry out anoxic-anaerobic-aerobic biochemical treatment of the sewage;

[0029] The sewage after anoxic-anaerobic-aerobic biochemical treatment settles under the action of gravity and enters the sedimentation area below the flow guiding umbrella in the closed tank body for sedimentation and clarification. The clarified and purified water obtained at the top of the flow guiding umbrella is discharged from the purified water outlet; the solid-containing part in the sewage is deposited at the lower part of the sedimentation area to form sludge. Part of the sludge is pumped back to the aerobic zone by the sludge reflux unit to extract part of the sludge in the sedimentation area, fully dissolve air into it to activate the sludge, and carry out aerobic biochemical treatment of the sewage in the aerobic zone; the other part of the sludge is pushed to move centripetally under the action of the circumferential water flow formed by the hydraulic cyclone unit, and the sludge is discharged from the sludge discharge port at the center of the bottom of the tank body.

[0030] Preferably, the solid-containing sewage after biochemical treatment settles under the action of gravity and enters the sedimentation area:

[0031] The clarified water accumulates under the umbrella surface of the flow guiding umbrella at the upper part of the sedimentation area. Ozone enters the catalyst bed layer arranged under the flow guiding umbrella in the tank. Under the swirling push of the hydraulic cyclone unit, it slowly diffuses and moves under the umbrella, fully contacts with the clarified water, and carries out ozone catalytic oxidation treatment;

[0032] A biochar purification unit is built in at the top of the flow guiding umbrella. A small amount of ring-opening and chain-breaking small molecule organic pollutants and ozone oxidation tail gas generated after ozone catalytic oxidation enter the biochar purification unit under closed conditions for further deep purification treatment; the purified water flows out of the biochar purification unit to the purified water outlet.

[0033] The present invention can bring the following beneficial effects:

[0034] 1) The closed sewage biochemical treatment device of the present invention divides the anaerobic and anoxic zone, aerobic zone, and sedimentation zone by arranging an inner ring and a flow guiding umbrella in a closed tank body. Among them, there is a gap in the vertical direction between the bottom of the inner ring and the end of the flow guiding umbrella, so that the anaerobic zone and the aerobic zone communicate above the flow guiding umbrella. There is a gap in the horizontal direction between the end of the flow guiding umbrella and the inner wall of the tank body, so that the anoxic and anaerobic zone or the aerobic zone communicates with the sedimentation zone vertically. Thus, although the anoxic zone, anaerobic zone, and aerobic zone are functionally independent partitions, they are integrally connected. By aerating in the aerobic zone, the density of the aerobic zone can be reduced to form a three-dimensional circulating flow in the closed tank body. Therefore, the device of the present invention realizes a closed anoxic, anaerobic, and aerobic full biochemical process cycle through deep water and shallow aeration, with gas-carrying circulation, making the water flow state in the tank stable, and the gas, liquid, and solid contact sufficient, significantly improving the biochemical treatment efficiency. Moreover, it greatly reduces the floor area, increases the depth of the biochemical tank, and superimposes the sedimentation tank in the lower part of the space, with the floor area less than 1 / 4 of the existing process.

[0035] 2) In the device and process of the present invention, the raw sewage is introduced into the anoxic zone or aerobic zone in the closed tank body, and the deep water and shallow aeration unit is used to fully dissolve air into the sewage, so that the oxygen content in the aerobic zone reaches the required level. Under the action of aeration, a self-adaptive three-dimensional circulating flow is formed in the anoxic zone, anaerobic zone, and aerobic zone in the tank body, so that the sewage in the anoxic zone flows down to the anaerobic zone, and the anaerobic sewage flows back to the aerobic zone for aeration, realizing the anoxic-anaerobic-aerobic biochemical treatment of the sewage. The sewage in the tank enters the sedimentation zone after biochemical treatment under anoxic, anaerobic, and aeration conditions, settles in the sedimentation zone under the flow guiding umbrella, and the clarified purified water obtained at the top of the flow guiding umbrella is discharged from the purified water outlet. At the same time, the solid sludge sinks under the action of gravity, and part of the sludge deposited at the lower part of the sedimentation zone is pumped to the aerobic zone through the sludge reflux unit, fully dissolving air to activate the sludge and performing aerobic biochemical treatment on the sewage in the aerobic zone. The sludge deposited at the bottom of the tank body is discharged from the sludge discharge port through the hydrocyclone unit. Thus, the biochemical treatment of the sewage is completed in the closed tank body, making the biochemical process uniform, stable, lasting, and efficient.

[0036] 3) In the present invention, the positions of the aerobic zone and the anoxic and anaerobic zone can be arbitrarily swapped. The sewage inlet can be connected with a pipeline to introduce the raw sewage into any position of the anoxic zone and / or aerobic zone. By forming a self-adaptive three-dimensional circulating flow in the anoxic zone, anaerobic zone, and aerobic zone, an alternating circulating extended biochemical system such as anoxic-anaerobic-aeration, aeration-anoxic-anaerobic, anoxic-anaerobic-aeration can be formed in the tank body, making the treatment liquid reflux sufficient, and the biochemical process uniform, stable, lasting, and thus more efficient, and capable of adapting to the needs of different water quality treatments.

