Near-saturation-state wastewater treatment system and method based on ordered crystallization

Abstract

The invention discloses a near-saturated wastewater treatment system and method based on ordered crystallization, and relates to the field of industrial wastewater treatment. A first circulating pipeline for conveying wastewater in the crystallizing pond to the cooling tower and a second circulating pipeline for conveying wastewater in the cooling tower to the crystallizing pond are connected between the crystallizing pond and the cooling tower; a crystallization tank capable of being lifted and moved out is placed in the crystallization pond, the tank wall of the crystallization tank is of multiple layers and at least comprises an inner frame layer, a dense-phase lining layer and an outer frame layer which are sequentially arranged from inside to outside, biomass particles are placed in the crystallization tank, and the particle size of the biomass particles is larger than the pore diameter of the dense-phase lining layer. The method is used for solving the technical problems that disordered crystallization is easy to occur and the energy consumption is relatively high when wastewater is treated by a multi-effect evaporative crystallization process.

Description

Technical Field

[0001] The 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 Art

[0002] In the field of wastewater treatment, multi-effect evaporation crystallization is one of the current mainstream treatment processes. It has many advantages, such as relatively mature technology, a wide range of wastewater that can be treated, fast treatment speed, high degree of process automation, and low operating difficulty.

[0003] However, the multi-effect evaporation crystallization process generally requires the use of heating to continuously evaporate and concentrate the wastewater. The wastewater first reaches a near-saturated state, and then continues to heat to concentrate the near-saturated wastewater into a supersaturated state, and continues to heat to achieve crystallization. On the one hand, this evaporation and crystallization method consumes a high amount of steam and electricity, which makes the cost of wastewater treatment high. On the other hand, the salt crystallization of the multi-effect evaporation crystallizer is disordered crystallization with poor controllability. It is especially easy to crystallize in the walls and pipes of the container, causing wall climbing and pipe blockage, affecting the heat transfer efficiency and stability of the equipment, and requires regular cleaning and maintenance; in addition, due to the complex composition of wastewater, it often contains various corrosive substances. Crystallization in the walls and pipes of the container will also cause corrosion of the pipes and containers, causing serious corrosion during the operation of the overall equipment and a short lifespan. This requires that the standards must be raised when selecting equipment materials, increasing the investment cost of the equipment. Summary of the invention

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

[0005] In order to solve the above technical problems, the specific scheme adopted by the present invention is: a near-saturated wastewater treatment system based on ordered crystallization, comprising a cooling tower and a crystallization pool,

[0006] A first circulation pipeline for conveying wastewater in the crystallization pool to the cooling tower and a second circulation pipeline for conveying wastewater in the cooling tower to the crystallization pool are connected between the crystallization pool and the cooling tower;

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

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

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

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

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

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

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

[0014] As a further optimization of the above technical solution, two mounting frames are arranged at intervals on the outer sides of the crystallization tank and the drainage tank, and the slide rails are laterally supported on the two mounting frames.

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

[0016] A method for treating near-saturated wastewater based on ordered crystallization. The method is based on the above-mentioned wastewater treatment system. The near-saturated wastewater in the multi-effect evaporation crystallization process is transported to a cooling tower. The supersaturated wastewater after cooling and concentration in the cooling tower is transported to a crystallization pool. The salts in the supersaturated wastewater are induced to crystallize through biomass particles in the crystallization pool. The concentration of the supersaturated wastewater is reduced. The wastewater with reduced concentration is transported to the cooling tower again for concentration and cooling. The cycle is repeated N times. After the wastewater in the crystallization pool is reduced to a target concentration, it is discharged out of the crystallization pool.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a crystallization pool and a crystallization tank in the crystallization pool, and places biomass particles in the crystallization tank, and uses the biomass particles to induce crystallization of supersaturated wastewater. Salt minerals in the supersaturated wastewater crystallize on the biomass particles, and the salts are crystallized in an orderly manner in a designated area, which can avoid pipeline blockage and wall climbing caused by chaotic crystallization of salts, and ensure the stability of the equipment, strong controllability, and simple operation.

