KR102024927B1 - Backwashing system with concentrated brine and backwashing method therewith - Google Patents

Abstract

The present invention relates to a device capable of performing backwashing of a filtration membrane module which is a pretreatment process using a reverse osmosis membrane concentrated water containing a high concentration of salts, and a method of backwashing using such a device, and a filtration membrane module such as MF or UF and a reverse osmosis membrane. In a system in which modules are connected in series to purify seawater or wastewater, a device capable of backwashing the filtration membrane module using concentrated water containing a high concentration of salt discharged from the reverse osmosis membrane module and a backwashing method using the same The present invention proposes a method for using the concentrated water containing high concentration of salts discharged during the operation of the reverse osmosis membrane module for backwashing the filtration membrane module, thereby effectively sterilizing and disinfecting the filtration membrane module as well as more economical and effective backwashing. There are advantages to it.

Description

Backwashing system with concentrated brine and backwashing method therewith}

The present invention relates to a device capable of performing backwashing of a filtration membrane module which is a pretreatment process using a reverse osmosis membrane concentrated water containing a high concentration of salts, and more particularly, to a backwashing method using such a device. In a system in which the same filtration membrane module and the reverse osmosis membrane module are connected in series to purify seawater or wastewater, a device capable of backwashing the filtration membrane module using concentrated water containing a high concentration of salt discharged from the reverse osmosis membrane module. And a backwashing method using the same.

Recently, groundwater or rivers are seriously contaminated by heavy metals, pathogenic microorganisms, trace organic toxic substances, etc., and it is very important to secure the safety of drinking water. There is a growing interest in water treatment apparatuses and water treatment methods.

Common water treatment methods include chlorine treatment, ozone treatment, membrane filtration, and the like, and the water treatment system mainly operates by partially modifying these treatment methods or installing two or more treatment methods step by step.

However, the conventional chlorine treatment method has a problem that trihalomethane is generated as a by-product when chlorine is disinfected, and the ozone treatment method has a disadvantage in that ozone selectively treats organic toxic substances.

Water purification method by membrane filtration can reduce the scale of the water purification apparatus by filtering and removing contaminants contained in the raw water using a membrane (membrane), as shown in the Patent Publication No. 2003-0079479 Although there is an advantage, the blockage of the filtration membrane due to contaminants causes the frequent replacement of the filtration membrane, resulting in excessive operating costs.

In order to solve the disadvantage of the membrane filtration method of water purification method, a separate backwash water storage tank, a pump and a backwash system for backwashing the filtration membrane are constructed and applied.

However, such a conventional backwash system has a high cost investment in construction, and there is still a problem that requires additional operating costs according to the operation of the backwash pump.

Publication No. 2003-0079479 (published: October 10, 2003)

The present invention is a conventional water treatment apparatus or water treatment method through membrane filtration, by using a concentrated water containing a high concentration of salt discharged through the membrane filtration to backwash the filtration membrane module included in the membrane filtration process The aim is to improve sterilization and bactericidal function, as well as more economical and effective backwashing.

In addition, by using concentrated water containing high concentrations of salt as backwash water, it is possible to produce safer drinking water or fresh water by not using additional acid or chemicals such as NaOCl, and further separation or washing of chemicals. It is intended to provide a method for treating integers that is not necessary.

The reverse washing apparatus using the reverse osmosis membrane concentrated water according to one embodiment of the present invention, the filtration membrane module is supplied with raw water; A first storage tank for storing pretreated water through the filtration membrane module; A reverse osmosis membrane module to which the treated water of the first reservoir is supplied; A second storage tank storing concentrated water discharged from the reverse osmosis membrane module; And a backwash pump for supplying the concentrated water stored in the second reservoir to the backwash water of the filtration membrane module.

The filtration membrane module is preferably a microfiltration membrane or an ultrafiltration module, and a pump for transferring the treated water is installed between the first reservoir and the reverse osmosis membrane module.

Preferably, the second reservoir uses a backwash pressure vessel or a pressure tank, and more preferably, the salt concentration of the concentrated water supplied to the backwash water is about 50,000 to 70,000 ppm.

In addition, the second reservoir may further include a salt supply unit for supplying additional salts to increase the salt concentration of the stored concentrated water, and the salts supplied through the salt supply unit may include NaCl, CaCl 2 or It is preferred that it is KCl.

In addition, the second reservoir may further include a salt measuring device capable of measuring the salt concentration of the stored concentrated water, and the salt measuring device may be linked with a controller to control the salt concentration of the second storage tank. Do.

The concentrated water supplied to the backwash water is subjected to the backwash process of the filtration membrane module, at least a part of which is supplied to the drying unit, dried with the salt, and then transferred to the salt supply unit, and a part of the remaining backwash water is returned to the second storage tank. Can be.

