KR20130123879A - High efficiency water treatment system using hollow fiber membrane and method of the same - Google Patents

Abstract

The present invention relates to a water treatment system using a hollow fiber membrane for reducing the final concentrate which maximizes the efficiency of water treatment by re-treating concentrate generated in the process of water treatment and minimizes the quantity of concentrate. The water treatment system using a hollow fiber membrane for reducing the final concentrate according to the present invention comprises a first hollow fiber membrane module for introducing raw water including materials to be separated or concentrate being discharged in the process of prior water treatment, conducting treatment using a hollow fiber membrane, and discharging wastewater and concentrate generated in the process to outside; and a second hollow fiber membrane module for introducing concentrate being discharged from the first hollow fiber membrane module, conducting re-treatment using a hollow fiber membrane, and discharging wastewater and concentrate generated in the process to outside. According to the water treatment system using a hollow fiber membrane for reducing the final concentrate, the efficiency of water treatment (recovery rate of wastewater) can be maximized (above 99.9%) and the quantity of final concentrate can be minimized. [Reference numerals] (11) Water storage tank;(22) Preprocessing;(31,41,51) Separating membrane tank;(60) Backwash/CIP;(AA) Water reservoir;(BB,CC,DD) Process water;(EE) Concentration tank

Description

High Recovery Hollow Fiber Membrane Filtration System and Operation Method for Reducing Final Concentrated Water {HIGH EFFICIENCY WATER TREATMENT SYSTEM USING HOLLOW FIBER MEMBRANE AND METHOD OF THE SAME}

The present invention relates to a hollow fiber membrane filtration apparatus, and more particularly, to a hollow fiber membrane filtration apparatus for reducing the final concentrated water to maximize the water treatment efficiency and minimize the amount of concentrated water by reprocessing the concentrated water generated during the water treatment process.

Separation membranes are very useful devices for separating solids and liquids, liquids and liquids, gases and gases, and liquids and gases without involving phase changes except in special cases, and are used for water treatment including wastewater treatment and water preparation. It is also widely used throughout the industry in the food and pharmaceutical sectors, in the separation of oxygen and nitrogen from the air and in the recovery of ammonia.

Separation membranes can be classified into various types according to their shape and separation performance. First, they are classified into flat membranes, tubular membranes, hollow fiber membranes, spiral wound membranes, etc., depending on their shape, and according to separation performance (pore size of membrane) Filtration membranes, reverse osmosis membranes, and the like.

The hollow fiber membrane module, which is used as a filter medium of the hollow fiber membrane water treatment device, has a high packing density and has an excellent membrane surface area per volume. The hollow fiber membrane chamber is composed of thousands to tens of thousands of hollow fiber membrane threads.

The general water treatment process using the hollow fiber membrane module having such characteristics includes a pretreatment step, a membrane separation step, a backwashing step and a washing step.

The pretreatment process removes contaminants from the raw water containing contaminants and supplies flocculants to form flocculation flocs.The membrane separation process treats the pretreated raw water using the hollow fiber membrane module and transfers the treated water to the drain. The concentrated water is transferred to the concentration tank, and the backwashing and washing processes are used to wash the hollow fiber membrane module using a portion of the treated water.

In the case of the conventional water treatment system using a hollow fiber membrane, the above-described processes are performed only as a first step, and thus, limitations such as an increase in the amount of concentrated water according to the inflow quality and the system recovery rate are caused when the capacity is increased due to the enlargement of the system.

An object of the present invention was devised to solve the conventional problems as described above, in order to maximize the water quality improvement and water treatment efficiency (recovery rate) by applying a plurality of independent systems in the enlargement of the water treatment system using a hollow fiber membrane The present invention provides a hollow fiber membrane filtration apparatus for reducing the final concentrated water, which can reduce the final concentrated water quantity and raise the production quantity to the limit.

In the present invention, the hollow fiber membrane filtration device for reducing the final concentrated water is introduced into the raw water containing the separation target material or the concentrated water discharged from the previous water treatment, and treated using the hollow fiber membrane, and the treated water and the concentrated water generated in this process. Primary hollow fiber membrane module to discharge each to the outside; And a secondary hollow fiber membrane module for introducing the concentrated water discharged from the primary hollow fiber membrane module and reprocessing the hollow fiber membrane, and discharging the treated water and the concentrated water generated in this process to the outside, respectively.

