KR101987924B1 - Apparatus and method for injecting oxidizing agent capable of corresponding dissolved manganese in purification process of membrane filtration - Google Patents

Abstract

The present invention relates to an apparatus for injecting an oxidant capable of coping with complex water quality of a water source in a complex water treatment system, and a method thereof. More specifically, when dissolved manganese is present in the treated water produced by a membrane filtration process, backwashing is performed without sodium hypochlorite. Sodium hypochlorite is sent to an oxidant contact bath rather than being injected into the piping connected to a backwashing pump. Sodium hypochlorite transferred to the oxidant contact bath is mixed with an oxidant to promote oxidation of dissolved manganese.

Description

Apparatus and method for oxidant injection capable of dissolving manganese in membrane filtration water purification process {APPARATUS AND METHOD FOR INJECTING OXIDIZING AGENT CAPABLE OF CORRESPONDING DISSOLVED MANGANESE IN PURIFICATION PROCESS OF MEMBRANE FILTRATION}

The present invention relates to an apparatus and a method for injecting an oxidant capable of coping with the complex water quality of a water source in a complex water treatment system, and more particularly, dissolved manganese in dissolved manganese treated water in the treated water produced by the membrane filtration process. If present, the backwash is performed without sodium hypochlorite, but sodium hypochlorite is not injected into the pipe connected to the backwash pump, but the sodium hypochlorite transferred to the oxidant contacting tank is mixed with the oxidizing agent and dissolved in manganese. The present invention relates to an oxidant injection device and a method capable of counteracting dissolved manganese in a membrane filtration water purification process for promoting oxidation of oxidized water.

Conventional methods for removing raw water dissolved manganese include a method of injecting and treating oxidizing materials such as chlorine and ozone, and eluting dissolved manganese to insoluble and then removing them in a precipitation process, or in Korean Registered Patent Publication No. 10-1494302 A method of removing by attaching to manganese to which manganese is attached as disclosed in the present invention is used.

However, the use of chlorine has a problem in that trihalomethane (THM), which is a type of carcinogen, is difficult to determine the injection amount, and when manganese sand is used, a wide required site is required for treatment.

Sodium permanganate, recently registered as a water treatment agent, is an oxidizing agent with high dissolved manganese removal performance, and can be treated with a filter medium by insolubilizing dissolved manganese by an oxidizing effect without applying manganese sand.

However, since it is an expensive drug, it may lead to an increase in production cost when a large amount is used, and when injected in an excessive amount, the chromaticity of the treated water may increase, and an appropriate injection amount needs to be determined.

In the membrane filtration process, sodium hypochlorite is mainly used in the backwashing process to alleviate the contamination of the membrane. As described in Korean Patent Publication No. 10-0954571.

Sodium hypochlorite is responsible for removing some of the organic substances attached to the membrane and at the same time prevent the growth of microorganisms in the tube.

However, when dissolved manganese is present, manganese adheres to the inner side of the membrane by sodium hypochlorite used in the process for backwashing, causing contamination and deteriorating treatment performance.

Domestic Patent Publication No. 10-1494302 Domestic Patent Publication No. 10-0954571

The present invention is to solve the above problems, if the dissolved manganese is present in the dissolved manganese treated water produced by the membrane filtration process, the backwashing without sodium hypochlorite, but sodium hypochlorite is reverse Sodium hypochlorite, which is not injected into the pipe connected to the washing pump and is transferred to the oxidant contacting tank and is transferred to the oxidant contacting tank, is mixed with the oxidizing agent to enable dissolved manganese response in membrane filtration water purification process to promote oxidation of dissolved manganese. It is an object of the present invention to provide an oxidant injection device and method.

In addition, the present invention is the removal efficiency of manganese by the injected oxidant is lowered, and in the situation that can not increase the injection amount of the oxidant due to the concern about the chromaticity, sodium hypochlorite used in the backwashing process of the membrane to remove the manganese removal efficiency It is another object of the present invention to provide an oxidant injection device and method capable of preventing dissolved manganese in a membrane filtration water purification process that can prevent contamination of the film by manganese and prevent color generation due to excessive injection of oxidant. .

