An urban reclaimed water treatment system based on submerged ultrafiltration

Abstract

The invention discloses an urban recycled water treatment system based on submerged ultrafiltration, which comprises: a water inlet pipe for connecting to a water pipe of a sewage treatment plant, one end of the water inlet pipe being connected to a biological aeration filter, an submerged ultrafiltration device being arranged outside the biological aeration filter, and capable of filtering and intercepting SS and undecomposed small-molecule organic matter; a mixed ion exchanger being arranged outside the biological aeration filter, a drainage end of the submerged ultrafiltration device being connected to the mixed ion exchanger, a reverse osmosis device being arranged outside the submerged ultrafiltration device, and SS and undecomposed small-molecule organic matter intercepted in the submerged ultrafiltration device being able to enter the reverse osmosis device through a pipeline; a primary desalination device being connected outside the reverse osmosis device, and both the primary desalination device and the mixed ion exchanger being provided with drainage pipes; and a desalted water tank being further connected outside the mixed ion exchanger.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycled water treatment equipment, and in particular is an urban recycled water treatment system based on immersion ultrafiltration. Background Art

[0002] The main task of the boiler feed water treatment system in a thermal power plant is to provide sufficient desalted water of qualified quality. Generally, the water source of the boiler feed water treatment system is groundwater or surface water with good water quality. Water-scarce areas generally use municipal tap water. With the application and development of ultrafiltration membrane treatment technology in the field of water treatment, urban recycled water is used as the water source of the boiler feed water treatment system, providing a reference for the application of urban recycled water in the power industry. In the prior art, after the recycled water enters the membrane pool, it is filtered using an ultrafiltration membrane. The sludge that is difficult to filter easily adheres to the surface of the ultrafiltration membrane, thereby reducing the flux of the ultrafiltration membrane and affecting the filtration speed. Although the single multi-pump booster drainage can increase the reclaimed water pumping pressure, it will cause the attached sludge to penetrate through the pores of the ultrafiltration membrane, affecting the water quality. The regular decontamination and cleaning is labor-intensive and will affect the reclaimed water treatment process. Therefore, those skilled in the art provide an urban recycled water treatment system based on immersion ultrafiltration to solve the problems raised in the above background technology. Summary of the Invention

[0003] To achieve the above objectives, the present invention provides the following technical solution: an urban recycled water treatment system based on submerged ultrafiltration, comprising: an inlet pipe for connecting to a water pipe from a sewage treatment plant, one end of the inlet pipe being connected to a biological aeration filter, an submerged ultrafiltration device being disposed outside the biological aeration filter, the submerged ultrafiltration device being capable of filtering and intercepting SS and undecomposed small organic molecules;

[0004] A mixed ion exchanger is provided outside the biological aeration filter, the drainage end of the submerged ultrafiltration device is connected to the mixed ion exchanger, and a reverse osmosis device is provided outside the submerged ultrafiltration device, so that the SS and small molecular organic matter that are not decomposed in the submerged ultrafiltration device can enter the reverse osmosis device through a pipeline;

[0005] The reverse osmosis device is externally connected to a primary desalination device, and both the primary desalination device and the mixed ion exchanger are provided with drainage pipes, and the residual water treated in the primary desalination device can enter the mixed ion exchanger through a transfer pipe; the mixed ion exchanger is also externally connected to a desalination water tank.

[0006] Further, as a preference, the submerged ultrafiltration device includes: a temporary storage tank, which is connected to the aerated biological filter tank, two ultrafiltration membrane mechanisms are fixed overhead in the temporary storage tank, a flow tank is provided on one side of the temporary storage tank, a drainage assembly is fixed in the flow tank, a water pump is installed on the ultrafiltration membrane mechanism, the water pump is connected to each of the ultrafiltration membrane mechanisms through a branch pipe, and an external pipe is provided at the discharge port of the water pump to connect with the drainage assembly.

