Wastewater pretreatment system

Abstract

The utility model discloses a wastewater pretreatment system, which relates to the technical field of water treatment, and comprises a membrane filtration unit, a biological treatment unit and a membrane concentration unit, the membrane filtration unit is provided with a first water inlet pipe, and the membrane filtration unit is provided with a first concentrated water discharge pipe and a first clear water discharge pipe; the biological treatment unit is connected with the first clear water discharge pipe, and the biological treatment unit can utilize microorganisms to treat wastewater; the membrane concentration unit is connected with the biological treatment unit, and the membrane concentration unit is provided with a second concentrated water discharge pipe and a second clear water discharge pipe; wherein the wastewater is treated by the membrane filtration unit, the biological treatment unit and the membrane concentration unit in sequence. The wastewater pretreatment system disclosed by the utility model can provide stable high-concentration wastewater and reduce the treatment cost of the wastewater.

Description

TECHNICAL FIELD

[0001] The utility model relates to water treatment technical field, especially a kind of wastewater pretreatment system. BACKGROUND

[0002] Industrial wastewater contains a large amount of metal ions or metal salts, for example, in the process of producing ternary positive electrode material, lithium iron phosphate material, lithium cobaltate, a large amount of wastewater will be generated simultaneously. These wastewater cannot be directly discharged into the environment, and needs to be treated before discharge.

[0003] Industrial wastewater is generally treated by evaporation crystallization (MVR system) to concentrate and crystallize the salts in the wastewater, thereby realizing wastewater reduction and resource utilization. However, directly feeding wastewater into the MVR system will result in high energy consumption of the MVR system, which may exceed 100 kwh / m 3 . Another wastewater treatment method is to add chemical reagents to the wastewater to form flocs with metal ions, which are removed after coagulation and flocculation. However, using the chemical reagent addition method to treat wastewater requires adjusting the corresponding chemical reagents according to the composition and content of the wastewater, which has many detection procedures and high labor intensity. SUMMARY

[0004] The present utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the present utility model provides a wastewater pretreatment system that can provide stable high-concentration wastewater and reduce wastewater treatment cost.

[0005] The wastewater pretreatment system according to the present utility model embodiment comprises: a membrane filtration unit, the membrane filtration unit is provided with a first water inlet pipe, the membrane filtration unit has a first concentrated water discharge pipe and a first clean water discharge pipe;

[0006] a biological treatment unit, the biological treatment unit is connected with the first clean water discharge pipe, and the biological treatment unit can treat wastewater using microorganisms;

[0007] a membrane concentration unit, the membrane concentration unit is connected with the biological treatment unit, and the membrane concentration unit has a second concentrated water discharge pipe and a second clean water discharge pipe;

[0008] Wherein, the wastewater is treated in sequence by the membrane filtration unit, the biological treatment unit and the membrane concentration unit.

[0009] The wastewater pretreatment system has at least the following beneficial effects: wastewater is first subjected to membrane filtration unit, and is subjected to first concentration, and filtered concentrated water and filtered clean water are obtained after first concentration; the filtered clean water enters the biological treatment unit again, and organic matter, total phosphorus and total nitrogen in the wastewater are reduced by using microorganisms, so that the subsequent membrane concentration unit is protected, and the risk of blockage of the membrane concentration unit is reduced; the wastewater treated by the biological treatment unit enters the membrane concentration unit, and is subjected to second concentration, and concentrated clean water and concentrated concentrated water are obtained, the concentration of the wastewater can be further improved, the conductivity of the wastewater is improved, the concentrated concentrated water can be conveyed to the MVR system for evaporation crystallization, the amount of wastewater treated by the MVR system is greatly reduced, the treatment efficiency of the wastewater is improved due to the high conductivity of the wastewater, and the treatment cost of the wastewater is reduced.

