Variable hydraulic circulation mud membrane composite sequencing batch bioreactor and operation method thereof

Abstract

The present invention discloses a variable hydraulic circulation mud film composite sequencing batch bioreactor and an operation method thereof, which relate to the technical field of sewage treatment, comprising: a variable hydraulic circulation reaction zone and a variable reaction clarification zone, which are connected at the bottom through a first vertical baffle; a second vertical baffle and a third vertical baffle, which divide the variable hydraulic circulation reaction zone into three reaction zones, which are connected through the top and the bottom, and each reaction zone is respectively provided with a fixed bed biological filler and an aerator; a water inlet pipe, which is arranged at the upper part of the first reaction zone and is also connected to a phosphorus removal and dosing mixing reactor; a moving bed biological carrier, which is arranged in the variable reaction clarification zone, and is respectively provided with an aerator and a siphon outlet weir at the bottom and the top, and a mud discharge pipe and a mud discharge pump are connected at the bottom of the variable reaction clarification zone; the effective volume ratio of the first reaction zone, the second reaction zone, the third reaction zone and the variable reaction clarification zone is 1:(1-2):1:1.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and more specifically, relates to a variable hydraulic circulation mud membrane composite sequencing batch bioreactor and an operation method thereof. Background Art

[0002] Rural sewage quality and quantity vary greatly, and the small scale and scattered locations of these treatment sites make stable operation difficult and management challenging. In recent years, industry technicians have developed targeted treatment technologies for small and medium-sized wastewater resource utilization. Traditional sequencing batch bioreactor (SBR) technology boasts the temporal characteristics of an ideal plug flow reactor, effectively removing various pollutants by varying the timing. Its settling sequence is an ideal static sedimentation state, eliminating the need for sludge or mixed liquor return systems. It effectively treats recalcitrant organic matter, offering certain advantages and becoming a key technology for small and medium-sized wastewater resource utilization. Since its inception, traditional SBR technology has evolved into a variety of improved technologies. To adapt to the characteristics of urban sewage, improved technologies such as ICEAS, CASS, UNITANK, DAT-IAT, and MSBR have emerged. Some of these technologies alter the ideal plug flow, others disrupt the ideal settling process, and still others introduce sludge return, all of which diminish the advantages of traditional SBR technology to varying degrees. To adapt to the characteristics of rural sewage, existing improvement methods primarily include altering the influent and effluent forms, increasing stability through the addition of biofillers to form activated sludge and biofilm composites, and modifying operating methods to enrich specialized bacteria and achieve energy savings and consumption reductions. However, these improvements still present varying degrees of practical challenges.

[0003] The decanter is a key outlet device in traditional SBR technology. Its complex structure and poor reliability make it difficult to maintain in small and medium-sized reactors. An existing patent discloses a decanter-free SBR technology, which uses a central water distributor for water inlet at the bottom and a fixed overflow weir at the top for water outlet. The operation is simplified to a three-step sequence of water inlet and outlet, aeration, and sedimentation and sludge removal. This technology not only maintains a fully mixed flow pattern, ideal push flow, and ideal sedimentation, but also features a simple structure, relatively constant operating water level, fewer equipment, and higher reliability. This technology has significantly promoted the application of SBR technology in small and medium-sized wastewater treatment plants. However, in actual application of this patented technology, the suspended solids (SS) in the effluent is relatively high and difficult to stabilize below 20 mg / L, affecting the effluent compliance with standards. The main reasons are the following two defects that are difficult to resolve: First, after the water inlet and outlet sequence of the reactor, if no precipitation measures are set, the aeration reaction sequence will disturb the water level and the mud-water mixture will overflow the effluent weir, resulting in high effluent SS; Second, although the water inlet and outlet method adopts the design method of a vertical flow sedimentation tank, the SBR inlet flow rate is difficult to control and difficult to stabilize, which inevitably disturbs the sludge settled at the bottom of the tank. Even if the reactor is manufactured and installed to high standards, it is still difficult to ensure uniform water distribution, and local hydraulic short-flow is easily formed, resulting in high effluent SS. To address the first defect, there are two existing dewatering methods: one is to form a pathway through the central water distributor, the SBR inlet pipe slightly below the outlet weir, and the water pump, allowing a portion of the mixed liquid at the bottom of the tank to flow back to the regulating tank to achieve dewatering. This will cause SBR sludge to be lost and is rarely used. The second method is to lead a dewatering pipe from the upper end of the SBR slightly below the top outlet weir, and the supernatant passes through the dewatering electric valve and then flows back to the regulating tank, avoiding the backflow of SBR sludge. Due to the limited installation conditions of the electric valve, the failure rate is high and it is also rarely used. To address the second defect, in order to reduce the impact of hydraulic short-circuiting on the effluent water quality, the existing technology can only change the water distribution and outlet form, maintain a low SBR discharge ratio, and subsequently add a process step to remove SS. These measures will increase equipment, reduce treatment efficiency, increase cost investment, and increase maintenance difficulty.

