KR20120001845A - Apparatus for treating water - Google Patents

Abstract

PURPOSE: A water treating apparatus is provided to minimize unnecessary energy consumption in a water treating process by elastically selecting a fiber filter and a membrane filter corresponding to the turbidity of water. CONSTITUTION: A line mixer(110) rapidly mixes inorganic coagulant(111) and raw water. A coagulating bath(120) is serially connected with the line mixer and grows the size of coagulated floc. A fiber filter(130) is serially connected with the coagulating bath and directly filters coagulated water through a filtering media based on fiber media. A membrane filter(140) is serially connected with the fiber filter and re-filters the filtered water through a membrane. The membrane filter includes a microfiltration membrane or an ultra-filtration membrane.

Description

Apparatus for treating water

The present invention relates to a water treatment apparatus using a fiber filter and membrane filter technology, and more particularly, most of the turbidity-causing substances such as suspended solids and colloids contained in raw water, odors, tastes, etc. Water treatment device that can be used as a pretreatment for advanced treatment such as reverse osmosis membrane filtration by filtering out some of the dissolved substances, microorganisms such as algae, protozoa, bacteria and viruses and impurities such as dissolved inorganic salts that cause It is about.

In general, it is a technique for removing impurities such as suspended substances such as drift water, submerged water, ground water, sea water, sewage and waste water, turbidity substances such as colloids, and microorganisms of relatively large size such as algae and protozoa. Sand filtration after chemical flocculation, mechanical filtration after chemical flocculation, and direct mechanical filtration treatment by omission of a precipitation tank after chemical flocculation.

First, after the chemical flocculation sedimentation, sand filtration treatment technology uses a chemical flocculant, and aggregates impurities by such chemical flocculant into flocs and flows into the precipitation tank. After the chemical flocculation sedimentation, the sand filtration treatment method is a method of first removing the floc from the sedimentation tank and then removing the residual turbidity-causing substances by entering the sand filter at the rear stage. The advantage of this technology is that it is a process that is familiar to the general driver by textbook method, and since the operating conditions are most established due to changes in the surrounding environment such as raw water quality so far, the cause of the malfunction and the measures to eliminate the cause are generalized. Is that it is. However, because the size is very large compared to the processing capacity, it takes up a lot of installation site and high construction cost, and because the size of the flocculated floc needs to be large in order to precipitate most flocculated flocs, Will cause an increase. In addition, there is a limit that the water quality of the treated filtrate is not satisfactory.

Next, in the case of the mechanical filtration treatment technology after the chemical flocculation sedimentation, the process of chemical coagulation and precipitation from the raw water is the same as the above-described sand filtration treatment technique after the chemical flocculation sedimentation, but the mechanical size is generally about 1/4 of that of the sand filtration. The use of a filter can reduce the overall size, but the sedimentation tank, which occupies most of the required site, is still needed, so the site for building the entire process is very large. On the other hand, in the removal performance of the turbidity-causing substances, sand filter is generally about 50%, while in the case of general mechanical filter other than membrane filtration is more than 85% than sand filter.

Subsequently, in the case of the direct mechanical filtration treatment technique by omitting the settling tank after the chemical coagulation, from the raw water to the chemical coagulation, it is the same as the two methods described above. The difference is that. Therefore, the site required for the construction of the facility is reduced to 1/10 to 1/50 than the existing treatment process, which can greatly reduce the construction cost, and it is not necessary to settle the chemical flocculation flocs, so even if the size is smaller than that of the sedimentation tank. In general, the amount of flocculant used can be reduced. In addition, the coagulation aging time is also required 20-40 minutes when using a conventional sedimentation tank, but in the case of a mechanical filter 2 to 3 minutes is sufficient, the stirring power is reduced as the volume of the coagulation aging tank is reduced, there is also a reduction in operating costs. However, the first stage treatment of the mechanical filter has a problem that the treated water quality is about 1 NTU when high turbidity raw water of several tens of NTU (Nepthelometric Turbidity Unit) is introduced, far exceeding 0.5 NTU, which is a general standard of drinking water quality. When using a high concentration of inorganic coagulant to improve the clogging of the filter pores, there is a problem that the amount of backwash due to frequent backwashing increases significantly. In addition, when only the membrane (Membrane) process is applied, the turbidity of the incoming raw water is limited to less than 10 NTU.

