System for purification and resource recycling of concentrated brine

Abstract

This invention provides a concentrated brine purification and resource recovery system, belonging to the field of saline wastewater treatment technology. It includes: a bioreactor product water tank, a primary nanofiltration unit, a secondary nanofiltration unit, a secondary nanofiltration desalination tank, a high-pressure reverse osmosis feed pump, a high-pressure reverse osmosis unit, a high-pressure reverse osmosis concentrate tank, and a high-pressure reverse osmosis concentrate delivery pump, all connected sequentially in a reclaimed water workshop. The primary nanofiltration unit is also connected to the primary nanofiltration concentrate tank and the primary nanofiltration concentrate delivery pump. A total nitrogen removal unit is installed between the high-pressure reverse osmosis feed pump and the high-pressure reverse osmosis unit. The high-pressure reverse osmosis concentrate delivery pump is sequentially connected to a TOC removal unit and a sodium chloride solution collection tank. This system purifies and recovers the concentrated brine generated in existing reclaimed water systems. The treated sodium chloride solution is reused in the plant's sodium chloride electrolysis process, improving the overall wastewater treatment system's recovery rate and reducing external discharge and fresh water consumption.

Description

Technical Field

[0001] This utility model relates to the field of saline wastewater treatment technology, and in particular to a system for purifying and recycling concentrated brine. Background Technology

[0002] In current technologies, with the development and progress of coal chemical technology, a large amount of wastewater is discharged during the production process. The daily wastewater volume of a single coal chemical plant can reach tens of thousands of tons, exacerbating water pollution. This wastewater is mainly divided into saline wastewater and organic wastewater. The main sources of saline wastewater include circulating water discharge, demineralized water plant discharge, boiler discharge, and chemical cleaning discharge. High-salinity wastewater has high solubility, and the drying and crystallization of wastewater are key aspects of zero-discharge in coal chemical processes. This process places extremely high demands on treatment technology; improper treatment can lead to contamination of wastewater storage ponds and secondary environmental pollution. Currently, high-salinity wastewater is generally treated using evaporation crystallization technology. However, traditional evaporation crystallization technology for treating high-salinity wastewater suffers from high energy consumption and a significant risk of secondary pollution from crystallized salts. Secondly, due to the significant increase in productivity of coal chemical enterprises in recent years, wastewater discharge has also increased substantially, leading to a corresponding increase in the production of coal chemical crystalline salts. This increases treatment costs while reducing economic benefits. Furthermore, crystalline salts are easily soluble in water, and improper storage can easily cause secondary pollution. Additionally, high-salt wastewater such as reverse osmosis concentrate produced by existing wastewater reuse systems contains large amounts of pollutants such as COD and TOC, making it unsuitable for evaporation crystallization technology to recover sodium chloride. This saline wastewater is primarily discharged to the industrial park's wastewater treatment plant, resulting in reduced water resource circulation and persistently high fresh water consumption.

[0003] Therefore, at present, how to purify and utilize saline wastewater, especially concentrated brine, so that it can be transformed from a "treatment burden" into an "alternative water source", achieve zero discharge of coal chemical wastewater, significantly reduce water intake and sewage discharge costs, and enable concentrated brine to be utilized as a resource is particularly important and is a technical problem that still needs to be studied and overcome at this stage. Utility Model Content

[0004] This invention provides a purification and resource recycling system for concentrated brine, which solves the problems of large volume of high-salt wastewater to be treated and high pollutant content, making it unsuitable to use evaporation and crystallization to recover sodium chloride, resulting in high wastewater discharge, reduced water resource circulation, and high consumption of fresh water.

