A method and device for advanced treatment of reverse osmosis product water

Abstract

The application discloses a method and device for deep treatment of reverse osmosis water, and relates to the technical field of industrial high-purity water treatment. The application adopts a treatment system formed by sequentially connecting an electric mixed bed and a negative bed in series, wherein the electric mixed bed is without an ion exchange membrane structure, is filled with mixed anion and cation resins, and is used for removing residual salts, carbon dioxide and part of silicon compounds in the reverse osmosis water; the negative bed is filled with strong alkaline anion exchange resins, and is used for removing the residual silicon compounds after the treatment of the electric mixed bed, so that the final water conductivity and the silicon dioxide can be stably up to the standard. An intermediate liquid discharge device is arranged between the electric mixed bed and the negative bed, and is used for discharging waste alkali liquid and cleaning water in the regeneration and cleaning processes of the negative bed. The application integrates the advantages of the electric mixed bed, i.e. low cost and high water recovery rate, and the negative bed, i.e. high silicon removal efficiency, can significantly relax the requirement for the silicon content of the reverse osmosis water, widen the application range of the electric mixed bed, and greatly prolong the service life of the reverse osmosis membrane.

Description

Technical Field

[0001] This invention relates to the field of industrial high-purity water treatment technology, specifically to a method and apparatus for deep treatment of reverse osmosis permeate. Background Technology

[0002] In industries such as power, chemical, and pharmaceutical, high-purity water is widely used as a key production medium, and its purity directly affects the stability of production processes, product quality, and equipment lifespan. Currently, the mainstream high-purity water treatment process is a combination of "pretreatment + reverse osmosis + advanced treatment," in which the advanced treatment unit mostly adopts electrodeionization (EDI), traditional mixed ion exchange beds (mixed beds), or electro-mixed beds, forming a mature water purification chain.

[0003] In the above process system, the reverse osmosis unit plays a core pretreatment role, mainly removing most of the salts, most of the silicon compounds, some organic matter and colloidal impurities from the raw water, providing water quality assurance for subsequent advanced treatment; while EDI, mixed bed or electro-mixed bed, as advanced treatment links, have the core function of further removing residual trace salts, carbon dioxide and silicon compounds from the water, ultimately achieving the water quality requirements of high purity water.

[0004] However, existing processes have significant technical drawbacks: the performance degradation of reverse osmosis membranes exhibits differentiated characteristics. Their desalination efficiency decreases relatively slowly with increasing usage time, still meeting the pretreatment requirements for salt content in subsequent advanced treatment processes after long-term operation. However, their silicon removal efficiency decays relatively quickly. With prolonged operation, the reverse osmosis membrane's ability to retain silicon compounds decreases significantly, leading to a substantial increase in the silicon content of the effluent. Since EDI and electro-mixed bed technologies have limited silicon removal capabilities, they cannot effectively treat reverse osmosis permeate with high silicon content. Excessively high silicon content can severely adversely affect subsequent advanced treatment processes, potentially causing the advanced treatment unit to fail and impacting the final effluent quality.

[0005] When the silica content in the reverse osmosis permeate exceeds the tolerance threshold of subsequent processes, the reverse osmosis membrane must be replaced to ensure water quality meets standards, even if the membrane element's desalination performance remains usable. However, reverse osmosis membranes are expensive, and frequent replacements significantly increase maintenance costs and disrupt production continuity. It's important to note that the decline in silica removal efficiency of reverse osmosis membranes is an objective phenomenon determined by their inherent material and operating characteristics, and is difficult to fundamentally change. Therefore, optimizing subsequent advanced treatment processes to improve the overall silica removal capacity of the system, ensuring that the final effluent silica content meets requirements even with declining silica removal efficiency and increased silica content, thereby extending the membrane's lifespan and reducing maintenance costs, has become a critical technological bottleneck that urgently needs to be overcome in the field of high-purity water production, especially in advanced treatment using EDI / electro-mixed-bed equipment. Summary of the Invention

[0006] In order to overcome the problems existing in the background art, the present invention provides a method and apparatus for deep desalination and desiliconization combining an electro-mixed bed and anion exchange bed, for deep treatment of reverse osmosis permeate.