When the salt concentration of the second storage tank measured by the salt meter is less than the reference concentration of about 50,000 ~ 70,000ppm additional salt may be supplied through the salt supply unit, if the salt is greater than about 50,000 ~ 70,000ppm salt osmosis It is preferred that a portion of the claim, the production water produced in the membrane module, is fed to the second reservoir to maintain the proper salt concentration.

In addition, the concentrated water recovered by the second storage tank may be passed through a plasma treatment tank including a plasma electrode for water treatment, which plasma treatment tank has an inlet for introducing the concentrated water and an outlet for discharging the concentrated plasma treated water. Reactor; A ground electrode provided at one side of the reactor; And a plasma electrode module provided at one side of the reactor and generating plasma, wherein the plasma electrode module comprises: a tungsten substrate having a plurality of holes formed therein; A ceramic layer surrounding the outer circumference of the tungsten base except for the hole; And a plasma electrode positioned inside the hole and having a multi-stage structure in which a ground part 33, a fixing part 32, and a discharge part 31 are stacked in this order. The ground part 33 Is in contact with the tungsten substrate, characterized in that the plasma is generated in the discharge portion (31).

In the reactor, the ground electrode and the plasma electrode module may be installed to face each other, it is also possible to further include a distance adjusting unit for adjusting the distance between the ground electrode and the plasma electrode module in the reactor.

It is preferable that the ground electrode has a plate shape, and the ground part 33, the fixing part 32, and the discharge part 31 are more preferably an integral structure made of the same material having corrosion resistance.

In addition, it is preferable that the ratio of the diameters of the ground portion 33, the fixing portion 32 and the discharge portion 31 is 7-8: 4-6: 1, and the ratio of the height is 1-2-2: 1: 1. However, the unitary structure is more preferably made of SUS material having corrosion resistance.

Another embodiment of the present invention includes a reverse washing method using a reverse osmosis membrane concentrated water, comprising: supplying raw water to the filtration membrane module; Storing the pre-treated water through the filtration membrane module in a first reservoir; Supplying the treated water stored in the first reservoir to the reverse osmosis membrane module; Storing the concentrated water discharged from the reverse osmosis membrane module in a second storage tank; And a backwashing supplying step of supplying the concentrated water stored in the second storage tank to the backwashing water of the filtration membrane module.

The filtration membrane module includes a microfiltration membrane or an ultrafiltration module, and the treated water stored in the first reservoir is preferably supplied to the reverse osmosis membrane module by a pump.

The salt concentration of the concentrated water supplied to the backwash water is preferably about 50,000 to 70,000 ppm, and the salts further supplied in the salt supply step are more preferably NaCl, CaCl 2 or KCl.

Measuring the salt concentration of the stored concentrated water between the step of storing the concentrated water in a second reservoir and a backwash feed step; And a salt supply step of supplying additional salts through the salt supply unit when the salt concentration of the stored concentrated water is lower than about 50,000 to 70,000 ppm. After the backwashing supply step, the filter membrane module may be reversed. Washed concentrated water preferably further comprises the step of being supplied to a drying unit or a second reservoir.

The drying unit may dry the concentrated water obtained by backwashing the filtration membrane module to form salts, and the salts formed in the drying unit are supplied to the salt supply unit.

In addition, the step of measuring the salt concentration of the stored concentrated water between the step of storing the concentrated water in the second reservoir and backwashing supply step; And when the salt concentration of the stored concentrated water is higher than about 50,000 to 70,000 ppm, a fresh water supplying step of supplying a part of the production water discharged from the reverse osmosis membrane module to a second storage tank may be further included. After the step, a plasma treatment step of plasma-processing the concentrated water after being used as the backwash water, through a plasma treatment tank containing a plasma treatment for water treatment; may further include.

The purified water treatment device or the purified water treatment method according to the present invention uses not only more economical and effective backwashing but also a filtration membrane by using concentrated water containing a high concentration of salt discharged during the operation of the reverse osmosis membrane module for backwashing the filtration membrane module. There is an advantage that can effectively sterilize and disinfect the module.

In addition, by using concentrated water containing high concentrations of salt as backwash water, it is possible to produce safer drinking water or fresh water by not using additional acid or chemicals such as NaOCl, and further separation of chemicals, There is no need for cleaning.

In addition, the effects of the present invention are not limited to the above-mentioned effects, and other effects, which are not mentioned above, may be clearly understood by those skilled in the art from description of specific contents for carrying out the following invention. will be.

