A step-by-step desalination device for reclaimed water reuse

Abstract

The utility model relates to water treatment technical field, concretely relates to a kind of water reuse device of stepped desalination.The device includes the pretreatment unit, primary desalination unit, secondary desalination unit and water production storage unit connected in turn;Pretreatment unit includes sedimentation tank, the grid of the import end of sedimentation tank and the hollow fiber ultrafiltration membrane of the export end of sedimentation tank;Primary desalination unit includes the electrodialysis device communicated with the export end of sedimentation tank;Secondary desalination unit includes the security filter communicated with the export end of electrodialysis device, and the inside of security filter is sequentially provided with roll type nanofiltration membrane and roll type reverse osmosis membrane along its water flow direction.The stepped desalination process is used, through the step-by-step processing of primary desalination unit and secondary desalination unit, can gradually reduce the salt content in water, effectively remove a variety of salt and organic matter, heavy metal ions and other pollutants, greatly improve desalination efficiency, ensure that effluent quality is stable, meet different reuse scene needs.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology, specifically to a stepped desalination and greywater reuse device. Background Technology

[0002] With the global water shortage becoming increasingly severe, greywater reuse, as an efficient water recycling method, has become a key means to alleviate the pressure on urban and industrial water use. Among them, desalination technology, as the core link in greywater reuse treatment, directly determines whether the effluent quality can meet the needs of different scenarios such as agricultural irrigation, industrial production, and municipal miscellaneous uses, and therefore has received widespread attention in the industry.

[0003] In existing technologies, desalination processes in greywater reuse systems are mostly single or two-stage treatments. Single-stage desalination processes often only treat specific types of salts, resulting in limited desalination efficiency and an inability to effectively remove multiple salts from the water. This leads to a persistently high salinity in the treated greywater, failing to meet the low salinity requirements of industrial production. While two-stage desalination processes improve desalination efficiency to some extent, their design limitations make them less adaptable to fluctuations in influent water quality. When significant changes occur in the salinity and pollutant composition of the influent, the treatment effect becomes noticeably unstable, leading to large fluctuations in effluent quality and impacting reuse efficiency. Utility Model Content

[0004] The purpose of this utility model is to overcome the shortcomings of the prior art and provide a stepped desalination and reclaimed water device, which aims to solve the problems mentioned in the background art, such as the limited desalination efficiency of the existing single desalination process, the inability to effectively remove multiple salts, and the poor adaptability of the two-stage desalination process to fluctuations in influent water quality and unstable effluent water quality.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows: This utility model provides a stepped desalination water reuse device, which includes a pretreatment unit (1), a primary desalination unit (2), a secondary desalination unit (3), a product water storage unit (4), and a base (5) connected in sequence. The base (5) is in the shape of a five-step ladder; The pretreatment unit (1) includes a sedimentation tank (11), a grid (12) disposed at the inlet end of the sedimentation tank (11), and a hollow fiber ultrafiltration membrane (13) disposed at the outlet end of the sedimentation tank (11). The sedimentation tank (11) is located on the highest step of the base (5). The primary desalination unit (2) includes an electrodialysis unit (21) connected to the outlet end of the sedimentation tank (11) and electrodes installed at both ends of the electrodialysis unit (21). The electrodialysis unit (21) is located on the second-highest step of the base (5). The secondary desalination unit (3) includes a security filter (31) connected to the outlet end of the electrodialysis unit (21). Inside the security filter (31) along its water flow direction, spiral nanofiltration membrane (32) and spiral reverse osmosis membrane (33) are arranged in sequence. The security filter (31) is located on the second-lowest step of the base (5). The water production storage unit (4) includes a stainless steel water tank (41), a liquid level sensor installed in the water tank (41), and a water pump (42) installed on the water tank (41) and connected to the water tank (41). The stainless steel water tank (41) is located on the lowest step of the base (5).

[0006] Optionally, the sedimentation tank (11) is an inclined tube sedimentation tank with an inclined tube length of 1 to 1.5 m and an inclination angle of 60°.

