Double-membrane water purification treatment system integrating air floatation and precipitation

Abstract

The invention belongs to the technical field of sewage treatment, and relates to a double-membrane water purification treatment system integrating air floatation and precipitation. The aeration and filler system comprises a tubular silicon carbide film, air is fed into the top end of the silicon carbide film, air is discharged in the circumferential direction of the silicon carbide film to form an aeration system, and a biological film is attached to the silicon carbide film to form a filler system; an overflow weir for discharging purified water is arranged at the top of the tank body; nanobubbles formed by the aeration system serve as carriers to be attached to the light sludge, and the light sludge is driven to float upwards and discharged out of a sludge discharging groove in the top of the tank body; a sludge bucket is arranged at the bottom of the tank body, the sludge bucket is located under the aeration and filling system, and heavy sludge is collected in the sludge bucket to be discharged after being settled. The double-membrane water purification treatment system integrating air floatation and precipitation, provided by the invention, has the air floatation system, the aeration system and the filler system, and improves the sewage treatment effect.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment and relates to a double-membrane water purification system for collecting air flotation and sedimentation. Background Art

[0002] The conventional biological contact oxidation wastewater treatment system is as follows Figure 1 As shown, it includes an aerobic pool (1-1), an aeration system, a filler system, and a drainage system. Pretreated sewage enters the pool body, and the pollutants in the sewage are adsorbed and digested by the bacteria on the filler (1-2) to achieve the purpose of water purification. The purified water is discharged through the drain (1-3), and the discharged water needs to be separated from mud and water. The filler system generally includes fillers (1-2) and filler brackets (1-4). The fillers (1-2) are generally soft, semi-soft, and elastic, which can increase the shaking intensity, shake off the aged bacteria on the fillers (1-2), and keep the bacteria updated. The aeration system in the pool generally includes an aeration main pipe (1-5) and an air distribution pipe (1-6) connected thereto. The aeration system is designed to provide oxygen for the bacteria and to shake the fillers (1-2) to update the bacteria.

[0003] The sewage treatment system of the traditional biological contact oxidation method has many defects. Specifically, 1. System defects: Two systems need to be set up in the aerobic pool, the aeration and air distribution system and the filler system. The aging and shedding of the filler is easy to block the air distribution system. The role of aeration is to vibrate the filler to ensure the sludge shedding and renewal and provide dissolved oxygen. In order to ensure strong vibration, the bubbles generated by the aeration system are large, and the dissolved oxygen efficiency is limited, which can only reach about 20% at most. In addition, the treated water is mixed with aged sludge, and further mud and water separation is required. 2. Filler defects: The filler is generally made of aldehyded fiber or polyester yarn or polymer or polyolefin and polyamide materials, with a small specific surface area, hydrophobic material, and slow film formation. The filler is immersed in the pool for a long time, which is easy to harden and degenerate, and the quality is reduced, and it needs to be replaced regularly. Microplastics will be generated under the scouring and friction of the filler, which will increase the microplastic pollution of environmental water resources. Due to the use of flexible fillers, the filler is easy to fall off during long-term shaking, and the processing capacity will deteriorate after falling off, and the pipes and air distribution system will be blocked. Moreover, it is troublesome to replace the filler, and the pool body needs to be emptied for cleaning. When running again, the film needs to be attached again, and the recovery time is long.

[0004] In order to improve the shortcomings of the traditional biological contact oxidation method, Chinese invention patent application CN105923751A (publication date: 2016.09.07) discloses a ceramic membrane and an aerated membrane bioreactor installed with the ceramic membrane, wherein the ceramic membrane includes a ceramic membrane support and a separation layer attached to the ceramic membrane support, wherein: the preparation of the ceramic membrane support includes: mixing and stirring 42% of the ceramic membrane support powder, 2% of the pore-forming agent, 1% of the binder and 55% of the sintering aid by mass percentage, and sintering at a temperature of 960°C for 8h to obtain the ceramic membrane support; coating the film-forming liquid for forming the separation layer on the inner surface of the ceramic membrane support until the surface is uniform, and sintering the dried ceramic membrane coated with the film-forming liquid for forming the separation layer at 800°C to obtain the ceramic membrane support with the separation layer attached; the reactor has the functions of a membrane bioreactor, an aerated membrane bioreactor and a biofilm reactor.

