Hydraulic agitation-based bubbleless oxygen supply biological wastewater treatment apparatus and method

Abstract

The application provides a bubble-free oxygen supply biological sewage treatment equipment based on hydraulic agitation, comprising a biological reactor, a hollow fiber membrane assembly and a mixer, wherein the biological reactor is internally provided with a reaction zone and a gas storage cavity arranged at the middle part above the reaction zone, sludge settlement zones are arranged from bottom to top in the biological reactor outside the reaction zone and the gas storage cavity, a sludge-water separation module and a clear liquid zone are arranged in the biological reactor outside the reaction zone and the gas storage cavity, a clear liquid outlet is arranged on the side wall of the clear liquid zone, the clear liquid outlet is connected to a water collecting device and a water inlet of the hollow fiber membrane assembly, part of the clear liquid is sent to the mixer after being oxygenated by the hollow fiber membrane assembly, water inlets of the mixer are respectively connected to water outlets of the hollow fiber membrane assembly and a sewage source, a water outlet of the mixer is connected to a liquid inlet end of a self-suction type hydraulic agitator, and the mixed sewage enters the reaction zone through the self-suction type hydraulic agitator. The sewage treatment equipment has high oxygen dissolving efficiency, good treatment effect, small land occupation and low energy consumption.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to a bubble-free oxygen supply biological sewage treatment equipment and method based on hydraulic stirring. BACKGROUND

[0002] With the development of modern social productivity, the progress of science and technology, and the adjustment of industrial structure, the society gradually changes from traditional agriculture to industry and service industry, the industrialization level gradually improves, the scale continuously expands, the urban population also becomes more and more, and the amount of domestic sewage and industrial sewage also increases sharply. The domestic sewage contains non-toxic inorganic salts, nitrogen, phosphorus, sulfur and many pathogenic bacteria; the industrial sewage has complex composition, contains various toxic and harmful and difficult-to-degrade pollutants, and has large discharge amount and wide pollution range. The large discharge of sewage will cause pollution to water, air and soil in different degrees, destroy the ecological environment, seriously threaten the drinking water safety of urban residents and the health of people, and have a serious impact on sustainable development.

[0003] In the past few decades, in order to achieve higher effluent quality, the required high pollution removal efficiency needs to use more and more equipment and more advanced new technologies, which leads to the increase of energy consumption in a single process. The common sewage treatment methods in sewage treatment plants are physical method, chemical method and biological method. Among them, the biological method has an irreplaceable role in degrading COD, BOD, sulfur, phosphorus, nitrogen and the like, and is an indispensable process in the sewage treatment process. Studies have shown that for sewage treatment plants of different scales, 30%-80% of energy is used for oxygen supply and power consumption of biological treatment; in the activated sludge method sewage treatment process, the energy consumption of degrading nitrogen or organic matter (BOD5, COD) mainly occurs in the aeration process. Excessive aeration, low oxygen utilization rate, long treatment time, high energy consumption and other problems have become the bottleneck of energy saving and emission reduction of sewage treatment plants. Therefore, reducing the aeration amount or canceling aeration has important significance for energy saving and carbon reduction.

[0004] CN115636506A discloses a vertical flow multi-chamber fully mixed anaerobic water treatment device. The device includes a sewage treatment zone, a reaction zone (first, second and third reaction zones connected in turn), a gas release zone and a sludge-water separation zone. Through the structure design of multiple up-and-down reverse flow in the reaction zone, the complete mixing of sludge and water can be realized; through the backflow of effluent to increase the inflow, the hydraulic shear is improved to some extent, and the sludge settlement phenomenon at the bottom of the reaction zone is reduced; through the parallel arrangement of the sludge-water separation zone and the reaction zone, the horizontal gravity flows into the sludge-water separation zone to replace the traditional three-phase separator with complex structure. However, the overall structure of the device is too complex, the reaction zone is provided too much, the control difficulty of each chamber is large, and it is not conducive to industrialization.

[0005] CN217148911U proposes an integrated simultaneous biological denitrification and desulfurization device for sewage treatment, a circular ring-shaped partition is arranged in the cylinder, a blow-off zone is formed in the partition, a reaction zone is formed outside the partition, a sludge concentration zone is arranged at the bottom of the cylinder, the bottom of the blow-off zone and the reaction zone is communicated with the sludge concentration zone, an aeration device is arranged at the bottom of the blow-off zone, an overflow plate is arranged at the upper part of the reaction zone, a sedimentation zone is formed between the overflow plate and the partition, a water outlet weir is arranged on the inner wall of the cylinder, a water outlet is arranged on the cylinder wall in the water outlet weir, and the top of the cylinder is connected with a tail gas absorption zone. The reaction zone, the blow-off zone, the sedimentation zone and the sludge concentration zone are integrated in the same device, which has the advantages of less equipment, small occupation area, easy installation and operation. However, the traditional air supply oxygen mode is still used, which has high energy consumption and low oxygen utilization rate, and the separation of the sedimentation zone, the reaction zone and the blow-off zone is not sufficient, which may cause three-phase separation difficulty.

[0006] CN202211107680.8 proposes an ozone oxidation-aerated biological filter water treatment system and sewage treatment method, which adopts pure oxygen aeration, on the one hand, the ozone tail gas is fully recycled, on the other hand, the problem of high oxygen cost of pure oxygen aeration is solved, so that the pure oxygen aeration has popularization. However, this method still belongs to bubble type oxygen supply, there is a mass transfer process from gas bubble to water body, which slows down the speed of microorganisms directly taking up oxygen from water body in biochemical reaction, and bubble type oxygen supply is easy to cause waste of oxygen.

[0007] Therefore, it is necessary to develop a more efficient and low-energy sewage treatment device and method, which has great significance for ecological environment protection field and promoting sewage resource utilization. SUMMARY

[0008] In view of the above problems, the present application provides a bubble-free oxygen supply biological method for sewage treatment based on hydraulic stirring to realize more efficient, low-energy and controllable dissolved oxygen sewage treatment.

