An ordered crystallization-based near-saturation wastewater treatment system and method

Abstract

The application discloses a kind of near-saturation state wastewater treatment system and method based on ordered crystallization, it is related to industrial wastewater treatment field, the system includes cooling tower and crystallization pool, and first circulation pipeline for transporting wastewater in crystallization pool to cooling tower and second circulation pipeline for transporting wastewater in cooling tower to crystallization pool are connected between crystallization pool and cooling tower;Crystallization tank capable of lifting and moving out is placed in crystallization pool, the tank wall of crystallization tank is multilayer, at least including inner frame layer, dense phase lining layer and outer frame layer sequentially arranged from inside to outside, biomass particles are placed in crystallization tank, and the particle size of biomass particles is greater than the aperture of dense phase lining layer.The application is used to solve the technical problems that multiple-effect evaporation crystallization process is easy to disordered crystallization and energy consumption is high when treating wastewater.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment, and in particular to a near-saturated wastewater treatment system and method based on ordered crystallization. Background Technology

[0002] In the field of wastewater treatment, multi-effect evaporation crystallization is one of the mainstream treatment processes, which has many advantages such as relatively mature technology, wide range of treatable wastewater, fast treatment speed, high degree of automation, and low operation difficulty.

[0003] However, multi-effect evaporation crystallization processes generally require heating to continuously evaporate and concentrate wastewater. The wastewater first reaches a near-saturated state, then continues to be heated to concentrate it into a supersaturated state, and then continues heating to achieve crystallization. On the one hand, this evaporation crystallization method consumes a high amount of steam and electricity, resulting in high wastewater treatment costs. On the other hand, the salt crystallization in multi-effect evaporation crystallizers is disordered and poorly controllable, especially prone to crystallizing on the container walls and pipes, causing wall climbing and pipe blockage, affecting heat transfer efficiency and equipment stability, requiring regular cleaning and maintenance. In addition, due to the complex composition of wastewater, which often contains various corrosive substances, crystallization on the container walls and pipes can also cause corrosion of the pipes and containers, resulting in severe corrosion during the overall equipment operation and a short lifespan. This necessitates higher standards in equipment material selection, increasing equipment investment costs. Summary of the Invention

[0004] The present invention aims to provide a near-saturated wastewater treatment system and method based on ordered crystallization, in order to solve the technical problems of disordered crystallization and high energy consumption in the treatment of wastewater by multi-effect evaporation crystallization process.

[0005] To solve the above technical problems, the specific solution adopted by the present invention is: a near-saturated wastewater treatment system based on ordered crystallization, comprising a cooling tower and a crystallization tank.

[0006] A first circulation pipeline for transporting wastewater from the crystallization tank to the cooling tower and a second circulation pipeline for transporting wastewater from the cooling tower to the crystallization tank are connected between the crystallization tank and the cooling tower.

[0007] The crystallization pool contains a crystallization tank that can be lifted and removed. The tank wall is multi-layered, including at least an inner frame layer, a dense phase liner layer, and an outer frame layer arranged sequentially from the inside to the outside. Biomass pellets are placed in the crystallization tank, and the particle size of the biomass pellets is larger than the pore size of the dense phase liner layer.

[0008] As a further optimization of the above technical solution, the water inlet of the cooling tower is located at its upper part, and a water pump is installed on the first circulation pipeline.

[0009] As a further optimization of the above technical solution, the cooling tower is a spray cooling tower.

[0010] As a further optimization of the above technical solution, the biomass pellets are bamboo powder.

[0011] As a further optimization of the above technical solution, the dense phase liner is made of nylon fabric, and both the inner frame layer and the outer frame layer are made of steel woven mesh.

[0012] As a further optimization of the above technical solution, a drain pool is provided outside the crystallization pool, and a transfer mechanism for transferring the crystallization tank is provided between the crystallization pool and the drain pool.

