KR101909277B1 - Drainage treatment system for membrane filtration and Drainage treatment method using the same - Google Patents

Abstract

The membrane filtration effluent treatment system according to the present invention comprises a reforming means for receiving concentrated water discharged from a final separation membrane in at least one separation membrane process and modifying physical properties of the suspended material through oxidation treatment using ozone (O ₃ ) A flocculation means for injecting an environmentally friendly flocculant into the treated water through the reforming means to improve flocculation and flotation efficiency; and a fine bubble float separation means for separating suspended matters by spraying fine bubbles into the treated water passing through the flocculation means, Wherein the flotage separation means comprises a flotation separation tank, a pressure chamber in which a part of the treated water is received, a compressor for pressurizing and supplying gas to the treatment water contained in the pressurization chamber, And a nozzle for spraying the treated water in which gas is dissolved to generate minute bubbles, Number is re-transferred to the raw water tank, the separated suspended matter is discharged to the outside. According to the present invention, Near ZLD (Zero Liquid Discharge) can be achieved by achieving a total process recovery rate of 99.5% to 99.9%, and floatation efficiency is improved by performing physical property modification of the membrane concentrated water with ozone (O ₃ ) by reducing the processing sunae suspected substance causing Alzheimer's Al ^{3 +} concentration through eco coagulant injection has the advantage of being able to resolve the risk of health problems at the same time.

Description

TECHNICAL FIELD The present invention relates to a membrane filtration effluent treatment system and a membrane filtration effluent treatment method using the membrane filtration effluent treatment system.

The present invention relates to a membrane filtration effluent treatment system capable of reducing the amount of effluent generated in a purification process using a separation membrane, and a membrane filtration effluent treatment method using the membrane filtration effluent treatment system.

Typical water treatment processes consist of intake and flooding, mixing and coagulation, sedimentation, filtration and disinfection.

During the water intake and the water intake process, water is drawn from a river or a dam and is accommodated in the water tank to stabilize the flow of water.

The flow-stabilized water in the head is transferred to the mixed paper.

In the mixed paper, a coagulant is added and mixed with water. Here, the coagulant is mainly composed of an aluminum-based coagulant. After the coagulant is flocculated, fine droplets in the water are agglomerated to form a lump so that precipitation can be performed well.

The water mixed with the flocculant in the admixture is conveyed to the settling basin.

In the settling basin, floating matters in the water are precipitated while the water stays for a predetermined time. The suspended matters as described above are discharged to the sludge and the water on the upper side of the sedimentation tank is transferred to the filter paper.

In the filter paper, fine particles which have not been removed from the settling paper are removed by passing through the sand layer, and the water passed through the filter paper is supplied to the tap water through the disinfection process.

On the other hand, in the general water treatment process, the discharge water such as sedimentation sludge (sludge) and the backwash water discharged from the sand filtration is generated at 3 to 15% of the purified water level, and the sedimentation property is poor, .

In addition, in the general purification process, there is a problem that it is difficult to secure the final quality of the treated water according to the fluctuation of the influent source, and the membrane separation process is attracting attention.

The membrane filtration process has advantages such as ensuring stable water quality and reducing the generation of drainage water during the year.

However, in the case of single-stage membrane filtration, 1 to 5% of concentrate concentrate is produced per unit volume of water, so additional alternative is needed.

On the other hand, the effluent discharged from the membrane filtration process is difficult to be treated in a gravity-type concentrator of existing water purification facilities due to the difficulty of precipitation treatment due to the large repulsive force between the particles as the effluent discharged from the sedimentation or filter paper.

In addition, in the water purification plant according to the prior art, aluminum-based inorganic flocculants (PAC, Alum, etc.) are introduced as described above. In the case of such inorganic flocculants, health problems such as dementia due to Al ^{3 +} Have problems.

It is an object of the present invention to provide a membrane filtration effluent treatment method capable of minimizing the generation of effluent in a separation membrane purification process by using a reforming of separation membrane effluent and micro-bubble pressurization separation.

It is another object of the present invention to provide a membrane filtration effluent treatment system capable of minimizing the generation of effluent water by using the membrane filtration effluent treatment method as described above.