[0007] Furthermore, preferably, a circulation pipe is connected to the drainage component, a circulation pump is installed on the flow pool, one end of the circulation pipe is connected to the circulation pump, a plurality of diversion pipes are connected to the circulation pump, and one end of each diversion pipe is connected to the ultrafiltration membrane mechanism.

[0008] Further, as a preference, the drainage assembly includes: a flowing water tank, an end cover is fixed at the upper end thereof, a flow channel is provided on the end cover, the external pipe is connected to the flow channel, a membrane grid is fixed in the flowing water tank, and a negative pressure pipe is provided in the middle of the lower end face of the flowing water tank, the negative pressure pipe is connected to the membrane grid, and the circulation pipe is connected to one side of the lower end face of the flowing water tank.

[0009] Further, as a preference, the two ultrafiltration membrane mechanisms have the same composition structure, and the ultrafiltration membrane mechanism includes: an outer frame rod, which is suspended and fixed in the temporary storage pool, an adjustment seat is slidably provided on the outer frame rod, and a plurality of connecting pipes are vertically arranged below the adjustment seat, a confluence bin is installed on the adjustment seat, one end of the connecting pipe is connected to the confluence bin, a membrane tube is vertically provided in the connecting pipe, and an ultrafiltration membrane inner tube is also provided in the membrane tube, and sealing rings are provided between the connecting pipe, the membrane tube and the ultrafiltration membrane inner tube.

[0010] Furthermore, as a preference, the connecting pipes in the two ultrafiltration membrane mechanisms can be installed at different heights under vertical adjustment of the adjustment seat.

[0011] Furthermore, preferably, the plurality of diverter tubes are fixed on the outer frame rod, and one end thereof slides and extends into the membrane tube in the connecting tube, the lengths of each diverter tube extending into the membrane tube are different, and a baffle is fixed on the diverter tube by a support rod, and a drainage gap is left between the baffle and the inner wall of the membrane tube.

[0012] Furthermore, preferably, there are two inner ultrafiltration membrane tubes provided on the left and right, and a concave notch is provided on the tube wall of the membrane tube to form a filter residue retention recess.

[0013] Furthermore, preferably, a drainage bin is provided below the temporary storage tank, a stirring blade is rotatably provided in the drainage bin, and an extension path is provided in the drainage bin along the tangential direction of the rotation of the stirring blade, and a grille device is provided on the extension path.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention focuses on the use of urban recycled water as a source of boiler feed water. It studies a new aerated biological filter process combined with submerged ultrafiltration, reverse osmosis and other membrane treatment technologies to realize the use of urban recycled water as a water source for power plant boiler replenishment, heating network replenishment water, etc. The unique aerated biological filter is used to reduce the organic matter content in the reclaimed water, so that the production process system can operate safely and stably. Traditional reclaimed water treatment systems will cause system paralysis when the water quality deteriorates. The deep purification process using urban recycled water as boiler feed water can ensure water safety for a certain period of time, leaving time for abnormal handling. The aerated biological filter process simultaneously removes SS (suspended solids) solids, refers to the concentration of solids suspended in water), COD (refers to the amount of oxidants consumed by chemical oxidants to oxidize reducing substances in sewage), BOD (refers to the amount of dissolved oxygen consumed by microorganisms to oxidize reducing substances in sewage through biochemical reactions), and simultaneously achieves denitrification and dephosphorization, with the advantages of simple process, high organic load, small footprint, low investment, and good effluent quality; the submerged hollow fiber ultrafiltration membrane technology has a membrane pore size of only 0.1um, and has a good effect in removing impurities such as suspended matter and colloids, with high effluent indicators; the submerged ultrafiltration device also provided can ensure the ultrafiltration effect based on the continuous circulation of water, while avoiding the adhesion of filter residue and the blockage of the ultrafiltration membrane mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 Schematic diagram of the structure of the submerged ultrafiltration device of the present invention;

[0018] Figure 3 Schematic diagram of the structure of the circulation pump in the present invention;

[0019] Figure 4 It is a structural schematic diagram of the drainage component in the present invention;