[0013] As a further optimization of the above technical solution, the transfer mechanism includes a slide rail suspended above the crystallization tank and the dewatering tank, with a hook connected to the slider of the slide rail, and a hanging ring adapted to the hook is provided on the crystallization tank.

[0014] As a further optimization of the above technical solution, two mounting brackets are provided at intervals on the outer sides of the crystallization tank and the dewatering tank, and the slide rail is laterally supported on the two mounting brackets.

[0015] As a further optimization of the above technical solution, a buffer tank is connected to one side of the crystallization pool, and the buffer tank is connected to the crystallization pool pipeline.

[0016] A method for treating near-saturated wastewater based on ordered crystallization is provided. The method is based on the above-mentioned wastewater treatment system. Near-saturated wastewater in the multi-effect evaporation crystallization process is transported to a cooling tower. After being cooled and concentrated in the cooling tower, the supersaturated wastewater is transported to a crystallization tank. The salts in the supersaturated wastewater are induced to crystallize by biomass particles in the crystallization tank, thereby reducing the concentration of the supersaturated wastewater. The wastewater with reduced concentration is then transported back to the cooling tower for concentration and cooling. This cycle is repeated N times. Once the wastewater in the crystallization tank is reduced to the target concentration, it is discharged from the crystallization tank.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention involves setting up a crystallization tank and placing a crystallization trough within it. Biomass pellets are then placed in the crystallization trough to induce crystallization in supersaturated wastewater. The salts and minerals in the supersaturated wastewater crystallize onto the biomass pellets, achieving orderly crystallization within a designated area. This avoids pipe blockage and wall climbing caused by chaotic salt crystallization, ensuring equipment stability, strong controllability, and simple operation.

[0019] This invention enables various salts to crystallize in a designated area, facilitating cleaning and collection. It also minimizes corrosion to equipment during operation, significantly extending service life and reducing costs.

[0020] This invention uses a cooling tower to cool the wastewater to be treated. When the wastewater passes through the cooling tower, on the one hand, the water evaporates, realizing the concentration of the near-saturated wastewater. On the other hand, the temperature of the wastewater drops after passing through the cooling tower, and the solubility of salts in the wastewater decreases. Evaporation and concentration and the change in solubility together realize the conversion of near-saturated brine to supersaturated brine, which facilitates the induction of crystallization in the crystallization device.

[0021] The cooling tower concentrates unsaturated salts in near-saturated wastewater through natural evaporation, eliminating the need for additional heating devices. This avoids the energy consumption and carbon dioxide generation associated with heating devices, making it environmentally friendly and resource-saving. The entire concentration process is carried out at a relatively low temperature, allowing the system to achieve crystallization with lower energy input, thus reducing energy consumption. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the wastewater treatment system in this invention;

[0023] Figure 2 This is a side view of the wastewater treatment system in this invention;

[0024] Figure 3 This is a schematic side cross-sectional view of the crystallization pool;

[0025] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0026] Figure 5 This is a schematic diagram of the transfer mechanism;

[0027] Figure 6 for Figure 5 Enlarged view of point B in the middle;

[0028] Figure 7 for Figure 5 Enlarged view of point C in the middle;

[0029] Figure 8 This is a top view schematic diagram of the wastewater treatment system of the present invention;

[0030] Figure 9 for Figure 8 A cross-sectional view along the BB direction;

[0031] Figure 10 for Figure 9 Enlarged view at point D;

[0032] Figure 11 for Figure 9 Enlarged view at point E in the middle;

[0033] Reference numerals: 1. Cooling tower; 101. Tower base; 102. Liquid collection tank; 103. Air inlet channel; 104. Tower body; 105. Spraying mechanism; 1051. Spray pipe; 1052. Nozzle; 106. Bionic lung mist-catching layer; 2. Water pump; 3. First circulation pipeline; 4. Second circulation pipeline; 5. Mounting bracket; 501. Support rod; 502. Crossbar; 503. Diagonal brace; 504. Roller 6. Crystallization tank; 601. Support platform; 602. Support bar; 7. Buffer tank; 8. Crystallization tank; 801. Inner frame layer; 802. Dense phase lining layer; 803. Outer frame layer; 804. Mounting platform; 9. Transfer mechanism; 901. Slide rail; 902. Slider; 903. Pull rope; 904. Hook; 10. Drainage tank; 11. Hanging ring; 12. Third circulation pipeline; 13. Fourth circulation pipeline. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Parts not described or disclosed in detail in the following embodiments of the present invention should be understood as prior art known or should be known by those skilled in the art.

