KR20140045812A

KR20140045812A - Process for cleaning a filtration membrane and bio-fouling preventing material for the filtration membrane

Info

Publication number: KR20140045812A
Application number: KR1020120112040A
Authority: KR
Inventors: 오병수; 김민정; 유지현; 윤제용; 계정일
Original assignee: 엘지전자 주식회사
Priority date: 2012-10-09
Filing date: 2012-10-09
Publication date: 2014-04-17

Abstract

A method for cleaning a filter membrane, according to an embodiment of the present invention, includes a sterilizing step, in which a filter membrane is sterilized by a bio-fouling remover including hypochlorous acid (HClO), and succinimide. According to the method for cleaning a filter membrane, bio-fouling, generated during a water treatment filter membrane process, can be effectively controlled, and damages to the filter membrane including a polyamide-based polymer material can be minimized at the same time.

Description

TECHNICAL FOR CLEANING A FILTRATION MEMBRANE AND BIO-FOULING PREVENTING MATERIAL FOR THE FILTRATION MEMBRANE

The present invention relates to a method for cleaning a filtration membrane and a biofouling remover of the filtration membrane, which effectively removes and controls biofouling generated in a water treatment filtration membrane process, while simultaneously minimizing damage to the filtration membrane including a polyamide-based polymer material. It relates to a cleaning method and a biofouling agent of the filtration membrane.

Water treatment method using a filtration membrane is one of the widely used water treatment technology as the depletion and pollution of water resources intensify. It is widely used in water treatment, including desalination of seawater and brackish water, water purification, wastewater treatment, etc. because of its high stability and efficiency since energy efficiency and no additional chemicals are used.

However, in a water treatment method using a filtration membrane, a filtration membrane such as an osmotic membrane has a problem that a membrane fouling phenomenon occurs that contaminants adhere to the surface thereof, thereby reducing the performance of the filtration membrane. In order to solve this problem, the pretreatment process and the membrane clean-in-place (CIP) are important, which is a key factor in determining membrane performance and membrane lifetime.

The osmosis membrane is a separation membrane for separating solutions having a difference in concentration, and is a membrane used for the osmotic phenomenon in which water of a low concentration solution moves through the membrane and moves toward a high concentration solution after a certain time. The reverse osmosis phenomenon is to send water to a low concentration solution by applying an osmotic pressure or more to a high concentration solution, and the separator used at this time is a reverse osmosis membrane. Usually, the reverse osmosis membrane system is divided into water treatment, pretreatment, reverse osmosis membrane process, and post treatment.

The pretreatment process is an initial treatment of raw water before it is supplied to the reverse osmosis membrane. This process is performed to improve the quality of the raw water in the preceding stage of the reverse osmosis membrane process. Physical processing steps.

In reverse osmosis membrane processes, chlorine solutions are used as disinfectants to inactivate microorganisms, one of the major contaminants that degrade membrane performance and shorten its life. These chlorine solutions are used in the pretreatment and membrane cleaning steps. Commonly used chlorine solutions are prepared by diluting a liquid solution such as sodium hypochlorite which decomposes hypochlorous acid in water.

The microorganism is inactivated by a strong oxidizing agent such as chlorine, in which the inactivation of the microorganism means inhibiting or killing the growth of microorganisms attached to the membrane or present in the water to remove the infectivity of the microorganism and inhibit the formation of the biofilm. Chlorine disinfectants can reduce the contamination of membranes and contribute to maintaining performance and extending the lifespan by killing microorganisms by forming biofilms, reducing the permeation rate of membranes and shortening membrane lifespans and inhibiting their growth.

Meanwhile, in order to increase the salt removal rate of the reverse osmosis membrane, polyamide may be synthesized on the surface of the reverse osmosis membrane. However, polyamide has a weak property to chlorine, which is easily damaged by chlorine treatment, resulting in deterioration of the membrane performance. For this reason, in order to prevent damage to the membrane by chlorine, a large amount of reducing agent is added to the feed water of the membrane after the pretreatment step to remove residual chlorine. However, in the absence of residual disinfectants, microorganisms pass through the pretreatment process, making the reverse osmosis membrane vulnerable to biofouling. Therefore, short-term exposure to reverse osmosis membranes using alkali or complex salts other than chlorine reduces biofouling, but is not very effective.

Hypochlorous acid is a strong oxidant with economical disinfection and sterilization ability and is widely used in water treatment process for inactivation of contaminant microorganisms. Hypochlorous acid is a weak acid and exists as hypochlorous acid and hypochlorite ions depending on pH. Chlorine solutions containing hypochlorous acid are also used in various water treatment applications and in pretreatment of reverse osmosis membrane processes.