[0004] In summary, it is necessary to continue to innovate the existing decanter-free sequencing batch reactor and its operation method while retaining its existing advantages, solve the problem of high SS in the effluent, and form a new SBR technology that is more stable, has lower cost investment, can meet different resource utilization needs, and is easier to maintain. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of the existing technology and provide a variable hydraulic circulation mud membrane composite sequencing batch bioreactor and its operation method to solve the problem of high suspended solids (SS) in the effluent, forming a new SBR technology that is more stable, has lower cost investment, can meet different resource utilization needs, and is easier to maintain.

[0006] In order to achieve the above object, the present invention provides a variable hydraulic circulation mud membrane composite sequencing batch bioreactor, comprising:

[0007] A variable hydraulic circulation reaction zone and a variable reaction clarification zone are provided with a first vertical partition plate therebetween, and the variable hydraulic circulation reaction zone and the variable reaction clarification zone are connected through the bottom of the first vertical partition plate;

[0008] a second vertical baffle and a third vertical baffle, disposed in the variable hydraulic circulation reaction zone, the second vertical baffle and the third vertical baffle dividing the variable hydraulic circulation reaction zone into a first reaction zone, a second reaction zone, and a third reaction zone; the first reaction zone, the second reaction zone, and the third reaction zone are connected through the top and the bottom; a fixed bed biological filler is disposed in the first reaction zone, the second reaction zone, and the third reaction zone, respectively; a first microporous aerator, a second macroporous aerator, and a third microporous aerator are disposed at the bottom of the first reaction zone, the second reaction zone, and the third reaction zone, respectively;

[0009] a water inlet pipe, one end of which is arranged at the upper part of the first reaction zone, and the other end of which is connected to the phosphorus removal and dosing mixing reactor;

[0010] A moving bed bio-carrier is arranged in the variable reaction and clarification zone, wherein a fourth large-pore aerator and a siphon outlet weir are respectively provided at the bottom and top of the moving bed bio-carrier, the siphon outlet weir is connected to the outlet pipe, and a mud discharge pipe and a mud discharge pump are connected to the bottom of the variable reaction and clarification zone;

[0011] The ratio of the effective volumes of the first reaction zone, the second reaction zone, the third reaction zone and the variable reaction clarification zone is 1:(1-2):1:1.

[0012] Optionally, the siphon outlet weir includes an outlet weir trough, a siphon pipe and a scum baffle, the siphon pipe includes a left vertical pipe and a right vertical pipe, the length ratio of the left vertical pipe to the right vertical pipe is (0.5~0.8):1, the distance between the lower end of the right vertical pipe and the bottom of the outlet weir trough is 50~100mm, and the outlet pipe is 100~200mm higher than the bottom of the outlet weir trough.

[0013] Optionally, the first microporous aerator, the second macroporous aerator, the third microporous aerator and the fourth macroporous aerator are connected to the first air source, the second air source, the third air source and the fourth air source respectively; the first microporous aerator, the second macroporous aerator and the third microporous aerator are all higher than the lower ends of the second vertical baffle and the third vertical baffle; the fourth macroporous aerator is higher than the lower end of the first vertical baffle.

[0014] Optionally, a first perforated filter plate and a second perforated filter plate are provided in the middle of the variable reaction clarification zone, and the first perforated filter plate and the second perforated filter plate are respectively provided at the lower part and the upper part of the moving bed bio-carrier.

[0015] Optionally, the first perforated filter plate and the second perforated filter plate are in the form of circular hole plates or grid-shaped hole plates, the diameter of the circular holes of the circular hole plates is less than 15 mm, the grid spacing of the grid-shaped hole plates is less than 10 mm, the opening rate of the first perforated filter plate and the second perforated filter plate is greater than 60%, and the material of the first perforated filter plate and the second perforated filter plate is 304 stainless steel.

