Near-zero-discharge wastewater treatment system

Abstract

The invention discloses a near-zero-discharge wastewater treatment system which comprises an ultrapure water treatment system, a wastewater treatment system, a reclaimed water treatment system and a distillation system, the ultrapure water treatment system is used for treating the municipal water supply, distilled water treated by the distillation system and recycled water treated by the recycled water treatment system, carrying out ultrapure water treatment on the municipal water supply, the distilled water and the recycled water, conveying the treated ultrapure water to the FAB treatment production workshop, and supplying the treated ultrapure water to the FAB treatment production workshop for use. According to the invention, the distillation system is adopted to replace the existing water recovery system, and the distillation system is formed by the distillation equipment, so that the occupied area of the system can be effectively reduced, and the use cost of the space is reduced; according to the method, the distillation equipment is adopted to directly perform high-pressure low-temperature distillation on the second-class production wastewater in the FAB production workshop to generate distilled water, and then the distilled water is conveyed into the ultrapure water production system, so that the treatment process of the second-class production wastewater is effectively simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a near-zero emission wastewater treatment system. Background Art

[0002] When building RF filter wafer production lines and RF module packaging and testing production lines, it is necessary to treat production wastewater. The existing practice is to treat the municipal water supply with ultrapure water and then supply it to the FAB production workshop for use. The wastewater produced by the FAB production workshop is treated by the wastewater treatment system to remove internal grinding wastewater, fluorine-containing wastewater, ammonia nitrogen wastewater, organic wastewater, copper-containing wastewater, nickel-containing wastewater, silver-containing wastewater, arsenic-containing wastewater, gold-containing wastewater and acid-base wastewater, etc. The treated wastewater is then transported to the recycled water system for treatment to meet the municipal water supply standards, and then the ultrapure water system is used to form an internal circulation of water resources. In order to prevent the small molecular clusters of total organic carbon (TOC) from increasing the defect density of the gate oxide film and thus affecting the device performance, the wastewater discharged from the FAB production workshop is When the TOC is removed, the wastewater is directly transported to the wastewater treatment system for treatment. The second type of wastewater contains TOC small molecules. The second type of wastewater will be transported to the recycled water system for treatment. The wastewater in the recycled water system is transported to the cooling tower and the washing tower for treatment. The wastewater treated by the cooling tower and the washing tower is divided into three parts: the first part of the wastewater from which the TOC small molecules have been removed is directly transported to the wastewater treatment system for treatment. The second part meets the municipal water supply standards and is directly transported to the ultrapure water system for treatment. The third part is the situation where there are still too many TOC small molecules in the water. It is treated in the return water recovery system. Through this system, near-zero discharge of wastewater can be achieved to achieve internal circulation of water (such as Figure 8 shown).

[0003] However, there are some disadvantages in recycling wastewater that does not meet the requirements of the wastewater treatment system through a water recycling system. For example, in the water recycling system, the use of equipment such as cooling towers and washing towers will take up a lot of space, and the treatment process is complicated and the treatment efficiency is low. Therefore, a water treatment system is needed. This system can not only solve the impact of TOC small molecule aggregation in wastewater on the wastewater treatment system and ultrapure water system, but also reduce the occupied space, simplify the water treatment process and improve the treatment efficiency. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the prior art that the use of a recycled water system causes the equipment to occupy too much space, the treatment process to be complicated, and the treatment efficiency to be low, and to propose a near-zero emission wastewater treatment system.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A near-zero emission wastewater treatment system comprises an ultrapure water treatment system, a wastewater treatment system, a regenerated water treatment system and a distillation system; the ultrapure water treatment system is used to treat municipal water supply, distilled water treated by a distillation system and regenerated water treated by a regenerated water treatment system, and the municipal water supply, distilled water and regenerated water are subjected to ultrapure water treatment, and the treated ultrapure water is transported to a FAB treatment production workshop and supplied to the FAB treatment production workshop for use; the wastewater treatment system is used to receive first-class production wastewater discharged from the FAB production workshop that meets the requirements of the wastewater treatment system, and remove impurities in the first-class production wastewater to form primary treated water, and the primary treated water is transported to the regenerated water system for treatment; the regenerated water treatment system is used to treat the primary treated water so that the treated primary treated water meets the municipal water standard for regenerated water, and the regenerated water is transported to the ultrapure water system; the distilled water system uses a distillation device to receive the second-class production wastewater generated in the FAB production workshop, and converts the second-class production wastewater into distilled water through a distillation process, and the distilled water is transported to the ultrapure water system.