[0005] This utility model provides a concentrated brine purification and resource recycling system, comprising: a bioreactor product water tank, a primary nanofiltration unit, a secondary nanofiltration unit, a secondary nanofiltration desalination tank, a high-pressure reverse osmosis feed pump, a high-pressure reverse osmosis unit, a high-pressure reverse osmosis concentrate tank, and a high-pressure reverse osmosis concentrate delivery pump, all connected in sequence in a reclaimed water workshop; the primary nanofiltration unit is also connected to the primary nanofiltration concentrate tank and the primary nanofiltration concentrate delivery pump; the high-pressure reverse osmosis unit is also connected to a reverse osmosis product water tank; a total nitrogen removal unit is provided between the high-pressure reverse osmosis feed pump and the high-pressure reverse osmosis unit; the high-pressure reverse osmosis concentrate delivery pump is connected in sequence to a TOC removal unit and a sodium chloride solution collection tank; the sodium chloride solution in the sodium chloride solution collection tank can be sent back to the production unit.

[0006] Furthermore, the total nitrogen removal unit includes an aerated biological filter, a biological filter product tank, an autotrophic denitrification device, and a denitrification product water delivery pump connected in sequence; the autotrophic denitrification device includes two autotrophic denitrification towers connected in series.

[0007] Furthermore, the autotrophic denitrification device includes a primary denitrification inlet pump, a primary autotrophic denitrification tower, a primary autotrophic denitrification product water tank, a secondary denitrification inlet pump, a secondary autotrophic denitrification tower, and a secondary autotrophic denitrification product water tank connected in sequence.

[0008] Furthermore, the aerated biological filter is also connected to an aeration blower; a primary denitrification circulation pump is installed between the primary autotrophic denitrification product tank and the primary autotrophic denitrification tower; and a secondary denitrification circulation pump is installed between the secondary autotrophic denitrification product tank and the secondary autotrophic denitrification tower.

[0009] Furthermore, the bottom of the aerated biological filter is equipped with a pebble cushion layer, and the ceramic granule packing material is built in. The filling rate of the ceramic granule packing material is 50%. In the primary autotrophic denitrification tower, the filling rate of the autotrophic denitrification packing material is 55%; in the secondary autotrophic denitrification tower, the filling rate of the autotrophic denitrification packing material is 52%.

[0010] Furthermore, the TOC removal unit includes, in sequence, a pH adjustment tank, a decarbonization tower inlet tank, a decarbonization tower booster pump, a decarbonization tower, an alkali adjustment tank, a product water tank, an oxidation tower booster pump, an oxidation inlet water heat exchanger, a catalytic oxidation tower, a decarbonization product water tank, and a decarbonization product water delivery pump.

[0011] Furthermore, the pH adjustment tank is also connected to a hydrochloric acid metering tank, which is connected to the hydrochloric acid transfer pump in the wastewater workshop; the alkali adjustment tank is also connected to a liquid alkali metering tank, which is connected to the liquid alkali transfer pump in the wastewater workshop; and the catalytic oxidation tower is also connected to the ozone generator in the wastewater workshop.

[0012] Furthermore, the catalytic oxidation tower is also connected in sequence to a tail gas heat exchanger, a gas-liquid separator, and a tail gas destroyer.

[0013] The concentrated brine purification and resource recycling system provided by this utility model, by adding a total nitrogen removal unit and a TOC removal unit to the existing wastewater recycling system, purifies and recycles the concentrated brine (high-pressure reverse osmosis concentrate) generated in the wastewater recycling system, so that the total nitrogen in the high-pressure reverse osmosis concentrate is ≤10mg / L and the TOC is ≤10mg / L, which meets the technical indicators for sodium chloride solution recycling and can be reused in the production process (such as the sodium chloride electrolysis process in the plant itself), reducing the amount of fresh water replenishment, improving the recycling rate of the entire wastewater treatment system, reducing the amount of external discharge, realizing the conservation and recycling of water resources, and also reducing wastewater treatment costs and production costs.

