A wastewater resourceful treatment system

Abstract

A wastewater resource treatment system, a first coagulation and sedimentation device carries out turbidity removal and hardness reduction treatment on homogeneous and equal amount of raw water; an ion concentration device extracts and concentrates calcium ions and magnesium ions in filtered raw water; a reverse osmosis membrane concentration assembly carries out reverse osmosis membrane concentration on raw water from which calcium ions and magnesium ions are removed; concentrated water directly enters a nanofiltration salt separation assembly without pretreatment to separate divalent salt and monovalent salt; the concentrated water end of the nanofiltration salt separation assembly is connected with a calcium sulfate crystallizer through a conveying pipeline, a calcium fluoride crystallizer is used for crystallizing calcium fluoride by using fluorine ions at the water production end of the nanofiltration salt separation assembly and introduced calcium ions, and the calcium sulfate crystallizer is used for crystallizing calcium sulfate by using sulfate ions at the concentrated water end of the nanofiltration salt separation assembly and introduced calcium ions; and a second coagulation and sedimentation device and a third coagulation and sedimentation device remove unreacted calcium ions and magnesium ions in the crystallizer. The application solves the problems of instability and high cost in high multiple concentration operation of a membrane system in a water treatment process.

Description

TECHNICAL FIELD

[0001] The present application relates to a wastewater resource treatment system, belonging to the technical field of wastewater treatment. BACKGROUND

[0002] At present, in the water treatment process, membrane concentration is an indispensable process section, and various ions are dissolved in the raw water entering the system, such as Na + , HCO3 - , SO4 2- , Cl - , F - , Ca 2+ , Mg 2+ , etc. When the reverse osmosis equipment is running, the ion concentration on the concentrated water side increases by several times, and when it reaches supersaturation, Ca 2+ , Mg 2+ ions will react with CO3 - , SO4 2- , F - ions to crystallize and precipitate CaCO3, CaSO4, CaF2, MgCO3 and other insoluble substances on the surface of the membrane element, and the concentrated SiO3 2- will react with metal cations (Ca 2+ , Mg 2+ , etc.) in water to generate silicate compounds. These problems cause the system to be prone to fouling and blockage during operation, resulting in a decrease in membrane water production and water quality, and energy waste, so it must be treated to eliminate the tendency of scaling and ensure stable operation of the membrane system.

[0003] In the prior art, coagulation sedimentation, chemical softening, ion exchange and other schemes are often used in water treatment to reduce the content of easy-scaling substances in water. However, the above methods have certain disadvantages, coagulation sedimentation can only reduce colloids, suspended solids and other pollutants, and cannot remove dissolved ions in depth; in chemical softening, the dosage of chemicals is large, the process is not easy to control, the amount of softening sludge is large, the removal efficiency of F - is low, and a large amount of ions are introduced to increase the salt content in water; the ion exchange scheme has large regeneration wastewater volume, large ion exchange resin consumption and high cost. SUMMARY

[0004] The present application provides a wastewater resource treatment system to solve the problems of instability and high cost of membrane system high-concentration operation in the water treatment process.

[0005] The technical scheme for solving the above technical problems is as follows: a wastewater resource treatment system, comprising a first coagulation and sedimentation device, a filtering device, an ion concentration device, a reverse osmosis membrane concentration assembly, a nanofiltration salt separation assembly, a calcium fluoride crystallizer, a calcium sulfate crystallizer, an ion concentration liquid pool, a second coagulation and sedimentation device, and a third coagulation and sedimentation device;

[0006] The first coagulation and sedimentation device is connected to the filtering device through a conveying pipeline, and is used for turbidity removal and hardness reduction treatment of the homogeneous and equal-amount raw water; the filtering device is used for filtering the raw water after the turbidity removal and hardness reduction treatment.

[0007] The filtering device is connected to the ion concentration device through a conveying pipeline, and the ion concentration device is used for extracting and concentrating calcium ions and magnesium ions in the filtered raw water.

[0008] The ion concentration device is connected to the reverse osmosis membrane concentration assembly through a conveying pipeline, and the reverse osmosis membrane concentration assembly is used for reverse osmosis membrane concentration of the raw water from which the calcium ions and the magnesium ions are removed.