[0019] The present invention can make various salts be concentratedly crystallized in a designated area, which is convenient for cleaning and collection. The corrosion degree of the equipment is small during operation, which greatly increases the service life and reduces the cost.

[0020] The present invention adopts a cooling tower to cool the wastewater to be treated. When the wastewater passes through the cooling tower, on the one hand, water evaporates to achieve the concentration of the nearly 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. The evaporation concentration and the solubility change together realize the conversion of nearly saturated brine to supersaturated brine, which is convenient for inducing crystallization in the induced crystallization device.

[0021] The cooling tower concentrates the unsaturated salts in the nearly saturated wastewater through natural evaporation. No additional heating device is required, which can avoid the energy consumption and carbon dioxide production caused by the heating device. It is environmentally friendly and saves resources. The entire concentration process is achieved at a lower temperature. Therefore, this system can achieve crystallization at a lower energy input, thereby reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the three-dimensional structure of the wastewater treatment system in the present invention;

[0023] Figure 2 is a side view schematic diagram of the wastewater treatment system of the present invention;

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

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

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

[0027] Figure 6 for Figure 5 The 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 is a schematic top view of a wastewater treatment system of the present invention;

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

[0031] Fig.10 for Fig. 9 The enlarged view of point D in the middle;

[0032] Fig.11 for Fig. 9 Enlarged view of point E in the middle;

[0033] Figure numerals: 1, cooling tower, 101, tower base, 102, liquid accumulation tank, 103, air inlet channel, 104, tower body, 105, spray mechanism, 1051, spray pipe, 1052, nozzle, 106, bionic lung mist capture layer, 2, water delivery pump, 3, first circulation pipeline, 4, second circulation pipeline, 5, mounting frame, 501, support rod, 502, cross bar, 503, diagonal support, 504, roller , 6. crystallization pool, 601. support table, 602. support bar, 7. buffer tank, 8. crystallization tank, 801. inner frame layer, 802. dense phase lining layer, 803. outer frame layer, 804. mounting table, 9. transfer mechanism, 901. slide rail, 902. slider, 903. pull rope, 904. hook, 10. drain pool, 11. hanging ring, 12. third circulation pipeline, 13. fourth circulation pipeline. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further elaborated in detail below in conjunction with specific embodiments. The parts of the present invention that are not described and disclosed in detail in the following embodiments should be understood as the prior art known or should be known to 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, comprising a cooling tower 1 and a crystallization pool 6, wherein the crystallization pool 6 and the cooling tower 1 are connected with a first circulation pipeline 3 for conveying wastewater in the crystallization pool 6 to the cooling tower 1 and a second circulation pipeline 4 for conveying wastewater in the cooling tower 1 to the crystallization pool 6.

[0036] The cooling tower 1 is a naturally ventilated spray cooling tower, and its structure is the prior art. After the liquid to be cooled is transported to the upper part of the tower body, it is sprayed in the tower through the water inlet opened at the upper part of the tower body 104. At the same time, an air inlet channel for natural wind to enter is opened on the tower wall, and the natural wind is used to cool the liquid in 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 accumulation tank 102 arranged in the tower body 104 and located at the bottom of the tower body 104, and a spray mechanism 105 arranged in the tower body 104 and located above the liquid accumulation 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 arranged in 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 waste water in the crystallization pool 6 passes through the first circulation pipeline 3 and the spray pipe 1051, and is sprayed into the tower body 104 through the nozzle 1052;

[0038] A bionic lung fog-catching layer 106 for intercepting fog droplets is designed above the tower body 104. The bionic lung fog-catching layer 106 includes a multi-layer fog-catching net arranged at intervals and a polyhedral environmental protection ball stacking filler arranged on the fog-catching net. The airflow needs to pass through more than 120 deflection curves of the layer before entering the atmosphere. This structure can prevent 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 provided on the bionic lung fog-catching layer 106, which can be cleaned online. The water inlet end of the cleaning water pipe is connected to the first circulation pipeline 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 cleaning water source separately.

