CN114590915A

CN114590915A - Filtering unit and water treatment system

Info

Publication number: CN114590915A
Application number: CN202210150827.5A
Authority: CN
Inventors: 李世琪; 刘奎东
Original assignee: Xinjiang Shenbang Environmental Engineering Co ltd
Current assignee: Xinjiang Shenbang Environmental Engineering Co ltd
Priority date: 2022-02-18
Filing date: 2022-02-18
Publication date: 2022-06-07

Abstract

The application provides a filter unit for handle reverse osmosis filter's dense water, filter unit includes a pipe network formula reverse osmosis membrane subassembly and an at least nanofiltration membrane module, reverse osmosis filter's dense water gets into a post processing apparatus after a pipe network formula reverse osmosis membrane subassembly and an at least nanofiltration membrane module are concentrated. This application is through rational design the subassembly and the filtration order of filter unit realize carrying out efficient desalination to reverse osmosis filter equipment's dense water to the output equivalent normal water can supply the retrieval and utilization, with the water yield that reduces follow-up entering MVR evaporimeter remarkably, and then realize effectively reducing the whole energy consumption of handling, finally reach energy saving and emission reduction's purpose.

Description

Filtering unit and water treatment system

Technical Field

The application relates to the field of sewage and wastewater treatment, in particular to a filtering unit and a water treatment system for treating concentrated water of a reverse osmosis filtering device.

Background

The textile industry wastewater of China accounts for 8-10% of the total amount of the industrial wastewater and is the third place in the industrial industry. The waste water amount of the printing and dyeing industry accounts for about 80% of the total amount of the textile industry, the concentration of organic matters is high, the chromaticity is deep, and the treatment of the high-salt and high-chromaticity cotton printing and dyeing waste water is one of the difficult problems in the industrial waste water treatment, and the development of the textile industry is more seriously challenged.

Reactive dyes are commonly used for dyeing cotton textiles, and a large amount of salt is required to be added in the dyeing process to dye the dyes, and then the dyes are fixed on cotton fibers. The amount of the salt can be as high as 0.8-1.2 tons per ton of the product, and the dyeing residual liquid discharged after dyeing and subsequent washing liquid comprise a large amount of sodium sulfate or sodium chloride, hydrolytic reactive dye and the like. The water consumption in the cotton dyeing process is about 80-120 tons per ton of cotton. Therefore, the salt concentration in the cotton printing and dyeing wastewater can reach 6-12 g/L.

The conventional sewage treatment system for cotton printing and dyeing wastewater cannot remove salt, so that the cotton printing and dyeing wastewater after biochemical treatment needs to be subjected to advanced treatment by a Reverse Osmosis (RO) membrane system to produce reclaimed water (the salt content is less than 0.5g/L) which can be recycled. However, the conventional reverse osmosis membrane system is difficult to treat high-salinity wastewater, and after the cotton dyeing wastewater is treated, the produced reclaimed water is only 40-50% of the water inflow, and the discharged concentrated water (with the salt content of 10-30 g/L) is 50-60% of the water inflow.

At present, in order to realize zero discharge of cotton printing and dyeing wastewater, a conventional sewage treatment system for the cotton printing and dyeing wastewater is improved. Fig. 1 shows a conventional treatment system 10 for cotton dyeing wastewater, and as shown in fig. 1, this treatment system 10 is provided with a concentration treatment device 13 for treating concentrated water discharged from a reverse osmosis membrane after a reverse osmosis membrane system 12. The concentration device 13 is typically an electrodialysis membrane device (ED), a disk-and-tube reverse osmosis membrane Device (DTRO), or a pipe-and-net reverse osmosis membrane device (STRO). In the treatment system 1 shown in fig. 1, after the concentrated water of the reverse osmosis membrane system 12 is further concentrated by the concentration treatment device 13, the concentrated water enters the MVR evaporator 14 to evaporate water, and finally salt and other impurities are precipitated to be solid waste and discharged.

However, in actual operation, the treatment system 10 shown in fig. 1 has the following problems:

(1) comparing the energy consumption of the concentration treatment device 13 with that of the MVR evaporator 14, the applicant found that: the latter consumes far more energy than the former, and it can be seen that: i) although the concentrated water of the reverse osmosis membrane system 12 is concentrated by the concentration treatment device 13, the effect is not obvious, and the operation energy consumption of the MVR evaporator 14 cannot be effectively reduced, so that the overall energy consumption of the treatment system 10 cannot be effectively reduced; ii) effectively reducing the energy consumption of the MVR evaporator 14 is critical to achieving effective reduction of the overall energy consumption of the processing system 10;

(2) the treatment system 10 exhibits a low concentration capacity for the concentrate discharged by the reverse osmosis membrane system 12 and is unable to effectively reduce the evaporation capacity of the MVR evaporator 14;

(3) comparing the investment and running cost of the ED device, the DTRO device and the STRO device with the corresponding concentration effect, wherein the investment and running cost of the ED device and the DTRO device are higher than those of the STRO device, and the concentration effect (about 70-80%) is better than that of the STRO device; however, since the STRO apparatus has low investment and running costs, but has poor concentration efficiency (< 60%), it is still impossible to reduce the overall energy consumption of the treatment system 10 if the STRO apparatus is used as the concentration treatment apparatus 13.

Therefore, a new water treatment system is needed to be provided, so that the defects are overcome, the evaporation capacity of the MVR evaporator is reduced, the treatment energy consumption of the cotton printing and dyeing wastewater is reduced on the whole, and energy conservation and emission reduction are realized.