The membrane filtration effluent treatment system according to the present invention receives concentrated water discharged from the final separation membrane in one or more separation membrane processes and reforms the properties of suspended solids (SS) through an oxidation process using ozone (O ₃ ) A coagulation means for injecting an environmentally friendly coagulant into the treated water through the reforming means to improve flocculation and floatation efficiency; and a means for separating the suspended material (SS) by spraying minute bubbles into the treated water passed through the coagulation means Wherein the floating separating means comprises a floating separating tank, a pressurizing chamber in which a part of the treated water is accommodated, a compressor for pressurizing and supplying gas to the treated water accommodated in the pressurizing chamber, And a nozzle for spraying the treated water dissolved in the gas inside the pressurizing chamber to generate minute bubbles, The material to be treated separately from the (SS) is re-transferred to the raw water tank, the separated suspended solids (SS) is characterized by being discharged to the outside.

The environmentally friendly coagulant is added at an injection concentration of 5 to 30 mg / L.

And the pressure of the pressure chamber is 2 to 5 kgf / cm 2.

Wherein the fine bubbles having a diameter ranging from 20 to 70 mu m are variably injected in the nozzle according to the pressure of the pressurizing chamber.

According to another aspect of the present invention, there is provided a membrane filtration effluent treatment method comprising the steps of introducing concentrated water discharged from a final separation membrane in at least one separation membrane process into a reforming means, supplying ozone (O ₃ ) to the concentrated water flowing in the reforming means Modifying the physical properties of suspended solids (SS), introducing an eco-cohesive agent by means of coagulation means and coagulating the suspended solids (SS), treating the coagulated material Separating suspended solids (SS) by injecting fine bubbles into the raw water tank, separating the suspended solids (SS), transferring the treated water through the fine bubble phase separation means to the raw water tank, and discharging the final concentrated sludge separated by the fine bubble phase separation means And the eco-coagulant injected in the step of flocculating the suspended solids SS is injected at an injection concentration of 5 to 30 mg / L. The.

The environmentally friendly coagulant added in the step of flocculating the suspended solids SS is characterized in that it comprises at least one of polyglutamine, amine and chitosan as main components.

In the step of spraying the minute bubbles and separating the suspended solids SS, the pressure of the pressurized chamber is maintained in the range of 2 to 5 kgf / cm 2, and the diameter of the minute bubbles is in the range of 20 to 70 μm.

According to the present invention, the floatation efficiency is improved by modifying the physical properties of the membrane-concentrated water with ozone (O ₃ ) in order to solve the problem of poor flocculation property of the separation membrane effluent.

In addition, by conventional inorganic flocculant (PAC, Alum, and so on) instead of improving coagulation efficiency through eco coagulant injection of low aluminum component, as well as reduce process water in Alzheimer induced suspected substance, Al ^{3 +} concentration to address the risk of health problems at the same time . In addition, according to the present invention, when the eco-friendly flocculant is added, the flotation rate is drastically improved as compared with the prior art in which the aluminum flocculant is added. As a result, .

Further, in the present invention, after the suspended solid material (SS) is separated through the fine bubble phase separation means, the treated water is transported to the raw water tank, thereby minimizing the generation of drainage water, thereby improving the overall process recovery rate.

In other words, when the effluent treatment according to the existing immersion method is performed in a small and medium scale water treatment plant having a daily treatment capacity of 50,000 tons (t) or less, discharge of less than 7500 tons (t) per day occurs, 2500 tonnes per day (t) per day, and 250 tonnes per day (t) per day even if a two-stage filter membrane is used.

On the other hand, in the small- and medium-sized water purification plants to which the present invention is applied, only the discharge of less than 50 tons (t) per day occurs, thereby enabling the implementation of Near ZLD (Zero Liquid Discharge) by achieving the total process recovery rate of 99.9%. As a result, not only the cost of effluent treatment, but also effluent effluent treatment is improved, thereby improving the treatment capacity of the water treatment plant.