[0009] The reverse osmosis membrane concentration assembly is connected to the nanofiltration salt separation assembly through a conveying pipeline, and the concentrated water of the reverse osmosis membrane concentration assembly directly enters the nanofiltration salt separation assembly without pretreatment to separate divalent salt and monovalent salt.

[0010] The water outlet of the nanofiltration salt separation assembly is connected to the calcium fluoride crystallizer through a conveying pipeline, the concentrated water outlet of the nanofiltration salt separation assembly is connected to the calcium sulfate crystallizer through a conveying pipeline, the inlet of the ion concentration liquid pool is connected to the ion concentration device through a conveying pipeline, and the outlet of the ion concentration liquid pool is connected to the calcium fluoride crystallizer and the calcium sulfate crystallizer through conveying pipelines respectively, the calcium fluoride crystallizer is used for crystallizing calcium fluoride from the fluorine ions at the water outlet of the nanofiltration salt separation assembly and the introduced calcium ions, and the calcium sulfate crystallizer is used for crystallizing calcium sulfate from the sulfate ions at the concentrated water outlet of the nanofiltration salt separation assembly and the introduced calcium ions.

[0011] The calcium fluoride crystallizer is connected to the second coagulation and sedimentation device through a conveying pipeline, and the second coagulation and sedimentation device is used for removing the calcium ions and the magnesium ions that are not completely reacted in the calcium fluoride crystallizer.

[0012] The calcium sulfate crystallizer is connected to the third coagulation and sedimentation device through a conveying pipeline, and the third coagulation and sedimentation device is used for removing the calcium ions and the magnesium ions that are not completely reacted in the calcium sulfate crystallizer.

[0013] As the preferred solution of the wastewater resource treatment system, it further comprises a sodium chloride concentrated solution pool connected to the second coagulation and sedimentation device through a conveying pipeline, which is used to receive the sodium chloride solution obtained after removing the unreacted calcium ions and magnesium ions.

[0014] As the preferred solution of the wastewater resource treatment system, it further comprises a bipolar membrane electrodialysis device connected to the sodium chloride concentrated solution pool through a conveying pipeline, which is connected to the ion concentration device through a conveying pipeline; the bipolar membrane electrodialysis device is used to perform bipolar membrane electrodialysis treatment on the sodium chloride solution.

[0015] As the preferred solution of the wastewater resource treatment system, it further comprises a sodium sulfate concentrated solution pool connected to the third coagulation and sedimentation device through a conveying pipeline, which is used to receive the sodium sulfate solution obtained after removing the unreacted calcium ions and magnesium ions.

[0016] As the preferred solution of the wastewater resource treatment system, it further comprises a water production pool connected to the water production end of the reverse osmosis membrane concentration assembly through a conveying pipeline, which is used to receive the water produced by the water production end of the reverse osmosis membrane concentration assembly.

[0017] As the preferred solution of the wastewater resource treatment system, the first coagulation and sedimentation device adopts at least one of a high-density sedimentation tank, a heavy medium speed sedimentation device, a mechanical accelerated clarifier, and a high-efficiency cyclone.

[0018] The second coagulation and sedimentation device and the third coagulation and sedimentation device adopt at least one of a mechanical accelerated clarifier, a high-density sedimentation tank, an electrolytic flocculation machine, and an air flotation machine.

[0019] As the preferred solution of the wastewater resource treatment system, the ion concentration device adopts an ion exchange device or a selective electrodialysis device; the filtration device adopts at least one of a granular filter material filter tank, a gravity filter tank, and a pressure filter.

[0020] As the preferred solution of the wastewater resource treatment system, after the raw water is homogenized and uniformly distributed in the conditioning tank, it is subjected to preliminary turbidity removal and hardness reduction treatment by the first coagulation and sedimentation device, and the total hardness of the effluent of the first coagulation and sedimentation device is less than 200 mg / L in terms of calcium carbonate.

[0021] As the preferred solution of the wastewater resource treatment system, the nanofiltration concentrated water of the nanofiltration salt separation assembly is introduced into the calcium sulfate crystallization, the nanofiltration water produced by the nanofiltration salt separation assembly is introduced into the calcium fluoride crystallizer, and the concentrated Ca 2+ , Mg 2+The ions are mixed with the concentrated water and the produced water of the nanofiltration respectively, and the mixing ratio is adjusted so that only CaSO4 and CaF2 crystals are precipitated.