The first and second hollow fiber membrane modules operate independently except for the transfer of concentrated water.

Secondary hollow fiber membrane module is provided with a plurality so that repeated reprocessing of the concentrated water produced in each step.

The first and second hollow fiber membrane modules include a separation membrane tank for filtering contaminants using a hollow fiber membrane after introducing raw water or concentrated water; A blower for supplying air to the separation membrane to separate the contaminants attached to the membrane; Process pump for discharging the treated water generated in the membrane tank to the drainage; And a discharge pump for discharging the concentrated water generated in the separation membrane tank.

The hollow fiber membrane filtration apparatus for reducing the final concentrated water of the present invention further includes a cleaning unit for cleaning the separation membrane tank by using some of the treated water that has passed through the process pump.

The washing unit cleans the separation tank using only the treated water or adds a chemical to the treated water to clean the separation tank.

The hollow fiber membrane filtration device for reducing the final concentrated water of the present invention recovers treated water to recover the treated water to a raw water storage tank for storing the raw water supplied to the primary hollow fiber membrane module when the quality of the treated water discharged from the separation membrane is deteriorated. Includes more wealth.

Condensate water discharge pipe discharged from the separation membrane tank consists of a reprocessing transport pipe for transporting the concentrated water for reprocessing, and a thickening tank transport pipe for transporting the concentrated water to the concentration tank. Concentrated water control valve for flow control is provided respectively.

(a) When the concentrated water discharged from the previous stage module among the hollow fiber membrane modules is transferred to the next stage module, the concentrated water control valve of the reprocessing feed pipe is opened and the concentrated water control valve of the thickener feed pipe is closed. (b) When the concentrated water discharged from the previous stage of the hollow fiber membrane modules is transferred to the condenser, the condensate control valve of the reprocessing conveying line is closed and the condensate control valve of the condenser conveying line is opened, and (c) When the brine is distributed and transferred to the next level of modules and concentrators, each brine control valve is opened and its opening is adjusted.

The hollow fiber membrane filtration apparatus for reducing the final concentrated water of the present invention further includes a pretreatment unit for pretreatment of raw water transferred to the primary hollow fiber membrane module.

The pretreatment unit may include: a strainer for removing impurities contained in raw water; And a cohesive mixing tank for selectively supplying coagulant to the raw water according to the state of the raw water passing through the strainer to control organic matter and dissolved substances in the raw water.

In the process of introducing the concentrated hollow water into the secondary hollow fiber membrane module, a flocculant is selectively formed in the concentrated water by injecting a flocculant into the concentrated water according to the state of the concentrated water.

The concentrated water discharged from the hollow fiber membrane module positioned at the final stage of each hollow fiber membrane module is transferred to the concentration tank.

According to the hollow fiber membrane filtration device for reducing the final concentrated water of the present invention has the following effects.

First, raw water containing contaminants is reprocessed while passing through the hollow fiber membrane module of various stages, thereby maximizing water treatment efficiency (treatment rate of recovery water) (more than 99.9%) and minimizing the final concentrated water quantity.

Second, by connecting a plurality of independent hollow fiber membrane modules to adjust the operating conditions for each module it is possible to minimize the influence of influent water quality and other modules. By combining the pretreatment process at each stage, it is possible to selectively treat the fluctuation of inflow water quality. It is possible to freely control the whole amount of the concentrated water treatment or transfer to the concentration tank.

Third, when there is a problem in the water quality of the treated water is made to reprocess the treated water can be solved the problem of poor water quality.

1 is a system diagram of the hollow fiber membrane filtration device for reducing the final concentrated water of the present invention.
Figure 2 is a system diagram showing a process of washing the separation membrane bath.
3 is a system diagram showing a process of recovering treated water.

Hereinafter, the hollow fiber membrane filtration apparatus for reducing the final concentrated water of the present invention will be described in detail with reference to the accompanying drawings.