Disclosure of Invention

The utility model aims to provide a filter unit and water treatment system, through rational design filter unit's subassembly and filtration order realize carrying out efficient desalination to reverse osmosis filter equipment's dense water and output normal water to reduce the follow-up water yield that gets into the MVR evaporimeter remarkably, and then realize effectively reducing whole processing energy consumption, finally reach energy saving and emission reduction's purpose.

In order to achieve the above object, according to one aspect of the present application, there is provided a filter unit for treating concentrate (B) of a reverse osmosis filter device_ro) Wherein the filtration unit comprises a pipe-network type reverse osmosis membrane module and at least one nanofiltration membrane module, and the concentrated water (B) of the reverse osmosis filtration device_ro) Warp beamAfter passing through a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, concentrating the mixture and then entering a post-treatment device.

In some embodiments, the filtration unit comprises N stages of filtration assemblies, and the filtration unit discharges filtrate (a) with concentrate (B); wherein, the first stage filtering component of the filtering unit is a pipe network type reverse osmosis membrane component, the m stage filtering component of the filtering unit is a nanofiltration membrane component, and the filtrate (A) of the filtering unit and the concentrated water (B) of the reverse osmosis filtering device_ro) The water inlet of the filtering unit is formed, the concentrated water (B) of the filtering unit enters a post-treatment device, N is a natural number which is greater than or equal to two, and m is a natural number which is greater than one and less than or equal to N.

In some embodiments, the filtrate (a) of the mth stage filtration assembly_m) At least a part of the inlet water of the m +1 th stage filter assembly, and the concentrated water of the m-th stage filter assembly (B)_m) A part of the concentrate (B) constituting the filtration unit; and m is a natural number greater than one and less than N.

In some embodiments, the filtrate (A) of the Nth stage filtration assembly_N) A part of the filtrate (A) of the filtration unit and the concentrated water (B) of the reverse osmosis filtration device_ro) Constituting the inlet water of the filtration unit.

In some embodiments, a filtration unit is provided for treating concentrate (B) of a reverse osmosis filtration device_ro) The filtration unit comprises a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, and the concentrated water (B) of the reverse osmosis filtration device_ro) Concentrating the filtrate by a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, and then entering a post-treatment device; wherein the filtration unit comprises N stages of filtration components, and discharges filtrate (A) and concentrated water (B); and wherein a first stage filtering component of the filtering unit is a pipe network type reverse osmosis membrane component, an m stage filtering component of the filtering unit is a nanofiltration membrane component, and filtrate (A) of the filtering unit and concentrated water (B) of the reverse osmosis filtering device_ro) The inlet water of the filter unit is formed, and the concentrated water (B) of the filter unit enters a post-positioned positionTreatment plant, concentrate (B) of the m-1 th stage filtration module_m-1) Constitutes at least a part of the influent water of the m-th stage filtration module, the filtrate of the m-th stage filtration module (A)_m) And N is a natural number greater than or equal to two, and m is a natural number greater than one and less than or equal to N.

In some embodiments, when m equals N, the concentrate of the mth stage filter assembly (B)_m) The concentrated water (B) constituting the filtration unit enters the post-treatment device.

In some embodiments, the filtrate (A) of the second stage filtration assembly₂) A part of the filtrate (A) of the filtration unit and the concentrated water (B) of the reverse osmosis filtration device_ro) Constituting the inlet water of the filtration unit.

In some embodiments, in any one of the filtration units described above, the filtrate (a) of the pipe-grid reverse osmosis membrane module₁) And entering a reuse system.

In some embodiments, the recycling system is a reclaimed water recycling system.

In some embodiments, in any one of the filtration units described above, the filtrate (a) of the pipe-grid reverse osmosis membrane module₁) The volume ratio of the water to the inlet water of the pipe network type reverse osmosis membrane component is (70-80): 100.

In some embodiments, the filtrate (a) of the m-th stage filtration assembly_m) The volume ratio of the water to the inlet water of the m-stage filtering component is (50-80): 100.

In some embodiments, in any one of the filtration units, the filter membrane material of the nanofiltration membrane module is sulfonated polyethersulfone.

In some embodiments, the filter membrane of the nanofiltration membrane component has a pore diameter of 1-2 nm, and the cut-off molecular weight of the nanofiltration membrane component is 500-2000 daltons.

In some embodiments, in any one of the filtration units described above, the post-treatment device is an MVR evaporator.

According to another aspect of the application, a water treatment is also providedA system for treating wastewater, the water treatment system comprising: an ultrafiltration membrane filtration device, the wastewater constituting the influent to the ultrafiltration membrane filtration device, and the ultrafiltration membrane filtration device discharging the filtrate (A)_uf) And concentrated water (B)_uf) (ii) a A reverse osmosis filter device, the filtrate (A) discharged from the ultrafiltration membrane filter device_uf) Forming the feed water of the reverse osmosis filtration unit, and the reverse osmosis filtration unit discharging the filtrate (A)_ro) And concentrated water (B)_ro) (ii) a And a filter unit for treating the concentrate (B) of the reverse osmosis filter device_ro) The filtration unit comprises a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, and the concentrated water (B) of the reverse osmosis filtration device_ro) After being concentrated by a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, the mixture enters a post-treatment device.

In some embodiments, the water treatment system comprises any one of the filtration units described above.

