Novel dynamic reverse osmosis and nanofiltration ultra-high concentration system and method

Abstract

The present invention provides a novel dynamic reverse osmosis and nanofiltration ultra-high concentration system and method thereof. The novel dynamic reverse osmosis and nanofiltration ultra-high concentration system comprises a first pump, a reverse osmosis system, a first three-way valve, a second three-way valve, a third three-way valve, a piston assembly, a nanofiltration system, a first circulation pump, and a second circulation pump. The above structures are combined to form multiple circulation loops, thereby increasing the brine concentration to above 250 g / L under operating pressure conditions not exceeding 70 bar. At the same time, the above data is monitored by an electrical and automatic control system, optimizing feedback information such as operating pressure, flushing flow rate, and flushing time, and making real-time adjustments, thereby significantly reducing the energy consumption and cost of high-salinity wastewater treatment and alleviating membrane fouling. The system has important application prospects.

Description

Technical Field

[0001] The present disclosure relates to the field of wastewater treatment, and in particular to a novel dynamic reverse osmosis and nanofiltration ultrahigh concentration system and a wastewater treatment method. Background Art

[0002] The development of sewage treatment technology shows a trend of green, intelligent and energy-saving. In 2022, the national industrial and urban domestic wastewater discharge problem was 43.95 billion cubic meters, of which industrial wastewater discharge was 20.72 billion cubic meters. With the continuous improvement of domestic environmental protection requirements and the improvement of corporate emission standards, more and more companies have begun to move from emission reduction to emission limitation and then to zero emission. The high-salt wastewater zero-discharge process is mainly divided into pretreatment, membrane deep treatment and evaporation crystallization. The main difficulty in the industry at present is that the evaporation crystallization process has extremely high energy consumption, which makes it very expensive to achieve complete zero sewage discharge. Therefore, it is necessary to significantly improve the concentration rate of membrane deep treatment through process improvement and upgrading, thereby reducing the later evaporation cost. Summary of the Invention

[0003] To solve the problem of low wastewater concentration rate, the present disclosure provides a novel dynamic reverse osmosis and nanofiltration ultra-high concentration system and method thereof, so as to increase the concentration of brine under low operating pressure.

[0004] In the first aspect, the present disclosure provides a novel dynamic reverse osmosis and nanofiltration ultra-high concentration system, comprising a first pump, a reverse osmosis system, a first three-way valve, a second three-way valve, a third three-way valve, a piston assembly, a nanofiltration system, a first circulation pump and a second circulation pump, wherein the output port of the first pump is connected to the reverse osmosis system, the first output port of the reverse osmosis system is connected to the outside, the second output port of the reverse osmosis system is connected to the first opening of the first three-way valve, the second opening of the first three-way valve is connected to the first piston assembly opening of the piston assembly, the third opening of the first three-way valve is connected to the second piston assembly opening of the piston assembly, the third piston assembly opening of the piston assembly is connected to the fourth opening of the second three-way valve, the fifth opening of the second three-way valve is connected to the second nanofiltration opening of the nanofiltration system, and the sixth opening of the second three-way valve is connected to the inlet of the second circulation pump. The outlet of the first circulation pump is connected to the first piston assembly opening of the piston assembly through a first valve; the fourth piston assembly opening of the piston assembly is connected to the seventh opening of the third three-way valve, the eighth opening of the third three-way valve is connected to the first nanofiltration opening of the nanofiltration system, the ninth opening of the third three-way valve is connected to the inlet of the first circulation pump, and the outlet of the second circulation pump is connected to the second piston assembly opening of the piston assembly through a second valve, wherein a piston is provided in the piston assembly, the first piston assembly opening of the piston assembly and the third piston assembly opening of the piston assembly are located on one side of the piston, the second piston assembly opening of the piston assembly and the fourth piston assembly opening of the piston assembly are located on the other side of the piston, and the nanofiltration system is provided with a nanofiltration membrane, and the first nanofiltration opening and the second nanofiltration opening of the nanofiltration system are respectively located at both ends of the nanofiltration membrane.

[0005] Optionally, it includes a first state, when the concentration system is in the first state, the first pump supplies liquid to the reverse osmosis system, the liquid passes through the reverse osmosis system to produce purified liquid and a first saline solution, the first saline solution passes through the first opening and the second opening of the first three-way valve in sequence to reach the first piston assembly opening of the piston assembly, the first saline solution pushes the piston in the piston assembly to move toward the side of the second piston assembly opening, so that the second saline solution in the piston assembly leaves from the fourth piston assembly opening and passes through the seventh opening and the eighth opening of the third three-way valve in sequence to reach the first nanofiltration opening of the nanofiltration system; the second saline solution passes through the nanofiltration membrane from one side of the first nanofiltration opening; the second saline solution leaves from the second nanofiltration opening and passes through the fifth opening and the sixth opening of the second three-way valve in sequence to reach the second circulation pump, and is pumped to the piston assembly by the second circulation pump.

[0006] Optionally, it includes a second state. When in the second state, the first pump supplies liquid to the reverse osmosis system, and the liquid passes through the reverse osmosis system to produce purified liquid and a third saline solution. The third saline solution passes through the first opening and the third opening of the first three-way valve in sequence to reach the second piston assembly opening of the piston assembly. The third saline solution pushes the piston in the piston assembly to move toward the side of the first piston assembly opening, so that the fourth saline solution in the piston assembly leaves from the third piston assembly opening and passes through the fourth opening and the fifth opening of the second three-way valve in sequence to reach the second nanofiltration opening of the nanofiltration system. The fourth saline solution passes through the nanofiltration membrane from one side of the second nanofiltration opening; the fourth saline solution leaves from the first nanofiltration opening and passes through the eighth opening and the ninth opening of the third three-way valve in sequence to reach the first circulation pump, and is pumped to the piston assembly by the first circulation pump.