[0005] However, in actual use, it was found that the ceramic membrane was prone to clogging, the perforated tube aeration efficiency was low, and the biofilm was unevenly flushed (the top of the ceramic membrane could not be flushed). These problems greatly reduced the water treatment effect. At the same time, it was necessary to arrange a system outside the double-membrane water treatment system to further separate the light sludge. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a double-membrane water purification system integrating air flotation and sedimentation, which has an air flotation system, an aeration system and a filler system, thereby improving the sewage treatment effect.

[0007] In order to solve the above technical problems, the purpose of the present invention is achieved through the following technical solutions:

[0008] A double-membrane water purification system combining air flotation and sedimentation, comprising:

[0009] Pool body;

[0010] An aeration and filler system, comprising a tubular silicon carbide membrane, wherein air is introduced into the top of the silicon carbide membrane and exhausted in the circumferential direction to form an aeration system, and a biofilm is attached to the silicon carbide membrane to form a filler system;

[0011] Drainage system, the top of the tank is provided with an overflow weir for discharging purified water;

[0012] The flotation system, wherein the nanobubbles formed by the aeration system act as carriers and adhere to the light sludge, driving the light sludge to float and be discharged from the sludge discharge trough at the top of the tank body;

[0013] Mud discharge system: a mud hopper is provided at the bottom of the tank body, and the mud hopper is located directly below the aeration and filler system. After the heavy sludge settles, it is collected in the mud hopper and discharged;

[0014] The overflow weir and the mud discharge trough are distributed on opposite sides of the pool body. A mud scraper is arranged on the top of the pool body. The scraper of the mud scraper moves from the side where the overflow weir is located to the side where the mud discharge trough is located to skim off the floating mud.

[0015] In the above-mentioned double-membrane water purification system with air flotation and sedimentation, the aeration and filling system is provided with multiple groups, each group of aeration and filling system is connected to the air intake branch pipe respectively, and the air intake branch pipe is connected to the air intake main pipe, and the air intake main pipe and / or the air intake branch pipe are provided with a proportional valve for controlling the air intake volume.

[0016] In the above-mentioned double-membrane water purification system with air flotation and sedimentation, the aeration and filler system is accommodated in a frame, the air intake main pipe and the air intake branch pipe are detachably connected through flanges, and the frame can be lifted out of the tank body after disassembly.

[0017] In the above-mentioned double-membrane water purification system combining air flotation and sedimentation, the scraper of the sludge scraper is driven by a power device, and the power device is selected from an electric telescopic rod or a combination of a motor and a transmission system.

[0018] In the above-mentioned double-membrane water purification system for collecting air flotation and sedimentation, the axis of the silicon carbide membrane is arranged vertically and distributed in an array, the silicon carbide membrane includes an inner membrane layer and a support layer, and a central air hole is formed in the tube, the upper end of the central air hole is an air inlet, and the lower end is reserved for washing holes for flushing mud buckets. When multiple groups of aeration and filling systems are provided, each group of aeration and filling systems corresponds to a group of mud buckets. The washing holes can be controlled by valves, and the valves are opened when flushing is required, and the valves are normally closed.

[0019] In the above-mentioned double-membrane water purification system with gas flotation and sedimentation, the washing hole can also use other structures: the gas branch pipe is connected to a flushing pipe extending to the bottom of the mud bucket, and a washing hole is formed at the end of the flushing pipe. The flushing pipe is controlled by a valve, and the valve is opened when flushing is required, and the valve is normally closed.

[0020] In the above-mentioned double-membrane water purification system integrating air flotation and sedimentation, the pore size of the silicon carbide membrane is 10-100nm, the membrane thickness is 10-100μm, the porosity of the support layer is above 40%, and the bacteria forming the biofilm reproduce in the inner pores of the support layer and the outer surface of the silicon carbide membrane; preferably, the porosity of the support layer is above 45%.

[0021] In the above-mentioned double-membrane water purification system with air flotation and sedimentation, a three-effect separator is arranged on the overflow weir side of the pool body, and a baffle is arranged above the three-effect separator. The upper edge height of the baffle is higher than the overflow height of the overflow weir, and the scraper of the scraper moves from the inside of the baffle toward the mud discharge trough.