1 is a system diagram of a hollow fiber membrane filtration device for reducing the final concentrated water of the present invention, Figure 2 is a system diagram showing a process of washing the separation membrane tank, Figure 3 is a system diagram showing a process of recovery of the treated water.

The hollow fiber membrane filtration device for reducing the final concentrated water according to the present invention is a raw water supply unit 10, pretreatment unit 20, the first hollow fiber membrane module 30, the second hollow fiber membrane module 40, the third hollow fiber membrane module 50, a washing unit 60, and a treated water recovery unit 70.

The raw water supply unit 10 that supplies the raw water stored and saved by introducing a number of containing a separated substance, such as a waste water containing a contaminant source as a pre-processing section 20, the raw water reservoir 11 to which raw water is stored and , A raw water supply pump 12 for supplying the raw water of the raw water storage tank 11 to the pretreatment unit 20.

The pretreatment unit 20 removes the contaminants contained in the raw water supplied through the raw water supply pump 12 and supplies a flocculant to form a flocculation floc. The strainer 21 removes the contaminants contained in the raw water, and the strainer. A cohesive mixing tank 22 is provided to supply the coagulant to the raw water passed through the 21 to increase the size while the fine organic matter in the raw water aggregates with each other. Polyaluminum chloride (PACL) etc. are used as a flocculant. In the case of the cohesion mixing tank 22 may be selectively applied according to the state of the raw water. That is, when aggregation is not necessary according to the water quality conditions of the raw water, the aggregation process in the flocculation mixing tank 22 can be omitted.

The first hollow fiber membrane module 30 treats the raw water that has passed through the pretreatment unit 20 using the hollow fiber membrane, and separates the treated water and the concentrated water generated in this process and is discharged to the outside. The first hollow fiber membrane module 30 includes a first separation membrane tank 31, a first blower 32, a first process pump 33, and a first discharge pump 34.

The first separation membrane tank 31 accommodates raw water therein and immerses the hollow fiber membrane in raw water to filter particulate matter or pathogenic microorganisms contained in the raw water. As such, the first separation membrane tank 31 may be formed in an immersion type, but is not limited thereto.

The first blower 32 supplies air to the first separation membrane tank 31 to separate contaminants attached to the surface of the hollow fiber membrane from the hollow fiber membrane.

The first process pump 33 transfers the treated water (water from which the contaminant is removed) generated in the first separation membrane tank 31 to the drainage, and when the first separation membrane tank 31 is washed, the first washing water is washed. Transfer to the separation membrane tank 31 so that the first separation membrane 31 is cleaned.

The first discharge pump 34 discharges the concentrated water (water remaining in the first separation membrane tank without removing contaminants) generated in the first separation membrane tank 31 to the outside. The concentrated water that has passed through the first discharge pump 34 is divided into a first reprocessing conveying pipe 35 and a first concentration tank conveying pipe 36 and selectively conveyed, or conveyed while the conveying amount is adjusted. The concentrated water that has passed through the first discharge pump 34 is transferred to the second hollow fiber membrane module 40 through the first reprocessing transfer pipe 35 or to the concentration tank through the first concentration tank transfer pipe 36. The first reprocessing feed pipe 35 and the first concentrate tank feed pipe 36 are each provided with a concentrated water control valve 37 for adjusting the flow rate.

When the concentrated water discharged from the first hollow fiber membrane module 30 is entirely transferred to the second hollow fiber membrane module 40, the concentrated water control valve 37 of the first reprocessing feed pipe 35 is opened and the first concentrated tank feed pipe The concentrated water control valve 37 of 36 is closed. When the concentrated water discharged from the first hollow fiber membrane module 30 is transferred to the concentration tank, the concentrated water control valve 37 of the first reprocessing transfer pipe 35 is closed and the concentrated water of the first concentration tank feed pipe 36 is closed. The control valve 37 is opened. When both of the concentrated water control valve 37 is opened and the opening degree is adjusted, the concentrated water is simultaneously transferred to the second hollow fiber membrane module 40 and the concentration tank.