[0037] 4) The present invention can also integrate advanced oxidation for in-depth treatment in a closed tank body, and perform ozone catalytic oxidation treatment through a catalyst bed layer arranged inside the umbrella; the sewage after ozone catalytic oxidation treatment enters the biochar purification unit for further adsorption, in-depth biochemical treatment, and further in-depth oxidation treatment, realizing three-stage sewage treatment capacity, effectively ensuring the impurity removal rate of the purified water discharged. At the same time, it does not increase the floor area of the device and saves costs.

[0038] 5) The present invention uses a closed tank body for biochemical treatment of sewage, which can eliminate non-point source waste gas pollution, be more environmentally friendly and safe, and reduce investment and save operating costs. In addition, the present invention does not require the setting of a sewage lift pump, nor the laying of a large number of aeration devices (aeration heads) and system pipelines, and does not require a large amount of civil engineering, with good economy and being suitable for popularization and application. Brief Description of the Drawings

[0039] Figure 1 It is a schematic flow diagram of a traditional biochemical treatment process in the prior art.

[0040] Figure 2 It is a schematic structural diagram of the closed sewage biochemical treatment device of the present invention.

[0041] The meanings of the reference symbols in the drawings are as follows:

[0042] 1 - tank body, 10 - sludge discharge port, 11 - sewage inlet, 12 - purified water outlet; 13 / 14 / 15 / 16 / 17 - opening, 18 - exhaust port;

[0043] 2 - inner ring; 3 - diversion umbrella, 30 - ozone inlet pipe, 31 - biochar purification unit;

[0044] 4 - deep water and shallow aeration unit, 40 - aeration lift pipe, 41 - strong pipe aeration pipe;

[0045] 5 - sludge return unit, 50 - aeration lift pipe, 51 - strong pipe aeration pipe;

[0046] 6 - hydrocyclone unit, 60 - push flow pump, 61 - suction ring pipe, 62 - spray ring pipe;

[0047] O - aerobic zone / aeration zone; A - anoxic and anaerobic zone; S - sedimentation zone.

[0048] H - biochemical tank, H1 - agitator, H2 - aeration device, H3 - blower;

[0049] L - secondary sedimentation tank, L1 - sludge return pump. Detailed Embodiments

[0050] The technical solutions in the present invention will be clearly and completely described below in conjunction with specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0051] According to an embodiment provided by the present invention, as Figure 2 shown, it is a closed sewage biochemical treatment device, including a closed tank body 1; an inner ring 2 is arranged in the tank body 1, and a flow guiding umbrella 3 is arranged below the inner ring 2; there is a gap in the vertical direction between the bottom of the inner ring 2 and the flow guiding umbrella 3, and there is a gap in the horizontal direction between the flow guiding umbrella 3 and the inner wall of the tank body 1;

[0052] In the upper side area of the flow guiding umbrella 3, two partitions are formed between the inner side of the inner ring 2, the outer side of the inner ring 2 and the tank body 1, namely an aerobic zone O and an anoxic / anaerobic zone A, and a sedimentation zone S is formed in the lower side area of the flow guiding umbrella 3; the anoxic / anaerobic zone A includes an upper anoxic zone and a lower anaerobic zone, and the water in the anoxic zone flows to the anaerobic zone under the action of gravity;

[0053] A deep water and shallow aeration unit 4 is arranged in the aerobic zone O, and the deep water and shallow aeration unit 4 is communicated with the anaerobic zone and also communicated with a gas source outside the tank body 1, and is used for aeration to form a pressure difference to make the sewage in the anaerobic zone flow back to the aerobic zone O;

[0054] A sludge return unit 5 is also arranged in the aerobic zone O, and the sludge return unit 5 is communicated with the sedimentation zone S and also communicated with a gas source outside the tank body 1, and is used for pumping the sludge in the sedimentation zone S back to the aerobic zone and aerating to activate the sludge;

[0055] A hydraulic cyclone unit 6 is arranged in the sedimentation zone S, and the hydraulic cyclone unit 6 cooperates with a sludge discharge port 10 at the bottom of the tank body 1 to discharge the sludge;

[0056] A sewage inlet 11 and a purified water outlet 12 are arranged on the tank body 1, and the sewage inlet 11 is communicated with the aerobic zone O or the anoxic zone; the top of the flow guiding umbrella 3 is communicated with the purified water outlet 12, and is used for discharging the clarified treated water below the umbrella surface of the flow guiding umbrella 3 and above the hydraulic cyclone unit 5.