[0009] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0010] A bubble-free oxygen supply biological method for sewage treatment based on hydraulic stirring, comprising a biological reactor, a hollow fiber membrane assembly and a mixer, wherein,

[0011] The bioreactor is provided with a reaction zone and a gas storage cavity arranged at the middle part above the reaction zone, the top of the gas storage cavity is provided with an exhaust port communicated with the outside, the bioreactor outside the reaction zone and the gas storage cavity is further sequentially provided with a sludge settling zone, a sludge-water separation module and a clear liquid zone from bottom to top, the top end of the reaction zone is provided with a partition plate for separating the sludge settling zone, at least one liquid lifting pipe communicated with the upper part of the reaction zone and the sludge settling zone is arranged on the partition plate, at least one gas stripping pipe communicated with the upper part of the reaction zone and the middle-upper part of the gas storage cavity is arranged in the gas storage cavity, and the bottom end inlet of the gas stripping pipe is higher than the bottom end inlet of the liquid lifting pipe.

[0012] The side wall of the bottom of the reaction zone is provided with a sewage inlet, a plurality of self-suction type hydraulic agitators are uniformly distributed in the circumferential direction of the lower part in the reaction zone, and the bottom liquid inlet end of the self-suction type hydraulic agitator is communicated to the sewage inlet; the side wall of the clear liquid zone is provided with a clear liquid outlet, the clear liquid outlet is connected to the water collecting device outside and the water inlet of the hollow fiber membrane assembly, the hollow fiber membrane assembly transports part of the refluxed clear liquid after oxygenation to the mixer, the water inlet of the mixer is connected to the water outlet of the hollow fiber membrane assembly and the sewage source, and the water outlet of the mixer is connected to the sewage inlet.

[0013] The reaction zone is filled with active sludge, and is used for biological treatment of sewage.

[0014] The application further preferably comprises that the gas storage cavity is surrounded by the cavity side wall, the cavity bottom surface and the top surface of the bioreactor, and the exhaust port is arranged on the top surface of the bioreactor in the gas storage cavity.

[0015] The application further preferably comprises that the liquid lifting pipe is a liquid lifting elbow pipe, comprising a straight pipe section at the top and an elbow pipe section at the bottom, the top of the straight pipe section extends into the sludge settling zone, the bottom of the elbow pipe section extends into the upper part of the reaction zone, and the central angle of the elbow pipe section is 60°-80°, so that better three-phase separation is achieved.

[0016] The application further preferably comprises that the self-suction type hydraulic agitator is further provided with a water distributor below, the water inlet of the water distributor is connected to the sewage inlet, and the water outlet of the water distributor is connected to the liquid inlet end of each self-suction type hydraulic agitator.

[0017] The application further preferably comprises that the self-suction type hydraulic agitator comprises a incident section, a mixing section, a contraction section and a diffusion section arranged in sequence from bottom to top, the bottom of the incident section is provided with a water inlet, the top of the diffusion section is provided with a jet port, at least one self-suction port is arranged on the outer side wall of the mixing section, the sewage entering through the incident section and the fluid sucked through the self-suction port are mixed in the mixing section, and then are jetted out through the top of the diffusion section.

[0018] In the present application, the number of the self-suction type hydraulic stirrers can be adjusted according to the diameter of the reactor, the self-suction ports formed on the self-suction type hydraulic stirrers are used to suck the fluid in the reaction zone, the sewage in the reaction zone is sucked into the self-suction type hydraulic stirrers through the self-suction ports under the action of the pressure difference, the sewage entering through the incident section is strongly mixed in the mixing section, and the sewage is sprayed out from the top spray ports of the self-suction type hydraulic stirrers in the form of uniform fluid.

[0019] It is further preferred that the length L1 of the incident section, the length L2 of the mixing section, the length L3 of the contraction section, the length L4 of the diffusion section and the total length L of the hydraulic stirrer satisfy the following relationships respectively: L1 / L = 0.35~0.43, L2 / L = 0.17~0.25, L3 / L = 0.04~0.08, L4 / L = 0.2~0.32; and the width d of the contraction section is greater than the length L3 of the contraction section.

[0020] It is further preferred that the inner side end of the incident section is a tapered section extending into the mixing section, and the tapered section is a circular truncated cone with an included angle β of 10°~32° with the vertical direction.

[0021] It is further preferred that a downcomer is arranged in the middle of the reaction zone, the bottom end of the downcomer extends to the bottom of the reaction zone above the self-suction type hydraulic stirrer, and the top end of the downcomer is connected to the bottom of the gas storage cavity.

[0022] It is further preferred that the horizontal height of the bottom surface of the gas storage cavity is lower than the sludge-water separation module, the lower end of the gas-lifting pipe extends into the upper part of the reaction zone through the sludge settling zone, the inner side end of the partition plate is connected to the bottom end of the gas storage cavity or the upper part of the downcomer, and the outer side end of the partition plate is connected to the inner side wall of the bioreactor in a downward inclination from inside to outside.

[0023] The horizontal height of the bottom surface of the gas storage cavity is higher than the sludge-water separation module, the lower end of the gas-lifting pipe extends into the upper part of the reaction zone through the sludge-water separation module and the sludge settling zone, the inner side end of the partition plate is connected to the upper part of the downcomer, and the outer side end of the partition plate is connected to the inner side wall of the bioreactor in a downward inclination from inside to outside.

[0024] It is further preferred that a sludge circulation outlet is arranged on the bottom side wall of the sludge settling zone, a sludge circulation inlet is arranged on the side wall of the middle of the reaction zone, the sludge circulation outlet and the sludge circulation inlet are connected through a pipeline outside the bioreactor, and the height of the sludge circulation inlet is higher than the top end of the self-suction type hydraulic stirrer.