[0014] This system employs an "aerated biological filter + autotrophic denitrification" technology to remove total nitrogen (mainly nitrate and nitrite) from wastewater. The effluent quality meets the requirement of total nitrogen ≤2mg / L, with a total nitrogen removal rate of over 90%. It also utilizes clean and efficient advanced catalytic oxidation technology to deeply treat the high-pressure reverse osmosis concentrate, removing TOC from the wastewater and meeting the requirement of effluent TOC ≤10mg / L. The effluent quality is stable, and the entire system has high denitrification efficiency and low sludge production. Organic matter can be oxidized into CO2, H2O, and inorganic salts, avoiding the discharge of saline wastewater and further achieving zero wastewater discharge. This significantly reduces water intake and sewage discharge costs and enables the resource utilization of concentrated brine. Attached Figure Description

[0015] 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of the structure of a concentrated brine purification and resource recycling system provided in one embodiment of this utility model; Figure 2 This is a schematic diagram of the structure of a total nitrogen removal unit provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of the structure for removing the TOC unit according to one embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 11-Bioreactor product water tank; 21-First-stage nanofiltration unit; 22-Second-stage nanofiltration unit; 23-Second-stage nanofiltration desalination tank; 24-First-stage nanofiltration concentrate tank; 25-First-stage nanofiltration concentrate delivery pump; 31-High-pressure reverse osmosis feed pump; 32-High-pressure reverse osmosis unit; 33-High-pressure reverse osmosis concentrate tank; 34-High-pressure reverse osmosis concentrate delivery pump; 35-Reverse osmosis product water tank; 41-Aerated biological filter; 42-Biological filter product water tank; 43-First-stage denitrification feed pump; 44-First-stage autotrophic denitrification tower; 45-First-stage autotrophic denitrification product water tank; 46-Second-stage denitrification feed pump; 47-Second-stage autotrophic denitrification tower; 48-Second-stage autotrophic denitrification product water tank; 49-Denitrification product water delivery pump. 51-pH Adjustment Tank, 52-Decarbonization Tower Inlet Tank, 53-Decarbonization Tower Booster Pump, 54-Decarbonization Tower, 55-Alkali Adjustment Tank, 56-Product Water Tank, 61-Oxidation Tower Booster Pump, 62-Oxidation Inlet Heat Exchanger, 63-Catalytic Oxidation Tower, 64-Decarbonization Product Water Tank, 65-Decarbonization Product Water External Pump, 71-Sodium Chloride Solution Collection Tank, 411-Aeration Blower, 441-Primary Denitrification Circulation Pump, 471-Secondary Denitrification Circulation Pump, 511-Hydrochloric Acid Metering Tank, 512-Hydrochloric Acid Transfer Pump, 551-Liquid Alkali Metering Tank, 552-Liquid Alkali Transfer Pump, 631-Ozone Generator, 632-Tail Gas Heat Exchanger, 633-Gas-Liquid Separator, 634-Tail Gas Destroyer. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are also within the protection scope of this utility model.

[0019] like Figure 1 This utility model discloses a concentrated brine purification and resource recycling system, comprising: a bioreactor product water tank 11, a primary nanofiltration unit 21, a secondary nanofiltration unit 22, a secondary nanofiltration desalination tank 23, a high-pressure reverse osmosis feed water pump 31, a high-pressure reverse osmosis unit 32, a high-pressure reverse osmosis concentrate tank 33, and a high-pressure reverse osmosis concentrate delivery pump 34, all connected sequentially in a reclaimed water workshop; the primary nanofiltration unit 21 is also connected to the primary nanofiltration concentrate tank 24 and the primary nanofiltration concentrate delivery pump 25; the high-pressure reverse osmosis unit 32 is also connected to a reverse osmosis product water tank 35; a total nitrogen removal unit is provided between the high-pressure reverse osmosis feed water pump 31 and the high-pressure reverse osmosis unit 32; the high-pressure reverse osmosis concentrate delivery pump 34 is sequentially connected to a TOC removal unit and a sodium chloride solution collection tank 71; the sodium chloride solution in the sodium chloride solution collection tank 71 can be sent back to the production unit.