[0007] The technical solution of the present invention is as follows: A method for deep treatment of reverse osmosis permeate employs a treatment system consisting of an electro-mixed bed and an anion exchange bed connected in series, with an intermediate drainage device between the electro-mixed bed and the anion exchange bed. During treatment, the reverse osmosis permeate flows from top to bottom through the electro-mixed bed unit, the intermediate drainage device, and the anion exchange bed unit. The electro-mixed bed is used to remove residual salts, carbon dioxide, and some silicon compounds after reverse osmosis treatment, while the anion exchange bed is used to remove residual silicon compounds after electro-mixed bed treatment, ensuring that the conductivity and silica of the final permeate can stably meet the standards.

[0008] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0009] Optionally, the electric mixed bed is periodically electro-regenerated according to a preset cycle, while the anion bed is chemically regenerated based on silicon content triggering. That is, at the end of the electric mixed bed treatment cycle, if the silicon content of the anion bed effluent reaches a preset threshold, both the anion bed and the electric mixed bed are regenerated; otherwise, only the electric mixed bed is regenerated.

[0010] Optionally, the following operation may be performed only during electric mixed bed regeneration: (1) Purified water is introduced from the bottom of the anion bed, flows through the anion bed and the intermediate drainage device, and then flows into the electric mixed bed; the DC power supply is turned on to drive the electric regeneration of the resin layer of the electric mixed bed, and the regenerated concentrate is discharged from the top and sent to the pre-reverse osmosis for recycling. (2) After regeneration, turn off the DC power supply and keep the water flow constant to clean the electro-mixed bed resin layer.

[0011] Optionally, when both the anion bed and the electro-mixed bed are regenerated, the operation is as follows: (1) Chemical regeneration of the anion bed: Purified water is introduced from the bottom of the anion bed upwards, and sodium hydroxide solution is added to form a 0.1%-1.0% dilute alkali solution, which is regenerated at a flow rate of 5-10 m / h; at the same time, a small flow of reverse osmosis permeate is introduced from the top of the electric mixed bed to prevent waste alkali solution from entering the resin layer of the electric mixed bed. The mixed solution is discharged through the intermediate drain device and used to adjust the pH value of the pre-reverse osmosis feed water. (2) Anion bed cleaning: Stop adding chemicals, keep the water flow constant, clean the anion bed, and discharge the water along the above path. This is also used to adjust the pH value of the pre-reverse osmosis feed water. (3) Continue cleaning of the anion bed / regeneration of the electro-mixed bed: The anion bed is cleaned with purified water. The anion bed cleaning water flows into the electro-mixed bed from bottom to top. At the same time, the DC power supply is turned on to drive the regeneration of the electro-mixed bed resin layer. The electro-regeneration concentrate is discharged from the top of the electro-mixed bed and sent to the pre-reverse osmosis for recycling. (4) Synchronous cleaning: Turn off the power, keep the water flow constant, and simultaneously clean the anion bed and the electro-mixed bed resin layer. The cleaning effluent is also sent to the pre-reverse osmosis system for recycling.

[0012] Optionally, the processing flow rate is 60~120m / h.

[0013] Optionally, during electro-regeneration of the electric mixed bed, the regeneration current density is 120~200A / m. 2 The average voltage is 300~500V.

[0014] Optionally, the regeneration and cleaning flow rate of the electric mixed bed is 30~60 m / h; Optionally, the processing time in each electric mixed bed operation cycle is 100~250 minutes, and the regeneration and cleaning times are 15~20 minutes and 1~3 minutes, respectively.