[0016] Optionally, the fixed bed biofiller is a vertically suspended combined fiber biofiller, the material of the fixed bed biofiller is one or more of polyethylene, polypropylene, and formaldehyde-chemical fiber, and the filling rate of the fixed bed biofiller is 60% to 80%.

[0017] Optionally, the moving bed bio-carrier is one or more of a columnar honeycomb suspended bio-carrier and a porous sponge suspended bio-carrier, the material of the moving bed bio-carrier is one or more of polyethylene, polypropylene, polyurethane, and calcium alginate, and the filling rate of the moving bed bio-carrier is 40% to 70%.

[0018] The present invention also provides an operating method of a variable hydraulic circulation mud membrane composite sequencing batch bioreactor, utilizing the variable hydraulic circulation mud membrane composite sequencing batch bioreactor, the operating method comprising:

[0019] After the variable hydraulic circulation mud film composite sequencing batch bioreactor completes the microbial startup culture and domestication and forms a system of activated sludge and filler biofilm symbiosis, it enters normal operation. The normal operation cycle includes A water inlet and outlet timing sequence, B precipitation timing sequence, C anoxic reaction timing sequence, D aerobic reaction timing sequence, E sedimentation timing sequence and F sludge discharge timing sequence. After the above six timing sequences are completed, it enters the next cycle and operates in continuous cycle batches.

[0020] Optionally, A water inlet and outlet timing sequence: water starts to flow into the water inlet pipe, the second macroporous aerator aerates the second reaction zone to form an upward flow, the first reaction zone and the third reaction zone form a downward flow, and a large-scale hydraulic circulation is maintained on both sides; under the action of the inflowing water, the variable reaction clarification zone forms an upward flow, and the moving bed biological carrier intercepts the activated sludge; at the same time, the water level increases from W1 to W2, the siphon pipe in the siphon outlet weir is gradually submerged, and the outlet weir trough and the siphon pipe in the siphon outlet weir both have water outlet until the water inlet and outlet timing sequence ends, at which time the water inlet pipe stops flowing; the water inlet and outlet timing sequence is maintained for 40 to 60 minutes;

[0021] B. Precipitation sequence: After the water inlet and outlet sequence ends, the second macroporous aerator maintains operation, the water level starts to drop from W2, the outlet weir stops discharging water, and the siphon continues to discharge water under the action of the right water seal and siphon. When the water level drops to W1, the left water seal of the siphon is broken, and water discharge completely stops until the end of the precipitation sequence. The precipitation sequence is maintained for 2 to 8 minutes.

[0022] C. Anoxic reaction sequence: After the precipitation sequence ends, the second macroporous aerator remains in operation to maintain the dissolved oxygen in the variable hydraulic circulation reaction zone at 0.1-0.6 mg / L until the anoxic reaction sequence ends; the anoxic reaction sequence is maintained for 10-60 minutes;

[0023] D. Aerobic reaction sequence: After the anoxic reaction sequence ends, the first microporous aerator, the third microporous aerator, and the fourth macroporous aerator aerate the first reaction zone, the third reaction zone, and the variable reaction clarification zone. The second macroporous aerator stops operating. The first reaction zone and the third reaction zone form an upward flow, and the second reaction zone forms a downward flow. A small-scale hydraulic circulation opposite to the previous one is maintained, and the dissolved oxygen in the variable hydraulic circulation reaction zone is maintained at 2-4 mg / L. The moving bed biological carriers and the retained activated sludge begin to suspend and participate in the biological reaction until the aerobic reaction sequence ends. The aerobic reaction sequence is maintained for 60-180 minutes.

[0024] E Sedimentation Sequence: After the aerobic reaction sequence ends, the first microporous aerator, the third microporous aerator, and the fourth macroporous aerator stop operating, the second macroporous aerator resumes operation, the dissolved oxygen in the variable hydraulic circulation reaction zone decreases to anoxic state, the moving bed biological carriers in the variable reaction clarification zone stop suspending, and the activated sludge begins static sedimentation until the end of the sedimentation sequence; the sedimentation sequence is maintained for 30 to 60 minutes;

[0025] F Sludge discharge sequence: After the sedimentation sequence ends, the second large-pore aerator maintains operation, the dissolved oxygen in the variable hydraulic circulation reaction zone continues to decrease, the variable reaction clarification zone is completely clarified, the activated sludge is deposited at the bottom of the tank, the sludge pump runs, and the activated sludge at the bottom of the tank is discharged through the sludge discharge pipe until the sludge discharge sequence ends, at which time the sludge pump stops; the sludge discharge sequence is maintained for 0 to 10 minutes.