The second hollow fiber membrane module 40 is to reprocess the concentrated water supplied from the first hollow fiber membrane module 30 using the hollow fiber membrane, and the second separation membrane tank 41, the second blower 42, and the second It includes a process pump 43, a second discharge pump 44, a second reprocessing transfer pipe 45, a second concentrated tank transfer pipe 46 and a concentrated water control valve 47. Here, since the action of each component constituting the second hollow fiber membrane module 40 is the same as that of the first hollow fiber membrane module 30, description thereof will be omitted.

The third hollow fiber membrane module 50 is to finally reprocess the concentrated water supplied from the second hollow fiber membrane module 40 using the hollow fiber membrane, the third separation membrane tank 51, the third blower 52, The third process pump 53 and the third discharge pump 54 is included. Here, since the action of each component constituting the third hollow fiber membrane module 50 is the same as that of the first hollow fiber membrane module 30, description thereof will be omitted. However, since the third hollow fiber membrane module 50 performs the final water treatment, the concentrated water passing through the third discharge pump 54 is transferred to the total concentration tank.

The cleaning unit 60 cleans each of the separation membrane tanks 31, 41, and 51 using a portion of the treated water that has passed through the first hollow fiber membrane module 30. The cleaning unit 60 is provided with only one irrespective of the number of the hollow fiber membrane module to clean all the separation membrane tank (31, 41, 51). Of course, each of the hollow fiber membrane modules may be provided with a cleaning unit 60 to separately clean the separation membrane tanks 31, 41, and 51.

The washing unit 60 backwashes the hollow fiber membrane modules 30, 40 and 50 with only the treated water, and adds a chemical to the treated water to clean the hollow fiber membrane modules 30, 40 and 50. Chemical treatment is optionally performed. In the cleaning process through the cleaning unit 60, as shown in FIG. 2, some of the treated water passing through the process pumps 33, 43, 53 is introduced into the cleaning unit 60, stored, and cleaned. When the chemicals are added or not added, the hollow fiber membrane modules 30, 40, and 50 are supplied to the separation membrane tanks 31, 41, and 51 through the process pumps 33, 43, and 53. ) Will be cleaned. In the cleaning process, the flow is controlled so that the washing water is only transferred to the hollow fiber membrane modules 30, 40 and 50 without being transferred to the drainage basin. This flow control is achieved through flow control valves (not shown) provided in the conduit. Meanwhile, in the present embodiment, the washing water is supplied using the process pumps 33, 43, and 53, but is not limited thereto, and the washing water is selectively used by using a backpulse pump and a cleaning (CIP) pump. It can also be configured to be supplied.

The treated water recovery unit 70 is configured to recover the treated water to the raw water storage tank 11 without transferring the treated water to the wastewater when the treated water passing through each of the hollow fiber membrane modules 30, 40 and 50 is contaminated. Recovery of the treated water may be made from all of the hollow fiber membrane modules 30, 40, 50 depending on the contamination state, or may be selectively made for each hollow fiber membrane module 30, 40, 50. The treated water recovery unit 70 connects the treated water conveying pipes 38, 48, and 55 of each hollow fiber membrane module 30, 40, 50 to the raw water storage tank 11. (72) and (73). As shown in FIG. 3, in the process of recovering the treated water to the raw water storage tank 11, the flow is adjusted such that the treated water is not transferred to the water reservoir but only to the raw water storage tank 11. This flow control is achieved through flow control valves (not shown) provided in the conduit.

Hereinafter, the process of the water treatment through the hollow fiber membrane filtration device for reducing the final concentrated water of the present invention configured as described above will be described.

First, the raw water for the water treatment is introduced into the raw water storage tank 11 and stored and then transferred to the pretreatment unit 20 through the raw water supply pump 12. In the strainer 21, the contaminants contained in the raw water are removed, and in the cohesion mixing tank 22, the fine organic matters in the raw water are agglomerated with each other by the coagulant to form flocs and increase in size. The flocculant injection in the flocculation mixing tank 22 is selectively performed according to the state of raw water. In other words, when aggregation is not necessary according to the water quality conditions of the raw water, the aggregation process in the cohesion mixing tank 22 may be omitted.