[0025] It is further preferred that a sludge discharge port is formed on the bottom end of the reaction zone. The bottom of the reaction zone is preferably funnel-shaped, facilitating the discharge of sludge.

[0026] Further preferably, the sludge-water separation module uses a medium particle filter filler, which includes quartz sand, garnet or serpentine. Further, the size of the medium particle filter filler is preferably 0.5-2mm.

[0027] Further preferably, an overflow groove is arranged along the inner side wall of the clear liquid zone, which is composed of horizontally arranged plates and inclined plates, the outer end of the horizontally arranged plates is connected to the inner side wall of the bioreactor below the clear liquid outlet, the bottom end of the inclined plates is connected to the inner end of the horizontally arranged plates, and the angle between the inclined plates and the horizontally arranged plates is 50-80°.

[0028] Further preferably, the gas inlet and outlet of the hollow fiber membrane module are arranged on the left and right sides of the hollow fiber membrane module, the gas inlet of the hollow fiber membrane module is connected to an oxygen source through a gas inlet pipeline, the gas outlet is connected with a gas outlet pipeline, the gas outlet pipeline is provided with a gas outlet branch pipe connected to the gas inlet pipeline, which is used to return pure oxygen to the hollow fiber membrane module. The oxygen source is air or pure oxygen.

[0029] Further preferably, a standby aerator is arranged between the self-suction type hydraulic stirrer and the water distributor, the gas inlet of the standby aerator is connected to a gas source, and the gas source is independently arranged or shared with the oxygen source connected to the hollow fiber membrane module. Moreover, the bubbles generated by the aerator can also enhance the stirring under the entrainment of the self-suction type hydraulic stirrer.

[0030] It should be noted that the standby aerator does not need to be opened during normal use of the sewage treatment, and when the dissolved oxygen in the oxygen-rich water cannot meet the needs of the microorganisms in the reaction zone, the standby oxygen source is opened.

[0031] The present application also provides a bubble-free oxygen supply biological method for sewage treatment based on hydraulic stirring, which uses the above-mentioned sewage treatment equipment for sewage treatment, and includes the following steps:

[0032] (1) Under the action of the sewage pump, the sewage from the sewage pool is fully mixed with the oxygen-rich water from the hollow fiber membrane module through the mixer, and then enters the bioreactor through the sewage inlet, and when passing through the self-suction type hydraulic stirrer, the sewage self-suction into the reaction zone of the self-suction type stirrer is mixed with the sewage transported into the self-suction type stirrer, and then is sprayed out from the top;

[0033] (2) the sewage is continuously fed into the reaction zone by the self-suction type hydraulic stirrer, the activated sludge in the reaction zone degrades the pollutants in the sewage under aerobic, anaerobic or anoxic environment, the waste gas generated by the biodegradation is introduced into the gas storage cavity through the gas stripping pipe, the waste gas in the gas storage cavity is discharged to the outside through the valve control, and the liquid level in the reaction zone is controlled between the lower end of the liquid lifting pipe and the lower end of the gas stripping pipe;

[0034] (3) the sewage treated in step (2) is introduced into the sludge sedimentation zone from the liquid lifting pipe as the liquid level in the reaction zone gradually rises, and then the activated sludge is settled downward and deposited on the partition plate after passing through the sludge-water separation module; the clear liquid continues to go upward to the clear liquid zone and is discharged through the clear liquid outlet;

[0035] (4) the clear liquid discharged in step (3) is controlled by the valve to be discharged to the outside water collecting device or be returned to the hollow fiber membrane assembly for oxygen enrichment;

[0036] (5) the oxygen source is introduced into the hollow fiber membrane assembly, dissolved in the clear liquid introduced into the hollow fiber membrane assembly in step (4), and the oxygen-enriched water rich in dissolved oxygen is discharged into the mixer after being discharged from the hollow fiber membrane assembly, mixed with the sewage and then introduced into the biological reactor for further biodegradation.

[0037] It is further preferred that the sludge deposited on the partition plate in step (3) is pumped back to the sludge circulation inlet from the sludge circulation outlet by the sludge circulation pump, introduced into the reaction zone and uniformly dispersed under the jetting action of the self-suction type hydraulic stirrer, so as to improve the utilization rate of the activated sludge; the activated sludge dies and deposits at the bottom of the reaction zone to become dead sludge after reaching the sludge age, and the dead sludge is periodically discharged to the sludge tank from the sludge discharge port.

[0038] It is further preferred that when the oxygen source is pure oxygen, the oxygen not yet dissolved into the clear liquid in the hollow fiber membrane assembly is returned to the hollow fiber membrane assembly after being discharged from the gas outlet of the hollow fiber membrane assembly, so as to improve the utilization rate of oxygen; when the oxygen source is air, the oxygen is directly discharged to the outside after being discharged from the gas outlet of the hollow fiber membrane assembly.

[0039] In the above sewage treatment process, the dissolved oxygen in each stage satisfies the following relationship:

[0040] c1=((V0-V1)·c1+V1·c3-ΔX·V0) / V0 ①

[0041] c3=V2·c2 / V1 ②

[0042] c2=(V2·c1+V·ε·ρ) / V2 ③

[0043] V1=V2+V3 ④

[0044] In the formula, c1 represents the dissolved oxygen concentration in the bioreactor, the dissolved oxygen concentration of the effluent from the effluent port, and the dissolved oxygen concentration of the backflow liquid entering the influent port; c2 represents the dissolved oxygen concentration of the backflow liquid discharged from the effluent port; c3 represents the dissolved oxygen concentration in the sewage entering the bioreactor from the sewage inlet; V represents the volume of the gas source entering the air inlet; V0 represents the total volume of the mixed liquid in the bioreactor; V1 represents the volume of the effluent discharged from the effluent port and the volume of the sewage entering the bioreactor from the sewage inlet; V2 represents the volume of the backflow liquid; V3 represents the volume of the effluent entering the collecting tank and the volume of the sewage entering the mixer from the sewage tank, that is, the treatment capacity of the process; ε represents the volume fraction of oxygen in the gas source entering the air inlet; ρ represents the density of oxygen in the gas source entering the air inlet; ΔX is the difference between the concentration of pollutants (such as BOD5, COD, ammonia nitrogen, etc.) in the sewage entering the bioreactor from the sewage inlet and the concentration of pollutants in the effluent discharged from the effluent port; and X represents the pollutants in the sewage.