[0022] In the above-mentioned double-membrane water purification system for collecting air flotation and sedimentation, a mud guide plate is arranged inside the mud discharge groove, and the mud guide plate is arranged to be inclined downward from the upper edge of the mud discharge groove.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides a double-membrane water purification system integrating flotation and sedimentation, which uses a silicon carbide membrane attached to a biofilm as a filler, combines the aeration system and the filler system into one, and the nanobubbles generated by the silicon carbide can also serve as a carrier of the flotation system, and cooperate with other structures of the flotation system to separate and discharge light sludge. Therefore, the water treatment system of the present invention has a flotation system, an aeration system and a filler system, does not require an additional flotation sedimentation tank, and has the advantages of small footprint, low investment, and low operating energy consumption.

[0025] 2. The present invention sets a concave mud bucket structure at the bottom of the pool body for collecting heavy sludge, so as to facilitate the discharge of the sludge that sinks to the bottom of the pool. At the same time, the present invention also sets a corresponding air washing hole structure on the aeration and filler system, and the air washing hole can be used to spray gas to the mud bucket, and the mud in the mud bucket is ensured not to be compacted by flushing the mud bucket, and the discharge of the sludge can also be accelerated.

[0026] 3. The present invention can improve the sewage treatment effect. ① When the gas passes through the inner membrane layer of the silicon carbide membrane, it is cut into nano-scale bubbles, which have a high oxygen transfer rate and high oxygen utilization rate; ② The silicon carbide membrane is hydrophilic and has a large specific surface area, which is conducive to the growth and reproduction of bacteria and the increase of biofilm; moreover, the silicon carbide membrane tube has a large filling density, and a larger specific surface area can be formed per unit pool capacity; ③ The double membrane treatment process is adopted, combined with flotation and sedimentation, and the effluent water quality is better than the existing biological contact oxidation method; ④ The gas speed in the silicon carbide membrane is fast, and the bacterial mass on the membrane wall can be properly flushed to ensure the renewal of the bacterial species; ⑤ There is no need to disturb the pool water to vibrate the filler, which can reduce the amount of aeration, the bubbles have less disturbance to the pool water, and the heavy sludge is also easier to sink to the bottom of the pool.

[0027] 4. The present invention is highly environmentally friendly. ① Silicon carbide filler is used, which can be restored and regenerated without replacement, which is economical and environmentally friendly; ② Traditional fillers are vibrated and washed to precipitate microplastics, while silicon carbide is an inorganic material and does not pollute microplastics; ③ The cost of scrapping traditional fillers is high and will cause secondary environmental pollution, while silicon carbide can be recycled and is an inorganic material and does not pollute the environment.

[0028] 5. The present invention further provides a triple-effect separator, and deeply integrates it with the drainage system, the flotation system and the mud discharge system. The light sludge and the heavy sludge are separated by the triple-effect separator. The light sludge floats up under the influence of the flotation system and is discharged through the scraper and the mud discharge trough, and the heavy sludge sinks and is discharged through the mud hopper. In addition, the use of a baffle can prevent the light sludge separated by the triple-effect separator from being discharged with the purified water from the overflow weir. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the sewage treatment system using the traditional biological contact oxidation method;

[0030] Figure 2 It is a structural schematic diagram of the double membrane water purification system of the present invention;

[0031] Figure 3 is a schematic structural diagram of a silicon carbide film of the present invention;

[0032] Reference numerals:

[0033] Figure 1 :1-1, aerobic tank; 1-2, filler; 1-3, drain outlet; 1-4, filler support; 1-5, aeration main pipe; 1-6, air distribution pipe;

[0034] Figure 2 and Figure 3 : 1. Pool body; 2. Silicon carbide membrane; 3. Overflow weir; 4. Mud discharge trough; 5. Mud bucket; 6. Mud scraper; 7. Air inlet branch pipe; 8. Air inlet main pipe; 9. Proportional valve; 10. Frame; 11. Flange; 12. Three-effect separator; 13. Baffle; 14. Mud guide plate; 21. Inner membrane layer; 22. Support layer; 23. Central air hole; 24. Air inlet hole; 25. Air washing hole. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to specific embodiments of the present invention. Figure 2-3 :

[0036] A double-membrane water purification system combining air flotation and sedimentation, comprising:

[0037] A tank body 1, wherein the tank body 1 is used to introduce sewage to be purified;

[0038] The aeration and filling system includes a tubular silicon carbide membrane 2, wherein air is introduced at the top of the silicon carbide membrane 2 and exhausted in the circumferential direction to form an aeration system, and a biofilm is attached to the silicon carbide membrane 2 to form a filling system. When sewage is introduced, the silicon carbide membrane 2 and the biofilm adsorb and filter pollutants in the sewage, and degrade the pollutants through bacteria to purify the sewage and form purified water. At the same time, the gas passes through the silicon carbide membrane 2 to generate nano-bubbles or bubble-free aeration to provide dissolved oxygen required by the bacteria.