[0015] This application also provides a deep processing device for implementing the deep processing method, which adopts an integrated structure and includes, from top to bottom, an electro-mixed bed, an intermediate drainage device and an anion bed, which are connected in a sealed manner to form a whole.

[0016] Optionally, the electro-mixed bed includes a cover plate, an upper chamber, a first water distribution assembly, a second water distribution assembly, an anode, and a cathode. The cover plate is rectangular with a first reinforcing rib at the top and an upper pipe interface at the center. The upper chamber is located below the cover plate and is sealed to the cover plate. It is open at both the top and bottom, and its lower end is sealed to the intermediate drainage device. It has a second reinforcing rib on the outside and is rectangular in shape inside. The first water distribution assembly and the second water distribution assembly are located at the upper and lower ends of the upper chamber, respectively. The anode and cathode are respectively installed in close contact with two opposite inner sidewalls of the upper chamber. The cavity formed by the anode, cathode, the other two inner sidewalls of the upper chamber, and the first and second water distribution assemblies is filled with a mixture of anion and cathode resin to form an electro-mixed bed resin layer.

[0017] Optionally, the intermediate drainage device has a water collection hole at its center and an intermediate drainage interface on one of its edge sides for discharging waste liquid from the anion bed regeneration and cleaning water.

[0018] Optionally, the intermediate drainage device adopts a clamp-like structure, the water collection hole axially penetrates the center of the clamp-like structure, and the interior of the clamp-like structure is provided with a drainage channel connecting the water collection hole and the intermediate drainage interface.

[0019] Optionally, the anion exchange bed includes a lower chamber, a third water distribution assembly, and a fourth water distribution assembly. The upper end of the lower chamber is open and sealed to the intermediate drainage device. The lower end has a base plate with a central lower pipe interface. The interior is rectangular, and the outer wall has a third reinforcing rib and a support foot. The lower side of the base plate has a fourth reinforcing rib. The third water distribution assembly and the fourth water distribution assembly are located at the upper and lower ends of the lower chamber, respectively. Strong alkaline anion exchange resin is filled between them to form an anion exchange bed resin layer.

[0020] Optionally, the outer edges of the upper and lower housings are flange structures; the outer edges of the cover plate and the intermediate drain device are both provided with matching flange holes; a first sealing gasket is sandwiched between the lower side of the cover plate and the upper end of the upper housing, and the connection is secured by a first bolt group; a second sealing gasket is sandwiched between the lower end of the upper housing and the upper side of the intermediate drain device, and a third sealing gasket is sandwiched between the lower side of the intermediate drain device and the upper end of the lower housing, and the connections are secured by a second bolt group.

[0021] Optionally, the filling height of the electric mixed bed resin layer is 50~80cm.

[0022] Optionally, the filling height of the anion bed resin layer is 30~50cm.

[0023] Optionally, each of the two opposite side walls of the upper housing is provided with an anode terminal through hole and a cathode terminal through hole for passing through the corresponding terminals. The anode terminals and cathode terminals are assembled through the corresponding through holes; the anode and cathode are electrically connected to the corresponding terminals.

[0024] Optionally, the inner walls of the upper and lower housings, as well as the through holes of the anode and cathode terminals, are all made of insulating material, or the entire housing is made of insulating material to achieve insulation isolation between the inside and outside of the housing; the back of the anode and cathode is sealed with insulating glue between the inner wall of the upper housing, between the anode terminals and the anode terminals, and between the cathode terminals and the cathode terminals.

[0025] Optionally, the anodes are electrically connected to each other and the cathodes are electrically connected to each other by direct electric welding.

[0026] Optionally, the wiring terminals are secured to the outer wall of the enclosure with nuts and washers.

[0027] Optionally, the second and third water distribution components are fixedly connected to the top and bottom surfaces of the intermediate drainage device, respectively; the first water distribution component is fixedly connected to the bottom surface of the cover plate, and the fourth water distribution component is fixedly connected to the top surface of the base plate.