[0007] Optionally, the grille (12) is made of stainless steel and the spacing between the grille bars is 1 to 5 mm.

[0008] Optionally, the electrodialysis unit (21) consists of multiple alternating cation exchange membranes and anion exchange membranes, and the electrodes are titanium-coated ruthenium electrodes.

[0009] Optionally, the electrode chamber of the electrodialysis unit (21) is equipped with an electrode water pipe for removing gas and concentrated water generated by the electrode reaction, and the electrode water pipe is equipped with a valve.

[0010] Optionally, an intermediate water tank (34) is provided at the outlet end of the electrodialysis unit (21) and the inlet end of the security filter (31), and the intermediate water tank (34) is located on the third step of the base (5).

[0011] Optionally, a high-pressure pump (35) is installed at the inlet end of the security filter (31). Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a frontal sectional view of the structure of this utility model.

[0014] Figure descriptions: 1. Pretreatment unit; 11. Sedimentation tank; 12. Bar screen; 13. Hollow fiber ultrafiltration membrane; 2. Primary desalination unit; 21. Electrodialysis unit; 3. Secondary desalination unit; 31. Security filter; 32. Spiral wound nanofiltration membrane; 33. Spiral wound reverse osmosis membrane; 34. Intermediate water tank; 35. High-pressure pump; 4. Product water storage unit; 41. Water storage tank; 42. Water pump. Detailed Implementation

[0015] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0016] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0017] refer to Figure 1 and 2 This utility model provides a stepped desalination greywater reuse device, characterized in that it includes a pretreatment unit 1, a primary desalination unit 2, a secondary desalination unit 3, a product water storage unit 4, and a base 5 connected in sequence. The base 5 is in the shape of a five-tiered staircase; The pretreatment unit 1 includes a sedimentation tank 11, a grid 12 disposed at the inlet end of the sedimentation tank 11, and a hollow fiber ultrafiltration membrane 13 disposed at the outlet end of the sedimentation tank 11. The sedimentation tank 11 is located on the highest step of the base 5. The primary desalination unit 2 includes an electrodialysis unit 21 connected to the outlet end of the sedimentation tank 11 and electrodes installed at both ends of the electrodialysis unit 21. The electrodialysis unit 21 is located on the second-highest step of the base 5. The secondary desalination unit 3 includes a security filter 31 connected to the outlet end of the electrodialysis unit 21. Inside the security filter 31, a spiral nanofiltration membrane 32 and a spiral reverse osmosis membrane 33 are sequentially arranged along the water flow direction. The security filter 31 is located on the second lowest step of the base 5. The water production storage unit 4 includes a stainless steel water tank 41, a liquid level sensor installed in the water tank 41, and a water pump 42 installed on and connected to the water tank 41. The stainless steel water tank 41 is located on the lowest step of the base 5.

[0018] In one possible implementation, the sedimentation tank 11 is an inclined tube sedimentation tank with an inclined tube length of 1-1.5m and an inclination angle of 60°. The design of the inclined tube length and inclination angle increases the sedimentation area of ​​the sedimentation tank 11, shortens the particle settling distance, accelerates the sedimentation speed, improves the removal efficiency of suspended solids in the water, and achieves good sedimentation effect in a relatively small area. It has strong treatment capacity, produces clearer effluent, and reduces the burden on subsequent treatment units. After the reclaimed water enters the inclined tube sedimentation tank 11, the water flows inside the inclined tube. The suspended solids in the water settle under the action of gravity. The inclination angle of the inclined tube causes the settled particles to slide down the inclined tube to the bottom of the tank and be discharged through the sludge removal device. The clear water is collected from the top of the inclined tube and flows out, thereby achieving solid-liquid separation.