[0039] Drainage system: an overflow weir 3 for discharging purified water is provided on the top of the tank body 1;

[0040] Air flotation system: When the gas passes through the silicon carbide membrane 2, it is cut into nano-scale bubbles. The nano-bubbles formed by the aeration system act as carriers and attach to the light sludge (including suspended solids SS), driving the light sludge to float, eventually float to the surface, and be discharged from the sludge discharge trough 4 at the top of the tank body 1;

[0041] Mud discharge system: a mud hopper 5 is provided at the bottom of the tank body 1, and the mud hopper 5 is located directly below the aeration and filler system. Heavy sludge (including suspended solids SS) and sludge falling off the aeration and filler system are collected in the mud hopper 5 and discharged after sedimentation;

[0042] The overflow weir 3 and the mud discharge trough 4 are distributed on opposite sides of the pool body 1. A mud scraper 6 is arranged on the top of the pool body 1. The scraper of the mud scraper 6 moves from the side where the overflow weir 3 is located to the side where the mud discharge trough 4 is located to skim off the floating mud. The scraper of the mud scraper 6 is driven by a power device, and the power device is selected from an electric telescopic rod or a combination of a motor and a transmission system. During the movement of the scraper, the floating mud on the water surface is driven to move toward the mud discharge trough 4, and finally enters the mud discharge trough 4 for discharge.

[0043] In this embodiment, the aeration and filling system is provided with multiple groups, each group of aeration and filling system is connected to the air intake branch pipe 7, and the air intake branch pipe 7 is connected to the air intake main pipe 8. The air intake main pipe 8 and / or the air intake branch pipe 7 are provided with a proportional valve 9 for controlling the air intake amount. By controlling the gas amount through the proportional valve 9, the flushing intensity and dissolved oxygen can be controlled, and the sludge amount can also be controlled, so as to achieve the purpose of seasonal and emergency adjustment of the processing capacity.

[0044] The aeration and filler system is accommodated in the frame 10, and the air intake main pipe 8 and the air intake branch pipe 7 are detachably connected by the flange 11. After the detachment, the frame 10 can be lifted out of the tank body 1. The design of lifting by removing the flange 11 is convenient for maintenance and replacement without emptying the tank body 1. When necessary, the silicon carbide membrane 2 can be lifted out for regeneration, and when the membrane pores are blocked, the performance can be restored by chemical washing and high-temperature incineration.

[0045] The axis of the silicon carbide membrane 2 is arranged vertically and distributed in an array. The silicon carbide membrane 2 includes an inner membrane layer 21 and a support layer 22, and a central air hole 23 is formed in the tube. The upper end of the central air hole 23 is an air inlet 24, and the lower end is left with a wash hole 25 for flushing the mud bucket 5. When there are multiple groups of aeration and filling systems, each group of aeration and filling systems corresponds to a group of mud buckets 5. A part of the gas entering the central air hole 23 acts on the mud bucket 5 through the wash hole 25, thereby flushing the mud bucket 5. The wash hole 25 can be controlled by a valve. When flushing is required, the valve is opened, and the valve is normally closed.

[0046] The pore size of the silicon carbide membrane 2 is 10-100nm, the membrane thickness is 10-100μm, the porosity of the support layer 22 is above 40%, and the bacteria forming the biofilm reproduce in the inner pores of the support layer 22 and the outer surface of the silicon carbide membrane 2. Preferably, the porosity of the support layer 22 is above 40%.

