CN114291902A - Wastewater treatment system - Google Patents

Abstract

The invention discloses a wastewater treatment system, which comprises a reactor, wherein a partition plate is arranged in the reactor, an anoxic tank is formed in the inner space of the reactor at the front side of the partition plate, a film forming tank is formed in the inner space of the reactor at the rear side of the partition plate, an aerobic tank is formed at the bottom of the reactor below the film forming tank, the anoxic tank is communicated with the lower part of the aerobic tank, a first aeration device is arranged in the aerobic tank, a backflow channel is arranged at the periphery of the top of the film forming tank, sludge mixed liquid in the film forming tank can turn to the backflow channel under the action of air stripping, the backflow channel is provided with an anoxic backflow pipeline connected to the anoxic tank and an aerobic backflow pipeline connected to the aerobic tank, a film combiner is arranged in the film forming tank, and the film combiner is connected with a water production pipe. The anoxic tank, the aerobic tank and the membrane tank are spatially arranged to form a horizontal and vertical combination to form an integrated three-zone, the space utilization rate is high, the occupied area is small, and the sludge can form a large circulation flow state among the anoxic tank, the aerobic tank and the membrane tank.

Description

Wastewater treatment system

Technical Field

The invention is used in the field of wastewater treatment, and particularly relates to a wastewater treatment system.

Background

The A/O MBR process has been successfully applied to industrial wastewater treatment in industries such as cosmetics, medicine, metal manufacturing, textile, slaughter houses, dairy products, food, beverage, paper and pulp, oil refining industry and chemical plants, landfill leachate and the like. However, in the practical application process, many problems still exist, for example, 1) the MBR membrane frame is fixed through a guide rail, the requirements on design and civil engineering construction are high, the problems of difficult installation, difficult fixation, floating of the membrane frame, uneven membrane aeration and the like exist, and great difficulty is caused to daily operation and maintenance; 2) the membrane aerator is arranged at the bottom of the membrane frame, so that sludge is easily collected at the bottom of the membrane pool; 3) the anoxic tank, the aerobic tank and the membrane tank are mutually independent and are generally horizontally arranged, so that the space utilization rate is low; the aerobic tank and the membrane tank which are horizontally arranged have different design depths, so that the design and construction of a civil engineering structure are adversely affected; 4) the aerobic tank aeration system, the membrane tank aeration system and the sludge return system of the A/OMBR are independent respectively, the equipment is various, and the system is complex; 5) the aerobic tank and the membrane tank adopt respective aeration systems, a large amount of tail gas in the aerobic tank needs to be deodorized and then is discharged, so that a large amount of tail gas is wasted, and Dissolved Oxygen (DO) of the aerobic tank and the membrane tank of the traditional A/O MBR is controlled to be more than 2mg/L and 5mg/L respectively, so that the defects of low aeration utilization rate, high energy consumption and the like exist on one hand; on the other hand, the high dissolved oxygen sludge mixed liquor in the membrane tank or the aerobic tank flows back to the anoxic tank, the anoxic environment of the anoxic tank can be damaged, and the denitrification is adversely affected, so that a practical limit value exists in the traditional denitrification of the A/O MBR. According to statistics, the main energy consumption sources of the traditional membrane bioreactor for typical municipal wastewater are as follows: a biochemical process aeration blower, a membrane scrubbing aeration blower, a sludge reflux pump, a suction pump, a lifting pump and an anoxic zone stirrer. Wherein the process aeration of the biochemical pool accounts for 42 percent of the energy consumption of the whole system, the membrane system aeration accounts for 34 percent, the sludge backflow accounts for 10 percent, the suction pump and the lift pump account for 4 percent, the stirring of the anoxic zone accounts for 9 percent, and the other energy consumption is about 1 percent.

Disclosure of Invention

The invention aims to solve at least one of the technical problems in the prior art and provides a wastewater treatment system, wherein an anoxic tank, an aerobic tank and a membrane tank are spatially arranged to form a horizontal and vertical combination to form an integrated three-zone, the space utilization rate is high, the occupied area is small, and the sludge can form a large circulation flow state among the anoxic tank, the aerobic tank and the membrane tank.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the utility model provides a wastewater treatment system, includes the reactor, the inside subregion baffle that is equipped with of reactor, the inner space of reactor in the front side of subregion baffle forms the oxygen deficiency pond, the inner space of reactor in the rear side of subregion baffle forms the membrane cisterna, the bottom of reactor in the below of membrane cisterna forms good oxygen pond, the oxygen deficiency pond with the lower part in good oxygen pond is linked together, be equipped with first aeration equipment in the good oxygen pond, membrane cisterna top periphery is equipped with the backward flow canal, mud mixed liquid in the membrane cisterna can overturn under the air stripping effect to the backward flow canal, the backward flow canal is equipped with and is connected to the oxygen deficiency return line in oxygen deficiency pond and be connected to good oxygen return line in good oxygen pond, be equipped with the membrane group ware in the membrane cisterna, the membrane group ware is connected and is produced the water pipe.

In some embodiments, the bottom end of the partition wall forms a dead center before extending to the bottom of the reactor, and the bottom end of the partition wall is provided with an inclined partition wall extending obliquely downward.