[0057] In this embodiment, an inner ring 2 and a flow guiding umbrella 3 are arranged in a closed tank body 1 to divide the anoxic-anaerobic zone A, the aerobic zone (or called the aeration zone O), and the sedimentation zone S. Among them, in the anoxic-anaerobic zone A, according to the up-down relationship in the space, the upper part is the anoxic zone. The anoxic sewage in the anoxic zone flows downward under the action of gravity, and at the same time, the dissolved oxygen decreases as it goes down, and it becomes an anaerobic zone at the lower part of the anoxic-anaerobic zone; there is a gap in the vertical direction between the bottom of the inner ring 2 and the end of the flow guiding umbrella 3, so that the anaerobic zone is communicated with the aerobic zone O above the flow guiding umbrella 3, and there is a gap in the horizontal direction between the end of the flow guiding umbrella 3 and the inner wall of the tank body 1, so that the anoxic-anaerobic zone A or the aerobic zone O is communicated with the sedimentation zone S up and down. Thus, although the anoxic-anaerobic zone A, the aerobic zone O, and the sedimentation zone S are functionally independent partitions, they are integrally communicated. By introducing the original sewage into the anoxic zone and / or the aerobic zone O in the closed tank body 1, the deep water shallow aeration unit 4 is used to fully dissolve air into the sewage, so that the oxygen content in the aerobic zone O reaches the required level. Under the action of aeration, the air content in the water of the aerobic zone O increases and the density decreases, creating a pressure difference between the aerobic zone O and the anaerobic zone A, combined with Figure 2 as shown by the arrow located above the flow guiding umbrella in the figure, a self-adaptive three-dimensional circulating flow of the anoxic zone, anaerobic zone, and aerobic zone O in the tank body 1 is formed, so that the sewage in the anaerobic zone is pumped to the aerobic zone O for aeration, realizing the anoxic-anaerobic-aerobic biochemical treatment of the sewage; the sewage in the tank body 1 enters the sedimentation zone S after biochemical treatment under anoxic, anaerobic, and aeration conditions, settles in the sedimentation zone S under the flow guiding umbrella 3, and the clarified purified water obtained at the top of the flow guiding umbrella 3 is discharged from the purified water outlet 12; at the same time, the solid sludge sinks under the action of gravity, and part of the sludge deposited at the lower part of the sedimentation zone S is pumped back to the aerobic zone O through the sludge reflux unit 5, fully dissolving air to activate the sludge and performing aerobic biochemical treatment on the sewage in the aerobic zone O; the sludge deposited at the bottom of the tank body 1 is discharged from the sludge discharge port through the hydrocyclone unit 6. Thus, the biochemical treatment of the sewage is completed in the closed tank body 1, making the biochemical process uniform, stable, lasting, and efficient.

[0058] In addition, the positions of the aerobic zone O and the anoxic-anaerobic zone A can be arbitrarily swapped. The sewage inlet 10 therein can be connected to a pipeline to introduce the original sewage into any position of the anoxic zone and / or the aerobic zone O, forming an anoxic-anaerobic-aerobic, aerobic-anoxic-anaerobic, anoxic-anaerobic-aerobic-anoxic-anaerobic and other alternating circulating extended biochemical systems through the self-adaptive three-dimensional circulating flow of the anoxic zone, anaerobic zone, and aerobic zone in the tank body 1, so that the treatment liquid reflux is sufficient, making the biochemical process uniform, stable, and lasting, thus being more efficient and capable of adapting to the needs of different water quality treatments.

[0059] According to another embodiment provided by the present invention, as Figure 2As shown, it is a closed sewage biochemical treatment device. In this embodiment, on the basis of Embodiment 1, as a preferred embodiment, the deep water and shallow aeration unit 4 includes an aeration and lift pipe 40 and a strong pipe aerator 41 integrally connected in the aerobic zone O. The aeration and lift pipe 40 is arranged above the flow guide umbrella 3 and is connected to the aerobic zone O and the anaerobic zone. The strong pipe aerator 41 is connected to the gas source outside the tank body 1, and under the pressure difference formed by aerating the aerobic zone O, the sewage in the anaerobic zone is returned to the aerobic zone O.

[0060] In this embodiment, an external gas source is introduced through the strong pipe aerator 41 in the deep water and shallow aeration unit 4, so that the gas enters the aeration and lift pipe 40 and overflows in the aerobic zone O to aerate the aerobic zone O, increasing the air content in the water and reducing the density, thereby forming a pressure difference between the anaerobic zone and the aerobic zone O to promote the three-dimensional circular flow of the anoxic zone, anaerobic zone and aerobic zone O. Moreover, the oxygen content in the aerobic zone O reaches the required level, so as to fully carry out biochemical treatment on the sewage. Among them, the strong pipe aerator 41 is communicated with the external gas source through the opening 13 on the tank body 1. Preferably, the aeration and lift pipe 40 is arranged vertically, and the strong pipe aerator 41 is connected to the gas source outside the tank body 1 in the horizontal plane.

[0061] As another preferred embodiment, the sludge return unit 5 includes an aeration and lift pipe 50 and a strong pipe aerator 51 integrally arranged. One end of the aeration and lift pipe 50 is located in the sedimentation zone S and the other end is located in the aerobic zone O. The strong pipe aerator 51 is connected to the gas source outside the tank body 1, and under the pressure difference formed by aerating the aerobic zone O, the sludge in the sedimentation zone S is returned to the aerobic zone O.

[0062] In this embodiment, an external gas source is introduced through the strong pipe aerator in the sludge return unit 5, so that the gas enters the aeration and lift pipe 50 and overflows in the aerobic zone O to aerate the aerobic zone O; at the same time, due to the pressure difference formed by the reduction of density in the aeration and lift pipe 50, the sludge in the sedimentation zone S is extracted, and the air is fully dissolved through aeration, and the sludge is released in the aerobic zone O after activation, thereby increasing the sludge concentration of biochemical treatment and improving the biochemical treatment efficiency. Among them, the strong pipe aerator 51 is communicated with the external gas source through the opening 14 on the tank body 1. Preferably, the aeration and lift pipe 50 is arranged vertically.