[0007] Optionally, in the first state, the rate at which the second saline solution passes through the nanofiltration membrane is constant, and in the second state, the rate at which the fourth saline solution passes through the nanofiltration membrane is constant.

[0008] Optionally, it also includes a pumping device. When the concentration system is in the first waste liquid discharge state, the second saline solution is sucked out of the opening of the fourth piston assembly by the pumping device and passes through the third three-way valve and the nanofiltration membrane of the nanofiltration system in sequence, and is finally transported to the outside through the pumping device; when the concentration system is in the second waste liquid discharge state, the fourth saline solution is sucked out of the opening of the third piston assembly by the pumping device and passes through the second three-way valve and the nanofiltration membrane of the nanofiltration system in sequence, and is finally transported to the outside through the pumping device.

[0009] Optionally, a raw material tank is further included, the inlet of the raw material tank is connected to the first nanofiltration opening and the second nanofiltration opening of the nanofiltration system respectively, the outlet of the raw material tank is connected to the first pump, and conductivity meters are respectively provided at the inlet and outlet of the raw material tank.

[0010] Optionally, when the concentration system is in a cleaning state, the liquid is transported from the raw material tank to the reverse osmosis system and the high-pressure nanofiltration system in sequence under the action of the first pump, and finally returns to the raw material tank.

[0011] Optionally, a sodium bed is provided between the raw material tank and the first pump, and the sodium bed is used to remove calcium ions and magnesium ions in the liquid.

[0012] In a second aspect, the present disclosure provides a wastewater treatment method, which treats wastewater using the concentration system in any embodiment of the first aspect.

[0013] Optionally, the concentration system includes a first state, a second state, a first waste liquid discharge state, a second waste liquid discharge state and a cleaning state, and the concentration system changes in the order of the first state, the first waste liquid discharge state, the cleaning state, the second state, the second waste liquid discharge state and the cleaning state.

[0014] Through the coordination of the above structures, one or more circulation loops are formed, thereby increasing the brine concentration to a higher level under low operating pressure. At the same time, the above data are monitored by the electrical and automatic control system, and the operating pressure, flushing flow rate, flushing time and other information are optimized and fed back and adjusted in real time, which significantly reduces the energy consumption and cost of high-salt wastewater treatment and alleviates membrane pollution. It has important application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of a novel dynamic reverse osmosis and nanofiltration ultra-high concentration system in a certain embodiment of the present disclosure.

[0016] Figure 2 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the liquid injection state.

[0017] Figure 3 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the first state.

[0018] Figure 4 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the first waste liquid discharge state.

[0019] Figure 5 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the first cleaning state.

[0020] Figure 6 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the second state.

[0021] Figure 7 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the second waste liquid discharge state.

[0022] Figure 8 for Figure 1 Schematic diagram of the structure of the new dynamic reverse osmosis and nanofiltration ultra-high concentration system in the second cleaning state.

[0023] Symbols in the figure: 100, first pump; 200, reverse osmosis system; 210, first output port; 220, second output port; 310, first three-way valve; 311, first opening; 312, second opening; 313, third opening; 320, second three-way valve; 321, fourth opening; 322, fifth opening; 323, sixth opening; 330, third three-way valve; 331, seventh opening; 332, eighth opening; 333, ninth opening; 400, piston assembly; 410, first piston assembly opening; 420, second piston assembly opening; 430, third piston assembly opening Component opening; 440, fourth piston component opening; 450, piston; 500, nanofiltration system; 510, first nanofiltration opening; 520, second nanofiltration opening; 530, third nanofiltration opening; 600, first circulation pump; 700, second circulation pump; 810, pumping device; 820, raw material tank; 830, sodium bed; 840, concentrated liquid tank; 910, conductivity meter; 920, flow meter; 930, thermometer; 940, pressure gauge; 950, hardness tester; 960, first valve; 970, second valve; 980, first branch; 990, second branch. DETAILED DESCRIPTION

[0024] It should be understood that the exemplary embodiments described herein should be considered only for descriptive purposes and not for purposes of limitation. Descriptions of features or aspects in each exemplary embodiment should generally be considered applicable to similar features or aspects in other exemplary embodiments.

[0025] It should be noted that reverse osmosis is a widely used technology for deep wastewater treatment. However, the maximum concentration of brine is limited by the transmembrane pressure difference on both sides of the membrane. If the traditional reverse osmosis process is used, the operating pressure will far exceed the maximum pressure that the traditional reverse osmosis membrane element can withstand. Therefore, the new dynamic reverse osmosis and nanofiltration ultra-high concentration system proposed in this disclosure can increase the brine concentration to more than 250g / L (i.e., ultra-high concentration of wastewater) under the operating pressure of no more than 70bar, significantly reducing the energy consumption and cost of high-salt wastewater treatment, and has important application prospects.

