Waste liquid treatment system and method and microsphere production line

Abstract

The invention relates to a waste liquid treatment technology, and discloses a waste liquid treatment system and method and a microsphere production line. The waste liquid treatment system comprises a feeding unit, a purification unit and a cleaning unit, and the purification unit comprises a membrane separator and a clarified liquid tank which are used for carrying out membrane permeation treatment on waste liquid; a feeding hole of the membrane separator is connected with the feeding unit, a clarified liquid outlet is connected with the clarified liquid tank, and a concentrated liquid outlet is connected with the feeding unit through a return pipeline; the cleaning unit comprises a cleaning liquid tank and a cleaning pump, a liquid inlet and a liquid outlet of the cleaning liquid tank are both connected with the membrane separator, the cleaning pump is located on a pipeline between the liquid outlet of the cleaning liquid tank and the membrane separator, and the clear liquid tank is connected with the liquid inlet of the cleaning liquid tank. The waste liquid treatment system can efficiently and quickly purify the waste liquid, and the purified liquid can be reused for production, so that the waste liquid treatment cost is reduced, and the microsphere production cost is reduced.

Description

Technical Field

[0001] The present invention relates to waste liquid treatment technology, and specifically, to a waste liquid treatment system and method, as well as a microsphere production line. Background Art

[0002] Microspheres are particulate matters with micron-sized dimensions, usually composed of polymers or inorganic materials, having a particle size between 1 - 1000 μm, and having good dispersibility and controllability. The importance of microspheres lies in their surface modification, which enables the surface of the microspheres to have special chemical and physical properties. Therefore, microspheres have broad application prospects in the fields of materials science, biomedicine, environmental hygiene, etc.

[0003] Existing microspheres are mainly divided into four categories. The first category is inorganic microspheres represented by silica gel microspheres. The second category is non-degradable polymer microspheres represented by polystyrene, polyacrylate, polymethyl methacrylate, polyacrylamide, etc., and a small amount of degradable polymer microspheres. The third category is organic-inorganic composite microspheres represented by polystyrene / silica magnetic microspheres. The fourth category is natural polymer microspheres such as agarose, chitosan, albumin, etc. prepared from polymer raw materials, or polyester-based biodegradable polymer microspheres such as polylactic acid, PLGA, polycaprolactone, etc.

[0004] The production process of microspheres generates a large amount of wastewater. In particular, the wastewater in the production of chromatography packing microspheres also contains impurities such as microspheres and colloids. Generally, if the COD value in the wastewater is high, it is necessary to entrust an external water treatment plant for subsequent treatment, resulting in high wastewater disposal costs and increasing the production cost of microspheres. If the COD value in the wastewater meets the treatment requirements of the sewage treatment station, it needs to be discharged to the sewage treatment station, which will also increase the treatment volume of the sewage treatment station.

[0005] Therefore, there is an urgent need to provide a device that can quickly purify and recycle the wastewater generated during the production process of microspheres. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems existing in the prior art, and provide a waste liquid treatment system and method, as well as a microsphere production line. The waste liquid treatment system can efficiently and quickly purify the waste liquid, and the purified liquid can be reused in production, reducing the waste liquid disposal cost and lowering the production cost of microspheres.

[0007] To achieve the above object, a first aspect of the present invention provides a waste liquid treatment system, which includes a feeding unit, a purification unit, and a cleaning unit. The purification unit includes a membrane separator for performing membrane permeation treatment on the waste liquid and a clarified liquid tank. The feed inlet of the membrane separator is connected to the feeding unit, the clarified liquid outlet is connected to the clarified liquid tank, and the concentrated liquid outlet is connected to the feeding unit through a reflux pipeline; the cleaning unit includes a cleaning liquid tank and a cleaning pump. The liquid inlet and the liquid outlet of the cleaning liquid tank are both connected to the membrane separator. The cleaning pump is located on the pipeline between the liquid outlet of the cleaning liquid tank and the membrane separator. The clarified liquid tank is connected to the liquid inlet of the cleaning liquid tank.

[0008] Preferably, the feeding unit includes a feed storage tank and a heat exchanger connected to the feed storage tank. A feed pump is provided on the pipeline between the feed storage tank and the heat exchanger. The heat exchanger is connected to the feed inlet of the membrane separator. The concentrated liquid outlet of the membrane separator is connected to the feed storage tank through the reflux pipeline.