1 is a schematic diagram schematically showing a conventional water treatment system.
2 is a schematic diagram showing a water treatment system according to the present invention.
3 is a comparison test result between a conventional backwashing method and a backwashing method according to an embodiment of the present invention.
Figure 4 is a schematic diagram showing a water treatment system according to another embodiment of the present invention further includes a plasma treatment tank.
5 and 6 schematically show a specific form of the plasma processing tank used in another embodiment of the present invention.
7 schematically illustrates a plasma nozzle used in a plasma processing tank.
8 schematically shows a plasma electrode module including a plasma nozzle.
9 and 10 schematically show a form in which a plurality of plasma processing tanks are arranged.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

Also, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in the case of conflict, the specification including definitions The description of will prevail.

In the drawings, parts irrelevant to the description are omitted to clearly describe the proposed invention, and like reference numerals designate like parts throughout the specification. In addition, when a part "contains" a certain component, this means that the component may further include other components, without excluding other components, unless specifically stated otherwise. In addition, the "unit" described in the specification means one unit or block that performs a specific function.

In each step, an identification code (first, second, etc.) is used for convenience of description, and the identification code does not describe the order of each step, and each step does not explicitly describe a specific order in context. It may be carried out in a different order than described above. That is, each step may be performed in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

Figure 1 is a schematic diagram showing a simplified water treatment system using a conventional membrane separation module.

As shown in FIG. 1, raw water such as seawater or sewage, wastewater, etc., is supplied to the filtration membrane module 10 and subjected to a pretreatment process, and then collected in the first storage tank 20, thus collected in the first storage tank 20. The water to be treated is again supplied to the reverse osmosis membrane module 40 through the pump 30.

By passing through the filtration membrane module 10 and the reverse osmosis membrane module 40 in turn, raw water containing contaminants such as various organic or inorganic substances is finally concentrated brine containing clean product water and high concentration of salt (RO Brine). In the form of a) is separated from the reverse osmosis membrane module 40 is discharged respectively.

In this case, a microfiltration membrane or an ultrafiltration membrane is used for the filtration membrane module corresponding to the pretreatment step of raw water. This increases the pressure difference (ΔP).

 Therefore, it is essential to periodically wash the membrane surface included in the filtration membrane module 10, by supplying a portion of the water to be treated in the first reservoir through the pump 25 to the back washing process, It is used to clean the filtration membrane module 10. In this case, in order to simultaneously perform effective removal of various microorganisms or bacteria present in the filtration membrane module 10, various chemical substances such as HCl and / or NaOCl may be supplied together with backwash water, thereby achieving a sterilization or disinfection effect.

However, by using a portion of the water to be obtained through the filtration membrane module 10 in the backwashing process, the amount of the produced water finally obtained through the reverse osmosis membrane module 20 is reduced, and various chemicals In addition to the additional backwashing process, additional processing time is required to flush out these chemicals, and there are problems such as the cost of discarding the backwash water discharged during the backwashing process. .

In the present invention, in order to solve the problems of the prior art, as shown in Figure 2, after storing the high concentration of concentrated water discharged separated from the fresh water produced in the reverse osmosis membrane module 40 in the second storage tank (50), This is characterized in that used as a backwash water in the backwashing process of the filtration membrane module (10).

That is, in the conventional conventional technology, the concentrated water of the reverse osmosis membrane module 40 discharged as waste is separately stored, and used as the backwash water in the reverse washing process of the filtration membrane module 10, and then recovered again to recover the second storage tank 50. This allows the high concentration of concentrated water discharged from the water treatment system using the membrane separation module to be recycled and the final amount of fresh water produced by not using the treated water stored in the existing primary reservoir. There is an effect that can be increased.

2 will be described in more detail as a feature of the present invention.

Influent water such as seawater, sewage or wastewater is first processed through the filtration membrane module 10 and stored in the first storage tank 20. Thereafter, the pump 30 is supplied to the reverse osmosis membrane module 40 to discharge fresh water, which is the final production water, to the permeate, and the concentrated water concentrated to a high concentration is discharged to the retentate.

The concentrated water discharged in this way is stored separately in the second storage tank 50, and the second storage tank is equipped with a salt measuring device 70 capable of measuring the concentration of salt, and measuring the salt concentration of the stored concentrated water as a result. May be transmitted to the control unit 101.

In addition, the second reservoir may be further provided with a salt supply unit 90, the concentration of the salt contained in the concentrated water measured by the salt measuring device 70 installed in the second reservoir is about 50,000 ~ 70,000 When the concentration is lower than ppm, the salt may be additionally supplied through the salt supply unit 90 to prepare concentrated water having a high salt concentration.