In some embodiments, an interface partition plate is arranged between the aerobic tank and the membrane tank, the interface partition plate is provided with a second aeration device, the second aeration device comprises a gas collection cavity and an air outlet pipe, the gas collection cavity is downward opened, the top end of the air outlet pipe penetrates through the interface partition plate to be communicated with the membrane tank, the lower end of the air outlet pipe extends downwards into the gas collection cavity from the top of the gas collection cavity, the lower end of the air outlet pipe is provided with a water sealing cap with an upward opening, a flow passage for intermittently discharging gas in the gas collection cavity is defined between the water sealing cap and the air outlet pipe, and the membrane group device is arranged at the top end of the air outlet pipe.

In some embodiments, the interface baffle separates the aerobic tank from the membrane tank, and an edge of the interface baffle is provided with a gas stripping channel for communicating the aerobic tank with the membrane tank.

In some embodiments, the bottom edge of the interface baffle is provided with a surrounding plate, the interface baffle forms an inverted cavity through the surrounding plate, a plurality of partition plates are arranged inside the surrounding plate, the cavity is divided into a plurality of gas collecting cavities by the partition plates, and each gas collecting cavity is provided with a gas outlet pipe and a water sealing cap.

In some embodiments, the first aeration device comprises a micro-porous aeration device connected to a fan via a conduit.

In some embodiments, a connecting sleeve is arranged in the middle of the water sealing cap, the water sealing cap is sleeved with the air outlet pipe through the connecting sleeve, and the water sealing cap can be adjusted up and down along with the connecting sleeve along the air outlet pipe.

In some embodiments, the membrane module comprises a membrane frame and a membrane module, the membrane module is mounted on the membrane frame, the membrane module comprises a membrane element and a water collecting box for collecting water produced by the membrane element, the water producing pipe is connected with the water collecting box, the membrane module enables the membrane module to obtain buoyancy required for floating in a membrane pool through a water drainage volume of the membrane frame, and the membrane element is immersed in the membrane pool when the membrane module floats in the membrane pool.

In some embodiments, the membrane module further comprises a floating member mounted to the membrane frame, the membrane module allowing the membrane module to obtain a desired buoyancy to float in the membrane tank by the displacement volume of the membrane frame and the floating member.

In some embodiments, the floating member comprises a pontoon mounted at the top of the membrane frame and/or a floating plate mounted at the side of the membrane frame.

One of the above technical solutions has at least one of the following advantages or beneficial effects:

1. the anoxic tank, the aerobic tank and the membrane tank are integrally designed, and form a horizontal and vertical combination in spatial arrangement to form an integrated three-zone, so that the space utilization rate is high, and the occupied area is small; the problems that the traditional MBR is an aerobic tank and a membrane tank which are horizontally arranged, the adverse effect on civil engineering structure design and construction is caused, the occupied area is large and the like are solved;

2. the aerobic tank aeration system and the membrane tank aeration system are simplified into a combined aeration system, and the defects of multiple devices, complex system, complex operation control, high operation energy consumption and the like caused by respective independence of the aerobic tank aeration system, the membrane tank aeration system and the sludge reflux system in the traditional A/O MBR are overcome. The combined aeration system only needs one set of aeration system of the aerobic tank as the power for the oxygen supply of the activated sludge, the membrane aeration and the sludge backflow, and realizes 'one-gas-three-purpose';

3. the sludge forms a large circulating flow state among the anoxic tank, the aerobic tank and the membrane tank, wherein the anoxic tank, the aerobic tank and the membrane tank are vertically and three-dimensionally arranged instead of being horizontally arranged, and can form a circulating flow by air lift in theory, so that the low-energy-consumption self-refluxing is realized. A water pump can be added to assist circulation as required to form an A/O MBR system, so that pollutant components such as COD, TN, ammonia nitrogen and the like can be removed efficiently;

4. compared with the traditional MBR process, only one set of aeration system of the aerobic tank is needed, biochemical oxygen supply, membrane aeration and anoxic tank gas stirring are met, power is provided for sludge mixed liquid backflow, the system is low in Dissolved Oxygen (DO) operation overall, the advantages of remarkable energy saving and consumption reduction are achieved, energy consumption can be saved by more than 50%, and the operation cost is greatly reduced;

5. the membrane group device does not need to be provided with a membrane aerator, thoroughly solves the problem of sludge collection caused by the traditional membrane aerator arranged at the bottom, does not need an aerator pipe, and simplifies the design, installation and maintenance.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of one embodiment of the present invention;

FIG. 2 is a schematic view showing the structure of a second aeration apparatus according to one embodiment shown in FIG. 1;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a schematic bottom structure view of the second aeration apparatus according to the embodiment shown in FIG. 2;

FIG. 5 is a schematic top view of the second aeration apparatus of one embodiment shown in FIG. 2;

FIG. 6 is a schematic diagram illustrating the operation of the second aeration apparatus according to the embodiment shown in FIG. 2;

FIG. 7 is a schematic structural diagram of one embodiment of a membrane module according to the present invention;

FIG. 8 is a schematic structural diagram of another embodiment of the membrane module of the present invention;

FIG. 9 is a graph showing the effect of treatment of COD in the example of the present invention;

FIG. 10 is a graph illustrating the effect of embodiments of the present invention on TN processing;

FIG. 11 is a graph showing the effect of ammonia nitrogen treatment according to the embodiment of the present invention;

FIG. 12 is a graph of the effect of embodiments of the present invention on MLSS/MLVSS and fan air volume;

FIG. 13 is a graph showing the effect of membrane permeability performance in one mode of operation of the embodiment of the present invention;

FIG. 14 is a graph showing the effect of membrane permeability on another mode of operation of the present invention.