Although pretreatment using hypochlorous acid is excellent for inactivating microorganisms, the polyamide-based reverse osmosis membrane, which has been generalized, is damaged from hypochlorous acid and has a disadvantage of degrading the performance of the membrane. That is, the polyamide reverse osmosis membrane has a problem in that its structure is broken by the chlorine component and thus its performance is lost, thereby shortening the life of the membrane. In addition, a large amount of reducing agent used after the pretreatment of the water treatment system to prevent oxidation of the membrane caused by hypochlorous acid, a strong oxidizing agent, may potentially nourish the microorganisms, so it may also promote biofouling of the membrane. have.

In order to minimize the problems described above, it is necessary to develop a new membrane having excellent durability against chlorine, or to develop a new disinfectant that can be used in an existing membrane and prevents damage to the membrane.

It is an object of the present invention to effectively remove and control biofouling generated in a water treatment filtration membrane process while simultaneously minimizing damage to the filtration membrane containing a polyamide-based polymer material and a biofouling remover of the filtration membrane used therein. To provide.

In order to achieve the above object, the cleaning method of the filter membrane according to an embodiment of the present invention comprises a polyamide-based polymer material using a biofouling remover comprising hypochlorous acid (HClO), and succinimide (succinimide) And a disinfection step of disinfecting the filtration membrane.

The biofouling remover may dissolve N-chlorosuccinimide in water or an aqueous solution, and hypochlorous acid (HClO), succinimide, and their ionic forms may be present.

The filtration membrane may include any one selected from the group consisting of forward osmosis membrane, reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, and combinations thereof.

The disinfection step may be a dissolution process of dissolving any one solid N-chlorosuccinimide selected from the group consisting of powder, pellets and combinations thereof in water or an aqueous solution to prepare a biofouling remover, and the biofouling remover. It may be to pass the inlet water containing a filtration membrane, or the process of immersing the filtration membrane in the biofouling remover.

The filtration membrane may be applied to any one water treatment process selected from the group consisting of seawater desalination, brackish water desalination, water purification, sewage treatment and wastewater treatment.

The biofouling remover is injected into the feed water, and the effective chlorine concentration by N-chlorosuccinimide of the biofouling remover included in the feed water may be 100 mg / L or less.

The biofouling remover is injected into the influent, and the effective chlorine concentration by N-chlorosuccinimide of the biofouling remover included in the influent may be 100 mg / L or less.

The disinfection step includes an immersion process in which the filtration membrane is immersed in the biofouling remover, wherein the biofouling remover has an effective chlorine concentration of 5000 mg / L or less by N-Chlorosuccinimide. It may be.

The disinfecting step may include a circulating process of circulating the biofouling remover in a water treatment process such that the biofouling remover contacts the filtration membrane, and the biofouling remover is added to N-Chlorosuccinimide. By effective chlorine concentration may be less than 5000 mg / L.

The cleaning method of the filtration membrane may further include a cleaning step after the disinfection step.

The washing step may include a process of washing the filtration membrane after dipping or circulating with distilled water.

The biofouling remover of the filtration membrane according to another embodiment of the present invention is used for disinfection of the filtration membrane including the polyamide-based polymer material, and may include N-chlorosuccinimide. .

The filtration membrane may be a filtration membrane including any one selected from the group consisting of a forward osmosis membrane, a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, a microfiltration membrane, and a combination thereof.

The biofouling remover may be an effective chlorine concentration of 5000 mg / L or less by N-chlorosuccinimide (N-Chlorosuccinimide).

Biofouling remover according to another embodiment of the present invention, which is used for disinfection of the filtration membrane containing a polyamide-based polymer material, hypochlorous acid (HClO), succinimide, and ions thereof It includes an aqueous solution comprising a.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

In one embodiment, the cleaning method of the filtration membrane includes disinfecting the filtration membrane using a biofouling remover including hypochlorous acid (HClO) and succinimide and their ionic forms. The biofouling remover dissolves N-chlorosuccinimide in water or an aqueous solution to disinfect the filtration membrane using a biofouling remover including hypochlorous acid (HClO) and succinimide. Includes a disinfection step.

The biofouling remover may be in an aqueous solution state in which N-chlorosuccinimide is dissolved in water or an aqueous solution and present together in the form of hypochlorous acid (HClO) and succinimide.