[0045] Simplifying formulas ①-④, the functional relationship between the oxygen supply amount V·ε and c1, V3, ΔX, and V0 is: V·ε=(c1·V3+ΔX·V0) / ρ; the backflow ratio r=V2 / V1=V2 / (V3+V2)=1 / (V3 / V2+1).

[0046] The sewage treatment method described in the application, in the treatment process, according to the prior art known in the reaction zone, the dissolved oxygen concentration under aerobic conditions is ≥2.0 mg / L, the dissolved oxygen concentration under anaerobic conditions is ≤0.2 mg / L, and the dissolved oxygen concentration under anoxic conditions is 0.2-0.5 mg / L. Therefore, according to the different dissolved oxygen concentrations required by the reaction zone, by adjusting the effluent backflow ratio and the gas supply amount V of the gas source, the oxygen-rich water can reach the required dissolved oxygen concentration after mixing with the sewage. Therefore, it is more convenient to switch between aerobic, anaerobic, and anoxic environments for sewage treatment.

[0047] Compared with the prior art, the application has the following beneficial technical effects:

[0048] (1) The application uses a hollow fiber membrane module to prepare oxygen-rich water, which not only strengthens the dissolution of oxygen in water, but also ensures that there are no bubbles in the effluent, replacing the high-energy-consuming fan in the traditional aeration mode, which not only reduces the occupied area, but also reduces the energy consumption; and the effluent from the bioreactor is used as the water source, which does not pollute the hollow fiber membrane module.

[0049] (2) The self-suction type hydraulic stirrer used in the application is used to make the sewage enter the reactor, and the self-suction port can self-suck the sewage in the reaction zone, mix with the influent sewage, and then be sprayed out, which plays a role in stirring and strengthening the mixing and mass transfer of the sewage in the reaction zone.

[0050] (3) The sewage treatment equipment and method can continuously feed and discharge water, and the bubble-free oxygen supply mode effectively avoids the adverse effects of bubbles on activated sludge microorganisms, realizes the integration of reaction and three-phase separation of the entire biological reactor, simplifies the disadvantages of traditional reaction, sedimentation and drainage, and greatly improves the sewage treatment efficiency.

[0051] (4) The sewage treatment equipment and method can adjust the clear liquid reflux ratio and the oxygen source supply rate, so that the oxygen-rich water can reach the required dissolved oxygen concentration in the reaction zone after mixing with the sewage, and the operation is more convenient for switching the sewage treatment under different conditions of anaerobic, aerobic or anoxic. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0053] Figure 2 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0054] Figure 3 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0055] Figure 4 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0056] Figure 5 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0057] Figure 6 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0058] Figure 7 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0059] Figure 8 It is a bubble-free oxygen supply biological method sewage treatment process flowchart.

[0060] 1, biological reactor, 100, reaction zone, 110, self-suction type hydraulic stirrer, 111, incident section, 112, mixing section, 113, contraction section, 114, diffusion section, 115, self-suction port, 116, tapered section; 120, partition, 130, riser, 131, straight pipe section, 132, elbow section, 140, sewage inlet, 150, water distributor, 160, downcomer, 170, sludge discharge port, 180, sludge circulation inlet; 200, gas storage cavity, 210, cavity side wall, 220, cavity bottom surface, 230, exhaust port, 240, first exhaust valve, 250, gas lift pipe;

[0061] 300, sludge settling zone, 310, sludge circulation outlet, 400, sludge-water separation module, 500, clear liquid zone, 510, clear liquid outlet, 520, overflow tank, 521, horizontal plate, 522, inclined plate;

[0062] 2, hollow fiber membrane module, 201, clear liquid inlet, 202, oxygen-rich water outlet, 203, oxygen inlet, 204, second exhaust port, 3, mixer, 301, first inlet, 302, second inlet, 303, water outlet, 4, oxygen source, 5, water collection tank, 6, sewage tank, 7, sludge tank, 8, air compressor. DETAILED DESCRIPTION

[0063] The technical solutions of the present application will be described in detail below in combination with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, not all.

[0064] Embodiment 1

[0065] Reference Figures 1-2 The present embodiment provides a bubble-free oxygen supply biological wastewater treatment equipment based on hydraulic agitation, which comprises a biological reactor 1, a hollow fiber membrane module 2, a mixer 3, an oxygen source 4, a water collection tank 5 and a sewage tank 6, wherein,

[0066] The biological reactor 1 is provided with a reaction zone 100 and a gas storage cavity 200 arranged at the middle part above the reaction zone 100. The gas storage cavity 200 is formed by surrounding the cavity side wall 210, the cavity bottom surface 220 and the top surface of the biological reactor. The top surface of the biological reactor 1 in the gas storage cavity 200 is provided with an exhaust port 230. The exhaust port 230 is circumscribed by an air outlet pipeline, and the air outlet pipeline is provided with a first exhaust valve 240.