Detailed Description

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the present invention, if directions (up, down, left, right, front, and rear) are described, it is only for convenience of describing the technical solution of the present invention, and it is not intended or implied that the technical features referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, it is not to be construed as limiting the present invention.

In the invention, the meaning of "a plurality" is one or more, the meaning of "a plurality" is more than two, and the terms of "more than", "less than", "more than" and the like are understood to exclude the number; the terms "above", "below", "within" and the like are understood to include the instant numbers. In the description of the present invention, if there is description of "first" and "second" only for the purpose of distinguishing technical features, it is not to be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the precedence of the indicated technical features.

In the present invention, unless otherwise specifically limited, the terms "disposed," "mounted," "connected," and the like are to be understood in a broad sense, and for example, may be directly connected or indirectly connected through an intermediate; can be fixedly connected, can also be detachably connected and can also be integrally formed; may be mechanically coupled, may be electrically coupled or may be capable of communicating with each other; either as communication within the two elements or as an interactive relationship of the two elements. The specific meaning of the above-mentioned words in the present invention can be reasonably determined by those skilled in the art in combination with the detailed contents of the technical solutions.

Fig. 1, 2 and 6 show a reference direction coordinate system of the embodiment of the present invention, and the embodiment of the present invention will be described below with reference to the directions shown in fig. 1, 2 and 6.

Referring to fig. 1, an embodiment of the present invention provides a wastewater treatment system, including a reactor 1, a partition 11 is disposed inside the reactor 1, an anoxic tank 2 is formed in the front side of the partition 11 in the internal space of the reactor 1, a membrane tank 3 is formed in the rear side of the partition 11 in the internal space of the reactor 1, an aerobic tank 4 is formed below the membrane tank 3 at the bottom of the reactor 1, and a first aeration device 41 is disposed in the aerobic tank 4, so that the membrane tank 3 can utilize the aeration tail gas of the aerobic tank 4 as the aeration of the membrane tank 3 to optimize the aeration energy consumption. The lower part of oxygen deficiency pond 2 and good oxygen pond 4 is linked together, and 3 top peripheries of membrane pond are equipped with backward flow canal 31, and the mud mixed liquor in the membrane pond 3 can turn over to backward flow canal 31 under the air stripping effect, and backward flow canal 31 is equipped with the oxygen deficiency return line that is connected to oxygen deficiency pond 2 and is connected to the good oxygen return line of good oxygen pond 4, is equipped with membrane group ware 5 in the membrane pond 3, and membrane group ware 5 is connected and is produced water pipe 51, can produce water, also can online backwash. The membrane components of the membrane component device 5 can be arranged in a single layer, a double layer, a single row or a double row, so that the gas-water ratio is reduced to the maximum extent, and the energy consumption is saved. In other words, the reactor 1 is divided into an anoxic tank 2, an aerobic tank 4 and a membrane tank 3 according to the distribution difference of Dissolved Oxygen (DO), wherein the anoxic tank 2 is a non-aerobic zone, and the Dissolved Oxygen (DO) is generally 0.2-0.5 mg/L. When nitrate, nitrite and sufficient organic matter are present, denitrification can be performed in the tank. The retention time is 0.5-2.0 h, the pH value is 7.0-8.0, and the sludge concentration is 10000-15000 mg/L. The aerobic tank 4 is an oxygen charging area, the retention time is 1.02-3.0 h, and the sludge concentration is 100002-15000 mg/L. The main functions are to degrade organic matters and carry out nitration reaction, and the pH value is 7.02-8.0. The membrane tank 3 is mainly a solid-liquid separation zone and is internally provided with a floating membrane group device 5, the oxygen-poor tail gas of the aerobic tank 4 is collected by an interface aerator and is converted into large bubbles to wash membrane filaments, membrane pollution is controlled, and the backflow of sludge mixed liquor is realized or facilitated through the air stripping effect. The selected membrane product is a hollow fiber ultrafiltration membrane (the aperture is 0.02-0.04 um), the membrane operation flux is 10-40 LMH, the retention time is 0.5-2.0 h, the sludge concentration is 10000-15000 mg/L, the pH is 7.0-8.0, and the Dissolved Oxygen (DO) is 0.5-6.0. In this zone, organic matter can be degraded and nitration can be carried out. The anoxic reflux ratio and the aerobic reflux ratio are 1.0-6.0.

Sewage enters the anoxic tank 2 through a water inlet pipeline and a pipe fitting through the water inlet pump 21, the anoxic tank 2 is communicated with the lower part of the aerobic tank 4, so that sludge mixed liquor in the anoxic tank 2 can be conveniently sent to the aerobic tank 4, the bottom of the aerobic tank 4 is provided with a first aeration device 41 for providing biochemical oxygen demand, and the first aeration device 41 is connected with an external fan 42 (air source). The membrane pool 3 is separated from the anoxic pool 2 by partition plates 11, a membrane group device 5 is arranged in the membrane pool 3, one end of a water production pipe 51 of the membrane group device 5 is connected with the membrane group device 5 through a flexible hose, and the other end of the water production pipe is connected with a water production tank 50 which is qualified in output quality. The water production pipe 51 can be provided with a water production pump 52 according to the requirement. Wherein, first aeration equipment 41 is the oxygen suppliment for activated sludge on the one hand, also can erode membrane group ware simultaneously, and effective control membrane pollutes, but also can regard as the power of mud backward flow. The periphery of the top of the membrane pool 3 is provided with a return channel 31, the sludge mixed liquor in the membrane pool 3 can be turned to the return channel 31 under the action of air lift, the two ends of the return channel 31 are respectively provided with an anoxic return pipeline and an aerobic return pipeline, and the sludge mixed liquor in the return channel can be respectively returned to the anoxic pool 2 and the aerobic pool 4 through the air lift or a return pump according to a certain return ratio, so that the Dissolved Oxygen (DO) of the whole system is reasonably distributed, and the purposes of efficiently denitrifying and removing organic pollutants are achieved.