In the present application, the concentrated water (B) to the reverse osmosis filter device is realized by the filter unit which is specially designed_ro) The experiment shows that the salt concentration of the concentrated water (B) discharged by the filter unit is obviously higher than that of the concentrated water (B) of the reverse osmosis filter device_ro) And the amount of the concentrated water (B) discharged by the filtering unit is only 10-20% of the amount of the inlet water of the filtering unit.

Therefore, this application the filtration unit can carry out efficient desalination to reverse osmosis filter equipment's dense water and produce the normal water, realizes the effect of high-efficient concentrated salinity, and then reduces the water yield of follow-up entering MVR evaporimeter remarkably. Therefore, compared with the existing treatment system shown in fig. 1, the water treatment system comprising the filtering unit can significantly reduce the energy consumption of the MVR evaporator, so that the overall treatment energy consumption is effectively reduced, and the purposes of energy conservation and emission reduction are achieved.

Drawings

FIG. 1 is a prior art conventional cotton seed printing and dyeing wastewater treatment system;

FIG. 2 is a schematic diagram of a filter unit 100 according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a filter unit 110 according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a filter unit 120 according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a filter unit 130 according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a filter unit 140 according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a water treatment system 200 according to an embodiment of the present application.

Detailed Description

Hereinafter, the technology of the present application will be described in detail with reference to specific embodiments. It should be understood that the following detailed description is only for assisting those skilled in the art in understanding the present application, and is not intended to limit the present application.

Example 1 Filter Unit 100

Referring to fig. 2, fig. 2 is a filter unit 100 according to the present embodiment. The filter unit 100 is used for treating the concentrated water B of a reverse osmosis filter device 20_ro. That is, the concentrate B of the reverse osmosis filter device 20_roAs the inlet water for the filter unit 100. The filter unit 100 includes multiple stages of filter components, that is, the filter unit 100 includes N stages of filter components, where N is a natural number greater than or equal to two. The N-stage filtering components comprise a pipe network type reverse osmosis membrane component STRO and at least one nanofiltration membrane component NF. Specifically, in the N-stage filtering components of the filtering unit 100, the first-stage filtering component of the filtering unit 100 is a pipe network type reverse osmosis membrane component, the mth-stage filtering component of the filtering unit is a nanofiltration membrane component, and m is a natural number greater than one and less than N. Typical examples of the specific structure of the filter unit 100 will be described in detail in embodiments 2 to 4 below.

As shown in fig. 2, the concentrate B of the reverse osmosis filter device 20_roAfter being concentrated by the filter unit 100, the concentrated solution enters a post-treatment device 30. That is, in the present application, the concentrate B of the reverse osmosis filtration device 20_roThe concentrated reverse osmosis membrane module STRO and the at least one nanofiltration membrane module NF pass through the pipe network type reverse osmosis membrane module STRO of the filtration unit 100, and then enter a post-treatment apparatus 30.

Specifically, as shown in fig. 2, the concentrate B of the reverse osmosis filtration device 20_roAs the inlet water of the filter unit 100 is concentrated by the filter unit 100, the filter unit 100 discharges a filtrate a and a concentrate B, wherein: a part of the filtrate A of the filtration unit and the concentrated water B of the reverse osmosis filtration device 20_roThe inlet water of the filter unit 100, the other part of the filtrate A of the filter unit and the filtrate A of the reverse osmosis filter device 20_ROEntering a reuse system 40; the concentrated water B of the filtering unit 100 enters the post-treatment device 30.

In this embodiment, the recycling system 40 can be a reclaimed water recycling system, and the post-treatment device 30 can be an MVR evaporator.

Example 2 Filter Unit 110

This embodiment is a typical structural example of the filter unit 100 described in embodiment 1 of the present application. Referring to fig. 3, fig. 3 is a filter unit 110 according to the present embodiment.

As shown in fig. 3, the filtering unit 110 is used to treat the concentrate B of the reverse osmosis filtering device 20 shown in fig. 2_roAnd, the filtering unit 110 includes a three-stage filtering assembly. Specifically, the filtering unit 110 includes: the device comprises a first-stage filtering component 111, a second-stage filtering component 112 and a third-stage filtering component 113, wherein the first-stage filtering component 111 is a pipe network type reverse osmosis membrane component, and the second-stage filtering component 112 and the third-stage filtering component 113 are nanofiltration membrane components.

Hereinafter, the filtering flow direction and setting parameters between the filtering components of each stage in the filtering unit 110 according to the embodiment will be described in detail with reference to fig. 3.

As shown in FIG. 3, the concentrate B of the reverse osmosis filter device 20 shown in FIG. 2_roAs the inlet water of the first stage filter assembly 111, filtrate A of the first stage filter assembly 111₁Enters a recycling system 40, and the concentrated water B of the first stage filter assembly 111₁As the feed to the second stage filter assembly 112. The pressure resistant strength of the first-stage filtering component 111 is 7.5MP, the pump pressure is controlled to be 6-7 MP, and the salt concentration of the inlet liquid is controlled<15g/L, and the salt concentration of the discharged concentrated solution is between 60 and 80 g/L.

As shown in fig. 3, filtrate a of the second stage filter assembly 112₂Feed water constituting the third stage filtering unit 113; concentrate B of second stage filter assembly 112₂Into a post-processing apparatus 30.