[0026] Specifically, the present disclosure provides a novel dynamic reverse osmosis and nanofiltration ultra-high concentration system, such as Figure 1As shown, it includes a first pump 100 , a reverse osmosis system 200 , a first three-way valve 310 , a second three-way valve 320 , a third three-way valve 330 , a piston assembly 400 , a nanofiltration system 500 , a first circulation pump 600 and a second circulation pump 700 . The output port of the first pump 100 is in communication with the reverse osmosis system 200, the first output port 210 of the reverse osmosis system 200 is in communication with the outside, the second output port 220 of the reverse osmosis system 200 is in communication with the first opening 311 of the first three-way valve 310, the second opening 312 of the first three-way valve 310 is in communication with the first piston assembly opening 410 of the piston assembly 400, the third opening 313 of the first three-way valve 310 is in communication with the second piston assembly opening 420 of the piston assembly 400, the third piston assembly opening 430 of the piston assembly 400 is in communication with the fourth opening 321 of the second three-way valve 320, the fifth opening 322 of the second three-way valve 320 is in communication with the second nanofiltration opening 520 of the nanofiltration system 500, the sixth opening 323 of the second three-way valve 320 is in communication with the inlet of the second circulation pump 700, and the outlet of the second circulation pump 700 is in communication with the second piston assembly opening 420 of the piston assembly 400 through the second valve 970; 0 is connected to the seventh opening 331 of the third three-way valve 330, the eighth opening 332 of the third three-way valve 330 is connected to the first nanofiltration opening 510 of the nanofiltration system 500, and the ninth opening 333 of the third three-way valve 330 is connected to the inlet of the first circulation pump 600. The outlet of the first circulation pump 600 is connected to the first piston assembly opening 410 of the piston assembly 400 through the first valve 960. The piston assembly 400 is provided with a piston 450, the first piston assembly opening 410 of the piston assembly 400 and the third piston assembly opening 430 of the piston assembly 400 are located on one side of the piston 450, the second piston assembly opening 420 of the piston assembly 400 and the fourth piston assembly opening 440 of the piston assembly 400 are located on the other side of the piston 450, and the nanofiltration system 500 is provided with a nanofiltration membrane, and the first nanofiltration opening 510 and the second nanofiltration opening 520 of the nanofiltration system 500 are respectively located at both ends of the nanofiltration membrane.

[0027] It should be noted that reverse osmosis system 200 includes a reverse osmosis membrane, which purifies the water by intercepting salts, minerals, and harmful substances in the liquid to produce a purified liquid. Residues that are difficult to purify are discharged to form a saline solution. Specifically, the reverse osmosis membrane includes, but is not limited to, a seawater reverse osmosis desalination membrane element, such as the SW-8040 desalination membrane.

[0028] The nanofiltration system 500 is equipped with a nanofiltration membrane that uses pressure to separate the solvent in the solution through the nanofiltration membrane, mainly targeting monovalent salts (such as sodium ions) in the liquid of the nanofiltration system 500. The nanofiltration membrane can be a high-pressure nanofiltration membrane element, such as the NF-8040 nanofiltration membrane.

[0029] The first saline solution, the second saline solution, the third saline solution and the fourth saline solution are all saline solutions, that is, solutions containing salt (a compound composed of metal ions (including ammonium ions) and acid ions).

[0030] More specifically, the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system further includes a raw material tank 820 and a liquid pumping device 810. The raw material tank 820 is connected to the input port of the first pump 100, so liquid can be transported from the raw material tank 820 to the reverse osmosis system 200 via the first pump 100. The liquid pumping device 810 is connected to the first nanofiltration opening 510 and the second nanofiltration opening 520 of the nanofiltration system 500 via pipelines. Liquid in the nanofiltration system 500 can be pumped by the liquid pumping device 810 to a concentrate tank 840 for storage.

[0031] It should be noted that, in some optional embodiments, the raw material tank 820 is connected to the first nanofiltration opening 510 and the second nanofiltration opening 520 of the nanofiltration system 500 through pipelines, and the liquid passing through the nanofiltration system 500 can be transported to the raw material tank 820 through the pipelines.

[0032] In some optional embodiments, the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system includes a liquid injection state, such as Figure 2 As shown, in the liquid injection state, the liquid is transported from the raw material tank 820 to the reverse osmosis system 200 under the action of the first pump 100. The reverse osmosis system 200 processes the liquid to obtain a purified liquid and a second saline solution. The second saline solution sequentially passes through the first opening 311 and the third opening 313 of the first three-way valve 310 to reach the second piston assembly opening 420 of the piston assembly 400. The second saline solution pushes the piston 450 in the piston assembly 400 to move toward the side of the first piston assembly opening 410, so that the second saline solution fills the entire piston assembly 400.

[0033] It should be noted that the second circulation pump is turned off and the second valve 970 at the outlet of the second circulation pump is tightly closed at this time.

[0034] In some optional embodiments, the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system includes a first state. When the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system is in the first state, the first pump 100 supplies liquid to the reverse osmosis system 200. The liquid passes through the reverse osmosis system 200 to produce purified liquid and a first saline solution. The first saline solution passes through the first opening 311 and the second opening 312 of the first three-way valve 310 in sequence to reach the first piston assembly opening 410 of the piston assembly 400. The first saline solution pushes the piston 450 in the piston assembly 400 to move toward the side of the second piston assembly opening 420, so that the piston assembly The second saline in 400 leaves from the fourth piston assembly opening 440 and passes through the seventh opening 331 and the eighth opening 332 of the third three-way valve 330 in sequence to reach the first nanofiltration opening 510 of the nanofiltration system 500; the second saline passes through the nanofiltration membrane from one side of the first nanofiltration opening 510; the second saline leaves from the second nanofiltration opening 520 and passes through the fifth opening 322 and the sixth opening 323 of the second three-way valve 320 in sequence to reach the second circulation pump 700, and is pumped to the second piston assembly opening 420 of the piston assembly 400 by the second circulation pump 700 to be delivered into the piston assembly 400, as shown in FIG. Figure 3 At this time, the valve at the outlet of the second circulation pump is in the open state.