[0063] As another preferred embodiment, the hydrocyclone unit 6 includes a flow-pushing pump 60 provided outside the tank body 1, a water suction annular pipe 61 disposed near the inner wall of the bottom of the tank body 1, and a water spraying annular pipe 62 disposed near the middle of the bottom of the tank body 1; the water suction annular pipe 61 is connected to the inlet end of the flow-pushing pump 60, and the water spraying annular pipe 62 is connected to the outlet end of the flow-pushing pump 60; nozzle tips are respectively arranged on the water suction annular pipe 61 and the water spraying annular pipe 62 for forming circumferential water flow; and the sludge discharge port 10 is disposed at the center of the bottom of the tank body 1, opposite to the center of the circumferential water flow.

[0064] In this embodiment, a hydrocyclone unit 6 is arranged in the sedimentation zone S. As shown by the arrow located below the flow guiding umbrella in Figure 2 By starting the flow-pushing pump 60, the flow-pushing pump 60 is communicated with the water suction annular pipe 61 through a liquid inlet pipeline, and sewage at the bottom of the sedimentation zone S is sucked through the nozzle tips on the water suction annular pipe 61; then the sucked sewage is communicated with the water spraying annular pipe 62 through the liquid outlet pipeline of the flow-pushing pump 60 and is sprayed through the nozzle tips on the water spraying annular pipe 62, so as to promote the formation of a stable circumferential water flow, push the sludge to move towards the center, and thus be discharged through the sludge discharge port 10 at the center of the bottom of the tank body 1.

[0065] More preferably, the nozzle inclination angles on the water suction annular pipe 61 and the water spraying annular pipe 62 are the same. In this embodiment, the water suction annular pipe 61 and the water spraying annular pipe 62 are both provided with nozzle tips having the same inclination angle, which promotes the formation of a circumferential water flow under the action of the flow-pushing pump 60 and drives the pool water to stably swirl. In practical applications, the tank body 1 is provided with openings 15 and 16 connected to the liquid inlet and outlet pipelines of the flow-pushing pump 60. More preferably, the bottom of the tank body 1 is set as an inverted cone, and the sludge discharge port 10 is disposed at the cone bottom. Thus, it is convenient to promote the sludge to move towards the cone bottom under the action of the circumferential water flow, and then be discharged through the sludge discharge port 10 at the cone bottom.

[0066] As another preferred embodiment, a catalyst bed layer (not shown in the figure) is arranged inside the umbrella surface below the flow guiding umbrella 3, and an ozone inlet pipe 30 is further arranged below the catalyst bed layer for forming an ozone catalytic oxidation reaction zone inside the umbrella surface below the flow guiding umbrella 1.

[0067] In this embodiment, the clarified water is collected by the flow guiding umbrella 3, and ozone is supplied from the outside. Specifically, ozone enters the tank below the flow guiding umbrella 3 through the tank opening 17, and slowly diffuses and moves below the flow guiding umbrella 3 under the swirling push of the hydrocyclone unit 6. Due to the arrangement of the umbrella surface, there is no overflow space for ozone, that is, ozone cannot overflow below the umbrella surface, so that ozone is fully contacted with the clarified water, realizing the deep catalytic oxidation function of the clarified sewage after sedimentation separation in the sedimentation zone S.

[0068] Preferably, a biochar purification unit 31 is built into the top of the flow guiding umbrella 3. The biochar purification unit 31 is communicated with the top of the flow guiding umbrella 3 and is used for adsorbing and treating the sewage after ozone catalytic oxidation. And the purified water outlet 12 is communicated with the outlet of the biochar purification unit 31. Among them, the biochar purification unit 31 is a cylinder body built with biochar.

[0069] In this embodiment, a biochar purification unit 31 can be built into the top of the flow guiding umbrella 3 (under the umbrella surface). The sewage after ozone catalytic oxidation is adsorbed and treated here. A small amount of ring-opening and chain-breaking small molecule organic pollutants and ozone oxidation tail gas generated after ozone catalytic oxidation enter the built-in biochar purification unit 31 under closed conditions for further deep purification treatment.

[0070] As another preferred embodiment, fixed or floating fillers are arranged in the aerobic zone O, the anoxic zone and the anaerobic zone, so as to further improve and strengthen the reaction efficiency. Preferably, floating fillers are selected, and spoke-type fluidized fillers made of PE material or porous granular fluidized fillers made of polyurethane material can be selected. Further preferably, the specific surface area of the spoke-type fluidized filler is 500-800m 2 / m 3 , and the specific surface area of the polyurethane porous granular fluidized filler is 1500-3500m 2 / m 3 .

[0071] As another preferred embodiment, an exhaust port 18 is arranged at the top of the tank body 1. Thus, the waste gas is collected through this exhaust port 18 and sent to the outside for waste gas treatment.