On the other hand, when using a microfiltration membrane or an ultrafiltration membrane of 1.0 μm or less, which is not a general mechanical filter, has excellent turbidity removal efficiency close to 100%, and an immersion type separation membrane can be operated for high turbidity influent. However, in general, the filtration linear velocity is 1.0 m / day, which is 1/50 to 1/100 of the fiber filtration device, and as the size increases, the construction cost is not less than six times higher than that of the mechanical filter, and it is also used to reduce membrane contamination. The use of cleaning air and backwashing water is excessive, which is why operating costs are generally three times higher. This drawback is a common solution to remove turbidity-causing substances contained in raw water by using the above-mentioned pretreatment device before membrane filtration. Even though the best existing pretreatment device is used in one stage, 10 NTU When the above raw water flows in, it is known that the filtration linear velocity does not exceed 1.5 m / day.

In conclusion, according to the prior art as described above, by removing the turbidity-causing substances, which is the first step of the contaminant removal process included in the raw water, the required size of the subsequent high-treatment process is excessively increased to increase the construction cost and operation cost. This resulted in an increase in the cost of producing and reusing water.

The present invention was created in order to solve the above problems, while maintaining the turbidity of the treated water below the reference value, while significantly reducing the construction cost and operating cost of expensive subsequent processes, ultimately reduce the cost of production water It is an object of the present invention to provide a water treatment apparatus that can greatly reduce the cost.

According to the present invention for achieving the above object, a line mixer for rapidly mixing the raw water of the treatment target to which the inorganic coagulant is added; An agglomeration tank connected in series with the line mixer and growing raw water mixed with the inorganic coagulant to grow the size of the flocculated floc; A fiber filter connected in series with the agglomeration tank and directly filtering the agglomerated water flowing through the filter layer made of a fiber filter; And a membrane filter connected in series with the fiber filter and filtering the incoming filtrate through a membrane.

The water treatment apparatus includes: a first bypass line bypassing the fiber filter and directly connecting an outlet of the coagulation tank and an inlet of the membrane filter; A second bypass line bypassing the membrane filter and directly connecting the outlet of the fiber filter and the outlet of the membrane filter; A first switching valve installed at a branch point of the first bypass line branching from the outlet of the flocculation tank and switching the flow path so that the introduced flocculation water flows only in one direction selected from the fiber filter direction and the first bypass line direction; And a second switch installed at a branch point of the second bypass line branching from the outlet of the fiber filter, and switching the flow path so that the introduced filtration water flows only in one direction selected from the membrane filter direction and the second bypass line direction. A valve may be further provided.

In the case where the turbidity of the raw water flowing into the line mixer is 5 NTU or more, the first and second switching valves are controlled to be switched so that both the first bypass line and the second bypass line are blocked. When the turbidity of the raw water flowing into the line mixer is heavy water of 1 NTU or more and less than 5 NTU, the first and second switching valves are switched and controlled to block the first bypass line and bypass the membrane filter. 2 bypass line is open, when the turbidity of the raw water flowing into the line mixer is less than 1 NTU, the first bypass line to bypass the fiber filter by switching the first and second switching valves, It is preferable to open and to block the second bypass line.

In addition, the water treatment device, turbidity detection sensor for detecting the turbidity of the raw water flowing into the line mixer; And in response to the turbidity of the raw water detected by the turbidity detection sensor, the first and second switching valves may further include a valve control unit for adjusting to switch.