As shown in fig. 3, filtrate a of the third stage filtering assembly 113₃Concentrated water B of the reverse osmosis filtering device_roThe inlet water forming the first stage filter assembly 111; concentrated water B of the third stage filtering component 113₃Also into a post-processing apparatus 30.

The basic membrane materials of the second-stage filtering component 112 and the third-stage filtering component 113 are sulfonated polyether sulfone, and the aperture of the filtering membrane is 1-2 nm. The molecular weight cut-off of the second-stage filtering component 112 and the third-stage filtering component 113 is 500-2000 daltons, and the pump pressure is controlled to be 1-1.5 MP. Experiments show that in the embodiment, when the second-stage filtering component 112 and the third-stage filtering component 113 are used for treating high-salinity (20-100 g/L sodium sulfate) cotton printing and dyeing wastewater, more than 90% of larger-molecule substances such as dyes can be intercepted, and the intercepting effect on the concentration of sodium sulfate is 10-20 g/L.

In this embodiment, the salt (Na) is added₂SO₄) Concentrated water B with the content of 9.4g/L and the chroma of 343_roAs a processing object of the filtering unit 110. 1000m of cotton printing and dyeing wastewater discharged in the cotton printing and dyeing process³The situation of day estimates that the cotton dyeing wastewater was biochemically treated and then treated with a reverse osmosis filtration unit, wherein 70% of the cotton dyeing wastewater was converted to reusable medium water and the remaining 30% of the cotton dyeing wastewater was converted to concentrate B of the reverse osmosis filtration unit_ro. Therefore, in this embodiment, the concentrate B of the reverse osmosis filtration device_roAt a flow rate of 15m³/h(300m³Day) is the standard. The filter components of the filter unit 110 were set according to the parameters shown in Table 1 to perform the experiment of the treatment effect. The yield in table 1 is the ratio of the volume of the filtrate of a filter element to the volume of the feed water of the filter element, i.e., yield ═ V_Filtrate/V_{Inflow water}。

TABLE 1 parameters of the various filter components of the filter unit 110

As can be seen from table 1 and fig. 3, in the present embodiment, the inlet water of the filtering unit 110 is the concentrated water B of the reverse osmosis filtering device_roThe filtrate finally produced by the filtration unit 110 and available for the recycling system 40 is filtrate a of the first filtration component 111₁The concentrated water finally produced by the filtering unit 110 and entering the post-processing device 30 is the concentrated water B of the second stage filtering component 112₂And the concentrated water B of the third stage filtering component 112₃。

From this, it can be seen from Table 1 that the concentrate B in the reverse osmosis filtration apparatus as the object of treatment_roHas a flow rate of 15m³/h(300m³Day), the flow rate of the reusable filtrate discharged from the filtration unit 110 is 13.5m³H, 1.5m of concentrated water discharged³H (about 30 m)³/day)。

Therefore, when the post-processing device 30 is an MVR evaporator, the filtering unit 110 of the present embodiment can significantly reduce the amount of water evaporated by the MVR evaporator. Contrast cotton printing and dyeing wastewater 1000m³The drainage amount of/day, the filtration unit 110 described in this embodiment can realize zero discharge of cotton printing and dyeing wastewater, and the amount of water that needs to be evaporated by the MVR evaporator is only 3% of the total amount of cotton printing and dyeing wastewater, so as to realize low energy consumption.

Moreover, each stage of the filtering components of the filtering unit 110 in this embodiment is the existing filtering component, and a high-pressure pump does not need to be additionally added, so that the treatment cost of the cotton printing and dyeing wastewater is greatly reduced, and the zero emission of the low-cost cotton printing and dyeing wastewater is realized.

To further optimize the treatment effect of the filter unit 110 shown in fig. 3, salt (Na) is added₂SO₄) The amount was 9.4g/L, the color content was 343, and the flow rate was 15m³Concentrated water B of/h_roAs a processing object of the filtering unit 110, the cleaning yield of each stage of filtering components of the filtering unit 110 is further adjusted, so as to achieve the purpose of regulating and controlling the water quantity and salinity of the filtrate and the concentrated water. The relationship between the yield of each filtration module and the final filtrate from the filtration unit 110 that can be used in the recycling system 40 and the concentrate entering the post-treatment device 30 is shown in table 2.

TABLE 2 filtrate and concentrated water of the filter unit 110 corresponding to different yield rates of each stage of filter assembly

Wherein the salt discharge rate is the ratio of the salt content in the concentrated water produced by the filtering unit 110 to the salt content in the total amount of the treated water, i.e. the salt discharge rate is S_{Concentrated water}×Q_{Concentrated water}/(S_{Concentrated water Bro}×Q_{Concentrated water Bro})×100％。

S_{Concentrated water}Salinity of the concentrate produced by the filtration unit 110; s_{Concentrated water Bro}Concentrated water B as the feed water to the filter unit 110_roSalinity of (a); q_{Concentrated water}The flow rate of the concentrated water produced by the filtering unit 110; q_{Concentrated water Bro}Concentrated water B as the feed water to the filter unit 110_roThe flow rate of (c).

As can be seen from the data of tables 1 and 2, in the filter unit 110 of the present embodiment, the first stage filter assembly 111 discharges the concentrate B₁After the second stage filtering assembly 112 and the third stage filtering assembly 113 are concentrated, the concentrated water B discharged from the first stage filtering assembly 111₁In (1)More than 90% of the salt and other impurities are concentrated in the concentrated water finally produced by the filtering unit 110, and then enter the post-treatment device 30 for treatment. And filtrate A of the third stage filter assembly 113₃The salt content of the water is reduced to 30-50 g/L, and then the water is returned to the water inlet of the first-stage filtering component 111 for continuous desalination.