[0072] According to an embodiment provided by the present invention, as shown in Figure 2 , a closed sewage biochemical treatment process includes the following steps:

[0073] Introduce the raw sewage into the anoxic zone and / or aerobic zone O above the flow guiding umbrella 3 in the closed tank body 1. Under the aeration action of the deep water and shallow aeration unit 4, the air content in the water of the aerobic zone O increases and the density decreases, causing a pressure difference between the aerobic zone O and the anaerobic zone, resulting in a three-dimensional circulating flow. The sewage in the anoxic zone flows into the anaerobic zone under the action of gravity, and the sewage in the anaerobic zone flows back into the aerobic zone O for aeration to perform anoxic-anaerobic-aerobic biochemical treatment on the sewage;

[0074] The sewage after anoxic-anaerobic-aerobic biochemical treatment settles under the action of gravity and enters the sedimentation area S under the side of the diversion umbrella in the closed tank body for sedimentation and clarification. The clarified and purified water obtained at the top of the diversion umbrella is discharged from the purified water outlet; the solid-containing part in the sewage is deposited at the lower part of the sedimentation area S to form sludge. Part of the sludge is pumped by the sludge reflux unit 5 to reflux part of the sludge in the sedimentation area S to the aerobic area O, fully dissolved with air to activate the sludge, and perform aerobic biochemical treatment on the sewage in the aerobic area O; the other part of the sludge is pushed by the circumferential water flow formed by the hydrocyclone unit 6 to move centripetally, and the sludge is discharged from the sludge discharge port 10 at the center of the bottom of the tank body 1.

[0075] In this embodiment, by introducing the original sewage into the anoxic area and / or the aerobic area O in the closed tank body 1, and using the deep water shallow aeration unit 4 to fully dissolve air into the sewage, the oxygen content in the aerobic area O reaches the required level. Under the action of aeration, the air content in the water of the aerobic area O increases and the density decreases, creating a pressure difference between the aerobic area O and the anaerobic area, forming an adaptive three-dimensional circular flow of the anoxic area, anaerobic area and aerobic area in the tank body 1. The sewage in the anoxic area flows into the anaerobic area under the action of gravity, and the sewage in the anaerobic area is refluxed into the aerobic area O for aeration to perform anoxic-anaerobic-aerobic biochemical treatment on the sewage; the solid-containing sewage in the tank body 1 enters the sedimentation area S after biochemical treatment under anoxic-anaerobic and aeration conditions, and settles in the sedimentation area S under the diversion umbrella 3. The clarified and purified water obtained at the top of the diversion umbrella 3 is discharged from the purified water outlet 12; at the same time, the solid sludge sinks under the action of gravity, and part of the sludge deposited at the lower part of the sedimentation area S is pumped by the sludge reflux unit 5 to reflux to the aerobic area, fully dissolved with air to activate the sludge, and simultaneously perform aerobic biochemical treatment on the sewage in the aerobic area O; the sludge deposited at the bottom of the tank body 1 is discharged from the sludge discharge port 10 through the hydrocyclone unit 6. Thus, the biochemical treatment of the sewage is completed in the closed tank body 1, making the biochemical process uniform, stable, lasting and efficient.

[0076] As a preferred embodiment, the solid-containing sewage after biochemical treatment settles under the action of gravity and enters the sedimentation area S:

[0077] The clarified water accumulates under the umbrella surface of the diversion umbrella 3 at the upper part of the sedimentation area S. Ozone enters the catalyst bed layer arranged under the diversion umbrella 3 in the tank from the ozone inlet pipe 3. Under the swirling push of the hydrocyclone unit 6, it slowly diffuses and moves under the umbrella, fully contacts with the clarified water, and performs ozone catalytic oxidation deep treatment.

[0078] A biochar purification unit 31 is provided at the top of the diversion umbrella 3. The sewage treated by ozone catalytic oxidation enters the biochar purification unit 31 for adsorption treatment. A small amount of ring-opening and chain-breaking small-molecule organic pollutants and ozone oxidation tail gas generated after ozone catalytic oxidation enter the built-in or external biochar purification unit 31 under closed conditions for further deep purification treatment; the purified water flows out of the biochar purification unit 31 to the purified water outlet 12.

[0079] In this embodiment, the diversion umbrella 3 at the upper part of the sedimentation area S is used to gather the clarified water, and deep purification treatment is carried out by ozone catalytic oxidation with the catalyst arranged in the umbrella; the sewage treated by ozone catalytic oxidation enters the biochar purification unit 31 for further adsorption treatment and further deep purification treatment, effectively ensuring the impurity removal rate of the discharged purified water.

[0080] As another preferred embodiment, the air-water ratio of the deep water and shallow aeration unit 4 is controlled to be (3-10):1; the reflux ratio of the anoxic and anaerobic mixed sewage in the anaerobic area is controlled to be (5-25):1. Among them, the reflux ratio of the anoxic and anaerobic mixed sewage refers to the ratio of the reflux volume of the anoxic and anaerobic mixed sewage to the sewage inflow volume of the tank body.

[0081] As another preferred embodiment, the speed of the three-dimensional cyclic flow is controlled at 0.3-0.95 m / s.

[0082] As another preferred embodiment, the air-water ratio of the sludge reflux unit 5 is controlled to be (1.5-4):1, and the reflux ratio of the sludge in the sedimentation area S is controlled to be (0.5-3):1. Among them, the reflux ratio of the sludge is the ratio of the reflux volume of the sludge to the sewage inflow volume of the tank body.