The filtration membrane is meant to be applied as a filtration membrane for water treatment, and specifically, the filtration membrane may include any one selected from the group consisting of an forward osmosis membrane, a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, a microfiltration membrane, and a combination thereof. The present method is not limited thereto, and the present washing method can be applied to all filtration membranes commonly used for water treatment.

The filtration membrane includes a polyamide-based polymer material. Since the polyamide-based polymer material is vulnerable to chlorine components, when the filtration membrane is washed using a conventional chlorine disinfectant such as sodium hypochlorite, there is a problem that may damage the filtration membrane itself. However, the present invention solved this problem by allowing N-Chlorosuccinimide to be dissolved in water and aqueous solution so that the biofouling remover contains hypochlorous acid (HClO) and succinimide together. . Therefore, the method of cleaning the filtration membrane of the present invention is particularly useful for applying to a filtration membrane comprising a polyamide-based polymer material having a property that is vulnerable to chlorine components, and further to a reverse osmosis membrane containing a polyamide-based polymer material. However, the present invention is not limited to a filtration membrane or a reverse osmosis membrane including a polyamide-based polymer material, and the other filtration membranes also need to be removed or washed with a fiofouling according to the use time. Also, since the filtration membrane cleaning method of the present invention can be applied.

The biofouling remover of the present invention is used in cleaning processes to inactivate microorganisms, one of the main sources of contamination to the filtration membranes, and to remove and control biofouling. The biofouling remover is introduced to reduce the damage of the filtration membrane by sodium hypochlorite solution or the like, which is generally used as a disinfectant, and to minimize the degradation of the membrane performance due to the damage of the filtration membrane. By using N-Chlorosuccinimide, hypochlorous acid (HClO), succinimide, and their ionic forms are present in aqueous solution, and thus may serve as the biofouling remover described above. It is possible to clean the filter membrane while minimizing damage to the filter membrane comprising a.

Hypochlorite (HClO) and succinimide included in the biofouling remover in the present invention is preferably included in the biofouling remover through a process in which N-Chlorosuccinimide is dissolved in water. The present invention may be, but is not limited thereto, and may be applied to a method for allowing hypochlorite (HClO), succinimide, and ions thereof to exist simultaneously in the biofouling remover.

The disinfection step may include a dissolution process and a treatment process.

The dissolution process includes a process of preparing a biofouling remover by dissolving any one solid N-chlorosuccinimide selected from the group consisting of powder, pellets, and combinations thereof in water.

The solid N-chlorosuccinimide can be stored in powder form or solid form for easy handling, and can be expected to have an excellent biofouling removal effect or disinfection and cleaning effect. It is easy to handle and use because it can work by dissolving in water without using solvent.

The treatment may include permeating (passing) the inflow water including the biofouling remover to the filtration membrane. The biofouling remover may include an inflow of water to clean the filtration membrane while passing through the filtration membrane. In order to include the biofouling remover in the influent, N-chlorosuccinimide may be injected into the prefiltered influent in solid or aqueous solution, or may be injected into the feed water before pretreatment is performed. .

The treatment may include immersing the filtration membrane in the biofouling remover. The treatment may be performed by separating the filtration membrane or the cell from the water treatment system and immersing the biofouling remover for a predetermined time, without separating the filtration membrane or the cell from the water treatment system, and biofouling the influent of the filtration membrane itself. As a removing agent, the biofouling remover may be passed through the filtration membrane for a predetermined time.

The washing method of the filtration membrane of the present invention can be applied as long as it is a water treatment method using a filtration membrane, and specifically, it can be applied to any one water treatment process selected from the group consisting of seawater desalination, brackish water desalination, water purification, sewage treatment and wastewater treatment. Can be.

Specifically, the cleaning method of the filtration membrane is because the type of treatment is performed, the amount of N-chlorosuccinimide, hypochlorous acid (HClO) and succinimide or N- in the biofouling agent. The amount of chlorine derived from chlorosuccinimide can be controlled.

After excessive use of the biofouling remover, an appropriate amount of reducing agent may be applied, and the amount of the biofouling remover may be adjusted without using a reducing agent in order to retain trace components. This is because if the concentration of hypochlorous acid and the like in the biofouling remover is maintained at an appropriately low level, it may provide a disinfecting effect rather than cause damage to the filtration membrane.

The cleaning method of the filtration membrane is a method of injecting the biofouling remover containing hypochlorous acid (HClO) and succinimide into the influent at low concentration before or during the inflow of the pretreated water into the filtration membrane. This may inactivate the microorganisms in the influent and control biofouling in the filtration membrane. Control of biofouling of the filtration membrane has the advantage of slowing down the contamination rate of the filtration membrane and increasing the cycle time of the cleaning process (CIP).