1 schematically illustrates the structure of a membrane filtration effluent treatment system according to the present invention;
2 is a view illustrating a process of discharging wastewater according to a membrane filtration wastewater treatment method according to the present invention.
3 is a view showing a suspended solids (SS) profile according to whether or not ozone (O ₃ ) treatment is performed.
4 is a view showing a treated water turbidity (NTU) profile according to whether or not ozone (O ₃ ) treatment is performed.
FIG. 5 is a graph showing a change in sludge interface height over time with or without ozone (O ₃ ) treatment. FIG.
Figure 6 shows a treated water suspended solids (SS) profile according to coagulant.
Figure 7 shows the treated water turbidity (NTU) profile according to agglomerates.
8 is a graph showing the change in sludge interface height with time according to the flocculant.
9 is a view for showing the amount of treated water and the amount of effluent generated in a general two-stage filtration membrane process.
10 is a view showing the amount of treated water and discharged water generated by the membrane filtration effluent treatment method according to the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. It is to be understood, however, that the spirit of the invention is not limited to the embodiments shown and that those skilled in the art, upon reading and understanding the spirit of the invention, may easily suggest other embodiments within the scope of the same concept.

FIG. 1 is a view schematically showing the structure of a membrane filtration effluent treatment system according to the present invention, and FIG. 2 is a view showing a process of effluent treatment according to a membrane filtration effluent treatment method according to the present invention .

Referring to these figures, the membrane filtration effluent treatment system according to the present invention is configured to perform surface modification of suspended solids, coagulation of the modified suspended solids, and floatation separation of the coagulated suspended solids.

In detail, the membrane filtration effluent treatment system according to the present invention comprises a reforming means for receiving the concentrated water discharged from the final separation membrane in at least one separation membrane process and modifying physical properties of suspended solids (SS) (200).

The reforming means 200 includes a concentration tank 220 for storing concentrated water for reducing the organic matter content in the concentrated water discharged from the final separation membrane and an ozone generator 220 for supplying ozone (O ₃ ) to the concentration tank 220. (240).

The treated water passing through the reforming means 200 is transferred to the flocculating means 400 for injecting the environmentally friendly flocculant.

The flocculating means 400 may further include an agitator 420 for flocculating the suspended solids SS by injecting an environmentally friendly flocculant into the treated water passing through the reforming means 200.

The environmentally friendly coagulant is selected in consideration of the aluminum content and the human body and the environmental hazard. In this embodiment, the coagulant is a coagulant mainly composed of at least one of polyglutamine, amine, organic acid mixture, and chitosan Is applied.

In detail, polyglutamine is a kind of Bacillus subtilis, a natto bacterium extract, which is harmless to the human body and biodegradable.

Amine based organic coagulant is a strong cationic Epi-Amine polymer with little change in charge density due to pH change and improves the cohesion by neutralizing the surface charge of suspended solids (SS).

On the other hand, when the amount of the environmentally-friendly coagulant is less than 5 mg / L, flocculation efficiency is not improved because of flocculation, and when the amount exceeds 30 mg / L, And the floating efficiency is reduced.

Accordingly, in the present invention, the above-mentioned eco-coagulant having the main component is injected at an injection concentration of 5 to 30 mg / L for floatation efficiency.

The treated water passing through the flocculating means 400 is sent to the fine bubble phase separating means 600 for separating the suspended solids SS by spraying the fine bubbles.

The fine bubble phase separation means 600 includes a floatation separation tank 620 in which the treatment water is passed through the flocculation means 400 and a pressurization chamber 660 in which a part of the treated water accommodated in the floatation separation tank 620 is accommodated A compressor 680 for pressurizing and supplying gas to the processing water accommodated in the pressurizing chamber 660 and a nozzle 640 provided at one side of the floating separation tank 620 to generate fine bubbles .

The floating separation tank 620 is connected to the pressurizing chamber 660 through a pipe and a circulation pump P so that a predetermined amount of process water can be supplied to the pressure chamber 660.

The compressor 680 is connected to one side of the pressurizing chamber 660, and a high-pressure gas is supplied to the process water accommodated in the pressurizing chamber 660.

The nozzle 640 injects high-pressure treated water supplied through the pressurizing chamber 660 to generate micro-bubbles having an average diameter of 50 μm. As a result, The material (SS) is separated.

On the other hand, when the size of the minute bubbles generated from the nozzle 640 is less than 20 μm, the residence time of the minute bubbles becomes long and the floatation efficiency is reduced, and the construction ratio for the precise nozzle 640 is increased . If the size of the fine bubbles exceeds 70 탆, the floatation rate is fast but the flocculation between the particles is poor and the floatation efficiency is decreased.

Accordingly, in the present invention, the fine bubbles generated from the nozzle 640 are formed in a range of 20 to 70 μm, and the pressure of the pressurizing chamber 660 is controlled.