[0028] Optionally, the first, second, third, and fourth water distribution components each include a slit plate for intercepting resin, a frame, and 10-30 cylindrical support members with a diameter of 20-30mm and a central bolt hole. These support members are respectively tightly fixed to the inner side of the cover plate, the upper and lower sides of the intermediate drainage device, and the inner side of the base plate using high-strength insulating bolts or acid and alkali resistant waterproof sealant.

[0029] Compared with the prior art, this application has the following beneficial effects: This application integrates the advantages of "low cost and high water recovery rate" of electro-mixed bed and "high efficiency of silicon removal" of anion exchange bed, which can significantly relax the requirements for silicon content in pre-reverse osmosis permeate, broaden the application scope of electro-mixed bed, and greatly extend the service life of reverse osmosis membrane. Attached Figure Description

[0030] Figure 1 This is a front view of the integrated device.

[0031] Figure 2 This is a top view of the integrated device.

[0032] Figure 3 This is a left view of the integrated device.

[0033] Figure 4 for Figure 1 Sectional view along the middle II direction.

[0034] The reference numerals in the figure are as follows: 1. Electric Mixed Bed: 101. Cover plate, 102. Upper housing, 103. First water distribution assembly, 104. Second water distribution assembly, 105. First reinforcing rib, 106. Upper pipe interface, 107. Second reinforcing rib, 108. Electric mixed bed resin layer, 109. First sealing gasket, 110. Second sealing gasket, 111. Anode, 112. Cathode, 113. Anode terminal, 114. Anode terminal through hole, 115. Anode terminal nut, 116. Anode terminal gasket, 117. Cathode terminal, 118. Cathode terminal through hole, 119. Cathode terminal nut, 120. Cathode terminal gasket; 2. Intermediate drainage device: 201, intermediate drainage interface, 202, water collection hole, 203, drainage channel, 204, clamping plate; 3. Anion bed: 301. Lower box body, 302. Third water distribution component, 303. Fourth water distribution component, 304. Lower pipe interface, 305. Base plate, 306. Third reinforcing rib, 307. Fourth reinforcing rib, 308. Anion bed resin layer, 309. Third sealing gasket, 310. Support feet; 4. First bolt group; 5. Second bolt group. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0037] like Figures 1-4 As shown, a deep treatment device for reverse osmosis permeate has an integrated structure, comprising an electro-mixed bed 1, an intermediate drainage device 2, and an anion bed 3 arranged sequentially from top to bottom. The electro-mixed bed 1, the intermediate drainage device 2, and the anion bed 3 are sequentially and sealed together as a whole.

[0038] The electro-mixed bed 1 includes a cover plate 101, an upper housing 102, a first water distribution assembly 103, a second water distribution assembly 104, an anode 111, a cathode 112, and an electro-mixed bed resin layer 108. The upper housing 102 has side walls, forming an open upper housing structure at both ends. The upper end of the upper housing 102 is sealed to the cover plate 101. An upper pipe interface 106 is located at the center of the cover plate. The first water distribution assembly 103 is located at the top of the upper housing 102, and the second water distribution assembly 104 is located at the bottom. In some embodiments, the interior of the upper housing is a cuboid structure, the cover plate is rectangular, a first reinforcing rib 105 is located at the top of the cover plate, and a second reinforcing rib 107 is located on the outer side of the side wall of the upper housing. Anode 111 and cathode 112 are respectively installed in close contact with one pair of opposing inner sidewalls of the upper chamber 102. The cavity formed by anode 111, cathode 112, first water distribution component 103, second water distribution component 104 and the other two inner sidewalls of the upper chamber is filled with cation and cathode mixed resin to form an electric mixed bed resin layer 108. The filling height of the electric mixed bed resin layer is 50~80cm.