[0035] like Figure 1 , 2 As shown, the present invention discloses a near-saturated wastewater treatment system based on ordered crystallization, including a cooling tower 1 and a crystallization pool 6. A first circulation pipeline 3 for transporting wastewater in the crystallization pool 6 to the cooling tower 1 and a second circulation pipeline 4 for transporting wastewater in the cooling tower 1 to the crystallization pool 6 are connected between the crystallization pool 6 and the cooling tower 1.

[0036] Cooling tower 1 is a naturally ventilated spray cooling tower, and its structure is existing technology. The liquid to be cooled is transported to the upper part of the tower body and then sprayed into the tower through the water inlet opened at the upper part of the tower body 104. At the same time, air inlet channels are opened in the tower wall to allow natural wind to enter, and natural wind is used to cool the liquid inside the tower. For ease of understanding, the structure of the spray cooling tower is briefly described as follows:

[0037] Combination Figure 8-11 As shown, the spray cooling tower includes a tower body 104, a liquid collection tank 102 disposed inside the tower body 104 and located at the bottom of the tower body 104, and a spray mechanism 105 disposed inside the tower body 104 and located above the liquid collection tank 102. The spray mechanism 105 includes a spray pipe 1051 and a plurality of nozzles 1052 installed on the spray pipe 1051. The spray pipe 1051 is horizontally disposed inside the tower body 104. The liquid inlet of the spray pipe 1051 passes through the water inlet of the cooling tower 1 and is connected to the liquid outlet of the first circulation pipeline 3, so that the wastewater in the crystallization tank 6 passes through the first circulation pipeline 3 and the spray pipe 1051 and is sprayed into the tower body 104 through the nozzles 1052.

[0038] Above the tower body 104, a biomimetic lung-like mist-catching layer 106 is designed to intercept fog droplets. This layer includes multiple layers of mist-catching nets spaced apart and polyhedral environmentally friendly spherical packing material placed on the nets. Airflow must pass through more than 120 deflection curves within this layer before entering the atmosphere. This structure prevents salt-containing fog droplets from escaping into the atmosphere, and the escape rate can be controlled to be less than or equal to 0.1 PPM. A cleaning water pipe is installed on the biomimetic lung-like mist-catching layer 106 for online cleaning. The inlet of the cleaning water pipe is connected to the first circulation pipe 3, and a control valve is installed on the cleaning water pipe.

[0039] In other embodiments of the present invention, the cleaning water pipe may also be connected to a separate cleaning water source.

[0040] Multiple air inlet channels 103 are provided on the side wall of the tower body 104. Natural air enters the tower body 104 through the air inlet channels 103 to cool the wastewater solution inside the tower body 104. The cooled wastewater is collected in the liquid collection tank 102. The second circulation pipeline 4 is connected to the liquid collection tank 102 to transport the wastewater in the liquid collection tank 102 to the crystallization pool 6.

[0041] The spray mechanism 105 is located on the upper part of the tower body 104 and is higher than the crystallization pool 6. Therefore, a water pump 2 is installed on the first circulation pipeline 3 to pump the water in the crystallization pool 6 into the spray mechanism 105 of the cooling tower 1.

[0042] The liquid collection tank 102 is installed on the tower base 101 at the bottom of the tower body 104. The liquid collection tank 102 is positioned higher than the crystallization tank 6, and the waste liquid in the liquid collection tank 102 can be overflowed and transported to the crystallization tank 6 along the second circulation pipeline 4. It is understood that in order to facilitate the flow of wastewater between the cooling tower 1 and the crystallization tank 8, a water pump can also be installed on the second circulation pipeline 4.