The kind of the salt supplied through the salt supply unit 90 is not particularly limited so that the concentrated water can maintain a high salt concentration, but NaCl, CaCl 2 or KCl is preferably used.

Concentrated water containing a high concentration of salt may be supplied to the backwashing water at the time of back washing of the filtration membrane module 10 through the pump 60, and the concentrated water containing such a high concentration of salt may be supplied to the backwashing process of the filtration membrane module. In addition to the physical backwash effect of simply removing the cake layer formed on the surface of the membrane, there is a biodegradable bactericidal or bactericidal effect by the high concentration of salt contained in the concentrated water.

That is, microorganisms, bacteria, and the like, which are biological contaminants present on the membrane surface of the microfiltration membrane (Microfiltration, MF) module or ultrafiltration membrane (Ultrafiltration, UF) module constituting the filtration membrane module 10 without separately disassembling the membrane module. It can be effectively sterilized or removed, there is an advantage that does not use the acid (for example, HCl, etc.) or chemicals (for example, NaOCl, etc.) that has been included in the conventional conventional backwash water.

Thus, the concentrated water of high concentration used in the back washing process of the filtration membrane module may be recovered to the second storage tank 50, some of which may be supplied to the drying unit (80).

The drying unit 80 may recover the salts by drying the concentrated water of high concentration, and the recovered salts may be used to adjust the salt concentration in the second storage tank 50 through the salt supply unit 90 mentioned above. Can be used for the process.

That is, when the salt concentration in the second reservoir 50 is measured by the salt measuring device 70 lower than the reference concentration (for example, about 50,000 ~ 70,000ppm), the salt supply unit 90 through the control unit 101 Additional salts are supplied and controlled to maintain a constant reference concentration.

On the contrary, when the salt concentration in the second reservoir 50 is higher than the reference concentration, by supplying a portion of the fresh water produced through the reverse osmosis membrane module 40 to the second reservoir 50 (not shown in the drawing). It is also possible to keep the concentration constant.

The reason for maintaining the salt concentration range in the second storage tank 50 at about 50,000 to 70,000 ppm level is that when the salt concentration is lower than this, the sterilization or bactericidal effect by the high concentration of salt is not sufficient. This is because a high concentration of salt dissolved in water acts as a contaminant on the surface of the filter membrane during the backwashing process, which may shorten the life of the MF or UF filter membrane included in the filter membrane module.

Figure 4 is a schematic view showing a backwashing apparatus using a reverse osmosis membrane concentrated water according to another embodiment of the present invention. Referring to the difference compared to the embodiment of the present invention described above, in the case of the backwashing apparatus using the reverse osmosis membrane concentrated water shown in Figure 2, so that the concentrated water used as the backwash water to pass through the plasma treatment tank 100 In addition, the plasma processing tank 100 is characterized in that it is further included.

The plasma processing tank 100 includes a reactor 110 including an inlet 111 through which concentrated water used as backwashed water, which is treated water, and an outlet 112 through which backwashed water, which is plasma treated water, are discharged, is discharged; A ground electrode 120 provided at one side of the reactor 110; And a plasma electrode 130 provided at one side of the reactor 110 and generating plasma, and present in the concentrated water used for backwashing, which is water to be treated through plasma underwater discharge using the plasma electrode 130. Has the effect of decomposing or removing organic matter and microorganisms.

Conventionally, bio-fouling formed by organic materials is suppressed by injecting chlorine before pretreatment of treated water such as seawater, but problems such as corrosion occur due to excessive injection of chlorine. By replacing the chlorine injection method with a plasma method, by effectively removing organic matter and microorganisms, there is an advantage that does not cause a corrosion problem while suppressing a bio-fouling phenomenon.

In the plasma underwater discharge, corona discharge and arc discharge can be used by varying pulses and voltages applied to the plasma electrode. The plasma treatment of water discharges the cells by shock waves, cell destruction by ultrasonic waves, and high voltage electric fields. Cell destruction by such effect.

First, in cell destruction by shock waves, shock waves appearing as sudden pressure fluctuations may cause cell destruction, wherein the destruction of cells depends on the size and shape of the cells, the thickness of the cells, and the like, and depends on the shock wave strength.

In addition, in the case of cell destruction by the ultrasonic wave, the ultrasonic wave passes through the liquid, causing cavitation, and when the ultrasonic wave passes through the liquid medium, it generates a longitudinal wave vibrated by the vibrator so that the density of the liquid is small. It creates a dense part, and when the small part is lower than the vapor pressure of the liquid, it creates a bubble and it explodes. It destroys cells by using the shock wave caused by the explosion, and is mainly used when destroying a small amount of microbial cells.