Features of the present invention for achieving the above object,

A raw water tank in which raw water is stored; A first manganese measuring device for measuring the manganese concentration of the raw water supplied to the raw water tank; A TOC measuring device for measuring the total organic carbon (TOC) concentration of the raw water supplied to the raw water tank; An oxidant contacting tank for bringing raw water of the raw water tank into contact with an oxidant; An oxidant reservoir for supplying the oxidant to the oxidant contact tank; A pretreatment tank for pretreatment of raw water discharged in contact with the oxidant in the oxidant contact tank; A separation membrane for filtering the pretreatment water discharged from the pretreatment tank; A treated water tank for storing the treated water discharged from the separator and supplying the treated water to backwash water during backwashing of the separator; A sodium hypochlorite storage tank for supplying sodium hypochlorite to the oxidant contact tank and the treated water tank; A second manganese measuring device for measuring manganese concentration of the treated water discharged from the separator to the treated water tank; A chromaticity measuring device for measuring the chromaticity of the treated water discharged from the separator to the treated water tank; A discharge tank for storing the concentrated water and the backwash water discharged from the separator; And measuring manganese concentration and TOC concentration of the raw water through the first manganese measuring instrument and the TOC measuring instrument to control the injection amount of the oxidant according to the TOC concentration, and the manganese concentration and chromaticity of the treated water through the second manganese measuring instrument and the chromaticity measuring instrument. When the membrane was backwashed accordingly, the sodium hypochlorite was supplied to the treated water to backwash the separator, but when the manganese concentration of the treated water was greater than or equal to a predetermined value, the supply of the sodium hypochlorite to the separator was blocked. And a control unit for supplying the sodium hypochlorite to the oxidant contact tank.

Here, the oxidant injector capable of coping with dissolved manganese in the membrane filtration water treatment process, the first flow meter for measuring the flow rate of the raw water discharged from the raw water tank to the oxidant contact tank; A second flow meter for measuring the flow rate of the oxidant discharged from the oxidant reservoir; A third flow meter for measuring the flow rate of backwash water supplied from the treated water tank to the separator; A fourth flow meter for measuring the flow rate of the sodium hypochlorite discharged from the sodium hypochlorite storage tank; A first chemical pump for pressurizing the oxidant discharged from the oxidant reservoir; A second pharmaceutical pump for pressurizing said sodium hypochlorite discharged from said sodium hypochlorite storage tank; A backwash pump for supplying the treated water of the treated tank to the backwash water of the separator; And first and second solenoid valves for opening and closing a conduit to selectively supply the sodium hypochlorite discharged from the sodium hypochlorite storage tank to the separator or the oxidant contact tank.

Here too, the oxidizing agent is sodium permanganate or potassium permanganate.

Here, the controller measures the manganese concentration and TOC concentration of the raw water through the first manganese measuring instrument and the TOC measuring instrument and injects the oxidant at 1.7 times the manganese concentration present in the raw water when the TOC concentration is less than 3.0 mg / L. When the TOC concentration is 3.0 mg / l or more, the oxidizing agent is injected at 5 times the manganese concentration, and the injection amount of the oxidizing agent is measured by the first flowmeter by measuring the flow rate flowing from the raw water tank into the oxidant contacting tank with respect to the flow rate. The first chemical pump controls the flow rate of the oxidant.

Here, the control unit measures the manganese concentration and chromaticity of the treated water through the second manganese measuring instrument and the chromaticity measuring instrument when backwashing, and when the manganese concentration and chromaticity are less than the reference value, the second chemical pump and the third and fourth flowmeters are measured. The sodium hypochlorite was supplied to the separator at a concentration of 3 to 5 mg / l, and when the manganese concentration of the treated water was 0.01 mg / l or more, the first and second solenoid valves were controlled to reverse the sodium hypochlorite. Block the supply to the washing water, and to be injected with the oxidant to the oxidant contact tank, if the manganese concentration of the treated water is 0.01mg / L or more, less than 5 degrees of chromaticity by increasing the injection amount of the oxidant to double the manganese removal efficiency When the concentration of manganese in the treated water is 0.01 mg / l or more and the chromaticity is 5 degrees or more, the injection amount of the oxidant is reduced by half, and the sodium hypochlorite By increasing the dosage of two times to prevent the occurrence chromaticity.