Thus, the circulation of the filter unit 110 according to the present embodiment can realize the circulation of the concentrate B of the reverse osmosis filter device_roAfter all treatment is finished, no wastewater is discharged from the filtering unit 110, and zero discharge of cotton printing and dyeing wastewater in the cotton dyeing process is realized.

Example 3 filtration Unit 120

This embodiment is another typical structural example of the filter unit 100 described in embodiment 1 of the present application. Referring to fig. 4, fig. 4 is a filter unit 120 according to the present embodiment.

As shown in fig. 4, the filtering unit 120 is used to treat the concentrated water B of the reverse osmosis filtering device 20 shown in fig. 2_roAnd, the filter unit 120 includes a two-stage filter assembly. Specifically, the filtering unit 120 includes: the filter comprises a first stage filtration assembly 121 and a second stage filtration assembly 122, wherein the first stage filtration assembly 121 is a pipe-network type reverse osmosis membrane assembly, and the second stage filtration assembly 122 is a nanofiltration membrane assembly.

Hereinafter, the filtering flow direction and setting parameters between the filtering components of each stage in the filtering unit 120 according to the embodiment will be described in detail with reference to fig. 4.

As shown in FIG. 4, the concentrate B of the reverse osmosis filter device 20 shown in FIG. 2_roAs the inlet water of the first stage filtration assembly 121, the filtrate a of the first stage filtration assembly 121₁Enters a recycling system 40, and the concentrated water B of the first stage filter assembly 121₁As feed to the second stage filter element 122. The pressure resistant strength of the first-stage filtering component 121 is 7.5MP, the pump pressure is controlled to be 6-7 MP, and the salt concentration of the inlet liquid is controlled<15g/L, and the salt concentration of the discharged concentrated solution is between 60 and 80 g/L.

As shown in fig. 4, filtrate a of the second stage filter assembly 122₂With the concentrated water B of the reverse osmosis filter device_roThe inlet water forming the first stage filter assembly 121; concentrate B of the second stage filter assembly 122₃Into a post-processing apparatus 30.

The basic membrane material of the second-stage filtering component 122 is sulfonated polyether sulfone, and the aperture of the filtering membrane is 1-2 nm. The molecular weight cut-off of the second-stage filtering component 122 is 500-2000 daltons, and the pump pressure is controlled to be 1-1.5 MP. Experiments show that in the embodiment, when the second-stage filtering component 122 is used for treating high-salinity (20-100 g/L sodium sulfate) cotton printing and dyeing wastewater, more than 90% of larger-molecule substances such as dyes can be intercepted, and the interception effect on the concentration of sodium sulfate is 10-20 g/L.

In this example, the same concentrated water B as in example 2 was used_roAs a processing object of the filtering unit 120. I.e. with salt (Na)₂SO₄) Concentrated water B with the content of 9.4g/L and the chroma of 343_roAs a processing object of the filtering unit 120, the cleaning yield of each stage of filtering components of the filtering unit 120 is adjusted, so as to achieve the purpose of regulating and controlling the water quantity and salinity of the filtrate and the concentrated water. The relationship between the yield of each filtration module and the final filtrate from the filtration unit 120 that can be used in the recycling system 40 and the concentrate entering the post-treatment device 30 is shown in table 3.

TABLE 3. filtrate and concentrated water of the filtering unit 120 corresponding to different production and cleaning rates of each stage of filtering component

Wherein the salt rejection rate is the ratio of the salt content in the concentrated water produced by the filtering unit 120 to the salt content in the total amount of the treated water, that is, the salt rejection rate is S_{Concentrated water}×Q_{Concentrated water}/(S_{Concentrated water Bro}×Q_{Concentrated water Bro})×100％。

S_{Concentrated water}Salinity of the concentrate produced by the filtration unit 120; s_{Concentrated water Bro}Concentrated water B as the feed water to the filter unit 120_roSalinity of (a); q_{Concentrated water}Concentrated water produced for the filtering unit 120The flow rate of (a); q_{Concentrated water Bro}Concentrated water B as the feed water to the filter unit 120_roThe flow rate of (c).

Compared with the filtering unit 110 in embodiment 2, the filtering unit 120 in this embodiment has a simpler structure and lower processing cost; however, the data in tables 2 and 3 show that the salinity (>1.0g/L) of the filtrate produced by the filtration unit 120 of this example is slightly higher than the salinity (0.6-0.9 g/L) of the filtration unit 110 of example 2, and the salt rejection rate of the filtration unit 120 of this example is also slightly lower than the filtration unit 110 of example 2.

Example 4 Filter Unit 130

This embodiment is another typical structural example of the filter unit 100 described in embodiment 1 of the present application. Referring to fig. 5, fig. 5 is a filter unit 130 according to the present embodiment.

As shown in fig. 5, the filtering unit 130 is used to treat the concentrate B of the reverse osmosis filtering device 20 shown in fig. 2_roAnd, the filtering unit 130 includes a three-stage filtering assembly. Specifically, the filtering unit 130 includes: the filter comprises a first-stage filtering component 131, a second-stage filtering component 132 and a third-stage filtering component 133, wherein the first-stage filtering component 131 is a pipe network type reverse osmosis membrane component, and the second-stage filtering component 132 and the third-stage filtering component 133 are nanofiltration membrane components.