[0067] From bottom to top, the biological reactor 1 outside the reaction zone 100 and the gas storage cavity 200 is further provided with a sludge settling zone 300, a sludge-water separation module 400 and a clear liquid zone 500. The sludge-water separation module 400 separates the sludge settling zone 300 and the clear liquid zone 500. The top end of the reaction zone 100 is provided with a partition plate 120 for separating the sludge settling zone 300 and the reaction zone 100. The partition plate 120 is provided with at least one liquid lifting pipe 130 communicating the upper part of the reaction zone 100 and the sludge settling zone 300. The gas storage cavity 200 is provided with at least one gas stripping pipe 250 communicating to the upper part of the reaction zone 100 and the middle-upper part of the gas storage cavity 200. The bottom end inlet of the gas stripping pipe 250 is higher than the bottom end inlet of the liquid lifting pipe 130 in terms of horizontal height. The side wall of the clear liquid zone 500 is provided with a clear liquid outlet 510. The lower part of the reaction zone 100 is circumferentially distributed with a plurality of self-suction type hydraulic agitators 110.

[0068] The water inlet and water outlet opened on the upper and lower sides of the hollow fiber membrane module 2 are respectively a clear liquid inlet 201 and an oxygen-rich water outlet 202, and the oxygen inlet 203 and the second exhaust port 204 are respectively opened on the left and right sides, the first inlet 301, the second inlet 302 and the water outlet 303 are opened on the mixer 3; the inlet of the water collecting tank 5 and the clear liquid inlet 201 of the hollow fiber membrane module 2 are both connected to the clear liquid outlet 510, the oxygen inlet 203 of the hollow fiber membrane module 2 is connected to the oxygen source 4 through the gas inlet pipeline; the first inlet 301 and the second inlet 302 of the mixer 3 are respectively connected to the oxygen-rich water outlet 202 of the hollow fiber membrane module 2 and the sewage tank 6.

[0069] The sewage inlet 140 is opened on the sidewall of the bottom of the reaction zone 100, the outer side end of the sewage inlet 140 is connected to the water outlet 303 of the mixer 3, and the inner side end is connected to the bottom liquid inlet end of the self-suction type hydraulic stirrer 110; the reaction zone 100 is filled with activated sludge, and the bottom end of the reaction zone 100 is provided with a sludge discharge port 170. In this embodiment, the bottom of the reaction zone 100 is preferably funnel-shaped, which is convenient for discharging sludge.

[0070] The self-suction type hydraulic stirrer 110 is further provided with a water distributor 150 below, the water inlet of the water distributor 150 is connected to the sewage inlet 140, and the water outlet of the water distributor 150 is connected to the liquid inlet end of each self-suction type hydraulic stirrer 110.

[0071] The middle part of the reaction zone 100 is provided with a downcomer 160, the bottom end of the downcomer 160 extends vertically downward to above the self-suction type hydraulic stirrer 110, and the top end is connected to the bottom of the gas storage cavity 200.

[0072] As shown in Figures 3-5 The self-suction type hydraulic stirrer 110 includes an incident section 111, a mixing section 112, a contraction section 113 and a diffusion section 114 arranged in sequence from bottom to top, at least one self-suction port 115 is opened on the outer sidewall of the mixing section 112, the fluid entering through the incident section 111 and the fluid sucked through the self-suction port 115 are mixed in the mixing section 112, and then sprayed out through the spray port at the top of the diffusion section 114.

[0073] The length L1 of the incident section 111, the length L2 of the mixing section 112, the length L3 of the contraction section 113 and the length L4 of the diffusion section 114 and the total length L of the hydraulic stirrer satisfy the following relationships: L1 / L=0.35~0.43, L2 / L=0.17~0.25, L3 / L=0.04~0.08, L4 / L=0.2~0.32; the width d of the contraction section 113 is greater than the length L3 of the contraction section 113.

[0074] The inner end of the incident section 111 is a tapered section 116 extending into the mixing section. The tapered section 116 is frustum-shaped, and the angle β between its outer wall and the vertical direction is 10°~32°.

[0075] like Figure 1 As shown, a sludge circulation outlet 310 is provided on the bottom side wall of the sludge settling zone 300, and a sludge circulation inlet 180 is provided on the side wall in the middle of the reaction zone 100. The sludge circulation outlet 310 and the sludge circulation inlet 180 are connected by a pipe outside the bioreactor 1. The height of the sludge circulation inlet 180 is higher than the top spray port of the self-priming hydraulic agitator 110.

[0076] The bottom surface 220 of the gas storage chamber 200 is lower than the bottom surface of the sludge-water separation module 400. The lower end of the air lift pipe 250 passes through the sludge settling zone 300 and extends into the upper part of the reaction zone 100. The inner end of the partition 120 is connected to the bottom end of the gas storage chamber 200 or the upper part of the downcomer 160. The outer end of the partition 120 is inclined downward from the inside to the outside and connected to the inner wall of the bioreactor 1.

[0077] The mud-water separation module 400 uses a medium particle filter media, which includes one or more of quartz sand, garnet or serpentine, and the size of the medium particle filter media is 0.5~2mm.

[0078] Furthermore, an overflow trough 520 is provided along the inner wall of the clear liquid zone 500. The overflow trough 520 is composed of a horizontal plate 521 and an inclined plate 522 connected to each other. The outer end of the horizontal plate 521 is connected to the inner wall of the bioreactor 1 below the clear liquid outlet 510, and the bottom end of the inclined plate 522 is connected to the inner end of the horizontal plate 521. The inclined plate 522 and the horizontal plate 521 form an angle of 50° to 80°.

[0079] In this embodiment, the second exhaust port 204 of the hollow fiber membrane module 2 is externally connected to an exhaust pipe 205. The exhaust pipe 205 is equipped with an exhaust branch pipe 206 connected to the air inlet pipe, used to return oxygen to the hollow fiber membrane module 2. Both the exhaust pipe 205 and the exhaust branch pipe 206 are equipped with valves to regulate gas discharge. When the oxygen source is air, the air discharged through the second exhaust port 204 can be directly discharged into the environment through the exhaust pipe 205. When the oxygen source is pure oxygen, the oxygen discharged through the second exhaust port 204 is circulated back into the hollow fiber membrane module 2 through the exhaust branch pipe 206, thereby reducing oxygen waste.