[0026] The present invention provides a variable hydraulic circulation mud membrane composite sequencing batch bioreactor and an operation method thereof, which has the following beneficial effects:

[0027] 1. The sequencing batch bioreactor is equipped with two vertical partitions in the variable hydraulic circulation reaction zone, dividing it into three reaction zones, and each zone is filled with fixed-bed biological fillers to form a composite activated sludge fixed-bed biofilm reactor. By setting different independently controllable aerators and air sources, it can not only form a circulating flow and achieve a completely mixed flow state, overcome hydraulic short-flow at the inlet and outlet time sequence, reduce the hydraulic dead zone with low flow rate of the biochemical reactor, and stabilize the effluent water quality, but also control the operation of the air source and change the hydraulic circulation direction to achieve anoxic stirring and aeration oxygenation functions at different time sequences. It can be flexibly adjusted to achieve various functions of removing carbon, nitrogen and phosphorus pollutants, improve operating efficiency and reduce operating costs.

[0028] 2. This sequencing batch bioreactor is equipped with a moving bed biological filler between the upper and lower filter plates in the variable reaction clarification zone. By setting up independently controllable macroporous aerators and air sources, it can not only increase the sedimentation area of the sedimentation sequence and ensure the SS removal effect of the effluent, but also form a composite activated sludge moving bed biofilm reactor by operating the air source during the anoxic and aerobic reaction sequences, achieving the function of further removing pollutants. At the same time, the sludge deposited in the biological filler is cleaned, eliminating the filler backwash system and increasing the volume utilization efficiency. The bottom sludge formed in the sedimentation sequence automatically flows back to the variable hydraulic circulation reaction zone, eliminating the need for a reflux pump and reducing equipment investment and maintenance.

[0029] 3. The sequencing batch bioreactor combines a composite activated sludge fixed-bed biofilm reactor with a composite activated sludge moving-bed biofilm reactor, which makes the reactor as a whole have better biodiversity and higher biological system stability. It has more obvious advantages in dealing with adverse conditions such as water quality shock, water volume shock, low temperature, and toxic substances.

[0030] 4. The sequencing batch bioreactor is equipped with a siphon outlet weir with a scum baffle above the variable reaction clarification zone. The siphon effect of the siphon tube is used to achieve precipitation. This not only improves the water production efficiency and effectively avoids the problem of sludge mixture overflowing the outlet weir during anoxic and aerobic reaction, but also works together with the scum baffle to prevent the impact of scum on the effluent SS.

[0031] 5. This sequencing batch bioreactor is suitable for small and medium-sized sewage treatment plants. It has a simpler and more reliable overall structure, effectively avoids hydraulic short-circuiting, has lower investment costs, is easy to maintain, has flexible operation methods, has strong shock load resistance, can adapt to seasonal changes, and cope with water inlet fluctuations. The SS of the effluent is stably below 15 mg / L, with higher operating efficiency, meeting various effluent resource utilization needs.

[0032] 6. In addition, operational reliability is a severe challenge currently faced by small and medium-sized sewage treatment systems. Gas source is a key equipment affecting operational reliability. The sequencing batch bioreactor is equipped with four independent gas sources, which not only makes it easy to flexibly adjust the gas supply to achieve energy saving, but also can maintain the basic functions of the process system even if 1 to 2 of the gas sources fail, thus improving operational reliability. In addition, the sequencing batch bioreactor eliminates the reflux system and backwash system, further reducing the equipment failure rate and further improving operational reliability.

[0033] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0035] Figure 1 The figure shows a structural schematic diagram of a variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to an embodiment of the present invention.

[0036] Figure 2 A flow chart showing an operating method of a variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to an embodiment of the present invention is shown.

[0037] Figure 3 A schematic structural diagram of a siphon weir according to an embodiment of the present invention is shown.