[0022] As a preferred solution of the wastewater resource treatment system, the effluent of the calcium fluoride crystallizer and the calcium sulfate crystallizer is treated by the second coagulation sedimentation device and the third coagulation sedimentation device to remove the incompletely reacted Ca 2 +、Mg 2+ , the front-end enriched Mg 2+ serves as a magnesium agent to remove silicon in water, so that the cations in water are mainly Na + , to obtain a sodium sulfate solution and a sodium chloride solution with a specified purity.

[0023] The application is provided with a first coagulation and sedimentation device, a filtering device, an ion concentration device, a reverse osmosis membrane concentration assembly, a nanofiltration salt separation assembly, a calcium fluoride crystallizer, a calcium sulfate crystallizer, an ion concentration liquid pool, a second coagulation and sedimentation device and a third coagulation and sedimentation device; the first coagulation and sedimentation device is connected with the filtering device through a conveying pipeline, and is used for turbidity removal and hardness reduction treatment of the homogeneous and equal-amount raw water; the filtering device is used for filtering the raw water after the turbidity removal and hardness reduction treatment; the filtering device is connected with the ion concentration device through a conveying pipeline, and the ion concentration device is used for extracting and concentrating calcium ions and magnesium ions in the filtered raw water; the ion concentration device is connected with the reverse osmosis membrane concentration assembly through a conveying pipeline, and the reverse osmosis membrane concentration assembly is used for reverse osmosis membrane concentration of the raw water after the calcium ions and magnesium ions are removed; the reverse osmosis membrane concentration assembly is connected with the nanofiltration salt separation assembly through a conveying pipeline, and the concentrated water of the reverse osmosis membrane concentration assembly directly enters the nanofiltration salt separation assembly without pretreatment to separate divalent salt and monovalent salt; the water outlet of the nanofiltration salt separation assembly is connected with the calcium fluoride crystallizer through a conveying pipeline, the concentrated water end of the nanofiltration salt separation assembly is connected with the calcium sulfate crystallizer through a conveying pipeline, the inlet end of the ion concentration liquid pool is connected with the ion concentration device through a conveying pipeline, and the outlet end of the ion concentration liquid pool is connected with the calcium fluoride crystallizer and the calcium sulfate crystallizer through conveying pipelines respectively, the calcium fluoride crystallizer is used for crystallizing calcium fluoride by using the fluorine ions at the water outlet of the nanofiltration salt separation assembly and the introduced calcium ions, and the calcium sulfate crystallizer is used for crystallizing calcium sulfate by using the sulfate ions at the concentrated water end of the nanofiltration salt separation assembly and the introduced calcium ions; the calcium fluoride crystallizer is connected with the second coagulation and sedimentation device through a conveying pipeline, and the second coagulation and sedimentation device is used for removing the calcium ions and magnesium ions that are not completely reacted in the calcium fluoride crystallizer; the calcium sulfate crystallizer is connected with the third coagulation and sedimentation device through a conveying pipeline, and the third coagulation and sedimentation device is used for removing the calcium ions and magnesium ions that are not completely reacted in the calcium sulfate crystallizer. In the application, the raw water is softened by the ion concentration device, the membrane concentration end point is not controlled by hardness, the hardness removal after the first membrane concentration can be omitted, the equipment investment is reduced, there is no problem of calcium scale pollution in the concentration process of the softened water, the stability of the equipment is improved, the system power consumption is reduced due to the fact that the softening and filtering devices are not needed to be additionally arranged, the addition of the pH adjusting reagent in the softening process is reduced, the operation cost is reduced, the silicon and fluorine in the concentrated water of the reverse osmosis membrane concentration assembly can be removed by using the concentrated liquid of the ion concentration device, the use of magnesium agent and defluorination agent is reduced or avoided, the calcium ions and the sulfate after the concentration react to generate gypsum products, the hardness is further reduced, the use of softening reagent is reduced, and the operation cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the embodiments or the technical solutions of the present application, the following will briefly introduce the drawings required by the embodiments or the prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained from the provided drawings without creative labor.