[0080] Further, a backup aerator 190 is arranged between the self-suction type hydraulic stirrer 110 and the water distributor 150, the air inlet of the backup aerator is connected to an air source, which is independently arranged or shared with the oxygen source 4 connected to the hollow fiber membrane assembly 2. In the embodiment, the backup aerator 190 is connected to the air compressor 8 or the air blower outside the bioreactor 1. It should be noted that the backup aerator does not need to be opened during normal use of the sewage treatment.

[0081] In the embodiment, the sludge discharge port 170 is connected to the sludge tank 7 through a sludge discharge pipeline, and a sludge discharge valve and a sludge discharge pump are arranged on the sludge discharge pipeline.

[0082] The application also provides a bubble-free oxygen supply biological method for sewage treatment based on hydraulic stirring, which uses the above sewage treatment equipment to treat sewage, and includes the following steps:

[0083] (1) Under the action of the sewage pump, the sewage from the sewage tank 6 is fully mixed with the oxygen-rich water from the hollow fiber membrane assembly 2 through the mixer 3, and then enters the bioreactor 1 through the sewage inlet 140. When passing through the self-suction type hydraulic stirrer 110, the sewage is self-sucked into the reaction zone 100 of the self-suction type hydraulic stirrer 110 through the self-suction port 115 under the action of the pressure difference, and then is mixed with the sewage transported to the self-suction type hydraulic stirrer 110 through the pipeline, and then is sprayed from the top jet port;

[0084] (2) The sewage continuously enters the reaction zone 100 through the self-suction type hydraulic stirrer 110, and the activated sludge in the reaction zone 100 degrades the pollutants in the sewage under aerobic, anaerobic or anoxic conditions; at the same time, the waste gas generated by the biological degradation enters the gas storage chamber 200 through the gas stripping pipe 250, the waste gas in the gas storage chamber 200 is discharged through the adjustment of the first exhaust valve 240, and the gas pressure in the gas storage chamber 200 is controlled, so that the liquid level in the reaction zone 100 is controlled between the bottom inlet of the liquid lifting pipe 130 and the bottom inlet of the gas stripping pipe 250;

[0085] (3) The sewage after the biological degradation in step (2) enters the sludge settling zone 300 from the liquid lifting pipe 130 as the liquid level in the reaction zone 100 gradually rises, and then the activated sludge is separated from the water through the sludge-water separation module 400, and then the activated sludge is settled on the partition plate 120; the clear liquid reaches the clear liquid zone 500, and is discharged through the clear liquid outlet 510;

[0086] (4) The clear liquid discharged in step (3) is controlled by the valve to be discharged to the water collecting tank 5, and a part of the clear liquid is returned to the hollow fiber membrane assembly 2 through the clear liquid inlet 201;

[0087] (5) Pure oxygen or air enters the hollow fiber membrane module 2 from oxygen source 4 through oxygen inlet 203. The clear liquid that entered the hollow fiber membrane module 2 in step (4) is dissolved in the hollow fiber membrane module 2. The oxygen-enriched water rich in dissolved oxygen is discharged from oxygen-enriched water outlet 202 and then enters the mixer 3. It continues to be fully mixed with the sewage entering the mixer 3 and then transported to the bioreactor 1 for treatment. During this process, if the gas source is pure oxygen, the oxygen that has not yet dissolved in the clear liquid in the hollow fiber membrane module 2 is discharged from the second exhaust port 204 and then flows back to the hollow fiber membrane module 2 through oxygen inlet 203.

[0088] (6) The sludge deposited on the partition plate 120 after step (3) is pumped out from the sludge circulation outlet 310 and returned to the sludge circulation inlet 180 by the sludge circulation pump, enters the reaction zone 100, and is evenly dispersed under the spraying action of the self-priming hydraulic agitator 110. After the activated sludge reaches the sludge age, it will die and be deposited at the bottom of the reaction zone 100 to become dead sludge. The dead sludge is periodically discharged from the sludge outlet 170 to the sludge tank 7.

[0089] In the wastewater treatment equipment described in this invention, each connecting pipe is equipped with a regulating valve.

[0090] Example 2

[0091] like Figures 6-7 As shown, the wastewater treatment equipment in this embodiment differs from that in Embodiment 1 in that: in this invention, the riser pipe 130 is preferably a riser bend, including an upper straight pipe section 131 and a lower bend pipe section 132. The top of the straight pipe section 131 extends into the sludge settling zone 300, and the bottom of the bend pipe section 132 extends into the upper part of the reaction zone 100. The central angle of the bend pipe section 132 is 60°~80°.

[0092] Example 3

[0093] like Figure 8 As shown, the wastewater treatment equipment in this embodiment differs from that in Embodiment 1 in that: the horizontal height of the bottom surface 220 of the gas storage chamber is higher than that of the sludge-water separation module 400; the lower end of the air lift pipe 250 passes through the sludge-water separation module 400 and the sludge settling zone 300 and extends into the upper part of the reaction zone 100; the inner end of the partition 120 is connected to the upper part of the downcomer 160, and the outer end of the partition 120 is inclined downward from the inside to the outside and connected to the inner wall of the bioreactor 1.

[0094] Example 4

[0095] The wastewater treatment equipment and method based on the non-bubble oxygen supply biological method with hydraulic agitation described in Embodiment 1 is used to treat wastewater, and the standby aeration device is not turned on. In this embodiment, the height of the biological reactor 1 is 1.8 m, the diameter is 400 mm, and the treatment capacity is 50 L / h; the bottom of the reaction zone 100 is circumferentially uniformly provided with three self-suction hydraulic agitators, and the total length L of each self-suction hydraulic agitator is 210 mm, and the parameters of each section are L1=85.6 mm, L2=43.2 mm, L3=11.8 mm, L4=69.4 mm, d=17.2 mm, β=14.3°, and a pair of self-suction ports 115 are symmetrically provided on the side wall of the mixing section of each self-suction hydraulic agitator. A pair of liquid lifting pipes 130 are symmetrically provided on the two sides of the partition plate 120, and two pairs of vertical gas lifting pipes 250 are symmetrically provided in the gas storage cavity 200.

