KR101352497B1 - Method for physical cleaning of membrane filtration system - Google Patents

Abstract

The present invention relates to a method for physically washing a membrane filtration system which can improve space utilization and economical efficiency thereof by realizing a physical washing process dispensing with a backwashing pump while inhibiting membrane fouling as the present invention conducts the physical washing of not only the upper part of a membrane module but also the lower part of the membrane module. The method for physically washing a membrane filtration system according to the present invention comprises: a first step for conducting the water washing with raw water and air washing of the lower part of the membrane module by supplying raw water and air to a first side of the membrane module; a second step for conducting the water washing with backwashing water and air washing of the lower part of the membrane module by supplying backwashing water and air to the first side of the membrane module; a third step for conducting the backwashing of the upper part of the membrane module and the air washing of the lower part of the membrane module by supplying backwashing water to a second side of the membrane module and supplying air to the first side of the membrane module; and fourth step for conducting the water washing with raw water of the lower part of the membrane module by supplying raw water to the first side of the membrane module. [Reference numerals] (10) Raw water tank; (20) Membrane module; (30) Backwashing water tank; (40) Effluent water tank; (AA) Membrane filtration water; (BB) Sodium hypochlorite storage tank; (CC) Drainage; (DD) Air discharge; (EE) Backwashing discharge

Description

Method for physical cleaning of membrane filtration system

The present invention relates to a physical cleaning method of a membrane filtration process, and more particularly, by performing a physical cleaning process not only for the upper part but also the lower part of the membrane module, to suppress membrane fouling and membrane clogging phenomenon and to not require a backwash pump. The present invention relates to a physical cleaning method of a membrane filtration process that can implement a physical cleaning process to improve space utilization and economic efficiency.

Membrane filtration can completely remove turbidity and pathogenic microorganisms, and can expect a reduction in paper area due to the compactness and modularization of the process. In addition, there is an advantage that the operation is easy to maintain by simplifying the process.

On the other hand, the formation of the membrane surface scale by organic and inorganic contaminants and the like and the reduction of the permeation performance due to the blockage of the membrane pore size are known as the biggest problems of the membrane water treatment process. In order to reduce the permeation loss caused by membrane fouling, membrane backwashing is generally performed in the middle of the membrane filtration process. An oxidizing agent such as sodium hypochlorite (NaOCl) is added to the backwashing water to improve the backwashing effect. I add it. For reference, the present applicant has previously applied for a patent on the backwashing process of the membrane filtration water treatment process (Korean Patent No. 954571).

Referring to the conventional backwashing process with reference to Figure 1, by using a backwash pump in the state of the filtration process, the backwash water of the backwash tank is selected to wash the membrane by supplying to the secondary side of the membrane module. As such, the conventional backwashing process requires a backwash pump separately from the raw water supply pump, and accordingly, a required space for the backwash pump arrangement is additionally required. In addition, according to the conventional backwashing process, the backwashing water is supplied only to the upper part of the membrane module, that is, the secondary side, so that the cleaning effect on the upper and lower parts of the membrane module and the primary side depends on air cleaning, and the surface of the membrane is cleaned and the pollutants are discharged. The efficiency is limited.

Korean Patent No. 954571

The present invention has been made to solve the above problems, by performing a physical cleaning process not only to the upper portion of the membrane module but also to the lowering of the membrane fouling and membrane blocking phenomenon and does not require a backwash pump physical cleaning process The purpose of the present invention is to provide a physical cleaning method of membrane filtration process that can improve space utilization and economic efficiency.

The physical cleaning method of the membrane filtration process according to the present invention for achieving the above object is to supply the raw water and air to the primary side of the membrane module, the first to perform the water washing and air cleaning by the raw water to the bottom of the membrane module process; A second process of supplying backwash water and air to the primary side of the membrane module to perform flushing and air cleaning by backwashing the lower part of the membrane module; A third process of supplying backwash water to the secondary side of the membrane module and supplying air to the primary side of the membrane module to perform backwashing on the upper membrane module and air cleaning on the lower membrane module; And a fourth process of supplying raw water to the primary side of the membrane module and performing water washing with the raw water on the lower portion of the membrane module.