[0020] Figure 5 Schematic diagram of the structure of the ultrafiltration membrane mechanism of the present invention;

[0021] Figure 6 Schematic diagram of the structure of the spoiler in the present invention;

[0022] Figure 7 Schematic diagram of the structure of the membrane tube in the present invention;

[0023] Figure 8 Schematic diagram of the structure of the drainage bin in the present invention;

[0024] In the figure: 1. Aerated biological filter; 11. Reverse osmosis device; 12. Desalted water tank; 13. Primary desalination equipment; 14. Mixed ion exchanger; 2. Immersed ultrafiltration device; 21. Temporary storage tank; 22. Flow tank; 23. Suction pump; 24. External pipe; 25. Circulation pipe; 26. Circulation pump; 27. Diverter pipe; 3. Ultrafiltration membrane mechanism; 31. External frame rod; 32. Adjustment seat; 33. Confluence chamber; 34. Connecting pipe; 35. Membrane tube; 36. Sealing ring; 37. Ultrafiltration membrane inner tube; 4. Drainage assembly; 41. Flow tank; 42. Flow channel; 43. Membrane grid; 44. Negative pressure pipe; 5. Support rod; 51. Baffle plate; 6. Drainage chamber; 61. Stirring blade; 62. Extension channel; 63. Grille device. DETAILED DESCRIPTION

[0025] See also Figure 1-8 In an embodiment of the present invention, an urban recycled water treatment system based on submerged ultrafiltration includes: an inlet pipe for connecting to a water pipe from a sewage treatment plant, one end of the inlet pipe being connected to a biological aeration filter 1, an submerged ultrafiltration device 2 being provided outside the biological aeration filter 1, the submerged ultrafiltration device 2 being capable of filtering and intercepting SS and undecomposed small molecular organic matter;

[0026] A mixed ion exchanger 14 is provided outside the biological aeration filter 1. The drainage end of the submerged ultrafiltration device 2 is connected to the mixed ion exchanger 14. A reverse osmosis device 11 is provided outside the submerged ultrafiltration device 2. The SS and small organic molecules that are not decomposed in the submerged ultrafiltration device 2 can enter the reverse osmosis device 11 through a pipeline. The biological aeration filter process has the functions of removing SS, COD, BOD, nitrification, denitrification, and phosphorus removal. The biological aeration filter is a new process that integrates biological oxidation and suspended solids interception. Compared with the ordinary activated sludge method, it has the advantages of simple process, high organic load, small footprint, low investment, no sludge swelling, high oxygen transfer efficiency, and good effluent water quality.

[0027] The reverse osmosis device 11 is externally connected to a primary desalination device 13, and both the primary desalination device 13 and the mixed ion exchanger 14 are provided with drainage pipes, and the residual water treated in the primary desalination device 13 can enter the mixed ion exchanger 14 through a transfer pipe; the mixed ion exchanger 14 is also externally connected to a desalination water tank 12. Through the research on aeration biological filter process combined with submerged ultrafiltration, reverse osmosis and other membrane treatment technologies, a new process of boiler feed water treatment system using aeration biological filter + submerged ultrafiltration + reverse osmosis (pre-desalination) + primary desalination + mixed bed treatment is obtained.

[0028] In this embodiment, the submerged ultrafiltration device 2 includes: a temporary storage tank 21, which is connected to the aerated biological filter 1, and two ultrafiltration membrane mechanisms 3 are fixed overhead in the temporary storage tank 21. A flow tank 22 is provided on one side of the temporary storage tank 21, and a drainage component 4 is fixed in the flow tank 22. A water pump 23 is installed on the ultrafiltration membrane mechanism 3, and the water pump 23 is connected to each of the ultrafiltration membrane mechanisms 3 through a branch pipe. An external pipe 24 is provided at the discharge port of the water pump 23 and is connected to the drainage component 4; wherein, the water that has completed ultrafiltration in the flow pool can be directly transported to the mixed ion exchanger.