[0009] More preferably, a membrane stack is provided in the membrane separator. The membrane stack is composed of at least two layers of ultrafiltration membranes stacked in sequence. The feed inlet and the concentrated liquid outlet of the membrane separator are located on one side of the membrane stack, and the clarified liquid outlet of the membrane separator is located on the other side of the membrane stack.

[0010] Further preferably, the preparation method of the ultrafiltration membrane includes: grinding biochar and mixing it with a polymer and a solvent in a mass ratio of 1:5 - 8:50 - 70 to form a membrane solution, and forming the ultrafiltration membrane from the membrane solution by the phase inversion method; wherein, the polymer is selected from one or more of polysulfone, polyethersulfone, and polyvinylidene fluoride, and the solvent is dimethylacetamide and / or dimethylformamide.

[0011] Specifically, the connection port of the membrane separator to the liquid inlet of the cleaning liquid tank and the concentrated liquid outlet of the membrane separator are located on the same side of the membrane stack, and the connection port of the membrane separator to the liquid outlet of the cleaning liquid tank and the clarified liquid outlet of the membrane separator are located on the same side of the membrane stack.

[0012] More specifically, the cleaning unit further includes a filter, and the filter is located on the pipeline between the cleaning pump and the membrane separator.

[0013] Typically, the waste liquid treatment system further includes a transfer device connected to the feeding unit, a sewage treatment device connected to the cleaning liquid tank, and a control unit. The feeding unit, the purification unit, and the cleaning unit are all electrically connected to the control unit.

[0014] A second aspect of the present invention provides a waste liquid treatment method, which uses the above waste liquid treatment system. The method includes the following steps:

[0015] S1. Feed the waste liquid into the membrane separator through the feed unit at the feed port of the membrane separator for membrane permeation treatment to obtain clarified liquid and concentrated liquid. Input the clarified liquid into the clarified liquid tank from the clarified liquid outlet of the membrane separator, and input the concentrated liquid into the feed unit through the reflux pipeline from the concentrated liquid outlet of the membrane separator.

[0016] S2. After each batch of liquid is treated by the membrane separator, input a part of the clarified liquid in the clarified liquid tank into the cleaning liquid tank, and then input it into the membrane separator through the cleaning pump to eject the residual concentrated liquid in the membrane separator, and input it into the feed unit through the reflux pipeline from the concentrated liquid outlet of the membrane separator.

[0017] Preferably, the method further includes: when the liquid flux of the membrane separator decreases during the treatment process, load the cleaning liquid into the cleaning liquid tank, use the cleaning pump to input the cleaning liquid into the membrane separator for cleaning, and then return from the membrane separator to the liquid inlet of the cleaning liquid tank to perform circulating cleaning on the membrane separator; the cleaning liquid is an inorganic acid-base cleaning agent, and the temperature of the cleaning liquid is 35-40°C.

[0018] The third aspect of the present invention provides a microsphere production line, including a microsphere production system and the above-mentioned waste liquid treatment system. The feed unit is connected to the waste liquid outlet of the microsphere production system, and the cleaning liquid tank is connected to the liquid inlet of the microsphere production system.

[0019] Through the above technical solutions, the waste liquid treatment system provided by the present invention can perform efficient membrane permeation purification treatment on waste liquid, especially suitable for microsphere production, with a high interception rate of impurities such as microspheres and colloids in microsphere waste liquid. The clarified liquid obtained by membrane permeation can be recycled to microsphere industrial production, which can not only reduce the cost of hazardous waste treatment and the treatment volume of the sewage treatment station in industrial production, but also effectively save the consumption of fresh water and other liquids in industrial production, with good economic and environmental benefits; the concentrated liquid obtained by membrane permeation is returned to the feed unit for continuous concentration, and then transported and processed after reaching the preset concentration multiple, more reasonably performing subsequent treatment on the waste liquid; after the batch waste liquid treatment is completed, the clarified liquid in the clarified liquid tank can be used to eject the residual concentrated liquid in the membrane separator through the cleaning unit to better maintain the flux of the membrane separator and improve the service life of the membrane separator.

[0020] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic flow chart of an embodiment of the waste liquid treatment system in the present invention.