[0020] In the aforementioned concentrated brine purification and resource recycling system, except for the total nitrogen removal unit, the TOC removal unit, and the sodium chloride solution collection tank 71, all other components are devices from the existing greywater recycling system in the greywater workshop. That is, this concentrated brine purification and resource recycling system purifies and reuses the concentrated brine (high-pressure reverse osmosis concentrate) generated in the greywater recycling system, improving the overall wastewater treatment system's reuse rate, reducing external discharge, achieving water conservation and recycling, and lowering wastewater treatment and production costs. By installing a total nitrogen removal unit at the nanofiltration permeate end, the total nitrogen in the permeate can be guaranteed to be ≤2mg / L. After passing through the high-pressure reverse osmosis unit 32, the total nitrogen in the high-pressure reverse osmosis concentrate is ≤10mg / L. Installing a TOC removal unit at the concentrate end of the high-pressure reverse osmosis unit 32 ensures that the TOC in the solution is ≤10mg / L, allowing the treated sodium chloride solution to meet the technical requirements for reuse and be recycled in production processes (such as the plant's own sodium chloride electrolysis process), reducing the amount of fresh water needed for replenishment.

[0021] like Figure 2 Preferably, the total nitrogen removal unit includes an aerated biological filter 41, a biological filter product tank 42, an autotrophic denitrification device, and a denitrification product water delivery pump 49 connected in sequence; the autotrophic denitrification device includes two autotrophic denitrification towers connected in series. The total nitrogen to be removed from the wastewater mainly exists in the form of nitrate nitrogen and nitrite nitrogen. The total nitrogen removal unit adopts the "aerated biological filter + autotrophic denitrification" technology to remove total nitrogen from the wastewater, and the effluent water quality meets the requirement of total nitrogen ≤2mg / L, with a total nitrogen removal rate of over 90%.

[0022] Preferably, the autotrophic denitrification device includes a primary denitrification influent pump 43, a primary autotrophic denitrification tower 44, a primary autotrophic denitrification product water tank 45, a secondary denitrification influent pump 46, a secondary autotrophic denitrification tower 47, and a secondary autotrophic denitrification product water tank 48 connected in sequence. Autotrophic denitrification technology has significant advantages such as high denitrification efficiency, low operating cost, wide application range, low sludge production, and no risk of COD exceeding standards. After the wastewater undergoes the conversion of ammonia nitrogen to nitrate nitrogen in the aerated biological filter 41, it can sequentially enter the primary autotrophic denitrification tower 44 and the secondary autotrophic denitrification tower 47, achieving a total nitrogen removal rate of over 93%.

[0023] In the specific implementation of this embodiment, the aerated biological filter 41 uses BioPower100 autotrophic nitrifying bacteria, while the primary autotrophic denitrification tower 44 and the secondary autotrophic denitrification tower 47 use BioPower116 autotrophic denitrifying bacteria. The dosage of these bacteria is determined by the production situation. This invention does not limit the specific types of autotrophic nitrifying and denitrifying bacteria; any commonly used bacteria in the art can be used, and the selection should be made by technical personnel based on the production water quality.

[0024] Preferably, the aerated biological filter 41 is also connected to an aeration blower 411; a primary denitrification circulation pump 441 is also installed between the primary autotrophic denitrification product tank 45 and the primary autotrophic denitrification tower 44; and a secondary denitrification circulation pump 471 is also installed between the secondary autotrophic denitrification product tank 48 and the secondary autotrophic denitrification tower 47.

[0025] Preferably, the bottom of the aerated biological filter 41 is equipped with a pebble cushion layer, and the inner layer is filled with ceramsite packing material. The ceramsite packing material filling rate is 50%. In the primary autotrophic denitrification tower 44, the filling rate of the autotrophic denitrification packing material is 55%; in the secondary autotrophic denitrification tower 47, the filling rate of the autotrophic denitrification packing material is 52%. Autotrophic nitrifying bacteria are attached to the ceramsite in the aerated biological filter 41. Through aeration and oxygenation, they degrade ammonia nitrogen in the water, converting ammonia nitrogen into nitrate, thereby increasing the substrate concentration for the subsequent autotrophic denitrification unit and ensuring the final effluent quality. The ammonia nitrogen removal rate can reach 90%. The autotrophic denitrification packing material is a special packing material for denitrification towers. The main material is a sulfur-iron-based composite functional material, and its water leachate does not contain any toxic or harmful substances. Technicians may also choose other packing materials commonly used in the field. This is only an example and no specific limitation is made.