Furthermore, the membrane filter may include an MF membrane (Micro Filtration Membrane) or an UF membrane (Ultra-Filtration Membrane).

According to the water treatment apparatus according to the present invention has the following effects.

First, since the fiber filter and the membrane filter can be flexibly selected and applied according to the degree of turbidity of raw water, it is possible to maximize energy efficiency by minimizing waste of unnecessary energy during water treatment.

Second, because the raw water of high turbidity uses a fiber filter instead of a sand filter, it can reduce the required area and operating power cost of the equipment for filtration, and can remove most of the turbidity-causing substances in advance, so that the membrane is a subsequent process. Membrane permeation flow rate of the filtration process can be significantly increased compared to the existing pretreatment system, thereby significantly reducing the construction cost and operating cost of the membrane filtration process.

Third, the filtered water treated by the water treatment device according to the present invention is used according to its use, or by removing the dissolved salts by treating a subsequent process such as reverse osmosis membrane, drinking water as well as seawater desalination, river maintenance water, agriculture and It can be reused as industrial water.

1 is a schematic block diagram of a water treatment apparatus according to an embodiment of the present invention;
FIG. 2 is a block diagram for explaining a water treatment process by the water treatment apparatus shown in FIG. 1 when raw water having a heavy turbidity is introduced; FIG.
3 is a block diagram for explaining a water treatment process by the water treatment apparatus shown in FIG. 1 when raw water of low turbidity is introduced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

Referring to FIG. 1, the water treatment device 100 according to an embodiment of the present invention includes a line mixer 110, a coagulation tank 120, a fiber filter 130, and a membrane filter 140.

The raw water to be treated is introduced into the line mixer 110, before the inorganic coagulant 111 is added. The line mixer 110 rapidly mixes the raw water into which the inorganic coagulant 111 is introduced. On the other hand, the raw water flowing in is not shown in the drawing, it is preferable that the foreign matter, such as a floating material having a relatively large size by the screen forming a fine net of about 1 mm is filtered in the state. In addition, the purpose of using the inorganic coagulant 111 is to facilitate the removal of contaminants such as suspended solids including algae, polymers, and the like, and the colloidal turbidity causing substances. However, the use of such an inorganic coagulant may increase the operating cost due to the increase of the cost and the amount of sludge generated, so it is desirable to properly control the use and the amount of use according to the quality of raw water. The inorganic coagulant 111 may be a general poly aluminum chloride (PAC). Depending on the amount of the inorganic coagulant 111 is administered, turbidity and removal of suspended solids in raw water may be changed.

The coagulation tank 120 is connected in series with the line mixer 110, it may be provided in the form having a constant volume. The agglomeration tank 120 grows the size of the flocculated floc by maturing the raw water mixed with the inorganic coagulant 111.

The fiber filter 130 is connected in series with the coagulation tank 120. And the inflow of agglomerated water is directly filtered through a filter layer made of fibrous media. The fiber filter 130 may be supplied to the membrane filter 140 to be described later to remove most of the turbidity-inducing material from the coagulated mature raw water.

The membrane filter 140 is connected in series with the fiber filter 130, and the filtered filtrate is passed again through the membrane (Membrane). The purpose of the membrane filter 140 is to filter the turbidity-causing substances contained in the raw water, similarly to the fiber filter 130, and more particularly, the primary filter is filtered in the fiber filter 130 of the turbidity-causing substances It is to filter the secondary amount of the microparticles of turbidity at a lower concentration. As the membrane filter 140, an MF membrane (Micro Filtration Membrane) or an UF membrane (Ultra-Filtration Membrane) may be used. However, since the description of the membrane itself corresponds to the known art, a detailed description thereof will be omitted.

On the other hand, depending on the requirements for the quality of the filtered treated water, in order to further remove the traces of turbidity causing substances remaining in the treated water passed through the membrane filter 140, precision or ultrafiltration or dissolved in a subsequent process It can be used by connecting a high filtration device 200, such as reverse osmosis membrane filter to remove even inorganic salts. In this case, the water treatment device 100 according to the embodiment of the present invention serves as a pretreatment device of the high filtration device 200.