In addition, cell destruction by a high voltage electric field induces a high potential difference in the cell membrane to destroy an insulator called a cell membrane, and microorganisms such as plankton and bacteria are caused by the action of ultraviolet rays, active species, shock waves, and bubbles generated by plasma treatment. Survival can be dramatically reduced.

As shown in FIG. 5, the reactor 110 constituting the plasma treatment tank 100 includes an inlet 111 through which the water to be treated flows in and an outlet 112 through which the water to be treated is discharged. Backwash concentrated water can be accommodated. The reactor 110 is not particularly limited, and may be manufactured in various shapes, and generally may be manufactured in a rectangular parallelepiped shape. One side of the reactor 110 may be provided with a ground electrode 120, the other side may be provided with a plasma electrode 130 for generating a plasma.

Although the position of the inlet 111 and the outlet 112 is not particularly limited, it is preferable that the inlet 111 and the outlet 112 are located on the same side (in the case of a rectangular parallelepiped, meaning the same side). In addition, the ground electrode 120, the inlet 111, and the outlet 112 may be provided at the same side, and the plasma electrode 130 may be installed to face the ground electrode 120.

In this case, the flat ground electrode 120 may form an upper surface of the reactor 110 (see FIG. 5), and may form an inlet 111 and an outlet 112 in the ground electrode 120. .

In addition, as shown in FIG. 6, the reactor 110 may further include a distance controller 140 capable of adjusting a distance between the ground electrode 120 and the plasma electrode 130. The voltage applied to the plasma electrode 130 or the distance between the ground electrode 120 and the plasma electrode 130 may be adjusted according to the type of the backwashed concentrated water, which is the water to be treated. The distance controller 140 may include a reactor ( It is formed to face both sides of the 110 to increase or contract the height of the reactor 110 to adjust the water treatment capacity of the reactor 110 and at the same time the gap between the ground electrode 120 and the plasma electrode 130 Can be adjusted.

A common electrode may be used as the ground electrode 120, and may be provided on one side of the reactor 110 as described above, and may be formed in a flat shape to form one surface of the reactor 110. The ground electrode 120 is electrically connected (contacted) with the water to be treated so that the water can be grounded.

The plasma electrode 130 used in the present invention may be manufactured using tungsten or stainless steel, and may be connected to a power supply (not shown). The power supply unit may apply a pulse, alternating current, or direct current voltage to the plasma electrode 130. The plasma electrode 130 may be provided at one side of the reactor 110, but may be formed separately, but may be located inside the reactor in the form of a plasma electrode module 150 in which a plurality of plasma electrodes are collected. It is preferable to be installed opposite to 120). In addition, the plasma electrode module 150 may be provided in plural in the reactor according to the throughput of the water to be treated.

7 schematically illustrates a plasma electrode 130 that may be used in the present invention. Referring to FIG. 7, the plasma electrode 130 will be described in detail. The plasma electrode 130 may be formed in an integrated structure including a discharge part 131, a fixing part 132, and a ground part 133. have. By being manufactured integrally as described above, it is possible to prevent breakage by applying more power than necessary to one electrode end, thereby improving durability, and there is an advantage in that the plasma electrode 130 is easily replaced later.

In addition, the electrode of each stage is not particularly limited, and may be manufactured in various shapes, but in order to stably generate a plasma, it is preferable that the electrode is formed, and the diameter of the discharge part 131 disposed on the uppermost is shortest. It is preferable that the diameter of the grounding part 133 located at the bottom is the longest (see FIG. 7).

By decreasing the diameter toward the top, the insulation efficiency and the discharge efficiency of the plasma electrode 130 can be improved. In order to maximize the insulation efficiency and the discharge efficiency of the plasma electrode 130, the discharge part 131 and the fixing part 132 are provided. And a ratio of the diameter d of the ground portion 133 to a ratio of 1 to 2: 8 to 10: 12 to 16, and preferably includes a discharge portion 131, a fixing portion 132, and a ground portion 133. It is more preferable to adjust the ratio of the height h of 1: 1 to 1-2.

The plasma electrode may be installed separately in the reactor for water treatment, but may be installed in the reactor in the form of an electrode module in which a plurality of electrodes are disposed.

One embodiment of the plasma electrode module 150 may include a plate form of FIG. 8 (a) and a tube form of FIG. 8 (b), wherein the conductive substrate 152 and the holes in which a plurality of holes 151 are formed may be formed. It may be composed of a ceramic layer 153 surrounding the outer periphery of the tungsten substrate.

The plasma electrode described above is located inside the hole, and includes a plasma electrode having a multi-stage structure in which a ground portion 133 having a circumferential shape, a fixing portion 132, and a discharge portion 131 are sequentially stacked. The ground part 133 is in contact with the conductive substrate, and plasma is generated in the discharge part 131.