The physical filtration method of the membrane filtration process uses a membrane filtration purified water treatment device, and the membrane filtration purified water treatment device includes a raw water-backwash water supply pump for selectively supplying raw water of a raw water tank and backwash water of a backwash water tank to a membrane module; , A raw water shutoff valve provided between the raw water tank and the raw water and the backwash water supply pump, a backwash shutoff valve provided between the backwash tank and the raw water and the backwash water supply pump, and a primary side of the raw water and the backwash water supply pump and the membrane module. Raw water and backwash water supply valves provided in the pipes between them, backwash water supply valves provided in the piping between the raw water and backwash water supply pumps and the secondary side of the membrane module, and air supply provided on one side of the primary pipe of the membrane module. It comprises a device and an air supply valve.

In the case of the first process, the backwash water shutoff valve and the backwash water supply valve are shut off, and the raw water shutoff valve, the raw water backwash water supply valve, and the air supply valve are kept open. In the second process, the raw water shutoff valve and the backwash water supply valve are kept in a blocked state, and the backwash water shutoff valve, the raw water-backwash water supply valve, and the air supply valve are kept open. In the third process, the raw water shutoff valve and the raw water-reverse water supply valve remain blocked, and the backwash water shutoff valve, the reverse wash water supply valve, and the air supply valve remain open. In the fourth process, the raw water shutoff valve and the raw water-backwash water supply valve remain open, and the backwash water shutoff valve and the backwash water supply valve remain blocked.

A sodium hypochlorite injection pump is further provided in the pipe between the backwash tank and the backwash shutoff valve to supply sodium hypochlorite to the backwash water supplied to the membrane module. In addition, the first to fourth processes are performed in a state where the filtration process using the membrane module is completed.

The physical cleaning method of the membrane filtration process according to the present invention comprises the first step of supplying raw water and air to the primary side of the membrane module, the washing and air cleaning by the raw water to the lower portion of the membrane module; A second process of supplying backwash water and air to the primary side of the membrane module to perform flushing and air cleaning by backwashing the lower part of the membrane module; And supplying backwash water to the secondary side of the membrane module and supplying air to the primary side of the membrane module, thereby performing a third process of backwashing the upper membrane module and performing air cleaning on the lower membrane module. After the third process, a drainage process for discharging raw water, backwash water and air in the membrane module, a water supply process for supplying raw water in the membrane module, and a filtration process for raw water using the membrane module are sequentially performed. It is done.

The physical cleaning method of the membrane filtration process according to the present invention has the following effects.

By omitting the backwash pump, the space utilization and economic efficiency of the device are improved, and the membrane contamination and membrane clogging phenomenon are carried out by performing physical cleaning not only on the primary and secondary sides of the membrane module but also on the upper and lower portions of the membrane module. Can be suppressed.

1 is a block diagram of a membrane filtration water treatment apparatus according to the prior art.
Figure 2 is a block diagram of a membrane filtration water treatment apparatus according to an embodiment of the present invention.
3 is a reference diagram showing a physical cleaning method in the low turbidity mode.
4 is a reference diagram showing a physical cleaning method in the high turbidity mode.

The present invention proceeds the physical washing process for the upper and lower parts of the membrane module using a raw water supply pump without a separate backwash pump, and in detail, the backwashing using the backwashing water for the upper part of the membrane module and the lower part of the membrane module. Regarding the washing and air washing using raw water is characterized in that. In addition, the present invention can effectively control the operation of the device by applying a physical cleaning process in accordance with the turbidity of the raw water.

Hereinafter, a physical cleaning method of a membrane filtration process according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Prior to explaining the physical cleaning method of the membrane filtration process according to the present invention, the configuration of the membrane filtration water treatment apparatus to which the present invention is applied is as follows.

Referring to FIG. 2, the membrane filtration water purification apparatus to which the present invention is applied includes a raw water tank 10, a membrane module 20, and a backwash tank 30. Raw water of the raw water tank 10 is filtered by the membrane module 20, the filtered water of the membrane module 20 is supplied to the backwash tank (30). The filtered water stored in the backwash tank 30 is supplied to the backwash water of the membrane module 20, which will be described in detail later.