In the embodiment of the present invention as described above, the water treatment device 100 further includes a first and second bypass lines 150 and 160, and first and second switching valves 170 and 180. can do.

The first bypass line 150 bypasses the fiber filter 130 and has a flow path directly connecting the outlet of the coagulation tank 120 and the inlet of the membrane filter 140. In addition, the second bypass line 160 bypasses the membrane filter 140 and has a flow path directly connecting the outlet of the fiber filter 130 and the outlet of the membrane filter 140. The operation of the first and second bypass lines 150 and 160 will be described later.

The first switching valve 170 is installed at the branch point of the first bypass line 150 branching from the outlet of the flocculation tank 120, the introduced flocculation water is in the direction of the fiber filter 130 and the first bypass The flow path is switched to flow in only one selected direction of the line 150 direction. In addition, the second switching valve 180 is installed at the branch point of the second bypass line 160 branched from the outlet of the fiber filter 130, the introduced filtration water in the direction of the membrane filter 140 and the second The flow path is switched to flow only in one selected direction from the bypass line 160 direction. The first and second switching valves 170 and 180 are a three-port valve having one inlet and two outlets as a flow path switching valve, and are automatically operated as well as electronically controlled. It may be any, and embodiments of various shapes and functions are possible. The operation of the first and second switching valves 170 and 180 will also be described later.

On the other hand, irrespective of the turbidity of the incoming raw water, uniformly applying all of the fiber filter 130 and the membrane filter 140 as described above may be disadvantageous in terms of energy efficiency. That is, when raw water with low turbidity flows in, it is because treated water of desired turbidity can be obtained without using the fiber filter 130 or the membrane filter 140.

Hereinafter, in response to the turbidity of the incoming raw water, the operation of the water treatment device 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, when the turbidity of the raw water introduced is high turbidity of 5 NTU or more, as shown in FIG. 1, the introduced raw water is sequentially line-connected line mixer 110, flocculation tank 120, fiber filter 130, and membrane filter ( 140) in sequential order and filtered sequentially. To this end, the first and second switching valves 170 and 180 are switched so that both the first bypass line 150 and the second bypass line 160 are blocked.

Next, when the turbidity of the raw water flowing into the line mixer 110 is 1 NTU or more and less than 5 NTU of heavy water, the filtration process by the membrane filter 140, which is a subsequent process of the fiber filter 130, may be omitted. It is desirable to minimize energy consumption while satisfying the feed water quality of the process. This is because the filtration process by the membrane filter 140 consumes more energy than the filtration process by the fiber filter 130, while the water quality can be satisfied only by filtration by the fiber filter 130 for heavy turbidity raw water. . In order to implement this, as shown in FIG. 2, the first and second switching valves 170 and 180 block the first bypass line 150 to perform a filtration process by the fiber filter 130. On the other hand, the second bypass line 160 is switched to open to bypass the membrane filter 140.

Next, when the turbidity of the raw water flowing into the line mixer 110 is low turbidity water of less than 1 NTU, the filtration process by the membrane filter 140 can be used even without the pre-treatment filtration process fiber filter 130 Omitting the filtration step by) is preferable in terms of energy efficiency. To implement this, as shown in FIG. 3, the first and second switching valves 170 and 180 open the first bypass line 150 to bypass the fiber filter 130, and the first 2 bypass line 160 is cut off and controlled to pass through the membrane filter (140).

 According to the embodiment of the present invention as described above, in response to the turbidity of the incoming raw water, it is possible to change the flow line of the incoming raw water, such a change of the flow line can be made manually, but can be implemented automatically have. To this end, the water treatment device 100 may further include a turbidity detection sensor 191 and a valve control unit 192. Here, the turbidity sensor 191 detects the turbidity of the raw water flowing into the line mixer 110, transmits the information to the valve control unit 192, the valve control unit 192 corresponding to the turbidity of the raw water introduced The first and second switching valves 170 and 180 are controlled to be switched.