According to the shape of the conductive substrate may be implemented as a plate-shaped plasma electrode module and a tube-shaped plasma electrode module, it can be selectively used according to the shape of the water treatment reactor.

As the conductive substrate, tungsten alloy material such as tungsten or tungsten nitride having high electrical conductivity and excellent durability is preferably used. The plasma electrode included in the plasma electrode module may include a ground part 133 and a fixing part 132. And the discharge unit 131 is preferably an integral structure made of the same material having corrosion resistance, the material having corrosion resistance while forming the integral structure is more preferably made of SUS material.

The ratio of the diameters of the ground portion 133, the fixed portion 132, and the discharge portion 131 of the plasma electrode is preferably 7 to 8: 4 to 6: 1, and the ground portion 133 and the fixed portion 132 ) And the height of the discharge unit 131 is preferably 1 to 2: 1: 1.

The conductive substrate may be in the form of a plate or cylinder, and tungsten material is preferably used.

Next, the arrangement of the plasma processing tank 100 using the plasma underwater discharge will be described. As described above with reference to FIG. 4, the plasma is treated using the plasma treatment tank 100 to give the effect of decomposition of organic matter contained in the concentrated water or sterilization or sterilization of microorganisms. Processing can be performed.

In this case, it is preferable to use a plurality of plasma processing tanks 100 in order to increase the efficiency of the plasma processing, and as shown in FIG. 9, the plurality of plasma processing tanks 100 are arranged in series so as to concentrate the concentrated water used for backwashing. It is also possible to process, and it is also possible to perform a plasma treatment using a plurality of plasma processing tanks 100 arranged in parallel with respect to the concentrated water to be treated as shown in FIG.

9 illustrates a plasma processing process in which a plurality of plasma processing tanks 100 are connected in series according to an embodiment of the present invention, and the serially connected plasma processing system 200 includes a plurality of plasma processing tanks 100 connected in series. It can include;

The plasma processing tank 100 has a reactor 110 including an inlet 111 through which concentrated water used as backwashed water, which is treated water, and an outlet 112 through which backwashed water, which is plasma treated water is discharged, is discharged. ); A ground electrode 120 provided at one side of the reactor 110; And a plasma electrode 130 provided at one side of the reactor 110 and generating a plasma. The plasma electrode 130 is typically used in plural numbers, and the reactor 110 is formed in the form of the plasma electrode module 150. ) May be located inside, and the plasma processing tank 100 described above with reference to FIG. 5 or 6 may be used.

While the concentrated water used as the backwash water is sequentially passed through the plurality of plasma processing tanks 100, the concentrated water, which is the water to be treated, may be treated by plasma. In the case of the plasma water treatment system 200 connected in series, the degree of contamination Is useful for purifying concentrated water that is severely treated.

In other words, plasma water discharge is performed several times in concentrated water, which is the water to be treated which may cause bio fouling phenomenon in the subsequent treatment process in which many organics and microorganisms are present inside, thereby more effectively removing the organic matter and microorganisms in the water to be treated. Can be removed

FIG. 10 illustrates a plasma water treatment system 300 in which plasma treatment vessels 100 are connected in parallel, including a plurality of plasma treatment vessels 100 connected in parallel. The tank 100 may have the same structure and shape as the plasma processing tank 100 described above.

The plasma water treatment system 300 may purify the water to be treated while simultaneously supplying concentrated water, which is supplied water, to be supplied to the plurality of plasma processing tanks 100 at the same time. It is useful for plasma treatment of concentrated water, which is a large amount of water to be treated.

Each serial 200 or parallel 300 plasma processing system of FIGS. 9 and 10 measures the concentration of organic contaminants or microorganisms in the backwash water in advance, and controls opening / closing of the valve through a separate control unit. By doing so, it is also possible to selectively drive by controlling the inflow path of the concentrated water.

[ Example  One]

1 and 2, in the case of performing backwashing using the existing primary treated water (STD BW) and backwashing using the high concentration of concentrated water according to the present invention (Brine BW) for about 120 days, respectively. While operating the water purification system, the change in the pressure difference (ΔP) of the filtration membrane module and the turbidity of the produced fresh water were measured.

In each case, the ultrafiltration membrane module was used as the filtration membrane module, and the recovery rate of the reverse osmosis membrane module was fixed at 45%. In addition, when backwashing was performed using the brine, the salt concentration in the brine was kept constant at 70,000 ppm.