[0096] The wastewater treatment equipment in the control group 1 is different from the above wastewater treatment equipment in that ordinary mechanical aeration is used for oxygen supply, and there is no self-suction hydraulic agitation device, hollow fiber membrane assembly, and mixer.

[0097] Under the condition that no activated sludge is added and the same amount of gas is supplied, the time required for the dissolved oxygen in the reaction zone of the wastewater treatment equipment to reach saturation from 0 is 10 minutes, and the time required for the reaction zone of the control group 1 is 38 minutes, and the oxygen dissolution rate is increased by 2.8 times.

[0098] Under the condition that the inlet flow rate is the same, the wastewater is treated by using aerobic activated sludge, and the BOD5 concentrations in the wastewater tank and the collection tank are measured after the two sets of equipment are stably operated for several days, and the results are recorded in Table 1.

[0099] Table 1 BOD5 removal rate and energy consumption

[0100]

[0101] As can be seen from the results in Table 1, under the condition that the BOD5 concentration of the wastewater source wastewater inlet is the same, the BOD5 concentration of the clear liquid after being treated by the wastewater treatment equipment in this embodiment is significantly lower than that of the control group 1, the removal efficiency of BOD5 is significantly higher than that of the control group, and the BOD5 that can be degraded per unit energy consumption (specific energy consumption) is increased by 4.3 times.

[0102] Embodiment 5

[0103] The same wastewater treatment equipment and process flow as in Embodiment 4 are used, the wastewater is treated by using aerobic activated sludge, and the COD concentrations in the wastewater tank and the collection tank are measured after stable operation for several days, and the results are recorded in Table 2.

[0104] The control group 2 adopts the same sewage treatment equipment as the control group 1, the sewage quality and the microorganism concentration are the same as those in example 5, under the condition that the inlet flow is the same, the COD concentration in the sewage tank and the collecting tank after the device is stably operated for several days is recorded, and the result is compared with that in example 5, and the result is recorded in table 2.

[0105] Table 2: Inlet and outlet COD concentration and removal rate

[0106]

[0107] From the result in table 2, it can be seen that under the condition that the COD concentration of the sewage source is the same, the COD concentration of the clear liquid after the sewage treatment equipment is treated is obviously lower than that of the control example, the removal efficiency of COD is obviously higher than that of the control example, and the COD that can be degraded per unit energy consumption (specific energy consumption) is increased by 5.2 times.

[0108] In summary, the hollow fiber membrane assembly is used to realize efficient oxygen dissolution, the self-suction type hydraulic stirrer is used as the hydraulic drive to realize bubble-free oxygen supply for the activated sludge and uniform mixing of the sludge and water, and the method has the advantages of high oxygen dissolution efficiency, good treatment effect, small occupied area and low energy consumption. In actual production, the sewage treatment device and method improved by the application have the advantages of obviously improved sewage treatment efficiency and greatly reduced cost.

[0109] The specific embodiments of the application are described in detail above, but they are only examples, and the application is not limited to the specific embodiments described above. Any equivalent modification and substitution to the application by those skilled in the art are also within the scope of the application. Therefore, any equivalent transformation and modification without departing from the spirit and scope of the application should be covered in the scope of the application.

Claims

1. A non-bubbling oxygen supply biological sewage treatment apparatus based on hydraulic agitation, characterized by, The device comprises a bioreactor, a hollow fiber membrane module and a mixer. The bioreactor is provided with a reaction zone and a gas storage cavity arranged at the middle part above the reaction zone, the top of the gas storage cavity is provided with an exhaust port, the bioreactor outside the reaction zone and the gas storage cavity is further provided with a sludge settling zone, a sludge-water separation module and a clear liquid zone from bottom to top, the top end of the reaction zone is provided with a partition plate for separating the sludge settling zone, at least one riser pipe is arranged on the partition plate and communicates with the upper part of the reaction zone and the sludge settling zone, at least one gas stripping pipe is arranged in the gas storage cavity and communicates with the upper part of the reaction zone and the middle part of the gas storage cavity, the bottom end inlet of the gas stripping pipe is higher than the bottom end inlet of the riser pipe. The sidewall of the bottom part of the reaction zone is provided with a sewage inlet, a plurality of self-suction hydraulic agitators are uniformly distributed in the circumferential direction of the lower part of the reaction zone, the bottom liquid inlet end of the self-suction hydraulic agitator is connected to the sewage inlet, the sidewall of the clear liquid zone is provided with a clear liquid outlet, the clear liquid outlet is connected to the outside water collecting device and the water inlet of the hollow fiber membrane module, the hollow fiber membrane module transports the part of the clear liquid backflow after oxygenation to the mixer, the water inlet of the mixer is connected to the water outlet of the hollow fiber membrane module and the sewage source, the water outlet of the mixer is connected to the sewage inlet, the middle part of the reaction zone is provided with a downcomer pipe, the bottom end of the downcomer pipe extends to the bottom of the reaction zone above the self-suction hydraulic agitator, and the top end is connected to the bottom of the gas storage cavity. The self-suction hydraulic agitator comprises an incident section, a mixing section, a contraction section and a diffusion section arranged in sequence from bottom to top, the bottom of the incident section is provided with a water inlet, the top of the diffusion section is provided with a jet port, at least one self-suction port is arranged on the outer sidewall of the mixing section, the sewage entering through the incident section and the fluid sucked through the self-suction port are mixed in the mixing section and then jetted out through the top of the diffusion section, the length L1 of the incident section, the length L2 of the mixing section, the length L3 of the contraction section and the length L4 of the diffusion section and the total length L of the hydraulic agitator satisfy the following relationships: L1 / L=0.35~0.43, L2 / L=0.17~0.25, L3 / L=0.04~0.08, L4 / L=0.2~0.32, the width d of the contraction section is greater than the length L3 of the contraction section, the inner side end of the incident section is a tapered section extending into the mixing section, the tapered section is a circular truncated cone, and the included angle β between the outer sidewall and the vertical direction is 10°~32°.