In addition, a method of stopping water purification for a predetermined time and immersing the filtration membrane in a relatively high concentration of biofouling agent or circulating the solution may be applied. This method, as a method applicable to the CIP process using a relatively high concentration of the solution as a shocking dosing method in a short time (Shocking dosing), there is an advantage that can be disinfected with high satisfaction, but the step of washing the filter membrane with distilled water after disinfection It is preferable to carry out more, and there is a disadvantage that some amount of biofouling agent may be included in some treated water even after the water treatment system is operated normally.

For each application, it is desirable to maintain the concentrations of hypochlorous acid (HClO) and succinimide in the appropriate range.

In the cleaning method of the filtration membrane, the biofouling remover may be injected into the feed water is not pretreated, in this case N-chlorosuccinimide of the biofouling remover included in the feed water Preferred effective chlorine concentration by) may be 100 mg / L or less, 0.01 to 100 mg / L, may be 0.01 to 50 mg / L. Here, the feed water refers to inflow water that has not undergone the pretreatment process, which is the initial treatment of water treatment, and the pretreatment process, the initial treatment of the water treatment, physically removes contaminants such as organic substances through chemical treatment and filters. Processing may be included. If the contamination of the influent is severe or the degree of contamination by the microorganism is serious, the effective chlorine concentration by N-chlorosuccinimide in the feed water may exceed 100 mg / L.

The biofouling remover included in the feed water may pass through the filtration membrane while remaining in the water treatment process. The biofouling remover present in the feedwater is used to control the effective chlorine concentration by N-Chlorosuccinimide by adjusting the flow rate during treatment or by administering a reducing agent before contacting the filtration membrane. You can adjust it to an appropriate range.

In the cleaning method of the filtration membrane, the biofouling remover is injected into the influent, the preferred effective chlorine concentration by N-Chlorosuccinimide of the biofouling remover included in the influent is 100 mg / L It may be up to and 0.01 to 100 mg / L. If the contamination of the influent is severe or the degree of contamination by the microorganism is serious, the effective chlorine concentration by N-chlorosuccinimide in the feed water may exceed 100 mg / L.

The disinfection step may include an immersion process of immersing the filtration membrane in the biofouling remover, and includes a circulation process of circulating the biofouling remover in a water treatment system such that the biofouling remover contacts the filtration membrane. It can also be done. In this case, the biofouling remover N-chlorosuccinimide (N-Chlorosuccinimide) may be a preferred effective chlorine concentration may be 5000 mg / L or less, 0.01 to 5000 mg / L. When the degree of contamination caused by microorganisms is severe, the effective chlorine concentration by N-Chlorosuccinimide may exceed 5000 mg / L, but may affect membrane performance after long-term effective chlorine exposure. . At this time, the cleaning method of the filtration membrane preferably further comprises a washing step after the disinfection step, the washing step includes a step of washing the filtration membrane after dipping or circulating process with distilled water. Such a cleaning method may minimize the remaining of the biofouling remover component in the treated water when the biofouling remover is used at a high concentration.

As described above, various methods are available for cleaning the filtration membrane, and there are advantages and disadvantages, respectively. In consideration of the cleaning effect, a circulation process in which the filtration membrane is immersed in the biofouling remover or the biofouling remover is circulated in the water treatment system. Most preferably.

Biofouling remover of the filtration membrane according to another embodiment of the present invention may include N-chlorosuccinimide (N-Chlorosuccinimide), hypochlorous acid (HClO), succinimide and their ions It may be an aqueous solution containing a form.

The biofouling remover may include hypochlorous acid (HClO), succinimide, and ions thereof in the process of dissolving N-chlorosuccinimide in water.

The biofouling remover is applied for washing the filter membrane and removing and controlling the biofouling.

The filtration membrane is not particularly limited as long as it is a filtration membrane used for water treatment, as described for the cleaning method of the filtration membrane of an embodiment of the present invention, preferably can be applied to a filtration membrane containing a polyamide-based polymer material, polyamide In the case of applying to the reverse osmosis membrane containing a high-molecular polymer material, the effect of membrane damage caused by chlorine can be minimized. The biofouling remover may be an effective chlorine concentration of 5000 mg / L or less by N-Chlorosuccinimide, and may be 0.01 to 5000 mg / L. However, when the degree of contamination by the microorganism is severe, the effective chlorine concentration by N-Chlorosuccinimide may exceed 5000 mg / L, and in this case, N-chlorosuccinimide (N Effective chlorine concentration by -Chlorosuccinimide) can be appropriately adjusted by considering the effect on the membrane and contamination of microorganisms.