Another feature of the invention,

An oxidant injector capable of coping with dissolved manganese in the membrane filtration water purification process, comprising: a raw water measurement step of measuring manganese concentration and TOC concentration of raw water flowing into a raw water tank; An oxidant injection amount control step of controlling the injection amount of the oxidant injected into the oxidizing tank contact tank according to the TOC concentration; A treated water measuring step of measuring manganese concentration and chromaticity of the treated water; And backwashing the separation membrane by supplying sodium hypochlorite to the treated water when backwashing the separation membrane. When the manganese concentration of the treated water is higher than a predetermined concentration value, the supply of sodium hypochlorite to the separation membrane is blocked, and the sodium hypochlorite It is characterized by consisting of a backwashing step of injecting into the oxidant contact bath.

Wherein the oxidant is sodium permanganate or potassium permanganate.

Here, the oxidant injection amount control step measures the manganese concentration and TOC concentration of the raw water, if the TOC concentration is less than 3.0mg / L, the oxidant is injected at 1.7 times the manganese concentration present in the raw water, the TOC concentration is 3.0mg / The oxidant is injected at 5 times the concentration of manganese, but the injection amount of the oxidant controls the flow rate of the oxidant in comparison with the flow rate flowing from the raw water tank to the oxidant contact tank.

Here, the backwashing process measures the manganese concentration and the chromaticity of the treated water, and when the manganese concentration and the chromaticity are less than the reference value, the sodium hypochlorite concentration is supplied to the separator at 3 to 5 mg / l, and the treated water is When the manganese concentration is 0.01 mg / L or more, the sodium hypochlorite is prevented from being supplied to the backwash water and injected into the oxidant contact tank together with the oxidant, but the manganese concentration of the treated water is 0.01 mg / L or more and the chromaticity is 5 degrees. If less than 2 times the amount of the oxidant is increased to increase the manganese removal efficiency, when the concentration of manganese in the treated water is 0.01mg / L or more, 5 degrees or more, the amount of the oxidant is reduced by half, the hypochlorous acid Double the amount of sodium injected to prevent color development.

According to the oxidant injection apparatus and method capable of dissolving manganese in the membrane filtration purified water treatment process of the present invention configured as described above, when dissolved manganese is present in the dissolved manganese treated water in the treated water produced by the membrane filtration process, hypochlorous acid Backwashing is performed without sodium, but sodium hypochlorite is not injected into the pipe connected to the backwash pump, but is transferred to the oxidant contact bath, and sodium hypochlorite transferred to the oxidant contact bath is mixed with the oxidant to promote oxidation of dissolved manganese. .

In addition, according to the present invention, the manganese removal efficiency is lowered by the conventionally injected oxidant, and when the amount of oxidant cannot be increased due to the concern about chromaticity, the sodium hypochlorite used in the backwashing process of the membrane is injected to remove the manganese. It is possible to secure the efficiency to prevent contamination of the film by manganese, and to prevent the occurrence of chromaticity due to the excessive injection of oxidant.

1 is a system diagram showing the configuration of an oxidant injector capable of dissolving manganese in a membrane filtration water purification process according to the present invention.
FIG. 2 is a flowchart illustrating a method of injecting an oxidant capable of dissolving manganese in a membrane filtration water purification process according to the present invention.

Hereinafter, with reference to the accompanying drawings the configuration of the oxidant injector capable of dissolving manganese in the membrane filtration water treatment process according to the present invention will be described in detail.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

1 is a system diagram showing the configuration of an oxidant injector capable of dissolving manganese in a membrane filtration water purification process according to the present invention.