Hereinafter, the effects according to the embodiment of the present invention will be described based on the experimental data obtained by using the water treatment apparatus 100 described above.

First, the fiber filter 130 used in the experiment is a pressure type, the specifications of the fiber filter 130 used in the first experiment are shown in Table 1 below.

Item Specifications Size (mm) 390 (Ø) x 1,745 (H) Filtration area (m ² ) 0.66 Capacity (m ³ / day) 150 Textile Media material Polypropylene importance 0.91 Tensile force (N) 7,000

The experiment was performed for each of the case consisting of the fiber filter 130 and the membrane (Membrane) filter 140 and the case of using only the fiber filter. In addition, by adjusting the amount of 17% PAC, the inorganic coagulant 111 injected into each fiber filter 130, it was possible to confirm the correlation between the concentration of the inorganic coagulant 111 and the filtration efficiency.

 Table 2 below shows the turbidity and suspended solids concentration of the raw water.

Item unit at least maximum Average Turbidity NTU 15.0 547.0 126.0 Suspended solids (SS) mg / ℓ 23.0 900.0 204.5

First, low turbidity raw water (about 15 NTU) was filtered using a fiber filter 130. Table 3 below shows the amount of the inorganic coagulant 111 added in this case.

Flocculant
Treated Water Turbidity (NTU) Filtration duration
(minute) at least maximum Average Average removal rate (%) 0 mg / ℓ 7.0 9.0 7.68 48.8 180 10 mg / ℓ 1.9 6.1 2.39 84.1 85 20 mg / ℓ 0.18 4.3 0.30 98.0 50 30 mg / ℓ 0.32 4.2 0.66 95.6 30

Analysis of the above results, the average removal rate of 48.8% when the inorganic coagulant (111) was not added, whereas 98%, inorganic coagulant (111) 30 mg when the inorganic coagulant (111) is added 20 mg / l It can be seen that when / l was injected, it showed 95.6% (minimum turbidity 0.32 NTU). Therefore, the water quality of the filtered water is proportional to the proper amount of the inorganic coagulant 111, but it can be seen that the proportion is not higher than that. As a result, it can be seen that the addition of a large amount of inorganic coagulant 111 may lower the processing performance of the filtration device.

On the other hand, the filtration duration was inversely proportional to the amount of the inorganic coagulant 111. However, when the inorganic coagulant 111 was not added, the filtration duration, which lasted 3 hours or more, decreased to about 30 minutes when the 30 mg / l of the inorganic coagulant 111 was added. It was. As the amount of the inorganic coagulant 111 increased, the amount of Al (OH) ₃ , the suspended solids (SS) induced by the inorganic coagulant 111, increased, and the pore closing action was increased as the amount of the remaining inorganic coagulant 111 increased. It's fast.

Second, high turbidity raw water (about 300 NTU) was filtered using only the fiber filter 130. Table 4 below is the result of measuring the treated water quality and duration while adding the inorganic coagulant 111 in the range of 10 ~ 25mg / ℓ to determine the appropriate amount of flocculant for the high turbidity raw water of 300NTU or more.

Amount of flocculant
Treated Water Turbidity (NTU) Filtration duration
(minute) at least maximum Average Average removal rate (%) 10 mg / ℓ 10 43 21.9 92.7 55 15 mg / ℓ 12 32 14.4 95.2 45 20 mg / ℓ 6.9 21 7.5 97.5 35 25 mg / ℓ 10 25.2 12.3 95.9 20

Experimental results showed that the average turbidity of 7.5 NTU (removal rate 97.5%) was obtained when the inorganic coagulant (111) was injected at 20 mg / ℓ, and the filtration duration was about 35 minutes. This result is similar to that of low turbidity.