In addition, the specific matters such as the content of the biofouling remover, the type of filtration membrane, the method of application in the case of applying to the cleaning method of the filtration membrane and the like and the description of the cleaning method of the filtration membrane which is an embodiment of the present invention are duplicated. Omit.

If the present invention is a method for cleaning the filtration membrane or the biofouling remover of the filtration membrane, the effective chlorine concentration is maintained in the influent or the filtration membrane for a long time while minimizing damage to the filtration membrane, thereby allowing stable and continuous water treatment. In addition, N-chlorosuccinimide can store the raw material in a solid phase, which is convenient for storage and easy to utilize. First of all, if the system is operated using a filtration membrane cleaned using the biofouling remover, there is an effect of maintaining or even increasing the removal rate of the salt despite a long operation time, the permeate of the filtration membrane is maintained very stable It is possible to operate the water treatment system as well as control the biofouling.

1 is a flowchart of a water treatment system 100 using a reverse osmosis membrane to which a filtration membrane cleaning method according to an embodiment of the present invention is applied. Hereinafter, an example in which the cleaning method of the filtration membrane, which is an embodiment of the present invention, is applied to the water treatment system 100 will be described with reference to FIG. 1.

The water treatment system 100 is connected to a feed tank 1 and a feed tank 1 for supplying the inflow water 11 to the cell 5, and a temperature controller 2 for maintaining a constant temperature of the inflow water 11. And a high pressure pump 3 positioned at a portion connecting the cell 5 and the feed tank 1 for compaction to a supply amount of the inflow water 11 or a filtration membrane (not shown) existing inside the cell 5. Include. In addition, when two or three or more cells 5 are present, a pressure regulator 4 may be further included to adjust the pressure of the influent 11 supplied to each cell 5. The cell 5 separates the influent 11 into treated water 8 which has passed through the filtration membrane (permeate) and concentrated water 9 which has not flowed through the filtration membrane, and the treated water 8 has an automatic flow meter (not shown). And the flow rate is measured by the permeate water balance 7 so that the throughput can be recorded in the computer 10. The brine 9 can be returned to the feed tank 1 again (circulation system) or discharged outside the water treatment system (non-circulation system).

The cell 5 of the water treatment system 100 is equipped with a filtration membrane, the filtration membrane may be a reverse osmosis membrane. The influent 11 can be supplied to the cell 5 in a lateral flow manner to penetrate the filtration membrane, wherein the pressure applied to the filtration membrane can be regulated by the pressure regulator 4, and the regulated pressure is connected to the connected computer 10. Can be monitored.

The pressure applied to the filtration membrane may be adjusted within a range of about 200 to 800 psig depending on the use of the filtration membrane, such as seawater and brackish water. For example, when using a membrane for water, it can be set at a constant pressure condition of about 225 psig.

In the cleaning method of the filtration membrane of the present invention, the inflow water 11 of the water treatment system 100 may be injected in the process of supplying to the cell 5, specifically, to the feed tank 1, each cell 5. It may also be injected at each part that is injected or connected to it, and at a connection with the pressure regulator 4 or the high pressure pump 3 that controls the pressure. In addition, according to the cleaning method of the filtration membrane of the present invention, the filtration membrane may be separated from each cell 5, and the filtration membrane may be directly washed.

The water treatment system 100 may be operated after the compaction process of the filtration membrane using tertiary distilled water. The tertiary distilled water is supplied to the feed tank 1, and is maintained at a constant temperature, for example, by the temperature controller 2. It is delivered to each cell (5) through a high pressure pump (3) while maintaining at 25 ℃ compaction of the filtration membrane is made. The compaction process may be terminated when it is determined that the amount of permeated water is stable, and when the compaction is completed, supply water (or influent) such as seawater or brackish water, which needs treatment, may be supplied to the feed tank 1. For example, when using a reverse osmosis membrane for brackish water, 2000 mg / L of NaCl solution may be introduced to evaluate the performance of the membrane.

The performance of the filtration membrane can be evaluated by measuring the permeate amount and salt removal rate of the cell 5, and it can be evaluated that the performance of the filtration membrane is excellent when both the permeate amount and the salt removal rate are high. However, in the actual process, the higher the permeate yield, the lower the salt removal rate, and the higher the salt removal rate, the lower the permeate yield characteristics. Therefore, it is quite difficult to improve both of them, so that both of these performances are satisfactorily satisfied. The system can be operated under process conditions.