[0025] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the conditions that the present application can be implemented, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that the present application can produce, should still fall within the scope of the technical content disclosed by the present application.

[0026] Figure 1 The schematic diagram of the wastewater resource treatment system provided in the embodiments of the present application is shown.

[0027] In the figure, 1 is a first coagulation and sedimentation device, 2 is a filtration device, 3 is an ion concentration device, 4 is a reverse osmosis membrane concentration assembly, 5 is a nanofiltration salt separation assembly, 6 is a calcium fluoride crystallizer, 7 is a calcium sulfate crystallizer, 8 is an ion concentration liquid pool, 9 is a second coagulation and sedimentation device, 10 is a third coagulation and sedimentation device, 11 is a sodium chloride concentrated liquid pool, 12 is a bipolar membrane electrodialysis device, 13 is a sodium sulfate concentrated liquid pool, and 14 is a water production pool. Embodiment

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below. In the following description, a lot of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0029] 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 in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] Reference Figure 1The embodiment of the present application provides a wastewater resource treatment system, which comprises a first coagulation and sedimentation device 1, a filtering device 2, an ion concentration device 3, a reverse osmosis membrane concentration assembly 4, a nanofiltration salt separation assembly 5, a calcium fluoride crystallizer 6, a calcium sulfate crystallizer 7, an ion concentration liquid pool 8, a second coagulation and sedimentation device 9 and a third coagulation and sedimentation device 10.

[0031] The first coagulation and sedimentation device 1 is connected with the filtering device 2 through a conveying pipeline, and is used for carrying out turbidity removal and hardness reduction treatment on the homogeneous and equal-amount raw water; and the filtering device 2 is used for filtering the raw water after the turbidity removal and hardness reduction treatment.

[0032] The filtering device 2 is connected with the ion concentration device 3 through a conveying pipeline, and the ion concentration device 3 is used for extracting and concentrating calcium ions and magnesium ions in the filtered raw water.

[0033] The ion concentration device 3 is connected with the reverse osmosis membrane concentration assembly 4 through a conveying pipeline, and the reverse osmosis membrane concentration assembly 4 is used for carrying out reverse osmosis membrane concentration on the raw water from which the calcium ions and the magnesium ions are removed.

[0034] The reverse osmosis membrane concentration assembly 4 is connected with the nanofiltration salt separation assembly 5 through a conveying pipeline, and the concentrated water of the reverse osmosis membrane concentration assembly 4 directly enters the nanofiltration salt separation assembly 5 without pretreatment, so as to separate divalent salt and monovalent salt.

[0035] The water production end of the nanofiltration salt separation assembly 5 is connected with the calcium fluoride crystallizer 6 through a conveying pipeline, the concentrated water end of the nanofiltration salt separation assembly 5 is connected with the calcium sulfate crystallizer 7 through a conveying pipeline, the inlet end of the ion concentration liquid pool 8 is connected with the ion concentration device 3 through a conveying pipeline, the outlet end of the ion concentration liquid pool 8 is connected with the calcium fluoride crystallizer 6 and the calcium sulfate crystallizer 7 through conveying pipelines respectively, the calcium fluoride crystallizer 6 is used for crystallizing calcium fluoride by using fluorine ions at the water production end of the nanofiltration salt separation assembly 5 and introduced calcium ions, and the calcium sulfate crystallizer 7 is used for crystallizing calcium sulfate by using sulfate ions at the concentrated water end of the nanofiltration salt separation assembly 5 and introduced calcium ions.

[0036] The calcium fluoride crystallizer 6 is connected with the second coagulation and sedimentation device 9 through a conveying pipeline, and the second coagulation and sedimentation device 9 is used for removing calcium ions and magnesium ions which are not completely reacted in the calcium fluoride crystallizer 6.

[0037] The calcium sulfate crystallizer 7 is connected with the third coagulation and sedimentation device 10 through a conveying pipeline, and the third coagulation and sedimentation device 10 is used for removing calcium ions and magnesium ions which are not completely reacted in the calcium sulfate crystallizer 7.