[0019] In one possible implementation, the screen 12 is made of stainless steel with a bar spacing of 1–5 mm. Stainless steel has good corrosion resistance and strength, extending the service life of the screen 12 and enabling it to adapt to the complex water quality environment of greywater. The bar spacing of 1–5 mm effectively intercepts larger suspended impurities in the water, such as tree branches and plastic fragments, preventing these impurities from entering subsequent treatment units, avoiding equipment blockage or damage, and ensuring the normal operation of subsequent treatment processes. Before entering the sedimentation tank 11, the greywater flows through the screen 12. The gaps formed by the bar spacing block impurities larger than the gaps from passing through. The impurities are intercepted and cleaned periodically, and the filtered water enters the sedimentation tank 11 for further treatment.

[0020] In one possible implementation, the electrodialysis unit 21 consists of multiple alternating cation exchange membranes and anion exchange membranes. The electrodes are titanium-coated ruthenium electrodes. The alternating arrangement of cation and anion exchange membranes efficiently and selectively migrates cations and anions in the water, improving desalination efficiency. The titanium-coated ruthenium electrodes possess excellent conductivity, corrosion resistance, and stability, extending their service life and ensuring long-term stable operation of the electrodialysis unit 21, thus reducing maintenance costs. During operation, the electrodes are connected to a DC power supply. Under the influence of the electric field, cations in the water move towards the cathode and pass through the cation exchange membrane, while anions move towards the anode and pass through the anion exchange membrane. This causes salts in the desalination chamber to migrate to the concentrate chamber, achieving water desalination. The titanium-coated ruthenium electrodes, as the electrode material, stably provide the electric field, ensuring the smooth progress of the ion migration process.

[0021] In one possible implementation, the electrode chamber of the electrodialysis unit 21 is equipped with an electrode water pipe for discharging gases and concentrates generated during the electrode reaction. A valve is installed on the electrode water pipe to promptly discharge gases such as hydrogen and oxygen generated during the electrode reaction, preventing gas accumulation in the electrode chamber from affecting the electrode conductivity and reaction efficiency. Simultaneously, it discharges concentrate to prevent excessive concentration from affecting the desalination effect and operational stability of the electrodialysis unit 21. The valve controls the flow rate and discharge of the electrode water, facilitating adjustment and maintenance. During the electrochemical reaction, the electrodes generate gases, and a certain amount of concentrate accumulates in the electrode chamber. The electrode water carries these gases and concentrates through the electrode water pipe during its flow. By adjusting the valve opening, the flow rate of the electrode water is controlled, ensuring timely discharge of gases and concentrates, maintaining normal operating conditions of the electrode chamber, and guaranteeing the stable operation of the electrodialysis unit 21.

[0022] In one possible implementation, an intermediate water tank 34 is provided at the outlet end of the electrodialysis unit 21 and the inlet end of the security filter 31. The intermediate water tank 34 is located on the third step of the base 5. The intermediate water tank 34 can play a buffering role, stabilize the water volume and water pressure entering the security filter 31, and avoid the impact of the water fluctuation of the electrodialysis unit 21 on subsequent treatment. The water treated by the electrodialysis unit 21 first enters the intermediate water tank 34 for temporary storage, and then enters the security filter 31 after the water flow is stabilized.

[0023] In one possible implementation, a high-pressure pump 35 is installed at the inlet of the security filter 31. The high-pressure pump 35 provides sufficient high-pressure power to the interior of the security filter 31, ensuring the normal operation of the spiral wound nanofiltration membrane 32 and the spiral wound reverse osmosis membrane 33, improving the filtration efficiency and desalination effect of the membranes, and ensuring that the effluent water quality meets the standards. The high-pressure pump 35 pressurizes the water in the intermediate water tank 34 and sends it into the security filter 31. Under high pressure, the water passes through the spiral wound nanofiltration membrane 32 and the spiral wound reverse osmosis membrane 33. The membranes retain impurities such as salt and organic matter in the water, achieving deep desalination.

[0024] The working principle of this utility model is as follows: The wastewater to be treated first enters the pretreatment unit 1, and then passes through the screen 12 to remove large particulate impurities, the inclined tube sedimentation tank 11 to remove suspended particulate matter, the precision filter to remove fine particles, and the hollow fiber ultrafiltration membrane 13 to remove colloids and macromolecular organic matter, thus completing the pretreatment process and laying the foundation for subsequent desalination treatment.