[0007] Preferably, the ultrapure water treatment system adopts 2B3T-RO-SC / SA-CP process.

[0008] Preferably, the first category of production wastewater includes production machine drainage, waste liquid, backwash wastewater, regeneration wastewater, washing tower wastewater, cooling tower wastewater and miscellaneous wastewater in the FAB production workshop; it also includes grinding wastewater, fluorine-containing wastewater, ammonia nitrogen wastewater, organic wastewater, copper-containing wastewater, nickel-containing wastewater, silver-containing wastewater, arsenic-containing wastewater, gold-containing wastewater and acid-base wastewater.

[0009] Preferably, the second category of production wastewater is wastewater other than the first category of production wastewater.

[0010] Preferably, the distillation equipment includes an evaporating cylinder, a sewage cover is detachably installed on one side of the evaporating cylinder, the evaporating cylinder is arranged on a heating hood, the top of the evaporating cylinder is connected to a heat exchanger, the heat exchanger is connected to a vacuum pump and a water storage tank, an agitator is arranged inside the evaporating cylinder, the agitator is driven by a driving pulley through a transmission belt, the driving pulley is fixed on the power output shaft of the driving motor, the heating hood is connected to the drainage end of the circulating pump, the water inlet end of the circulating pump is connected to the heating box, and an opening is arranged on the top of the heating box.

[0011] Preferably, the agitator includes a rotating shaft, one end of which is rotatably mounted on the inner wall of the evaporator cylinder, and the other end of the rotating shaft passes through the other side wall of the evaporator cylinder and extends to the outside of the evaporator cylinder. The rotating shaft is fixedly provided with a driven pulley matching the transmission belt at one end located outside the evaporator cylinder, and also includes a plurality of plates equidistantly mounted on the surface of the rotating shaft, the plates are of a triangular structure, and a cleaning mechanism is commonly fixed at the three corners of the plurality of plates.

[0012] Preferably, the cleaning mechanism comprises a plate body embedded at a corner of the plate body, a groove is provided on a side wall of the plate body, an elastic member is provided inside the groove, and a scraper is also provided inside the groove.

[0013] Preferably, the scraper is a U-shaped structure, one side of the scraper overlaps with the elastic member, the end of the scraper passes through the groove and is placed outside the groove, and contacts with the inner wall of the evaporating tube.

[0014] Preferably, the heat exchanger includes an outer shell, an external circulation pipe is arranged inside the outer shell, both ends of the external circulation pipe respectively penetrate the side walls of the outer shell, a plurality of metal sheets are arranged at the part of the external circulation pipe placed inside the outer shell, a wedge-shaped block is arranged at the bottom of the outer shell, an exhaust pipe connected to the vacuum pump is installed through one side of the bottom of the metal sheet, an air inlet pipe connected to the evaporating cylinder is installed through the top of the outer shell, a drain pipe connected to the water tank is installed through the other side of the bottom of the outer shell, and the exhaust pipe penetrates the wedge-shaped block.

[0015] Preferably, the interior of the heating cover is a hollow structure, and a heating tube is arranged inside the heating box.

[0016] The present invention has the following beneficial effects:

[0017] 1. In the present invention, a distillation system is used to replace the existing water recovery system. By using distillation equipment to form a distillation system, the floor space of the system can be effectively reduced, thereby reducing the cost of using space.

[0018] 2. In the present invention, the second type of production wastewater in the FAB production workshop is directly subjected to high-pressure and low-temperature distillation by using distillation equipment to produce distilled water, and then the distilled water is transported to the ultrapure water production system, which effectively simplifies the treatment process of the second type of production wastewater.

[0019] 3. In the present invention, the second type of production wastewater is directly treated by distillation equipment, which reduces operations such as washing and filtration, greatly improves the treatment efficiency of the second type of wastewater, and shortens the treatment time of the second type of wastewater.

[0020] 4. In the present invention, the agitator provided in the distillation equipment can effectively clean the solidified matter retained by the distilled water from the inner wall of the evaporation barrel, and then the inside of the evaporation barrel can be cleaned by flushing, without manual cleaning, thereby reducing the later maintenance of the distillation equipment.