Third, the fiber filter 130 and the membrane filter 140 according to the embodiment of the present invention were operated for a long time (about 1 month). Table 5 below shows the treatment results in each of the fiber filter 130 and the membrane filter 140.

sample
Turbidity (NTU) Average turbidity removal rate
(%) at least maximum Average enemy 23 900 204.5 - Filtration Filtrate 0.2 19.2 6.4 95.3 Membrane filtration 0.2 0.32 0.26 99.4

As a result of continuously operating the water treatment apparatus according to an embodiment of the present invention under experimental conditions in which raw water of high turbidity was introduced for 1 month, the filtrate of the fiber filter 130 rose to 20 NTU depending on the turbidity of the raw water, but the membrane filter 140 ) Filtered water was stable around 0.3NTU. It was confirmed that the treatment effect was much better than the case of using one by connecting two filters with turbidity of the degree suitable for drinking water standards.

In the second experiment, the removal rate of the turbidity-inducing substance and the SDI value of the fiber filter 130 and the membrane filter 140 were observed.

For reference, the SDI value is an indicator that turbidity-inducing substance contained in the reverse osmosis membrane influent causes membrane fouling in the reverse osmosis membrane. It refers to the degree of sugar blockage of the membrane of 0.14 ㎛ of nominal pore due to the suspended substance contained in the water and is supplied to the reverse osmosis membrane. It is an index index to determine whether the pretreatment is appropriate by quantifying a small amount of suspended solids in the supply water.

Reverse osmosis membrane manufacturers generally order pretreatment for SDI 5.0 or less in the case of spiral wound reverse osmosis membrane, and it is called SDI (Silt Density Index) but also called SI (Silting Index) and FI (Fouling Index). Measure

The method of measurement is specified in ASTM D4189-95, which is briefly described. For 15 minutes, 500 ml of sample is equal to the initial time (T0) required to pass through the membrane filter (0.45 μm) at 206 kPa pressure. After filtration is continued, the time required for filtration of 500 ml is measured again (T1), and is calculated by the formula of SDI ₁₅ = (1-T0 / T1) * 100/15.

However, such SDI ₁₅ is often impossible to measure due to the infinite value of Ti in general water having some degree of turbidity such as surface water and lake water. the SDI ₅ and the SDI ₁₀ in the middle of measuring the SDI ₁₅ to obtain the reference material that is, by measuring the five bunjjae and 10 bunjjae SDI value while waiting for 15 minutes from the initial filtration reliability whether the SDI ₁₅ value is the last measurement To judge.

17% PAC
Input concentration
(mg / ℓ) Turbidity (NTU) SDI Influent fiber
filtrate UF
filtrate Kinds fiber
filtrate UF
filtrate
20

100

3.50

0.35
SDI ₅ - 13.1 SDI ₅ - 7.8 SDI ₁₅ - 5.9

In the design of the direct filtration method using the fiber filter 130, which is a mechanical filter, instead of the existing filtration process, the membrane filter 140 is provided to supply stable treated water in preparation for high turbidity raw water inflow. You will see that we need to connect

The fiber filter 130 is a device that can efficiently respond to changes in the water quality characteristics of raw water, and ensures stable water quality. The advantage is that full automation of the water treatment plant is possible.

 Since the pressure type fiber filter 130 needs to introduce raw water using a pump, it should use about half as little power as when using a conventional rapid sand filter. Since the detailed configuration of such a pressure-type fiber filter 130 is a known technique, description thereof will be omitted here.

On the other hand, if you want to remove the inorganic salts dissolved in the filtered water filtered by the membrane filter 140 to receive pure water can be used for high-filtration device 200, such as reverse osmosis membrane. Here, the detailed description of the filtration device itself by the reverse osmosis membrane is known, and thus the description thereof is omitted.