[0038] Description of reference numerals:

[0039] 1. Phosphorus removal and dosing mixing reactor; 2. Water inlet pipe; 3. Variable hydraulic circulation reaction zone; 301. First reaction zone; 302. Second reaction zone; 303. Third reaction zone; 304. Fixed-bed biological filler; 4. Variable reaction clarification zone; 401. First perforated filter plate; 402. Moving-bed biological carrier; 403. Second perforated filter plate; 5. Water outlet pipe; 6. First vertical baffle; 7. Second vertical baffle; 8. Third vertical baffle; 9. Siphon outlet weir; 901. Outlet weir trough; 902. Siphon pipe; 903. Scum baffle; 10. First microporous aerator; 11. Second macroporous aerator; 12. Third microporous aerator; 13. Fourth macroporous aerator; 14. First air source; 15. Second air source; 16. Third air source; 17. Fourth air source; 18. Mud discharge pipe; 19. Mud discharge pump. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Instead, these embodiments are provided to make the present invention more thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0041] like Figures 1 to 3 As shown, the variable hydraulic circulation mud film composite sequencing batch bioreactor specifically includes a phosphorus removal and dosing mixing reactor 1, an inlet pipe 2, a variable hydraulic circulation reaction zone 3, a variable reaction clarification zone 4, and an outlet pipe 5 connected in sequence, wherein a first vertical baffle 6 connected at the bottom is provided between the variable hydraulic circulation reaction zone 3 and the variable reaction clarification zone 4, and the variable hydraulic circulation reaction zone 3 includes a second vertical baffle 7 and a third vertical baffle 8, which divide the reaction zone into a first reaction zone 301, a second reaction zone 302 and a third reaction zone 303 connected at the top and bottom, the inlet pipe 2 is connected to the upper part of the first reaction zone 301, and a fixed bed biological filler 304 is provided in the three reaction zones. A first microporous aerator 10, a second macroporous aerator 11, and a third microporous aerator 12 higher than the lower end of the baffle are respectively provided at the bottom of the three reaction zones, and the three aerators are respectively connected to an independent first air source 14, a second air source 15 and a third air source 16; a first perforated aerator is provided in the variable reaction clarification zone 4. The filter plate 401 and the second perforated filter plate 403 are provided with a moving bed biological carrier 402 between the two perforated filter plates. A fourth large-pore aerator 13 is provided at the bottom, which is higher than the lower end of the first vertical partition 6. The aerator is connected to an independent fourth air source 17. A siphon outlet weir 9 is provided at the upper part of the variable reaction and clarification zone 4 and is connected to the outlet pipe 5. The bottom of the variable reaction and clarification zone 4 is connected to the sludge pump 19 through the sludge discharge pipe 18. The siphon outlet weir 9 is provided with an outlet weir groove 901, a siphon pipe 902 and a slag retaining wall. Plate 903, the number of siphon tubes is set according to the length of the outlet weir, and all siphon tubes are spaced at intervals of 50-100 mm. The length of the outlet weir is determined according to the inlet flow rate, and the outlet weir load should be less than 1.0 L / m / s. The ratio of the length of the left vertical pipe to the right vertical pipe is (0.5-0.8):1. The lower end of the right vertical pipe is 5-10 mm from the bottom of the outlet weir, and the bottom of the outlet pipe 5 is 100-200 mm higher than the bottom of the outlet weir 901.

[0042] In addition, the ratio of the effective volumes of the first reaction zone 301 , the second reaction zone 302 , the third reaction zone 303 , and the variable reaction clarification zone 4 is 1:(1-2):1:1.

[0043] The fixed bed biofiller is in the form of vertically suspended combined fiber biofiller, made of one or more of polyethylene, polypropylene, and formaldehyde-based fiber, with a filling rate of 60% to 80%.

[0044] The moving bed bio-carrier is in the form of one or more columnar honeycomb suspended bio-carriers and porous sponge suspended bio-carriers, and is made of one or more polyethylene, polypropylene, polyurethane, and calcium alginate, with a specific gravity of 0.95~1.05, a particle size of 25~50mm, and a filling rate of 40%~70%.

[0045] The first perforated filter plate 401 and the second perforated filter plate 403 are in the form of circular perforated plates or grid-shaped perforated plates. The opening rate of the perforated filter plates is greater than 60%, and the filter plate material can be selected from 304 stainless steel.

[0046] The second large-pore aerator 11 and the fourth large-pore aerator 13 can be in the form of an aeration perforated tube or a diffuser, with a pore diameter of 4-8 mm and a wind speed of 10-15 m / s at the orifice; the first microporous aerator 10 and the third microporous aerator 12 can be in the form of a disc, tube, or tower type, and can be made of rubber, polyurethane, ceramic, or plastic; all air sources connected to the aerator need to meet the aeration intensity of 4-8 m 3 / m 2 / h.