[0010] According to some embodiments of the present application, the membrane filtration unit comprises a filter membrane assembly, a concentrated water tank and a clean water tank, the first water inlet pipe is connected with the filter membrane assembly, the water inlet side of the filter membrane assembly is connected with the concentrated water tank, the concentrated water tank is provided with the first concentrated water discharge pipe, the water outlet side of the filter membrane assembly is connected with the clean water tank, and the clean water tank is provided with the first clean water discharge pipe.

[0011] According to some embodiments of the present application, the filter membrane assembly is an inorganic filter membrane assembly.

[0012] According to some embodiments of the present application, the biological treatment unit comprises an anaerobic tank, an aerobic tank and an MBR reactor, the anaerobic tank is connected with the first clean water discharge pipe, the anaerobic tank is connected with the aerobic tank, the MBR reactor is arranged in the aerobic tank, and the aerobic tank is connected with the membrane concentration unit.

[0013] According to some embodiments of the present application, the membrane concentration unit comprises a reverse osmosis membrane assembly, a conveying pump and a booster pump, the reverse osmosis membrane assembly is connected with the biological treatment unit, the conveying pump is arranged between the reverse osmosis membrane assembly and the biological treatment unit, the conveying pump can pump the wastewater from the biological treatment unit to the reverse osmosis membrane assembly, the booster pump is connected with the reverse osmosis membrane assembly, and the booster pump can increase the pressure of the water inlet side of the reverse osmosis membrane assembly.

[0014] According to some embodiments of the present application, a plurality of membrane concentration units are sequentially connected according to the improvement of filtration precision.

[0015] According to some embodiments of the present invention, it further includes a dosing and sedimentation unit, which is connected to the first concentrated water discharge pipe. The dosing and sedimentation unit is provided with a third clear water discharge pipe, which is connected to the first water inlet pipe. The third clear water discharge pipe can transport the supernatant of the dosing and sedimentation unit to the membrane filtration unit.

[0016] According to some embodiments of the present invention, the dosing and sedimentation unit includes a pH adjustment tank, a coagulation adjustment tank, a flocculation adjustment tank, and a sedimentation tank. The pH adjustment tank, the coagulation adjustment tank, the flocculation adjustment tank, and the sedimentation tank are connected in sequence. The pH adjustment tank is connected to the first concentrated water discharge pipe, and the third clear water discharge pipe is connected to the upper part of the sedimentation tank.

[0017] According to some embodiments of the present invention, the dosing sedimentation unit further includes a sludge tank, which is connected to the lower part of the sedimentation tank.

[0018] According to some embodiments of the present invention, the sludge tank is also connected to a filter press.

[0019] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0021] Figure 1 This is a schematic diagram of the connection structure of the wastewater pretreatment system according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the connection structure of the membrane filtration unit according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the connection structure of the biological treatment unit according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the connection structure of the dosing precipitation unit and the filter press in an embodiment of this utility model.

[0025] Icon labels:

[0026] Membrane filtration unit 100, first concentrated water discharge pipe 110, first clean water discharge pipe 120, filtration membrane module 130, concentrated water tank 140, clean water tank 150, biological treatment unit 200, anaerobic tank 210, aerobic tank 220, membrane concentration unit 300, second concentrated water discharge pipe 310, second clean water discharge pipe 320, reverse osmosis membrane module 330, chemical dosing and sedimentation unit 400, third clean water discharge pipe 410, pH adjustment tank 420, coagulation adjustment tank 430, flocculation adjustment tank 440, sedimentation tank 450, sludge tank 460, filter press 500. Detailed Implementation

[0027] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0028] In the description of this utility model, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.

[0030] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0031] As described in the background art, furthermore, if only chemical reagents are used to treat wastewater, some metal ions in the wastewater will still be unable to precipitate and be stripped off, and an MVR system is still needed to evaporate and crystallize the wastewater to obtain metal salts.

[0032] Although directly using an MVR system to evaporate and crystallize wastewater will increase the energy consumption of the MVR system, pretreatment of the wastewater can reduce the amount of wastewater that the MVR system needs to treat, thereby reducing the energy consumption of the MVR system and the cost of wastewater treatment.