[0038] In the embodiment, the sodium chloride concentrated solution pool 11 is connected to the second coagulation and sedimentation device 9 through a conveying pipeline, and the sodium chloride concentrated solution pool 11 is used to receive the sodium chloride solution obtained after the calcium ions and magnesium ions that are not completely reacted are removed. The bipolar membrane electrodialysis device 12 is connected to the sodium chloride concentrated solution pool 11 through a conveying pipeline, and the bipolar membrane electrodialysis device 12 is connected to the ion concentration device 3 through a conveying pipeline; the bipolar membrane electrodialysis device 12 is used to perform bipolar membrane electrodialysis treatment on the sodium chloride solution. The sodium sulfate concentrated solution pool 13 is connected to the third coagulation and sedimentation device 10 through a conveying pipeline, and the sodium sulfate concentrated solution pool 13 is used to receive the sodium sulfate solution obtained after the calcium ions and magnesium ions that are not completely reacted are removed. The water production pool 14 is connected to the water production end of the reverse osmosis membrane concentration assembly 4 through a conveying pipeline, and the water production pool 14 is used to receive the water produced by the water production end of the reverse osmosis membrane concentration assembly 4.

[0039] In the embodiment, after the raw water is homogenized and uniformly distributed in the conditioning pool, the raw water is subjected to preliminary turbidity removal and hardness reduction treatment by the first coagulation and sedimentation device 1, so that the total hardness of the effluent is less than 200 mg / L (calculated by taking calcium carbonate as the standard). The first coagulation and sedimentation device 1 adopts one or more of a high-density sedimentation tank, a heavy medium speed sedimentation device, a mechanical acceleration clarifier, and a high-efficiency cyclone.

[0040] The effluent after the preliminary turbidity removal and hardness reduction treatment of the first coagulation and sedimentation device 1 is filtered by the filtering unit, and the filtering device 2 adopts one or more of a granular filter material filter tank, a gravity filter tank, and a pressure filter.

[0041] The effluent after the filtering of the filtering device 2 enters the ion concentration device 3 (including one or more of ion exchange and selective electrodialysis) to collect and concentrate Ca 2+ and Mg 2+ ions. The concentrated Ca 2+ and Mg 2+ ions can be stored and reacted with the concentrated water after single-stage or multi-stage concentration of the reverse osmosis membrane concentration assembly 4.

[0042] The water produced by the ion concentration device 3 enters the reverse osmosis membrane concentration assembly 4 for high-concentration concentration. Since the hardness of the water is very low, the final concentration ratio is not affected by the tendency of easy scaling substances to scale, and no hardness reduction device needs to be added between multi-stage membrane concentration.

[0043] In the embodiment, the concentrated water of the reverse osmosis membrane concentration assembly 4 is separated into divalent salts (such as SO4 2- ) and monovalent salts (such as Cl - , F - ) by the nanofiltration salt separation assembly 5. The nanofiltration concentrated water and the produced water are introduced into the calcium sulfate crystallizer 7 and the calcium fluoride crystallizer 6, respectively. At this time, the Ca2+ Mg 2+ ions are mixed with the two water streams respectively, high concentration of Ca 2+ reacts with SO4 2- , F - respectively, and the mixing ratio is adjusted to ensure that only CaSO4 and CaF2 crystals are precipitated, and the obtained precipitate is dehydrated to obtain high-quality CaSO4 and CaF2 products.

[0044] The water from the calcium fluoride crystallizer 6 and the calcium sulfate crystallizer 7 is removed by the second coagulation and precipitation device 9 and the third coagulation and precipitation device 10 to remove the unreacted Ca 2+ , Mg 2+ , and the enriched Mg 2+ at the front end can be used as a magnesium agent to remove silicon in water, at which time the cations in the water are mainly Na + . Finally, a sodium sulfate solution with high purity and a sodium chloride solution can be obtained. The first coagulation and precipitation device 1 uses one or more of a high-density sedimentation tank, a heavy medium speed sedimentation device, a mechanical acceleration clarifier, and a high-efficiency cyclone; the second coagulation and precipitation device 9 and the third coagulation and precipitation device 10 use one or more of a mechanical acceleration clarifier, a high-density sedimentation tank, an electrolytic flocculation machine, and an air flotation machine. The sodium sulfate solution is introduced into a sodium sulfate concentrated solution tank 13, and the sodium chloride solution is introduced into a sodium chloride concentrated solution tank 11, and the sodium sulfate solution and the sodium chloride solution can be further evaporated and concentrated to obtain pure water and salt.