On the other hand, the raw water of the raw water tank 10 and the filtered water of the backwash tank 30 are selectively supplied to the membrane module 20 by the raw water-backwash water supply pump 203, for the selective supply of raw water or backwash water. A raw water shutoff valve 201 is provided between the water tank 10 and the raw water-backwash water supply pump 203, and a backwash water shutoff valve 202 is provided between the backwash tank 30 and the raw water-backwash water supply pump 203. Is provided. That is, in the state in which the raw water shutoff valve 201 is opened and the backwash water shutoff valve 202 is closed, the raw water is supplied through the raw water-backwash water supply pump 203, on the contrary, the backwash water shutoff valve 202 is opened and the raw water shutoff valve In the state in which 201 is closed, the backwash water is supplied through the raw water-backwash water supply pump 203. In addition, the sodium hypochlorite injection pump 209 is provided in the piping between the backwash tank 30 and the backwash shutoff valve 202 to supply sodium hypochlorite to the backwash water supplied to the membrane module 20. . The raw water-backwash water supply pump 203 is a configuration corresponding to a conventional raw water supply pump, and in addition to the supply of raw water, which is a basic role, it is possible to supply backwash water.

In the physical washing method of the present invention, raw water is supplied to the primary side of the membrane module 20, that is, the lower side of the membrane module 20, and the backwash water is supplied to the primary side or the secondary side of the membrane module 20 (membrane module ( 20) is optionally supplied. To this end, a pipe between the raw water-backwash water supply pump 203 and the primary side of the membrane module 20 is provided with a raw water-backwash water supply valve 204, and the raw water-backwash water supply pump 203 and the membrane module. A backwash water supply valve 205 is provided in the piping between the secondary sides of the 20.

Through such a configuration, it is possible to selectively supply the raw water and the backwash water to the primary side or the secondary side of the membrane module 20 using the raw water-reverse washing water supply pump 203, and based on this, an embodiment of the present invention The physical filtration process of the membrane filtration process is possible.

Meanwhile, an air supply device and an air supply valve 206 are provided at one side of the primary pipe of the membrane module 20 to selectively supply air to the lower portion of the membrane module 20. In addition, one side of the membrane module 20 is provided with a physical wash discharge valve 207 and a drain valve 208, and the raw water, backwash water and air used in the physical washing are the physical wash discharge valve 207 and the drain valve. It is discharged to the discharge tank 40 through 208.

In addition, a filtrate valve 210 is provided between the membrane module 20 and the backwash tank 30, and the supply of the filtrate produced by the membrane module 20 is selectively controlled by the filtrate valve 210. . In addition, a bleed valve 211 is further provided for removing the initial pollutant present in the pipe between the membrane module 20 and the backwash bath 30.

In the above, the configuration of the membrane filtration water treatment apparatus to which the present invention is applied has been described. Operation of the membrane filtration purified water treatment device is largely performed by 1) water supply, 2) filtration, 3) physical washing, and 4) drainage, wherein 1) water supply is a process of supplying raw water to the membrane module 20. When the turbidity of the raw water is low, it can be omitted, the 2) filtration refers to the filtration process of the raw water by the membrane module 20, the 3) physical washing is referred to a physical washing method according to an embodiment of the present invention And, 4) the drainage is a process of discharging the water in the membrane module 20 to the outside is omitted in the low turbidity mode of the low turbidity of the raw water.

3) during the operation of the membrane filtration purified water treatment device, that is, the physical washing method of the membrane filtration process according to an embodiment of the present invention will be described in detail.

When the filtration process by the membrane module 20 is completed, the physical washing process for the membrane module 20 is performed, the physical washing method according to the present invention is <primary side water washing and offensive process (first process)>, <The primary backwashing and offensive (second process)>, <secondary backwashing and offensive process (third process)>, and the primary raw water washing process (fourth process).

Through the first to the fourth process it is possible to physically wash the primary side, secondary side and the upper and lower portions of the membrane module 20, which does not require a separate backwash pump, which is a feature of the present invention, Detailed operations of the first to fourth processes are as follows.

First, the first process, that is, <primary side water washing and offensive process> is a process of physically washing the primary side and the lower side of the membrane module 20 using raw water and air (see 1 in FIG. 2). To this end, the backwash water shutoff valve 202 and the backwash water supply valve 205 are shut off and the sodium hypochlorite injection pump 209 is also not operated, while the raw water shutoff valve 201 and the raw water-reverse water supply valve 205 are not operated. ) And the air supply valve remain open.