The method of cleaning the filtration membrane and the biofouling agent of the filtration membrane according to the present invention effectively control the biofouling generated in the water treatment filtration membrane process and at the same time minimize the damage of the filtration membrane to reduce the salt removal rate despite prolonged exposure to the chlorine component. This is excellent and the water treatment system can be operated with little change in the amount of permeated water.

The method of cleaning the filtration membrane of the present invention effectively controls the biofouling generated in the water treatment filtration membrane process and at the same time minimizes the damage of the filtration membrane so that the salt removal rate is excellent and the permeate change is almost changed despite the long exposure to the chlorine component. Allow the water treatment system to operate without The biofouling remover of the filtration membrane of the present invention is easy to store and well dissolved in water, and can be applied to the cleaning process of the filtration membrane without the need for a separate organic solvent. Can be minimized.

1 is a flow chart of a water treatment system using a reverse osmosis membrane to which the filtration membrane cleaning method according to an embodiment of the present invention is applied.
2 is a graph showing a change in the amount of permeated water according to the system operating time of the filtration membrane treated by Comparative Examples 1 to 4.
3 is a graph showing a change in the amount of permeated water according to the system operating time of the filtration membrane treated by Comparative Example 4 and Examples 1 to 3.
Figure 4 is a graph showing the change in the salt removal rate according to the system operating time of the filtration membrane treated by Comparative Examples 1 to 4.
5 is a graph showing a change in the salt removal rate according to the system operating time of the filtration membrane treated by Comparative Example 4 and Examples 1 to 3.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Experimental Example

Hydrolyzed polyamide-based filtration membrane (reverse osmosis membrane) of spiral wound type LFC1 (manufactured by Hydranautics Co.) was decomposed into a flat membrane in accordance with the size of the cell 5 included in the water treatment system 100 using the reverse osmosis membrane of FIG. It cut and attached to the cell 5.

All operations of the water treatment system 100 of FIG. 1 were performed by setting the temperature controller 2 and the pressure regulator 4 to 225 psig (or 15.5 bar) and 27 ± 2 ° C. The flow rate through all the cells by the flow valve 6 was adjusted to 50 ml / min.

Tertiary distilled water (Millpore SAS, Mill-Q Direct8, tap water, primary distillation, distillation using a secondary filter, and filtered distillation using a third semi-permeable membrane) in the feed tank (1) to find the equilibrium conditions. Was supplied for about 20 hours or more, and the permeate was monitored by an automatic flowmeter. When the permeate became constant, the performance evaluation of the membrane was started with NaCl 2000 mg / L solution.

The feed tank 1 was supplied with about 6 L of NaCl solution, and the permeate 8 and the concentrated water 9 were used in a circulating system in which they were returned to the feed tank 1 again. In consideration of the time taken for the NaCl solution to pass through the membrane as permeate, the volume of permeate was measured after receiving the permeate for 1 hour. The salt concentration was measured using a conductivity meter (Horiba, DS-51, 9382-10D).

< Example 1 to 3-N- Chlorosuccinimide Cleaning with>

After the initial permeation rate and the salt removal rate of the membrane, the filtration membrane (polyamide reverse osmosis membrane) was taken out of the cell (5), rinsed sufficiently with tertiary distilled water to remove the contaminants and salts, and then disinfection of the filtration membrane was started.

Disinfection of the filtration membrane was performed using a biofouling remover containing N-chlorosuccinimide solution, wherein the effective chlorine concentration by the N-chlorosuccinimide solution included in the biofouling remover was 5000 mg / L. .

Concentration of effective chlorine was measured at 530nm wavelength of DPD reagent (HACH ^® DPD free chlorine reagent) for use by spectrophotometer (HACH, DR / 2010). Since the damage to the filtration membrane was caused by the effective chlorine, the experiment was conducted based on the same effective chlorine. Steps were carried out, and each of them was referred to as Example 1, Example 2, and Example 3.

The filtration membranes of the chlorine treated Examples 1 to 3 were again rinsed in the cell 5 after being sufficiently rinsed so that residual chlorine did not remain on the surface by flowing tertiary distilled water.

After the disinfection step, the filtration membranes of Examples 1 to 3 were again mounted on the cells 5 to operate the respective water treatment systems 100. The performance of the treated membrane was evaluated in the same manner as above, considering the time until the supplied NaCl solution passed through the membrane. Membrane performance tests for about 120 hours were performed to measure the change in membrane performance over the operating hours of the system.