[0045] In this embodiment, if the ion concentration device 3 uses a sodium ion exchanger, the obtained sodium chloride solution can be used to regenerate after being matched with the produced water, so that the concentration of sodium chloride is between 3% and 8%, and good regeneration effect can be achieved in the ion exchange regeneration process. If a weak acid or strong acid cation bed is used, a bipolar membrane electrodialysis device 12 can be added after nanofiltration to obtain a 3%-8% hydrochloric acid and sodium hydroxide solution to regenerate the ion exchange.

[0046] In summary, the application is provided with the first coagulation sedimentation equipment 1, the filtering equipment 2, the ion concentration equipment 3, the reverse osmosis membrane concentration assembly 4, the nanofiltration salt separation assembly 5, the calcium fluoride crystallizer 6, the calcium sulfate crystallizer 7, the ion concentration liquid pool 8, the second coagulation sedimentation equipment 9 and the third coagulation sedimentation equipment 10; the first coagulation sedimentation equipment 1 is connected with the filtering equipment 2 through the conveying pipeline, and is used for carrying out turbidity removal and hardness reduction treatment on the homogeneous and equal amount raw water; the filtering equipment 2 is used for filtering the raw water after the turbidity removal and hardness reduction treatment; the filtering equipment 2 is connected with the ion concentration equipment 3 through the conveying pipeline, and the ion concentration equipment 3 is used for extracting and concentrating the calcium ions and magnesium ions in the filtered raw water; the ion concentration equipment 3 is connected with the reverse osmosis membrane concentration assembly 4 through the conveying pipeline, and the reverse osmosis membrane concentration assembly 4 is used for carrying out reverse osmosis membrane concentration on the raw water from which the calcium ions and magnesium ions are removed; the reverse osmosis membrane concentration assembly 4 is connected with the nanofiltration salt separation assembly 5 through the conveying pipeline, and the concentrated water of the reverse osmosis membrane concentration assembly 4 directly enters the nanofiltration salt separation assembly 5 without pretreatment to separate the divalent salt and monovalent salt; the water production end of the nanofiltration salt separation assembly 5 is connected with the calcium fluoride crystallizer 6 through the conveying pipeline, the concentrated water end of the nanofiltration salt separation assembly 5 is connected with the calcium sulfate crystallizer 7 through the conveying pipeline, the inlet end of the ion concentration liquid pool 8 is connected with the ion concentration equipment 3 through the conveying pipeline, and the outlet end of the ion concentration liquid pool 8 is connected with the calcium fluoride crystallizer 6 and the calcium sulfate crystallizer 7 through the conveying pipeline respectively, the calcium fluoride crystallizer 6 is used for crystallizing the fluorine ions at the water production end of the nanofiltration salt separation assembly 5 and the introduced calcium ions into calcium fluoride, and the calcium sulfate crystallizer 7 is used for crystallizing the sulfate ions at the concentrated water end of the nanofiltration salt separation assembly 5 and the introduced calcium ions into calcium sulfate; the calcium fluoride crystallizer 6 is connected with the second coagulation sedimentation equipment 9 through the conveying pipeline, and the second coagulation sedimentation equipment 9 is used for removing the calcium ions and magnesium ions that are not completely reacted in the calcium fluoride crystallizer 6; the calcium sulfate crystallizer 7 is connected with the third coagulation sedimentation equipment 10 through the conveying pipeline, and the third coagulation sedimentation equipment 10 is used for removing the calcium ions and magnesium ions that are not completely reacted in the calcium sulfate crystallizer 7. In the application, the raw water is softened by the ion concentration equipment 3, the membrane concentration end point is not controlled by hardness, the hardness removal after the first membrane concentration can be omitted, the equipment investment is reduced, there is no problem of calcium scale pollution in the concentration process of the softened water, the stability of the equipment is improved, the system power consumption is reduced due to the fact that the subsequent softening and filtering devices are not needed, the addition of the pH adjusting reagent in the softening process is reduced, the operation cost is reduced, the concentrated liquid of the ion concentration equipment 3 can remove the silicon and fluorine in the concentrated water of the reverse osmosis membrane concentration assembly 4, the use of the magnesium agent and the defluorination agent is reduced or avoided, the calcium ions and the sulfate after the concentration react to generate gypsum products, the hardness is further reduced, the use of the softening reagent is reduced, and the operation cost is reduced.