The lower parts of the anoxic tank 2 and the aerobic tank 4 can be communicated by a plurality of ways such as arranging pipes, holes and the like, for example, in some embodiments, referring to fig. 1, the bottom end of the partition 11 forms a dead point before extending to the bottom of the reactor 1, and the space between the bottom end of the partition 11 and the bottom of the reactor 1 forms a channel for communicating the lower parts of the anoxic tank 2 and the aerobic tank 4, so that the sludge mixed liquid in the anoxic tank 2 flows to the aerobic tank 4.

Further, referring to fig. 1, the bottom end of the partition 11 is provided with an inclined partition 12 extending obliquely downward, the lower end of the inclined partition 12 extends forward, and the inclined partition 12 guides the airflow of the first aeration device 41 to prevent or reduce the aeration of the aerobic tank 4 from destroying the anoxic environment of the anoxic tank 2.

The gas of the first aeration device 41 can directly scour the membrane module 5, and can also scour the membrane module 5 intermittently after being collected, compared with small-bubble aeration, the large-bubble aeration can effectively remove the pollution on the surface of the membrane wire, increase the mass transfer convection on the surface of the membrane, and maintain the stable operation of the membrane flux. The key point is how to convert the micro-bubble aeration of the aerobic tank 4 into the large-bubble aeration required by the membrane tank 3 and more effectively maintain the stable operation of the membrane system. In some embodiments, referring to fig. 2, 3, 4 and 6, an interface partition plate 6 is arranged between the aerobic tank 4 and the membrane tank 3, the interface partition plate 6 is provided with a second aeration device 7, the second aeration device 7 comprises a gas collection chamber 71 and a gas outlet pipe 72, the gas collection chamber 71 is open downwards, the top end of the gas outlet pipe 72 passes through the interface partition plate 6 to be communicated with the membrane tank 3, the lower end of the gas outlet pipe 72 extends downwards into the gas collection chamber 71 from the top of the gas collection chamber 71, the lower end of the gas outlet pipe 72 is provided with a water sealing cap 73 with an upward opening, a flow passage for intermittently discharging gas in the gas collection chamber 71 is defined between the water sealing cap 73 and the gas outlet pipe 72, and the membrane group device 5 is arranged at the top end of the gas outlet pipe 72.

The interface clapboard 6 covers most of the interface area, so that the aeration tail gas of the aerobic tank 4 can be collected as much as possible, the second aeration device 7 with special design is arranged on the interface clapboard 6, and the second aeration device 7 is provided with a plurality of inverted gas collecting cavities 71 which can capture the small bubbles of the aeration tail gas of the aerobic tank 4. The gas stock in the gas collection cavity 71 gradually increases, the pressure of the gas stored in the gas collection cavity 71 gradually increases, water in the gas collection cavity 71 is gradually squeezed out from the bottom of the gas collection cavity 71, the water level in the gas collection cavity 71 gradually decreases, and when the pressure of the gas stored in the gas collection cavity 71 exceeds a critical release point, the gas in the gas collection cavity 71 overflows through the gas flow channel and the gas outlet pipe 72 in the form of large bubbles. The second aeration device 7 releases large bubbles on the membrane tank 3 side, thereby scouring the membrane filament surfaces and preventing membrane fouling, and thereafter the second aeration device 7 accumulates gas again in the gas collection chamber 71.

According to the technical scheme, small bubbles formed by aeration tail gas of the aerobic tank 4 can be collected and converted into large bubbles, the large bubbles are released into the membrane tank 3 above the aerobic tank 4, and the membrane group device 5 in the membrane tank 3 is washed to prevent membrane pollution. In the whole system, only the aerobic tank 4 is provided with the fan, but the membrane tank 3 is not provided with an independent fan, and the aeration tail gas of the aerobic tank 4 is fully utilized as the aeration purpose of the membrane tank 3, so that the energy-saving purpose is achieved. It can make full use of aeration and save energy consumption of aeration. Simultaneously, compare in little bubble, big bubble can be better prevent membrane pollution to the steady operation of more effective maintenance membrane system.

In some embodiments, referring to fig. 2, the aerobic tank 4 and the membrane tank 3 are separated by an interface baffle 6, and the edge of the interface baffle 6 is provided with a gas stripping channel 61 for communicating the aerobic tank 4 and the membrane tank 3. Can allow activated sludge with the flow rate which is several times of that of the produced water to enter the membrane tank 3 from the aerobic tank 4. Of course, the activated sludge will carry away a part of the aeration tail gas. The air stripping function of the aeration tail gas of the aerobic tank 4 can help share the load of the reflux pump, thereby achieving the purpose of energy conservation.