[0047] In order to further improve the sewage treatment effect, a triple-effect separator 12 is provided on the overflow weir 3 side in the tank body 1, and a baffle 13 is provided above the triple-effect separator 12. The upper edge height of the baffle 13 is higher than the overflow height of the overflow weir 3, and the scraper of the scraper 6 moves from the inner side of the baffle 13 to the mud discharge trough 4. The triple-effect separator 12 can further treat the sewage. When the sewage enters the tank body 1 near the overflow weir 3 after being treated by the flotation system, aeration and filler system, the triple-effect separator 12 further treats the purified water to separate light sludge and heavy sludge to improve the purification effect. By providing the baffle 13, the light sludge and other floating sludge separated by the triple-effect separator 12 can be prevented from being discharged from the overflow weir 3 with the purified water.

[0048] A mud guide plate 14 is provided inside the mud discharge groove 4, and the mud guide plate 14 is inclined downward from the upper edge of the mud discharge groove 4. By providing the mud guide plate 14, the mud scraper 6 can push the floating mud at the lower layer of the water surface into the mud guide groove along the inclined surface of the mud guide plate 14 when working, so as to improve the mud scraping efficiency.

[0049] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A double membrane water purification system combining air flotation and sedimentation, characterized in that: include: pool(1); An aeration and filler system comprises a tubular silicon carbide membrane (2), wherein air is introduced at the top of the silicon carbide membrane (2) and exhausted in the circumferential direction to form an aeration system, and a biological film is attached to the silicon carbide membrane (2) to form a filler system; A drainage system, wherein the top of the tank body (1) is provided with an overflow weir (3) for discharging purified water; An air flotation system, wherein the nanobubbles formed by the aeration system act as carriers and adhere to the light sludge, driving the light sludge to float and be discharged from the sludge discharge trough (4) at the top of the tank body (1); A sludge discharge system, wherein a sludge hopper (5) is provided at the bottom of the tank body (1), and the sludge hopper (5) is located directly below the aeration and filler system, and heavy sludge is collected in the sludge hopper (5) after sedimentation and discharged; The overflow weir (3) and the mud discharge trough (4) are distributed on two opposite sides of the pool body (1). A mud scraper (6) is provided on the top of the pool body (1). The scraper of the mud scraper (6) moves from the side where the overflow weir (3) is located to the side where the mud discharge trough (4) is located to skim off the floating mud.

2. A double membrane water purification system combining air flotation and sedimentation according to claim 1, characterized in that: The aeration and filling system is provided in multiple groups, each group of the aeration and filling system is connected to an air intake branch pipe (7), each of the air intake branch pipes (7) is connected to an air intake main pipe (8), and a proportional valve (9) for controlling air intake volume is provided on the air intake main pipe (8) and / or the air intake branch pipe (7).

3. A double membrane water purification system combining air flotation and sedimentation according to claim 2, characterized in that: The aeration and filling system is accommodated in a frame (10), and the air intake main pipe (8) and the air intake branch pipe (7) are detachably connected via a flange (11).

4. A double membrane water purification system combining air flotation and sedimentation according to claim 1, characterized in that: The axis of the silicon carbide membrane (2) is arranged vertically and distributed in an array. The silicon carbide membrane (2) comprises an inner membrane layer (21) and a support layer (22). A central air hole (23) is formed in the tube. The upper end of the central air hole (23) is an air inlet hole (24), and the lower end is provided with a wash hole (25) for flushing the mud bucket (5). When multiple groups of aeration and filling systems are provided, each group of aeration and filling systems corresponds to a group of mud buckets (5).

5. A double membrane water purification system combining air flotation and sedimentation according to claim 4, characterized in that: The pore size of the silicon carbide membrane (2) is 10-100 nm, the membrane thickness is 10-100 μm, the porosity of the support layer (22) is above 40%, and the bacteria that form the biofilm reproduce in the internal pores of the support layer (22) and the outer surface of the silicon carbide membrane (2).

6. A double membrane water purification system combining air flotation and sedimentation according to claim 1, characterized in that: A three-effect separator (12) is arranged on the side of the overflow weir (3) in the tank body (1), and a baffle (13) is arranged above the three-effect separator (12). The upper edge height of the baffle (13) is higher than the overflow height of the overflow weir (3), and the scraper of the scraper (6) moves from the inner side of the baffle (13) toward the mud discharge trough (4).

7. A double membrane water purification system combining air flotation and sedimentation according to claim 1, characterized in that: A mud guide plate (14) is arranged inside the mud discharge groove (4), and the mud guide plate (14) is arranged to be inclined downward from the upper edge of the mud discharge groove (4).

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