Hereinafter, the filtering flow direction and setting parameters between the filtering components of each stage in the filtering unit 130 according to the embodiment will be described in detail with reference to fig. 5.

As shown in FIG. 5, the concentrate B of the reverse osmosis filter device 20 shown in FIG. 2_roAs the inlet water of the first stage filter assembly 131, the filtrate a of the first stage filter assembly 131₁Enters a recycling system 40, and the concentrated water B of the first stage filter assembly 131₁As part of the feed water to second stage filter element 132. The pressure resistant strength of the first-stage filtering component 131 is 7.5MP, the pump pressure is controlled to be 6-7 MP, and the salt concentration of the inlet liquid is controlled<15g/L, and the salt concentration of the discharged concentrated solution is 60-80 g/L.

As shown in fig. 5, the filtrate of the second stage filter assembly 132A₂With the concentrated water B of the reverse osmosis filter device_roThe influent water that constitutes the first stage filter assembly 131; concentrate B of second stage filter assembly 132₂Which constitutes the influent to the third stage filter assembly 133.

As shown in fig. 5, filtrate a of the third stage filter assembly 133₃Concentrated water B with the first stage filter assembly 131₁The feed water that constitutes the second stage filter element 132; the concentrated water B of the third stage filtering assembly 133₃Into a post-processing apparatus 30.

The basic membrane materials of the second-stage filtering component 132 and the third-stage filtering component 133 are sulfonated polyether sulfone, and the aperture of the filtering membrane is 1-2 nm. The molecular weight cut-off of the second-stage filtering component 132 and the molecular weight cut-off of the third-stage filtering component 133 are both 500-2000 daltons, and the pump pressure is controlled to be 1-1.5 MP. Experiments show that in the embodiment, when the second-stage filtering component 132 and the third-stage filtering component 133 are used for treating high-salinity (20-100 g/L sodium sulfate) cotton printing and dyeing wastewater, more than 90% of larger molecular substances such as dyes and the like can be intercepted, and the intercepting effect on the concentration of sodium sulfate is 10-20 g/L.

In this example, the same concentrated water B as in example 2 was used_roAs a processing object of the filtering unit 130. I.e. with salt (Na)₂SO₄) Concentrated water B with the content of 9.4g/L and the chroma of 343_roAs a processing object of the filtering unit 130, the cleaning yield of each stage of filtering components of the filtering unit 130 is adjusted, so as to achieve the purpose of regulating and controlling the water quantity and salinity of the filtrate and the concentrated water. The relationship between the yield of each stage of the filtration module and the final filtrate from the filtration unit 130 that can be used in the recycling system 40 and the concentrate entering the post-treatment device 30 is shown in table 4.

TABLE 4. different product rates of each stage of filter assembly correspond to the filtrate and concentrate of the filter unit 130

Wherein the salt discharge rate is filter sheetThe salt content in the concentrated water produced by the Yuan 130 accounts for the salt content in the total amount of the treated water, namely the salt discharge rate is S_{Concentrated water}×Q_{Concentrated water}/(S_{Concentrated water Bro}×Q_{Concentrated water Bro})×100％。

S_{Concentrated water}Salinity of the concentrate produced by the filtration unit 130; s_{Concentrated water Bro}Concentrated water B as the inlet water of the filter unit 130_roSalinity of (a); q_{Concentrated water}The flow rate of the concentrated water produced by the filtering unit 130; q_{Concentrated water Bro}Concentrated water B as the inlet water of the filter unit 130_roThe flow rate of (c).

The filtering unit 130 of this embodiment includes three filtering components as the filtering unit 110 of embodiment 2, however, the processing effect of the two components is slightly different as shown by the data in table 2 and table 4. In particular, the salinity of the filtrate produced by the filtering unit 130 of the present embodiment (b>1.3g/L) is higher than the salinity (0.6-0.9 g/L) of the filtering unit 110 in the embodiment 2, and the salt discharge rate of the filtering unit 130 in the embodiment (<87%) is lower than the salt rejection rate (> 92%) of the filter unit 110 of the embodiment 2, but the flow rate (0.7-1.2 m) of the concentrated water produced by the filter unit 130 of the embodiment³The flow rate of concentrated water produced by the filtering unit 110 in the embodiment 2 is obviously lower than that of concentrated water (1.2-2.7 m)³/h)。

Example 5 Filter Unit 140

This embodiment is another typical structural example of the filter unit 100 described in embodiment 1 of the present application. Referring to fig. 6, fig. 6 is a filter unit 140 according to the present embodiment.

As shown in fig. 6, the filtering unit 140 is used to treat the concentrate B of the reverse osmosis filtering device 20 shown in fig. 2_roAnd, the filtering unit 140 includes four stages of filtering components. Specifically, the filtering unit 140 includes: the membrane comprises a first-stage filtering component 141, a second-stage filtering component 142, a third-stage filtering component 143 and a fourth-stage filtering component 144, wherein the first-stage filtering component 141 is a pipe-network type reverse osmosis membrane component, and the second-stage filtering component 142, the third-stage filtering component 143 and the fourth-stage filtering component 144 are nanofiltration membrane components.

Hereinafter, the filtering flow direction and setting parameters between the filtering components of each stage in the filtering unit 140 according to the embodiment will be described in detail with reference to fig. 6.