The interface clapboard 6 is provided with one or more second aeration devices 7, for example, in some embodiments, referring to fig. 2, 4 and 5, the bottom edge of the interface clapboard 6 is provided with a surrounding plate 62, the interface clapboard 6 forms an inverted cavity through the surrounding plate 62, the surrounding plate 62 is internally provided with a plurality of partition plates 63, the cavity is divided into a plurality of gas collecting cavities 71 by the partition plates 63, and each gas collecting cavity 71 is provided with an air outlet pipe 72 and a water seal cap 73. In this embodiment, the interface partition plate 6 covers most of the interface area, the aeration tail gas of the aerobic tank 4 can be collected as much as possible by the surrounding plate 62 at the edge to enter the inverted concave cavity, and the concave cavity is further partitioned by the partition plate 63, so that a plurality of gas collecting cavities 71 of the second aeration device 7 are formed on the interface partition plate 6, and a plurality of aeration points are formed on the interface partition plate 6, thereby providing more sufficient scouring for the membrane module. In addition, the arrangement of the partition plate 63 and the enclosing plate 62 greatly increases the overall strength of the interface baffle 6, and prolongs the service life of the whole device.

In some embodiments, referring to fig. 1 and 2, the first aeration device 41 comprises a micro-porous aeration device connected to a fan via a pipe. The microporous aeration device is arranged at the bottom of the aerobic tank 4, and can increase the mass transfer efficiency of oxygen.

The embodiment of the invention can be provided with a dissolved oxygen accurate control system, the dissolved oxygen accurate control system comprises a dissolved oxygen measuring instrument, a controller and the like which are arranged in the reactor 1, the dissolved oxygen in the reactor 1 is monitored in real time through the dissolved oxygen measuring instrument, and compared with a dissolved oxygen set value through the controller, the air quantity of the aeration fan is controlled by a feedback frequency converter to adjust the fan. The embodiment adopts the dissolved oxygen accurate control technology to control the air quantity of the fan in real time, and has high automation degree, strong impact resistance and stable process operation.

The water sealing cap 73 is sleeved outside the lower port of the air outlet pipe 72, the water sealing cap 73 can be positioned by an independent supporting structure, and can also be positioned by being connected with the air outlet pipe 72, for example, in some embodiments, referring to fig. 3, a connecting sleeve 74 is arranged in the middle of the water sealing cap 73, the water sealing cap 73 is sleeved with the air outlet pipe 72 by the connecting sleeve 74, and the water sealing cap 73 can be adjusted up and down along the air outlet pipe 72 along with the connecting sleeve 74. The frequency, interval and strength of the release of the large bubbles can be changed by adjusting the depth of the air outlet pipe 72 which is deep into the water seal cap 73.

Referring to fig. 3, the lower end of the connecting sleeve 74 extends into the water sealing cap 73, the connecting sleeve 74 is connected with the water sealing cap 73 through spokes 75, the connecting sleeve 74 is limited at the middle position of the water sealing cap 73 through the surrounding spokes 75, and a gap is left between the lower port of the connecting sleeve 74 and the bottom of the water sealing cap 73 for intermittent gas pulse discharge.

The connection sleeve 74 and the water sealing cap 73 may also be directly connected, for example, in some embodiments, the lower end of the connection sleeve 74 is directly connected with the bottom of the water sealing cap 73, and a through hole is provided on the lower end pipe wall of the connection sleeve 74 for the purpose of realizing the air flow.

According to the embodiment of the invention, the interface clapboard 6 is arranged, and the second aeration device 7 is arranged on the interface clapboard 6, so that the problem of sharing caused by the difference of aeration targets, purposes and control methods of the aerobic tank 4 and the membrane tank 3 is solved, the aeration energy consumption of the whole system is reduced, and the sweeping effect of the membrane module is ensured.

In some embodiments, referring to fig. 7 and 8, the membrane module 5 comprises a membrane frame 50 and a membrane module 52, the membrane module 52 is mounted on the membrane frame 50, the membrane module 52 comprises the membrane elements and a water collecting box for collecting produced water of the membrane elements, a water producing pipe 51 is connected with the water collecting box, the membrane module 5 enables the membrane module 5 to obtain the required buoyancy to float in the membrane pool 3 through the water discharging volume of the membrane frame 50, and the membrane elements are immersed in the membrane pool 3 when the membrane module 5 floats in the membrane pool 3. Wherein, the water production pipe 51 adopts a flexible pipe, which is convenient for the membrane module device 5 to swing in the membrane pool 3. The membrane module 5 has no membrane aeration line. The membrane group device 5 is connected with a water production main pipe only by a water production pipe 51, and the purposes of water production and online backwashing are realized. Because the large bubbles converted from the small bubbles of the aeration tail gas of the aerobic tank 4 are used for flushing the surface of the membrane, the bottom of the membrane component 52 in the invention does not need to be provided with a special aeration device unlike the traditional membrane component 5.

Wherein, the membrane element can adopt the cavity membrane silk, and the header box is connected at the both ends of cavity membrane silk, further is fixed in membrane frame 50 through the header box to produce water through the header box collection membrane silk, produce water pipe 51 and be connected with the header box, be used for seeing off the product water. Of course, flat sheet membranes can also be used as membrane elements.