[0033] Reference Figure 1As shown, a wastewater pretreatment system according to an embodiment of the present invention includes a membrane filtration unit 100, a biological treatment unit 200, and a membrane concentration unit 300. Wastewater is treated sequentially through the membrane filtration unit 100, the biological treatment unit 200, and the membrane concentration unit 300.

[0034] The membrane filtration unit 100 is provided with a first water inlet pipe, and the membrane filtration unit 100 has a first concentrated water discharge pipe 110 and a first clean water discharge pipe 120.

[0035] Wastewater is transported to membrane filtration unit 100 through the first inlet pipe. The membrane filtration unit 100 removes insoluble solids from the wastewater. Due to the small pore size of the membrane filtration unit 100, it also initially filters out large molecules, concentrating the wastewater to obtain filtered concentrate and filtered purified water. Correspondingly, the filtered concentrate is discharged through the first concentrate discharge pipe 110, and the filtered purified water is discharged through the first purified water discharge pipe 120. The filtered concentrate can be further treated, while the filtered purified water is transported to biological treatment unit 200 through the first purified water discharge pipe 120.

[0036] The biological treatment unit 200 is connected to the first clean water discharge pipe 120, and the biological treatment unit 200 can use microorganisms to treat wastewater.

[0037] After filtration, the purified water undergoes further treatment in the biological treatment unit 200 using microorganisms. This purified water, also known as wastewater, is then processed in the biological treatment unit 200. Microorganisms carry out related biochemical reactions to reduce substances such as organic matter, total phosphorus, and total nitrogen in the wastewater. The organic matter also includes sugars. These substances have relatively large molecular structures, and if they enter the membrane concentration unit 300, they can easily cause blockage or even damage to the membrane concentration unit 300.

[0038] The membrane concentration unit 300 is connected to the biological treatment unit 200, and the membrane concentration unit 300 has a second concentrate discharge pipe 310 and a second clean water discharge pipe 320.

[0039] The wastewater treated by the biological treatment unit 200 has had its content of large molecules reduced as much as possible. The wastewater then undergoes further concentration treatment in the membrane concentration unit 300, i.e., a second concentration, yielding concentrated wastewater and purified wastewater. Compared to untreated wastewater, the volume of concentrated wastewater is significantly reduced. Controlled by the membrane concentration unit 300, the concentrated wastewater achieves a stable concentration and its conductivity is greatly improved. For example, the conductivity of untreated wastewater is 5000 μS / cm, while after treatment by the membrane filtration unit 100, biological treatment unit 200, and membrane concentration unit 300, the conductivity of the wastewater can reach 30000 μS / cm or higher. The concentrated wastewater is then transported to the MVR system for evaporation and crystallization. This significantly reduces the amount of wastewater requiring evaporation and crystallization, and the greatly improved conductivity further enhances wastewater treatment efficiency, reduces the energy consumption of the MVR system, and lowers wastewater treatment costs.

[0040] Reference Figure 2 As shown, it can be understood that the membrane filtration unit 100 includes a filter membrane assembly 130, a concentrate tank 140, and a clear water tank 150. A first inlet pipe is connected to the filter membrane assembly 130, the inlet side of the filter membrane assembly 130 is connected to the concentrate tank 140, the concentrate tank 140 is provided with a first concentrate discharge pipe 110, the outlet side of the filter membrane assembly 130 is connected to the clear water tank 150, and the clear water tank 150 is provided with a first clear water discharge pipe 120.

[0041] Wastewater is transported to the filter membrane module 130 via the first water pipe. Utilizing the pressure difference between the inlet and outlet sides of the filter membrane module 130, only water and small molecules are allowed to pass through the micropores on the membrane surface as the wastewater flows over it, while substances larger than the micropore size are retained on the inlet side. It's important to understand that the term "small molecules" refers to substances relative to the micropore size of the filter membrane module 130. Therefore, the inlet side of the filter membrane module 130 is connected to the concentrate tank 140, and the outlet side is connected to the clear water tank 150. The concentrate tank 140 is preferably made of PPH (Polyproplyene-Homo), a homopolymer of polypropylene.