As shown in FIG. 6, the concentrate B of the reverse osmosis filtration device 20 shown in FIG. 2_roAs the inlet water of the first stage filter assembly 141, the filtrate a of the first stage filter assembly 141₁Enters a recycling system 40, and the concentrated water B of the first stage filter assembly 141₁As part of the feed water to second stage filter assembly 142. The pressure resistant strength of the first-stage filtering component 141 is 7.5MP, the pump pressure is controlled to be 6-7 MP, and the salt concentration of the inlet liquid is controlled<15g/L, and the salt concentration of the discharged concentrated solution is 60-80 g/L.

As shown in fig. 6, filtrate a of the second stage filter assembly 142₂The inlet water forming the third stage filter assembly 143; the concentrated water B of the second stage filter assembly 142₂As part of the feed water to the fourth stage filter assembly 144.

As shown in fig. 6, filtrate a of the third stage filtering component 143₃With the concentrated water B of the reverse osmosis filter device_roThe inlet water forming the first stage filter assembly 141; concentrated water B of the third stage filter assembly 143₃Concentrated water B with the second stage filter assembly 142₂The inlet water of the fourth filtering component 144 is formed.

As shown in fig. 6, filtrate a of the fourth stage filter assembly 144₄Concentrated water B with the first stage filter assembly 141₁The feed water that constitutes the second stage filter assembly 142; the concentrated water B of the fourth stage filter assembly 144₄Into a post-processing apparatus 30.

The basic membrane materials of the second-stage filtering component 142, the third-stage filtering component 143 and the fourth-stage filtering component 144 are sulfonated polyether sulfone, and the aperture of the filter membrane is 1-2 nm. The molecular weight cut-off of the second-stage filtering component 142, the third-stage filtering component 143 and the fourth-stage filtering component 144 is 500-2000 daltons, and the pump pressure is controlled to be 1-1.5 MP. Experiments show that in the embodiment, when the second-stage filtering component 142, the third-stage filtering component 143 and the fourth-stage filtering component 144 are used for treating high-salinity (20-100 g/L sodium sulfate) cotton printing and dyeing wastewater, more than 90% of larger-molecule substances such as dyes can be intercepted, and the interception effect on the concentration of sodium sulfate is also 10-20 g/L.

In this example, the same concentrated water B as in example 2 was used_roAs a processing object of the filtering unit 140. I.e. with salt (Na)₂SO₄) Concentrated water B with the content of 9.4g/L and the chroma of 343_roAs the treatment object of the filtering unit 140, the cleaning rate of each stage of filtering components of the filtering unit 140 is adjusted, so as to achieve the purpose of regulating and controlling the water quantity and salinity of the filtrate and the concentrated water. The relationship between the yield of each filtration module and the final filtrate from the filtration unit 140 that can be used in the recycling system 40 and the concentrate entering the post-treatment device 30 is shown in table 5.

TABLE 5 filtrates and concentrated waters of the filtration units 140 corresponding to different product yields of each stage of filtration modules

Wherein the salt rejection rate is the ratio of the salt content in the concentrated water produced by the filtering unit 140 to the salt content in the total amount of the treated water, that is, the salt rejection rate is S_{Concentrated water}×Q_{Concentrated water}/(S_{Concentrated water Bro}×Q_{Concentrated water Bro})×100％。

S_{Concentrated water}Salinity of the concentrate produced by the filtration unit 140; s_{Concentrated water Bro}Concentrated water B as the inlet water of the filter unit 140_roSalinity of (a); q_{Concentrated water}The flow rate of the concentrated water produced by the filtering unit 140; q_{Concentrated water Bro}Concentrated water B as the inlet water of the filter unit 140_roThe flow rate of (c).

As shown by the data in Table 5, the flow rate of the concentrate produced by the filter unit 140 of this example was further reduced to about 0.8m³The salinity of the filtrate produced by the filtering unit 140 is about 1.3g/L to 1.5 g/L.

Example 6 Water treatment System 200

In this embodiment, a water treatment system 200 is also provided, as shown in fig. 7. The water treatment system 200 is used to treat wastewater, particularly cotton printing and dyeing wastewater. For example, as shown in fig. 7, the wastewater from a cotton dyeing system 300 first enters a biochemical treatment device 400 for biochemical treatment, and the treated wastewater enters the water treatment system 200 for further treatment.

As shown in fig. 7, the water treatment system 200 includes: a reverse osmosis filtration device 20, an ultrafiltration membrane filtration device 21, and the filtration unit 100 described in example 1. It will be understood by those skilled in the art that the filter unit 100 may also be the filter unit 110, the filter unit 120, the filter unit 130 or the filter unit 140 described in embodiments 2 to 5.

As shown in FIG. 7, the wastewater treated by the biochemical treatment apparatus 400 constitutes the influent water of the ultrafiltration membrane filtration apparatus 21, and the ultrafiltration membrane filtration apparatus 21 discharges the filtrate A_ufAnd concentrated water B_uf. Filtrate A discharged from the ultrafiltration membrane filtering device 21_ufConstitutes the feed water of the reverse osmosis filtration device 20, and the reverse osmosis filtration device 20 discharges the filtrate A_roAnd concentrated water B_ro. Furthermore, as described in the above examples 1 to 5, the concentrate B of the permeate filter device 20_roThe feed water constituting the filter unit 100 (or the filter unit 110, the filter unit 120, the filter unit 130, or the filter unit 140). The filtration unit 100 (or the filtration unit 110, the filtration unit 120, the filtration unit 130 or the filtration unit 140) is used for treating the concentrated water B of the reverse osmosis filtration device 20_roAfter concentration, the mixture enters a post-treatment device 30. Filtrate A of the reverse osmosis filtration device 20_roA portion of filtrate a associated with the filtration unit 100 (or filtration unit 110, filtration unit 120, filtration unit 130, or filtration unit 140) enters a recycling system 40.