[0083] Using the above embodiments, the sewage is subjected to biochemical treatment to form the following application examples:

[0084] Comparative Example 1

[0085] Raw materials: Flow rate 100 m 3 / day, indicators: COD 1500 mg / L, BOD 700 mg / L, ammonia nitrogen 65 mg / L, total nitrogen 80 mg / L.

[0086] Using traditional devices and processes: A / O biochemical tank + air flotation + ozone catalytic oxidation

[0087] Floor area of the device: 1200 m 2 , The unorganized emission of VOCs waste gas is about 1000 m 3 / day.

[0088] Effluent after treatment: COD 50 mg / L, ammonia nitrogen 15 mg / L, total nitrogen 30 mg / L.

[0089] Application Example 1

[0090] The raw materials are the same as those in Comparative Example 1.

[0091] The closed biochemical sewage treatment process of the present invention is adopted:

[0092] The raw sewage is introduced into the anoxic zone or aerobic zone O above the diversion umbrella 3 in the closed tank body 1. Under the aeration of the deep water and shallow aeration unit 4, the air content in the water of the aerobic zone O increases and the density decreases, creating a pressure difference between the aerobic zone O and the anaerobic zone, causing a three-dimensional circular flow. The sewage in the anoxic zone flows into the anaerobic zone under the action of gravity, and the sewage in the anaerobic zone flows back into the aerobic zone O for aeration to carry out anoxic-anaerobic-aerobic biochemical treatment of the sewage;

[0093] The sewage after anoxic-anaerobic-aerobic biochemical treatment settles under the action of gravity and enters the sedimentation area S below the diversion umbrella 3 in the closed tank body 1 for sedimentation and clarification:

[0094] The clarified water accumulates under the umbrella surface of the diversion umbrella 3 at the upper part of the sedimentation area S. Ozone enters the catalyst bed layer arranged below the diversion umbrella 3 in the tank from the ozone inlet pipe 3. Under the swirling push of the hydraulic swirling unit 6, it slowly diffuses and moves under the umbrella, fully contacting the clarified water for ozone catalytic oxidation treatment; A biochar purification unit 31 is arranged at the top of the diversion umbrella 3. A small amount of ring-opening and chain-breaking small molecule organic pollutants and ozone oxidation tail gas generated after ozone catalytic oxidation enter the built-in or external biochar purification unit 31 under closed conditions for further deep purification treatment; The purified water flows out from the biochar purification unit 31 to the purified water outlet 12;

[0095] The solid-containing part in the sewage is deposited at the lower part of the sedimentation area S to form sludge. Part of the sludge is pumped by the sludge return unit 5 to draw part of the sludge in the sedimentation area S back to the aerobic zone O, fully dissolving air to activate the sludge and carrying out aerobic biochemical treatment of the sewage in the aerobic zone O; Another part of the sludge is pushed by the circumferential water flow formed by the hydraulic swirling unit 6 to move centripetally, and the sludge is discharged from the sludge discharge port 10 at the center of the bottom of the tank body 1.

[0096] Among them, the aeration air-water ratio of the deep water and shallow aeration unit 4 is controlled at 4:1, the reflux ratio of anoxic and anaerobic sewage is 15:1, the three-dimensional circular flow velocity is 0.4 m / s, and the liquid hourly space velocity of ozone catalytic oxidation is 4 h -1 , the air-water ratio of the sludge return unit is 3:1, and the reflux ratio of the sludge is 2.5:1.

[0097] Floor area of the device: 260 m 2 , and the unorganized emission amount of VOCs waste gas is 0.

[0098] The effluent after treatment: COD is less than 35 mg / L, ammonia nitrogen is 5 mg / L, and total nitrogen is 15 mg / L.

[0099] Application Example 2

[0100] The raw materials are the same as those in Comparative Example 1.

[0101] The closed biochemical sewage treatment process of the present invention is adopted: the same as that in Application Example 1. The only difference is that:

[0102] Among them, the aeration air-water ratio of the deep water and shallow aeration unit 4 is controlled at 5:1, the anoxic and anaerobic sewage reflux ratio is 18:1, the circulation flow rate is 0.5 m / s, and the liquid hourly space velocity of ozone catalysis is 4 h -1 , and the air-water ratio of the sludge reflux unit is 3:1, and the reflux ratio of the sludge is 2:1.

[0103] Plant floor area: 260 m 2 , and the unorganized emission amount of VOCs waste gas is 0.

[0104] The treated effluent: COD 30 mg / L, ammonia nitrogen 5 mg / L, total nitrogen less than 12 mg / L.

[0105] Application Example 3

[0106] The raw materials are the same as those in Comparative Example 1.

[0107] The closed biochemical sewage treatment process of the present invention is adopted: the same as that in Application Example 1. The only difference is that:

[0108] Among them, the aeration air-water ratio of the deep water and shallow aeration unit 4 is controlled at 6:1, the anoxic and anaerobic sewage reflux ratio is 18:1, the circulation flow rate is 0.6 m / s, and the liquid hourly space velocity of ozone catalytic oxidation is 4 h -1 , and the air-water ratio of the sludge reflux unit is 3:1, and the reflux ratio of the sludge is 3:1.