[0040] A plurality of air inlet channels 103 are provided on the side wall of the tower body 104, and natural wind enters the tower body 104 through the air inlet channels 103 to cool the wastewater solution in the tower body 104. The cooled wastewater is collected in the liquid accumulation tank 102, and the second circulation pipeline 4 is connected to the liquid accumulation tank 102 to transport the wastewater in the liquid accumulation tank 102 to the crystallization pool 6.

[0041] The spray mechanism 105 is located at the upper part of the tower body 104 and higher than the crystallization pool 6 , so a water delivery pump 2 is provided 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 accumulating tank 102 is arranged on the tower base 101 at the bottom of the tower body 104. The arrangement position of the liquid accumulating tank 102 is higher than the crystallization pool 6. The waste liquid in the liquid accumulating tank 102 can be transported to the crystallization pool 6 along the second circulation pipeline 4 in an overflow manner. It can be understood that in order to facilitate the flow of waste water between the cooling tower 1 and the crystallization pool 8, a water delivery pump can also be arranged on the second circulation pipeline 4.

[0043] The crystallization pool 6 is provided with an external discharge pipeline (not shown in the figure), and a commercially available water quality detector is installed on the external discharge pipeline. When the water quality detector detects that the water quality reaches the discharge standard, the external discharge pipeline is opened and the treated wastewater flows out of the crystallization pool 6.

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

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

[0046] The wall of the crystallization tank 8 is multi-layered, including at least an inner frame layer 801, a dense lining layer 802 and an outer frame layer 803 arranged in sequence from the inside to the outside. In this embodiment, the wall of the crystallization tank 8 is three-layered, including a tank side wall and a tank bottom wall, and both the tank side wall and the tank bottom wall include an inner frame layer 801, a dense lining layer 802 and an outer frame layer 803, and both the inner frame layer 801 and the outer frame layer 803 are steel woven meshes, and the dense lining layer 802 is nylon cloth. The meshes of the inner frame layer 801 and the outer frame layer 803 are larger than the aperture of the dense lining layer 802. Since the dense lining layer 802 is made of a flexible material, the inner frame layer 801 and the outer frame layer 803 can provide support for the dense lining layer 802.

[0047] A support bar 602 is provided at the bottom of the crystallization pool 6. When the crystallization tank 8 is placed in the crystallization pool 6, the support bar 602 is supported on the bottom of the crystallization tank 8 so that a gap is left between the bottom of the crystallization tank 8 and the bottom of the crystallization pool 6; an inwardly convex annular support platform 601 is circumferentially provided on the inner side of the side wall of the crystallization pool 6, and an outwardly convex 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 pool 6, the support platform 601 is supported below the mounting platform 804, so that a gap is left between the side wall of the crystallization tank 8 and the side wall of the crystallization pool 6, and the annular support platform 601 can be used to position the crystallization tank 8, thereby avoiding the crystallization tank 8 from being deflected in the crystallization pool 6 or shaking due to the impact of water flow.

[0048] Biomass particles are arranged in the crystallization tank 8, and the particle size of the biomass particles is larger than the pore size of the dense lining layer 802. The biomass particles are material particles with a large specific surface area. The biomass particles in this embodiment are bamboo powder, and the particle size of the bamboo powder is 40-60 mesh, which is obtained by crushing bamboo. The bamboo powder fiber is used as a crystal nucleus to induce crystallization of the salts in the waste liquid that have reached supersaturation concentration, so that the salts are crystallized in the crystallization tank 8.

[0049] like Figure 1 , 10As shown, a draining tank 10 is provided outside the crystallization tank 6, and the cross section of the draining tank 10 is circular. The size of the draining tank 10 is the same as or larger than that of the crystallization tank 6, so that the crystallization tank 8 can be transferred to the draining tank 10, and the crystallized salt in the crystallization tank 8 is drained. The draining tank 10 is connected to a third circulation pipeline 12, and the third circulation pipeline 12 is connected in parallel to the first circulation pipeline 3, and the connection point between the third circulation pipeline 12 and the first circulation pipeline 3 is located upstream of the delivery water pump 2, so that the wastewater falling into the draining tank 10 is pumped into the cooling tower 1 along with the first circulation pipeline 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 drainage tank 10. The transfer mechanism 9 includes a slide rail 901 suspended above the crystallization tank 6 and the drainage 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 frames 5 are provided at intervals on the outer sides of the crystallization tank 6 and the drainage tank 10, the slide rail 901 is laterally supported on the two mounting frames 5, and the two mounting frames 5 are respectively fixed at both ends of the slide rail 901, and the specific fixing method is the existing technology, and welding or bolt connection is acceptable.