This application the filtration unit can carry out efficient desalination to reverse osmosis filter equipment's dense water and handle and the output normal water, realizes the effect of high-efficient concentrated salinity, and then reduces the water yield of follow-up entering MVR evaporimeter remarkably. Therefore, compared with the existing treatment system shown in fig. 1, the water treatment system comprising the filtering unit can significantly reduce the energy consumption of the MVR evaporator, so that the overall treatment energy consumption is effectively reduced, and the purposes of energy conservation and emission reduction are achieved.

The present application has been described in relation to the above embodiments, which are only examples for implementing the present application. It must be noted that the disclosed embodiments do not limit the scope of the application. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the claims.

Claims

1. A filter unit for treating the concentrate (B) of a reverse osmosis filter unit_ro) Characterized in that the filtration unit comprises a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, and the concentrated water (B) of the reverse osmosis filtration device_ro) After being concentrated by a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, the mixture enters a post-treatment device.

2. The filtration unit according to claim 1, characterized in that it comprises N stages of filtration modules and discharges a filtrate (a) with a concentrate (B); wherein the content of the first and second substances,

the first stage of filtering component of the filtering unit is a pipe network type reverse osmosis membrane component,

the m-stage filtering component of the filtering unit is a nanofiltration membrane component,

a part of the filtrate (A) of the filtration unit and the concentrate (B) of the reverse osmosis filtration device_ro) The inlet water of the filter unit is formed,

the concentrated water (B) of the filtering unit enters a post-treatment device, and,

n is a natural number greater than or equal to two, and m is a natural number greater than one and less than or equal to N.

3. A filter unit as claimed in claim 2, characterised in that the filtrate (a) of the m-th stage filter assembly_m) Of feed water forming m +1 th filter unitAt least one part of the concentrated water (B) of the m-th stage filtering component_m) A part of the concentrate (B) constituting the filtration unit; and m is a natural number greater than one and less than N.

4. Filter unit according to claim 3, wherein the filtrate (A) of the N-th stage filter assembly_N) A part of the filtrate (A) of the filtration unit and the concentrated water (B) of the reverse osmosis filtration device_ro) Constituting the inlet water of the filtration unit.

5. Filter unit according to claim 2, wherein the concentrate (B) of the m-1 th stage filter module_m-1) At least a part of the feed water of the m-th stage filter assembly, the filtrate (A) of the m-th stage filter assembly_m) Forming at least a portion of the influent water for the m-1 or m-2 stage filtration modules.

6. Filter element according to claim 5, wherein the concentrate (B) of the m-th stage filter module is such that when m is equal to N_m) The concentrated water (B) constituting the filtration unit enters the post-treatment device.

7. Filter unit according to claim 5, wherein the filtrate (A) of the second stage filter assembly₂) A part of the filtrate (A) of the filtration unit and the concentrated water (B) of the reverse osmosis filtration device_ro) Constituting the inlet water of the filtration unit.

8. A filter unit according to any one of claims 1 to 7, wherein the filtrate (A) of the pipe-screen reverse osmosis membrane module₁) And entering a reuse system.

9. The filtration unit of claim 8, wherein the recycling system is a reclaimed water recycling system.

10. A filter unit according to any one of claims 1 to 7, which isCharacterized in that the filtrate (A) of the pipe-network reverse osmosis membrane module₁) The volume ratio of the water to the inlet water of the pipe network type reverse osmosis membrane component is (70-80): 100.

11. The filtration unit according to claim 10, wherein the filtrate (a) of the m-th stage filtration module_m) The volume ratio of the water to the inlet water of the m-stage filtering component is (50-80): 100.

12. The filtration unit of any one of claims 1 to 7, wherein the filter membrane material of the nanofiltration membrane module is sulfonated polyethersulfone.

13. The filtration unit of claim 11, wherein the nanofiltration membrane module has a membrane pore size of 1-2 nm and a molecular weight cut-off of 500-2000 daltons.

14. A filter unit as claimed in any one of claims 1 to 7, wherein the post-treatment device is an MVR evaporator.

15. A water treatment system for treating wastewater, the water treatment system comprising:

an ultrafiltration membrane filtration device, the wastewater constituting the influent to the ultrafiltration membrane filtration device, and the ultrafiltration membrane filtration device discharging the filtrate (A)_uf) And concentrated water (B)_uf)；

A reverse osmosis filter device, the filtrate (A) of the ultrafiltration membrane filter device_uf) Forming the feed water of the reverse osmosis filtration device, and discharging the filtrate (A)_ro) And concentrated water (B)_ro) (ii) a And the number of the first and second groups,

a filter unit for treating the concentrate (B) of the reverse osmosis filter device_ro) The filtration unit comprises a pipe network type reverse osmosis membrane component and at least one nanofiltration membrane component, and the concentrated water (B) of the reverse osmosis filtration device_ro) Passing through a pipe network type reverse osmosis membrane module andand after being concentrated, the nanofiltration membrane component enters a post-treatment device.