[0043] An external discharge pipeline (not shown in the figure) is installed on the crystallization tank 6. A commercially available water quality tester is installed on the external discharge pipeline. When the water quality tester detects that the water quality meets the discharge standards, the external discharge pipeline is opened, and the treated wastewater flows out of the crystallization tank 6.

[0044] like Figure 3 , 4 As shown, a crystallization tank 8 that can be lifted and removed is placed inside the crystallization pool 6. Both the crystallization pool 6 and the crystallization tank 8 are open at the top, and both have circular cross-sections. The cross-sectional diameter of the crystallization tank 8 is smaller than that of the crystallization pool 6, and the side wall height of the crystallization tank 8 is lower than that of the crystallization pool 6.

[0045] The outlet of the second circulation pipe 4 passes through the side wall of the crystallization tank 6 and extends into the crystallization tank 6. The crystallization tank 8 is placed behind the crystallization tank 6, and the outlet is higher than the upper edge of the crystallization tank 8. The axis of the outlet of the second circulation pipe 4 is tangent to the outer circular surface of the crystallization tank 8, so that the wastewater flowing out of the second circulation pipe 4 flows into the crystallization tank 6 tangentially, forming a vortex in the crystallization tank 6. A gap is left between the outlet of the second circulation pipe 4 and the outer wall of the crystallization tank 8 to prevent the outlet from interfering with the movement of the crystallization tank 8 in and out of the crystallization tank 6.

[0046] The crystallization tank 8 has multiple layers, including at least an inner frame layer 801, a dense phase liner layer 802, and an outer frame layer 803 arranged sequentially from the inside out. In this embodiment, the crystallization tank 8 has three layers, including a side wall and a bottom wall. Both the side wall and the bottom wall include an inner frame layer 801, a dense phase liner layer 802, and an outer frame layer 803. The inner frame layer 801 and the outer frame layer 803 are made of steel woven mesh, and the dense phase liner layer 802 is made of nylon cloth. The mesh size of the inner frame layer 801 and the outer frame layer 803 is larger than the aperture of the dense phase liner layer 802. Since the dense phase liner layer 802 is made of flexible material, the inner frame layer 801 and the outer frame layer 803 can provide support for the dense phase liner layer 802.

[0047] A support bar 602 is provided at the bottom of the crystallization tank 6. When the crystallization tank 8 is placed in the crystallization tank 6, the support bar 602 supports the bottom of the crystallization tank 8, so that there is a gap between the bottom of the crystallization tank 8 and the bottom of the crystallization tank 6. A protruding annular support platform 601 is provided on the inner circumferential side of the side wall of the crystallization tank 6, and a protruding annular mounting platform 804 is provided on the upper edge of the outer frame layer 803. When the crystallization tank 8 is placed in the crystallization tank 6, the support platform 601 is supported below the mounting platform 804. This not only leaves a gap between the side wall of the crystallization tank 8 and the side wall of the crystallization tank 6, but also uses the annular support platform 601 to position the crystallization tank 8, preventing the crystallization tank 8 from tilting or shaking due to water flow impact in the crystallization tank 6.

[0048] Biomass particles are placed inside the crystallization tank 8, and the particle size of the biomass particles is larger than the pore size of the dense phase liner 802. The biomass particles are material particles with a large specific surface area. In this embodiment, the biomass particles are bamboo powder with a particle size of 40-60 mesh, obtained by crushing bamboo. The bamboo powder fibers serve as crystal nuclei to induce crystallization of salts in the waste liquid that have reached supersaturation, thereby crystallizing the salts within the crystallization tank 8.