[0047] The operation method of the variable hydraulic circulation mud film composite sequencing batch bioreactor is to enter normal operation only after the sequencing batch bioreactor completes the microbial startup culture and domestication, and forms a system of activated sludge and filler biofilm symbiosis. This normal operation cycle can be divided into six time sequences, namely A water inlet and outlet sequence, B precipitation sequence, C anoxic reaction sequence, D aerobic reaction sequence, E sedimentation sequence, and F sludge discharge sequence. After the completion of these six time sequences, the next cycle is entered to achieve continuous cycle batch operation; when encountering unfavorable conditions such as strict water quality standards, high influent load or low temperature, the cycle cycle can be extended, the operation sequence can be adjusted, and according to the needs of phosphorus removal, a phosphorus removal agent can be injected before the phosphorus removal and dosing mixing reactor. The specific steps of the operation method are:

[0048] A. Inlet and outlet sequence: Water begins flowing into the inlet pipe, the first, third, and fourth air sources cease operation, the second air source begins operating, and the second large-pore aerator aerates the second reaction zone, creating an upward flow in the second reaction zone, which in turn creates a downward flow in the first and third reaction zones, maintaining a large-scale bilateral hydraulic circulation. Influx also creates an upward flow in the variable reaction clarification zone, where the moving bed bio-carriers accumulate to form a fixed sedimentation filter bed, which traps activated sludge and thus provides clarification. Simultaneously, the water level in the reactor increases from W1 to W2, the siphon gradually becomes submerged, and water flows from both the outlet weir and the siphon until the inlet pipe stops flowing at the end of the inlet and outlet sequence. This sequence typically lasts 40 to 60 minutes.

[0049] B. Precipitation Sequence: After the inlet and outlet sequence ends, the air source and aerator remain in the same operating state as in the previous sequence. The water level begins to drop from W2, and water flow from the outlet weir stops. Since the right vertical pipe outlet of the siphon is still below the water surface, a water seal is formed, thus creating a siphon effect, and the siphon continues to flow water. When the water level drops to W1, the water seal on the left side of the siphon is broken, and water flow from the siphon stops completely until the precipitation sequence ends. This sequence generally lasts 2 to 8 minutes.

[0050] C. Anoxic Reaction Sequence: After the precipitation sequence ends, all air sources and aerators maintain their operating states unchanged from the previous sequence, maintaining the dissolved oxygen level in the variable hydraulic circulation reaction zone at 0.1-0.6 mg / L until the anoxic reaction sequence ends. This sequence typically lasts 10-60 minutes.

[0051] D. Aerobic Reaction Sequence: After the anoxic reaction sequence ends, the first, third, and fourth air sources begin operation, while the second air source ceases operation. The first and third microporous aerators aerate the first and third reaction zones, creating an upward flow in these zones and a downward flow in the second reaction zone. This maintains a small-ratio hydraulic circulation inverse to the previous one (large-ratio hydraulic circulation means that, under the same air supply, aeration with the second macroporous aerator produces strong stirring but weak oxygenation, resulting in a greater circulating water flow rate. The opposite is true with aeration with the first and third microporous aerators, with a relatively smaller circulating water flow rate). The dissolved oxygen in the variable hydraulic circulation reaction zone is maintained at 2-4 mg / L. The fourth macroporous aerator aerates the variable reaction clarification zone, providing suspension power for the moving bed carriers. The carriers and retained activated sludge begin to suspend and participate in the biological reaction until the aerobic reaction sequence ends. This sequence typically lasts 60-180 minutes.

[0052] E Sedimentation Sequence: After the aerobic reaction sequence ends, the first, third, and fourth air sources are shut down, the second air source is turned on, an upflow is established in the second reaction zone, and a downflow is established in the first and third reaction zones. The dissolved oxygen in the variable hydraulic circulation reaction zone decreases to anoxic levels, the moving bed bio-carriers in the variable reaction clarification zone cease to be suspended, and the activated sludge begins static sedimentation until the end of the sedimentation sequence. This sequence typically lasts 30-60 minutes.

[0053] F. Sludge Discharge Sequence: After the sedimentation sequence ends, all air sources and aerators maintain their operating states as in the previous sequence. The dissolved oxygen in the variable hydraulic circulation reaction zone continues to decrease, the variable reaction clarification zone is completely clarified, and the activated sludge settles at the bottom of the tank. The sludge discharge pump operates, and the activated sludge at the bottom of the tank is discharged through the sludge discharge pipe until the sludge discharge sequence ends, at which point the sludge discharge pump stops. This sequence generally lasts 0 to 10 minutes.