[0109] Plant floor area: 260 m 2 , and the unorganized emission amount of VOCs waste gas is 0.

[0110] The treated effluent: COD 26 mg / L, ammonia nitrogen 3 mg / L, total nitrogen less than 7 mg / L.

[0111] Comparative Example 2

[0112] Raw materials: flow rate 150 m 3 / day, indicators: COD 1000 mg / L, BOD5 50 mg / L, ammonia nitrogen 60 mg / L, total nitrogen 70 mg / L.

[0113] Adopt the traditional process: A / O biochemical pool + secondary sedimentation tank + high-efficiency air flotation tank + ozone catalytic oxidation tank device

[0114] Floor area: 1200 m 2 , and the unorganized emission amount of VOCs waste gas is about 1200 m3 / day.

[0115] Treated effluent: COD: 45 mg / L, ammonia nitrogen: 13 mg / L, total nitrogen: 25 mg / L.

[0116] Application Example 4

[0117] The raw materials are the same as those in Comparative Example 2.

[0118] The closed biochemical sewage treatment process of the present invention is adopted: the same as in Application Example 1. The only difference is that:

[0119] Among them, the aeration gas-water ratio of the deep water and shallow aeration unit 4 is controlled at 4:1, the reflux ratio of anoxic and anaerobic sewage is 20:1, the circulation flow rate is 0.3 m / s, and the liquid hourly space velocity of ozone catalytic oxidation is 4 h -1 , and the gas-water ratio of the sludge return unit is 3:1, and the sludge reflux ratio is 2.5:1.

[0120] Plant floor area: 260 m 2 , and the unorganized emission of VOCs waste gas is 0.

[0121] Treated effluent: COD 27 mg / L, ammonia nitrogen 5 mg / L, total nitrogen 9 mg / L.

[0122] Application Example 5

[0123] The raw materials are the same as those in Comparative Example 2.

[0124] The closed biochemical sewage treatment process of the present invention is adopted: the same as in Application Example 1. The only difference is that:

[0125] Among them, the aeration gas-water ratio of the deep water and shallow aeration unit 4 is controlled at 9:1, the reflux ratio of anoxic and anaerobic sewage is 10:1, the three-dimensional circulation flow rate is 0.8 m / s, and the liquid hourly space velocity of ozone catalytic oxidation is 4 h -1 , and the gas-water ratio of the sludge return unit is 3:1, and the sludge reflux ratio is 3:1.

[0126] Plant floor area: 260 m 2 , and the unorganized emission of VOCs waste gas is 0.

[0127] Treated effluent: COD 25 mg / L, ammonia nitrogen 4.2 mg / L, total nitrogen 8.1 mg / L.

[0128] Application Example 6

[0129] The raw materials are the same as those in Comparative Example 2.

[0130] The closed biochemical sewage treatment process of the present invention is adopted: the same as in Application Example 1. The only difference is that:

[0131] Among them, the aeration air-water ratio of the deep water and shallow aeration unit 4 is 7:1, the reflux ratio of anoxic and anaerobic sewage is 15:1, the circulation flow rate is 0.6 m / s, and the liquid hourly space velocity of ozone catalytic oxidation is 4 h -1 , the air-water ratio of the sludge reflux unit is 3:1, and the reflux ratio of the sludge is 3:1.

[0132] Plant floor area: 260 m 2 , and the unorganized emission of VOCs waste gas is 0.

[0133] The treated effluent: COD 29 mg / L, ammonia nitrogen 3.8 mg / L, total nitrogen 10 mg / L.

[0134] It should be noted that the above embodiments can be freely combined according to needs. The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A closed sewage biochemical treatment device, characterized in that: it includes a closed tank body; an inner ring is arranged inside the tank body, and a flow guiding umbrella is arranged on the lower side of the inner ring; there is a gap in the vertical direction between the bottom of the inner ring and the flow guiding umbrella, and there is a gap in the horizontal direction between the flow guiding umbrella and the inner wall of the tank body; in the upper side area of the flow guiding umbrella, two partitions are formed between the inner side of the inner ring, the outer side of the inner ring and the closed tank body, namely an aerobic zone and an anoxic / anaerobic zone, and the lower side area of the flow guiding umbrella forms a sedimentation zone; the anoxic / anaerobic zone includes an upper anoxic zone and a lower anaerobic zone, and the water in the anoxic zone flows to the anaerobic zone under the action of gravity; a deep water and shallow aeration unit is arranged in the aerobic zone, the deep water and shallow aeration unit is communicated with the anaerobic zone and is also communicated with the gas source outside the tank body, and is used to form a pressure difference to make the sewage in the anaerobic zone flow back to the aerobic zone; a sludge return unit is also arranged in the aerobic zone, the sludge return unit includes an integrally arranged aeration lift pipe and a strong pipeline aeration pipe, one end of the aeration lift pipe is located in the sedimentation zone and the other end is located in the aerobic zone, and the strong pipeline aeration pipe is connected to the gas source outside the tank body, and by aerating the aerobic zone, the sludge in the sedimentation zone flows back to the aerobic zone under the action of pressure difference; a hydraulic cyclone unit is arranged in the sedimentation zone, and the hydraulic cyclone unit cooperates with the sludge discharge port at the bottom of the tank body to discharge sludge; the tank body is provided with a sewage inlet and a purified water outlet, and the sewage inlet is communicated with the aerobic zone and / or the anoxic zone; the top end of the flow guiding umbrella is communicated with the purified water outlet, and is used to discharge the clarified treated water below the umbrella surface of the flow guiding umbrella and above the hydraulic cyclone unit; a catalyst bed layer is arranged in the umbrella surface on the lower side of the flow guiding umbrella, and an ozone inlet pipe is also arranged on the lower side of the catalyst bed layer, and is used to form an ozone catalytic oxidation reaction zone in the umbrella surface on the lower side of the flow guiding umbrella.