[0022] Description of Reference Numerals

[0023] 1 Feed Unit 11 Feed Storage Tank

[0024] 12 Heat Exchanger 13 Feed Pump

[0025] 2 Purification Unit 21 Membrane Separator

[0026] 22 Clarified Liquid Tank 3 Cleaning Unit

[0027] 31 Cleaning Liquid Tank 32 Cleaning Pump

[0028] 33 Filter 4 Return Pipeline

[0029] A Cooling Liquid B Transfer Device

[0030] C Microsphere Production System D Waste Liquid Detailed Embodiments

[0031] The following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention and are not used to limit the present invention.

[0032] It should be understood that for the convenience of describing the present invention and simplifying the description, the terms "inner" and "outer" refer to the inside or outside of the corresponding device, and "upper" and "lower" refer to the upper side or lower side of the corresponding device; the terms are based on the orientation or positional relationship shown in the drawings, rather than indicating or implying that the device or equipment referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0033] The waste liquid treatment system provided in the first aspect of the present invention, see Figure 1 , includes a feed unit 1, a purification unit 2, and a cleaning unit 3. The purification unit 2 includes a membrane separator 21 for performing membrane permeation treatment on the waste liquid and a clarified liquid tank 22. The feed inlet of the membrane separator 21 is connected to the feed unit 1, the clarified liquid outlet is connected to the clarified liquid tank 22, and the concentrated liquid outlet is connected to the feed unit 1 through a return pipeline 4; the cleaning unit 3 includes a cleaning liquid tank 31 and a cleaning pump 32. The inlet and outlet of the cleaning liquid tank 31 are both connected to the membrane separator 21. The cleaning pump 32 is located on the pipeline between the outlet of the cleaning liquid tank 31 and the membrane separator 21. The clarified liquid tank 22 is connected to the inlet of the cleaning liquid tank 31.

[0034] In the present invention, valves can be provided on the connecting pipelines of the feeding unit 1, the purification unit 2, and the cleaning unit 3 according to the requirements of the waste liquid treatment process. For example, valves are respectively provided on the reflux pipeline 4, on the pipelines connecting the liquid inlet and outlet of the cleaning liquid tank 31 to the membrane separator 21, on the pipeline connecting the membrane separator 21 to the clarified liquid tank 22, on the pipeline connecting the feeding unit 1 to the membrane separator 21, and on the pipeline connecting the clarified liquid tank 22 to the liquid inlet of the cleaning liquid tank 31. Preferably, the waste liquid treatment system further includes a control unit. The feeding unit 1, the purification unit 2, and the cleaning unit 3 can be respectively connected to the control unit to control the operation and stop of the feeding unit 1, the purification unit 2, and the cleaning unit 3 through the control unit. Each valve preferably adopts an electronic valve to be able to cooperate with the control unit.

[0035] The waste liquid treatment system provided by the above basic technical solution can be applied to various industrial production processes, especially suitable for the production process of microspheres such as chromatography packing. Taking the application of this waste liquid treatment system in the production of chromatography packing microspheres as an example, connect the feeding unit 1 to the waste liquid outlet of the microsphere production system, and connect the clarified liquid tank 22 to any inlet that needs to input liquid in the microsphere production system. Refer to Figure 1 The specific use process is as follows: The waste liquid D generated by the microsphere production system enters the membrane separator 21 from the feed inlet of the membrane separator 21 through the feeding unit 1 for membrane permeation treatment to obtain the clarified liquid passing through the permeation membrane and the concentrated liquid not passing through the permeation membrane. The clarified liquid is input into the clarified liquid tank 22 from the clarified liquid outlet of the membrane separator 21 and recycled into the microsphere production system C. The concentrated liquid is input into the feeding unit 1 through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21 for further concentration. As the concentration of impurity particles such as microspheres and colloids contained in the waste liquid D in the feeding unit 1 becomes higher and higher, after reaching the preset concentration multiple, discharging and transporting are carried out from the feeding unit 1; after each batch of liquid is processed by the membrane separator 21, a part of the clarified liquid in the clarified liquid tank 22 is input into the cleaning liquid tank 31, and then input into the membrane separator 21 through the cleaning pump 32 to eject the residual concentrated liquid in the membrane separator 21, and input into the feeding unit 1 through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21;

[0036] If the flux of the membrane separator 21 decays and cannot return to the normal level after long-term use, the membrane separator 21 is chemically cleaned by using the cleaning unit 3. The cleaning liquid is filled into the cleaning liquid tank 31, and the cleaning liquid is input into the membrane separator 21 by using the cleaning pump 32 for cleaning, and then flows back to the liquid inlet of the cleaning liquid tank 31 from the membrane separator 21, so that the cleaning liquid circulates and cleans the membrane separator 21 multiple times. The pollutant concentration in the cleaned cleaning liquid is relatively low, and after pH neutralization, it can be discharged to the factory sewage treatment system for further treatment.