[0029] As a preferred embodiment, the drainage component 4 is also connected to a circulation pipe 25, and a circulation pump 26 is installed on the flow pool 22. One end of the circulation pipe 25 is connected to the circulation pump 26, and the circulation pump 26 is connected to a plurality of shunt pipes 27. One end of each shunt pipe 27 is connected to the ultrafiltration membrane mechanism 3. Especially for the recycled water ultrafiltration process, the ultrafiltration membrane mechanism and the drainage component in this device can form a water circulation system through the circulation pipe and the external pipe, and the ultrafiltration treatment is continuously performed on it under the action of water circulation. On the one hand, the ultrafiltration effect is guaranteed and the water quality is improved. On the other hand, the filter residue is avoided from accumulating in the ultrafiltration membrane mechanism, resulting in a small amount of drainage in the ultrafiltration membrane mechanism. Compared with the traditional single increase in the number of water pumps, the submerged ultrafiltration device in the present invention can maintain the ultrafiltration water quality and stabilize the water flow rate.

[0030] In this embodiment, the drainage component 4 includes: a flowing water tank 41, an end cover is fixed at the upper end thereof, a flow channel 42 is provided on the end cover, the external pipe 24 is connected to the flow channel 42, a membrane grid 43 is fixed in the flowing water tank 41, and a negative pressure pipe 44 is provided in the middle of the lower end face of the flowing water tank 41, the negative pressure pipe 44 is connected to the membrane grid 43, and the circulation pipe 25 is connected to one side of the lower end face of the flowing water tank 41, wherein the negative pressure pipe transports the recycled water in the flowing water tank to the flow pool after re-ultrafiltration by the membrane grid under negative pressure pumping, with strong filtration effect and obvious improvement in water quality.

[0031] In this embodiment, the two ultrafiltration membrane mechanisms 3 have the same composition structure, and the ultrafiltration membrane mechanism 3 includes: an outer frame rod 31, which is overhead and fixed in the temporary storage tank 21, and an adjustment seat 32 is slidably provided on the outer frame rod 31, and a plurality of connecting pipes 34 are vertically arranged below the adjusting seat 32. A confluence bin 33 is installed on the adjusting seat 32, and one end of the connecting pipe 34 is connected to the confluence bin 33. A membrane tube 35 is vertically provided in the connecting pipe 34, and an ultrafiltration membrane inner tube 37 is also provided in the membrane tube 35. A sealing ring 36 is provided between the connecting pipe 34, the membrane tube 35 and the ultrafiltration membrane inner tube 37, that is, the regenerated water in the connecting pipe can be filtered by the membrane tube and the ultrafiltration membrane inner tube to achieve SS retention, and the regenerated water after ultrafiltration enters the confluence bin and is pumped by a water pump.

[0032] In this embodiment, the connecting pipes 34 in the two ultrafiltration membrane mechanisms 3 can be installed at different heights under the vertical adjustment of the adjustment seat 32, so that the recycled water at different depths can be drained and ultrafiltered. In particular, for recycled water with relatively poor water quality, the ultrafiltration membrane mechanism at a high position can effectively absorb and filter most of the suspended matter in the temporary storage tank 21, so that the suspended matter remains in the connecting pipe, while the ultrafiltration membrane mechanism at a low position can absorb a small amount of suspended matter in the subsequent drainage and pumping, thereby reducing the chance of clogging.

[0033] As a preferred embodiment, the plurality of diversion tubes 27 are fixed on the outer frame rod 31, and one end thereof slides and extends into the membrane tube 35 in the connecting tube 34. The lengths of each diversion tube 27 extending into the membrane tube 35 are different. A baffle plate 51 is fixed on the diversion tube 27 through a support rod 5, and a drainage gap is left between the baffle plate 51 and the inner wall of the membrane tube 35. In particular, when the recycled water is pumped to each diversion tube through a circulating pump, it can form a side wall impact in the membrane tube to achieve backwashing of the filter residue on the membrane tube, and the backwashing range of the diversion tube can be further increased under the lifting and lowering displacement of the adjustment seat, so as to achieve the effect of ultrafiltration and filter residue cleaning at the same time.