[0025] The pretreated water enters the first-stage desalination unit 2. In the electrodialysis unit 21, under the action of a DC electric field, cations in the water move towards the cathode and anions move towards the anode. Through the selective permeation of the cation exchange membrane and the anion exchange membrane, cations enter the concentrate chamber and anions also enter the concentrate chamber, thereby removing the salt in the desalination chamber.

[0026] After primary desalination, the water enters the intermediate water tank 34 for buffering. Then, under the action of the high-pressure pump 35, it enters the security filter 31 in the secondary desalination unit 3. The water then passes through the spiral wound nanofiltration membrane 32, which selectively removes salts and organic matter from the water, further removing salts, some organic matter, and heavy metal ions. Next, the water enters the spiral wound reverse osmosis membrane 33. Under the action of the high-pressure pump 35, the spiral wound reverse osmosis membrane 33 can retain almost all salts and pollutants in the water, removing the remaining salts and ensuring the effluent meets reuse standards.

[0027] The treated wastewater that meets the standards is stored in the stainless steel water tank 41 of the water production storage unit 4. When the water level in the water tank 41 reaches a certain height, the wastewater can be transported to the reuse point by the water pump 42.

[0028] The present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A stepped desalination and wastewater reuse device, characterized in that, It includes a pretreatment unit (1), a primary desalination unit (2), a secondary desalination unit (3), a product water storage unit (4), and a base (5) connected in sequence. The base (5) is in the shape of a five-step ladder; The pretreatment unit (1) includes a sedimentation tank (11), a grid (12) disposed at the inlet end of the sedimentation tank (11), and a hollow fiber ultrafiltration membrane (13) disposed at the outlet end of the sedimentation tank (11). The sedimentation tank (11) is located on the highest step of the base (5). The primary desalination unit (2) includes an electrodialysis unit (21) connected to the outlet end of the sedimentation tank (11) and electrodes installed at both ends of the electrodialysis unit (21). The electrodialysis unit (21) is located on the second-highest step of the base (5). The secondary desalination unit (3) includes a security filter (31) connected to the outlet end of the electrodialysis unit (21). Inside the security filter (31) along its water flow direction, spiral nanofiltration membrane (32) and spiral reverse osmosis membrane (33) are arranged in sequence. The security filter (31) is located on the second-lowest step of the base (5). The water production storage unit (4) includes a stainless steel water tank (41), a liquid level sensor installed in the water tank (41), and a water pump (42) installed on the water tank (41) and connected to the water tank (41). The stainless steel water tank (41) is located on the lowest step of the base (5).

2. The stepped desalination and wastewater reuse device according to claim 1, characterized in that, The sedimentation tank (11) is an inclined tube sedimentation tank with an inclined tube length of 1 to 1.5 m and an inclination angle of 60°.

3. The stepped desalination and wastewater reuse device according to claim 1, characterized in that, The grille (12) is made of stainless steel and the spacing between the grille bars is 1 to 5 mm.

4. The stepped desalination and wastewater reuse device according to claim 1, characterized in that, The electrodialysis unit (21) consists of multiple alternating cation exchange membranes and anion exchange membranes, and the electrodes are titanium-coated ruthenium electrodes.

5. The stepped desalination and wastewater reuse device according to claim 1, characterized in that, The electrode chamber of the electrodialysis unit (21) is equipped with an electrode water pipe for removing gas and concentrated water generated by the electrode reaction, and a valve is installed on the electrode water pipe.

6. The stepped desalination and wastewater reuse device according to claim 1, characterized in that, An intermediate water tank (34) is provided at the outlet end of the electrodialysis unit (21) and the inlet end of the security filter (31), and the intermediate water tank (34) is located on the third step of the base (5).

7. The stepped desalination and wastewater reuse device according to claim 6, characterized in that, A high-pressure pump (35) is installed at the inlet end of the security filter (31).

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