[0054] The above operating steps can meet the summer wastewater recycling and miscellaneous water needs for greening, while winter greening is unnecessary. The operation method was adjusted to use water for ornamental landscapes, which requires nitrogen and phosphorus removal. The cycle was extended to 6 hours, and the operating sequence was adjusted to A→B→C→D→C→D→E→F. A phosphorus removal agent was injected before the phosphorus removal and dosing mixing reactor. Furthermore, during the anoxic reaction sequence, this sequence lasted 14 minutes in summer and 50 minutes in winter; during the aerobic reaction sequence, this sequence lasted 140 minutes in summer and 87 minutes in winter.

[0055] The implementation effects of the present invention include: the drainage ratio is increased from 25% to 33%, the operating efficiency is high, the return pump is eliminated, the investment cost is lower, and it is easier to maintain. In summer, the miscellaneous water greening standards for sewage recycling are stably met, and in winter, the water standards for ornamental landscape waterscapes for sewage recycling are stably met. The effluent SS is stably less than 10 mg / L, the operating method is flexible, and the impact load resistance is strong. It is suitable for small and medium-sized sewage resource treatment devices.

[0056] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A variable hydraulic circulation mud membrane composite sequencing batch bioreactor, characterized in that: include: A variable hydraulic circulation reaction zone and a variable reaction clarification zone are provided with a first vertical partition plate therebetween, and the variable hydraulic circulation reaction zone and the variable reaction clarification zone are connected through the bottom of the first vertical partition plate; a second vertical baffle and a third vertical baffle, disposed in the variable hydraulic circulation reaction zone, the second vertical baffle and the third vertical baffle dividing the variable hydraulic circulation reaction zone into a first reaction zone, a second reaction zone, and a third reaction zone; the first reaction zone, the second reaction zone, and the third reaction zone are connected through the top and the bottom; a fixed bed biological filler is disposed in the first reaction zone, the second reaction zone, and the third reaction zone, respectively; a first microporous aerator, a second macroporous aerator, and a third microporous aerator are disposed at the bottom of the first reaction zone, the second reaction zone, and the third reaction zone, respectively; a water inlet pipe, one end of which is arranged at the upper part of the first reaction zone, and the other end of which is connected to the phosphorus removal and dosing mixing reactor; A moving bed bio-carrier is arranged in the variable reaction and clarification zone, wherein a fourth large-pore aerator and a siphon outlet weir are respectively provided at the bottom and top of the moving bed bio-carrier, the siphon outlet weir is connected to the outlet pipe, and a mud discharge pipe and a mud discharge pump are connected to the bottom of the variable reaction and clarification zone; The ratio of the effective volumes of the first reaction zone, the second reaction zone, the third reaction zone and the variable reaction clarification zone is 1:(1-2):1:1; The siphon outlet weir includes a water outlet weir trough, a siphon pipe and a scum baffle. The siphon pipe includes a left vertical pipe and a right vertical pipe. The length ratio of the left vertical pipe to the right vertical pipe is (0.5~0.8):

1. The distance between the lower end of the right vertical pipe and the bottom of the water outlet weir trough is 50~100mm, and the water outlet pipe is 100~200mm higher than the bottom of the water outlet weir trough.

2. The variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to claim 1, characterized in that: The first microporous aerator, the second macroporous aerator, the third microporous aerator and the fourth macroporous aerator are connected to the first air source, the second air source, the third air source and the fourth air source respectively. The first microporous aerator, the second macroporous aerator and the third microporous aerator are all higher than the lower ends of the second vertical baffle and the third vertical baffle, and the fourth macroporous aerator is higher than the lower end of the first vertical baffle.

3. The variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to claim 1, characterized in that: A first perforated filter plate and a second perforated filter plate are provided in the middle of the variable reaction clarification zone. The first perforated filter plate and the second perforated filter plate are respectively provided at the lower part and the upper part of the moving bed bio-carrier.

4. The variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to claim 3, characterized in that: The first perforated filter plate and the second perforated filter plate are in the form of circular hole plates or grid-shaped hole plates. The diameter of the circular holes of the circular hole plates is less than 15 mm, the grid spacing of the grid-shaped hole plates is less than 10 mm, the opening rate of the first perforated filter plate and the second perforated filter plate is greater than 60%, and the material of the first perforated filter plate and the second perforated filter plate is 304 stainless steel.

5. The variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to claim 1, characterized in that: The fixed bed biological filler is a vertically suspended combined fiber biological filler. The material of the fixed bed biological filler is one or more of polyethylene, polypropylene, and formaldehyde-based fiber. The filling rate of the fixed bed biological filler is 60% to 80%.