[0021] 5. In the present invention, the distillation equipment is provided to perform distillation in a high-pressure and low-temperature manner, which can effectively save energy and reduce the total organic carbon content in water to a certain extent, thereby reducing the subsequent maintenance work of other equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1is a system flow chart of the present invention;

[0023] Figure 2 This is one of the overall structural schematic diagrams of the distillation equipment of the present invention;

[0024] Figure 3 The second schematic diagram of the overall structure of the distillation equipment of the present invention;

[0025] Figure 4 It is a schematic cross-sectional view of the distillation equipment of the present invention;

[0026] Figure 5 It is a schematic diagram of the structure of the agitator of the present invention;

[0027] Figure 6 It is a schematic diagram of the cleaning mechanism structure of the present invention;

[0028] Figure 7 It is a schematic diagram of the internal structure of the heat exchanger of the present invention;

[0029] Figure 8 This is a diagram of a wastewater treatment system in the prior art.

[0030] In the figure: 1, evaporating cylinder; 101, water inlet pipe; 2, drain cover; 3, heating hood; 4, heat exchanger; 401, outer shell; 402, external circulation pipe; 403, metal sheet; 404, wedge block; 405, air inlet pipe; 406, drain pipe; 407, exhaust pipe; 5, vacuum pump; 6, water storage tank; 7, heating box; 701, heating pipe; 8, circulation pump; 9, agitator; 901, rotating shaft; 902, plate body; 903, driven pulley; 904, cleaning mechanism; 904a, plate body; 904b, T-slot; 904c, elastic member; 904d, T-scraper; 10, transmission belt; 11, driving pulley; 12, driving motor. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] Reference Figure 1-7, a near-zero emission wastewater treatment system, including an ultrapure water treatment system, a wastewater treatment system, a reclaimed water treatment system and a distillation system; the ultrapure water treatment system is used to treat municipal water supply, distilled water treated by the distillation system and reclaimed water treated by the reclaimed water treatment system, and the municipal water supply, distilled water and reclaimed water are subjected to ultrapure water treatment, and the treated ultrapure water is transported to the FAB treatment production workshop and supplied to the FAB treatment production workshop for use; the wastewater treatment system is used to receive the first type of production wastewater discharged by the FAB production workshop that meets the requirements of the wastewater treatment system, and remove impurities in the first type of production wastewater to form primary treated water, and the primary treated water is transported to the reclaimed water system for treatment; the reclaimed water treatment system is used to treat the primary treated water, so that the treated primary treated water meets the municipal water standard for reclaimed water, and the reclaimed water is transported to the ultrapure water system; the distilled water system uses a distillation device to receive the second type of production wastewater generated in the FAB production workshop, and converts the second type of production wastewater into distilled water through a distillation process, and transports the distilled water to the ultrapure water system.

[0033] In this embodiment, when using the ultrapure water treatment system to treat municipal water supply, at least the following steps are included:

[0034] Step 1, pretreatment: First, the water is coarsely filtered to remove larger particles and suspended matter, usually using a sand filter, activated carbon filter, etc.

[0035] Step 2: Reverse Osmosis (RO): Use a reverse osmosis membrane to remove most of the dissolved matter, salts and other impurities in the water.

[0036] Step 3: Ion exchange: Use cation exchange resin and anion exchange resin to further remove dissolved ions in the water and reduce the ion concentration in the water.

[0037] Step 4: Remove organic matter: Use ultrafiltration or activated carbon adsorption to remove organic matter from water.

[0038] Step 5: Ultraviolet sterilization: Use ultraviolet lamps to disinfect bacteria and microorganisms in the water to ensure clean water quality.

[0039] Step 6: Ultrafiltration: Use ultrafiltration membrane to further remove fine particles and microorganisms in the water to ensure the purity of the water.

[0040] In this embodiment, when the wastewater treatment system is used to treat the first production wastewater, at least the following steps are included:

[0041] Step 1: Wastewater collection: The first type of wastewater is collected in different wastewater pools according to its composition.

[0042] The second step is wastewater regulation: the wastewater in the wastewater pool is subjected to preliminary physical, chemical and biological adjustments to keep the quality, flow rate, temperature and other parameters of the wastewater stable so that the subsequent treatment process can run efficiently and stably.

[0043] The third step is chemical filtration: According to the different components in different wastewater, chemical adjustments are carried out to remove impurities in the water.

[0044] Step 4: Acid-base adjustment: Adjust the acid-base of the water in the pool to avoid acid-base imbalance.

[0045] In this embodiment, when using the reclaimed water treatment system to treat primary treated water, at least the following steps are included:

[0046] Step 1: Pretreatment: Use coarse screens / sieves, oil-water separators and grit chambers to remove large particles, grease, suspended solids, etc. in the water to protect subsequent treatment equipment.