As described above, according to the water treatment apparatus according to the embodiment of the present invention, since the fiber filter 130 and the membrane filter 140 can be selected and applied flexibly to correspond to the turbidity of the raw water, in the water treatment process By minimizing unnecessary waste of energy, energy efficiency can be maximized.

In addition, since the fiber filter 130 is used instead of the sand filter for raw water of high turbidity, the required area of the equipment for filtration and the driving power cost can be reduced, and most of the turbidity-causing substances can be removed in advance. Membrane permeation flow rate of the phosphorus membrane filtration process can be significantly increased compared to the existing pretreatment system, thereby significantly reducing the construction cost and operating cost of the membrane filtration process.

The filtered water can be used according to its use or can be reused as not only drinking water but also seawater desalination, river maintenance water, agricultural and industrial water by removing dissolved salts by treating subsequent processes such as reverse osmosis membranes.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. The true technical protection scope of the invention should be defined by the technical spirit of the appended claims.

100: water treatment device 110: line mixer
111: inorganic coagulant 120: flocculation tank
130: fiber filter 140: membrane filter
150,160: first and second bypass line 170,180: first and second switching valve
191: turbidity sensor 192: valve control unit
200: advanced filtration device

Claims (5)

A line mixer 110 for rapidly mixing raw water of a treatment target to which the inorganic coagulant 111 is injected;
An agglomeration tank 120 connected in series with the line mixer 110 and growing the size of the flocculated flocs by aging raw water mixed with the inorganic coagulant 111;
A fiber filter 130 connected in series with the agglomeration tank 120 and directly filtering the agglomerated water flowing through the filtration layer made of a fiber filter; And
Is connected in series with the fiber filter 130, the water treatment device having a membrane filter 140 for filtering the incoming filtered water through the membrane (Membrane) again. The method according to claim 1,
A first bypass line 150 which bypasses the fiber filter 130 and directly connects the outlet of the flocculation tank 120 and the inlet of the membrane filter 140;
A second bypass line 160 which bypasses the membrane filter 140 and directly connects the outlet of the fiber filter 130 and the outlet of the membrane filter 140;
It is installed at the branch point of the first bypass line 150 branching from the outlet of the flocculation tank 120, the introduced flocculation water in one direction selected from the direction of the fiber filter 130 and the first bypass line 150 A first switching valve 170 for switching the flow path so as to flow only; And
It is installed at the branch point of the second bypass line 160 branched from the outlet of the fiber filter 130, the introduced filtration water selected one of the direction of the membrane filter 140 direction and the second bypass line 160 direction The water treatment device further comprises a second switching valve 180 for switching the flow path so as to flow only. The method according to claim 2,
When the turbidity of the raw water flowing into the line mixer 110 is high turbidity of 5 NTU or more, the first and second switching valves 170 and 180 are switched to adjust the first bypass line 150 and the first bypass line. Make sure that all of the second bypass lines 160 are blocked,
When the turbidity of the raw water flowing into the line mixer 110 is heavy turbid water of 1 NTU or more and less than 5 NTU, the first and second switching valves 170 and 180 are switched to adjust the first bypass line 150. ) Is blocked, the second bypass line 160 is opened to bypass the membrane filter 140,
When the turbidity of the raw water flowing into the line mixer 110 is low turbidity water of less than 1 NTU, the first and second switching valves 170 and 180 are switched to be adjusted to bypass the fiber filter 130. The first bypass line 150 is opened, and the second bypass line 160 blocks the water. The method according to claim 3,
Turbidity detection sensor 191 for detecting the turbidity of the raw water flowing into the line mixer 110; And
In response to the turbidity of the raw water detected by the turbidity sensor (191), the water treatment device further comprises a valve control unit (192) for adjusting so that the first and second switching valve (170) (180) is switched. The method according to any one of claims 1 to 4,
The membrane filter 140, the water treatment device including an MF membrane (Micro Filtration Membrane) or UF membrane (Ultra-Filtration Membrane).

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