The raw water of which the size of the organic material is increased while forming the flocculation floc is transferred to the first separation membrane tank 31 of the first hollow fiber membrane module 30. In the first separation membrane tank 31, particulate matter or pathogenic microorganisms contained in raw water are filtered out by an immersion type or a pressurized hollow fiber membrane. The contaminated material is filtered and cleared, and the treated water is transferred to the drain by the first process pump 33. The concentrated water remaining in the first separation membrane tank 31 without being processed by the hollow fiber membrane is discharged by the first discharge pump 34.

The concentrated water discharged by the first discharge pump 34 is transferred to the second separation membrane tank 41 of the second hollow fiber membrane module 40 for reprocessing, or is transferred to the concentration tank. In the process of transferring the concentrated water to the second separation membrane tank 41, a flocculant is selectively supplied to the concentrated water according to the state of the concentrated water so that the size of the floc increases as the organic matter contained in the concentrated water aggregates with each other.

After the concentrated water transferred to the second separation membrane tank 41 of the second hollow fiber membrane module 40 is retreated, the treated water is discharged by the second process pump 43 as in the first hollow fiber membrane module 30. The concentrated water is discharged by the second discharge pump 44.

The concentrated water discharged by the second discharge pump 44 is transferred to the third separation membrane tank 51 of the third hollow fiber membrane module 50 for reprocessing, or is transferred to the concentration tank. In the process of transferring the concentrated water to the third separation membrane tank 51, a flocculant is selectively supplied to the concentrated water according to the state of the concentrated water so that the organic matter contained in the concentrated water aggregates with each other to increase the size of the floc.

After the concentrated water transferred to the third separation membrane tank 51 of the third hollow fiber membrane module 50 is reprocessed, the treated water is transferred to the drainage by the third process pump 53, and the concentrated water is discharged to the third discharge pump. After discharged by 54, the whole quantity is transferred to the concentration tank.

Some of the treated water transferred through the first process pump 33 is stored in the cleaning unit 60 and then used to clean the hollow fiber membrane modules 30, 40, 50. At the time of washing, the water treatment process is stopped and chemicals are added to the treated water stored in the washing unit 60 or only the treated water is supplied to the hollow fiber membrane modules 30, 40, and 50 so that the hollow fiber membrane modules 30 and 40 are treated. 50 is cleaned. The supply of the washing water to the hollow fiber membrane modules 30, 40 and 50 is performed through the process pumps 33, 43 and 53, respectively.

If the treated water produced from the hollow fiber membrane module 30, 40, 50 is contaminated, if the treated water is transferred to the drainage, it becomes an additional contaminant, so the contaminated treated water is not transferred to the drainage, but the treated water recovery unit 70. After being recovered to the raw water storage tank 11 through the several steps as described above are reprocessed.

On the other hand, the first, second, third hollow fiber membrane module 30, 40, 50 is operated independently for each module except the transfer of the concentrated water.

[Example]

When the amount of raw water introduced is 100,000㎥ / d, the yield of treated water and the yield of concentrated water in each step are shown in Table 1 below.

Maximized recovery system
Remarks

Stage Recovery rate Inflow Treatment flow rate Discharge flow Driving Flux (%) ㎥ / d ㎥ / d ㎥ / d LMH
㎥ / ㎡ · hr 1st 98 100,000 98,000 2,000 30 or more Flux adjustment according to the driving situation 2nd 95 2,000 1,900 100 20 ~ 30 3nd 90 100 90 10 15 or less Total 99.99 100,000 99,990 10

As shown in Table 1, in the first stage (the first hollow fiber membrane module stage), raw water was supplied to 100,000 m 3 / d to produce 98,000 m 3 / d of treated water, and 2,000 m 3 / d of concentrated water was produced. Therefore, the treated water recovery in the first stage is 98%.

In the second stage (second hollow fiber membrane module stage), 2,000 m 3 / d of concentrated water generated in step 1 was introduced to generate 1,900 m 3 / d of treated water, and 100 m 3 / d of concentrated water was generated. Therefore, the treated water recovery in the second stage is 95%.