[0037] As a preferred embodiment of the present invention, the feed unit 1 includes a feed storage tank 11 and a heat exchanger 12 connected to the feed storage tank 11. A feed pump 13 is provided on the pipeline between the feed storage tank 11 and the heat exchanger 12. The heat exchanger 12 is connected to the feed inlet of the membrane separator 21, and the concentrated liquid outlet of the membrane separator 21 is connected to the feed storage tank 11 through a reflux pipeline 4. The provision of the feed storage tank 11 and the heat exchanger 12 enables a certain buffer to be formed before the waste liquid enters the membrane separator 21, and the waste liquid can be cooled through the heat exchanger 12 to avoid damage to the permeable membrane in the membrane separator 21 caused by too high a temperature of the waste liquid; through the reflux cooperation between the membrane separator 21 and the feed storage tank 11, the multiple concentration and enrichment of impurities such as microparticles and colloids in the waste liquid are effectively realized, facilitating subsequent transfer treatment and reducing the operating cost.

[0038] In the present invention, the feed storage tank 11 can be electrically connected to the control unit, and a liquid level monitor is provided in the feed storage tank 11. When the liquid level monitor detects that the waste liquid in the feed storage tank 11 reaches 2 / 3 of the height of the feed storage tank 11, the membrane separator 21 can be started to purify the waste liquid.

[0039] In the present invention, the heat exchanger 12 can be a plate heat exchanger, a tubular heat exchanger, a regenerative heat exchanger, etc. Preferably, a circulating cooling pipe is provided on the outer wall of the heat exchanger 12, and both ends of the circulating cooling pipe are connected to the supply device of the coolant to improve the heat exchange efficiency between the heat exchanger 12 and the waste liquid.

[0040] In the present invention, a permeable membrane is provided in the membrane separator 21 to perform membrane permeation treatment on the waste liquid. Preferably, a membrane stack is provided in the membrane separator 21. The membrane stack is composed of at least two layers of ultrafiltration membranes stacked in sequence. The feed inlet and the concentrated liquid outlet of the membrane separator 21 are located on one side of the membrane stack, and the clarified liquid outlet of the membrane separator 21 is located on the other side of the membrane stack. The main body of the ultrafiltration membrane has a first side surface for supplying the waste liquid and a second side surface for discharging the clarified liquid through the main body. After the waste liquid is treated by the ultrafiltration membrane, the clarified liquid is located on the side where the second side surface is located, and the feed inlet and the concentrated liquid of the membrane separator 21 are located on the side where the first side surface is located; through the provision of the membrane stack, the waste liquid can be subjected to multi-stage membrane separation, thereby improving the removal efficiency of impurities such as microspheres and colloids in the waste liquid and reducing the subsequent treatment cost of the waste liquid.

[0041] As a preferred embodiment of the ultrafiltration membrane, the pore size of the ultrafiltration membrane is 10-20 nm, and the ultrafiltration membrane is a hollow fiber ultrafiltration membrane made of polyvinylidene fluoride. The ultrafiltration membrane has a good interception and removal effect on microparticles and colloids in the waste liquid.

[0042] As another preferred embodiment of the ultrafiltration membrane, the preparation method of the ultrafiltration membrane includes: grinding biochar and mixing it with a polymer and a solvent in a mass ratio of 1:5-8:50-70 to form a membrane solution, and subjecting the membrane solution to evaporation, leaching, and cooling to form the ultrafiltration membrane; wherein, the polymer is selected from one or more of polysulfone, polyethersulfone, and polyvinylidene fluoride, and the solvent is dimethylacetamide and / or dimethylformamide. This ultrafiltration membrane can better intercept microparticles and colloids in the waste liquid, separate and remove them, and then the obtained clarified liquid can be recycled to the microsphere production, reducing interference with the production process.

[0043] Exemplarily, the preparation process of the ultrafiltration membrane is as follows: commercially available straw biochar is ground to 600 mesh, and then mixed with dry polysulfone and dimethylacetamide in a mass ratio of 1:6:60, and ultrasonic treatment is carried out until it becomes transparent grayish-black as the membrane solution, and the above-mentioned membrane solution is phase-changed into a membrane through evaporation, leaching, and cooling.