[0026] like Figure 3 Preferably, the TOC removal unit includes, in sequence, a pH adjustment tank 51, a decarbonization tower inlet tank 52, a decarbonization tower booster pump 53, a decarbonization tower 54, an alkali adjustment tank 55, a product water tank 56, an oxidation tower booster pump 61, an oxidation inlet water heat exchanger 62, a catalytic oxidation tower 63, a decarbonization product water tank 64, and a decarbonization product water delivery pump 65.

[0027] The TOC removal unit employs clean and efficient advanced catalytic oxidation technology to deeply treat high-pressure reverse osmosis concentrate, removing TOC from the wastewater to meet the requirement of effluent TOC ≤10mg / L and stable effluent quality. High-pressure reverse osmosis concentrate generally has high alkalinity; by adding acid to adjust the wastewater pH, the alkalinity removal rate is high and no sludge is generated. For the removal of organic matter in the wastewater, advanced catalytic oxidation technology is used. The highly reactive hydroxyl radicals generated on the catalyst surface rapidly oxidize and decompose most recalcitrant organic pollutants, ultimately oxidizing them into CO2, H2O, and inorganic salts. Catalytic oxidation tower 63 uses a salt-resistant multi-metal composite catalyst and oxidation-resistant packing material. Technicians may also choose other commonly used packing materials and catalysts in this field; this is only an example and not a specific limitation.

[0028] Preferably, the pH adjustment tank 51 is also connected to a hydrochloric acid metering tank 511, which is connected to the hydrochloric acid transfer pump 512 of the wastewater workshop; the alkali adjustment tank 55 is also connected to a liquid alkali metering tank 551, which is connected to the liquid alkali transfer pump 552 of the wastewater workshop; and the catalytic oxidation tower 63 is also connected to the ozone generator 631 of the wastewater workshop.

[0029] Preferably, the catalytic oxidation tower 63 is further connected in sequence to a tail gas heat exchanger 632, a gas-liquid separator 633, and a tail gas destroyer 634. The ozone utilization rate of the catalytic oxidation tower 63 is over 95%, and the remaining ozone is decomposed by the tail gas destroyer 634 and converted into oxygen, which meets the emission environmental protection standards and is finally discharged into the atmosphere.

[0030] It should be noted that the aerated biological filter 41, the autotrophic denitrification tower, the decarbonization tower 54, the catalytic oxidation tower 63 and other devices are all commonly used devices in this field. Their structure, operation, backwashing and other modes are also basic common knowledge in this field, and are not described in detail here, nor are any special restrictions imposed.

[0031] It should be noted that arrows without reference numerals indicate the flow direction of gas-liquid mixtures, gas phases, or liquid phases.

[0032] In the above-mentioned concentrated brine purification and resource recycling system, the reclaimed water recycling system in the reclaimed water workshop operates normally. The production wastewater enters the first-stage nanofiltration unit 21 through the bioreactor product water tank 11. The resulting concentrated water is sent out through the first-stage nanofiltration concentrated water tank 24 and the first-stage nanofiltration concentrated water external pump 25. The resulting fresh water is sent to the second-stage nanofiltration unit 22. The resulting fresh water is sent to the second-stage nanofiltration fresh water tank 23. The concentrated water is sent back to the bioreactor product water tank 11 for recycling. The freshwater in the secondary nanofiltration freshwater tank 23 is sent to the total nitrogen removal unit via the high-pressure reverse osmosis feed pump 31, where the total nitrogen in the water is removed. The denitrified wastewater enters the high-pressure reverse osmosis unit 32, and the resulting freshwater is sent to the reverse osmosis permeate tank 35. The resulting concentrate is sent to the TOC removal unit via the high-pressure reverse osmosis concentrate external pump 34, where the TOC in the water is removed. The sodium chloride in the treated wastewater meets the reuse standard and is sent to the sodium chloride solution collection tank 71 for temporary storage. Finally, it can be sent back to the plant for use in its own sodium chloride electrolysis process.