[0035] It should be noted that, optionally, the nanofiltration system 500 further includes a third nanofiltration opening 530, through which the liquid (second saline solution) in the nanofiltration system 500 can be transported to the inlet of the sodium bed 830 and re-enter the circulation. It should be noted that the sodium bed 830 is disposed between the raw material tank 820 and the first pump 100, and the liquid in the raw material tank 820 enters the sodium bed 830 through the inlet of the sodium bed 830 to remove calcium ions and magnesium ions in the liquid. The treated liquid is then transported to the first pump 100 through the outlet of the sodium bed 830.

[0036] In the above scheme, two circulation loops can actually be formed in the first state. The first circulation loop runs from the piston assembly 400 to the nanofiltration system 500, then to the second circulating pump 700, and finally back to the piston assembly 400. In the first circulation loop, since the saline solution continuously flows from the piston assembly 400 to the nanofiltration system 500 and then back to the piston assembly 400, this ensures that the saline solution concentration difference on both sides of the nanofiltration membrane in the nanofiltration system 500 is not too large, and thus it is no longer necessary to provide higher pressure to the nanofiltration system 500. Specifically, if the saline solution concentration difference on both sides of the nanofiltration membrane is too large, the operating pressure of the pump required to produce constant water will increase, and the nanofiltration membrane (the membrane material itself has a pressure limit) cannot withstand such high pressure and may be damaged and ruptured. The second circulation loop is from the sodium bed 830, the first pump 100, the reverse osmosis system 200, the piston assembly 400, the nanofiltration system 500, and finally back to the sodium bed 830. In this system, the liquid can circulate continuously, reducing the pressure difference on both sides of the reverse osmosis membrane in the reverse osmosis system 200. At the same time, the arrangement of the piston assembly 400 can effectively convert the pressure provided by the first pump 100 into the power for the movement of the piston, thereby reducing the operating pressure of the entire system to a certain extent.

[0037] In some optional embodiments, the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system further includes a pumping device 810. When the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system is in the first waste liquid discharge state, the second saline solution is sucked out of the fourth piston assembly opening 440 by the pumping device 810 and passes through the seventh opening 331 and the eighth opening 332 of the third three-way valve 330 and the nanofiltration membrane of the nanofiltration system 500 in sequence, and is finally transported to the outside through the pumping device 810. For example, it can be finally transported to the concentrated liquid tank 840 for storage, as shown in FIG. Figure 4 At this time, the first valve 960 and the second valve 970 should be in a closed state.

[0038] When the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system is in the second waste liquid discharge state, the fourth salt solution is sucked out from the third piston assembly opening 430 by the pumping device 810 and sequentially passes through the fourth opening 321 and the fifth opening 322 of the second three-way valve 320 and the nanofiltration membrane of the nanofiltration system 500, and is finally transported to the outside through the pumping device 810, such as to be finally transported to the concentrated liquid tank 840 for storage, as shown in FIG. Figure 7 At this time, the first valve 960 and the second valve 970 should be in a closed state.

[0039] Specifically, the liquid extraction device 810 is connected to the first nanofiltration opening 510 and the second nanofiltration opening 520 of the nanofiltration system 500 through the first branch 980 and the second branch 990, respectively, and valves are provided in the first branch 980 and the second branch 990. Under normal circumstances, the valves of the first branch 980 and the second branch 990 are normally closed. However, in the first waste liquid discharge state, the valve of the first branch 980 is closed and the valve of the second branch 990 is open, as shown in FIG. Figure 4 The second saline solution exits from the fourth piston assembly opening 440 and sequentially passes through the seventh opening 331 and the eighth opening 332 of the third three-way valve 330 to reach the first nanofiltration opening 510 of the nanofiltration system 500, passes through the nanofiltration membrane of the nanofiltration system 500 to reach the second nanofiltration opening 520, and is then transported to the concentrate tank 840 through the second branch 990.

[0040] In the second waste liquid discharge state, the valve of the first branch 980 is open and the valve of the second branch 990 is closed. Figure 7 At this time, the fourth saline solution leaves the third piston assembly opening 430 and passes through the fourth opening 321 and the fifth opening 322 of the second three-way valve 320 in sequence to reach the second nanofiltration opening 520 of the nanofiltration system 500, and then passes through the nanofiltration membrane to reach the first nanofiltration opening 510, and is finally transported to the concentrate tank 840 through the pumping device 810.

[0041] Optionally, the inlet of the raw material tank 820 is connected to the first nanofiltration opening 510 and the second nanofiltration opening 520 of the nanofiltration system 500 respectively, the outlet of the raw material tank 820 is connected to the first pump 100, and a conductivity meter 910 is provided at the inlet and outlet of the raw material tank 820 respectively.

[0042] Optionally, when the new dynamic reverse osmosis and nanofiltration ultra-high concentration system is in a cleaning state, the liquid is transported from the raw material tank 820 to the reverse osmosis system 200 and the high-pressure nanofiltration system 500 in sequence under the action of the first pump 100, and finally returns to the raw material tank 820.