[0044] In the present invention, the connection port of the membrane separator 21 to the inlet or outlet of the cleaning liquid tank 31 can be located on any side of the membrane separator 21, as long as the cleaning liquid can be input into the membrane separator 21 to perform contact cleaning on the membrane separator 21. As a preferred embodiment of the present invention, the connection port of the membrane separator 21 to the inlet of the cleaning liquid tank 31 and the concentrated liquid outlet of the membrane separator 21 are located on the same side of the membrane stack, and the connection port of the membrane separator 21 to the outlet of the cleaning liquid tank 31 and the clarified liquid outlet of the membrane separator 21 are located on the same side of the membrane stack.

[0045] At this time, after each batch of feed liquid is processed by the membrane separator 21, a part of the clarified liquid in the clarified liquid tank 22 is input into the cleaning liquid tank 31, and then input into the side of the membrane stack opposite to the concentrated liquid through the cleaning pump 32 to perform backwashing on the membrane stack, eject the residual concentrated liquid in the membrane stack, and pass through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21 into the feeding unit 1, improving the collection efficiency of the concentrated liquid. After long-term use, if the flux of the membrane stack decays and cannot return to the normal level, the cleaning liquid is filled into the cleaning liquid tank 31, and the cleaning liquid is input into the side of the membrane separator 21 opposite to the membrane stack and the intercepted impurities through the cleaning pump 32 to perform backwashing on the membrane stack to ensure the stable operation of the system and achieve a good ability to remove impurities; the cleaning liquid after backwashing then flows back from the membrane separator 21 to the inlet of the cleaning liquid tank 31, so that the cleaning liquid performs multiple cycles of cleaning on the membrane separator 21.

[0046] As a preferred embodiment of the cleaning unit 3 in the present invention, the cleaning unit 3 further includes a filter 33, and the filter 33 is located on the pipeline between the cleaning pump 32 and the membrane separator 21 to filter the cleaning liquid entering the membrane separator 21 by using the filter 33, avoiding a large amount of impurities from entering the membrane separator 21 and causing membrane pollution.

[0047] As a preferred embodiment of the present invention, the waste liquid treatment system further includes a transfer device connected to the feeding unit 1 and a sewage treatment device connected to the cleaning liquid tank 31, so that after the concentration of particulate impurities in the feeding unit 1 reaches a preset concentration, the transfer device is used for collection and treatment, and the cleaning liquid in the cleaning liquid tank 31 enters the sewage treatment device for further treatment after cleaning the membrane separator 21.

[0048] Based on the technical solution of the above waste liquid treatment system, the second aspect of the present invention provides a waste liquid treatment method, which uses the aforementioned waste liquid treatment system, and the method includes the following steps:

[0049] S1. Feed the waste liquid into the membrane separator 21 from the feed port of the membrane separator 21 through the feeding unit 1 for membrane permeation treatment to obtain a clarified liquid and a concentrated liquid. Input the clarified liquid into the clarified liquid tank 22 from the clarified liquid outlet of the membrane separator 21, and input the concentrated liquid into the feeding unit 1 through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21.

[0050] S2. After each batch of liquid is treated by the membrane separator 21, input a part of the clarified liquid in the clarified liquid tank 22 into the cleaning liquid tank 31, and then input it into the membrane separator 21 through the cleaning pump 32 to eject the residual concentrated liquid in the membrane separator 21, and input it into the feeding unit 1 through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21.

[0051] The waste liquid treatment method provided by the present invention can not only efficiently purify the waste liquid, recycle the clarified liquid, but also effectively simplify the subsequent treatment process of the concentrated liquid, and the operation stability of the whole treatment method is high, effectively reducing the treatment cost of the waste liquid.

[0052] According to the present invention, preferably, the method further includes: when the liquid flux of the membrane separator 21 decreases during the treatment process, load the cleaning liquid into the cleaning liquid tank 31, input the cleaning liquid into the membrane separator 21 through the cleaning pump 32 for cleaning, and then return from the membrane separator 21 to the liquid inlet of the cleaning liquid tank 31 to perform circulating cleaning on the membrane separator 21. Among them, the membrane flux refers to the fluid volume passing through a unit membrane area per unit time.