Referring to FIG. 1, an oxidant injector 1 capable of dissolving manganese in a membrane filtration water purification process according to the present invention includes a raw water tank 10, a first manganese measuring device S1, a TOC measuring device S2, , Oxidant contact tank 20, oxidant storage tank 30, pretreatment tank 40, separation membrane 50, treatment water tank 60, sodium hypochlorite storage tank 70, second manganese measuring instrument ( S3), the chromaticity measuring instrument S4, the discharge water tank 80, and the control part 90 are comprised.

First, the raw water tank 10 is stored in which raw water is introduced.

Then, the first manganese measuring device (S1) measures the manganese concentration of the raw water supplied to the raw water tank (10).

In addition, the TOC measuring instrument (S2) measures the total organic carbon (TOC) concentration of the raw water supplied to the raw water tank (10).

In addition, the oxidant contact tank 20 receives and stores the raw water of the raw water tank 10, contacts with the oxidant and discharges it. At this time, the first flow meter (F1) for measuring the flow rate of the raw water discharged from the raw water tank 10 to the oxidant contact tank 20 in the pipeline between the raw water tank 10 and the oxidant contact tank 20 is preferably installed. Do.

Subsequently, the oxidant storage tank 30 supplies the oxidant to the oxidant contact tank 20. At this time, the oxidizing agent is preferably sodium permanganate or potassium permanganate. In addition, the first chemical pump (P1) is installed in the conduit to pressurize and supply the oxidant discharged from the oxidant storage tank 30 to the oxidant contact tank 20, and to measure the flow rate of the oxidant of the first chemical pump (P1) The second flowmeter F2 is installed on the discharge side.

In addition, the pretreatment tank 40 performs premixing-aggregation-precipitation that is generally applied to pre-treat the raw water flowing into the separator 50 and discharge it.

In addition, the separation membrane 50 is a pressurized separation membrane 50, and the microfiltration membrane (MF), the ultrafiltration membrane (UF), the nanofiltration membrane (NF), the reverse osmosis membrane (RO), and the like are applied and discharged from the pretreatment tank 40. Filter the pretreated water.

In addition, the treated water tank 60 stores the treated water filtered and discharged from the separation membrane 50, and supplies the treated water to the backwashing water during backwashing of the separation membrane 50. At this time, between the treatment tank 60 and the separation membrane 50, a backwash pump P3 for supplying the treatment water of the treatment tank 60 to the backwash water of the separation membrane 50, and a reverse side supplied to the separation membrane 50. A third flow meter F3 for measuring the flow rate of the washing water is provided.

Subsequently, the sodium hypochlorite storage tank 70 supplies sodium hypochlorite to the oxidant contact tank 20 and the treatment water tank 60. At this time, a second chemical pump (P2) is installed on the conduit to pressurize and supply sodium hypochlorite discharged from the sodium hypochlorite storage tank 70 to the separation membrane 50 or the oxidant contact tank 20, the supply of sodium hypochlorite A fourth flow meter F4 is installed on the discharge side of the second chemical pump P2 to measure the flow rate. In addition, the first and second solenoid valves V1 and V2 are installed to selectively open and close the conduit for selectively supplying the sodium hypochlorite discharged from the sodium hypochlorite storage tank 70 to the separator 50 or the oxidant contact tank 20. do.

In addition, the second manganese measuring device S3 measures manganese concentration of the treated water discharged from the separation membrane 50 to the treated water tank 60.

In addition, the chromaticity measuring instrument S4 measures the chromaticity of the treated water discharged from the separation membrane 50 to the treated water tank 60.

In addition, the discharge water tank 80 stores the concentrated water and the backwash water discharged from the separation membrane 50.