[0047] Step 2, primary treatment: Remove most of the suspended solids and organic matter in the water through physical and chemical methods to reduce the pollution load in the water.

[0048] Step 3: Secondary treatment: Remove dissolved organic matter and biodegradable pollutants in wastewater through biodegradation. This process mainly relies on the metabolism of microorganisms to degrade organic matter,

[0049] Step 4: Tertiary treatment: Remove harmful substances that still exist after secondary treatment, such as nitrogen, phosphorus, heavy metals, residual organic matter, and pathogenic microorganisms, to ensure that the water quality meets the reuse standards.

[0050] Step 5: Disinfection: The last step to ensure that the recycled water does not contain pathogenic microorganisms and meets hygiene standards.

[0051] In this embodiment, the primary treated water after treatment by the wastewater treatment system must comply with the "Pollutant Emission Standards for the Semiconductor Industry" (DB32 / 3747-2020).

[0052] In the present invention, the ultrapure water treatment system adopts the 2B3T-RO-SC / SA-CP process.

[0053] In the present invention, the first category of production wastewater includes production machine drainage, waste liquid, backwash wastewater, regeneration wastewater, washing tower wastewater, cooling tower wastewater and miscellaneous wastewater in the FAB production workshop; it also includes grinding wastewater, fluorine-containing wastewater, ammonia nitrogen wastewater, organic wastewater, copper-containing wastewater, nickel-containing wastewater, silver-containing wastewater, arsenic-containing wastewater, gold-containing wastewater and acid-base wastewater.

[0054] In the present invention, the second category of production wastewater refers to wastewater other than the first category of production wastewater.

[0055] In the present invention, the distillation equipment includes an evaporating cylinder 1, a sewage cover 2 is detachably installed on one side of the evaporating cylinder 1, the evaporating cylinder 1 is arranged on a heating cover 3, the top of the evaporating cylinder 1 is connected to a heat exchanger 4, the heat exchanger 4 is connected to a vacuum pump 5 and a water storage tank 6, an agitator 9 is arranged inside the evaporating cylinder 1, the agitator 9 is driven by a driving pulley 11 through a driving belt 10, the driving pulley 11 is fixed on the power output shaft of the driving motor 12, the heating cover 3 is connected to the drainage end of the circulating pump 8, the water inlet end of the circulating pump 8 is connected to the heating box 7, and the top of the heating box 7 is provided with an opening.

[0056] In this embodiment, after the evaporating cylinder 1 is externally connected to the second type of production wastewater in the FAB production workshop, the air pressure in the evaporating cylinder 1 is reduced by the vacuum pump 5, thereby reducing the boiling point of the second type of production wastewater in the evaporating cylinder 1, and then a water source is injected into the heating box 7 and heated. The hot water in the heating box 7 is pumped into the heating cover 3 by the circulating pump 8, and finally the water in the evaporating cylinder 1 is heated by the heating cover 3 to make the water in the evaporating cylinder 1 boil. The water vapor flows into the heat exchanger 4 under the action of negative pressure. Under the action of the heat exchanger 4, the water vapor condenses into liquid and flows into the water storage tank 6. The water storage tank 6 is connected to the ultrapure water system to send the distilled water into the ultrapure water system for treatment, thereby realizing water circulation.

[0057] In the present invention, the agitator 9 includes a rotating shaft 901, one end of which is rotatably mounted on the inner wall of the evaporating cylinder 1, and the other end of the rotating shaft 901 passes through the other side wall of the evaporating cylinder 1 and extends to the outside of the evaporating cylinder 1. The rotating shaft 901 is fixedly provided with a driven pulley 903 matching the transmission belt 10 at one end located outside the evaporating cylinder 1; it also includes a plurality of plates 902 equidistantly mounted on the surface of the rotating shaft 901, the plates 902 are of a triangular structure, and a cleaning mechanism 904 is fixed at the three corners of the plurality of plates 902.

[0058] In this embodiment, the agitator 9 is driven to rotate by the driving motor 12 to accelerate the evaporation of water in the evaporating cylinder 1. At the same time, the cleaning mechanism 904 can clean the inner wall of the evaporating cylinder 1 to prevent crystallized substances from adhering to the inner wall of the evaporating cylinder 1.