[0049] like Figure 1 , 10As shown, a draining tank 10 is provided outside the crystallization tank 6. The draining tank 10 has a circular cross-section, and its size is the same as or larger than that of the crystallization tank 6, so that the crystallization tank 8 can be transferred into the draining tank 10 to drain the crystallized salt in the crystallization tank 8. A third circulation pipe 12 is connected to the draining tank 10. The third circulation pipe 12 is connected in parallel to the first circulation pipe 3, and the connection point between the third circulation pipe 12 and the first circulation pipe 3 is located upstream of the water pump 2, so that the wastewater falling into the draining tank 10 is pumped into the cooling tower 1 through the first circulation pipe 3 for cooling and concentration treatment.

[0050] like Figure 1 , 5 As shown in Figure 6, a transfer mechanism 9 for transferring the crystallization tank 8 is provided between the crystallization tank 6 and the drain tank 10. The transfer mechanism 9 includes a slide rail 901 suspended above the crystallization tank 6 and the drain tank 10. A hook 904 is connected to the slider 902 of the slide rail 901, and a hanging ring 11 adapted to the hook 904 is provided on the crystallization tank 8. Specifically, two mounting brackets 5 are spaced apart on the outer sides of the crystallization tank 6 and the drain tank 10. The slide rail 901 is laterally supported on the two mounting brackets 5, and the two mounting brackets 5 are respectively fixed to both ends of the slide rail 901. The specific fixing method is existing technology, and welding or bolt connection is acceptable.

[0051] Combination Figure 7 As shown, each mounting bracket 5 includes a vertical support rod 501 and a horizontal bar 502 vertically fixed to the lower end of the support rod 501. The support rod 501 is vertically connected to the middle of the horizontal bar 502. A diagonal brace 503 connects the support rod 501 and the horizontal bar 502. One end of the diagonal brace 503 is fixed to the end of the horizontal bar 502, and the other end is fixed to the rod body of the support rod 501. Two rollers 504 are spaced apart at the bottom of the horizontal bar 502 to allow the transfer mechanism 9 to move when pushed by an external force, adjusting the position of the transfer mechanism 9 according to the actual application scenario.

[0052] The two mounting brackets 5 are at the same height, and the slide rail 901 is horizontally set. A slider 902 is mounted on the slide rail 901, allowing it to slide. Specifically, a pulley is rotatably mounted on the slider 902, and the slide rail 901 has a track for the pulley to slide on. The sliding of the pulley on the track drives the slider 902 to slide on the slide rail 901. The slider 902 can also be mounted on the slide rail 901 using other methods of existing technology, as long as it ensures that the slider 902 can move on the slide rail 901; these will not be elaborated further here.

[0053] An electric hoist is installed on the slider 902. The electric hoist is a commercially available product and will not be described in detail here. The electric hoist is equipped with a pull rope 903, and a hook 904 is installed at the end of the pull rope 903. The upper surface of the mounting platform 804 of the crystallization tank 8 is provided with hanging rings 11. There are multiple hanging rings 11, which are spaced apart around the circumference of the hanging rings 11. In this embodiment, there are three hanging rings 11. The hook 904 is hung on the hanging rings 11, and the electric hoist is controlled to move the pull rope 903 upward to remove the crystallization tank 8 from the crystallization pool 6. Then, the slider 902 is controlled to slide along the slide rail 901 to transfer the crystallization tank 8 from the crystallization pool 6 to the drain pool 10.

[0054] To facilitate the lifting of the crystallization tank 8 by the hook 904, the transfer mechanism 9 of the present invention is equipped with an auxiliary chain (not shown in the figure). The auxiliary chain includes a main chain and three branch chains connected to the end of the main rope. Each branch chain has a hook at its end, and the main chain has a hook at its end away from the branch chain. In use, the hook on each branch chain is connected to a hanging ring 11, and the hook on the main rope is connected to the hook 904, thereby lifting the crystallization tank 8. The three branch chains are of the same length, which helps to maintain the stability of the crystallization tank 8.