[0033] The total nitrogen removal unit processes 13m³ of water. 3For example, with a flow rate of / h, the total nitrogen in the influent is ≤200mg / L, the ammonia nitrogen concentration in the influent is ≤5mg / L, and the fluctuation in water volume and quality does not exceed 10%. Nanofiltration desalinated water enters the aerated biological filter 41 through the high-pressure reverse osmosis influent pump 31. After aeration by the aeration blower 411 and treatment by autotrophic nitrifying bacteria, the permeate enters the permeate tank 42 of the biological filter. Then, it is sent to the first-stage autotrophic denitrification tower 44 by the first-stage denitrification influent pump 43. After treatment by the autotrophic denitrifying bacteria in the tower, the permeate enters the first-stage autotrophic denitrification permeate tank 45. Then, it is sent to the second-stage autotrophic denitrification tower 47 by the second-stage denitrification influent pump 46. After further treatment by the autotrophic denitrifying bacteria in the tower, the total nitrogen removal rate can reach more than 90%. The permeate enters the second-stage autotrophic denitrification permeate tank 48, and the effluent water quality meets the requirement of total nitrogen ≤2mg / L. The final permeate is sent to the high-pressure reverse osmosis unit 32 via the denitrification permeate external pump 49, and the total nitrogen in the resulting concentrate is ≤10mg / L. The primary autotrophic denitrification permeate tank 45 and the primary autotrophic denitrification tower 44 are connected by a primary denitrification circulation pump 441 for wastewater circulation treatment and flow regulation. Similarly, the secondary autotrophic denitrification permeate tank 48 and the secondary autotrophic denitrification tower 47 are connected by a secondary denitrification circulation pump 471 for wastewater circulation treatment and flow regulation.

[0034] The TOC removal unit processes 5m³ of water. 3 Taking a flow rate of / h as an example, the influent TOC ≤ 50 mg / L and alkalinity ≤ 1750 mg / L. High-pressure reverse osmosis concentrate from the high-pressure reverse osmosis concentrate delivery pump 34 first enters the pH adjustment tank 51. Hydrochloric acid from the hydrochloric acid transfer pump 512 is metered by the hydrochloric acid metering tank 511 and then sent to the wastewater in the pH adjustment tank 51 to lower the pH. The wastewater is then sent to the decarbonation tower inlet tank 52, where the TOC ≤ 50 mg / L and the alkalinity ≤ 175 mg / L. The wastewater is then sent to the decarbonation tower 54 via the decarbonation tower booster pump 53, where free carbon dioxide is removed. The permeate then enters the alkali adjustment tank 55. Liquid alkali from the liquid alkali transfer pump 552 is metered by the liquid alkali metering tank 551 and sent to the alkali adjustment tank 55. The wastewater, whose pH has been adjusted again, enters the product water tank 56, and then is sent to the oxidation tower booster pump 61 to the oxidation feed water heat exchanger 62. After being heated by hot water from the reclaimed water workshop, it enters the catalytic oxidation tower 63, where it is oxidized and decomposed by highly active hydroxyl radicals generated on the surface of the catalyst. At the same time, ozone from the ozone generator 631 in the reclaimed water workshop is also sent to the catalytic oxidation tower 63 to accelerate the oxidation process. The decarbonized product water is sent to the decarbonized product water tank 64. The TOC in the product water is ≤10mg / L and the alkalinity is ≤175mg / L. Finally, it is sent to the sodium chloride solution collection tank 71 by the decarbonized product water external pump 65. The CO2 and unused ozone produced by catalysis in the catalytic oxidation tower 63 are cooled by the tail gas heat exchanger 632 and then separated in the gas-liquid separator 633. After the gas is decomposed by the tail gas destroyer 634, the ozone is converted into oxygen and meets the emission environmental protection standards before being discharged into the atmosphere.

[0035] It should be noted that the detailed structure of some devices in this utility model is not described in detail, but belongs to the prior art known to those skilled in the art, and therefore will not be described again here. In addition, the parts of this device not described are the same as or can be implemented using existing technology.