[0059] In the present invention, the cleaning mechanism 904 includes a plate 904a embedded in the corner of the plate 902, a T-shaped slot 904b is provided on the side wall of the plate 904a, an elastic member 904c is provided inside the T-shaped slot 904b, and a T-shaped scraper 904d is also provided inside the T-shaped slot 904b.

[0060] In this embodiment, the inner wall of the evaporating cylinder 1 is cleaned by the T-shaped scraper 904d. When encountering crystalline substances, the elastic member 904c can play a certain buffering role, thereby playing a certain self-protection role for the T-shaped scraper 904d.

[0061] In the present invention, the T-shaped scraper 904d is a T-shaped structure, one side of the T-shaped scraper 904d overlaps with the elastic member 904c, the end of the T-shaped scraper 904d passes through the T-shaped slot 904b and passes through the T-shaped slot 904b and is placed outside the T-shaped slot 904b, and contacts with the inner wall of the evaporating tube 1.

[0062] In the present invention, the heat exchanger 4 includes an outer shell 401, an outer circulation pipe 402 is arranged inside the outer shell 401, both ends of the outer circulation pipe 402 respectively penetrate the side walls of the outer shell 401, a portion of the outer circulation pipe 402 placed inside the outer shell 401 is provided with a plurality of metal sheets 403, a wedge block 404 is arranged at the bottom of the outer shell 401, an exhaust pipe 407 connected to the vacuum pump 5 is installed through one side of the bottom of the metal sheet 403, an air intake pipe 405 connected to the evaporating tube 1 is installed through the top of the outer shell 401, a drain pipe 406 connected to the water storage tank 6 is installed through the other side of the bottom of the outer shell 401, and the exhaust pipe 407 penetrates the wedge block 404.

[0063] In this embodiment, the temperature of the outer circulation pipe 402 is lowered by connecting the outer circulation pipe 402 to a fluid with a lower temperature. After the metal sheet 403 absorbs the temperature of the outer circulation pipe 402, the temperature of the metal sheet 403 begins to decrease. When the steam with a higher temperature touches the metal sheet 403, it begins to condense. The condensed water is discharged through the drain pipe 406. The connecting pipe between the drain pipe 406 and the water storage tank 6 is provided with a solenoid valve. When the vacuum pump 5 evacuates the evaporating tube 1, the solenoid valve can prevent the gas in the water storage tank 6 from being drawn out.

[0064] In the present invention, the interior of the heating cover 3 is a hollow structure, and a heating tube 701 is provided inside the heating box 7 .

[0065] In this embodiment, a solenoid valve is provided at the connection pipe between the heating box 7 and the heating cover 3 to prevent the water in the heating cover 3 from flowing back into the heating box 7 due to gravity when the circulation pump 8 is not working.

[0066] Synergy between systems:

[0067] The wastewater treatment system divides the wastewater generated from the FAB workshop into Class I and Class II wastewater. Class I wastewater is treated through the recycled water system, and Class II wastewater is treated through the distilled water system.

[0068] The recycled water system converts primary treated water into recycled water that meets municipal water standards and supplies it to the ultrapure water system.

[0069] The distilled water system treats the second type of wastewater, produces distilled water, and further provides ultrapure water treatment.

[0070] The ultrapure water system converts all water (municipal water, distilled water, recycled water, etc.) into ultrapure water through a strict treatment process for use in FAB production workshops.

[0071] The system treats wastewater and other water sources in multiple ways, and transforms them into water that meets high standards for use in semiconductor production through processes such as distillation, water recycling, and reverse osmosis. This efficient water resource management and recycling system not only meets production needs, but also minimizes water consumption and reduces wastewater discharge.

[0072] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A near-zero emission wastewater treatment system, characterized in that: Including ultrapure water treatment system, wastewater treatment system, recycled water treatment system and distillation system; The ultrapure water treatment system is used to treat municipal water supply, distilled water treated by the distillation system and regenerated water treated by the regenerated water treatment system, and to treat the municipal water supply, distilled water and regenerated water with ultrapure water, and to transport the treated ultrapure water to the FAB processing production workshop for use in the FAB processing production workshop; The wastewater treatment system is used to receive the first type of production wastewater discharged from the FAB production workshop that meets the requirements of the wastewater treatment system, remove impurities in the first type of production wastewater to form primary treated water, and transport the primary treated water to the reclaimed water system for treatment; The reclaimed water treatment system is used to treat primary treated water so that the treated primary treated water meets the municipal water standard for reclaimed water, and transport the reclaimed water to the ultrapure water system; The distilled water system uses a distillation device to receive the second type of production wastewater generated in the FAB production workshop, converts the second type of production wastewater into distilled water through a distillation process, and transports the distilled water to the ultrapure water system.