The second process, that is, <primary side backwash and flush process> is a process of physically washing the primary side and the lower part of the membrane module 20 using backwash and air (see ② in FIG. 2). In order to supply the backwash water to the membrane module 20 primary side, the backwash water shutoff valve 202 and the raw water-backwash water supply valve 204 remain open, and the sodium hypochlorite injection pump 209 and the raw water- The backwash water supply pump 203 also operates, and the raw water shutoff valve 201 and the backwash water supply valve 205 remain blocked. In addition, the air injection pump and the air supply valve 206 to maintain the operating state for the air cleaning.

The third process, <secondary backwashing backwashing and offensive process> supplies backwashing water to the secondary side of the membrane module 20 to backwash the secondary side and the upper portion of the membrane module 20 and at the same time the membrane module 20 ) Is a process of air cleaning the primary side and the lower side of the membrane module 20 by supplying air to the primary side of (). The backwash water shutoff valve 202 and the backwash water supply valve 205 are kept open for supply of the backwash water to the secondary side of the membrane module 20, and the sodium hypochlorite injection pump 209 and the raw water-backwash water The supply pump 203 also operates, and the raw water shutoff valve 201 and the raw water-reverse water supply valve 205 remain blocked. In addition, the air injection pump and the air supply valve 206 to maintain the operating state for cleaning the air under the membrane module (20).

The fourth process, that is, <primary water washing process> is a process of physically washing the membrane module 20 with raw water by supplying raw water to the primary side of the membrane module 20 (see ④ in FIG. 2). To this end, the raw water shutoff valve 201 and the raw water-reverse water supply valve 204 remain open, and the backwash water shutoff valve 202 and the backwash water supply valve 205 remain blocked.

In the first to fourth processes, the physical wash discharge valve 207 is opened to discharge the raw water, the backwash water and the air in the membrane module 20, and the filtrate valve 210 Stay closed during the process.

On the other hand, the physical cleaning method according to the present invention can be selectively changed and applied according to the turbidity of the raw water as described above. When the turbidity of the raw water is relatively low, it is operated in the low turbidity mode (see FIG. 3), and when the turbidity of the raw water is relatively high, it is operated in the high turbidity mode (see FIG. 4). Turbidity which is the standard of low turbidity mode and high turbidity mode may vary according to various situations, but 10-15 NTU can be set as the reference turbidity. In the case of 10-50 NTU, high turbidity mode can be applied.

In the case of the low turbidity mode, the above-described first to fourth processes are sequentially applied, and the drainage process and the water supply process are omitted. On the other hand, in the high turbidity mode, the drainage process is required for the discharge of contaminants in the membrane module 20, and accordingly, the water supply process is added. As the water supply process is added, the fourth process, that is, <primary water washing process> is omitted.

In the high turbidity mode operation, the drain valve 208 is additionally kept open in addition to the physical wash discharge valve 207 during the drainage process, and the device operation in the water supply process is performed in the fourth process, that is, the <primary water washing process>. The same applies to the device operation of. In addition, in the high turbidity mode, the bleed valve 211 is kept open to remove initial contaminants in the secondary pipe of the membrane module 20 in the third process, that is, the secondary backwash backwash and offensive process. do.

10: raw water tank 20: membrane module
30: backwash tank 40: discharge tank
50: sodium hypochlorite storage tank
201: Raw water shutoff valve 202: Backwash water shutoff valve
203: raw water-backwash water supply pump 204: raw water-backwash water supply valve
205: backwash water supply valve 206: air supply valve
207: physical cleaning discharge valve 208: drain valve
209 sodium hypochlorite infusion pump
210: filtered water valve 211: bleed valve

Claims (11)