[0042] In some embodiments, the total amount of untreated wastewater is 100%. After the first concentration in the membrane filtration unit 100, approximately 80% filtered clean water and approximately 20% filtered concentrate can be obtained. The filtered clean water is then sent to the biological treatment unit 200 and the membrane concentration unit 300, and finally sent to the MVR system for evaporation and crystallization, which greatly reduces the amount of wastewater that the MVR system needs to treat.

[0043] It is understood that the filter membrane assembly 130 is preferably an inorganic filter membrane assembly.

[0044] Inorganic filtration membrane modules include acid- and alkali-resistant inorganic filtration membranes and fouling-resistant inorganic filtration membranes, preferably made of silicon carbide, with a filtration accuracy of approximately 70 nm. These modules utilize high-temperature and corrosion-resistant materials such as alumina and silicon dioxide, primarily employing microporous filtration and ultrasonic technology to achieve filtration. In terms of performance characteristics, inorganic filtration membrane modules excel in corrosion resistance, thermal stability, mechanical strength, and chemical inertness, particularly in the separation of high-temperature, high-pressure, and corrosive liquids, making them ideal for the chemical industry and also suitable for wastewater treatment containing metal ions.

[0045] Reference Figure 3 As shown, it can be understood that the biological treatment unit 200 includes an anaerobic tank 210, an aerobic tank 220 and an MBR reactor. The anaerobic tank 210 is connected to the first clear water discharge pipe 120, the anaerobic tank 210 is connected to the aerobic tank 220, the MBR reactor is located in the aerobic tank 220, and the aerobic tank 220 is connected to the membrane concentration unit 300.

[0046] MBR, also known as Membrane Bio-Reactor, is a novel water treatment technology that combines membrane separation units with biological treatment units. In the biological treatment unit 200, wastewater is first transported to the anaerobic tank 210, where anaerobic microorganisms treat the substances in the wastewater. In the anaerobic tank 210, anaerobic microorganisms decompose organic matter under anaerobic conditions, converting it into low-molecular-weight organic acids, alcohol, hydrogen, and ultimately methane and carbon dioxide. The anaerobic tank does not require an oxygen supply; it utilizes the electrons within the organic matter for decomposition. The wastewater is then transported to the aerobic tank 220, where oxygen is used for biological metabolism, oxidizing the organic matter into carbon dioxide and water, thereby removing organic matter, nitrogen, and phosphorus. The microorganisms in the aerobic tank 220 primarily adhere to the MBR reactor. The MBR reactor replaces the secondary sedimentation tank at the end of traditional biological treatment technologies with membrane modules, maintaining a high concentration of active sludge in the bioreactor, increasing the organic load of biological treatment, thereby reducing the footprint of wastewater treatment facilities, and reducing the amount of residual sludge by maintaining a low sludge load.

[0047] Understandably, the membrane concentration unit 300 includes a reverse osmosis membrane module 330, a transfer pump, and a booster pump. The reverse osmosis membrane module 330 is connected to the biological treatment unit 200. The transfer pump is located between the reverse osmosis membrane module 330 and the biological treatment unit 200. The transfer pump can pump wastewater from the biological treatment unit 200 to the reverse osmosis membrane module 330. The booster pump is connected to the reverse osmosis membrane module 330 and can increase the pressure on the feed side of the reverse osmosis membrane module 330.