2. A near-zero discharge wastewater treatment system according to claim 1, characterized in that: The ultrapure water treatment system adopts the 2B3T-RO-SC / SA-CP process.

3. A near-zero discharge wastewater treatment system according to claim 1, characterized in that: The first category of production wastewater includes production machine drainage, waste liquid, backwash wastewater, regeneration wastewater, washing tower wastewater, cooling tower wastewater and miscellaneous wastewater in the FAB production workshop; it also includes grinding wastewater, fluorine-containing wastewater, ammonia nitrogen wastewater, organic wastewater, copper-containing wastewater, nickel-containing wastewater, silver-containing wastewater, arsenic-containing wastewater, gold-containing wastewater and acid-base wastewater.

4. A near-zero discharge wastewater treatment system according to claim 1, characterized in that: The second category of production wastewater is other wastewater except the first category of production wastewater.

5. A near-zero discharge wastewater treatment system according to claim 1, characterized in that: The distillation device comprises an evaporating cylinder (1), a sewage cover (2) is detachably mounted on one side of the evaporating cylinder (1), the evaporating cylinder (1) is arranged on a heating cover (3), the top of the evaporating cylinder (1) is connected to a heat exchanger (4), the heat exchanger (4) is connected to a vacuum pump (5) and a water storage tank (6), an agitator (9) is arranged inside the evaporating cylinder (1), the agitator (9) is driven by a driving pulley (11) through a driving belt (10), the driving pulley (11) is fixed on a power output shaft of a driving motor (12), the heating cover (3) is connected to a drainage end of a circulating pump (8), the water inlet end of the circulating pump (8) is connected to a heating box (7), and an opening is arranged on the top of the heating box (7).

6. A near-zero discharge wastewater treatment system according to claim 5, characterized in that: The agitator (9) comprises a rotating shaft (901), one end of the rotating shaft (901) is rotatably mounted on the inner wall of the evaporating cylinder (1), the other end of the rotating shaft (901) penetrates the other side wall of the evaporating cylinder (1) and extends to the outside of the evaporating cylinder (1), and a driven pulley (903) matching the transmission belt (10) is fixedly arranged at one end of the rotating shaft (901) located outside the evaporating cylinder (1); and further comprises a plurality of plates (902) equidistantly mounted on the surface of the rotating shaft (901), the plates (902) being of a triangular structure, and a cleaning mechanism (904) is commonly fixed at three corners of the plurality of plates (902).

7. A near-zero discharge wastewater treatment system according to claim 6, characterized in that: The cleaning mechanism (904) comprises a plate body (904a) embedded in a corner of a plate body (902), a T-shaped slot (904b) is provided on a side wall of the plate body (904a), an elastic member (904c) is provided inside the T-shaped slot (904b), and a T-shaped scraper (904d) is also provided inside the T-shaped slot (904b).

8. A near-zero discharge wastewater treatment system according to claim 7, characterized in that: The T-shaped scraper (904d) is a T-shaped structure, one side of the T-shaped scraper (904d) overlaps with the elastic member (904c), and the end of the T-shaped scraper (904d) passes through the T-shaped slot (904b) and is placed outside the T-shaped slot (904b) and contacts the inner wall of the evaporating cylinder (1).

9. A near-zero discharge wastewater treatment system according to claim 5, characterized in that: The heat exchanger (4) comprises an outer shell (401), an outer circulation pipe (402) is arranged inside the outer shell (401), both ends of the outer circulation pipe (402) respectively penetrate the side wall of the outer shell (401), a portion of the outer circulation pipe (402) disposed inside the outer shell (401) is provided with a plurality of metal sheets (403), a wedge block (404) is arranged at the bottom of the outer shell (401), an exhaust pipe (407) connected to a vacuum pump (5) is installed through one side of the bottom of the metal sheet (403), an air intake pipe (405) connected to an evaporating cylinder (1) is installed through the top of the outer shell (401), a drain pipe (406) connected to a water storage tank (6) is installed through the other side of the bottom of the outer shell (401), and the exhaust pipe (407) penetrates the wedge block (404).

10. A near-zero discharge wastewater treatment system according to claim 5, characterized in that: The interior of the heating cover (3) is a hollow structure, and the interior of the heating box (7) is provided with a heating tube (701).

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