The membrane module device 5 for installing the membrane module 52 is in a floating state in the membrane tank 3, is not fixedly connected with the tank body except that the water production pipe 51 and the aeration pipe (which can be omitted) are connected with the membrane module device, and is more convenient to install, disassemble and clean. Meanwhile, the membrane module 5 is not required to be fixed at the bottom of the membrane tank 3 or on the tank wall, but is in a state of swinging along with water flow, is similar to the membrane module 5 in non-aeration reciprocating motion, and can reduce the requirement on aeration by means of scouring shearing force of the water flow. Compared with the traditional membrane module 5 which is placed at the bottom of the membrane pool 3 or hung on the wall of the membrane pool 3, the membrane module 5 can simplify the components of the membrane filtration system, and is convenient to install, disassemble, operate, overhaul and manage.

In some embodiments, in order to generate sufficient buoyancy, the membrane module 5 further comprises a floating member mounted to the membrane frame 50, and the membrane module 5 makes the membrane module 5 obtain the buoyancy required for floating in the membrane tank 3 through the membrane frame 50 and the displacement volume of the floating member.

Further, referring to fig. 7, the floating member includes a float bowl 53 mounted on the top of the membrane frame 50, the float bowl 53 being secured above the membrane frame 50 by clips, and different buoyancy forces can be generated by changing the outer diameter and number of the float bowls 53.

Further, referring to fig. 8, the floating member includes a floating plate 54 installed at a side of the membrane frame 50, and the buoyancy generated may be changed by changing the thickness and height of the floating plate 54 and selecting different materials of the floating plate 54.

The immersion depth of the membrane module 5 in water can be adjusted, the distance between the top end of the membrane module 52 and the liquid surface can be set to be 0.1-0.5 m by adjusting the floating component, and the fixed immersion depth can be maintained during operation.

Introduction of operation conditions and processing effects of embodiments of the invention

General overview of the examples:

the raw water of the project is the effluent of a homogenizing tank of a certain Guangzhou industrial wastewater treatment plant, and the water quality fluctuation is large because the treatment capacity of high-concentration wastewater needs to be frequently changed in water plant production. The water quality characteristics are shown in Table 1, the COD/TN of the test sewage is 2.18-10.64, the average value is 5.7, the BOD5/COD is 0.04-0.36, and the average value is 0.20.

TABLE 1 Water quality characteristics for the test

The operating parameters adopted in this embodiment are:

TABLE 2 operating parameters Table

Referring to fig. 9-12, the treatment effect on COD, TN, ammonia nitrogen is significant and stable in this example, and the specific data are as follows: the COD of the inlet water is about 200-250 mg/L, and the COD of the outlet water is about 50mg/L in a stable operation period; the inlet water TN is 20-40 mg/L, and the outlet water TN is about 5-10 mg/L in a stable operation period; the ammonia nitrogen of the inlet water accounts for 20-40 mg/L, the ammonia nitrogen of the outlet water accounts for 54.5% of the ammonia nitrogen of less than 1.5mg/L, and the ammonia nitrogen of the outlet water accounts for 94% of the ammonia nitrogen of less than 5 mg/L.

Operating costs

In the embodiment of the invention, the water for the test is the water for the front end of the homogenizing pool, so that under normal conditions, a small amount of carbon source is not needed or only needs to be added, in the embodiment, no carbon source is added, and the alkalinity does not need to be adjusted, so that the cost of the running medicament is 0. The whole system only needs membrane cleaning agent to generate cost, which is about 0.01 yuan/ton water.

Stability of operation of membrane (flotation) system

Example 1: referring to FIG. 13, when the membrane flux is 18LMH, the air volume fluctuates from 5 Nm to 12Nm3/h, the sludge concentration is maintained between 11000 mg/L to 12000mg/L, and the change situation of the water permeability is shown in the following graph, the running water permeability is stable, and the attenuation rate is 0.18 LMH/bar.h.

Example 2: referring to FIG. 14, in the case that the membrane operating flux is 30LMH, the sludge concentration is 4000-14000 mg/L, and the air volume is 4-8 Nm3/h, the membrane system operates stably, and the attenuation rate of the water permeability is about 0.16 LMH/bar.h.

Examples 1 and 2 during the operation, the floating condition and the sludge collection condition of the floating membrane frame 50 are always kept good, and the water permeability of the membrane operation is always stable, which proves that the floating membrane frame 50 and the combined aeration system have technical feasibility.

Comparison of the embodiment of the invention with the conventional A/O MBR:

comparative example 1 (municipal or town sewage)

The main sources of energy consumption of the conventional membrane bioreactor 1 are: a biochemical process aeration blower, a membrane scrubbing aeration blower, a sludge reflux pump, a suction pump, a lifting pump and an anoxic zone stirrer. Wherein the process aeration of the biochemical pool accounts for 42 percent of the energy consumption of the whole system, the membrane system aeration accounts for 34 percent, the sludge backflow accounts for 10 percent, the suction pump and the lift pump account for 4 percent, the stirring of the anoxic zone accounts for 9 percent, and the other energy consumption is about 1 percent. Therefore, compared with the traditional A/O-MBR system, the biochemical tank process aeration of the embodiment of the invention accounts for less than 34% of the energy consumption of the whole system, the membrane system aeration accounts for 0%, the sludge reflux accounts for less than 10%, the suction pump and the lift pump account for 4%, the stirring in the anoxic zone accounts for 0%, and the other energy consumption accounts for about 1%. Therefore, the whole energy consumption of the novel A/O MBR is lower than 49% of the traditional energy consumption, namely, the energy consumption is saved by at least more than 50%.