As a result of this comparative experiment, the change in pressure difference ΔP over time of the filtration membrane module is shown in FIG. 3. During the initial T1 time, both were backwashed through the first treated water in the same manner, and then the backwashing was performed by applying different backwashing methods during the time of T2 to reduce the pressure difference of the UF filtration module. Measured.

In addition, Table 1 summarizes the results of comparing the turbidity of the fresh water produced during the comparison experiment.

Average Turbidty [NTU]  Std. Dev. [NTU] Brine bw 0.061 ± 0.1 STD BW 0.067 ± 0.01

As shown in the results of FIG. 3 and Table 1, it can be seen that there is no significant difference in the case of using the conventional back washing (STD BW) method and the operating performance of the produced fresh water and the filtration membrane module.

[ Example  2]

In order to confirm the discharge characteristics according to the diameter of the discharge portion of the repair electrode plasma electrode according to an embodiment, the degree of generation of ozone (O3) by using the plasma electrode formed in the circumferential form of the ground portion, the fixed portion and the discharge portion It was.

After maintaining the lengths of the ground part, the fixing part, and the discharge part at 16 mm, 11 mm, and 11 mm, respectively, the concentration of ozone generated by applying current while changing the diameter of the discharge part in various ranges was measured. Ozone is generated by the plasma generated at the discharge end of the electrode, and this ozone has an important effect on the decomposition of contaminants such as reduction of TOC during plasma water treatment.

The diameter of the discharge part was changed to a range of 1 to 4 mm, and the ratio of the diameters of the ground part 133, the fixing part 132, and the discharge part 131 was kept constant at 7.5: 5: 1, and the same voltage was obtained. The result of measuring the concentration of ozone generated by adding is shown in Table 2 below.

Diameter of discharge part [mm] One 2 3 4 Generated O3 Concentration [ppm] - 0.06 0.07 0.0001

As can be seen from the results of Table 2, when the diameter of the discharge portion is too low, it can be seen that the generation of ozone is insignificant due to the plasma not being formed properly, and when the diameter is too large, uniformly on the surface of the discharge portion It was confirmed that the amount of ozone generated as a whole was reduced because no plasma was generated.

As described above, the present invention has been described in detail, and one embodiment of the present invention shown in the drawings will be apparent that the present invention should not be interpreted as limiting the spirit. In addition, the scope of the present invention is defined by the matters set forth in the claims, and those skilled in the art of the present invention can improve and change the technical spirit of the present invention in various forms, such improvements and As long as the changes are obvious to those skilled in the art, they will fall within the scope of the present invention.

10: filtration membrane module 20: first reservoir
30, 60: pump 40: reverse osmosis membrane module
50: second reservoir 70: salt meter
80: drying unit 90: salt supply
100: control unit

Claims (30)