[0043] More specifically, the cleaning state is divided into a first cleaning state and a second cleaning state. In the first cleaning state, the liquid is transported from the raw material tank 820 to the reverse osmosis system 200 under the action of the first pump 100, and then is transported to the second piston assembly opening 420 of the piston assembly 400 through the first three-way valve 310, and then passes through the fourth piston assembly opening 440, the third three-way valve 330, the first nanofiltration opening 510 of the nanofiltration system 500, the nanofiltration membrane and the second nanofiltration opening 520, and finally returns to the raw material tank 820. For details, please refer to Figure 5 At this time, purified liquid can also be produced when flowing through the reverse osmosis system 200.

[0044] In the second cleaning state, the liquid is transported from the raw material tank 820 to the reverse osmosis system 200 under the action of the first pump 100, and then is transported to the first piston assembly opening 410 of the piston assembly 400 through the first three-way valve 310, and then passes through the third piston assembly opening 430, the second three-way valve 320, the second nanofiltration opening 520 of the nanofiltration system 500, the nanofiltration membrane and the first nanofiltration opening 510 in sequence, and finally returns to the raw material tank 820. For details, please refer to Figure 8 At this time, purified liquid can also be produced when flowing through the reverse osmosis system 200.

[0045] In some optional embodiments, the novel dynamic reverse osmosis and nanofiltration ultra-high concentration system includes a second state, such as Figure 6 As shown, when in the second state, the first pump 100 supplies liquid to the reverse osmosis system 200, and the liquid produces purified liquid and a third saline solution through the reverse osmosis system 200. The third saline solution sequentially passes through the first opening 311 and the third opening 313 of the first three-way valve 310 to reach the second piston assembly opening 420 of the piston assembly 400. The third saline solution pushes the piston 450 in the piston assembly 400 to move toward one side of the first piston assembly opening 410, so that the fourth saline solution in the piston assembly 400 leaves from the third piston assembly opening 430 and sequentially passes through the fourth opening 321 and the fifth opening 322 of the second three-way valve 320 to reach the second nanofiltration opening 520 of the nanofiltration system 500, and the fourth saline solution passes through the nanofiltration membrane from one side of the second nanofiltration opening 520; the fourth saline solution leaves from the first nanofiltration opening 510 and sequentially passes through the eighth opening 332 and the ninth opening 333 of the third three-way valve 330 to reach the first circulation pump 600, and is pumped to the piston assembly 400 by the first circulation pump 600.

[0046] Optionally, the liquid (fourth saline solution) in the nanofiltration system 500 can be transported to the inlet of the sodium bed 830 through the third nanofiltration opening 530 and re-enter the circulation.

[0047] In such scheme, in fact, in the second state, two sets of circulation loops can be formed. The first set of circulation loop is from piston assembly 400 to nanofiltration system 500, and then to the second recycle pump 600, and finally returns to the piston assembly 400. In the first set of circulation loop, because saline solution can constantly go to nanofiltration system 500 from piston assembly 400 and then return to piston assembly 400, it is ensured that the saline solution concentration difference on nanofiltration membrane both sides in nanofiltration system 500 can not be too large like this, and then no longer need to provide higher pressure to nanofiltration system 500. The second set of circulation loop then finally returns to sodium bed 830 from sodium bed 830, the first pump 100, reverse osmosis system 200, piston assembly 400, nanofiltration system 500.

[0048] In the first state, the second salt solution passes through the nanofiltration membrane at a constant rate, and in the second state, the fourth salt solution passes through the nanofiltration membrane at a constant rate. By stabilizing the speed at which the salt solution passes through the nanofiltration membrane, the influence of concentration polarization on the membrane surface is reduced.

[0049] At the same time, if Figure 1 As shown, optionally, a conductivity meter 910 and a flow meter 920 may be installed at the first output port 210 of the reverse osmosis system 200. A conductivity meter 910, a flow meter 920, and a thermometer 930 may also be installed between the outlet of the raw material tank 820 and the sodium bed 830 to monitor the conductivity, flow rate, and temperature of the liquid flowing out of the raw material tank 820. A hardness tester 950 may be installed between the sodium bed 830 and the first pump 100 to monitor the hardness of the liquid flowing out of the sodium bed 830. A pressure gauge 940 may be installed at the second output port 220 of the reverse osmosis system 200 to monitor the pressure of the liquid flowing out of the second output port 220 of the reverse osmosis system 200. A conductivity meter 910 and a flow meter 920 may be installed in the pipeline connecting the third nanofiltration opening 530 of the nanofiltration system 500 and the sodium bed 830.

[0050] In addition, the present disclosure provides a wastewater treatment method, which treats wastewater through a new dynamic reverse osmosis and nanofiltration ultra-high concentration system. The new dynamic reverse osmosis and nanofiltration ultra-high concentration system includes a first state, a second state, a first waste liquid discharge state, a second waste liquid discharge state, and a cleaning state. The new dynamic reverse osmosis and nanofiltration ultra-high concentration system changes in the order of the first state, the first waste liquid discharge state, the cleaning state, the second state, the second waste liquid discharge state, and the cleaning state. More specifically, the new dynamic reverse osmosis and nanofiltration ultra-high concentration system includes a first state, a second state, a first waste liquid discharge state, a second waste liquid discharge state, a first cleaning state, and a second cleaning state. The new dynamic reverse osmosis and nanofiltration ultra-high concentration system changes in the order of the first state, the first waste liquid discharge state, the first cleaning state, the second state, the second waste liquid discharge state, and the second cleaning state.

[0051] In the first state, to ensure a constant rate of passage of the second saline solution through the nanofiltration membrane in the nanofiltration system 500, the power of the first pump 100 is continuously increased to ensure sufficient output pressure. When the power of the first pump 100 reaches a specified power (usually a maximum power), the first state ends and the first pump 100 is turned off. The system then enters the first waste liquid discharge state.