[0048] A transfer pump is used to pump the wastewater treated by the biological treatment unit 200 to the reverse osmosis membrane module 330, and then a booster pump increases the pressure on the feed side of the reverse osmosis membrane module 330. The concentrate after membrane concentration is on the feed side of the reverse osmosis membrane module 330, and the purified water after membrane concentration is on the effluent side of the reverse osmosis membrane module 330. It should be understood that the reverse osmosis membrane module 330 preferably uses a fouling-resistant seawater desalination reverse osmosis membrane, and reverse osmosis membranes of different pressure resistance levels can also be used depending on the conductivity of the wastewater.

[0049] Understandably, it also includes multiple membrane concentration units 300, which are connected in sequence according to the increasing filtration precision.

[0050] Multiple membrane concentration units 300 can perform multi-stage concentration of wastewater. For example, if the conductivity of the wastewater is 5000 μS / CM, after passing through one membrane concentration unit 300 (the second concentration), the conductivity can be increased to approximately 12000 μS / CM. After another membrane concentration unit 300 (the third concentration), the conductivity can be increased to over 30000 μS / CM. It is important to understand that the first concentration of the wastewater occurs at the membrane filtration unit 100.

[0051] After the wastewater is treated once in the membrane concentration unit 300, the concentration ratio can reach 60%.

[0052] Reference Figure 4 As shown, it can be understood that it also includes a dosing sedimentation unit 400, which is connected to the first concentrated water discharge pipe 110. The dosing sedimentation unit 400 is provided with a third clear water discharge pipe 410, which is connected to the first water inlet pipe. The third clear water discharge pipe 410 can transport the supernatant of the dosing sedimentation unit 400 to the membrane filtration unit 100.

[0053] Furthermore, after the wastewater undergoes its first concentration in the membrane filtration unit 100, the resulting concentrated filtrate can be transferred to the chemical dosing and sedimentation unit 400 for treatment, where metal ions in the concentrated filtrate are coagulated, flocculated, and precipitated. Of course, after treatment in the chemical dosing and sedimentation unit 400, the concentrated filtrate will also yield a supernatant, which can be further transported to the membrane filtration unit 100 for filtration. The third clean water discharge pipe 410 is preferably connected to the upper part of the chemical dosing and sedimentation unit 400 to obtain the supernatant from the chemical dosing and sedimentation unit 400 and transport it to the membrane filtration unit 100 through the first inlet pipe.

[0054] Reference Figure 4As shown, it can be understood that the dosing sedimentation unit 400 includes a pH adjustment tank 420, a coagulation adjustment tank 430, a flocculation adjustment tank 440, and a sedimentation tank 450. The pH adjustment tank 420, the coagulation adjustment tank 430, the flocculation adjustment tank 440, and the sedimentation tank 450 are connected in sequence. The pH adjustment tank 420 is connected to the first concentrated water discharge pipe 110, and the third clear water discharge pipe 410 is connected to the upper part of the sedimentation tank 450.

[0055] Furthermore, the pH adjustment tank 420 can be further subdivided into an acid adjustment tank and an alkali adjustment tank connected in sequence. The concentrated water after filtration is adjusted to the required pH value in the pH adjustment tank 420, and then coagulant is added to the coagulation adjustment tank 430 for coagulation reaction. Then it enters the flocculation adjustment tank 440 where flocculant is added for flocculation reaction, and then it is transported to the sedimentation tank 450 for static sedimentation.

[0056] Understandably, the dosing sedimentation unit 400 also includes a sludge tank 460, which is connected to the lower part of the sedimentation tank 450.

[0057] After the sludge tank 460 is installed, the sedimentation tank 450 can also be connected to the sludge tank 460 to transport the mud-water mixture at the bottom of the sedimentation tank 450 to the sludge tank 460 for further sedimentation of sludge.

[0058] Understandably, sludge tank 460 is also connected to filter press 500.

[0059] The sludge is finally transported to filter press 500 for filtration to obtain waste residue. Preferably, filter press 500 is a plate and frame filter press.

[0060] It should be understood that the supernatant from sedimentation tank 450, the supernatant from sludge tank 460, and the clear liquid obtained after filtration by filter press 500 can all be returned to membrane filtration unit 100 for further treatment.