[0039] The upper housing has two side walls corresponding to the anode and cathode, each with a through hole for the anode terminal and a through hole for the cathode terminal, respectively. The anode terminal and cathode terminal are assembled through the corresponding through holes; the anode and cathode are electrically connected to their corresponding terminals. Specifically, an anode terminal through hole 114 is provided on the side wall corresponding to the anode. This through hole extends through the side wall of the upper housing. The anode terminal 113 penetrates the anode terminal through hole 114 and is electrically connected to the anode 111 by direct electric welding. The anode terminal 113 and the anode terminal through hole 114 are sealed with insulating sealant. The anode terminal 113 is fastened to the outside of the side wall of the upper housing by an anode terminal nut 115 and an anode terminal washer 116. An anode terminal through hole 118 is provided on the side wall corresponding to the cathode 112. The through hole penetrates the side wall of the upper housing. The cathode terminal 117 penetrates the cathode terminal through hole 118 and is electrically connected to the anode 112 by direct electric welding. The cathode terminal 117 and the cathode terminal through hole 118 are sealed with insulating sealant. The cathode terminal 117 is fastened on the outside of the side wall of the upper housing by a cathode terminal nut 119 and a cathode terminal washer 120.

[0040] An intermediate drainage device 2 is clamped and fixed between the electric mixed bed 1 and the anion bed 3. The intermediate drainage device 2 has a water collection hole 202 at its center and an intermediate drainage interface 201 on one of its edge sides for discharging the anion bed regeneration waste liquid and cleaning effluent. In some embodiments, the intermediate drainage device 2 adopts a clamp-like structure, including a clamp 204, which is sealed to the electric mixed bed 1 and the anion bed 3. The water collection hole 202 axially penetrates the center of the clamp 204, and the intermediate drainage interface 201 is located on the outer edge side of the clamp. A drainage channel 203 connecting the water collection hole 202 and the intermediate drainage interface 201 is provided inside the clamp 204.

[0041] The anion exchange bed 3 includes a lower housing 301, a third water distribution component 302, a fourth water distribution component 303, and an anion exchange bed resin layer 308. The lower housing 301 has side walls and a bottom plate 305, which are integrally formed. The upper end of the lower housing is open and sealed to the clamp 204 of the intermediate drainage device 2 through the top of its side wall. A lower pipe interface 304 is provided at the center of the bottom plate. The third water distribution component 302 is located at the top of the lower housing 301, and the fourth water distribution component 303 is located at the bottom of the lower housing. Strongly alkaline anion exchange resin is filled between the third and fourth water distribution components to form the anion exchange bed resin layer 308. The filling height of the anion exchange bed resin layer 308 is 30-50 cm. In some embodiments, the interior of the lower housing is rectangular, with a third reinforcing rib 306 on the outer side of the side wall, a support foot 310 at the bottom, and a fourth reinforcing rib 307 on the outer side of the bottom plate 305. The reinforcing ribs are evenly arranged horizontally on the outer side of the sidewall, and evenly intersected on the outer side of the bottom plate and cover plate along the length and width.

[0042] In some embodiments, the second water distribution component 104 and the third water distribution component 302 are fixedly connected to the top and bottom surfaces of the clamping plate 204 of the intermediate drainage device, respectively; the first water distribution component 103 is fixedly connected to the bottom surface of the cover plate 101, and the fourth water distribution component 303 is fixedly connected to the top surface of the base plate 305.

[0043] In some embodiments, the first, second, third, and fourth water distribution components all adopt the same structure, which can be the water distribution structure found in existing electro-mixed bed systems. For example, a combined structure including a slotted plate, a support frame, and support columns can be used. The slotted plate serves both for water distribution and resin interception. The support frame and support columns of each water distribution component are supported between the slotted plate and the corresponding cover plate, clamping plate, and bottom plate. The support frame is located at the edge of the slotted plate, and 10-30 support columns are located within the area enclosed by the support frame. The support columns can be cylindrical supports with a diameter of 20-30mm and a central bolt hole. Each water distribution component is tightly fixed to its corresponding connecting surface using high-strength insulating bolts and / or acid- and alkali-resistant waterproof sealant. After the water distribution components are assembled, each slotted plate contacts the corresponding resin layer.