2. The closed sewage biochemical treatment device according to claim 1, characterized in that: the deep water and shallow aeration unit includes an aeration lift pipe and a strong pipeline aeration pipe integrally connected in the aerobic zone, the aeration lift pipe is arranged vertically on the upper side of the flow guiding umbrella and is communicated with the anaerobic zone, and the strong pipeline aeration pipe is connected to the gas source outside the tank body in the horizontal plane, and under the action of the pressure difference formed by aerating the aerobic zone, the sewage circulates among the anoxic zone, the anaerobic zone and the aerobic zone.

3. The closed sewage biochemical treatment device according to claim 1, characterized in that: the hydraulic cyclone unit includes a push flow pump arranged outside the tank body, a water absorption ring pipe arranged close to the inner wall at the bottom of the tank body, and a water spraying ring pipe arranged close to the middle at the bottom of the tank body; the water absorption ring pipe is connected to the inlet end of the push flow pump, and the water spraying ring pipe is connected to the outlet end of the push flow pump; nozzles are respectively arranged on the water absorption ring pipe and the water spraying ring pipe, and are used to form a circumferential water flow; the sludge discharge port is arranged at the center of the bottom of the tank body and is opposite to the center of the circumferential water flow.

4. The closed sewage biochemical treatment device according to claim 3, characterized in that: the nozzle inclination angles on the water absorption ring pipe and the water spraying ring pipe are the same; and / or; the bottom of the tank body is set as an inverted cone shape, and the sludge discharge port is arranged at the cone bottom.

5. The closed sewage biochemical treatment device according to claim 1, It is characterized in that: A biochar purification unit is built inside the top of the said flow guiding umbrella, and the biochar purification unit is communicated with the top of the flow guiding umbrella for further treating the sewage after ozone catalytic oxidation treatment; And the purified water outlet is communicated with the outlet of the biochar purification unit.

6. The closed sewage biochemical treatment device according to claim 1, It is characterized in that: Fixed or floating fillers or catalysts are arranged in the said aerobic zone, anoxic zone and anaerobic zone; and / or, An exhaust port is arranged at the top of the tank body.

7. A closed sewage biochemical treatment process, It is characterized in that, The closed sewage biochemical treatment device according to any one of claims 1-6 is adopted, and it includes the following steps: Introduce the raw sewage into the anoxic zone or aerobic zone above the flow guiding umbrella in the closed tank body. Under the aeration action of the deep water and shallow aeration unit, the air content in the water of the aerobic zone increases and the density decreases, causing a pressure difference between the aerobic zone, anoxic zone and anaerobic zone, so that the sewage forms a three-dimensional circulating flow. The anoxic sewage in the anoxic zone flows into the anaerobic zone, and the anaerobic zone sewage flows back into the aerobic zone for aeration to carry out anoxic-anaerobic-aerobic biochemical treatment of the sewage; The sewage after anoxic-anaerobic-aerobic biochemical treatment settles under the action of gravity and enters the sedimentation area below the flow guiding umbrella in the closed tank body for sedimentation and clarification. The clarified purified water obtained at the top of the flow guiding umbrella is discharged from the purified water outlet; the solid-containing part in the sewage is deposited at the lower part of the sedimentation area to form sludge. Part of the sludge is pumped back to the aerobic zone by the sludge reflux unit to extract part of the sludge in the sedimentation area, fully dissolve air, activate the sludge, and carry out aerobic biochemical treatment of the sewage in the aerobic zone; Another part of the sludge is pushed to move centripetally under the action of the circumferential water flow formed by the hydraulic cyclone unit, so that the sludge is discharged from the sludge discharge port at the center of the bottom of the tank body; The solid-containing sewage after biochemical treatment settles under the action of gravity and enters the sedimentation area. The clarified water gathers under the umbrella surface of the flow guiding umbrella at the upper part of the sedimentation area. Ozone enters the catalyst bed layer arranged under the flow guiding umbrella in the tank. Under the swirling push of the hydraulic cyclone unit, it slowly diffuses and moves under the umbrella and makes full contact with the clarified water for ozone catalytic oxidation treatment.

8. The closed sewage biochemical treatment process according to claim 7, It is characterized in that, A biochar purification unit is built inside the top of the flow guiding umbrella. A small amount of ring-opening and chain-breaking small molecule organic pollutants and ozone oxidation tail gas generated after ozone catalytic oxidation enter the biochar purification unit under closed conditions for further deep purification treatment; the purified water flows out of the biochar purification unit to the purified water outlet.

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