< Comparative Example 1 to 3- Sodium hypochlorite Cleaning with>

In the same conditions and methods as described in Example 1, the sterilization of the filtration membrane was performed using a biofouling remover comprising sodium hypochlorite solution, wherein the sodium hypochlorite solution included in the biofouling remover The effective chlorine concentration was 5000 mg / L. The disinfection step was performed while changing the time for exposing the filtration membrane to the biofouling remover to 1 hour, 2 hours, and 3 hours, and each of them was referred to as Comparative Example 1, Comparative Example 2, and Comparative Example 3.

< Comparative Example 4-No cleaning process>

Membrane performance tests were performed for about 120 hours to determine the change in membrane performance over operating time of the system, without the sterilization of the filtration membrane, under the same conditions and methods as described in Example 1.

Experiment result

Biofouling remover comprising Comparative Examples 1 to 3 in which the filtration membrane was cleaned using a biofouling remover including sodium hypochlorite, Comparative Example 4 without using the biofouling remover, and a N-chlorosuccinimide solution. 2 to 5 show the results of evaluation of the performance of the filtration membranes of Examples 1 to 3 washed with the filtration membranes.

2 is a graph showing a change in the permeated water amount according to the system operating time of the filtration membrane treated by Comparative Examples 1 to 4, Figure 3 is a system operating time of the filtration membrane treated by Comparative Example 4 and Examples 1 to 3 It is a graph showing a change in the amount of permeation according to. 4 is a graph showing a change in the salt removal rate according to the system operating time of the filtration membrane treated by Comparative Examples 1 to 4, Figure 5 is a system operating time of the filtration membrane treated by Comparative Example 4 and Examples 1 to 3 It is a graph showing the change of the salt removal rate according to.

In Fig. 2 and Fig. 4,? And solid lines represent the results of Comparative Example 4 (Control) without washing treatment, and ■ indicate the result of Comparative Example 1 (NaOCl 1 hr) washing treatment for 1 hour, and ▲ Shows the result of Comparative Example 2 (NaOCl 2 hr) which was washed for 2 hours, and ◆ shows the result of Comparative Example 3 (NaOCl 3 hr) which was washed for 3 hours. Similarly, in FIG. 3 and FIG. 5, solid lines and FIG. 5 show the results of Comparative Example 4 (Control), which was not subjected to the cleaning treatment, and ■, ▲, and ◆ represent Example 1 (NCS 1 hr) and Example 2 (NCS, respectively). 2 hr) and Example 3 (NCS 3 hr) are shown.

Under the condition that the salt removal rate is maintained, the higher the permeation rate, the better the performance due to the greater amount of water treated during the same time, and the salt removal rate means the amount of salt contained in seawater or brackish water removed by the membrane. The higher it is, the better the performance. However, the permeate amount and the salt removal rate must both be high in order to improve the performance.In the actual process, the higher the permeate amount, the lower the salt removal rate and the higher the salt removal rate. The system is operated under process conditions that satisfy both performances.

2 and 3, it can be seen that the filtration membranes of Examples 1 to 3 have a small change in the amount of permeated water with time as compared with the filtration membranes of Comparative Examples 1 to 3. The separation membranes of Examples 1 to 3 showed a rapid decrease in the amount of permeate immediately after the cleaning treatment, but gradually increased as the system operation time increased. In addition, the longer the cleaning treatment time, the higher the rate of increase of the permeate yield, and in the case of the membrane treated for 3 hours, the amount increased by about 1.8 times beyond the initial permeate yield. That is, the performance of the filtration membranes of Examples 1 to 3 showed much better performance than the filtration membranes of Comparative Examples 1 to 3, and there is no difference even when comparing Comparative Example 4 and Examples 1 to 3, which are not treated any filtration membrane After a certain time, it can be seen that the better performance.

4 and 5, it was confirmed that even when using the filter membrane of Examples 1 to 3 in the salt removal rate is much better performance. In the case of Figure 4 showing the salt removal rate by the filtration membrane of Comparative Examples 1 to 3, it was observed that the performance has already been lowered immediately after the disinfection of the filtration membrane, and then the salt removal rate gradually decreases as the operation time passes, and then treated for 3 hours. The membranes exhibited a 20% reduction in salt removal with 120 hours of operation. On the other hand, it was confirmed that the filtration membranes of Examples 1 to 3 remained almost the same for a long time of system operation, but rather exhibited higher performance than Comparative Example 4, which was no treated filtration membrane.