[0061] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A wastewater pretreatment system, characterized in that, include: A membrane filtration unit (100) is provided with a first inlet pipe, and the membrane filtration unit (100) has a first concentrate discharge pipe (110) and a first clean water discharge pipe (120). A biological treatment unit (200) is connected to the first clean water discharge pipe (120), and the biological treatment unit (200) is capable of treating wastewater using microorganisms; A membrane concentration unit (300) is connected to the biological treatment unit (200), and the membrane concentration unit (300) has a second concentrate discharge pipe (310) and a second clean water discharge pipe (320). The wastewater is processed sequentially through the membrane filtration unit (100), the biological treatment unit (200), and the membrane concentration unit (300).

2. The wastewater pretreatment system according to claim 1, characterized in that, The membrane filtration unit (100) includes a filter membrane assembly (130), a concentrate tank (140), and a clear water tank (150). The first inlet pipe is connected to the filter membrane assembly (130), the inlet side of the filter membrane assembly (130) is connected to the concentrate tank (140), the concentrate tank (140) is provided with the first concentrate discharge pipe (110), the outlet side of the filter membrane assembly (130) is connected to the clear water tank (150), and the clear water tank (150) is provided with the first clear water discharge pipe (120).

3. The wastewater pretreatment system according to claim 2, characterized in that, The filter membrane assembly (130) is an inorganic filter membrane assembly.

4. The wastewater pretreatment system according to claim 1, characterized in that, The biological treatment unit (200) includes an anaerobic tank (210), an aerobic tank (220), and an MBR reactor. The anaerobic tank (210) is connected to the first clean water discharge pipe (120), the anaerobic tank (210) is connected to the aerobic tank (220), the MBR reactor is located in the aerobic tank (220), and the aerobic tank (220) is connected to the membrane concentration unit (300).

5. The wastewater pretreatment system according to claim 1, characterized in that, The membrane concentration unit (300) includes a reverse osmosis membrane module (330), a transfer pump, and a booster pump. The reverse osmosis membrane module (330) is connected to the biological treatment unit (200). The transfer pump is located between the reverse osmosis membrane module (330) and the biological treatment unit (200). The transfer pump can pump wastewater from the biological treatment unit (200) to the reverse osmosis membrane module (330). The booster pump is connected to the reverse osmosis membrane module (330) and can increase the pressure on the feed side of the reverse osmosis membrane module (330).

6. The wastewater pretreatment system according to claim 1, characterized in that, It also includes a plurality of membrane concentration units (300), which are connected in sequence according to the increasing filtration accuracy.

7. The wastewater pretreatment system according to claim 1, characterized in that, It also includes a dosing and sedimentation unit (400), which is connected to the first concentrate discharge pipe (110). The dosing and sedimentation unit (400) is provided with a third clean water discharge pipe (410), which is connected to the first inlet pipe. The third clean water discharge pipe (410) can transport the supernatant of the dosing and sedimentation unit (400) to the membrane filtration unit (100).

8. The wastewater pretreatment system according to claim 7, characterized in that, The dosing and sedimentation unit (400) includes a pH adjustment tank (420), a coagulation adjustment tank (430), a flocculation adjustment tank (440), and a sedimentation tank (450). The pH adjustment tank (420), the coagulation adjustment tank (430), the flocculation adjustment tank (440), and the sedimentation tank (450) are connected in sequence. The pH adjustment tank (420) is connected to the first concentrated water discharge pipe (110), and the third clear water discharge pipe (410) is connected to the upper part of the sedimentation tank (450).

9. The wastewater pretreatment system according to claim 8, characterized in that, The dosing and sedimentation unit (400) also includes a sludge tank (460), which is connected to the lower part of the sedimentation tank (450).

10. The wastewater pretreatment system according to claim 9, characterized in that, The sludge tank (460) is also connected to a filter press (500).

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