[0052] In addition to terminating the first state when the first pump 100 reaches a specified power, the first state can also be terminated when the system recovery rate reaches a specified recovery rate. The recovery rate is calculated by combining the flow rate data measured by the flow meter 920 on the side of the reverse osmosis system 200 that produces the purified liquid with the total volume of the nanofiltration system and the circulation loop.

[0053] In the first waste liquid discharge state, after the pumping device 810 pumps all the salt solution in the nanofiltration system and the piston assembly 400 into the concentrated liquid tank 840, it switches to the first cleaning state. It should be noted that at this time, the first pump 100 is closed, the first three-way valve 310 and the second three-way valve 320 are closed. For details, please refer to Figure 4 .

[0054] In the first cleaning state, a conductivity meter 910 is provided in the pipeline from the nanofiltration system 500 to the raw material tank 820, thereby detecting the conductivity of the saline solution in the pipeline. Specifically, a pipeline is provided between the second nanofiltration opening of the nanofiltration system 500 and the raw material tank 820, and the conductivity meter 910 is provided on the pipeline.

[0055] When the conductivity value of the cleaning liquid recorded on the conductivity meter 910 changes significantly, it proves that there is still concentrated liquid remaining in the pipeline. Continue to increase the cleaning flow rate or increase the cleaning time until the conductivity value stabilizes, indicating that the concentrated liquid in the pipeline has been completely cleaned. At this time, the first cleaning state ends and enters the second state.

[0056] In the second state, in order to ensure that the rate at which the fourth saline solution in the nanofiltration system 500 passes through the nanofiltration membrane is constant, the power of the first pump 100 is continuously increased to ensure that the output pressure is sufficient. When the power of the first pump 100 reaches the specified specified power, the first state ends and the first pump 100 is turned off. Enter the second waste liquid discharge state. Of course, in some embodiments, the first state can also be ended after the recovery rate reaches the preset value, and the first pump 100 is turned off. It should be noted that, in some embodiments, the fourth saline solution at this time can be understood as the saline solution on one side of the third piston assembly opening 430 remaining in the piston assembly 400 after the first cleaning state ends.

[0057] In the second waste liquid discharge state, after the pumping device 810 pumps all the salt solution in the nanofiltration system and the piston assembly 400 into the concentrated liquid tank 840, it switches to the second cleaning state. It should be noted that at this time, the first pump 100 is closed, the first three-way valve 310 and the third three-way valve 330 are closed. For details, please refer to Figure 7 .

[0058] During the second cleaning state, a conductivity meter 910 is installed in the pipeline from the nanofiltration system 500 to the raw material tank 820, allowing the conductivity of the saline solution in the pipeline to be measured. Specifically, a pipeline is provided between the first nanofiltration opening of the nanofiltration system 500 and the raw material tank 820, and the conductivity meter 910 is installed on this pipeline. If the conductivity value of the cleaning solution recorded by the conductivity meter 910 changes significantly, it indicates that the concentrated solution in the pipeline is still present. The cleaning flow rate or cleaning time is increased until the conductivity value stabilizes, indicating that the concentrated solution in the pipeline has been completely cleaned, at which point the second cleaning state ends.

[0059] In addition, the new dynamic reverse osmosis and nanofiltration ultra-high concentration system is equipped with various high-precision measurement sensors (such as conductivity meter 910, flow meter 920, and thermometer 930) to measure and collect data such as flow rate, pressure, conductivity, and temperature of the influent and produced water at each stage. The electrical and automatic control system monitors this data, optimizes feedback, and makes real-time adjustments to operating pressure, flushing flow rate, and flushing time.

[0060] Flowmeter 920 can also monitor the water flow rate in the high-pressure nanofiltration system. As the nanofiltration system continues to operate, the brine concentration in the pipeline increases. To maintain a constant water output, the operating pressure must be gradually increased. When the electrical and automatic control system detects a decrease in water production from the nanofiltration system via flowmeter 920, it automatically increases the power of first pump 100, optimizes the feedback operating pressure, and makes real-time adjustments to ensure a constant water output from the nanofiltration system.

[0061] Specifically, the operating pressure can be controlled by formula (1), which means that when the square of the difference between the real-time measured water production flow rate and the system set water production flow rate is minimized, the operating pressure is the optimal operating pressure.

[0062]

[0063] Among them, P in (t) represents the operating pressure of the high-pressure pump, the unit is MPa; Q P,0 Respectively represent the real-time measured water flow rate and the specified water flow rate, the unit is m 3 / h. Q P,0 , the specified water production flow rate is the preset value.

[0064] A conductivity meter 910 is also deployed to monitor the ionic conductivity of the cleaning fluid in real time. If the cleaning fluid conductivity value recorded by conductivity meter 910 fluctuates significantly, it indicates that concentrated liquid remains in the pipeline. The cleaning flow rate or cleaning time should be increased until the conductivity value stabilizes, indicating that the concentrated liquid in the pipeline has been completely removed and the cleaning process is complete.

[0065] The cleaning time can be controlled by formula (2), which means that the cleaning is completed when the change of the conductivity of the concentrated solution outlet measured in real time within a certain interval is less than the set tolerance.

[0066]

[0067] Among them, σ b (t+Δt),σ b(t) represents the conductivity of the outlet solution at time t+Δt and time t in the cleaning stage, respectively, and its unit is S / m; ε represents the set tolerance; Δt represents the time interval between adjacent data transmissions by the sensor, and its unit is s.