[0051] Combination Figure 7 As shown, each mounting frame 5 includes a vertical support rod 501 and a cross 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 cross bar 502, and an oblique brace 503 is connected between the support rod 501 and the cross bar 502, one end of the oblique brace 503 is fixed to the end of the cross bar 502, and the other end is fixed to the rod body of the support rod 501. Two rollers 504 are arranged at intervals at the bottom of the cross bar 502, so that the transfer mechanism 9 can move when pushed by an external force, and the position of the transfer mechanism 9 can be adjusted according to the actual application scenario.

[0052] The two mounting frames 5 have the same height, and the slide rail 901 is arranged horizontally, and a slider 902 capable of sliding thereon is provided on the slide rail 901. Specifically, a pulley is rotatably mounted on the slider 902, and a slideway for the pulley to slide thereon is provided on the slide rail 901, and the slide of the pulley on the slideway drives the slider 902 to slide on the slide rail 901. The installation of the slider 902 on the slide rail 901 can also adopt other methods of the prior art, as long as it can ensure that the slider 902 moves on the slide rail 901, which will not be described in detail 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. A pull rope 903 is provided on the electric hoist, and a hook 904 is provided at the end of the pull rope 903. A hanging ring 11 is provided on the upper surface of the mounting platform 804 of the crystallization tank 8. The number of the hanging rings 11 is multiple and is distributed circumferentially along the hanging rings 11. In this embodiment, the number of the hanging rings 11 is three. The hook 904 is hung on the hanging ring 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, and 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 drainage pool 10.

[0054] In order to facilitate the hook 904 to lift the crystallization tank 8, the transfer mechanism 9 of the present invention is equipped with an auxiliary chain (not shown in the figure), which includes a main chain and three branch chains connected to the end of the main rope. A hook is set at the end of each branch chain, and a hook is set at the end of the main chain away from the branch chain. When in use, the hook on each branch chain is connected to a hanging ring 11, and the hook of the main rope is connected to the hook 904, so that the crystallization tank 8 is lifted. The lengths of the three branch chains are consistent, which is convenient for maintaining the stability of the crystallization tank 8.

[0055] In the process of treating wastewater, 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 salt crystals after draining are sent to the subsequent collection device for corresponding treatment. In this embodiment, the slide 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 slider 902 can be remotely controlled to move to realize the transfer of the crystallization tank 8.

[0056] One side of the crystallization pool 6 is connected to a buffer tank 7, which is connected to the crystallization pool 6 through a 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 wastewater to be treated in the crystallization pool 6 decreases, it is transported from the buffer tank 7 to the crystallization pool 6.

[0057] The present invention also discloses a method for treating near-saturated wastewater based on ordered crystallization. The method adopts the above-mentioned wastewater treatment system, and the method comprises the following steps: the near-saturated wastewater in the multi-effect evaporation crystallization process is transported to a cooling tower 1, the supersaturated wastewater after cooling and concentration by the cooling tower 1 is transported to a crystallization pool 6, the salts in the supersaturated wastewater are induced to crystallize through biomass particles in the crystallization pool 6, the concentration of the supersaturated wastewater is reduced, and the wastewater with reduced concentration is transported to the cooling tower 1 again for concentration and cooling, and the cycle is repeated N times, where N is a natural number not less than 1, and the wastewater in the crystallization pool 6 is discharged from the crystallization pool 6 after it is reduced to a target concentration.