Filtration membrane module supplied with raw water;
A first storage tank for storing pretreated water through the filtration membrane module;
A reverse osmosis membrane module to which the treated water of the first reservoir is supplied;
A second storage tank storing concentrated water discharged from the reverse osmosis membrane module; And
And a backwash pump for supplying the concentrated water stored in the second reservoir to the backwash water of the filtration membrane module.
Concentrated water supplied to the backwash water, after the backwashing process of the filtration membrane module, at least a part is recovered back to the second storage tank,
The concentrated water recovered by the second storage tank is subjected to a plasma treatment tank including a plasma electrode for water treatment.
The plasma processing tank includes a reactor having an inlet through which concentrated water is introduced and an outlet through which plasma-treated concentrate is discharged; A ground electrode provided at one side of the reactor; And a plasma electrode module provided at one side of the reactor and generating a plasma.
The plasma electrode module may include a tungsten base having a plurality of holes formed therein; A ceramic layer surrounding the outer circumference of the tungsten base except for the hole; And a plasma electrode positioned inside the hole and having a multi-stage structure in which a ground part 33 having a circumferential shape, a fixing part 32, and a discharge part 31 are sequentially stacked.
The grounding portion (33) is in contact with the tungsten substrate, characterized in that the plasma is generated in the discharge portion (31), backwash apparatus using a reverse osmosis membrane concentrated water.
The method of claim 1,
The filtration membrane module, characterized in that the microfiltration membrane (microfiltration membrane) or ultrafiltration (ultrafiltration) module, reverse washing apparatus using a reverse osmosis membrane concentrated water.
The method of claim 1,
A pump for transferring the treated water is installed between the first reservoir and the reverse osmosis membrane module.
The method of claim 1,
And the second reservoir is a backwash pressure vessel or a pressure tank.
The method of claim 1,
The salt concentration of the concentrated water supplied to the backwashing water is 50,000 ~ 70,000ppm, backwashing apparatus using the reverse osmosis membrane concentrated water.
The method of claim 1,
The second storage tank includes a salt supply unit for supplying additional salts so as to increase the salt concentration of the stored concentrated water, the reverse osmosis membrane using the concentrated water.
The method of claim 6,
The salts supplied through the salt supply unit, NaCl, CaCl2 or KCl, characterized in that the reverse osmosis membrane concentrated water washing apparatus.
The method of claim 6,
The second storage tank, a backwashing apparatus using a reverse osmosis membrane concentrated water, characterized in that the salt measuring device that can measure the salt concentration of the stored concentrated water.
The method of claim 6,
The concentrated water supplied to the backwashing water is subjected to the backwashing process of the filtration membrane module, and then, at least a part of the backwashing device using the reverse osmosis membrane concentrated water, characterized in that it is supplied to the drying unit, dried with salts, and transferred to the salt supply unit. .
delete delete delete The method of claim 1,
The reactor, characterized in that the ground electrode and the plasma electrode module is installed so as to face, reverse washing apparatus using the reverse osmosis membrane concentrated water.
The method of claim 1,
The reactor, the distance adjusting unit for adjusting the distance between the ground electrode and the plasma electrode module; further characterized in that it is further provided, reverse washing apparatus using the reverse osmosis membrane concentrated water.
The method of claim 1,
The ground electrode is a plate-shaped, characterized in that the reverse osmosis membrane concentrated water using the reverse water.
The method of claim 1,
The grounding part (33), the fixing part (32) and the discharge part (31) is characterized in that the unitary structure made of the same material having corrosion resistance, reverse washing apparatus using the reverse osmosis membrane concentrated water.
The method of claim 1,
The ratio of the diameters of the ground part 33, the fixing part 32 and the discharge part 31 is 7 to 8: 4: 6 to 1, characterized in that the reverse osmosis membrane concentrated water washing apparatus.
The method of claim 1,
The ratio of the height of the ground portion 33, the fixing portion 32 and the discharge portion 31 is characterized in that 1 ~ 2: 1: 1, backwash apparatus using a reverse osmosis membrane concentrated water.
The method of claim 16,
The unitary structure is characterized in that the SUS material having corrosion resistance, reverse washing apparatus using the reverse osmosis membrane concentrated water.
Supplying raw water to the filtration membrane module;
Storing the pre-treated water through the filtration membrane module in a first reservoir;
Supplying the treated water stored in the first reservoir to the reverse osmosis membrane module;
Storing the concentrated water discharged from the reverse osmosis membrane module in a second storage tank;
A back washing supply step of supplying the concentrated water stored in the second storage tank to the back washing water of the filtration membrane module; And
And after the backwashing supplying step, the concentrated water obtained by backwashing the filtration membrane module is supplied to a drying unit or a second storage tank.
Between the step of storing the concentrated water in a second reservoir and a backwash feed step,
Measuring the salt concentration of the stored concentrated water; And
When the salt concentration of the stored concentrated water is lower than 50,000 ~ 70,000ppm, Salt supply step of supplying additional salts through the salt supply unit;
Wherein the drying unit, the concentrated water obtained by backwashing the filtration membrane module to form a salt, wherein the salt formed in the drying unit is supplied to the salt supply, reverse washing method using a reverse osmosis membrane concentrated water.
The method of claim 20,
The filtration membrane module, the microfiltration membrane (microfiltration membrane) or ultrafiltration (ultrafiltration) module, the reverse washing method using a reverse osmosis membrane concentrated water.
The method of claim 20,
The treated water stored in the first reservoir is supplied to the reverse osmosis membrane module by a pump, the reverse washing method using the reverse osmosis membrane concentrated water.
The method of claim 20,
The salt concentration of the concentrated water supplied to the backwashing water is characterized in that 50,000 ~ 70,000ppm, backwashing method using the reverse osmosis membrane concentrated water.
The method of claim 20,
The salt further supplied in the salt supply step is NaCl, CaCl ₂ or KCl, characterized in that the reverse osmosis membrane concentrated water using a reverse water.
delete delete delete delete The method of claim 20,
Between the step of storing the concentrated water in a second reservoir and a backwash feed step,
Measuring the salt concentration of the stored concentrated water; And
When the salt concentration of the stored concentrated water is higher than 50,000 ~ 70,000ppm, Fresh water supply step of supplying a portion of the production water discharged from the reverse osmosis membrane module to the second storage tank; further comprising a reverse osmosis membrane concentrated water Backwash method used.
The method of claim 20,
After the backwash supply step,
And a plasma treatment step of plasma-processing the concentrated water after being used as the backwash water through a plasma treatment tank including a plasma electrode for water treatment. The backwashing method using the reverse osmosis membrane concentrated water.

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