[0053] In the present invention, the cleaning liquid is preferably an inorganic acid-base cleaning agent, for example, sodium hydroxide solution, hydrochloric acid solution, etc. Preferably, the temperature of the cleaning liquid is 35-40 °C to improve the cleaning efficiency of the ultrafiltration membrane and quickly restore the flux of the ultrafiltration membrane.

[0054] The third aspect of the present invention provides a microsphere production line, which includes a microsphere production system and the aforementioned waste liquid treatment system. The feeding unit 1 is connected to the waste liquid outlet of the microsphere production system, and the cleaning liquid tank 31 is connected to the liquid inlet of the microsphere production system.

[0055] As a relatively preferred specific embodiment of the microsphere production line in the present invention, refer to Figure 1 , which includes a microsphere production system and a waste liquid treatment system. The waste liquid treatment system includes a feeding unit 1, a purification unit 2, a cleaning unit 3, a control unit, a transfer device, and a sewage treatment device. The purification unit 2 includes a membrane separator 21 for performing membrane permeation treatment on the waste liquid and a clarified liquid tank 22. The feeding unit 1 includes a feeding storage tank 11 and a heat exchanger 12 connected to the feeding storage tank 11. A feeding pump 13 is provided on the pipeline between the feeding storage tank 11 and the heat exchanger 12. The heat exchanger 12 is connected to the feeding port of the membrane separator 21. A liquid level monitor is provided in the feeding storage tank 11. A circulating cooling pipe is provided on the outer wall of the heat exchanger 12, and both ends of the circulating cooling pipe are connected to a coolant supply device; the concentrated liquid outlet of the membrane separator 21 is connected to the feeding storage tank 11 through a reflux pipeline 4. The feeding port of the membrane separator 21 is connected to the heat exchanger 12, the clarified liquid outlet is connected to the clarified liquid tank 22, and the concentrated liquid outlet is connected to the feeding storage tank 11 through the reflux pipeline 4. A membrane stack is provided in the membrane separator 21, and the membrane stack is composed of at least two layers of ultrafiltration membranes stacked in sequence. The feeding port, the concentrated liquid outlet of the membrane separator 21, and the connection port between the membrane separator 21 and the liquid inlet of the cleaning liquid tank 31 are located on one side of the membrane stack. The clarified liquid outlet of the membrane separator 21 and the connection port between the membrane separator 21 and the liquid outlet of the cleaning liquid tank 31 are located on the other side of the membrane stack. The pore size of the ultrafiltration membrane is 10-20 nm, and the ultrafiltration membrane is a hollow fiber ultrafiltration membrane made of polyvinylidene fluoride; the cleaning unit 3 includes a cleaning liquid tank 31, a cleaning pump 32, and a filter 33. The liquid inlet and outlet of the cleaning liquid tank 31 are both connected to the membrane separator 21. The cleaning pump 32 is located on the pipeline between the liquid outlet of the cleaning liquid tank 31 and the membrane separator 21. The filter 33 is located on the pipeline between the cleaning pump 32 and the membrane separator 21. The clarified liquid tank 22 is connected to the liquid inlet of the cleaning liquid tank 31; the transfer device is connected to the feeding storage tank 11, and the sewage treatment device is connected to the cleaning liquid tank 31; the feeding storage tank 11, the heat exchanger 12, the feeding pump 13, the membrane separator 21, the coolant supply device, the cleaning pump 32 are electrically connected to the control unit. Solenoid valves connected to the control unit are respectively provided on the reflux pipeline 4, on the pipelines where the liquid inlet and outlet of the cleaning liquid tank 31 are connected to the membrane separator 21, on the pipeline where the membrane separator 21 is connected to the clarified liquid tank 22, on the pipeline where the clarified liquid tank 22 is connected to the cleaning liquid tank 31, and on the pipeline where the heat exchanger 12 is connected to the membrane separator 21. The feeding storage tank 11 is connected to the waste liquid outlet of the microsphere production system, and the cleaning liquid tank 31 is connected to the liquid inlet of the microsphere production system.