TABLE 3 preliminary comparison of energy consumption of conventional A/O MBR and the present invention (municipal or town sewage)

Comparative example 2 (industrial waste water)

Compared with the traditional A/O MBR, the gas-water of the embodiment of the invention can save 74 percent, so that the energy consumption can be saved by at least 74 percent. In addition, the range of Dissolved Oxygen (DO) required by nitrification in the embodiment of the invention is very wide and can be as low as 0.1-0.4 mg/L, so that the proper level of the Dissolved Oxygen (DO) can be optimally selected according to the process requirements (emission standard), energy price and the like, and the purposes of high efficiency and low consumption operation are achieved.

TABLE 4 preliminary comparison of energy consumption for conventional A/O MBR and the inventive examples (Industrial wastewater)

Floor area comparison (evaluation by residence time of system)

The HRT of the embodiment of the invention is saved by 85.8 percent compared with the traditional A/O MBR, and the aerobic tank 4 and the membrane tank 3 of the embodiment of the invention are vertically arranged, so that the occupied area can be further reduced, and the initial investment can be saved.

TABLE 5 comparison of residence time for conventional A/O MBRs and examples of the present invention

And (3) processing capacity comparison:

the sludge load, the nitrification rate and the denitrification rate of the embodiment of the invention are 3.5-4.5 times of those of the traditional A/OMBR. As shown in the table below, the absolute value of contaminant removal for the inventive example is slightly better than for the conventional A/O MBR, both systems have been treated to the limit. But because the sludge concentration of the inventive example is high and the residence time of the system is short, the treatment capacity is far better than that of the traditional A/O MBR.

TABLE 6 comparison of throughput for conventional A/O MBRs and examples of the present invention

Comparison of effects before and after accurate control by adopting dissolved oxygen in the embodiment of the invention

By adopting the dissolved oxygen accurate control technology provided by the embodiment of the invention, the Dissolved Oxygen (DO) of the system can be ensured to be stable in real time, on one hand, the impact of the water quality or water quantity of the system can be well resisted, on the other hand, the air quantity of a fan can be adjusted in real time according to the requirement of the Dissolved Oxygen (DO) of the system, and the excessive aeration quantity of the traditional MBR is avoided. In addition, because the denitrification system is sensitive to Dissolved Oxygen (DO), the embodiment of the invention adopts a dissolved oxygen fine control technology, so that the removal effect of TN is more obvious and stable. The data are as follows:

TABLE 8 comparison of TN removal effect before and after the precise control technique of dissolved oxygen

Note: the traditional control mode means that the real-time automatic adjustment is not carried out according to the water inlet load and the water inlet quantity, and the Dissolved Oxygen (DO) of the system is possibly increased under the condition that the COD and the ammonia nitrogen of the inlet water are reduced or the water quantity is reduced; in the case that the COD and ammonia nitrogen of the inlet water become high or the water amount becomes large, the Dissolved Oxygen (DO) is possibly insufficient, so that the removal effect is not ideal, and therefore, the traditional A/OMBR Dissolved Oxygen (DO) control mode leaves a large margin and causes unnecessary waste. And the dissolved oxygen accurate control system is adopted to adjust the air quantity of the fan in real time according to the Dissolved Oxygen (DO) value of the system, so that the Dissolved Oxygen (DO) running of the system can be ensured to be more stable, the removal effect is better, and the consumption of energy consumption can be proper.

The embodiment of the invention has the beneficial effects that:

(1) the embodiment of the invention is a novel high-efficiency energy-saving process of integrated A/O MBR, which is designed by horizontally and vertically combining a tank body, combines the advantages of a floating membrane group device 5 and a combined aeration system, and can thoroughly solve three bottlenecks of high energy consumption, high cost and high design, construction and installation requirements, which limit the development of MBR at present. Compared with the traditional A/O MBR, the method has remarkable advantages in the aspects of processing capacity, energy consumption, occupied area, system operation stability, impact resistance, automation level and the like.

(2) The adopted floating membrane group device 5 solves the problems that the traditional MBR membrane frame 50 has high requirements on design and civil engineering construction, is difficult to install and fix, the membrane frame 50 floats upwards, membrane aeration is not uniform and the like, and is beneficial to daily operation and maintenance.

(3) The adopted floating membrane group device 5 is only flexibly connected with a water producing hose, is convenient to disassemble and assemble, is easy to adopt ectopic membrane recovery chemical cleaning, improves the chemical cleaning efficiency and saves cleaning agents.

(4) Because of adopting the combined aeration system, the membrane aerator does not need to be installed on the membrane group device 5, the sludge collection problem caused by the traditional membrane aerator installed at the bottom is thoroughly solved, an aeration pipe is not needed, and the design, the installation and the maintenance are simplified.

(5) The anoxic tank 2, the aerobic tank 4 and the membrane tank 3 are integrally designed, and form a horizontal and vertical combination in spatial arrangement to form an integrated three-zone, so that the space utilization rate is high, and the occupied area is small; the problems that the traditional MBR is an aerobic tank 4 and a membrane tank 3 which are horizontally arranged, the civil engineering structural design and construction are adversely affected, the occupied area is large and the like are solved.

(6) The aeration system of the aerobic tank 4 and the aeration system of the membrane tank 3 are simplified into a combined aeration system, and the defects of multiple devices, complex system, complex operation control, high operation energy consumption and the like caused by respective independence of the aeration system of the aerobic tank 4, the aeration system of the membrane tank 3 and a sludge reflux system in the traditional A/O MBR are overcome. The combined aeration system only needs one set of aeration system of the aerobic tank 4 as the power of activated sludge oxygen supply, membrane aeration and sludge backflow, and realizes 'one-gas-three-purpose'.