Meanwhile, the controller 90 measures the manganese concentration and the TOC concentration of the raw water through the first manganese measuring instrument S1 and the TOC measuring instrument S2 and controls the first chemical pump P1 according to the TOC concentration to adjust the injection amount of the oxidant. The manganese concentration and chromaticity of the treated water are measured through the second manganese measuring instrument S3 and the chromaticity measuring instrument S4. Accordingly, when the membrane 50 is backwashed, the second chemical pump P2 is controlled. Supplying sodium hypochlorite to backwash the separation membrane 50, but supplying sodium hypochlorite to the separation membrane 50 by controlling the first and second solenoid valves V1 and V2 when the manganese concentration of the treated water is higher than a predetermined value. The sodium hypochlorite is supplied to the oxidant contact tank 20.

In addition, the controller 90 measures the manganese concentration and the TOC concentration of the raw water through the first manganese measuring instrument S1 and the TOC measuring instrument S2, and when the TOC concentration is less than 3.0 mg / L, 1.7 times the manganese concentration present in the raw water. When the oxidant is injected and the TOC concentration is 3.0 mg / l or more, the oxidant is injected at five times the manganese concentration, and the injection amount of the oxidant is the flow rate flowing from the raw water tank 10 into the oxidant contact tank 20. The flow rate of the oxidant is controlled by the first chemical pump (P1) in comparison to the flow rate measured by the).

In addition, the controller 90 measures the manganese concentration and chromaticity of the treated water through the second manganese measuring device S3 and the chromaticity measuring device S4 when the membrane 50 is backwashed. The concentration of sodium hypochlorite was supplied to the separation membrane 50 at a concentration of 3 to 5 mg / l using the chemical pump P2 and the third and fourth flow meters F3 and F4, and the manganese concentration of the treated water was 0.01 mg / l. In case of abnormality, the first and second solenoid valves V1 and V2 are controlled to block the sodium hypochlorite from being supplied to the backwash water, and to be injected together with the oxidant into the oxidant contact tank 20, but the manganese concentration of the treated water is 0.01. In case of more than ㎎ / ℓ and less than 5 degrees of chromaticity, the amount of oxidant injected is doubled to increase the efficiency of manganese removal, and when the concentration of manganese in the treated water is more than 0.01 mg / l and more than 5 degrees of chromaticity, the amount of oxidant is halved. By reducing the dose and doubling the amount of sodium hypochlorite Prevents chromaticity

Hereinafter, an oxidant injection method capable of dissolving manganese in a membrane filtration water purification process according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a flowchart illustrating a method of injecting an oxidant capable of dissolving manganese in a membrane filtration water purification process according to the present invention.

Referring to FIG. 2, the oxidant injecting method capable of dissolving manganese in the membrane filtration purified water treatment process according to the present invention includes a raw water measuring process (S10), an oxidant injection amount controlling process (S20), a treated water measuring process (S30), It consists of a backwash process (S40).

<< raw water measurement process-S10 >>

First, the controller 90 measures manganese concentration and TOC concentration of raw water flowing into the raw water tank through the first manganese measuring device S1 and the TOC measuring device S2.

<< oxidant injection rate control process-S20 >>

The controller 90 compares the TOC concentration of the raw water measured by the TOC measuring instrument S2 with 3.0 mg / l of the reference concentration (S21). The oxidant is injected by controlling the chemical pump P1 (S22), and when the TOC concentration is 3.0 mg / l or more, the oxidant is injected by controlling the first chemical pump P1 at 5 times the manganese concentration, but the injection amount of the oxidant is The flow rate flowing from the raw water tank 10 into the oxidant contact tank 20 is measured by the first flow meter F1 to control the flow rate of the oxidant by the first chemical pump P1 in preparation for the flow rate (S22).

<< treatment water measurement process -S30 >>

Subsequently, the control unit 90 measures manganese concentration and chromaticity of the treated water through the second manganese measuring device S3 and the chromaticity measuring device S4.