[0055] During wastewater treatment, after a certain amount of salt crystals are stored in the crystallization tank 8, the crystallization tank 8 is lifted by an electric hoist, and the slider 902 is controlled to move along the slide rail 901 to transfer the crystallization tank 8 to the draining tank 10 for draining. The drained salt crystals are then sent to a subsequent collection device for further processing. In this embodiment, the slider 902 can be moved on the slide rail 901 by manually pushing the crystallization tank 8, thereby realizing the transfer of the crystallization tank 8. In other embodiments of the present invention, an electric slider 902 can also be set on the slide rail 901, and the movement of the slider 902 can be remotely controlled to realize the transfer of the crystallization tank 8.

[0056] A buffer tank 7 is connected to one side of the crystallization pool 6. The buffer tank 7 is connected to the crystallization pool 6 through the fourth circulation pipeline 13. When there is too much wastewater to be treated in the crystallization pool 6, it is transported to the buffer tank 7 through the fourth circulation pipeline 13 for buffering. When the amount of wastewater to be treated in the crystallization pool 6 decreases, it is then sent back into the crystallization pool 6 from the buffer tank 7.

[0057] This invention also discloses a method for treating near-saturated wastewater based on ordered crystallization. The method uses the aforementioned wastewater treatment system and includes the following steps: Near-saturated wastewater from a multi-effect evaporation crystallization process is transported to a cooling tower 1. After being cooled and concentrated in the cooling tower 1, the supersaturated wastewater is transported to a crystallization tank 6. Salts in the supersaturated wastewater are induced to crystallize by biomass particles in the crystallization tank 6, thereby reducing the concentration of the supersaturated wastewater. The wastewater with reduced concentration is then transported back to the cooling tower 1 for concentration and cooling. This cycle is repeated N times, where N is a natural number not less than 1. Once the wastewater in the crystallization tank 6 has been reduced to the target concentration, it is discharged from the crystallization tank 6.

[0058] Specifically, in this method, the near-saturated wastewater from the multi-effect evaporation crystallization process is first transported to the crystallization tank 6 as mother liquor, and then biomass pellets are added to the mother liquor. Near-saturated wastewater continues to be fed into the crystallization tank 6, while simultaneously turning on the water pump 2 on the first circulation pipeline 3 to pump the wastewater from the crystallization tank 6 into the cooling tower 1. After being cooled by the cooling tower 1, the wastewater falls into the liquid collection tank 102 at the bottom of the cooling tower 1, and is then sent back to the crystallization tank 6 through the second circulation pipeline 4. The wastewater, after being cooled and concentrated by the cooling tower 1, undergoes a dual effect of evaporation and cooling; on the one hand, the water evaporates, making the solution... As the concentration increases, and the solubility of salts decreases after cooling, the near-saturated wastewater becomes supersaturated wastewater after concentration in cooling tower 1. This supersaturated wastewater is then transported to crystallization tank 6, where salt minerals crystallize on biomass particles, achieving orderly crystallization in a designated area. After crystallization, the wastewater concentration in crystallization tank 6 decreases. The wastewater is then pumped back into cooling tower 1 through the first circulation pipeline 3, and this cycle is repeated N times. When the wastewater concentration in crystallization tank 6 drops to the target level and the water quality analyzer detects that the water quality is acceptable, the wastewater is discharged through the external discharge pipeline. During this process, if there is excessive wastewater in crystallization tank 6, the valve on the fourth circulation pipeline 13 is opened, and the wastewater is transported to buffer tank 7 for buffering. Once the amount of wastewater to be treated in crystallization tank 6 decreases, it is then fed back into crystallization tank 6 from buffer tank 7.

[0059] This invention relates to a near-saturated wastewater treatment system and method based on ordered crystallization. In addition to inducing crystallization of salts in industrial wastewater, it can also be used to crystallize solutions containing calcium and magnesium ions to separate and recover these ions. Existing technologies generally use reverse osmosis membranes to treat calcium and magnesium ions, but calcium and magnesium ions easily adhere to the reverse osmosis membrane, making separation difficult. By using the treatment system and method of this invention, calcium and magnesium ions are induced to crystallize in a crystallization tank, which can effectively separate them.