[0034] In this embodiment, there are two ultrafiltration membrane inner tubes 37 arranged on the left and right, and an inward concave notch is provided on the tube wall of the membrane tube 35 to form a filter residue retention recess. The side curvature of the filter residue retention recess is set to θ1, and the notch curvature is θ2. θ1 is smaller than θ2, thereby forming a nearly U-shaped inward concave notch, so that the filter residue around the membrane tube can accumulate in the filter residue retention recess, reducing the probability of clogging.

[0035] In this embodiment, a drainage bin 6 is provided below the temporary storage pool 21, and a stirring blade 61 is rotatably provided in the drainage bin 6, and the drainage bin 6 is provided with an extension path 62 along the tangential direction of the rotation of the stirring blade 61, and a grid device 63 is provided on the extension path 62. In particular, when the ultrafiltration membrane mechanism works for a long time, when the water pump operates at low power, the circulating pump can drain water normally so that the recycled water backwashes in the membrane tube, and discharges the filter residue in the filter residue retention recess to the connecting pipe. At this time, the rotation of the stirring blade in the drainage bin generates centrifugal force, and the filter residue can enter the extension path and be discharged, thereby achieving self-cleaning and avoiding accumulation and blockage.

[0036] Based on the research on the characteristics of biological aerated filter, the main indicators of its effluent water quality are compared with the inlet water requirements of submerged ultrafiltration (see the table below):

[0037] project Effluent indicators of biological aerated filter Immersed ultrafiltration water requirements Turbidity <2.0NTU <10.0NTU SS <10 mg / L <100mg / L

[0038] Therefore, the use of aerated biological filter technology to deeply treat urban recycled water can meet the water source requirements of boiler feed water and heat network supplementary water treatment system;

[0039] Based on the research on the characteristics of submerged ultrafiltration, the main indicators of its effluent water quality are compared with the inlet water requirements of the reverse osmosis (pre-desalination) system (see the table below):

[0040] project Immersed ultrafiltration effluent indicators Reverse osmosis water requirements Turbidity <0.10NTU <1.0 NT SDI ＜3 ＜5 SS <1mg / L <10 mg / L

[0041] Therefore, the deep treatment of urban recycled water by the aerated biological filter process can meet the water standards of power plants, and the water produced by the submerged ultrafiltration can meet the water inlet requirements of the subsequent pre-desalination system and ion desalination system.

[0042] Specifically, urban recycled water, used as boiler feed water, is processed through a biological aeration filter process combined with submerged ultrafiltration and reverse osmosis membrane treatment, achieving Class A standards. Class A reclaimed water enters the power plant, where it undergoes raw water pretreatment in the biological aeration filter process, saving water and turning waste into valuable resources. A water circulation system, connected to the ultrafiltration membrane and drainage components via a circulation pipe and external pipes, allows for continuous ultrafiltration treatment, ensuring effective ultrafiltration while preventing residue from clogging the membrane.