[0068] In addition, an appropriate amount of high-efficiency descaling agent (including but not limited to PTP-0100) can be added to the raw material tank 820 to increase the concentration limit of each ion in the water sample.

[0069] A descaling agent (including but not limited to PTP-0100) may be added to the sodium bed 830 to remove calcium, magnesium, silicon, aluminum, and other ions.

[0070] The operating pressure of the first pump 100 is a variable dynamic operating pressure.

[0071] The ultra-high concentration technology developed in this patented invention can raise the brine concentration to over 250 g / L (with NaCl as the solute) at an operating pressure of no more than 70 bar, while conventional reverse osmosis technology can only concentrate to a maximum of approximately 80 g / L. This technology can significantly reduce the energy consumption and cost of high-salinity wastewater treatment and has important application prospects. We have analyzed the operating parameters and economic benefits of this patented technology compared with conventional reverse osmosis technology (see Table 1). Assuming a feed flow rate of 20 m³ / h and a total dissolved solids content of 36 g / L (with NaCl as the solute), the total amount of brine fed to the evaporation process is expected to be reduced by over 80% (from 9.0 m³ / h to 2.8 m³ / h) using the new ultra-high concentration technology described in this patent. The total electricity cost of the evaporation process is 6.05 million yuan per year (calculated based on 300 operating days per year), a reduction of over 80% compared to conventional reverse osmosis technology (saving over 13.39 million yuan). This technology is mainly aimed at the zero wastewater discharge process, which further concentrates the high-concentration brine before it is sent to the evaporation device without affecting the factory's original conventional reverse osmosis concentration process.

[0072]

[0073]

[0074] Taking high-concentration brine (NaCl) as an example, under typical operating pressure (70 bar), the concentrate (i.e., the liquid placed in concentrate tank 840) can only reach a concentration of 82 g / L. The novel dynamic reverse osmosis and nanofiltration ultra-high concentration system proposed in this patent can increase the brine concentration to over 250 g / L at an operating pressure not exceeding 70 bar.

[0075] Compared to traditional continuous-feed reverse osmosis processes, the dynamic reverse osmosis process proposed in this patent includes a flushing process within each cycle, effectively mitigating membrane fouling. Determining the optimal flushing time is crucial for the proper operation of the system. First, a too-short flushing time results in incomplete cleaning of the pipelines. Furthermore, as the system cycles, the concentration of brine processed by the nanofiltration system increases, ultimately leading not only to scale buildup that clogs the pipelines and membrane channels but also to increased operating pressure, further increasing system energy consumption. Second, the brine concentration entering the nanofiltration system is relatively low during the early stages of operation, when the pump's operating pressure and the nanofiltration membrane's compressive strength meet the required production flow rate. However, if the flushing time is too short, the brine concentration will continue to rise later. While maintaining the same production flow rate or recovery rate, the operating pressure will exceed the pump's normal operating pressure and the nanofiltration membrane's compressive strength limit, impacting the proper operation of the entire system. Conversely, while increasing the flushing time can mitigate membrane fouling, it also increases the concentration system's operating cycle, reducing overall process efficiency. Therefore, optimizing the flushing time is a key innovation of this process.

[0076] The new dynamic reverse osmosis and nanofiltration ultra-high concentration system proposed in this patent can increase the brine concentration to above 250g / L under the operating pressure not exceeding 70bar. At the same time, the entire process is divided into multiple stages according to the flow. The above data is monitored by the electrical and automatic control system, and the operating pressure, flushing flow rate, flushing time and other information are optimized and fed back and adjusted in real time, which significantly reduces the energy consumption and cost of high-salt wastewater treatment and alleviates membrane pollution. It has important application prospects.

[0077] Obviously, the above embodiments of the present disclosure are merely examples for the purpose of clearly illustrating the present disclosure, and are not intended to limit the implementation methods of the present disclosure. For those skilled in the art, other variations or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the claims of the present disclosure.

Claims

1. A new type of dynamic reverse osmosis and nanofiltration ultra-high concentration system, characterized in that: The invention comprises a first pump (100), a reverse osmosis system (200), a first three-way valve (310), a second three-way valve (320), a third three-way valve (330), a piston assembly (400), a nanofiltration system (500), a first circulation pump (600) and a second circulation pump (700), wherein the output port of the first pump (100) is in communication with the reverse osmosis system (200), the first output port (210) of the reverse osmosis system (200) is in communication with the outside, the second output port (220) of the reverse osmosis system (200) is in communication with the first opening (311) of the first three-way valve (310), the second opening (312) of the first three-way valve (310) is in communication with the outside, and the third three-way valve (330) is in communication with the first three-way valve (310). The first piston assembly opening (410) of the piston assembly (400) is in communication, the third opening (313) of the first three-way valve (310) is in communication with the second piston assembly opening (420) of the piston assembly (400), the third piston assembly opening (430) of the piston assembly (400) is in communication with the fourth opening (321) of the second three-way valve (320), the fifth opening (322) of the second three-way valve (320) is in communication with the second nanofiltration opening (520) of the nanofiltration system (500), the sixth opening (323) of the second three-way valve (320) is in communication with the inlet of the second circulation pump (700), and the inlet of the second circulation pump (700) is in communication with the inlet of the second circulation pump (700). The outlet is communicated with the second piston assembly opening (420) of the piston assembly (400) through the second valve (970); the fourth piston assembly opening (440) of the piston assembly (400) is communicated with the seventh opening (331) of the third three-way valve (330); the eighth opening (332) of the third three-way valve (330) is communicated with the first nanofiltration opening (510) of the nanofiltration system (500); the ninth opening (333) of the third three-way valve (330) is communicated with the inlet of the first circulation pump (600); the outlet of the first circulation pump (600) is communicated with the first piston assembly opening ( 410), wherein the piston assembly (400) is provided with a piston (450), the first piston assembly opening (410) of the piston assembly (400) and the third piston assembly opening (430) of the piston assembly (400) are located on one side of the piston (450), the second piston assembly opening (420) of the piston assembly (400) and the fourth piston assembly opening (440) of the piston assembly (400) are located on the other side of the piston (450), and the nanofiltration system (500) is provided with a nanofiltration membrane, and the first nanofiltration opening (510) and the second nanofiltration opening (520) of the nanofiltration system (500) are respectively located at both ends of the nanofiltration membrane.