[0047] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as there is no conflict, any combination of the technical features should be considered within the scope of the present disclosure.

[0048] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application patent should be subject to the appended claims.

Claims

1. A wastewater resource recovery treatment system, characterized by, The first coagulation sedimentation device, a filtering device, an ion concentration device, a reverse osmosis membrane concentration assembly, a nanofiltration salt separation assembly, a calcium fluoride crystallizer, a calcium sulfate crystallizer, an ion concentration liquid pool, a second coagulation sedimentation device and a third coagulation sedimentation device are included. The first coagulation sedimentation device is connected to the filtering device through a conveying pipeline; the filtering device is connected to the ion concentration device through a conveying pipeline; the ion concentration device is connected to the reverse osmosis membrane concentration assembly through a conveying pipeline; the reverse osmosis membrane concentration assembly is connected to the nanofiltration salt separation assembly through a conveying pipeline; the water production end of the nanofiltration salt separation assembly is connected to the calcium fluoride crystallizer through a conveying pipeline, and the concentrated water end of the nanofiltration salt separation assembly is connected to the calcium sulfate crystallizer through a conveying pipeline; the inlet end of the ion concentration liquid pool is connected to the ion concentration device through a conveying pipeline, and the outlet end of the ion concentration liquid pool is connected to the calcium fluoride crystallizer and the calcium sulfate crystallizer through conveying pipelines respectively; the calcium fluoride crystallizer is connected to the second coagulation sedimentation device through a conveying pipeline; and the calcium sulfate crystallizer is connected to the third coagulation sedimentation device through a conveying pipeline. A sodium chloride concentrated liquid pool is further included, which is connected to the second coagulation sedimentation device through a conveying pipeline; a bipolar membrane electrodialysis device is further included, which is connected to the sodium chloride concentrated liquid pool through a conveying pipeline, and is connected to the ion concentration device through a conveying pipeline; a sodium sulfate concentrated liquid pool is further included, which is connected to the third coagulation sedimentation device through a conveying pipeline; and a water production pool is further included, which is connected to the water production end of the reverse osmosis membrane concentration assembly through a conveying pipeline, and receives water produced by the water production end of the reverse osmosis membrane concentration assembly. After being homogenized and equally distributed in the conditioning pool, raw water is subjected to preliminary turbidity removal and hardness reduction treatment by the first coagulation sedimentation device, and the total hardness of the effluent of the first coagulation sedimentation device is less than 200 mg / L in terms of calcium carbonate; Ca 2+ , Mg 2+ ions are mixed with nanofiltration concentrated water and nanofiltration produced water respectively, and the mixing ratio is adjusted so that only CaSO4 and CaF2 crystals are precipitated; The effluent of the calcium fluoride crystallizer and the calcium sulfate crystallizer is passed through the second coagulation sedimentation device and the third coagulation sedimentation device to remove incompletely reacted Ca 2+ , Mg 2+ , and Mg 2+ enriched at the front end, which functions as a magnesium agent to remove silicon in water, so that the cations in water are mainly Na + , to obtain a sodium sulfate solution and a sodium chloride solution of a specified purity.

2. The wastewater resource recovery treatment system according to claim 1, wherein, The first coagulation sedimentation device adopts at least one of a high-density sedimentation tank, a heavy medium speed sedimentation device and a mechanical accelerated clarifier. The second coagulation sedimentation device and the third coagulation sedimentation device adopt at least one of a mechanical accelerated clarifier and a high-density sedimentation tank.

3. The wastewater resource recovery treatment system of claim 1, wherein The ion concentration device adopts an ion exchange device or a selective electrodialysis device; and the filtering device adopts a granular filter material filter tank.

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