[0043] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An urban recycled water treatment system based on immersion ultrafiltration, characterized by: It includes: An inlet pipe is used to connect to the water pipe of the sewage treatment plant, one end of the inlet pipe is connected to the aeration biological filter (1), and an immersion ultrafiltration device (2) is provided outside the aeration biological filter (1), and the immersion ultrafiltration device (2) can filter and intercept SS and small molecular organic matter that has not been decomposed; A mixed ion exchanger (14) is provided outside the biological aeration filter (1), a drainage end of the submerged ultrafiltration device (2) is connected to the mixed ion exchanger (14), a reverse osmosis device (11) is provided outside the submerged ultrafiltration device (2), and SS and undecomposed small molecular organic matter trapped in the submerged ultrafiltration device (2) can enter the reverse osmosis device (11) through a pipeline; The reverse osmosis device (11) is externally connected to a primary desalination device (13), and both the primary desalination device (13) and the mixed ion exchanger (14) are provided with drainage pipes, and the residual water after treatment in the primary desalination device (13) can enter the mixed ion exchanger (14) through a transfer pipe; the mixed ion exchanger (14) is also externally connected to a desalination water tank (12); The submerged ultrafiltration device (2) comprises: a temporary storage tank (21) connected to the aerated biological filter (1); two ultrafiltration membrane mechanisms (3) are fixed overhead in the temporary storage tank (21); a flow tank (22) is provided on one side of the temporary storage tank (21); a drainage assembly (4) is fixed in the flow tank (22); The drainage assembly (4) is also connected to a circulation pipe (25), a circulation pump (26) is installed on the flow pool (22), one end of the circulation pipe (25) is connected to the circulation pump (26), and the circulation pump (26) is connected to a plurality of shunt pipes (27), and one end of each shunt pipe (27) is connected to the ultrafiltration membrane mechanism (3); The ultrafiltration membrane mechanism (3) comprises: an outer frame rod (31) suspended and fixed in the temporary storage tank (21); an adjustment seat (32) is slidably provided on the outer frame rod (31); and a plurality of connecting pipes (34) are vertically arranged below the adjustment seat (32); A membrane tube (35) is vertically arranged in the connecting tube (34), and an ultrafiltration membrane inner tube (37) is also arranged in the membrane tube (35); A plurality of diversion tubes (27) are fixed on the outer frame rod (31), and one end thereof slides and extends into the membrane tube (35) in the connecting tube (34); a baffle plate (51) is fixed on the diversion tube (27) via a support rod (5); There are two inner ultrafiltration membrane tubes (37) arranged on the left and right, and a concave notch is provided on the tube wall of the membrane tube (35), forming a filter residue retention recess; A water pump (23) is installed on the ultrafiltration membrane mechanism (3), and the water pump (23) is connected to each of the ultrafiltration membrane mechanisms (3) through a branch pipe. An external pipe (24) is provided at the discharge port of the water pump (23) and is connected to the drainage assembly (4); The drainage assembly (4) comprises: a flowing water tank (41), an end cover is fixed at the upper end thereof, a flow channel (42) is provided on the end cover, the external pipe (24) is connected to the flow channel (42), a membrane grid (43) is fixed in the flowing water tank (41), and a negative pressure pipe (44) is provided at the middle of the lower end face of the flowing water tank (41), the negative pressure pipe (44) is connected to the membrane grid (43), the circulation pipe (25) is connected to one side of the lower end face of the flowing water tank (41), and the negative pressure pipe transports the regenerated water in the flowing water tank to the flow pool after re-ultrafiltration by the membrane grid under negative pressure pumping; The two ultrafiltration membrane mechanisms (3) have the same composition structure. A confluence bin (33) is installed on the adjustment seat (32). One end of the connecting pipe (34) is connected to the confluence bin (33). A sealing ring (36) is provided between the connecting pipe (34), the membrane tube (35) and the ultrafiltration membrane inner tube (37).

2. The urban recycled water treatment system based on immersion ultrafiltration according to claim 1, characterized in that: The connecting pipes (34) in the two ultrafiltration membrane mechanisms (3) can be installed at different heights under vertical adjustment of the adjustment seat (32).

3. The urban recycled water treatment system based on immersion ultrafiltration according to claim 1, characterized in that: The lengths of the diversion pipes (27) extending into the membrane tube (35) are different, and a drainage gap is left between the baffle plate (51) and the inner wall of the membrane tube (35).

4. The urban recycled water treatment system based on immersion ultrafiltration according to claim 1, characterized in that: A drainage bin (6) is provided below the temporary storage tank (21), a stirring blade (61) is rotatably provided in the drainage bin (6), and an extension path (62) is provided in the drainage bin (6) along the tangential direction of the rotation of the stirring blade (61), and a grid device (63) is provided on the extension path (62).

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