6. The variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to claim 1, characterized in that: The moving bed bio-carrier is one or more of a columnar honeycomb suspended bio-carrier and a porous sponge suspended bio-carrier. The material of the moving bed bio-carrier is one or more of polyethylene, polypropylene, polyurethane, and calcium alginate. The filling rate of the moving bed bio-carrier is 40% to 70%.

7. A method for operating a variable hydraulic circulation mud membrane composite sequencing batch bioreactor, utilizing the variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to any one of claims 1 to 6, characterized in that: The operation method includes: After the variable hydraulic circulation mud film composite sequencing batch bioreactor completes the microbial startup culture and domestication and forms a system of activated sludge and filler biofilm symbiosis, it enters normal operation. The normal operation cycle includes A water inlet and outlet timing sequence, B precipitation timing sequence, C anoxic reaction timing sequence, D aerobic reaction timing sequence, E sedimentation timing sequence and F sludge discharge timing sequence. After the above six timing sequences are completed, it enters the next cycle and operates in continuous cycle batches.

8. The method for operating the variable hydraulic circulation mud membrane composite sequencing batch bioreactor according to claim 7, characterized in that: A. Water inlet and outlet sequence: water begins to flow into the water inlet pipe, the second macroporous aerator aerates the second reaction zone, forming an upward flow, and the first reaction zone and the third reaction zone form a downward flow, maintaining a large-scale hydraulic circulation on both sides; under the action of the inflowing water, the variable reaction and clarification zone forms an upward flow, and the moving bed biological carrier intercepts the activated sludge; at the same time, the water level increases from W1 to W2, the siphon pipe in the siphon outlet weir is gradually submerged, and the outlet weir trough and siphon pipe in the siphon outlet weir both discharge water until the water inlet and outlet sequence ends, at which point the water inlet pipe stops flowing; the water inlet and outlet sequence is maintained for 40 to 60 minutes; B. Precipitation sequence: After the water inlet and outlet sequence ends, the second macroporous aerator maintains operation, the water level starts to drop from W2, the outlet weir stops discharging water, and the siphon continues to discharge water under the action of the right water seal and siphon. When the water level drops to W1, the left water seal of the siphon is broken, and water discharge completely stops until the end of the precipitation sequence. The precipitation sequence is maintained for 2 to 8 minutes. C. Anoxic reaction sequence: After the precipitation sequence ends, the second macroporous aerator remains in operation to maintain the dissolved oxygen in the variable hydraulic circulation reaction zone at 0.1-0.6 mg / L until the anoxic reaction sequence ends; the anoxic reaction sequence is maintained for 10-60 minutes; D. Aerobic reaction sequence: After the anoxic reaction sequence ends, the first microporous aerator, the third microporous aerator, and the fourth macroporous aerator aerate the first reaction zone, the third reaction zone, and the variable reaction clarification zone. The second macroporous aerator stops operating. The first reaction zone and the third reaction zone form an upward flow, and the second reaction zone forms a downward flow. A small-scale hydraulic circulation opposite to the previous one is maintained, and the dissolved oxygen in the variable hydraulic circulation reaction zone is maintained at 2-4 mg / L. The moving bed biological carriers and the retained activated sludge begin to suspend and participate in the biological reaction. Until the end of the aerobic reaction sequence; the maintenance time of the aerobic reaction sequence is 60~180min; E Sedimentation Sequence: After the aerobic reaction sequence ends, the first microporous aerator, the third microporous aerator, and the fourth macroporous aerator stop operating, the second macroporous aerator resumes operation, the dissolved oxygen in the variable hydraulic circulation reaction zone decreases to anoxic state, the moving bed biological carriers in the variable reaction clarification zone stop suspending, and the activated sludge begins static sedimentation until the end of the sedimentation sequence; the sedimentation sequence is maintained for 30 to 60 minutes; F Sludge discharge sequence: After the sedimentation sequence ends, the second large-pore aerator maintains operation, the dissolved oxygen in the variable hydraulic circulation reaction zone continues to decrease, the variable reaction clarification zone is completely clarified, the activated sludge is deposited at the bottom of the tank, the sludge pump runs, and the activated sludge at the bottom of the tank is discharged through the sludge discharge pipe until the sludge discharge sequence ends, at which time the sludge pump stops; the sludge discharge sequence is maintained for 0 to 10 minutes.

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