In detail, when the pressure of the pressurizing chamber 660 is less than 2 kgf / cm 2, fine bubbles can not be smoothly generated through the nozzle 640.

If it exceeds 5 kgf / cm 2, the average particle size decreases. In this case, the retention time of the bubbles is increased to decrease the floatation efficiency.

Accordingly, in the present invention, the pressure of the pressurizing chamber 660 is controlled in the range of 2 to 5 kgf / cm2.

A pressure gauge 630 is additionally provided between the pressure chamber 660 and the nozzle 640 to control the compressor 680 so that the discharge pressure can be maintained at a constant level.

Meanwhile, the suspended solids SS separated in the floatation separation tank 620 are separately treated as drain water, and the treated water in which the suspended solids S are separated is again received in the separation membrane raw water tank.

Hereinafter, a membrane filtration effluent treatment method using membrane filtration effluent treatment system having the above-described structure will be described.

First, in the membrane filtration effluent treatment method according to the present invention, the step (S100) of introducing the concentrated water discharged from the final separation membrane into the reforming means 200 in at least one separation membrane process is performed.

In the step S100, concentrated water having a high organic matter content during the multi-stage filtration is accommodated in the concentration tank 220 of the reforming means 200. [

When the concentrated water flows into the concentration tank 220 as described above, the reforming means 200 supplies ozone (O ₃ ) to the concentrated water introduced by using the ozone generator 240 so that the properties of the suspended solids (SS) (S200) is performed.

The chemical oxygen demand (COD), suspended solids concentration (SS) and turbidity (NTU) are reduced when the ozone (O ₃ ) is supplied and the physical properties of the suspended solids (SS) are modified. 1].

SS (mg / L) Turbidity (NTU) COD (mg / L) Two-stage drainage 260 145 53.66 Ozone-treated water 210 106.6 33.55

The treated water containing the suspended material SS having the modified physical properties through the step S200 is transferred to the flocculating means 400 and the flocculant SS is flocculated in the flocculating means 400, (S300) is performed.

In the step S300, an environmentally-friendly coagulant containing no aluminum or a metal series is administered. As described above, the polyglu- tamine, the amine, the chitosan, Improves flocculation efficiency while solving environmental hazard.

After the environmentally-friendly coagulant is administered, the stirring process can be performed using the stirrer 420 for a predetermined period of time. In the treated water into which the environmentally-friendly coagulant is added, the adsorption force between the fine particles is increased by charge neutralization of the suspended material, Coagulation phenomenon occurs.

In step S300, the treated water is sent to the fine bubble phase separating means 600. In the fine bubble phase separating means 600, fine bubbles are injected into the treated water passing through the coagulating means, (S400) is performed.

In step S400, the high-pressure gas is melted in the pressurizing chamber 660 containing the treated water in the floatation separating tank 620 using the compressor 680, and the treated water in which the gas is melted is stored in the floating separator 620 The microbubbles having an average diameter of 50 mu m are injected through the nozzle 640 provided on one side of the nozzle 640 to separate the suspended solids SS and the treated water.

Here, the nozzle 640 may be positioned at the bottom of the floating separation tank 620 to allow for omnidirectional spraying, and a plurality of nozzles 640 may be provided depending on the processing capacity.

If the suspended solids SS is separated from the treated water in the floatation separation tank 620 through the step S400 as described above, the step S500 of transferring the treated water separated from the suspended solids SS to the raw water tank S500, The final concentrated sludge collected on the upper side of the bath 620, that is, the suspended material SS, is discharged to the drain water through the external discharge path (S600).

That is, in the present invention, most of the treated water is returned to the raw water tank through the step S500, and only a small amount of discharged water is discharged to the outside, thereby minimizing the generation of discharged water.

On the other hand, in Figure 3 in ozone (O ₃₎ for treated water suspended solids (SS) it is shown a view showing a profile, to be treated according to whether there ozone Fig 4 (O ₃₎ treatment Turbidity (NTU) profile according to process Status FIG. 5 is a view showing a change in sludge interface height according to time according to whether or not ozone (O ₃ ) treatment is performed.

Referring to these figures, it can be seen that the flotation efficiency improves when the effluent water modification is performed through the membrane filtration effluent treatment system according to the present invention.

That is, when the ozone (O ₃ ) treatment is performed through the reforming means 200, the SS profile and turbidity are low when the ozone (O ₃ ) treatment is not performed, As well.