A first process of supplying raw water and air to the primary side of the membrane module to perform washing with water and air washing with the raw water to the lower portion of the membrane module;
A second process of supplying backwash water and air to the primary side of the membrane module to perform flushing and air cleaning by backwashing the lower part of the membrane module;
A third process of supplying backwash water to the secondary side of the membrane module and supplying air to the primary side of the membrane module to perform backwashing on the upper membrane module and air cleaning on the lower membrane module; And
And a fourth step of supplying the raw water to the primary side of the membrane module and performing water washing with the raw water on the lower part of the membrane module.
According to claim 1, The physical filtration method of the membrane filtration process using a membrane filtration water treatment device, the membrane filtration water treatment device,
A raw water-backwash water supply pump for selectively supplying raw water of a raw water tank and backwash water of a backwash tank to a membrane module;
A raw water shutoff valve provided between the raw water tank and the raw water-reverse water supply pump,
A backwash shutoff valve provided between the backwash tank and the raw water-backwash water supply pump,
A raw water-backwash water supply valve provided in a pipe between the raw water-backwash water supply pump and the primary side of the membrane module;
A backwash water supply valve provided in a pipe between the raw water and the backwash water supply pump and the secondary side of the membrane module;
Physical cleaning method of the membrane filtration process comprising an air supply device and an air supply valve provided on one side of the primary pipe of the membrane module.
The method of claim 2, wherein in the case of the first process,
The backwash water shutoff valve and the backwash water supply valve are shut off,
The raw water shutoff valve, the raw water backwash water supply valve, and the air supply valve are kept open.
The method of claim 2, wherein in the case of the second process,
The raw water shutoff valve and the backwash water supply valve remain blocked.
A backwash shutoff valve, a raw water-backwash water supply valve, and an air supply valve are kept open.

The method of claim 2, wherein in the third process,
The raw water shutoff valve and the raw water-reverse water supply valve remain blocked.
A backwash shutoff valve, a backwash water supply valve, and an air supply valve are maintained in an open state.
The method of claim 2, wherein in the fourth process, the raw water shutoff valve and the raw water-reverse water supply valve are kept open, and the backwash block and the backwash water supply valve are kept blocked. Physical cleaning method of membrane filtration process.
The physics of the membrane filtration process according to claim 2, wherein a sodium hypochlorite injection pump is further provided in a pipe between the backwash tank and the backwash shutoff valve to supply sodium hypochlorite to the backwash water supplied to the membrane module. How to wash.
The method of claim 1, wherein the first to fourth processes are performed while the filtration process using the membrane module is completed.
A first process of supplying raw water and air to the primary side of the membrane module to perform washing with water and air washing with the raw water to the lower portion of the membrane module;
A second process of supplying backwash water and air to the primary side of the membrane module to perform flushing and air cleaning by backwashing the lower part of the membrane module; And
And a third process of supplying backwash water to the secondary side of the membrane module and supplying air to the primary side of the membrane module to backwash the upper portion of the membrane module and to clean the air to the lower side of the membrane module.
After the third process,
Physical washing of the membrane filtration process, characterized in that the drainage process of discharging raw water, backwash water and air in the membrane module, the water supply process of supplying raw water into the membrane module, and the filtration process of raw water using the membrane module are sequentially performed. Way.
The method of claim 9, wherein the physical filtration method of the membrane filtration process uses a membrane filtration water treatment device, the membrane filtration water treatment device,
A raw water-backwash water supply pump for selectively supplying raw water of a raw water tank and backwash water of a backwash tank to a membrane module;
A raw water shutoff valve provided between the raw water tank and the raw water-reverse water supply pump,
A backwash shutoff valve provided between the backwash tank and the raw water-backwash water supply pump,
A raw water-backwash water supply valve provided in a pipe between the raw water-backwash water supply pump and the primary side of the membrane module;
A backwash water supply valve provided in a pipe between the raw water and the backwash water supply pump and the secondary side of the membrane module;
Air supply device, air supply valve and one side of the primary pipe of the membrane module
The physical cleaning method of the membrane filtration process provided on one side of the membrane module comprising a physical wash discharge valve and a drain valve for discharging raw water, backwash water and air used for physical cleaning.
The method of claim 10, wherein in the first process, the backwash water shutoff valve and the backwash water supply valve are shut off, and the raw water shutoff valve, the raw water backwash water supply valve, and the air supply valve are kept open.
In the second process, the raw water shutoff valve and the backwash water supply valve are kept in a blocked state, and the backwash water shutoff valve, the raw water-backwash water supply valve, and the air supply valve are kept open.
In the third process, the raw water shutoff valve and the raw water-backwash water supply valve remain blocked, and the backwash water shutoff valve, the reverse wash water supply valve, and the air supply valve remain open.
In the case of the drainage process, the physical cleaning method of the membrane filtration process, characterized in that to maintain the physical washing discharge valve and the drain valve open.

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