[0060] It should be noted that the near-saturated wastewater flowing out of the multi-effect evaporation crystallization process in this invention refers to wastewater that has been evaporated and concentrated by the multi-effect evaporator but has not crystallized. This wastewater may contain a variety of salts, and the solubility of these salts is not completely consistent. Therefore, even after one concentration and cooling in the cooling tower, it may not reach a supersaturated state. By circulating the wastewater multiple times between the crystallization tank and the cooling tower, the salts in the wastewater gradually reach supersaturation. The supersaturated salts crystallize in the crystallization tank through bamboo powder fiber induction, while the salts that have not reached a supersaturated state continue to circulate with the wastewater.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A near-saturated wastewater treatment system based on ordered crystallization, characterized in that: Includes a cooling tower (1) and a crystallization pool (6); A first circulation pipe (3) for transporting wastewater from the crystallization tank (6) to the cooling tower (1) and a second circulation pipe (4) for transporting wastewater from the cooling tower (1) to the crystallization tank (6) are connected between the crystallization tank (6) and the cooling tower (1). The crystallization tank (6) contains a crystallization tank (8) that can be lifted and removed. The tank wall of the crystallization tank (8) is multi-layered, including at least an inner frame layer (801), a dense phase liner layer (802) and an outer frame layer (803) arranged sequentially from the inside to the outside. Biomass particles are placed in the crystallization tank (8), and the particle size of the biomass particles is larger than the pore size of the dense phase liner layer (802). The outlet of the second circulation pipe (4) extends into the crystallization tank (6) after passing through the side wall of the crystallization tank (6), and the axis of the outlet of the second circulation pipe (4) is tangent to the outer circular surface of the crystallization tank (8), so that the wastewater flowing out of the second circulation pipe (4) flows into the crystallization tank (6) tangentially, forming a vortex in the crystallization tank (6); The dense phase lining (802) is made of nylon fabric, and the inner frame layer (801) and outer frame layer (803) are both made of steel woven mesh.

2. The near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that, The inlet of the cooling tower (1) is located at its top, and a water pump (2) is installed on the first circulation pipeline (3).

3. The near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that, The cooling tower (1) is a spray cooling tower.

4. The near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that, The biomass pellets are made of bamboo powder.

5. The near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that, A drain pool (10) is provided outside the crystallization pool (6), and a transfer mechanism (9) for transferring the crystallization tank (8) is provided between the crystallization pool (6) and the drain pool (10).

6. The near-saturated wastewater treatment system based on ordered crystallization according to claim 5, characterized in that, The transfer mechanism (9) includes a slide rail (901) suspended above the crystallization tank (6) and the drain tank (10). A hook (904) is connected to the slider (902) of the slide rail (901), and a hanging ring (11) adapted to the hook (904) is provided on the crystallization tank (8).

7. A near-saturated wastewater treatment system based on ordered crystallization according to claim 6, characterized in that, Two mounting brackets (5) are provided at intervals on the outer sides of the crystallization pool (6) and the drain pool (10), and the slide rail (901) is laterally supported on the two mounting brackets (5).

8. The near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that, A buffer tank (7) is connected to one side of the crystallization pool (6), and the buffer tank (7) is connected to the crystallization pool (6) by pipeline.

9. A method for treating near-saturated wastewater based on ordered crystallization, the method being based on the wastewater treatment system described in any one of claims 1-8, characterized in that, Near-saturated wastewater in the multi-effect evaporation crystallization process is transported to the cooling tower (1). After being cooled and concentrated by the cooling tower (1), the supersaturated wastewater is transported to the crystallization tank (6). The salts in the supersaturated wastewater are induced to crystallize by the biomass particles in the crystallization tank (6), and the concentration of the supersaturated wastewater is reduced. The wastewater with reduced concentration is transported to the cooling tower (1) again for concentration and cooling. The cycle is repeated N times. After the wastewater in the crystallization tank (6) is reduced to the target concentration, it is discharged from the crystallization tank (6).

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