FIG. 6 is a graph showing the SS profile of the treated water according to the coagulant, and FIG. 7 is a graph showing the treated water turbidity (NTU) profile according to the coagulant. The sludge interface height changes with time.

Referring to these drawings, it has been found that the use of an amine coagulant, which is an embodiment of an environmentally friendly coagulant, through the membrane filtration effluent treatment system according to the present invention improves the quality of treated water and improves the floatation separation rate.

In other words, when the amine-based flocculant is used, as shown in FIG. 6, the SS profile is significantly lower than that of the flocculent and PAC (aluminum-based) flocculant, and the turbidity is also significantly lower It was shown.

In addition, the flotation rate was significantly improved immediately after the addition, compared to the no flocculation and PAC (aluminum series) coagulant.

FIG. 9 is a view showing the amount of treated water and discharged water generated in the general two-stage filtration membrane process, and FIG. 10 is a view showing the amount of treated water and discharged water generated by the membrane filtration effluent treatment method according to the present invention, .

Referring to these drawings, the membrane filtration effluent treatment system according to the present invention can be compared with the case where the membrane filtration water treatment system is not applied to the bi-membrane process. In the bi-membrane process where the present invention is not applied, 5% of the waste water was generated from the raw water, and the treated water was treated in the second membrane (20), and the final recovery rate of the raw water was 99.5%.

(Ton) of the effluent discharged from the first membrane 10 flows into the second membrane 20 and the final effluent reaches 500 tons (t) ) Can be calculated.

On the other hand, when the present invention is applied, 5000 tons (t) of discharged water discharged from the one-piece membrane 10 flows into the two-layer membrane 20 to generate 500 tons (t) 500 tons (t) of the effluent flows into the membrane filtration effluent treatment system 100 according to the present invention, resulting in 100 tons (t) of the final effluent, resulting in a 5-fold saving effect. In addition, the amount of such waste water savings increases in proportion to the treatment capacity of the raw water.

100 membrane filtration effluent treatment system 200 reforming means
220 ........ Enrichment tank 240 ........ Ozone generator
400 ........ Agglomeration means 420 ........ Agitator
600 ......... minute bubble floating separating means 620 ........ separating tank
630 ........ pressure gauge 640 ........ nozzle
660 ........ Pressurizing chamber 680 ........ Compressor

Claims (7)

A reforming means for modifying physical properties of suspended solids (SS) through oxidation treatment using ozone (O ₃ ) to receive concentrated water discharged from the final separation membrane in at least one separation membrane process and to improve floatation efficiency;
Agglomeration means for injecting an environmentally friendly flocculant into the treated water through the reforming means to improve flocculation and flotation efficiency;
The environment-
An amine system as a main component;
And fine bubble phase separation means for separating the suspended solids (SS) by spraying the fine bubbles to the treated water having passed through the modifying means and the aggregating means,
Wherein said floating-
A floating separation tank,
A pressurizing chamber in which a part of the treated water is received,
A compressor for pressurizing and supplying the processing water stored in the pressure chamber; And
And a nozzle provided at one side of the floating separation tank for spraying treated water in which gas is dissolved in the pressure chamber to generate fine bubbles
The treated water separated from the suspended solids SS is re-transferred to the raw water tank, the separated suspended solids SS are discharged to the outside,
The environment-
Is injected at an injection concentration of 5 to 30 mg / L,
Wherein the pressure of the pressurization chamber is 2 to 5 kgf / cm < 2 >.
delete delete delete A membrane filtration effluent treatment method using the membrane filtration effluent treatment system of claim 1,
Introducing the concentrated water discharged from the final separation membrane into the reforming means in at least one separation membrane process;
Modifying physical properties of suspended solids (SS) by supplying ozone (O ₃ ) to the concentrated water introduced into the reforming means;
Adding an environmentally-friendly coagulant to coagulate the suspended material (SS) using the coagulation means;
Separating the suspended solids (SS) by spraying fine bubbles into the treated water passed through the coagulating means through the fine bubble float separating means;
Transferring the treated water through the fine bubble floating separation means to the raw water tank; And
Discharging the final concentrated sludge separated in the fine bubble floating separation means,
The eco-friendly coagulant added in the step of flocculating the suspended solids (SS)
Lt; RTI ID = 0.0 > mg / L. ≪ / RTI >
delete delete

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