[0058] Specifically, during the use of the method, the nearly saturated wastewater in the multi-effect evaporation crystallization process is first transported to the crystallization pool 6 as a mother liquor, and then biomass particles are added to the mother liquor; the nearly saturated wastewater is continued to be input into the crystallization pool 6, and at the same time, the water delivery pump 2 on the first circulation pipeline 3 is turned on to pump the wastewater in the crystallization pool 6 into the cooling tower 1. The wastewater cooled by the cooling tower 1 falls into the liquid accumulation tank 102 at the bottom of the cooling tower 1, and then is sent to the crystallization pool 6 through the second circulation pipeline 4. The wastewater cooled and concentrated by the cooling tower 1 has the dual effects of evaporation and cooling. On the one hand, the water evaporates to make the solution The concentration increases, and on the other hand, the solubility of salts decreases after cooling. Therefore, after being concentrated by the cooling tower 1, the nearly saturated wastewater becomes supersaturated wastewater, and the supersaturated wastewater is transported to the crystallization pool 6 again. The salt minerals in the supersaturated wastewater crystallize on the biomass particles, and the salts are crystallized in an orderly manner in the designated area. After the salts are crystallized, the concentration of the wastewater in the crystallization pool 6 decreases. At this time, the wastewater is pumped into the cooling tower 1 again through the first circulation pipeline 3. This cycle is repeated N times. When the wastewater in the crystallization pool 6 is reduced to the target concentration and the water quality detector detects that the water quality is qualified, the wastewater is discharged through the external discharge pipeline. In this process, when there is too much wastewater in the crystallization pool 6, the valve set on the fourth circulation pipeline 13 is opened, and the wastewater is transported to the buffer tank 7 through the fourth circulation pipeline 13 for buffering. When the wastewater to be treated in the crystallization pool 6 is reduced, it is sent from the buffer tank 7 to the crystallization pool 6.

[0059] The near-saturated wastewater treatment system and method based on ordered crystallization of the present invention can be used not only to induce crystallization of salts in industrial wastewater, but also to perform crystallization treatment on solutions containing calcium and magnesium ions to separate and recover the calcium and magnesium ions. The prior art generally uses a reverse osmosis membrane to treat calcium and magnesium ions, but calcium and magnesium ions are easily attached to the reverse osmosis membrane, making separation difficult. By using the treatment system and method of the present invention, calcium and magnesium ions are induced to crystallize in a crystallization tank, so that calcium and magnesium ions can be effectively separated.

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

[0061] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to 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: It comprises a cooling tower (1) and a crystallization pool (6), A first circulation pipeline (3) for conveying wastewater in the crystallization pool (6) to the cooling tower (1) and a second circulation pipeline (4) for conveying wastewater in the cooling tower (1) to the crystallization pool (6) are connected between the crystallization pool (6) and the cooling tower (1); A crystallization tank (8) capable of being lifted and removed is placed in the crystallization pool (6); the tank wall of the crystallization tank (8) is multi-layered, comprising at least an inner frame layer (801), a dense lining layer (802) and an outer frame layer (803) arranged in sequence 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 lining layer (802).

2. A near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that: The water inlet of the cooling tower (1) is located at the upper part thereof, and a water delivery pump (2) is arranged on the first circulation pipeline (3).

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

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

5. A near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that: The dense lining layer (802) is made of nylon cloth, and the inner frame layer (801) and the outer frame layer (803) are both made of steel woven mesh.

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

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

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

9. A near-saturated wastewater treatment system based on ordered crystallization according to claim 1, characterized in that: One side of the crystallization pool (6) is connected to a buffer tank (7), and the buffer tank (7) is connected to the crystallization pool (6) through a pipeline.

10. A method for treating near-saturated wastewater based on ordered crystallization, the method being based on the wastewater treatment system according to any one of claims 1 to 9, characterized in that: In the multi-effect evaporation crystallization process, nearly saturated wastewater is transported to a cooling tower (1), and supersaturated wastewater after being cooled and concentrated by the cooling tower (1) is transported to a crystallization pool (6). Salts in the supersaturated wastewater are induced to crystallize by biomass particles in the crystallization pool (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, and the cycle is repeated N times. After the wastewater in the crystallization pool (6) is reduced to a target concentration, it is discharged from the crystallization pool (6).

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