<< back washing process-S40 >>

On the other hand, when the backwash time reaches (S41), the control unit 90 supplies the treated water from the treatment tank 60 to the separation membrane 50 through the backwash pump P3 to perform backwashing (S42). When the manganese concentration measured in the treated water measuring process (S30) is compared with the reference value (0.01 mg / l) (S43), when the manganese concentration of the treated water is 0.01 mg / l or more, the first solenoid valve V1 is opened. The second solenoid valve V2 is closed to block sodium hypochlorite from being supplied to the backwash water (S44), and the oxidant contact tank 20 is injected with the oxidant, but the chromaticity is compared with the reference value (chroma 5). (S45), when the chromaticity is 5 degrees or more, the injection amount of the oxidant is reduced by half, and the injection amount of sodium hypochlorite is doubled to prevent the occurrence of chromaticity (S46).

On the contrary, when the chromaticity is less than 5 degrees, the control unit 90 increases the manganese removal efficiency by doubling the injection amount of the oxidant (S47).

On the other hand, the controller 90 compares the manganese concentration measured in the treatment water measuring step (S30) with a reference value (0.01 mg / L) (S43), when the manganese concentration of the treated water is less than 0.01 mg / L, the first solenoid valve Close (V1), open the second solenoid valve (V2) so that sodium hypochlorite is supplied to the backwash water (S48), and the second chemical pump (P2) and the third and fourth flowmeters (F3, F4) The concentration of sodium hypochlorite is supplied to the separation membrane 50 at 3 to 5 mg / l (S49).

As those skilled in the art would realize, the described embodiments may be modified in various ways, all without departing from the spirit or scope of the present invention. It is to be understood, however, that the present invention is not limited to the specific forms referred to in the description, but rather includes all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims. Should be.

10: raw water tank 20: oxidant contact tank
30: oxidant storage tank 40: pretreatment tank
50 separation membrane 60 treatment tank
70: sodium hypochlorite storage tank 80: discharge water tank
90: control unit S1, S3: first and second manganese measuring instrument
S2: TOC Meter S4: Chromaticity Meter

Claims (9)