In the third stage (third hollow fiber membrane module stage), 100 ㎥ / d of the concentrated water produced in the second step was introduced to generate 90 ㎥ / d of treated water, and 10 ㎥ / d concentrated water was generated. Therefore, the treated water recovery in the third stage is 90%.

As described above, the recovery rate of the individual modules is more than 90%, and 99,990㎥ / d of treated water is generated from 100,000㎥ / d of raw water during three stages of water treatment, so the recovery rate of the treated water is 99.99%. It can be seen that the high efficiency.

Table 2 shows an example of applying the recovery rate according to the inflow water quality.

Influent Turbidity (NTU) <20 21-75 75-300 300-500 > 500 Recovery rate (%) 99 98 95 93 90

As described above, by combining a plurality of independent water treatment systems, it is possible to cope with fluctuations in the water quality of raw water, to minimize the final concentrated water amount, and as a result, to obtain a high amount of treated water and to minimize the final concentrated water amount.

On the other hand, in the water treatment process using the hollow fiber membrane module, in order to obtain permeated water (treated water) passing through the hollow fiber membrane, pressurized feed water (Feed water) flowing into the hollow fiber membrane module at an appropriate pressure according to the shape of the module, or module to raw water Should be dipped and inhaled. In this case, the design factors of hollow fiber membrane module system, such as flux, system recovery rate and system differential pressure (TMP), which reflect site-specific characteristics such as concentration and temperature of raw water, are factors that determine proper pressure. It can be distinguished by the factor that is reflected.

At this time, the equation for determining the operating flux (Flux) is as follows.

Flux = flow rate / membrane area (area per module * number of modules) ------- Equation-1

-Flux (LMH, ㎥ / ㎡ · hr): Permeate flow rate of fluid per unit area (㎡) of membrane for the unit time (㎥)

-The treatment flow rate is controlled by the operation rate of the process pump and the calculated flux is applied as a design factor.

-Initial Flux setting by referring to operation manual guideline according to membrane type and manufacturer's inflow water quality

-Calculate the number of modules according to the system recovery rate and throughput

Increasing the pump operation rate to increase the permeate flow rate per unit area increases the membrane permeation pressure and speeds up the contamination rate. In order to reduce the contamination load of the membrane due to deterioration of influent quality, the permeate flow rate is lowered by controlling the recovery rate and the flux to maintain a proper operating pressure.

The downstream influent has a high content of particles that do not penetrate the preceding membrane. The flocculant injection increases the floc size of the particles, making it easy to process the sedimentation, and controlling the contamination progress of the membrane by reducing the operating pressure of the process pump with relatively low recovery rate and low permeate flow rate.

As described above, the present invention has been described based on the preferred embodiments, but the present invention is not limited to the specific embodiments, and those skilled in the art may change the scope within the scope of the claims. Can be. For example, in the present embodiment, only one second hollow fiber membrane module is provided, but the present invention is not limited thereto, and one or more hollow fiber membrane modules having the same type as the second hollow fiber membrane module are additionally disposed between the second hollow fiber membrane module and the third hollow fiber membrane module. It may be provided to enable the repetitive treatment of the concentrated water.

10: raw water supply unit 11: raw water storage tank
12: raw water supply pump 20: pretreatment unit
21: strainer 22: cohesion mixing tank
30: first hollow fiber membrane module 31: the first separation membrane tank
32: first blower 33: first process pump
34: 1st discharge pump 35: 1st reprocessing conveying line
36: first concentration tank transfer pipe 37: concentrated water control valve
38: treated water transport pipe 40: second hollow fiber membrane module
41: second separation membrane 42: second blower
43: second process pump 44: second discharge pump
45: 2nd reprocessing conveying line 46: 1st concentration tank conveying line
47: concentrated water control valve 48: treated water delivery pipe
50: third hollow fiber membrane module 51: third separation membrane tank
52: 3rd blower 53: 3rd process pump
54: third discharge pump 55: treated water transport pipe
60: washing unit 70: treated water recovery unit
71,72,73: Treatment water return line

Claims (13)