The filtration membranes of Comparative Examples 1 to 3 treated with sodium hypochlorite solution showed low salt removal rate despite high permeate volume, so that the amount of water to be treated increased, but not only pure water but also the salt of the influent water permeated the filtration membrane. It can be seen that this is a result of damage to the surface of the film by the disinfectant.

From the above performance evaluation results, cleaning with a biofouling remover containing N-chlorosuccinimide has a superior effect on the maintenance of the filtration membrane than using a conventional sodium hypochlorite solution as a biofouling remover. In addition, it was also confirmed that the biofouling remover containing a high concentration of N-chlorosuccinimide did not damage the filtration membrane.

As described above, the present invention provides a biofouling remover comprising an N-chlorosuccinimide solution capable of maintaining stable concentrations of effective chlorine for a longer period of time without damaging the membrane and allowing stable and continuous water treatment, and using the same as the filtration membrane. A method of washing is provided. In addition, N-chlorosuccinimide can store the raw material in a solid phase, which is convenient for storage and easy to utilize. Above all, operating the system using a filtration membrane cleaned using a biofouling remover containing N-chlorosuccinimide has the effect of maintaining or increasing the removal rate of salts despite a long operation time. The amount of permeated water is kept very stable and can be effectively used for biofouling control.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

1: feed tank 2: temperature controller
3: high pressure pump 4: pressure regulator
5: cell 6: flow valve
7: Permeate water balance 8: Permeate water (treated water)
9: concentrated water 10: computer
11: influent

Claims

And a disinfecting step of disinfecting the filtration membrane containing the polyamide-based polymer material by using a biofouling remover including hypochlorous acid (HClO), succinimide, and ionic forms thereof.

The method of claim 1,
The biofouling remover dissolves N-Chlorosuccinimide in water or an aqueous solution, so that hypochlorous acid (HClO), succinimide and their ionic forms are present. Way.

The method of claim 1,
The filtration membrane is any one selected from the group consisting of forward osmosis membrane, reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, and a combination thereof, cleaning method of the filtration membrane.

The method of claim 1,
The disinfection step,
A dissolution process for preparing a biofouling remover by dissolving any one solid N-chlorosuccinimide selected from the group consisting of powder, pellets, and combinations thereof in water or an aqueous solution, and
A process of passing the influent including the biofouling remover through a filtration membrane or immersing the filtration membrane in the biofouling remover
It comprises, the washing method of the filtration membrane.

The method of claim 1,
The filtration membrane is applied to any one water treatment process selected from the group consisting of seawater desalination, brackish water desalination, water purification, sewage treatment and wastewater treatment, filtration membrane cleaning method.

The method of claim 1,
The biofouling remover is injected into the feed water,
The effective chlorine concentration by N-Chlorosuccinimide of the biofouling remover contained in the feed water is 100 mg / L or less, the washing method of the filtration membrane.

The method of claim 1,
The biofouling remover is injected into the influent,
The effective chlorine concentration by N-chlorosuccinimide of the biofouling remover included in the influent is 100 mg / L or less, the cleaning method of the filtration membrane.

The method of claim 1,
The disinfection step includes an immersion process of immersing the filtration membrane in the biofouling remover.
The biofouling remover is an effective chlorine concentration by N-Chlorosuccinimide (N-Chlorosuccinimide) is less than 5000 mg / L, how to wash the filter membrane.

The method of claim 1,
The disinfection step includes a circulating process of circulating the biofouling remover in a water treatment process so that the biofouling remover contacts the filtration membrane.
The biofouling remover is an effective chlorine concentration by N-Chlorosuccinimide (N-Chlorosuccinimide) is less than 5000 mg / L, how to wash the filter membrane.

10. The method according to claim 8 or 9,
The cleaning method of the filtration membrane further includes a cleaning step after the disinfection step,
The washing step comprises the step of washing the filtration membrane after dipping or circulating process with distilled water, cleaning method of the filtration membrane.

A biofouling remover of the filtration membrane which disinfects the filtration membrane including hypochlorous acid (HClO), and succinimide, and comprising a polyamide-based polymer material.

A biofouling remover of the filtration membrane which comprises N-Chlorosuccinimide and disinfects the filtration membrane containing the polyamide-based polymer material.

The method of claim 11 or 12,
Wherein the filtration membrane is one that comprises any one selected from the group consisting of forward osmosis membrane, reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, and a combination thereof, biofouling remover of the filtration membrane.

The method of claim 11 or 12,
The biofouling remover is an effective chlorine concentration of 5000 mg / L or less by N-chlorosuccinimide (N-Chlorosuccinimide), biofouling remover of the filter membrane.