[0056] The waste liquid treatment process of this microsphere production line is as follows: Refer to Figure 1, the specific usage process is as follows: Inject the waste liquid D generated by the microsphere production system C into the feed storage tank 11. When the liquid level monitor detects that the waste liquid in the feed storage tank 11 reaches 2 / 3 of the height of the feed storage tank 11, open the solenoid valves on the pipeline connecting the heat exchanger 12 and the membrane separator 21, on the pipeline connecting the membrane separator 21 and the clarified liquid tank 22, and on the reflux pipeline 4. Start the feed pump 13, the membrane separator 21, and the coolant supply device. After cooling the waste liquid D with the coolant A in the heat exchanger 12, it enters the membrane separator 21 from the feed port of the membrane separator 21 and undergoes membrane permeation treatment through the membrane stack to obtain the clarified liquid passing through the membrane stack and the concentrated liquid not passing through the membrane stack. The clarified liquid is input into the clarified liquid tank 22 from the clarified liquid outlet of the membrane separator 21 and recycled to the microsphere production system C from the clarified liquid tank 22. The concentrated liquid is input into the feed unit 1 through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21 for further concentration. As the concentrations of impurity particles such as microspheres and colloids contained in the waste liquid D in the feed storage tank 11 become higher and higher, after reaching the preset concentration multiple, discharge the material from the feed storage tank 11 to the transfer device B; After each batch of liquid is processed by the membrane separator 21, close the solenoid valves on the pipeline connecting the heat exchanger 12 and the membrane separator 21 and on the pipeline connecting the membrane separator 21 and the clarified liquid tank 22. Close the feed pump 13, the membrane separator 21, and the coolant supply device. Open the solenoid valves on the pipeline connecting the inlet and outlet of the cleaning liquid tank 31 and the membrane separator 21 and on the pipeline connecting the clarified liquid tank 22 and the cleaning liquid tank 31. Start the cleaning pump 32 to input a part of the clarified liquid in the clarified liquid tank 22 into the cleaning liquid tank 31, and then input it into the membrane separator 21 to eject the residual concentrated liquid in the membrane separator 21, and input it into the feed storage tank 11 through the reflux pipeline 4 from the concentrated liquid outlet of the membrane separator 21. The ejected concentrated liquid will be diluted to a certain extent and can be combined with the next batch of liquid for treatment;

[0057] If the flux of the membrane separator 21 decays and cannot return to the normal level after long-term use, load the cleaning liquid into the cleaning liquid tank 31, open the solenoid valve on the pipeline connecting the inlet and outlet of the cleaning liquid tank 31 and the membrane separator 21, start the cleaning pump 32, and use the cleaning pump 32 to input the cleaning liquid into the membrane separator 21 for cleaning, and then return it from the membrane separator 21 to the inlet of the cleaning liquid tank 31, so that the cleaning liquid can clean the membrane separator 21 multiple times in a cycle. The pollutant concentration in the cleaned cleaning liquid is relatively low, and after pH neutralization, it can be discharged to the factory sewage treatment system for further treatment.

[0058] As can be seen from the above description, the waste liquid treatment system provided by the present invention can efficiently purify waste liquid by membrane permeation. In particular, it is suitable for microsphere production, has a high interception rate for impurities such as microspheres and colloids in microsphere waste liquid, and the clarified liquid obtained by membrane permeation can be recycled to microsphere industrial production. This not only reduces the cost of hazardous waste treatment and the treatment volume of the sewage treatment station in industrial production, but also effectively saves the consumption of liquids such as fresh water in industrial production, and has good economic and environmental benefits. The concentrated liquid obtained by membrane permeation is returned to the feeding unit 1 for further concentration, and after reaching the preset concentration multiple, it is then transported for treatment, more reasonably performing subsequent treatment on the waste liquid. After the batch waste liquid treatment is completed, the clarified liquid in the clarified liquid tank 22 can be used to eject the residual concentrated liquid in the membrane separator 21 through the cleaning unit 3, so as to better maintain the flux of the membrane separator 21 and improve the service life of the membrane separator 21.

[0059] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0060] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0061] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A waste liquid treatment system, characterized in that, it includes a feeding unit (1), a purification unit (2) and a cleaning unit (3). The purification unit (2) includes a membrane separator (21) for performing membrane permeation treatment on waste liquid and a clarified liquid tank (22). The feed inlet of the membrane separator (21) is connected to the feeding unit (1), the clarified liquid outlet is connected to the clarified liquid tank (22), and the concentrated liquid outlet is connected to the feeding unit (1) through a reflux pipeline (4). The cleaning unit (3) includes a cleaning liquid tank (31) and a cleaning pump (32). The liquid inlet and the liquid outlet of the cleaning liquid tank (31) are both connected to the membrane separator (21). The cleaning pump (32) is located on the pipeline between the liquid outlet of the cleaning liquid tank (31) and the membrane separator (21). The clarified liquid tank (22) is connected to the liquid inlet of the cleaning liquid tank (31).