[0044] In some embodiments, the inner walls of the upper and lower housings, as well as the through holes of the anode and cathode terminals, are made of insulating material, or the entire housing is made of insulating material to achieve insulation isolation between the inside and outside of the housing. Insulating adhesive is used to seal the back surfaces of the anode and cathode with the inner wall of the upper housing, the anode terminals with their through holes, and the cathode terminals with their through holes. Both the upper and lower pipe interfaces use flange structures, and the sealing surfaces of the flanges and the inner sides of the pipe sections are made of insulating material.

[0045] The electric mixed bed 1, the intermediate drainage device 2, and the anion bed 3 are sequentially and sealed together. In some embodiments, the outer edges of the upper and lower housings are flange structures; the outer edges of the cover plate and the clamping plate of the intermediate drainage device are both provided with matching flange holes; a first sealing gasket 109 is sandwiched between the lower side of the cover plate and the upper end of the upper housing, and the connection is secured by a first bolt group 4; a second sealing gasket 110 is sandwiched between the lower end of the upper housing and the upper side of the clamping plate, and a third sealing gasket 309 is sandwiched between the lower side of the clamping plate and the upper end of the lower housing, and the connections are secured by a second bolt group 5.

[0046] The method for using the aforementioned integrated device to perform deep treatment via reverse osmosis is as follows: During processing, reverse osmosis permeate is fed in through the upper pipe interface and flows from top to bottom through the electro-mixed bed, the intermediate drain device, and the anion bed. The electro-mixed bed is used to remove impurities such as salts, carbon dioxide, and some silicon compounds that remain after reverse osmosis treatment, while the anion bed is used to remove silicon compounds that remain after electro-mixed bed treatment, ensuring that the conductivity and silica of the final permeate can meet the standards stably.

[0047] The electric mixed bed is periodically electro-regenerated according to a preset cycle; the anion bed is chemically regenerated by silicon content triggering, that is, at the end of the electric mixed bed treatment cycle, if the silicon content of the anion bed effluent reaches a preset threshold, both the anion bed and the electric mixed bed will be regenerated, otherwise only the electric mixed bed will be regenerated.

[0048] The operation is as follows when regenerating only the electric mixed bed: (1) Purified water is introduced from the lower pipe interface at the bottom of the anion bed, flows through the anion bed and the intermediate drainage device, and then flows into the electric mixed bed; the DC power supply is turned on to drive the electric regeneration of the resin layer of the electric mixed bed, and the regenerated concentrate is discharged from the upper pipe interface at the top and sent to the pre-reverse osmosis for recycling. (2) After regeneration, turn off the DC power supply and keep the water flow constant to clean the electro-mixed bed resin layer.

[0049] The operation is as follows when both the anion bed and the electric mixed bed are being regenerated: (1) Chemical regeneration of the anion bed: Purified water is introduced upward from the lower pipe interface at the bottom of the anion bed, and sodium hydroxide solution is added to the purified water to form a 0.1%-1.0% dilute alkali solution, which is regenerated at a flow rate of 5-10 m / h; at the same time, a small flow of reverse osmosis permeate is introduced into the top of the electric mixed bed to prevent waste alkali solution from entering the resin layer of the electric mixed bed. The mixed solution is discharged through the intermediate drain port of the intermediate drain device to adjust the pH value of the pre-reverse osmosis feed water. (2) Anion bed cleaning: Stop adding chemicals, keep the water flow constant, clean the anion bed, and discharge the water along the above path. This is also used to adjust the pH value of the pre-reverse osmosis feed water. (3) Continue cleaning the anion bed while regenerating the electro-mixed bed: continue cleaning the anion bed with purified water (at this time, the middle drain port is closed), and the anion bed cleaning water flows into the electro-mixed bed from bottom to top. At the same time, turn on the DC power supply to drive the regeneration of the electro-mixed bed resin layer. The electro-regeneration concentrate is discharged from the pipe interface at the top of the electro-mixed bed and sent to the pre-reverse osmosis for recycling. (4) Synchronous cleaning: Turn off the power, keep the water flow the same as in step (3), and clean the anion bed and the electro-mixed bed resin layer simultaneously. The cleaning effluent is also sent to the pre-reverse osmosis system for recycling.