A primary hollow fiber membrane module for introducing raw water containing a material to be separated or concentrated water discharged from a previous water treatment process using a hollow fiber membrane, and discharging the treated water and the concentrated water generated in this process to the outside; And
Final condensate reduction; including; secondary hollow fiber membrane module for introducing the concentrated water discharged from the primary hollow fiber membrane module and reprocessing the hollow fiber membrane, and discharges the treated water and the concentrated water generated in the process to the outside, respectively Hollow fiber membrane filtration device. The method of claim 1,
The first and second hollow fiber membrane module is a hollow fiber membrane filter device for reducing the final concentrated water, characterized in that it is operated independently except the transfer of concentrated water. 3. The method of claim 2,
The second hollow fiber membrane module is provided with a plurality of hollow fiber membrane filtration device for reducing the final concentrated water, characterized in that to be reprocessed of the concentrated water produced in each step. 4. The method according to any one of claims 1 to 3,
The first and second hollow fiber membrane module,
A separation membrane tank for filtering contaminants using the hollow fiber membranes after introducing the raw water or concentrated water;
A blower for supplying air to the separation membrane tank to separate the contaminants attached to the membrane;
A process pump for discharging the treated water generated in the membrane tank to a drainage basin; And
And a discharge pump for discharging the concentrated water generated in the separation membrane tank. 5. The method of claim 4,
The hollow fiber membrane filtration device for reducing the final concentrated water, characterized in that it further comprises a cleaning unit for cleaning the separation membrane tank using a portion of the treated water passed through the process pump. The method of claim 5,
The cleaning unit may include:
The hollow fiber membrane filtration device for reducing the final concentrated water, characterized in that for cleaning the separation membrane tank using only the treated water, or to wash the separation membrane tank by adding a chemical to the treated water. 5. The method of claim 4,
When the water quality of the treated water discharged from the separation membrane is deteriorated final concentration further comprising a treated water recovery unit for recovering the treated water to the raw water storage tank for storing the raw water supplied to the primary hollow fiber membrane module Hollow fiber membrane filtration device for water reduction. 5. The method of claim 4,
The conveying pipe of the concentrated water discharged from the membrane tank consists of a reprocessing conveying pipe for conveying the concentrated water for reprocessing, and a condensing tank conveying pipe for conveying the concentrated water to the thickening tank, and the reprocessing conveying pipe and the thickening tank conveying. The hollow fiber membrane filtration apparatus for reducing the final concentrated water, characterized in that each is provided with a concentrated water control valve for controlling the flow rate. 9. The method of claim 8,
(a) When the concentrated water discharged from the previous stage of the hollow fiber membrane module is transferred to the next stage of the total amount of the concentrated water control valve of the reprocessing feed pipe is opened and the concentrated water control valve of the thickening tank feed pipe Closed,
(b) when the concentrated water discharged from the previous stage of the hollow fiber membrane modules is transferred to the concentration tank, the concentrated water control valve of the reprocessing feed pipe is closed and the concentrated water control valve of the thickener feed pipe is opened;
(c) The hollow fiber membrane filtration apparatus for reducing the final concentrated water, characterized in that when the concentrated water is distributed to the module and the concentration tank of the next stage, all the concentrated water control valves are opened and their opening degree is controlled. 4. The method according to any one of claims 1 to 3,
The hollow fiber membrane filtration device for reducing the final concentrated water, further comprising a pre-treatment unit for pre-processing the raw water to be transferred to the primary hollow fiber membrane module. The method of claim 10,
The pre-
A strainer for removing impurities contained in raw water; And
And a flocculation mixing tank for selectively supplying a flocculant to the raw water according to the raw water passing through the strainer to control organic matter and dissolved substances in the raw water. 12. The method of claim 11,
Hollow fiber membrane filtration for reducing the final concentrated water, characterized in that the flocculation floc is formed in the concentrated water by selectively injecting the flocculant into the concentrated water in accordance with the state of the concentrated water in the process of introducing the concentrated water into the secondary hollow fiber membrane module Device. 4. The method according to any one of claims 1 to 3,
Concentrated water discharged from the hollow fiber membrane module positioned in the final step of each of the hollow fiber membrane module hollow fiber membrane filtration device for reducing the final concentrated water, characterized in that the transfer to the concentration tank.

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