2. A non-bubbling oxygen supply biological sewage treatment apparatus based on hydraulic agitation according to claim 1, characterized in that, The gas storage cavity is surrounded by the cavity sidewall, the cavity bottom surface and the top surface of the bioreactor, and the exhaust port is arranged on the top surface of the bioreactor in the gas storage cavity, the sludge-water separation module adopts a medium particle filter filler.

3. The apparatus for wastewater treatment by a non-bubbling oxygen supply biological method based on hydraulic agitation according to claim 1, characterized in that, The riser pipe is a riser elbow pipe, comprising a straight pipe section at the top and a bend pipe section at the bottom, the top of the straight pipe section extends into the sludge settling zone, the bottom of the bend pipe section extends into the upper part of the reaction zone, and the central angle of the bend pipe section is 60°~80°.

4. The apparatus for wastewater treatment by a non-bubbling oxygen supply biological method based on hydraulic agitation according to claim 1, characterized in that, The water distributor is connected to the sewage inlet at the water inlet and connected to each self-suction hydraulic stirrer at the water outlet.

5. The apparatus for wastewater treatment by a non-bubbling oxygen supply biological method based on hydraulic agitation according to claim 1, characterized in that, The bottom surface of the gas storage cavity is lower than the sludge-water separation module, the lower end of the gas lift pipe extends into the upper part of the reaction zone through the sludge settling zone, the inner end of the baffle is connected to the bottom end of the gas storage cavity or the upper part of the downcomer, and the outer end of the baffle is connected to the inner side wall of the bioreactor in a downward inclination from inside to outside. The bottom surface of the gas storage cavity is higher than the sludge-water separation module, the lower end of the gas lift pipe extends into the upper part of the reaction zone through the sludge-water separation module and the sludge settling zone, the inner end of the baffle is connected to the upper part of the downcomer, and the outer end of the baffle is connected to the inner side wall of the bioreactor in a downward inclination from inside to outside.

6. The apparatus for water treatment by a non-bubbling oxygen supply biological method based on hydraulic agitation according to claim 1, characterized in that, A sludge circulation outlet is arranged on the side wall of the bottom of the sludge settling zone, a sludge circulation inlet is arranged on the side wall of the middle of the reaction zone, the sludge circulation outlet and the sludge circulation inlet are connected through a pipeline outside the bioreactor, and the height of the sludge circulation inlet is higher than the top end of the self-suction hydraulic stirrer.

7. The apparatus for water treatment by a non-bubbling oxygen supply biological method based on hydraulic agitation according to claim 1, characterized in that, An overflow tank is arranged along the inner side wall of the clear liquid zone, the overflow tank is composed of horizontally arranged plates and inclined plates, the outer end of the horizontally arranged plate is connected to the inner side wall of the bioreactor below the clear liquid outlet, the bottom end of the inclined plate is connected to the inner end of the horizontally arranged plate, and the inclined plate and the horizontally arranged plate form an included angle of 50°-80°.

8. The apparatus for water treatment by a non-bubbling oxygen supply biological method based on hydraulic agitation according to claim 1, characterized in that, The gas inlet and the gas outlet of the hollow fiber membrane module are arranged on the left and right sides of the hollow fiber membrane module, the gas inlet of the hollow fiber membrane module is connected to an oxygen source through a gas inlet pipeline, an exhaust pipeline is connected to the gas outlet, and an exhaust branch pipeline connected to the gas inlet pipeline is arranged on the exhaust pipeline, for returning pure oxygen to the hollow fiber membrane module.

9. A non-bubbling oxygen supply biological wastewater treatment method based on hydraulic agitation, characterized by, The sewage treatment equipment is used for sewage treatment, and the sewage treatment process comprises the following steps: (1) under the action of the sewage pump, the sewage from the sewage pool is fully mixed with the oxygen-rich water from the hollow fiber membrane module through the mixer and then enters the bioreactor through the sewage inlet, the sewage flowing into the self-suction hydraulic stirrer is mixed with the fluid self-suction into the self-suction hydraulic stirrer and then sprayed out from the top end; (2) the sewage continuously enters the reaction zone through the self-suction hydraulic stirrer, the activated sludge in the reaction zone degrades the pollutants in the sewage in an aerobic, anaerobic or anoxic environment, the waste gas generated by the biodegradation enters the gas storage cavity through the gas lift pipe, the waste gas in the gas storage cavity is discharged to the outside through the valve control, the gas pressure in the gas storage cavity is controlled, and the liquid level in the reaction zone is controlled between the lower end of the riser and the lower end of the gas lift pipe; (3) the sewage after the biodegradation in step (2) enters the sludge settling zone from the riser as the liquid level in the reaction zone gradually rises, then passes through the sludge-water separation module, the activated sludge settles downward and deposits on the baffle, and the clear liquid continues to rise to the clear liquid zone and is discharged through the clear liquid outlet; (4) The supernatant discharged in step (3) is controlled by a valve to discharge part of the supernatant to an external water collecting device and part of the supernatant is returned to the hollow fiber membrane module for oxygenation; (5) An oxygen source enters the hollow fiber membrane module, dissolves in the supernatant entering the hollow fiber membrane module in step (4) in the hollow fiber membrane module, and the oxygen-enriched water rich in dissolved oxygen is discharged into the mixer, and then is fully mixed with the sewage and enters the bioreactor for further biodegradation.

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