[0050] Example 1: The reverse osmosis permeate has a conductivity of approximately 3.5 µS / cm and a silica content of approximately 300 μg / L. Figures 1-4 The integrated "electro-mixed bed-anion bed" equipment shown is used for processing. The heights of the electro-mixed bed resin layer and the anion bed resin layer are 60cm and 50cm, respectively.

[0051] Operating conditions are as follows: processing flow rate 110 m³ / h; processing flow rate 40 m³ / h. 3 / h; Electroregeneration current density 150A / m 2 Average voltage 320V; electro-regeneration and cleaning flow rate 55 m / h; electro-regeneration and cleaning flow rate 20 m³ / h. 3 / h; the processing time in each electro-mixed bed operation cycle is 220 minutes, with regeneration and cleaning lasting 18 minutes and 2 minutes respectively; the anion bed undergoes silicon content-triggered chemical regeneration, meaning that at the end of the electro-mixed bed treatment cycle, if the silicon content in the anion bed effluent reaches a preset threshold (set at 4.0 μg / L), the anion bed is regenerated before starting the electro-mixed bed regeneration. In this embodiment, the anion bed is typically regenerated every 24 hours, with a regeneration flow rate of approximately 5.6 m / h and a regeneration flow rate of 2.0 m³ / h. 3 / h, regeneration time is 20 minutes, and a single regeneration consumes 4.0L of 30% sodium hydroxide solution.

[0052] The operating results are as follows: effluent conductivity 0.06-0.07 µS / cm, silica content 1.5-5.0 μg / L; water recovery rate approximately 95%; DC power consumption approximately 0.041 kWh / m³. 3 water.

[0053] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for advanced treatment of reverse osmosis permeate, characterized in that, The treatment system employs an electro-mixed bed and an anion exchange bed connected in series, with an intermediate drain device between them. During treatment, reverse osmosis permeate flows from top to bottom through the electro-mixed bed, the intermediate drain device, and the anion exchange bed. The electro-mixed bed removes residual salts, carbon dioxide, and some silicon compounds from the reverse osmosis treatment, while the anion exchange bed removes residual silicon compounds from the electro-mixed bed treatment, ensuring that the conductivity and silica of the final permeate consistently meet the standards. The electric mixed bed is periodically electro-regenerated according to a preset cycle; the anion bed is chemically regenerated by silicon content triggering, that is, at the end of the electric mixed bed treatment cycle, if the silicon content of the anion bed effluent reaches a preset threshold, both the anion bed and the electric mixed bed will be regenerated, otherwise only the electric mixed bed will be regenerated. The operation is as follows when both the anion bed and the electric mixed bed are being regenerated: (1) Chemical regeneration of the anion bed: Purified water is introduced from the bottom of the anion bed upwards, and sodium hydroxide solution is added to form a 0.1%-1.0% dilute alkali solution, which is regenerated at a flow rate of 5-10 m / h; at the same time, a small flow of reverse osmosis permeate is introduced from the top of the electric mixed bed to prevent waste alkali solution from entering the resin layer of the electric mixed bed. The mixed solution is discharged through the intermediate drain device and used to adjust the pH value of the pre-reverse osmosis feed water. (2) Anion bed cleaning: Stop adding chemicals, keep the water flow constant, clean the anion bed, and discharge the water along the same path as in step (1). This is also used to adjust the pH value of the pre-reverse osmosis feed water. (3) Continue cleaning of the anion bed / regeneration of the electro-mixed bed: The anion bed is cleaned with purified water. The anion bed cleaning water flows into the electro-mixed bed from bottom to top. At the same time, the DC power supply is turned on to drive the regeneration of the electro-mixed bed resin layer. The electro-regeneration concentrate is discharged from the top of the electro-mixed bed and sent to the pre-reverse osmosis for recycling. (4) Synchronous cleaning: Turn off the DC power supply, keep the water flow constant, and simultaneously clean the anion bed and the electro-mixed bed resin layer. The cleaning effluent is also sent to the pre-reverse osmosis system for recycling.