[0036] It should be noted that those skilled in the art, under the guidance of this utility model, can also make some modifications to the design of the above system. For example, the equipment in the system is also equipped with level gauges, overflow / nitrogen pipelines, etc.; pumps, pressure sensors, flow meters or temperature sensors are installed on the conveying pipelines inside the system in different units or devices, and different valves, such as pressure relief valves, pressure regulating valves, safety valves, pneumatic valves, etc., are also installed to regulate and stabilize the pressure of the entire system, and the opening degree of the valves can also be adjusted to regulate the flow rate of materials in the pipeline, etc.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A system for purifying and recycling concentrated brine, characterized in that, include: The system is located in the greywater workshop and consists of, in sequence, a bioreactor product water tank, a primary nanofiltration unit, a secondary nanofiltration unit, a secondary nanofiltration desalination tank, a high-pressure reverse osmosis feed pump, a high-pressure reverse osmosis unit, a high-pressure reverse osmosis concentrate tank, and a high-pressure reverse osmosis concentrate delivery pump; the primary nanofiltration unit is also connected to a primary nanofiltration concentrate tank and a primary nanofiltration concentrate delivery pump; the high-pressure reverse osmosis unit is also connected to a reverse osmosis product water tank. A total nitrogen removal unit is provided between the high-pressure reverse osmosis feed pump and the high-pressure reverse osmosis device; the high-pressure reverse osmosis concentrate delivery pump is connected in sequence to the TOC removal unit and the sodium chloride solution collection tank; the sodium chloride solution in the sodium chloride solution collection tank can be sent back to the production unit.

2. The concentrated brine purification and resource recovery system according to claim 1, characterized in that, The total nitrogen removal unit includes an aerated biological filter, a biological filter product tank, an autotrophic denitrification device, and a denitrification product water delivery pump connected in sequence; the autotrophic denitrification device includes two autotrophic denitrification towers connected in series.

3. The concentrated brine purification and resource recovery system according to claim 2, characterized in that, The autotrophic denitrification device includes a primary denitrification inlet pump, a primary autotrophic denitrification tower, a primary autotrophic denitrification product water tank, a secondary denitrification inlet pump, a secondary autotrophic denitrification tower, and a secondary autotrophic denitrification product water tank, connected in sequence.

4. The concentrated brine purification and resource recovery system according to claim 3, characterized in that, The aerated biological filter is also connected to an aeration blower; a primary denitrification circulation pump is also installed between the primary autotrophic denitrification product tank and the primary autotrophic denitrification tower; a secondary denitrification circulation pump is also installed between the secondary autotrophic denitrification product tank and the secondary autotrophic denitrification tower.

5. The concentrated brine purification and resource recovery system according to claim 3, characterized in that, The bottom of the aerated biological filter is equipped with a pebble cushion layer and contains ceramsite packing material with a filling rate of 50%. In the primary autotrophic denitrification tower, the filling rate of the autotrophic denitrification packing material is 55%; in the secondary autotrophic denitrification tower, the filling rate of the autotrophic denitrification packing material is 52%.

6. The concentrated brine purification and resource recovery system according to any one of claims 1-5, characterized in that, The TOC removal unit includes, in sequence, a pH adjustment tank, a decarbonization tower inlet tank, a decarbonization tower booster pump, a decarbonization tower, an alkali adjustment tank, a product water tank, an oxidation tower booster pump, an oxidation inlet water heat exchanger, a catalytic oxidation tower, a decarbonization product water tank, and a decarbonization product water delivery pump.

7. The concentrated brine purification and resource recovery system according to claim 6, characterized in that, The pH adjustment tank is also connected to a hydrochloric acid metering tank, which is connected to the hydrochloric acid transfer pump in the wastewater workshop; the alkali adjustment tank is also connected to a liquid alkali metering tank, which is connected to the liquid alkali transfer pump in the wastewater workshop; the catalytic oxidation tower is also connected to the ozone generator in the wastewater workshop.

8. The concentrated brine purification and resource recovery system according to claim 6, characterized in that, The catalytic oxidation tower is also connected in sequence to a tail gas heat exchanger, a gas-liquid separator, and a tail gas destroyer.

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