2. The waste liquid treatment system according to claim 1, characterized in that, the feeding unit (1) includes a feed storage tank (11) and a heat exchanger (12) connected to the feed storage tank (11). A feed pump (13) is arranged on the pipeline between the feed storage tank (11) and the heat exchanger (12). The heat exchanger (12) is connected to the feed inlet of the membrane separator (21). The concentrated liquid outlet of the membrane separator (21) is connected to the feed storage tank (11) through the reflux pipeline (4).

3. The waste liquid treatment system according to claim 1 or 2, characterized in that, a membrane stack is arranged in the membrane separator (21). The membrane stack is composed of at least two layers of ultrafiltration membranes stacked in sequence. The feed inlet and the concentrated liquid outlet of the membrane separator (21) are located on one side of the membrane stack, and the clarified liquid outlet of the membrane separator (21) is located on the other side of the membrane stack.

4. The waste liquid treatment system according to claim 3, characterized in that, the preparation method of the ultrafiltration membrane includes: grinding biochar and mixing it with a polymer and a solvent in a mass ratio of 1:5 - 8:50 - 70 to form a membrane solution, and forming the ultrafiltration membrane from the membrane solution by the phase inversion method; wherein, the polymer is selected from one or more of polysulfone, polyethersulfone and polyvinylidene fluoride, and the solvent is dimethylacetamide and / or dimethylformamide.

5. The waste liquid treatment system according to claim 3, characterized in that, the connection port of the membrane separator (21) with the liquid inlet of the cleaning liquid tank (31) and the concentrated liquid outlet of the membrane separator (21) are located on the same side of the membrane stack, and the connection port of the membrane separator (21) with the liquid outlet of the cleaning liquid tank (31) and the clarified liquid outlet of the membrane separator (21) are located on the same side of the membrane stack.

6. The waste liquid treatment system according to claim 1 or 2, characterized in that, the cleaning unit (3) further includes a filter (33), and the filter (33) is located on the pipeline between the cleaning pump (32) and the membrane separator (21).

7. The waste liquid treatment system according to claim 1 or 2, characterized in that, The waste liquid treatment system further includes a transfer device connected to the feeding unit (1), a sewage treatment device connected to the cleaning liquid tank (31), and a control unit. The feeding unit (1), the purification unit (2), and the cleaning unit (3) are all electrically connected to the control unit.

8. A waste liquid treatment method, characterized in that it uses the waste liquid treatment system according to any one of claims 1 to 7, and this method includes the following steps: S1. Feed the waste liquid into the membrane separator (21) from the feed port of the membrane separator (21) through the feeding unit (1) for membrane permeation treatment to obtain a clarified liquid and a concentrated liquid. Input the clarified liquid into the clarified liquid tank (22) from the clarified liquid outlet of the membrane separator (21), and input the concentrated liquid into the feeding unit (1) through the reflux pipeline (4) from the concentrated liquid outlet of the membrane separator (21); S2. After each batch of liquid is treated by the membrane separator (21), input a part of the clarified liquid in the clarified liquid tank (22) into the cleaning liquid tank (31), and then input it into the membrane separator (21) through the cleaning pump (32) to eject the residual concentrated liquid in the membrane separator (21), and input it into the feeding unit (1) through the reflux pipeline (4) from the concentrated liquid outlet of the membrane separator (21).

9. The waste liquid treatment method according to claim 8, characterized in that this method further includes: when the liquid flux of the membrane separator (21) decreases during the treatment process, load the cleaning liquid into the cleaning liquid tank (31), use the cleaning pump (32) to input the cleaning liquid into the membrane separator (21) for cleaning, and then return it from the membrane separator (21) to the liquid inlet of the cleaning liquid tank (31) to perform cyclic cleaning on the membrane separator (21); the cleaning liquid is an inorganic acid-base cleaning agent, and the temperature of the cleaning liquid is 35 - 40 °C.

10. A microsphere production line, characterized in that it includes a microsphere production system and the waste liquid treatment system according to any one of claims 1 to 7. The feeding unit (1) is connected to the waste liquid outlet of the microsphere production system, and the cleaning liquid tank (31) is connected to the liquid inlet of the microsphere production system.

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