2. The method for deep treatment of reverse osmosis permeate according to claim 1, characterized in that, The operation is as follows when regenerating only the electric mixed bed: (1) Purified water is introduced from the bottom of the anion bed, flows through the anion bed and the intermediate drainage device, and then flows into the electric mixed bed; the DC power supply is turned on to drive the electric regeneration of the resin layer of the electric mixed bed, and the regenerated concentrate is discharged from the top and sent to the pre-reverse osmosis for recycling. (2) After regeneration, turn off the DC power supply and keep the water flow constant to clean the electro-mixed bed resin layer.

3. A depth processing apparatus for implementing the depth processing method of claim 1 or 2, characterized in that, It adopts an integrated structure, which consists of an electro-mixed bed, an intermediate drainage device and an anion bed from top to bottom, and the three are connected by a seal to form a whole. The electro-mixed bed includes a cover plate, an upper chamber, a first water distribution assembly, a second water distribution assembly, an anode, and a cathode. The cover plate is rectangular with a first reinforcing rib at the top and an upper pipe interface at the center. The upper chamber is located below the cover plate and is sealed to it. It is open at both the top and bottom, and its lower end is sealed to the intermediate drainage device. It has a second reinforcing rib on the outside and is rectangular in shape inside. The first and second water distribution assemblies are located at the upper and lower ends of the upper chamber, respectively. The anode and cathode are respectively attached to two opposite inner sidewalls of the upper chamber. The cavity formed by the anode, cathode, the other two inner sidewalls of the upper chamber, and the first and second water distribution assemblies is filled with a mixture of anion and cathode resin to form an electro-mixed bed resin layer. The intermediate drainage device has a water collection hole at its center and an intermediate drainage interface on one of its edges for discharging waste liquid from the anion bed regeneration and cleaning water. The anion exchange bed is provided with a lower chamber, a third water distribution assembly, and a fourth water distribution assembly. The upper end of the lower chamber is open and sealed to the intermediate drainage device. The lower end is provided with a base plate with a central lower pipe interface. The interior is rectangular, and the outer side wall is provided with a third reinforcing rib and supporting feet. The lower side of the base plate is provided with a fourth reinforcing rib. The third water distribution assembly and the fourth water distribution assembly are located at the upper and lower ends of the lower chamber, respectively. The space between them is filled with a strong alkaline anion exchange resin to form an anion exchange bed resin layer.

4. The deep processing apparatus according to claim 3, characterized in that, The intermediate drainage device adopts a clamp-like structure, and the water collection hole axially passes through the center of the clamp-like structure. The interior of the clamp-like structure is provided with a drainage channel connecting the water collection hole and the intermediate drainage interface.

5. The deep processing apparatus according to claim 4, characterized in that, The upper and lower housings have flange structures on their outer edges; the cover plate and the outer edge of the intermediate drain device both have matching flange holes; a first sealing gasket is sandwiched between the lower side of the cover plate and the upper end of the upper housing, and the connection is secured by a first bolt group; a second sealing gasket is sandwiched between the lower end of the upper housing and the upper side of the intermediate drain device, and a third sealing gasket is sandwiched between the lower side of the intermediate drain device and the upper end of the lower housing, and the connections are secured by a second bolt group.

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