(7) The sludge forms a large circulation flow state among the anoxic tank 2, the aerobic tank 4 and the membrane tank 3, wherein the anoxic tank 2, the aerobic tank 4 and the membrane tank 3 are vertically arranged in a three-dimensional manner instead of being arranged horizontally, and theoretically, circulation can be formed by air stripping, so that low or no energy consumption self-refluxing is realized. And a water pump can be added to assist circulation to form an A/O MBR system, so that pollutant components such as COD, TN, ammonia nitrogen and the like can be efficiently removed.

(8) Compared with the traditional MBR process, the embodiment of the invention only needs one set of aeration system of the aerobic tank 4, simultaneously meets the requirements of biochemical oxygen supply, membrane aeration and 2-gas stirring of the anoxic tank and provides power for the backflow of sludge mixed liquid, and the system has the advantages of low integral operation Dissolved Oxygen (DO), obvious energy saving and consumption reduction, preliminary estimation, energy consumption saving of more than 50 percent and low operation cost.

(9) The air quantity of the fan is controlled in real time by adopting a dissolved oxygen accurate control technology, the automation degree is high, the impact resistance is strong, and the process operation is stable.

(10) The membrane operates stably under high flux and low Dissolved Oxygen (DO), and the water permeability attenuation rate of the membrane is low.

In the description herein, references to the description of the term "example," "an embodiment," or "some embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The invention is not limited to the above embodiments, and those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the invention, and such equivalent modifications or substitutions are included in the scope of the claims of the present application.

Claims (10)

1. The utility model provides a wastewater treatment system, its characterized in that, includes the reactor, the inside subregion baffle that is equipped with of reactor, the inner space of reactor in the front side of subregion baffle forms the oxygen deficiency pond, the inner space of reactor in the rear side of subregion baffle forms the membrane cisterna, the bottom of reactor in the below of membrane cisterna forms good oxygen pond, the oxygen deficiency pond with the lower part in good oxygen pond is linked together, be equipped with first aeration equipment in the good oxygen pond, membrane cisterna top periphery is equipped with the backward flow canal, mud mixed liquid in the membrane cisterna can turn over under the air stripping effect to the backward flow canal, the backward flow canal is equipped with and is connected to the oxygen deficiency return line in oxygen deficiency pond and is connected to the good oxygen return line in good oxygen pond, be equipped with the membrane group ware in the membrane cisterna, the membrane group ware is connected and is produced the water pipe.

2. The wastewater treatment system of claim 1, wherein the bottom end of the partition wall forms a dead center before extending to the bottom of the reactor, and the bottom end of the partition wall is provided with an inclined partition wall extending obliquely downward.

3. The wastewater treatment system according to claim 1, wherein an interface partition plate is arranged between the aerobic tank and the membrane tank, the interface partition plate is provided with a second aeration device, the second aeration device comprises a gas collection chamber and a gas outlet pipe, the gas collection chamber is opened downwards, the top end of the gas outlet pipe penetrates through the interface partition plate and is communicated with the membrane tank, the lower end of the gas outlet pipe extends downwards into the gas collection chamber from the top of the gas collection chamber, the lower end of the gas outlet pipe is provided with a water sealing cap with an upward opening, a flow passage for intermittently discharging gas in the gas collection chamber is defined between the water sealing cap and the gas outlet pipe, and the membrane group device is arranged at the top end of the gas outlet pipe.

4. The wastewater treatment system of claim 3, wherein the interface baffle separates the aerobic tank from the membrane tank, and the edge of the interface baffle is provided with a gas stripping channel for communicating the aerobic tank with the membrane tank.

5. The wastewater treatment system according to claim 3, wherein a surrounding plate is arranged at the bottom edge of the interface clapboard, the interface clapboard forms an inverted cavity through the surrounding plate, a plurality of partition plates are arranged inside the surrounding plate, the cavity is divided into a plurality of gas collecting cavities by the partition plates, and each gas collecting cavity is provided with an air outlet pipe and a water sealing cap.

6. The wastewater treatment system of claim 1, wherein the first aeration device comprises a micro-porous aeration device connected to a fan via a conduit.

7. The wastewater treatment system according to claim 3, wherein a connecting sleeve is arranged in the middle of the water sealing cap, the water sealing cap is sleeved with the air outlet pipe through the connecting sleeve, and the water sealing cap can be adjusted up and down along the air outlet pipe along with the connecting sleeve.

8. The wastewater treatment system according to claim 1, wherein the membrane module comprises a membrane frame and a membrane module, the membrane module is mounted on the membrane frame, the membrane module comprises a membrane element and a water collecting box for collecting produced water of the membrane element, the water producing pipe is connected with the water collecting box, the membrane module enables the membrane module to obtain buoyancy required for floating in a membrane pool through a water discharging volume of the membrane frame, and the membrane element is immersed in the membrane pool when the membrane module floats in the membrane pool.

9. The wastewater treatment system of claim 8, wherein the membrane module further comprises a floating member mounted to the membrane frame, the membrane module providing the membrane module with a desired buoyancy to float in the membrane basin by the displacement volume of the membrane frame and the floating member.

10. The wastewater treatment system of claim 9, wherein the floating member comprises a pontoon mounted on top of the membrane frame and/or a floating plate mounted on a side of the membrane frame.

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