A raw water tank in which raw water is stored;
A first manganese measuring device for measuring the manganese concentration of the raw water supplied to the raw water tank;
A TOC measuring device for measuring the total organic carbon (TOC) concentration of the raw water supplied to the raw water tank;
An oxidant contacting tank for contacting the raw water of the raw water tank with an oxidizing agent which is sodium permanganate or potassium permanganate;
An oxidant reservoir for supplying the oxidant to the oxidant contact tank;
A pretreatment tank for pretreatment of raw water discharged in contact with the oxidant in the oxidant contact tank;
A separation membrane for filtering the pretreatment water discharged from the pretreatment tank;
A treated water tank for storing the treated water discharged from the separator and supplying the treated water to backwash water during backwashing of the separator;
A sodium hypochlorite storage tank for supplying sodium hypochlorite to the oxidant contact tank and the treated water tank;
A second manganese measuring device for measuring manganese concentration of the treated water discharged from the separator to the treated water tank;
A chromaticity measuring device for measuring the chromaticity of the treated water discharged from the separator to the treated water tank;
A discharge tank for storing the concentrated water and the backwash water discharged from the separator;
A first flow meter for measuring the flow rate of the raw water discharged from the raw water tank to the oxidant contact tank;
A second flow meter for measuring the flow rate of the oxidant discharged from the oxidant reservoir;
A third flow meter for measuring the flow rate of backwash water supplied from the treated water tank to the separator;
A fourth flow meter for measuring the flow rate of the sodium hypochlorite discharged from the sodium hypochlorite storage tank;
A first chemical pump for pressurizing the oxidant discharged from the oxidant reservoir;
A second pharmaceutical pump for pressurizing said sodium hypochlorite discharged from said sodium hypochlorite storage tank;
A backwash pump for supplying the treated water of the treated water tank to the backwash water of the separator;
First and second solenoid valves configured to open and close a conduit to selectively supply the sodium hypochlorite discharged from the sodium hypochlorite storage tank to the separator or the oxidant contact tank; And
Measure the manganese concentration and TOC concentration of the raw water through the first manganese measuring instrument and the TOC measuring instrument, if the TOC concentration is less than 3.0mg / L, the oxidant is injected at 1.7 times the manganese concentration present in the raw water, the TOC concentration is 3.0mg / The oxidant is injected at 5 times the concentration of manganese, but the amount of the oxidant is injected into the oxidant contacting tank from the raw water tank by measuring the flow rate with the first flowmeter and the oxidant with the first chemical pump in comparison with the flow rate. Control the flow rate of the water, and measure the manganese concentration and chromaticity of the treated water through the second manganese meter and the chromaticity meter, thereby supplying the sodium hypochlorite to the treated water when backwashing the separator to backwash the membrane. However, if the manganese concentration of the treated water is above a certain value, the supply of the sodium hypochlorite to the separator is cut off, the hypochlorous acid or Dissolved manganese oxidant inlet device corresponds to the available volume in the membrane filtration purification process which comprises a control unit for supplying the oxidizing agent contact twos. delete delete delete The method of claim 1,
The control unit,
When backwashing, the manganese concentration and chromaticity of the treated water are measured by the second manganese measuring instrument and the chromaticity measuring instrument. When the manganese concentration and the chromaticity are less than the reference values, the sodium hypochlorite is discharged by using the second chemical pump and the third and fourth flowmeters. The concentration was supplied to the separator at 3 to 5 mg / l, and when the manganese concentration of the treated water was 0.01 mg / l or more, the first and second solenoid valves were controlled to prevent the sodium hypochlorite from being supplied to the backwash water. When the oxidant contact tank is injected together with the oxidant, the manganese concentration of the treated water is 0.01 mg / l or more and the chromaticity is less than 5 degrees. When the manganese concentration is 0.01 mg / l or more and the chromaticity is 5 degrees or more, the amount of the oxidant is reduced by half, and the amount of the sodium hypochlorite is doubled. Dissolved manganese oxidant injection device capable of corresponding in the membrane filtration water treatment process, characterized in that for preventing chromaticity caused. According to claim 1, In the membrane filtration purified water treatment process using the oxidant injection device capable of dissolving manganese dissolved in the membrane filtration water treatment process
A raw water measurement step of measuring manganese concentration and TOC concentration of raw water flowing into the raw water tank;
When the manganese concentration and TOC concentration of raw water are measured and the TOC concentration is less than 3.0 mg / l, the oxidizing agent of sodium permanganate or potassium permanganate is injected at 1.7 times the manganese concentration present in raw water, and if the TOC concentration is 3.0 mg / l or more, An oxidant injection amount control process of injecting the oxidant at a concentration of 5 times, wherein the injection amount of the oxidant is controlled in the flow rate of the oxidant relative to the flow rate flowing from the raw water tank to the oxidant contact tank;
A treated water measuring step of measuring manganese concentration and chromaticity of the treated water; And
When the membrane was backwashed, sodium hypochlorite was supplied to the treated water to backwash the membrane, but when the manganese concentration of the treated water was higher than a predetermined concentration value, the sodium hypochlorite was cut off to the separator and the sodium hypochlorite was removed. An oxidant injection method capable of coping with dissolved manganese in a membrane filtration water purification process, characterized in that the backwash process is injected into the oxidant contact bath. delete delete The method of claim 6,
The backwashing process,
When the manganese concentration and chromaticity of the treated water are measured and the manganese concentration and the chromaticity are less than the reference value, the sodium hypochlorite concentration is supplied to the separator at 3 to 5 mg / l, and the manganese concentration of the treated water is 0.01 mg / l or more. The sodium hypochlorite is blocked from being supplied to the backwash water and injected into the oxidant contact tank together with the oxidant, but when the manganese concentration of the treated water is 0.01 mg / l or more and the chromaticity is less than 5 degrees, the injection amount of the oxidant is 2 Increasing the efficiency of manganese removal by doubling, if the concentration of manganese in the treated water is 0.01mg / L or more, 5 degrees or more, the injection amount of the oxidant is cut in half, and the injection amount of sodium hypochlorite is doubled to increase the chromaticity An oxidant injection method capable of counteracting dissolved manganese in a membrane filtration water purification process, characterized by preventing generation.

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