2. The concentration system according to claim 1, characterized in that The invention comprises a first state, wherein when the concentration system is in the first state, the first pump (100) supplies liquid to the reverse osmosis system (200), the liquid passes through the reverse osmosis system (200) to produce purified liquid and a first saline solution, the first saline solution sequentially passes through the first opening (311) and the second opening (312) of the first three-way valve (310) to reach the first piston assembly opening (410) of the piston assembly (400), the first saline solution pushes the piston (450) in the piston assembly (400) to move toward the side of the second piston assembly opening (420), so that the second saline solution in the piston assembly (400) is The liquid leaves the fourth piston assembly opening (440) and passes through the seventh opening (331) and the eighth opening (332) of the third three-way valve (330) in sequence to reach the first nanofiltration opening (510) of the nanofiltration system (500); the second saline solution passes through the nanofiltration membrane from one side of the first nanofiltration opening (510); the second saline solution leaves the second nanofiltration opening (520) and passes through the fifth opening (322) and the sixth opening (323) of the second three-way valve (320) in sequence to reach the second circulation pump (700), and is pumped to the piston assembly (400) by the second circulation pump (700).

3. The concentration system according to claim 2, characterized in that The invention comprises a second state, wherein when in the second state, the first pump (100) supplies liquid to the reverse osmosis system (200), the liquid passes through the reverse osmosis system (200) to produce purified liquid and a third saline solution, the third saline solution sequentially passes through the first opening (311) and the third opening (313) of the first three-way valve (310) to reach the second piston assembly opening (420) of the piston assembly (400), the third saline solution pushes the piston (450) in the piston assembly (400) to move toward one side of the first piston assembly opening (410), so that the fourth saline solution in the piston assembly (400) is discharged from the first piston assembly (420). The fourth saline solution leaves the third piston assembly opening (430) and passes through the fourth opening (321) and the fifth opening (322) of the second three-way valve (320) in sequence to reach the second nanofiltration opening (520) of the nanofiltration system (500), and the fourth saline solution passes through the nanofiltration membrane from one side of the second nanofiltration opening (520); the fourth saline solution leaves the first nanofiltration opening (510) and passes through the eighth opening (332) and the ninth opening (333) of the third three-way valve (330) in sequence to reach the first circulation pump (600), and is pumped to the piston assembly (400) by the first circulation pump (600).

4. The concentration system according to claim 3, characterized in that In the first state, the rate at which the second saline solution passes through the nanofiltration membrane is constant. In the second state, the rate at which the fourth saline solution passes through the nanofiltration membrane is constant.

5. The concentration system according to claim 3, characterized in that The system further comprises a pumping device (810). When the concentration system is in the first waste liquid discharge state, the second saline solution is sucked out from the fourth piston assembly opening (440) by the pumping device (810) and sequentially passes through the third three-way valve (330) and the nanofiltration membrane of the nanofiltration system (500), and is finally transported to the outside through the pumping device (810). When the concentration system is in the second waste liquid discharge state, the fourth saline solution is sucked out from the third piston assembly opening (430) by the pumping device (810) and passes through the second three-way valve (320) and the nanofiltration membrane of the nanofiltration system (500) in sequence and is finally transported to the outside through the pumping device (810).

6. The concentration system according to claim 1, characterized in that The invention also includes a raw material tank (820), wherein the inlet of the raw material tank (820) is respectively connected to the first nanofiltration opening (510) and the second nanofiltration opening (520) of the nanofiltration system (500), and the outlet of the raw material tank (820) is connected to the first pump (100). Conductivity meters (910) are respectively provided at the inlet and outlet of the raw material tank (820).

7. The concentration system according to claim 6, characterized in that When the concentration system is in a cleaning state, the liquid is transported from the raw material tank (820) to the reverse osmosis system (200) and the high-pressure nanofiltration system (500) in sequence under the action of the first pump (100), and finally returns to the raw material tank (820).

8. The concentration system according to claim 1, characterized in that A sodium bed (830) is provided between the raw material tank (820) and the first pump (100), and the sodium bed (830) is used to remove calcium ions and magnesium ions in the liquid.

9. A wastewater treatment method, characterized in that: The wastewater is treated by the concentration system according to any one of claims 1 to 8.

10. The wastewater treatment method according to claim 9, characterized in that: The concentration system includes a first state, a second state, a first waste liquid discharge state, a second waste liquid discharge state and a cleaning state. The concentration system changes in the order of the first state, the first waste liquid discharge state, the cleaning state, the second state, the second waste liquid discharge state and the cleaning state.

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